Chronic hyperlipidemia (lipotoxicity) and hyperglycemia (glucotoxicity) have recently been shown to induce Endoplasmic Reticulum (ER) stress, which may contribute to pancreatic beta-cell dysfunction in type 2 diabetes. This thesis examined the involvement of ER stress in beta-cell lipotoxicity and glucotoxicity. Although chronic treatment with saturated free fatty acids (FFA) in vitro induced ER stress, altering ER stress by increasing or knocking-down GRP78 chaperone expression had no effect on apoptosis induction. Conversely, overexpression of ER chaperones rescued the reduction in proinsulin protein levels caused by chronic exposure to high glucose, although it had no effect on the decreased insulin mRNA levels and proinsulin translation rate. Thus, ER stress is likely not the main mechanism involved in saturated FFA-induced beta-cell apoptosis in vitro, but it may contribute to glucotoxic effects on proinsulin levels. These findings have increased our understanding of the link between ER stress and beta-cell dysfunction in type 2 diabetes.

No description available.

No description available.

New strategies are needed to counter the growing problem of bacterial resistance to antibiotics. One such strategy is to design compounds that target bacterial virulence, which could work separately or in concert with conventional bacteriostatic or bactericidal antibiotics. Pilicides are a class of compounds based on a ring-fused 2-pyridone scaffold that target bacterial virulence by blocking the chaperone/usher pathway in E. coli and thereby inhibit the assembly of pili. This thesis describes the design, synthesis, and biological evaluation of compounds based on the pilicide scaffold with the goal of improving the pilicides and expanding their utility. Synthetic pathways have been developed to enable the introduction of substituents at the C-2 position of the pilicide scaffold. Biological evaluation of these compounds demonstrated that some C-2 substituents give rise to significant increases in potency. X-ray crystallography was used to elucidate the structural basis of this improved biological activity. Furthermore, improved methods for the preparation of oxygen-analogues and C-7 substituted derivatives of the pilicide scaffold have been developed. These new methods were used in combination with existing strategies to decorate the pilicide scaffold as part of a multivariate design approach to improve the pilicides and generate structure activity relationships (SARs). Fluorescent pilicides were prepared using a strategy where selected substituents were replaced with fluorophores having similar physicochemical properties as the original substituents. Many of the synthesized fluorescent compounds displayed potent pilicide activities and can thus be used to study the complex interactions between pilicide and bacteria. For example, when E. coli was treated with fluorescent pilicides, it was found that the compounds were not uniformly distributed throughout the bacterial population, suggesting that the compounds are primarily associated to bacteria with specific properties. Finally, by studying compounds designed to inhibit the aggregation of Aβ, it was found that some compounds based on the pilicide scaffold inhibit the formation of the functional bacterial amyloid fibers known as curli; these compounds are referred to as 'curlicides'. Some of the curlicides also prevent the formation of pili and thus exhibit dual pilicide-curlicide activity. The potential utility of such 'dual-action' compounds was highlighted by a study of one of the more potent dual pilicide-curlicides in a murine UTI model were the compound was found to significantly attenuate virulence in vivo.

Els organismes responen a la temperatura i a molts altres estressos sintetitzant un grup de proteïnes anomenat proteïnes de xoc de calor (HSPs). En plantes les sHsps, d'entre 15 i 30 kDa formen el grup més abundant i divers, classificat en funció de la seva localització subcel.lular i homologia en: mitocondrials, cloroplàstiques, de reticle endoplasmàtic i citoplàsmiques de classe I i II. Les sHsps-CI s'ha descrit que s'indueixen per estrès tèrmic, hídric i oxidatiu (peròxid d'hidrògen, llum UV, ozó) i en resposta a algunes hormones. També s'expressen durant el desenvolupament, per exemple durant l'embriogènesi, on es creu que podrien tenir un paper protector de l'embrió enfront la dessecació. Tot i que hi ha abundants treballs que correlacionen la resistència a l'estrès i l'acumulació de sHsps-CI, els mecanismes moleculars d'aquesta activitat són poc conguts. Tot i això, per diverses sHsps-CI ha estat descrita una activitat xaperona in vitro i, més recentment, que la seva sobreexpressió augmenta la viabilitat de cèl.lules d'E.coli en condicions d'estrès tèrmic.L'estudi de l'acumulació de sHsps-CI en surera (Quercus suber) mitjançant immunodetecció en electroforesi bidimensional mostra uns patrons d'acumulació complexos i formats per dos grups d'espècies proteiques principals, a l'entorn dels 10 i 17 kDa respectivament, que mostren una inducció diferencial en funció del teixit i l'estrès. Mentre que les espècies proteiques de 17 kDa s'indueixen per temperatura però no per estrès oxidatiu, les de ca. 10 kDa ho fan per estrès oxidatiu i no per temperatura. Ambdós grups d'espècies proteiques s'acumulen conjuntament en fel.lema. Assajos de PCR i RT-PCR han permès clonar parcialment tres noves sHsps-CI en surera: Qshsp10-CI, QshspC-CI i QshspD-CI. Aquest fet confirma la multigeneïcitat de les sHsps-CI en surera que apuntava el patró bidimensional. Dels nous clons obtinguts destaca especialment Qshsp10-CI, un gen que presenta un codó stop enmig del domini -cristal.lí que fa que a la proteïna que se'n dedueix li manqui un 55% del domini -cristal.lí i tota l'extensió C-terminal. Es tractaria de la sHsp més petita i més truncada descrita fins al moment. L'anàlisi de l'expressió de Qshsp10-CI mitjançant RT-PCR mostra expressió en plantes tractades amb H2O2 però no en les que han estat sotmeses a un xoc de calor. Aprofitant l'oportunitat que oferia aquesta sHsp-CI de ser utilitzada com a model per l'estudi de la importància del domini -cristal.lí i l'extensió C-terminal en l'activitat protectora enfront l'estrès, es va voler determinar la capacitat que tenia d'augmentar la viabilitat de cèl.lules d'E. coli en condicions d'estrès tèrmic i oxidatiu. Els resultats mostren que la proteïna recombinant QsHsp10-CI, tot i la important truncació que té, és capaç de protegir cèl.lules d'E. coli en condicions d'estrès tèrmic i, remarcablement, en condicions d'estrès oxidatiu. Tots aquests resultats indiquen que les espècies proteiques de ca. 10 kDa podrien correspondre a Qshsp10-CI i tenir un paper en les cèl.lules del fel.lema en la protecció enfront l'estrès oxidatiu.L'estrès oxidatiu provoca lesions al DNA que poden produir errors en la replicació, transcripció o traducció i generar proteïnes aberrants. Donades les condicions d'estrès oxidatiu a les quals es troben sotmeses les cèl.lules del fel.lema, s'ha volgut estudiar la variabilitat dels seus àcids nucleics. La determinació de la taxa de mutació de la regió codificant del gen Qshsp17.4-CI en mRNA i DNA de fel.lema i àpex radicular, un teixit jove i en creixement actiu va mostrar unes taxes sorprenentment elevades en l'mRNA (1/1784 pb) i el DNA genòmic (1/1520 pb) del fel.lema. Aquestes taxes són les més altes descrites en un genoma nuclear eucariota i són similars a les dels virus d'RNA d'evolució ràpida com el virus de l'Hepatitis C. Amb aquestes taxes de mutació, un terç dels mRNAs del fel.lema de la surera contindrien missatges aberrants i la supervivència de les cel.lules es veuria compromesa. Això implica que el fel.lema hauria de ser considerat com un mosaic de cèl.lules genèticament heterogènies i, per tant, una sola seqüència no defineix en tota la seva amplitud un gen en aquest teixit. No es va detectar cap mutació en àpex de rel. Amb l'objectiu d'aprofundir en el coneixement de les mutacions que es donen en aquests dos teixits i per tal de poder fer una anàlisi qualitativa més completa que permetés especular sobre el seu origen, es va aplicar un mètode de selecció de seqüències mutants en base a la utilització d'enzims de