Sun et al. (2021) found that supplementation with Clostridium butyricum in MPTP-induced PD mice increased the number of SCFA-producing bacteria, promoted GLP-1 secretion by intestinal endocrine L cells, and activated the GLP-1 receptor in the brain, thereby improving dopaminergic neuron loss and neuroinflammation. This evidence concerns the gene GLP1R and Parkinson disease.