-
[show abstract]
[hide abstract]
ABSTRACT: The success of a vaccine consists in the induction of an innate immune response and subsequent activation of the adaptive immune system. Because antigens are usually not immunogenic, the addition of adjuvants that activate innate immunity is required. The mycobacterial cord factor trehalose-6,6'-dimycolate (TDM) and its synthetic adjuvant analogue trehalose-6,6'-dibehenate (TDB) rely on the C-type lectin Mincle and the signaling molecules Syk and Card9 to trigger innate immunity. In this study, we show that stimulation of bone marrow-derived dendritic cells (BMDCs) with TDB induces Nlrp3 inflammasome-dependent IL-1β secretion. While Card9 is required for NF-κB activation by TDB, it is dispensable for TDB-induced activation of the Nlrp3 inflammasome. Additionally, efflux of intracellular potassium, lysosomal rupture, and oxygen radical (ROS) production are crucial for caspase-1 processing and IL-1β secretion by TDB. In an in vivo inflammation model, we demonstrate that the recruitment of neutrophils by TDB is significantly reduced in the Nlrp3-deficient mice compared to the wild-type mice, while the production of chemokines in vitro is not influenced by the absence of Nlrp3. These results identify the Nlrp3 inflammasome as an essential mediator for the induction of an innate immune response triggered by TDB.
Immunobiology 08/2012; · 3.20 Impact Factor
-
Angela Dann, Hendrik Poeck,
Andrew L Croxford,
Stefanie Gaupp,
Katrin Kierdorf,
Markus Knust,
Dietmar Pfeifer,
Cornelius Maihoefer,
Stefan Endres,
Ulrich Kalinke,
Sven G Meuth,
Heinz Wiendl,
Klaus-Peter Knobeloch,
Shizuo Akira,
Ari Waisman,
Gunther Hartmann,
Marco Prinz
[show abstract]
[hide abstract]
ABSTRACT: The action of cytosolic RIG-I-like helicases (RLHs) in the CNS during autoimmunity is largely unknown. Using a mouse model of multiple sclerosis, we found that mice lacking the RLH adaptor IPS-1 developed exacerbated disease that was accompanied by markedly higher inflammation, increased axonal damage and elevated demyelination with increased encephalitogenic immune responses. Furthermore, activation of RLH ligands such as 5'-triphosphate RNA oligonucleotides decreased CNS inflammation and improved clinical signs of disease. RLH stimulation repressed the maintenance and expansion of committed T(H)1 and T(H)17 cells, whereas T-cell differentiation was not altered. Notably, T(H)1 and T(H)17 suppression required type I interferon receptor engagement on dendritic cells, but not on macrophages or microglia. These results identify RLHs as negative regulators of T(H)1 and T(H)17 responses in the CNS, demonstrate a protective role of the RLH pathway for brain inflammation, and establish oligonucleotide ligands of RLHs as potential therapeutics for the treatment of multiple sclerosis.
Nature Neuroscience 12/2011; 15(1):98-106. · 15.53 Impact Factor
-
Michael Wenzel,
Michael Wunderlich,
Robert Besch, Hendrik Poeck,
Simone Willms,
Astrid Schwantes,
Melanie Kremer,
Gerd Sutter,
Stefan Endres,
Andreas Schmidt,
Simon Rothenfusser
[show abstract]
[hide abstract]
ABSTRACT: A key host response to limit microbial spread is the induction of cell death when foreign nucleic acids are sensed within infected cells. In mouse macrophages, transfected DNA or infection with modified vaccinia virus Ankara (MVA) can trigger cell death via the absent in melanoma 2 (AIM2) inflammasome. In this article, we show that nonmyeloid human cell types lacking a functional AIM2 inflammasome still die in response to cytosolic delivery of different DNAs or infection with MVA. This cell death induced by foreign DNA is independent of caspase-8 and carries features of mitochondrial apoptosis: dependence on BAX, APAF-1, and caspase-9. Although it does not require the IFN pathway known to be triggered by infection with MVA or transfected DNA via polymerase III and retinoid acid-induced gene I-like helicases, it shows a strong dependence on components of the DNA damage signaling pathway: cytosolic delivery of DNA or infection with MVA leads to phosphorylation of p53 (serines 15 and 46) and autophosphorylation of ataxia telangiectasia mutated (ATM); depleting p53 or ATM with small interfering RNA or inhibiting the ATM/ATM-related kinase family by caffeine strongly reduces apoptosis. Taken together, our findings suggest that a pathway activating DNA damage signaling plays an important independent role in detecting intracellular foreign DNA, thereby complementing the induction of IFN and activation of the AIM2 inflammasome.
