Blockade of TLR2 and TLR4 Attenuates Inflammatory Response and Parasite Load in Cutaneous Leishmaniasis

Human cutaneous leishmaniasis (CL) caused by Leishmania braziliensis is characterized by a pronounced inflammatory response associated with ulcer development. Monocytes/macrophages, the main cells harboring parasites, are largely responsible for parasite control. Toll-like receptor (TLR) signaling leads to the transcription of inflammatory mediators, such as IL-1β and TNF during innate immune response. TLR antagonists have been used in the treatment of inflammatory disease. The neutralization of these receptors may attenuate an exacerbated inflammatory response. We evaluated the ability of TLR2 and TLR4 antagonists to modulate host immune response in L. braziliensis-infected monocytes and cells from CL patient skin lesions. Following TLR2 and TLR4 neutralization, decreased numbers of infected cells and internalized parasites were detected in CL patient monocytes. In addition, reductions in oxidative burst, IL-1β, TNF and CXCL9 production were observed. TNF production by cells from CL lesions also decreased after TLR2 and TLR4 neutralization. The attenuation of host inflammatory response after neutralizing these receptors suggests the potential of TLR antagonists as immunomodulators in association with antimonial therapy in human cutaneous leishmaniasis.

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Keratinocytes and Activation of TREM-1 Pathway in Cutaneous Leishmaniasis Lesions

Microbiology Research ◽

10.3390/microbiolres12040056 ◽

2021 ◽

Vol 12 (4) ◽

pp. 765-778

Author(s):

Sara Nunes ◽

Mariana Rosa Ampuero ◽

Ícaro Bonyek-Silva ◽

Reinan Lima ◽

Filipe Rocha Lima ◽

...

Keyword(s):

Immune Response ◽

Cutaneous Leishmaniasis ◽

Tissue Damage ◽

Inflammatory Diseases ◽

Critical Role ◽

Human Keratinocytes ◽

Skin Lesions ◽

Leishmania Braziliensis ◽

Adapter Protein ◽

Skin Cells

Triggering Receptor Expressed on Myeloid Cells 1 (TREM-1) amplifies the immune response, operating synergistically with Toll-Like Receptors (TLRs) in the production of inflammatory mediators. TREM-1 signaling depends on the adapter protein DAP12, which results in the activation of NFkB, the expression of inflammatory genes, and the release of antimicrobial peptides, such as Beta-defensin 2. We evaluated the activation of the TREM-1 signaling pathways in Cutaneous Leishmaniasis (CL) caused by Leishmania braziliensis and linage human keratinocytes exposed to these parasites since the host immune response against Leishmania plays a critical role in promoting parasite killing but also participates in inflammation and tissue damage. We analyzed publicly available transcriptome data from the lesions of CL patients. In the CL biopsies, we found increased expression of the molecules involved in the TREM-1 pathway. We then validated these findings with RT-qPCR and immunohistochemistry in newly obtained biopsies. Surprisingly, we found a strong labeling of TREM-1 in keratinocytes, prompting the hypothesis that increased TREM-1 activation may be the result of tissue damage. However, increased TREM-1 expression was only seen in human lineage keratinocytes following parasite stimulation. Moreover, no up-regulation of TREM-1 expression was observed in the skin lesions caused by other non-infectious inflammatory diseases. Together, these findings indicate that L. braziliensis (Lb) induces the expression of the TREM-1 receptor in tissue keratinocytes regardless of tissue damage, suggesting that non-immune skin cells may play a role in the inflammatory response of CL.

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TIFA Signaling in Gastric Epithelial Cells Initiates the cag Type 4 Secretion System-Dependent Innate Immune Response to Helicobacter pylori Infection

mBio ◽

10.1128/mbio.01168-17 ◽

2017 ◽

Vol 8 (4) ◽

Cited By ~ 54

Author(s):

Alevtina Gall ◽

Ryan G. Gaudet ◽

Scott D. Gray-Owen ◽

Nina R. Salama

Keyword(s):

