Project description:Helicobacter pylori, a gastroenteric pathogen believed to have co-evolved with humans for 100.000 years, has a high genetic variability that motivates the study of different H. pylori populations and the diseases caused by them in order to find determinants for disease evolution. In this study we utilized both genomic and proteomic tools to compare a H. pylori strain (Nic25_A) from Nicaragua isolated from a patient with intestinal metaplasia with the P12 strain from Europe isolated from a patient with duodenal ulcer. Differences in the protein expression levels between the two strains were determined by both label-free quantification (MaxQuant) and labelling methods (tandem mass tags, TMT), utilizing a lipid-based protein immobilization (LPI™) technique to target surface protein peptides. Using the MaxQuant software, we found 52 proteins significantly differing between the two strains (up-or-down regulated by a factor of 1.5) and with TMT we were able to find 18 proteins with different expression levels between the strains. The P12 (duodenal ulcer) strain had higher expression of genes belonging to the cagPAI operon, while Nic25_A (intestinal metaplasia) had higher expression of the acid response regulator ArsR, as well as proteins regulated by ArsR; KatA, AmiE, and proteins involved in urease production. The results show that differences in protein expression can be detected by proteomic approaches in H. pylori strains of different pathogenicity, which might have implications for studies of disease progression.
Project description:Helicobacter pylori enhances the risk for ulcer disease and gastric cancer, yet only a minority of H. pylori-colonized individuals develop disease. We examined the ability of two H. pylori isolates to induce differential host responses in vivo or in vitro, and then used an H. pylori whole genome microarray to identify bacterial determinants related to pathogenesis. Gastric ulcer strain B128 induced more severe gastritis, proliferation, and apoptosis in gerbil mucosa than did duodenal ulcer strain G1.1, and gastric ulceration and atrophy occurred only in B128+ gerbils. In vitro, gerbil-passaged B128 derivatives significantly increased IL-8 secretion and apoptosis compared with G1.1 strains. DNA hybridization to the microarray identified several strain-specific differences in gene composition including a large deletion of the cag pathogenicity island in strain G1.1. Partial and complete disruption of the cag island in strain B128 attenuated induction of IL-8 in vitro and significantly decreased gastric inflammation in vivo. These results indicate that the ability of H. pylori to regulate epithelial cell responses related to inflammation depends on the presence of an intact cag pathogenicity island. Use of an H pylori whole genome microarray is an effective method to identify differences in gene content between H. pylori strains that induce distinct pathological outcomes in a rodent model of H. pylori infection. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Keywords: Logical Set
Project description:Helicobacter pylori enhances the risk for ulcer disease and gastric cancer, yet only a minority of H. pylori-colonized individuals develop disease. We examined the ability of two H. pylori isolates to induce differential host responses in vivo or in vitro, and then used an H. pylori whole genome microarray to identify bacterial determinants related to pathogenesis. Gastric ulcer strain B128 induced more severe gastritis, proliferation, and apoptosis in gerbil mucosa than did duodenal ulcer strain G1.1, and gastric ulceration and atrophy occurred only in B128+ gerbils. In vitro, gerbil-passaged B128 derivatives significantly increased IL-8 secretion and apoptosis compared with G1.1 strains. DNA hybridization to the microarray identified several strain-specific differences in gene composition including a large deletion of the cag pathogenicity island in strain G1.1. Partial and complete disruption of the cag island in strain B128 attenuated induction of IL-8 in vitro and significantly decreased gastric inflammation in vivo. These results indicate that the ability of H. pylori to regulate epithelial cell responses related to inflammation depends on the presence of an intact cag pathogenicity island. Use of an H pylori whole genome microarray is an effective method to identify differences in gene content between H. pylori strains that induce distinct pathological outcomes in a rodent model of H. pylori infection. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Computed
Project description:Genome-wide association study with machine-learning between H. pylori gastric-cancer and duodenal-ulcer strain reveal discriminatory amino acid differences and novel oncoprotein candidates