Publications by authors named "Florian C Kurschus"

44 Publications

Laquinimod dampens IL-1β signaling and Th17-polarizing capacity of monocytes in patients with MS.

Neurol Neuroimmunol Neuroinflamm 2021 01 17;8(1). Epub 2020 Nov 17.

From the Department of Neurology (S.E., V.J., S.H.-P.K., K.R., F.L.), Focus Program Translational Neuroscience (FTN), University Medical Center of the Johannes Gutenberg University of Mainz, Germany; Biopathology of Myelin (V.J.), Neuroprotection and Therapeutic Strategy, INSERM U1119, Fédération de Médecine Translationnelle de Strasbourg (FMTS), University of Strasbourg, France; Institute for Molecular Medicine (M.Z., F.C.K., A.W.), University Medical Centre of the Johannes Gutenberg University of Mainz, Germany; Sheba Cancer Research Center (M.Z.), Chaim Sheba Academic Medical Center, Ramat Gan, Israel; Department of Neurology (H.T.), University of Ulm, Germany and Specialty Clinic of Neurology Dietenbronn, Schwendi, Germany; Clinical Neuroimmunology Unit (R.F.), San Raffaele Scientific Institute, Milan, Italy; and Department of Dermatology (F.C.K.), Heidelberg University Hospital, Heidelberg, Germany.

Objective: To assess the impact of laquinimod treatment on monocytes and to investigate the underlying immunomodulatory mechanisms in MS.

Methods: In this cross-sectional study, we performed in vivo and in vitro analyses of cluster of differentiation (CD14) monocytes isolated from healthy donors (n = 15), untreated (n = 13), and laquinimod-treated patients with MS (n = 14). Their frequency and the expression of surface activation markers were assessed by flow cytometry and the viability by calcein staining. Cytokine concentrations in the supernatants of lipopolysaccharide (LPS)-stimulated monocytes were determined by flow cytometry. The messenger ribonucleic acid (mRNA) expression level of genes involved in cytokine expression was measured by quantitative PCR. The LPS-mediated nuclear factor kappa-light-chain-enhancer of activated B-cell (NF-κB) activation was determined by the quantification of the phosphorylation level of the p65 subunit. Laquinimod-treated monocytes were cocultured with CD4 T cells, and the resulting cytokine production was analyzed by flow cytometry after intracellular cytokine staining. The interleukin (IL)-17A concentration of the supernatant was assessed by ELISA.

Results: Laquinimod did not alter the frequency or viability of circulating monocytes, but led to an upregulation of CD86 expression. LPS-stimulated monocytes of laquinimod-treated patients with MS secreted less IL-1β following a downregulation of IL-1β gene expression. Phosphorylation levels of the NF-κB p65 subunit were reduced after laquinimod treatment, indicating a laquinimod-associated inhibition of the NF-κB pathway. T cells primed with laquinimod-treated monocytes differentiated significantly less into IL-17A-producing T helper (Th)-17 cells.

Conclusions: Our findings suggest that inhibited NF-κB signaling and downregulation of IL-1β expression in monocytes contributes to the immunomodulatory effects of laquinimod and that the impairment of Th17 polarization might mediate its disease-modifying activity in MS.
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http://dx.doi.org/10.1212/NXI.0000000000000908DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7676421PMC
January 2021

Interleukin-1 promotes autoimmune neuroinflammation by suppressing endothelial heme oxygenase-1 at the blood-brain barrier.

Acta Neuropathol 2020 10 11;140(4):549-567. Epub 2020 Jul 11.

Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany.

The proinflammatory cytokine interleukin 1 (IL-1) is crucially involved in the pathogenesis of multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE). Herein, we studied the role of IL-1 signaling in blood-brain barrier (BBB) endothelial cells (ECs), astrocytes and microglia for EAE development, using mice with the conditional deletion of its signaling receptor IL-1R1. We found that IL-1 signaling in microglia and astrocytes is redundant for the development of EAE, whereas the IL-1R1 deletion in BBB-ECs markedly ameliorated disease severity. IL-1 signaling in BBB-ECs upregulated the expression of the adhesion molecules Vcam-1, Icam-1 and the chemokine receptor Darc, all of which have been previously shown to promote CNS-specific inflammation. In contrast, IL-1R1 signaling suppressed the expression of the stress-responsive heme catabolizing enzyme heme oxygenase-1 (HO-1) in BBB-ECs, promoting disease progression via a mechanism associated with deregulated expression of the IL-1-responsive genes Vcam1, Icam1 and Ackr1 (Darc). Mechanistically, our data emphasize a functional crosstalk of BBB-EC IL-1 signaling and HO-1, controlling the transcription of downstream proinflammatory genes promoting the pathogenesis of autoimmune neuroinflammation.
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http://dx.doi.org/10.1007/s00401-020-02187-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7498485PMC
October 2020

Review-Current Concepts in Inflammatory Skin Diseases Evolved by Transcriptome Analysis: In-Depth Analysis of Atopic Dermatitis and Psoriasis.

Int J Mol Sci 2020 Jan 21;21(3). Epub 2020 Jan 21.

Department of Dermatology, Heidelberg University Hospital, 69120 Heidelberg, Germany.

