Histone deacetylase 9 promotes endothelial-mesenchymal transition and an unfavorable atherosclerotic plaque phenotype
Laura Lecce, Yang Xu, Bhargavi V’Gangula, Nirupama Chandel, Venu Pothula, Axelle Caudrillier, Maria Paola Santini, Valentina d’Escamard, Delaine K. Ceholski, Przemek A. Gorski, Lijiang Ma, Simon Koplev, Martin Mæng Bjørklund, Johan L.M. Björkegren, Manfred Boehm, Jacob Fog Bentzon, Valentin Fuster, Ha Won Kim, Neal L. Weintraub, Andrew H. Baker, Emily Bernstein, Jason C. Kovacic
Laura Lecce, Yang Xu, Bhargavi V’Gangula, Nirupama Chandel, Venu Pothula, Axelle Caudrillier, Maria Paola Santini, Valentina d’Escamard, Delaine K. Ceholski, Przemek A. Gorski, Lijiang Ma, Simon Koplev, Martin Mæng Bjørklund, Johan L.M. Björkegren, Manfred Boehm, Jacob Fog Bentzon, Valentin Fuster, Ha Won Kim, Neal L. Weintraub, Andrew H. Baker, Emily Bernstein, Jason C. Kovacic
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Research Article Cardiology Vascular biology

Histone deacetylase 9 promotes endothelial-mesenchymal transition and an unfavorable atherosclerotic plaque phenotype

Abstract

Endothelial-mesenchymal transition (EndMT) is associated with various cardiovascular diseases and in particular with atherosclerosis and plaque instability. However, the molecular pathways that govern EndMT are poorly defined. Specifically, the role of epigenetic factors and histone deacetylases (HDACs) in controlling EndMT and the atherosclerotic plaque phenotype remains unclear. Here, we identified histone deacetylation, specifically that mediated by HDAC9 (a class IIa HDAC), as playing an important role in both EndMT and atherosclerosis. Using in vitro models, we found class IIa HDAC inhibition sustained the expression of endothelial proteins and mitigated the increase in mesenchymal proteins, effectively blocking EndMT. Similarly, ex vivo genetic knockout of Hdac9 in endothelial cells prevented EndMT and preserved a more endothelial-like phenotype. In vivo, atherosclerosis-prone mice with endothelial-specific Hdac9 knockout showed reduced EndMT and significantly reduced plaque area. Furthermore, these mice displayed a more favorable plaque phenotype, with reduced plaque lipid content and increased fibrous cap thickness. Together, these findings indicate that HDAC9 contributes to vascular pathology by promoting EndMT. Our study provides evidence for a pathological link among EndMT, HDAC9, and atherosclerosis and suggests that targeting of HDAC9 may be beneficial for plaque stabilization or slowing the progression of atherosclerotic disease.

Authors

Laura Lecce, Yang Xu, Bhargavi V’Gangula, Nirupama Chandel, Venu Pothula, Axelle Caudrillier, Maria Paola Santini, Valentina d’Escamard, Delaine K. Ceholski, Przemek A. Gorski, Lijiang Ma, Simon Koplev, Martin Mæng Bjørklund, Johan L.M. Björkegren, Manfred Boehm, Jacob Fog Bentzon, Valentin Fuster, Ha Won Kim, Neal L. Weintraub, Andrew H. Baker, Emily Bernstein, Jason C. Kovacic

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Figure 6

Endothelial-specific Hdac9 knockout reduces atherosclerosis and enhances plaque stability in vivo.

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Endothelial-specific Hdac9 knockout reduces atherosclerosis and enhances...
All comparisons shown are using Endo-Hdac9KO mice versus littermate controls, and all mice received tamoxifen. (A) Representative images of aorta before embedding into OCT and en face analysis of aortic plaque. (B) Representative images of the aortic root with staining using oil red O, with quantification of total plaque area and plaque lipid content (red stained area as a percentage of total plaque area). (C) Representative images of aortic root sections using Von Kossa stain (black represents calcification), with quantification of calcification. (D) Representative aortic root images stained with Masson’s trichrome with quantification of collagen content, fibrous cap thickness, and presence/nonpresence of necrotic core (blue, collagen; pink, macrophages and cardiac muscle). (E) Representative immunofluorescence staining images in aortic root plaques for TER119- (red, erythrocyte marker) and DAPI-stained nuclei (blue) and quantification. (F) Representative immunofluorescence staining images of aortic root plaques for BrdU- (green), CD31- (red), and DAPI-stained nuclei (blue) in the endothelial and subendothelial layers, and quantification. Scale bars: 100 μm (B–D); 50 μm (E and F). n = 10 controls versus n = 9 Endo-Hdac9KO mice for all panels. *P ≤ 0.05; **P ≤ 0.01. All analyses performed using unpaired Student’s t test except the following, for which Mann-Whitney U test was used: plaque area (B), calcification (C), and both analyses in F. In addition, presence or nonpresence of necrotic core (D) was analyzed using Fisher’s exact test.