Peroxisome proliferator-activated receptor γ coactivator-1α is a central negative regulator of vascular senescence.

Arterioscler Thromb Vasc Biol 2013 May 21;33(5):988-98. Epub 2013 Feb 21.

Division of Cardiology, Emory University Hospital, Emory University School of Medicine, Atlanta, GA, USA.

Objective: Cellular senescence influences organismal aging and increases predisposition to age-related diseases, in particular cardiovascular disease, a leading cause of death and disability worldwide. Peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) is a master regulator of mitochondrial biogenesis and function, oxidative stress, and insulin resistance. Senescence is associated with telomere and mitochondrial dysfunction and oxidative stress, implying a potential causal role of PGC-1α in senescence pathogenesis.

Approach And Results: We generated a PGC-1α(+/-)/apolipoprotein E(-/-) mouse model and showed that PGC-1α deficiency promotes a vascular senescence phenotype that is associated with increased oxidative stress, mitochondrial abnormalities, and reduced telomerase activity. PGC-1α disruption results in reduced expression of the longevity-related deacetylase sirtuin 1 (SIRT1) and the antioxidant catalase, and increased expression of the senescence marker p53 in aortas. Further, angiotensin II, a major hormonal inducer of vascular senescence, induces prolonged lysine acetylation of PGC-1α and releases the PGC-1α-FoxO1 complex from the SIRT1 promoter, thus reducing SIRT1 expression. The phosphorylation-defective mutant PGC-1α S570A is not acetylated, is constitutively active for forkhead box O1-dependent SIRT1 transcription, and prevents angiotensin II-induced senescence. Acetylation of PGC-1α by angiotensin II interrupts the PGC-1α-forkhead box O1-SIRT1 feed-forward signaling circuit leading to SIRT1 and catalase downregulation and vascular senescence.

Conclusions: PGC-1α is a primary negative regulator of vascular senescence. Moreover, the central role of posttranslational modification of PGC-1α in regulating angiotensin II-induced vascular senescence may inform development of novel therapeutic strategies for mitigating age-associated diseases, such as atherosclerosis.

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Source
http://dx.doi.org/10.1161/ATVBAHA.112.301019DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3663327PMC
May 2013

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