Academic literature on the topic 'Receptor depletion'
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Journal articles on the topic "Receptor depletion"
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Frey, A. B. "Role of host antigen receptor-bearing and antigen receptor-negative cells in immune response to rat adenocarcinoma 13762." Journal of Immunology 156, no. 10 (May 15, 1996): 3841–49. http://dx.doi.org/10.4049/jimmunol.156.10.3841.
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Abstract Involvement of individual immune cell populations in the immune response to rat breast adenocarcinoma 13762 was studied by selective depletion treatments in vivo. Depletion of Ag nonspecific host defense cells from naive animals before tumor challenge resulted in statistically significant acceleration of tumor growth (p less than 0.01 or less), whereas depletion of either CD4+ T cells or CD8+ T cells had no effect on the incidence or kinetics of tumor development. In contrast to naive animals treated before tumor challenge, animals actively immunized by injection of irradiated tumor before depleting treatments were shown to require CD4+ T cells to reject tumorigenic challenge. Depletion of either macrophages or neutrophils from immune animals also increased tumor development, whereas NK cells were not involved. Depletion of CD8+ T cells from immune animals permitted transient growth of tumors that were subsequently rejected, implying a role in tumor rejection. Transfer of immune antiserum to naive animals at the time of tumor challenge was without effect on tumor development. Depletion of CD4+ T cells, neutrophils, or macrophages in the priming phase of antitumor immune response abrogated tumor immunity, but depletion of CD8+ T cells or NK cells was without effect on the ability to prime animals by immunization with irradiated cells. Collectively, these data suggest that host natural defense cells that do not express Ag receptor are primarily responsible for resistance of adenocarcinoma 13762 growth in naive animals. In contrast, tumor immunity induced by active immunization requires Ag receptor-bearing CD4+ T cells and involves participation of CD8+ T cells, neutrophils, or macrophages in elimination of tumor.
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Ray, P. E., E. Castren, E. J. Ruley, and J. M. Saavedra. "Different effects of sodium or chloride depletion on angiotensin II receptors in rats." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 258, no. 4 (April 1, 1990): R1008—R1015. http://dx.doi.org/10.1152/ajpregu.1990.258.4.r1008.
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We studied the effects of selective chronic sodium or chloride depletion (0.005% in diet) on central and peripheral angiotensin II receptors in young rats. Chloride depletion produced the most significant increase in plasma renin activity and extracellular fluid volume contraction. In the brain, subfornical organ angiotensin II receptor concentration was decreased by sodium depletion and increased by chloride depletion. There were no significant changes in angiotensin II binding in the paraventricular nucleus. When sodium-depleted rats were water deprived for 3 days, subfornical organ angiotensin II receptor concentration increased, showing that normal sodium intake was not essential for increased numbers of angiotensin II receptors during dehydration. In the adrenal gland, chloride depletion decreased angiotensin II receptors in the medulla and zona glomerulosa. Conversely, sodium depletion increased angiotensin II receptors in the zona glomerulosa. In the kidney glomeruli and medulla, angiotensin II receptors were decreased by either sodium or chloride depletion. These results suggest different roles for sodium and chloride in the regulation of the peripheral and central renin-angiotensin system in young rats.
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Aoh, Quyen L., Anna M. Castle, Charles H. Hubbard, Osamu Katsumata, and J. David Castle. "SCAMP3 Negatively Regulates Epidermal Growth Factor Receptor Degradation and Promotes Receptor Recycling." Molecular Biology of the Cell 20, no. 6 (March 15, 2009): 1816–32. http://dx.doi.org/10.1091/mbc.e08-09-0894.
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The epidermal growth factor receptor (EGFR) is targeted for lysosomal degradation by ubiquitin-mediated interactions with the ESCRTs (endosomal-sorting complexes required for transport) in multivesicular bodies (MVBs). We show that secretory carrier membrane protein, SCAMP3, localizes in part to early endosomes and negatively regulates EGFR degradation through processes that involve its ubiquitylation and interactions with ESCRTs. SCAMP3 is multimonoubiquitylated and is able to associate with Nedd4 HECT ubiquitin ligases and the ESCRT-I subunit Tsg101 via its PY and PSAP motifs, respectively. SCAMP3 also associates with the ESCRT-0 subunit Hrs. Depletion of SCAMP3 in HeLa cells by inhibitory RNA accelerated degradation of EGFR and EGF while inhibiting recycling. Conversely, overexpression enhanced EGFR recycling unless ubiquitylatable lysines, PY or PSAP motifs in SCAMP3 were mutated. Notably, dual depletions of SCAMP3 and ESCRT subunits suggest that SCAMP3 has a distinct function in parallel with the ESCRTs that regulates receptor degradation. This function may affect trafficking of receptors from prelysosomal compartments as SCAMP3 depletion appeared to sustain the incidence of EGFR-containing MVBs detected by immunoelectron microscopy. Together, our results suggest that SCAMP3, its modification with ubiquitin, and its interactions with ESCRTs coordinately regulate endosomal pathways and affect the efficiency of receptor down-regulation.
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Lu, Justine P., Yuan Wang, Danielle A. Sliter, Margaret M. P. Pearce, and Richard J. H. Wojcikiewicz. "RNF170 Protein, an Endoplasmic Reticulum Membrane Ubiquitin Ligase, Mediates Inositol 1,4,5-Trisphosphate Receptor Ubiquitination and Degradation." Journal of Biological Chemistry 286, no. 27 (May 24, 2011): 24426–33. http://dx.doi.org/10.1074/jbc.m111.251983.
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Inositol 1,4,5-trisphosphate (IP3) receptors are endoplasmic reticulum membrane calcium channels that, upon activation, are degraded via the ubiquitin-proteasome pathway. While searching for novel mediators of IP3 receptor processing, we discovered that RNF170, an uncharacterized RING domain-containing protein, associates rapidly with activated IP3 receptors. RNF170 is predicted to have three membrane-spanning helices, is localized to the ER membrane, and possesses ubiquitin ligase activity. Depletion of endogenous RNF170 by RNA interference inhibited stimulus-induced IP3 receptor ubiquitination, and degradation and overexpression of a catalytically inactive RNF170 mutant suppressed stimulus-induced IP3 receptor processing. A substantial proportion of RNF170 is constitutively associated with the erlin1/2 (SPFH1/2) complex, which has been shown previously to bind to IP3 receptors immediately after their activation. Depletion of RNF170 did not affect the binding of the erlin1/2 complex to stimulated IP3 receptors, whereas erlin1/2 complex depletion inhibited RNF170 binding. These results suggest a model in which the erlin1/2 complex recruits RNF170 to activated IP3 receptors where it mediates IP3 receptor ubiquitination. Thus, RNF170 plays an essential role in IP3 receptor processing via the ubiquitin-proteasome pathway.
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Lièvremont, Jean-Philippe, Gary St J. Bird, and James W. Putney. "Canonical transient receptor potential TRPC7 can function as both a receptor- and store-operated channel in HEK-293 cells." American Journal of Physiology-Cell Physiology 287, no. 6 (December 2004): C1709—C1716. http://dx.doi.org/10.1152/ajpcell.00350.2004.
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Previous studies on the activation mechanism of canonical transient receptor potential (TRPC) channels have often produced conflicting conclusions. All seven have been shown to be activated by phospholipase C (PLC)-coupled receptors, but TRPC1, TRPC2, TRPC3, TRPC4, TRPC5, and TRPC7 have also been proposed to function as store-operated channels. 1 1 Although PLC activation inevitably leads to activation of store-operated channels, in this report when we refer to PLC-activated channels, we mean those channels that are specifically activated by PLC independently of store depletion. In the case of TRPC3, the expression environment and the expression level appear to determine the mode of regulation. Evidence of a close structural relative of TRPC3, TRPC7, has been presented that this channel is activated by receptor activation or by store depletion. On the basis of previous findings for TRPC3, we reasoned that subtle differences in structure or expression conditions might account for the apparent distinct gating mechanisms of TRPC7. To reexamine the mode of activation of TRPC7, we stably and transiently transfected human embryonic kidney (HEK)-293 cells with cDNA encoding for human TRPC7. We examined the ability of a PLC-activating agonist and an intracellular Ca2+ store-depleting agent to activate these channels. Our findings demonstrate that when transiently expressed in HEK-293 cells, TRPC7 forms channels that are activated by PLC-stimulating agonists, but not by Ca2+ store depletion. However, when stably expressed in HEK-293 cells, TRPC7 can be activated by either Ca2+ store depletion or PLC activation. To our knowledge, this is the first demonstration of a channel protein that can be activated by both receptor- and store-operated modes in the same cell. In addition, the results reconcile the apparently conflicting findings of other laboratories regarding TRPC7 regulation.
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Kyakumoto, S., R. Kurokawa, and M. Ota. "Mechanism of replenishment of androgen receptors in cytosol of mouse submandibular gland." Journal of Endocrinology 115, no. 3 (December 1987): 411–18. http://dx.doi.org/10.1677/joe.0.1150411.
