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1
Poirson, Philippe. "Pic de particules fines et inertie des autorités". Revue Médicale Suisse 4, n. 146 (2008): 559a. http://dx.doi.org/10.53738/revmed.2008.4.146.559a.
2
Gallinari, F., S. Elmaleh e R. Ben Aïm. "Influence de la dissipation énergetique sur l'efficacité de la flottation à air dissous : analogie avec la floculation". Revue des sciences de l'eau 9, n. 4 (12 aprile 2005): 485–98. http://dx.doi.org/10.7202/705263ar.
Abstract (sommario):
Les flottateurs à air dissous sont classiquement dimensionnés à partir de deux paramètres: le rapport mA/mS des masses d'air et de solides en présence et le temps de contact entre phases. Une série d'essais effectués sur cinq différentes unités continues ou discontinues montre que ces seules variables opératoires ne suffisent pas à déterminer l'efficacité. De plus, l'extrapolation des données obtenues sur un floculateur discontinu conduirait à des besoins en air dissous considérables pouvant limiter le développement industriel. La dissipation d'énergie, habituellement négligée, peut être quantifiée par le gradient de vitesse tel qu'il a été introduit en théorie de la floculation. De plus, une analogie entre la capture bulles-particules et le processus de floculation des particules primaires sur les flocs déjà formés permet d'étendre les équations de vitesse de la floculation et d'obtenir un modèle cinétique où interviennent seulement le gradient de vitesse et la concentration de particules; ce modèle remplace avantageusement l'approche classique qui considère la flottation comme un processus du premier ordre par rapport aux particules. L'efficacité d'une cellule discontinue ou d'un floculateur piston est alors fonction du seul nombre de Camp. Les résultats montrent l'existence d'un intervalle optimal pour le gradient de vitesse, 3000 à 4000 s-¹, et pour le nombre de Camp 105 à 106. Le modèle devra être amélioré par introduction de la tension critique de mouillage des particules.
3
Hengé-Napoli, M. H., E. Ansoborlo, V. Chazel, R. Gibert, P. Houpert, F. Paquet e L. Zhang. "Interaction uranium-cellule cible : exemple de la transformation de particules d'UO4dans le macrophage alvéolaire". Radioprotection 32, n. 5 (dicembre 1997): 625–36. http://dx.doi.org/10.1051/radiopro:1997121.
4
Fortin, JF, R. Cantin e MJ Tremblay. "Présence des protéines de la cellule hôte sur les particules virales : influences sur le cycle de vie du VIH-1." médecine/sciences 17, n. 2 (2001): 186. http://dx.doi.org/10.4267/10608/1891.
5
Krug, S. A., S. L. Eggers e B. Matthiessen. "High nitrate to phosphorus ratio attenuates negative effects of rising <i>p</i>CO<sub>2</sub> on net population carbon accumulation". Biogeosciences Discussions 8, n. 4 (11 luglio 2011): 6833–57. http://dx.doi.org/10.5194/bgd-8-6833-2011.
Abstract (sommario):
Abstract. The ongoing rise in atmospheric pCO2 and the consequent increase in ocean acidification have direct effects on marine calcifying phytoplankton which potentially translates into altered carbon export. To date it remains unclear first, how nutrient ratio, in particular from coccolithophores preferred phosphate limitation, interacts with pCO2 on particulate carbon accumulation. Second, how direct physiological responses on the cellular level translate into a net population response. In this study cultures of Emiliania huxleyi were full-factorially exposed to two different N:P ratios (Redfield and high N:P) and three different pCO2 levels. Effects on net population particulate inorganic and organic carbon (PIC, POC) were measured after E. huxleyi cultures reached stationary phase. Thereby cell sizes and total cell abundance were taken into account. Corresponding to literature results show a significant negative cellular PIC and POC response which, however, was strongest under high N:P ratio. In contrast, net population PIC and POC accumulation was significantly attenuated under high N:P ratio. We suggest that less cellular nutrient accumulation allowed for higher cell abundances which compensated for the strong negative cellular PIC and POC response to pCO2 on the population level. Moreover, the design of this study also allowed following natural alteration of carbon chemistry through changing DIC and alkalinity. Our results suggest that at high initial pCO2 natural alteration of pCO2 during the experimental runtime was regulated by algal biomass. In contrast, at low initial pCO2 the PIC/POC ratio was responsible for changes in pCO2. Our results point to the fact that the physiological (i.e. cellular) PIC and POC response to ocean acidification cannot be linearly extrapolated to total population response and thus carbon export. It is therefore recommended to consider effects of nutrient limitation on cell physiology and translate these to net population carbon accumulation when predicting the influence of coccolithophores on both, the atmospheric pCO2 feedback and their function in carbon export mechanisms.
6
Brajkovic, S., D. Favre, G. Niederhäuser, R. Regazzi, G. Waeber e A. Abderrahmani. "P241 L’induction du stress du réticulum endoplasmique contribue au dysfonctionnement de la cellule bêta provoquée par les particules de LDL oxydées". Diabetes & Metabolism 35 (marzo 2009): A84. http://dx.doi.org/10.1016/s1262-3636(09)72039-7.
7
Ito, Sayuri, Eisuke Gotoh, Shigeru Ozawa e Kazuo Yanagi. "Epstein–Barr virus nuclear antigen-1 is highly colocalized with interphase chromatin and its newly replicated regions in particular". Journal of General Virology 83, n. 10 (1 ottobre 2002): 2377–83. http://dx.doi.org/10.1099/0022-1317-83-10-2377.
Abstract (sommario):
Epstein–Barr virus (EBV) nuclear antigen-1 (EBNA-1), which binds to both the EBV origin of replication (oriP) and metaphase chromosomes, is essential for the replication/retention and segregation/partition of oriP-containing plasmids. Here the chromosomal localization of EBNA-1 fused to green fluorescent protein (GFP–EBNA-1) is examined by confocal microscopy combined with a ‘premature chromosome condensation’ (PCC) procedure. Analyses show that GFP–EBNA-1 expressed in living cells that lack oriP plasmids is associated with cellular chromatin that has been condensed rapidly by the PCC procedure into identifiable forms that are unique to each phase of interphase as well as metaphase chromosomes. Studies of cellular chromosomal DNAs labelled with BrdU or Cy3-dUTP indicate that GFP–EBNA-1 colocalizes highly with the labelled, newly replicated regions of interphase chromatin in cells. These results suggest that EBNA-1 is associated not only with cellular metaphase chromosomes but also with condensing chromatin/chromosomes and probably with interphase chromatin, especially with its newly replicated regions.
8
Matthiessen, B., S. L. Eggers e S. A. Krug. "High nitrate to phosphorus regime attenuates negative effects of rising <i>p</i>CO<sub>2</sub> on total population carbon accumulation". Biogeosciences 9, n. 3 (28 marzo 2012): 1195–203. http://dx.doi.org/10.5194/bg-9-1195-2012.
Abstract (sommario):
Abstract. The ongoing rise in atmospheric pCO2 and consequent increase in ocean acidification have direct effects on marine calcifying phytoplankton, which potentially alters carbon export. To date it remains unclear, firstly, how nutrient regime, in particular by coccolithophores preferred phosphate limitation, interacts with pCO2 on particulate carbon accumulation; secondly, how direct physiological responses on the cellular level translate into total population response. In this study, cultures of Emiliania huxleyi were full-factorially exposed to two different N:P regimes and three different pCO2 levels. Cellular biovolume and PIC and POC content significantly declined in response to pCO2 in both nutrient regimes. Cellular PON content significantly increased in the Redfield treatment and decreased in the high N:P regime. Cell abundance significantly declined in the Redfield and remained constant in the high N:P regime. We hypothesise that in the high N:P regime severe phosphorous limitation could be compensated either by reduced inorganic phosphorous demand and/or by enzymatic uptake of organic phosphorous. In the Redfield regime we suggest that enzymatic phosphorous uptake to supplement enhanced phosphorous demand with pCO2 was not possible and thus cell abundance declined. These hypothesised different physiological responses of E. huxleyi among the nutrient regimes significantly altered population carrying capacities along the pCO2 gradient. This ultimately led to the attenuated total population response in POC and PIC content and biovolume to increased pCO2 in the high N:P regime. Our results point to the fact that the physiological (i.e. cellular) PIC and POC response to ocean acidification cannot be linearly extrapolated to total population response and thus carbon export. It is therefore necessary to consider both effects of nutrient limitation on cell physiology and their consequences for population size when predicting the influence of coccolithophores on atmospheric pCO2 feedback and their function in carbon export mechanisms.
9
Lukaszuk, Bartlomiej, Agnieszka Miklosz, Adrian Chabowski e Jan Górski. "Modest Decrease in Pgc1α Results in TAG Accumulation but not in Insulin Resistance in L6 Myotubes". Cellular Physiology and Biochemistry 35, n. 4 (2015): 1609–22. http://dx.doi.org/10.1159/000373975.
Abstract (sommario):
Background/Aims: PGC-1α is an important cellular protein (coactivator) regulating myocyte mitochondria number and function, and therefore whole cellular energy status. The aim of this work was to investigate the effects of modest, temporary PGC-1α knock-down on L6 myotubes insulin resistance in a light of cellular lipid metabolism. Methods: Gas liquid chromatography was applied for assessing FAs content and composition. For the expression of mitochondrial enzymes, as well as FA and glucose transporters, Western Blot technique was adopted. Additionally, radiolabelled glucose and palmitic acid uptake was performed to estimate the nutrients cellular influx. Results: Modest (-24%) PGC-1α protein ablation resulted in decreased mitochondrial activity in general (reduced Cyt C content) and FAs oxidation in particular (diminished β-HAD expression) without increased FAs cellular influx. The aforementioned intervention led to significantly increased TAG cellular level, but not DAG nor CER. Consequently, no changes in cellular insulin responsiveness were noticed. Conclusions: Modest (-24%) PGC-1α protein depletion results in lipid accumulation, without causing insulin resistance. Importantly, it seems that this TAG loading is a result of decreased mitochondrial oxidative capacity and/or possibly increased lipid biosynthesis but not fatty acid cellular influx.
10
Lopez, Katherine C., Sridhar Kandala, Scott Marek e Deanna M. Barch. "Development of Network Topology and Functional Connectivity of the Prefrontal Cortex". Cerebral Cortex 30, n. 4 (6 dicembre 2019): 2489–505. http://dx.doi.org/10.1093/cercor/bhz255.
Abstract (sommario):
Abstract The prefrontal cortex (PFC) comprises distinct regions and networks that vary in their trajectories across development. Further understanding these diverging trajectories may elucidate the neural mechanisms by which distinct PFC regions contribute to cognitive maturity. In particular, it remains unclear whether PFC regions of distinct network affiliations differ in topology and their relationship to cognition. We examined 615 individuals (8–21 years) to characterize age-related effects in participation coefficient of 28 PFC regions of distinct networks, evaluating connectivity profiles of each region to understand patterns influencing topological maturity. Findings revealed that PFC regions of attention, frontoparietal, and default mode networks (DMN) displayed varying rates of decline in participation coefficient with age, characterized by stronger connectivity with each PFC’s respective network; suggesting that PFC regions largely aid network segregation. Conversely, PFC regions of the cinguloopercular/salience network increased in participation coefficient with age, marked by stronger between-network connections, suggesting that some PFC regions feature a distinctive ability to facilitate network integration. PFC topology of the DMN, in particular, predicted improvements in global cognition, including motor speed and higher order abilities. Together, these findings elucidate systematic differences in topology across PFC regions of different network affiliation, representing important neural signatures of typical brain development.
11
Liang, Huiyun, e Walter F. Ward. "PGC-1α: a key regulator of energy metabolism". Advances in Physiology Education 30, n. 4 (dicembre 2006): 145–51. http://dx.doi.org/10.1152/advan.00052.2006.
Abstract (sommario):
Peroxisome proliferator-activated receptor-γ coactivator (PGC)-1α is a member of a family of transcription coactivators that plays a central role in the regulation of cellular energy metabolism. It is strongly induced by cold exposure, linking this environmental stimulus to adaptive thermogenesis. PGC-1α stimulates mitochondrial biogenesis and promotes the remodeling of muscle tissue to a fiber-type composition that is metabolically more oxidative and less glycolytic in nature, and it participates in the regulation of both carbohydrate and lipid metabolism. It is highly likely that PGC-1α is intimately involved in disorders such as obesity, diabetes, and cardiomyopathy. In particular, its regulatory function in lipid metabolism makes it an inviting target for pharmacological intervention in the treatment of obesity and Type 2 diabetes.
12
Bakkar, Nadine, Katherine Ladner, Benjamin D. Canan, Sandya Liyanarachchi, Naresh C. Bal, Meghna Pant, Muthu Periasamy, Qiutang Li, Paul M. L. Janssen e Denis C. Guttridge. "IKKα and alternative NF-κB regulate PGC-1β to promote oxidative muscle metabolism". Journal of Cell Biology 196, n. 4 (20 febbraio 2012): 497–511. http://dx.doi.org/10.1083/jcb.201108118.
