β-Ecdysterone attenuates Ang II-induced senescence in human aortic smooth muscle cells via AKT/mTOR inhibition.

Vascular aging, characterized by cellular senescence in vascular smooth muscle cells (VSMCs), is a critical contributor to cardiovascular diseases. Angiotensin II (Ang II), a key player in hypertension, is known to induce premature senescence in these cells, leading to impaired vascular function. Current therapeutic strategies often fall short in directly targeting cellular senescence pathways. Understanding novel compounds that can mitigate Ang II-induced senescence by modulating pathways like autophagy and reactive oxygen species (ROS), potentially through the AKT/mTOR pathway, offers a promising avenue for preventing age-related vascular dysfunction.

Researchers induced senescence in human aortic smooth muscle cells (HASMCs) using angiotensin II (Ang II). These senescent cells were then treated with β-Ecdysterone (β-Ecd) at concentrations up to 200 μM. Cell viability was assessed via CCK-8 assay. Senescence was quantified using SA-β-gal staining, cell cycle analysis, and western blotting for p53 and p21. Inflammatory cytokine levels (IL-6, MCP-1) were measured by ELISA. Autophagy was evaluated through LC3 immunofluorescence, autolysosome staining, and western blotting for LC3 and p62. Intracellular ROS levels were determined by flow cytometry. Transcriptomic profiling and molecular docking were used to explore mechanisms, with key findings validated by western blot.

Ang II treatment successfully induced pronounced senescence in HASMCs, marked by increased SA-β-gal activity, elevated expression of p53 and p21, G0/G1 cell cycle arrest, impaired autophagic flux, increased ROS accumulation, and heightened secretion of IL-6 and MCP-1. CCK-8 assays confirmed that β-Ecd did not negatively impact HASMC viability at concentrations up to 200 μM. Treatment with 200 μM β-Ecd effectively attenuated Ang II-induced senescence, demonstrating a restoration of normal cell cycle distribution, a reduction in p53 and p21 expression, and a suppression of IL-6 and MCP-1 secretion. β-Ecd also significantly enhanced autophagic activity, evidenced by increased LC3II levels, reduced p62 accumulation, and enhanced autophagosome-lysosome fusion. Furthermore, β-Ecd significantly decreased Ang II-induced ROS accumulation.

Transcriptomic analysis and validation revealed that β-Ecd exerted its protective effects by inhibiting the AKT/mTOR pathway, which subsequently led to autophagy activation and ROS suppression.