Endotoxin-neutralizing protein protects against endotoxin-induced endothelial barrier dysfunction.
Bacterial lipopolysaccharide induces tyrosine phosphorylation of paxillin, actin reorganization, and opening of the transendothelial paracellular pathway through which macromoles flux. In this study, lipid A was shown to be the bioactive portion of the lipopolysaccharide molecule responsible for changes in endothelial barrier function. We then studied whether endotoxin-neutralizing protein, a recombinant peptide that is derived from Limulus antilipopolysaccharide factor and targets lipid A, could block the effects of lipopolysaccharide on protein tyrosine phosphorylation, actin organization, and movement of 14C-bovine serum albumin across bovine pulmonary artery endothelial cell monolayers. In the presence of serum, a 6-h exposure to lipopolysaccharide (10 ng/ml) increased transendothelial 14C-albumin flux compared to the simultaneous media control. Coadministration of endotoxin-neutralizing protein (> or =10 ng/ml) with lipopolysaccharide (10 ng/ml) protected against lipopolysaccharide-induced barrier dysfunction. This protection was dose dependent, conferring total protection at endotoxin-neutralizing protein/lipopolysaccharide ratios of > or =10:1. Similarly, endotoxin-neutralizing protein was capable of blocking the lipopolysaccharide-induced endothelial cell responses that are prerequisite to barrier dysfunction, including tyrosine phosphorylation of paxillin and actin depolymerization. Finally, endotoxin-neutralizing protein cross-protected against lipopolysaccharide derived from diverse gram-negative bacteria. Thus, endotoxin-neutralizing protein offers a novel therapeutic intervention for the vascular endothelial dysfunction of gram-negative sepsis and its attendant endotoxemia.
Bannerman
D D
DD
Department of Pathology, VA Maryland Health Care System, University of Maryland School of Medicine, Baltimore 21201, USA.
Fitzpatrick
M J
MJ
Anderson
D Y
DY
Bhattacharjee
A K
AK
Novitsky
T J
TJ
Hasday
J D
JD
Cross
A S
AS
Goldblum
S E
SE
D000199:Actins / Q000378:metabolism; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides; D060829:Arthropod Proteins; D002417:Cattle; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000378:metabolism; D007447:Invertebrate Hormones / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors / Q000633:toxicity*; D010766:Phosphorylation; D012710:Serum Albumin, Bovine / Q000378:metabolism; D013329:Structure-Activity Relationship; D014443:Tyrosine / Q000378:metabolism
D000199:Actins; D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D060829:Arthropod Proteins; D007447:Invertebrate Hormones; D008070:Lipopolysaccharides; C034705:antilipopolysaccharide factor (Limulus); D012710:Serum Albumin, Bovine; D014443:Tyrosine