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ABSTRACT Female mice were used to examine the process of depletion and replenishment of cytosolic androgen receptors in submandibular glands, and to investigate the effects of cycloheximide and actinomycin D on these processes. The dose-dependence of receptor depletion and replenishment in the cytosolic fraction, and that of receptor accumulation in the nuclear fraction were investigated. Almost 100% depletion was revealed 1 h after the injection of testosterone propionate at a dose of 500 or 50 μg testosterone/100 g body weight. With a 5 μg dose, depletion of cytosolic receptors was not complete and replenishment proceeded rapidly compared with that which occurred with the 50 or 500 μg dose. The nuclear receptor level increased 1 h after injection of testosterone, and the raised level was gradually reduced to the pretreatment level with all doses. However, the time required for this return to pretreatment level was dependent on the dose of testosterone. The change in the levels of cytosolic and nuclear androgen receptors following injection of testosterone was parallel to the level of circulating androgen. To determine the requirements for transcriptional and translational events in the replenishment process, cycloheximide and actinomycin D were given in vivo. The process of replenishment of cytosolic receptors was inhibited by the injection of cycloheximide. However, actinomycin D exerted no inhibitory effect on receptor replenishment. Neither cycloheximide nor actinomycin D had any effect on the nuclear receptor level until 6 h after the injection of testosterone. Cycloheximide or actinomycin D alone had no effect on the cytosolic or nuclear receptor level. These results suggest that receptor replenishment involves protein synthesis. J. Endocr. (1987) 115, 411–418
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Peterson, Theresa J., Sudipan Karmakar, Margaret C. Pace, Tong Gao, and Carolyn L. Smith. "The Silencing Mediator of Retinoic Acid and Thyroid Hormone Receptor (SMRT) Corepressor Is Required for Full Estrogen Receptor α Transcriptional Activity." Molecular and Cellular Biology 27, no. 17 (June 25, 2007): 5933–48. http://dx.doi.org/10.1128/mcb.00237-07.
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ABSTRACT Multiple factors influence estrogen receptor α (ERα) transcriptional activity. Current models suggest that the silencing mediator of retinoic acid and thyroid hormone receptor (SMRT) corepressor functions within a histone deactylase-containing protein complex that binds to antiestrogen-bound ERα and contributes to negative regulation of gene expression. In this report, we demonstrate that SMRT is required for full agonist-dependent ERα activation. Chromatin immunoprecipitation assays demonstrate that SMRT, like ERα and the SRC-3 coactivator, is recruited to an estrogen-responsive promoter in estrogen-treated MCF-7 cells. Depletion of SMRT, but not histone deacetylases 1 or 3, negatively impacts estradiol-stimulated ERα transcriptional activity, while exogenous expression of SMRT's receptor interaction domains blocks ERα activity, indicating a functional interaction between this corepressor and agonist-bound ERα. Stimulation of estradiol-induced ERα activity by SMRT overexpression occurred in HeLa and MCF-7 cells, but not HepG2 cells, indicating that these positive effects are cell type specific. Similarly, the ability of SMRT depletion to promote the agonist activity of tamoxifen was observed for HeLa but not MCF-7 cells. Furthermore, impairment of agonist-stimulated activity by SMRT depletion is specific to ERα and not observed for receptors for vitamin D, androgen, or thyroid hormone. Nuclear receptor corepressor (N-CoR) depletion increased the transcriptional activity of all four tested receptors. SMRT is required for full expression of the ERα target genes cyclin D1, BCL-2, and progesterone receptor but not pS2, and its depletion significantly attenuated estrogen-dependent proliferation of MCF-7 cells. Taken together, these data indicate that SMRT, in conjunction with gene-specific and cell-dependent factors, is required for positively regulating agonist-dependent ERα transcriptional activity.
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Linas, S. L., R. Marzec-Calvert, and M. E. Ullian. "K depletion alters angiotensin II receptor expression in vascular smooth muscle cells." American Journal of Physiology-Cell Physiology 258, no. 5 (May 1, 1990): C849—C854. http://dx.doi.org/10.1152/ajpcell.1990.258.5.c849.
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Dietary K depletion (KD) results in increases in the number of angiotensin II (ANG II) receptors and prevents ANG II-induced downregulation of ANG II receptors in membrane preparations of vessels from KD animals. Because dietary KD results in changes in factors other than K, we K depleted vascular smooth muscle cells (VSMC) in culture to determine the specific effects of KD on ANG II receptor expression and processing. Scatchard analysis of ANG II uptake at 4 degrees C revealed that the number of surface receptors was increased by 37% in cells in which K had been reduced by 45%. This increase also occurred in the presence of cycloheximide. To determine the effect of KD on receptor processing, we measured the number of surface receptors after exposure to ANG II in concentrations sufficient to cause down-regulation. After 30-min exposure to ANG II, the number of surface receptors was reduced by 63% in control cells but only 33% in KD cells. Thirty minutes after withdrawing ANG II, surface binding returned to basal levels in control cells but was still reduced by 20% in KD cells. To determine the functional significance of impaired receptor processing, we measured ANG II uptake at 21 degrees C. Uptake at 21 degrees C depends on the functional number of receptors, i.e., the absolute number of surface receptors and the rate at which receptors are recycled to the surface after ANG II binding. ANG II uptake at 21 degrees C was reduced by 50% in KD cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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Morris, Gavin E., Carl P. Nelson, Paul J. Brighton, Nicholas B. Standen, R. A. John Challiss, and Jonathon M. Willets. "Arrestins 2 and 3 differentially regulate ETA and P2Y2 receptor-mediated cell signaling and migration in arterial smooth muscle." American Journal of Physiology-Cell Physiology 302, no. 5 (March 1, 2012): C723—C734. http://dx.doi.org/10.1152/ajpcell.00202.2011.
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Overstimulation of endothelin type A (ETA) and nucleotide (P2Y) Gαq-coupled receptors in vascular smooth muscle causes vasoconstriction, hypertension, and, eventually, hypertrophy and vascular occlusion. G protein-coupled receptor kinases (GRKs) and arrestin proteins are sequentially recruited by agonist-occupied Gαq-coupled receptors to terminate phospholipase C signaling, preventing prolonged/inappropriate contractile signaling. However, these proteins also play roles in the regulation of several mitogen-activated protein kinase (MAPK) signaling cascades known to be essential for vascular remodeling. Here we investigated whether different arrestin isoforms regulate endothelin and nucleotide receptor MAPK signaling in rat aortic smooth muscle cells (ASMCs). When intracellular Ca2+ levels were assessed in isolated ASMCs loaded with Ca2+-sensitive dyes, P2Y2 and ETA receptor desensitization was attenuated by selective small-interfering (si)RNA-mediated depletion of G protein-coupled receptor kinase 2 (GRK2). Using similar siRNA techniques, knockdown of arrestin2 prevented P2Y2 receptor desensitization and enhanced and prolonged p38 and ERK MAPK signals, while arrestin3 depletion was ineffective. Conversely, arrestin3 knockdown prevented ETA receptor desensitization and attenuated ET1-stimulated p38 and ERK signals, while arrestin2 depletion had no effect. Using Transwell assays to assess agonist-stimulated ASMC migration, we found that UTP-stimulated migration was markedly attenuated following arrestin2 depletion, while ET1-stimulated migration was attenuated following knockdown of either arrestin. These data highlight a differential arrestin-dependent regulation of ETA and P2Y2 receptor-stimulated MAPK signaling. GRK2 and arrestin expression are essential for agonist-stimulated ASMC migration, which, as a key process in vascular remodeling, highlights the potential roles of GRK2 and arrestin proteins in the progression of vascular disease.
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Clarke, David C., Meredith L. Brown, Richard A. Erickson, Yigong Shi, and Xuedong Liu. "Transforming Growth Factor β Depletion Is the Primary Determinant of Smad Signaling Kinetics." Molecular and Cellular Biology 29, no. 9 (February 17, 2009): 2443–55. http://dx.doi.org/10.1128/mcb.01443-08.
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ABSTRACT A cell's decision to growth arrest, apoptose, or differentiate in response to transforming growth factor β (TGF-β) superfamily ligands depends on the ligand concentration. How cells sense the concentration of extracellular bioavailable TGF-β remains poorly understood. We therefore undertook a systematic quantitative analysis of how TGF-β ligand concentration is transduced into downstream phospho-Smad2 kinetics, and we found that the rate of TGF-β ligand depletion is the principal determinant of Smad signal duration. TGF-β depletion is caused by two mechanisms: (i) cellular uptake of TGF-β by a TGF-β type II receptor-dependent mechanism and (ii) reversible binding of TGF-β to the cell surface. Our results indicate that cells sense TGF-β dose by depleting TGF-β via constitutive TGF-β type II receptor trafficking processes. Our results also have implications for the role of the TGF-β type II receptor in disease, as tumor cells harboring TGF-β type II receptor mutations exhibit impaired TGF-β depletion, which may contribute to the overproduction of TGF-β and a consequently poor prognosis in cancer.
