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Статті в журналах з теми "Protéines MFS":
Beugré, Martine Manéhonon, François Kouakou Yao Konan, Salomé Edwige Sopie Yapo, Eugène Kouakou Konan, and Justin Yatty Kouadio. "Effet du temps de chauffage des graines de palmier à huile (Elaeis guineensis Jacq.) sur quelques métabolites au cours du processus de la germination." International Journal of Biological and Chemical Sciences 13, no. 7 (February 12, 2020): 3202–13. http://dx.doi.org/10.4314/ijbcs.v13i7.19.
Imaizumi, Hugo, Flávio Augusto Portela Santos, Alexandre Vaz Pires, and Sérgio de Oliveira Juchem. "Fontes protéicas e de amido com diferentes degradabilidades ruminais para alimentar vacas leiteiras." Pesquisa Agropecuária Brasileira 41, no. 9 (September 2006): 1413–20. http://dx.doi.org/10.1590/s0100-204x2006000900010.
Backes, Alfredo Acosta, Luis Maria Bonnecarrère Sanchez, and Maria Beatriz Fernandes Gonçalves. "Desempenho de Novilhos Santa Gertrudis Confinados Submetidos a Dietas com Diferentes Fontes Protéicas e Silagem de Milho, com ou sem Inoculante." Revista Brasileira de Zootecnia 30, no. 6 suppl (December 2001): 2121–25. http://dx.doi.org/10.1590/s1516-35982001000800022.
Ruiz Júnior, Raul Lopes, Lídia Raquel de Carvalho, and Antonio José Maria Cataneo. "Crescimento pulmonar compensatório (CPC): massa corpórea, conteúdo protéico e massa pulmonares em ratos subnutridos trilobectomizados." Acta Cirurgica Brasileira 19, no. 2 (April 2004): 146–52. http://dx.doi.org/10.1590/s0102-86502004000200012.
Ribeiro, Glauco Mora, Alexandre Amstalden Moraes Sampaio, Alexandre Rodrigo Mendes Fernandes, Wignez Henrique, Atushi Sugohara, and Ana Carolina Amorim. "Efeito da fonte protéica e do processamento físico do concentrado sobre a terminação de bovinos jovens confinados e o impacto ambiental dos dejetos." Revista Brasileira de Zootecnia 36, no. 6 suppl (December 2007): 2082–91. http://dx.doi.org/10.1590/s1516-35982007000900019.
Paziani, Solidete de Fátima, Telma Teresinha Berchielli, and Pedro de Andrade. "Digestibilidade e degradabilidade de rações à base de milho desintegrado com palha e sabugo em diferentes graus de moagem." Revista Brasileira de Zootecnia 30, no. 5 (October 2001): 1630–38. http://dx.doi.org/10.1590/s1516-35982001000600033.
Pina, Douglas dos Santos, Sebastião de Campos Valadares Filho, Rilene Ferreira Diniz Valadares, José Maurício de Souza Campos, Edenio Detmann, Marcos Inácio Marcondes, André Soares de Oliveira, and Rafael Monteiro Araújo Teixeira. "Consumo e digestibilidade aparente total dos nutrientes, produção e composição do leite de vacas alimentadas com dietas contendo diferentes fontes de proteína." Revista Brasileira de Zootecnia 35, no. 4 (August 2006): 1543–51. http://dx.doi.org/10.1590/s1516-35982006000500037.
Najas, Myrian Spinola, Rosemarie Andreazza, Ana Lucia Medeiros de Souza, Anita Sachs, Ana Cristina B. Guedes, Lilian Ramos Sampaio, Luiz Roberto Ramos, and Eliete Salomon Tudisco. "Padrão alimentar de idosos de diferentes estratos socioeconômicos residentes em localidade urbana da região sudeste, Brasil." Revista de Saúde Pública 28, no. 3 (June 1994): 187–91. http://dx.doi.org/10.1590/s0034-89101994000300004.
