Microarray expression and functional analysis of circular RNAs in the glomeruli of NZB/W F1 mice with lupus nephritis

The present study applied a circular RNA (circRNA) microarray to examine the circRNA expression profiles in the glomeruli of NZB/W F1 mice with lupus nephritis (LN) during the pathogenesis of the disease. Glomeruli from two groups of female NZB/W F1 mice of the same age with either severe or mild LN were isolated by perfusion with dynabeads. A microarray analysis was then performed to evaluate the differentially expressed circRNAs of the glomeruli in the two groups, which were then confirmed by reverse transcription-quantitative PCR (RT-qPCR) assays. In addition, using a biomathematical strategy, the differentially-expressed circRNAs were identified in severe LN when compared with mild LN, and the commonly expressed circRNA species among these profiles were optimized via competing endogenous RNA (ceRNA) analysis. The predicted microRNAs (miRNAs/miRs) as downstream targets of circRNAs and upstream regulators of mRNAs were verified by RT-qPCR and the final circRNA-miRNA-mRNA network was constructed to identify the circRNA that was a pathogenic link in LN. The present study obtained 116 differentially expressed circRNAs, including 41 up- and 75 downregulated circRNAs, in severe LN when compared with mild LN, and 12 circRNAs were confirmed by RT-qPCR. The most significant difference was in the expression of mmu_circRNA_34428 (P<0.001) when comparing severe and mild LN glomeruli. A network of mmu_circRNA_34428-targeted miRNA-gene interactions was subsequently constructed, including miR-338-3p, miR-670-3p, miR-3066-5p, miR-210-5p and their corresponding mRNA targets. To the best of our knowledge, the present study elucidated, for the first time, circRNA profiling and the circRNA-miRNA interactions in the development of LN in female NZB/W F1 mice. The results revealed that mmu_circRNA_34428 could serve an important role in LN progression; however, the present study did not elucidate the functions of this circRNA or others in LN progression.