The Journal of Immunology 12/2011; 188(1):394-403. · 5.79 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Approved therapies for chronic hepatitis B include systemic administration of interferon (IFN)-alfa and inhibitors of hepatitis B virus (HBV) reverse-transcription. Systemic application of IFN-alfa is limited by side effects. Reverse-transcriptase inhibitors effectively control HBV replication, but rarely eliminate the virus and can select drug-resistant variants. We aimed to develop an alternative therapeutic approach that combines gene silencing with induction of IFN in the liver.
To stimulate an immune response while inhibiting HBV activity, we designed 3 small interfering (si)RNAs that target highly conserved sequences and multiple HBV transcripts of all genotypes. A 5'-triphosphate (3p) was added to the siRNAs, turning them into a ligand for the cytosolic helicase retinoic acid-inducible protein I, which becomes activated and induces expression of type-I IFNs. Antiviral activity was investigated in cell lines that replicate HBV, in HBV-infected primary human hepatocytes, and in HBV transgenic mice.
3p-double-stranded RNA (3p-RNA) activated retinoic acid-inducible protein I, induced a strong type I IFN response (expression of IFN-β) in liver cells and showed transient but strong antiviral activity. Bifunctional, HBV-specific, 3p-siRNAs controlled replication of HBV more efficiently and for longer periods of time than 3p-RNAs without silencing capacity or siRNAs that targeted identical sequences but did not contain 3p.
HBV-specific 3p-siRNAs are bifunctional antiviral molecules that induce production of type I IFNs in the liver and target HBV RNAs to inhibit viral replication.
Gastroenterology 05/2011; 141(2):696-706, 706.e1-3. · 11.68 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Early detection of viruses by the innate immune system is critical for host defense. Antiviral immunity is initiated by germline encoded pattern recognition receptors (PRRs) that recognize viral pathogen-associated molecular patterns (PAMPs) such as nucleic acids. Intracellular PRRs then drive the production of interferons and cytokines to orchestrate immune responses. One key host factor that is critical for antiviral immunity and for systemic inflammatory reactions including fever is interleukin-1beta (IL-1β). Here we discuss current insights into the molecular mechanisms how the cytosolic RNA helicase RIG-I triggers NF-κB signaling and inflammasome activation specifically for RNA virus-induced IL-1β production.
European journal of cell biology 04/2011; 91(1):59-64. · 3.31 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Host protection against fungi depends on intact innate and adaptive immune responses. Consistently, fungal infections can cause systemic life-threatening diseases in immunocomprimised individuals, suffering e.g. from cancer or AIDS. Recent work has uncovered essential roles for the spleen tyrosine kinase (SYK) and the cytosolic NLRP3 inflammasome for Interleukin-1beta (IL-1beta) production in innate antifungal immunity. Upon fungal infection, SYK is activated by several C-type lectin pattern recognition receptors on myeloid cells. Subsequently, SYK signals for the production of reactive oxygen species and for gene transcription to induce pro-inflammatory factors, including pro-IL-1beta to initiate antifungal responses. Mature IL-1beta production additionally requires cleavage of the pro-IL-1beta precursor protein by the inflammatory caspase-1 which is controlled within the NLRP3 inflammasome. Here, we discuss how SYK signaling cooperates with the NLRP3 inflammasome for IL-1beta production in antifungal immunity.
