scholarly journals Intestinal host defense outcome is dictated by PGE2 production during efferocytosis of infected cells

2018 ◽  
Vol 115 (36) ◽  
pp. E8469-E8478 ◽  
Author(s):  
Naiara Naiana Dejani ◽  
Allan Botinhon Orlando ◽  
Victoria Eugenia Niño ◽  
Letícia de Aquino Penteado ◽  
Felipe Fortino Verdan ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Host Defense ◽  
Inflammatory Responses ◽  
Infectious Colitis ◽  
E Coli ◽  
Ep4 Receptor ◽  
Intestinal Pathology ◽  
Infected Cells ◽  
Th17 Differentiation ◽  
Pka Pathway

Inflammatory responses are terminated by the clearance of dead cells, a process termed efferocytosis. A consequence of efferocytosis is the synthesis of the antiinflammatory mediators TGF-β, PGE2, and IL-10; however, the efferocytosis of infected cells favors Th17 responses by eliciting the synthesis of TGF-β, IL-6, and IL-23. Recently, we showed that the efferocytosis of apoptotic Escherichia coli-infected macrophages by dendritic cells triggers PGE2 production in addition to pro-Th17 cytokine expression. We therefore examined the role of PGE2 during Th17 differentiation and intestinal pathology. The efferocytosis of apoptotic E. coli-infected cells by dendritic cells promoted high levels of PGE2, which impaired IL-1R expression via the EP4-PKA pathway in T cells and consequently inhibited Th17 differentiation. The outcome of murine intestinal Citrobacter rodentium infection was dependent on the EP4 receptor. Infected mice treated with EP4 antagonist showed enhanced intestinal defense against C. rodentium compared with infected mice treated with vehicle control. Those results suggest that EP4 signaling during infectious colitis could be targeted as a way to enhance Th17 immunity and host defense.

Anti-β2 Glycoprotein I Antibodies Cause Inflammation and Recruit Dendritic Cells in Platelet Clearance

2001 ◽  
Vol 86 (11) ◽  
pp. 1257-1263 ◽  
Author(s):  
Attilio Bondanza ◽  
Angelo Manfredi ◽  
Valérie Zimmermann ◽  
Matteo Iannacone ◽  
Angela Tincani ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Inflammatory Responses ◽  
Glycoprotein I ◽  
Activated Platelets ◽  
Tnf Α ◽  
Per Se ◽  
Antigen Presenting ◽  
Antiinflammatory Cytokine

SummaryScavenger phagocytes are mostly responsible for the in vivo clearance of activated or senescent platelets. In contrast to other particulate substrates, the phagocytosis of platelets does not incite pro-inflammatory responses in vivo. This study assessed the contribution of macrophages and dendritic cells (DCs) to the clearance of activated platelets. Furthermore, we verified whether antibodies against the β2 Glycoprotein I (β2GPI), which bind to activated platelets, influence the phenomenon. DCs did not per se internalise activated platelets. In contrast, macrophages efficiently phagocytosed platelets. In agreement with the uneventful nature of the clearance of platelets in vivo, phagocytosing macrophages did not release IL-1β, TNF-α or IL-10. β2GPI bound to activated platelets and was required for their recognition by anti-ββ2GPI antibodies. DCs internalised platelets opsonised by anti-ββ2GPI antibodies. The phagocytosis of opsonised platelets determined the release of TNF-α and IL-1β by DCs and macrophages. Phagocytosing macrophages, but not DCs, secreted the antiinflammatory cytokine IL-1β0. We conclude that anti-ββ2GPI antibodies cause inflammation during platelet clearance and shuttle platelet antigens to antigen presenting DCs.

scholarly journals Human plasmacytoid dendritic cells mount a distinct antiviral response to virus-infected cells

