Serum-Derived Small Extracellular Vesicles From Diabetic Mice Impair Angiogenic Property of Microvascular Endothelial Cells: Role of EZH2

J Am Heart Assoc. 2021 May 18;10(10):e019755. doi: 10.1161/JAHA.120.019755. Epub 2021 May 14.

Abstract

Background Impaired angiogenic abilities of the microvascular endothelial cell (MVEC) play a crucial role in diabetes mellitus-impaired ischemic tissue repair. However, the underlying mechanisms of diabetes mellitus-impaired MVEC function remain unclear. We studied the role of serum-derived small extracellular vesicles (ssEVs) in diabetes mellitus-impaired MVEC function. Methods and Results ssEVs were isolated from 8-week-old male db/db and db/+ mice by ultracentrifugation and size/number were determined by the Nano-sight tracking system. Diabetic ssEVs significantly impaired tube formation and migration abilities of human MVECs. Furthermore, local transplantation of diabetic ssEVs strikingly reduced blood perfusion and capillary/arteriole density in ischemic hind limb of wildtype C57BL/6J mice. Diabetic ssEVs decreased secretion/expression of several pro-angiogenic factors in human MVECs. Mechanistically, expression of enhancer of zest homolog 2 (EZH2), the major methyltransferase responsible for catalyzing H3K27me3 (a transcription repressive maker), and H3K27me3 was increased in MVECs from db/db mice. Diabetic ssEVs increased EZH2 and H3K27me3 expression/activity in human MVECs. Expression of EZH2 mRNA was increased in diabetic ssEVs. EZH2-specific inhibitor significantly reversed diabetic ssEVs-enhanced expression of EZH2 and H3K27me3, impaired expression of angiogenic factors, and improved blood perfusion and vessel density in ischemic hind limb of C57BL/6J mice. Finally, EZH2 inactivation repressed diabetic ssEVs-induced H3K27me3 expression at promoter of pro-angiogenic genes. Conclusions Diabetic ssEVs impair the angiogenic property of MVECs via, at least partially, transferring EZH2 mRNA to MVECs, thus inducing the epigenetic mechanism involving EZH2-enhanced expression of H3K27me3 and consequent silencing of pro-angiogenic genes. Our findings unravel the cellular mechanism and expand the scope of bloodborne substances that impair MVEC function in diabetes mellitus.

Keywords: angiogenesis; diabetes; enhancer of zest homolog 2; pro‐angiogenic factor; serum‐derived small extracellular vesicles.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Proliferation
  • Cells, Cultured
  • Diabetes Mellitus, Experimental / genetics*
  • Diabetes Mellitus, Experimental / metabolism
  • Diabetes Mellitus, Experimental / pathology
  • Endothelial Cells / metabolism*
  • Endothelial Cells / pathology
  • Enhancer of Zeste Homolog 2 Protein / biosynthesis
  • Enhancer of Zeste Homolog 2 Protein / genetics*
  • Extracellular Vesicles / metabolism*
  • Extracellular Vesicles / pathology
  • Gene Expression Regulation*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Microvessels / metabolism*
  • Microvessels / pathology
  • RNA / genetics*

Substances

  • RNA
  • Enhancer of Zeste Homolog 2 Protein
  • Ezh2 protein, mouse