Skip to main content

Helicobacter pylori VacA Reduces the Cellular Expression of STAT3 and Pro-survival Bcl-2 Family Proteins, Bcl-2 and Bcl-XL, Leading to Apoptosis in Gastric Epithelial Cells

Digestive Diseases and Sciences volume 56, pages 999–1006 (2011)Cite this article

Abstract

Background

Helicobacter pylori vacuolating cytotoxin, VacA, stimulates apoptosis via a mitochondria-dependent pathway. VacA induces apoptosis via activation of the pro-apoptotic B-cell lymphoma (Bcl)-2 family proteins, Bcl-2-associated X protein (Bax) and Bcl-2 homologous antagonist/killer (Bak), while the implication of such pro-survival Bcl-2 family members as Bcl-2 and Bcl-XL in the VacA-induced apoptosis remains unknown. Signal transduction and activator of transcription 3 (STAT3) is a pivotal transcription factor that upregulates Bcl-2 and Bcl-XL.

Aims

This study was conducted to elicit the implication of STAT3 and pro-survival Bcl-2 and Bcl-XL in the intrinsic apoptosis.

Methods

Immunoblot and reverse transcriptase real-time polymerase chain reaction (RT-PCR) were employed to assess the cellular expression of STAT3, Bcl-2, and Bcl-XL in response to purified VacA in gastric adenocarcinoma cell lines. VacA-induced apoptosis was quantitated morphologically following knockdown by each specific small interfering RNA (siRNA) or in the presence of pharmacological inhibitors.

Results

VacA reduced STAT3, Bcl-2, and Bcl-XL expression in a dose-dependent manner. Knockdown of STAT3, Bcl-2, and Bcl-XL by siRNA induced apoptosis to a similar extent in the case of sufficient VacA inoculation. The VacA-mediated reduction of STAT3 expression was independent of cellular vacuolization, since a vacuolar-type ATPase inhibitor, bafilomycin A1, did not inhibit VacA-induced reduction of STAT3, Bcl-2, and Bcl-XL expression. Instead, a c-JUN NH2-terminal kinase (JNK) inhibitor, SP600125, restored the VacA-induced reduction of STAT3 expression to the basal level.

Conclusions

VacA-induced apoptosis may be, in part, implicated in the reduction of STAT3 linking to the downregulation of Bcl-2 and Bcl-XL, in association with JNK activity.

This is a preview of subscription content, access via your institution.

Access options

Buy single article

Instant access to the full article PDF.

39,95 €

Price includes VAT (Finland)

Fig. 1a–c
Fig. 2a, b
Fig. 3
Fig. 4a–c
Fig. 5
Fig. 6a, b

References

  1. Blaser MJ, Atherton JC. Helicobacter pylori persistence: biology and disease. J Clin Invest. 2004;113:321–333.

    PubMed  CAS  Google Scholar 

  2. Kusters JG, van Vliet AH, Kuipers EJ. Pathogenesis of Helicobacter pylori infection. Clin Microbiol Rev. 2006;19:449–490.

    Article  PubMed  CAS  Google Scholar 

  3. McClain MS, Iwamoto H, Cao P, et al. Essential role of a GXXXG motif for membrane channel formation by Helicobacter pylori vacuolating toxin. J Biol Chem. 2003;278:12101–12108.

    Article  PubMed  CAS  Google Scholar 

  4. Cover TL, Reddy LY, Blaser MJ. Effects of ATPase inhibitors on the response of HeLa cells to Helicobacter pylori vacuolating toxin. Infect Immun. 1993;61:1427–1431.

    PubMed  CAS  Google Scholar 

  5. Cover TL, Hanson PI, Heuser JE. Acid-induced dissociation of VacA, the Helicobacter pylori vacuolating cytotoxin, reveals its pattern of assembly. J Cell Biol. 1997;138:759–769.

    Article  PubMed  CAS  Google Scholar 

  6. Boncristiano M, Paccani SR, Barone S, et al. The Helicobacter pylori vacuolating toxin inhibits T cell activation by two independent mechanisms. J Exp Med. 2003;198:1887–1897.

    Article  PubMed  CAS  Google Scholar 

  7. Sundrud MS, Torres VJ, Unutmaz D, et al. Inhibition of primary human T cell proliferation by Helicobacter pylori vacuolating toxin (VacA) is independent of VacA effects on IL-2 secretion. Proc Natl Acad Sci USA. 2004;101:7727–7732.

