Initial signaling of the fibronectin receptor (α5β1 integrin) in hepatic stellate cells is independent of tyrosine phosphorylation

Milliano, Michael T.; Luxon, Bruce A.

doi:10.1016/s0168-8278(03)00161-2

Cited by 35 publications

(21 citation statements)

References 23 publications

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“…However, as shown in this study, the expression of DG and laminin and the changes in cellular distribution could also play a role in cell migration during activation of HSC. Culture-activated HSC/ myofibroblasts also express FN (9, 25), a protein known to induce the activated phenotype of HSC (25). As shown in this work, culture-activated HSC/myofibroblasts express ␣5-integrin, and this FN receptor colocalizes with FN.…”

Section: Discussionsupporting

confidence: 62%

The role of dystroglycan in PDGF-BB-dependent migration of activated hepatic stellate cells/myofibroblasts

Kastanis¹,

Hernández‐Nazará

Nieto

et al. 2011

American Journal of Physiology-Gastrointestinal and Liver Physi

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This extracellular matrix contains several basement membrane components including laminin, but its composition changes during liver injury because of the production of extracellular matrix components found in scar tissue. These changes in extracellular matrix composition and in cell-extracellular matrix interactions may play a key role in hepatic stellate cell transdifferentiation. In this communication we used early passages of mouse hepatic stellate cells (activated HSC/ myofibroblasts) to study the platelet-derived growth factor BB (PDGF-BB)-dependent expression and regulation of ␤-dystroglycan and its role in activated HSC/myofibroblast migration. We used Northern and Western analysis to study dystroglycan expression and confocal microscopy to investigate changes in subcellular distribution of the protein. Activated HSC migration was investigated using an in vitro wound-healing assay. PDGF-BB induced significant changes in dystroglycan regulation and subcellular distribution of the protein.Whereas steady-state levels of dystroglycan mRNA remained constant, PDGF-BB increased dystroglycan transcription but shortened the t 1/2 by 50%. Moreover, PDGF-BB changed dystroglycan and ␣5-integrin cellular distribution. Cell migration experiments revealed that PDGF-BB-dependent migration of activated HSC/myofibroblasts was completely blocked by neutralizing antibodies to fibronectin, ␣5-integrin, laminin, and ␤-dystroglycan. Overall, these findings suggest that both laminin and fibronectin and their receptors play a key role in PDGF-BB-induced activated HSC migration.platelet-derived growth factor; HSC activation; fibronectin; laminin; ␣5-integrin HEPATIC STELLATE CELLS (HSC), the main collagen producing cells of the liver, are localized to the perisinusoidal space of Disse and are embedded in a loose connective tissue matrix. This space is devoid of a continuous basement membrane but contains collagens, laminins, and fibronectins (FN) (23). Several liver cell types participate in the production of the extracellular matrix found in the space of Disse although HSC contribute to the production of type IV collagen and laminin (12). Quiescent HSC are characterized by their high content of vitamin A and triglycerides that are the basis for their isolation (28). Upon liver injury, HSC change phenotype and are transformed into myofibroblasts or activated HSC that express multiple growth factor receptors, including platelet-derived growth factor receptor-␤ (PDGF-␤r). Similar events to those observed in vivo during HSC activation can be reproduced when culturing the cells on plastic, collagen, and/or FN-coated culture dishes (21). In contrast with these findings, cultureactivated HSC/myofibroblasts on a laminin-rich gel (Matrigel) stimulates the maintenance of a quiescent state (11) and reverts the myofibroblastic phenotype (31).Dystroglycan (DG) is a laminin-binding protein involved in cell-matrix interaction. It is produced as a large molecularweight protein that upon proteolytic cleavage generates the two DG subunits (␣ and ␤...

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Section: Discussionsupporting

confidence: 62%

The role of dystroglycan in PDGF-BB-dependent migration of activated hepatic stellate cells/myofibroblasts

Kastanis¹,

Hernández‐Nazará

Nieto

et al. 2011

American Journal of Physiology-Gastrointestinal and Liver Physi

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“…The FN receptor (a5b1 integrin) is increasingly expressed during activation of HSC and binding to its ligand in the ECM induces activation of multiple kinase pathways and collagen synthesis. 59 Integrin avb3, a receptor for FN or vitronectin, regulates proliferation and apoptosis of HSC. 60 The main components of Matrigel, laminin and Col IV, are ligands for several b1 integrins, and antagonizing this integrin consequently inhibited adhesion of HSC to Matrigel.…”

Section: Deactivation Of Pancreatic Stellate Cells R Jesnowski Et Almentioning

confidence: 99%

Immortalization of pancreatic stellate cells as an in vitro model of pancreatic fibrosis: deactivation is induced by matrigel and N-acetylcysteine

