Sargahydroquinoic acid (SHQA) suppresses cellular senescence through Akt/mTOR signaling pathway

AIM: The effects of sargahydroquinoic acid (SHQA) on cellular senescence and the underlying mechanisms were investigated using human umbilical vascular endothelial cells (HUVECs). METHODS: SHQA or DMSO was supplemented into the medium. Low dose of H₂O₂ was used to induce premature senescence. Replicative senescence was achieved by continuously culturing cells until they reached a plateau phase. Senescence biomarkers, including p53, p21, and p16 proteins, and SA-β-Gal activity were measured. RESULTS: Pretreatment of SHQA significantly suppressed the oxidative stress-induced protein expression of p53, p21, and p16, as well as the activity of SA-β-Gal. Additionally, SHQA also delayed the replicative senescence as indicated by an increased population doubling number, reduced protein expression of p53, p21, and p16, as well as a decreased SA-β-Gal activity. SHQA inhibited the phosphorylation of Akt, mTOR, and downstream targets of mTOR, such as p-S6K, which was elevated by premature senescence and replicative senescence. In the absence of senescence stimuli, SHQA also inhibited the Akt/mTOR signaling pathway and promoted autophagy. CONCLUSIONS: SHQA suppressed senescence induced by oxidative stress and replication through inhibiting the Akt/mTOR pathway. With the potential of acting as an Akt/mTOR inhibitor, SHQA might be useful for developing anti-ageing therapy.