Abstract (sommario):
Although the physiological basis of canonical or classical IκB kinase β (IKKβ)–nuclear factor κB (NF-κB) signaling pathway is well established, how alternative NF-κB signaling functions beyond its role in lymphoid development remains unclear. In particular, alternative NF-κB signaling has been linked with cellular metabolism, but this relationship is poorly understood. In this study, we show that mice deleted for the alternative NF-κB components IKKα or RelB have reduced mitochondrial content and function. Conversely, expressing alternative, but not classical, NF-κB pathway components in skeletal muscle stimulates mitochondrial biogenesis and specifies slow twitch fibers, suggesting that oxidative metabolism in muscle is selectively controlled by the alternative pathway. The alternative NF-κB pathway mediates this specificity by direct transcriptional activation of the mitochondrial regulator PPAR-γ coactivator 1β (PGC-1β) but not PGC-1α. Regulation of PGC-1β by IKKα/RelB also is mammalian target of rapamycin (mTOR) dependent, highlighting a cross talk between mTOR and NF-κB in muscle metabolism. Together, these data provide insight on PGC-1β regulation during skeletal myogenesis and reveal a unique function of alternative NF-κB signaling in promoting an oxidative metabolic phenotype.
13
Ye, Huanpeng, Guangye Li, Xinjun Sheng e Xiangyang Zhu. "Phase-amplitude coupling between low-frequency scalp EEG and high-frequency intracranial EEG during working memory task". Journal of Neural Engineering 19, n. 2 (1 aprile 2022): 026043. http://dx.doi.org/10.1088/1741-2552/ac63e9.
Abstract (sommario):
Abstract Objective. Revealing the relationship between simultaneous scalp electroencephalography (EEG) and intracranial electroencephalography (iEEG) is of great importance for both neuroscientific research and translational applications. However, whether prominent iEEG features in the high-gamma band can be reflected by scalp EEG is largely unknown. To address this, we investigated the phase-amplitude coupling (PAC) phenomenon between the low-frequency band of scalp EEG and the high-gamma band of iEEG. Approach. We analyzed a simultaneous iEEG and scalp EEG dataset acquired under a verbal working memory paradigm from nine epilepsy subjects. The PAC values between pairs of scalp EEG channel and identified iEEG channel were explored. After identifying the frequency combinations and electrode locations that generated the most significant PAC values, we compared the PAC values of different task periods (encoding, maintenance, and retrieval) and memory loads. Main results. We demonstrated that the amplitude of high-gamma activities in the entorhinal cortex, hippocampus, and amygdala was correlated to the delta or theta phase at scalp locations such as Cz and Pz. In particular, the frequency bin that generated the maximum PAC value centered at 3.16–3.84 Hz for the phase and 50–85 Hz for the amplitude. Moreover, our results showed that PAC values for the retrieval period were significantly higher than those of the encoding and maintenance periods, and the PAC was also influenced by the memory load. Significance. This is the first human simultaneous iEEG and scalp EEG study demonstrating that the amplitude of iEEG high-gamma components is associated with the phase of low-frequency components in scalp EEG. These findings enhance our understanding of multiscale neural interactions during working memory, and meanwhile, provide a new perspective to estimate intracranial high-frequency features with non-invasive neural recordings.
14
Verheijen, Bert M., Satoru Morimoto, Ryogen Sasaki, Kiyomitsu Oyanagi, Yasumasa Kokubo, Shigeki Kuzuhara e Fred W. van Leeuwen. "Expression of Mutant Ubiquitin and Proteostasis Impairment in Kii Amyotrophic Lateral Sclerosis/Parkinsonism-Dementia Complex Brains". Journal of Neuropathology & Experimental Neurology 79, n. 8 (1 agosto 2020): 902–7. http://dx.doi.org/10.1093/jnen/nlaa056.
Abstract (sommario):
Abstract Kii amyotrophic lateral sclerosis/parkinsonism-dementia complex (ALS/PDC) is a progressive neurodegenerative disorder that is endemic to the Kii peninsula of Japan. The disorder is clinically characterized by a variable combination of parkinsonism, dementia, and motor neuron symptoms. Despite extensive investigations, the etiology and pathogenesis of ALS/PDC remain unclear. At the neuropathological level, Kii ALS/PDC is characterized by neuronal loss and tau-dominant polyproteinopathy. Here, we report the accumulation of several proteins involved in protein homeostasis pathways, that is, the ubiquitin-proteasome system and the autophagy-lysosome pathway, in postmortem brain tissue from a number of Kii ALS/PDC cases (n = 4). Of particular interest is the presence of a mutant ubiquitin protein (UBB+1), which is indicative of disrupted ubiquitin homeostasis. The findings suggest that abnormal protein aggregation is linked to impaired protein homeostasis pathways in Kii ALS/PDC.
15
Beck, Christian, Stefanie Hertel, Anne Rediger, Robert Lehmann, Anika Wiegard, Adrian Kölsch, Beate Heilmann, Jens Georg, Wolfgang R. Hess e Ilka M. Axmann. "Daily Expression Pattern of Protein-Encoding Genes and Small Noncoding RNAs in Synechocystis sp. Strain PCC 6803". Applied and Environmental Microbiology 80, n. 17 (13 giugno 2014): 5195–206. http://dx.doi.org/10.1128/aem.01086-14.
Abstract (sommario):
ABSTRACTMany organisms harbor circadian clocks with periods close to 24 h. These cellular clocks allow organisms to anticipate the environmental cycles of day and night by synchronizing circadian rhythms with the rising and setting of the sun. These rhythms originate from the oscillator components of circadian clocks and control global gene expression and various cellular processes. The oscillator of photosynthetic cyanobacteria is composed of three proteins, KaiA, KaiB, and KaiC, linked to a complex regulatory network.Synechocystissp. strain PCC 6803 possesses the standard cyanobacterialkaiABCgene cluster plus multiplekaiBandkaiCgene copies and antisense RNAs for almost everykaitranscript. However, there is no clear evidence of circadian rhythms inSynechocystissp. PCC 6803 under various experimental conditions. It is also still unknown if and to what extent the multiplekaigene copies andkaiantisense RNAs affect circadian timing. Moreover, a large number of small noncoding RNAs whose accumulation dynamics over time have not yet been monitored are known forSynechocystissp. PCC 6803. Here we performed a 48-h time series transcriptome analysis ofSynechocystissp. PCC 6803, taking into account periodic light-dark phases, continuous light, and continuous darkness. We found that expression of functionally related genes occurred in different phases of day and night. Moreover, we found day-peaking and night-peaking transcripts among the small RNAs; in particular, the amounts ofkaiantisense RNAs correlated or anticorrelated with those of their respectivekaitarget mRNAs, pointing toward the regulatory relevance of these antisense RNAs. Surprisingly, we observed that the amounts of 16S and 23S rRNAs in this cyanobacterium fluctuated in light-dark periods, showing maximum accumulation in the dark phase. Importantly, the amounts of all transcripts, including small noncoding RNAs, did not show any rhythm under continuous light or darkness, indicating the absence of circadian rhythms inSynechocystis.
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De Bodt, C., N. Van Oostende, J. Harlay, K. Sabbe e L. Chou. "Individual and interacting effects of <i>p</i>CO<sub>2</sub> and temperature on <i>Emiliania huxleyi</i> calcification: study of the calcite production, the coccolith morphology and the coccosphere size". Biogeosciences 7, n. 5 (5 maggio 2010): 1401–12. http://dx.doi.org/10.5194/bg-7-1401-2010.
Abstract (sommario):
Abstract. The impact of ocean acidification and increased water temperature on marine ecosystems, in particular those involving calcifying organisms, has been gradually recognised. We examined the individual and combined effects of increased pCO2 (180 ppmV CO2, 380 ppmV CO2 and 750 ppmV CO2 corresponding to past, present and future CO2 conditions, respectively) and temperature (13 °C and 18 °C) during the exponential growth phase of the coccolithophore E. huxleyi using batch culture experiments. We showed that cellular production rate of Particulate Organic Carbon (POC) increased from the present to the future CO2 treatments at 13 °C. A significant effect of pCO2 and of temperature on calcification was found, manifesting itself in a lower cellular production rate of Particulate Inorganic Carbon (PIC) as well as a lower PIC:POC ratio at future CO2 levels and at 18 °C. Coccosphere-sized particles showed a size reduction with both increasing temperature and CO2 concentration. The influence of the different treatments on coccolith morphology was studied by categorizing SEM coccolith micrographs. The number of well-formed coccoliths decreased with increasing pCO2 while temperature did not have a significant impact on coccolith morphology. No interacting effects of pCO2 and temperature were observed on calcite production, coccolith morphology or on coccosphere size. Finally, our results suggest that ocean acidification might have a larger adverse impact on coccolithophorid calcification than surface water warming.
17
Maurice, Nicholas M., Brahmchetna Bedi, Zhihong Yuan, Kuo-Chuan Lin, Joanna B. Goldberg, C. Michael Hart, Kristina L. Bailey e Ruxana T. Sadikot. "The Effect of PGC-1alpha-SIRT3 Pathway Activation on Pseudomonas aeruginosa Infection". Pathogens 11, n. 2 (19 gennaio 2022): 116. http://dx.doi.org/10.3390/pathogens11020116.
Abstract (sommario):
The innate immune response to P. aeruginosa pulmonary infections relies on a network of pattern recognition receptors, including intracellular inflammasome complexes, which can recognize both pathogen- and host-derived signals and subsequently promote downstream inflammatory signaling. Current evidence suggests that the inflammasome does not contribute to bacterial clearance and, in fact, that dysregulated inflammasome activation is harmful in acute and chronic P. aeruginosa lung infection. Given the role of mitochondrial damage signals in recruiting inflammasome signaling, we investigated whether mitochondrial-targeted therapies could attenuate inflammasome signaling in response to P. aeruginosa and decrease pathogenicity of infection. In particular, we investigated the small molecule, ZLN005, which transcriptionally activates peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), a master regulator of mitochondrial biogenesis, antioxidant defense, and cellular respiration. We demonstrate that P. aeruginosa infection promotes the expression of inflammasome components and attenuates several components of mitochondrial repair pathways in vitro in lung epithelial cells and in vivo in an acute pneumonia model. ZLN005 activates PGC-1α and its downstream effector, Sirtuin 3 (SIRT3), a mitochondrial-localized deacetylase important for cellular metabolic processes and for reactive oxygen species homeostasis. ZLN005 also attenuates inflammasome signaling induced by P. aeruginosa in bronchial epithelial cells and this action is dependent on ZLN005 activation of SIRT3. ZLN005 treatment reduces epithelial-barrier dysfunction caused by P. aeruginosa and decreases pathogenicity in an in vivo pneumonia model. Therapies that activate the PGC-1α—SIRT3 axis may provide a complementary approach in the treatment of P. aeruginosa infection.
18
Camponeschi, Francesca, e Lucia Banci. "Metal cofactors trafficking and assembly in the cell: a molecular view". Pure and Applied Chemistry 91, n. 2 (25 febbraio 2019): 231–45. http://dx.doi.org/10.1515/pac-2018-0720.
Abstract (sommario):
Abstract Metal ions are essential cofactors required by the proteome of organisms from any kingdom of life to correctly exert their functions. Dedicated cellular import, transport and homeostasis systems assure that the needed metal ion is correctly delivered and inserted into the target proteins and avoid the presence of free metal ions in the cell, preventing oxidative damaging. Among metal ions, in eukaryotic organisms copper and iron are required by proteins involved in absolutely essential functions, such as respiration, oxidative stress protection, catalysis, gene expression regulation. Copper and iron binding proteins are localized in essentially all cellular compartments. Copper is physiologically present mainly as individual metal ion. Iron can be present both as individual metal ion or as part of cofactors, such as hemes and iron-sulfur (Fe-S) clusters. Both metal ions are characterized by the ability to cycle between different oxidation states, which enable them to catalyze redox reactions and to participate in electron transfer processes. Here we describe in detail the main processes responsible for the trafficking of copper and iron sulfur clusters, with particular interest for the structural aspects of the maturation of copper and iron-sulfur-binding proteins.
19
Ndour, N., M. Sarr, A. Deh, MT Ndiaye Diop, B. Seck, MD Kante, Z. Attiya et al. "C88: Liposarcome myxoïde à cellules rondes, métastatique de la fesse". African Journal of Oncology 2, n. 1 Supplement (1 marzo 2022): S37. http://dx.doi.org/10.54266/ajo.2.1s.c88.blie5370.
