Table 1.

regulatory roles of circRNAs in OA

circRNAs	model/ system	Expression	Function	Pathway	Ref
circRNA-UBE2G1	Human cartilage/ C28/I2 cell line	↑	Reducing viability and promoting apoptosis of chondrocytes	circRNA-UBE2G1/ miR-373/ HIF-1a	[80]
circ_0136474	Human cartilage/ primary articular chondrocytes	↑	Inhibiting the proliferation and promoting the apoptosis of chondrocytes	circ_0136474/ MMP-13	[24]
circRNA-CER	Human cartilage/ primary articular chondrocytes	↑	Facilitating chondrocyte ECM degradation	circRNA-CER/ miR-136/ MMP-13	[81]
circVCAN	Human cartilage/ primary articular chondrocytes	↑	Promoting chondrocytes proliferation	circVCAN/ NF-κB	[60]
circPSM3	Human cartilage/ primary articular chondrocytes	↑	Enhancing chondrocytes proliferation and differentiation	circPSM3/ miRNA-296-5p	[59]
hsa_circ_0005105	Human primary articular chondrocytes (IL-1β stimulation)	↑	Promoting ECM degradation	hsa_circ_0005105/ miR-26a/NAMPT	[25]
circRNA-CDR1as	Human cartilage/ primary articular chondrocytes	↑	Modulating ECM metabolism and inflammation of chondrocytes	circRNA-CDR1as//miR-641/FGF-2	[82]
circRNA_Atp9b	Mouse articular chondrocytes (IL-1β stimulation)	↑	Promoting ECM degradation and inflammation of chondrocytes	circRNA_Atp9b/ miR-138-5p	[83]
circRNA.33186	Mouse DMM model/ primary chondrocytes	↑	Suppressing proliferation and promoting ECM degradation	circRNA.33186/ miR-127-5p/ MMP-13	[84]
circGCN1L1	Human TMJ synovial tissue/ primary synoviocyte/ primary chondrocytes	↑	Promoting chondrocytes apoptosis and synoviocyte proliferation	circGCN1L1/ miR-330-3p/ TNF-α	[26]
circ9119	Human cartilage/ SW1353 cell line	↓	Its overexpression protects chondrocytes from apoptosis	circ9119/miR-26a/PTEN	[85]
hsa_circ_0045714	Human cartilage/ primary articular chondrocytes	↓	Its overexpression promotes ECM synesis and chondrocytes proliferation	hsa_circ_0045714/ miR-193b/ IGF-1R	[86]
circSERPINE2	Human cartilage/ Rabbit ACLT model	↓	Its downregulation promotes the apoptosis and ECM degradation	circSERPINE2/ miR-1271/ ERG	[87]
ciRS-7	Human blood sample/ C28/I2 cell line	↓	Its downregulation promotes the secretion of inflammatory cytokines	ciRS-7/ miR-7	[88]

↑upregulation, ↓downregulation, ECM extracellular matrix, ERG E26 transformation-specific (ETS)-related gene, HIF-1a hypoxia-inducible factor-1a, IGF-1R insulin-like growth factor 1 receptor, MMP-13 matrix metalloproteinase 13, NAMPT nicotinamide phosphoribosyl transferase