title: Inhibition of elastin peptide-mediated angiogenic signaling mechanism(s) in choroidal endothelial cells by the α6(IV)NC1 collagen fragment.
abstract: OBJECTIVE
  The inhibitory effects and mechanism(s) of type IV collagen α-6 chain-derived noncollagenous domain (α6[IV]NC1 or hexastatin) on elastin-derived peptide (EDP)-activated choroidal endothelial cell migration, kinase signaling, and membrane type 1 metalloproteinase (MT1-MMP) activation are explored.
  
  
  METHODS
  Mouse choroidal endothelial cells (MCECs) were incubated in media with soluble EDPs (kappa elastin, mouse elastin, and Val-Gly-Val-Ala-Pro-Gly [VGVAPG] hexapeptide) for different time intervals with or without α6(IV)NC1. The MCECs proliferation, migration, tube formation, MT1-MMP expression, and angiogenic signaling were analyzed in cells subjected to EDP and α6(IV)NC1 treatments. The MCECs also were subjected to EDPs, and specific inhibitors for evaluation of focal adhesion kinase (FAK) and protein kinase B (Akt) phosphorylation.
  
  
  RESULTS
  Kappa elastin, mouse elastin, and VGVAPG enhanced the migration, without affecting the proliferation of MCECs. The α6(IV)NC1 inhibited survival and EDP-activated migration of MCECs. The EDP-activated MCEC tube formation on matrigel also was inhibited by α6(IV)NC1. Further, EDP-activated MT1-MMP expression and FAK/phosphoinositide-3-kinase (PI-3K)/mammalian target of rapamycin (mToR)/Akt phosphorylation in MCECs, were reduced by α6(IV)NC1. The EDP-induced FAK and Akt phosphorylation was blocked by FAK- and Akt-specific inhibitors.
  
  
  CONCLUSIONS
  The EDPs and α6(IV)NC1 are identified to exhibit opposing effects on MCEC angiogenic behavior and signaling. The α6(IV)NC1 inhibited cell survival, EDP-mediated migration, MT1-MMP expression and, FAK/PI-3K/mToR/Akt phosphorylation in MCECs. This work demonstrates α6(IV)NC1 as a prospective endogenous molecule for the treatment of diseases involving choroidal neovascularization in the eye.
authors.affiliation: Cell Signaling, Retinal & Tumor Angiogenesis Laboratory, Boys Town National Research Hospital, Omaha, Nebraska.
authors.forename: Venugopal
authors.initials: V
authors.lastname: Gunda
authors.forename: Raj Kumar
authors.initials: RK
authors.lastname: Verma
authors.forename: Yakkanti Akul
authors.initials: YA
authors.lastname: Sudhakar
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002465:Cell Movement / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002829:Choroid / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D020256:Choroidal Neovascularization / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D024141:Collagen Type IV / Q000494:pharmacology*; D004549:Elastin / Q000378:metabolism*; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D011446:Prospective Studies; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D024141:Collagen Type IV; D004549:Elastin
keywords: angiogenesis; elastin-derived peptides; noncollagenous domains of type IV collagen