Comprehensive Druggable Genome-Wide Mendelian Randomization Reveals Therapeutic Targets for Kidney Diseases

Background: Kidney diseases, including membranous nephropathy (MN), IgA nephropathy (IgAN), and chronic kidney disease (CKD), present global health challenges due to their prevalence and severe outcomes. Mendelian randomization (MR) has been used extensively to repurpose drugs and identify novel targets. Thus, our study aims to identify therapeutic targets for kidney diseases, analyze their mechanisms, and assess potential side effects. Methods: Integrated with currently available druggable genes, Summary-data-based Mendelian Randomization (SMR) analysis was conducted to estimate the causal effects of blood expression quantitative trait loci (eQTLs) on kidney diseases. To validate the identified genes, a replication study was performed using distinct blood eQTL and disease genome-wide association study (GWAS) data sources. eQTL data was obtained from eQTLGen and GTEx v8.0, with sample sizes of 31,684 and 15,201, respectively. The data on kidney diseases was sourced from the Kiryluk Lab, CKDgen, and the Finngen consortium, with sample sizes ranging from 7,979 to 412,181. The study population consists of European individuals. Subsequently, two-sample MR and colocalization analysis were employed for further validation. Finally, the potential side effects of the identified key genes in treating kidney diseases were assessed using phenome-wide MR and mediation MR. Results: After correcting for the false discovery rate, a total of 20, 23, and 6 unique potential genes were found to have causal relationships with MN, IgAN, and CKD, respectively. Among them, MN showed validated associations with one gene (HCG18), IgAN demonstrated associations with four genes (AFF3, CYP21A2, DPH3, HLA-DRB5), and chronic kidney disease (CKD) displayed an association with one gene (HLA-DQB1-AS1). Several of these key genes are druggable genes. Further phenome-wide MR analysis revealed that certain genes may be associated with diabetes and fat metabolism, suggesting that these factors could potentially serve as mediators. Conclusion: This study presents genetic evidence that supports the potential therapeutic benefits of targeting these key genes for treating kidney diseases. This is significant for prioritizing drug development efforts for kidney disease treatments.