restricció. Les mutacions detectades en fel.lema es corresponen amb les relacionades, en altres sistemes no nuclears (plasmidis, fags i DNA bacterià), amb l'estrès oxidatiu. En conseqüència, l'estrès oxidatiu al qual estan sotmeses les cèl.lules del fel.lema podria ser el causant de l'elevada taxa de mutació detectada. D'acord amb això, el tipus majoritari de productes d'oxidació de les bases del DNA que s'acumulen en brots de plàntules de surera en resposta al peròxid d'hidrògen produeixen el mateix tipus de mutacions detectades en l'mRNA del fel.lema de la surera. La major sensibilitat d'aquest nou mètode ha permès, a més, detectar mutacions en molècules d'mRNA de rel, un teixit en el qual no s'havia trobat cap mutació utilitzant el mètode de clonatge i seqüenciació directa. Tot i això, el tipus de mutacions predominants no estan relacionades amb l'estrès oxidatiu sinó amb erros en la reparació dels àcids nucleics. / Small heat shock proteins (sHsps,15-30 kDa) are the most abundant and diversified Hsps in plants. They have been classified according to its homology and cellular localisation in: mitochondrial, chloroplastic, endoplasmic reticulum and class I and II citoplasmic sHsps. Although sHsps-CI are involved in the stress response and accumulate at some stages of embryonic development and there is abundant work correlating stress resisitance and sHsps accumulation, the molecular mechanisms of their activity are not well known. However, in vivo and in vitro chaperone activity under temperature stress has been described. 2D immunodetection patterns of cork oak (Quercus suber) sHsps-CI (thermic, hydric and oxidative). At the 17 kDa region there is a set of protein species highly induced by temperature and, at least some of them correspond to QsHsp17.4-CI. On the other hand, protein species at the ca. 10 kDa region are highly induced under oxidative stress conditions and accumulate in the endogenous oxidatively stressed tissues xylem and phellem but not after a heat shock. PCR and RT-PCR assays allowed us to clone three new members of the sHsps-CI multigenic family in cork oak. Among them, Qshsp10-CI is specially interesting because codes for a truncated protein that lacks 55% of the -crystallin domain and all the C-terminal extension, being the more C-terminal truncated sHsp reported to date. Overexpression of recombinant QsHsp10-CI and a more truncated protein lacking the whole -crystallin domain in E. coli cells shows that most of the -crystallin domain and all the C-terminal extension are dispensable, but amino acids 1 to 41 of the -crystallin domain (including the consensus II region) are essential for sHsps-CI protective activity under temperature and oxidative stress conditions. The expression of Qshsp10-CI in response to oxidative but not temperature stress and its protective activity of E. coli cells under oxidative stress conditions points to a correspondence between Qshsp10-CI and the ca. 10 kDa protein species detected in 2D immunodetections and a protective activity of those in the oxidatively stressed phellem cells. Endogenous oxidative stress of phellem cells might generate mutations accumulation in nucleic acids. Variability analyses of DNA and mRNA of phellem cells in the coding region of Qshsp17.4-CI showed a surprisingly high rate of mutation in both mRNA (1/1784 bp) and genomic DNA (1/1520 bp). These are the highest rates described for a nuclear eukariotic genome and are similar to those detected in RNA viruses. With these mutation rates one third of mRNAs of phellem cells would contain mutations and code for abnormal proteins. No mutations were detected in root tip, a normally growing young tissue. With the aim of deeping into the nature of mutations that accumulate in phellem cells, we applied a method to in vitro select mutant sequences using restriction enzymes. The types of mutation predominant in phellem cells mRNA were those related with oxidative stress in other systems (plasmids, phages and bacterial DNA). In addition, the predominant DNA lesions that accumulate in H2O2 treated cork oak plantlets, as shown by GC-MS analyses, generate the same type of mutations detected in mRNA of phellem cells. Accordingly, the high accumulation of mutations detected in phellem cells might be due to its endogenous oxidative stress. Moreover, young and actively growing tissues are also subjected to a certain degree of base lesions and mRNA mutations. However, both mutational spectrum and accumulation levels are different compared to oxidatively stressed tissues.