Journal of Molecular Medicine 08/2010; 88(8):745-52. · 4.67 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: INTRODUCTION: Infections with fungi can cause systemic life-threatening diseases in immunocompromised individuals like cancer or AIDS patients. Recent work has uncovered essential roles for C-type lectin pattern recognition receptors, spleen tyrosine kinase (SYK) and the cytosolic NLRP3 inflammasome in innate antifungal immunity. Upon fungal infection, SYK is activated by several ITAM-containing or ITAM-coupled C-type lectin receptors on myeloid cells leading to the production of pro-inflammatory cytokines including IL-1beta to initiate antifungal responses. Mature IL-1beta production requires in addition to the synthesis of pro-IL-1beta a cleavage of the precursor protein by the inflammatory Caspase-1 which is controlled within the NLRP3 inflammasome. SCOPE: Here, we discuss how ITAM receptor signaling and NLRP3 cooperate for the induction of antifungal immunity.
Journal of Clinical Immunology 07/2010; 30(4):496-501. · 3.08 Impact Factor
-
David Anz,
Viktor H Koelzer,
Stefan Moder,
Raffael Thaler,
Tobias Schwerd,
Katharina Lahl,
Tim Sparwasser,
Robert Besch, Hendrik Poeck,
Veit Hornung,
Gunther Hartmann,
Simon Rothenfusser,
Carole Bourquin,
Stefan Endres
[show abstract]
[hide abstract]
ABSTRACT: The role of immune suppression by regulatory T (Treg) cells in the maintenance of immune homeostasis is well established. However, little is known about how Treg cell function is inhibited on viral infection to allow the development of a protective immune response. As viral RNA is a crucial mediator for activation of antiviral immunity, we examined the effects of immunostimulatory RNA and infection with RNA viruses on Treg cell function. We show that synthetic RNA oligonucleotides potently inhibit Treg cell-induced suppression in a sequence-dependent manner. This effect is entirely dependent on TLR7 activation of APCs and subsequent IL-6 production. In addition, stimulation with the RNA viruses encephalomyocarditis virus and Sendai virus that specifically activate the RNA-sensing helicases melanoma differentiation-associated gene 5 (MDA-5) and retinoic acid-inducible gene I (RIG-I) also blocks Treg cell function. Interestingly, this effect is seen even in the absence of APCs. Consistent with this, both Treg and T effector cells express RIG-I and MDA-5. Using MDA-5-deficient mice, we demonstrate that the loss of Treg cell function on infection with encephalomyocarditis virus is strictly dependent on MDA-5 expression by Treg cells. Thus, we show in this study for the first time that activation of a RIG-I-like helicase on Treg cells blocks their suppressive function.
The Journal of Immunology 12/2009; 184(2):939-46. · 5.79 Impact Factor
-
Carole Bourquin,
Laura Schmidt,
Anna-Lisa Lanz,
Bettina Storch,
Cornelia Wurzenberger,
David Anz,
Nadja Sandholzer,
Ralph Mocikat,
Michael Berger, Hendrik Poeck,
Gunther Hartmann,
Veit Hornung,
Stefan Endres
[show abstract]
[hide abstract]
ABSTRACT: RNA oligonucleotides containing immune-activating sequences promote the development of cytotoxic T cell and B cell responses to Ag. In this study, we show for the first time that immunostimulatory RNA oligonucleotides induce a NK cell response that prevents growth of NK-sensitive tumors. Treatment of mice with immunostimulatory RNA oligonucleotides activates NK cells in a sequence-dependent manner, leading to enhanced IFN-gamma production and increased cytotoxicity. Use of gene-deficient mice showed that NK activation is entirely TLR7-dependent. We further demonstrate that NK activation is indirectly induced through IL-12 and type I IFN production by dendritic cells. Reconstitution of TLR7-deficient mice with wild-type dendritic cells restores NK activation upon treatment with immunostimulatory RNA oligonucleotides. Thus, by activating both NK cells and CTLs, RNA oligonucleotides stimulate two major cellular effectors of antitumor immunity. This dual activation may enhance the efficacy of immunotherapeutic strategies against cancer by preventing the development of tumor immune escape variants.