During the last decades, high-throughput assessment of gene expression in patient tissues using microarray technology or RNA-Seq took center stage in clinical research. Insights into the diversity and frequency of transcripts in healthy and diseased conditions provide valuable information on the cellular status in the respective tissues. Growing with the technique, the bioinformatic analysis toolkit reveals biologically relevant pathways which assist in understanding basic pathophysiological mechanisms. Conventional classification systems of inflammatory skin diseases rely on descriptive assessments by pathologists. In contrast to this, molecular profiling may uncover previously unknown disease classifying features. Thereby, treatments and prognostics of patients may be improved. Furthermore, disease models in basic research in comparison to the human disease can be directly validated. The aim of this article is not only to provide the reader with information on the opportunities of these techniques, but to outline potential pitfalls and technical limitations as well. Major published findings are briefly discussed to provide a broad overview on the current findings in transcriptomics in inflammatory skin diseases.
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http://dx.doi.org/10.3390/ijms21030699DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7037913PMC
January 2020

IL-17 CD8 T cell suppression by dimethyl fumarate associates with clinical response in multiple sclerosis.

Nat Commun 2019 12 16;10(1):5722. Epub 2019 Dec 16.

Institute for Medical Microbiology and Hospital Hygiene, University of Marburg, 35043, Marburg, Germany.

IL-17-producing CD8 (Tc17) cells are enriched in active lesions of patients with multiple sclerosis (MS), suggesting a role in the pathogenesis of autoimmunity. Here we show that amelioration of MS by dimethyl fumarate (DMF), a mechanistically elusive drug, associates with suppression of Tc17 cells. DMF treatment results in reduced frequency of Tc17, contrary to Th17 cells, and in a decreased ratio of the regulators RORC-to-TBX21, along with a shift towards cytotoxic T lymphocyte gene expression signature in CD8 T cells from MS patients. Mechanistically, DMF potentiates the PI3K-AKT-FOXO1-T-BET pathway, thereby limiting IL-17 and RORγt expression as well as STAT5-signaling in a glutathione-dependent manner. This results in chromatin remodeling at the Il17 locus. Consequently, T-BET-deficiency in mice or inhibition of PI3K-AKT, STAT5 or reactive oxygen species prevents DMF-mediated Tc17 suppression. Overall, our data disclose a DMF-AKT-T-BET driven immune modulation and suggest putative therapy targets in MS and beyond.
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http://dx.doi.org/10.1038/s41467-019-13731-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6915776PMC
December 2019

Dietary tryptophan links encephalogenicity of autoreactive T cells with gut microbial ecology.

Nat Commun 2019 10 25;10(1):4877. Epub 2019 Oct 25.

DKTK Clinical Cooperation Unit Neuroimmunology and Brain Tumor Immunology, German Cancer Research Center (DKFZ), Heidelberg, Germany.

The interaction between the mammalian host and its resident gut microbiota is known to license adaptive immune responses. Nutritional constituents strongly influence composition and functional properties of the intestinal microbial communities. Here, we report that omission of a single essential amino acid - tryptophan - from the diet abrogates CNS autoimmunity in a mouse model of multiple sclerosis. Dietary tryptophan restriction results in impaired encephalitogenic T cell responses and is accompanied by a mild intestinal inflammatory response and a profound phenotypic shift of gut microbiota. Protective effects of dietary tryptophan restriction are abrogated in germ-free mice, but are independent of canonical host sensors of intracellular tryptophan metabolites. We conclude that dietary tryptophan restriction alters metabolic properties of gut microbiota, which in turn have an impact on encephalitogenic T cell responses. This link between gut microbiota, dietary tryptophan and adaptive immunity may help to develop therapeutic strategies for protection from autoimmune neuroinflammation.
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http://dx.doi.org/10.1038/s41467-019-12776-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6814758PMC
October 2019

Keratinocyte-derived IκBζ drives psoriasis and associated systemic inflammation.

JCI Insight 2019 11 14;4(22). Epub 2019 Nov 14.

Interfaculty Institute for Biochemistry, University of Tübingen, Tübingen, Germany.

The transcriptional activator IκBζ is a key regulator of psoriasis, but which cells mediate its pathogenic effect remains unknown. Here we found that IκBζ expression in keratinocytes triggers not only skin lesions but also systemic inflammation in mouse psoriasis models. Specific depletion of IκBζ in keratinocytes was sufficient to suppress the induction of imiquimod- or IL-36-mediated psoriasis. Moreover, IκBζ ablation in keratinocytes prevented the onset of psoriatic lesions and systemic inflammation in keratinocyte-specific IL-17A-transgenic mice. Mechanistically, this psoriasis protection was mediated by IκBζ deficiency in keratinocytes abrogating the induction of specific proinflammatory target genes, including Cxcl5, Cxcl2, Csf2, and Csf3, in response to IL-17A or IL-36. These IκBζ-dependent genes trigger the generation and recruitment of neutrophils and monocytes that are needed for skin inflammation. Consequently, our data uncover a surprisingly pivotal role of keratinocytes and keratinocyte-derived IκBζ as key mediators of psoriasis and psoriasis-related systemic inflammation.
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http://dx.doi.org/10.1172/jci.insight.130835DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6948851PMC
November 2019

Dimethyl fumarate alters intracellular Ca handling in immune cells by redox-mediated pleiotropic effects.

Free Radic Biol Med 2019 09 4;141:338-347. Epub 2019 Jul 4.

