AMPK/TSC2/mTOR pathway regulates replicative senescence of human vascular smooth muscle cells

Area of Science:

• Cellular senescence
• Vascular biology
• Aging research

Background:

• Aging populations are increasing, leading to more age-associated diseases, including vascular conditions.
• Vascular smooth muscle cell (VSMC) replicative senescence contributes to aging and vascular diseases.
• The role of mammalian target of rapamycin (mTOR) signaling in VSMC aging requires further investigation.

Purpose of the Study:

• To investigate the involvement of mTOR signaling in the replicative senescence of human VSMCs.
• To elucidate the specific molecular mechanisms underlying VSMC aging.
• To explore potential interventions targeting the identified signaling pathways.

Main Methods:

• Human VSMCs were subjected to extended passaging to induce replicative senescence.
• Senescence was identified using morphological changes, senescence-associated β-galactosidase activity, and p53/p21 protein expression.
• Western blot analysis was used to assess protein expression and phosphorylation, including key components of the AMPK/TSC2/mTOR/S6K1 pathway.

Main Results:

• Extended passaging led to significant VSMC senescence.
• Senescent VSMCs showed decreased phosphorylation of AMPK/TSC2 and increased phosphorylation of mTOR/S6K1.
• Treatment with an AMPK activator and mTOR inhibitor reversed these phosphorylation changes and delayed senescence.

Conclusions:

• The AMPK/TSC2/mTOR/S6K1 signaling axis plays a critical role in regulating human VSMC replicative senescence.
• Targeting this pathway may offer a strategy to mitigate VSMC aging and related vascular dysfunction.
• Findings provide insights into the molecular basis of age-associated vascular diseases.