Deletion of Kcnj16 altered transcriptomic and metabolomic profiles of Dahl salt-sensitive rats

Abstract

The essential role of inwardly rectifying K+ Channel Kir5.1 (encoded by the Kcnj16 gene) in renal salt handling and blood pressure control has been demonstrated in both human and animal models. However, the underlying mechanisms are still not fully understood. Here, we aimed to integrate transcriptomics and metabolomics to profile the comprehensive changes of genes and metabolites under the deletion of Kcnj16 in the Dahl salt-sensitive (SS) rat background to identify novel mechanisms. For the transcriptomics profiling, we performed RNA-sequencing on kidney cortex tissue of Kcnj16 knockout (KO) and wild-type (WT) SS rats (N=5 per group). For the metabolomics profiling, we performed untargeted metabolomics of kidney cortex tissue, plasma, and urine of KO (N=6) and WT (N=5) rats. Transcriptomics analysis revealed over 6,000 differentially expressed genes in KO rats compared to WT rats, with renin Ren (the gene encoding renin) being the most upregulated gene. Consistent with the phenotype observed in the KO rats, ingenuity pathway analysis (IPA) based on the transcriptomic profile predicted reduced blood pressure and kidney damage and increased ion transport. Canonical pathway analysis suggested activation of metabolic-related pathways [e.g., xenobiotic metabolism, tricarboxylic acid (TCA) cycle, phenylalanine degradation, etc.] and suppression of immune responses-related pathways [e.g., pathogen-induced cytokine storm signaling pathway, macrophage classical activation signaling pathway, nuclear factor of activated T cells (NFAT) pathway, etc.] in KO rats. Untargeted metabolomic analysis suggested distinct metabolic profiles of plasma, urine, and kidneys between WT and KO rats, with 219, 790, and 31 differentially expressed metabolites identified in plasma, urine, and kidney in KO rats compared to WT rats. Canonical pathway analysis identified spermine and spermidine degradation pathways in both plasma and urine and taurine biosynthesis pathways in both urine and kidney. Integration analysis based on transcriptomic and metabolomic profiles suggested an altered TCA cycle, amino acid, and reactive oxygen species metabolism. In conclusion, besides significantly altered ion transport, our transcriptomics and metabolomics data suggest significant suppressed immune responses-related and altered metabolic-related pathways in SS rats lacking Kir5.1, which provides new insights into the underlying mechanisms of the regulation of blood pressure and renal function by Kir5.1. This work is supported by National Institutes of Health Grants R35 HL135749 and R01 DK135644 (to A.S.), Department of Veteran Affairs grant I01 BX004024 (to A.S.), the American Physiological Society Postdoctoral Fellowship (to B.X.) and the American Society of Nephrology Dimitrios G. Oreopoulos Research Fellowship Award (to L.V.D.). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.