Abstract Body: Introduction: Hypertension (HTN) remains poorly controlled at the population level. The kidney plays a prominent role in HTN, but the molecular mechanisms are unclear. We enrolled a cohort of patients with HTN, and controls, to study new molecular signatures in the transcriptome of cells shed in first morning urine samples.
Methods: We collected demographics, 24-h and first-morning urine collections from 80 non-diabetic patients aged >40 with HTN and 20 controls (no HTN). Descriptive variables were summarized. Gene expression was assessed after Next Gen sequencing of mRNA obtained from cells pulled down from first-morning urine and assessed for differentially expressed genes (DEG) (<1 Log2 fold-, p<0.05 FDR) by the Wilcoxon Rank-Sum test. Pathway analysis for DEGs was performed with an in-house Python script that highlights genes associated with cardiovascular diseases including HTN, CKD, type 2 diabetes, inflammation, surface proteins (GPCR, transporters, etc), and the kinome.
Results: Cohort characteristics are shown in Table 1. After QC, full transcriptomes were analyzed for 11 control and 34 HTN subjects. 20,800 transcripts were identified (including known genes, ORFs and LncRNAs) and compared between groups. 916 DEGs (FDR p<0.05) were identified: 911 genes up- and 5 down-regulated. In HTN subjects, there was overrepresentation of genes in inflammatory signaling pathways (12.5% of all DEGs) including those in IFN-alpha, IFN-gamma, Interleukin (IL)9, IL17 and IL18, and innate immunity. 15 genes, associated with HTN, and 45, associated with type-2 diabetes, at the genome-wide level were up-regulated in the HTN cohort including (LINC00592, ADRA1D, SLC39A12, WNT3A, RXFP2, DEFB136, PDE3A, OPRM1, RIBC2, GRIN2A, CHEK2, HOXA3, CCDC149, COL4A2). Transcripts for major apical nephron NaCl transporters were not significantly different, however, SLC12A5 (K/Cl cotransporter KCC2) and the voltage gated K channels (KCNE1, KCNE2) were up-regulated in HTN patients.
Conclusions: We conclude that analysis of transcriptomes of cells shed in first morning urine of control and HTN patients allows for the identification of DEG. These data align well with our previous finding indicating that renal inflammation is associated with difficult-to-control hypertension, and as shown here, are also associated with HTN in general. This method allows for discovery of new inflammatory pathways that could render additional treatments for HTN or CKD.