Disruption of Notch1 and Gata5 in mice leads to congenital aortic valve disease

Congenital aortic valve disease (AVD) is one of the most common type of congenital heart defects whose molecular and genetic basis is poorly understood. Pathogenic variants in NOTCH1 and GATA5 have been associated with AVD including aortic valve stenosis (AVS) and bicuspid aortic valve (BAV). Whereas previous genetic mouse models of AVD with Notch1 haploinsufficiency or Gata5 deletion alone display limitations with regards to significant perinatal lethality or a partially penetrance, and here, we generate a new murine model by intercrossing Notch1 and Gata5 heterozygote mice. We demonstrate that Notch1;Gata5 compound mutant mice display highly penetrant and clinically relevant congenital AVS without early lethality. Echocardiographic examination shows progressive AVS and aortic dilatation in Notch1+/-;Gata5-/- compound mutant mice at 6 and 16 weeks of age. Histologic analysis of 16 week old Notch1;Gata5 compound mutant mouse hearts identifies myxomatous aortic valves with thickened and dysmorphic leaflets. Morphologic analysis reveals the presence of BAV in a subset of Notch1;Gata5 compound mice. Furthermore, histologic analysis demonstrates AVS and aortic valve leaflet thickening with proteoglycan accumulation at embryonic day 18.5 and postnatal day 10, consistent with congenital disease. RNA-sequencing analysis of postnatal day 10 aortic valves demonstrates dysregulation of extracellular matrix (ECM) genes in Notch1+/-;Gata5-/- compound mutant mice. In conclusion, we demonstrate a novel genetic interaction between Notch1 and Gata5, which is critical for the proper aortic valve development, and show that Notch1+/-;Gata5-/- compound mutant mice represent a novel mouse model of congenital and progressive AVS.