Journal Article

Effects of Helicobacter pylori and Nitrate-Reducing Bacteria Coculture on Cells

Matsushita, Osamu, Watanabe, Akari, Okanoue, Shyoutarou, Okada, Hiroyuki, Yokota, Kenji, Gotoh, Kazuyoshi, Kuraoka, Sakiko, Ojima, Hinako

2022

Overview

Helicobacter pylori infection is an important risk factor for developing gastric cancer. However, only a few H. pylori-infected people develop gastric cancer. Thus, other risk factors aside from H. pylori infection may be involved in gastric cancer development. This study aimed to investigate whether the nitrate-reducing bacteria isolated from patients with atrophic gastritis caused by H. pylori infection are risk factors for developing atrophic gastritis and gastric neoplasia. Nitrate-reducing bacteria were isolated from patients with atrophic gastritis caused by H. pylori infection. Among the isolated bacteria, Actinomyces oris, Actinomyces odontolyticus, Rothia dentocariosa, and Rothia mucilaginosa were used in the subsequent experiments. Cytokine inducibility was evaluated in monocytic cells, and mitogen-activated protein kinase (MAPK) activity and cell cycle were assessed in the gastric epithelial cells. The cytotoxicities and neutrophil-inducing abilities of the Actinomyces and Rothia species were enhanced when cocultured with H. pylori. Th1/Th2-related cytokines were also expressed, but their expression levels differed depending on the bacterial species. Moreover, H. pylori and Actinomyces activated MAPK (ERK and p38) and affected cell cycle progression. Some nitrate-reducing bacteria cocultured with H. pylori may promote inflammation and atrophy by inducing cytokine production. In addition, the MAPK activation and cell cycle progression caused by these bacteria can contribute to gastric cancer development.

• Publisher: MDPI AG,MDPI
• Subject: Actinomyces / Actinomyces odontolyticus / Antibodies / Atrophy / Bacteria / Biopsy / Cancer / carcinogenesis / Cell activation / Cell cycle / coculture / Cytokines / Denitrifying bacteria / DNA polymerase / Epithelial cells / Epithelium / Extracellular signal-regulated kinase / Gastric cancer / Gastritis / Gene expression / Genetic testing / Helicobacter pylori / IL-8 / Infections / inflammation / Kinases / Leukocytes (neutrophilic) / Lymphocytes T / MAP kinase / mitogen-activated protein kinase / Monocytes / nitrate-reducing bacteria / Nitrates / people / Protein kinase / Risk analysis / Risk factors / Rothia dentocariosa / Rothia mucilaginosa / Signal transduction / stomach neoplasms / TNF-α / Tumor necrosis factor-TNF