Institute of Molecular Medicine, University Medical Center of the Johannes Gutenberg-Universität Mainz, Mainz, Germany. Electronic address:

Dimethyl fumarate (DMF) is widely used to treat the human autoimmune diseases multiple sclerosis (MS) and psoriasis. DMF causes short-term oxidative stress and activates the antioxidant response via the transcription factor Nrf2 but its immunosuppressive effect is not well understood. Immune cell activation depends on calcium signaling which itself is influenced by the cellular redox state. We therefore measured calcium, reactive oxygen species levels and glutathione content in lymphocytes from immunized mice before onset of experimental autoimmune encephalomyelitis, in peripheral blood mononuclear cells from MS patients treated with DMF, and in mouse splenocytes treated ex vivo with DMF. This demonstrated altered redox states and increased lymphocytic calcium levels in all model systems. DMF caused an immediate influx of calcium from the extracellular space, long-term increased cytosolic calcium levels and reduced calcium stored in intracellular stores. The DMF-elicited current had the electrophysiological characteristics of a transient receptor potential channel and the intracellular calcium levels were normalized by antagonists of TRPA1. Interestingly, the sarco/endoplasmic reticulum Ca-ATPase SERCA2b was downregulated but more active due to glutathionylation of the redox-sensitive cysteine 674. DMF therefore causes pleiotropic changes in cellular calcium homeostasis which are likely caused by redox-sensitive post-translational modifications. These changes probably contribute to its immunosuppressive effects.
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http://dx.doi.org/10.1016/j.freeradbiomed.2019.07.005DOI Listing
September 2019

Lugdunin amplifies innate immune responses in the skin in synergy with host- and microbiota-derived factors.

Nat Commun 2019 06 21;10(1):2730. Epub 2019 Jun 21.

Department of Dermatology, University of Tübingen, Liebermeisterstraße 25, 72076, Tübingen, Germany.

Recently our groups discovered lugdunin, a new cyclic peptide antibiotic that inhibits Staphylococcus aureus epithelial colonization in humans and rodents. In this work, we analyzed its immuno-modulatory and antimicrobial potential as a single agent or in combination with other microbiota- or host-derived factors. We show that pretreatment of primary human keratinocytes or mouse skin with lugdunin in combination with microbiota-derived factors results in a significant reduction of S. aureus colonization. Moreover, lugdunin increases expression and release of LL-37 and CXCL8/MIP-2 in human keratinocytes and mouse skin, and results in the recruitment of monocytes and neutrophils in vivo, both by a TLR/MyD88-dependent mechanism. Interestingly, S. aureus elimination by lugdunin is additionally achieved by synergistic antimicrobial activity with LL-37 and dermcidin-derived peptides. In summary, our results indicate that lugdunin provides multi-level protection against S. aureus and may thus become a promising treatment option for S. aureus skin infections in the future.
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http://dx.doi.org/10.1038/s41467-019-10646-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6588697PMC
June 2019

Imiquimod-Induced Psoriasis in Mice Depends on the IL-17 Signaling of Keratinocytes.

J Invest Dermatol 2019 05 23;139(5):1110-1117. Epub 2019 Jan 23.

Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany; Department of Dermatology, Heidelberg University Hospital, Heidelberg, Germany. Electronic address:

The pathology of psoriasis strongly depends on IL-17A. Monoclonal antibodies blocking either the cytokine or its receptor are among the most efficient treatments for psoriatic patients. Keratinocytes can be activated upon exposure to IL-17A and tumor necrosis factor-α and secrete secondary cytokines and chemokines in the inflamed skin. In psoriasis and its imiquimod-induced mouse model, a strong skin infiltration of neutrophils and inflammatory monocytes can be observed. However, to date, it is not clear how exactly those cellular populations are attracted to the skin and how they contribute to the pathogenesis of the disease. To define the crucial cell type responding to IL-17 and initiating the downstream pathology in psoriasis-like dermatitis, we used mice specifically lacking the IL-17 receptor (IL-17RA) in different cell types. Deletion of IL-17RA in T cells or myeloid had no impact on disease development. Only deletion of this receptor in keratinocytes reflected the full-body deletion of IL-17RA, resulting in strongly reduced dermatitis development. Imiquimod treatment of those IL-17 signaling-deficient mice maintained high monocytic infiltration but failed to attract neutrophils into the skin. We conclude that keratinocytes are a critical cellular target for IL-17A-mediated neutrophil attraction and psoriasis development.
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http://dx.doi.org/10.1016/j.jid.2019.01.006DOI Listing
May 2019

Alternative Splice Forms of CYLD Mediate Ubiquitination of SMAD7 to Prevent TGFB Signaling and Promote Colitis.

Gastroenterology 2019 02 10;156(3):692-707.e7. Epub 2018 Oct 10.

Institute for Molecular Medicine, University Medical Centre, Johannes Gutenberg University of Mainz, Mainz, Germany. Electronic address:

Background & Aims: The CYLD lysine 63 deubiquitinase gene (CYLD) encodes tumor suppressor protein that is mutated in familial cylindromatosus, and variants have been associated with Crohn disease (CD). Splice forms of CYLD that lack exons 7 and 8 regulate transcription factors and functions of immune cells. We examined the expression of splice forms of CYLD in colon tissues from patients with CD and their effects in mice.

Methods: We performed immunohistochemical analyses of colon tissues from patients with untreated CD and patients without inflammatory bowel diseases (controls). We obtained mice that expressed splice forms of CYLD (sCYLD mice) without or with SMAD7 (sCYLD/SMAD7 mice) from transgenes and CYLD-knockout mice (with or without transgenic expression of SMAD7) and performed endoscopic analyses. Colitis was induced in Rag1 mice by transfer of CD4 CD62L T cells from C57/Bl6 or transgenic mice. T cells were isolated from mice and analyzed by flow cytometry and quantitative real-time polymerase chain reaction and intestinal tissues were analyzed by histology and immunohistochemistry. CYLD forms were expressed in mouse embryonic fibroblasts, primary T cells, and HEK293T cells, which were analyzed by immunoblot, mobility shift, and immunoprecipitation assays.

