LAUSR

Background: Hypertension (HTN) and chronic kidney disease (CKD) are associated with vascular damage characterized by vascular remodeling and stiffening and endothelial dysfunction. miRNAs are small non-coding RNA that regulate gene expression by binding to their target messenger RNAs (mRNAs), leading to mRNA degradation or translational repression. Their implication in vascular injury remains unclear. We aimed to identify differentially expressed (DE) miRs in small arteries of HTN and CKD human subjects to gain insight into pathophysiological molecular mechanisms in these conditions. Methods: Normotensive, HTN [systolic blood pressure (BP) >135 mmHg or diastolic BP of 85-115 mmHg with BpTRU] and CKD subjects (estimated glomerular filtration rate <60mL/min/m 2 ) (n=15-16) were studied. Small arteries were isolated from subcutaneous gluteal biopsies and RNA extracted for small and total RNA sequencing using Illumina HiSeq-2500 and further studied using a systems biology approach. Differentially expressed (DE) genes were identified with fold change >1.5 and fold discovery rate <0.1. Results: DE miRs were identified ( P <0.05) uniquely associated with HTN (3↑ and 6↓) or CKD (42↑ and 39↓) or both groups (2↓). Correlation between RNA-sequencing and RT-qPCR data was demonstrated for 3 of 14 tested miRs. Among them, the first-ranked, miR-338-3p ( r =0.91, P <10 -16 ), uniquely associated with CKD, was studied further. miR-338-3p and some of its predicted targets were highly expressed in human aortic endothelial cells (HAECs). Two of them, alkaline ceramidase 2 ( ACER2 ) and glutathione peroxidase 3 (GPX3), were up-regulated by ~36% and ~60% in HAECs transfected with anti-miR-338-3p, respectively ( P <0.05). miR-338-3p mimic co-transfection decreased by 30% luciferase activity of reporter vectors containing the conserved wild-type but not mutated ACER2 or GPX3 3’ untranslated transcribed region miR-338-3p-5p binding sites ( P <0.05). Conclusion: miR-338-3p was down-regulated in small arteries, which was uniquely associated with CKD. ACER2 and GPX3 , identified as miR-338-3p targets, may play a role in vascular injury in CKD.