scholarly journals Autoimmune skin inflammation is dependent on plasmacytoid dendritic cell activation by nucleic acids via TLR7 and TLR9

2010 ◽  
Vol 207 (13) ◽  
pp. 2931-2942 ◽  
Author(s):  
Cristiana Guiducci ◽  
Claudio Tripodo ◽  
Mei Gong ◽  
Sabina Sangaletti ◽  
Mario P. Colombo ◽  
...  
Keyword(s):  
Lupus Erythematosus ◽  
Cell Activation ◽  
Skin Diseases ◽  
Plasmacytoid Dendritic Cell ◽  
Skin Inflammation ◽  
Tape Stripping ◽  
Type I ◽  
Type I Ifn ◽  
Dendritic Cell Activation ◽  
Cutaneous Lupus

Recognition of endogenous DNA and RNA by cells expressing TLR7 and TLR9 is an important contributor to the pathogenesis of systemic lupus erythematosus and has been suggested to contribute to cutaneous lupus and to a group of related inflammatory skin diseases termed interface dermatitis. We have developed a mouse model of TLR7- and TLR9-dependent skin inflammation using tape stripping. In normal mice, this resulted in a rapid but transient inflammatory cell infiltration accompanied by induction of type I IFN production by plasmacytoid dendritic cells (PDCs) and release of extracellular traps and proinflammatory cytokines by neutrophils. These responses were strongly reduced in MyD88-deficient mice and in mice treated with a bifunctional inhibitor of TLR7 and TLR9. In contrast, in lupus-prone (NZBxNZW)F1 mice, tape stripping induced the development of chronic lesions characterized by a persistent type I IFN gene signature and many clinical and histological features of cutaneous lupus. Depletion of PDCs before injury prevented the development of skin lesions, whereas treatment with a bifunctional TLR7/9 inhibitor before tape stripping or after the initial lesion was established led to a significant reduction of the disease. These data suggest that inhibitors of TLR7 and TLR9 signaling have potential therapeutic application for the treatment of interface dermatitis.

scholarly journals Selective control of type I IFN induction by the Rac activator DOCK2 during TLR-mediated plasmacytoid dendritic cell activation

2010 ◽  
Vol 207 (4) ◽  
pp. 721-730 ◽  
Author(s):  
Kazuhito Gotoh ◽  
Yoshihiko Tanaka ◽  
Akihiko Nishikimi ◽  
Risa Nakamura ◽  
Hisakata Yamada ◽  
...  
Keyword(s):  
Autoimmune Diseases ◽  
Signaling Pathway ◽  
Cell Activation ◽  
Nuclear Translocation ◽  
Plasmacytoid Dendritic Cell ◽  
Dominant Negative ◽  
Type I ◽  
Type I Ifn ◽  
Dendritic Cell Activation ◽  
Iκb Kinase

Plasmacytoid dendritic cells (pDCs) play a key role in antiviral immunity, but also contribute to the pathogenesis of certain autoimmune diseases, by producing large amounts of type I IFNs. Although activation of pDCs is triggered by engagement of nucleotide-sensing toll-like receptors (TLR) 7 and 9, type I IFN induction additionally requires IκB kinase (IKK) α–dependent activation of IFN regulatory factor (IRF) 7. However, the signaling pathway mediating IKK-α activation is poorly defined. We show that DOCK2, an atypical Rac activator, is essential for TLR7- and TLR9-mediated IFN-α induction in pDCs. We found that the exposure of pDCs to nucleic acid ligands induces Rac activation through a TLR-independent and DOCK2-dependent mechanism. Although this Rac activation was dispensable for induction of inflammatory cytokines, phosphorylation of IKK-α and nuclear translocation of IRF-7 were impaired in Dock2-deficient pDCs, resulting in selective loss of IFN-α induction. Similar results were obtained when a dominant-negative Rac mutant was expressed in wild-type pDCs. Thus, the DOCK2–Rac signaling pathway acts in parallel with TLR engagement to control IKK-α activation for type I IFN induction. Owing to its hematopoietic cell-specific expression, DOCK2 may serve as a therapeutic target for type I IFN–related autoimmune diseases.

scholarly journals Type I Interferon Inhibition and Dendritic Cell Activation during Gammaherpesvirus Respiratory Infection

2007 ◽  
Vol 81 (18) ◽  
pp. 9778-9789 ◽  
Author(s):  
Janet L. Weslow-Schmidt ◽  
Nancy A. Jewell ◽  
Sara E. Mertz ◽  
J. Pedro Simas ◽  
Joan E. Durbin ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Dendritic Cell ◽  
Cell Activation ◽  
Type I Interferon ◽  
Plasmacytoid Dendritic Cells ◽  
The Body ◽  
Type I ◽  
Type I Ifn ◽  
Dendritic Cell Activation ◽  
Murine Gammaherpesvirus

