Urokinase-receptor-mediated phenotypic changes in vascular smooth muscle cells require the involvement of membrane rafts

2009 ◽  
Vol 423 (3) ◽  
pp. 343-351 ◽  
Author(s):  
Julia Kiyan ◽  
Graham Smith ◽  
Hermann Haller ◽  
Inna Dumler

The cholesterol-enriched membrane microdomains lipid rafts play a key role in cell activation by recruiting and excluding specific signalling components of cell-surface receptors upon receptor engagement. Our previous studies have demonstrated that the GPI (glycosylphosphatidylinositol)-linked uPAR [uPA (urokinase-type plasminogen activator) receptor], which can be found in lipid rafts and in non-raft fractions, can mediate the differentiation of VSMCs (vascular smooth muscle cells) towards a pathophysiological de-differentiated phenotype. However, the mechanism by which uPAR and its ligand uPA regulate VSMC phenotypic changes is not known. In the present study, we provide evidence that the molecular machinery of uPAR-mediated VSMC differentiation employs lipid rafts. We show that the disruption of rafts in VSMCs by membrane cholesterol depletion using MCD (methyl-β-cyclodextrin) or filipin leads to the up-regulation of uPAR and cell de-differentiation. uPAR silencing by means of interfering RNA resulted in an increased expression of contractile proteins. Consequently, disruption of lipid rafts impaired the expression of these proteins and transcriptional activity of related genes. We provide evidence that this effect was mediated by uPAR. Similar effects were observed in VSMCs isolated from Cav1−/− (caveolin-1-deficient) mice. Despite the level of uPAR being significantly higher after the disruption of the rafts, uPA/uPAR-dependent cell migration was impaired. However, caveolin-1 deficiency impaired only uPAR-dependent cell proliferation, whereas cell migration was strongly up-regulated in these cells. Our results provide evidence that rafts are required in the regulation of uPAR-mediated VSMC phenotypic modulations. These findings suggest further that, in the context of uPA/uPAR-dependent processes, caveolae-associated and non-associated rafts represent different signalling membrane domains.

2005 ◽  
Vol 33 (11) ◽  
pp. 1546-1554 ◽  
Author(s):  
Hak-Joon Sung ◽  
Suzanne G. Eskin ◽  
Yumiko Sakurai ◽  
Andrew Yee ◽  
Noriyuki Kataoka ◽  
...  

2010 ◽  
Vol 45 (2) ◽  
pp. 87-97 ◽  
Author(s):  
Ping Jiang ◽  
Jinwen Xu ◽  
Shuhui Zheng ◽  
Jinghe Huang ◽  
Qiuling Xiang ◽  
...  

Atherosclerosis is an inflammatory disease where lipopolysaccharide (LPS) triggers the release of inflammatory cytokines that accelerate its initiation and progression. Estrogen has been proven to be vasoprotective against atherosclerosis; however, the anti-inflammatory function of estrogen in the vascular system remains obscure. In this study, we investigated the effect of estrogen on LPS-induced monocyte chemoattractant protein-1 (MCP-1; listed as CCL2 in the MGI database) production in vascular smooth muscle cells (VSMCs). LPS significantly enhances MCP-1 production and this is dependent on nuclear factor κ B (NFκB) signaling, since the use of NFκB inhibitor pyrrolidine dithiocarbamate or the silencing of NFκB subunit p65 expression with specific siRNA largely impairs LPS-enhanced MCP-1 production. On the contrary, 17β-estradiol (E2) inhibits LPS-induced MCP-1 production in a time- and dose-dependent manner, which is related to the suppression of p65 translocation to nucleus. Furthermore, p38 MAPK is rapidly activated in response to LPS, while E2 markedly inhibits p38 MAPK activation. Transfection with p38 MAPK siRNA or the use of p38 MAPK inhibitor SB203580 markedly attenuates LPS-stimulated p65 translocation to nucleus and MCP-1 production, suggesting that E2 suppresses NFκB signaling by the inactivation of p38 MAPK signaling. LPS promotes VSMCs migration and this is abrogated by MCP-1 antibody, implying that MCP-1 may play a major role as an autocrine factor in atherosclerosis. In addition, E2 inhibits LPS-promoted cell migration by downregulation of MCP-1 production. Overall, our results demonstrate that E2 exerts anti-inflammatory property antagonistic to LPS in VSMCs by reducing MCP-1 production, and this effect is related to the inhibition of p38 MAPK/NFκB cascade.


2020 ◽  
Vol 98 (2) ◽  
pp. 249-257
Author(s):  
Qiang Xue ◽  
Xiaoli Wang ◽  
Xiaohui Deng ◽  
Yue Huang ◽  
Wei Tian

In this study we investigated the regulatory role of cell-migration-inducing and hyaluronan-binding protein (CEMIP) in the proliferation and migration of vascular smooth muscle cells (VSMCs). The mRNA and protein levels of CEMIP were upregulated in the plasma samples from patients with atherosclerosis, and in VSMCs stimulated with platelet-derived growth factor-BB (PDGF-BB), compared with plasma from healthy subjects and untreated VSMCs. Silencing CEMIP suppressed PDGF-BB-induced cell migration and proliferation in VSMCs, as determined using a Cell Counting Kit-8 assays, 5-ethynyl-2′-deocyuridine (EDU) assays, flow cytometry, wound healing assays, and Transwell assays. Overexpression of CEMIP promoted the proliferation and migration of VSMCs via activation of the Wnt–β-catenin signaling pathway and the upregulation of its target genes, including matrix metalloproteinase-2, matrix metalloproteinase-7, cyclin D1, and c-myc, whereas CEMIP deficiency showed the opposite effects. The knockdown of CEMIP in ApoE−/− mice by intravenous injection of lentiviral vector expressing si-CEMIP protected against high-fat-diet-induced atherosclerosis, as shown by the reduced aortic lesion areas, aortic sinus lesion areas, and the concentration of blood lipids compared with mice normally expressing CEMIP. These results demonstrated that CEMIP regulates the proliferation and migration of VSMCs in atherosclerosis by activating the WNT–β-catenin signaling pathway, which suggests the therapeutic potential of CEMIP for the management of atherosclerosis.


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