title: Static strain stimulates expression of matrix metalloproteinase-2 and VEGF in microvascular endothelium via JNK- and ERK-dependent pathways.
abstract: VEGF and MMP protein production are both required for exercise-induced capillary growth in skeletal muscle. The underlying process by which muscle activity initiates an angiogenic response is not established, but it is known that mechanical forces such as muscle stretch are involved. We hypothesized that stretch of skeletal muscle microvascular endothelial cells induces production of MMP-2 and VEGF through a common signal pathway. Endothelial cells were grown on Bioflex plates and exposed to 10% static stretch for up to 24 h. MMP-2 protein level was measured by gelatin zymography and VEGF, MMP-2, and MT1-MMP mRNA levels were quantified by real-time quantitative PCR. ERK1/2 and JNK phosphorylation and VEGF protein levels were assessed by Western blotting. Effects of mitogen-activated protein kinases (MAPKs) (ERK1/2, JNK) and reactive oxygen species (ROS) on stretch-induced expression of MMP-2 and VEGF were tested using pharmacological inhibitors. Stretching of endothelial cells for 24 h caused significant increases in MMP-2 protein and mRNA level, but no change in MT1-MMP mRNA. While MMP-2 protein production was enhanced by H(2)O(2) in unstretched cells, ROS inhibition during stretch did not diminish MMP-2 mRNA or protein production. Inhibition of JNK suppressed stretch-induced MMP-2 protein and mRNA, but inhibition of ERK had no effect. In contrast, inhibition of ERK but not JNK attenuated the stretch-induced increase in VEGF mRNA. Our results demonstrate that differential regulation of MMP-2 and VEGF by MAPK signal pathways contribute to stretch-induced activation of microvascular endothelial cells.
authors.affiliation: Department of Laboratory Diagnostics and Molecular Medicine, Pomeranian Medical University, Szczecin, Poland.
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Milkiewicz
authors.forename: Forough
authors.initials: F
authors.lastname: Mohammadzadeh
authors.forename: Eric
authors.initials: E
authors.lastname: Ispanovic
authors.forename: Eric
authors.initials: E
authors.lastname: Gee
authors.forename: Tara L
authors.initials: TL
authors.lastname: Haas
mesh_terms: D000818:Animals; D004730:Endothelium, Vascular / Q000201:enzymology / Q000378:metabolism*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D048670:MAP Kinase Kinase 4 / Q000378:metabolism*; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000098:blood supply / Q000378:metabolism; D018919:Neovascularization, Physiologic; D016133:Polymerase Chain Reaction; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species; D048049:Extracellular Signal-Regulated MAP Kinases; D048670:MAP Kinase Kinase 4; D020778:Matrix Metalloproteinase 2