Results: The colonic lamina propria from patients with CD was infiltrated by T cells and had higher levels of sCYLD (but not full-length CYLD) and SMAD7 than tissues from controls. Incubation of mouse embryonic fibroblasts and T cells with transforming growth factor β increased their production of sCYLD and decreased full-length CYLD. Transgenic expression of sCYLD and SMAD7 in T cells prevented the differentiation of regulatory T cells and T-helper type 17 cells and increased the differentiation of T-helper type 1 cells. The same effects were observed in colon tissues from sCYLD/SMAD7 mice but not in those from CYLD-knockout SMAD7 mice. The sCYLD mice had significant increases in the numbers of T-helper type 1 cells and CD44 CD62L memory-effector CD4 T cells in the spleen and mesenteric lymph nodes compared with wild-type mice; sCYLD/SMAD7 mice had even larger increases. The sCYLD/SMAD7 mice spontaneously developed severe colitis, with infiltration of the colon by dendritic cells, neutrophils, macrophages, and CD4 T cells and increased levels of Ifng, Il6, Il12a, Il23a, and Tnf mRNAs. Co-transfer of regulatory T cells from wild-type, but not from sCYLD/SMAD7, mice prevented the induction of colitis in Rag1 mice by CD4 T cells. We found increased levels of poly-ubiquitinated SMAD7 in sCYLD CD4 T cells. CYLD formed a nuclear complex with SMAD3, whereas sCYLD recruited SMAD7 to the nucleus, which inhibited the expression of genes regulated by SMAD3 and SMAD4. We found that sCYLD mediated lysine 63-linked ubiquitination of SMAD7. The sCYLD-SMAD7 complex inhibited transforming growth factor β signaling in CD4 T cells.

Conclusions: Levels of the spliced form of CYLD are increased in colon tissues from patients with CD. sCYLD mediates ubiquitination and nuclear translocation of SMAD7 and thereby decreases transforming growth factor β signaling in T cells. This prevents immune regulatory mechanisms and leads to colitis in mice.
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http://dx.doi.org/10.1053/j.gastro.2018.10.023DOI Listing
February 2019

NF-κB inducing kinase (NIK) is an essential post-transcriptional regulator of T-cell activation affecting F-actin dynamics and TCR signaling.

J Autoimmun 2018 11 29;94:110-121. Epub 2018 Jul 29.

Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany. Electronic address:

NF-κB inducing kinase (NIK) is the key protein of the non-canonical NF-κB pathway and is important for the development of lymph nodes and other secondary immune organs. We elucidated the specific role of NIK in T cells using T-cell specific NIK-deficient (NIK) mice. Despite showing normal development of lymphoid organs, NIK mice were resistant to induction of CNS autoimmunity. T cells from NIK mice were deficient in late priming, failed to up-regulate T-bet and to transmigrate into the CNS. Proteomic analysis of activated NIK T cells showed de-regulated expression of proteins involved in the formation of the immunological synapse: in particular, proteins involved in cytoskeleton dynamics. In line with this we found that NIK-deficient T cells were hampered in phosphorylation of Zap70, LAT, AKT, ERK1/2 and PLCγ upon TCR engagement. Hence, our data disclose a hitherto unknown function of NIK in T-cell priming and differentiation.
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http://dx.doi.org/10.1016/j.jaut.2018.07.017DOI Listing
November 2018

The actin remodeling protein cofilin is crucial for thymic αβ but not γδ T-cell development.

PLoS Biol 2018 07 9;16(7):e2005380. Epub 2018 Jul 9.

Institute of Immunology, University of Heidelberg, Heidelberg, Germany.

Cofilin is an essential actin remodeling protein promoting depolymerization and severing of actin filaments. To address the relevance of cofilin for the development and function of T cells in vivo, we generated knock-in mice in which T-cell-specific nonfunctional (nf) cofilin was expressed instead of wild-type (WT) cofilin. Nf cofilin mice lacked peripheral αβ T cells and showed a severe thymus atrophy. This was caused by an early developmental arrest of thymocytes at the double negative (DN) stage. Importantly, even though DN thymocytes expressed the TCRβ chain intracellularly, they completely lacked TCRβ surface expression. In contrast, nf cofilin mice possessed normal numbers of γδ T cells. Their functionality was confirmed in the γδ T-cell-driven, imiquimod (IMQ)-induced, psoriasis-like murine model. Overall, this study not only highlights the importance of cofilin for early αβ T-cell development but also shows for the first time that an actin-binding protein is differentially involved in αβ versus γδ T-cell development.
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http://dx.doi.org/10.1371/journal.pbio.2005380DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6053251PMC
July 2018

Expression of IL-17F is associated with non-pathogenic Th17 cells.

J Mol Med (Berl) 2018 08 29;96(8):819-829. Epub 2018 Jun 29.

University Medical Center of the Johannes Gutenberg University Mainz, Institute for Molecular Medicine, 55131, Mainz, Germany.

IL-17A and IL-17F share the highest sequence homology of the IL-17 family and signal via the same IL-17RA/RC receptor heterodimer. To better explore the expression of these two cytokines, we used a double reporter mouse strain (IL-17 mice), where IL-17A expressing cells are marked by enhanced green fluorescent protein (eGFP) while red fluorescence protein (RFP) reports the expression of IL-17F. In steady state, we found that Th17 and γδ T cells only expressed IL-17A, while IL-17F expression was restricted to CD8 T cells (Tc17) and innate lymphoid cells (ILC type 3) of the gut. In experimental autoimmune encephalomyelitis, the vast majority of CNS-infiltrating Th17 cells expressed IL-17A but not IL-17F. In contrast, anti-CD3-induced, TGF-β-driven Th17 cells in the gut expressed both of these IL-17 cytokines. In line with this, in vitro differentiation of Th17 cells in the presence of IL-1β led primarily to IL-17A expressing T cells, while TGF-β induced IL-17F co-expressing Th17 cells. Our results suggest that expression of IL-17F is associated with non-pathogenic T cells, pointing to a differential function of IL-17A versus IL-17F.

