Table 1.

Summary of miRNAs, their targets, expression, and effects on osteoclast differentiation

miRNAs	species	Target gene(s)	Endogenous miRNA expression	miRNA function	Related disease(s)	References
miR-21	mouse	FasL PDCD4	Upregulated in RANKL-induced osteoclastogenesis	Enhances osteoclast differentiation Inhibits osteoclast apoptosis	Postmenopausal osteoporosis; osteoporosis	23,25
miR-29a	rat	Not mentioned	Reduced expression in glucocorticoid-induced bone loss	Inhibits GC-induced osteoclast differentiation	Glucocorticoid-induced bone loss	33
miR-29b	human	c-Fos, MMP2	Downregulated in RANKL induced osteoclastogenesis	Inhibits osteoclast differentiation	Multiple myeloma-related bone disease	34
miR-29	mouse	CDC42 SRGAP2 NFIA, CD93 CALCR	Increased during osteoclast differentiation	miR-29 family member that sustains migration and commitment of precursors to osteoclastogenesis	Possibly related to increased osteoclast formation with aging	35
miR-223	mouse	Not mentioned	Downregulated in osteoclast differentiation	Overexpression completely blocks osteoclast formation	Might be related to bone metabolic disorders	14,52
	human	NFIA	Downregulated in osteoclast differentiation	Inhibits osteoclast differentiation	Bone destruction in rheumatoid arthritis	53
miR-378	mouse	Not mentioned	Upregulated in osteoclast differentiation	Not mentioned	Osteolytic bone metastasis	14,64
miR-146a	mouse	Not mentioned	Downregulated upon RANKL treatment upregulated upon TNF-α/RANKL treatment	Suppresses osteoclastogenesis	Not mentioned	14
	human	TRAF6	Not mentioned	Inhibits PBMC differentiation into osteoclast	Joint destruction in arthritis	49
miR-133a	human	CXCL11 CXCR3 SLC39A1	Up-regulated in low BMD postmenopausal women	Not mentioned	Postmenopausal osteoporosis	46
miR-503	human	RANK	Markedly reduced in postmenopausal osteoporosis women	Inhibits RANKL-induced osteoclast differentiation	Postmenopausal osteoporosis	59
miR-31	mouse	RhoA	Highly upregulated during osteoclast development upon RANKL stimulation	promote ring-shaped mature osteoclasts formation, attributed to cytoskeleton organization	Not mentioned	38
miR-124	mouse	NFATc1 RhoA Rac1	Decreased rapidly upon stimulation of BMMs with RANKL	Negatively regulates osteoclastogenesis, reduces the proliferation and motility of osteoclast precursors	Not mentioned	42
miR-125a	human	TRAF6	Dramatically downregulated during osteoclastogenesis	Inhibit osteoclastogenesis	May be involved in metabolic disease	67,68
miR-148a	Human mouse	MAFB	Upregulated during osteoclast differentiation	Promote osteoclastogenesis	Osteoporosis, contributes to low BMD in lupus patients	67
miR-155	mouse	SOCS1 MITF SHIP	RANKL treatment suppress miR-155 levels in BMMs from Dicer-deficient mice	Suppress osteoclast differentiation	Osteoclast-mediated diseases	15,76,77
miR-422a	human	CBL CD226 IGF1 PAG1 TOB2	Upregulated with marginal significance in the low BMD postmenopausal women	Not mentioned	Postmenopausal osteoporosis	80

*Italics: potential targets