Dissertations / Theses on the topic "Receptor depletion"
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Khoboko, Thabelo. "Effect of age and unilateral dopamine depletion on striatal NMDA receptor function." Master's thesis, University of Cape Town, 2005. http://hdl.handle.net/11427/3409.
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Casali, Brad Thomas. "Disease-Modifying Effects of Microglia Depletion and Nuclear Receptor Deletion inMyeloid Cells in Alzheimer's Disease." Case Western Reserve University School of Graduate Studies / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=case1599047858196611.
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Hughes, Simon Anthony. "Role of membrane PIP2 hydrolysis and depletion in receptor-induced inhibition of potassium M(Kv7)channels." Thesis, University College London (University of London), 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.506810.
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The M-current is a low-threshold and voltage gated potassium current with key roles in regulating neuronal excitability. M-channels have been found to be widely distributed throughout the central and peripheral nervous systems where channel abnormalities are known to contribute to several channelopathies. The channel can be regulated via Gq/11-coupled receptors such as the M1 muscarinic receptor which couples to phospholipase C (PLC) which acts to hydrolyze membrane phospholipid phosphatidylinositol 4,5-bisphosphate (PIP2). Efforts to elucidate the mechanisms surrounding the modulation of this channel have lead to a number of suggested signal transducers including membrane PIP2 and calcium. The first part of this study attempts to confirm and clarify the involvement of PIP2 in M-channel regulation by expressing the pleckstrin homology domain of phospholipase C tagged with green fluorescent protein (GFPPLCa- PH) in cells taken from rat superior cervical ganglia (SCG) in combination with voltage-clamp membrane current recording. Upon stimulation by the muscarinic agonist oxotremorine-M (oxo-M), the probe is seen to translocate from the membrane, bound primarily to PIP2, and bind the hydrolysis product cytosolic inositol 1.4,5- trisphosphate (IP3). Using novel techniques I was able to estimate resting membrane [PIP2] and predict changes in mechanism components during PIP2 hydrolysis. Fluorescence changes also showed a close temporal and concentration-dependent correlation with muscarinic M-current inhibition, consistent with the PIP2 gating hypothesis. Further clarification was then achieved by over-expressing phosphatidylinositol-4-phosphate-5-kinase (PI4(5)K), an enzyme involved in PIP2 synthesis. The activation of the B2-bradykinin receptor, another Gq/11-coupled receptor, has been suggested to act via IP3-induced Ca2+ release with concurrent up-regulation of PIP2 synthesis. In this situation calculations involving GFP-PLCa-PH break down due to the probes affinity for IP3. Hence the second part of this study involved using a probe which solely binds PIP2, the yellow fluorescence tagged C-terminus of the transcription factor tubby, mutated to reduce affinity for PIP2 and thus allow translocation (tubby-R332H-YFP). This probe, in conjunction with M-current measurements using further voltage clamp techniques, highlighted oxo-M as primarily acting via PIP2 depletion and bradykinin chiefly via IP3 and calcium, confirming my initial hypotheses.
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Thoma, Michelle C. "Regulating the regulators using CD25 depletion to enhance immune responses to a model plasmid-based vaccine /." Diss., Columbia, Mo. : University of Missouri-Columbia, 2008. http://hdl.handle.net/10355/5764.
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Thesis (M.S.)--University of Missouri-Columbia, 2008.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. "August 2008" Includes bibliographical references.
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Beiko, Jason. "The effect of nonspatial water maze pretraining in rats subjected to serotonin depletion and muscarinic receptor antagonism, a detailed behavioural assessment of spatial performance." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape16/PQDD_0008/MQ28540.pdf.
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Tirelle, Pauline. "Role du microbiote intestinal dans la régulation de l'axe intestin-cerveau au cours du modèle murin d'anorexie " activity-based anorexia Gut microbiota alteration in a mouse model of Anorexia Nervosa Comparison of different modes of antibiotic delivery on gut microbiota depletion efficiency and body composition in mouse Gut microbiota depletion affects nutritional and bahavioral responses to activity-based anorexia model in a sex-dependent manner Invalidation of Toll-like receptor 4 in intestinal epithelial cells modifies the response to activity base anorexia model in a sex-dependent manner." Thesis, Normandie, 2020. http://www.theses.fr/2020NORMR056.
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L’anorexie mentale (AN) est un trouble du comportement alimentaire (TCA) à prédominance féminine, principalement caractérisée par une diminution de l’apport alimentaire entrainant une forte perte de poids. Par ailleurs, de nombreuses comorbidités sont retrouvées à l’image de la dépression et de l’anxiété. Ces dernières années, l’étude du rôle de l’axe microbiote-intestin-cerveau dans les TCA ainsi que l’anxiété a gagné en intérêt. Ainsi, des études ont rapporté une dysbiose du microbiote intestinal chez les patients anorexiques. Cependant la physiopathologie de l’AN demeure à l’heure actuelle encore mal comprise. Le but des travaux menés au cours de cette thèse, a été d’étudier le rôle du microbiote dans l’axe intestin-cerveau, au cours du modèle murin d’anorexie, activity-based anorexia (ABA) combinant activité physique spontanée et diminution progressive du temps d’accès à l’alimentation. La première étude réalisée au cours de ce projet, a eu pour objectif de caractériser le microbiote intestinal de souris C57Bl/6 mâles soumises au modèle ABA. Une augmentation des Lactobacilles et de clostridium cocleatum appartenant au genre Clostridium, ainsi qu’une diminution de Burkholderiales ont été observé chez les animaux ABA. Par ailleurs, de nombreuses corrélations entre différents groupes bactériens et la prise alimentaire, le poids corporel ainsi que la composition corporelle ont été soulignées. Afin d’étudier le rôle de la présence du microbiote intestinal au cours du modèle ABA, nous avons, lors d’un deuxième travail, mis en place un protocole de déplétion par antibiothérapie. Pour cela nous avons comparé différents modes d’administration d’une solution d’antibiotiques à large spectre, par gavage oral une ou deux fois par jour ou par administration dans l’eau de boisson. Bien que ces trois modes provoque une très forte diminution des bactéries présentent au niveau fécal, l’administration une fois par jour induit une prolifération des Gammaprotéobactéries. Par conséquent, l’administration par eau de boisson ou gavage oral deux fois par jours apparaissent comme les procédures les mieux adaptées pour dépléter le microbiote intestinal. Lors de la troisième étude effectuée au cours de cette thèse, nous avons étudié la réponse au modèle ABA chez des souris C57Bl/6 mâles et femelles dont le microbiote intestinal a été déplété par antibiothérapie. Tout d’abord il a été montré que l’administration d’antibiotiques, induisait une augmentation de la masse grasse et une diminution de la masse maigre. Suite au modèle ABA les animaux déplétés présentaient une plus faible diminution de leur poids corporel. Ce phénomène était d’autant plus marqué chez les mâles, chez lesquels un comportement anxieux a également été souligné. Cette étude a donc permis de montrer une réponse sexe-dépendante à la déplétion du microbiote intestinal au cours du modèle ABAAnorexia nervosa (AN) is an eating disorder (ED) with female predominance, mainly characterised by a decrease of food intake leading to a severe body weight loss. Furthermore, psychiatric comorbidities are frequently observed in AN patients such as depression and anxiety. During the last decade, the role of microbiota-gut-brain axis in ED and anxiety-like behavior has emerged. Several studies reported gut microbiota dysbiosis in anorectic patients. Nevertheless, the pathophysiology of AN remains poorly understood. The aim of the present PhD thesis was to better understand the contribution of the gut microbiota in the regulation of gut-brain axis in the mouse model of anorexia "activity-based anorexia" (ABA). The ABA model combines spontaneous physical activity with a free running wheel access and a progressive limited food access. In a first study, we characterised the gut microbiota of C57Bl/6 male mice submitted to ABA model. We observed in ABA mice an increase of Lactobacillus and clostridium cocleatum belonging to genus of Clostridium, as well as a decrease of Burkholderiales. Interestingly, correlations between bacteria taxa and food intake, body weight and body composition have been observed. Then, we aimed to evaluate the response to ABA model of mice with gut microbial depletion. We thus compared in a second study different dosing and administration of large spectrum antibiotic treatments, either by oral gavages (once or twice a day) or by addition in drinking water. Although these three strategies led to a strong decrease of faecal bacteria, once day oral gavage induced proliferation of Gammaproteobacteria. Thus, antibiotics administration by oral gavage twice a day or in drinking water appear as the most appropriate modes to achieve gut microbiota depletion. In a third study, we then evaluated the response to ABA model of both male and female C57Bl/6 mice with antibiotic-induced microbiota depletion. Firstly, we observed that antibiotic administration led to an increase of fat mass and a decrease of lean mass. During the ABA model, gut microbiota-depleted mice exhibited a lower decrease of body weight compared to untreated ABA mice. In males, we also observed altered anxiety-like behavior in ABA mice with depleted gut microbiota. We thus showed that gut microbiota-depleted mice exhibited an altered response to ABA model in a sex-dependent manner. Finally, in order to decipher the underlying mechanisms, we focused on toll-like receptor 4 (TLR4), an endogenous receptor of lipopolysaccharides. Previous studies suggested TLR4 implication in the regulation of feeding and anxiety-like behaviors. To determine the involvement of intestinal TLR4, we submitted mice with intestinal epithelial TLR4 knockout to the ABA model. Again, we observed a sex-dependent response: a delayed and limited body weight loss in males and an increase of anxiety-like behavior in females. In conclusion, studies performed during this PhD thesis highlight the alterations and the role of gut microbiota in the activity-based anorexia model that appear to be sex-dependent
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Ritsou, Elena. "The role of CD4 and CXCR4 mediated apoptosis in T cell depletion during HIV-1 infection." Thesis, Open University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390903.
