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Zhang M, Urabe G, Little C, Wang B, Kent AM, Huang Y, Kent KC, Guo LW. HDAC6 Regulates the MRTF-A/SRF Axis and Vascular Smooth Muscle Cell Plasticity. JACC Basic Transl Sci 2018; 3:782-795. [PMID: 30623138 PMCID: PMC6314972 DOI: 10.1016/j.jacbts.2018.08.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 07/31/2018] [Accepted: 08/23/2018] [Indexed: 01/04/2023]
Abstract
Distinct from other histone deacetylases, HDAC6 primarily resides in the cytosol. Unexpectedly, HDAC6-selective inhibition (or silencing) enhances the nuclear activity of SRF. HDAC6 inhibition elevates acetylation and protein levels of myocardin-related transcription factor A, a cytoplasmic-nuclear shuttling co-activator of SRF. Myocardin-related transcription factor A/SRF are known to critically regulate vascular smooth muscle cell phenotypic stability. HDAC6 inhibition prevents smooth muscle cell dedifferentiation in vitro and reduces neointima and restenosis in vivo.
Cellular plasticity is fundamental in biology and disease. Vascular smooth muscle cell (SMC) dedifferentiation (loss of contractile proteins) initiates and perpetrates vascular pathologies such as restenosis. Contractile gene expression is governed by the master transcription factor, serum response factor (SRF). Unlike other histone deacetylases, histone deacetylase 6 (HDAC6) primarily resides in the cytosol. Whether HDAC6 regulates SRF nuclear activity was previously unknown in any cell type. This study found that selective inhibition of HDAC6 with tubastatin A preserved the contractile protein (alpha-smooth muscle actin) that was otherwise diminished by platelet-derived growth factor-BB. Tubastatin A also enhanced SRF transcriptional (luciferase) activity, and this effect was confirmed by HDAC6 knockdown. Interestingly, HDAC6 inhibition increased acetylation and total protein of myocardin-related transcription factor A (MRTF-A), a transcription co-activator known to translocate from the cytosol to the nucleus, thereby activating SRF. Consistently, HDAC6 co-immunoprecipitated with MRTF-A. In vivo studies showed that tubastatin A treatment of injured rat carotid arteries mitigated neointimal lesion, which is known to be formed largely by dedifferentiated SMCs. This report is the first to show HDAC6 regulation of the MRTF-A/SRF axis and SMC plasticity, thus opening a new perspective for interventions of vascular pathologies.
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Key Words
- DMEM, Dulbecco’s modified Eagle’s medium
- DNA, deoxyribonucleic acid
- EEL, external elastic lamina
- FBS, fetal bovine serum
- HDAC, histone deacetylase
- HDAC6
- IEL, internal elastic lamina
- IH, intimal hyperplasia
- IgG, immunoglobulin G
- MMP, matrix metalloproteinase
- MRTF-A
- MRTF-A, myocardin-related transcription factor A
- PDGF-BB, platelet-derived growth factor-BB
- SMA, smooth muscle actin
- SMC, vascular smooth muscle cell
- SMHC, smooth muscle myosin heavy chain
- SRF
- SRF, serum response factor
- TNF, tumor necrosis factor
- TSA, trichostatin A
- dedifferentiation
- siRNA, small interfering ribonucleic acid
- vascular smooth muscle cell
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Affiliation(s)
- Mengxue Zhang
- Department of Surgery and Department of Physiology and Cell Biology, College of Medicine, and the Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, Ohio.,Cellular and Molecular Pathology Graduate Program, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
| | - Go Urabe
- Department of Surgery and Department of Physiology and Cell Biology, College of Medicine, and the Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, Ohio.,Department of Surgery, College of Medicine, and the Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, Ohio
| | - Christopher Little
- Department of Surgery, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
| | - Bowen Wang
- Department of Surgery, College of Medicine, and the Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, Ohio
| | - Alycia M Kent
- Department of Surgery, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
| | - Yitao Huang
