Peptide from tempeh-like fermented Chenopodium formosanum counters senescence while enhancing antioxidant ability in non-replicative aging

The study assesses the protective effects of glycine-rich peptide (GRP) from tempeh-like fermented Chenopodium formosanum against non-replicative aging. By pretreating Hs68 cells with GRP and irradiating them with UVA, a reduction in oxidative stress was observed which positively contributed to cell survival rate. Moreover, transcriptomic analysis demonstrated that pretreatment with GRP prevents the downregulation of oxidative stress responses and an upregulated expression of cell cycle. Additionally, GRP was found to increase the expression of Nrf2 pathway while decreasing the expressions of p53 and p21. These findings were further investigated in Caenorhabditis elegans, where GRP treatment could extend lifespans and improve resistance to oxidative stress. Finally, molecular docking studies indicated GRP binds to the KEAP-BTB inhibitory site inhibitory site, potentially inhibiting activity of single O-linked β-N-acetylglucosamine transferase which facilitates activation of Nrf2 pathway. These results highlight the capability of GRP as a protective agent against oxidative stress and non-replicative aging.