Immune Response ◽

Helicobacter Pylori ◽

Epithelial Cells ◽

Inflammatory Response ◽

Secretion System ◽

Innate Immune ◽

Gastric Ulcers ◽

Bacterial Clearance ◽

Gastric Epithelial Cells ◽

H Pylori

ABSTRACT Helicobacter pylori is a bacterial pathogen that colonizes the human stomach, causing inflammation which, in some cases, leads to gastric ulcers and cancer. The clinical outcome of infection depends on a complex interplay of bacterial, host genetic, and environmental factors. Although H. pylori is recognized by both the innate and adaptive immune systems, this rarely results in bacterial clearance. Gastric epithelial cells are the first line of defense against H. pylori and alert the immune system to bacterial presence. Cytosolic delivery of proinflammatory bacterial factors through the cag type 4 secretion system ( cag -T4SS) has long been appreciated as the major mechanism by which gastric epithelial cells detect H. pylori . Classically attributed to the peptidoglycan sensor NOD1, recent work has highlighted the role of NOD1-independent pathways in detecting H. pylori ; however, the bacterial and host factors involved have remained unknown. Here, we show that bacterially derived heptose-1,7-bisphosphate (HBP), a metabolic precursor in lipopolysaccharide (LPS) biosynthesis, is delivered to the host cytosol through the cag -T4SS, where it activates the host tumor necrosis factor receptor-associated factor (TRAF)-interacting protein with forkhead-associated domain (TIFA)-dependent cytosolic surveillance pathway. This response, which is independent of NOD1, drives robust NF-κB-dependent inflammation within hours of infection and precedes NOD1 activation. We also found that the CagA toxin contributes to the NF-κB-driven response subsequent to TIFA and NOD1 activation. Taken together, our results indicate that the sequential activation of TIFA, NOD1, and CagA delivery drives the initial inflammatory response in gastric epithelial cells, orchestrating the subsequent recruitment of immune cells and leading to chronic gastritis. IMPORTANCE H. pylori is a globally prevalent cause of gastric and duodenal ulcers and cancer. H. pylori antibiotic resistance is rapidly increasing, and a vaccine remains elusive. The earliest immune response to H. pylori is initiated by gastric epithelial cells and sets the stage for the subsequent immunopathogenesis. This study revealed that host TIFA and H. pylori -derived HBP are critical effectors of innate immune signaling that account for much of the inflammatory response to H. pylori in gastric epithelial cells. HBP is delivered to the host cell via the cag -T4SS at a time point that precedes activation of the previously described NOD1 and CagA inflammatory pathways. Manipulation of the TIFA-driven immune response in the host and/or targeting of ADP-heptose biosynthesis enzymes in H. pylori may therefore provide novel strategies that may be therapeutically harnessed to achieve bacterial clearance.

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Tumour viruses and innate immunity

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2016.0267 ◽

2017 ◽

Vol 372 (1732) ◽

pp. 20160267 ◽

Cited By ~ 13

Author(s):

Sharon E. Hopcraft ◽

Blossom Damania

Keyword(s):

Immune Response ◽

Inflammatory Response ◽

Viral Infection ◽

Innate Immune Response ◽

Innate Immune ◽

Host Cells ◽

Oncogenic Viruses ◽

Barr Virus ◽

Human T Cell ◽

Epstein Barr

Host cells sense viral infection through pattern recognition receptors (PRRs), which detect pathogen-associated molecular patterns (PAMPs) and stimulate an innate immune response. PRRs are localized to several different cellular compartments and are stimulated by viral proteins and nucleic acids. PRR activation initiates signal transduction events that ultimately result in an inflammatory response. Human tumour viruses, which include Kaposi's sarcoma-associated herpesvirus, Epstein–Barr virus, human papillomavirus, hepatitis C virus, hepatitis B virus, human T-cell lymphotropic virus type 1 and Merkel cell polyomavirus, are detected by several different PRRs. These viruses engage in a variety of mechanisms to evade the innate immune response, including downregulating PRRs, inhibiting PRR signalling, and disrupting the activation of transcription factors critical for mediating the inflammatory response, among others. This review will describe tumour virus PAMPs and the PRRs responsible for detecting viral infection, PRR signalling pathways, and the mechanisms by which tumour viruses evade the host innate immune system. This article is part of the themed issue ‘Human oncogenic viruses’.

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2,2’4,4’-Tetrabromodiphenyl Ether (PBDE-47) Modulates the Intracellular miRNA Profile, sEV Biogenesis and Their miRNA Cargo Exacerbating the LPS-Induced Pro-Inflammatory Response in THP-1 Macrophages

Frontiers in Immunology ◽

10.3389/fimmu.2021.664534 ◽

2021 ◽

Vol 12 ◽

Author(s):

Valeria Longo ◽

Alessandra Longo ◽

Giorgia Adamo ◽

Antonino Fiannaca ◽

Sabrina Picciotto ◽

...

