Background β-glucan is the major structure component of Candida albicans （C. albicans） cell wall. It has been demonstrated that Dectin-1 as the principal C-type lectin pattern-recognition receptor （PRR） can recog...Background β-glucan is the major structure component of Candida albicans （C. albicans） cell wall. It has been demonstrated that Dectin-1 as the principal C-type lectin pattern-recognition receptor （PRR） can recognize fungal β-glucan and induce immune responses. In this study, we sought to clarify whether insoluble β-glucan from the cell wall of C. albicans （CalG） could induce immune responses in human THP-1 monocytes （a human acute monocytic leukemia cell line） and to determine the underlying mechanisms. Methods Human THP-1 monocytes were challenged with CalG in vitro. The mRNA expression of Dectin-1, Toll-like receptors （TLR2）, proinflammatory cytokine （TNF-a） and chemokine （IL-8） was assayed by real-time reverse transcription polymerase chain reaction （RT-PCR）. The secretion of TNF-a and IL-8 were measured by enzyme-linked immunosorbent assay （ELISA）. H2O2 release was determined by microplate fluorescent assay. Western blotting was used to analyze IKB-a phosphorylation and degradation. Results Exposure of THP-1 monocytes to CalG led to increased gene expression and secretion of TNF-a and IL-8. CalG induced H2O2 release in a time-dependent manner. CalG hydrolyzed with zymolyase failed to induce gene expression and secretion of TNF-a, IL-8 and H2O2 release. CalG up-regulated the mRNA of Dectin-1, whereas the mRNA level of TLR2 was not altered. THP-1 monocytes challenged with CalG resulted in the activation of NF-KB in a time-dependent manner. Dectin-1 inhibitor laminarin blocked the CalG-induced production of TNF-a and H2O2 in THP-1 monocytes, but no such effect was observed in pretreatment with anti-TLR2 neutralizing antibody and the LPS inhibitor （polymyxin B）. Conclusion CalG may play a role in activation of immune responses in human THP-1 cells throuah Dectin-1, not TLR2.展开更多
基金This work was supported by a grant from National Natural Science Foundation of China （No. 30671893）.
文摘Background β-glucan is the major structure component of Candida albicans （C. albicans） cell wall. It has been demonstrated that Dectin-1 as the principal C-type lectin pattern-recognition receptor （PRR） can recognize fungal β-glucan and induce immune responses. In this study, we sought to clarify whether insoluble β-glucan from the cell wall of C. albicans （CalG） could induce immune responses in human THP-1 monocytes （a human acute monocytic leukemia cell line） and to determine the underlying mechanisms. Methods Human THP-1 monocytes were challenged with CalG in vitro. The mRNA expression of Dectin-1, Toll-like receptors （TLR2）, proinflammatory cytokine （TNF-a） and chemokine （IL-8） was assayed by real-time reverse transcription polymerase chain reaction （RT-PCR）. The secretion of TNF-a and IL-8 were measured by enzyme-linked immunosorbent assay （ELISA）. H2O2 release was determined by microplate fluorescent assay. Western blotting was used to analyze IKB-a phosphorylation and degradation. Results Exposure of THP-1 monocytes to CalG led to increased gene expression and secretion of TNF-a and IL-8. CalG induced H2O2 release in a time-dependent manner. CalG hydrolyzed with zymolyase failed to induce gene expression and secretion of TNF-a, IL-8 and H2O2 release. CalG up-regulated the mRNA of Dectin-1, whereas the mRNA level of TLR2 was not altered. THP-1 monocytes challenged with CalG resulted in the activation of NF-KB in a time-dependent manner. Dectin-1 inhibitor laminarin blocked the CalG-induced production of TNF-a and H2O2 in THP-1 monocytes, but no such effect was observed in pretreatment with anti-TLR2 neutralizing antibody and the LPS inhibitor （polymyxin B）. Conclusion CalG may play a role in activation of immune responses in human THP-1 cells throuah Dectin-1, not TLR2.