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Fávero, Michele Thaís. "Respostas cardiorrespiratórias promovidas pela ativação de receptores glutamatérgicos e purinérgicos no núcleo do trato solitário." Universidade Federal de São Carlos, 2012. https://repositorio.ufscar.br/handle/ufscar/1341.
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The central nervous system (CNS) has an important role in maintaining the composition and volume of body fluids for the appropriate tissue perfusion. An important area of the CNS that receives cardiorespiratory afferents is the nucleus of the solitary tract (NTS) that has several types of neurotransmitters, includingL-glutamate and adenosine 5'-triphosphate (ATP). Neuroendocrine changes that occur during sodium depletion could change glutamatergi c and purinergic neurotransmissions into the NTS. Thus, in this study, we investigated : 1) the effects of sodium depletion on cardiorespiratory responses before and after injections of L -glutamate and α,β-methyleneadenosine 5′-triphosphate (α,β-methyl ATP, a selective P2X purinergic receptor agonist) into the NTS of unanesthetized and sodium depleted rats; 2) the cardiorespiratory responses of the injection of α,β-methyl ATP before and after the blockade of P2 receptor purinergic antagonist with suramin (non-selective P2 purinergic receptor antagonist) into NTS of unanesthetized and normovolemic rats and 3) to describe the autonomic components involved with the cardiovascular responses after injection of α,β-methyl ATP into the NTS. Male Holtzman rats with a cannula implanted into the NTS and catheters inserted into the femoral artery and vein were used. Ventilation (VE) was measured by whole body plethysmograph method. In relation to objective 1, the cardiorespiratory parameters were measured in normovolemic (before sodium depletion), depleted (24 h after sodium depletion) and repleted rats (two hours after free access to 0.3 M NaCl and water). Sodium depletion was induced by the treatment with the diuretic furosemide (20 mg/kg of body weight) injected subcut aneously (s.c.) followed by 24 h of sodium -deficient diet. Sodium depletion did not modify baseline MAP (104 ± 4 mmHg, vs. normovolemic: 105 ± 4 mmHg) or HR (334 ± 20 bpm, vs. normovolemic: 379 ± 13 bpm) but increased the VE (708 ± 107 ml/min/kg, vs. normovolemic: 478 ± 60 ml/min/kg). This effect was due to increase on tidal volume (VT, 7 ± 0.6 ml/kg, vs. normovolemic: 5 ± 0.4 ml/kg) without effect on the respiratory frequency (fR, 99 ± 8 cpm, vs. normovolemic: 85 ± 6 cpm). In repleted rats, VE did not return to normal level (640 ± 33 ml/min/kg, vs. normovolemic: 478 ± 60 ml/min/kg). Unilateral injections of L-glutamate (1 and 5 nmol/100 nl) into the NTS produced pressor response (17 ± 3 and 36 ± 3 mmHg, respectively, vs. saline: 3 ± 1 mmHg), bradycardia (-130 ± 15 and -169 ± 10 bpm, respectively, vs. saline: -13 ± 6 bpm) and the hyperventilation (233 ± 44 and 495 ± 114 ml/min/kg, respectively, vs. saline: 32 ± 26 ml/min/kg). Sodium depletion reduced pressor responses (4 ± 3 mmHg and 13 ± 4 mmHg, respectively) and hyperventilation (-112 ± 112 and 7 ± 115 ml/min/kg, respectively) and did not change bradycardia (-116 ± 30 and -156 ± 18 bpm, respectively). Unilateral injections of α,β-methyl ATP (2 nmol/100 nl) into the NTS also produced pressor response (36 ± 5 mmHg, vs. saline: 3 ± 1 mmHg), bradycardia (-194 ± 18 bpm, vs. saline: -13 ± 6 bpm) and did not change VE (54 ± 96 ml/min/kg, vs. saline: 32 ± 26 ml/min/kg). Sodium depletion reduced pressor response (24 ± 5 mmHg), VE ( -147 ± 184 ml/min/kg) and did not change bradycardia (-168 ± 22 bpm). In relation to objective 2, the results showed that injection of α,β-methyl ATP (2 nmol/100 nl) into NTS produced pressor response (24 ± 4 mmHg e -187 ± 39 bpm, respectively) and these responses were reduced 15 min after injection of suramin into NTS ipsilateral (13 ± 2 mmHg e -80 ± 18 bpm). Injection of α,β-methyl ATP into NTS produced no significantly change in VE. In relation to objective 3, the results showed that injection of α,β-methyl ATP (2 nmol/100 nl) into NTS promote pressor and bradycardic response (32 ± 5 mmHg and -183 ± 21 bpm). The pre-treatment with the alpha1 -adrenoceptor antagonist prazosin (1 mg/kg bw, i.v.) attenuated the increase in MAP (+10 ± 3 mmHg) without changing the bradycardic response (-192 ± 21 bpm) evoked by injection of α,β-methyl ATP into NTS. The pre-treatment with the cholinergic muscarinic antagonist, methyl-atropine (1 mg/kg bw, i.v.) did not changed the pressor response (+31 ± 6 mmHg) and abolished the bradycardic response (+21 ± 6 bpm) induced by injection of α,β-methyl ATP into the NTS. The results suggest that neuroendocrine changes produced by sodium depletion (increased level of circulating ANG II, aldosterone and the desactivation of the volume receptors and baroreceptors) may change the glutamatergic and purinergic neurotransmissions into the NTS. Furthermore, activation of P2X receptors in the NTS activates both the sympathetic and parasympathetic nervous system to produce pressor and bradycardic responses, respectively, without changing ventilation
O sistema nervoso central (SNC) possui um papel fundamental na manutenção da composição e do volume dos líquidos corporais, para a adequada perfusão tecidual. Uma importante área do SNC que recebe aferências cardiorrespiratórias é o núcleo do trato solitário (NTS) que possui vários tipos de neurotransmissores, dentre eles o L-glutamato e adenosina-5´-trifosfato (ATP). Mudanças neuroendócrinas que ocorrem durante a depleção de sódio poderiam alterar as neurotransmissões glutamatérgica e purinérgica no NTS. Assim, neste estudo, tivemos 3 objetivos: 1) investigar os efeitos da depleção de sódio nas respostas cardiorrespiratórias antes e após a injeção de L-glutamato e α,β-metileno adenosina 5’ trifosfato (α,β-metil ATP, agonista seletivo de receptor purinérgico P2X) no NTS de ratos não anestesiados; 2) investigar as respostas cardiorrespiratórias à injeção de α,β-metil ATP no NTS antes e após o bloqueio dos receptores purinérgicos P2 com o suramin (antagonista não-seletivo de receptores P2) no NTS de ratos não anestesiados e normovolêmicos e 3) caracterizar os componentes autonômicos envolvidos nas respostas cardiovasculares após a injeção de α,β-metil ATP no NTS. Foram utilizados ratos Holtzman com cânulas implantadas no NTS e com cateter inserido na artéria e veia femoral. As medidas de ventilação (VE) foram obtidas pelo método de pletismografia de corpo inteiro. Com relação ao objetivo 1, os parâmetros cardiorrespiratórios foram medidos em ratos normovolêmicos (antes da depleção de sódio), depletados (24 h após a depleção de sódio) e ratos repletos (2 h após o livre acesso a NaCl 0,3 M e água). A depleção de sódio foi induzida pelo tratamento com o diurético furosemida (20 mg/Kg do peso corporal) injetado subcutaneamente (s.c.) acompanhado de uma dieta deficiente em sódio por 24 h. A depleção de sódio não modificou a PAM basal (104 ± 4 mmHg, vs. normovolêmicos: 105 ± 4 mmHg) nem a FC (334 ± 20 bpm, vs. normovolêmico: 379 ± 13 bpm) mas aumentou a VE (708 ± 107 ml/min/kg, vs. normovolêmico: 478 ± 60 ml/min/kg). Este efeito ocorreu devido a um aumento do volume corrente (VC, 7 ± 0,6 ml/kg, vs. normovolêmico: 5 ± 0,4 ml/kg) sem