scholarly journals Matrix lumican endocytosed by immune cells controls receptor ligand trafficking to promote TLR4 and restrict TLR9 in sepsis

2021 ◽  
Vol 118 (27) ◽  
pp. e2100999118
Author(s):  
George Maiti ◽  
Jihane Frikeche ◽  
Carly Yuen-Man Lam ◽  
Asim Biswas ◽  
Vishal Shinde ◽  
...  
Keyword(s):  
Cell Surface ◽  
Immune Cells ◽  
Immune Cell ◽  
De Novo ◽  
Body Weight Loss ◽  
Type I Interferons ◽  
Type I ◽  
Cpg Dna ◽  
Ecm Remodeling

Infections and inflammation are profoundly influenced by the extracellular matrix (ECM), but their molecular underpinnings are ill defined. Here, we demonstrate that lumican, an ECM protein normally associated with collagens, is elevated in sepsis patients’ blood, while lumican-null mice resolve polymicrobial sepsis poorly, with reduced bacterial clearance and greater body weight loss. Secreted by activated fibroblasts, lumican promotes Toll-like receptor (TLR) 4 response to bacterial lipopolysaccharides (LPS) but restricts nucleic acid–specific TLR9 in macrophages and dendritic cells. The underlying mechanism involves lumican attachment to the common TLR coreceptor CD14 and caveolin 1 (Cav1) in lipid rafts on immune cell surfaces via two epitopes, which may be cryptic in collagen-associated lumican. The Cav1 binding epitope alone is sufficient for cell surface enrichment of Cav1, while both are required for lumican to increase cell surface TLR4, CD14, and proinflammatory cytokines in response to LPS. Endocytosed lumican colocalizes with TLR4 and LPS and promotes endosomal induction of type I interferons. Lumican-null macrophages show elevated TLR9 in signal-permissive endolysosomes and increased response, while wild types show lumican colocalization with CpG DNA but not TLR9, consistent with a ligand sequestering, restrictive role for lumican in TLR9 signaling. In vitro, lumican competes with CD14 to bind CpG DNA; biglycan, a lumican paralog, also binds CpG DNA and suppresses TLR9 response. Thus, lumican and other ECM proteins, synthesized de novo or released from collagen association during ECM remodeling, may be internalized by immune cells to regulate their transcriptional programs and effector responses that may be harnessed in future therapeutics.

scholarly journals Type I Interferon-mediated Stimulation of T Cells by CpG DNA

1998 ◽  
Vol 188 (12) ◽  
pp. 2335-2342 ◽  
Author(s):  
Siquan Sun ◽  
Xiaohong Zhang ◽  
David F. Tough ◽  
Jonathan Sprent
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Type I Interferons ◽  
Type I ◽  
Cpg Dna ◽  
Stimulation Of

Immunostimulatory DNA and oligodeoxynucleotides containing unmethylated CpG motifs (CpG DNA) are strongly stimulatory for B cells and antigen-presenting cells (APCs). We report here that, as manifested by CD69 and B7-2 upregulation, CpG DNA also induces partial activation of T cells, including naive-phenotype T cells, both in vivo and in vitro. Under in vitro conditions, CpG DNA caused activation of T cells in spleen cell suspensions but failed to stimulate highly purified T cells unless these cells were supplemented with APCs. Three lines of evidence suggested that APC-dependent stimulation of T cells by CpG DNA was mediated by type I interferons (IFN-I). First, T cell activation by CpG DNA was undetectable in IFN-IR−/− mice. Second, in contrast to normal T cells, the failure of purified IFN-IR−/− T cells to respond to CpG DNA could not be overcome by adding normal IFN-IR+ APCs. Third, IFN-I (but not IFN-γ) caused the same pattern of partial T cell activation as CpG DNA. Significantly, T cell activation by IFN-I was APC independent. Thus, CpG DNA appeared to stimulate T cells by inducing APCs to synthesize IFN-I, which then acted directly on T cells via IFN-IR. Functional studies suggested that activation of T cells by IFN-I was inhibitory. Thus, exposing normal (but not IFN-IR−/−) T cells to CpG DNA in vivo led to reduced T proliferative responses after TCR ligation in vitro.