Le VIH-1 bourgeonne sous forme immature et doit subir l’étape de maturation afin d’acquérir son caractère infectieux. La maturation protéolytique du précurseur Pr55Gag induit le réarrangement morphologique de la particule alors que le dimère d’ARNg acquiert une compaction optimale. Ces réarrangements conformationnels restent encore inconnus et sont facilités par l’activité chaperonne de la protéine NCp7. Notre but a été de déterminer les différentes étapes menant à l’obtention d’un dimère d’ARNg mature. Nous avons donc étudié la structure des 550 premiers nucléotides du génome par cartographie chimique, à la fois 1. in vitro en présence des protéines Pr55Gag, GagΔp6, intermédiaires contenant le domaine NC et NCp7 et 2. in viro par l’approche hSHAPE-Seq que nous avons développé. Les particules matures et bloquées aux différentes étapes de maturation de Pr55Gag ont été analysées ainsi que des particules matures et totalement immatures traitées avec l’éjecteur de zinc AT-2. Ce traitement permet d’identifier les sites de protection de Pr55Gag et NCp7 ainsi que leur activité déstabilisatrice. / The HIV-1 particle buds from the infected cell as an immature particle and has to undergo a maturation process to become infectious. Proteolytic processing of Pr55Gag triggers morphological rearrangements of the particle whereas the gRNA dimer becomes more stable. Genomic rearrangements remain poorly understood and are facilitated by the RNA chaperone activity of the NCp7 protein. Our goal was to determining the different steps leading to the formation of the mature dimeric gRNA. To this end, the structure of the first 550 nucleotides of the HIV-1 genome was assessed by chemical probing 1. in vitro with Pr55Gag, GagΔp6, NC-containing intermediates and NCp7 proteins and 2. in viro with the hSHAPE-Seq approach we developed. Wild type and mutant viruses mimicking the sequential processing of Pr55Gag were analysed, as well as immature PR- and mature particles treated with the AT-2 zinc ejector, in order to identify the Pr55Gag and NCp7 binding sites and their gRNA destabilising activity.

Abstract The delta opioid receptor (δOR) is a member of the G protein-coupled receptor family. This transmembrane receptor has an important role in the regulation of pain. The OPRD1 gene that encodes the human δOR (hδOR) contains at least 11 single-nucleotide polymorphisms (SNPs). The only nonsynonymous SNP resides in the amino-terminal (N-terminal) domain of the receptor and it replaces Phe at position 27 with Cys, thus introducing an unpaired Cys residue on the extracellular surface of the receptor. The Cys27 variant has been shown to have an allelic frequency of about 10% in Caucasian populations. The polymorphic site is flanked by two putative N-glycosylation sites at Asn18 and Asn33. In this study, the folding, maturation and trafficking of hδOR was assessed using the hδORPhe27 and hδORCys27 variants and the N-glycosylation deficient forms of the latter as models in a heterologous expression system. The effects of N-glycosylation and the unpaired Cys-residue were studied with various biochemical, pharmacological and cell biological methods. In addition, protein-protein interactions of the intracellular hδOR precursors were assessed. The hδORCys27 and hδORPhe27 variants differed significantly in their subcellular localization and maturation efficiency. The newly synthesized hδORCys27 was found to accumulate in the endoplasmic reticulum (ER) prior to its ER-associated degradation in proteasomes. Although a slow maturation rate was characteristic for both variants, only the hδORCys27 had poor maturation efficiency. The cell surface expression of hδORCys27 was further decreased because the constitutive internalization of this