Abstract (sommario):
INTRODUCTION : Le liposarcome est une tumeur mésenchymateuse primitive rare, développée aux dépends des tissus adipeux. Il est constitué de quatre sous-types histologiques notamment les sous- types bien différenciés, myxoïde, pléomorphe et dédifférencié. La localisation préférentielle est la cuisse. Nous rapportons une observation d’un liposarcome myxoïde à cellule ronde à localisation fessière. OBSERVATION : Un homme âgé de 56 ans, vendeur de légumes, originaire de la Guinée Conakry, présentait depuis deux ans une tumeur de la fesse droite. L’examen retrouvait une tumeur inflammatoire, ulcérée du quadrant supéro-externe de la fesse droite bien limitée, à fond purulent jaunâtre avec quelques plages de nécrose, mesurant environ huit cm. Des adénopathies inguinales bilatérales étaient retrouvées. Les hypothèses diagnostiques étaient les suivantes : carcinome épidermoïde, lymphome cutané, métastases cutanées. L’examen anatomopathologique mettait en évidence une prolifération tumorale maligne occupant toute la hauteur du derme et faite de lipoblastes, de flasques mucineux bleuâtres disposées en vastes zones et des plages d’adipocytes très pléomorphes avec des noyaux irréguliers à disposition interstitielle diffuse. Le diagnostic de liposarcome myxoïde à cellules rondes avait été retenu. La tomodensitométrie thoraco-abdomino-pelvienne, réalisée dans le cadre du bilan l’extension, avais mis en évidence un aspect compatible avec des localisations néoplasiques secondaires pleuropulmonaires, hépatiques, cutanées et ganglionnaires. L’extension ganglionnaire concernaient les aires inguinales et iliaques internes et externes bilatérales avec des adénopathies de tailles variables dont la cible inguinale droite mesure 96x94 mm. Ces adénopathies étaient compressives compliquées d’une urétro-hydronéphrose de stade II à droite et d’une thrombose veineuse cave partielle. Le patient a été traité par chimiothérapie (adriamycine – carboplatine). L’évolution était rapidement fatale au bout de quelques semaines après la première cure de chimiothérapie. Les liposarcomes sont des tumeurs malignes rares représentant moins de 1% des tumeurs malignes. Quatre sous-types histopathologiques sont identifiés par l’OMS. Notre observation est caractéristique par sa topographie et l’évolution rapidement fatale avec des métastases multiples. Le sous-type myxoïde est le plus fréquent représentant 25% des liposarcomes et 5% des sarcomes des tissus mous atteignant généralement les adultes jeunes avec un pic d’incidence entre 40 et 60 ans. CONCLUSION : Il faudrait évoquer un liposarcome devant toute tumeur des parties molles localisée à la région fessière. L’examen anatomopathologique est incontournable pour confirmer le diagnostic et préciser le sous-type histopathologique.
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Gibbs, Samantha J., Rosie M. Sheward, Paul R. Bown, Alex J. Poulton e Sarah A. Alvarez. "Warm plankton soup and red herrings: calcareous nannoplankton cellular communities and the Palaeocene–Eocene Thermal Maximum". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 376, n. 2130 (3 settembre 2018): 20170075. http://dx.doi.org/10.1098/rsta.2017.0075.
Abstract (sommario):
Past global warming events such as the Palaeocene–Eocene Thermal Maximum (PETM—56 Ma) are attributed to the release of vast amounts of carbon into the ocean, atmosphere and biosphere with recovery ascribed to a combination of silicate weathering and organic carbon burial. The phytoplanktonic nannoplankton are major contributors of organic and inorganic carbon but their role in this recovery process remains poorly understood and complicated by their contribution to marine calcification. Biocalcification is implicated not only in long-term carbon burial but also both short-term positive and negative climatic feedbacks associated with seawater buffering and responses to ocean acidification. Here, we use exceptional records of preserved fossil coccospheres to reconstruct cell size distribution, biomass production (particulate organic carbon, POC) and (particulate) inorganic carbon (PIC) yields of three contrasting nannoplankton communities (Bass River—outer shelf, Maud Rise—uppermost bathyal, Shatsky Rise—open ocean) through the PETM onset and recovery. Each of the sites shows contrasting community responses across the PETM as a function of their taxic composition and total community biomass. Our results indicate that nannoplankton PIC:POC had no role in short-term climate feedback and, as such, their importance as a source of CO 2 to the environment is a red herring. It is nevertheless likely that shifts to greater numbers of smaller cells at the shelf site in particular led to greater carbon transfer efficiency, and that nannoplankton productivity and export across the shelves had a significant modulating effect on carbon sequestration during the PETM recovery. This article is part of a discussion meeting issue ‘Hyperthermals: rapid and extreme global warming in our geological past’.
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Toyoshima, Masakazu, Yuma Tokumaru, Fumio Matsuda e Hiroshi Shimizu. "Assessment of Protein Content and Phosphorylation Level in Synechocystis sp. PCC 6803 under Various Growth Conditions Using Quantitative Phosphoproteomic Analysis". Molecules 25, n. 16 (6 agosto 2020): 3582. http://dx.doi.org/10.3390/molecules25163582.
Abstract (sommario):
The photosynthetic apparatus and metabolic enzymes of cyanobacteria are subject to various controls, such as transcriptional regulation and post-translational modifications, to ensure that the entire cellular system functions optimally. In particular, phosphorylation plays key roles in many cellular controls such as enzyme activity, signal transduction, and photosynthetic apparatus restructuring. Therefore, elucidating the governing functions of phosphorylation is crucial to understanding the regulatory mechanisms underlying metabolism and photosynthesis. In this study, we determined protein content and phosphorylation levels to reveal the regulation of intracellular metabolism and photosynthesis in Synechocystis sp. PCC 6803; for this, we obtained quantitative data of proteins and their phosphorylated forms involved in photosynthesis and metabolism under various growth conditions (photoautotrophic, mixotrophic, heterotrophic, dark, and nitrogen-deprived conditions) using targeted proteomic and phosphoproteomic analyses with nano-liquid chromatography-triple quadrupole mass spectrometry. The results indicated that in addition to the regulation of protein expression, the regulation of phosphorylation levels of cyanobacterial photosynthetic apparatus and metabolic enzymes was pivotal for adapting to changing environmental conditions. Furthermore, reduced protein levels of CpcC and altered phosphorylation levels of CpcB, ApcA, OCP, and PsbV contributed to the cellular response of the photosynthesis apparatus to nitrogen deficiency.
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Combrisson, Etienne, Timothy Nest, Andrea Brovelli, Robin A. A. Ince, Juan L. P. Soto, Aymeric Guillot e Karim Jerbi. "Tensorpac: An open-source Python toolbox for tensor-based phase-amplitude coupling measurement in electrophysiological brain signals". PLOS Computational Biology 16, n. 10 (29 ottobre 2020): e1008302. http://dx.doi.org/10.1371/journal.pcbi.1008302.
Abstract (sommario):
Despite being the focus of a thriving field of research, the biological mechanisms that underlie information integration in the brain are not yet fully understood. A theory that has gained a lot of traction in recent years suggests that multi-scale integration is regulated by a hierarchy of mutually interacting neural oscillations. In particular, there is accumulating evidence that phase-amplitude coupling (PAC), a specific form of cross-frequency interaction, plays a key role in numerous cognitive processes. Current research in the field is not only hampered by the absence of a gold standard for PAC analysis, but also by the computational costs of running exhaustive computations on large and high-dimensional electrophysiological brain signals. In addition, various signal properties and analyses parameters can lead to spurious PAC. Here, we present Tensorpac, an open-source Python toolbox dedicated to PAC analysis of neurophysiological data. The advantages of Tensorpac include (1) higher computational efficiency thanks to software design that combines tensor computations and parallel computing, (2) the implementation of all most widely used PAC methods in one package, (3) the statistical analysis of PAC measures, and (4) extended PAC visualization capabilities. Tensorpac is distributed under a BSD-3-Clause license and can be launched on any operating system (Linux, OSX and Windows). It can be installed directly via pip or downloaded from Github (https://github.com/EtienneCmb/tensorpac). By making Tensorpac available, we aim to enhance the reproducibility and quality of PAC research, and provide open tools that will accelerate future method development in neuroscience.
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Rho, Y., e S. Vijayan. "0124 A Prefrontal-Amygdala Network Model of the Cellular and Circuit-Level Mechanisms of Emotional Memory Consolidation During the Awake State and REM Sleep". Sleep 43, Supplement_1 (aprile 2020): A49. http://dx.doi.org/10.1093/sleep/zsaa056.122.
Abstract (sommario):
Abstract Introduction Rapid eye movement (REM) sleep has been implicated in the consolidation of emotional memories. Our recent work found a candidate system for REM-related memory consolidation. We showed that during REM sleep, the frontal cortices are dominated by theta (4–8 Hz) oscillations and bursts of beta (15–35 Hz) activity. Studies suggest that rhythmic interactions between the frontal cortices and limbic structures, in particular the amygdala, play a critical role in the consolidation of emotional memories. However, the mechanisms responsible for memory consolidation during these rhythmic interactions during REM sleep remain unknown. Methods We used biophysically based neural models to build a large-scale network model of the prefrontal cortex (PFC) and amygdala (AMY) and incorporated synaptic plasticity mechanisms, such as spike-timing dependent plasticity (STDP), into the connections between these two regions. Norepinephrine (NE) and serotonin (SE) levels were manipulated to mimic the different physiological conditions during the awake state and REM sleep. Results We were able to reproduce the oscillatory dynamics observed in experimental studies and identify cell-type specific synaptic changes caused by STDP. During the awake state, PFC connections to all cell types of the AMY become strengthened when PFC neurons provide theta frequency inputs, with the connections strengthening to a greater extent when inputs are in burst mode rather than single spike mode. When the PFC provides beta inputs, we see the exact opposite relationship: synaptic strengths become weaker when inputs are in burst mode rather than single spike mode. During REM sleep conditions, the connections to all principal cell types of the AMY become strengthened, with synaptic connections to some subtypes of pyramidal cells becoming stronger than others. Surprisingly, however, the synaptic connections to the interneurons become weaker in response to theta frequency inputs. Conclusion Using our large-scale network model, we show how the levels of the neurotransmitters NE and SE during the awake state and REM sleep affect oscillatory dynamics and in turn influence the strengthening or weakening of connections related to emotional memories. Support United States Army Research Office, Award number ARO W91lNF-17-1-0300
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Cruzeiro, Leonor. "The VES KM: a pathway for protein folding in vivo". Pure and Applied Chemistry 92, n. 1 (28 gennaio 2020): 179–91. http://dx.doi.org/10.1515/pac-2019-0301.
Abstract (sommario):
AbstractWhile according to the thermodynamic hypothesis, protein folding reproducibility is ensured by the assumption that the native state corresponds to the minimum of the free energy in normal cellular conditions, here, the VES kinetic mechanism for folding in vivo is described according to which the nascent chain of all proteins is helical and the first and structure defining step in the folding pathway is the bending of that initial helix around a particular amino acid site. Molecular dynamics simulations are presented which indicate both the viability of this mechanism for folding and its limitations in the presence of a Markovian thermal bath. An analysis of a set of protein structures formed only of helices and loops suggests that bending sites are correlated with regions bounded, on the N-side, by positively charged amino acids like Lysine and Histidine and on the C-side by negatively charged amino acids like Aspartic acid.
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Liu, Chien-Ting, e George A. Brooks. "Mild heat stress induces mitochondrial biogenesis in C2C12 myotubes". Journal of Applied Physiology 112, n. 3 (1 febbraio 2012): 354–61. http://dx.doi.org/10.1152/japplphysiol.00989.2011.
Abstract (sommario):
During endurance exercise, most (≈75%) of the energy derived from the oxidation of metabolic fuels and ATP hydrolysis of muscle contraction is liberated as heat, the accumulation of which leads to an increase in body temperature. For example, the temperature of exercising muscles can rise to 40°C. Although severe heat injury can be deleterious, several beneficial effects of mild heat stress (HS), such as the improvement of insulin sensitivity in patients with type 2 diabetes, have been reported. However, among all cellular events induced by mild HS from physical activities, the direct effects and mechanisms of mild HS on mitochondrial biogenesis in skeletal muscle are least characterized. AMP-activated protein kinase (AMPK) and sirtuin 1 (SIRT1) are key energy-sensing molecules regulating mitochondrial biogenesis. In C2C12 myotubes, we found that 1 h mild HS at 40°C upregulated both AMPK activity and SIRT1 expression, as well as increased the expression of several mitochondrial biogenesis regulatory genes including peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α) and transcription factors involved in mitochondrial biogenesis. In particular, PGC-1α expression was found to be transcriptionally regulated by mild HS. Additionally, after repeated mild HS for 5 days, protein levels of PGC-1α and several mitochondrial oxidative phosphorylation subunits were also upregulated. Repeated mild HS also significantly increased mitochondrial DNA copy number. In conclusion, these data show that mild HS is sufficient to induce mitochondrial biogenesis in C2C12 myotubes. Temperature-induced mitochondrial biogenesis correlates with activation of the AMPK-SIRT1-PGC-1α pathway. Therefore, it is possible that muscle heat production during exercise plays a role in mitochondrial biogenesis.
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Thörn, Carolina Wilnerzon, Vasilios Kafetzopoulos e Bernat Kocsis. "Differential Effect of Dopamine D4 Receptor Activation on Low-Frequency Oscillations in the Prefrontal Cortex and Hippocampus May Bias the Bidirectional Prefrontal–Hippocampal Coupling". International Journal of Molecular Sciences 23, n. 19 (3 ottobre 2022): 11705. http://dx.doi.org/10.3390/ijms231911705.
