Genome-wide analysis of microRNAs expression profiling in patients with primary IgA nephropathy

The aim of this study was to investigate the differential expression characteristics and the roles of the genome-wide microRNAs (miRNAs) in immunoglobulin A nephropathy (IgAN) kidney tissues. We used Illumina high-throughput sequencing technology to evaluate the miRNAs expression of six biopsy tissues from IgAN and six normal renal cortex specimens from patients with renal cell carcinoma. We observed a total of 85 miRNAs that were differentially expressed in the six IgAN patients, of which 11 miRNAs were up-regulated and 74 miRNAs were down-regulated in patients' tissues compared with control tissues. Additionally, we identified 55 candidate novel miRNAs in our study, which comprised seven candidates who were detected in the IgAN group and 49 candidates who were detected in the control group. Only one candidate (miR-n-9) was expressed in both groups. The bioinformatics showed that the regulated target genes of differentially expressed miRNAs were associated with immune and renal pathological changes. The identification of specific tissue miRNAs in our study not only helped clarify the genetics or immunology mechanisms involved in the pathogenesis of IgAN but also helped explain the pathological changes in the kidney tissues. We hypothesize that some significant miRNAs might potentially serve as novel diagnostic biomarkers in IgAN patients