RT Journal Article
SR Electronic
T1 Functional promoter polymorphisms govern the differential expression of HMG-CoA Reductase gene in rat models of essential hypertension
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 614669
DO 10.1101/614669
A1 Abrar A. Khan
A1 Poovitha Sundar
A1 Vinayak Gupta
A1 Vikas Arige
A1 S. Santosh Reddy
A1 Madhu Dikshit
A1 Manoj K. Barthwal
A1 Nitish R. Mahapatra
YR 2019
UL http://biorxiv.org/content/early/2019/04/19/614669.abstract
AB 3-Hydroxy-3-methyl glutaryl-coenzyme A reductase (Hmgcr) encoding the rate-limiting enzyme in the cholesterol biosynthesis pathway is a candidate gene for essential hypertension (EH). However, the regulation of Hmgcr in rat models of hypertension (viz. Spontaneously Hypertensive Rats [SHR] and its normotensive control Wistar/Kyoto [WKY] strain) is unknown. Here, we show that Hmgcr transcript and protein levels are diminished in liver tissues of SHR as compared to WKY. Consistently, a number of other rat models of hypertension display diminished cholesterol levels as compared to corresponding control strains. Sequencing of the Hmgcr promoter in SHR/WKY reveals three variations: A-405G, C-62T and a 11 bp insertion (-393_-382insTGCGGTCCTCC) in SHR. Moreover, SHR-Hmgcr promoter displays higher activity than WKY-Hmgcr promoter in various cell lines. Transient transfections of Hmgcr-promoter mutants and in silico analysis suggest altered binding of Runx3 and Srebf1 across A-405G and -393_-382insTGCGGTCCTCC sites. Indeed, chromatin immunoprecipitation assays confirm differential binding of Runx3/Srebf1 to Hmgcr promoter leading to diminished expression of Hmgcr in SHR as compared to WKY under basal/cholesterol-modulated conditions. Taken together, this study provides mechanistic insights for the altered Hmgcr expression in these models of EH, thereby unravelling the links of this gene to hypertension and associated cardiovascular disease states.Hmgcr3-Hydroxy-3-Methyl Glutaryl-Coenzyme A reductase;SHRspontaneously hypertensive Rat;WKYwistar/kyoto; BPH, blood pressure high;BPLblood pressure low;BPNblood pressure normal;MCDmethyl-β-cyclodextrin;ChIPchromatin immunoprecipitation;qPCRquantitative real-time PCR;RIPAradio-immunoprecipitation assay;DMEMDulbecco’s Modified Eagle’s Medium;SREBP-1Sterol-regulatory element-binding protein 1;Runx3runt-related transcription factor 3, PVDF, polyvinylidene difluoride;ERADER-associated protein degradation