Abstract (sommario):
Dopamine D4 receptor (D4R) mechanisms are implicated in psychiatric diseases characterized by cognitive deficits, including schizophrenia, ADHD, and autism. The cellular mechanisms are poorly understood, but impaired neuronal synchronization in cortical networks was proposed to contribute to these deficits. In animal experiments, D4R activation was shown to generate aberrant increased gamma oscillations and to reduce performance on cognitive tasks requiring functional prefrontal cortex (PFC) and hippocampus (HPC) networks. While fast oscillations in the gamma range are important for local synchronization within neuronal ensembles, long-range synchronization between distant structures is achieved by slow rhythms in the delta, theta, alpha ranges. The characteristics of slow oscillations vary between structures during cognitive tasks. HPC activity is dominated by theta rhythm, whereas PFC generates unique oscillations in the 2–4 Hz range. In order to investigate the role of D4R on slow rhythms, cortical activity was recorded in rats under urethane anesthesia in which slow oscillations can be elicited in a controlled manner without behavioral confounds, by electrical stimulation of the brainstem reticular formation. The local field potential segments during stimulations were extracted and subjected to fast Fourier transform to obtain power density spectra. The selective D4R agonist A-412997 (5 and 10 mg/kg) and antagonists L-745870 (5 and 10 mg/kg) were injected systemically and the peak power in the two frequency ranges were compared before and after the injection. We found that D4R compounds significantly changed the activity of both HPC and PFC, but the direction of the effect was opposite in the two structures. D4R agonist enhanced PFC slow rhythm (delta, 2–4 Hz) and suppressed HPC theta, whereas the antagonist had an opposite effect. Analogous changes of the two slow rhythms were also found in the thalamic nucleus reuniens, which has connections to both forebrain structures. Slow oscillations play a key role in interregional cortical coupling; delta and theta oscillations were shown in particular, to entrain neuronal firing and to modulate gamma activity in interconnected forebrain structures with a relative HPC theta dominance over PFC. Thus, the results of this study indicate that D4R activation may introduce an abnormal bias in the bidirectional PFC–HPC coupling which can be reversed by D4R antagonists.
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Hauck, Fabian, Thomas Magg, Ana Krolo, Ivan Bilic, Tatjana Hirschmugl, Martin Laass, Angela Rösen-Wolff, Hella Luksch, Kaan Boztug e Joachim Roesler. "Variant PIK3R1 Hypermorphic Mutation and Clinical Phenotypes in a Family with Short Statures, Mild Immunodeficiency and Lymphoma". Klinische Pädiatrie 229, n. 03 (maggio 2017): 113–17. http://dx.doi.org/10.1055/s-0043-104218.
Abstract (sommario):
Abstract Background Heterozygous point mutations in the GT splice donor consensus sequence of exon 11 of the PIK3R1 gene (coding for p85α, p55α, and p50α regulatory subunits of PI3K) lead to exon skipping and thereby to an aberrant protein that leaves PI3K hyperactivated. Several patients with this particular variant of PI3 kinase delta syndrome (APDS) suffering from sinopulmonary infections and lymphoproliferation have been described. Methods (Whole exome) sequencing, evaluation of cellular and clinical phenotypes. Results We here report a family with a new heterozygous mutation in this gene, a 9 bp deletion (c.1418_1425+1del) that, however, leads to the same skipping of exon 11. The clinical phenotypes of their members partly overlap features of patients of other reports. Conclusions We found a new mutation in PIK3R1 and show how broad the resulting clinical spectrum can be.
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Molonia, Maria Sofia, Claudia Muscarà, Antonio Speciale, Federica Lina Salamone, Giovanni Toscano, Antonella Saija e Francesco Cimino. "The p-Phthalates Terephthalic Acid and Dimethyl Terephthalate Used in the Manufacture of PET Induce In Vitro Adipocytes Dysfunction by Altering Adipogenesis and Thermogenesis Mechanisms". Molecules 27, n. 21 (7 novembre 2022): 7645. http://dx.doi.org/10.3390/molecules27217645.
Abstract (sommario):
Public health concerns associated with the potential leaching of substances from Polyethylene terephthalate (PET) packaging have been raised due to the role of phthalates as endocrine-disrupting chemicals or obesogens. In particular, changes in the environment such as pH, temperature, and irradiation can improve contaminant migration from PET food packaging. In this study, the in vitro effects of p-phthalates terephthalic acid (TPA) and dimethyl terephthalate (DMT) on murine adipocytes (3T3-L1) were evaluated using concentrations that might be obtained in adult humans exposed to contaminated sources. TPA and, in particular, DMT exposure during 3T3-L1 differentiation increased the cellular lipid content and induced adipogenic markers PPAR-γ, C/EBPß, FABP4, and FASN, starting from low nanomolar concentrations. Interestingly, the adipogenic action of TPA- and DMT-induced PPAR-γ was reverted by ICI 182,780, a specific antagonist of the estrogen receptor. Furthermore, TPA and DMT affected adipocytes’ thermogenic program, reducing pAMPK and PGC-1α levels, and induced the NF-κB proinflammatory pathway. Given the observed effects of biologically relevant chronic concentrations of these p-phthalates and taking into account humans’ close and constant contact with plastics, it seems appropriate that ascertaining safe levels of TPA and DMT exposure is considered a high priority.
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Marinkovic, Dragan, Xin Zhang, Carlo Brugnara e Saghi Ghaffari. "Foxo3 Transcription Factor Regulates Oxidative Stress in In Vivo Erythropoiesis." Blood 108, n. 11 (16 novembre 2006): 468. http://dx.doi.org/10.1182/blood.v108.11.468.468.
Abstract (sommario):
Abstract Reactive oxygen species (ROS) such as superoxide anions and hydrogen peroxides are byproducts of normal oxidative metabolism that play an important role in regulating the proliferation of many cell types including hematopoietic cells. However, excess production of ROS induces damage to cellular components including DNA, maintains cellular transformation, apoptosis and senescence, and is associated with leukemias. Therefore highly regulated mechanisms are required for balancing ROS production during normal hematopoiesis. In particular, erythroid cells require an efficient scavenging mechanism for ROS because of high exposure to oxidative stress as a result of an abundance of heme iron. Specifically, deficiencies in erythroid ROS scavenging enzymes are associated with malignancies and other hematopoietic disorders such as sideroblastic anemia. We have recently shown that Erythropoietin (Epo)-induced activation of the PI3-kinase/AKT signaling pathway supports differentiation and maturation of primary erythroid progenitor cells (Zhao et al., Blood 2006; Ghaffari et al., Blood 2006). FOXO forkhead transcription factors constitute one of downstream targets of the PI3-kinase/AKT signaling pathway. In response to Epo, activation of PI3-kinase/AKT signaling pathway results in rapid phosphorylation of FOXO proteins triggering its translocation to the cytosol where, away from their transcriptional targets, FOXO are inhibited. FOXO proteins play many fundamental functions including protecting cells against oxidative insults by controlling the expression of ROS scavenging enzymes manganese superoxide dismutase and catalase. Here we show that Foxo3 is the most abundant FOXO protein in erythroid cells whose expression is upregulated several fold during maturation of mouse primary fetal liver erythroid progenitor cells. Using immunofluorescent staining and reporter gene assay, we show that Foxo3 enters the nucleus and becomes transcriptionally active as fetal liver erythroblasts mature. Notably, Foxo3 activation is concomitant with downregulation of Epo receptor (EpoR) on maturing erythroblasts. We further demonstrate that Foxo3 regulates levels of ROS in adult erythroid cells. In particular, eight to twelve week old Foxo3-deficient mice (kindly provided by Dr. Ron DePinho, Harvard Medical School) exhibit hemolysis that is responsive to in vivo therapy by N-Acetyl- l-Cysteine, a generic scavenger of ROS, suggesting that Foxo3−/ − hemolysis is induced by ROS. In addition, Foxo3−/ − hemolysis is characterized by enhanced concentration of erythroid ROS as determined by dichlorofluorescein assay and significantly decreased expression of ROS scavenging enzymes, leading to protein oxidation and shortened erythrocyte lifespan. In agreement with these results, Foxo3−/ − mice are highly sensitive to oxidative stress and, in contrast to their wild type counterparts, do not survive treatment with phenylhydrazine which reacts with hemoglobin to generate ROS. These results demonstrate that Foxo3 is required for protecting erythroid cells from oxidative stress. Finally, our data further support an important function for Foxo3 in coordinating cell cycle and differentiation of primary erythroblasts that is mediated by a ROS-regulated mechanism. Collectively, these findings establish Foxo3, a transcription factor targeted by EpoR signaling, as a regulator of oxidative stress in primary erythropoiesis.
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Becker, M., P. Koelink, C. Buskens e M. Wildenberg. "P126 Differential granulocyte populations as therapeutic targets in fistula". Journal of Crohn's and Colitis 18, Supplement_1 (1 gennaio 2024): i419. http://dx.doi.org/10.1093/ecco-jcc/jjad212.0256.
Abstract (sommario):
Abstract Background Despite the recent increase in therapeutic options in IBD care, treatment of perianal disease and in particular fistula remains highly challenging. Specific targeted medical therapy is not currently available, and a majority of patients fails to respond to surgical intervention. In contrast, cryptoglandular fistula show much higher response rates with closure in up to 80-90% of patients. Interestingly, the most present cell type in fistula, the granulocyte, is also the least studied due to their fragile nature. To fill this void, we evaluated granulocytes in perianal fistula and those present in the blood. Methods Curettage material of 18 fistula (Crohn n=15 and cryptoglandular n=5) was obtained and processed by mass cytometry. Two additional samples were obtained (1 Crohn, 1 cryptoglandular) together with matching blood samples and assessed by single cell RNASeq. Results As expected, granulocytes formed the majority of all cells in all fistula (mean 64%). Cryptoglandular fistula displayed significantly more granulocytes than Crohn’s related fistula. Single cell analysis showed 4 subsets: Subset 1 was the main subset in blood, and expressed high levels of LAMTOR4. Interestingly, although found both in blood and fistula, abundance was much higher in blood (80 vs 10%) and signaling cascades differed. In blood, activity was associated with degranulation, IL8 activity and migration. In fistula, a very strong IFNa/b signature was present. Subset 2 expressed high MMP9, and showed degranulating activity. Subsets 3 and 4 were almost exclusively found in the fistula tracts, and were defined by expression of PI3 and LRG1 respectively. Pathway analysis showed the PI3+ population to have strong cytokine signaling but little degranulating or migratory activity. Conversely, the LRG1+ population showed little cytokine activity, but stronger degranulating activity and integrin signaling. The two populations also expressed distinctive chemokine receptors, with PI3+ cells expressing high levels of CXCR4, while LRG1+ express CXC1 and CXCR2, suggesting differntial recruiment and potential modulation. In that light, it is interesting to note the proportion of PI3+ and LRG1+ cells differed between patients, with the majority of Crohn derived cells being PI3+ while the cryptoglandular fistula mainly contained LRG1+ cells. Conclusion Granulocytes form the main cellular component of fistula tracts in both Crohn and cryptoglandular fistula. Four different subsets of granulocytes could be identified, of which the two main subtypes in fistula tracts appear to differ significantly both in phenotype, activity and method of recruitment. This data may be a starting point for specific interventions in this highly abundant but often overlooked cell type.
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Fuchikami, Kinji, Hiroko Togame, Atsuko Sagara, Tomoko Satoh, Florian Gantner, Kevin B. Bacon e Peter Reinemer. "A Versatile High-Throughput Screen for Inhibitors of Lipid Kinase Activity: Development of an Immobilized Phospholipid Plate Assay for Phosphoinositide 3-Kinase γ". Journal of Biomolecular Screening 7, n. 5 (ottobre 2002): 441–50. http://dx.doi.org/10.1177/108705702237676.
Abstract (sommario):
The family of phosphoinositide 3-kinases (PI3K) regulates fundamental cellular responses such as proliferation, apoptosis, motility, and adhesion. In particular, the PI3K γ isoform plays a critical role in the control of cell migration. Despite the attractiveness of PI3-kinases as drug targets, drug discovery efforts have been hampered by the lack of appropriate lipid kinase assay formats suitable for high-throughput screening. The authors report the development of a simple and robust 384-well plate assay that is based on33 P-phosphate transfer from radiolabeled [γ33 P]ATP to phosphatidylinositol immobilized on Maxisorp™ plates. The established assay format for PI3K γ was easily adapted to the automated screening platform and was successfully employed for high-throughput screening. Enzymatic and inhibition characteristics of recombinant human PI3K γ determined with the plate assay are in very good agreement with previously reported values determined in other assay formats. Maximal catalytic activity of PI3K γ was observed at pH 7.0. The apparent Km value for ATP using a 1:1 mixture of phosphatidylinositol and phosphatidylserine was determined to be 7.3μM (6.0-8.6 μM, 95% confidence interval [CI]). IC50 values for known PI3-kinase inhibitors were determined to be 1.45 nM (1.17-1.80 nM, 95% CI) for wortmannin and estimated from partial inhibition data to be 1400, 2830, and 21,400 nM for quercetin, LY294002, and staurosporine, respectively. This novel assay approach allows for screening of inhibitors of lipid kinases in high-throughput mode and thereby may facilitate the identification of novel inhibitory structures for drug development.
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Rao, Srinivas G., Graham V. Williams e Patricia S. Goldman-Rakic. "Isodirectional Tuning of Adjacent Interneurons and Pyramidal Cells During Working Memory: Evidence for Microcolumnar Organization in PFC". Journal of Neurophysiology 81, n. 4 (1 aprile 1999): 1903–16. http://dx.doi.org/10.1152/jn.1999.81.4.1903.
Abstract (sommario):
Isodirectional tuning of adjacent interneurons and pyramidal cells during working memory: evidence for microcolumnar organization in PFC. Studies on the cellular mechanisms of working memory demonstrated that neurons in dorsolateral prefrontal cortex (dPFC) exhibit directionally tuned activity during an oculomotor delayed response. To determine the particular contributions of pyramidal cells and interneurons to spatial tuning in dPFC, we examined both individually and in pairs the tuning properties of regular-spiking (RS) and fast-spiking (FS) units that represent putative pyramidal cells and interneurons, respectively. Our main finding is that FS units possess spatially tuned sensory, motor, and delay activity (i.e., “memory fields”) similar to those found in RS units. Furthermore, when recorded simultaneously at the same site, the majority of neighboring neurons, whether FS or RS, displayed isodirectional tuning, i.e., they shared very similar tuning angles for the sensory and delay phases of the task. As the trial entered the response phase of the task, many FS units shifted their direction of tuning and became cross-directional to adjacent RS units by the end of the trial. These results establish that a large part of inhibition in prefrontal cortex is spatially oriented rather than being untuned and simply regulating the threshold response of pyramidal cell output. Moreover, the isodirectional tuning between adjacent neurons supports a functional microcolumnar organization in dPFC for spatial memory fields similar to that found in other areas of cortex for sensory receptive fields.
