Figure 4. DAMPs-NLRP3 inflammasome in OC differentiation and function. DAMPs such as MSU are endocytosed into OC precursors where TLRs may have a role. Upon exposure to DAMP, NLRP3 inflammasome is activated and in turn catalyses the conversion of procaspase-1 to caspase-1, which contributes to the production and secretion of the mature IL-1β. The activated caspase-1 also breaks down ARTD1, also known as PARP1, which leads to loss of its inhibitory role against canonical NF-κB signaling. The enhanced NF-κB activity can increase the transcription of IL-1β and NFATc1 that potentiate OC differentiation from OC precursors. In mature OC, NLPR3 inflammasome enhances bone resorbing ability through reorganization of actin cytoskeleton.