Key compounds and mechanisms of Lactiplantibacillus plantarum SCS2 in mitigating oxidative damage in INS-1 cells

Abstract

Objective

This study investigated the key compounds and molecular mechanisms of Lactiplantibacillus plantarum (L. plantarum) SCS2 in reducing oxidative damage induced by hydrogen peroxide in rat insulinoma (INS-1) cells.

Methods

Intracellular peptides of ≤1 kDa from L. plantarum SCS2 were separated, refined, and characterized through liquid chromatography and mass spectrometry. Molecular docking identified peptides with strong binding affinity to Kelch-like ECH-associated protein 1 (Keap1). After employing a siRNA to knock down Keap1 expression, the underlying mechanisms were explored using Western blot and immunofluorescence analyses.

Results

Fifty-three peptides were identified, with PA (SLLFPGGN) and PB (AFDAPIN) showing strong Keap1 binding. PA and PB activated the Keap1–Nuclear factor erythroid 2-associated factor 2 (Nrf2) pathway, increasing Nrf2 and heme oxygenase-1 expression and reducing oxidative damage.

Conclusion

The intracellular peptides PA and PB of L. plantarum SCS2 could ameliorate oxidative damage in INS-1 cells through competitively binding to Keap1, thereby activating the Keap1–Nrf2 pathway.