Key Messages: Naïve mice: CD4 T cells and γδ T cells express IL-17A, and Tc17 cells express IL-17F. Gut ILC3 show differential expression of IL17A and F. Th17 differentiation with TGF-β1 induces IL-17A and F, whereas IL-1β induced cells expressing IL-17A. Th17 cells in EAE in CNS express IL-17A only. Gut Th17 cells induced by anti-CD3 express IL-17A and F together as skin γδ T cells of IMQ-treated mice.
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http://dx.doi.org/10.1007/s00109-018-1662-5DOI Listing
August 2018

EBI2 - Sensor for dihydroxycholesterol gradients in neuroinflammation.

Biochimie 2018 Oct 22;153:52-55. Epub 2018 Apr 22.

Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany.

Dihydroxycholesterols such as 7α,25-dihydroxysterols (7α,25-OHC) and 7α,27-OHC are generated from cholesterol by the enzymes CH25H, CYP7B1 and CYP27A1 in steady state but also in the context of inflammation. The G-protein coupled receptor (GPCR) Epstein-Barr virus-induced gene 2 (EBI2), also known as GPR183, senses these oxysterols and induces chemotactic migration of immune cells towards higher concentrations of these ligands. We recently showed that these ligands are upregulated in the CNS in experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis and that EBI2 enhanced early infiltration of encephalitogenic T cells into the CNS. In this short-review we discuss the role of dihydroxysterol-sensing by immune cells in neuroinflammation.
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http://dx.doi.org/10.1016/j.biochi.2018.04.014DOI Listing
October 2018

Regulation of IL-22BP in psoriasis.

Sci Rep 2018 03 23;8(1):5085. Epub 2018 Mar 23.

Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany.

IL-22 is a potent pro-inflammatory cytokine upregulated in psoriasis and in other inflammatory diseases. The function of IL-22 is regulated by the soluble scavenging receptor, IL-22 binding protein (IL-22BP or IL-22RA2). However, the role and regulation of IL-22BP itself in the pathogenesis of inflammatory disease remain unclear. We used the TLR7 agonist Imiquimod (IMQ) to induce a psoriasis-like skin disease in mice and found a strong downregulation of IL-22BP in the affected skin as well as in the lymph nodes of animals treated with IMQ. We also analysed psoriatic skin of patients and compared this to skin of healthy donors. Interestingly, IL-22BP expression was similarly downregulated in skin biopsies of psoriasis patients compared to the skin of healthy donors. Since IL-22BP is expressed foremost in dendritic cells, we characterized its expression in monocyte-derived dendritic cells (MoDC) during maturation. In this way, we found Prostaglandin E2 (PGE) to be a potent suppressor of IL-22BP expression in vitro. We conclude that regulation of IL-22BP by inflammatory mediators is an important step for the progression of inflammation in the skin and possibly also in other autoimmune diseases.
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http://dx.doi.org/10.1038/s41598-018-23510-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5865214PMC
March 2018

Single-cell profiling reveals GPCR heterogeneity and functional patterning during neuroinflammation.

JCI Insight 2017 Aug 3;2(15). Epub 2017 Aug 3.

Department of Pharmacology.

GPCR expression was intensively studied in bulk cDNA of leukocyte populations, but limited data are available with respect to expression in individual cells. Here, we show a microfluidic-based single-cell GPCR expression analysis in primary T cells, myeloid cells, and endothelial cells under naive conditions and during experimental autoimmune encephalomyelitis, the mouse model of multiple sclerosis. We found that neuroinflammation induces characteristic changes in GPCR heterogeneity and patterning, and we identify various functionally relevant subgroups with specific GPCR profiles among spinal cord-infiltrating CD4 T cells, macrophages, microglia, or endothelial cells. Using GPCRs CXCR4, S1P1, and LPHN2 as examples, we show how this information can be used to develop new strategies for the functional modulation of Th17 cells and activated endothelial cells. Taken together, single-cell GPCR expression analysis identifies functionally relevant subpopulations with specific GPCR repertoires and provides a basis for the development of new therapeutic strategies in immune disorders.
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http://dx.doi.org/10.1172/jci.insight.95063DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5543912PMC
August 2017

IL-17 for therapy.

J Dermatol Sci 2017 Sep 15;87(3):221-227. Epub 2017 Jun 15.

Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, 55131, Germany.

The cytokine IL-17 is now a target for an array of therapeutic monoclonal antibodies supposed to treat a variety of inflammatory diseases. The forerunner Secukinumab, an IL-17A neutralizing antibody, is meanwhile approved as first-line treatments for moderate-to-severe plaque psoriasis, and as second-line treatment for psoriatic arthritis and ankylosing spondylitis. Ixekizumab and Brodalumab, both also targeting the IL-17 pathway, were also recently approved by the FDA for plaque psoriasis. Using mice overexpressing IL-17A in a tissue of choice, we showed that the ectopic expression of this cytokine in keratinocytes resulted in a spontaneous and very strong form of psoriasis-like dermatitis. Interestingly, this model showed some typical comorbidities found in humans with psoriasis. In this review, we will discuss why IL-17 is a good target especially in psoriasis and what we learned from mouse models about its functions in pathological situations.
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http://dx.doi.org/10.1016/j.jdermsci.2017.06.010DOI Listing
September 2017

NG2 plays a role in neuroinflammation but is not expressed by immune cells.