ABSTRACT The respiratory tract is a major mucosal site for microorganism entry into the body, and type I interferon (IFN) and dendritic cells constitute a first line of defense against viral infections. We have analyzed the interaction between a model DNA virus, plasmacytoid dendritic cells, and type I IFN during lung infection of mice. Our data show that murine gammaherpesvirus 68 (γHV68) inhibits type I IFN secretion by dendritic cells and that plasmacytoid dendritic cells are necessary for conventional dendritic cell maturation in response to γHV68. Following γHV68 intranasal inoculation, the local and systemic IFN-α/β response is below detectable levels, and plasmacytoid dendritic cells are activated and recruited into the lung with a tissue distribution that differs from that of conventional dendritic cells. Our results suggest that plasmacytoid dendritic cells and type I IFN have important but independent roles during the early response to a respiratory γHV68 infection. γHV68 infection inhibits type I IFN production by dendritic cells and is a poor inducer of IFN-α/β in vivo, which may serve as an immune evasion strategy.

ID: 132: LUPUS KERATINOCYTES ARE PRIMED BY AN AUTOCRINE TYPE I INTERFERON LOOP TO ROBUSTLY SECRETE IL-6

2016 ◽  
Vol 64 (4) ◽  
pp. 976.2-977
Author(s):  
JN Stannard ◽  
TJ Reed ◽  
JM Kahlenberg ◽  
EM Myers ◽  
L Lowe ◽  
...  
Keyword(s):  
Lupus Erythematosus ◽  
Inflammatory Cytokine ◽  
Cutaneous Lupus Erythematosus ◽  
Type I ◽  
Healthy Controls ◽  
University Of Michigan ◽  
Type I Ifn ◽  
Skin Biopsies ◽  
The University ◽  
Cutaneous Lupus

BackgroundCutaneous lupus erythematosus (CLE) is a disfiguring disease that can affect up to 70% of patients with systemic lupus. Treatment modalities are often ineffective and flares are frequent. Interleukin-6 (IL-6) is a pro-inflammatory cytokine which has gotten recent attention in SLE as IL-6 is increased in the serum of active patients and blockade of IL-6 is therapeutic in murine lupus models and phase I human trials. The source of IL-6 in CLE remains unclear.MethodsAll studies were approved by the University of Michigan Internal Review Board (IRB# 72843 and 66116 to JMK). RNA was isolated from formalin fixed, paraffin-embedded biopsies of CLE rashes, which were obtained from the University of Michigan Pathology database. Real-time PCR was used to determine the expression level of the myxovirus (influenza virus) resistance 1 (MX-1) and interleukin-6 (IL6) genes. Biopsies were stained for IL-6 using immunohistochemistry. Skin biopsies were obtained from uninvolved skin of SLE patients with a history of cutaneous involvement or healthy controls followed by isolation and culture of keratinocytes. At confluence, cultures were treated with various concentrations of TLR ligands or UVB and IL-6 release was measured via ELISA. Blockade of type I IFN signaling was completed via monoclonal antibody to the type I IFN receptor.ResultsReal-time PCR analysis of subacute cutaneous lupus erythematosus (sCLE) (n=21) and discoid (DLE) (n=22) rashes demonstrated a significant upregulation of both the IFN-regulated gene, MX1, and the pro-inflammatory cytokine IL-6 when compared with control samples (n=9). Immunohistochemical analysis of skin biopsies confirmed upregulation of IL-6 in the epidermis when compared to control. Keratinocytes from healthy skin of lupus patients produced significantly more IL-6 when stimulated by TLR2, 3 or 4 agonists or exposed to UVB radiation when compared to identical passage keratinocytes from healthy controls. Treatment of control keratinocytes with IFNα increased their IL-6 production and blockade of type I IFNs in the culture media of SKE keratinocytes downregulated the secretion of IL-6.ConclusionsIL-6 is increased at the RNA and protein level within cutaneous lupus biopsies when compared to healthy control skin. Keratinocytes are a major producer of IL-6 in the skin and lupus keratinocytes have enhanced production of IL-6 in response to TLR ligands and UV radiation. Exposure to type I IFN can increase IL-6 production in keratinocytes. SLE-derived keratinocytes downregulate IL-6 production in the presence of tonic blockade of the type I IFN receptor. These data suggest that the epidermis, which is an important barrier for environmental insults, is primed for IL-6 production by autocrine type I IFN production and that this may be one mechanism by which factors such as UV exposure may trigger rash development. Further investigations should focus on the pathogenic significance of IL-6 upregulation in the skin and whether targeting this pathway will have an impact on cutaneous disease activity.

scholarly journals Photosensitivity and type I IFN responses in cutaneous lupus are driven by epidermal-derived interferon kappa

