Abstract
Helicobacter pylori VacA induces multiple effects on susceptible cells, including vacuolation, mitochondrial damage, inhibition of cell growth, and enhanced cyclooxygenase-2 expression. To assess the ability of H. pylori to modulate the production of inflammatory mediators, we examined the mechanisms by which VacA enhanced IL-8 production by promonocytic U937 cells, which demonstrated the greatest VacA-induced IL-8 release of the cells tested. Inhibitors of p38 MAPK (SB203580), ERK1/2 (PD98059), IkBα ((E)-3-(4-methylphenylsulfonyl)-2-propenenitrile), Ca 2+ entry (SKF96365), and intracellular Ca 2+ channels (dantrolene) blocked VacA-induced IL-8 production. Furthermore, an intracellular Ca 2+ chelator (BAPTA-AM), which inhibited VacA-acti- vated p38 MAPK, caused a dose-dependent reduction in VacA-induced IL-8 secretion by U937 cells, implying a role for intra- cellular Ca 2+ in mediating activation of MAPK and the canonical NF-κB pathway. VacA stimulated translocation of NF-κBp65 to the nucleus, consistent with enhancement of IL-8 expression by activation of the NF-κB pathway. In addition, small interfering RNA of activating transcription factor (ATF)-2 or CREB, which is a p38MAPK substrate and binds to the AP-1 site of the IL-8 promoter, inhibited VacA-induced IL-8 production. VacA activated an IL-8 promoter containing an NF-IL-6 site, but not a mutated AP-1 or NF-κB site, suggesting direct involvement of the ATF-2/CREB binding region or NF-κB-binding regions in VacA-induced IL-8 promoter activation. Thus, in U937 cells, VacA directly increases IL-8 production by activation of the p38 MAPK via intracellular Ca 2+ release, leading to activation of the transcription factors, ATF-2, CREB, and NF-κB.
| Original language | English |
|---|---|
| Pages (from-to) | 5017-5027 |
| Number of pages | 11 |
| Journal | Journal of Immunology |
| Volume | 180 |
| Issue number | 7 |
| Publication status | Published - Apr 1 2008 |
| Externally published | Yes |
Fingerprint
ASJC Scopus subject areas
- Immunology
Cite this
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-κB Activation. / Hisatsune, Junzo; Nakayama, Masaaki; Isomoto, Hajime; Kurazono, Hisao; Mukaida, Naofumi; Mukhopadhyay, Asish K.; Azuma, Takeshi; Yamaoka, Yoshio; Sap, Jan; Yamasaki, Eiki; Yahiro, Kinnosuke; Moss, Joel; Hirayama, Toshiya.
In: Journal of Immunology, Vol. 180, No. 7, 01.04.2008, p. 5017-5027.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - 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-κB Activation
AU - Hisatsune, Junzo
AU - Nakayama, Masaaki
AU - Isomoto, Hajime
AU - Kurazono, Hisao
AU - Mukaida, Naofumi
AU - Mukhopadhyay, Asish K.
AU - Azuma, Takeshi
AU - Yamaoka, Yoshio
AU - Sap, Jan
AU - Yamasaki, Eiki
AU - Yahiro, Kinnosuke
AU - Moss, Joel
AU - Hirayama, Toshiya
PY - 2008/4/1
Y1 - 2008/4/1
N2 - Helicobacter pylori VacA induces multiple effects on susceptible cells, including vacuolation, mitochondrial damage, inhibition of cell growth, and enhanced cyclooxygenase-2 expression. To assess the ability of H. pylori to modulate the production of inflammatory mediators, we examined the mechanisms by which VacA enhanced IL-8 production by promonocytic U937 cells, which demonstrated the greatest VacA-induced IL-8 release of the cells tested. Inhibitors of p38 MAPK (SB203580), ERK1/2 (PD98059), IkBα ((E)-3-(4-methylphenylsulfonyl)-2-propenenitrile), Ca 2+ entry (SKF96365), and intracellular Ca 2+ channels (dantrolene) blocked VacA-induced IL-8 production. Furthermore, an intracellular Ca 2+ chelator (BAPTA-AM), which inhibited VacA-acti- vated p38 MAPK, caused a dose-dependent reduction in VacA-induced IL-8 secretion by U937 cells, implying a role for intra- cellular Ca 2+ in mediating activation of MAPK and the canonical NF-κB pathway. VacA stimulated translocation of NF-κBp65 to the nucleus, consistent with enhancement of IL-8 expression by activation of the NF-κB pathway. In addition, small interfering RNA of activating transcription factor (ATF)-2 or CREB, which is a p38MAPK substrate and binds to the AP-1 site of the IL-8 promoter, inhibited VacA-induced IL-8 production. VacA activated an IL-8 promoter containing an NF-IL-6 site, but not a mutated AP-1 or NF-κB site, suggesting direct involvement of the ATF-2/CREB binding region or NF-κB-binding regions in VacA-induced IL-8 promoter activation. Thus, in U937 cells, VacA directly increases IL-8 production by activation of the p38 MAPK via intracellular Ca 2+ release, leading to activation of the transcription factors, ATF-2, CREB, and NF-κB.
AB - Helicobacter pylori VacA induces multiple effects on susceptible cells, including vacuolation, mitochondrial damage, inhibition of cell growth, and enhanced cyclooxygenase-2 expression. To assess the ability of H. pylori to modulate the production of inflammatory mediators, we examined the mechanisms by which VacA enhanced IL-8 production by promonocytic U937 cells, which demonstrated the greatest VacA-induced IL-8 release of the cells tested. Inhibitors of p38 MAPK (SB203580), ERK1/2 (PD98059), IkBα ((E)-3-(4-methylphenylsulfonyl)-2-propenenitrile), Ca 2+ entry (SKF96365), and intracellular Ca 2+ channels (dantrolene) blocked VacA-induced IL-8 production. Furthermore, an intracellular Ca 2+ chelator (BAPTA-AM), which inhibited VacA-acti- vated p38 MAPK, caused a dose-dependent reduction in VacA-induced IL-8 secretion by U937 cells, implying a role for intra- cellular Ca 2+ in mediating activation of MAPK and the canonical NF-κB pathway. VacA stimulated translocation of NF-κBp65 to the nucleus, consistent with enhancement of IL-8 expression by activation of the NF-κB pathway. In addition, small interfering RNA of activating transcription factor (ATF)-2 or CREB, which is a p38MAPK substrate and binds to the AP-1 site of the IL-8 promoter, inhibited VacA-induced IL-8 production. VacA activated an IL-8 promoter containing an NF-IL-6 site, but not a mutated AP-1 or NF-κB site, suggesting direct involvement of the ATF-2/CREB binding region or NF-κB-binding regions in VacA-induced IL-8 promoter activation. Thus, in U937 cells, VacA directly increases IL-8 production by activation of the p38 MAPK via intracellular Ca 2+ release, leading to activation of the transcription factors, ATF-2, CREB, and NF-κB.
UR - http://www.scopus.com/inward/record.url?scp=44449153085&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=44449153085&partnerID=8YFLogxK
M3 - Article
C2 - 18354227
AN - SCOPUS:44449153085
VL - 180
SP - 5017
EP - 5027
JO - Journal of Immunology
JF - Journal of Immunology
SN - 0022-1767
IS - 7
ER -