- Department of Surgery and Department of Physiology and Cell Biology, College of Medicine, and the Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, Ohio
| | - K Craig Kent
- Department of Surgery, College of Medicine, and the Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, Ohio
| | - Lian-Wang Guo
- Department of Surgery and Department of Physiology and Cell Biology, College of Medicine, and the Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, Ohio
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Wang B, Zhang M, Takayama T, Shi X, Roenneburg DA, Kent KC, Guo LW. BET Bromodomain Blockade Mitigates Intimal Hyperplasia in Rat Carotid Arteries. EBioMedicine 2015; 2:1650-61. [PMID: 26870791 PMCID: PMC4740308 DOI: 10.1016/j.ebiom.2015.09.045] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 09/24/2015] [Accepted: 09/25/2015] [Indexed: 01/13/2023] Open
Abstract
Background Intimal hyperplasia is a common cause of many vasculopathies. There has been a recent surge of interest in the bromo and extra-terminal (BET) epigenetic “readers” including BRD4 since the serendipitous discovery of JQ1(+), an inhibitor specific to the seemingly undruggable BET bromodomains. The role of the BET family in the development of intimal hyperplasia is not known. Methods We investigated the effect of BET inhibition on intimal hyperplasia using a rat balloon angioplasty model. Results While BRD4 was dramatically up-regulated in the rat and human hyperplastic neointima, blocking BET bromodomains with JQ1(+) diminished neointima in rats. Knocking down BRD4 with siRNA, or treatment with JQ1(+) but not the inactive enantiomer JQ1(−), abrogated platelet-derived growth factor (PDGF-BB)-stimulated proliferation and migration of primary rat aortic smooth muscle cells. This inhibitory effect of JQ1(+) was reproducible in primary human aortic smooth muscle cells. In human aortic endothelial cells, JQ1(+) prevented cytokine-induced apoptosis and impairment of cell migration. Furthermore, either BRD4 siRNA or JQ1(+) but not JQ1(−), substantially down-regulated PDGF receptor-α which, in JQ1(+)-treated arteries versus vehicle control, was also reduced. Conclusions Blocking BET bromodomains mitigates neointima formation, suggesting an epigenetic approach for effective prevention of intimal hyperplasia and associated vascular diseases. Blocking BET epigenetic readers with JQ1(+) mitigates neointimal proliferation in balloon-injured rat carotid arteries. JQ1(+) or BRD4 knockdown inhibits vascular smooth muscle cell proliferation, migration, and PDGF receptor expression. JQ1(+) prevents inflammatory dysfunction of vascular endothelial cells.
The transition of vascular smooth muscle cells to a migratory proliferative state produces a new thick layer of tissue on the inner vessel wall obstructing blood flow. Epigenetic control of this transition is poorly understood. We find that inhibiting a family of epigenetic regulators called “readers” halts this disease-prone process. Our study may open fresh opportunities for epigenetic interventions to prevent smooth muscle cell instability and associated occlusive vascular diseases that pose a great threat to public health.
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Affiliation(s)
- Bowen Wang
- Department of Surgery, Wisconsin Institute for Medical Research, Madison, WI 53705, USA
| | - Mengxue Zhang
- Department of Surgery, Wisconsin Institute for Medical Research, Madison, WI 53705, USA
| | - Toshio Takayama
- Department of Surgery, Wisconsin Institute for Medical Research, Madison, WI 53705, USA; University of Wisconsin Hospital and Clinics, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - Xudong Shi
- Department of Surgery, Wisconsin Institute for Medical Research, Madison, WI 53705, USA
| | - Drew Alan Roenneburg
- Department of Surgery, Wisconsin Institute for Medical Research, Madison, WI 53705, USA
| | - K Craig Kent
- Department of Surgery, Wisconsin Institute for Medical Research, Madison, WI 53705, USA; University of Wisconsin Hospital and Clinics, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - Lian-Wang Guo
- Department of Surgery, Wisconsin Institute for Medical Research, Madison, WI 53705, USA
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