receptor was enhanced compared to hδORPhe27. N-linked glycosylation was not required for hδOR function or ligand binding, but was important for the expression of the correctly folded receptor species at the cell surface. The mutant non-N-glycosylated receptor was shown to traffic to the cell surface with enhanced kinetics, but some of the plasma membrane receptors were in a nonnative conformation. Also, the overall levels of the non-N-glycosylated hδORCys27 were decreased as the receptor was efficiently internalized for lysosomal degradation in a constitutive fashion. The hδORCys27 and hδORPhe27 precursors were found to interact with several ER localized proteins, such as calnexin (CNX), protein disulfide isomerase (PDI) and ERp72. The receptors also associated with the sarco(endo)plasmic reticulum calcium ATPase 2b (SERCA2b), which was shown to occur during translocation of the receptor to the ER membrane or immediately thereafter. The interaction was not receptor N-glycan dependent and the normal functional activity of SERCA2b was shown to be required for proper cell surface expression of hδOR. / Tiivistelmä δ-opioidireseptori kuuluu G-proteiinikytkentäisiin reseptoreihin, ja sillä on tärkeä rooli kivun säätelyssä. Ihmisen δ-opioidireseptoria koodaavassa OPRD1 geenissä on havaittu ainakin 11 yhden nukleotidin polymorfiaa. Vain yksi tunnetuista polymorfioista aiheuttaa muutoksen proteiinin aminohapposekvenssiin. Se sijaitsee reseptorin aminoterminaalisessa osassa ja se muuttaa fenyylialaniinin (Phe) kohdassa 27 kysteiiniksi (Cys), joka on pariton. Cys27-variantin yleisyys eurooppalaisessa väestössä on noin 10 %. Polymorfisen kohdan molemmilla puolilla on N-glykosylaatiokohdat asparagiineissa Asn18 ja Asn33. Tämän työn tavoitteena oli tutkia δ-opioidireseptorin laskostumista, maturaatiota ja kuljetusta heterologisessa solumallissa käyttämällä Phe27- ja Cys27-variantteja sekä Cys27-variantin N-glykosyloimatonta mutanttia. Cys27-polymorfian ja N-glykosylaation vaikutuksia tutkittiin useilla biokemiallisilla, farmakologisilla sekä solubiologisilla menetelmillä. Lisäksi työssä tutkittiin solunsisäisen δ-opioidireseptorin esiasteen vuorovaikutusta muiden proteiinien kanssa. Phe27- ja Cys27-varianttien sijainti solun sisällä ja maturaatiotehokkuus eroavat toisistaan merkittävästi. Vastasyntetisoitu Cys27-variantti kerääntyy endoplasmakalvostoon, josta se ohjautuu proteasomihajoitukseen. Molemmat variantit kulkeutuvat solun pintaan hitaasti. Cys27-variantin prosessointi on huomattavasti tehottomampaa ja sen määrää solun pinnalla vähentää myös lisääntynyt ohjaaminen solunsisäiseen lysosomihajotukseen. N-glykosylaatiolla ei havaittu olevan vaikutusta reseptorin toimintaan tai ligandin sitomiseen, mutta sillä on tärkeä merkitys oikein laskostuneiden reseptorien kuljetukselle solun pinnalle, koska osa pintaan päässeistä N-glykosyloimattomista reseptoreista on muodossa, johon reseptorispesifinen ligandi ei sitoudu. Vaikka mutanttireseptori kulkeutuukin solun pintaan nopeammin, sen määrä solun pinnalla on alhaisempi, koska mutanttireseptori ohjataan huomattavan nopeasti solun pinnalta lysosomihajotukseen. Phe27- ja Cys27-varianttien havaittiin olevan myös vuorovaikutuksessa eräiden endosomaalisen kalvoston proteiinien kanssa, kuten kalneksiinin, proteiinidisulfidi-isomeraasin ja ERp72-proteiinin. Kumpikin reseptori havaittiin yhteisessä rakenteessa sarko(endo)plasmakalvoston kalsium-ATPaasi 2b -pumpun (SERCA2b) kanssa N-glykosylaatiosta riippumattomalla tavalla. Nämä proteiiniryhmät muodostuvat, kun reseptori liitetään synteesin aikana endoplasmakalvostoon tai heti sen jälkeen. Vuorovaikutus toiminnallisen SERCA2b:n kanssa havaittiin tärkeäksi toimintakykyisen δ-opioidireseptorin esiintymiselle solun pinnassa.