2021 ◽  
Vol 6 (58) ◽  
pp. eabc7302
Author(s):  
Tae Jin Yun ◽  
Suzu Igarashi ◽  
Haoquan Zhao ◽  
Oriana A. Perez ◽  
Marcus R. Pereira ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Virus Detection ◽  
Plasmacytoid Dendritic Cells ◽  
Lung Epithelial Cells ◽  
Live Cells ◽  
Type I ◽  
Antiviral Immune Response ◽  
Lung Epithelial ◽  
Functional Consequences ◽  
Infected Cells

Plasmacytoid dendritic cells (pDCs) can rapidly produce interferons and other soluble factors in response to extracellular viruses or virus mimics such as CpG-containing DNA. pDCs can also recognize live cells infected with certain RNA viruses, but the relevance and functional consequences of such recognition remain unclear. We studied the response of primary DCs to the prototypical persistent DNA virus, human cytomegalovirus (CMV). Human pDCs produced high amounts of type I interferon (IFN-I) when incubated with live CMV-infected fibroblasts but not with free CMV; the response involved integrin-mediated adhesion, transfer of DNA-containing virions to pDCs, and the recognition of DNA through TLR9. Compared with transient polyfunctional responses to CpG or free influenza virus, pDC response to CMV-infected cells was long-lasting, dominated by the production of IFN-I and IFN-III, and lacked diversification into functionally distinct populations. Similarly, pDC activation by influenza-infected lung epithelial cells was highly efficient, prolonged, and dominated by interferon production. Prolonged pDC activation by CMV-infected cells facilitated the activation of natural killer cells critical for CMV control. Last, patients with CMV viremia harbored phenotypically activated pDCs and increased circulating IFN-I and IFN-III. Thus, recognition of live infected cells is a mechanism of virus detection by pDCs that elicits a unique antiviral immune response.

New insights in gut-liver axis in wild-type murine imiquimod-induced lupus

Lupus ◽  
2021 ◽  
Vol 30 (6) ◽  
pp. 926-936
Author(s):  
Georges Maalouly ◽  
Joelle Hajal ◽  
Charbel Noujeim ◽  
Michel Choueiry ◽  
Hussein Nassereddine ◽  
...  
Keyword(s):  
Tight Junction ◽  
Fecal Calprotectin ◽  
Liver Inflammation ◽  
Tight Junction Proteins ◽  
Wild Type ◽  
Imiquimod Cream ◽  
E Coli ◽  
Intestinal Pathology ◽  
Nfκb Pathway ◽  
Junction Proteins

Background Intestinal and hepatic manifestations of lupus seem to be underestimated in comparison to other major organ lesions. Although recent data point to gut-liver axis involvement in lupus, gut permeability dysfunction and liver inflammation need to be more investigated. Objective This study aims to assess fecal calprotectin, intestinal tight junction proteins and liver inflammation pathway in wild-type murine imiquimod- induced lupus. Methods C57BL/6 mice were topically treated on their right ears with 1.25 mg of 5% imiquimod cream, three times per week for six weeks. Fecal calprotectin was collected at day 0, 22 and 45. Renal, liver and intestinal pathology, as well as inflammatory markers, intestinal tight junction proteins, and E. coli protein in liver were assessed at sacrifice. Results At six weeks, lupus nephritis was confirmed on histopathology and NGAL and KIM-1 expression. Calprotectin rise started at day 22 and persists at day 45. Protein expression of Claudine, ZO-1 and occludin was significantly decreased. E. coli protein was significantly increased in liver with necro-inflammation and increased TLR4, TLR7, and pNFκB/NFκB liver expression. Conclusion This study is the first to demonstrate early fecal calprotectin increase and liver activation of TLR4- NFκB pathway in wild-type murine imiquimod-induced lupus.

scholarly journals A Missing Link: Engagements of Dendritic Cells in the Pathogenesis of SARS-CoV-2 Infections

2021 ◽  
Vol 22 (3) ◽  
pp. 1118
Author(s):  
Abdulaziz Alamri ◽  
Derek Fisk ◽  
Deepak Upreti ◽  
Sam K. P. Kung
Keyword(s):  
Dendritic Cells ◽  
Severe Acute Respiratory Syndrome ◽  
Immune Responses ◽  
Immune Cell ◽  
Inflammatory Responses ◽  
Viral Disease ◽  
Cell Recruitment ◽  
Cross Presentation ◽  
Cell Immunity ◽  
Immune Cell Recruitment