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Wygrecka, Malgorzata, Philipp Markart, Clemens Ruppert, Tim Kuchenbuch, Ludger Fink, Rainer Bohle, Friedrich Grimminger, Werner Seeger e Andreas Günther. "Compartment- and cell-specific expression of coagulation and fibrinolysis factors in the murine lung undergoing inhalational versus intravenous endotoxin application". Thrombosis and Haemostasis 92, n. 09 (2004): 529–40. http://dx.doi.org/10.1160/th04-02-0126.
Abstract (sommario):
SummaryIntraalveolar and intravascular fibrin formation are typical hallmarks of acute inflammatory lung diseases, and may foster subsequent fibroproliferative events.We investigated the regulation and cellular sources of key coagulation and fibrinolysis factors in lungs undergoing compartmentalized challenge with endotoxin (LPS). BALB/c mice received 15ng LPS either by intravenous injection or by inhalation. Quantitative gene expression analysis (real-time RT-PCR) was performed for tissue factor (TF),TF pathway inhibitor (TFPI), tissue-type plasminogen activator (t-PA), urokinase-type-PA (u-PA), PA inhibitor-1 (PAI-1), and PAI-2 in peripheral white blood cells (PBC) as well as in alveolar macrophages (AM), type-II pneumocytes (ATII), endothelial cells (EC) and smooth muscle cells (SMC), all obtained by laser microdissection. Neither route of LPS administration caused substantial protein leakage or leukocyte recruitment into the alveolar space. Compartmentalized upregulation of procoagulant and downregulation of fibrinolytic activities was, however, observed in response to both modes of LPS challenge. Intraalveolar endotoxin, in particular, caused strong upregulation of TF (∼ 20-fold increase in gene expression) and PAI-2 (225-fold increase) in microdissected AM, upregulation of PAI-1 in microdissected ATII (300-fold increase) and EC (180-fold increase), upregulation of t-PA in EC (40-fold), and downregulation of u-PA in vascular smooth muscle cells. TFPI was largely unchanged in all cell types, and PBC showed no major gene regulatory response to inhaled endotoxin. We conclude that the lung possesses a cell-specific alveolar coagulation and fibrinolysis system, being independent of the vascular coagulation cascade and responding readily with enhanced procoagulant and anti-fibrinolytic activities to LPS challenge.
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Santamaría-Gómez, Javier, Miguel Ángel Rubio, Rocío López-Igual, Ana B. Romero-Losada, Fernando M. Delgado-Chaves, Roque Bru-Martínez, Francisco J. Romero-Campero et al. "Role of a cryptic tRNA gene operon in survival under translational stress". Nucleic Acids Research 49, n. 15 (11 agosto 2021): 8757–76. http://dx.doi.org/10.1093/nar/gkab661.
Abstract (sommario):
Abstract As compared to eukaryotes, bacteria have a reduced tRNA gene set encoding between 30 and 220 tRNAs. Although in most bacterial phyla tRNA genes are dispersed in the genome, many species from distinct phyla also show genes forming arrays. Here, we show that two types of arrays with distinct evolutionary origins exist. This work focuses on long tRNA gene arrays (L-arrays) that encompass up to 43 genes, which disseminate by horizontal gene transfer and contribute supernumerary tRNA genes to the host. Although in the few cases previously studied these arrays were reported to be poorly transcribed, here we show that the L-array of the model cyanobacterium Anabaena sp. PCC 7120, encoding 23 functional tRNAs, is largely induced upon impairment of the translation machinery. The cellular response to this challenge involves a global reprogramming of the transcriptome in two phases. tRNAs encoded in the array are induced in the second phase of the response, directly contributing to cell survival. Results presented here show that in some bacteria the tRNA gene set may be partitioned between a housekeeping subset, which constantly sustains translation, and an inducible subset that is generally silent but can provide functionality under particular conditions.
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Konechnyi, Yulian, Oksana Hrushka, Hanna Pryzyhley, Roksolana Konechna, Andrii Lozynskyi, Olena Korniychuk e Roman Lesyk. "Cell immunity of laboratory animals under the influence of 5-indolylmethylene rhodanine-3-carboxylic/sulphonic acid derivative". ScienceRise: Pharmaceutical Science, n. 1 (29) (27 febbraio 2021): 76–81. http://dx.doi.org/10.15587/2519-4852.2021.224328.
Abstract (sommario):
The aim. To study the cell immunity status under influence of 3-[5-(1H-indol-3-ylmethylene)-4-oxo-2-thioxo-thiazolidin-3-yl]-propionic acid, as a prominent 4-thiazolidinone derivative and a class of biologically active compounds with polypharmacological properties. Materials and methods. Experimental method on the model of laboratory animals (guinea pigs); intradermal allergy tests; relative and absolute content in the peripheral blood of T- and B-lymphocytes subpopulations; hematological indexies: index of the ratio of lymphocytes and monocytes, index of the ratio of neutrophils and monocytes, index of the ratio of neutrophils and eosinophils, phagocytic index, phagocytic number; ELISA; organic synthesis; pharmacological screening. Results. The effect of 3-[5-(1H-indol-3-ylmethylene)-4-oxo-2-thioxo-thiazolidin-3-yl]-propionic acid has antifungal properties and affect cellular component of immunity in vivo in the guinea pigs model. There are no changes in the skin of guinea pigs during and after chemical applications of the skin and after intradermal tests. The compound stimulate the immune cells, in particular the lymphocyte (increase in the absolute number of CD3 T-lymphocytes by 21.46 % and the absolute number of CD8 T-suppressors by 27.15 %), but with a selective inhibitory effect on certain units (decrease the relative number of NK cells CD16 by 11.57 % and B-lymphocytes CD22 by 23.08 %). There was an increase in the activity of the macrophage phagocytic system (increase in PN by 439.87 % and PI by 62.73 % at 120 minutes), which indicates the reliability of the absorbing function of phagocytes, but with a decrease in their ability to endocytosis (PCI decreased significantly by 78,72 %). Conclusions. Synthesized 3-[5-(1H-indol-3-ylmethylene)-4-oxo-2-thioxo-thiazolidin-3-yl]-propionic acid has a selective activating effect on certain parts of cellular immunity and on phagocytic activity. Derivate influence on the phagocytic activity of neutrophils is ambiguous, and the effect of the compound directed to the cellular part of the immune system does not cause cellular immunodeficiency. The studied derivative is promising for further study of the drug-like molecule with antifungal and antitumor effects
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Summerfield, Tina C., Sowmya Nagarajan e Louis A. Sherman. "Gene expression under low-oxygen conditions in the cyanobacterium Synechocystis sp. PCC 6803 demonstrates Hik31-dependent and -independent responses". Microbiology 157, n. 2 (1 febbraio 2011): 301–12. http://dx.doi.org/10.1099/mic.0.041053-0.
Abstract (sommario):
We have investigated the response of the cyanobacterium Synechocystis sp. PCC 6803 during growth at very low O2 concentration (bubbled with 99.9 % N2/0.1 % CO2). Significant transcriptional changes upon low-O2 incubation included upregulation of a cluster of genes that contained psbA1 and an operon that includes a gene encoding the two-component regulatory histidine kinase, Hik31. This regulatory cluster is of particular interest, since there are virtually identical copies on both the chromosome and plasmid pSYSX. We used a knockout mutant lacking the chromosomal copy of hik31 and studied differential transcription during the aerobic–low-O2 transition in this ΔHik31 strain and the wild-type. We observed two distinct responses to this transition, one Hik31 dependent, the other Hik31 independent. The Hik31-independent responses included the psbA1 induction and genes involved in chlorophyll biosynthesis. In addition, there were changes in a number of genes that may be involved in assembling or stabilizing photosystem (PS)II, and the hox operon and the LexA-like protein (Sll1626) were upregulated during low-O2 growth. This family of responses mostly focused on PSII and overall redox control. There was also a large set of genes that responded differently in the absence of the chromosomal Hik31. In the vast majority of these cases, Hik31 functioned as a repressor and transcription was enhanced when Hik31 was deleted. Genes in this category encoded both core and peripheral proteins for PSI and PSII, the main phycobilisome proteins, chaperones, the ATP synthase cluster and virtually all of the ribosomal proteins. These findings, coupled with the fact that ΔHik31 grew better than the wild-type under low-O2 conditions, suggested that Hik31 helps to regulate growth and overall cellular homeostasis. We detected changes in the transcription of other regulatory genes that may compensate for the loss of Hik31. We conclude that Hik31 regulates an important series of genes that relate to energy production and growth and that help to determine how Synechocystis responds to changes in O2 conditions.
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Arsentieva, N. A., N. E. Liubimova, O. K. Batsunov, Z. R. Korobova, O. V. Stanevich, A. A. Lebedeva, E. A. Vorobyov et al. "Plasma cytokines in patients with COVID-19 during acute phase of the disease and following complete recovery". Medical Immunology (Russia) 23, n. 2 (3 maggio 2021): 311–26. http://dx.doi.org/10.15789/1563-0625-pci-2312.
Abstract (sommario):
COVID-19, an infection caused by the new coronavirus SARS-CoV-2, is associated with a number of pathophysiological mechanisms, mobilizing a wide spectrum of biomolecules, mainly, cytokines.The purpose of this study was to evaluate levels of multiple cytokines in blood plasma from the patients with COVID-19 during acute phase of the disease, and upon complete recovery. Samples of peripheral blood plasma of 56 patients with COVID-19, 69 convalescents and 10 healthy individuals were examined. Concentrations of 46 molecules, such as IL-1α, IL-1β, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-9, IL-12 (p40), IL-12 (p70), IL-13, IL-15, IL-17A/CTLA8, IL-17-E/IL-25, IL-17F, IL-18, IL-22, IL-27, IFNα2, IFNγ, TNFα, TNFβ/ Lymphotoxin-α (LTA), CCL2/MCP-1, CCL3/MIP-1α, CCL4/MIP-1β, CCL7/MCP-3, CCL11/Eotaxin, CCL22/MDC, CXCL1/GROα, CXCL8/IL-8, CXCL9/MIG, CXCL10/IP-10, CX3CL1/Fractalkine, IL-1ra, IL-10, EGF, FGF-2/FGF-basic, Flt3 Ligand, G-CSF, M-CSF, GM-CSF, PDGF-AA, PDGF-AB/ BB, TGF-α, VEGF-A were measured via xMAP multiplexing technology. Significantly increased levels of 18 cytokines were found in blood plasma from COVID-19 patients during acute phase of the disease (as compared to control group), i.e., IL-6, IL-7, IL-15, IL-27, TNFα, TNFβ/Lymphotoxin-α (LTA), CCL2/MCP-1, CCL7/MCP-3, CXCL1/GROα, CXCL8/IL-8, CXCL10/IP-10, CXCL9/MIG, IL-1rа, IL-10, M-CSF, GM-CSF, VEGF-A. We found a significant decrease of nearly all the mentioned cytokines in recovered patients, in comparison with those who had moderate, severe/extremely severe disease. Moreover, we revealed a significantly decreased level of 8 cytokines in plasma from convalescents, as compared with control group, i.e., IL-1α, IL-2, IL-9, IL-12 p40, IL-18, CCL22/MDC, Flt3 Ligand, TGF-α. Immune response caused by SARS-CoV-2 infection involves multiple cytokines, mostly, with pro-inflammatory effects. We have shown for the first time that the convalescence phase is characterized by significantly lower levels of cytokines which regulate cellular differentiation and hematopoiesis (in particular, lymphocytes, T-cells and NK-cells). Over acute phase of the disease, the levels of these cytokines did not change. We revealed a significant decrease of most plasma cytokines upon recovery as compared to acute phase. On the contrary, acute phase of the disease is accompanied by significant increase of both pro- and antiinflammatory cytokines in blood plasma.
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Gotesman, Moran, Thanh-Trang T. Vo, Sharmila Mallya, Qi Zhang, Ce Shi, Markus Müschen, David M. Weinstock et al. "mTOR Kinase Inhibitors Enhance Efficacy of TKIs in Preclinical Models of Ph-like B-ALL". Blood 128, n. 22 (2 dicembre 2016): 2763. http://dx.doi.org/10.1182/blood.v128.22.2763.2763.