Du fait de sa haute conservation et de ses fonctions clés dans le virus VIH-1, la protéine de la nucléocapside NC est une cible de choix pour développer de nouveaux anti-viraux. Bien que la compréhension mécanistique des propriétés chaperonnes de NC vis-à-vis des acides nucléiques ait connu d’importants progrès, les aspects dynamiques de ces propriétés restent mal comprises, faute notamment d’outils appropriés pour les suivre au niveau moléculaire. L’objectif de ce travail de thèse a été de caractériser au niveau moléculaire la dynamique des interactions de NC avec les acides nucléiques, à l’aide d’outils fluorescents développés au laboratoire ou en collaboration. En utilisant des peptides NC et des oligonucléotides marqués en différentes positions par des analogues fluorescents d’acides aminés et de nucléosides, respectivement, nous avons pu donner une image complète du processus dynamique sous-tendant le mécanisme chaperon de NC dans le second transfert de brins de la transcription inverse du cycle du VIH-1. Cette compréhension est fondamentale pour concevoir des stratégies rationnelles afin de cibler le rôle spécifique de NC dans ses interactions avec ses cibles nucléiques. / Due to its high conservation and key functions in the HIV-1 virus, the nucleocapsid protein NC is a potential target for the development of new anti-viral drugs. Although the mechanistic understanding of the NC nucleic acid chaperone properties has achieved a significant progress, the dynamic aspects of these properties remain poorly understood, mainly due to the lack of the appropriate tools to monitor them at the molecular level. The objective of this thesis was to characterize the dynamic interactions of NC with nucleic acids at the molecular level using new fluorescent tools developed in the laboratory or in collaboration. Using NC peptides and its target oligonucleotides labeled in different positions by fluorescent amino acid and nucleoside analogs, respectively, we were able to give a complete picture of the dynamic processes underlying the chaperone activity of NC in the second strand transfer of HIV-1 reverse transcription. This understanding is fundamental to design rational strategies in order to target the specific role of NC in interaction with its nucleic acid targets.

La microscopie à force atomique (AFM) permet de visualiser la topographie d’échantillons organiqueset inorganiques à l’échelle atomique. Les innovations les plus récentes offrent désormais la possibilitéd’accéder aux propriétés nano-mécaniques des échantillons (élasticité, adhésion…). Son panel defonctionnalités permet de pallier aux besoins des nanotechnologies, tant dans les domaines de laphysique, de la chimie que de la biologie.Cependant, les besoins nécessaires à la compréhension des processus biologiques imposent aumicroscope à force atomique des vitesses d’acquisitions rapides, inférieures à la seconde par image. Leséquipements classiques n’offrent pas cette possibilité. C’est pour s’affranchir de ce verrou technologique,pour l’étude dynamique, qu’un prototype de microscope à force atomique à haute-vitesse a étédéveloppé (HS-AFM) en partenariat avec l’équipe du Professeur T. Ando à l’Université de Kanazawa(Japon). Il permet d’atteindre des vitesses de balayage identiques aux vitesses vidéos : 25-50 images/s, enmilieu liquide. Le dispositif est en perpétuelle amélioration : nouvelle boucle d’asservissement, domainesde balayage augmentés. La haute résolution est, quant à elle, assurée par des leviers miniaturisés munisde sur-pointes en carbone. Parallèlement à l’innovation du microscope en lui-même, des modulescomplémentaires ont été développés : module pousse seringue et module chauffant.Le potentiel de ce prototype, développé dans le cadre d’un programme ANR PNANO 2008 HSnanobio-Imaging, a été montré via l’étude d’une petite protéine de choc thermique : la protéine sHspLo18. Cette protéine, issue de la bactérie lactique Oenococcus oeni, offrait la possibilité d’étudier deschangements de degrés d’oligomérisation en fonction du pH, ainsi que le rôle chaperon et lipochaperonen cas de stress environnemental d’autres complexes biologiques. L’utilisation des techniques demicroscopie couplée à des études biochimiques sur ce modèle protéique a permis d’appréhender l’effetdes surfaces sur l’adsorption et la dynamique des complexes biologiques. L’interaction protéine – surfacea pu être approchée et s’avère utile au développement des capteurs à protéines / The atomic force microscopy (AFM) gives access to the