Bioactive Oligopeptides from Ginseng (Panax ginseng Meyer) Suppress Oxidative Stress-Induced Senescence in Fibroblasts via NAD+/SIRT1/PGC-1α Signaling Pathway

The physicochemical properties and multiple bioactive effects of ginseng oligopeptides (GOPs), plant-derived small molecule bioactive peptides, suggest a positive influence on health span and longevity. Given this, cellular senescence is the initiating factor and key mechanism of aging in the organism, and thus the current study sought to explore the effects of GOPs on H2O2-induced cellular senescence and its potential mechanisms. Senescence was induced in mouse embryonic fibroblasts NIH/3T3 by 4 h of exposure to 200 µM H2O2 and confirmed using CCK-8 assay and Western blot analyses of p16INK4A and p21Waf1/Cip1 after 24 h of growth medium administration with or without GOPs supplementation (25, 50, and 100 µg/mL). We found that GOPs delayed oxidative stress-induced NIH/3T3 senescence by inhibiting the G1 phase arrest, increasing DNA synthesis in the S phase, decreasing the relative protein expression of p16INK4A and p21Waf1/Cip1, promoting cell viability, protecting DNA, and enhancing telomerase (TE) activity. Further investigation revealed that the increase in antioxidative capacity and anti-inflammation capacity might form the basis for the retarding of the senescence effects of GOPs. Furthermore, GOPs supplementation significantly improved mitochondrial function and mitochondrial biogenesis via the NAD+/SIRT1/PGC-1𝛼 pathway. These findings indicate that GOPs may have a positive effect on health span and lifespan extension via combating cellular senescence, oxidative stress, and inflammation, as well as modulating longevity regulating pathway NAD+/SIRT1/PGC-1𝛼.