Figueiredo, Darcilene Maria de, Mário Fonseca Paulino, Edenio Detmann, Eduardo Henrique Bevitori Kling de Moraes, Sebastião de Campos Valadares Filho, and Marcos Gonçalves de Souza. "Fontes de proteína em suplementos múltiplos para bovinos em pastejo no período das águas." Revista Brasileira de Zootecnia 37, no. 12 (December 2008): 2222–32. http://dx.doi.org/10.1590/s1516-35982008001200021.
Macitelli, Fernanda, Telma Teresinha Berchielli, Juciléia Aparecida da Silva Morais, Roselene Nunes da Silveira, and Roberta Carrilho Canesin. "Desempenho e rendimento de carcaça de bovinos mestiços alimentados com diferentes volumosos e fontes protéicas." Revista Brasileira de Zootecnia 36, no. 6 (December 2007): 1917–26. http://dx.doi.org/10.1590/s1516-35982007000800028.
Дисертації з теми "Protéines MFS":
Yousefian, Narek. "The three-component multidrug MFS-type efflux pump EmrAB-TolC from Escherichia coli : from cloning to structural analysis." Thesis, Bordeaux, 2020. http://www.theses.fr/2020BORD0065.
Currently, due to the misuse of antibiotics, we are facing a major public health problem. The resistance to antibiotics of certain bacterial strains makes the treatment of infections very complex. In this context, the present thesis project concerns the study of a bacterial efflux complex capable of transporting antibiotics from the cytoplasm to the outside of the cell. This complex is composed of an inner-membrane Major Facilitator Superfamily (MFS) transporter (EmrB, E. coli multidrug resistance), a channel of the outer membrane TolC (Tolerance to Colicin E1) and a periplasmic adapter (EmrA, E. coli multidrug resistance). Unlike RND-type efflux systems (such as AcrAB-TolC), little is known about the MFS-type EmrAB-TolC system. It is therefore important to study the entire complex on a structural and functional level, to analyse the marked differences between these two types of transport systems. The goal of my thesis project was to study at least one EmrAB-TolC complex from a structural point of view. For my studies the aim was to isolate the complex directly from bacteria overexpressing the three protein partners. In a first step, 15 homologous EmrAB-TolC systems were identified and their corresponding genes amplified from genomic DNA of different Gram-negative bacteria. Among the genes of the 15 systems, the genes coding for the E. coli and V. cholerae systems were further studied. The expression vectors encoded fluorescent markers for the monitoring of the expression levels of different proteins and for studying the formation of complexes. In a first step, the different protein expression levels (EmrB-mRFP1 and EmrA-sfGFP) were studied for several expression strains of E. coli by measuring the red and green fluorescence levels and by Western blot (anti-His, Myc, and Strep for EmrB, EmrA, and TolC). The E. coli strain C41(DE3) was best suited for co-expression of EmrAB-TolC. In a second step, the FSEC (Fluorescence detection Size Exclusion Chromatography) methodology was used to identify a complex suitable for structural study. Thus this method enabled the observation that the EmrAB-TolC complex of E. coli was produced in higher amount than that of V. cholerae. The final co-purification protocol consists in perfoming a gentle lysis of the bacteria using lysozyme, then after solubilization with DDM, the purification is started by a Ni2+-NTA affinity chromatography step followed by a size exclusion chromatography step. Finally, the fractions containing the three protein partners are used for the detergent-exchange by amphipol A8-35 before the structural study by electron microscopy. Negative stain EM-micrographs displayed elongated objects with a length of 33 nm in side view. An average image of EmrAB-TolC shows similarities to that of the AcrAB-TolC complex observed under similar conditions. Similarities included the characteristic densities of TolC. Whereas differences were found in the lower part of EmrAB which is thinner than the lower part of AcrAB. The densities visible above the amphipol-ring correspond to EmrA, which displays a channel-like structure as in AcrA. The channel however seems to extend further towards the amphipol belt. Since EmrB does not have an extended periplasmic domain as the RND proteins have, these densities are therefore solely assigned to EmrA. EmrA, on the other side, contacts TolC akin to the interaction of AcrA/MexA to their cognate outer membrane channels (TolC/OprM) in a ‘tip-to-tip’ fashion
Aufgrund des Missbrauchs von Antibiotika stehen wir derzeit vor einem großen Problem deröffentlichen Gesundheit. Die Antibiotikaresistenz bestimmter Bakterienstämme macht die Behandlungvon Infektionen sehr komplex.In diesem Zusammenhang befasst sich diese Arbeit mit der Untersuchung eines bakteriellenEffluxkomplexes, der Antibiotika vom Zytoplasma zur Außenseite der Zelle transportieren kann. DieserKomplex besteht aus einem Major Facilitator Superfamily (MFS) Transporter der inneren Membran(EmrB, E. coli multidrug resistance), einem Kanal der äußeren Membran TolC (Tolerance to Colicin E1)und einem periplasmatischen Adapter (EmrA, E. coli multidrug resistance).Im Gegensatz zu Effluxsystemen vom RND-Typ (wie AcrAB-TolC) ist über das EmrAB-TolCSystemvom MFS-Typ wenig bekannt. Es ist daher wichtig, den gesamten Komplex auf struktureller undfunktioneller Sicht zu untersuchen, um die deutlichen Unterschiede zwischen diesen beiden Arten vonEffluxsystemen zu analysieren.Ziel meiner Doktorarbeit war es, mindestens einen EmrAB-TolC-Komplex aus struktureller Sichtzu untersuchen. Ziel meiner Studien war es, den Komplex direkt aus Bakterien, die die dreiProteinpartner überexprimieren, zu isolieren. In einem ersten Schritt wurden 15 homologe EmrAB-TolCSystemeidentifiziert und ihre entsprechenden Gene aus der genomischen DNA verschiedenergramnegativer Bakterien amplifiziert. Unter den Genen der 15 Systeme wurden die Gene, die für die E.coli und V. cholerae Systeme kodieren, weiter untersucht. Die Expressionsvektoren codiertenfluoreszierende Marker zur Untersuchung der Expression verschiedener Proteine und zur Untersuchungder Komplexbildung. In einem ersten Schritt wurden die verschiedenen Niveaus der Proteinexpression(EmrB-mRFP1 und EmrA-sfGFP) für mehrere E. coli Expressionsstämme untersucht durch Messen derroten und grünen Fluoreszenzniveaus und durch Western Blot (Anti-His, Myc und Strep für EmrB, EmrAund TolC). Der Stamm von E. coli C41(DE3) war am besten für die Koexpression von EmrAB-TolC14 geeignet. In einem zweiten Schritt wurde die FSEC-Methode (Fluorescence Detection Size ExclusionChromatography) verwendet, um einen für Strukturuntersuchungen geeigneten Komplex zuidentifizieren. Somit konnte mit dieser Methode festgestellt werden, dass der EmrAB-TolC-Komplex vonE. coli in größerer Menge als der von V. cholerae produziert wurde.Das endgültige Ko-Reinigungsprotokoll besteht darin, eine sanfte Lyse der Bakterien unterVerwendung von Lysozym durchzuführen. Nach der Solubilisierung mit DDM wird die Reinigung durcheinen Ni2+-NTA Affinitätschromatographieschritt gefolgt von einemGrößenausschlusschromatographieschritt gestartet. Schließlich werden die Fraktionen, die die dreiProteinpartner enthalten, für den Detergensaustausch durch Amphipol A8-35 vor derStrukturuntersuchung durch Elektronenmikroskopie verwendet.EM-Aufnahmen mit negativer Kontrastierung zeigten längliche Objekte mit einer Länge von 33nm in Seitenansicht. Ein durch Mittlung der Partikel erhaltenes Bild von EmrAB-TolC zeigt Ähnlichkeitenmit dem des AcrAB-TolC-Komplexes, der unter ähnlichen Bedingungen beobachtet wurde.Ähnlichkeiten schlossen die charakteristischen Dichten von TolC ein. Während im unteren Teil vonEmrAB Unterschiede festgestellt wurden, der dünner ist als der untere Teil von AcrAB. Die über demAmphipolring sichtbaren Dichten entsprechen EmrA, das wie bei AcrA eine kanalartige Strukturaufweist. Der Kanal scheint sich jedoch weiter in Richtung des Amphipolgürtels zu erstrecken. Da EmrBkeine erweiterte periplasmatische Domäne aufweist wie die RND-Proteine, werden diese Dichten daherausschließlich EmrA zugeordnet. Auf der anderen Seite kontaktiert EmrA TolC, ähnlich der Interaktionvon AcrA/MexA mit ihren jeweiligen Außenmembrankanälen (TolC/OprM), von “tip-to-tip”
Debbiche, Rim. "Influence des lipides sur la dynamique du transport du fer médié par la ferroportine-1 et sa modulation par des composés amphiphiles." Electronic Thesis or Diss., Brest, 2024. http://www.theses.fr/2024BRES0006.