Dendritic cells (DC) connect the innate and adaptive arms of the immune system and carry out numerous roles that are significant in the context of viral disease. Their functions include the control of inflammatory responses, the promotion of tolerance, cross-presentation, immune cell recruitment and the production of antiviral cytokines. Based primarily on the available literature that characterizes the behaviour of many DC subsets during Severe acute respiratory syndrome (SARS) and coronavirus disease 2019 (COVID-19), we speculated possible mechanisms through which DC could contribute to COVID-19 immune responses, such as dissemination of Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to lymph nodes, mounting dysfunctional inteferon responses and T cell immunity in patients. We highlighted gaps of knowledge in our understanding of DC in COVID-19 pathogenesis and discussed current pre-clinical development of therapies for COVID-19.

scholarly journals CD4+ CD25+ Foxp3+ Regulatory T Cells, Dendritic Cells, and Circulating Cytokines in Uncomplicated Malaria: Do Different Parasite Species Elicit Similar Host Responses?

2010 ◽  
Vol 78 (11) ◽  
pp. 4763-4772 ◽  
Author(s):  
Raquel M. Gonçalves ◽  
Karina C. Salmazi ◽  
Bianca A. N. Santos ◽  
Melissa S. Bastos ◽  
Sandra C. Rocha ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Parasite Species ◽  
Inflammatory Responses ◽  
Clinical Symptoms ◽  
Clinical Manifestations ◽  
Surface Expression ◽  
Interleukin 10 ◽  
Treg Cells ◽  
Experimental Models ◽  
Necrosis Factor Alpha

ABSTRACT Clearing blood-stage malaria parasites without inducing major host pathology requires a finely tuned balance between pro- and anti-inflammatory responses. The interplay between regulatory T (Treg) cells and dendritic cells (DCs) is one of the key determinants of this balance. Although experimental models have revealed various patterns of Treg cell expansion, DC maturation, and cytokine production according to the infecting malaria parasite species, no studies have compared all of these parameters in human infections with Plasmodium falciparum and P. vivax in the same setting of endemicity. Here we show that during uncomplicated acute malaria, both species induced a significant expansion of CD4+ CD25+ Foxp3+ Treg cells expressing the key immunomodulatory molecule CTLA-4 and a significant increase in the proportion of DCs that were plasmacytoid (CD123+), with a decrease in the myeloid/plasmacytoid DC ratio. These changes were proportional to parasite loads but correlated neither with the intensity of clinical symptoms nor with circulating cytokine levels. One-third of P. vivax-infected patients, but no P. falciparum-infected subjects, showed impaired maturation of circulating DCs, with low surface expression of CD86. Although vivax malaria patients overall had a less inflammatory cytokine response, with a higher interleukin-10 (IL-10)/tumor necrosis factor alpha (TNF-α) ratio, this finding did not translate to milder clinical manifestations than those of falciparum malaria patients. We discuss the potential implications of these findings for species-specific pathogenesis and long-lasting protective immunity to malaria.

scholarly journals Regulatory NLRs Control the RLR-Mediated Type I Interferon and Inflammatory Responses in Human Dendritic Cells

2018 ◽  
Vol 9 ◽  
Author(s):  
Tünde Fekete ◽  
Dora Bencze ◽  
Attila Szabo ◽  
Eszter Csoma ◽  
Tamas Biro ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Inflammatory Responses ◽  
Type I Interferon ◽  
Type I ◽  
Human Dendritic Cells

scholarly journals Combined Action of Human Commensal Bacteria and Amorphous Silica Nanoparticles on the Viability and Immune Responses of Dendritic Cells

