ANTXR2 Knock-Out Does Not Result in the Development of Hypertension in Rats.

BACKGROUND: Our recent genetic study as well as robust evidences reported by previous genome-wide association studies (GWASs) have indicated that the single nucleotide polymorphism rs16998073, located near gene anthrax toxin receptor 2 (ANTXR2), was significantly associated with hypertension in Asians and Europeans. The aim of the present study was to determine whether ANTXR2 is the causal gene of hypertension at the 4q21 locus using an ANTXR2 knock-out model.

METHODS: Relative expression of ANTXR2 in Wistar-Kyoto rats (WKYs) and spontaneously hypertensive rats (SHRs) were determined by real-time quantitative polymerase chain reaction and western blot analysis. ANTXR2 knock-out rats were created using CRISPR/Cas9-mediated genome editing and blood pressure values were measured in ANTXR2-/- and wild type (WT) rats by tail-cuff method and carotid arterial catheterization method.

RESULTS: Neither the mRNA nor protein levels of ANTXR2 were significantly different between tissues from SHRs and WKYs. To create ANTXR2-/- rats, 67 base pairs were deleted in exon 1 of ANTXR2 using CRISPR/Cas9-mediated genome editing. ANTXR2 protein decreased significantly in aortas of ANTXR2-/- rats, suggesting sufficient efficiency of ANTXR2 knock-out in this model. However, ANTXR2-/- rats exhibited nearly the same blood pressure as WT rats at baseline conditions as well as during Angiotensin II (400ng/kg/min) infusion or high-salt diet treatment.

CONCLUSIONS: These findings suggest that ANTXR2 might not be associated with hypertension and thus further functional analysis is warranted to identify the causal gene at this locus.