scholarly journals Protective effect of Lactobacillus reuteri DSM 17938 against experimental necrotizing enterocolitis is mediated by Toll-like receptor 2

2018 ◽  
Vol 315 (2) ◽  
pp. G231-G240 ◽  
Author(s):  
Thomas K. Hoang ◽  
Baokun He ◽  
Ting Wang ◽  
Dat Q. Tran ◽  
J. Marc Rhoads ◽  
...  
Keyword(s):  
T Cells ◽  
Necrotizing Enterocolitis ◽  
Immune Modulation ◽  
Lactobacillus Reuteri ◽  
Inflammatory Responses ◽  
Cow Milk ◽  
Toll Like Receptor ◽  
Toll Like Receptor 2 ◽  
Anti Inflammatory

Lactobacillus reuteri DSM 17938 (LR 17938) has been shown to reduce the incidence and severity of necrotizing enterocolitis (NEC). It is unclear if preventing NEC by LR 17938 is mediated by Toll-like receptor 2 (TLR2), which is known to mediate proinflammatory responses to bacterial cell wall components. NEC was induced in newborn TLR2−/− or wild-type (WT) mice by the combination of gavage-feeding cow milk-based formula and exposure to hypoxia and cold stress. Treatment groups were administered formula supplemented with LR 17938 or placebo (deMan-Rogosa-Sharpe media). We observed that LR 17938 significantly reduced the incidence of NEC and reduced the percentage of activated effector CD4+T cells, while increasing Foxp3+ regulatory T cells in the intestinal mucosa of WT mice with NEC, but not in TLR2−/− mice. Dendritic cell (DC) activation by LR 17938 was mediated by TLR2. The percentage of tolerogenic DC in the intestine of WT mice was increased by LR 17938 treatment during NEC, a finding not observed in TLR2−/− mice. Furthermore, gut levels of proinflammatory cytokines IL-1β and IFN-γ were decreased after treatment with LR 17938 in WT mice but not in TLR2−/− mice. In conclusion, the combined in vivo and in vitro findings suggest that TLR2 receptors are involved in DC recognition and DC-priming of T cells to protect against NEC after oral administration of LR 17938. Our studies further clarify a major mechanism of probiotic LR 17938 action in preventing NEC by showing that neonatal immune modulation of LR 17938 is mediated by a mechanism requiring TLR2. NEW & NOTEWORTHY Lactobacillus reuteri DSM 17938 (LR 17938) has been shown to protect against necrotizing enterocolitis (NEC) in neonates and in neonatal animal models. The role of Toll-like receptor 2 (TLR2) as a sensor for gram-positive probiotics, activating downstream anti-inflammatory responses is unclear. Our current studies examined TLR2 −/− mice subjected to experimental NEC and demonstrated that the anti-inflammatory effects of LR 17938 are mediated via a mechanism requiring TLR2.

scholarly journals Distinct Roles for MyD88 and Toll-Like Receptor 2 during Leishmania braziliensis Infection in Mice

2009 ◽  
Vol 77 (7) ◽  
pp. 2948-2956 ◽  
Author(s):  
Diego A. Vargas-Inchaustegui ◽  
Wendy Tai ◽  
Lijun Xin ◽  
Alison E. Hogg ◽  
David B. Corry ◽  
...  
Keyword(s):  
T Cells ◽  
Protective Immunity ◽  
Interleukin 12 ◽  
Leishmania Braziliensis ◽  
Toll Like Receptor ◽  
Enhanced Resistance ◽  
Toll Like Receptor 2 ◽  
Resistance To Infection

ABSTRACT We have previously reported that Leishmania braziliensis infection can activate murine dendritic cells (DCs) and upregulate signaling pathways that are essential for the initiation of innate immunity. However, it remains unclear whether Toll-like receptors (TLRs) are involved in L. braziliensis-mediated DC activation. To address this issue, we generated bone marrow-derived DCs from MyD88−/− and TLR2−/− mice and examined their responsiveness to parasite infection. While wild-type DCs were efficiently activated to produce cytokines and prime naïve CD4+ T cells, L. braziliensis-infected MyD88−/− DCs exhibited less activation and decreased production of interleukin-12 (IL-12) p40. Furthermore, MyD88−/− mice were more susceptible to infection in that they developed larger and prolonged lesions compared to those in control mice. In sharp contrast, the lack of TLR2 resulted in an enhanced DC activation and increased IL-12 p40 production after infection. As such, L. braziliensis-infected TLR2−/− DCs were more competent in priming naïve CD4+ T cells in vitro than were their controls, findings which correlated with an increased gamma interferon production in vivo and enhanced resistance to infection. Our results suggest that while MyD88 is indispensable for the generation of protective immunity to L. braziliensis, TLR2 seems to have a regulatory role during infection.

scholarly journals Toll-Like Receptor 2-Dependent Extracellular Signal-Regulated Kinase Signaling in Mycobacterium tuberculosis-Infected Macrophages Drives Anti-Inflammatory Responses and Inhibits Th1 Polarization of Responding T Cells

2015 ◽  
Vol 83 (6) ◽  
pp. 2242-2254 ◽  
Author(s):  
Edward T. Richardson ◽  
Supriya Shukla ◽  
David R. Sweet ◽  
Pamela A. Wearsch ◽  
Philip N. Tsichlis ◽  
...  
Keyword(s):  
T Cells ◽  
Mycobacterium Tuberculosis ◽  
Erk Signaling ◽  
Toll Like Receptor ◽  
Content Type ◽  
Extracellular Signal ◽  
Toll Like Receptor 2 ◽  
Ifn Γ ◽  
Anti Inflammatory ◽  
Th1 Polarization

Mycobacterium tuberculosissurvives within macrophages and employs immune evasion mechanisms to persist in the host. Protective T helper type 1 (Th1) responses are induced, and the immune response in most individuals is sufficient to restrictM. tuberculosisto latent infection, but most infections are not completely resolved. As T cells and macrophages respond, a balance is established between protective Th1-associated and other proinflammatory cytokines, such as interleukin-12 (IL-12), interferon gamma (IFN-γ), and tumor necrosis factor alpha, and anti-inflammatory cytokines, such as IL-10. The mechanisms by whichM. tuberculosismodulates host responses to promote its survival remain unclear. In these studies, we demonstrate thatM. tuberculosisinduction of IL-10, suppression of IL-12, and inhibition of class II major histocompatibility complex (MHC-II) molecules in infected macrophages are all driven by Toll-like receptor 2 (TLR2)-dependent activation of the extracellular signal-regulated kinases (ERK). Elimination of ERK signaling downstream of TLR2 by pharmacologic inhibition with U0126 or genetic deletion ofTpl2blocks IL-10 secretion and enhances IL-12 p70 secretion. We demonstrate thatM. tuberculosisregulation of these pathways in macrophages affects T cell responses to infected macrophages. Thus, genetic blockade of the ERK pathway inTpl2−/−macrophages enhances Th1 polarization and IFN-γ production by antigen-specific CD4+T cells responding toM. tuberculosisinfection. These data indicate thatM. tuberculosisand its potent TLR2 ligands activate ERK signaling in macrophages to promote anti-inflammatory macrophage responses and blunt Th1 responses against the pathogen.

scholarly journals Development of a Secondary Immune Response toMycobacterium tuberculosisIs Independent of Toll-Like Receptor 2

2010 ◽  
Vol 79 (3) ◽  
pp. 1118-1123 ◽  
Author(s):  
Amanda McBride ◽  
Kamlesh Bhatt ◽  
Padmini Salgame
Keyword(s):  
Immune Response ◽  
T Cells ◽  
Host Resistance ◽  
Toll Like Receptor ◽  
Response Phenotype ◽  
Toll Like Receptor 2 ◽  
Antigen Presenting ◽  
Memory Immune Response

