BACKGROUND: Helicobacter pylori, a gram negative bacterium, colonizes the stomach in a majority of the world population. The two major virulence factors of H. pylori VacA and CagA, thought to be associated with chronic inflammation and disease, have been extensively studied, but the regulation of the expression of these virulence genes in H. pylori remains poorly understood. METHODS: qRT-PCR was performed to quantify gene expression in unadhered and AGS-adhered H. pylori. Δfur mutant was constructed by splicing by overlap extension PCR and allelic exchange. RESULTS: Adherence of H. pylori to the gastric epithelial cell line AGS strongly induces the expression of both cagA and vacA. Induction of cagA and vacA in the AGS cell-adhered H. pylori Δfur mutant strain was consistently lower than in the adhered parent strain. However, expression of the genes was similar between the wild-type and Δfur mutant strains in the unadhered state, suggesting that Fur has a role in the upregulation of cagA and vacA expression, especially in AGS-adhered H. pylori. Consistent with these results, microscopic observations revealed that infection of AGS cells with H. pylori Δfur mutant strain produced much less damage as compared to that produced by the wild-type H. pylori strain. CONCLUSIONS: These results suggested that cagA and vacA gene expression is upregulated in H. pylori, especially by host cell contact, and Fur has a role in the upregulation.
BACKGROUND:Helicobacter pylori, a gram negative bacterium, colonizes the stomach in a majority of the world population. The two major virulence factors of H. pylori VacA and CagA, thought to be associated with chronic inflammation and disease, have been extensively studied, but the regulation of the expression of these virulence genes in H. pylori remains poorly understood. METHODS: qRT-PCR was performed to quantify gene expression in unadhered and AGS-adhered H. pylori. Δfur mutant was constructed by splicing by overlap extension PCR and allelic exchange. RESULTS: Adherence of H. pylori to the gastric epithelial cell line AGS strongly induces the expression of both cagA and vacA. Induction of cagA and vacA in the AGS cell-adhered H. pylori Δfur mutant strain was consistently lower than in the adhered parent strain. However, expression of the genes was similar between the wild-type and Δfur mutant strains in the unadhered state, suggesting that Fur has a role in the upregulation of cagA and vacA expression, especially in AGS-adhered H. pylori. Consistent with these results, microscopic observations revealed that infection of AGS cells with H. pylori Δfur mutant strain produced much less damage as compared to that produced by the wild-type H. pylori strain. CONCLUSIONS: These results suggested that cagA and vacA gene expression is upregulated in H. pylori, especially by host cell contact, and Fur has a role in the upregulation.
Authors: María G Cárdenas-Mondragón; Miguel A Ares; Leonardo G Panunzi; Sabino Pacheco; Margarita Camorlinga-Ponce; Jorge A Girón; Javier Torres; Miguel A De la Cruz Journal: Front Microbiol Date: 2016-11-22 Impact factor: 5.640
Authors: Emma C Skoog; Médea Padra; Anna Åberg; Pär Gideonsson; Ikenna Obi; Macarena P Quintana-Hayashi; Anna Arnqvist; Sara K Lindén Journal: Sci Rep Date: 2017-01-20 Impact factor: 4.379
Authors: Rosario Morales-Espinosa; Gabriela Delgado; Luis-Roberto Serrano; Elizabeth Castillo; Carlos A Santiago; Rigoberto Hernández-Castro; Alberto Gonzalez-Pedraza; Jose L Mendez; Luis F Mundo-Gallardo; Joaquín Manzo-Merino; Sergio Ayala; Alejandro Cravioto Journal: PLoS One Date: 2020-03-12 Impact factor: 3.240