Innate immune surveillance in the blood is executed mostly by circulating monocytes, which recognize conserved bacterial molecules such as peptidoglycan and lipopolysaccharide. Toll-like receptors (TLR) play a central role in microbe-associated molecular pattern detection. The aim of this study was to compare the differences in TLR expression and cytokine production after stimulation of peripheral blood cells with heat-killed gram-negative and gram-positive human pathogens: Neisseria meningitidis, Escherichia coli, Staphylococcus aureus, and Streptococcus pneumoniae. We found that TLR2 expression is up-regulated on monocytes after stimulation with S. aureus, S. pneumoniae, E. coli, and N. meningitidis. Moreover, TLR2 up-regulation was positively associated with increasing concentrations of gram-positive bacteria, whereas higher concentrations of gram-negative bacteria, especially E. coli, caused a milder TLR2 expression increase when compared to low doses. Cytokines were produced in similar dose-dependent profiles regardless of the stimulatory pathogen; however, gram-negative pathogens induced higher cytokine levels when compared to gram-positive bacteria at the same density. These results indicate that gram-positive and gram-negative bacteria differ in their dose-dependent patterns of induction of TLR2 and TLR4, but not cytokine expression.

• MeSH
• cytokiny sekrece   MeSH
• gramnegativní bakterie imunologie   MeSH
• grampozitivní bakterie imunologie   MeSH
• kultivované buňky MeSH
• leukocyty mononukleární imunologie   MeSH
• lidé MeSH
• toll-like receptor 2 biosyntéza   MeSH
• toll-like receptor 4 biosyntéza   MeSH
• vysoká teplota MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Innate immune surveillance in the blood is executed mostly by circulating monocytes, which recognise conserved bacterial molecules such as peptidoglycan and lipopolysaccharide. Toll-like receptors (TLR) play a central role in microbe-associated molecular pattern detection. Here, we compared the differences in TLR expression and cytokine production after stimulation of peripheral blood cells with heat-killed Gram-negative and Gram-positive human pathogens Neisseria meningitidis, Escherichia coli, Staphylococcus aureus and Streptococcus pneumoniae. We found that TLR2 expression is up-regulated on monocytes after stimulation with S. aureus, S. pneumoniae, E. coli and N. meningitidis. Moreover, TLR2 up-regulation was positively associated with increasing concentrations of Gram-positive bacteria, whereas higher concentrations of Gram-negative bacteria, especially E. coli, caused a milder TLR2 expression increase compared with low doses. Cytokines were produced in similar dose-dependent profiles regardless of the stimulatory pathogen; however, Gram-negative pathogens induced higher cytokine levels than Gram-positive ones at same concentrations. These results indicate that Gram-positive and Gram-negative bacteria differ in their dose-dependent patterns of induction of TLR2 and TLR4, but not in cytokine expression.

• MeSH
• aktivace transkripce MeSH
• cytokiny biosyntéza   MeSH
• gramnegativní bakterie genetika   imunologie   MeSH
• grampozitivní bakterie genetika   imunologie   MeSH
• lidé MeSH
• monocyty imunologie   MeSH
• přirozená imunita MeSH
• regulace genové exprese MeSH
• signální transdukce imunologie   MeSH
• toll-like receptor 2 biosyntéza   genetika   imunologie   MeSH
• toll-like receptor 4 biosyntéza   genetika   imunologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Dysregulation of innate and adaptive intestinal immune responses to bacterial microbiota is supposed to be involved in pathogenetic mechanisms of inflammatory bowel diseases (IBDs). We investigated expression of Toll-like receptor 2 (TLR2), TLR4, and their transmembrane coreceptor CD14 in biopsy samples from patients with IBD and in non-inflamed gut mucosa from controls. Small intestine and colon samples were obtained by colonoscopy from patients with Crohn's disease (CD), ulcerative colitis (UC), and controls. Immunohistochemical analysis of cryostat sections using polyclonal and monoclonal antibodies specific for TLR2, TLR4, and CD14 showed a significant increase in TLR2 expression in the terminal ileum of patients with inactive and active UC against controls. Significant upregulation of TLR4 expression relative to controls was found in the terminal ileum and rectum of UC patients in remission and in the terminal ileum of CD patients with active disease. CD14 expression was upregulated in the terminal ileum of CD patients in remission and with active disease, in the cecum of UC patients in remission and with active disease, and in rectum of UC patients with active disease. Hence, dysregulation of TLR2, TLR4, and CD14 expression in different parts of the intestinal mucosa may be crucial in IBD pathogenesis.

• MeSH
• antigeny CD14 biosyntéza   MeSH
• biopsie MeSH
• cékum metabolismus   patologie   MeSH
• Crohnova nemoc metabolismus   patologie   MeSH
• financování organizované MeSH
• ileum metabolismus   patologie   MeSH
• imunohistochemie MeSH
• lidé MeSH
• rektum metabolismus   patologie   MeSH
• střevní sliznice metabolismus   patologie   MeSH
• toll-like receptor 2 biosyntéza   MeSH
• toll-like receptor 4 biosyntéza   MeSH
• ulcerózní kolitida metabolismus   patologie   MeSH
• Check Tag
• lidé MeSH

Toll-like receptors (TLR) are key components of innate immune system. As TLR activation could induce potentially harmful inflammatory response, activation of TLR signaling pathways has to be under tight control. Besides other control mechanisms, an inhibitory function of murine TLR4 splice variants was recently demonstrated. In this study we investigated expression of four TLR4 splice variants in human antigen presenting cells (APC). Furthermore, we studied modification in TLR4 splice variants expression in APC in cystic fibrosis (CF) patients chronically infected by Gram-negative bacteria. We developed a novel reliable real-time PCR detection system that allowed monitoring of individual TLR4 splice variants expression. In APC from healthy donors we detected a characteristic transient increase of two out of four splice variants after lipopolysaccharide (LPS) stimulation. Similarly to murine TLR4, one of these variants, NM 003266, might translate to a potentially inhibitory protein. In contrast to controls, CF monocytes had significantly changed LPS-induced expression of TLR4 gene and its variants including reduced ability to up-regulate the expression of the potentially inhibitory variant upon stimulation. In accordance with this observation, monocytes from CF patients produced significantly more tumor necrosis factor after LPS stimulation than healthy controls. Our results thus describe the kinetics of TLR4 splicing variants expression after LPS stimulation and indicate a possible alteration of its regulation in CF patients.

• MeSH
• alternativní sestřih MeSH
• antigen prezentující buňky chemie   imunologie   MeSH
• cystická fibróza imunologie   MeSH
• dendritické buňky imunologie   MeSH
• dospělí MeSH
• financování organizované MeSH
• kultivované buňky MeSH
• lidé MeSH
• lipopolysacharidy imunologie   MeSH
• messenger RNA analýza   MeSH
• monocyty imunologie   MeSH
• polymerázová řetězová reakce s reverzní transkripcí metody   MeSH
• regulace genové exprese MeSH
• stanovení celkové genové exprese MeSH
• TNF-alfa biosyntéza   MeSH
• toll-like receptor 4 biosyntéza   genetika   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH