Moreover, the presence of HCAR2 (also known as GPR109A or niacin receptors) on the luminal site of enterocytes, which are also largely expressed throughout the intestine and colon [92], allows MMF to exert its anti-inflammatory effects already at the intestinal level, as, for example, in the restoration of the intestinal barrier in Parkinson’s disease model [93]. The gene discussed is HCAR2; the disease is Parkinson disease.