Singulièrement universel. Le problème du temps chez le dernier Sartre

Conference (2006, June 24)

Sinus elevation and simultaneous implant placement: the influence of the remaining bone height.

Poster (2007, October)

Sire procedures for dairy production traits practised in various country

(1992)

Sirt1 Controls Endothelial Angiogenic Functions During Vascular Growth

in Genes & Development (2007), 21(20),

The nicotinamide adenine dinucleotide (NAD(+))-dependent histone deacetylase Sir2 regulates life-span in various species. Mammalian homologs of Sir2 are called sirtuins (SIRT1-SIRT7). In an effort to ... [more ▼]

The nicotinamide adenine dinucleotide (NAD(+))-dependent histone deacetylase Sir2 regulates life-span in various species. Mammalian homologs of Sir2 are called sirtuins (SIRT1-SIRT7). In an effort to define the role of sirtuins in vascular homeostasis, we found that among the SIRT family, SIRT1 uniquely regulates angiogenesis signaling. We show that SIRT1 is highly expressed in the vasculature during blood vessel growth, where it controls the angiogenic activity of endothelial cells. Loss of SIRT1 function blocks sprouting angiogenesis and branching morphogenesis of endothelial cells with consequent down-regulation of genes involved in blood vessel development and vascular remodeling. Disruption of SIRT1 gene expression in zebrafish and mice results in defective blood vessel formation and blunts ischemia-induced neovascularization. Through gain- and loss-of-function approaches, we show that SIRT1 associates with and deacetylates the forkhead transcription factor Foxo1, an essential negative regulator of blood vessel development to restrain its anti-angiogenic activity. These findings uncover a novel and unexpected role for SIRT1 as a critical modulator of endothelial gene expression governing postnatal vascular growth. [less ▲]

SIRT1-deficient mice exhibit an altered cartilage phenotype and undergo increased cartilage breakdown and apoptosis

in Osteoarthritis and Cartilage (2011), 19(Suppl 1), 33

Sirtuin 1 enzymatic activity is required for cartilage homeostasis in vivo in a mouse model.

in Arthritis and Rheumatism (2013), 65(1), 159-66

OBJECTIVE: We and others previously demonstrated that sirtuin 1 (SIRT-1) regulates apoptosis and cartilage-specific gene expression in human chondrocytes and mouse models. This study was undertaken to ... [more ▼]

OBJECTIVE: We and others previously demonstrated that sirtuin 1 (SIRT-1) regulates apoptosis and cartilage-specific gene expression in human chondrocytes and mouse models. This study was undertaken to determine if SIRT-1 enzymatic activity plays a protective role in cartilage homeostasis in vivo, by investigating mice with SIRT-1 mutations to characterize their cartilage. METHODS: Articular cartilage was harvested from the paws and knees of 5- and 6-month-old wild-type (WT) mice and mice homozygous for SIRT-1(tm2.1Mcby) (SIRT-1(y/y) ), an allele carrying a point mutation that encodes a SIRT-1 protein with no enzymatic activity (y/y mice). Mice ages 2 days old and 6-7 days old were also examined. Mouse joint cartilage was processed for histologic examination or biochemical analyses of chondrocyte cultures. RESULTS: We found that articular cartilage tissue sections from y/y mice of up to 6 months of age contained reduced levels of type II collagen, aggrecan, and glycosaminoglycan compared to sections from WT mice. In contrast, protein levels of matrix metalloproteinase 8 (MMP-8), MMP-9, and MMP-13 were elevated in the cartilage of y/y mice. In addition, chondrocyte apoptosis was elevated in SIRT-1 mutant mice as compared to their WT littermates. Consistent with these observations, protein tyrosine phosphatase 1b was elevated in the y/y mice. CONCLUSION: Our in vivo findings in this animal model demonstrate that mice with defective SIRT-1 also have defective cartilage, with elevated rates of cartilage degradation with age. Hence, normal cartilage homeostasis requires enzymatically active SIRT-1 protein. [less ▲]

Sirtuin inhibition attenuates the production of inflammatory cytokines in lipopolysaccharide-stimulated macrophages.

in Biochemical and Biophysical Research Communications (2012), 420(4), 857-861

In several inflammatory conditions such as rheumatoid arthritis or sepsis, the regulatory mechanisms of inflammation are inefficient and the excessive inflammatory response leads to damage to the host ... [more ▼]

In several inflammatory conditions such as rheumatoid arthritis or sepsis, the regulatory mechanisms of inflammation are inefficient and the excessive inflammatory response leads to damage to the host. Sirtuins are class III histone deacetylases that modulate the activity of several transcription factors that are implicated in immune responses. In this study, we evaluated the impact of sirtuin inhibition on the activation of lipopolysaccharide (LPS)-stimulated J774 macrophages by assessing the production of inflammatory cytokines. The pharmacologic inhibition of sirtuins decreased the production of tumour necrosis factor-alpha (TNF-alpha) interleukin 6 (IL-6) and Rantes. The reduction of cytokine production was associated with decreased nuclear factor kappa B (NF-kappaB) activity and inhibitor kappa B alpha (IkappaBalpha) phosphorylation while no impact was observed on the phosphorylation status of p38 mitogen-activated kinase (p38 MAPK). This work shows that sirtuin pharmacologic inhibitors are a promising tool for the treatment of inflammatory conditions. [less ▲]

Sistema familiare e disturbi del comportamento alimentare: dati preliminari di una ricerca.

in Psichiatria (1999)

Sistema informatizado de ante-proyecto y de proyecto para astilleros de tamano medio y pequeno

Conference (1993, June)

Le site de la Schola du Trajan à Ostia Antica. Chroniques archéologiques sur l'embouchure du Tibre

Conference given outside the academic context (2012)