alterar a frequência respiratória (fR, 99 ± 8 cpm, vs. normovolêmicos: 85 ± 6 cpm). Em ratos repletos, a VE não retornou ao nível normal (640 ± 33 ml/min/kg vs. normovolêmico: 478 ± 60 ml/min/kg). Injeções unilaterais de Lglutamato (1 e 5 nmol/100 nl) no NTS produziu resposta pressora (17 ± 3 e 36 ± 3 mmHg, respectivamente, vs. salina: 3 ± 1 mmHg), bradicardia (-130 ± 15 e -169 ± 10 bpm, respectivamente, vs. salina: -13 ± 6 bpm) e hiperventilação (233 ± 44 e 495 ± 114 ml/min/kg, respectivamente, vs. salina: 32 ± 26 ml/min/kg). A depleção de sódio reduziu a resposta pressora (4 ± 3 mmHg e 13 ± 4 mmHg, respectivamente) e hiperventilação (-112 ± 112 e 7 ± 115 ml/min/kg, respectivamente) e não alterou a bradicardia (-116 ± 30 e -156 ± 18 bpm, respectivamente). Injeção unilateral de α,β-metil ATP (2 nmol/100 nl) no NTS também produziu resposta pressora (36 ± 5 mmHg, vs. salina: 3 ± 1 mmHg), bradicardia (- 194 ± 18 bpm, vs. salina: -13 ± 6 bpm) e não modificou a VE (54 ± 96 ml/min/kg, vs. salina: 32 ± 26 ml/min/kg). A depleção de sódio reduziu a resposta pressora (24 ± 5 mmHg), a VE (-147 ± 184 ml/min/kg) e não alterou a bradicardia (-168 ± 22 bpm). Com relação ao objetivo 2, os resultados mostraram que a injeção de α,β-metil ATP (2 nmol/100 nl) no NTS promoveu resposta pressora e bradicárdica (24 ± 4 mmHg e -187 ± 39 bpm, respectivamente) e estas respostas foram reduzidas aos 15 minutos após a injeção de suramin no NTS ipsilateral (13 ± 2 mmHg e -80 ± 18 bpm). A injeção de α,β-metil ATP no NTS não promoveu alterações significativas na VE. Com relação ao objetivo 3, os resultados mostraram que as injeções de α,β-metil ATP (2 nmol/100 nl) no NTS promoveu resposta pressora e bradicardia (+32 ± 5 mmHg e -183 ± 21 bpm). O pré-tratamento com o antagonista de receptor alfa-1 adrenérgico, prazosin (1 mg/kg de peso corporal, i.v.), atenuou o aumento da PAM (+10 ± 3 mmHg) sem alterar a bradicardia (-192 ± 21 bpm) provocada pela injeção de α,β-metil-ATP no NTS e o pré-tratamento com o antagonista colinérgico muscarínico, metil-atropina (1 mg/kg de peso corporal, i.v.) não alterou a resposta pressora (+31 ± 6 mmHg) e aboliu a bradicardia (+21 ± 6 bpm) induzida pela injeção de α,β-metil ATP no NTS. Os resultados sugerem que alterações neuroendócrinas produzidas pela depleção de sódio (aumento dos níveis de ANG II e aldosterona circulantes e a desativação de receptores de volume e dos barorreceptores) podem alterar as neurotransmissões glutamatérgica e purinérgica no NTS. Além disso, a ativação dos receptores purinérgicos P2X no NTS ativa simultaneamente o sistema nervoso simpático e parassimpático para produzir respostas pressora e bradicárdica, respectivamente, sem alterar a ventilação pulmonar.
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Engelschalt, Vivienne. "Mechanismen der antikörpervermittelten T-Zell-Depletion in vivo im Maus-Modell." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2010. http://dx.doi.org/10.18452/16234.
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Monoklonale Antikörper (mAk) werden bereits erfolgreich zur therapeutischen Depletion verschiedener Zellpopulationen in vivo verwendet, die Mechanismen der Depletion sind jedoch unklar geblieben. In dieser Arbeit wurden im Mausmodell die molekularen Grundlagen der CD4+ T-Zelldepletion (CD4 TZD) nach einmaliger Gabe (i.p.) von 100 µg des anti-CD4-mAk YTS191.1 untersucht. Dabei konnte eine starke Korrelation zwischen Depletion und der Modulation des CD4-Moleküls von der Oberfläche beobachtet werden. Gleichzeitig zeigten sich organabhängige Unterschiede, sowohl im zeitlichen Verlauf, als auch in der Effizienz der Depletion. Im Thymus konnten weder Depletion noch Modulation detektiert werden, in Milz und Lymphknoten (Lk) war die CD4 TZD nach starker CD4-Modulation bereits nach 48 h mit 80-90 % maximal, in den Peyer-Plaques jedoch niedriger und verzögert (50-60 % nach 72 h). Anhand C3-defizienter Mäuse konnte ferner kein wesentlicher Beitrag von Komplement an der CD4 TZD beobachtet werden. Im Gegensatz dazu konnte durch die Verwendung verschiedener FcGamma-Rezeptor (FcGammaR)-defizienter Mäuse (FcGammaRI, FcGammaRII, FcGammaRIII, FcGammaRI/III und FcRGamma) wie auch durch die Blockade des FcGammaRIV eine starke, zudem organabhängige Beteiligung von FcGammaR an der CD4 TZD gezeigt werden. Während in der Milz die CD4 TZD von FcGammaRIV vermittelt wurde, waren in den Lk und Peyer-Plaques FcGammaRI/III involviert. Diese Befunde korrelierten mit der starken Expression von FcGammaRIV in Milz, Lunge, Darm, Niere und Leber, während in den Lk nur eine schwache und in Thymus und Peyer-Plaques keine Expression detektiert werden konnte. Innerhalb der Milz konnten erstmalig F4/80hoch Makrophagen als FcGammaRIV+ identifiziert und somit als potenzielle Effektorzellen der CD4 TZD bestimmt werden. Der direkte Vergleich der Depletion von CD4+ T-Zellen mit der Depletion von ICOS+ T-Zellen verdeutlichte darüber hinaus, dass die Effizienz der Zelldepletion nicht nur von den Eigenschaften des verwendeten mAk, sondern auch von denen des Zielmoleküls abhängig ist.Monoclonal antibodies (mAb) are efficiently used for the therapeutic depletion of various cells in vivo yet the mechanisms of depletion are still unclear. In this work, the molecular principles of CD4+ T cell depletion (CD4 Tcd) by a single application of 100 µg of the anti-CD4 mAb YTS191.1.1 were investigated in the mouse. A strong correlation between the depletion and the surface modulation of the CD4 molecule could be observed. At the same time, organ-dependent differences in the kinetics as well as in the efficiency of depletion could be detected. In the thymus, neither modulation nor depletion were detectable. In the spleen and the lymph nodes (Ln), the modulation was strong and the depletion was maximal (80-90%) 48 h after mAb treatment. Interestingly, both modulation and depletion were decreased and delayed (50-60% after 72 h) in the Peyer`s patches. By using C3-deficient mice, no major contribution of complement to the CD4 Tcd was seen. On the contrary, with the help of different FcGamma-receptor (FcGammaR)-deficient mice (FcGammaRI, FcGammaRII, FcGammaRIII, FcGammaRI/III, and FcRGamma) and through the blockade of FcGammaRIV, a strong organ dependent involvement of FcGammaR could be shown. While the depletion in the spleen was clearly dependent on FcGammaRIV, in the Ln and the Peyer`s patches, FcGammaRI/III were involved. These findings correlated with the strong expression of FcGammaRIV in the spleen, the lung, the colon, the kidney, and the liver, while in the Ln the expression was weak and undetectable in the thymus and the Peyer`s patches. For the first time, F4/80high macrophages in the spleen could be identified as also being FcGammaRIV+, and are therfore considered as the potential effector cells of the CD4 Tcd. The direct comparison of the depletion of T cells via CD4 or ICOS pointed out that the target cell depletion is not only dependent on the properties of the mAb used, but also on those of the target molecule.
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Tavares, Lucas Alves. "O envolvimento da proteína adaptadora 1 (AP-1) no mecanismo de regulação negativa do receptor CD4 por Nef de HIV-1." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/17/17136/tde-06012017-113215/.