2017 ◽  
Vol 24 (10) ◽  
Author(s):  
Giulia Malachin ◽  
Elisa Lubian ◽  
Fabrizio Mancin ◽  
Emanuele Papini ◽  
Regina Tavano
Keyword(s):  
Dendritic Cells ◽  
Silica Nanoparticles ◽  
Amorphous Silica ◽  
Pathogenic Bacteria ◽  
Bacterial Species ◽  
Commensal Bacteria ◽  
Content Type ◽  
E Coli ◽  
Synergistic Induction ◽  
Ifn Γ

ABSTRACT Dendritic cells (DCs) regulate the host-microbe balance in the gut and skin, tissues likely exposed to nanoparticles (NPs) present in drugs, food, and cosmetics. We analyzed the viability and the activation of DCs incubated with extracellular media (EMs) obtained from cultures of commensal bacteria (Escherichia coli, Staphylococcus epidermidis) or pathogenic bacteria (Pseudomonas aeruginosa, Staphylococcus aureus) in the presence of amorphous silica nanoparticles (SiO2 NPs). EMs and NPs synergistically increased the levels of cytotoxicity and cytokine production, with different nanoparticle dose-response characteristics being found, depending on the bacterial species. E. coli and S. epidermidis EMs plus NPs at nontoxic doses stimulated the secretion of interleukin-1β (IL-1β), IL-12, IL-10, and IL-6, while E. coli and S. epidermidis EMs plus NPs at toxic doses stimulated the secretion of gamma interferon (IFN-γ), tumor necrosis factor alpha (TNF-α), IL-4, and IL-5. On the contrary, S. aureus and P. aeruginosa EMs induced cytokines only when they were combined with NPs at toxic concentrations. The induction of maturation markers (CD86, CD80, CD83, intercellular adhesion molecule 1, and major histocompatibility complex class II) by commensal bacteria but not by pathogenic ones was improved in the presence of noncytotoxic SiO2 NP doses. DCs consistently supported the proliferation and differentiation of CD4+ and CD8+ T cells secreting IFN-γ and IL-17A. The synergistic induction of CD86 was due to nonprotein molecules present in the EMs from all bacteria tested. At variance with this finding, the synergistic induction of IL-1β was prevalently mediated by proteins in the case of E. coli EMs and by nonproteins in the case of S. epidermidis EMs. A bacterial costimulus did not act on DCs after adsorption on SiO2 NPs but rather acted as an independent agonist. The inflammatory and immune actions of DCs stimulated by commensal bacterial agonists might be altered by the simultaneous exposure to engineered or environmental NPs.

scholarly journals Protective Roles of γδ T Cells and Interleukin-15 in Escherichia coli Infection in Mice

1998 ◽  
Vol 66 (7) ◽  
pp. 3270-3278 ◽  
Author(s):  
M. Takano ◽  
H. Nishimura ◽  
Y. Kimura ◽  
Y. Mokuno ◽  
J. Washizu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Monoclonal Antibody ◽  
T Cells ◽  
T Cell Receptor ◽  
Host Defense ◽  
Γδ T Cells ◽  
Cell Receptor ◽  
E Coli ◽  
Escherichia Coli Infection ◽  
Interleukin 15

The number of γδ T cells in the peritoneal cavity was increased after an intraperitoneal (i.p.) infection with Escherichia coli in lipopolysaccharide (LPS)-responsive C3H/HeN mice but not in LPS-hyporesponsive C3H/HeJ mice. The γδ T cells preferentially expressed invariant Vγ6 and Vδ1 chains and proliferated to produce a large amount of gamma interferon in the presence of LPS. Mice depleted of γδ T cells by T-cell receptor δ gene mutation showed impaired resistance against E. coli as assessed by bacterial growth. Macrophages from C3H/HeN mice infected with E. coli expressed higher levels of interleukin-15 (IL-15) mRNA than those from the infected C3H/HeJ mice. Administration of anti-IL-15 monoclonal antibody inhibited, albeit partially, the appearance of γδ T cells in C3H/HeN mice after E. coli infection and diminished the host defense against the infection. These results suggest that LPS-stimulated γδ T cells play an important role in the host defense against E. coli infection and that IL-15 may be partly involved in the protection via an increase in the γδ T cells.

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