Pattern recognition receptors （PRRs） and their signaling pathways have essential roles in recognizing various components of pathogens as well as damaged cells and triggering inflammatory responses that eliminate inv...Pattern recognition receptors （PRRs） and their signaling pathways have essential roles in recognizing various components of pathogens as well as damaged cells and triggering inflammatory responses that eliminate invading microorganisms and damaged cells. The zebrafish relies heavily on these primary defense mechanisms against pathogens. Here, we review the major PRR signaling pathways in the zebrafish innate immune system and compare these signaling pathways in zebrafish and humans to reveal their evolutionary relationship and better understand their innate immune defense mechanisms.展开更多
Toll-like receptors (TLRs) are found on the membranes of pattern recognition receptors and not only play important roles in activating immune responses but are also involved in the pathogenesis of inflammatory disease...Toll-like receptors (TLRs) are found on the membranes of pattern recognition receptors and not only play important roles in activating immune responses but are also involved in the pathogenesis of inflammatory disease, injury and cancer. Furthermore, TLRs are also able to recognize endogenous alarmins released by damaged tissue and necrosis and/or apoptotic cells and are present in numerous autoimmune diseases. Therefore, the release of endogenous TLR ligands plays an important role in initiating and driving inflammatory diseases. Increasing data suggest a role for TLR signaling in rheumatoid arthritis, which is an autoimmune disease. Although their involvement is not comprehensively understood, the TLRs signaling transducers may provide potential therapeutic targets.展开更多
Background Trichophyton rubrum （T. rubrum） represents the most important agent of dermatophytosis in humans. T. rubrum infection causes slight inflammation, and tends to be chronic and recurrent. It is suggested tha...Background Trichophyton rubrum （T. rubrum） represents the most important agent of dermatophytosis in humans. T. rubrum infection causes slight inflammation, and tends to be chronic and recurrent. It is suggested that it may result from the failure of epithelial cells to recognize T. rubrum effectively and initiate effective immune responses. The C-type lectin receptors （CLR） and toll-like receptors （TLR） are the two major pattern recognition receptors （PRRs） that recognize fungal components. Therefore, the purpose of the study was to analyze the expression of those PRRs and the cytokines in HaCaT cells stimulated with heat-inactivated T. rubrum conidia and hyphae, respectively. Methods HaCaT cells were unstimulated or stimulated with heat-inactivated T. rubrum conidia and hyphae （l×106 and 1.5×105 colony-forming unit （CFU） in 2 ml medium, respectively） for 6, 12 and 24 hours. The mRNA expression of PRRs involved in recognizing fungal pathogen-associated molecular patterns （PAMPs） and signaling molecules were measured by quantitative reverse transcription polymerase chain reaction （RT-PCR）. Meanwhile, surface toll-like receptor （TLR） 2, TLR4 and Dectin-1 were analyzed by fluorescence-activated cell sorter （FACS） 24 hours after treatment. The cytokines were detected in cell culture supernatants of HaCaT cells in 12 and 24 hours after treatment. Results HaCaT cells constitutively expressed mRNA of membrane-bound TLR1,2, 4 and 6, Dectinl and DC-SIGN, but not Dectin-2 or Mincle. Heat-killed T. rubrum did not significantly upregulate gene transcriptions of the PRRs of HaCaT cells. Heat-inactivated T. rubrum conidia significantly reduced the surface expression of TLR2 and Dectin-1, and suppressed the secretions of interferon-inducible protein-10 （IP-10） and monocyte chemotactic protein-1 （MCP-1） of HaCaT cells, while heat-killed T. rubrum hyphae significantly induced the secretions of IP-10 and MCP-I. Conclusion The cell-wall antigens of T. rubrum fail to activate transc展开更多
