Inhibition of DNA Methylation Regulates Guanylyl Cyclase/Natriuretic Peptide Receptor‐A Gene Expression

Abstract

Cardiac hormone atrial natriuretic peptide binds to guanylyl cyclase/natriuretic peptide receptor‐A (GC‐A/NPRA) and produces second messenger cGMP, which plays a pivotal role in maintaining blood pressure and cardiovascular homeostasis. The molecular and epigenetic mechanisms that contribute to the activation of Npr1 (coding for GC‐A/NPRA) gene expression are not well understood. The present study was aimed at understanding the mechanisms involved in DNA methylation inhibitor, 5‐Azacytidine (5‐aza)‐mediated Npr1 (coding for GC‐A/NPRA) gene transcription. The studies were carried out in rat thoracic aortic vascular smooth muscle cells (RTASMC), cultured in Dulbecco's modified Eagle's medium containing 10% fetal bovine serum and treated with 5‐aza for 24 h. The MethPrimer search result showed the presence of three cytosine‐phosphate‐guanine (CpG) islands on the Npr1 full length promoter, namely island 1 (−886 to −752, 134 bp), island 2 (−310 to −58, 152 bp), and island 3 (−514 to +310, 464 bp) from the transcription start site. 5‐azacytidine significantly induced mRNA levels of Npr1 gene by 4‐fold and NPRA protein expression by 3‐fold in RTASMCs in a dose‐dependent manner. Treatment of cells with 5‐aza significantly (p<0.05) attenuated DNA methyltransferase 1 (DNMT1) protein expression in a dose‐dependent manner. However, there was no noticeable change in the DNMT3a and DNMT3b protein levels. There was a significant reduction in the DNMT activity in 5‐aza‐treated RTASMCs compared with vehicle–treated cells as quantified by EpiQuik DNMT activity assay. The present findings provide a novel regulatory mechanism for Npr1 gene transcription, an important player in the control of hypertension and cardiovascular homeostasis.Support or Funding InformationThis work was supported by an Institutional Development Award (IDeA) from the NIGMS and a partial support from Tulane Carol Lavin Bernick grant award.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.