Keyword(s):

Immune Response ◽

Inflammatory Response ◽

Innate Immune Response ◽

De Novo ◽

In Silico Analysis ◽

Innate Immune ◽

Macrophage Cell ◽

Intracellular Expression ◽

Different Levels ◽

Silico Analysis

The 2,2’4,4’-tetrabromodiphenyl ether (PBDE-47) is one of the most prominent PBDE congeners detected in the environment and in animal and human tissues. Animal model experiments suggested the occurrence of PBDE-induced immunotoxicity leading to different outcomes and recently we demonstrated that this substance can impair macrophage and basophil activities. In this manuscript, we decided to further examine the effects induced by PBDE-47 treatment on innate immune response by looking at the intracellular expression profile of miRNAs as well as the biogenesis, cargo content and activity of human M(LPS) macrophage cell-derived small extracellular vesicles (sEVs). Microarray and in silico analysis demonstrated that PBDE-47 can induce some epigenetic effects in M(LPS) THP-1 cells modulating the expression of a set of intracellular miRNAs involved in biological pathways regulating the expression of estrogen-mediated signaling and immune responses with particular reference to M1/M2 differentiation. In addition to the cell-intrinsic modulation of intracellular miRNAs, we demonstrated that PBDE-47 could also interfere with the biogenesis of sEVs increasing their number and selecting a de novo population of sEVs. Moreover, PBDE-47 induced the overload of specific immune related miRNAs in PBDE-47 derived sEVs. Finally, culture experiments with naïve M(LPS) macrophages demonstrated that purified PBDE-47 derived sEVs can modulate macrophage immune response exacerbating the LPS-induced pro-inflammatory response inducing the overexpression of the IL-6 and the MMP9 genes. Data from this study demonstrated that PBDE-47 can perturb the innate immune response at different levels modulating the intracellular expression of miRNAs but also interfering with the biogenesis, cargo content and functional activity of M(LPS) macrophage cell-derived sEVs.

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Ursodeoxycholic Acid (UDCA) Mitigates the Host Inflammatory Response during Clostridioides difficile Infection by Altering Gut Bile Acids

Infection and Immunity ◽

10.1128/iai.00045-20 ◽

2020 ◽

Vol 88 (6) ◽

Author(s):

Jenessa A. Winston ◽

Alissa J. Rivera ◽

Jingwei Cai ◽

Rajani Thanissery ◽

Stephanie A. Montgomery ◽

...

Keyword(s):

Immune Response ◽

Bile Acid ◽

Inflammatory Response ◽

Innate Immune Response ◽

Innate Immune ◽

Colonization Resistance ◽

Content Type ◽

Clostridioides Difficile

ABSTRACT Clostridioides difficile infection (CDI) is associated with increasing morbidity and mortality posing an urgent threat to public health. Recurrence of CDI after successful treatment with antibiotics is high, thus necessitating discovery of novel therapeutics against this enteric pathogen. Administration of the secondary bile acid ursodeoxycholic acid (UDCA; ursodiol) inhibits the life cycles of various strains of C. difficile in vitro, suggesting that the FDA-approved formulation of UDCA, known as ursodiol, may be able to restore colonization resistance against C. difficile in vivo. However, the mechanism(s) by which ursodiol is able to restore colonization resistance against C. difficile remains unknown. Here, we confirmed that ursodiol inhibits C. difficile R20291 spore germination and outgrowth, growth, and toxin activity in a dose-dependent manner in vitro. In a murine model of CDI, exogenous administration of ursodiol resulted in significant alterations in the bile acid metabolome with little to no changes in gut microbial community structure. Ursodiol pretreatment resulted in attenuation of CDI pathogenesis early in the course of disease, which coincided with alterations in the cecal and colonic inflammatory transcriptome, bile acid-activated receptors nuclear farnesoid X receptor (FXR) and transmembrane G-protein-coupled membrane receptor 5 (TGR5), which are able to modulate the innate immune response through signaling pathways such as NF-κB. Although ursodiol pretreatment did not result in a consistent decrease in the C. difficile life cycle in vivo, it was able to attenuate an overly robust inflammatory response that is detrimental to the host during CDI. Ursodiol remains a viable nonantibiotic treatment and/or prevention strategy against CDI. Likewise, modulation of the host innate immune response via bile acid-activated receptors FXR and TGR5 represents a new potential treatment strategy for patients with CDI.

