circRTN4 mediates glomerulosclerosis in lupus nephritis by regulating monocyte-derived TNF-α
Objective:To investigate whether hsa_circ_0054595(circRTN4)is involved in glomerulosclerosis of lupus nephri-tis(LN)by regulating monocyte-derived TNF-α.Methods:RT-qPCR and immunofluorescence were used to detect the expression of TNF-α in monocytes of LN patients,and fluorescence in situ hybridization(FISH)was used to detect the expression of circRTN4.THP1 cells were transfected with circRTN4-siRNA and negative control NC-siRNA,respectively.RT-qPCR and Western blot were used to detect the expression of TNF-α in THP1cell,and ELISA was used to detect the expression of TNF-α in THP1 culture superna-tant.THP1 cells were transfected with mircoRNA mimics,and the expression of TNF-α was detected by Western blot.The direct bind-ing of miR-486-3p to TNF-α and circRTN4 were verified by reversion experiment and dual luciferase reporter gene experiment.MRL/lpr mice were injected with circRTN4 recombinant adeno-associated virus via tail vein,and the expression of circRTN4 in peripheral blood mononuclear cells of the mice was detected by RT-qPCR.ELISA was used to detect the expression of serum TNF-α.HE staining and PAS staining were used to observe the pathological changes,and immunofluorescence was used to detect the expression of FN.Results:The expressions of TNF-α and circRTN4 were increased in monocytes of LN patients(P<0.05).The expression of TNF-α in THP1 was significantly increased in the LN group(P<0.01).Knockdown of circRTN4 inhibited the expression and secretion of TNF-α(P<0.05),and this effect was achieved by binding to miR-486-3p(P<0.01).In vivo,knockdown of circRTN4 in peripheral blood monocytes of MRL/lpr mice reduced the expression of TNF-α in serum(P<0.05),and improved glomerular cell proliferation and FN deposition.Conclusion:Highly expressed circRTN4 in monocytes promotes the expression of TNF-α by binding to miR-486-3p,and participates in the occurrence and development of glomerulosclerosis in LN.