scholarly journals Type-I Interferon Receptor Deficiency Reduces Lupus-like Disease in NZB Mice

2003 ◽  
Vol 197 (6) ◽  
pp. 777-788 ◽  
Author(s):  
Marie-Laure Santiago-Raber ◽  
Roberto Baccala ◽  
Katarina M. Haraldsson ◽  
Divaker Choubey ◽  
Timothy A. Stewart ◽  
...  
Keyword(s):  
T Cell ◽  
Immune Cell ◽  
Indirect Evidence ◽  
Dendritic Cell Maturation ◽  
Type I Interferons ◽  
Type I ◽  
Type I Ifns ◽  
Common Receptor

Indirect evidence suggests that type-I interferons (IFN-α/β) play a significant role in the pathogenesis of lupus. To directly examine the contribution of these pleiotropic molecules, we created congenic NZB mice lacking the α-chain of IFN-α/βR, the common receptor for the multiple IFN-α/β species. Compared with littermate controls, homozygous IFN-α/βR-deleted NZB mice had significantly reduced anti-erythrocyte autoantibodies, erythroblastosis, hemolytic anemia, anti-DNA autoantibodies, kidney disease, and mortality. These reductions were intermediate in the heterozygous-deleted mice. The disease-ameliorating effects were accompanied by reductions in splenomegaly and in several immune cell subsets, including B-1 cells, the major producers of anti-erythrocyte autoantibodies. Decreases of B and T cell proliferation in vitro and in vivo, and of dendritic cell maturation and T cell stimulatory activity in vitro were also detected. Absence of signaling through the IFN-α/βR, however, did not affect increased basal levels of the IFN-responsive p202 phosphoprotein, encoded by a polymorphic variant of the Ifi202 gene associated with the Nba2 predisposing locus in NZB mice. The data indicate that type-I IFNs are important mediators in the pathogenesis of murine lupus, and that reducing their activity in the human counterpart may be beneficial.

scholarly journals Human Immunodeficiency Virus Viremia Induces Plasmacytoid Dendritic Cell Activation In Vivo and Diminished Alpha Interferon Production In Vitro

2008 ◽  
Vol 82 (8) ◽  
pp. 3997-4006 ◽  
Author(s):  
John C. Tilton ◽  
Maura M. Manion ◽  
Marlise R. Luskin ◽  
Alison J. Johnson ◽  
Andy A. Patamawenu ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
De Novo ◽  
Type I Interferons ◽  
Type I ◽  
Interferon Production ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) infection has been associated with perturbations of plasmacytoid dendritic cells (PDC), including diminished frequencies in the peripheral blood and reduced production of type I interferons (IFNs) in response to in vitro stimulation. However, recent data suggest a paradoxical increase in production of type 1 interferons in vivo in HIV-infected patients compared to uninfected controls. Using a flow cytometric assay to detect IFN-α-producing cells within unseparated peripheral blood mononuclear cells, we observed that short-term interruptions of antiretroviral therapy are sufficient to result in significantly reduced IFN-α production by PDC in vitro in response to CpG A ligands or inactivated HIV particles. The primary cause of diminished IFN-α production was reduced responsiveness of PDC to de novo stimulation, not diminished per cell IFN-α production or migration of cells to lymphoid organs. Real-time PCR analysis of purified PDC from patients prior to and during treatment interruptions revealed that active HIV-1 replication is associated with upregulation of type I IFN-stimulated gene expression. Treatment of hepatitis C virus-infected patients with IFN-α2b and ribavirin for hepatitis C virus infection resulted in a profound suppression of de novo IFN-α production in response to CpG A or inactivated HIV particles, similar to the response observed in HIV-infected patients. Together, these results suggest that diminished production of type I interferons in vitro by PDC from HIV-1-infected patients may not represent diminished interferon production in vivo. Rather, diminished function in vitro is likely a consequence of prior activation via type I interferons or HIV virions in vivo.

