SNCA and Parkinson disease: Exo@tac can regulate PD-related intestinal bacteria and affect MGBA-related macrophages, neuromicroglia, and intestinal endocrine cells, reducing inflammation and apoptosis in the central nervous system, promoting the production of neurotransmitters 5-HT and the dopamine precursor, as well as reducing deposition of the PD signature protein alpha-synuclein (a-syn).