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Increased expression of the urokinase plasminogen activator system by Helicobacter pylori in gastric epithelial cells.

Kenny S, Duval C, Sammut SJ, Steele I, Pritchard DM, Atherton JC, Argent RH, Dimaline R, Dockray GJ, Varro A - Am. J. Physiol. Gastrointest. Liver Physiol. (2008)

Bottom Line: Real-time PCR of biopsies from gastric corpus, but not antrum, showed significantly increased PAI-1, uPA, and uPAR in H. pylori-positive patients.H. pylori also stimulated soluble and cell surface-bound uPA activity, and both were further increased by PAI-1 knockdown, consistent with PAI-1 inhibition of endogenous uPA.H. pylori induction of uPA therefore leads to epithelial proliferation through activation of HB-EGF and is normally inhibited by concomitant induction of PAI-1; treatments directed at inhibition of uPA may slow the progression to gastric cancer.

View Article: PubMed Central - PubMed

Affiliation: Physiological Laboratory, School of Biomedical Sciences, University of Liverpool, Crown St., Liverpool L69 3BX, UK.

ABSTRACT
The gastric pathogen Helicobacter pylori (H. pylori) is linked to peptic ulcer and gastric cancer, but the relevant pathophysiological mechanisms are unclear. We now report that H. pylori stimulates the expression of plasminogen activator inhibitor (PAI)-1, urokinase plasminogen activator (uPA), and its receptor (uPAR) in gastric epithelial cells and the consequences for epithelial cell proliferation. Real-time PCR of biopsies from gastric corpus, but not antrum, showed significantly increased PAI-1, uPA, and uPAR in H. pylori-positive patients. Transfection of primary human gastric epithelial cells with uPA, PAI-1, or uPAR promoters in luciferase reporter constructs revealed expression of all three in H+/K+ATPase- and vesicular monoamine transporter 2-expressing cells; uPA was also expressed in pepsinogen- and uPAR-containing trefoil peptide-1-expressing cells. In each case expression was increased in response to H. pylori and for uPA, but not PAI-1 or uPAR, required the virulence factor CagE. H. pylori also stimulated soluble and cell surface-bound uPA activity, and both were further increased by PAI-1 knockdown, consistent with PAI-1 inhibition of endogenous uPA. H. pylori stimulated epithelial cell proliferation, which was inhibited by uPA immunoneutralization and uPAR knockdown; exogenous uPA also stimulated proliferation that was further increased after PAI-1 knockdown. The proliferative effects of uPA were inhibited by immunoneutralization of the EGF receptor and of heparin-binding EGF (HB-EGF) by the mutant diphtheria toxin CRM197 and an EGF receptor tyrosine kinase inhibitor. H. pylori induction of uPA therefore leads to epithelial proliferation through activation of HB-EGF and is normally inhibited by concomitant induction of PAI-1; treatments directed at inhibition of uPA may slow the progression to gastric cancer.

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H. pylori increases both cell surface-bound and soluble uPA activity, and PAI-1 knockdown increases activity still further. A: cell surface-bound uPA activity after H. pylori infection with or without PAI-1 antisense oligonucleotide (PAI-1-ASO, 2 μM) treatment expressed as % of control. B: soluble uPA activity after H. pylori infection with or without PAI-1-ASO treatment expressed as % of control. In control cells, the cell surface uPA amounted to 48 ± 7% of soluble activity; n = 5–13, P < 0.05, ANOVA (*control vs. H. pylori; **H. pylori alone vs. H. pylori with PAI-1 knockdown).
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f5: H. pylori increases both cell surface-bound and soluble uPA activity, and PAI-1 knockdown increases activity still further. A: cell surface-bound uPA activity after H. pylori infection with or without PAI-1 antisense oligonucleotide (PAI-1-ASO, 2 μM) treatment expressed as % of control. B: soluble uPA activity after H. pylori infection with or without PAI-1-ASO treatment expressed as % of control. In control cells, the cell surface uPA amounted to 48 ± 7% of soluble activity; n = 5–13, P < 0.05, ANOVA (*control vs. H. pylori; **H. pylori alone vs. H. pylori with PAI-1 knockdown).

Mentions: Since both uPA and its inhibitor PAI-1 were increased by H. pylori, we asked whether there were changes in uPA enzyme activity. Infection of cultured gastric glands with H. pylori increased both cell surface-bound and soluble uPA activity (Fig. 5). We then examined the consequences of PAI-1 knockdown. Immunohistochemistry confirmed that PAI-1 antisense oligonucleotide treatment significantly decreased the total number of cells in cultured gastric glands expressing endogenous PAI-1 (CSO, 10.0 ± 0.3% vs. ASO, 3.8 ± 0.2%). Moreover, PAI-1 knockdown (Fig. 5, A and B) increased both cell surface-bound and soluble uPA activity although the increase was more marked for the latter than the former.


