144 results found
Childs E, Henry CM, Canton J, et al., 2021, Maintenance and loss of endocytic organelle integrity: mechanisms and implications for antigen cross-presentation, OPEN BIOLOGY, Vol: 11
Stok JE, Oosenbrug T, ter Haar LR, et al., 2021, RNA sensing via LGP2 is essential for the induction of a type I IFN response in ADAR1 deficiency
<jats:title>Abstract</jats:title><jats:p>RNA editing by the enzyme Adenosine Deaminase Acting on RNA 1 (ADAR1) is an important mechanism by which cells avoid innate immune responses to some endogenous RNAs. In ADAR1-deficient cells, unedited self RNAs can form base-paired structures that resemble viral RNAs and inadvertently activate antiviral innate immune pathways that lead to the induction of type I interferon (IFN). Rare mutations in ADAR1 cause Aicardi-Goutières Syndrome (AGS), a severe childhood autoinflammatory syndrome that is characterized by chronic and excessive type I IFN production and developmental delay. Conversely, ADAR1 dysfunction and consequent type I IFN production helps restrict tumor growth and potentiates the activity of some chemotherapy drugs. Induction of type I IFN in ADAR1-deficient cells is thought to be due to triggering of the cytosolic RIG-I-like receptor (RLR), MDA5, by unedited self RNAs. Here, we show that another RLR, LGP2, also has an essential role. We demonstrate that ADAR1-deficient human cells fail to mount a type I IFN response in the absence of LGP2 and this involves the canonical function of LGP2 as an RNA sensor and facilitator of MDA5-dependent signaling. Further, we show that the sensitivity of tumor cells to ADAR1 loss requires the presence of LGP2. Finally, we find that type I IFN induction in tumor cells depleted of ADAR1 and treated with some chemotherapeutics is fully dependent on the expression of LGP2. These findings highlight a central role for LGP2 in self RNA sensing with important clinical implications for the treatment of AGS as well as for the potential application of ADAR1-directed anti-tumor therapy.</jats:p>
Poirier EZ, Buck MD, Chakravarty P, et al., 2021, An isoform of Dicer protects mammalian stem cells against multiple RNA viruses, SCIENCE, Vol: 373, Pages: 231-+, ISSN: 0036-8075
Buck MD, Poirier EZ, Cardoso A, et al., 2021, SARS-CoV-2 detection by a clinical diagnostic RT-LAMP assay [version 1; peer review: 2 approved with reservations], Wellcome Open Research, Vol: 6, Pages: 1-29
Abstract The ongoing pandemic of SARS-CoV-2 calls for rapid and cost-effective methods to accurately identify infected individuals. The vast majority of patient samples is assessed for viral RNA presence by RT-qPCR. Our biomedical research institute, in collaboration between partner hospitals and an accredited clinical diagnostic laboratory, established a diagnostic testing pipeline that has reported on more than 252,000 RT-qPCR results since its commencement at the beginning of April 2020. However, due to ongoing demand and competition for critical resources, alternative testing strategies were sought. In this work, we present a clinically-validated procedure for high-throughput SARSCoV-2 detection by RT-LAMP in 25 minutes that is robust, reliable, repeatable, sensitive, specific, and inexpensive
Buck MD, Poirier EZ, Cardoso A, et al., 2021, SARS-CoV-2 detection by a clinical diagnostic RT-LAMP assay., Wellcome Open Res, Vol: 6, ISSN: 2398-502X
The ongoing pandemic of SARS-CoV-2 calls for rapid and cost-effective methods to accurately identify infected individuals. The vast majority of patient samples is assessed for viral RNA presence by RT-qPCR. Our biomedical research institute, in collaboration between partner hospitals and an accredited clinical diagnostic laboratory, established a diagnostic testing pipeline that has reported on more than 252,000 RT-qPCR results since its commencement at the beginning of April 2020. However, due to ongoing demand and competition for critical resources, alternative testing strategies were sought. In this work, we present a clinically-validated procedure for high-throughput SARS-CoV-2 detection by RT-LAMP that is robust, reliable, repeatable, specific, and inexpensive.
