Original Article
Copyright ©2012 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Feb 7, 2012; 18(5): 425-434
Published online Feb 7, 2012. doi: 10.3748/wjg.v18.i5.425
Effect of Helicobacter pylori cdrA on interleukin-8 secretions and nuclear factor kappa B activation
Hiroaki Takeuchi, Ya-Nan Zhang, Dawn A Israel, Richard M Peek Jr, Mikio Kamioka, Hideo Yanai, Norihito Morimoto, Tetsuro Sugiura
Hiroaki Takeuchi, Mikio Kamioka, Norihito Morimoto, Tetsuro Sugiura, Department of Clinical Laboratory Medicine, Kochi Medical School, Kohasu, Oko-cho, Nankoku-city, Kochi 783-8505, Japan
Ya-Nan Zhang, Laboratory Department, Beijing Tiantan Hospital Affiliated of Capital Medical University, Beijing 100050, China
Dawn A Israel, Richard M Peek Jr, Division of Gastroenterology and Cancer Prevention, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, United States
Hideo Yanai, Department of Internal Medicine, Kanmon Medical Center, 1-1-1 Ushiroda-cho, Shimonoseki, Yamaguchi 751-8501, Japan
Author contributions: Takeuchi H designed and performed the research, and wrote the paper; Zhang YN and Kamioka M performed the research; Peek Jr RM, Yanai H, Morimoto N and Sugiura T contributed new reagents/analytic tools; Israel DA revised the paper.
Supported by The Project Research Fund from Kochi University, to Takeuchi H; and a Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture of Japan, No. 21590631 and 21590629, in part
Correspondence to: Dr. Hiroaki Takeuchi, Department of Clinical Laboratory Medicine, Kochi Medical School, Kohasu, Oko-cho, Nankoku-city, Kochi 783-8505, Japan. htake@kochi-u.ac.jp
Telephone: +81-88-8802427 Fax: +81-88-8802428
Received: April 15, 2011
Revised: May 19, 2011
Accepted: May 26, 2011
Published online: February 7, 2012
Abstract

AIM: To investigate genetic diversity of Helicobacter pylori (H. pylori) cell division-related gene A (cdrA) and its effect on the host response.

METHODS: Inactivation of H. pylori cdrA, which is involved in cell division and morphological elongation, has a role in chronic persistent infections. Genetic property of H. pylori cdrA was evaluated using polymerase chain reaction and sequencing in 128 (77 American and 51 Japanese) clinical isolates obtained from 48 and 51 patients, respectively. Enzyme-linked immunosorbent assay was performed to measure interleukin-8 (IL-8) secretion with gastric biopsy specimens obtained from American patients colonized with cdrA-positive or -negative strains and AGS cells co-cultured with wild-type HPK5 (cdrA-positive) or its derivative HPKT510 (cdrA-disruptant). Furthermore, the cytotoxin-associated gene A (cagA) status (translocation and phosphorylation) and kinetics of transcription factors [nuclear factor-kappa B (NF-κB) and inhibition kappa B] were investigated in AGS cells co-cultured with HPK5, HPKT510 and its derivative HPK5CA (cagA-disruptant) by western blotting analysis with immunoprecipitation.

RESULTS: Genetic diversity of the H. pylori cdrA gene demonstrated that the cdrA status segregated into two categories including four allele types, cdrA-positive (allele types;Iand II) and cdrA-negative (allele types; III and IV) categories, respectively. Almost all Japanese isolates were cdrA-positive (I: 7.8% and II: 90.2%), whereas 16.9% of American isolates were cdrA-positive (II) and 83.1% were cdrA-negative (III: 37.7% and IV: 45.5%), indicating extended diversity of cdrA in individual American isolates. Comparison of each isolate from different regions (antrum and corpus) in the stomach of 29 Americans revealed that cdrA status was identical in both isolates from different regions in 17 cases. However, 12 cases had a different cdrA allele and 6 of them exhibited a different cdrA category between two regions in the stomach. Furthermore, in 5 of the 6 cases possessing a different cdrA category, cdrA-negative isolate existed in the corpus, suggesting that cdrA-negative strain is more adaptable to colonization in the corpus. IL-8 secretions from AGS revealed that IL-8 levels induced by a cdrA-disrupted HPKT510 was significantly lower (P < 0.01) compared to wild-type HPK5: corresponding to 50%-60% of those of wild-type HPK5. These data coincided with in vivo data that an average value of IL-8 in biopsy specimens from cdrA-positive and cdrA-negative groups was 215.6 and 135.9 pg/mL, respectively. Western blotting analysis documented that HPKT510 had no effect on CagA translocation and phosphorylation, however, nuclear accumulation of NF-κB was lower by HPKT510 compared to HPK5.

CONCLUSION: Colonization by a cdrA-negative or cdrA-dysfunctional strain resulted in decreased IL-8 production and repression of NF-κB, and hence, attenuate the host immunity leading to persistent infection.

Keywords: Helicobacter pylori cell division-related gene A; Genetic diversity; Host immune response; Interleukin-8 secretion; Nuclear factor kappa B; Persistent infection