title: Deletion of RBP-J in adult mice leads to the onset of aortic valve degenerative diseases.
abstract: Transcription factor RBP-J-mediated Notch signaling has been implicated in several inherited cardiovascular diseases including aortic valve diseases (AVD). But whether Notch signal plays a role in AVD in adults has been unclear. This study aims to test whether the deletion of RBP-J in adult mice would lead to AVD and to investigate the underlying mechanisms. Cre-LoxP-mediated gene deletion was employed to disrupt Notch signal in adult mice. Immunofluorescence and electron microscope observations showed that deletion of RBP-J in adult mice led to early morphological changes of AVD. The size of aortic valve was enlarged. The endothelial homeostasis was perturbed, probably due to the up-regulation of VEGFR2. The endothelial cells exhibited increased proliferation and loose endothelial junctions. The valvular mesenchyme displayed significant fibrosis, consistent with the up-regulation of TGF-β1 and activation of endothelial-mesenchymal transition. We observed melanin-producing cells in aortic valves. The number of melanin-producing cells increased significantly, and their location changed from the mesenchyme to subendothelial layer of valve cusps in RBP-J deficient mice. These results suggest that RBP-J-mediated Notch signaling in aortic valves may be critically involved in valve homeostasis and valve diseases as well. These findings will be helpful for the understanding of the molecular mechanisms of AVD in adults.
authors.affiliation: Department of Cardiovascular Surgery, Xijing Hospital, Fourth Military Medical University, Chang-Le Xi Street #17, Xian, 710032, China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Li
authors.forename: Lei
authors.initials: L
authors.lastname: Feng
authors.forename: Chun-Mei
authors.initials: CM
authors.lastname: Wang
authors.forename: Qi-Jun
authors.initials: QJ
authors.lastname: Zheng
authors.forename: Bi-Jun
authors.initials: BJ
authors.lastname: Zhao
authors.forename: Wei
authors.initials: W
authors.lastname: Yi
authors.forename: Jin-Zhou
authors.initials: JZ
authors.lastname: Zhang
authors.forename: Yue-Min
authors.initials: YM
authors.lastname: Wang
authors.forename: Hai-Tao
authors.initials: HT
authors.lastname: Guo
authors.forename: Ding-Hua
authors.initials: DH
authors.lastname: Yi
authors.forename: Hua
authors.initials: H
authors.lastname: Han
mesh_terms: D000375:Aging / Q000473:pathology*; D000818:Animals; D001021:Aortic Valve / Q000002:abnormalities / Q000473:pathology* / Q000648:ultrastructure; D006332:Cardiomegaly / Q000150:complications / Q000473:pathology; D049109:Cell Proliferation; D004727:Endothelium / Q000473:pathology; D017353:Gene Deletion; D006349:Heart Valve Diseases / Q000150:complications / Q000473:pathology*; D051819:Immunoglobulin J Recombination Signal Sequence-Binding Protein / Q000172:deficiency* / Q000378:metabolism; D008543:Melanins / Q000378:metabolism; D008648:Mesoderm / Q000473:pathology; D051379:Mice; D018345:Mice, Knockout; D015854:Up-Regulation; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism
chemical_list: D051819:Immunoglobulin J Recombination Signal Sequence-Binding Protein; D008543:Melanins; C497571:Rbpj protein, mouse; D040301:Vascular Endothelial Growth Factor Receptor-2