The Journal of Immunology 11/2009; 183(10):6078-86. · 5.79 Impact Factor
-
Hendrik Poeck,
Michael Bscheider,
Olaf Gross,
Katrin Finger,
Susanne Roth,
Manuele Rebsamen,
Nicole Hannesschläger,
Martin Schlee,
Simon Rothenfusser,
Winfried Barchet,
Hiroki Kato,
Shizuo Akira,
Satoshi Inoue,
Stefan Endres,
Christian Peschel,
Gunther Hartmann,
Veit Hornung,
Jürgen Ruland
[show abstract]
[hide abstract]
ABSTRACT: Interleukin 1 beta (IL-1 beta) is a potent proinflammatory factor during viral infection. Its production is tightly controlled by transcription of Il1b dependent on the transcription factor NF-kappaB and subsequent processing of pro-IL-1 beta by an inflammasome. However, the sensors and mechanisms that facilitate RNA virus-induced production of IL-1 beta are not well defined. Here we report a dual role for the RNA helicase RIG-I in RNA virus-induced proinflammatory responses. Whereas RIG-I-mediated activation of NF-kappaB required the signaling adaptor MAVS and a complex of the adaptors CARD9 and Bcl-10, RIG-I also bound to the adaptor ASC to trigger caspase-1-dependent inflammasome activation by a mechanism independent of MAVS, CARD9 and the Nod-like receptor protein NLRP3. Our results identify the CARD9-Bcl-10 module as an essential component of the RIG-I-dependent proinflammatory response and establish RIG-I as a sensor able to activate the inflammasome in response to certain RNA viruses.
Nature Immunology 11/2009; 11(1):63-9. · 26.01 Impact Factor
-
Robert Besch, Hendrik Poeck,
Tobias Hohenauer,
Daniela Senft,
Georg Häcker,
Carola Berking,
Veit Hornung,
Stefan Endres,
Thomas Ruzicka,
Simon Rothenfusser,
Gunther Hartmann
[show abstract]
[hide abstract]
ABSTRACT: The retinoic acid-inducible gene I (RIG-I) and melanoma differentiation-associated antigen 5 (MDA-5) helicases sense viral RNA in infected cells and initiate antiviral responses such as the production of type I IFNs. Here we have shown that RIG-I and MDA-5 also initiate a proapoptotic signaling pathway that is independent of type I IFNs. In human melanoma cells, this signaling pathway required the mitochondrial adapter Cardif (also known as IPS-1) and induced the proapoptotic BH3-only proteins Puma and Noxa. RIG-I- and MDA-5-initiated apoptosis required Noxa but was independent of the tumor suppressor p53. Triggering this pathway led to efficient activation of mitochondrial apoptosis, requiring caspase-9 and Apaf-1. Surprisingly, this proapoptotic signaling pathway was also active in nonmalignant cells, but these cells were much less sensitive to apoptosis than melanoma cells. Endogenous Bcl-xL rescued nonmalignant, but not melanoma, cells from RIG-I- and MDA-5-mediated apoptosis. In addition, we confirmed the results of the in vitro studies, demonstrating that RIG-I and MDA-5 ligands both reduced human tumor lung metastasis in immunodeficient NOD/SCID mice. These results identify an IFN-independent antiviral signaling pathway initiated by RIG-I and MDA-5 that activates proapoptotic signaling and, unless blocked by Bcl-xL, results in apoptosis. Due to their immunostimulatory and proapoptotic activity, RIG-I and MDA-5 ligands have therapeutic potential due to their ability to overcome the characteristic resistance of melanoma cells to apoptosis.