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O Vírus da Imunodeficiência Humana (HIV) é o agente etiológico da Síndrome da Imunodeficiência Adquirida (AIDS). A AIDS é uma doença de distribuição mundial, e estima-se que existam atualmente pelo menos 36,9 milhões de pessoas infectadas com o vírus. Durante o seu ciclo replicativo, o HIV promove diversas alterações na fisiologia da célula hospedeira a fim de promover sua sobrevivência e potencializar a replicação. A rápida progressão da infecção pelo HIV-1 em humanos e em modelos animais está intimamente ligada à função da proteína acessória Nef. Dentre as diversas ações de Nef está a regulação negativa de proteínas importantes na resposta imunológica, como o receptor CD4. Sabe-se que esta ação resulta da indução da degradação de CD4 em lisossomos, mas os mecanismos moleculares envolvidos ainda são totalmente elucidados. Nef forma um complexo tripartite com a cauda citosólica de CD4 e a proteína adaptadora 2 (AP-2), em vesículas revestidas por clatrina nascentes, induzindo a internalização e degradação lisossomal de CD4. Pesquisas anteriores demonstraram que o direcionamento de CD4 aos lisossomos por Nef envolve a entrada do receptor na via dos corpos multivesiculares (MVBs), por um mecanismo atípico, pois, embora não necessite da ubiquitinação de carga, depende da ação de proteínas que compõem os ESCRTs (Endosomal Sorting Complexes Required for Transport) e da ação de Alix, uma proteína acessória da maquinaria ESCRT. Já foi reportado que Nef interage com subunidades dos complexos AP-1, AP-2, AP-3 e Nef não parece interagir com subunidades de AP-4 e AP-5. Entretanto, o papel da interação de Nef com AP-1 e AP-3 na regulação negativa de CD4 ainda não está totalmente elucidado. Ademais, AP-1, AP-2 e AP-3 são potencialmente heterogêneos devido à existência de isoformas múltiplas das subunidades codificadas por diferentes genes. Todavia, existem poucos estudos para demonstrar se as diferentes combinações de isoformas dos APs são formadas e se possuem propriedades funcionais distintas. O presente trabalho procurou identificar e caracterizar fatores celulares envolvidos na regulação do tráfego intracelular de proteínas no processo de regulação negativa de CD4 induzido por Nef. Mais especificamente, este estudo buscou caracterizar a participação do complexo AP-1 na modulação negativa de CD4 por Nef de HIV-1, através do estudo funcional das duas isoformas de ?-adaptina, subunidades de AP-1. Utilizando a técnica de Pull-down demonstramos que Nef é capaz de interagir com ?2. Além disso, nossos dados de Imunoblot indicaram que a proteína ?2-adaptina, e não ?1-adaptina, é necessária no processo de degradação lisossomal de CD4 por Nef e que esta participação é conservada para degradação de CD4 por Nef de diferentes cepas virais. Ademais, por citometria de fluxo, o silenciamento de ?2, e não de ?1, compromete a diminuição dos níveis de CD4 por Nef da membrana plasmática. A análise por imunofluorêsncia indireta também revelou que a diminuição dos níveis de ?2 impede a redistribuição de CD4 por Nef para regiões perinucleares, acarretando no acúmulo de CD4, retirados por Nef da membrana plasmática, em endossomos primários. A depleção de ?1A, outra subunidade de AP-1, acarretou na diminuição dos níveis celulares de ?2 e ?1, bem como, no comprometimento da eficiente degradação de CD4 por Nef. Além disso, foi possível observar que, ao perturbar a maquinaria ESCRT via super-expressão de HRS (uma subunidade do complexo ESCRT-0), ocorreu um acumulo de ?2 em endossomos dilatados contendo HRS-GFP, nos quais também detectou-se CD4 que foi internalizado por Nef. Em conjunto, os resultados indicam que ?2-adaptina é uma importante molécula para o direcionamento de CD4 por Nef para a via ESCRT/MVB, mostrando ser uma proteína relevante no sistema endo-lisossomal. Ademais, os resultados indicaram que as isoformas ?-adaptinas não só possuem funções distintas, mas também parecem compor complexos AP-1 com diferentes funções celulares, já que apenas a variante AP-1 contendo ?2, mas não ?1, participa da regulação negativa de CD4 por Nef. Estes estudos contribuem para o melhor entendimento dos mecanismos moleculares envolvidos na atividade de Nef, que poderão também ajudar na melhor compreensão da patogênese do HIV e da síndrome relacionada. Em adição, este trabalho contribui para o entendimento de processos fundamentais da regulação do tráfego de proteínas transmembrana no sistema endo-lisossomal.The Human Immunodeficiency Virus (HIV) is the etiologic agent of Acquired Immunodeficiency Syndrome (AIDS). AIDS is a disease which has a global distribution, and it is estimated that there are currently at least 36.9 million people infected with the virus. During the replication cycle, HIV promotes several changes in the physiology of the host cell to promote their survival and enhance replication. The fast progression of HIV-1 in humans and animal models is closely linked to the function of an accessory protein Nef. Among several actions of Nef, one is the most important is the down-regulation of proteins from the immune response, such as the CD4 receptor. It is known that this action causes CD4 degradation in lysosome, but the molecular mechanisms are still incompletely understood. Nef forms a tripartite complex with the cytosolic tail of the CD4 and adapter protein 2 (AP-2) in clathrin-coated vesicles, inducing CD4 internalization and lysosome degradation. Previous research has demonstrated that CD4 target to lysosomes by Nef involves targeting of this receptor to multivesicular bodies (MVBs) pathway by an atypical mechanism because, although not need charging ubiquitination, depends on the proteins from ESCRTs (Endosomal Sorting Complexes Required for Transport) machinery and the action of Alix, an accessory protein ESCRT machinery. It has been reported that Nef interacts with subunits of AP- 1, AP-2, AP-3 complexes and Nef does not appear to interact with AP-4 and AP-5 subunits. However, the role of Nef interaction with AP-1 or AP-3 in CD4 down-regulation is poorly understood. Furthermore, AP-1, AP-2 and AP-3 are potentially heterogeneous due to the existence of multiple subunits isoforms encoded by different genes. However, there are few studies to demonstrate if the different combinations of APs isoforms are form and if they have distinct functional properties. This study aim to identify and characterize cellular factors involved on CD4 down-modulation induced by Nef from HIV-1. More specifically, this study aimed to characterize the involvement of AP-1 complex in the down-regulation of CD4 by Nef HIV-1 through the functional study of the two isoforms of ?-adaptins, AP-1 subunits. By pull-down technique, we showed that Nef is able to interact with ?2. In addition, our data from immunoblots indicated that ?2- adaptin, not ?1-adaptin, is required in Nef-mediated targeting of CD4 to lysosomes and the ?2 participation in this process is conserved by Nef from different viral strains. Furthermore, by flow cytometry assay, ?2 depletion, but not ?1 depletion, compromises the reduction of surface CD4 levels induced by Nef. Immunofluorescence microscopy analysis also revealed that ?2 depletion impairs the redistribution of CD4 by Nef to juxtanuclear region, resulting in CD4 accumulation in primary endosomes. Knockdown of ?1A, another subunit of AP-1, resulted in decreased cellular levels of ?1 and ?2 and, compromising the efficient CD4 degradation by Nef. Moreover, upon artificially stabilizing ESCRT-I in early endosomes, via overexpression of HRS, internalized CD4 accumulates in enlarged HRS-GFP positive endosomes, where co-localize with ?2. Together, the results indicate that ?2-adaptin is a molecule that is essential for CD4 targeting by Nef to ESCRT/MVB pathway, being an important protein in the endo-lysosomal system. Furthermore, the results indicate that ?-adaptins isoforms not only have different functions, but also seem to compose AP-1 complex with distinct cell functions, and only the AP-1 variant comprising ?2, but not ?1, acts in the CD4 down-regulation induced by Nef. These studies contribute to a better understanding on the molecular mechanisms involved in Nef activities, which may also help to improve the understanding of the HIV pathogenesis and the related syndrome. In addition, this work contributes with the understanding of primordial process regulation on intracellular trafficking of transmembrane proteins.
Books on the topic "Receptor depletion"
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Cheung, Hermia. Effect of dopamine depletion on D1 receptor binding in rat brain; and metabolism studies of D1 agonist R-[11C]SKF 82957 and phosphodiesterase-4 inhibitor R-[11C}rolipram. Ottawa: National Library of Canada, 2003.
Find full textBook chapters on the topic "Receptor depletion"
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Cheng, Kwong Tai, Hwei Ling Ong, Xibao Liu, and Indu S. Ambudkar. "Contribution of TRPC1 and Orai1 to Ca2+ Entry Activated by Store Depletion." In Transient Receptor Potential Channels, 435–49. Dordrecht: Springer Netherlands, 2010. http://dx.doi.org/10.1007/978-94-007-0265-3_24.
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Kitic, Maja, Peter See, Julia Bruttger, Florent Ginhoux, and Ari Waisman. "Novel Microglia Depletion Systems: A Genetic Approach Utilizing Conditional Diphtheria Toxin Receptor Expression and a Pharmacological Model Based on the Blocking of Macrophage Colony-Stimulating Factor 1 Receptor." In Microglia, 217–30. New York, NY: Springer New York, 2019. http://dx.doi.org/10.1007/978-1-4939-9658-2_16.
