PROJECT SUMMARY More than 50% of hypertensive patients show an increased blood pressure sensitivity to salt intake.However population-wide reduction of salt intake has proved to be difficult making it ever more important tobetter understand the mechanism of salt-sensitive hypertension and provide a basis for developing newinterventions. The kidney plays a key physiological role in the development of hypertension including salt-sensitive hypertension. Thousands of genes in the genome encode long non-coding RNAs (lncRNAs). lncRNAs can interactwith and influence the function of other RNA or proteins. Few lncRNAs have been studied for their role inhypertension. Unlike most lncRNAs MALAT1 (metastasis associated lung adenocarcinoma transcript 1; Malat1in rodents) is conserved across many species and expressed at high abundance levels in several tissuesincluding the kidney which suggests MALAT1 might be important physiologically. However MALAT1sphysiological and pathophysiological role remains largely unknown. We discovered recently that renal miR-214-3p targets and suppresses endothelial nitric oxide synthase(eNOS) directly which contributes significantly to the development of salt-sensitive hypertension in rat modelsand possibly humans. This was supported by a systematic analysis of human sequence variants and all miRNAprecursors small RNA deep sequencing in human kidney biopsy specimens kidney-specific inhibition of miR-214-3p in Dahl SS rats and a newly generated mutant rat strain. The Dahl SS rat is the model most widely usedto study the molecular mechanism of human salt-sensitive hypertension. We have obtained a large series of preliminary data that suggest MALAT1 might be dysregulated in thekidneys of salt-sensitive humans and SS rats and might influence the development of salt-sensitive hypertensionby regulating the renal miR-214-3p/eNOS pathway. We propose to investigate MALAT1s role in thedevelopment of salt-sensitive hypertension (Aim 1) the role for the renal miR-214-3p/eNOS pathway in the effectof MALAT1 on hypertension (Aim 2) and the underlying molecular interactions (Aim 3). We will achieve theseaims by using analysis of scarcely available human samples combinatorial gene manipulation in animal modelsand new methods including genome editing and RafTOP (rapid freezing with tagged oligonucleotide pullout).RafTOP is a method for identifying the native interactome for a specific RNA that we developed recently.