<i>Pediococcus pentosaceus</i> decreases α-synuclein accumulation and alleviates parkinsonism in <i>Caenorhabditis elegans</i> and <i>Oryzias latipes</i>

In Parkinson's disease (PD), α–synuclein (αSyn) accumulation drives neuropathological progression, establishing it as a potential therapeutic target. Lactic acid bacteria (LAB) provide various health benefits to the host and are expected to offer protective effects on neurological functions through the brain–gut connection, as indicated by animal studies. However, the protective effects of LAB against αSyn are not well understood. We investigated whether LAB feeding could reduce αSyn accumulation and improve mobility in transgenic Caenorhabditis elegans , an invertebrate model organism that expresses human αSyn in muscle. Among the nine screened strains, Pediococcus pentosaceus suppressed αSyn accumulation and the decrease in bending counts, a locomotion index in nematodes. Additionally, feeding P. pentosaceus to Oryzias latipes (medaka), a vertebrate model organism, alleviated PD–like behavioral defects induced by 1–methyl–4–phenyl–1,2,3,6–tetrahydropyridine. P. pentosaseus acts as a probiotic against PD, and PD model worms and medaka can be used to screen effective LAB for prevention.