Ferroportin-1(FPN1), the only known mammalian iron exporter, is expressed on the surface of various specialized cells involved in iron metabolism. This protein belongs to the Major Facilitator Superfamily (MFS) and releases intracellular iron through conformational changes oscillating between an open structure towards the cytoplasm (Inward-Facing) and an open structure towards the bloodstream (Outward-Facing; OF). It has been reported that FPN1 is preferentially localized in lipid-rafts, microdomains of the plasma membrane particularly enriched in cholesterol (CHOL). Early in the thesis, we hypothesized that direct interactions between FPN1 and surrounding lipids, notably CHOL, are necessary to stabilize FPN1 in the OF conformation and/or promote certain conformational changes. I confirmed the preferential colocalization of FPN1 in the lipid rafts of human embryonic kidney cells. The dependence of FPN1's iron export function on CHOL was examined by depletion/repletion (CHOL/epicholesterol). Mutational screening experiments supported by structural analyses of the experimental 3D structure of FPN1 in an OF state have identified three possible CHOL-binding sites (of the CARC/CRAC type). Based on molecular dynamics simulations in a simplified POPC-type lipid environment, we identify certain interactions between charged residues of the human FPN1 3D structure and the polar heads of the surrounding phospholipids, which could facilitate conformational changes of the transporter. Besides, I show, for the first time, that FPN1 function is modulated by synthetic amphiphilic compounds, ohmline and its derivatives. Through the development of a novel in vitro approach (PLA: Proximity Ligation Assay), I show that ohmline delocalizes FPN1 from lipid-rafts, thereby decreasing its interaction with its functional partner, ceruloplasmin (CP), a ferroxidase that catalyzes the oxidation of ferrous iron, and consequently its iron export function
Marchetti, Alessandro. "Développements méthodologiques pour la cristallisation et l'analyse structurale de protéines par Résonance Magnétique Nucléaire en phase solide." Thesis, Lyon, École normale supérieure, 2012. http://www.theses.fr/2012ENSL0729.