Albumin internalizes and inhibits endosomal TLR signaling in leukocytes from patients with decompensated cirrhosis

2020 ◽  
Vol 12 (566) ◽  
pp. eaax5135 ◽  
Author(s):  
Mireia Casulleras ◽  
Roger Flores-Costa ◽  
Marta Duran-Güell ◽  
José Alcaraz-Quiles ◽  
Silvia Sanz ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Immune Cell ◽  
Human Albumin ◽  
Decompensated Cirrhosis ◽  
Type I ◽  
Tlr Signaling ◽  
Cpg Dna ◽  
Cell Transcriptome

Human serum albumin (HSA) is an emerging treatment for preventing excessive systemic inflammation and organ failure(s) in patients with acutely decompensated (AD) cirrhosis. Here, we investigated the molecular mechanisms underlying the immunomodulatory properties of HSA. Administration of HSA to patients with AD cirrhosis with elevated circulating bacterial DNA rich in unmethylated cytosine-phosphate-guanine dideoxynucleotide motifs (CpG-DNA) was associated with reduced plasma cytokine concentrations. In isolated leukocytes, HSA abolished CpG-DNA–induced cytokine expression and release independently of its oncotic and scavenging properties. Similar anti-inflammatory effects were observed with recombinant human albumin. HSA exerted widespread changes on the immune cell transcriptome, specifically in genes related to cytokines and type I interferon responses. Our data revealed that HSA was taken up by leukocytes and internalized in vesicles positively stained with early endosome antigen 1 and colocalized with CpG-DNA in endosomes, where the latter binds to Toll-like receptor 9 (TLR9), its cognate receptor. Furthermore, HSA also inhibited polyinosinic:polycytidylic acid– and lipopolysaccharide-induced interferon regulatory factor 3 phosphorylation and TIR domain–containing adapter-inducing interferon-β–mediated responses, which are exclusive of endosomal TLR3 and TLR4 signaling, respectively. The immunomodulatory actions of HSA did not compromise leukocyte defensive mechanisms such as phagocytosis, efferocytosis, and intracellular reactive oxygen species production. The in vitro immunomodulatory effects of HSA were confirmed in vivo in analbuminemic humanized neonatal Fc receptor transgenic mice. These findings indicate that HSA internalizes in immune cells and modulates their responses through interaction with endosomal TLR signaling, thus providing a mechanism for the benefits of HSA infusions in patients with cirrhosis.

Type I Interferons promote maintenance and function of follicular T helper cells in vitro

2019 ◽  
Author(s):  
S Ehrlich ◽  
K Wild ◽  
M Smits ◽  
K Zoldan ◽  
M Hofmann ◽  
...  
Keyword(s):  
T Helper Cells ◽  
Type I Interferons ◽  
Type I ◽  
T Helper ◽  
Helper Cells ◽  
Follicular T Helper Cells ◽  
And Function

scholarly journals In Vitro Evaluation of CD276-CAR NK-92 Functionality, Migration and Invasion Potential in the Presence of Immune Inhibitory Factors of the Tumor Microenvironment

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1020
Author(s):  
Stefan Grote ◽  
Guillermo Ureña-Bailén ◽  
Kenneth Chun-Ho Chan ◽  
Caroline Baden ◽  
Markus Mezger ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Solid Tumors ◽  
Immune Cells ◽  
Immune Cell ◽  
Nk Cell ◽  
Migration And Invasion ◽  
Cellular Immunotherapy ◽  
Knock Out ◽  
Immunosuppressive Tumor Microenvironment