The Journal of clinical investigation 09/2009; 119(8):2399-411. · 15.39 Impact Factor
-
Martin Schlee,
Andreas Roth,
Veit Hornung,
Cristina Amparo Hagmann,
Vera Wimmenauer,
Winfried Barchet,
Christoph Coch,
Markus Janke,
Aleksandra Mihailovic,
Greg Wardle, [......],
Hiroki Kato,
Taro Kawai, Hendrik Poeck,
Katherine A Fitzgerald,
Osamu Takeuchi,
Shizuo Akira,
Thomas Tuschl,
Eicke Latz,
Janos Ludwig,
Gunther Hartmann
[show abstract]
[hide abstract]
ABSTRACT: Antiviral immunity is triggered by immunorecognition of viral nucleic acids. The cytosolic helicase RIG-I is a key sensor of viral infections and is activated by RNA containing a triphosphate at the 5' end. The exact structure of RNA activating RIG-I remains controversial. Here, we established a chemical approach for 5' triphosphate oligoribonucleotide synthesis and found that synthetic single-stranded 5' triphosphate oligoribonucleotides were unable to bind and activate RIG-I. Conversely, the addition of the synthetic complementary strand resulted in optimal binding and activation of RIG-I. Short double-strand conformation with base pairing of the nucleoside carrying the 5' triphosphate was required. RIG-I activation was impaired by a 3' overhang at the 5' triphosphate end. These results define the structure of RNA for full RIG-I activation and explain how RIG-I detects negative-strand RNA viruses that lack long double-stranded RNA but do contain blunt short double-stranded 5' triphosphate RNA in the panhandle region of their single-stranded genome.
Immunity 08/2009; 31(1):25-34. · 21.64 Impact Factor
-
Andrea Ablasser, Hendrik Poeck,
David Anz,
Michael Berger,
Martin Schlee,
Sarah Kim,
Carole Bourquin,
Nadege Goutagny,
Zhaozhao Jiang,
Katherine A Fitzgerald,
Simon Rothenfusser,
Stefan Endres,
Gunther Hartmann,
Veit Hornung
[show abstract]
[hide abstract]
ABSTRACT: Detection of non-self RNA by TLRs within endosomes and by retinoic acid-inducible gene I (RIG-I)-like helicases in the cytosol is central to mammalian antiviral immunity. In this study, we used pathway-specific agonists and targeted delivery to address RNA immunorecognition in primary human immune cells. Within PBMC, plasmacytoid dendritic cells (pDC) and monocytes were found to be responsible for IFN-alpha production upon immunorecognition of RNA. The mechanisms of RNA recognition in pDC and monocytes were distinct. In pDC, recognition of ssRNA and dsRNA oligonucleotides was TLR7-dependent, whereas a 5' triphosphate moiety (RIG-I ligand activity) had no major contribution to IFN-alpha production. In monocytes, the response to RNA oligonucleotides was mediated by either TLR8 or RIG-I. TLR8 was responsible for IL-12 induction upon endosomal delivery of ssRNA oligonucleotides and RIG-I was responsible for IFN-alpha production upon delivery of 5' triphosphate RNA into the cytosol. In conclusion, the dissection of these pathways by selecting the appropriate structure and delivery of RNA reveals pDC as major producer of IFN-alpha upon TLR-mediated stimulation and monocytes as major producer of IFN-alpha upon RIG-I-mediated stimulation. Furthermore, our results uncover the potential of monocytes to function as major producers of IL-12p70, a key Th1 cytokine classically ascribed to myeloid dendritic cells that cannot be induced by CpG oligonucleotides in the human system.