Despite the rapid diffusion of solid-state NMR (ssNMR) in the area of biomolecules, its application is far away of being systemic, and many problems remain however tobe solved before it is applied to the study of challenging solid protein assemblies. In order to extend the capabilities of ssNMR to larger substrates, the objectives of this thesis are twofold: a) to establish a new, large and more complex model system, and b) to develop new, sophisticated NMR experiments in order to improve the sensitivity and the resolution of the currently existing schemes for resonance assignment. The N-terminal domain of the Polymerase subunit III of E. coli was chosen as a target system. Sample preparation conditions are obtained, notably in combination with automated screening processes, and almost complete resonance assignment is performed based on high-power rf irradiations and slow magic-angle spinning (MAS. We show that the use use of MAS at so-called ultra-fast spinning rates (60 kHz makes possible the use of "totally low power" experiments. This yields an extraordinary increase in resolution and sensitivity, enabling the acquisition of selective cross polarization (CP) transfers, through-bond correlations and 1H-detected correlations. Narrow 1H NMR line widths and robust backbone assignment can be obtained for fully protonated medium-size protein samples in the solid state under ultra-fast magic-angle spinning, without any need for dilution against a deuterated background. The final part of this thesis concerns the study of thermotropic liquid crystals (LX) phases of a de Vries smectogen, the (S)-hexyl-lactate derivative abbreviated as 9HL, selectively deuterated
Nonostante la rapida diffusione della RMN allo stato solido (ssNMR) nell’ambito delle biomolecule, molti problemi rimangono da risolvere prima che quest’ultima possa essere applicata ad applicazioni più complesse. Allo scopo di estendere le sue potenzialità, gli obiettivi di questa tesi sono duplici. a) stabilire un nuovo sistema modello, più complesso delle semplici proteine globulari e b) sviluppare nuovi e piu sofisticati esperimenti NMR al fine di migliorare la sensibilità e la risoluzione dei metodi attualmente esistenti per l'assegnazione delle risonanze. Il dominio N-terminale dell’unita ε della DNA Polimerasi III di E.Coli è stato scelto come sistema bersaglio. Le condizioni di preparazione del campione sono ottenute grazie a processi di screening ad alta capacita, e l’assegnazione quasi complete delle risonanze è effettuata tramite l’applicazione di esperimenti routinari basati su irradiazioni RF a alta potenza e rotazioni all’angolo magico a bassa frequenza. Mostriamo che l’utilizzo di rotazioni all’angolo magico “ultra-MAS” (60 kHz) rende possibile l’uso di esperimenti “a basse potenze” mostrando uno straordinario aumento di risoluzione e sensibilità, e permettendo l’acquisizione di trasferimenti di polarizzazione selettivi, di correlazioni scalari attraverso i legami chimici e di correlazioni acquisite al protone. Larghezze di linea sottili al protone sono ottenute per campioni di proteine interamente protonate allo stato solido senza che sia necessaria diluizione in ambiente deuterato. L’ultima parte della tesi riguarda lo studio di fasi liquido-cristalline termotropiche di uno smettogeno de Vries, il derivato dello (S)-esil-lattato, abbreviato come 9HL, selettivamente deuterato
Viéville, Justine. "Etudes d'interactions moléculaires par RMN dans les systèmes complexes : utilisation de la technologie HR-MAS pour l'étude de l'interaction protéine ligand." Thesis, Strasbourg, 2014. http://www.theses.fr/2014STRAJ015/document.
NMR is a powerfull technique we decided to extend to follow interactions in complex mixtures. First part is about polydispersity index of polymer which is an important physical parameter when working with polymers. We developed here a new method, based on PEO analysis, using diffusion experiments (DOSY) by NMR to assess the polydispersity index: J. Viéville et al. / Journal of Magnetic Resonance 212 (2011) 169–173. In a second time, we worked on peptidic nucleic acids, PNA. These chemicals molecules are designed to bind DNA or RNA for clinical studies. We studied PNA in solution, by NMR to showwhich kind of interactions they form on themselves. We found very stable complexes with high fusion temperatures. Circular dichroism measurements were helpful for fusion temperature determination and structural studies. To complete this panel, we were interested in the study of protein-ligand interaction. We developed a new way to follow them, using a grafted protein on a solid phase based on HR-MAS NMR technology: J.M.P. Viéville et al. / Journal of Pharmaceutical and Biomedical Analysis 89 (2014) 18–23
Renault, Marie. "Etudes structurales et dynamiques de la protéine membranaire kpOMPA par RMN en phase liquide et solide." Toulouse 3, 2008. http://thesesups.ups-tlse.fr/254/.
