.1. Induced By Pma In Hl-60 Cell Differentiation Process Of Tlr2 And Tlr4 And Cd14 Expression Kinetics Study. Murine Macrophage Heat Shock Response By The Ikba / Nf-kb Signaling Pathway Inhibits Lps-induced Interleukin-12 Expression,

1. Innate immunity and Toll-like receptorsThe innate immunity provides the first line of host defense response against microbes. Innate immunity is also the oldest mechanism of defense against microbes with new perspective and is present in all multicellular organisms, including plants and insects. Macrophages play central roles in innate immunity and are an important bridge between innate and adaptive immunity. Macrophages not only play a key role in recognition and elimination of pathogens, but also are a kind of essential antigen presenting cells in regulating adaptive immune response through cytokine and costimulatory molecules. Toll-like receptors are the eyes of innate immunity. Here, after a brief introduction of innate immunity, we reviewed the biological functions of Toll-like receptors, and also described our findings in the expression patterns of TLR2 and TLR4 during myeloid leukemia cell differentiation. We found that the expression of TLR2 and CD14 mRNA was increased after treatment by 10 nM PMA for 24 h. However, VitD3 only induced expression of CD14 but not TLR2 in HL-60 cells. TLR 4 was expressed constitutively before differentiation and increased slightly after that. Furthermore, up-regulation of TLR2 and CD14 mRNA expression by PMA was abrogated by a protein kinase C inhibitor, Calphostin C, suggesting the up-regulation of TLR2 and CD14 mRNA is dependent on the activation of PKC. 2. Stress, NF-?B and IL-12 Stress molecular biology is one of the burning subjects in the modern biological sciences. Although this subject has been historically interested in, the fundamental task is still to enhance the knowledge of and to promote research on the responses mounted by all living cells and organisms to environmental, physiological, and pathological stress. The cellular reponses is evolutionarily conserved in all living cells and organisms, and a major role is attributed to the induced heat shock proteins (HSPs). The HSPs are alsocalled stress protein[1]. In general, there are several classed of HSPs categorized according to their apparent subunit molecular weights, including a small Hsp family with molecular masses ranging from 14 kDa to 29 kDa, Hsp40 family, Hsp60 family, Hsp 70 family, Hsp90 family and Hsp110 family. Among them, Hsp70 family is the most discussed and characterized. NF??B/Rel is a family of transcription factors composed of homodimers or heterodimers of proteins homologous to the c-Rel protein. NF??B factors are important in the transcription of many genes in both innate and adaptive immune response[2-4].IL-12 is an important cytokine secreted by monocytes/macrophages through the transduction of TLRs in response to pathogens. It can induce production of IFN-? in NK cells and activated T cells as well as activation of monocytes/macrophages against infectious microbes and tumor. In addition, IFN-??can enhance the function of NK and CTL cells and promote the development of Th1 cells in adaptive immunity. Thus, IL-12 is a crucial bridge between innate and adaptive immunity.Based on the development of above subjects and our original research work, we report the effect of heat shock on lipopolysaccharide (LPS)-induced IL?12 expression. The augmentation of LPS-induced IL?12 p40 mRNA and p70 protein was significantly suppressed in both murine peritoneal macrophages and mice macrophage cell-line RAW264.7 after heat shock. The binding activity of NF-?B was reduced by prior heat shock. LPS did not induce degradation of the inhibitory protein I?B? in heat-shocked cells, which might be a potential mechanism to block NF-?B activation. Furthermore, transient transfection assay in RAW264.7 cells demonstrated that LPS-induced activation of delete-mutated IL-12 p40 promoter DM703 and DM138 (both contain NF-?B motif) was highly sensitive to heat shock. These data suggest that heat shock influences expression of IL-12 through I?B?/NF-?B pathway.