Gordon O, Reis e Sousa C, 2019, Cytoskeletal Exposure in the Regulation of Immunity and Initiation of Tissue Repair, BIOESSAYS, Vol: 41, ISSN: 0265-9247
Maillard PV, van der Veen AG, Poirier EZ, et al., 2019, Slicing and dicing viruses: antiviral RNA interference in mammals, EMBO JOURNAL, Vol: 38, ISSN: 0261-4189
Cabeza-Cabrerizo M, van Blijswijk J, Wienert S, et al., 2019, Tissue clonality of dendritic cell subsets and emergency DCpoiesis revealed by multicolor fate mapping of DC progenitors, SCIENCE IMMUNOLOGY, Vol: 4, ISSN: 2470-9468
Rosa FF, Pires CF, Kurochkin I, et al., 2018, Direct reprogramming of fibroblasts into antigen-presenting dendritic cells, SCIENCE IMMUNOLOGY, Vol: 3, ISSN: 2470-9468
Whitney PG, Bar E, Osorio F, et al., 2018, Syk Signaling in Dendritic Cells Orchestrates Innate Resistance to Systemic Fungal Infection (vol 10, e1004276, 2014), PLOS PATHOGENS, Vol: 14, ISSN: 1553-7366
Boettcher JP, Reis e Sousa C, 2018, The Role of Type 1 Conventional Dendritic Cells in Cancer Immunity, TRENDS IN CANCER, Vol: 4, Pages: 784-792, ISSN: 2405-8025
Gordon O, Henry CM, Srinivasan N, et al., 2018, alpha-actinin accounts for the bioactivity of actin preparations in inducing STAT target genes in Drosophila melanogaster, eLife, Vol: 7, ISSN: 2050-084X
Damage-associated molecular patterns (DAMPs) are molecules exposed or released bydead cells that trigger or modulate immunity and tissue repair. In vertebrates, the cytoskeletalcomponent F-actin is a DAMP specifically recognised by DNGR-1, an innate immune receptor.Previously we suggested that actin is also a DAMP in Drosophila melanogaster by inducing STATdependent genes (Srinivasan et al., 2016). Here, we revise that conclusion and report that aactinin is far more potent than actin at inducing the same STAT response and can be found in traceamounts in actin preparations. Recombinant expression of actin or a-actinin in bacteriademonstrated that only a-actinin could drive the expression of STAT target genes in Drosophila.The response to injected a-actinin required the same signalling cascade that we had identified inour previous work using actin preparations. Taken together, these data indicate that a-actininrather than actin drives STAT activation when injected into Drosophila.
Schulz O, Hanč P, Böttcher JP, et al., 2018, Myosin II synergizes with F-actin to promote DNGR-1-dependent cross-presentation of dead cell-associated antigens, Cell Reports, Vol: 24, Pages: 419-428, ISSN: 2211-1247
Conventional type 1 DCs (cDC1s) excel at cross-presentation of dead cell-associated antigens partly because they express DNGR-1, a receptor that recognizes exposed actin filaments on dead cells. In vitro polymerized F-actin can be used as a synthetic ligand for DNGR-1. However, cellular F-actin is decorated with actin-binding proteins, which could affect DNGR-1 recognition. Here, we demonstrate that myosin II, an F-actin-associated motor protein, greatly potentiates the binding of DNGR-1 to F-actin. Latex beads coated with F-actin and myosin II are taken up by DNGR-1+ cDC1s, and antigen associated with those beads is efficiently cross-presented to CD8+ T cells. Myosin II-deficient necrotic cells are impaired in their ability to stimulate DNGR-1 or to serve as substrates for cDC1 cross-presentation to CD8+ T cells. These results provide insights into the nature of the DNGR-1 ligand and have implications for understanding immune responses to cell-associated antigens and for vaccine design.
Koliopoulos MG, Lethier M, van der Veen AG, et al., 2018, Molecular mechanism of influenza A NS1-mediated TRIM25 recognition and inhibition, Nature Communications, Vol: 9, ISSN: 2041-1723
RIG-I is a viral RNA sensor that induces the production of type I interferon (IFN) in response to infection with a variety of viruses. Modification of RIG-I with K63-linked poly-ubiquitin chains, synthesised by TRIM25, is crucial for activation of the RIG-I/MAVS signalling pathway. TRIM25 activity is targeted by influenza A virus non-structural protein 1 (NS1) to suppress IFN production and prevent an efficient host immune response. Here we present structures of the human TRIM25 coiled-coil-PRYSPRY module and of complexes between the TRIM25 coiled-coil domain and NS1. These structures show that binding of NS1 interferes with the correct positioning of the PRYSPRY domain of TRIM25 required for substrate ubiquitination and provide a mechanistic explanation for how NS1 suppresses RIG-I ubiquitination and hence downstream signalling. In contrast, the formation of unanchored K63-linked poly-ubiquitin chains is unchanged by NS1 binding, indicating that RING dimerisation of TRIM25 is not affected by NS1.