    Article  PubMed  CAS  Google Scholar 

  8. Tombola F, Carlesso C, Szabò I, et al. Helicobacter pylori vacuolating toxin forms anion-selective channels in planar lipid bilayers: possible implications for the mechanism of cellular vacuolation. Biophys J. 1999;76:1401–1409.

    Article  PubMed  CAS  Google Scholar 

  9. Wang F, Xia P, Wu F, et al. Helicobacter pylori VacA disrupts apical membrane-cytoskeletal interactions in gastric parietal cells. J Biol Chem. 2008;283:26714–26725.

    Article  PubMed  CAS  Google Scholar 

  10. Hisatsune J, Nakayama M, Isomoto H, et al. Molecular characterization of Helicobacter pylori VacA induction of IL-8 in U937 cells reveals a prominent role for p38MAPK in activating transcription factor-2, cAMP response element binding protein, and NF-kappaB activation. J Immunol. 2008;180:5017–5027.

    PubMed  CAS  Google Scholar 

  11. Nakayama M, Kimura M, Wada A, et al. Helicobacter pylori VacA activates the p38/activating transcription factor 2-mediated signal pathway in AZ-521 cells. J Biol Chem. 2004;279:7024–7028.

    Article  PubMed  CAS  Google Scholar 

  12. Yamasaki E, Wada A, Kumatori A, et al. Helicobacter pylori vacuolating cytotoxin induces activation of the proapoptotic proteins Bax and Bak, leading to cytochrome c release and cell death, independent of vacuolation. J Biol Chem. 2006;281:11250–11259.

    Article  PubMed  CAS  Google Scholar 

  13. Willhite DC, Blanke SR. Helicobacter pylori vacuolating cytotoxin enters cells, localizes to the mitochondria, and induces mitochondrial membrane permeability changes correlated to toxin channel activity. Cell Microbiol. 2004;6:143–154.

    Article  PubMed  CAS  Google Scholar 

  14. Galmiche A, Rassow J, Doye A, et al. The N-terminal 34 kDa fragment of Helicobacter pylori vacuolating cytotoxin targets mitochondria and induces cytochrome c release. EMBO J. 2000;19:6361–6370.

    Article  PubMed  CAS  Google Scholar 

  15. Mérino D, Bouillet P. The Bcl-2 family in autoimmune and degenerative disorders. Apoptosis. 2009;14:570–583.

    Article  PubMed  Google Scholar 

  16. Isomoto H. Epigenetic alterations in cholangiocarcinoma-sustained IL-6/STAT3 signaling in cholangio-carcinoma due to SOCS3 epigenetic silencing. Digestion. 2009;79(Suppl 1):2–8.

    Article  PubMed  CAS  Google Scholar 

  17. Yahiro K, Niidome T, Kimura M, et al. Activation of Helicobacter pylori VacA toxin by alkaline or acid conditions increases its binding to a 250-kDa receptor protein-tyrosine phosphatase beta. J Biol Chem. 1999;274:36693–36699.

    Article  PubMed  CAS  Google Scholar 

  18. Yoshida A, Isomoto H, Hisatsune J, et al. Enhanced expression of CCL20 in human Helicobacter pylori-associated gastritis. Clin Immunol. 2009;130:290–297.

    Article  PubMed  CAS  Google Scholar 

  19. Isomoto H, Kobayashi S, Werneburg NW, et al. Interleukin 6 upregulates myeloid cell leukemia-1 expression through a STAT3 pathway in cholangiocarcinoma cells. Hepatology. 2005;42:1329–1338.

    Article  PubMed  CAS  Google Scholar 

  20. Kimura M, Goto S, Wada A, et al. Vacuolating cytotoxin purified from Helicobacter pylori causes mitochondrial damage in human gastric cells. Microb Pathog. 1999;26:45–52.

    Article  PubMed  CAS  Google Scholar 

  21. Nakayama M, Hisatsune J, Yamasaki E, et al. Clustering of Helicobacter pylori VacA in lipid rafts, mediated by its receptor, receptor-like protein tyrosine phosphatase beta, is required for intoxication in AZ-521 Cells. Infect Immun. 2006;74:6571–6580.

    Article  PubMed  CAS  Google Scholar 

  22. Gao LY, Kwaik YA. The modulation of host cell apoptosis by intracellular bacterial pathogens. Trends Microbiol. 2000;8:306–313.

