Endothelial Scaffolding Protein ENH (Enigma Homolog Protein) Promotes PHLPP2 (Pleckstrin Homology Domain and Leucine-Rich Repeat Protein Phosphatase 2)-Mediated Dephosphorylation of AKT1 and eNOS (Endothelial NO Synthase) Promoting Vascular Remodeling

  • Arterioscler Thromb Vasc Biol. 2020 Jul;40(7):1705-1721. doi: 10.1161/ATVBAHA.120.314172.
Jiaqi Huang   #  1 ,  Changhong Cai   #  2 ,  Tianyu Zheng   #  3 ,  Xinyan Wu  3 ,  Dongfei Wang  4 ,  Kaijie Zhang  1 ,  Bocheng Xu  5 ,  Ruochen Yan  3 ,  Hui Gong  6 ,  Jie Zhang  7 ,  Yueli Shi  3 ,  Zhiyong Xu  3 ,  Xue Zhang  3 ,  Xuemin Zhang  8 ,  Tao Shang  9 ,  Jianhong Zhou  10 ,  Xiaogang Guo  4 ,  Chunlai Zeng  2 ,  En Yin Lai  11 ,  Changchun Xiao  12  13 ,  Ju Chen  14 ,  Shu Wan  15 ,  Wen-Hsien Liu  12 ,  Yuehai Ke  3 ,  Hongqiang Cheng  1  16
Affiliations
  • 1. From the Department of Pathology and Pathophysiology and Department of Cardiology, Sir Run Run Shaw Hospital (J.H., K.Z., H.C.), Zhejiang University School of Medicine, Hangzhou, China.
  • 2. Department of Cardiology, Lishui Hospital, Zhejiang University School of Medicine, China. (C.C., C.Z.).
  • 3. Department of Pathology and Pathophysiology (T.Z., X. Wu, R.Y., Y.S., Z.X., X.Z., Y.K.), Zhejiang University School of Medicine, Hangzhou, China.
  • 4. Department of Cardiovascular Science, The First Affiliated Hospital of Zhejiang University (D.W., X.G.), Zhejiang University School of Medicine, Hangzhou, China.
  • 5. Institute of Feed Science, College of Animal Sciences, Zhejiang University, Hangzhou, China (B.X.).
  • 6. Key Laboratory for Translational Medicine, First Affiliated Hospital, Huzhou University, China (H.G.).
  • 7. Department of Urology, Sir Run Run Shaw Hospital (J. Zhang), Zhejiang University School of Medicine, Hangzhou, China.
  • 8. Department of Vascular Surgery, Peking University People's Hospital, Peking University Health Science Center, Peking University, Beijing, China (X. Zhang).
  • 9. Department of Vascular Surgery, The First Affiliated Hospital (T.S.).
  • 10. Department of Gynecology, School of Medicine, Zhejiang University, Hangzhou, China (J. Zhou).
  • 11. Department of Physiology, School of Basic Medical Sciences (E.Y.L.), Zhejiang University School of Medicine, Hangzhou, China.
  • 12. State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, China (C.X., W.-H.L.).
  • 13. Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA (C.X.).
  • 14. Department of Medicine and Cardiology, University of California San Diego, La Jolla (J.C.).
  • 15. Brain Center of Zhejiang Hospital, Hangzhou, China (S.W.).
  • 16. Key Laboratory of Cardiovascular Intervention and Regenerative Medicine of Zhejiang Province, Hangzhou, China (H.C.).
  • # Contributed equally.
PMID: 32268790 DOI: 10.1161/ATVBAHA.120.314172
Abstract

Objective: A decrease in nitric oxide, leading to vascular smooth muscle cell proliferation, is a common pathological feature of vascular proliferative diseases. Nitric oxide synthesis by eNOS (endothelial nitric oxide synthase) is precisely regulated by protein kinases including Akt1. ENH (enigma homolog protein) is a scaffolding protein for multiple protein kinases, but whether it regulates eNOS activation and vascular remodeling remains unknown. Approach and Results: ENH was upregulated in injured mouse arteries and human atherosclerotic plaques and was associated with coronary artery disease. Neointima formation in carotid arteries, induced by ligation or wire injury, was greatly decreased in endothelium-specific ENH-knockout mice. Vascular ligation reduced Akt and eNOS phosphorylation and nitric oxide production in the endothelium of control but not ENH-knockout mice. ENH was found to interact with Akt1 and its Phosphatase PHLPP2 (pleckstrin homology domain and leucine-rich repeat protein Phosphatase 2). Akt and eNOS activation were prolonged in VEGF (vascular endothelial growth factor)-induced ENH- or PHLPP2-deficient endothelial cells. Inhibitors of either Akt or eNOS effectively restored ligation-induced neointima formation in ENH-knockout mice. Moreover, endothelium-specific PHLPP2-knockout mice displayed reduced ligation-induced neointima formation. Finally, PHLPP2 was increased in the endothelia of human atherosclerotic plaques and blood cells from patients with coronary artery disease.

Conclusions: ENH forms a complex with Akt1 and its Phosphatase PHLPP2 to negatively regulate Akt1 activation in the artery endothelium. Akt1 deactivation, a decrease in nitric oxide generation, and subsequent neointima formation induced by vascular injury are mediated by ENH and PHLPP2. ENH and PHLPP2 are thus new proatherosclerotic factors that could be therapeutically targeted.

Keywords
coronary artery disease; mice; nitric oxide; phosphorylation; vascular remodeling.
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