Salvermoser J, van Blijswijk J, Papaioannou NE, et al., 2018, Clec9a-mediated ablation of conventional dendritic cells suggests a lymphoid path to generating dendritic cells In Vivo, Frontiers in Immunology, Vol: 9, ISSN: 1664-3224
Conventional dendritic cells (cDCs) are versatile activators of immune responses that develop as part of the myeloid lineage downstream of hematopoietic stem cells. We have recently shown that in mice precursors of cDCs, but not of other leukocytes, are marked by expression of DNGR-1/CLEC9A. To genetically deplete DNGR-1-expressing cDC precursors and their progeny, we crossed Clec9a-Cre mice to Rosa-lox-STOP-lox-diphtheria toxin (DTA) mice. These mice develop signs of age-dependent myeloproliferative disease, as has been observed in other DC-deficient mouse models. However, despite efficient depletion of cDC progenitors in these mice, cells with phenotypic characteristics of cDCs populate the spleen. These cells are functionally and transcriptionally similar to cDCs in wild type control mice but show somatic rearrangements of Ig-heavy chain genes, characteristic of lymphoid origin cells. Our studies reveal a previously unappreciated developmental heterogeneity of cDCs and suggest that the lymphoid lineage can generate cells with features of cDCs when myeloid cDC progenitors are impaired.
Boettcher JP, Bonavita E, Chakravarty P, et al., 2018, NK cells stimulate recruitment of cDC1 into the tumor microenvironment promoting cancer immune control, Cell, Vol: 172, Pages: 1022-1037.e14, ISSN: 0092-8674
Conventional type 1 dendritic cells (cDC1) are critical for antitumor immunity, and their abundance within tumors is associated with immune-mediated rejection and the success of immunotherapy. Here, we show that cDC1 accumulation in mouse tumors often depends on natural killer (NK) cells that produce the cDC1 chemoattractants CCL5 and XCL1. Similarly, in human cancers, intratumoral CCL5, XCL1, and XCL2 transcripts closely correlate with gene signatures of both NK cells and cDC1 and are associated with increased overall patient survival. Notably, tumor production of prostaglandin E2 (PGE2) leads to evasion of the NK cell-cDC1 axis in part by impairing NK cell viability and chemokine production, as well as by causing downregulation of chemokine receptor expression in cDC1. Our findings reveal a cellular and molecular checkpoint for intratumoral cDC1 recruitment that is targeted by tumor-derived PGE2 for immune evasion and that could be exploited for cancer therapy.
van der Veen AG, Maillard PV, Schmidt JM, et al., 2018, The RIG-I-like receptor LGP2 inhibits Dicer-dependent processing of long double-stranded RNA and blocks RNA interference in mammalian cells, EMBO JOURNAL, Vol: 37, ISSN: 0261-4189
Helft J, Anjos-Afonso F, van der Veen AG, et al., 2017, Dendritic Cell Lineage Potential in Human Early Hematopoietic Progenitors, CELL REPORTS, Vol: 20, Pages: 529-537, ISSN: 2211-1247
Reis e Sousa C, 2017, Sensing infection and tissue damage, EMBO Molecular Medicine, Vol: 9, Pages: 285-288, ISSN: 1757-4676
Innate and adaptive immunity work concertedly in vertebrates to restore homoeostasis following pathogen invasion or other insults. Like all homoeostatic circuits, immunity relies on an integrated system of sensors, transducers and effectors that can be analysed in cellular or molecular terms. At the cellular level, T and B lymphocytes act as an effector arm of immunity that is mobilised in response to signals transduced by innate immune cells that detect a given insult. These innate cells are spread around the body and include dendritic cells (DCs), the chief immune sensors of pathogen invasion and tumour growth. At the molecular level, DCs possess receptors that directly sense pathogen presence and tissue damage and that signal via transduction pathways to control antigen presentation or regulate a plethora of genes encoding effector proteins that regulate immunity. Notably, molecular circuits for pathogen detection are not confined to DCs or even to immune cells. All cells express sensors and transducers that monitor invasion by viruses and bacteria and elicit suitable effector barriers to pathogen propagation. Here, I discuss work from my laboratory that has contributed to our understanding of these issues over the years.