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Caetano Crowley, Fabiana A., Bryan Heit, and Stephen S. G. Ferguson. "Super-Resolution Imaging of G Protein-Coupled Receptors Using Ground State Depletion Microscopy." In Methods in Molecular Biology, 323–36. New York, NY: Springer New York, 2019. http://dx.doi.org/10.1007/978-1-4939-9121-1_18.
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Abi-Dargham, Anissa, Larry Kegeles, Mark Slifstein, and Marc Laruelle. "Chapter 24 Antipsychotic-Induced Changes in Striatal D2 Receptors in Schizophrenia: In Vivo Evidence from Dopamine Depletion Studies." In Staging Neuropsychiatric Disorders, 259–64. Boston, MA: Springer US, 2011. http://dx.doi.org/10.1007/978-1-4614-0785-0_24.
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Abi-Dargham, Anissa, Larry Kegeles, Mark Slifstein, and Marc Laruelle. "Chapter 27 Antipsychotic-Induced Changes in Striatal D2 Receptors in Schizophrenia: In Vivo Evidence from Dopamine Depletion Studies." In Staging Neuropsychiatric Disorders, 293–98. New York, NY: Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4614-7264-3_27.
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Peters, Maximilian, Ben Katz, Shaya Lev, Rachel Zaguri, Rita Gutorov, and Baruch Minke. "Depletion of Membrane Cholesterol Suppresses Drosophila Transient Receptor Potential-Like (TRPL) Channel Activity." In Sterol Regulation of Ion Channels, 233–54. Elsevier, 2017. http://dx.doi.org/10.1016/bs.ctm.2017.05.005.
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Bernard, Véronique, Corinne Brana, Isabel Liste, Oksana Lockridge, and Bertrand Bloch. "Dramatic depletion of cell surface muscarinic receptor due to limited delivery from intracytoplasmic stores in neurons of acetylcholinesterase-deficient mice." In Cholinergic Mechanisms, 477–79. CRC Press, 2004. http://dx.doi.org/10.3109/9780203493878-71.
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Toro-Urrego, Nicolas, Marco Avila-Rodriguez, María Inés Herrera, Andrea Aguilar, Lucas Udovin, and Juan P. Luaces. "Neuroactive Steroids in Hypoxic–Ischemic Brain Injury: Overview and Future Directions." In Neuroprotection - New Approaches and Prospects. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.93956.
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Hypoxic–ischemic brain injury is a number one cause of long-term neurologic disability and death worldwide. This public health burden is mainly characterized by a decrease in oxygen concentration and blood flow to the tissues, which lead to an inefficient supply of nutrients to the brain. This condition induces cell death by energy depletion and increases free radical generation and inflammation. Hypoxic–ischemic brain injury may occur in ischemic-stroke and over perinatal asphyxia, being both leading causes of morbidity in adults and children, respectively. Currently, there are no effective pharmaceutical strategies to prevent the triggering of secondary injury cascades, including oxidative stress and metabolic dysfunction. Neuroactive steroids like selective estrogen receptor modulators, SERMs, and selective tissue estrogenic activity regulators, STEARs, exert several neuroprotective effects. These encompass mitochondrial survival, a decrease in reactive oxygen species, and maintenance of cell viability, among others. In this context, these neurosteroids constitute promising molecules, which could modify brain response to injury. Here we show an updated overview of the underlying mechanisms of hypoxic–ischemic brain injury. We also highlight the neuroprotective effects of neurosteroids and their future directions.
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"MAGNESIUM DEPLETION INDUCES HYPERCALCEMIA IN D3 REPLETE AND UP REGULATION OF THE INTESTINAL l,25(OH)2D3 RECEPTOR IN DDEPLETED RATS." In Vitamin D, 718–19. De Gruyter, 1991. http://dx.doi.org/10.1515/9783110850345-244.
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Saikarthik, Jayakumar, Ilango Saraswathi, and Abdulrahman A. Al-Atram. "Does COVID-19 Affect Adult Neurogenesis? A Neurochemical Perspective." In Recent Advances in Neurochemistry [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.101179.
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COVID-19 has been found to cause neuropsychiatric symptoms which indicate brain involvement. SARS-CoV-2 may enter the brain by damaging and penetrating olfactory mucosa and via other possible routes like damaged blood–brain barrier, and hematologic spread. With SARS-CoV-2 having a higher affinity to ACE2 receptors, brain regions that have higher ACE2 receptors like the hippocampus, are more vulnerable to the effect of the viral invasion. In addition, immune cell activation, an important feature of COVID-19, leads to cytokine storm which causes neurotoxicity, neuroinflammation, and neurodegeneration. Impaired adult neurogenesis is related to many psychiatric disorders including depression, bipolar disorder, anxiety disorder, schizophrenia, and PTSD. It is known to be related to the depletion of neurotransmitters, dopamine, serotonin, norepinephrine, GABA, and glutamate which play a major role in adult neurogenesis. A recent study reveals that SSRI which acts by increasing serotonin is proven beneficial in COVID-19 patients. Thus, the current chapter will discuss the impact of COVID-19 on adult neurogenesis with emphasis on the role of ACE2 and neurotransmitters.
Conference papers on the topic "Receptor depletion"
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Gossage, David L., Michel Laviolette, Gail M. Gauvreau, Richard Leigh, Roland Kolbeck, Yanping Wu, Laura Richman, and Nestor A. Molfino. "Depletion Of Airway Eosinophils By Benralizumab An Anti-IL5 Receptor Alpha Monoclonal Antibody." In American Thoracic Society 2012 International Conference, May 18-23, 2012 • San Francisco, California. American Thoracic Society, 2012. http://dx.doi.org/10.1164/ajrccm-conference.2012.185.1_meetingabstracts.a3961.
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O'Brien, Sarah A., Katarzyna Skrzypczynska, Jessica Orf, Brian Belmontes, Hong Tan, Daniel Lu, Ian Driver, and Jackson Egen. "Abstract 2803: CSF-1 receptor-mediated macrophage depletion can induce immunomodulatory resistance mechanisms in murine tumor models." In Proceedings: AACR Annual Meeting 2019; March 29-April 3, 2019; Atlanta, GA. American Association for Cancer Research, 2019. http://dx.doi.org/10.1158/1538-7445.sabcs18-2803.
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O'Brien, Sarah A., Katarzyna Skrzypczynska, Jessica Orf, Brian Belmontes, Hong Tan, Daniel Lu, Ian Driver, and Jackson Egen. "Abstract 2803: CSF-1 receptor-mediated macrophage depletion can induce immunomodulatory resistance mechanisms in murine tumor models." In Proceedings: AACR Annual Meeting 2019; March 29-April 3, 2019; Atlanta, GA. American Association for Cancer Research, 2019. http://dx.doi.org/10.1158/1538-7445.am2019-2803.
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Fidanza, Mario, Sumin Jo, Arnawaz Bashir, Stephan A. Grupp, Alix E. Seif, and Gregor S. Reid. "Abstract B33: Toll-like receptor ligands delay acute lymphoblastic leukemia onset via depletion of pre-leukemic cells." In Abstracts: AACR Special Conference: Pediatric Cancer at the Crossroads: Translating Discovery into Improved Outcomes; November 3-6, 2013; San Diego, CA. American Association for Cancer Research, 2014. http://dx.doi.org/10.1158/1538-7445.pedcan-b33.
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Achyut, B. R., David A. Bader, Hannah H. Yan, Chaoyang Li, Yanli Pang, and Li Yang. "Abstract 3969: Stromal depletion of transforming growth factor receptor 2 promotes the development of forestomach squamous cell carcinoma." In Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC. American Association for Cancer Research, 2010. http://dx.doi.org/10.1158/1538-7445.am10-3969.
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Skrzypczynska, Katarzyna M., Sarah A. O'Brien, Brian Belmontes, Hong Tan, Jessica Orf, Daniel Lu, Ian Driver, and Jackson G. Egen. "Abstract A71: Resistance mechanisms limiting the immunostimulatory and antitumor activity of anti-CSF-1 receptor-mediated macrophage depletion." In Abstracts: AACR Special Conference on Tumor Immunology and Immunotherapy; November 27-30, 2018; Miami Beach, FL. American Association for Cancer Research, 2020. http://dx.doi.org/10.1158/2326-6074.tumimm18-a71.
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Scharf, R. E., M. Stockschläder, H. J. Reimers, and W. Schneider. "THE REDUCED CAPACITY OF THROMBOXANE FORMATION IN THROMBIN-PREACTIVATED PLATELETS IS NOT CAUSED BY DEPLETION OF THEIR ARACHIDONIC ACID POOL." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643393.
