Lactiplantibacillus plantarum as a Psychobiotic Strategy Targeting Parkinson's Disease: A Review and Mechanistic Insights.

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by the pathological aggregation of α-synuclein (α-syn), the loss of dopaminergic neurons, and the appearance of both motor and non-motor symptoms. Emerging evidence suggests a bidirectional influence of the microbiota-gut-brain axis in PD pathogenesis, where gut dysbiosis contributes to increased intestinal barrier permeability, immune activation, chronic inflammation, oxidative stress, α-syn misfolding, and neurotransmitter imbalance. These findings are increasing interest in probiotics as microbiota-targeted interventions that restore intestinal and systemic homeostasis. Lactiplantibacillus plantarum, a probiotic species with remarkable environmental adaptability and genomic plasticity, has emerged as a promising candidate for PD management. Preclinical studies demonstrate that specific Lpb. plantarum strains, such as PS128 or CCFM405, can beneficially modulate gut microbial communities, reinforce barrier integrity, regulate bile acid metabolism, attenuate neuroinflammatory responses, and improve motor deficits in PD-like mice. In addition, Lpb. plantarum DP189 or SG5 interventions can significantly reduce α-syn aggregation in the brain via suppression of oxidative stress, modulation of neuroinflammatory responses, and activation of neurotrophic factors. Recent evidence even suggests that Lpb. plantarum-derived extracellular vesicles may possess anti-PD activity by influencing host gene expression, neuronal function, and immune modulation. Although robust clinical data are still limited, preliminary clinical trials indicate that supplementation with PS128 or certain Lpb. plantarum-contained consortiums can alleviate constipation, improve gastrointestinal function, reduce systemic inflammation, and even ameliorate motor symptoms when used alongside standard dopaminergic therapies. In this review, we provide an integrated overview of preclinical, clinical, and mechanistic insights, and evaluate the translational potential of Lpb. plantarum as a safe and diet-based strategy to target the microbiota-gut-brain axis in PD.