Table 2.

Overview of the most relevant circRNAs in OA.

circRNA	Expression in OA	Target miRNAs	Effective Role	Species	References
circRNA_Atp9b	↑	miR-138-5p	↓ Col II	Mouse	[147,148]
			↑ Mmp-13, Cox-2, Il-6
circRNA-CER	↑	miR-636 miR-665 miR-217 miR-646 miR-136	↑ MMP13 expression by binding miR-136	Human	[145]
circSERPINE2	↓	miR-1271	↑ MMP-3, MMP-13, ADAMTS4	Human/Rabbit	[149]
			↓ SOX-9, COL II, ACAN
			IA injection → Attenuation of OA, ↑ ECM anabolism
ciRS-7	↓	miR-7	↑Apoptosis and inflammation	Human	[152]
circ_0045714	↓	miR-218-5p	↓IL-6, IL-8, MMP-13, ADAMTS-4 ↑COL II, ACAN	Human	[139]
circ_0136474	↑	miR-127-5p	↑ MMP-13, apoptosis	Human	[146]
			↓ Cell proliferation
circ_0104873	↑		Positively correlated with radiographic and symptomatic OA severity
circ_0104595	↑	-		Human	[150]
circ_0101251	↑