Fig. 2.

Schematic of NF-κB signalling in macrophages during early inflammation in endochondral ossification. A Downregulation of SIRT1 expression disinhibits acetylation of RelA/P65, increasing RelA/P65 activity to promote NF-κB-dependent inflammatory gene expression (TNF-α and IL-6). B Downregulation of AMPK expression enhances RelA/P65 activity, enlarging NF-κB-dependent gene transcription (IL-10 and MCP-1). C Inactive macrophages can be stimulated to an active state via cytokine-receptor binding, promoting NLRP3 and pro-IL-1β expression. Active NLRP3 inflammasome activates caspase-1 to convert pro-IL-1β into IL-1β, further promoting chondrogenesis (Created with BioRender.com)