ABSTRACTPublished work indicates that the contribution of Toll-like receptor 2 (TLR2) to host resistance during acuteMycobacterium tuberculosisinfection is marginal. However, in these studies, TLR2 participation in the memory immune response toM. tuberculosiswas not determined. The substantialin vitroevidence thatM. tuberculosisstrongly triggers TLR2 on dendritic cells and macrophages to bring about either activation or inhibition of antigen-presenting cell (APC) functions, along with accumulating evidence that memory T cell development can be calibrated by TLR signals, led us to question the role of TLR2 in host resistance to secondary challenge withM. tuberculosis. To address this question, a memory immunity model was employed, and the response of TLR2-deficient (TLR2 knockout [TLR2KO]) mice following a secondary exposure toM. tuberculosiswas compared to that of wild-type (WT) mice based on assessment of the bacterial burden, recall response, phenotype of recruited T cells, and granulomatous response. We found that upon rechallenge withM. tuberculosis, both WT and TLR2KO immune mice displayed similarly enhanced resistance to infection in comparison to their naïve counterparts. The frequencies ofM. tuberculosis-specific gamma interferon (IFN-γ)-producing T cells, the phenotypes of recruited T cells, and the granulomatous responses were also similar between WT and TLR2KO immune mice. Together, the findings from this study indicate that TLR2 signaling does not influence memory immunity toM. tuberculosis.

scholarly journals Serine Lipids of Porphyromonas gingivalis Are Human and Mouse Toll-Like Receptor 2 Ligands

2013 ◽  
Vol 81 (9) ◽  
pp. 3479-3489 ◽  
Author(s):  
Robert B. Clark ◽  
Jorge L. Cervantes ◽  
Mark W. Maciejewski ◽  
Vahid Farrokhi ◽  
Reza Nemati ◽  
...  
Keyword(s):  
Cell Activation ◽  
Inflammatory Responses ◽  
Periodontal Pathogen ◽  
Toll Like Receptor ◽  
Dendritic Cell Activation ◽  
Content Type ◽  
Hek Cells ◽  
Toll Like Receptor 2

ABSTRACTThe total cellular lipids ofPorphyromas gingivalis, a known periodontal pathogen, were previously shown to promote dendritic cell activation and inhibition of osteoblasts through engagement of Toll-like receptor 2 (TLR2). The purpose of the present investigation was to fractionate all lipids ofP. gingivalisand define which lipid classes account for the TLR2 engagement, based on bothin vitrohuman cell assays andin vivostudies in mice. Specific serine-containing lipids ofP. gingivalis, called lipid 654 and lipid 430, were identified in specific high-performance liquid chromatography fractions as the TLR2-activating lipids. The structures of these lipids were defined using tandem mass spectrometry and nuclear magnetic resonance methods.In vitro, both lipid 654 and lipid 430 activated TLR2-expressing HEK cells, and this activation was inhibited by anti-TLR2 antibody. In contrast, TLR4-expressing HEK cells failed to be activated by either lipid 654 or lipid 430. Wild-type (WT) or TLR2-deficient (TLR2−/−) mice were injected with either lipid 654 or lipid 430, and the effects on serum levels of the chemokine CCL2 were measured 4 h later. Administration of either lipid 654 or lipid 430 to WT mice resulted in a significant increase in serum CCL2 levels; in contrast, the administration of lipid 654 or lipid 430 to TLR2−/−mice resulted in no increase in serum CCL2. These results thus identify a new class of TLR2 ligands that are produced byP. gingivalisthat likely play a significant role in mediating inflammatory responses both at periodontal sites and, potentially, in other tissues where these lipids might accumulate.

scholarly journals Microbial Amyloids Induce Interleukin 17A (IL-17A) and IL-22 Responses via Toll-Like Receptor 2 Activation in the Intestinal Mucosa

2012 ◽  
Vol 80 (12) ◽  
pp. 4398-4408 ◽  
Author(s):  
Jessalyn H. Nishimori ◽  
Tiffanny N. Newman ◽  
Gertrude O. Oppong ◽  
Glenn J. Rapsinski ◽  
Jui-Hung Yen ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Intestinal Mucosa ◽  
Amyloid Fibrils ◽  
Inflammatory Responses ◽  
Toll Like Receptor ◽  
T Helper ◽  
Content Type ◽  
Interleukin 17A ◽  
Toll Like Receptor 2

