Notch1 signaling activation alleviates coronary microvascular dysfunction through histone modification of Nrg-1 via the interaction between NICD and GCN5

The Notch signaling pathway is related to endothelial dysfunction in coronary atherosclerosis. Our objective was to explore the role of Notch signaling in coronary microvascular dysfunction (CMD). CMD models were constructed by sodium laurate injection in vivo and homocysteine (Hcy) stimulation in vitro. The binding ability of Notch Intracellular Domain (NICD)/H3K9Ac/GCN5 (General Control Non-derepressible 5) to Neuregulin-1 (Nrg-1) promoter was examined by chromatin immunoprecipitation. Immunofluorescence staining was conducted to detect CD31 positive cells, NICD localization, and co-localization of NICD and GCN5. Flow cytometry and Tunel staining were conducted to identify the apoptosis. Hematoxylin and eosin staining, quantitative real-time PCR, western blot, immunohistochemical staining, co-immunoprecipitation, and double luciferase report analysis were also conducted. Notch signaling pathway-related protein levels were decreased, levels of Nrg-1 and the phosphorylation of ErbB2 and ErbB4 were enhanced in CMD models. Interference with Nrg-1 further increased the apoptosis in Hcy-induced cardiac microvascular endothelial cells (CMECs). Meanwhile, the activation of the Notch signaling pathway increased the levels of Nrg-1 and the phosphorylation of ErbB2 and ErbB4, as well as inhibited the apoptosis induced by Hcy. Furthermore, NICD and histone acetyltransferase enzyme GCN5 could regulate Nrg-1 promoter activity by affecting the expression of acetylation-modified protein H3K9Ac. In addition, NICD also interacted with GCN5. In vivo results also confirmed that the activation of the Notch signal alleviated CMD. Notch signaling pathway regulates Nrg-1 level through synergistic interaction with GCN5, thereby mitigating CMD.