The Journal of Immunology 07/2009; 182(11):6824-33. · 5.79 Impact Factor
-
Olaf Gross, Hendrik Poeck,
Michael Bscheider,
Catherine Dostert,
Nicole Hannesschläger,
Stefan Endres,
Gunther Hartmann,
Aubry Tardivel,
Edina Schweighoffer,
Victor Tybulewicz,
Attila Mocsai,
Jürg Tschopp,
Jürgen Ruland
[show abstract]
[hide abstract]
ABSTRACT: Fungal infections represent a serious threat, particularly in immunocompromised patients. Interleukin-1beta (IL-1beta) is a key pro-inflammatory factor in innate antifungal immunity. The mechanism by which the mammalian immune system regulates IL-1beta production after fungal recognition is unclear. Two signals are generally required for IL-1beta production: an NF-kappaB-dependent signal that induces the synthesis of pro-IL-1beta (p35), and a second signal that triggers proteolytic pro-IL-1beta processing to produce bioactive IL-1beta (p17) via Caspase-1-containing multiprotein complexes called inflammasomes. Here we demonstrate that the tyrosine kinase Syk, operating downstream of several immunoreceptor tyrosine-based activation motif (ITAM)-coupled fungal pattern recognition receptors, controls both pro-IL-1beta synthesis and inflammasome activation after cell stimulation with Candida albicans. Whereas Syk signalling for pro-IL-1beta synthesis selectively uses the Card9 pathway, inflammasome activation by the fungus involves reactive oxygen species production and potassium efflux. Genetic deletion or pharmalogical inhibition of Syk selectively abrogated inflammasome activation by C. albicans but not by inflammasome activators such as Salmonella typhimurium or the bacterial toxin nigericin. Nlrp3 (also known as NALP3) was identified as the critical NOD-like receptor family member that transduces the fungal recognition signal to the inflammasome adaptor Asc (Pycard) for Caspase-1 (Casp1) activation and pro-IL-1beta processing. Consistent with an essential role for Nlrp3 inflammasomes in antifungal immunity, we show that Nlrp3-deficient mice are hypersusceptible to Candida albicans infection. Thus, our results demonstrate the molecular basis for IL-1beta production after fungal infection and identify a crucial function for the Nlrp3 inflammasome in mammalian host defence in vivo.
Nature 05/2009; 459(7245):433-6. · 36.28 Impact Factor
-
Hendrik Poeck,
Robert Besch,
Cornelius Maihoefer,
Marcel Renn,
Damia Tormo,
Svetlana Shulga Morskaya,
Susanne Kirschnek,
Evelyn Gaffal,
Jennifer Landsberg,
Johannes Hellmuth, [......],
Georg Häcker,
Michael Neuenhahn,
Dirk Busch,
Jürgen Ruland,
Simon Rothenfusser,
Marco Prinz,
Veit Hornung,
Stefan Endres,
Thomas Tüting,
Gunther Hartmann
[show abstract]
[hide abstract]
ABSTRACT: Genetic and epigenetic plasticity allows tumors to evade single-targeted treatments. Here we direct Bcl2-specific short interfering RNA (siRNA) with 5'-triphosphate ends (3p-siRNA) against melanoma. Recognition of 5'-triphosphate by the cytosolic antiviral helicase retinoic acid-induced protein I (Rig-I, encoded by Ddx58) activated innate immune cells such as dendritic cells and directly induced expression of interferons (IFNs) and apoptosis in tumor cells. These Rig-I-mediated activities synergized with siRNA-mediated Bcl2 silencing to provoke massive apoptosis of tumor cells in lung metastases in vivo. The therapeutic activity required natural killer cells and IFN, as well as silencing of Bcl2, as evidenced by rescue with a mutated Bcl2 target, by site-specific cleavage of Bcl2 messenger RNA in lung metastases and downregulation of Bcl-2 protein in tumor cells in vivo. Together, 3p-siRNA represents a single molecule-based approach in which Rig-I activation on both the immune- and tumor cell level corrects immune ignorance and in which gene silencing corrects key molecular events that govern tumor cell survival.
