The CYP4A/20‐HETE Axis Regulates Ischemia‐induced Neovascularization via Its Actions on Endothelial Progenitor and Preexisting Endothelial Cells

Abstract

20‐hydroxyeicosatetraenoic acid (20‐HETE) was recently identified as a novel contributor of ischemia‐induced neovascularization based on the key observation that pharmacological interferences of the CYP4A/20‐HETE axis decrease ischemic neovascularization. The objective of the present study is to determine whether the underlying cellular mechanisms involve endothelial progenitor cells (EPC) and pre‐existing endothelial cells (EC).We found that ischemia leads to a time‐dependent increase in 20‐HETE that is endothelial in origin using LC/MS/MS analysis and immunofluorescent (IF) microscopy. This is accompanied by increases in SDF‐1a expressions, EPC mobilization from bone marrow, and subsequent homing to ischemic tissues. Pharmacological interferences of the CYP4A/20‐HETE axis with a 20‐HETE synthesis inhibitor Dibromo‐dodecenyl‐methylsulfimide(DDMS) or a 20‐HETE antagonist N‐(20‐hydroxyeicosa‐6(Z), 15(Z)‐dienoyl) glycine(6, 15‐20‐HEDGE) significantly attenuated these increases. Importantly, we also determined that 20‐HETE plays a novel role in maintaining EPC functions and increases in the expression of Oct4, Sox2, and Nanog expression that are indicative of increased progenitor cell stemness. Flow cytometric analysis revealed that pharmacological interferences of the CYP4A/20‐HETE axis decrease the EPC population in culture, whereas 20‐HETE increases the cultured EPC population. Furthermore, ischemia also markedly increased the proliferation, oxidative stress, and ICAM‐1 expression in preexisting EC in the hindlimb gracilis muscles. We found that these increases were markedly negated by DDMS and 6, 15‐20‐HEDGE.Taken together, the CYP4A/20‐HETE axis regulates ischemia‐induced compensatory neovascularization via its combined actions on promoting EPC and local preexisting EC responses that are associated with increased neovascularization.Support or Funding InformationAmerican Heart Association [Grant 11SDG6870004]; National Institutes of Health [Grants HL34300], [Grant DK38226]; Robert A. Welch Foundation [GL625910]This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.