Adiponectin attenuates the premature senescence of vascular smooth muscle cells induced by high glucose through mTOR signaling pathway.

OBJECTIVE:Cardiovascular diseases and vascular aging are common in patients with diabetes. High glucose is a major cause of vascular aging and cardiovascular diseases. Premature senescence of vascular smooth muscle cells (VSMCs) is one of the main contributors to vascular aging. Adiponectin has been demonstrated to have an anti-aging effect. The present study explored the mechanisms by which adiponectin protects VSMCs against high-glucose-induced senescence. METHODS:Senescence-associated β-galactosidase (SA-β-gal) staining was used to detect senescence cells. Western blot was used for measuring protein levels. Flow cytometry was carried out to detect the cell cycle and telomeric repeat amplification protocol (TRAP)-polymerase chain reaction (PCR) silver staining was selected to measure the telomerase activity. RESULTS:Premature senescence of VSMCs was induced by high glucose (30 mM) in a time-dependent manner, which was verified by an increased number of senescence cells, p21 and p53 expression, as well as the decreased proliferation index. High glucose reduced telomerase activity of VSMCs via inhibition of the AMPK/TSC2/mTOR/S6K1 pathway and activation of the PI3K/Akt/mTOR/S6K1 pathway, while adiponectin treatment significantly increased telomerase activity of VSMCs through activation of AMPK/TSC2/mTOR/S6K1 signaling and inhibition of PI3K/Akt/mTOR/S6K1 signaling. CONCLUSION:Adiponectin attenuated the high-glucose-induced premature senescence of VSMCs via increasing telomerase activity of VSMCs, which was achieved by activation of AMPK/TSC2/mTOR/S6K1 signaling and inhibition of PI3K/Akt/mTOR/S6K1 signaling.