ABSTRACTThe Toll-like receptor 2 (TLR2)/TLR1 receptor complex responds to amyloid fibrils, a common component of biofilm material produced by members of the phylaFirmicutes,Bacteroidetes, andProteobacteria. To determine whether this TLR2/TLR1 ligand stimulates inflammatory responses when bacteria enter intestinal tissue, we investigated whether expression of curli amyloid fibrils by the invasive enteric pathogenSalmonella entericaserotype Typhimurium contributes to T helper 1 and T helper 17 responses by measuring cytokine production in the mouse colitis model. AcsgBAmutant, deficient in curli production, elicited decreased expression of interleukin 17A (IL-17A) and IL-22 in the cecal mucosa compared to theS. Typhimurium wild type. In TLR2-deficient mice, IL-17A and IL-22 expression was blunted duringS. Typhimurium infection, suggesting that activation of the TLR2 signaling pathway contributes to the expression of these cytokines. T cells incubated with supernatants from bone marrow-derived dendritic cells (BMDCs) treated with curli fibrils released IL-17A in a TLR2-dependent mannerin vitro. Lower levels of IL-6 and IL-23 production were detected in the supernatants of the TLR2-deficient BMDCs treated with curli fibrils. Consistent with this, three distinct T-cell populations—CD4+T helper cells, cytotoxic CD8+T cells, and γδ T cells—produced IL-17A in response to curli fibrils in the intestinal mucosa duringS. Typhimurium infection. Notably, decreased IL-6 expression by the dendritic cells and decreased IL-23 expression by the dendritic cells and macrophages were observed in the cecal mucosa of mice infected with the curli mutant. We conclude that TLR2 recognition of bacterial amyloid fibrils in the intestinal mucosa represents a novel mechanism of immunoregulation, which contributes to the generation of inflammatory responses, including production of IL-17A and IL-22, in response to bacterial entry into the intestinal mucosa.

scholarly journals Aspergillus fumigatus Influences Gasdermin-D-Dependent Pyroptosis of the Lung via Regulating Toll-Like Receptor 2-Mediated Regulatory T Cell Differentiation

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Wei Yan ◽  
Yi-si Zhao ◽  
Ke Xie ◽  
Yu Xing ◽  
Fang Xu
Keyword(s):  
Flow Cytometry ◽  
T Cells ◽  
Cell Differentiation ◽  
Lung Tissue ◽  
Regulatory T Cell ◽  
T Cell Differentiation ◽  
Lung Damage ◽  
Toll Like Receptor ◽  
Toll Like Receptor 2

Purpose. Aspergillus fumigatus, as an opportunistic fungus, has developed a series of escape mechanisms under the host’s immune response to obtain nutrients and promote fungal growth in the hostile environment. The immune escape of pathogens may be through suppressing the inflammatory response mediated by regulatory T cells (Tregs). The aim of this study was to explore whether A. fumigatus influences Gasdermin-D-dependent pyroptosis of the lung by regulating Toll-like receptor 2-mediated regulatory T cell differentiation. Methods. Collect peripheral blood from patients with A. fumigatus. ELISA kits we used to detect the expression levels of IL-1β, IL-6, IL-2R, and IL-10 in the serum and flow cytometry to detect the percentage of CD4+CD25+Foxp3+ Tregs in the patients’ peripheral blood mononuclear cells (PBMCs). The mouse model of A. fumigatus infection was constructed by tracheal instillation. The pathological changes in the lungs of the mice were observed under a microscope. The fungal load in the lung tissue was determined by the plate colony count. ELISA kit was used to detect the lung tissue homogenate proinflammatory cytokines TNF-α, IL-6, CCL2, and VEGF. Q-PCR was used for the detection of the expression of Foxp3 and TLR2 genes in the lung. Western blot was used for the detection of the expression of TLR2, Gasdermin-D (GSDMD), IL-1α, and IL-1β in the lung. Flow cytometry was used to detect splenic CD4+CD25+FOXP3+ Tregs. Using magnetic beads to extract CD4+ T cells from mice spleen, the effects of A. fumigatus conidia or TLR2 inhibitor (C29) to differentiate CD4+ T cells in vitro were tested. Results. The expression of Foxp3 and TLR2 in the lung tissue of mice infected with A. fumigatus increased, and we observed that the proportion of Tregs in both A. fumigatus infection patients and mice was upregulated. After using the CD25 neutralizing antibody, the number of Tregs in the mice spleen was significantly reduced. However, lung damage was reduced and the ability to clear lung fungi was enhanced. We found that the Tregs in TLR 2 − / − mice were significantly reduced and the nonlethal dose of A. fumigatus conidia did not cause severe lung damage in TLR 2 − / − mice. Compared with that of wild-type mice, the fungal burden in the lung of TLR2-deficient mice was reduced and the knockout of TLR2 changed the expression of GSDMD, IL-1α, and IL-1β in A. fumigatus. In in vitro experiments, we found that the inhibition of TLR2 can reduce Treg differentiation. Conclusions. A. fumigatus triggers CD4+CD25+FOXP3+ Treg proliferation and differentiation by activating the TLR2 pathway, which may be a potential mechanism for evading host defenses in A. fumigatus. This effect can modulate GSDMD-dependent pyroptosis and may partly involve TRL2 signaling.