Srinivasan N, Gordon O, Ahrens S, et al., 2016, Actin is an evolutionarily-conserved damage-associated molecular pattern that signals tissue injury in Drosophila melanogaster, eLife, Vol: 5, ISSN: 2050-084X
Damage-associated molecular patterns (DAMPs) are molecules released by dead cells that trigger sterile inflammation and, in vertebrates, adaptive immunity. Actin is a DAMP detected in mammals by the receptor, DNGR-1, expressed by dendritic cells (DCs). DNGR-1 is phosphorylated by Src-family kinases and recruits the tyrosine kinase Syk to promote DC cross-presentation of dead cell-associated antigens. Here we report that actin is also a DAMP in invertebrates that lack DCs and adaptive immunity. Administration of actin to Drosophila melanogaster triggers a response characterised by selective induction of STAT target genes in the fat body through the cytokine Upd3 and its JAK/STAT-coupled receptor, Domeless. Notably, this response requires signalling via Shark, the Drosophila orthologue of Syk, and Src42A, a Drosophila Src-family kinase, and is dependent on Nox activity. Thus, extracellular actin detection via a Src-family kinase-dependent cascade is an ancient means of detecting cell injury that precedes the evolution of adaptive immunity.
Maillard PV, Van der Veen AG, Deddouche-Grass S, et al., 2016, Inactivation of the type I interferon pathway reveals long double-stranded RNA-mediated RNA interference in mammalian cells, EMBO Journal, Vol: 35, Pages: 2505-2518, ISSN: 0261-4189
RNA interference (RNAi) elicited by long double‐stranded (ds) or base‐paired viral RNA constitutes the major mechanism of antiviral defence in plants and invertebrates. In contrast, it is controversial whether it acts in chordates. Rather, in vertebrates, viral RNAs induce a distinct defence system known as the interferon (IFN) response. Here, we tested the possibility that the IFN response masks or inhibits antiviral RNAi in mammalian cells. Consistent with that notion, we find that sequence‐specific gene silencing can be triggered by long dsRNAs in differentiated mouse cells rendered deficient in components of the IFN pathway. This unveiled response is dependent on the canonical RNAi machinery and is lost upon treatment of IFN‐responsive cells with type I IFN. Notably, transfection with long dsRNA specifically vaccinates IFN‐deficient cells against infection with viruses bearing a homologous sequence. Thus, our data reveal that RNAi constitutes an ancient antiviral strategy conserved from plants to mammals that precedes but has not been superseded by vertebrate evolution of the IFN system.
Hanc P, Schulz O, Fischbach H, et al., 2016, A pH- and ionic strength-dependent conformational change in the neck region regulates DNGR-1 function in dendritic cells, EMBO Journal, Vol: 35, Pages: 2484-2497, ISSN: 0261-4189
DNGR‐1 is receptor expressed by certain dendritic cell (DC) subsets and by DC precursors in mouse. It possesses a C‐type lectin‐like domain (CTLD) followed by a poorly characterized neck region coupled to a transmembrane region and short intracellular tail. The CTLD of DNGR‐1 binds F‐actin exposed by dead cell corpses and causes the receptor to signal and potentiate cross‐presentation of dead cell‐associated antigens by DCs. Here, we describe a conformational change that occurs in the neck region of DNGR‐1 in a pH‐ and ionic strength‐dependent manner and that controls cross‐presentation of dead cell‐associated antigens. We identify residues in the neck region that, when mutated, lock DNGR‐1 in one of the two conformational states to potentiate cross‐presentation. In contrast, we show that chimeric proteins in which the neck region of DNGR‐1 is replaced by that of unrelated C‐type lectin receptors fail to promote cross‐presentation. Our results suggest that the neck region of DNGR‐1 is an integral receptor component that senses receptor progression through the endocytic pathway and has evolved to maximize extraction of antigens from cell corpses, coupling DNGR‐1 function to its cellular localization.