Background： Trichophyton rubrum is superficial fungi characteristically confined to dead keratinized tissues. These observations suggest that the soluble components released by the fungus could influence the host imm...Background： Trichophyton rubrum is superficial fungi characteristically confined to dead keratinized tissues. These observations suggest that the soluble components released by the fungus could influence the host immune response in a cell in contact-free manner. Therefore, this research aimed to analyze whether the culture supernatant derived from T. rubrum grown in the nail medium could elicit the immune response of keratinocyte effectively. Methods： The culture supernatants of two strains （T1a, TXHB） were compared for the β-glucan concentrations and their capacity to impact the innate immunity of keratinocytes. The β-glucan concentrations in the supernatants were determined with the fungal G-test kit and protein concentrations with bicinchoninic acid protein quantitative method, then HaCaT was stimulated with different concentrations of culture supernatants by adopting morphological method to select a suitable dosage. Expressions of host defense genes were assessed by quantitative polymerase chain reaction after the HaCaT was stimulated with the culture supernatants. Data were analyzed with one-way analysis of variance, followed by the least significant difference test. Results： The T. rubrum strains （T1a and TXHB） released β-glucan of 87.530 ± 37.581 pg/ml and 15.747 ± 6.453 pg/ml, respectively into the media. The messenger RNA （mRNA） expressions of toll-like receptor-2 （TLR2）, TLR4, and CARD9 were moderately up-regulated in HaCaT within 6-h applications of both supernatants. HaCaT cells were more responsive to Tla than TXHB. The slight increase of dendritic cells-specific intercellular adhesion molecule 3-grabbing nonintegrin expression was faster and stronger, induced by T1a supematant than TXHB. The moderate decreases of RNase 7, the slight up-regulations of Dectin-1 and interleukin-8 at the mRNA level were detected only in response to T la rather than TXHB After a long-time contact, all the elevated defense genes decreased alter 24 h. Conclusion： The culture supernatant of T. r展开更多
Melanization in insect hemolymph is triggered by the recognition of pathogen-associated molecular patterns via pattern recognition receptors. The signal transduction leads to the activation of the prophenoloxidase and...Melanization in insect hemolymph is triggered by the recognition of pathogen-associated molecular patterns via pattern recognition receptors. The signal transduction leads to the activation of the prophenoloxidase and hence the generation of melanin. The proPO activation process must be tightly controlled to minimize the host damage caused by reactive intermediates during melanin synthesis. The full-length cDNA sequence of a 20 kDa hemolymph protein from Bombyx (Bmhp20) was determined. Bmhp20 gene was expressed in larval fat body, integument, trachea, and ovary and was induced by the challenge of B. bombyseptieus. Binding of recombinant Bmhp20 to microbial cell wall components as well as gram-positive bacteria and fungi was confirmed. Phenoloxidase activity assay indicated that recombinant Bmhp20 blocked the proPO activation in hemolymph that was triggered by peptidoglycan or beta-1, 3-glucan. Our data suggest that Bmhp20 plays bifunctional roles in silkworm humoral responses: to participate in pattern recognition and to block the activation of proPO.展开更多
Liver is a site of viral replication and liver dysfunction is a characteristic of severe dengue infection. To understand these mechanisms, we analyzed the response of a hepatic cell linage, HepG2 to infection with den...Liver is a site of viral replication and liver dysfunction is a characteristic of severe dengue infection. To understand these mechanisms, we analyzed the response of a hepatic cell linage, HepG2 to infection with dengue 3 virus (strain 16562). Steady state levels of mRNA accumulation were assessed for 14 genes involved in modulation of the host immune responses, at 6, 24 and 48 hpi, by quantitative reverse transcription real-time PCR (qRT-PCR). Fourteen genes showed altered expression upon infection with D3V including;cytokines/chemokines (IL-1β, IL-6, IL-8, RANTES, MCP-2, IL-2Rα and TGF-βIIIR), type I interferon (IFN-α and IFN-β), and pattern-recognition receptors (TLR3, TLR8, RIG-1, MDA5 and MyD88). Although these genes are associated with mechanism of innate immune response and anti-viral activity, their altered expression does not inhibit D3V (strain 16562) growth kinetics and virus yield in HepG2 cells. Gene expression in liver may explain pathological changes associated with dengue virus infection.展开更多
基金ACKNOWLEDGEMENTS TJ is supported by the Fundamental Research Funds for the Central Universities and the 100 Talents Program of the Chinese Academy of Sciences. YIL is supported by the China Postdoctoral Science Foundation. We express our appreciation to Tsan Sam Xiao at Case Western Reserve University and Bin Lin at the National Institute of Allergy and Infectious Diseases, National Institutes of Health, USA for proofreading and suggestions.
