Abstract 001: Germline Mutagenesis Induces Blood Pressure And Heart Rate Variation In Mice Uncovering Novel Insights On The Genesis Of Cardiovascular Disease Risks

Resting blood pressure (BP) and heart rate (HR) levels are independent risk factors for cardiovascular diseases and mortality. Both phenotypes are critical for lifetime maintenance of the cardiovascular homeostasis and are under the influence of multiple factors. The estimated heritability for both phenotypes is high, but their main genetic determinants remain elusive. To address this shortcoming, we used a strategy to systematically identify genes affecting BP and HR regulation through high-throughput N-ethyl-N-Nitrosurea-induced germline mutagenesis. First, the random chemical-induced mutations were identified in founder animals by whole exome G1 progenitor sequencing and their zygosity established in G2/G3 mice before phenotypic assessment. We used the noninvasive tail cuff method to assess BP and HR in conscious G3 mice distributed in pedigrees of 30-100 G1 descendants. The quantitative traits were then analyzed with Linkage Analyzer in single or multiple combined pedigrees, detecting significant linkage between individual mutations and altered phenotypic scores in heterozygous or homozygous mice. Here, we report the initial results of BP and HR candidate genes selected during the screening of 45,261 G3 mice from 878 pedigrees, testing the effects of 45,317 variant alleles within 14,575 genes, in which 23 % of all autosomal genes were severely damaged. The data indicate that ENU mutagenesis effectively identified 85 candidate genes affecting BP and 132 HR levels, including only 13 and 18 genes previously known to influence BP and HR, respectively. Moreover, we validated the influence of three and seven new genes on BP and HR control through reverse genetics that may be associated with ageing, vascular integrity and cardiac development. These findings shed light on novel underlying mechanisms associated with both phenotypes and highlight sub-systems contributing to the genesis of critical risk factors associated with cardiovascular diseases.