MicroRNAs as a therapeutic target in IgA nephropathy in Indian population.

Immunoglobulin A nephropathy (IgAN) is the most frequent glomerular disease with rapid development to end stage renal disease, requiring renal replacement therapy. Genome-wide studies suggest geographical variations in genetic susceptibility to IgAN and disease progression. Specific 'candidate genes' were indicated to correlate with different functions that are involved in the pathogenesis of renal conditions. MicroRNAs (miRNAs/miRs) have a major role in mRNA degradation or translation repression, thereby regulating the expression of their target proteins. Previously, a small number of miRNAs were reported to have direct associations with IgAN. In the present study, new miRNAs linked to IgAN were identified in the Indian population. The miRNA was isolated from kidney biopsies of patients with IgAN (n=6) and healthy control tissue from patients with renal cell carcinoma (n=6). The sequencing results indicated that the miRNA percentage acquired from controls and patients with IgAN was 5.61 and 4.35%, respectively. From the results, 10 upregulated and 15 downregulated miRNAs were identified. Of the 25 differentially expressed miRNAs (DEMs), miR-181a-5p, miR-28-3p, let-7g-5p, miR-92a-3p and miR-30c-5p were not reported previously. Furthermore, Kyoto Encyclopedia of Genes and Genomes and Gene Ontology analyses suggested that the target genes of the DEMs were mainly enriched in pathways such as cancer, ErbB signalling, proteoglycans in cancer, Hippo signalling and MAPK pathways. The newly identified miRNAs may impact the behaviour of tissues or IgA deposition by regulating signalling pathways, which forms a basis for future studies aimed at improving the diagnosis and care of patients with IgAN in the Indian community.

Whole-Exome Sequencing Identifies a Variant in Phosphatidylethanolamine N-Methyltransferase Gene to be Associated With Lean-Nonalcoholic Fatty Liver Disease.

BACKGROUND AND AIM: Nonalcoholic fatty liver disease (NAFLD) is a spectrum of liver diseases with simple steatosis on one end and hepatocellular carcinoma on the other. Although obesity is a known risk factor for NAFLD, individuals with normal body mass index (BMI) also have hepatic fatty infiltration, now termed "lean-NAFLD". It represents a distinct entity with a strong underlying genetic component. The present study aimed to sequence the complete exonic regions of individuals with lean-NAFLD to identify germline causative variants associated with disrupted hepatic fatty acid metabolism, thereby conferring susceptibility to NAFLD. METHODS: Whole blood was collected from patients with lean-NAFLD (n = 6; BMI < 23.0 kg/m2) and matched lean controls (n = 2; discovery set). Liver fat was assessed using acoustic radiation force impulse (ARFI) imaging. Patients with ultrasound-detected NAFLD (n = 191) and controls (n = 105) were part of validation set. DNA was isolated, and whole-exome sequencing (WES) was performed in the discovery cohort (Ion Proton™; Ion AmpliSeq™ Exome RDY Kit). Data were analyzed (Ion Reporter software; Life Technologies), and variants identified. Validation of variants was carried out (Taqman probes; Real time-PCR). Student's t test and Fisher's exact test were used to analyze the statistical significance. RESULTS: Although WES identified ∼74,000 variants in individual samples, using various pipelines. variants in genes namely phosphatidylethanolamine N-methyltransferase (PEMT) and oxysterol-binding protein-related protein10 (OSBPL10) that have roles in dietary choline intake and regulation of cholesterol homeostasis, respectively, were identified (discovery set). Furthermore, significant differences were noted in BMI (p = 0.006), waist/hip circumference (p > 0.001), waist/hip ratio (p > 0.001), aspartate aminotransferase (p > 0.001), alanine aminotransferase (p > 0.001), and triglycerides (p = 0.002) between patients and controls. Validation of variants (rs7946-PEMT and rs2290532-OSBPL10) revealed that variant in PEMT but not OSBPL10 gene was associated (p = 0.04) with threefold increased risk of NAFLD in lean individuals. CONCLUSION: Our results demonstrate the association of rs7946 with lean-NAFLD. WES may be an effective strategy to identify causative variants underlying lean-NAFLD.