beta1-integrin-ligand disengagement induces in vitro capillary tube disruption mediated by p38 MAPK activity.
BACKGROUND
Disrupting cell-matrix interactions may lead to capillary injury as seen in sepsis and transplant rejection. Previously, we demonstrated capillary disruption mediated by beta1-integrin-ligand disengagement. We now determine whether p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK) pathways are involved in this capillary injury.


METHODS
Endothelial capillaries on Matrigel were preincubated with a p38 MAPK inhibitor (SB203580), ERK pathway inhibitor (PD98059), or dimethyl sulfoxide. Subsequently, a beta1-integrin blocking (P5D2) or an irrelevant antibody was added. After 24 hours, capillary integrity was quantified as capillary intersections/well. Antibody-treated cell lysates then were immunoprecipitated with either a phospho-p38 MAPK or phospho-ERK1/2 antibody. Kinase activity was measured with ATF-2 and Elk-1 fusion proteins as substrates for p38 MAPK and ERK, respectively, followed by Western blotting.


RESULTS
P5D2 disrupted capillary tubes. Increased p38 MAPK activity at 8 hours and ERK activity at 2 and 8 hours were seen in P5D2-treated lysates. Preincubation with SB203580, but not with PD98059 or DSMO, significantly reduced capillary tube disruption.


CONCLUSIONS
The beta1-integrin-ligand disengagement resulted in capillary disruption and stimulated p38 MAPK and ERK activity. In spite of activation of both pathways, the p38 MAPK but not the ERK pathway inhibitor prevented beta1-integrin antibody effects. Inhibiting p38 MAPK may mitigate capillary injury associated with sepsis and transplant rejection.
Da Silva
Monica S
MS
Department of Surgery, SUNY Upstate Medical University, Syracuse, NY 13210, USA.
Siddiqui
Josephine
J
Halverson
Anne
A
Wilasrusmee
Chumpon
C
Bruch
David
D
Kittur
Dilip S
DS
D000906:Antibodies / Q000494:pharmacology; D001011:Aorta; D002196:Capillaries / Q000378:metabolism* / Q000648:ultrastructure*; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000378:metabolism* / Q000648:ultrastructure*; D004789:Enzyme Activation / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D019012:Integrin beta1 / Q000276:immunology / Q000378:metabolism*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases
D000906:Antibodies; D004791:Enzyme Inhibitors; D007093:Imidazoles; D019012:Integrin beta1; D011725:Pyridines; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C093642:SB 203580