2018 ◽  
Vol 77 (11) ◽  
pp. 1653-1664 ◽  
Author(s):  
Mrinal K Sarkar ◽  
Grace A Hile ◽  
Lam C Tsoi ◽  
Xianying Xing ◽  
Jianhua Liu ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Lupus Erythematosus ◽  
Cutaneous Lupus Erythematosus ◽  
Ultraviolet B ◽  
Immunofluorescent Staining ◽  
Tunel Staining ◽  
Type I ◽  
Type I Ifn ◽  
Cutaneous Lupus

ObjectiveSkin inflammation and photosensitivity are common in patients with cutaneous lupus erythematosus (CLE) and systemic lupus erythematosus (SLE), yet little is known about the mechanisms that regulate these traits. Here we investigate the role of interferon kappa (IFN-κ) in regulation of type I interferon (IFN) and photosensitive responses and examine its dysregulation in lupus skin.MethodsmRNA expression of type I IFN genes was analysed from microarray data of CLE lesions and healthy control skin. Similar expression in cultured primary keratinocytes, fibroblasts and endothelial cells was analysed via RNA-seq. IFNK knock-out (KO) keratinocytes were generated using CRISPR/Cas9. Keratinocytes stably overexpressing IFN-κ were created via G418 selection of transfected cells. IFN responses were assessed via phosphorylation of STAT1 and STAT2 and qRT-PCR for IFN-regulated genes. Ultraviolet B-mediated apoptosis was analysed via TUNEL staining. In vivo protein expression was assessed via immunofluorescent staining of normal and CLE lesional skin.ResultsIFNK is one of two type I IFNs significantly increased (1.5-fold change, false discovery rate (FDR) q<0.001) in lesional CLE skin. Gene ontology (GO) analysis showed that type I IFN responses were enriched (FDR=6.8×10−04) in keratinocytes not in fibroblast and endothelial cells, and this epithelial-derived IFN-κ is responsible for maintaining baseline type I IFN responses in healthy skin. Increased levels of IFN-κ, such as seen in SLE, amplify and accelerate responsiveness of epithelia to IFN-α and increase keratinocyte sensitivity to UV irradiation. Notably, KO of IFN-κ or inhibition of IFN signalling with baricitinib abrogates UVB-induced apoptosis.ConclusionCollectively, our data identify IFN-κ as a critical IFN in CLE pathology via promotion of enhanced IFN responses and photosensitivity. IFN-κ is a potential novel target for UVB prophylaxis and CLE-directed therapy.

scholarly journals Type I interferon dependence of plasmacytoid dendritic cell activation and migration

2005 ◽  
Vol 201 (7) ◽  
pp. 1157-1167 ◽  
Author(s):  
Carine Asselin-Paturel ◽  
Géraldine Brizard ◽  
Karine Chemin ◽  
Andre Boonstra ◽  
Anne O'Garra ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Activation ◽  
Type I Interferon ◽  
Ex Vivo ◽  
Plasmacytoid Dendritic Cell ◽  
Type I ◽  
Cell Area ◽  
Type I Ifn ◽  
And Migration

Differential expression of Toll-like receptor (TLR) by conventional dendritic cells (cDCs) and plasmacytoid DC (pDCs) has been suggested to influence the type of immune response induced by microbial pathogens. In this study we show that, in vivo, cDCs and pDCs are equally activated by TLR4, -7, and -9 ligands. Type I interferon (IFN) was important for pDC activation in vivo in response to all three TLR ligands, whereas cDCs required type I IFN signaling only for TLR9- and partially for TLR7-mediated activation. Although TLR ligands induced in situ migration of spleen cDC into the T cell area, spleen pDCs formed clusters in the marginal zone and in the outer T cell area 6 h after injection of TLR9 and TLR7 ligands, respectively. In vivo treatment with TLR9 ligands decreased pDC ability to migrate ex vivo in response to IFN-induced CXCR3 ligands and increased their response to CCR7 ligands. Unlike cDCs, the migration pattern of pDCs required type I IFN for induction of CXCR3 ligands and responsiveness to CCR7 ligands. These data demonstrate that mouse pDCs differ from cDCs in the in vivo response to TLR ligands, in terms of pattern and type I IFN requirement for activation and migration.

scholarly journals OP0005 ELEVATED STAT1 EXPRESSION BUT NOT PHOSPHORYLATION IN LUPUS B CELLS CORRELATES WITH DISEASE ACTIVITY AND INCREASED PLASMABLAST SUSCEPTIBILITY

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 4-5
Author(s):  
A. Aue ◽  
F. Szelinski ◽  
S. Weißenberg ◽  
A. Wiedemann ◽  
T. Rose ◽  
...  
Keyword(s):  
Systemic Lupus Erythematosus ◽  
B Cells ◽  
Autoimmune Diseases ◽  
Disease Activity ◽  
B Cell ◽  
Lupus Erythematosus ◽  
Type I ◽  
Type I Ifn ◽  
Systemic Lupus ◽  
B Cell Subsets

