title: Diet-induced aortic valve disease in mice haploinsufficient for the Notch pathway effector RBPJK/CSL.
abstract: OBJECTIVE
  Calcific aortic valve disease is similar to atherosclerosis in that both diseases result from chronic inflammation and endothelial dysfunction. Heterozygous NOTCH1 mutations have been associated to calcific aortic disease and a bicuspid aortic valve. We investigated whether mice with genetic inactivation of the Notch signaling pathway are prone to develop valve disease when exposed to a predisposing diet.
  
  
  RESULTS
  Using Doppler echocardiography, histology, immunohistochemistry, quantitative gene expression analysis, and cell culture assays, we examined the effect of a hypercholesterolemic diet supplemented with vitamin D on mice heterozygous for null mutations in the Notch1 receptor or the effector transcription factor gene RBPJk. After 16 weeks on the hyperlipidemic diet, calcific aortic disease was detected in heterozygous RBPJk mice. Analysis of valve leaflets revealed macrophage infiltration, enhanced collagen deposition, proosteogenic protein expression, and calcification. Heterozygous null Notch1 mice displayed milder histopathologic changes and did not develop any significant hemodynamic disturbance. Valvular disease correlated with reduced expression of the Notch target gene Hey1 in valves of RBPJk heterozygous mice fed the hyperlipidemic diet. Consistent with the in vivo data, Notch signaling inhibition in porcine valve interstitial cells led to downregulation of HEY1 transcription, activation of osteogenic markers, and increased calcified nodule formation.
  
  
  CONCLUSIONS
  We show that Notch signaling disruption via RBPJk heterozygous inactivation results in aortic valve disease. Notch1 heterozygous mice do not show functional impairment, suggesting that additional Notch receptors may be involved in aortic valve homeostasis and disease. Our data establish a genetic mouse model of calcific aortic valve disease and may help to identify a patient population with reduced valvular NOTCH signaling at risk for developing this disease.
authors.affiliation: Cardiovascular Developmental Biology Department, Centro Nacional de Investigaciones Cardiovasculares, Instituto de Salud Carlos III, 28029 Madrid, Spain.
authors.forename: Meritxell
authors.initials: M
authors.lastname: Nus
authors.forename: Donal
authors.initials: D
authors.lastname: MacGrogan
authors.forename: Beatriz
authors.initials: B
authors.lastname: Martínez-Poveda
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Benito
authors.forename: Jesús C
authors.initials: JC
authors.lastname: Casanova
authors.forename: Francisco
authors.initials: F
authors.lastname: Fernández-Avilés
authors.forename: Javier
authors.initials: J
authors.lastname: Bermejo
authors.forename: José Luis
authors.initials: JL
authors.lastname: de la Pompa
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001021:Aortic Valve / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D002114:Calcinosis / Q000209:etiology* / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D002791:Cholesterol, Dietary; D004195:Disease Models, Animal; D015150:Echocardiography, Doppler; D005355:Fibrosis; D005786:Gene Expression Regulation; D005838:Genotype; D057895:Haploinsufficiency; D006349:Heart Valve Diseases / Q000209:etiology* / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D006439:Hemodynamics; D006579:Heterozygote; D006937:Hypercholesterolemia / Q000150:complications* / Q000209:etiology / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D051819:Immunoglobulin J Recombination Signal Sequence-Binding Protein / Q000172:deficiency* / Q000235:genetics; D007150:Immunohistochemistry; D051379:Mice; D018345:Mice, Knockout; D010012:Osteogenesis / Q000235:genetics; D010641:Phenotype; D051881:Receptor, Notch1 / Q000172:deficiency* / Q000235:genetics; D015398:Signal Transduction; D013318:Stroke Volume; D013552:Swine; D016276:Ventricular Function; D014807:Vitamin D
chemical_list: D018797:Cell Cycle Proteins; D002791:Cholesterol, Dietary; C120420:Hey1 protein, mouse; D051819:Immunoglobulin J Recombination Signal Sequence-Binding Protein; C497762:Notch1 protein, mouse; C497571:Rbpj protein, mouse; D051881:Receptor, Notch1; D014807:Vitamin D