Bifidobacterium longum upregulates mitochondrial activity and suppresses Parkinson’s disease in Caenorhabditis elegans

Bifidobacterium is a probiotic bacterium that has positive effects on human health, including the regulation of intestinal function. This study aimed to identify novel bioactive effects of Bifidobacterium in Caenorhabditis elegans . Previously, we found that Bifidobacterium longum significantly increased the motility of nematodes and, although antioxidant effects are thought to be one of the factors, we hypothesized that B. longum might have affected the muscles and mitochondria, causing an increase in motility. Thus, the purpose of this study was to analyze the bioactive effects and mechanisms of action of B. longum on the muscle and mitochondria of C. elegans . The results showed that B. longum increased the muscle mass, mitochondrial mass, ATP content, mitochondrial membrane potential, and mitochondrial ROS. Furthermore, high-resolution microscopy and qPCR showed that B. longum maintained mitochondrial homeostasis. We also used inhibitors of the mitochondrial complexes to analyze those which were specifically targeted by B. longum . The results implicated mitochondrial complex I, which is closely associated with Parkinson’s disease. Furthermore, B. longum increased the expression of dopaminergic neurons and decreased the expression of α-synuclein in C. elegans . Overall, we showed that B. longum is beneficial to health and has the potential to prevent Parkinson’s disease.