Table 1.

The role and function of HMGB proteins in arthritis.

HMGB protein	Disease	Location	Function	Mechanism	References
HMGB1	rheumatoid arthritis	extracellular	synovial inflammation	binds to RAGE, TLR2, and TLR4 to activate the NF-κB	34, 40, 41
	osteoarthritis		cartilage and bone destruction	pathway and signal transduction through JNK and p38	29, 30
	juvenile idiopathic arthritis		induction of proinflammatory cytokine and chemokine expression		31, 32, 33
	crystal-induced arthritis				34
	psoriatic arthritis				35
	spondyloarthritis				36
HMGB2	osteoarthritis	nuclear	chondrocyte survival and homeostasis	binds to LEF1 to enhance Wnt signaling	76
				maintains SZ homeostasis via EFEMP1	95
			suppression of cartilage hypertrophy	binds to LEF1 and RUNX2 to suppress RUNX2 activity	85