Search results for "tlr2"

The Involvement of Toll-like Receptor-2 in Arterial Thrombus Formation.

2018

There is emerging evidence for the participation of toll-like receptor-2 (TLR2) expressed on platelets and endothelial cells in the setting of arterial thrombosis. In isolated human platelets, TLR2/1 activation was demonstrated to induce platelet activation, secretion, aggregation, adhesion to collagen coatings and the formation of platelet-leukocyte conjugates, whereas murine platelets were less sensitive to TLR2/1 stimulation. Also, endothelial cells can be activated by stimulation with TLR2 agonists, resulting in increased expression of adhesion molecules, synthesis of inflammatory mediators and Weibel-Palade body exocytosis. Endothelial TLR2 signalling promotes atherosclerotic lesion de…

Gut microbiota regulate hepatic von Willebrand factor synthesis and arterial thrombus formation via Toll-like receptor-2.

2016

The symbiotic gut microbiota play pivotal roles in host physiology and the development of cardiovascular diseases, but the microbiota-triggered pattern recognition signaling mechanisms that impact thrombosis are poorly defined. In this article, we show that germ-free (GF) and Toll-like receptor-2 (Tlr2)-deficient mice have reduced thrombus growth after carotid artery injury relative to conventionally raised controls. GF Tlr2-/- and wild-type (WT) mice were indistinguishable, but colonization with microbiota restored a significant difference in thrombus growth between the genotypes. We identify reduced plasma levels of von Willebrand factor (VWF) and reduced VWF synthesis, specifically in he…

DNA Damage Signaling Instructs Polyploid Macrophage Fate in Granulomas.

2018

Granulomas are immune cell aggregates formed in response to persistent inflammatory stimuli. Granuloma macrophage subsets are diverse and carry varying copy numbers of their genomic information. The molecular programs that control the differentiation of such macrophage populations in response to a chronic stimulus, though critical for disease outcome, have not been defined. Here, we delineate a macrophage differentiation pathway by which a persistent Toll-like receptor (TLR) 2 signal instructs polyploid macrophage fate by inducing replication stress and activating the DNA damage response. Polyploid granuloma-resident macrophages formed via modified cell divisions and mitotic defects and not…

Screening of herbal extracts for TLR2- and TLR4-dependent anti-inflammatory effects.

2018

Herbal extracts represent an ample source of natural compounds, with potential to be used in improving human health. There is a growing interest in using natural extracts as possible new treatment strategies for inflammatory diseases. We therefore aimed at identifying herbal extracts that affect inflammatory signaling pathways through toll-like receptors (TLRs), TLR2 and TLR4. Ninety-nine ethanolic extracts were screened in THP-1 monocytes and HeLa-TLR4 transfected reporter cells for their effects on stimulated TLR2 and TLR4 signaling pathways. The 28 identified anti-inflammatory extracts were tested in comparative assays of stimulated HEK-TLR2 and HEK-TLR4 transfected reporter cells to dif…

Role of Toll-like receptors in systemic Candida albicans infections.

2009

Toll-like receptors (TLRs) constitute a family of pattern-recognition receptors (PRRs) that recognize molecular signatures of microbial pathogens and function as sensors for infection that induce the activation of the innate immune responses as well as the subsequent development of adaptive immune responses. It is well established that TLRs, mainly TLR2 and TLR4, are involved in the host interaction with Candida albicans and play a significant role in the development of host immune responses during candidiasis. Recognition of C. albicans by TLRs on the phagocytic cells activates intracellular signaling pathways that trigger production of proinflammatory cytokines that are critical for innat…

Ceftaroline modulates the innate immune and host defense responses of immunocompetent cells exposed to cigarette smoke.

2017

Abstract Background Cigarette smoke, the principal risk factor for chronic obstructive pulmonary disease (COPD), negatively influences the effectiveness of the immune system’s response to a pathogen. The antibiotic ceftaroline exerts immune-modulatory effects in bronchial epithelial cells exposed to cigarette smoke. Aims and methods The present study aims to assess the effects of ceftaroline on TLR2 and TLR4 expression, LPS binding and TNF-α and human beta defensin (HBD2) release in an undifferentiated and PMA-differentiated human monocyte cell line (THP-1) exposed or not to cigarette smoke extracts (CSE). TLR2, TLR4, and LPS binding were assessed by flow cytometry, TNF-α and HBD2 release w…

The Commensal Microbiota Enhances ADP-Triggered Integrin αIIbβ3 Activation and von Willebrand Factor-Mediated Platelet Deposition to Type I Collagen

2020

The commensal microbiota is a recognized enhancer of arterial thrombus growth. While several studies have demonstrated the prothrombotic role of the gut microbiota, the molecular mechanisms promoting arterial thrombus growth are still under debate. Here, we demonstrate that germ-free (GF) mice, which from birth lack colonization with a gut microbiota, show diminished static deposition of washed platelets to type I collagen compared with their conventionally raised (CONV-R) counterparts. Flow cytometry experiments revealed that platelets from GF mice show diminished activation of the integrin αIIbβ3 (glycoprotein IIbIIIa) when activated by the platelet agonist adenosine diphosphate (ADP). Fu…

Systemic Candidiasis and TLR2 Agonist Exposure Impact the Antifungal Response of Hematopoietic Stem and Progenitor Cells.

2018

We have previously demonstrated that Candida albicans induces differentiation of hematopoietic stem and progenitor cells (HSPCs) toward the myeloid lineage both in vitro and in vivo in a TLR2- and Dectin-1-dependent manner, giving rise to functional macrophages. In this work, we used an ex vivo model to investigate the functional consequences for macrophages derived from HSPCs in vivo-exposed to Pam3CSK4 (a TLR2 agonist) or C. albicans infection. Short in vivo treatment of mice with Pam3CSK4 results in a tolerized phenotype of ex vivo HSPC-derived macrophages, whereas an extended Pam3CSK4 treatment confers a trained phenotype. Early during candidiasis, HSPCs give rise to macrophages trained…

Association of Toll-like receptors 2, 3, and 4 genes polymorphisms with periapical pathosis risk

2016

Background: The aim of this study was to investigate the role of gene variations of Toll-like receptors (TLR) 2, 3, and 4 on genetic susceptibility to periapical pathosis. Material and Methods: One hundred patients were included in the study and divided into two groups as follows; Control Group (n=50) that have root canal treatment and no periapical lesion, Patient Group (n=50) that have root canal treatment and periapical lesion. TLR2 Arg753Gln, TLR3 (c.1377C/T) and TLR4 Asp299Gly and Thr399Ile polymorphisms were genotyped by using PCR-RFLP. Genotypical analysis of control and patient groups were investigated to disclose whether there is any association between periapical lesions and gene …

2017

Danger associated molecular patterns (DAMPs) are released by damaged cells and trigger neuroinflammation through activation of non-specific pattern recognition receptors (PRRs), e.g. Toll-like receptors (TLRs). Since the role of TLR 2 and 4 after traumatic brain injury (TBI) is still unclear, we examined the outcome and the expression of proinflammatory mediators after experimental TBI in Tlr2/4 / and wild-type (WT) mice. Tlr2/4 / and wild-type mice were subjected to controlled cortical injury and contusion volume and brain edema formation were assessed 24 h thereafter. Expression of inflammatory markers in brain tissue was measured by quantitative PCR 15 min, 3, 6, 12, and 24 h after contr…