Nature medicine 12/2008; 14(11):1256-63. · 27.14 Impact Factor
-
Marie-Cécile Michallet,
Etienne Meylan,
Maria A Ermolaeva,
Jessica Vazquez,
Manuele Rebsamen,
Joseph Curran, Hendrik Poeck,
Michael Bscheider,
Gunther Hartmann,
Martin König,
Ulrich Kalinke,
Manolis Pasparakis,
Jürg Tschopp
[show abstract]
[hide abstract]
ABSTRACT: Upon detection of viral RNA, the helicases RIG-I and/or MDA5 trigger, via their adaptor Cardif (also known as IPS-1, MAVS, or VISA), the activation of the transcription factors NF-kappaB and IRF3, which collaborate to induce an antiviral type I interferon (IFN) response. FADD and RIP1, known as mediators of death-receptor signaling, are implicated in this antiviral pathway; however, the link between death-receptor and antiviral signaling is not known. Here we showed that TRADD, a crucial adaptor of tumor necrosis factor receptor (TNFRI), was important in RIG-like helicase (RLH)-mediated signal transduction. TRADD is recruited to Cardif and orchestrated complex formation with the E3 ubiquitin ligase TRAF3 and TANK and with FADD and RIP1, leading to the activation of IRF3 and NF-kappaB. Loss of TRADD prevented Cardif-dependent activation of IFN-beta, reduced the production of IFN-beta in response to RNA viruses, and enhanced vesicular stomatitis virus replication. Thus, TRADD is not only an essential component of proinflammatory TNFRI signaling, but is also required for RLH-Cardif-dependent antiviral immune responses.
Immunity 06/2008; 28(5):651-61. · 21.64 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The role of plasmacytoid dendritic cells (PDC), the major producers of alpha interferon upon viral infection, in the nasal mucosa is largely unknown. Here we examined the presence of PDC together with myeloid dendritic cells (MDC) in the nasal epithelia of healthy individuals, of asymptomatic patients with chronic nasal allergy, of patients undergoing steroid therapy, and of patients with infectious rhinitis or rhinosinusitis. Considerable numbers of PDC and MDC could be detected in the nasal epithelium. Furthermore, we demonstrate the expression of SDF-1, the major chemoattractant for PDC, in the nasal epithelium. PDC levels were significantly lower for patients with allergies than for healthy individuals. Interestingly, PDC and MDC were almost absent from patients who received treatment with glucocorticoids, while very high numbers of PDC were found for patients with recent upper respiratory tract infections. Our results demonstrate for the first time a quantitative analysis of PDC and MDC in the healthy nasal epithelium and in nasal epithelia from patients with different pathological conditions. With the identification of PDC, the major target cell for CpG DNA or immunostimulatory RNA, in the nasal epithelium, this study forms the basis for a local nasal application of such oligonucleotides for the treatment of viral infection and allergy.
Clinical and Vaccine Immunology 12/2006; 13(11):1278-86. · 2.55 Impact Factor
-
Veit Hornung,
Jana Ellegast,
Sarah Kim,
Krzysztof Brzózka,
Andreas Jung,
Hiroki Kato, Hendrik Poeck,
Shizuo Akira,
Karl-Klaus Conzelmann,
Martin Schlee,
Stefan Endres,
Gunther Hartmann
[show abstract]
[hide abstract]
ABSTRACT: The structural basis for the distinction of viral RNA from abundant self RNA in the cytoplasm of virally infected cells is largely unknown. We demonstrated that the 5'-triphosphate end of RNA generated by viral polymerases is responsible for retinoic acid-inducible protein I (RIG-I)-mediated detection of RNA molecules. Detection of 5'-triphosphate RNA is abrogated by capping of the 5'-triphosphate end or by nucleoside modification of RNA, both occurring during posttranscriptional RNA processing in eukaryotes. Genomic RNA prepared from a negative-strand RNA virus and RNA prepared from virus-infected cells (but not from noninfected cells) triggered a potent interferon-alpha response in a phosphatase-sensitive manner. 5'-triphosphate RNA directly binds to RIG-I. Thus, uncapped 5'-triphosphate RNA (now termed 3pRNA) present in viruses known to be recognized by RIG-I, but absent in viruses known to be detected by MDA-5 such as the picornaviruses, serves as the molecular signature for the detection of viral infection by RIG-I.
