Search results for "Polysaccharides"
showing 10 items of 413 documents
Skin-derived macrophages from Leishmania major-susceptible mice exhibit interleukin-12- and interferon-gamma-independent nitric oxide production and …
2002
Co-administration of CpG-containing immunostimulatory oligodeoxynucleotides and parasite antigen protects susceptible BALB/c mice from otherwise progressive infection with Leishmania major. Although the protective effect of CpG-containing immunostimulatory oligodeoxynucleotides is clearly dependent on endogenous interleukin-12 and interferon-gamma production, the source of these Th1-promoting cytokines in infected mice is unknown. In contrast to macrophages from Leishmania-resistant C57BL/6 mice, macrophages from susceptible BALB/c mice are hyporesponsive to stimulation with lipopolysaccharide and interferon-gamma. While studying interactions of various antigen-presenting cells with Leishma…
Phosphate Groups in the Lipid A Moiety Determine the Effects of LPS on Hepatic Stellate Cells: A Role for LPS-Dephosphorylating Activity in Liver Fib…
2020
Alkaline phosphatase (AP) activity is highly upregulated in plasma during liver diseases. Previously, we demonstrated that AP is able to detoxify lipopolysaccharide (LPS) by dephosphorylating its lipid A moiety. Because a role of gut-derived LPS in liver fibrogenesis has become evident, we now examined the relevance of phosphate groups in the lipid A moiety in this process. The effects of mono-phosphoryl and di-phosphoryl lipid A (MPLA and DPLA, respectively) were studied in vitro and LPS-dephosphorylating activity was studied in normal and fibrotic mouse and human livers. The effects of intestinal AP were studied in mice with CCL4-induced liver fibrosis. DPLA strongly stimulated fibrogenic…
Transcriptional regulation of miR-224 upregulated in human HCCs by NFκB inflammatory pathways
2012
Background & Aims: miR-224 is up-regulated in human HCCs as compared to both paired peri-tumoral cirrhotic tissues and cirrhotic livers without HCC. Here, we have cloned the miR-224 regulatory region and characterized its transcriptional regulation by the NFκB-dependent inflammatory pathways. Methods: Mature miRNA expression was evaluated by a 2 step stem-loop real-time RT-PCR. The recruitment of polymerase II and transcription factors on the pre-miR-224 promoter has been assessed by ChIPSeq and ChIP. Results: We found miR-224 levels strongly up-regulated in both peri-tumoral cirrhotic livers and HCC samples as compared to normal livers. In silico analysis of the putative miR-224 promoter r…
Circulating levels of 3-hydroxymyristate, a direct quantification of endotoxaemia in noninfected cirrhotic patients
2019
IF 4.5; International audience; Background & AimsThe quantification of lipopolysaccharide (LPS) in biological fluids is challenging. We aimed to measure plasma LPS concentration using a new method of direct quantification of 3‐hydroxymyristate (3‐HM), a lipid component of LPS, and to evaluate correlations between 3‐HM and markers of liver function, endothelial activation, portal hypertension and enterocyte damage.MethodsPlasma from 90 noninfected cirrhotic patients (30 Child‐Pugh [CP]‐A, 30 CP‐B, 30 CP‐C) was prospectively collected. The concentration of 3‐HM was determined by high‐performance liquid chromatography coupled with mass spectrometry.Results3‐HM levels were higher in CP‐C patien…
Compartmentalized production of CCL17 in vivo: strong inducibility in peripheral dendritic cells contrasts selective absence from the spleen.
2003
Dendritic cells (DCs)(*) fulfill an important regulatory function at the interface of the innate and adaptive immune system. The thymus and activation-regulated chemokine (TARC/CCL17) is produced by DCs and facilitates the attraction of activated T cells. Using a fluorescence-based in vivo reporter system, we show that CCL17 expression in mice is found in activated Langerhans cells and mature DCs located in various lymphoid and nonlymphoid organs, and is up-regulated after stimulation with Toll-like receptor ligands. DCs expressing CCL17 belong to the CD11b(+)CD8(-)Dec205(+) DC subset, including the myeloid-related DCs located in the subepithelial dome of Peyer's patches. CCL17-deficient mi…
Immune Cell Toll-like Receptor 4 Mediates the Development of Obesity- and Endotoxemia-Associated Adipose Tissue Fibrosis
2014
International audience; Adipose tissue fibrosis development blocks adipocyte hypertrophy and favors ectopic lipid accumulation. Here, we show that adipose tissue fibrosis is associated with obesity and insulin resistance in humans and mice. Kinetic studies in C3H mice fed a high-fat diet show activation of macrophages and progression of fibrosis along with adipocyte metabolic dysfunction and death. Adipose tissue fibrosis is attenuated by macrophage depletion. Impairment of Toll-like receptor 4 signaling protects mice from obesity-induced fibrosis. The presence of a functional Toll-like receptor 4 on adipose tissue hematopoietic cells is necessary for the initiation of adipose tissue fibros…
6-Dimethylamino 1H-pyrazolo[3,4-d]pyrimidine derivatives as new inhibitors of inflammatory mediators in intact cells.
2003
The synthesis of 6-dimethylamino 1H-pyrazolo[3,4-d]pyrimidines substituted at positions 1 and 4, and their effects on murine macrophage and human neutrophil functions are described. Several compounds and especially 4b-6b are potent inhibitors of PGE2 generation in murine macrophages. This action is related to a direct effect on COX-2 activity without affecting the enzyme expression. Some of these compounds also inhibited COX-1 and COX-2 in human monocytes and 4b showed selectivity for COX-2 inhibition. © 2003 Elsevier Science Ltd. All rights reserved.
Inflammation et maladies métaboliques : analyse par imagerie du métabolisme des lipoprotéines et lipopolysaccharides au cours de l’inflammation
2021
LPS (lipopolysaccharides) are endotoxins originating from Gram-negative bacteria. They have been extensively described for their ability to interact with and disrupt the intestinal barrier. These toxins are able to cross the gut barrier and to pass into the blood (endotoxemia), leading tolow-grade metabolic inflammation or to a severe inflammatory syndrome (SIRS). Fortunately, some circulating proteins such as PLTP (Phospholipid Transfer Protein) are able to transfer LPS to plasma lipoproteins in order to inactivate and detoxify them.The main goals of this study were to investigate the metabolic fate of LPS from the gut and peritoneal cavity but also the influence of PLTP on these toxins in…
Assessing the Cost of Mounting an Immune Response
2003
International audience; The evolution of parasite resistance has often been assumed to be governed by antagonistic selection pressures. Defense against pathogens, by mounting an immune response, confers evident benefits but may also incur costs, so that the optimal level of defense is expected to depend on the balance between benefits and costs. Although the benefits of immune surveillance are well known, estimates of costs are still equivocal. Here we studied the behavioral and physiological modifications associated with exposure to a onreplicating antigen (lipopolysaccharide [LPS] of Escherichia coli) in a passerine species, the house sparrow (Passer domesticus).We further investigated wh…
Parental experience of a risky environment leads to improved offspring growth rate.
2014
Abstract Parasites (or diseases) are major selective force for the evolution of life history traits and parasite-host evolution. Mothers can show a variety of responses to parasites during pregnancy with different consequences for them or their offspring. However, whether information in the maternal environment before pregnancy can cause a change in the phenotype of the offspring is unknown. To avoid the confounding effect of pathogens and to reduce the risk of direct effect of mother's immune activation, we injected female laboratory mice with lipopolysaccharides (LPS) before mating. In order to provide a constant information on the potential infectious risk of the environment, females wer…