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Mutations in a Highly Conserved Motif of nsp1β Protein Attenuate the Innate Immune Suppression Function of Porcine Reproductive and Respiratory Syndrome Virus

Journal of Virology ◽

10.1128/jvi.03069-15 ◽

2016 ◽

Vol 90 (7) ◽

pp. 3584-3599 ◽

Cited By ~ 23

Author(s):

Yanhua Li ◽

Duan-Liang Shyu ◽

Pengcheng Shang ◽

Jianfa Bai ◽

Kang Ouyang ◽

...

Keyword(s):

Immune Response ◽

Immune Responses ◽

Innate Immune ◽

Respiratory Syndrome Virus ◽

Adaptive Immune Responses ◽

Virus Growth ◽

Conserved Motif ◽

Adaptive Immune ◽

Infected Cells ◽

Growth Ability

ABSTRACTPorcine reproductive and respiratory syndrome virus (PRRSV) nonstructural protein 1β (nsp1β) is a multifunctional viral protein, which is involved in suppressing the host innate immune response and activating a unique −2/−1 programmed ribosomal frameshifting (PRF) signal for the expression of frameshifting products. In this study, site-directed mutagenesis analysis showed that the R128A or R129A mutation introduced into a highly conserved motif (123GKYLQRRLQ131) reduced the ability of nsp1β to suppress interferon beta (IFN-β) activation and also impaired nsp1β's function as a PRF transactivator. Three recombinant viruses, vR128A, vR129A, and vRR129AA, carrying single or double mutations in the GKYLQRRLQ motif were characterized. In comparison to the wild-type (WT) virus, vR128A and vR129A showed slightly reduced growth abilities, while the vRR129AA mutant had a significantly reduced growth ability in infected cells. Consistent with the attenuated growth phenotypein vitro, pigs infected with nsp1β mutants had lower levels of viremia than did WT virus-infected pigs. Compared to the WT virus in infected cells, all three mutated viruses stimulated high levels of IFN-α expression and exhibited a reduced ability to suppress the mRNA expression of selected interferon-stimulated genes (ISGs). In pigs infected with nsp1β mutants, IFN-α production was increased in the lungs at early time points postinfection, which was correlated with increased innate NK cell function. Furthermore, the augmented innate response was consistent with the increased production of IFN-γ in pigs infected with mutated viruses. These data demonstrate that residues R128 and R129 are critical for nsp1β function and that modifying these key residues in the GKYLQRRLQ motif attenuates virus growth ability and improves the innate and adaptive immune responses in infected animals.IMPORTANCEPRRSV infection induces poor antiviral innate IFN and cytokine responses, which results in weak adaptive immunity. One of the strategies in next-generation vaccine construction is to manipulate viral proteins/genetic elements involved in antagonizing the host immune response. PRRSV nsp1β was identified to be a strong innate immune antagonist. In this study, two basic amino acids, R128 and R129, in a highly conserved GKYLQRRLQ motif were determined to be critical for nsp1β function. Mutations introduced into these two residues attenuated virus growth and improved the innate and adaptive immune responses of infected animals. Technologies developed in this study could be broadly applied to current commercial PRRSV modified live-virus (MLV) vaccines and other candidate vaccines.

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Potential Use of Interleukin-10 Blockade as a Therapeutic Strategy in Human Cutaneous Leishmaniasis

Journal of Immunology Research ◽

10.1155/2015/152741 ◽

2015 ◽

Vol 2015 ◽

pp. 1-5 ◽

Cited By ~ 8

Author(s):

Lucio Roberto Castellano ◽

Laurent Argiro ◽

Helia Dessein ◽

Alain Dessein ◽

Marcos Vinícius da Silva ◽

...

Keyword(s):

Cutaneous Leishmaniasis ◽

Therapeutic Strategy ◽

Interleukin 10 ◽

Leishmania Braziliensis ◽

Soluble Antigen ◽

Innovative Strategies ◽

Host Protection ◽

Human Cutaneous Leishmaniasis ◽

Potential Use ◽

Worse Prognosis

Interleukin-10 overproduction has been associated with worse prognosis in human cutaneous leishmaniasis, while IFN-γ-dependent responses are associated with parasite killing and host protection. Innovative strategies are needed to overcome therapeutic failure observed in endemic areas. The use of monoclonal antibody-based immunotherapy targeting IL-10 cytokine was evaluated here. Partial IL-10 blockade inLeishmania braziliensiswhole soluble antigen-stimulated cells from endemic area CL patients with active or healed lesions and asymptomatic controls was evaluated. Overall decrease in IL-10, IL-4, and TNF-αproduction was observed in all groups of subjects. Only patients with active lesions still produced some levels of TNF-αafter anti-IL-10 stimulation in association withLeishmaniaantigens. Moreover, this strategy showed limited modulatory effects on IFN-γ-dependent chemokine CXCL10 production. Results suggest the potential immunotherapeutic use of partial IL-10 blockade in localized cutaneous leishmaniasis.

