ABSTRACT
<p><b>OBJECTIVE</b>To investigate whether Candida albicans-native phospholipomannan (PLM) induce an inflammation response through Toll-like receptor(TLRé2 in human acute monocytic leukemia cell line (THP-1) cells.</p><p><b>METHODS</b>Human THP-1 monocytes were challenged with PLM in vitro. The mRNA expressions of TLR2, TLR4, proinflammatory cytokine [interleukin(IL)-6], and chemokine (IL-8) were assayed by real time reverse transcription polymerase chain reaction. The secretions of IL-6 and IL-8 were measured by enzyme-linked immunosorbent assay. The expression of TLR2 was analyzed with Western blot.</p><p><b>RESULTS</b>PLM increased the mRNA expressions and secretions of proinflammatory cytokines (IL-6) and chemokines (IL-8) in THP-1 cells (all P=0.0000). PLM up-regulated the mRNA and protein levels of TLR2 (P=0.0000), whereas the mRNA level of TLR4 was not altered. PLM hydrolyzed with β-D-mannoside manno hydrolase failed to induce gene and protein expressions of TLR2, IL-6, and IL-8. Anti-TLRS-neutralizing antibody blocked the PLM-induced secretions of IL-6 and IL-8 in THP-1 cells (P = 0.0003, P = 0.0010).</p><p><b>CONCLUSION</b>Canidada albicans-native PLM may contribute to the inflammatory responses during Candida infection in a TLR2-dependent manner.</p>
Subject(s)
Humans , Candida albicans , Chemistry , Cells, Cultured , Glycolipids , Pharmacology , Interleukin-6 , Metabolism , Interleukin-8 , Metabolism , Monocytes , Allergy and Immunology , Metabolism , Toll-Like Receptor 2 , Metabolism , Toll-Like Receptor 4 , MetabolismABSTRACT
<p><b>BACKGROUND</b>beta-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 beta-glucan and induce immune responses. In this study, we sought to clarify whether insoluble beta-glucan from the cell wall of C. albicans (CaIG) could induce immune responses in human THP-1 monocytes (a human acute monocytic leukemia cell line) and to determine the underlying mechanisms.</p><p><b>METHODS</b>Human THP-1 monocytes were challenged with CaIG in vitro. The mRNA expression of Dectin-1, Toll-like receptors (TLR2), proinflammatory cytokine (TNF-alpha) 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). H(2)O(2) release was determined by microplate fluorescent assay. Western blotting was used to analyze IkappaB-a phosphorylation and degradation.</p><p><b>RESULTS</b>Exposure of THP-1 monocytes to CaIG led to increased gene expression and secretion of TNF-alpha and IL-8. CaIG induced H(2)O(2) release in a time-dependent manner. CaIG hydrolyzed with zymolyase failed to induce gene expression and secretion of TNF-alpha, IL-8 and H(2)O(2) release. CaIG up-regulated the mRNA of Dectin-1, whereas the mRNA level of TLR2 was not altered. THP-1 monocytes challenged with CaIG resulted in the activation of NF-kappaB in a time-dependent manner. Dectin-1 inhibitor laminarin blocked the CaIG-induced production of TNF-alpha and H(2)O(2) in THP-1 monocytes, but no such effect was observed in pretreatment with anti-TLR2 neutralizing antibody and the LPS inhibitor (polymyxin B).</p><p><b>CONCLUSION</b>CaIG may play a role in activation of immune responses in human THP-1 cells through Dectin-1, not TLR2.</p>
Subject(s)
Humans , Blotting, Western , Candida albicans , Metabolism , Cell Line, Tumor , Cell Wall , Metabolism , Enzyme-Linked Immunosorbent Assay , Gene Expression , Hydrogen Peroxide , Metabolism , Interleukin-8 , Genetics , Metabolism , Lectins, C-Type , Membrane Proteins , Genetics , Metabolism , Monocytes , Allergy and Immunology , Metabolism , Nerve Tissue Proteins , Genetics , Metabolism , Reverse Transcriptase Polymerase Chain Reaction , Toll-Like Receptor 2 , Genetics , Tumor Necrosis Factor-alpha , Genetics , Metabolism , beta-Glucans , PharmacologyABSTRACT
<p><b>OBJECTIVE</b>To investigate the toll-like receptors (TLR) profile of human epidermal keratinocytes.</p><p><b>METHODS</b>We cultured the immortalized human epidermal keratinocyte cell line HaCaT cells and normal human epidermal keratinocytes (NHEK) and separated epidermis with dispase from foreskins. TLR 1-10 mRNA expression was detected with reverse transcription polymerase chain reaction (RT-PCR). TLR 2 and 4 protein expressions on surface of HaCaT cells and NHEK were detected using flow cytometry.</p><p><b>RESULTS</b>HaCaT cells, NHEK, and epidermis all expressed TLR 1-10 mRNA with different intensity. TLR 4 protein was detected on the surfaces of HaCaT cells and NHEK, while the expression of TLR 2 protein was few.</p><p><b>CONCLUSION</b>Human epidermal keratinocytes constitutively express all TLR 1-10 mRNA, which may enable human keratinocytes to respond to a wide range of pathogenic micro-organisms.</p>