Acta Neuropathol 2017 08 31;134(2):325-327. Epub 2017 May 31.

Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany.

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http://dx.doi.org/10.1007/s00401-017-1735-5DOI Listing
August 2017

TGF-β inhibitor Smad7 regulates dendritic cell-induced autoimmunity.

Proc Natl Acad Sci U S A 2017 02 6;114(8):E1480-E1489. Epub 2017 Feb 6.

Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg University Mainz, 55131 Mainz, Germany;

TGF-β is an anti-inflammatory cytokine whose signaling is negatively controlled by Smad7. Previously, we established a role for Smad7 in the generation of autoreactive T cells; however, the function of Smad7 in dendritic cells (DCs) remains elusive. Here, we demonstrate that DC-specific Smad7 deficiency resulted in elevated expression of the transcription factors Batf3 and IRF8, leading to increased frequencies of CD8CD103 DCs in the spleen. Furthermore, Smad7-deficient DCs expressed higher levels of indoleamine 2,3-dioxygenase (IDO), an enzyme associated with tolerance induction. Mice devoid of Smad7 specifically in DCs are resistant to the development of experimental autoimmune encephalomyelitis (EAE) as a result of an increase of protective regulatory T cells (Tregs) and reduction of encephalitogenic effector T cells in the central nervous system. In agreement, inhibition of IDO activity or depletion of Tregs restored disease susceptibility. Intriguingly, when Smad7-deficient DCs also lacked the IFN-γ receptor, the mice regained susceptibility to EAE, demonstrating that IFN-γ signaling in DCs mediates their tolerogenic function. Our data indicate that Smad7 expression governs splenic DC subset differentiation and is critical for the promotion of their efficient function in immunity.
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http://dx.doi.org/10.1073/pnas.1615065114DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5338403PMC
February 2017

EBI2 Is Highly Expressed in Multiple Sclerosis Lesions and Promotes Early CNS Migration of Encephalitogenic CD4 T Cells.

Cell Rep 2017 01;18(5):1270-1284

Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg-University Mainz, 55131 Mainz, Germany. Electronic address:

Arrival of encephalitogenic T cells at inflammatory foci represents a critical step in development of experimental autoimmune encephalomyelitis (EAE), the animal model for multiple sclerosis. EBI2 and its ligand, 7α,25-OHC, direct immune cell localization in secondary lymphoid organs. CH25H and CYP7B1 hydroxylate cholesterol to 7α,25-OHC. During EAE, we found increased expression of CH25H by microglia and CYP7B1 by CNS-infiltrating immune cells elevating the ligand concentration in the CNS. Two critical pro-inflammatory cytokines, interleukin-23 (IL-23) and interleukin-1 beta (IL-1β), maintained expression of EBI2 in differentiating Th17 cells. In line with this, EBI2 enhanced early migration of encephalitogenic T cells into the CNS in a transfer EAE model. Nonetheless, EBI2 was dispensable in active EAE. Human Th17 cells do also express EBI2, and EBI2 expressing cells are abundant within multiple sclerosis (MS) white matter lesions. These findings implicate EBI2 as a mediator of CNS autoimmunity and describe mechanistically its contribution to the migration of autoreactive T cells into inflamed organs.
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http://dx.doi.org/10.1016/j.celrep.2017.01.020DOI Listing
January 2017

IL-1 signaling is critical for expansion but not generation of autoreactive GM-CSF+ Th17 cells.

EMBO J 2017 01 8;36(1):102-115. Epub 2016 Nov 8.

Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany

Interleukin-1 (IL-1) is implicated in numerous pathologies, including multiple sclerosis and its animal model experimental autoimmune encephalomyelitis (EAE). However, the exact mechanism by which IL-1 is involved in the generation of pathogenic T cells and in disease development remains largely unknown. We found that following EAE induction, pertussis toxin administration leads to IL-1 receptor type 1 (IL-1R1)-dependent IL-1β expression by myeloid cells in the draining lymph nodes. This myeloid-derived IL-1β did not vitally contribute to the generation and plasticity of Th17 cells, but rather promoted the expansion of a GM-CSF Th17 cell subset, thereby enhancing its encephalitogenic potential. Lack of expansion of GM-CSF-producing Th17 cells led to ameliorated disease in mice deficient for IL-1R1 specifically in T cells. Importantly, pathogenicity of IL-1R1-deficient T cells was fully restored by IL-23 polarization and expansion in vitro Therefore, our data demonstrate that IL-1 functions as a mitogenic mediator of encephalitogenic Th17 cells rather than qualitative inducer of their generation.
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http://dx.doi.org/10.15252/embj.201694615DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5210124PMC
January 2017

T cell mediated pathogenesis in EAE: Molecular mechanisms.

Biomed J 2015 May-Jun;38(3):183-93

Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany.

T cells are major initiators and mediators of disease in multiple sclerosis (MS) and in its animal model experimental autoimmune encephalomyelitis (EAE). EAE is an antigen-driven autoimmune model in which immunization against myelin autoantigens elicits strong T cell responses which initiate its pathology with CNS myelin destruction. T cells cause pathogenic events by several mechanisms; some work in a direct fashion in the CNS, such as direct cytokine-induced damage, granzyme-mediated killing, or glutamate-induced neurotoxicity, whereas most are indirect mechanisms, such as activation of other cell types like macrophages, B cells, or neutrophils. This review aims to describe and discuss the molecular effector mechanism by which T cells harm the CNS during EAE.
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http://dx.doi.org/10.4103/2319-4170.155590DOI Listing
December 2016

Improved method to retain cytosolic reporter protein fluorescence while staining for nuclear proteins.

Cytometry A 2014 Jul 19;85(7):621-7. Epub 2014 Feb 19.

Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg, University of Mainz, 55131, Mainz, Germany.

Staining of transcription factors (TFs) together with retention of fluorescent reporter proteins is hindered by loss of fluorescence using current available methods. In this study, it is shown that current TF staining protocols do not destroy fluorescent proteins (FPs) but rather that fixation is not sufficient to retain FPs in the cytosol of the permeabilized cells. In this article, a simple and reliable protocol is elaborated, which allows efficient TF and cytokine staining while retaining FPs inside fixed cells.
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http://dx.doi.org/10.1002/cyto.a.22451DOI Listing
July 2014

Inflammatory demyelination induces glia alterations and ganglion cell loss in the retina of an experimental autoimmune encephalomyelitis model.

J Neuroinflammation 2013 Oct 4;10:120. Epub 2013 Oct 4.

Experimental Eye Research Institute, Ruhr University Eye Hospital, In der Schornau 23-25, 44892 Bochum, Germany.

Background: Multiple sclerosis (MS) is often accompanied by optic nerve inflammation. And some patients experience permanent vision loss. We examined if the grade of optic nerve infiltration and demyelination affects the severity of clinical signs in an experimental autoimmune encephalomyelitis (EAE) model. The loss of retinal ganglion cells (RGC) and alterations in glia activity were also investigated.

Methods: C57BL/6 mice were immunized with peptide MOG35-55 in complete Freund's adjuvant (CFA) and controls received PBS in CFA. Then 23 days post immunization eyes were prepared for flatmounts and stained with Nissl to evaluated neuronal density. Clinical EAE symptoms as well as cell infiltration and demyelination in the optic nerve were examined. Retinal sections were stained with hematoxylin and eosin and silver stain. Immunohistochemistry was used to label RGCs (Brn-3a), apoptotic cells (caspase 3), macroglia (glial fibrillary acidic protein (GFAP)), microglia (Iba1), macrophages (F 4/80) and interleukin-6 (IL-6) secretion.

Results: EAE symptoms started at day 8 and peaked at day 15. Cell infiltrations (P = 0.0047) and demyelination (P = 0.0018) of EAE nerves correlated with the clinical score (r > 0.8). EAE led to a significant loss of RGCs (P< 0.0001). Significantly more caspase 3+ cells were noted in these animals (P = 0.0222). They showed an increased expression of GFAP (P< 0.0002) and a higher number of microglial cells (P< 0.0001). Also more macrophages and IL-6 secretion were observed in EAE mice.

Conclusions: MOG immunization leads to optic neuritis and RGC loss. EAE severity is related to the severity of optic nerve inflammation and demyelination. EAE not only affects activation of apoptotic signals, but also causes a glial response in the retina.
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http://dx.doi.org/10.1186/1742-2094-10-120DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3851328PMC
October 2013

IL-6 regulates neutrophil microabscess formation in IL-17A-driven psoriasiform lesions.

J Invest Dermatol 2014 Mar 25;134(3):728-735. Epub 2013 Sep 25.

Institute for Molecular Medicine, University Medical Center of the Johannes-Gutenberg University of Mainz, Mainz, Germany. Electronic address:

The lack of a generally accepted animal model for human psoriasis has hindered progress with respect to understanding the pathogenesis of the disease. Here we present a model in which transgenic IL-17A expression is targeted to the skin in mice, achievable after crossing our IL-17A(ind) allele to the K14-Cre strain. K14-IL-17A(ind/+) mice invariably develop an overt skin inflammation bearing many hallmark characteristics of human psoriasis including dermal infiltration of effector T cells, formation of neutrophil microabscesses, and hyperkeratosis. IL-17A expression in the skin results in upregulated granulopoiesis and migration of IL-6R-expressing neutrophils into the skin. Neutralization of IL-6 signaling efficiently reduces the observed pathogenesis in skin of IL-17A-overexpressing mice, with marked reductions in epidermal neutrophil abscess formation and epidermal thickening. Thus, IL-6 functions downstream of IL-17A to exacerbate neutrophil microabscess development in psoriasiform lesions.
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http://dx.doi.org/10.1038/jid.2013.404DOI Listing
March 2014

Subclinical CNS inflammation as response to a myelin antigen in humanized mice.

J Neuroimmune Pharmacol 2013 Sep 3;8(4):1037-47. Epub 2013 May 3.

Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg-University Mainz, Obere Zahlbacher Straße 67, 55131 Mainz, Germany.

Multiple sclerosis is a demyelinating autoimmune disease of the CNS. Its animal model experimental autoimmune encephalomyelitis is commonly induced by active immunization with myelin antigens. To investigate human immune responses against myelin antigens in vivo we established a new subclinical experimental autoimmune encephalomyelitis model in humanized mice. NOD/Scidγc⁻/⁻ animals were transferred with peripheral blood mononuclear cells from healthy human donors and immunized with myelin antigens in complete Freund's adjuvant and antigen-pulsed autologous dendritic cells. Human T cells recovered from these animals reacted specifically to the soluble domain of myelin oligodendrocyte glycoprotein and secreted proinflammatory cytokines. Furthermore, immunized animals developed subclinical CNS inflammation with infiltrating CD4⁺ and CD8⁺ T cells and production of encephalitogenic cytokines. Thus, this model of myelin-induced CNS inflammation by human T cells may allow testing of new human-specific therapeuticals for multiple sclerosis.
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http://dx.doi.org/10.1007/s11481-013-9466-4DOI Listing
September 2013

TLR-4 ligation of dendritic cells is sufficient to drive pathogenic T cell function in experimental autoimmune encephalomyelitis.

