1. Subendothelial cells from normal bovine arteries exhibit autonomous growth and constitutively activated intracellular signaling.
- Author
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Frid MG, Aldashev AA, Nemenoff RA, Higashito R, Westcott JY, and Stenmark KR
- Subjects
- Angiotensin II pharmacology, Animals, Anticoagulants pharmacology, Aorta, Thoracic cytology, Becaplermin, Blood Proteins pharmacology, Cattle, Cell Division drug effects, Cell Division physiology, Cell Size physiology, Culture Media, Conditioned pharmacology, Culture Media, Serum-Free pharmacology, Cyclooxygenase 2, Dinoprostone biosynthesis, Endothelin-1 pharmacology, Epoprostenol biosynthesis, GTP-Binding Proteins agonists, GTP-Binding Proteins antagonists & inhibitors, GTP-Binding Proteins metabolism, Gene Expression Regulation, Enzymologic, Isoenzymes metabolism, MAP Kinase Signaling System drug effects, Mitogen-Activated Protein Kinase 1 genetics, Mitogen-Activated Protein Kinase 1 metabolism, Mitogen-Activated Protein Kinase 3, Mitogen-Activated Protein Kinases genetics, Mitogen-Activated Protein Kinases metabolism, Muscle, Smooth, Vascular cytology, Muscle, Smooth, Vascular enzymology, Paracrine Communication drug effects, Paracrine Communication physiology, Phospholipases A metabolism, Platelet-Derived Growth Factor pharmacology, Prostaglandin-Endoperoxide Synthases metabolism, Proto-Oncogene Proteins c-sis, Pulmonary Artery cytology, Tunica Media cytology, Vasoconstrictor Agents pharmacology, Endothelium, Vascular cytology, Endothelium, Vascular enzymology, MAP Kinase Signaling System physiology
- Abstract
The arterial media is comprised of heterogeneous smooth muscle cell (SMC) subpopulations with markedly different growth responses to pathophysiological stimuli. Little information exists regarding the intracellular signaling pathways that contribute to these differences. Therefore, we investigated the growth-related signaling pathways in a unique subset of subendothelial SMCs (L1 cells) from normal, mature, bovine arteries and compared them with those in "traditional" SMCs derived from the middle media (L2 SMCs). Subendothelial L1 cells exhibited serum-independent autonomous growth, not observed in L2 SMCs. Autonomous growth of L1 cells was driven largely by the constitutively activated extracellular signal-regulated kinase (ERK-1/2) cascade. Inhibition of upstream activators of ERKs (MAP kinase kinase-1, p21(ras), receptor tyrosine kinases, and Gi protein-coupled receptors) led to suppression of autonomous growth in these cells. L1 cells also exhibited constitutive activation of important downstream targets of ERKs (cytosolic phospholipase A(2), cyclooxygenase-2) and secreted large amounts of prostaglandins. Importantly, L1 cells secreted potent mitogenic factor(s), which could potentially contribute in an autocrine fashion to the constitutive activation of these cells. Our data suggest that unique arterial cells with autonomous growth potential and constitutively activated signaling pathways exist in normal arteries and may contribute selectively to the pathogenesis of vascular diseases.
- Published
- 1999
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