Impact of sub-inhibitory concentrations of amoxicillin on helicobacter pylori virulence factors

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Processo FAPESP: 2009/1598-7

Helicobacter pylori are etiological factor of human acute and chronic gastritis. Critical host responses that influence the progression to H. pylori-induced carcinogenesis include gastric inflammation. This study was conducted to evaluate whether subinhibitory concentrations of amoxicillin can affect H. pylori-induced cytokines by RAW 264.7 macrophage-like cells. In addition, a proteomic approach was used to compare H. pylori protein expression profiles under amoxicillin treatment. H. pylori ATCC 43504 was cultured with or without amoxicillin at subinhibitory concentrations (sub-MICs). The cytokines (IL 1-β, IL-6, IL-12, and TNF-α) released by infected RAW 264.7 cells were quantified by a sandwich immunoassay. Differential protein analysis of H. pylori was performed using 2-dimensional electrophoresis (2-DE) followed by mass spectrometry and the sequences were searched against the SWISS-PROT data bank. Pre-treatment H. pylori with sub-MIC of amoxicillin increased IL-1β and IL-12 production by RAW 264.7 cells. Proteomics analyses of proteins revealed that the sub-MIC treatment affected the expression of several classes of proteins. Among the nine most over expressed proteins included heat shock proteins, superoxide dismutase, enolase, ATP synthase alpha subunit, neutrophil activating protein and argininosuccinate synthase. The results shown in the present work indicate that sub-MICs of amoxicillin can induce specific changes on the cell wall proteins and behavior of susceptible H. pylori that can contribute to the pathogenesis of the bacterium.