Autoimmunity
Abstract
Chronic inflammatory demyelinating polyneuropathy (CIDP) and Guillain-Barre syndrome (GBS) are inflammatory neuropathies that affect humans and are characterized by peripheral nerve myelin destruction and macrophage-containing immune infiltrates. In contrast to the traditional view that the peripheral nerve is simply the target of autoimmunity, we report here that peripheral nerve Schwann cells exacerbate the autoimmune process through extracellular matrix (ECM) protein induction. In a spontaneous autoimmune peripheral polyneuropathy (SAPP) mouse model of inflammatory neuropathy and CIDP nerve biopsies, the ECM protein periostin (POSTN) was upregulated in affected sciatic nerves and was primarily expressed by Schwann cells. Postn deficiency delayed the onset and reduced the extent of neuropathy, as well as decreased the number of macrophages infiltrating the sciatic nerve. In an in vitro assay, POSTN promoted macrophage chemotaxis in an integrin-AM (ITGAM) and ITGAV-dependent manner. The PNS-infiltrating macrophages in SAPP-affected nerves were pathogenic, since depletion of macrophages protected against the development of neuropathy. Our findings show that Schwann cells promote macrophage infiltration by upregulating Postn and suggest that POSTN is a novel target for the treatment of macrophage-associated inflammatory neuropathies.
Authors
Denise E. Allard, Yan Wang, Jian Joel Li, Bridget Conley, Erin W. Xu, David Sailer, Caellaigh Kimpston, Rebecca Notini, Collin-Jamal Smith, Emel Koseoglu, Joshua Starmer, Xiaopei L. Zeng, James F. Howard Jr., Ahmet Hoke, Steven S. Scherer, Maureen A. Su
Abstract
While T cells are important for the pathogenesis of systemic lupus erythematosus (SLE) and lupus nephritis, little is known about how T cells function after infiltrating the kidney. The current paradigm suggests that kidney infiltrating T cells (KITs) are activated effector cells contributing to tissue damage and ultimately organ failure. Herein, we demonstrate that the majority of CD4+ and CD8+ KITs in three murine lupus models are not effector cells, as hypothesized, but rather expressed multiple inhibitory receptors and proved highly dysfunctional with reduced cytokine production and proliferative capacity. Mechanistically this was linked directly to metabolic and specifically mitochondrial dysfunction. This was driven by the expression of an “exhausted” transcriptional signature. Our data thus reveal that the tissue parenchyma has the capability to suppress T cell responses and limit damage to self. These findings open novel avenues for the treatment of autoimmunity based on selectively exploiting the exhausted phenotype of tissue-infiltrating T cells.
Authors
Jeremy S. Tilstra, Lyndsay Avery, Ashley V. Menk, Rachael A. Gordon, Shuchi Smita, Lawrence P. Kane, Maria Chikina, Greg M. Delgoffe, Mark J. Shlomchik
Abstract
SUMOylation is involved in the development of several inflammatory diseases, but the physiological significance of SUMO-modulated c-Maf in autoimmune diabetes is not completely understood. Here, we report that an age-dependent attenuation of c-Maf SUMOylation in CD4+ T cells is positively correlated with the IL-21–mediated diabetogenesis in NOD mice. Using 2 strains of T cell–specific transgenic NOD mice overexpressing wild-type c-Maf (Tg-WTc) or SUMOylation site–mutated c-Maf (Tg-KRc), we demonstrated that Tg-KRc mice developed diabetes more rapidly than Tg-WTc mice in a CD4+ T cell–autonomous manner. Moreover, SUMO-defective c-Maf preferentially transactivated Il21 to promote the development of CD4+ T cells with an extrafollicular helper T cell phenotype and expand the numbers of granzyme B–producing effector/memory CD8+ T cells. Furthermore, SUMO-defective c-Maf selectively inhibited recruitment of Daxx/HDAC2 to the Il21 promoter and enhanced histone acetylation mediated by CREB-binding protein (CBP) and p300. Using pharmacological interference with CBP/p300, we illustrated that CBP30 treatment ameliorated c-Maf–mediated/IL-21–based diabetogenesis. Taken together, our results show that the SUMOylation status of c-Maf has a stronger regulatory effect on IL-21 than the level of c-Maf expression, through an epigenetic mechanism. These findings provide new insights into how SUMOylation modulates the pathogenesis of autoimmune diabetes in a T cell–restricted manner and on the basis of a single transcription factor.
Authors
Chao-Yuan Hsu, Li-Tzu Yeh, Shin-Huei Fu, Ming-Wei Chien, Yu-Wen Liu, Shi-Chuen Miaw, Deh-Ming Chang, Huey-Kang Sytwu
Abstract
BACKGROUND. Intravenous immunoglobulin (IVIg), plasma exchange and immunoadsorption are frequently used in the management of severe autoimmune diseases mediated by pathogenic IgG autoantibodies. These approaches to modulate IgG levels can however be associated with some severe adverse reactions and significant burden to patients. Targeting the neonatal Fc receptor (FcRn) presents an innovative and potentially more effective, safer, and convenient alternative for clearing pathogenic IgGs. METHODS. A randomized, double-blind, placebo-controlled first-in-human study was conducted in 62 healthy volunteers to explore single and multiple ascending intravenous doses of the FcRn antagonist efgartigimod. The study objectives were to assess the safety, tolerability, pharmacokinetics, pharmacodynamics, and immunogenicity. The findings of this study were compared with the pharmacodynamics profile elicited by efgartigimod in cynomolgus monkeys. RESULTS. Efgartigimod treatment resulted in a rapid and specific clearance of serum IgG levels in both cynomolgus monkeys and healthy volunteers. In humans, single administration of efgartigimod reduced IgG levels up to 50% whilst multiple dosing further lowered IgGs on average by 75% of baseline levels. Approximately 8 weeks following the last administration, IgG levels returned to baseline. Efgartigimod did not alter the homeostasis of albumin or immunoglobulins other than IgG and no serious adverse events related to efgartigimod infusion were observed. CONCLUSION. Antagonizing FcRn using efgartigimod is safe and results in a specific, profound, and sustained reduction of serum IgG levels. These results warrant further evaluation of this therapeutic approach in IgG-driven autoimmune diseases. TRIAL REGISTRATION. Clinicaltrials.gov NCT03457649. FUNDING. argenx bvba.
Authors
Peter Ulrichts, Antonio Guglietta, Torsten Dreier, Tonke van Bragt, Valérie Hanssens, Erik Hofman, Bernhardt Vankerckhoven, Peter Verheesen, Nicolas Ongenae, Valentina Lykhopiy, F. Javier Enriquez, JunHaeng Cho, Raimund J. Ober, E. Sally Ward, Hans de Haard, Nicolas Leupin
Abstract
Podocyte malfunction occurs in autoimmune and nonautoimmune kidney disease. Calcium signaling is essential for podocyte injury, but the role of Ca2+/calmodulin–dependent kinase (CaMK) signaling in podocytes has not been fully explored. We report that podocytes from patients with lupus nephritis and focal segmental glomerulosclerosis and lupus-prone and lipopolysaccharide- or adriamycin-treated mice display increased expression of CaMK IV (CaMK4), but not CaMK2. Mechanistically, CaMK4 modulated podocyte motility by altering the expression of the GTPases Rac1 and RhoA and suppressed the expression of nephrin, synaptopodin, and actin fibers in podocytes. In addition, it phosphorylated the scaffold protein 14-3-3β, which resulted in the release and degradation of synaptopodin. Targeted delivery of a CaMK4 inhibitor to podocytes preserved their ultrastructure, averted immune complex deposition and crescent formation, and suppressed proteinuria in lupus-prone mice and proteinuria in mice exposed to lipopolysaccharide-induced podocyte injury by preserving nephrin/synaptopodin expression. In animals exposed to adriamycin, podocyte-specific delivery of a CaMK4 inhibitor prevented and reversed podocyte injury and renal disease. We conclude that CaMK4 is pivotal in immune and nonimmune podocyte injury and that its targeted cell-specific inhibition preserves podocyte structure and function and should have therapeutic value in lupus nephritis and podocytopathies, including focal segmental glomerulosclerosis.
Authors
Kayaho Maeda, Kotaro Otomo, Nobuya Yoshida, Mones S. Abu-Asab, Kunihiro Ichinose, Tomoya Nishino, Michihito Kono, Andrew Ferretti, Rhea Bhargava, Shoichi Maruyama, Sean Bickerton, Tarek M. Fahmy, Maria G. Tsokos, George C. Tsokos
Abstract
Toll-like receptors TLR7 and TLR9 are both implicated in the activation of autoreactive B cells and other cell types associated with systemic lupus erythematosus (SLE) pathogenesis. However, Tlr9–/– autoimmune-prone strains paradoxically develop more severe disease. We have now leveraged the negative regulatory role of TLR9 to develop an inducible rapid-onset murine model of systemic autoimmunity that depends on T cell detection of a membrane-bound OVA fusion protein expressed by MHC class II+ cells, expression of TLR7, expression of the type I IFN receptor, and loss of expression of TLR9. These mice are distinguished by a high frequency of OVA-specific Tbet+, IFN-γ+, and FasL-expressing Th1 cells as well as autoantibody-producing B cells. Unexpectedly, contrary to what occurs in most models of SLE, they also developed skin lesions that are very similar to those of human cutaneous lupus erythematosus (CLE) as far as clinical appearance, histological changes, and gene expression. FasL was a key effector mechanism in the skin, as the transfer of FasL-deficient DO11gld T cells completely failed to elicit overt skin lesions. FasL was also upregulated in human CLE biopsies. Overall, our model provides a relevant system for exploring the pathophysiology of CLE as well as the negative regulatory role of TLR9.
Authors
Purvi Mande, Bahar Zirak, Wei-Che Ko, Keyon Taravati, Karen L. Bride, Tia Y. Brodeur, April Deng, Karen Dresser, Zhaozhao Jiang, Rachel Ettinger, Katherine A. Fitzgerald, Michael D. Rosenblum, John E. Harris, Ann Marshak-Rothstein
Abstract
In type 1 diabetes, cytotoxic CD8 T cells with specificity for β-cell autoantigens are found in the pancreatic islets where they are implicated in the destruction of insulin-secreting β cells. In contrast, the disease relevance of β-cell-reactive CD8 T cells that are detectable in the circulation, and their relationship to β-cell function, are not known. Here, we tracked multiple, circulating β-cell-reactive CD8 T cell subsets and measured β-cell function longitudinally for two years, starting immediately after diagnosis of type 1 diabetes. We found that change in β-cell-specific effector memory CD8 T cells expressing CD57 was positively correlated with C-peptide change in subjects below 12 years of age. Autoreactive CD57+ effector memory CD8 T cells bore the signature of enhanced effector function (higher expression of granzyme B, killer specific protein 37 and CD16, and reduced expression of CD28) compared with their CD57-negative counterparts, and network association modelling indicated that the dynamics of β-cell-reactive CD57+ effector memory CD8 T cell subsets were strongly linked. Thus, coordinated changes in circulating β-cell-specific CD8 T cells within the CD57+ effector memory subset calibrate to functional insulin reserve in type 1 diabetes, providing a tool for immune monitoring and a mechanism-based target for immunotherapy.
Authors
Lorraine Yeo, Alyssa Woodwyk, Sanjana Sood, Anna Lorenc, Martin Eichmann, Irma Pujol-Autonell, Rossella Melchiotti, Ania Skowera, Efthymios Fidanis, Garry M. Dolton, Katie Tungatt, Andrew K. Sewell, Susanne Heck, Alka Saxena, Craig A. Beam, Mark Peakman
Abstract
Immune imbalance of T lymphocyte subsets is a hallmark of psoriasis, but the molecular mechanisms underlying this aspect of psoriasis pathology are poorly understood. Here, we report that microRNA-210 (miR-210), a miR that is highly expressed in both psoriasis patients and mouse models, induces helper T (Th) 17 and Th1 cell differentiation but inhibits Th2 differentiation through repressing STAT6 and LYN expression, contributing to several aspects of the immune imbalance in psoriasis. Both miR-210 ablation in mice and inhibition of miR-210 by intradermal injection of antagomir-210 blocked the immune imbalance and the development of psoriasis-like inflammation in an imiquimod-induced or IL-23–induced psoriasis-like mouse model. We further showed that TGF-β and IL-23 enhance miR-210 expression by inducing HIF-1α, which recruits P300 and promotes histone H3 acetylation in the miR-210 promoter region. Our results reveal a crucial role for miR-210 in the immune imbalance of T lymphocyte subsets in psoriasis and suggest a potential therapeutic avenue.
Authors
Ruifang Wu, Jinrong Zeng, Jin Yuan, Xinjie Deng, Yi Huang, Lina Chen, Peng Zhang, Huan Feng, Zixin Liu, Zijun Wang, Xiaofei Gao, Haijing Wu, Honglin Wang, Yuwen Su, Ming Zhao, Qianjin Lu
Abstract
Little is known about the repertoire dynamics and persistence of pathogenic T cells in HLA-associated disorders. In celiac disease, a disorder with a strong association with certain HLA-DQ allotypes, presumed pathogenic T cells can be visualized and isolated with HLA-DQ:gluten tetramers, thereby enabling further characterization. Single and bulk populations of HLA-DQ:gluten tetramer–sorted CD4+ T cells were analyzed by high-throughput DNA sequencing of rearranged TCR-α and -β genes. Blood and gut biopsy samples from 21 celiac disease patients, taken at various stages of disease and in intervals of weeks to decades apart, were examined. Persistence of the same clonotypes was seen in both compartments over decades, with up to 53% overlap between samples obtained 16 to 28 years apart. Further, we observed that the recall response following oral gluten challenge was dominated by preexisting CD4+ T cell clonotypes. Public features were frequent among gluten-specific T cells, as 10% of TCR-α, TCR-β, or paired TCR-αβ amino acid sequences of total 1813 TCRs generated from 17 patients were observed in 2 or more patients. In established celiac disease, the T cell clonotypes that recognize gluten are persistent for decades, making up fixed repertoires that prevalently exhibit public features. These T cells represent an attractive therapeutic target.
Authors
Louise F. Risnes, Asbjørn Christophersen, Shiva Dahal-Koirala, Ralf S. Neumann, Geir K. Sandve, Vikas K. Sarna, Knut E.A. Lundin, Shuo-Wang Qiao, Ludvig M. Sollid
Abstract
Autoimmune diseases, such as psoriasis and arthritis, show a patchy distribution of inflammation despite systemic dysregulation of adaptive immunity. Thus, additional tissue-derived signals, such as danger-associated molecular patterns (DAMPs), are indispensable for manifestation of local inflammation. S100A8/S100A9 complexes are the most abundant DAMPs in many autoimmune diseases. However, regulatory mechanisms locally restricting DAMP activities are barely understood. We now unravel for the first time, to our knowledge, a mechanism of autoinhibition in mice and humans restricting S100-DAMP activity to local sites of inflammation. Combining protease degradation, pull-down assays, mass spectrometry, and targeted mutations, we identified specific peptide sequences within the second calcium-binding EF-hands triggering TLR4/MD2-dependent inflammation. These binding sites are free when S100A8/S100A9 heterodimers are released at sites of inflammation. Subsequently, S100A8/S100A9 activities are locally restricted by calcium-induced (S100A8/S100A9)2 tetramer formation hiding the TLR4/MD2-binding site within the tetramer interphase, thus preventing undesirable systemic effects. Loss of this autoinhibitory mechanism in vivo results in TNF-α–driven fatal inflammation, as shown by lack of tetramer formation in crossing S100A9–/– mice with 2 independent TNF-α–transgene mouse strains. Since S100A8/S100A9 is the most abundant DAMP in many inflammatory diseases, specifically blocking the TLR4-binding site of active S100 dimers may represent a promising approach for local suppression of inflammatory diseases, avoiding systemic side effects.
Authors
Thomas Vogl, Athanasios Stratis, Viktor Wixler, Tom Völler, Sumita Thurainayagam, Selina K. Jorch, Stefanie Zenker, Alena Dreiling, Deblina Chakraborty, Mareike Fröhling, Peter Paruzel, Corinna Wehmeyer, Sven Hermann, Olympia Papantonopoulou, Christiane Geyer, Karin Loser, Michael Schäfers, Stephan Ludwig, Monika Stoll, Tomas Leanderson, Joachim L. Schultze, Simone König, Thomas Pap, Johannes Roth
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ISSN: 0021-9738 (print), 1558-8238 (online)