Zelenay S, Reis E Sousa C, 2016, Reducing prostaglandin E2 production to raise cancer immunogenicity, Oncoimmunology, Vol: 5, ISSN: 2162-4011
Cyclooxygenases (COX), commonly upregulated in numerous cancers, generate prostaglandin E2 (PGE2), which has been implicated in key aspects of malignant growth including proliferation, invasion and angiogenesis. Recently, we showed that production of PGE2 by cancer cells dominantly enables progressive tumor growth via immune escape and that cyclooxygenase inhibitors synergize with immunotherapy to enhance tumor eradication.
Acton SE, Reis e Sousa C, 2016, Dendritic cells in remodeling of lymph nodes during immune responses., Immunological Reviews, Vol: 271, Pages: 221-229, ISSN: 1600-065X
A critical hallmark of adaptive immune responses is the rapid and extensive expansion of lymph nodes. During this process, the complex internal structure of the organs is maintained revealing the existence of mechanisms able to balance lymph node integrity with structural flexibility. This article reviews the extensive architectural remodeling that occurs within lymph nodes during adaptive immune responses and how it is regulated by dendritic cells (DCs). In particular we focus on previously unappreciated functions of DCs in coordinating remodeling of lymph node vasculature, expansion of the fibroblastic reticular network and maintenance of lymphoid stromal phenotypes. Our increased understanding of these processes indicates that DCs need to be viewed not only as key antigen-presenting cells for lymphocytes but also as broad-acting immune sentinels that convey signals to lymphoid organ stroma and thereby facilitate immune response initiation at multiple levels.
Helft J, Böttcher JP, Chakravarty P, et al., 2016, Alive but Confused: Heterogeneity of CD11c(+) MHC Class II(+) Cells in GM-CSF Mouse Bone Marrow Cultures., Immunity, Vol: 44, Pages: 3-4, ISSN: 1074-7613
Goubau D, van der Veen AG, Chakravarty P, et al., 2015, Mouse superkiller-2-like helicase DDX60 is dispensable for type I IFN induction and immunity to multiple viruses, EUROPEAN JOURNAL OF IMMUNOLOGY, Vol: 45, Pages: 3386-3403, ISSN: 0014-2980
Boettcher JP, Zelenay S, Rogers NC, et al., 2015, Oncogenic Transformation of Dendritic Cells and Their Precursors Leads to Rapid Cancer Development in Mice, JOURNAL OF IMMUNOLOGY, Vol: 195, Pages: 5066-5076, ISSN: 0022-1767
van der Veen AG, Maillard PV, Reis e Sousa C, 2015, Drosha cuts the tethers of myelopoiesis, NATURE IMMUNOLOGY, Vol: 16, Pages: 1110-1112, ISSN: 1529-2908
Yatim N, Jusforgues-Saklani H, Orozco S, et al., 2015, RIPK1 and NF-kappa B signaling in dying cells determines cross-priming of CD8(+) T cells, SCIENCE, Vol: 350, Pages: 328-+, ISSN: 0036-8075
Zelenay S, van der Veen AG, Böttcher JP, et al., 2015, Cyclooxygenase-dependent tumor growth through evasion of immunity, Cell, Vol: 162, Pages: 1257-1270, ISSN: 0092-8674
The mechanisms by which melanoma and other cancer cells evade anti-tumor immunity remain incompletely understood. Here, we show that the growth of tumors formed by mutant Braf(V600E) mouse melanoma cells in an immunocompetent host requires their production of prostaglandin E2, which suppresses immunity and fuels tumor-promoting inflammation. Genetic ablation of cyclooxygenases (COX) or prostaglandin E synthases in Braf(V600E) mouse melanoma cells, as well as in Nras(G12D) melanoma or in breast or colorectal cancer cells, renders them susceptible to immune control and provokes a shift in the tumor inflammatory profile toward classic anti-cancer immune pathways. This mouse COX-dependent inflammatory signature is remarkably conserved in human cutaneous melanoma biopsies, arguing for COX activity as a driver of immune suppression across species. Pre-clinical data demonstrate that inhibition of COX synergizes with anti-PD-1 blockade in inducing eradication of tumors, implying that COX inhibitors could be useful adjuvants for immune-based therapies in cancer patients.
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