COG133 ameliorates depression-like behaviors in mice by inhibiting p38 MAPK-mediated neuroinflammation

COG133, a peptide fragment derived from apolipoprotein E (ApoE) corresponding to residues 133-149, has demonstrated significant anti-inflammatory and neuroprotective activity. However, its precise anti-inflammatory mechanisms and its potential to ameliorate depression-like behaviors remain incompletely understood. This study investigated the effects of COG133 in mouse models of depression induced by lipopolysaccharide (LPS), chronic social defeat stress (CSDS), and corticosterone (CORT), as well as in LPS-stimulated BV-2 microglial cells. We found that COG133 treatment significantly alleviated depression-like phenotypes and suppressed hippocampal neuroinflammation by inhibiting microglial overactivation. Using RNA sequencing (RNA-seq) and biochemical validation, we identified the MKK3/6-p38-ATF2 signaling axis as a central mechanism underlying the anti-inflammatory effects of COG133. Pharmacological modulation of p38 MAPK further confirmed that this pathway is essential for COG133-mediated behavioral and cellular recovery. Together, these findings identify COG133 as a promising peptide candidate for the treatment of depression through modulation of the p38 MAPK-mediated neuroinflammation axis.