Glucose-potentiated chemotaxis in human vascular smooth muscle is dependent on cross-talk between the PI3K and MAPK signaling pathways.
Atheroma formation involves the movement of vascular smooth muscle cells (VSMC) into the subendothelial space. The aim of this study was to determine the involvement of PI3K and MAPK pathways and the importance of cross-talk between these pathways, in glucose-potentiated VSMC chemotaxis to serum factors. VSMC chemotaxis occurred in a serum gradient in 25 mmol/L glucose (but not in 5 mmol/L glucose) in association with increased phosphorylation (activation) of Akt and ERK1/2 in PI3K and MAPK pathways, respectively. Inhibitors of these pathways blocked chemotaxis, as did an mTOR inhibitor. VSMC expressed all class IA PI3K isoforms, but microinjection experiments demonstrated that only the p110beta isoform was involved in chemotaxis. ERK1/2 phosphorylation was reduced not only by MAPK pathway inhibitors but also by PI3K and mTOR inhibitors; when PI3K was inhibited, ERK phosphorylation could be induced by microinjected activated Akt, indicating important cross-talk between the PI3K and ERK1/2 pathways. Glucose-potentiated phosphorylation of molecules in the p38 and JNK MAPK pathways inhibited these pathways but did not affect chemotaxis. The statin, mevinolin, blocked chemotaxis through its effects on the MAPK pathway. Mevinolin-inhibited chemotaxis was restored by farnesylpyrophosphate but not by geranylgeranylpyrophosphate; in the absence of mevinolin, inhibition of farnesyltransferase reduced ERK phosphorylation and blocked chemotaxis, indicating a role for the Ras family of GTPases (MAPK pathway) under these conditions. In conclusion, glucose sensitizes VSMC to serum, inducing chemotaxis via pathways involving p110beta-PI3K, Akt, mTOR, and ERK1/2 MAPK. Cross-talk between the PI3K and MAPK pathways is necessary for VSMC chemotaxis under these conditions.
Campbell
Malcolm
M
Department of Clinical Biochemistry and Metabolic Medicine, Queen's University Belfast, Institute of Clinical Science, Royal Victoria Hospital, Grosvenor Road, Belfast, UK.
Allen
William E
WE
Sawyer
Carol
C
Vanhaesebroeck
Bart
B
Trimble
Elisabeth R
ER
D019883:Alkyl and Aryl Transferases / Q000037:antagonists & inhibitors; D000730:Androstadienes / Q000494:pharmacology; D000873:Anthracenes / Q000494:pharmacology; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D002478:Cells, Cultured / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D002633:Chemotaxis / Q000187:drug effects* / Q000502:physiology; D002867:Chromones / Q000494:pharmacology; D058534:Class I Phosphatidylinositol 3-Kinases; D051231:Farnesyltranstransferase; D005419:Flavonoids / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology*; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000502:physiology; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000502:physiology; D008148:Lovastatin / Q000494:pharmacology; D048670:MAP Kinase Kinase 4; D020935:MAP Kinase Signaling System / Q000187:drug effects; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000502:physiology; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000502:physiology; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors / Q000502:physiology; D009025:Morpholines / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000502:physiology; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011106:Polyisoprenyl Phosphates / Q000494:pharmacology; D011494:Protein Kinases / Q000502:physiology; D017346:Protein Serine-Threonine Kinases / Q000502:physiology; D011518:Proto-Oncogene Proteins / Q000502:physiology; D051057:Proto-Oncogene Proteins c-akt; D011725:Pyridines / Q000494:pharmacology; D012717:Sesquiterpenes; D020123:Sirolimus / Q000494:pharmacology; D058570:TOR Serine-Threonine Kinases; D000077191:Wortmannin; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000502:physiology; D018631:ras Proteins / Q000502:physiology
D019883:Alkyl and Aryl Transferases; D000730:Androstadienes; D000873:Anthracenes; D000911:Antibodies, Monoclonal; D002867:Chromones; D058534:Class I Phosphatidylinositol 3-Kinases; D051231:Farnesyltranstransferase; D005419:Flavonoids; D005947:Glucose; D007093:Imidazoles; D007527:Isoenzymes; D048031:JNK Mitogen-Activated Protein Kinases; D008148:Lovastatin; D048670:MAP Kinase Kinase 4; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases; D009025:Morpholines; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011106:Polyisoprenyl Phosphates; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D011725:Pyridines; D012717:Sesquiterpenes; D020123:Sirolimus; D058570:TOR Serine-Threonine Kinases; D000077191:Wortmannin; D048051:p38 Mitogen-Activated Protein Kinases; D018631:ras Proteins; C432165:pyrazolanthrone; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C004808:farnesyl pyrophosphate; C546842:MTOR protein, human; C497132:PIK3CB protein, human; C494918:AKT1 protein, human; C002963:geranylgeranyl pyrophosphate; C093642:SB 203580; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one