Identification of Plasma hsa_circ_0001230 and hsa_circ_0023879 as Potential Novel Biomarkers for Focal Segmental Glomerulosclerosis and circRNA-miRNA-mRNA Network Analysis

Abstract

Introduction: Focal segmental glomerulosclerosis (FSGS) is a common glomerulopathy with an unclear mechanism. The demand for FSGS clinical diagnostic biomarkers has not yet been met. Circular RNA (circRNA) is a novel non-coding RNA with multiple functions, but its diagnostic value for FSGS remains unexplored. This study aimed to identify circRNAs that could aid in early clinical diagnosis and to investigate their mechanisms in podocyte injury. Methods: The signature of plasma circRNAs for FSGS was identified by circRNA microarray. The existence of circRNAs was confirmed by quantitative real-time polymerase chain reaction (qRT-PCR), RNase R assay, and DNA sequencing. Plasma levels of circRNAs were evaluated by qRT-PCR. The diagnostic value was appraised by the receiver operating characteristic curve. The circRNA-miRNA-mRNA network was built with Cytoscape 7.3.2. Statistically significant differences were calculated by the Mann-Whitney U test. Results: A total of 493 circRNAs (165 upregulated, 328 downregulated) were differentially expressed in the plasma of FSGS patients (n = 3) and normal controls (n = 3). Eight candidate circRNAs were demonstrated to be circular and stable transcripts. Among them, hsa_circ_0001230 and hsa_circ_0023879 were significantly upregulated in FSGS patients (n = 29) compared to normal controls (n = 51). The areas under the curve value of hsa_circ_0001230 and hsa_circ_0023879 were 0.668 and 0.753, respectively, while that of the two-circRNA panel was 0.763. The RNA pull-down analysis revealed that hsa_circ_0001230 and hsa_circ_0023879 could sponge hsa-miR-106a. Additionally, hsa_circ_0001230 and hsa_circ_0023879 positively regulated hsa-miR-106a target genes phosphatase and tensin homolog (PTEN) and Bcl-2-like protein 11 (BCL2L11) in podocytes. Conclusion: hsa_circ_0001230 and hsa_circ_0023879 are novel blood biomarkers for FSGS. They may regulate podocyte apoptosis by competitively binding to hsa-miR-106a.