J Neuroinflammation 2012 Oct 30;9:248. Epub 2012 Oct 30.

Medical Research Council/University of Edinburgh Centre for Inflammation Research, Centre for Multiple Sclerosis Research and Centre for Immunity Infection and Evolution, Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK.

Background: Experimental autoimmune encephalomyelitis (EAE) depends on the initial activation of CD4(+) T cells responsive to myelin autoantigens. The key antigen presenting cell (APC) population that drives the activation of naïve T cells most efficiently is the dendritic cell (DC). As such, we should be able to trigger EAE by transfer of DC that can present the relevant autoantigen(s). Despite some sporadic reports, however, models of DC-driven EAE have not been widely adopted. We sought to test the feasibility of this approach and whether activation of the DC by toll-like receptor (TLR)-4 ligation was a sufficient stimulus to drive EAE.

Findings: Host mice were seeded with myelin basic protein (MBP)-reactive CD4+ T cells and then were injected with DC that could present the relevant MBP peptide which had been exposed to lipopolysaccharide as a TLR-4 agonist. We found that this approach induced robust clinical signs of EAE.

Conclusions: DC are sufficient as APC to effectively drive the differentiation of naïve myelin-responsive T cells into autoaggressive effector T cells. TLR-4-stimulation can activate the DC sufficiently to deliver the signals required to drive the pathogenic function of the T cell. These models will allow the dissection of the molecular requirements of the initial DC-T cell interaction in the lymphoid organs that ultimately leads to autoimmune pathology in the central nervous system.
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http://dx.doi.org/10.1186/1742-2094-9-248DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3520704PMC
October 2012

An alternative pathway of imiquimod-induced psoriasis-like skin inflammation in the absence of interleukin-17 receptor a signaling.

J Invest Dermatol 2013 Feb 6;133(2):441-51. Epub 2012 Sep 6.

Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany.

Topical application of imiquimod (IMQ) on the skin of mice induces inflammation with common features found in psoriatic skin. Recently, it was postulated that IL-17 has an important role both in psoriasis and in the IMQ model. To further investigate the impact of IL-17RA signaling in psoriasis, we generated IL-17 receptor A (IL-17RA)-deficient mice (IL-17RA(del)) and challenged these mice with IMQ. Interestingly, the disease was only partially reduced and delayed but not abolished when compared with controls. In the absence of IL-17RA, we found persisting signs of inflammation such as neutrophil and macrophage infiltration within the skin. Surprisingly, already in the naive state, the skin of IL-17RA(del) mice contained significantly elevated numbers of Th17- and IL-17-producing γδ T cells, assuming that IL-17RA signaling regulates the population size of Th17 and γδ T cells. Upon IMQ treatment of IL-17RA(del) mice, these cells secreted elevated amounts of tumor necrosis factor-α, IL-6, and IL-22, accompanied by increased levels of the chemokine CXCL2, suggesting an alternative pathway of neutrophil and macrophage skin infiltration. Hence, our findings have major implications in the potential long-term treatment of psoriasis by IL-17-targeting drugs.
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http://dx.doi.org/10.1038/jid.2012.318DOI Listing
February 2013

Dendritic cells ameliorate autoimmunity in the CNS by controlling the homeostasis of PD-1 receptor(+) regulatory T cells.

Immunity 2012 Aug 16;37(2):264-75. Epub 2012 Aug 16.

Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg University, 55131 Mainz, Germany.

Mature dendritic cells (DCs) are established as unrivaled antigen-presenting cells (APCs) in the initiation of immune responses, whereas steady-state DCs induce peripheral T cell tolerance. Using various genetic approaches, we depleted CD11c(+) DCs in mice and induced autoimmune CNS inflammation. Unexpectedly, mice lacking DCs developed aggravated disease compared to control mice. Furthermore, when we engineered DCs to present a CNS-associated autoantigen in an induced manner, we found robust tolerance that prevented disease, which coincided with an upregulation of the PD-1 receptor on antigen-specific T cells. Additionally, we showed that PD-1 was necessary for DC-mediated induction of regulatory T cells. Our results show that a reduction of DCs interferes with tolerance, resulting in a stronger inflammatory response, and that other APC populations could compensate for the loss of immunogenic APC function in DC-depleted mice.
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http://dx.doi.org/10.1016/j.immuni.2012.05.025DOI Listing
August 2012

Modeling a complex disease: multiple sclerosis.

Adv Immunol 2011 ;110:111-37

Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg University, Mainz, Germany.

The recent decades have shown that multiple sclerosis (MS) is not a uniform disease entity with common etiology, but rather a disease or syndrome characterized by a heterogeneous pattern of manifestations and pathological principles. Apart from the older distinctions of the Devic's disease from the standard Western form of relapsing remitting MS or the more Asian form of opticospinal MS, specific pathological patterns indicating distinct etiologies have been established by analyses of biopsies and autopsies. Further, the distinct responses of patients to drugs targeting either specific cell types or immunoregulatory mechanisms such as Rituximab or IFNβ clearly demonstrate the heterogeneity of the disease and their driving mechanisms. Finally, the late neurodegenerative phase, which severe cases of MS patients experience, is now in the focus of research. Here, a mechanism independent of or with low participation of the adaptive immune system takes place, which is therefore not treatable by current immunotargeting drugs. In this review, we will summarize previous and latest efforts to establish new mouse models mirroring these distinct disease patterns and pathways.
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http://dx.doi.org/10.1016/B978-0-12-387663-8.00001-6DOI Listing
November 2011