Effects Of FKN On P38 And NF-κB In Human PBMC And The Function Of Ras

Atherosclerosis (AS) is a disease which caused by many kinds of causes. A variety of factors can cause its occurrence. The inflammatory mechanism more and more are attracted. Chemokines are a group chemotactic cytokines with the function of chemotaxis.The inflammatory mechanism more and more are attracted. Chemokines are a group chemotactic cytokines with the function of chemotaxis. They attract immune cells to the immune response spot, and can attract the immune cell to the immune response partial. Therefore they play an important role in inflammatory response. Chemokines mainly are produced by leucocyte. However, a variety of somatic cells can also synthesize and secrete them, such as keratinocyte, renal glomerulus cell, epithelial cell, liver cell, fibroblast, mesenchymal cell, platelet, vascular endothelial cell and smooth muscle cell.Fractalkine (FKN) is one kind of recent discovery chemokine,it is overexspressed in the atherosclerotic plaque. It is a special chemokine with two forms—membrane-bound and water-soluble type .It plays an indispensable role in migrating and adherring to peripheral blood leukocyte. Compared with other chenmokines, it has two functions. One is Chemotaxis, the other is intercellular adhesion. Its unique feature also affirms this point. The largest difference between FKN and other chemokines is that it is a transmembrane glycoprotein. Membrane-bound FKN mediated leukocyte adhesion does not to need other adherence members, thus it might play a unique role in biological function and the occurrence and development process of disease. Numerous studies show that it plays an important role in the occurrence and development of AS. Therefore, the research about its signal transduction mechanism, regulation and control mechanisms, clinical significance will certainly to be helpful in clearing about the role which acts in a series of physiological pathology process. It will provide the recent clue for the coronal atherosclerosis disease's prevention and treatment. It will seek new therapeutic targets and strategies for clinical disease.Ras is a small guanylate-binding protein. Its biological activity can be controlled by the adjustable GDP / GTP cycle. It is an important protein which regulates cell growth transduction. Ras protein substrate is the serine / threonine kinases, including Raf-1, MAPKK and MAPK. Mitogen-activated protein kinase—MAPK is the common pathway and the central link which transmit extracellular signal to the nucleus and causing cell proliferation and hypertrophic response. The P38 is a new MAPK super family member. It plays a crucial role in cell differentiation. As an important signaling protein, p38 kinase participates in cell's survival, differentiation and growth process. It is considered that the meeting point of the transmission of information and common pathway. Research has shown that Phosphorylation p38 MAPK can lead to IκBa and Iκkinase (Iκ-K) phosphorylation, resulting in the activation of NF-κB. And nuclear factor-κB—NF-κB is a transcription factor which is composed of Rel/NF-κB family's multi-peptide members. In resting cells, latent in the cytoplasm of NF-κB and IκB (the inhibitor of NF-κB) combined with each other. When they are stimulated, the stimulation can cause the degradation of IκB protein. After the IκB protein degradated, NF-κB to be released, and can be transferred to the nucleus, then activate a series of homologous gene. Many coding genes in atherosclerosis injured Subject to the regulation of NF-κB, including the gene of TNF-α.Experiments have proved that FKN may cause NF-κB activation in cells, then giving rise to a series of inflammatory response. Some experiments also proved that there was Ras-MAPK coupling NF-κB signal transduction way. Then whether FKN does cause NF-κB activation through Ras/p38 this circuit? In this study, we make FKN, Ras, p38 and NF-κB relate to together for exploring their relations and roles in human mononuclear cells.Objective: To investigate the function of FKN in atherosclerosis. We also investigate that FKN affects on the progress of the expression of NF-κB in mononuclear cells, and they relate with the Ras/p38MAPK signal transduction circuit.Significance: To clear FKN to lie between leads the uninuclear cell adherency and hastens the concrete function mechanism.To seek inhibitor for the Ras/p38/NF-κB circuit. To provide the foundation theory study for the development of AS disease. To provide the rationale and follow the card medicine evidence for treating AS disease.Methods: Peripheral blood monocyte is isolated from fresh blood of healthy volunteers by Ficoll-Paque gradient centrifugation.The cells pre-processing are divided into two parts: one is Ras inhibitor (FTI-277) on the role of mononuclear cells, the other is p38 inhibitor (SB203580) on the role of mononuclear cells. Each split into two, then measure the phospho-p38 and NF-κB semi-quantitative by immunoblotting (Western blot) methods after 30 minute.Results: the first part: (1) The expressions of p38 and NF-κB of FKN group is increased compared with the control group; (2) The expressions of p38 and NF-κB of FKN+FTI-277(Ras inhibitor) group are decreased compared with the FKN group. The second Part: (1) The expressions of p38 and NF-κB of FKN group is increased compared with the control group; (2) The expressions of p38 and NF-κB of FKN+SB203580 (p38 inhibitor) group are decreased compared with the FKN group.Conclusions: (1) FKN increases the expression of NF-κB in peripheral blood monocyte as one of the mechanism of contributing to the progression of atherosclerosis; (2) FKN decreases the expression of phosphor-p38 in peripheral blood monocyte; (3) Ras is involved in NF-κB activation of human PBMC induced by FKN. (4) p38 is involved in NF-κB activation of human PBMC induced by FKN. (5) The Ras/p38 pathway is one signal transduction circuit by which FKN induce NF-κB activate.