Increased expression of the urokinase plasminogen activator system by Helicobacter pylori in gastric epithelial cells.

Kenny S, Duval C, Sammut SJ, Steele I, Pritchard DM, Atherton JC, Argent RH, Dimaline R, Dockray GJ, Varro A - Am. J. Physiol. Gastrointest. Liver Physiol. (2008)

H. pylori increases both cell surface-bound and soluble uPA activity, and PAI-1 knockdown increases activity still further. A: cell surface-bound uPA activity after H. pylori infection with or without PAI-1 antisense oligonucleotide (PAI-1-ASO, 2 μM) treatment expressed as % of control. B: soluble uPA activity after H. pylori infection with or without PAI-1-ASO treatment expressed as % of control. In control cells, the cell surface uPA amounted to 48 ± 7% of soluble activity; n = 5–13, P < 0.05, ANOVA (*control vs. H. pylori; **H. pylori alone vs. H. pylori with PAI-1 knockdown).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2536790&req=5

f5: H. pylori increases both cell surface-bound and soluble uPA activity, and PAI-1 knockdown increases activity still further. A: cell surface-bound uPA activity after H. pylori infection with or without PAI-1 antisense oligonucleotide (PAI-1-ASO, 2 μM) treatment expressed as % of control. B: soluble uPA activity after H. pylori infection with or without PAI-1-ASO treatment expressed as % of control. In control cells, the cell surface uPA amounted to 48 ± 7% of soluble activity; n = 5–13, P < 0.05, ANOVA (*control vs. H. pylori; **H. pylori alone vs. H. pylori with PAI-1 knockdown).
Mentions: Since both uPA and its inhibitor PAI-1 were increased by H. pylori, we asked whether there were changes in uPA enzyme activity. Infection of cultured gastric glands with H. pylori increased both cell surface-bound and soluble uPA activity (Fig. 5). We then examined the consequences of PAI-1 knockdown. Immunohistochemistry confirmed that PAI-1 antisense oligonucleotide treatment significantly decreased the total number of cells in cultured gastric glands expressing endogenous PAI-1 (CSO, 10.0 ± 0.3% vs. ASO, 3.8 ± 0.2%). Moreover, PAI-1 knockdown (Fig. 5, A and B) increased both cell surface-bound and soluble uPA activity although the increase was more marked for the latter than the former.

Bottom Line: Real-time PCR of biopsies from gastric corpus, but not antrum, showed significantly increased PAI-1, uPA, and uPAR in H. pylori-positive patients.H. pylori also stimulated soluble and cell surface-bound uPA activity, and both were further increased by PAI-1 knockdown, consistent with PAI-1 inhibition of endogenous uPA.H. pylori induction of uPA therefore leads to epithelial proliferation through activation of HB-EGF and is normally inhibited by concomitant induction of PAI-1; treatments directed at inhibition of uPA may slow the progression to gastric cancer.

View Article: PubMed Central - PubMed

Affiliation: Physiological Laboratory, School of Biomedical Sciences, University of Liverpool, Crown St., Liverpool L69 3BX, UK.

ABSTRACT
The gastric pathogen Helicobacter pylori (H. pylori) is linked to peptic ulcer and gastric cancer, but the relevant pathophysiological mechanisms are unclear. We now report that H. pylori stimulates the expression of plasminogen activator inhibitor (PAI)-1, urokinase plasminogen activator (uPA), and its receptor (uPAR) in gastric epithelial cells and the consequences for epithelial cell proliferation. Real-time PCR of biopsies from gastric corpus, but not antrum, showed significantly increased PAI-1, uPA, and uPAR in H. pylori-positive patients. Transfection of primary human gastric epithelial cells with uPA, PAI-1, or uPAR promoters in luciferase reporter constructs revealed expression of all three in H+/K+ATPase- and vesicular monoamine transporter 2-expressing cells; uPA was also expressed in pepsinogen- and uPAR-containing trefoil peptide-1-expressing cells. In each case expression was increased in response to H. pylori and for uPA, but not PAI-1 or uPAR, required the virulence factor CagE. H. pylori also stimulated soluble and cell surface-bound uPA activity, and both were further increased by PAI-1 knockdown, consistent with PAI-1 inhibition of endogenous uPA. H. pylori stimulated epithelial cell proliferation, which was inhibited by uPA immunoneutralization and uPAR knockdown; exogenous uPA also stimulated proliferation that was further increased after PAI-1 knockdown. The proliferative effects of uPA were inhibited by immunoneutralization of the EGF receptor and of heparin-binding EGF (HB-EGF) by the mutant diphtheria toxin CRM197 and an EGF receptor tyrosine kinase inhibitor. H. pylori induction of uPA therefore leads to epithelial proliferation through activation of HB-EGF and is normally inhibited by concomitant induction of PAI-1; treatments directed at inhibition of uPA may slow the progression to gastric cancer.

Show MeSH
Related in: MedlinePlus