Background:Systemic lupus erythematosus (SLE) is characterized by two pathogenic key signatures, type I interferon (IFN) (1.) and B-cell abnormalities (2.). How these signatures are interrelated is not known. Type I-II IFN trigger activation of Janus kinase (JAK) – signal transducer and activator of transcription (STAT).Objectives:JAK-STAT inhibition is an attractive therapeutic possibility for SLE (3.). We assess STAT1 and STAT3 expression and phosphorylation at baseline and after IFN type I and II stimulation in B-cell subpopulations of SLE patients compared to other autoimmune diseases and healthy controls (HD) and related it to disease activity.Methods:Expression of STAT1, pSTAT1, STAT3 and pSTAT3 in B and T-cells of 21 HD, 10 rheumatoid arthritis (RA), 7 primary Sjögren’s (pSS) and 22 SLE patients was analyzed by flow cytometry. STAT1 and STAT3 expression and phosphorylation in PBMCs of SLE patients and HD after IFNα and IFNγ incubation were further investigated.Results:SLE patients showed substantially higher STAT1 but not pSTAT1 in B and T-cell subsets. Increased STAT1 expression in B cell subsets correlated significantly with SLEDAI and Siglec-1 on monocytes, a type I IFN marker (4.). STAT1 activation in plasmablasts was IFNα dependent while monocytes exhibited dependence on IFNγ.Figure 1.Significantly increased expression of STAT1 by SLE B cells(A) Representative histograms of baseline expression of STAT1, pSTAT1, STAT3 and pSTAT3 in CD19+ B cells of SLE patients (orange), HD (black) and isotype controls (grey). (B) Baseline expression of STAT1 and pSTAT1 or (C) STAT3 and pSTAT3 in CD20+CD27-, CD20+CD27+ and CD20lowCD27high B-lineage cells from SLE (orange) patients compared to those from HD (black). Mann Whitney test; ****p≤0.0001.Figure 2.Correlation of STAT1 expression by SLE B cells correlates with type I IFN signature (Siglec-1, CD169) and clinical activity (SLEDAI).Correlation of STAT1 expression in CD20+CD27- näive (p<0.0001, r=0.8766), CD20+CD27+ memory (p<0.0001, r=0.8556) and CD20lowCD27high (p<0.0001, r=0.9396) B cells from SLE patients with (A) Siglec-1 (CD169) expression on CD14+ cells as parameter of type I IFN signature and (B) lupus disease activity (SLEDAI score). Spearman rank coefficient (r) was calculated to identify correlations between these parameters. *p≤0.05, **p≤0.01. (C) STAT1 expression in B cell subsets of a previously undiagnosed, active SLE patient who was subsequently treated with two dosages of prednisolone and reanalyzed.Conclusion:Enhanced expression of STAT1 by B-cells candidates as key node of two immunopathogenic signatures (type I IFN and B-cells) related to important immunopathogenic pathways and lupus activity. We show that STAT1 is activated upon IFNα exposure in SLE plasmablasts. Thus, Jak inhibitors, targeting JAK-STAT pathways, hold promise to block STAT1 expression and control plasmablast induction in SLE.References:[1]Baechler EC, Batliwalla FM, Karypis G, Gaffney PM, Ortmann WA, Espe KJ, et al. Interferon-inducible gene expression signature in peripheral blood cells of patients with severe lupus. Proc Natl Acad Sci U S A. 2003;100(5):2610-5.[2]Lino AC, Dorner T, Bar-Or A, Fillatreau S. Cytokine-producing B cells: a translational view on their roles in human and mouse autoimmune diseases. Immunol Rev. 2016;269(1):130-44.[3]Dorner T, Lipsky PE. Beyond pan-B-cell-directed therapy - new avenues and insights into the pathogenesis of SLE. Nat Rev Rheumatol. 2016;12(11):645-57.[4]Biesen R, Demir C, Barkhudarova F, Grun JR, Steinbrich-Zollner M, Backhaus M, et al. Sialic acid-binding Ig-like lectin 1 expression in inflammatory and resident monocytes is a potential biomarker for monitoring disease activity and success of therapy in systemic lupus erythematosus. Arthritis Rheum. 2008;58(4):1136-45.Disclosure of Interests:Arman Aue: None declared, Franziska Szelinski: None declared, Sarah Weißenberg: None declared, Annika Wiedemann: None declared, Thomas Rose: None declared, Andreia Lino: None declared, Thomas Dörner Grant/research support from: Janssen, Novartis, Roche, UCB, Consultant of: Abbvie, Celgene, Eli Lilly, Roche, Janssen, EMD, Speakers bureau: Eli Lilly, Roche, Samsung, Janssen

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