title: Endothelial-Specific EphA4 Negatively Regulates Native Pial Collateral Formation and Re-Perfusion following Hindlimb Ischemia.
abstract: Leptomeningeal anastomoses play a critical role in regulating vascular re-perfusion following obstruction, however, the mechanisms regulating their development remains under investingation. Our current findings indicate that EphA4 receptor is a novel negative regulator of collaterogenesis. We demonstrate that EphA4 is highly expressed on pial arteriole collaterals at post-natal day (P) 1 and 7, then significantly reduced by P21. Endothelial cell (EC)-specific loss of EphA4, EphA4f/f/Tie2::Cre (KO), resulted in an increase in the density but not diameter of pial collaterals compared to WT mice. ECs isolated from KO mice displayed a 3-fold increase in proliferation, enhanced migration, tube formation and elevated levels of phospho(p)-Akt compared to WT ECs. Attenuating p-Akt, using LY294002, reduced the proliferative and migration effects in the KO ECs. RNAseq analysis also revealed altered expression patterns for genes that regulate cell proliferation, vascular development, extracellular matrix and immune-mediate responses, namely MCP-1, MMP2 and angiopoietin-1. Lastly, we show that induction of hindlimb ischemia resulted in accelerated re-perfusion, collateral remodeling and reduced tissue necrosis in the absence of EC-specific EphA4 compared to WT mice. These findings demonstrate a novel role for EphA4 in the early development of the pial collateral network and suggests a role in regulating vascular remodeling after obstruction.
authors.affiliation: The Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Insititue and State University, 215 Duck Pond Drive, Blacksburg, Virginia, 24061, United States of America.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Okyere
authors.affiliation: The Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Insititue and State University, 215 Duck Pond Drive, Blacksburg, Virginia, 24061, United States of America.
authors.forename: Kaavya
authors.initials: K
authors.lastname: Giridhar
authors.affiliation: The Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Insititue and State University, 215 Duck Pond Drive, Blacksburg, Virginia, 24061, United States of America.
authors.forename: Amanda
authors.initials: A
authors.lastname: Hazy
authors.affiliation: The Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Insititue and State University, 215 Duck Pond Drive, Blacksburg, Virginia, 24061, United States of America.
authors.forename: Miao
authors.initials: M
authors.lastname: Chen
authors.affiliation: Virginia BioComplexity Institute, Virginia Polytechnic Insititue and State University, 1015 Life Science Circle, Blacksburg, Virginia, 24061, United States of America.
authors.forename: David
authors.initials: D
authors.lastname: Keimig
authors.affiliation: The Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Insititue and State University, 215 Duck Pond Drive, Blacksburg, Virginia, 24061, United States of America.
authors.forename: Robert C
authors.initials: RC
authors.lastname: Bielitz
authors.affiliation: Virginia BioComplexity Institute, Virginia Polytechnic Insititue and State University, 1015 Life Science Circle, Blacksburg, Virginia, 24061, United States of America.
authors.forename: Hehuang
authors.initials: H
authors.lastname: Xie
authors.affiliation: The Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Insititue and State University, 215 Duck Pond Drive, Blacksburg, Virginia, 24061, United States of America.
authors.forename: Jia-Qiang
authors.initials: JQ
authors.lastname: He
authors.affiliation: The Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Insititue and State University, 215 Duck Pond Drive, Blacksburg, Virginia, 24061, United States of America.
authors.forename: William R
authors.initials: WR
authors.lastname: Huckle
authors.affiliation: The Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Insititue and State University, 215 Duck Pond Drive, Blacksburg, Virginia, 24061, United States of America.
authors.forename: Michelle H
authors.initials: MH
authors.lastname: Theus
mesh_terms: D000818:Animals; D002550:Cerebral Veins / Q000503:physiopathology*; D002867:Chromones; D004730:Endothelium, Vascular / Q000473:pathology / Q000503:physiopathology*; D006614:Hindlimb / Q000098:blood supply*; D007511:Ischemia / Q000503:physiopathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009025:Morpholines; D010477:Perfusion; D036122:Receptor, EphA4 / Q000235:genetics / Q000502:physiology*
chemical_list: D002867:Chromones; D009025:Morpholines; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D036122:Receptor, EphA4