Analysis of the combined effect of rs699 and rs5051 on angiotensinogen expression and hypertension

Abstract

Abstract Background Hypertension (HTN) involves genetic variability in the renin‐angiotensin system and influences antihypertensive response. We previously reported that angiotensinogen (AGT) messenger RNA (mRNA) is endogenously bound by miR‐122‐5p and rs699 A > G decreases reporter mRNA in the microRNA functional‐assay PASSPORT‐seq. The AGT promoter variant rs5051 C > T is in linkage disequilibrium (LD) with rs699 A > G and increases AGT transcription. The independent effect of these variants is understudied due to their LD therefore we aimed to test the hypothesis that increased AGT by rs5051 C > T counterbalances AGT decreased by rs699 A > G, and when these variants occur independently, it translates to HTN‐related phenotypes. Methods We used in silico, in vitro, in vivo, and retrospective models to test this hypothesis. Results In silico, rs699 A > G is predicted to increase miR‐122‐5p binding affinity by 3%. Mir‐eCLIP results show rs699 is 40–45 nucleotides from the strongest microRNA‐binding site in the AGT mRNA. Unexpectedly, rs699 A > G increases AGT mRNA in an AGT‐plasmid‐cDNA HepG2 expression model. Genotype‐Tissue Expression (GTEx) and UK Biobank analyses demonstrate liver AGT expression and HTN phenotypes are not different when rs699 A > G occurs independently from rs5051 C > T. However, GTEx and the in vitro experiments suggest rs699 A > G confers cell‐type‐specific effects on AGT mRNA abundance, and suggest paracrine renal renin‐angiotensin‐system perturbations could mediate the rs699 A > G associations with HTN. Conclusions We found that rs5051 C > T and rs699 A > G significantly associate with systolic blood pressure in Black participants in the UK Biobank, demonstrating a fourfold larger effect than in White participants. Further studies are warranted to determine if altered antihypertensive response in Black individuals might be due to rs5051 C > T or rs699 A > G. Studies like this will help clinicians move beyond the use of race as a surrogate for genotype.

Keywords

• angiotensinogen
• genetic and genomic medicine
• hypertension
• rs699