The Proteomics Analysis of Exosomes Revealed the Possible Function of HSPD1 Protein in Helicobacter pylori Infection

Abstract Background: Exosomes containing various protein components play important roles in cell communication. In the present study, a systematic proteomic analysis of exosomes obtained from H. pylori infected cells was performed. Methods: Exosomes were evaluated by nanoparticle tracking analysis, transmission electron microscopy and western blotting. The recognized protein components were quantified by label-free proteomics and subjected to bioinformatics assays. The expression of HSPD1 in exosomes, host cells and gastric cancers infected by H. pylori was determined by western blotting and immunohistochemical respectively. In addition, the apoptotic regulation mechanisms of HSPD1 in H. pylori infection were analyzed by western blotting and flow cytometry. Results: A total of 120 important differential proteins were recognized in the exosomes from H. pylori -infected cells and subjected to Gene Ontology analysis. Among them, CD63 and HSP-70 were verified via western blotting. Moreover, HSPD1 expression was significantly increased, while ERK1/2 expression was markedly decreased in the exosomes from H. pylori -infected GES-1 cells. H. pylori infection promoted an abnormal increase in HSPD1 expression in GES-1 cells, AGS cells, gastric mucosa and gastric cancer according to western blotting and multicolor immunohistochemistry.In addition, knockdown of HSPD1 suppressed the apoptosis of infected cells and the expression of Bcl2, and promoted the upregulation of Bax, as determined through flow cytometry and western blotting. Conclusion: The present study provided a comprehensive proteomic description of exosomes from H. pylori -infected cells, and found that HSPD1 may play important roles in the process of H. pylori infection.