    Article  PubMed  CAS  Google Scholar 

  23. Ham M, Kaunitz JD. Gastroduodenal mucosal defense. Curr Opin Gastroenterol. 2008;24:665–673.

    Article  PubMed  CAS  Google Scholar 

  24. Ganten TM, Aravena E, Sykora J, et al. Helicobacter pylori-induced apoptosis in T cells is mediated by the mitochondrial pathway independent of death receptors. Eur J Clin Invest. 2007;37:117–125.

    Article  PubMed  CAS  Google Scholar 

  25. Isomoto H, Moss J, Hirayama T. Pleiotropic actions of Helicobacter pylori vacuolating cytotoxin, VacA. Tohoku J Exp Med. 2010;220:3–14.

    Article  PubMed  CAS  Google Scholar 

  26. Bronte-Tinkew DM, Terebiznik M, Franco A, et al. Helicobacter pylori cytotoxin-associated gene A activates the signal transducer and activator of transcription 3 pathway in vitro and in vivo. Cancer Res. 2009;69:632–639.

    Article  PubMed  CAS  Google Scholar 

  27. Oldani A, Cormont M, Hofman V, et al. Helicobacter pylori counteracts the apoptotic action of its VacA toxin by injecting the CagA protein into gastric epithelial cells. PLoS Pathog. 2009;5:e1000603.

    Article  PubMed  Google Scholar 

  28. Yokoyama K, Higashi H, Ishikawa S, et al. Functional antagonism between Helicobacter pylori CagA and vacuolating toxin VacA in control of the NFAT signaling pathway in gastric epithelial cells. Proc Natl Acad Sci USA. 2005;102:9661–9666.

    Article  PubMed  CAS  Google Scholar 

  29. Wada A, Yamasaki E, Hirayama T. Helicobacter pylori vacuolating cytotoxin, VacA, is responsible for gastric ulceration. J Biochem. 2004;136:741–746.

    Article  PubMed  CAS  Google Scholar 

  30. Ricci V, Galmiche A, Doye A, et al. High cell sensitivity to Helicobacter pylori VacA toxin depends on a GPI-anchored protein and is not blocked by inhibition of the clathrin-mediated pathway of endocytosis. Mol Biol Cell. 2000;11:3897–3909.

    PubMed  CAS  Google Scholar 

  31. Schraw W, Li Y, McClain MS, van der Goot FG, et al. Association of Helicobacter pylori vacuolating toxin (VacA) with lipid rafts. J Biol Chem. 2002;277:34642–34650.

    Article  PubMed  CAS  Google Scholar 

  32. Hisatsune J, Yamasaki E, Nakayama M, et al. Helicobacter pylori VacA enhances prostaglandin E2 production through induction of cyclooxygenase 2 expression via a p38 mitogen-activated protein kinase/activating transcription factor 2 cascade in AZ-521 cells. Infect Immun. 2007;75:4472–4481.

    Article  PubMed  CAS  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki University School of Medicine, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan

    Ayako Matsumoto, Yoshito Nishi & Shigeru Kohno

  2. Department of Gastroenterology and Hepatology, Nagasaki University Hospital, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan

    Hajime Isomoto, Yujiro Nakashima, Kayoko Matsushima & Kazuhiko Nakao

  3. Department of Bacteriology, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan

    Masaaki Nakayama, Junzo Hisatsune & Toshiya Hirayama

  4. Department of Applied Veterinary Medicine and Public Health, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, 080-8555, Japan

    Hisao Kurazono

Authors
  1. Ayako Matsumoto
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Hajime Isomoto
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Masaaki Nakayama
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Junzo Hisatsune
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Yoshito Nishi
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Yujiro Nakashima
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Kayoko Matsushima
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Hisao Kurazono
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. Kazuhiko Nakao
    View author publications

    You can also search for this author in PubMed Google Scholar

  10. Toshiya Hirayama
    View author publications

    You can also search for this author in PubMed Google Scholar

  11. Shigeru Kohno
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Hajime Isomoto.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Matsumoto, A., Isomoto, H., Nakayama, M. et al. Helicobacter pylori VacA Reduces the Cellular Expression of STAT3 and Pro-survival Bcl-2 Family Proteins, Bcl-2 and Bcl-XL, Leading to Apoptosis in Gastric Epithelial Cells. Dig Dis Sci 56, 999–1006 (2011). https://doi.org/10.1007/s10620-010-1420-1

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10620-010-1420-1

Keywords

  • Vacuolating cytotoxin, VacA
  • Signal transduction and activator of transcription 3, STAT3
  • B-cell lymphoma (Bcl)-2 and Bcl-XL
  • c-JUN NH2-terminal kinase, JNK
  • Apoptosis