The structure determination of integral membrane protein is one of the most challenging applications of current structural biology. They constitute about one third of all proteins in living organisms and are core components of many essential cellular processes. Only 0. 7% entries in the Protein Data Bank represent three-dimensional structures of membrane proteins. Our understanding about their dynamics is even more rudimentary, while the nature of biological membranes suggests that it is both complex and critical to their functions. In this regard, important advances in NMR spectroscopy have been made in the past ten years that have extended the range of molecules that are amenable to investigation, notably membrane proteins. We report herein the three dimensional structure of the transmembrane domain of OmpA from klebsiella pneumoniae (KpOmpA) in detergent micelles (60-70 kDa) by solution state NMR. For such purpose, the so-called Transverse Relaxation-Optimized SpectroscopY approaches at high magnetic field, combined to cryogenic technology and refined isotope labelling strategies has been used. The KpOmpA dynamics was assessed in a residue specific manner at various timescales by [15N, 1H]-NOEs (ps-ns), exchange broadening (ms) and 1H-2H chemical exchange (hours-weeks). .
Thebault, Sabine. "Caractérisation d'une nouvelle protéine humaine contenant un domaine homologue à l'I-mfa : implication dans la régulation de l'expression de deux rétrovirus humains, HTLV-I et HIV-1." Montpellier 1, 2000. http://www.theses.fr/2000MON1T013.
Bielska, Olga. "The role of PKD in mitochondrial fission during mitosis." Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAJ009.
Over the last two decades, multiple studies have uncovered and strengthen the implication of mitochondrial dynamics in cancer. During my thesis, I discovered an unanticipated role for the PKD kinase family in mitochondrial fission. Loss of PKD activity led to blockade of mitochondrial fission and resulted in a significant elongation of mitochondria by unopposed fusion. Mechanistically, we showed that PKDs regulated mitochondrial dynamics by activating the mitochondrial fission factor (MFF) through phosphorylation of multiple sites. MFF acts as a main receptor for the large GTPase DRP1, which constricts mitochondria, and it is critical for proper mitochondrial division. All three PKD family members could phosphorylate MFF. PKD-mediated MFF phosphorylation and mitochondrial fragmentation occurred specifically during mitosis. As MFF phosphorylation was found to be significantly upregulated in highly mitotic cancers, which was evidenced in several global phosphoproteome studies, the discovered PKD-MFF signaling axis regulating mitochondrial dynamics in mitosis could become an attractive therapeutic avenue for cancer treatment
Warnet, Xavier. "Études des membranes biologiques par RMN du solide in cellulo." Sorbonne Paris Cité, 2015. http://www.theses.fr/2015USPCC177.
Nuclear Magnetic Resonance (NMR) spectroscopy has revealed efficient for in situ (and in vivo) structural studies of biological macro-molecules. The first studies focused on small soluble molecules, and quickly, the interest shifted toward the study of soluble proteins. For few years now, magie-angle spinning (MAS) solid-state NMR has appeared as a technique of choice to obtain structural information about membrane proteins in their native environment (biological membranes). It is now well established that the two major components of biological membranes, that is to say: lipids and membrane proteins, are intimately connected, and the study of their mutual influences constitute a crucial step in die comprehension of biological membranes as a whole. In order to bring some dues regarding this question we have chosen a particular system: the strain C43(70E3) and its network of proliferating membranes, formed after the over-expression of the b subunit of the ATP synthase F1F0 of E. Coli. The analysis of the organisation of this network, and the involvement of the b subunit (via MAS NMR 13C/15N) and lipids (via mass spectrometry and MAS NMR 31P) allowed us to obtain some information regarding the importance of these two components in the establishment and stabilisation of this membrane network. Moreover, during this project, the combination of 2H NMR and MAS appeared as a technique particularly suited for die study of biological membranes of whole cells (alive) under various growth conditions. Also, the methods used and developed during this project could prove beneficial in the study of various biological membranes, from a proteic and lipidic stand point
Bertarello, Andrea. "Magic-angle Spinning NMR of paramagnetic metalloproteins." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEN004/document.
