CircRNA circ‐IQGAP1 Knockdown Alleviates Interleukin‐1β‐Induced Osteoarthritis Progression via Targeting miR‐671‐5p/TCF4

Abstract

Objective To explore the function of circular RNA IQ motif‐containing GTPase‐activating protein 1 (circ‐IQGAP1) in interleukin (IL)‐1β‐induced osteoarthritis (OA) model and to explore whether circ‐IQGAP1 can modulate microRNA‐671‐5p (miR‐671‐5p) and transcription factor 4 (TCF4) to regulate chondrocyte apoptosis, inflammatory injury, and extracellular matrix degradation. Methods The cartilage tissues were collected from 32 OA patients or normal subjects. Human chondrocyte CHON‐001 cells were challenged via different doses of IL‐1β for 24 hours. CHON‐001 cells were transfected with circ‐IQGAP1 overexpression vector, TCF4 overexpression vector, small interfering RNA (siRNA) for circ‐IQGAP1, miR‐671‐5p mimic, miR‐671‐5p inhibitor or corresponding negative controls. Circ‐IQGAP1, miR‐671‐5p and TCF4 abundances in cartilage tissues or CHON‐001 cells were examined via quantitative reverse transcription polymerase chain reaction (qRT‐PCR) or western blot. Cell viability was investigated by 3‐(4, 5‐dimethylthiazol‐2‐yl)‐2, 5‐diphenyltetrazolium bromide (MTT). Cell apoptosis was measured by flow cytometry. The inflammatory injury was analyzed by the secretion levels of inflammatory cytokines (IL‐6, IL‐8 and tumor necrosis factor‐α [TNF‐α]) by enzyme‐linked immunosorbent assay (ELISA). The extracellular matrix degradation was evaluated by expression of aggrecan and matrix metalloproteinase 13 (MMP13) via western blot. The target relationship of miR‐671‐5p and circ‐IQGAP1 or TCF4 was analyzed via dual‐luciferase reporter and RNA immunoprecipitation (RIP) analyses. Results Circ‐IQGAP1 abundance was enhanced in the cartilage tissues from OA patients compared with normal subjects (n = 32), and its expression was increased in CHON‐001 cells after treatment of IL‐1β in a dose‐dependent pattern. MiR‐671‐5p expression was decreased in the cartilage tissues from OA patients (n = 32) and IL‐1β‐challenged CHON‐001 cells. MiR‐671‐5p expression was negatively associated with circ‐IQGAP1 level in OA patients. Circ‐IQGAP1 silence mitigated IL‐1β‐caused chondrocyte viability reduction, apoptosis promotion, secretion of inflammatory cytokine (IL‐6, IL‐8 and TNF‐α), and extracellular matrix degradation (reduction of aggrecan and increase of MMP13). MiR‐671‐5p was targeted and inhibited via circ‐IQGAP1. MiR‐671‐5p knockdown attenuated the influence of circ‐IQGAP1 interference on IL‐1β‐caused chondrocyte apoptosis, inflammatory injury, and extracellular matrix degradation. TCF4 was targeted via miR‐671‐5p, and TCF4 expression was increased in the cartilage tissues from OA patients (n = 32) and IL‐1β‐challenged CHON‐001 cells. TCF4 abundance in OA patients was negatively correlated with miR‐671‐5p expression. MiR‐671‐5p overexpression alleviated IL‐1β‐mediated chondrocyte apoptosis, inflammatory injury, and extracellular matrix degradation via decreasing TCF4 expression. Circ‐IQGAP1 silence reduced TCF4 expression via regulating miR‐671‐5p in IL‐1β‐challenged CHON‐001 cells. Conclusion Circ‐IQGAP1 knockdown attenuated IL‐1β‐caused chondrocyte a...

Circ_0043947 contributes to interleukin 1β-induced injury in chondrocytes by sponging miR-671-5p to up-regulate RTN3 expression in osteoarthritis pathology

“…For instance, circ-SERPINE2 is reported to restrain OA progression by regulating miR-1271 and ETS-associated molecules [25]. Circ-IQGAP1 silencing is reported to attenuate IL-1β-mediated OA development by targeting miR-671-5p/TCF4 axis [26].…”

“…Zhang et al found that miR-671 attenuates OA development in vitro and in vivo [17]. Xi et al found that miR-671-5p is down-regulated in chondrocytes induced by IL-1β, and circ-IQGAP1 contributes to IL-1β-induced OA development by down-regulating miR-671-5p and up-regulating TCF4 [26]. Consistent with these studies, we found that miR-671-5p overexpression protected chondrocytes from IL-1β-induced injury in chondrocytes.…”

Identification of microRNA–mRNA–TF regulatory networks in periodontitis by bioinformatics analysis

“…Furthermore, Wang et al showed that miR-203 inhibits inflammation to alleviate myocardial ischaemia–reperfusion injury [ 37 ]. It has been reported that miR-671-5p represses cell proliferation, migration, invasion and the inflammatory response [ 38 ]. MiR-671 mimics ameliorated IL-1β-induced proliferation inhibition and apoptosis stimulation and alleviated the progression of osteoarthritis in mice [ 39 ].…”

Research progress on the role and mechanism of miR-671 in bone metabolism and bone-related diseases

“…Upstream circRNA usually acts as a miRNA sponge in cells and weakens the inhibitory effect of miR-671 on inflammation through the competitive binding of miR-671. Compared with healthy people, the expression of circ-IQGAP1 and circ_0114876 increases in cartilage tissues, while the expression of miR-671-5p decreases ( 41 ). Reducing circRNA content can reduce chondrocyte apoptosis, inflammatory cytokine secretion, and extracellular matrix degradation induced by IL-1β.…”