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Thromboxane (TX) synthesis of washed human platelets pretreated with high concentrations of thrombin (0.5-2.0 U/ml) for 20 sec is significantly reduced upon further thrombin stimulation. Compared to controls (tyrode-pretreated platelets), thrombin-preactivated platelets recover normal TX synthesis following exposure to exogenous arachidonic acid (AA) indicating that short-time thrombin treatment does not inactivate platelet cyclooxygenase or TX synthetase (Blood 63: 858, 1984). To evaluate whether the reduced TX synthesis upon -the second thrombin exposure is due to depletion of their AA precursor pool, thrombin-pretreated platelets and tyrode-pretreated platelets (5×108/ml) were resuspended in autologous ACD plasma and incubated at 37°C with 0.2 μCi 14C-AA (20 μM) for 60 to 90 min in the presence of PGE1 (10 μM). Mean platelet uptake of 14C-AA (disappearance of radioactivity from the supernatant) was 12+3 nmoles AA/109 platelets and did not differ significantly between thrombin-pretreated platelets and controls. Thrombin-pretreated platelets released 10% or 4.5% of their 14c-activity upon further exposure to thrombin (2 U/ml) or collagen (8 μg/ml), respectively. The release from control platelets (15% with thrombin, 6.5% with collagen) did not differ from that of thrombin-pretreated platelets. However, even after incubation in ACD plasma, thrombin-pretreated platelets continued to form significantly less TXB2 (5.0±1.6 nmoles/109 platelets) than controls (9.7±2.2 nmoles/109 platelets, p< 0.05). These data indicate that the reduced capacity of thrombin-pretreated platelets is due neither to a depletion of the endogenous AA pool nor to an inactivation of cyclooxygenase or TX synthetase. The reduced TX synthesis capacity may be caused by a modification, destruction or desensitization of the platelet thrombin receptor as a consequence of the preceding thrombin stimulation.
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Wachtfogel, Yanina T., Peter C. Harpel, L. Henry Edmunds, and Robert W. Colman. "FORMATION OF Cl -Cl INHIBITOR AND KALLIKREIN-Cl INHIBITOR COMPLEXES DURING CARDIOPULMONARY BYPASS." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1642900.
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Cardiopulmonary bypass prolongs bleeding time and increases postoperative blood loss. Contact of blood with synthetic surfaces during extracorporeal circulation leads to major qualitative and quantitative alterations in both platelets and neutrophils. Activation of platelets results in thrombocytopenia, decreased sensitivity of platelets to aggregating agents, decreased alpha2-adrenergic and fibrinogen receptors, secretion of thromboxane B2, and depletion of alpha-granule protein contents. Neutrophils,under similar conditions, have also been shown to release their specific granule protein, lactoferrin, and their azurophilic granule enzyme, elastase.We now investigate whether the classical complement, contact, or fibrinolytic pathways have been activated as potential sources of neutrophil agonists. Employing enzyme-linked immunosorbent “sandwich” assays specific for Cl -Cl inhibitor and kalli-krein-Cl inhibitor complexes respectively, we found that plasma levels of both of these formed complexes increased 2fold after clinical cardiopulmonary bypass was completed and reverted to baseline within 24 hours post-operatively. Since these complexes are cleared iji vivo, we investigated their plasma levels during jLn vitro simulated extracorporeal circulation. Over a period of 2 hours, Cl -Cl inhibitor complexes rose from a baseline of 2 + InM to 21 + 2 nM and kalli-krein-Cl inhibitor complexes rose from 2+1 nM to 25 + 5 nM. However, there was no evidence of either in vivo or vitro plasmin-alpha plasmin inhibitor complex formation. These results indicate that activation of the classical pathway of complement and the contact system in plasma may be associated with neutrophil activation seen during clinical cardiopulmonary bypass.
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Gastaldello, Gabriel Henrique, Amanda Rodrigues Correia Frota Gomes, Bruna Belone Garcia, Damiana Gianotto Pires, and Cristiane Tefé Sillva. "Pathogenesis and clinical aspects involved in stroke associated with COVID-19: A literature review." In XIII Congresso Paulista de Neurologia. Zeppelini Editorial e Comunicação, 2021. http://dx.doi.org/10.5327/1516-3180.611.
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Introduction: Currently, an increasing number of studies point to the prevalence of neurological manifestations associated with COVID-19, including stroke. Although the pathophysiology is not completely understood, the infection induces a prothrombotic state stimulate by high levels of factor VIII, fibrinogen and Ddimer. In this sense, high mortality (44,2%) is a challenging context and identify influences of clinical and morphological aspects the outcome of these patients. Design and setting: Literature review conduced in Barão de Mauá University Center, Ribeirão Preto-SP. Objective: Clarifying aspects involved in the pathogenesis and clinical manifestations in patients with COVID-19 and Stroke. Methods: The primary databases utilized to retrieve the salient medical literature presented in this review were Scielo and Pubmed. The search terms, included “stroke”, “SARS-CoV”, “covid-19”. Discussion: Ischemic stroke was the most common subtype found associated with multiple infarctions and cryptogenic etiology. The mechanisms are multifactorial, including conventional pathways stimulated by the pathogen or direct action. Called “sepsis coagulopathy”, activation of the coagulation pathway associated with viral invasion of endothelial cells and excessive release of cytokines causes a prothrombotic state. Hemorrhagic stroke is less common. It is believed that the affinity of SARS-coV- 2 for ACE2 (angiotensinconverting enzyme 2) receptors could directly damage intracranial arteries, causing rupture, associated with fibrinogen depletion and massive release of cytokines and proteases. Conclusion: Individuals affected by COVID-19 that are affected by stroke face more severe conditions and worse associated outcomes. Thus, understanding the pathophysiology and clinical aspects brings greater effectiveness in the care of these individuals and lower mortality.
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Sharma, Naveen, and James P. Allison. "Abstract B143: Fc gamma receptor IV mediated depletionof tumor infiltrating regulatory T cells by anti-CTLA4 antibody is promoted byTLR1/2 agonist and hence its efficacy in anti-tumor combination therapy." In Abstracts: Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; September 25-28, 2016; New York, NY. American Association for Cancer Research, 2016. http://dx.doi.org/10.1158/2326-6066.imm2016-b143.
Full textReports on the topic "Receptor depletion"
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Savaldi-Goldstein, Sigal, and Todd C. Mockler. Precise Mapping of Growth Hormone Effects by Cell-Specific Gene Activation Response. United States Department of Agriculture, December 2012. http://dx.doi.org/10.32747/2012.7699849.bard.
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Plant yield largely depends on a complex interplay and feedback mechanisms of distinct hormonal pathways. Over the past decade great progress has been made in elucidating the global molecular mechanisms by which each hormone is produced and perceived. However, our knowledge of how interactions between hormonal pathways are spatially and temporally regulated remains rudimentary. For example, we have demonstrated that although the BR receptor BRI1 is widely expressed, the perception of BRs in epidermal cells is sufficient to control whole-organ growth. Supported by additional recent works, it is apparent that hormones are acting in selected cells of the plant body to regulate organ growth, and furthermore, that local cell-cell communication is an important mechanism. In this proposal our goals were to identify the global profile of translated genes in response to BR stimulation and depletion in specific tissues in Arabidopsis; determine the spatio-temporal dependency of BR response on auxin transport and signaling and construct an interactive public website that will provide an integrated analysis of the data set. Our technology incorporated cell-specific polysome isolation and sequencing using the Solexa technology. In the first aim, we generated and confirmed the specificity of novel transgenic lines expressing tagged ribosomal protein in various cell types in the Arabidopsis primary root. We next crossed these lines to lines with targeted expression of BRI1 in the bri1 background. All lines were treated with BRs for two time points. The RNA-seq of their corresponding immunopurified polysomal RNA is nearly completed and the bioinformatic analysis of the data set will be completed this year. Followed, we will construct an interactive public website (our third aim). In the second aim we started revealing how spatio-temporalBR activity impinges on auxin transport in the Arabidopsis primary root. We discovered the unexpected role of BRs in controlling the expression of specific auxin efflux carriers, post-transcriptionally (Hacham et al, 2012). We also showed that this regulation depends on the specific expression of BRI1 in the epidermis. This complex and long term effect of BRs on auxin transport led us to focus on high resolution analysis of the BR signaling per se. Taking together, our ongoing collaboration and synergistic expertise (hormone action and plant development (IL) and whole-genome scale data analysis (US)) enabled the establishment of a powerful system that will tell us how distinct cell types respond to local and systemic BR signal. BR research is of special agriculture importance since BR application and BR genetic modification have been shown to significantly increase crop yield and to play an important role in plant thermotolerance. Hence, our integrated dataset is valuable for improving crop traits without unwanted impairment of unrelated pathways, for example, establishing semi-dwarf stature to allow increased yield in high planting density, inducing erect leaves for better light capture and consequent biomass increase and plant resistance to abiotic stresses.