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Chemokines and chemokine receptors coordinate the inflammatory immune response in human cutaneous leishmaniasis

Human Immunology ◽

10.1016/j.humimm.2010.09.002 ◽

2010 ◽

Vol 71 (12) ◽

pp. 1220-1227 ◽

Cited By ~ 20

Author(s):

Ana P. Campanelli ◽

Claudia I. Brodskyn ◽

Viviane Boaventura ◽

Claire Silva ◽

Ana M. Roselino ◽

...

Keyword(s):

Immune Response ◽

Cutaneous Leishmaniasis ◽

Chemokine Receptors ◽

Inflammatory Immune Response ◽

Human Cutaneous Leishmaniasis

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B-Aggressive Lymphoma Gene (BAL) Is a Risk-Related, γIFN-Inducible Gene That Is Expressed in Primary Diffuse Large B-Cell Lymphomas with a Brisk Host Inflammatory Response.

Blood ◽

10.1182/blood.v104.11.2035.2035 ◽

2004 ◽

Vol 104 (11) ◽

pp. 2035-2035

Author(s):

Przemyslaw Juszczynski ◽

Jeffery L. Kutok ◽

Ricardo C.T. Aguiar ◽

Joydeep Mitra ◽

Margaret A. Shipp

Keyword(s):

Immune Response ◽

Inflammatory Response ◽

B Cell ◽

Binding Site ◽

B Cell Lymphoma ◽

Host Immune Response ◽

Aggressive Lymphoma ◽

Current Therapy ◽

Host Inflammatory Response ◽

Large B Cell

Abstract Although diffuse large B-cell lymphoma (DLBCL) is potentially curable with current therapy, a significant number of DLBCL patients still die of their disease. In a broad-based screen for genes and pathways associated with poor DLBCL outcome, we previously identified a novel risk-related gene, termed BAL (B-aggressive lymphoma). Thereafter, we cloned and characterized a major BAL partner protein, BBAP (B-aggressive lymphoma and BAL binding partner), described the nuclear trafficking patterns of both proteins and demonstrated that BAL functions as a modulator of transcription. In the current study, we characterized BAL expression in normal tonsil and primary DLBCLs and defined BAL regulation and potential functions in both cell types. Immunohistochemical staining of normal tonsil revealed that BAL was expressed by small numbers of germinal center (GC) cells and interfollicular cells with the morphologic features of centroblasts (with the GC) and immunoblasts (within the interfollicular areas). In primary DLBCLs, BAL was expressed by the malignant B cells. To gain insights regarding the regulation of BAL and BBAP expression in DLBCLs, we analyzed a series of 176 primary tumor biopsies transcriptionally profiled an U133A/B Affymetrix microarrays. BAL/BBAP high-expressing DLBCLs had evidence of a brisk host immune response, including increased expression of T/NK-cell receptor and activation pathway components, complement cascade members, macrophage/dendritic cells markers and γIFN-induced transcripts, raising the possibility that BAL was induced by γIFN. Consistent with this hypothesis, γIFN treatment of DLBCL cell lines with low basal levels of BAL markedly increased BAL expression. In silico analysis revealed that the BAL and BBAP genes are located in 3q21 in head-to-head orientation and share the same CpG-related promoter. This shared promoter contains a conserved γIFN-responsive module composed of IRF and STAT binding elements. The BAL/BBAP bidirectional promoter was cloned into a pGL3 luciferase promoterless reporter vector and found to increase luciferase activity > 20-fold following γIFN stimulation. To gain further insights into regulation of BAL transcription, mutant versions of BAL promoter were generated and cloned. Luciferase assays demonstrated that the IRF binding site was necessary for γIFN-induced BAL transcription, whereas the STAT1 binding site had an accessory role. Taken together, these results demonstrate that BAL and BBAP genes are transcriptionally activated by γIFN in DLBCLs with features of a brisk host immune response including γIFN signaling. Preliminary studies suggest that BAL limits the efficacy of the observed host inflammatory response.

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