title: Fibronectin attenuates increased endothelial monolayer permeability after RGD peptide, anti-alpha 5 beta 1, or TNF-alpha exposure.
abstract: Endothelial permeability can be altered by tumor necrosis factor-alpha (TNF-alpha), a cytokine released in association with inflammation-induced tissue injury. In the subendothelial matrix, fibronectin (Fn) influences endothelial cell adhesion by the interaction of integrins with RGD and non-RGD attachment sites in Fn. We compared the effect of TNF-alpha, RGD-containing peptides (GRGDSP), or antibody to alpha 5 beta 1-integrins on the protein permeability of bovine lung endothelial monolayers as assessed by transendothelial 125I-labeled albumin clearance. We also examined the influence of purified human plasma fibronectin (hFn) on this permeability response. TNF-alpha, RGD peptides, and antibodies to alpha 5 beta 1-integrins elicited a dose- and time-dependent increase in protein permeability as well as a reorganization and/or disruption of the endogenous Fn matrix. A control RGE peptide (GRGESP) as well as immunoglobulin G purified from nonimmune rabbit serum did not increase endothelial protein permeability or disrupt the endogenous fibrillar Fn pattern in the matrix. Likewise, a LDV peptide derived from the alternatively spliced type III connecting segment (IIICS) within bovine Fn (bFn) was unable to increase permeability of the bovine endothelial monolayer. Co-incubation of purified soluble hFn (300 or 600 micrograms/ml) with either TNF-alpha, the RGD peptide, or the antibody to alpha 5 beta 1-integrins prevented the increase in endothelial permeability. This protective effect was also observed when the purified hFn (600 micrograms/ml) was added after the TNF-alpha-induced increase in endothelial permeability had taken place. Immunofluorescent analysis confirmed the incorporation of the hFn into the subendothelial matrix and its co-localization with the endogenous bFn. The similar alteration of the subendothelial matrix after exposure to RGD peptides, anti-alpha 5 beta 1-antibodies, or TNF-alpha, coupled with the ability for hFn to attenuate the permeability increase typically elicited by all three agents, suggests that disruption of cell-matrix interactions may be the mechanism by which TNF-alpha alters endothelial permeability.
authors.affiliation: Department of Physiology and Cell Biology, Albany Medical College, New York 12208, USA.
authors.forename: T M
authors.initials: TM
authors.lastname: Curtis
authors.forename: P J
authors.initials: PJ
authors.lastname: McKeown-Longo
authors.forename: P A
authors.initials: PA
authors.lastname: Vincent
authors.forename: S M
authors.initials: SM
authors.lastname: Homan
authors.forename: E M
authors.initials: EM
authors.lastname: Wheatley
authors.forename: T M
authors.initials: TM
authors.lastname: Saba
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology; D002199:Capillary Permeability / Q000187:drug effects*; D002417:Cattle; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D005353:Fibronectins / Q000494:pharmacology*; D006801:Humans; D016023:Integrins / Q000037:antagonists & inhibitors* / Q000276:immunology; D009842:Oligopeptides / Q000494:pharmacology*; D011651:Pulmonary Artery / Q000166:cytology / Q000378:metabolism; D017469:Receptors, Fibronectin; D012709:Serum Albumin / Q000493:pharmacokinetics; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D000906:Antibodies; D005353:Fibronectins; D016023:Integrins; D009842:Oligopeptides; D017469:Receptors, Fibronectin; D012709:Serum Albumin; D014409:Tumor Necrosis Factor-alpha; C047981:arginyl-glycyl-aspartic acid