Nature Microbiology, Published online: 30 July 2026; doi:10.1038/s41564-026-02433-0 Lactiplantibacillus plantarum-derived fatty-acid metabolite, 10-hydroxystearic acid, interacts directly with PPARα to alter histone crotonylation and the transcriptional landscape which leads to gut barrier functional repair and enhanced viral suppression in non-human primate models when combined with anti-retroviral therapy.