文摘Pattern recognition receptors （PRRs） and their signaling pathways have essential roles in recognizing various components of pathogens as well as damaged cells and triggering inflammatory responses that eliminate invading microorganisms and damaged cells. The zebrafish relies heavily on these primary defense mechanisms against pathogens. Here, we review the major PRR signaling pathways in the zebrafish innate immune system and compare these signaling pathways in zebrafish and humans to reveal their evolutionary relationship and better understand their innate immune defense mechanisms.
基金Supported by The National Natural Science Foundation of China (30871193, 30972748, 81001319)the Natural Science Foundation of Colleges and Universities in Jiangsu Province(Grant No. 09KJB310001)Innovation Fund for Candidate of Doctor in Jiangsu Province(Grant No.CX09B_217Z)
文摘Toll-like receptors (TLRs) are found on the membranes of pattern recognition receptors and not only play important roles in activating immune responses but are also involved in the pathogenesis of inflammatory disease, injury and cancer. Furthermore, TLRs are also able to recognize endogenous alarmins released by damaged tissue and necrosis and/or apoptotic cells and are present in numerous autoimmune diseases. Therefore, the release of endogenous TLR ligands plays an important role in initiating and driving inflammatory diseases. Increasing data suggest a role for TLR signaling in rheumatoid arthritis, which is an autoimmune disease. Although their involvement is not comprehensively understood, the TLRs signaling transducers may provide potential therapeutic targets.
基金This Work was supported by the grants from theFundamental Research Funds for the Central Universities （No. 10ykpy04） and the National Natural Science Foundation of China （No. 30600028）.
文摘Background Trichophyton rubrum （T. rubrum） represents the most important agent of dermatophytosis in humans. T. rubrum infection causes slight inflammation, and tends to be chronic and recurrent. It is suggested that it may result from the failure of epithelial cells to recognize T. rubrum effectively and initiate effective immune responses. The C-type lectin receptors （CLR） and toll-like receptors （TLR） are the two major pattern recognition receptors （PRRs） that recognize fungal components. Therefore, the purpose of the study was to analyze the expression of those PRRs and the cytokines in HaCaT cells stimulated with heat-inactivated T. rubrum conidia and hyphae, respectively. Methods HaCaT cells were unstimulated or stimulated with heat-inactivated T. rubrum conidia and hyphae （l×106 and 1.5×105 colony-forming unit （CFU） in 2 ml medium, respectively） for 6, 12 and 24 hours. The mRNA expression of PRRs involved in recognizing fungal pathogen-associated molecular patterns （PAMPs） and signaling molecules were measured by quantitative reverse transcription polymerase chain reaction （RT-PCR）. Meanwhile, surface toll-like receptor （TLR） 2, TLR4 and Dectin-1 were analyzed by fluorescence-activated cell sorter （FACS） 24 hours after treatment. The cytokines were detected in cell culture supernatants of HaCaT cells in 12 and 24 hours after treatment. Results HaCaT cells constitutively expressed mRNA of membrane-bound TLR1,2, 4 and 6, Dectinl and DC-SIGN, but not Dectin-2 or Mincle. Heat-killed T. rubrum did not significantly upregulate gene transcriptions of the PRRs of HaCaT cells. Heat-inactivated T. rubrum conidia significantly reduced the surface expression of TLR2 and Dectin-1, and suppressed the secretions of interferon-inducible protein-10 （IP-10） and monocyte chemotactic protein-1 （MCP-1） of HaCaT cells, while heat-killed T. rubrum hyphae significantly induced the secretions of IP-10 and MCP-I. Conclusion The cell-wall antigens of T. rubrum fail to activate transc
