As summarized in Fig. 7, the systemic injection of human umbilical cord MSCs (i) inhibited the NLRP3 inflammasome to downregulate the MPTP-induced inflammation in both the central system and periphery and thus (ii) relieved the degenerative changes in dopaminergic neurons in PD mice (Fig. 8). The gene discussed is NLRP3; the disease is Parkinson disease.