Abstract |
Enhanced interaction between vascular endothelial cells and circulating leukocytes, as a result of transcriptional activation of cell adhesion molecules (CAM), helps establish a proinflammatory milieu contributing to the pathogenesis of chronic hypoxia-induced pulmonary hypertension. The molecular switch that dictates CAM transactivation is not clearly defined. Our goal was to determine the involvement of the transcriptional modulator megakaryocytic leukemia 1 (MKL1), also known as myocardin-related transcription factor A (MRTF-A), in CAM transactivation and the underlying mechanism. We report here that compared with wild-type littermates, MKL1/MRTF-A knockout mice were more resistant to the development of hypoxia-induced pulmonary hypertension when exposed to low oxygen pressure. Notably, CAM induction in knockout mice was significantly attenuated with a concomitant reduction of leukocyte adhesion. In cultured vascular endothelial cells, overexpression of MKL1/MRTF-A enhanced, whereas depletion of MKL1/MRTF-A dampened, hypoxia-induced CAM transactivation. In response to hypoxia, MKL1/MRTF-A formed a complex with NF-κB on the CAM promoters. Of interest, MKL1/MRTF-A was responsible for recruiting a histone H3 lysine 4 methyltransferase complex to the CAM promoters. Finally, endothelial-specific silencing of ASH2 and WDR5, 2 key components of the histone H3 lysine 4 methyltransferase complex, ameliorated hypoxia-induced pulmonary hypertension in mice. In conclusion, our data suggest that MKL1/MRTF-A, by coordinating key epigenetic alterations on CAM promoters, provides a critical link to hypoxia-induced endothelial malfunction and contributes to the pathogenesis of hypoxia-induced pulmonary hypertension.
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Authors | Dewei Chen, Yuyu Yang, Xian Cheng, Fei Fang, Gang Xu, Zhibin Yuan, Jun Xia, Hui Kong, Weiping Xie, Hong Wang, Mingming Fang, Yuqi Gao, Yong Xu |
Journal | Hypertension (Dallas, Tex. : 1979)
(Hypertension)
Vol. 65
Issue 4
Pg. 821-33
(Apr 2015)
ISSN: 1524-4563 [Electronic] United States |
PMID | 25646298
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Copyright | © 2015 American Heart Association, Inc. |
Chemical References |
- Mrtfa protein, mouse
- Trans-Activators
- RNA
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Topics |
- Animals
- Disease Models, Animal
- Endothelium, Vascular
(metabolism, physiopathology)
- Epigenesis, Genetic
- Gene Expression Regulation
- Hypertension, Pulmonary
(etiology, genetics, metabolism)
- Hypoxia
(etiology, genetics, metabolism)
- Leukemia, Megakaryoblastic, Acute
(complications, genetics, metabolism)
- Mice
- Mice, Knockout
- Polymerase Chain Reaction
- Pulmonary Wedge Pressure
- RNA
(genetics)
- Trans-Activators
(biosynthesis, genetics)
- Transcriptional Activation
- Vasodilation
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