Background: Melanoma is the most lethal of all skin-related cancers with incidences continuously rising. Novel therapeutic approaches are urgently needed, especially for the treatment of metastasizing or therapy-resistant melanoma. CAR-modified immune cells have shown excellent results in treating hematological malignancies and might represent a new treatment strategy for refractory melanoma. However, solid tumors pose some obstacles for cellular immunotherapy, including the identification of tumor-specific target antigens, insufficient homing and infiltration of immune cells as well as immune cell dysfunction in the immunosuppressive tumor microenvironment (TME). Methods: In order to investigate whether CAR NK cell-based immunotherapy can overcome the obstacles posed by the TME in melanoma, we generated CAR NK-92 cells targeting CD276 (B7-H3) which is abundantly expressed in solid tumors, including melanoma, and tested their effectivity in vitro in the presence of low pH, hypoxia and other known factors of the TME influencing anti-tumor responses. Moreover, the CRISPR/Cas9-induced disruption of the inhibitory receptor NKG2A was assessed for its potential enhancement of NK-92-mediated anti-tumor activity. Results: CD276-CAR NK-92 cells induced specific cytolysis of melanoma cell lines while being able to overcome a variety of the immunosuppressive effects normally exerted by the TME. NKG2A knock-out did not further improve CAR NK-92 cell-mediated cytotoxicity. Conclusions: The strong cytotoxic effect of a CD276-specific CAR in combination with an “off-the-shelf” NK-92 cell line not being impaired by some of the most prominent negative factors of the TME make CD276-CAR NK-92 cells a promising cellular product for the treatment of melanoma and beyond.

scholarly journals HIV-Infected Macrophages Are Infected and Killed by the Interferon-Sensitive Rhabdovirus MG1

2021 ◽  
Vol 95 (9) ◽  
Author(s):  
Teslin S. Sandstrom ◽  
Nischal Ranganath ◽  
Stephanie C. Burke Schinkel ◽  
Syim Salahuddin ◽  
Oussama Meziane ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Oncolytic Viruses ◽  
Type I Interferons ◽  
Viral Reservoir ◽  
Type I ◽  
Antiviral Signaling ◽  
Infected Cells ◽  
Hiv 1

ABSTRACT The use of unique cell surface markers to target and eradicate HIV-infected cells has been a longstanding objective of HIV-1 cure research. This approach, however, overlooks the possibility that intracellular changes present within HIV-infected cells may serve as valuable therapeutic targets. For example, the identification of dysregulated antiviral signaling in cancer has led to the characterization of oncolytic viruses capable of preferentially killing cancer cells. Since impairment of cellular antiviral machinery has been proposed as a mechanism by which HIV-1 evades immune clearance, we hypothesized that HIV-infected macrophages (an important viral reservoir in vivo) would be preferentially killed by the interferon-sensitive oncolytic Maraba virus MG1. We first showed that HIV-infected monocyte-derived macrophages (MDM) were more susceptible to MG1 infection and killing than HIV-uninfected cells. As MG1 is highly sensitive to type I interferons (IFN-I), we then investigated whether we could identify IFN-I signaling differences between HIV-infected and uninfected MDM and found evidence of impaired IFN-α responsiveness within HIV-infected cells. Finally, to assess whether MG1 could target a relevant, primary cell reservoir of HIV-1, we investigated its effects in alveolar macrophages (AM) obtained from effectively treated individuals living with HIV-1. As observed with in vitro-infected MDM, we found that HIV-infected AM were preferentially eliminated by MG1. In summary, the oncolytic rhabdovirus MG1 appears to preferentially target and kill HIV-infected cells via impairment of antiviral signaling pathways and may therefore provide a novel approach to an HIV-1 cure. IMPORTANCE Human immunodeficiency virus type 1 (HIV-1) remains a treatable, but incurable, viral infection. The establishment of viral reservoirs containing latently infected cells remains the main obstacle in the search for a cure. Cure research has also focused on only one cellular target of HIV-1 (the CD4+ T cell) while largely overlooking others (such as macrophages) that contribute to HIV-1 persistence. In this study, we address these challenges by describing a potential strategy for the eradication of HIV-infected macrophages. Specifically, we show that an engineered rhabdovirus—initially developed as a cancer therapy—is capable of preferential infection and killing of HIV-infected macrophages, possibly via the same altered antiviral signaling seen in cancer cells. As this rhabdovirus is currently being explored in phase I/II clinical trials, there is potential for this approach to be readily adapted for use within the HIV-1 cure field.

