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Inflammation plays an important role in the pathophysiological process of ischemic stroke.This article elaborates the inflammatory response process after ischemic stroke in order to improve the understanding of the pathophysiological mechanisms of ischemic stroke.
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Objective To evaluate the recognition and uptake of transglutaminase 3 (TG3) by dendritic cell-specific intercellular adhesion molecule 3-grabbing nonintegrin (DC-SIGN) receptors on the membrane surface of DC-SIGN-transfected human embryonic kidney (HEK) 293T cells and monocytederived dendritic cells (MDDCs).Methods The eukaryotic expression vector pGCMV-enhanced green fluorescent protein (EGFP) containing DC-SIGN gene fragments was transfected into HEK293T cells to prepare DC-SIGN-EGFP-HEK293T cells by using liposome transfection method.CD14+ monocytes were isolated from peripheral blood samples by magnetic bead-based negative selection,and then were induced by granulocyte-macrophage colony stimulating factor (GM-CSF) and interleukin-4 (IL-4) to prepare MDDCs.Laser confocal microscopy and flow cytometry were performed to evaluate the recognition and uptake of TG3 protein by DC-SIGN receptors on the surface of HEK293T cells and MDDCs.MDDCs treated without Alexa Fluor 647 dye-tagged TG3 served as blank control group,and those treated with Alexa Fluor 647 dye alone served as negative control group.Results After co-culture with TG3 for 3 hours,laser confocal microscopy and flow cytometry both showed that TG3 could be recognized by and uptaken through DC-SIGN receptors into HEK293T cells and MDDCs.Flow cytometry also revealed that the binding of TG3 to MDDCs could be partially blocked by DC-SIGN blocking antibodies.Neither the negative control group nor the blank control group showed the recognition and binding of TG3 to HEK293T cells and MDDCs.Conclusion TG3 can serve as a kind of autoantigen to be recognized and bound by DC-SIGN receptors,followed by uptake by dendritic cells.
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As a global disease,hepatitis B still threatens human health.However,the pathogenesis of hepatitis caused by HBV remains unclear.The innate immune system in the liver can detect HBV infection and use every strategy to eliminate the virus.DNA recognition receptors play an important role in this process;they recognize tlBV DNA or pgRNA in cytoplasm or nucleus,activate innate immunity through various signaling pathways to produce inflammatory cytokines and interferon,and finally exert their antiviral effect.This article summarizes the DNA recognition receptors involved in inflammation induced by HBV and HBV clearance,elaborates on their detailed pathways,and discusses the issues regarding the role of DNA recognition receptors in liver innate immunity induced by HBV and related perspectives.
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As a global disease,hepatitis B still threatens human health.However,the pathogenesis of hepatitis caused by HBV remains unclear.The innate immune system in the liver can detect HBV infection and use every strategy to eliminate the virus.DNA recognition receptors play an important role in this process;they recognize tlBV DNA or pgRNA in cytoplasm or nucleus,activate innate immunity through various signaling pathways to produce inflammatory cytokines and interferon,and finally exert their antiviral effect.This article summarizes the DNA recognition receptors involved in inflammation induced by HBV and HBV clearance,elaborates on their detailed pathways,and discusses the issues regarding the role of DNA recognition receptors in liver innate immunity induced by HBV and related perspectives.
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Objective To establish a cell model expressing the Langerhans cell-specific C type lectin receptor Langerin in vitro.Methods The cDNA of Langerin was obtained by PCR and cloned into a eukauotic green fluorescent protein (EGFP) expression vector pEGFP-C 1 with EGFP located in the N terminal region of the Langerin gene.Then,the recombinant plasmid was transfected into a human embryonic kidney carcinoma cell line HEK293T.Subsequently,laser confocal microscopy was performed to observe the expression of EGFP-Langerin fusion protein,and flow cytometry to measure the expression of Langerin.Laser confocal microscopy was also conducted to visualize the recognition and endocytosis of dust mite antigen (nDer p 2) by Langerin.Results PCR and Western blot confirmed the successful transfection of HEK293T cells with the recombinant plasmid as well as the expression of Langerin in the transfected cells.As flow cytometry revealed,the expression level of Langerin in transfected HEK293T cells was increased by 43％ compared with untransfected cells.Laser confocal microscopy showed that green fluorescein-labeled Langerin was successfully expressed,and could bind to and endocytose the red fluorescein-labeled antigen nDer p 2.Conclusions The fusion protein EGFP-Langerin expressed in HEK293T cells showed the distribution characteristic of cell surface receptors,and could bind to and endocytose allergens.
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Immune and tissue cells usually express pattern-recognition receptors (PRRs) to detect viruses and other microorganisms, thereby inducing signal cascade amplification and host innate immune responses. Since PRRs have strain-specific substrates and mechanisms of recognition, the identification of PRRs and mechanisms of PRRs-mediated responses is highly challenging. Besides, the research on RLRs-mediated immune responses has become more popular in cellular immunology recently. Accumulating evidence shows that post-translation modifications, such as ubiquitination, deubiquitination and ISGylation, play an important role in regulating host innate immune responses. In parallel, these approaches may be used by viruses to evade PRRs-mediated responses or to actively subvert these pathways for their own benefit. It was identified that STING (also called MITA/MPYS/ERIS) plays an important role in RIG-Ⅰ-like receptor(RLR) signaling as a type Ⅰ IFN stimulator, providing a special method for the research on complex host antiviral innate immune responses.