NLRP3 and Parkinson disease: In response to MPTP, caspase-1 and NLRP3 mRNA expression markedly increased in the intestinal tissue of PD mice (Fig. 6C and D, P < 0.05 versus control); levels were completely restored by VSL#3, hMSCs, and their combination to levels comparable to those in control mice (P < 0.01 versus PD).