scholarly journals Mechanisms Of Organelle Identity and Adaptation In Immune Cells

2021 ◽  
Author(s):  
Victoria Emily Barbosa Hipolito
Keyword(s):  
Immune Cells ◽  
Antigen Processing ◽  
Immune Cell ◽  
De Novo ◽  
Scale Up ◽  
Mrna Translation ◽  
Class Iii ◽  
Spatiotemporal Resolution ◽  
Lysosome Biogenesis ◽  
Phosphatidylinositol 3

Cells are exposed to diverse extracellular and intracellular cues, and coopt subcellular responses depending on their cellular state and functional demand; including upregulating signalling pathways or adapting organelle function and physiology. The immune system is a tightly regulated cohort of specialized cells with heterogeneous functions. Phagocytes, a type of immune cell, are challenged with disparate environmental stimuli and can adapt intracellularly to promote immunity. Due to their cellular plasticity, we aim to understand the molecular machinery that controls organelle identity and adaptation in immune cells, when challenged with immunostimulatory agents. First, we used a long tubular phagocytic cup, which provides the spatiotemporal resolution necessary to study the stages of phagocytosis. Using this model, we observed the sequential recruitment of early and late endolysosomal markers to the growing cup. Surprisingly, the early endosomal lipid, phosphatidylinositol-3-phosphate [PtdIns(3)P] persisted. We determined a novel pH-based mechanism that induces the dissociation of the Vps34 Class III phosphatidylinositol-3- kinase from tubular cups as they progressively acidify, when reaching 20 µm in length or upon phagosome closure. The detachment of Vps34 stops the production of PtdIns(3)P, allowing for its turnover by PIKfyve. Given that PtdIns(3)P dependent signalling is important for multiple cellular pathways, this mechanism for pH-dependent regulation of Vps34 could be at the center of many PtdIns(3)P-dependent cellular processes. Additionally, we examined how lysosomes, a kingpin organelle essential for pathogen killing, and antigen processing and presentation, adapt in response to phagocyte activation. During phagocyte activation, lysosomes are remodelled from dozens of globular structures to a tubular network, in a process that requires the PI3K-AKT-mTOR signalling pathway. We showed that lysosome tubulation is coupled with an increase in volume and holding capacity. Lysosome remodelling was dependent on de novo synthesis of lysosomal proteins, but independent of TFEB and TFE3 transcription factors, known to scale-up lysosome biogenesis. We demonstrate a novel mechanism of acute organelle expansion via mTORC1-S6K-4E-BP-dependent increase in lysosomal mRNA translation. This process was necessary for efficient and rapid antigen presentation to T-cells by dendritic cells (DCs). Moreover, lysosome remodelling was conserved in DCs activated with select adjuvants, additives used in vaccines to boost efficacy, providing evidence for its possible clinical applicability. Together, we have identified two novel mechanisms controlling organelle identity and adaptation in immune cells.

scholarly journals Mechanisms Of Organelle Identity and Adaptation In Immune Cells

2021 ◽  
Author(s):  
Victoria Emily Barbosa Hipolito
Keyword(s):  
Immune Cells ◽  
Antigen Processing ◽  
Immune Cell ◽  
De Novo ◽  
Scale Up ◽  
Mrna Translation ◽  
Class Iii ◽  
Spatiotemporal Resolution ◽  
Lysosome Biogenesis ◽  
Phosphatidylinositol 3