1054 - Toll-Like Receptor 2 Plays a Key Role in Protection Against Severe Necrotizing Enterocolitis by Lactobacillus Reuteri Dsm 17938

2018 ◽  
Vol 154 (6) ◽  
pp. S-199-S-200
Author(s):  
Thomas K. Hoang ◽  
Yuying Liu ◽  
Baokun He ◽  
Ting Wang ◽  
Dat Q. Tran ◽  
...  
Keyword(s):  
Necrotizing Enterocolitis ◽  
Lactobacillus Reuteri ◽  
Toll Like Receptor ◽  
Toll Like Receptor 2

scholarly journals Dietary Chitin Particles Called Mimetic Fungi Ameliorate Colitis in Toll-Like Receptor 2/CD14- and Sex-Dependent Manners

2019 ◽  
Vol 87 (5) ◽  
Author(s):  
Patricia Louis ◽  
Brian Mercer ◽  
Aiko M. Cirone ◽  
Christina Johnston ◽  
Zachary J. Lee ◽  
...  
Keyword(s):  
Toll Like Receptor ◽  
Fungal Cell ◽  
Size Dependent ◽  
Major Structural Component ◽  
Acidic Mammalian Chitinase ◽  
Inflammatory Bowel ◽  
Toll Like Receptor 2 ◽  
Anti Inflammatory ◽  
Inflammatory Effect

ABSTRACTChitin is a naturalN-acetylglucosamine polymer and a major structural component of fungal cell walls. Dietary chitin is mucoadhesive; anti-inflammatory effects of chitin microparticles (CMPs; 1- to 10-μm diameters) have been demonstrated in models of inflammatory bowel disease (IBD). The goals of this study were to assess (i) whether CMPs among various chitin preparations are the most effective against colitis in male and female mice and (ii) whether host chitin-binding Toll-like receptor 2 (TLR2) and CD14 are required for the anti-inflammatory effect of chitin. We found that colitis in male mice was ameliorated by CMPs and large chitin beads (LCBs; 40 to 70 μm) but not by chitosan (deacetylated chitin) microparticles, oligosaccharide chitin, or glucosamine. In fact, LCBs were more effective than CMPs. In female colitis, on the other hand, CMPs and LCBs were equally and highly effective. Neither sex of TLR2-deficient mice showed anti-inflammatory effects when treated with LCBs. No anti-inflammatory effect of LCBs was seen in either CD14-deficient males or females. Furthermore, anin vitrostudy indicated that when LCBs and CMPs were digested with stomach acidic mammalian chitinase (AMC), their size-dependent macrophage activations were modified, at least in part, suggesting reduced particle sizes of dietary chitin in the stomach. Interestingly, stomach AMC activity was greater in males than females. Our results indicated that dietary LCBs were the most effective preparation for treating colitis in both sexes; these anti-inflammatory effects of LCBs were dependent on host TLR2 and CD14.

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