GCG and Parkinson disease: Sun et al. demonstrated that Clostridium butyricum supplementation in MPTP (1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine)-induced PD mice decreased motor deficits and reversed proinflammatory microglial phenotypes and neuroinflammation through GM modulation and enhancing glucagon-like peptide-1 (GLP-1) signaling (Sun et al., 2021).