Author + information
- Chunmei Tang,
- Jiening Zhu,
- Qiuxiong Lin,
- Shulin Wu and
- Zhixin Shan
Circular RNAs (circRNAs) participate in regulating gene expression in diverse biological and pathological processes. The present study aimed to investigate the mechanism underlying the modulation of circRNA_000203 on expressions of fibrosis-associated genes in cardiac fibroblasts.
Masson trichrome staining was performed on the myocardium of the diabetic db/db mice and the nondiabetic db/m control mice. CircRNAs expression profile in the diabetic myocardium was detected by circRNAs microarray, followed with the identification of circRNA_000203 expression by quantitative reverse transcription PCR (RT-qPCR). Dual luciferase reporter assay was used to confirm the target genes of miR-26b. Expressions of Col1a2, Col3a1and other concerned genes were determined by RT-qPCR and western-blot assay, respectively.
CircRNA_000203 was shown upregulated in the diabetic mouse myocardium and TGF-β1-induced mouse cardiac fibroblasts. Enforced-expression of circRNA_000203 could increase expressions of Col1a2, Col3a1 and α-SMA in mouse cardiac fibroblast. Bioinformatics analysis indicated that microRNA-26b (miR-26b) has two potential binding sites in circRNA_000203, Col1a2 and CTGF were candidate targets of miR-26b. Dual luciferase reporter assay revealed that miR-26b interacted with 3′UTRs of Col1a2 and CTGF, and circ_000203 could block the interactions of miR-26b and 3′UTRs of Col1a2 and CTGF. Transfection of miR-26b could post-transcriptionaly inhibit expressions of Col1a2 and CTGF, accompanied with the suppressions of Col3a1 and α-SMA in cardiac fibroblasts. Additionally, over-expression of circRNA_000203 could eliminate the anti-fibrosis effect of miR-26b in cardiac fibroblasts.
Suppression of the function of miR-26b contributes to the pro-fibrosis effect of circRNA_000203 in cardiac fibroblasts.