The NLRP3 molecule influences the therapeutic effects of mesenchymal stem cells through reprogramming energy metabolism

Abstract Background Numerous studies have demonstrated that NLRP3 is involved in the pathogenesis of inflammatory bowel disease (IBD). Mesenchymal stem cells (MSCs) have been highlighted as new candidates for treating IBD based on their immunomodulatory properties, including regulation of the NLRP3 inflammasome. However, the role of NLRP3 in shaping the immunoregulatory function of MSCs remains unclear. In this study, we demonstrated that NLRP3 influences the therapeutic effect of MSCs on colitis in an inflammasome-independent manner. Methods MSCs were isolated from the femurs of male C57/B6 mice or Nlrp3 KO mice, identified by osteogenic adipogenic differentiation assay and flow cytometry. In vitro, WT and Nlrp3 KO MSCs were treated with LPS, then the supernatant was collected; WT MSCs were stimulated with different concentrations of NLRP3-specific inhibitor MCC950, and the level of IL-10 was detected in the supernatant; Detect gene expression levels by RNA sequencing; Use Seahorse to detect cellular oxidative phosphorylation (OXPHOS) and glycolysis levels; The expression of glucose transporter 1 (Glut1) in MSCs was detected by Western blot; WT MSCs were stimulated with different concentrations of Glut1 inhibitor BAY876, and the level of IL-10 was detected. In vivo, DSS-induced colitis was treated with WT or Nlrp3 KO MSCs, body weight changes were monitored daily, measure colon length and collect colons for further evaluation; Then DSS-induced colitis was treated with pretreated MSCs, such as BAY876 pretreated WT MSCs or Glut1-overexpressed Nlrp3 KO MSCs (OE-Glut1), then the experimental operation is as above. Results Nlrp3 knockout did not alter MSC phenotypes, but promoted osteogenic differentiation. Further investigation indicated that deletion of Nlrp3reduced the production of the IL-10 in MSCs, leading to an impaired protective effect on DSS-induced colitis. Mechanistically, the deficiency of Nlrp3 downregulated Glut1 expression and glycolysis activation in MSCs, which reduced IL-10 production. Subsequently, overexpressing Glut1 in Nlrp3 KO MSCs recovered their therapeutic effect dampened due to Nlrp3 deletion. Conclusions These results improve the current understanding of the molecular mechanisms underlying the therapeutic effectiveness of MSCs and provide a basis for optimizing MSC-based therapeutic strategies for immune-mediated diseases.