文摘Background： Trichophyton rubrum is superficial fungi characteristically confined to dead keratinized tissues. These observations suggest that the soluble components released by the fungus could influence the host immune response in a cell in contact-free manner. Therefore, this research aimed to analyze whether the culture supernatant derived from T. rubrum grown in the nail medium could elicit the immune response of keratinocyte effectively. Methods： The culture supernatants of two strains （T1a, TXHB） were compared for the β-glucan concentrations and their capacity to impact the innate immunity of keratinocytes. The β-glucan concentrations in the supernatants were determined with the fungal G-test kit and protein concentrations with bicinchoninic acid protein quantitative method, then HaCaT was stimulated with different concentrations of culture supernatants by adopting morphological method to select a suitable dosage. Expressions of host defense genes were assessed by quantitative polymerase chain reaction after the HaCaT was stimulated with the culture supernatants. Data were analyzed with one-way analysis of variance, followed by the least significant difference test. Results： The T. rubrum strains （T1a and TXHB） released β-glucan of 87.530 ± 37.581 pg/ml and 15.747 ± 6.453 pg/ml, respectively into the media. The messenger RNA （mRNA） expressions of toll-like receptor-2 （TLR2）, TLR4, and CARD9 were moderately up-regulated in HaCaT within 6-h applications of both supernatants. HaCaT cells were more responsive to Tla than TXHB. The slight increase of dendritic cells-specific intercellular adhesion molecule 3-grabbing nonintegrin expression was faster and stronger, induced by T1a supematant than TXHB. The moderate decreases of RNase 7, the slight up-regulations of Dectin-1 and interleukin-8 at the mRNA level were detected only in response to T la rather than TXHB After a long-time contact, all the elevated defense genes decreased alter 24 h. Conclusion： The culture supernatant of T. r
文摘Melanization in insect hemolymph is triggered by the recognition of pathogen-associated molecular patterns via pattern recognition receptors. The signal transduction leads to the activation of the prophenoloxidase and hence the generation of melanin. The proPO activation process must be tightly controlled to minimize the host damage caused by reactive intermediates during melanin synthesis. The full-length cDNA sequence of a 20 kDa hemolymph protein from Bombyx (Bmhp20) was determined. Bmhp20 gene was expressed in larval fat body, integument, trachea, and ovary and was induced by the challenge of B. bombyseptieus. Binding of recombinant Bmhp20 to microbial cell wall components as well as gram-positive bacteria and fungi was confirmed. Phenoloxidase activity assay indicated that recombinant Bmhp20 blocked the proPO activation in hemolymph that was triggered by peptidoglycan or beta-1, 3-glucan. Our data suggest that Bmhp20 plays bifunctional roles in silkworm humoral responses: to participate in pattern recognition and to block the activation of proPO.
文摘Liver is a site of viral replication and liver dysfunction is a characteristic of severe dengue infection. To understand these mechanisms, we analyzed the response of a hepatic cell linage, HepG2 to infection with dengue 3 virus (strain 16562). Steady state levels of mRNA accumulation were assessed for 14 genes involved in modulation of the host immune responses, at 6, 24 and 48 hpi, by quantitative reverse transcription real-time PCR (qRT-PCR). Fourteen genes showed altered expression upon infection with D3V including;cytokines/chemokines (IL-1β, IL-6, IL-8, RANTES, MCP-2, IL-2Rα and TGF-βIIIR), type I interferon (IFN-α and IFN-β), and pattern-recognition receptors (TLR3, TLR8, RIG-1, MDA5 and MyD88). Although these genes are associated with mechanism of innate immune response and anti-viral activity, their altered expression does not inhibit D3V (strain 16562) growth kinetics and virus yield in HepG2 cells. Gene expression in liver may explain pathological changes associated with dengue virus infection.
