Cell interactions with collagen matrices in vivo and in vitro depend on phosphatidylinositol 3-kinase and free cytoplasmic calcium.
We have investigated the role of phosphatidylinositol 3-kinase (PI3-kinase) in cellular interactions with collagenous matrices. Platelet-derived growth factor-BB (PDGF-BB) elicited a mobilization of intracellular Ca2+ in pig aortic endothelial (PAE) cells transfected with wild type PDGF beta-receptor. This response was greatly reduced in PAE cells transfected with PDGF beta-receptors mutated at positions Y740 and Y751 to prevent PI3-kinase binding. The experimental drug 1D-myo-inositol 1,2,6-trisphosphate (alpha-trinositol) induced a rapid increase and subsequent oscillations of the cytoplasmic Ca2+ concentration in cultured fibroblasts. This response was not due to an effect of alpha-trinositol on inositol 1,4,5-trisphosphate (IP3) receptors. alpha-Trinositol did not influence PDGF-BB elicited chemotaxis through collagen-coated membranes of PAE cells transfected with the wild-type PDGF beta-receptor, but restored PDGF-BB elicited chemotaxis of PAE cells transfected with the PI3-kinase binding-site mutated PDGF beta-receptor. Collagen gel contraction has been suggested to serve as a model for cellular control of interstitial fluid pressure (PIF) in dermis. The PI3-kinase inhibitors wortmannin (50 nM) and LY294002 (5 microM) inhibited the stimulation of fibroblast-mediated collagen gel contraction by 0.4 nM PDGF-BB. Injection of wortmannin in rat paw skin induced a lowering of PIF, and this effect was abolished in animals pre-treated with alpha-trinositol. Pretreatment of rats with alpha-trinositol abolished the decrease in PIF induced by injecting monoclonal anti-rat alpha 2 beta 1 integrin IgG in rat paw skin. Taken together our data indicate that cell-collagen interactions in vivo and in vitro depend on PI3-kinase, and that this dependence can be bypassed by a drug eliciting intracellular Ca2+ mobilization.
Ahlén
K
K
Department of Medical Biochemistry and Microbiology, University of Uppsala, Sweden.
Berg
A
A
Stiger
F
F
Tengholm
A
A
Siegbahn
A
A
Gylfe
E
E
Reed
R K
RK
Rubin
K
K
D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D000911:Antibodies, Monoclonal; D000077214:Becaplermin; D020013:Calcium Signaling / Q000187:drug effects; D002450:Cell Communication; D002478:Cells, Cultured; D002633:Chemotaxis / Q000187:drug effects; D002867:Chromones / Q000494:pharmacology; D003094:Collagen / Q000378:metabolism*; D004730:Endothelium, Vascular; D005109:Extracellular Matrix / Q000378:metabolism*; D005347:Fibroblasts; D015544:Inositol 1,4,5-Trisphosphate / Q000494:pharmacology; D007295:Inositol Phosphates / Q000494:pharmacology*; D019012:Integrin beta1 / Q000276:immunology / Q000502:physiology; D009025:Morpholines / Q000494:pharmacology; D009154:Mutation; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D011312:Pressure; D020574:Proto-Oncogene Proteins c-sis; D051381:Rats; D020797:Receptor, Platelet-Derived Growth Factor beta; D017479:Receptors, Platelet-Derived Growth Factor / Q000235:genetics / Q000378:metabolism; D013552:Swine; D000077191:Wortmannin
D000730:Androstadienes; D000911:Antibodies, Monoclonal; D000077214:Becaplermin; D002867:Chromones; D003094:Collagen; D015544:Inositol 1,4,5-Trisphosphate; D007295:Inositol Phosphates; D019012:Integrin beta1; D009025:Morpholines; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D020797:Receptor, Platelet-Derived Growth Factor beta; D017479:Receptors, Platelet-Derived Growth Factor; D000077191:Wortmannin; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C059368:atrinositol