Cells are exposed to diverse extracellular and intracellular cues, and coopt subcellular responses depending on their cellular state and functional demand; including upregulating signalling pathways or adapting organelle function and physiology. The immune system is a tightly regulated cohort of specialized cells with heterogeneous functions. Phagocytes, a type of immune cell, are challenged with disparate environmental stimuli and can adapt intracellularly to promote immunity. Due to their cellular plasticity, we aim to understand the molecular machinery that controls organelle identity and adaptation in immune cells, when challenged with immunostimulatory agents. First, we used a long tubular phagocytic cup, which provides the spatiotemporal resolution necessary to study the stages of phagocytosis. Using this model, we observed the sequential recruitment of early and late endolysosomal markers to the growing cup. Surprisingly, the early endosomal lipid, phosphatidylinositol-3-phosphate [PtdIns(3)P] persisted. We determined a novel pH-based mechanism that induces the dissociation of the Vps34 Class III phosphatidylinositol-3- kinase from tubular cups as they progressively acidify, when reaching 20 µm in length or upon phagosome closure. The detachment of Vps34 stops the production of PtdIns(3)P, allowing for its turnover by PIKfyve. Given that PtdIns(3)P dependent signalling is important for multiple cellular pathways, this mechanism for pH-dependent regulation of Vps34 could be at the center of many PtdIns(3)P-dependent cellular processes. Additionally, we examined how lysosomes, a kingpin organelle essential for pathogen killing, and antigen processing and presentation, adapt in response to phagocyte activation. During phagocyte activation, lysosomes are remodelled from dozens of globular structures to a tubular network, in a process that requires the PI3K-AKT-mTOR signalling pathway. We showed that lysosome tubulation is coupled with an increase in volume and holding capacity. Lysosome remodelling was dependent on de novo synthesis of lysosomal proteins, but independent of TFEB and TFE3 transcription factors, known to scale-up lysosome biogenesis. We demonstrate a novel mechanism of acute organelle expansion via mTORC1-S6K-4E-BP-dependent increase in lysosomal mRNA translation. This process was necessary for efficient and rapid antigen presentation to T-cells by dendritic cells (DCs). Moreover, lysosome remodelling was conserved in DCs activated with select adjuvants, additives used in vaccines to boost efficacy, providing evidence for its possible clinical applicability. Together, we have identified two novel mechanisms controlling organelle identity and adaptation in immune cells.

scholarly journals A host type I interferon response is induced by cytosolic sensing of the bacterial second messenger cyclic-di-GMP

2009 ◽  
Vol 206 (9) ◽  
pp. 1899-1911 ◽  
Author(s):  
Sarah M. McWhirter ◽  
Roman Barbalat ◽  
Kathryn M. Monroe ◽  
Mary F. Fontana ◽  
Mamoru Hyodo ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Map Kinases ◽  
Second Messenger ◽  
Innate Immune ◽  
Guanosine Monophosphate ◽  
Host Cells ◽  
Type I Interferons ◽  
Interferon Response ◽  
Type I

The innate immune system responds to unique molecular signatures that are widely conserved among microbes but that are not normally present in host cells. Compounds that stimulate innate immune pathways may be valuable in the design of novel adjuvants, vaccines, and other immunotherapeutics. The cyclic dinucleotide cyclic-di–guanosine monophosphate (c-di-GMP) is a recently appreciated second messenger that plays critical regulatory roles in many species of bacteria but is not produced by eukaryotic cells. In vivo and in vitro studies have previously suggested that c-di-GMP is a potent immunostimulatory compound recognized by mouse and human cells. We provide evidence that c-di-GMP is sensed in the cytosol of mammalian cells via a novel immunosurveillance pathway. The potency of cytosolic signaling induced by c-di-GMP is comparable to that induced by cytosolic delivery of DNA, and both nucleic acids induce a similar transcriptional profile, including triggering of type I interferons and coregulated genes via induction of TBK1, IRF3, nuclear factor κB, and MAP kinases. However, the cytosolic pathway that senses c-di-GMP appears to be distinct from all known nucleic acid–sensing pathways. Our results suggest a novel mechanism by which host cells can induce an inflammatory response to a widely produced bacterial ligand.

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