tailieunhanh - Báo cáo y học: "The inflammatory cytokine tumor necrosis factor modulates the expression of Salmonella typhimurium effector proteins"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: The inflammatory cytokine tumor necrosis factor modulates the expression of Salmonella typhimurium effector proteins. | Ma et al. Journal of Inflammation 2010 7 42 http content 7 1 42 JOURNAL OF INFLAMMATION RESEARCH Open Access The inflammatory cytokine tumor necrosis factor modulates the expression of Salmonella typhimurium effector proteins Jun MaH Yong-guo Zhang1t Yinglin Xia3 Jun Sun1 2 4 Abstract Tumor necrosis factor a TNF-a is a host inflammatory factor. Bacteria increase TNF-a expression in a variety of human diseases including infectious diseases inflammatory bowel diseases and cancer. It is unknown however how TNF-a directly modulates bacterial protein expression during intestinal infection and chronic inflammation. In the current study we hypothesize that Salmonella typhimurium senses TNF-a and show that TNF-a treatment modulates Salmonella virulent proteins called effectors thus changing the host-bacterial interaction in intestinal epithelial cells. We investigated the expression of 23 Salmonella effectors after TNF-a exposure. We found that TNF-a treatment led to differential effector expression effector SipA was increased by TNF-a treatment whereas the expression levels of other effectors including gogB and spvB decreased in the presence of TNF-a. We verified the protein expression of Salmonella effectors AvrA and SipA by Western blots. Furthermore we used intestinal epithelial cells as our experimental model to explore the response of human intestinal cells to TNF-a pretreated Salmonella. More bacterial invasion was found in host cells colonized with Salmonella strains pretreated with TNF-a compared to Salmonella without TNF-a treatment. TNF-a pretreated Salmonella induced higher proinflammatory JNK signalling responses compared to the Salmonella strains without TNF-a exposure. Exposure to TNF-a made Salmonella to induce more inflammatory cytokine IL-8 in intestinal epithelial cells. JNK inhibitor treatment was able to suppress the effects of TNF-pretreated-Salmonella in enhancing expressions of phosphorylated-JNK and c-jun and secretion