2022, Vol. 26 ›› Issue (20): 3141-3146

A circular RNA, circ_0040646, regulates the proliferation, differentiation, and apoptosis of knee osteoarthritis chondrocytes by targeted inhibition of microRNA-188-3p

Zhang Xuepu, Wu Yuexin, Zhao Haosen, Ban Zhaoliang, Ma Xiaohu, Tong Gang, Yang Limin   

Abstract: BACKGROUND: Circular RNAs play an important regulatory role in various diseases. Recent studies have shown that circular RNAs are abnormally expressed in knee osteoarthritis. Therefore, it is very essential to study the effect of circular RNAs on the pathogenesis of knee osteoarthritis.
OBJECTIVE: To investigate the effect of circ_0040646 regulating microRNA-188-3p (miR-188-3p) on the proliferation, differentiation and apoptosis of knee osteoarthritis chondrocytes.
METHODS: Quantitative real-time fluorescence PCR was used to detect the expression level of circ_0040646 in knee osteoarthritis patients and knee osteoarthritis chondrocytes, in comparison with normal chondrocytes from meniscal injury patients. Chondrocytes from knee osteoarthritis patients were transfected with small-interfering negative control (lowly expressed circ_0040646 control plasmid), small-interfering circ_0040646, overexpressed negative control (overexpressed circ_0040646 control plasmid), overexpressed circ_0040646, miRNA negative control (control group), or microRNA-188-3p inhibitor. Quantitative real-time fluorescence PCR and western blot were used to detect the expression levels of proliferating cell nuclear antigen, bone morphogenetic protein 2 and runt-related transcription factor 2. Flow cytometry was used to detect cell apoptosis. Dual luciferase reporter assay was used to detect the targeted binding of circ_0040646 and miR-188-3p.   
RESULTS AND CONCLUSION: Compared with the control group, circ_0040646 was highly expressed in knee osteoarthritis patients and knee osteoarthritis chondrocytes. In knee osteoarthritis chondrocytes, the low expression of circular RNA-0040646 could promote cell proliferation and differentiation, and inhibit cell apoptosis, while overexpression of circ_0040646 could inhibit cell proliferation and differentiation, and promote cell apoptosis. circ_0040646 could target miR-188-3p in knee osteoarthritis chondrocytes. Co-transfection of small-interfering circ_0040646 and miR-188-3p inhibitors could reverse the effect of small-interfering circ_0040646 alone on the proliferation, differentiation and apoptosis of knee osteoarthritis chondrocytes. These findings reveal that circ_0040646 can regulate the proliferation, apoptosis and differentiation of knee osteoarthritis chondrocytes by targeted inhibition of miR-188-3p, and therefore, circ_0040646 may become a target for the treatment of knee osteoarthritis.
Key words: osteoarthritis, knee joint, circ_0040646, miR-188-3p, proliferation, differentiation, apoptosis