topography of organic and inorganic samplesat the atomic scale. The latest innovations offer the possiblity to understand the sample nano-mechanicalproperties (elasticity, adhesion...). Its feature set allows overcoming the demands of nanotechnology,both in the fields of physics, chemistry and biology.However, understanding biological processes require faster acquisitions for the atomic forcemicroscopy, less than a second per frame. As conventional equipment does not offer the possibility toovercome the constraint of time for dynamical studies, a prototype of high-speed atomic forcemicroscope (HS-AFM) was developed in partnership with Professor T. Ando group of Kanazawa University(Japan). It can reach scanning video speed: 25-50 frames/s in a liquid medium. The device is beingconstantly improved: new feedback control, larger scanning sizes. The resolution is provided byminiaturized cantilevers with carbon EBD-tips. In parallel to innovative modules on the microscope, addonshave been developed: syringe pump and heating modules.The potential of the prototype, developed within the framework of the program ANR PNANO 2008HS-nanobio-Imaging, has been shown through the study of a small heat shock protein: the protein sHspLo18. This protein, from the lactic acid bacterium Oenococcus oeni, offered the possibility of a variouschanges of oligomerization degrees according to the pH, and also the chaperone and lipochaperon activityof protein under the influence of an environmental stress. The use of these techniques of microscopiescoupled with biochemical studies on this proteic model allowed to dread the effect of surfaces on theadsorption and the dynamics of biological complexes. The interaction protein – surface coulb be toapprehend and proves to be useful for the development of protein sensors developed in the laboratory

Many neurodegenerative diseases are characterized by the accumulation of misfolded proteins that often share common morphological and biochemical features, and can similarly co-localize with several other proteins, including various chaperone proteins. Chaperone proteins, like heat shock protein 27 (HSP27), heme oxygenase 1 (HO-1) and clusterin, have been implicated as potent modulators of misfolded proteins, thus may play important roles in the pathogenesis of neurodegenerative diseases. The present study aims to investigate their roles in the pathogenesis of Frontotemporal lobar degeneration (FTLD), Alzheimer's disease (AD), Parkinson's disease (PD), and Motor neuron disease (MND) by determining their distribution and amount via immunohistochemical staining and western blotting in diseased and control subjects.There were distinct patterns of HSP27 and clusterin immunostaining in different brain regions. For HSP27, patients with AD and FTLD were in general more severely affected than were patients with MND and control subjects. For clusterin, patients with AD and FTLD were more severely affected than control subjects where neurons and glial cells were concerned, while patients with AD and control subjects were more severely affected than those with FTLD where diffuse and cored plaques were concerned. However, there were no obvious differences in the pattern of HO-1 immunostaining in various brain regions in patients with AD or FTLD relative to control subjects. Moreover, there was no association between HSP27, HO-1 and clusterin with disease or histological type, and the ‘classic’ neuropathological changes in FTLD, AD and MND were not immunoreactive to any of these proteins. There were significant correlations between the degrees of HO-1 and clusterin immunostaining in many brain areas for both AD and FTLD cases, and for all cases overall, but none between HSP27 and clusterin or HSP27 and HO-1. Present results suggest an involvement with ongoing cellular stress, misfolded or unfolded protein accumulation or the deficits/failure of other relevant protein quality control systems, in the pathogenesis of these neurodegenerative diseases. Present work may therefore have implications for the further development of ideas concerning the cause or treatment of neurodegenerative diseases where there is aberrant accumulation of misfolded, aggregated protein, and perhaps for conformational diseases in general. However, there are still many issues remain to be elucidated. Further research aimed at understanding the function and mechanisms of the chaperone system, and other protein quality control mechanisms, in the pathogenesis of neurodegenerative diseases is still needed.