Research On The Fuction Of Immune-related Genes Induced By LPS In The Immune System

Outside pathogenic microorganisms can invade the body in different pathways, and cause disease through various mechanism. When the pathogenic microorganism pass over the epithelial barrier of human body, and start reproducing in the organization of the host, it will be identified by the mononuclear phagocytes and macrophages in the organization. Macrophages can rapid reaction when the body encounters invasion by pathogenic microorganism. On the one hand, it can engulf pathogens. On the other hand, it can release a lot of effect molecular and cause inflammation, then control infection.The process of antigens recognition of the body's immune system relies on different PRR (pattern recognition receptors), such as TLRs(Toll like receptors),NLRs (NOD-like receptors),RLH(sRIG-like helicases), and so on. As an important part in innate immunity, TLRs can cause an immune response, and remove foreign antigen by recognizing the PAMPs (pathogen associated molecular patterns) on the surface of the pathogenic microorganisms.LPS (Lipopolysaccharide) is the composition of cell walls of gram-negative bacteria. It can cause some changes of immune cells, such as cell morphologic,function and the intracellular gene expression, and lead to many diseases occurring, for example, cytokines expression out of control,serious infection,organ damage and septic shock, and so on. Research shows that LPS can be recognited by TLR4 on the surface of cells, and transmit the signals to intracellular, activate multiple signaling pathways, such as MAPK(Mitogen activated protein kinase),NF-κB(Nuclear factor kappa light chain enhancer of activated B cells),AKT/PKB signaling pathway. It will trigger the secretion of a series of natural immune molecules, such as cytokine and chemotactic, including Interleukin-1 (IL-1) and TNF alpha (Tumor necrosis factor alpha), IL-6 (Interleukin-6), IL-12 (Interleukin-12),IL-8 (Interleukin-8), etc. TLR family can not only? cause natural immune response, control the inflammatory response in the nature,intensity and duration, but also upregulated the expression of co-stimulate molecule and MHCⅡon the surface of APCs( antigen presenting cells). It can also promote the mature of the APCs and take part in antigen specific immune response, especially the production of Th1 cells, adjust the strength and types of acquired immune response. It becomes a bridge in connecting innate immunity and acquired immune. However, activating excessive or shortage of TLR signals will both cause the body function abnormality and disease. TLRs pathways are controlled by many other signaling pathways in positive or negative ways. It is very important to maintain appropriate activation in balance.Lots of proteins involved in the regulation process of TLR4 signal transduction pathways by induced LPS. There is only some key molecules research deeply at present. LPS stimulated cells can cause the changes of many gene expression which regulating its signal pathways. It still difficulty to screen these genes and explore their function. Contrast the EST database of activation spleen organization of mice with unactivation state, we get some genes that maybe play potential roles in the immune system. We will do some research on these genes. This article introduces two genes, Sik1 and Rab10. Result shows there are some certain trend of the expression of Rab10 and Sik1 under LPS stimulate DC (dendritic cell) in different time. It suggests that Rab10 and Sik1 maybe play roles in immune regulation.In the research of Rab10 project, we explore the function of Rab10 in vitro by overexpressing Rab10 in RAW264.7 cells and macrophages and constructing two cell lines of Rab10 silencing stability, Rab10iA and Rab10KD251. Finally, we use an in vivo model of mice acute lung injury to check its fuctions. Research results show that Rab10 protein plays an important role in TLR4 signal transduction by LPS induced. Rab10 protein can improve the promoter activity of IFN-β,NF-κB, strengthen MAPK,NF-κB,IRF-3 signaling pathways, upregulate the expression of cytokines by LPS stimulating, such as TNF-a,IL-6,IFN-β. The mechanism of Rab10 is that it can assiste TLR4 transship to cell membranes from the Golgi, and enhance the TLR4 signaling pathways induced by LPS, regulate the immune response.In the research of Sik1 project, we overexpressed Sik1 in RAW264.7 and RNA interference in DC by using virus vectors, and checked its effect on cytokine expression. Research results show that Sik1 can enhance the MAPK,NF-κB signaling pathways, improve transcriptional activity of NF-κB, promote the expression of proinflammatory factor, such as IL-6,IL-12,TNF-a, restrain the expression of anti-inflammation factors, such as IL -10.