AUTHOR=Zheng Wei , Miao Jing , Luo Lingling , Long Gao , Chen Bo , Shu Xiaoli , Gu Weizhong , Peng Kerong , Li Fubang , Zhao Hong , Botchway Benson O. A. , Fang Marong , Jiang Mizu 

TITLE=The Effects of Helicobacter pylori Infection on Microbiota Associated With Gastric Mucosa and Immune Factors in Children

JOURNAL=Frontiers in Immunology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2021.625586

DOI=10.3389/fimmu.2021.625586

ISSN=1664-3224

ABSTRACT=<sec><title>Background</title><p><italic>Helicobacter pylori</italic> infection is the main cause of chronic gastritis in children. Little is known about the effect of <italic>Helicobacter pylori</italic> on microbiota and immunity. This study was aimed at characterizing stomach microbiota and immune-regulatory properties of children with <italic>Helicobacter pylori</italic> colonization.</p></sec><sec><title>Methods</title><p>We studied 122 children who had undergone gastric endoscopy due to gastrointestinal symptoms, 57 were diagnosed with <italic>Helicobacter pylori</italic> infection. Endoscopic mucosal biopsy samples were obtained for DNA and RNA extraction. Microbiomes were analyzed by 16S rRNA profiling, with the differentially expressed genes analyzed using RNA sequencing. The RNA-sequencing results of selected genes were validated by qRT-PCR.</p></sec><sec><title>Results</title><p>Bacterial diversity of <italic>Helicobacter pylori</italic>-positive gastric specimens were lower than those of negative, and both groups were clearly separated according to beta diversity. <italic>Helicobacter pylori</italic>-positive group significantly reduced proportions of six phyla and eight genera; only <italic>Helicobacter</italic> taxa were more abundant in <italic>Helicobacter pylori-</italic>negative group. Gastric tissues RNA sequencing showed increased expression of multiple immune response genes in <italic>Helicobacter pylori</italic> -infection. <italic>Helicobacter pylori</italic> -infected children with restructured gastric microbiota had higher levels of FOXP3, IL-10, TGF-β1 and IL-17A expressions, which were consistent with increased CD4<sup>+</sup>T cell and macrophagocyte, compared with non-infected children.</p></sec><sec><title>Conclusions</title><p>Presence of <italic>Helicobacter pylori</italic> significantly influences gastric microbiota and results in lower abundance of multiple taxonomic levels in children. Meanwhile, it affects gastric immune environment and promotes the occurrence of gastritis.</p></sec><sec><title>Clinical Trial Registration</title><p>[<uri xlink:href="http://www.chictr.org.cn" xmlns:xlink="http://www.w3.org/1999/xlink">http://www.chictr.org.cn</uri>], identifier [ChiCTR1800015190]</p></sec>