Most of our understanding of metalloproteins derives from atomic or molecular structures obtained from diffraction methods on single crystal samples. However, not all proteins are amenable for diffraction studies, and even when a highly-resolved structure is available, often the nature of the metal ion, its coordination geometry or its oxidation state are not determined. The aim of the present thesis is the investigation of structural properties of metal sites in paramagnetic metalloproteins by Magic-Angle Spinning Nuclear Magnetic Resonance (MAS NMR). MAS NMR is a powerful technique for the investigation of biological systems, and may represent a direct probe of the structure at the active site of paramagnetic metalloproteins. However, it suffers from limited sensitivity and resolution when applied to nuclei close to a paramagnetic center.In this thesis, we address these limitations by developing NMR methods based on ultra-fast (60-111 kHz) MAS rates. A “toolkit” of suitably designed pulse sequences is built for the detection and the assignment of nuclei in close proximity of a paramagnetic center. State-of-the-art computational techniques are also employed to convert the experimental data into structural restraints for obtaining atomic-resolution geometries of active sites. We benchmark this approach with the study of Fe, Cu and Co sites in two microcrystalline proteins, and we also provide preliminary data on a non-diffracting divalent metal ion transporter in lipid membranes. We anticipate that the techniques described here are an essential tool to elucidate many currently unanswered questions about structure and function of metal sites in structural biology
Pavoni, Serena. "Mise au point d’un nouveau modèle d’organoïde cérébral humain pour l’étude des mécanismes d’interaction de la protéine prion et de l’amyloïde β". Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS427.
Prion-like mechanisms are known to underlie most of human neurodegenerative diseases including Alzheimer’s disease (AD), which is characterized by two important pathological markers, β amyloid (or Aβ at the origin of the etiopathogenic amyloid cascade hypothesis) and phosphorylated tau protein. Furthermore, the prion protein (PrPC) interacts at multiple levels with the metabolism of Aβ, by mechanisms which are not well understood. To overcome the current limits in the development of efficient strategies to treat AD, the pharmaceutical industry requires innovative experimental models. However, even if a lot of progress has been achieved by using transgenic mouse models, to date no in vivo model can reflect the complexity of human brain or reproduce a clinical context. 2D in vitro cell culture models are unable to allow the aggregation and accumulation of pathological proteins as observed in vivo. The aim of this study consists in taking advantage of the research prospects offered by induced pluripotent stem cell (iPSCs) in the field of neurosciences. iPSCs can be used to generate 3D models of differentiation also called human cerebral organoids or mini-brains (MBs). Their ability to self-organise in 3D neuroectodermic tissue leds to a complex system that mimics different human cerebral structures in which we were able to characterize the expected markers. The study of the two proteins of interest (APP and PrPC) during neural differentiation has allowed us to follow the modulation of protein expression level occurring during the in vitro development of the human MBs. In order to use this model to reproduce the protein accumulation mechanisms seen in AD, we have tested chemical inductors such as Aftin-5 in order to modulate the APP post-transcriptional pathway towards a pathological outcome. Many strategies of treatment are adopted to lead APP cleavage and Aβ generation. The production of soluble fragments Aβ38, Aβ40, Aβ42 in the supernatant of organoids has been showed using ELISA technique. The levels generated are reproducible and the increase of Aβ42/Aβ40 ratio is consistent with extrapolated data from mouse and human models thus validating our model. Analysis at the gene and protein level has been assessed in order to understand the interaction between PrPC and APP after treatment. The long-term goal consists in improving this model which is notably hampered by the absence of vascularization and the low level of maturation of the neural tissue. The main challenge in MB culture thus consists in the integration of the vascular system, and also in increasing the speed of ageing process in vitro for the study of neurodegenerative diseases. In the long term, the prospect of automating the culture of MBs would allow the use of the system for cytotoxicity testing and/or high throughput screening for the discovery of new drugs for AD
Книги з теми "Protéines MFS":
L, Burlingame A., ed. Biological mass spectrometry. Amsterdam: Elsevier Academic Press, 2005.
Burlingame, A. L. Biological Mass Spectrometry. Elsevier Science & Technology Books, 2005.