EUCUREOA · SirT1 Regulation of Aggrecan Expression in Human Chondrocytes
7РП — „Хора“ (Действия „Мария Кюри“)
- Период
- 2010-09-01 → 2014-08-31
- Финансиране от ЕС
- 100 000 €
- Участници
- 1
- Схема
- MC-IRG
Линиите свързват координатора с партньорите.
Накратко на български
Протеинът Sirt1 регулира производството на агрекан и колаген в хрущялни клетки, като при остеоартрит нивата му спадат. Разбирането на този механизъм помага да се разбере как възпаленията разрушават ставите и как се влияе върху жизнеспособността на клетките.
Кратко обяснение, генерирано от езиков модел по текста на CORDIS. Оригиналът е по-долу.
Резултати накратко
SirT1 Regulation of Aggrecan Expression in Human Chondrocytes
Osteoarthritis (OA) is a degenerative joint disease of the articular cartilage (AC) characterized by accelerated extracellular matrix (ECM) degradation and severe pain-dysfunction. In a previous study, the NAD-dependent protein deacetylase, Sirt1, was shown to positively regulate cartilage-type ECM gene expression, namely aggrecan and collagen 2a1. Histological and biochemical evaluations of OA cartilage exhibit reduced Sirt1 protein levels as compared to normal cartilage samples. For collagen 2a1, Sirt1 forms complexes with several transcription factors (TF) and coactivators on the promoter sites of these genes, inducing their transcription and expression. Since both aggrecan and collagen 2a1 are co-expressed in healthy cartilage, it is hypothesized that both genes are regulated by Sirt1. We hence envision that reduced Sirt1 activity and protein levels are mechanistically linked with the impaired capacity of chondrocytes to express these genes, thereby perpetuating the pathogenesis of OA. Numerous reports show that enhanced exposure to inflammatory cytokines is an integral part of OA progression. To this end, my group has additionally investigated the effect inflammatory mediators on Sirt1, and the attributes of such alterations in cartilage biology and homeostasis. Our observations established that the lysosomal cathepsin B cleaves Sirt1 in human chondrocytes treated with TNFalpha and/or IL1beta. We additionally show that this cleaved fragment (75kDa Sirt1; 75Sirt1) could prolong chondrocyte viability under pro-inflammtory conditions. These data were further validated in-vivo using a comparison between Sirt1 w.t. and haploinsufficient mice at young (1 month) and in older ages (9 months). Expectedly, research obtained regarding Sirt1 in cartilage biology, will impact the generation of novel disease-modifying drugs to modulate Sirt1 activity and prevent age-related cartilage degeneration, as seen in OA.
Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз
Цел на проекта
Osteoarthritis (OA) is a degenerative joint disease of the articular cartilage (AC) characterized by accelerated extracellular matrix (ECM) degradation and severe pain- dysfunction.The chromatin modifying enzyme, SirT1 has been shown to affect cartilage-type ECM gene expression. More specifically, SirT1 forms complexes with Sp1/Sox9 transcription factors (TFs), and induces collagen IIa1 (Coll-II) transcription. Similar to Coll-II, aggrecan has also been established to positively correlate with SirT1 expression. In AC, Coll-II and aggrecan are co-expressed and both genes present Sp1 and Sox9 binding sequences. I therefore hypothesize that Sp1 and/or Sox9 are involved in SirT1-aggrecan proximal promoter- Exon1 (APP/Ex1) association and aggrecan expression.Accordingly, my specific aims are to (1) characterize Sox9 and Sp1 binding to human APP via chromatin-immunoprecipitation (ChIP) analysis and Luciferase assays; (2) establish SirT1 association with Sp1/Sox9 and SirT1-Sp1/Sox9 complex localization on APP/Ex1 using reverse immunoprecipitation (revIP) and Sequential ChIP (SeqChIP), respectively; (3) test if SirT1- Sp1/Sox9 complex is essential for APP/Ex1-driven gene expression. This will be achieved by co-transfecting a luciferase-tagged-APP/Ex1 with SirT1 and Sp1/Sox9, followed by quantitative luminescence; (4) elucidate the presence of known SirT1-associated CMEs (i.e. GCN5 and SET7/9) and their respective histone hallmarks AcH4K5 and 3MeH3K4. This aim will be achieved by means of ChIP analyses of the actively transcribed APP/Ex1.Despite the high incidence of OA in developed countries, there is no treatment for this debilitating disease. Expectdly, the proposed study in humans will provide a regulatory mechanism for aggrecan production, thus identifying novel targets for the treatment of OA and the early diagnosis of susceptible individuals. This last notion is highly relevant, as susceptible subjects may be advised to prevent overloading of their joints.
Оригинален текст от CORDIS (на английски).
Участници
- THE HEBREW UNIVERSITY OF JERUSALEM · JerusalemКоординаторИзраел
Връзки
Данни: CORDIS, © Европейски съюз