title: Effects of tenascin-C on normal and diabetic retinal endothelial cells in culture.
abstract: OBJECTIVE
  Tenascin-C (TN-C) is expressed in embryogenesis, tissue remodeling, and healing. It is up-regulated in retinas of patients affected by diabetic retinopathy (DR). Because TN-C may promote neovascularization, its potential angiogenic effects were examined in vitro in normal and diabetic retinal endothelial cells (RECs).
  
  
  METHODS
  Bovine and human RECs were cultured on plastic or reconstituted basement membrane (BM) matrix. Production of TN-C, capillary-like tube formation, secondary sprouting, and cell migration, survival, and proliferation were measured with or without angiogenic growth factors (GFs). Antibodies and inhibitors were used to determine the involvement of specific TN-C receptors and signaling pathways.
  
  
  RESULTS
  TN-C significantly delayed collapse of REC capillary-like tubes on BM matrix. It decreased tube involution associated with serum deprivation, high glucose, and exposure to TGF-beta. TN-C's enhancement of tube stability was mediated by alphavbeta3 integrin. TN-C increased REC viability in 0.5% serum and stimulated REC proliferation in 10% serum. It promoted REC secondary sprouting on BM matrix, which involved signaling through mitogen-activated kinase kinase (MEK) and p38 mitogen-activated protein kinase. TN-C also enhanced tube branching after treatment with VEGF and stimulated REC migration twofold. Angiogenic GF increased TN-C production by RECs in an additive manner, which may explain higher levels of TN-C deposition in DR cells.
  
  
  CONCLUSIONS
  TN-C was overexpressed in diabetic and DR REC cultures. TN-C enhanced the sprouting, migratory, and survival effects of angiogenic GFs, and had distinct proliferative, migratory, and protective capacities. The data suggest that TN-C may act as a proangiogenic mediator in DR and other pathologic conditions involving neovascularization.
authors.affiliation: Ophthalmology Research Laboratories, Burns and Allen Research Institute, Cedars-Sinai Medical Center, University of California Los Angeles Medical School Affiliate, Los Angeles, California, USA. castellon@cshs.org
authors.forename: Raquel
authors.initials: R
authors.lastname: Castellon
authors.forename: Sergio
authors.initials: S
authors.lastname: Caballero
authors.forename: Hamdi K
authors.initials: HK
authors.lastname: Hamdi
authors.forename: Shari R
authors.initials: SR
authors.lastname: Atilano
authors.forename: Annette M
authors.initials: AM
authors.lastname: Aoki
authors.forename: Roy W
authors.initials: RW
authors.lastname: Tarnuzzer
authors.forename: M Cristina
authors.initials: MC
authors.lastname: Kenney
authors.forename: Maria B
authors.initials: MB
authors.lastname: Grant
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Ljubimov
mesh_terms: D000293:Adolescent; D000368:Aged; D043925:Angiogenesis Inducing Agents / Q000494:pharmacology; D000818:Animals; D001485:Basement Membrane; D015153:Blotting, Western; D002417:Cattle; D002455:Cell Division / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003930:Diabetic Retinopathy / Q000378:metabolism* / Q000473:pathology; D016228:Endothelial Growth Factors / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D006801:Humans; D008222:Lymphokines / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D011946:Receptors, Antigen / Q000378:metabolism; D015861:Retinal Neovascularization / Q000378:metabolism* / Q000473:pathology; D012171:Retinal Vessels / Q000378:metabolism*; D015398:Signal Transduction; D019063:Tenascin / Q000494:pharmacology / Q000502:physiology*; D016212:Transforming Growth Factor beta / Q000494:pharmacology; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D014945:Wound Healing / Q000187:drug effects
chemical_list: D043925:Angiogenesis Inducing Agents; D016228:Endothelial Growth Factors; D008222:Lymphokines; D011946:Receptors, Antigen; D019063:Tenascin; C028641:Tn receptor; D016212:Transforming Growth Factor beta; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors