Search results for "TLR2"
showing 10 items of 57 documents
The Gut Microbiota as an Influencing Factor of Arterial Thrombosis
2018
The mutualistic gut microbiota does not only impact the development and function of various immune cell types, but it also influences the function of the hepatic vascular endothelium and prothrombotic platelet function. With germ-free mouse models, we have demonstrated that gut-derived microbial-associated molecular patterns could stimulate hepatic von Willebrand factor (VWF) synthesis and plasmatic VWF levels through Toll-like receptor-2 (TLR2), thus defining the extent of platelet deposition to the subendothelial matrix of the ligation-injured common carotid artery. In addition to the microbiota-derived choline metabolite trimethylamine N-oxide and the microbiota's regulatory role on the …
TLR2 and Dectin-1 Signaling in Mouse Hematopoietic Stem and Progenitor Cells Impacts the Ability of the Antigen Presenting Cells They Produce to Acti…
2020
Microbial recognition by pattern recognition receptors (PRRs) expressed on hematopoietic stem and progenitor cells (HSPCs) not only activates myelopoiesis but also programs the function of the monocytes and macrophages they produce. For instance, changes in HSPC programming modify the ability of macrophages derived from them to produce inflammatory cytokines. While HSPCs exposed to a TLR2 agonist give rise to tolerized macrophages (lower proinflammatory cytokine production), HSPCs treated with Dectin-1 ligands produce trained macrophages (higher proinflammatory cytokine production). However, nothing is known about the impact of HSPC exposure to microbes on the function of antigen presenting…
Toll-like receptor 3 mediates expression of clusterin/apolipoprotein J in vascular smooth muscle cells stimulated with RNA released from necrotic cel…
2010
Clusterin/Apolipoprotein J is a protein that is upregulated in a broad spectrum of diverse pathological processes. The predominant form is a secreted glycoprotein (sCLU) with cytoprotective and anti-inflammatory properties which shows enhanced expression in vascular smooth muscle cells (VSMC) following aortic injury and in atherosclerotic disease. Recent evidence indicates that during atherosclerosis, Toll-like receptors (TLRs) are activated in vascular cells by endogenous ligands. Here, we analyzed whether CLU expression in VSMC is controlled by TLRs, and stimulated by factors associated with or released by necrotic cells. Activation of TLR3 by the synthetic RNA analogue polyinosinic-polyc…
Toll-like receptor 2 is dispensable for acquired host immune resistance to Candida albicans in a murine model of disseminated candidiasis
2004
Previous work by our group showed that Toll-like receptor 2 (TLR2) is essential for activation of innate immunity, playing a major role in the response of macrophages to Candida albicans, triggering cytokine and chemokine expression, and therefore TLR2 -/- mice are more susceptible to systemic primary candidiasis. In this work, we used a murine model of systemic C. albicans infection, in which resistance to reinfection with virulent wild-type cells is induced by prior exposure of mice to a low-virulence agerminative strain of C. albicans (primary sublethal infection), to study the influence of TLR2 gene deletion on (i) the ability to develop an acquired resistance upon vaccination; (ii) the…
Characterization of PAMP/PRR interactions in European eel (Anguilla anguilla) macrophage-like primary cell cultures
2013
The eel (Anguilla anguilla) has been identified as a vulnerable species with stocks dramatically declining over the past decade. In an effort to support the species from overfishing of wild stocks increased interest in eel aquaculture has been notable. In order to expand the scarce knowledge concerning the biology of this species significant research efforts are required in several fields of biology. The development of cell culture systems to study the immune response is a key step towards an increased understanding of the immune response and to develop resources to support further study in this threatened species. Macrophages are one of the most important effector cells of the innate immun…
Early steps in the European eel (Anguilla anguilla)–Vibrio vulnificus interaction in the gills: Role of the RtxA13 toxin
2015
Vibrio vulnificus is an aquatic gram-negative bacterium that causes a systemic disease in eels called warm-water vibriosis. Natural disease occurs via water born infection; bacteria attach to the gills (the main portal of entry) and spread to the internal organs through the bloodstream, provoking host death by haemorrhagic septicaemia. V.vulnificus produces a toxin called RtxA13 that hypothetically interferes with the eel immune system facilitating bacterial invasion and subsequent death by septic shock. The aim of this work was to study the early steps of warm-water vibriosis by analysing the expression of three marker mRNA transcripts related to pathogen recognition (tlr2 and tlr5) and in…
Direct Toll-Like Receptor-Mediated Stimulation of Hematopoietic Stem and Progenitor Cells Occurs In Vivo and Promotes Differentiation Toward Macropha…
2012
Abstract As Toll-like receptors (TLRs) are expressed by hematopoietic stem and progenitor cells (HSPCs), they may play a role in hematopoiesis in response to pathogens during infection. We show here that TLR2, TLR4, and TLR9 agonists (tripalmitoyl-S-glyceryl-L-Cys-Ser-(Lys)4 [Pam3CSK4], lipopolysaccharide [LPS], and CpG oligodeoxynucleotide [ODN]) induce the in vitro differentiation of purified murine lineage negative cells (Lin−) as well as HSPCs (identified as Lin− c-Kit+ Sca-1+ IL-7Rα− [LKS] cells) toward macrophages (Mph), through a myeloid differentiation factor 88 (MyD88)-dependent pathway. In order to investigate the possible direct interaction of soluble microorganism-associated mol…
Hypoallergenic fragment of Par j 2 increases functional expression of Toll-like receptors in atopic children.
2006
Background: Parietaria judaica (Par j) is one of the main causes of allergy in the Mediterranean countries. The activation of Toll-like receptor 4 (TLR4) by lipopolysaccharide (LPS) inhibits nasal inflammation of atopic children. Objective: To examine, in vivo and in vitro, the effect of recombinant Par j 2 (rPar j 2) and of its fragments (1–55 and 52–102) on atopic children. Methods: We used skin prick test for in vivo evaluations. We assessed, in vitro, in peripheral blood mononuclear cells (PBMC), the effect of rPar j 2 and of the two fragments on neutrophil chemotaxis, on CD45RO, on TLR2 and TLR4 expression, on LPS binding and on interferon (IFN)-γ release, by a microchemotaxis chambe…
TLR2, but not TLR4, triggers cytokine production by murine cells in response to Candida albicans yeasts and hyphae.
2006
Toll-like receptors (TLRs) function as sensors for infection that induce the activation of the immune responses. Recent studies have demonstrated a crucial involvement of TLRs in the recognition of fungal pathogens such as Candida albicans. Although both TLR2 and TLR4 have been implicated in the host interaction with C. albicans, their specific role during infection has not been unequivocally established, as conflicting results have been reported. In this review, we summarize and discuss our own and others' key findings about the specific role of TLR2 and TLR4 in murine resistance to candidiasis, and in triggering cytokine secretion by murine cells in response to C. albicans yeasts and hyph…
Candida albicansstimulatesin vivodifferentiation of haematopoietic stem and progenitor cells towards macrophages by a TLR2-dependent signalling
2013
Toll-like receptors (TLRs) are expressed by haematopoietic stem and progenitor cells (HSPCs), and may play a role in haematopoiesis in response to pathogens during infection. We have previously demonstrated that (i) inactivated yeasts of Candida albicans induce in vitro differentiation of HSPCs towards the myeloid lineage, and (ii) soluble TLR agonists induce in vivo their differentiation towards macrophages. In this work, using an in vivo model of HSPCs transplantation, we report for the first time that HSPCs sense C. albicans in vivo and subsequently are directed to produce macrophages by a TLR2-dependent signalling. Purified lineage-negative cells (Lin(-)) from bone marrow of C57BL/6 mic…