Abstract (sommario):
Abstract Background and Rationale: B-lymphoblastic leukemia (B-ALL) is the most common cancer of childhood. While event-free survival (EFS) exceeds 85% for most patients treated with contemporary therapy, outcomes are very poor for children who relapse, highlighting a need for new treatments. In particular, children with Philadelphia chromosome-like (Ph-like) B-ALL (who lack BCR-ABL1 rearrangement) have high rates of relapse and mortality with conventional chemotherapy. Transcriptional profiling and genomic sequencing of Ph-like ALL specimens have identified a variety of alterations that activate oncogenic kinase signaling, including rearrangements (R) of CRLF2, ABL1, and PDGFRB. Addition of the tyrosine kinase inhibitor (TKI) imatinib to chemotherapy has dramatically improved EFS for patients with BCR-ABL1-rearranged (Ph+) B-ALL, and it is hypothesized that TKI addition to therapy will similarly improve outcomes for patients with Ph-like ALL. Our prior preclinical studies in Ph+ B-ALL demonstrated enhanced efficacy of combining TKIs (imatinib or dasatinib) with mTOR kinase inhibitors (TOR-KIs) (Janes et al., Nature Medicine 2010; Janes et al, Leukemia2013). In the current studies, we hypothesized that dual kinase inhibitor therapy would have superior anti-leukemia cytotoxicity in Ph-like ALL and thus investigated combined TKI and TOR-KI treatment using patient-derived xenograft (PDX) models of childhood Ph-like ALL. Methods: For in vitro studies, viably cryopreserved leukemia cells from established ABL1-R Ph-like ALL PDX models (2 ETV6-ABL1) were incubated with the TKI dasatinib, TOR-KIs, or both TKI + TOR-KI for 72 hours prior to flow cytometric assessment of cellular viability via Annexin V and propidium iodide staining. Two chemically distinct TOR-KIs (MLN0128 or AZD2014) were used to confirm on-target effects. Additional primary ABL1-R or PDGFRB-R Ph-like ALL specimens were plated in methylcellulose without or with inhibitors in colony-forming assays. Phosphoflow cytometry (PFC) analysis of ALL cells incubated with inhibitors was also performed to measure the ability of TKIs and TOR-KIs to inhibit intracellular ABL1 and PI3K/mTOR signaling pathways. For in vivo studies, Ph-like ALL PDX models were treated with dasatinib, the TOR-KI AZD8055, or both drugs via daily oral gavage for 8 days. Human CD19+ ALL was quantified in murine spleens and bone marrow at end of treatment with quantification of cycling cells by EdU incorporation. PFC analysis of murine bone marrow was also performed 2 hours after drugs were dosed, to measure in vivo inhibition of signaling proteins. Results: Combined in vitro treatment with dasatinib and MLN0128 or AZD2014 decreased cellular viability more than inhibitor monotherapy. Similarly, in a set of CRLF2-rearranged samples, mTOR inhibitors augmented killing by the JAK2 inhibitor BBT-594. Incubation of primary ABL1-R or PDGFRB-R ALL cells with both dasatinib and AZD2014 more robustly inhibited colony formation than did inhibitor monotherapy. In in vitro PFC analyses of ABL1-R samples, we observed expected dasatinib-induced inhibition of phosphorylated (p) STAT5. Inhibition of the mTOR substrate pS6 was observed with dasatinib, MLN0128, and AZD2014 with more complete inhibition achieved when dasatinib combined with either MLN0128 or AZD2014. Similarly, in vivo treatment of PDX models with dasatinib and AZD8055 reduced leukemia burden and pS6 signaling more completely than either inhibitor alone. Importantly, dual inhibition decreased the percentage of cycling human ALL cells in murine bone marrow, but preserved cycling in normal mouse bone marrow cells in the same animals. Our data thus provide additional compelling preclinical rationale for combined inhibitor therapy with TKIs and TOR-KIs in Ph-like ALL. Disclosures Weinstock: Novartis: Consultancy, Research Funding. Mullighan:Incyte: Membership on an entity's Board of Directors or advisory committees; Amgen: Speakers Bureau; Loxo Oncology: Research Funding. Konopleva:Reata Pharmaceuticals: Equity Ownership; Abbvie: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; Stemline: Consultancy, Research Funding; Eli Lilly: Research Funding; Cellectis: Research Funding; Calithera: Research Funding.
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Adeluola, Adeoluwa A., e A. R. M. Ruhul Amin. "Abstract 3245: Genes associated with Src-Met driven resistance of head & neck cancers to EGFR-PI3K cotargeting". Cancer Research 82, n. 12_Supplement (15 giugno 2022): 3245. http://dx.doi.org/10.1158/1538-7445.am2022-3245.
Abstract (sommario):
Abstract Background: In recent years, oncology research has led to the discovery of targeted therapies aimed at specific genetic abnormalities unique to cancer cells. In particular, the overexpression of epidermal growth factor receptor (EGFR) and constitutive activation of the phosphoinositide-3-kinase/protein kinase B (PI3K/AKT) pathway are common aberrations in head and neck cancer. However, intrinsic and acquired resistance are continuously posing challenges to success. Previously, we reported that the combination of EGFR inhibitor erlotinib with PI3K inhibitor BKM120 had synergistic effects that induced efficient apoptosis in a panel of head and neck cancer cell lines, but some cells were still resistant. The purpose of the current study is to understand the mechanism of resistance to EGFR and PI3-K co-targeting. Hypothesis: Src-Met signaling confers apoptosis resistance to EGFR and PI3K cotargeting by regulating downstream genes expresiion. Methods: Apoptosis was measured by annexin V-PE staining. Western blotting and qPCR were used for measuring the expression of proteins and mRNA, respectively. RNASeq was conducted from RNA samples treated with (Erlotinib + BKM120) ± dasatinib (Src inhibitor)/crizotinib(Met inhibitor). Results: Biochemical studies revealed that JHU022 cells, which were resistant to the combination treatment, had an overactivation of c-Met receptor tyrosine kinase that was regulated by Src kinases. Pharmacological or genetic inactivation of both Met or Src kinase sensitized this cell line to apoptosis induced by EGFR and PI3K co-targeting. RNA-Seq analysis identified that a total of 291 genes were modulated (2-folds) by both crizotinib and dasatinib. Pathway enrichment suggested that many of these genes were associated with cell cycle, DNA replication, and cellular response to DNA damage. CPA4 was identified as the most downregulated gene and GDF15 as one of the top upregulated genes. Conclusions: SRC-Met signaling confers resistant to EGFR and PI3K cotargeting by modulating genes associated with cell cycle, DNA replication, and cellular response to DNA damage. Citation Format: Adeoluwa A. Adeluola, A.R.M. Ruhul Amin. Genes associated with Src-Met driven resistance of head & neck cancers to EGFR-PI3K cotargeting [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3245.
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Herko, Amanda, Cory Mavis, Myron S. Czuczman e Francisco Hernandez. "AMG 319, a Novel Inhibitor of Phosphoinositide-3 Kinase Delta (PI3Kd), Demonstrates Activity in Lymphoma Pre-Clinical Models". Blood 120, n. 21 (16 novembre 2012): 3718. http://dx.doi.org/10.1182/blood.v120.21.3718.3718.
Abstract (sommario):
Abstract Abstract 3718 The PI3k/AKT/mTOR signaling pathway has been found to be deregulated in patients with various subtypes of B-cell lymphoma including mantle cell lymphoma (MCL) and diffuse large B-cell lymphoma (DLBCL). Targeting this particular pathway has been evaluated in multiple pre-clinical models and clinical trials using pharmacological inhibitors with variable degrees of success. More selective and potent PI3K inhibitors, such as AMG 319 are being developed and need proper evaluation in currently relevant pre-clinical models (i.e. rituximab resistant models). To this end, we evaluated the activity of AMG 319 as a single agent or in combination with monoclonal antibodies, targeted agents and chemotherapy drugs in a panel of rituximab-sensitive (RSCL), rituximab-resistant cell lines (RRCL) and primary lymphoma cells isolated from patients with treatment naïve or relapsed/refractory (rel/ref) B- and T-cell lymphoma. Furthermore, we attempted to characterize the cell death pathways executed following in vitro exposure to AMG 319. RSCL, RRCL, T-cell lymphoma, Hodgkin's lymphoma (HL) and MCL cell lines were exposed to escalating doses of AMG 319 (0.1 to 100μM). Isolated primary lymphoma cells were exposed to lower doses of AMG 319 (1 and 10μM) as a single agent and in combination with bortezomib (BTZ) (5–10nM). Cell viability was determined utilizing presto blue and cell titer glo assays. 51Cr release studies were conducted to assess the effect of AMG 319 in rituximab or ofatumumab immunological activity. Lymphoma cell lines were exposed to AMG 319 (10μM) or DMSO (0.1%) for 48 hours. Subsequently cells were labeled with 51Cr and exposed to rituximab, ofatumumab or isotype control with human serum (25%) or effector cells isolated from healthy donors (effector/target ratio 40/1). Finally, to characterize the contribution of the intrinsic apoptotic pathway to AMG 319 activity, primary tumor cells isolated from lymphoma patients were exposed to AMG 319 with or without a pan-caspase inhibitor (Q-VD-Oph, 5μM) and changes in cell viability were detected. AMG 319 exhibited dose-dependant activity as a single agent against various cell lines including RSCL, RRCL, MCL and T-cell lymphoma cell lines. In addition, AMG 319 induced cell death in primary tumor cells (N=5) at lower doses than in cell lines. Preliminary experiments suggest a synergistic activity when AMG 319 is combined with BTZ in vitro, although further analysis is required with a larger number of primary tumor cell samples. Pre-exposure of one RRCL and one RSCL to AMG 319 enhanced the biological activity of rituximab and ofatumumab in terms of antibody dependent cellular cytotoxicity (ADCC) or complement mediated cytotoxicity (CMC), and further investigations with additional cell lines are ongoing. Finally, caspase inhibition diminished AMG 319 activity in primary tumor cells in vitro, suggesting that induction of apoptosis via the mitochondrial pathway plays a role in its anti-tumor activity. Our data suggests that AMG 319 as a single agent is active against NHL cells and potentiate the anti-tumor activity of BTZ and to a lesser degree monoclonal antibodies targeting CD20 antigen. Ongoing studies are aimed to evaluate AMG 319 in combination with chemotherapy agents in order to better optimize the activity of this novel PI3 kinase delta inhibitor in B-cell and T-cell lymphomas. Disclosures: No relevant conflicts of interest to declare.
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Schwarzer, Adrian, Helmut Holtmann, Celina Schauerte, Nomme Benn, Jan Völkel, Sabine Knöß, Johannes Zuber, Zhixiong Li, Axel Schambach e Christopher Baum. "Investigating Synthetic Lethality Between mTOR Hyperactivation and Cap-Dependent mRNA Translation In a Receptor Tyrosine Kinase Driven Model Of Acute T-Cell Leukemia". Blood 122, n. 21 (15 novembre 2013): 3913. http://dx.doi.org/10.1182/blood.v122.21.3913.3913.
Abstract (sommario):
Abstract T-cell acute lymphoblastic leukemia (T-ALL) remains a therapeutic challenge. In particular, relapsed disease is refractory to further therapy and has a dismal outcome. High activation of the PI3K-AKT-mTOR pathway is a hallmark of T-ALL that has been linked to the resistance of T-ALL to glucocorticoids and chemotherapy. The master regulator of PI3K-AKT signaling is PTEN. PTEN loss (1) is accompanied by an adverse outcome, (2) occurs as secondary event in T-ALL relapses and (3) is selected for after xenotransplantation of human T-ALLs into NSG mice. Interestingly, even in the absence of PTEN, the PI3-Kinases γ and δ, which link receptor tyrosine kinases (RTK) and PIP3 signaling, are critical for T-ALL formation. In lung cancer, both PTEN loss and activation of RTK signaling are required for full activation of AKT and aggressive disease. However, whereas the role of PTEN in T-ALL is well appreciated, little is known about the contribution of RTK signaling. We previously demonstrated the aberrant expression of members of the Neurotrophin receptor tyrosine kinase family (tropomyosin-related kinases - TRKA/B/C) in primary human leukemias of myeloid and lymphoid origin. We detected high expression of TRKB in several T-ALL samples. Some samples also co-expressed intracellular BDNF (brain derived neurotrophic factor), the ligand for TRKB, suggesting the existence of autocrine loops between the receptor and its ligands. Expression of the TRKB/BDNF autocrine loop or of a constitutively active form of the human TRKA receptor (ΔTrkA) in murine hematopoietic stem cells elicited T-ALL with a mean latency of 100 days in our murine transplantation model. Here we dissect the downstream signaling cascades in BDNF/TRKB or ΔTrkA induced T-ALL clones and show acquisition of activating Notch1 mutations and loss of PTEN during clonal evolution of T-ALLs induced by deregulated TRK-signaling. All three events contribute independently to activation of mTORC1 and mTORC2, demonstrating a strong selective pressure for enhanced mTOR signaling in T-ALL. To investigate the role of both mTOR complexes and downstream effectors, we used an improved Tet-regulated miR30-shRNA system in conjunction with a FACS-based reporter assay, allowing the rapid identification of shRNAs that give powerful knockdown at the single copy level. We identified several potent RNAi triggers against Rictor (mTORC2), Raptor (mTORC1) and members of the cap-initiation complex. Knockdown of Rictor or Raptor alone caused a transient decrease of proliferation and viability. In contrast, complete inhibition of mTOR with Torin1 or knockdown of eIF4E, the rate limiting subunit of the cap initiation complex, resulted in strong induction of apoptosis. This demonstrates that increased cap-dependent translation is a key effector of oncogenic mTOR in TRK+Notch+PTEN- T-ALL. Next, we investigated the efficacy of 4EGI-1E, a novel isoform of the previously described inhibitor of cap-dependent translation 4EGI-1, in this T-ALL model. 4EGI-1E induced apoptosis of T-ALL blasts in vitro with an EC50 of 3.5 mM, whereas the EC50 for global inhibition of cap-dependent translation was 50 mM, suggesting that 4EGI-1E targets a subset of mRNAs that are regulated by cap-dependent translation and are crucial for T-ALL survival. Microarray analysis of polysome fractions from DMSO and 4EGI-1E-treated cells in vitro revealed that 4EGI-1E treatment decreased the active translation of mRNAs for genes observed to be upregulated in T-ALL. These genes included members of the translational apparatus, mitochondrial matrix proteins, cyclins, c-Myc and Bcl-2. Polysome profiling in vivo recapitulated the in vitro results, showing that 4EGI-1E caused a global decrease in the ribosomal occupancy of cellular mRNAs. Network analysis suggested c-Myc as a central node within the depleted mRNAs. Abrogation of c-myc expression and induction of apoptosis were observed as soon as 4 hours after injection of 4EGI-1E (1.5 mg) into leukemia bearing animals. Depletion of T-ALL blasts from the bone marrow was achieved after 5 days of daily 4EGI-1E treatment, T-ALL (DMSO: 39% (SD 18%) vs. 4EGI-1E 0.54% (SD 0.62%) p=0.003). Finally, we investigated the effects of 4EGI-1E on healthy hematopoiesis, demonstrating the existence of a therapeutic window for inhibition of cap-dependent translation in vivo. Hence, inhibiting eIF4E is a promising approach to target c-myc in a genetically complex T-ALL model. Disclosures: No relevant conflicts of interest to declare.
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Ligon, John, Woonyoung Choi, Gady Cojocaru, Wei Fu, Emily Hsiue, Teniola Oke, Carol Morris et al. "506 The tumor immune microenvironment of metastatic osteosarcoma is marked by lymphocyte exclusion and impacts patient progression-free survival". Journal for ImmunoTherapy of Cancer 8, Suppl 3 (novembre 2020): A541—A542. http://dx.doi.org/10.1136/jitc-2020-sitc2020.0506.
Abstract (sommario):
BackgroundPatients with relapsed metastatic osteosarcoma have no effective treatments available to them,1 and immunotherapy thus far has not succeeded in improving outcomes.2–5 We aim to understand the immune architecture of the tumor microenvironment (TME) of osteosarcoma, with the goal of harnessing the immune system as a major therapeutic strategy for the treatment of patients with osteosarcoma.Methods66 osteosarcoma tissue specimens were stained and analyzed by immunohistochemistry. Tumor-infiltrating lymphocytes (TILs) from 25 specimens were profiled by functional multiparameter flow cytometry (MFC). Distinct regions from 16 pulmonary metastases (PMs) were microdissected, and RNA was extracted to perform comparative transcriptomic studies. Clinical follow-up (median 24 months) was available from resection.ResultsDigital image analysis of immunohistochemistry demonstrated significantly higher infiltrating immune cells in the PMs compared to primary bone tumors, concentrated at the tumor-normal lung ‘PM interface’ region, and elevated expression of multiple immune checkpoint molecules at the PM interface (figure 1). MFC confirmed the increased expression of the immune checkpoint molecules programmed cell death 1 (PD-1, p<0.01) and lymphocyte activation gene 3 (LAG-3, p<0.01), as well as the activation marker IFN-γ (p<0.05) in CD8+ TILs. Gene expression profiling provided further evidence for the presence of TILs with expression of activation markers and inhibitory immune checkpoint molecules at the PM interface compared to the PM interior (figure 2). A strong M2 macrophage signature was present in both regions. Further analysis revealed that genes related to neutrophil and myeloid cell chemotaxis and known to be associated with polymorphonuclear myeloid-derived suppressor cells were highly expressed at the PM interface, along with genes for multiple subsets of dendritic cells (figure 3). Expression of PD-L1, LAG-3, and CSF1R at the PM interface were associated with worse progression-free survival (PFS), while gene sets associated with productive T cell immune response were associated with improved PFS (figure 4).Abstract 506 Figure 1Immunohistochemistry of osteosarcoma pulmonary metastasesA. H&E with demarcation of tumor-normal lung interface (center green line) and area quantified as the ‘PM interface’ (outer green lines). Pulmonary metastases demonstrate a higher concentration of immune cells (CD3 p<0.001, CD8 p<0.001, CD163 p<0.01) and PD-1 (p<0.001)/PD-L1 (p<0.05) at the PM interface.B. H&E with demarcation of PM interface as above. Pulmonary metastases demonstrating increased staining of TIM-3 (p<0.01), LAG-3 (p<0.01) and IDO1 (p<0.0001) at the PM interface (no significant concentration of CSF1R at PM interface).Abstract 506 Figure 2Activated/exhausted lymphocyte signatures at PM interfaceA. Heatmap displaying significant genes that contribute to leading-edge of core enrichment subset via Gene Set Enrichment Analysis (GSEA) demonstrating higher expression of immune regulatory molecules at the PM interface compared to the PM interior. Expression levels were converted into heatmaps and colors quantitatively correspond to fold changes. FDR=GSEA false-discovery rate q-value.B. Heatmap illustrating coefficients of xCell analysis shows higher expression of markers of cytotoxicity and activation, as well as multiple checkpoint molecules, at the PM interface, with evidence that they are being contributed chiefly by T cells. Intensity represents xCell coefficient, which corresponds to the amount that a particular region (PM interior or PM interface) or cell population (T cells, B cells, or myeloid cells) contributes to the expression of a specific gene.Abstract 506 Figure 3Genes related to dendritic cells and MDSCs at PM interfaceA. By GSEA, genes associated with multiple subclasses of antigen-presenting dendritic cells are significantly upregulated at the PM interface (cDC1=conventional type 1 dendritic cell; cDC2=conventional type 2 dendritic cell; pDC=plasmacytoid dendritic cell; moDC=monocyte-derived dendritic cell). FDR=GSEA false-discovery rate q-value.B. Heatmap shows heightened expression of cytokines, chemokines and endothelin transcripts associated with development, recruitment and maintenance of PMNs and granulocytic MDSCs at the PM interface compared to the PM interior.Abstract 506 Figure 4Markers of immune TME at PM interface correlate with PFSA. Hazard ratios for immunohistochemistry markers at the PM interface as they relate to PFS. For absolute count biomarkers (CD3, CD8, Foxp3, PD-1, CD163, and LAG-3) the unit is per 100 cells, and for percentage biomarkers (PD-L1, CSF1R, TIM-3, and IDO1) the unit is per 1%.B. Hazard ratios for gene sets at the PM interface as they relate to PFS. NS=p>0.05, *p<0.05, **p<0.01, ***p<0.001, ****p<0.0001ConclusionsIn contrast to primary bone osteosarcoma ‘immune deserts,’ osteosarcoma PMs represent an ‘immune-excluded’ TME where immune cells are present but are halted at the PM interface. TILs can produce effector cytokines, suggesting their capability of activation and recognition of tumor antigens. Our findings suggest cooperative immunosuppressive mechanisms in osteosarcoma PMs that prevent TILs from penetrating into the PM interior, including immune checkpoint molecule expression and the presence of immunosuppressive myeloid cells. We identify cellular and molecular signatures that are associated with PFS of patients, which could be potentially manipulated for successful immunotherapy.Ethics ApprovalThis study was approved by Johns Hopkins University’s Ethics Board, approval number FWA00005752.ReferencesMirabello L, Troisi RJ, Savage SA. Osteosarcoma incidence and survival rates from 1973 to 2004: Data from the surveillance, epidemiology, and end results program. Cancer 2009;115(7):1531–43.Tawbi HA, Burgess M, Bolejack V, Van Tine BA, Schuetze SM, Hu J, et al. Pembrolizumab in advanced soft-tissue sarcoma and bone sarcoma (SARC028): A multicentre, two-cohort, single-arm, open-label, phase 2 trial. Lancet Oncol 2017;18(11):1493–501.Davis KL, Fox E, Merchant MS, Reid JM, Kudgus RA, Liu X, et al. Nivolumab in children and young adults with relapsed or refractory solid tumours or lymphoma (ADVL1412): A multicentre, open-label, single-arm, phase 1–2 trial. Lancet Oncol 2020;21(4):541–50.D’Angelo SP, Mahoney MR, Van Tine BA, Atkins J, Milhem MM, Jahagirdar BN, et al. Nivolumab with or without ipilimumab treatment for metastatic sarcoma (alliance A091401): Two open-label, non-comparative, randomised, phase 2 trials. Lancet Oncol 2018;19(3):416–26.Paoluzzi L, Cacavio A, Ghesani M, Karambelkar A, Rapkiewicz A, Weber J, et al. Response to anti-PD1 therapy with nivolumab in metastatic sarcomas. Clin Sarcoma Res 2016;6:24.
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Smith, Nancy J., Sara Y. Markowitz, Ann N. Hoffman e Michael S. Fanselow. "Adaptation of Threat Responses Within the Negative Valence Framework". Frontiers in Systems Neuroscience 16 (26 maggio 2022). http://dx.doi.org/10.3389/fnsys.2022.886771.
Abstract (sommario):
External threats are a major source of our experience of negatively valanced emotion. As a threat becomes closer and more real, our specific behavior patterns and our experiences of negative affect change in response to the perceived imminence of threat. Recognizing this, the National Institute of Mental Health’s Research Domain Criteria (RDoC) Negative Valence system is largely based around different levels of threat imminence. This perspective describes the correspondence between the RDoC Negative Valence System and a particular neurobiological/neuroecological model of reactions to threat, the Predatory Imminence Continuum (PIC) Theory. Using the COVID-19 pandemic as an illustration, we describe both adaptive and maladaptive behavior patterns from this perspective to illustrate how behavior in response to a crisis may get shaped. We end with suggestions on how further consideration of the PIC suggests potential modifications of the negative valence systems RDoC.
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Oh, Jooseong, Sung-Gwon Lee e Chungoo Park. "PIC-Me: paralogs and isoforms classifier based on machine-learning approaches". BMC Bioinformatics 22, S11 (ottobre 2021). http://dx.doi.org/10.1186/s12859-021-04229-x.
Abstract (sommario):
Abstract Background Paralogs formed through gene duplication and isoforms formed through alternative splicing have been important processes for increasing protein diversity and maintaining cellular homeostasis. Despite their recognized importance and the advent of large-scale genomic and transcriptomic analyses, paradoxically, accurate annotations of all gene loci to allow the identification of paralogs and isoforms remain surprisingly incomplete. In particular, the global analysis of the transcriptome of a non-model organism for which there is no reference genome is especially challenging. Results To reliably discriminate between the paralogs and isoforms in RNA-seq data, we redefined the pre-existing sequence features (sequence similarity, inverse count of consecutive identical or non-identical blocks, and match-mismatch fraction) previously derived from full-length cDNAs and EST sequences and described newly discovered genomic and transcriptomic features (twilight zone of protein sequence alignment and expression level difference). In addition, the effectiveness and relevance of the proposed features were verified with two widely used support vector machine (SVM) and random forest (RF) models. From nine RNA-seq datasets, all AUC (area under the curve) scores of ROC (receiver operating characteristic) curves were over 0.9 in the RF model and significantly higher than those in the SVM model. Conclusions In this study, using an RF model with five proposed RNA-seq features, we implemented our method called Paralogs and Isoforms Classifier based on Machine-learning approaches (PIC-Me) and showed that it outperformed an existing method. Finally, we envision that our tool will be a valuable computational resource for the genomics community to help with gene annotation and will aid in comparative transcriptomics and evolutionary genomics studies, especially those on non-model organisms.
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Poleksic, Joko, Milan Aksic, Slobodan Kapor, Dubravka Aleksic, Tihomir Stojkovic, Marina Radovic, Vuk Djulejic, Branka Markovic e Antonios Stamatakis. "Effects of Maternal Deprivation on the Prefrontal Cortex of Male Rats: Cellular, Neurochemical, and Behavioral Outcomes". Frontiers in Behavioral Neuroscience 15 (8 novembre 2021). http://dx.doi.org/10.3389/fnbeh.2021.666547.
Abstract (sommario):
Stressful events experienced during early life are associated with increased vulnerability of developing psychopathology in adulthood. In the present study, we exposed 9-day-old Wistar rats to 24 h maternal deprivation (MD) with the aim to investigate the impact of early life stress (ELS) on morphological, biochemical, and functional aspects of the prefrontal cortex (PFC), a brain region particularly sensitive to stress. We found that in the superficial medial orbital cortex (MO), young adult male rats had reduced density of GAD67 and CCK immunopositive cells, while the rostral part of the ventral lateral orbital cortex (roVLO) showed a decrease in the density of GAD67 immunopositive cells in both superficial and deep layers. In addition, the superficial rostral part of area 1 of the cingulate cortex (roCg1) and deep prelimbic cortex (PrL) was also affected by MD indicated by the reduction in PV immunopositive cellular density. Furthermore, MD induced upregulation of brain-derived neurotrophic factor (BDNF), while it did not affect the overall expression of Iba1 in neonatal or young adult PFC as measured by Western blot, however, microglial activation in young adult MD rats was detected immunohistochemically in deep layers of MO and infralimbic cortex (IL). Interestingly, when young adult male rats were subjected to a behavioral flexibility test in a T-maze, MD rats showed a subtle impairment in T-maze reversal learning indicating a mildly affected PFC function. Taken together, our findings demonstrated that MD reduced the density of interneurons and induced microglial activation, in particular, PFC areas at young adulthood, and could alter synaptic plasticity accompanied by PFC dysfunction.