Science 12/2006; 314(5801):994-7. · 31.20 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The aim of this paper was to investigate if the immunostimulatory effects of CpG-oligonucleotides (CpG-ODN) can be enhanced by the use of biodegradable protamine nanoparticles (proticles). We analyzed size, surface charge, and morphology of protamine nanoparticles containing CpG-ODN with photon correlation spectroscopy and transmission electron microscopy. Immunostimulatory effects of these nanoparticles on B cells, plasmacytoid dendritic cells (PDC), peripheral blood mononuclear cells, and whole blood were studied. Cytokine production, activation of the cells in terms of upregulation of surface molecules and uptake of nanoparticles were examined. We found that the use of protamine nanoparticles significantly increased (20-fold) CpG-ODN mediated interferon (IFN)-alpha production of PDC. ODN uptake in PDC was only marginally enhanced. CpG-ODN mediated IP-10 production in whole blood was strongly enhanced by the use of nanoparticles. Apart from a slight increase in CpG-ODN-induced interleukin (IL)-6 production in B cells, other parameters like the CpG-mediated activation of B cells and PDC as well as tumor necrosis factor (TNF)-alpha production of PDC remained largely unchanged. The use of control ODN indicated that the protamine nanoparticles themselves have no immunostimulatory properties. These results strongly support the use of particulate delivery systems like biodegradable protamine nanoparticles for the development of CpG-ODN-based therapeutics.
Oligonucleotides 02/2006; 16(4):313-22. · 2.80 Impact Factor
-
Anja Marschner,
Simon Rothenfusser,
Veit Hornung,
Domenik Prell,
Anne Krug,
Miren Kerkmann,
Daniela Wellisch, Hendrik Poeck,
Andreas Greinacher,
Thomas Giese,
Stefan Endres,
Gunther Hartmann
[show abstract]
[hide abstract]
ABSTRACT: Human Valpha24+ Vbeta11+ natural killer T cells (NKT cells) are "natural memory" T cells that detect glycolipid antigens such as alpha-galactosylceramide (alpha-GalCer) presented on CD1d. In the present study we found that highly purified Valpha24+ NKT cells lack TLR9 mRNA, and thus are not sensitive towards stimulation with CpG oligodeoxynucleotides (ODN). Within PBMC, however, CpG ODN synergistically activated NKT cells stimulated with their cognate antigen alpha-GalCer. Depletion of plasmacytoid dendritic cells (PDC) or myeloid dendritic cells (MDC) revealed that both DC subsets were necessary for the synergistic activation of NKT cells by alpha-GalCer and CpG ODN. While PDC were responsible for the stimulation of NKT cells with CpG ODN, MDC but not PDC presented alpha-GalCer via CD1d. Partial activation of NKT cells was mediated by PDC-derived IFN-alpha, whereas full activation of NKT cells as indicated by IFN-gamma production required cell-to-cell contact of PDC and NKT cells in addition to IFN-alpha; OX40 was involved in this interaction. We conclude that CpG-activated PDC enhance alpha-GalCer-specific NKT cell activation, and bias activated NKT cells towards a Th1 phenotype. Our results lead to a novel concept of PDC function: to regulate effector activity of antigen-stimulated T cells in a cell contact-dependent manner without the need of simultaneous presentation of the cognate T cell antigen.
European Journal of Immunology 09/2005; 35(8):2347-57. · 5.10 Impact Factor
