Cytochalasin D Stimulation of Tyrosine Phosphorylation and Phosphotyrosine-Associated Kinase Activity in Vascular Smooth Muscle Cells

1998 ◽  
Vol 245 (3) ◽  
pp. 646-650 ◽  
Author(s):  
Husna Abedi ◽  
Ian Zachary
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Tyrosine Phosphorylation ◽  
Vascular Smooth Muscle Cells ◽  
Kinase Activity ◽  
Muscle Cells ◽  
Cytochalasin D ◽  
Stimulation Of

Effects of Angiotensin II Type 2 Receptor Stimulation on Collagen Synthesis in Vascular Smooth Muscle Cells

Hypertension ◽  
2000 ◽  
Vol 36 (suppl_1) ◽  
pp. 709-709
Author(s):  
Mizuo Mifune ◽  
Hiroyuki Sasamura ◽  
Hideaki Nakaya ◽  
Ryoko Shimizu-Hirota ◽  
Matsuhiko Hayashi ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Collagen Synthesis ◽  
Tyrosine Phosphatase ◽  
Muscle Cells ◽  
At2 Receptor ◽  
Stimulation Of

P84 Previously, we and others have shown that angiotensin II enhances vascular smooth muscle cell extracellular matrix synthesis via stimulation of the type 1 angiotensin (AT1) receptor. Recently, expression of the type 2 (AT2) receptor has been confirmed in the adult vasculature, but its role in vascular remodeling has not yet been fully defined. In particular, conflicting data from in vivo studies have reported that AT2 receptor inhibition may either attenuate or enhance vascular hypertrophy and fibrosis. The aim of this study was to clarify the effects of direct stimulation of AT2 receptors on collagen synthesis in vascular smooth muscle cells in vitro. Firstly, retroviral gene transfer was used to supplement adult vascular smooth muscle cells with AT2 receptors to mimic the vasculature in vivo. Treatment of these cells with the AT2 receptor agonist CGP42212A (10-7 mol/L) alone did not cause a significant change in p42/p44 MAP kinase activity, but caused a modest (33%) decrease in protein tyrosine phosphatase activity. Treatment with CGP42112A also caused a dose- and time-dependent increase in both cell-associated and secretory collagen synthesis (148+17% of control at 48 h, p<0.05) which was completely inhibited by the AT2 receptor antagonist PD123319, but unaffected by the AT1 receptor antagonist losartan. The AT2 receptor-mediated stimulation of collagen synthesis was unaffected by tyrosine phosphatase inhibitors sodium orthovanadate and okadaic acid, but attenuated by pretreatment with pertussis toxin or Galphai antisense oligonuclotides. These results suggest that direct AT2 receptor stimulation can increase rather than decrease collagen synthesis in vascular smooth muscle cells, and suggest a role for Galphai in the AT2 receptor-mediated effects.

scholarly journals Neuropilin-1 mediates PDGF stimulation of vascular smooth muscle cell migration and signalling via p130Cas

2011 ◽  
Vol 435 (3) ◽  
pp. 609-618 ◽  
Author(s):  
Caroline Pellet-Many ◽  
Paul Frankel ◽  
Ian M. Evans ◽  
Birger Herzog ◽  
Manfred Jünemann-Ramírez ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Growth Factor ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Tyrosine Phosphorylation ◽  
Muscle Cells ◽  
Immunofluorescent Staining ◽  
Human Coronary Artery ◽  
Neuropilin 1 ◽  
Stimulation Of

NRP1 (neuropilin-1) is a co-receptor for members of the VEGF (vascular endothelial growth factor) family in endothelial cells, but is increasingly implicated in signalling induced by other growth factors. NRP1 is expressed in VSMCs (vascular smooth muscle cells), but its function and the mechanisms involved are poorly understood. The present study aimed to determine the role of NRP1 in the migratory response of HCASMCs (human coronary artery smooth muscle cells) to PDGF (platelet-derived growth factor), and to identify the signalling mechanisms involved. NRP1 is highly expressed in HAoSMCs (human aortic smooth muscle cells) and HCASMCs, and modified in VSMCs by CS (chondroitin sulfate)-rich O-linked glycosylation at Ser612. HCASMC migration induced by PDGF-BB and PDGF-AA was inhibited by NRP1 siRNA (small interfering RNA), and by adenoviral overexpression of an NRP1 mutant lacking the intracellular domain (Ad.NRP1ΔC). NRP1 co-immunoprecipitated with PDGFRα (PDGF receptor α), and immunofluorescent staining indicated that NRP1 and PDGFRα co-localized in VSMCs. NRP1 siRNA also inhibited PDGF-induced PDGFRα activation. NRP1-specific siRNA, Ad.NRP1ΔC and removal of CS glycans using chondroitinase all inhibited PDGF-BB and -AA stimulation of tyrosine phosphorylation of the adapter protein, p130Cas (Cas is Crk-associated substrate), with little effect on other major signalling pathways, and p130Cas knockdown inhibited HCASMC migration. Chemotaxis and p130Cas phosphorylation induced by PDGF were inhibited by chondroitinase, and, additionally, adenoviral expression of a non-glycosylatable NRP1S612A mutant inhibited chemotaxis, but not p130Cas phosphorylation. These results indicate a role for NRP1 and NRP1 glycosylation in mediating PDGF-induced VSMC migration, possibly by acting as a co-receptor for PDGFRα and via selective mobilization of a novel p130Cas tyrosine phosphorylation pathway.

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