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Cheng, Yi, Nan Song, Renkai Ge e Yue Dai. "Serotonergic Modulation of Persistent Inward Currents in Serotonergic Neurons of Medulla in ePet-EYFP Mice". Frontiers in Neural Circuits 15 (6 aprile 2021). http://dx.doi.org/10.3389/fncir.2021.657445.
Abstract (sommario):
Serotonergic (5-HT) neurons in the medulla play multiple functional roles associated with many symptoms and motor activities. The descending serotonergic pathway from medulla is essential for initiating locomotion. However, the ionic properties of 5-HT neurons in the medulla remain unclear. Using whole-cell patch-clamp technique, we studied the biophysical and modulatory properties of persistent inward currents (PICs) in 5-HT neurons of medulla in ePet-EYFP transgenic mice (P3–P6). PICs were recorded by a family of voltage bi-ramps (10-s duration, 40-mV peak step), and the ascending and descending PICs were mirrored to analyze the PIC hysteresis. PICs were found in 77% of 5-HT neurons (198/258) with no significant difference between parapyramidal region (n = 107) and midline raphe nuclei (MRN) (n = 91) in either PIC onset (−47.4 ± 10 mV and −48.7 ± 7 mV; P = 0.44) or PIC amplitude (226.9 ± 138 pA and 259.2 ± 141 pA; P = 0.29). Ninety-six percentage (191/198) of the 5-HT neurons displayed counterclockwise hysteresis and four percentage (7/198) exhibited the clockwise hysteresis. The composite PICs could be differentiated as calcium component (Ca_PIC) by bath application of nimodipine (25 μM), sodium component (Na_PIC) by tetrodotoxin (TTX, 2 μM), and TTX- and dihydropyridine-resistance component (TDR_PIC) by TTX and nimodipine. Ca_PIC, Na_PIC and TDR_PIC all contributed to upregulation of excitability of 5-HT neurons. 5-HT (15 μM) enhanced the PICs, including a 26% increase in amplitude of the compound currents of Ca_PIC and TDR_PIC (P < 0.001, n = 9), 3.6 ± 5 mV hyperpolarization of Na_PIC and TDR_PIC onset (P < 0.05, n = 12), 30% increase in amplitude of TDR_PIC (P < 0.01), and 2.0 ± 3 mV hyperpolarization of TDR_PIC onset (P < 0.05, n = 18). 5-HT also facilitated repetitive firing of 5-HT neurons through modulation of composite PIC, Na_PIC and TDR_PIC, and Ca_PIC and TDR_PIC, respectively. In particular, the high voltage-activated TDR_PIC facilitated the repetitive firing in higher membrane potential, and this facilitation could be amplified by 5-HT. Morphological data analysis indicated that the dendrites of 5-HT neurons possessed dense spherical varicosities intensively crossing 5-HT neurons in medulla. We characterized the PICs in 5-HT neurons and unveiled the mechanism underlying upregulation of excitability of 5-HT neurons through serotonergic modulation of PICs. This study provided insight into channel mechanisms responsible for the serotonergic modulation of serotonergic neurons in brainstem.
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Saha, Rajib, Deng Liu, Allison Hoynes-O’Connor, Michelle Liberton, Jingjie Yu, Maitrayee Bhattacharyya-Pakrasi, Andrea Balassy et al. "Diurnal Regulation of Cellular Processes in the Cyanobacterium Synechocystis sp. Strain PCC 6803: Insights from Transcriptomic, Fluxomic, and Physiological Analyses". mBio 7, n. 3 (3 maggio 2016). http://dx.doi.org/10.1128/mbio.00464-16.
Abstract (sommario):
ABSTRACT Synechocystis sp. strain PCC 6803 is the most widely studied model cyanobacterium, with a well-developed omics level knowledgebase. Like the lifestyles of other cyanobacteria, that of Synechocystis PCC 6803 is tuned to diurnal changes in light intensity. In this study, we analyzed the expression patterns of all of the genes of this cyanobacterium over two consecutive diurnal periods. Using stringent criteria, we determined that the transcript levels of nearly 40% of the genes in Synechocystis PCC 6803 show robust diurnal oscillating behavior, with a majority of the transcripts being upregulated during the early light period. Such transcripts corresponded to a wide array of cellular processes, such as light harvesting, photosynthetic light and dark reactions, and central carbon metabolism. In contrast, transcripts of membrane transporters for transition metals involved in the photosynthetic electron transport chain (e.g., iron, manganese, and copper) were significantly upregulated during the late dark period. Thus, the pattern of global gene expression led to the development of two distinct transcriptional networks of coregulated oscillatory genes. These networks help describe how Synechocystis PCC 6803 regulates its metabolism toward the end of the dark period in anticipation of efficient photosynthesis during the early light period. Furthermore, in silico flux prediction of important cellular processes and experimental measurements of cellular ATP, NADP(H), and glycogen levels showed how this diurnal behavior influences its metabolic characteristics. In particular, NADPH/NADP + showed a strong correlation with the majority of the genes whose expression peaks in the light. We conclude that this ratio is a key endogenous determinant of the diurnal behavior of this cyanobacterium. IMPORTANCE Cyanobacteria are photosynthetic microbes that use energy from sunlight and CO 2 as feedstock. Certain cyanobacterial strains are amenable to facile genetic manipulation, thus enabling synthetic biology and metabolic engineering applications. Such strains are being developed as a chassis for the sustainable production of food, feed, and fuel. To this end, a holistic knowledge of cyanobacterial physiology and its correlation with gene expression patterns under the diurnal cycle is warranted. In this report, a genomewide transcriptional analysis of Synechocystis PCC 6803, the most widely studied model cyanobacterium, sheds light on the global coordination of cellular processes during diurnal periods. Furthermore, we found that, in addition to light, the redox level of NADP(H) is an important endogenous regulator of diurnal entrainment of Synechocystis PCC 6803.
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Ngolsou, Françis, Eya’ane Meva François, Mésodé Nnangé Akweh, Patrick Hervé Bétoté Diboué, Nko’o Julien Moise Henri, Fifen Rodrigue, Tchangou Njiemou Armel Florian et al. "Évaluation in vivo de l’effet anti-inflammatoire des nanoparticules d'argent obtenues par biosynthèse in situ à partir des feuilles de Psychotria calceata". Journal Africain de Technologie Pharmaceutique et Biopharmacie (JATPB) 2, n. 3 (20 dicembre 2023). http://dx.doi.org/10.57220/jatpb.v2i3.119.
Abstract (sommario):
Introduction : Les nanotechnologies sont de nos jours une science qui prend une grande importance en raison de leur simplicité, de leur nature écologique et économique. L’objectif de ce travail consistait à évaluer l’effet anti-inflammatoire des nanoparticules obtenues par biosynthèse in situ à partir de la poudre des feuilles de Psychotria calceata.
Matériel et méthodes : La synthèse des nanomatériaux s’est faite à partir d’un infusé de la poudre des feuilles de Psychotria calceata auquel a été ajouté une solution de nitrate d’argent. Les nanoparticules obtenues ont été caractérisées après changement de coloration visuel, au spectrophotomètre d’absorption UV-Vis entre 380 et 550nm. Cette caractérisation consistait à observer la formation des nanoparticules à partir de l'apparition de la résonance plasmonique de surface et d’apprécier leur stabilité. La toxicité orale aiguë des nanoparticules a été réalisée sur des rats Wistar selon le protocole décrit par la ligne directrice 423 (2001) de l'Organisation de Coopération et de Développement économique (OCDE). Un modèle d'œdème plantaire de la patte de rat induit par la carraghénine a été utilisé pour évaluer l’activité anti-inflammatoire de ces nanoparticules et des coupes histologiques ont été réalisées sur le foie, la rate, le cœur et les reins.
Résultats et Discussion : Le criblage phytochimique de l'extrait aqueux de Psychotria calceata a révélé la présence d'alcaloïdes, phénols, polyphénols, tanins, saponines, flavonoïdes, triterpènes et stéroïdes. Le pic de résonance plasmonique de surface dans le spectre UV-Vis montre des spectres d'absorption compris entre 380 et 500 nm caractéristique de la présence des particules de taille nanométrique. Leur profil toxicologique a montré une DL50 > 2000mg/kg. A la dose de 400µg, les nanoparticules ont montré une diminution significative à p<0,01, trois heures après l'administration des nanoparticules. Conclusion : Les nanoparticules d'argent peuvent agir comme agents réducteurs/inhibiteurs de la libération des médiateurs inflammatoires aigus. Par conséquent, ce travail a clairement démontré que les nanoparticules d'argent de Psychotria calceata pourraient être considérées comme une source potentielle de médicaments anti-inflammatoires.
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Hauer, Brandon E., Silvia Pagliardini e Clayton T. Dickson. "Prefrontal-Hippocampal Pathways Through the Nucleus Reuniens Are Functionally Biased by Brain State". Frontiers in Neuroanatomy 15 (31 gennaio 2022). http://dx.doi.org/10.3389/fnana.2021.804872.
Abstract (sommario):
Circuit-level communication between disparate brain regions is fundamental for the complexities of the central nervous system operation. Co-ordinated bouts of rhythmic activity between the prefrontal cortex (PFC) and hippocampus (HPC), in particular, are important for mnemonic processes. This is true during awake behavior, as well as during offline states like sleep. We have recently shown that the anatomically interposed thalamic nucleus reuniens (RE) has a role in coordinating slow-wave activity between the PFC and HPC. Here, we took advantage of spontaneous brain state changes occurring during urethane anesthesia in order to assess if PFC-HPC communication was modified during activated (theta) vs. deactivated (slow oscillation: SO) states. These forebrain states are highly similar to those expressed during rapid eye movement (REM) and non-REM stages of natural sleep, respectively. Evoked potentials and excitatory current sinks in the HPC were consistently larger during SO states, regardless of whether PFC or RE afferents were stimulated. Interestingly, PFC stimulation during theta appeared to preferentially use a cortico-cortical pathway, presumably involving the entorhinal cortex as opposed to the more direct RE to HPC conduit. Optogenetic and chemogenetic manipulations of the RE suggested that this state-dependent biasing was mediated by responding in the RE itself. Finally, the phase of both ongoing rhythms also appeared to be an important factor in modulating HPC responses, with maximal field excitatory postsynaptic potentials (EPSPs) occurring during the negative-going phase of both rhythms. Thus, forebrain state plays an important role in how communication takes place across the PFC and HPC, with the RE as a determining factor in how this is shaped. Furthermore, ongoing sleep-like rhythms influence the coordination and perhaps potentiate excitatory processing in this extended episodic memory circuit. Our results have direct implications for activity-dependent processes relevant to sleep-dependent memory consolidation.
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Wang, Yifan, Ruiyan Liu, Hong Liu, Xihai Li, Linjing Shen, Weican Zhang, Xin Song, Weifeng Liu, Xiangmei Liu e Yaohua Zhong. "Development of a powerful synthetic hybrid promoter to improve the cellulase system of Trichoderma reesei for efficient saccharification of corncob residues". Microbial Cell Factories 21, n. 1 (4 gennaio 2022). http://dx.doi.org/10.1186/s12934-021-01727-8.
Abstract (sommario):
Abstract Background The filamentous fungus Trichoderma reesei is a widely used workhorse for cellulase production in industry due to its prominent secretion capacity of extracellular cellulolytic enzymes. However, some key components are not always sufficient in this cellulase cocktail, making the conversion of cellulose-based biomass costly on the industrial scale. Development of strong and efficient promoters would enable cellulase cocktail to be optimized for bioconversion of biomass. Results In this study, a synthetic hybrid promoter was constructed and applied to optimize the cellulolytic system of T. reesei for efficient saccharification towards corncob residues. Firstly, a series of 5’ truncated promoters in different lengths were established based on the strong constitutive promoter Pcdna1. The strongest promoter amongst them was Pcdna1-3 (− 640 to − 1 bp upstream of the translation initiation codon ATG), exhibiting a 1.4-fold higher activity than that of the native cdna1 promoter. Meanwhile, the activation region (− 821 to − 622 bp upstream of the translation initiation codon ATG and devoid of the Cre1-binding sites) of the strong inducible promoter Pcbh1 was cloned and identified to be an amplifier in initiating gene expression. Finally, this activation region was fused to the strongest promoter Pcdna1-3, generating the novel synthetic hybrid promoter Pcc. This engineered promoter Pcc drove strong gene expression by displaying 1.6- and 1.8-fold stronger fluorescence intensity than Pcbh1 and Pcdna1 under the inducible condition using egfp as the reporter gene, respectively. Furthermore, Pcc was applied to overexpress the Aspergillus niger β-glucosidase BGLA coding gene bglA and the native endoglucanase EG2 coding gene eg2, achieving 43.5-fold BGL activity and 1.2-fold EG activity increase, respectively. Ultimately, to overcome the defects of the native cellulase system in T. reesei, the bglA and eg2 were co-overexpressed under the control of Pcc promoter. The bglA-eg2 double expression strain QPEB70 exhibited a 178% increase in total cellulase activity, whose cellulase system displayed 2.3- and 2.4-fold higher saccharification efficiency towards acid-pretreated and delignified corncob residues than the parental strain, respectively. Conclusions The synthetic hybrid promoter Pcc was generated and employed to improve the cellulase system of T. reesei by expressing specific components. Therefore, construction of synthetic hybrid promoters would allow particular cellulase genes to be expressed at desired levels, which is a viable strategy to optimize the cellulolytic enzyme system for efficient biomass bioconversion.