A polymorphism in intron I of the human angiotensinogen gene (hAGT) affects binding by HNF3 and hAGT expression and increases blood pressure in mice

• Published in: The Journal of biological chemistry 2019-08, Vol.294 (31), p.11829-11839
• Main Authors: Mopidevi, Brahmaraju, Kaw, Meenakshi K., Sivankutty, Indu, Jain, Sudhir, Perla, Sravan Kumar, Kumar, Ashok
• Format: Article
• Language: English
• Subjects: angiotensin; Angiotensinogen - blood; Angiotensinogen - genetics; Angiotensinogen - metabolism; Animals; Binding Sites; Blood Pressure; cardiovascular disease; CCAAT-Enhancer-Binding Protein-beta - metabolism; Chromatin - metabolism; gene expression; Gene Regulation; genetics; Hep G2 Cells; Hepatocyte Nuclear Factor 3-beta - metabolism; Humans; hypertension; Introns; Linkage Disequilibrium; Liver - metabolism; Mice; Mice, Inbred C57BL; Mice, Transgenic; Polymorphism, Single Nucleotide; Protein Binding; Receptors, Glucocorticoid - metabolism; Renin - genetics; renin angiotensin system; RNA, Messenger - metabolism; single-nucleotide polymorphism (SNP); transgenic mice; vasopressor agent
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.RA119.007715

Angiotensinogen (AGT) is the precursor of one of the most potent vasoconstrictors, peptide angiotensin II. Genome-wide association studies have shown that two A/G polymorphisms (rs2493134 and rs2004776), located at +507 and +1164 in intron I of the human AGT (hAGT) gene, are associated with hypertension. Polymorphisms of the AGT gene result in two main haplotypes. Hap-I contains the variants −217A, −6A, +507G, and +1164A and is pro-hypertensive, whereas Hap-II contains the variants −217G, −6G, +507A, and +1164G and does not affect blood pressure. The nucleotide sequence of intron I of the hAGT gene containing the +1164A variant has a stronger homology with the hepatocyte nuclear factor 3 (HNF3)–binding site than +1164G. Here we found that an oligonucleotide containing +1164A binds HNF3β more strongly than +1164G and that Hap-I–containing reporter gene constructs have increased basal and HNF3- and glucocorticoid-induced promoter activity in transiently transfected liver and kidney cells. Using a knock-in approach at the hypoxanthine-guanine phosphoribosyltransferase locus, we generated a transgenic mouse model containing the human renin (hREN) gene and either Hap-I or Hap-II. We show that transgenic animals containing Hap-I have increased blood pressure compared with those containing Hap-II. Moreover, the transcription factors glucocorticoid receptor, CCAAT enhancer–binding protein β, and HNF3β bound more strongly to chromatin obtained from the liver of transgenic animals containing Hap-I than to liver chromatin from Hap-II–containing animals. These findings suggest that, unlike Hap-II variants, Hap-I variants of the hAGT gene have increased transcription rates, resulting in elevated blood pressure.