Abstract
Background Inflammasomes are cytosolic, multiprotein complexes which act at the frontline of the immune responses by recognizing pathogen or danger-associated molecular patterns of pathogens or abnormal host molecules. Mesenchymal stem cells (MSCs) have been reported to possess multipotency to differentiate into various cell types and immunoregulatory effects which make them a promising treatment for regenerative medicine and immune-related diseases, respectively. However, little is known about the expression and role of the inflammasome in adult stem cells. In this study, we investigated the expression and functional regulation of NLRP3 inflammasome in human umbilical cord blood-derived MSCs (hUCB-MSCs). Methods The expression of NLR Family Pyrin Domain Containing 3 (NLRP3) inflammasome was detected in hUCB-MSCs. Cell proliferation, death and differentiation were analyzed after NLRP3 inflammasome activation. To investigate the changes in immunoregulatory functions of hUCB-MSCs, naïve or NLRP3 inflammasome-stimulated cells were infused into chemically induced colitic mice and symptoms were monitored. Results NLRP3 inflammasome activation suppressed the differentiation of hUCB-MSCs into osteoblasts, which was restored when the expression of adaptor proteins for inflammasome assembly was inhibited. Moreover, the suppressive effects of MSCs on T cell responses and the macrophage activation were augmented in response to NLRP3 activation. In vivo studies using colitic mice revealed that the protective abilities of hUCB-MSCs increased after NLRP3 stimulation. Conclusions Our findings suggest that the NLRP3 inflammasome components are expressed in hUCB-MSCs and its activation can regulate the differentiation capability and the immunomodulatory effects of hUCB-MSCs.
Single-stage cell-based cartilage repair in a rabbit model: cell tracking and in vivo chondrogenesis of human umbilical cord blood-derived mesenchymal stem cells and hyaluronic acid hydrogel composite