Jesnowski

Fürst

Ringel

et al. 2005

Laboratory Investigation

132

134

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Tissue fibrosis is one of the characteristics of chronic pancreatitis and pancreatic adenocarcinoma. Activated pancreatic stellate cells (PSC) play a central role in this process. However, analysis of the molecular mechanisms leading to PSC activation is hampered by the lack of an established human PSC line. To overcome this problem, we immortalized and characterized primary human PSC. The cells were isolated by the outgrowth method and were immortalized by transfection with SV40 large T antigen and human telomerase (hTERT). Primary human PSC served as controls. An immortalized line, RLT-PSC, was analyzed for the expression of stellate cell markers. Moreover, the effects of transforming growth factor b 1(TGFb1) or platelet-derived growth factor stimulation and of cultivation on basement membrane components or N-acetylcysteine (NAC) treatment on gene and protein expression and proliferation were analyzed. Immortal RLT-PSC cells retained the phenotype of activated PSC proven by the expression of a-smooth muscle actin (aSMA), vimentin, desmin and glial fibrillary acidic protein (GFAP). TGFb1 treatment upregulated the expression of aSMA, collagen type I (Col I), fibronectin and TGFb1. Incubation of RLT-PSC cells and primary human activated PSC on Matrigel plus NAC treatment resulted in a deactivated phenotype as evidenced by a decrease of aSMA, connective tissue growth factor and Col I expression and by a decreased proliferation of the cells. Moreover, this treatment restored the ability of the cells to store vitamin A in cytoplasmic vesicles. In conclusion, we have established an immortal pancreatic stellate cell line, without changing the characteristic phenotype. Importantly, we were able to demonstrate that besides soluble factors, the matrix surrounding PSC plays a pivotal role in the maintenance of the activation process of PSC. Cultivation of activated PSC on a reconstituted basement membrane plus treatment with NAC was able to deactivate the cells, thus pointing to the possibility of an antifibrosis therapy in chronic pancreatitis.

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“…The ␣ 5 ␤ 1 integrin signal induces activation of FAK and MAP kinase. FAK in association with Src activates downstream effector molecules either directly or through activation of phosphatidylinositol 3 kinase (7,15,35,49). Our inhibition assay suggests that Omp100 activates fibronectin-integrin ␣ 5 ␤ 1 and is possibly associated with FAK and Src, which are involved in activation of MAP kinase (Fig.…”

Section: Discussionmentioning

confidence: 69%

Actinobacillus actinomycetemcomitansOuter Membrane Protein 100 Triggers Innate Immunity and Production of β-Defensin and the 18-Kilodalton Cationic Antimicrobial Protein through the Fibronectin-Integrin Pathway in Human Gingival Epithelial Cells

Ouhara¹,

Komatsuzawa²,

Shiba

et al. 2006

Infect Immun

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Antimicrobial peptides, human ␤-defensin (hBD), and the 18-kDa cationic antimicrobial protein (CAP18) are components of innate immunity. These peptides have antimicrobial activity against bacteria, fungi, and viruses. Actinobacillus actinomycetemcomitans is a gram-negative facultative anaerobe implicated in the initiation of periodontitis. The innate immunity peptides have antibacterial activity against A. actinomycetemcomitans. We investigated the molecular mechanism of human gingival epithelial cells (HGEC) responding to exposure to A. actinomycetemcomitans. HGEC constitutively express hBD1 and inducibly express hBD2, hBD3, and CAP18 on exposure to A. actinomycetemcomitans. The level of expression varies among clinical isolates. In the signaling pathway for hBD2 induction by the bacterial contact, we demonstrate that the mitogen-activated protein (MAP) kinase and not the NF-B transcription factor pathway is used. We found the outer membrane protein 100 (Omp100; identified by molecular mass) is the component inducing the hBD2 response. Omp100 binds to fibronectin, an extracellular matrix inducing hBD2 via the MAP kinase pathway. Anti-integrin ␣ 5 ␤ 1 , antifibronectin, genistein, and PP2 suppress the Omp100-induced expression of hBD2, suggesting that Src kinase is involved through integrin ␣ 5 ␤ 1 . The inflammatory cytokines, tumor necrosis factor ␣ (TNF-␣), interleukin-1␤ (IL-1␤), IL-6 and IL-8, produced by HGEC on contact with A. actinomycetemcomitans also stimulate expression of hBD2. Further, neutralizing antibody against TNF-␣ or IL-8 partially inhibits the induction of hBD2 on bacterial contact. Therefore, we found that the induction of the antimicrobial peptides is mediated by a direct response principally through an Omp100-fibronectin interaction, and using secondary stimulation by inflammatory cytokines induced by the bacterial exposure.

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Initial signaling of the fibronectin receptor (α5β1 integrin) in hepatic stellate cells is independent of tyrosine phosphorylation

Cited by 35 publications

References 23 publications

The role of dystroglycan in PDGF-BB-dependent migration of activated hepatic stellate cells/myofibroblasts

The role of dystroglycan in PDGF-BB-dependent migration of activated hepatic stellate cells/myofibroblasts

Immortalization of pancreatic stellate cells as an in vitro model of pancreatic fibrosis: deactivation is induced by matrigel and N-acetylcysteine

Actinobacillus actinomycetemcomitansOuter Membrane Protein 100 Triggers Innate Immunity and Production of β-Defensin and the 18-Kilodalton Cationic Antimicrobial Protein through the Fibronectin-Integrin Pathway in Human Gingival Epithelial Cells

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