P4484Notch-dependent endothelial dysfunction in patients with aortic valve calcification

Abstract

Background Aortic valve calcification associated with either bicuspid or tricuspid aortic valve remains among the most dangerous cardiovascular diseases but cellular and molecular reasons of this pathology are not fully understood. It has been shown that NOTCH1 haploinsufficiency in endothelial cells derived from iPS and also inhibition of NOTCH1 in aortic valve endothelial cells gives rise to the activation of proosteogenic pathways. Endothelial cells regulate underlying interstitial cells and govern them to differentiation. Thus, elucidation of molecular mechanisms of endothelial dysfunction could shed light on valve calcification pathogenesis. Purpose To elucidate key genes responsible for valve endothelial dysfunction in aortic valve calcification. Methods Primary human aortic valve endothelial cells (VEC) were isolated from 45 patients (BAV, n=21; TAV, n=26) with calcific aortic valve disease and from 8 healthy donors. Expression of corresponding genes was estimated by qPCR. Results We checked expression of about 30 genes related to Notch/Wnt/Bmp pathways and shear stress response. Endothelial cells of patients with calcification had significantly lower mRNA levels of Notch component genes NOTCH2, NOTCH3, DLL4 and JAG1 as well as of Notch target genes HEY1, SNAIL and SLUG. Expression of Wnt-related genes such as DKK1, GREM1 and TCF4 was altered in VEC from calcified valves. Interestingly, mRNA level of ROBO4, recently suggested to be involved in endothelial dysfunctions, was significantly higher in VEC of patients with calcification. Moreover, endothelium from calcified valves had impaired expression of matrix gla protein (MGP), which is known to sequester calcium and inhibit soft tissue calcification in the vasculature and aortic valve. Conclusions Our data show that Notch pathway genes are downregulated in valve endothelial cells of the patients with aortic valve calcification. Our results suggest also implication of shear stress responsive genes and genes of endothelial performance in changing the properties of valve endothelial population of calcified valves and thus presumably to the pathogenesis of aortic valve calcification. Acknowledgement/Funding Russian Foundation For Basic Research 18-34-00277