The major therapeutic goal for immune thrombocytopenia (ITP) is to restore normal platelet counts using drugs to promote platelet production or by interfering with mechanisms responsible for platelet destruction. 80% of patients possess anti-integrin αIIbβ3 (GPIIbIIIa) IgG autoantibodies causing platelet opsonization and phagocytosis. The spleen is considered the primary site of autoantibody production by autoreactive B cells and platelet destruction. The immediate failure in ~50% of patients to recover a normal platelet count after anti-CD20 Rituximab-mediated B cell depletion and splenectomy suggest that autoreactive, rituximab-resistant, IgG-secreting B cells (IgG-SC) reside in other anatomical compartments. We analyzed >3,300 single IgG-SC from spleen, bone marrow and/or blood of 27 patients with ITP revealing high inter-individual variability in affinity for GPIIbIIIa with variations over 3 logs. IgG-SC dissemination and range of affinities were however similar per patient. Longitudinal analysis of autoreactive IgG-SC upon treatment with anti-CD38 mAb daratumumab demonstrated variable outcomes, from complete remission to failure with persistence of high-affinity anti-GPIIbIIIa IgG-SC in the bone marrow. This study demonstrates the existence and dissemination of high-affinity autoreactive plasma cells in multiple anatomical compartments of patients with ITP that may cause the failure of current therapies.
Pablo Canales-Herrerias, Etienne Crickx, Matteo Broketa, Aurélien Sokal, Guilhem Chenon, Imane Azzaoui, Alexis Vandenberghe, Angga Perima, Bruno Iannascoli, Odile Richard-Le Goff, Carlos Castrillon, Guillaume Mottet, Delphine Sterlin, Ailsa Robbins, Marc Michel, Patrick England, Gael A. Millot, Klaus Eyer, Jean Baudry, Matthieu Mahevas, Pierre Bruhns
The trace element iron affects immune responses and vaccination, but knowledge of its role in autoimmune diseases is limited. Expansion of pathogenic T cells, especially T follicular helper (Tfh) cells, has great significance to systemic lupus erythematosus (SLE) pathogenesis. Here, we show an important role of iron in regulation of pathogenic T cell differentiation in SLE. We found that iron overload promoted Tfh cell expansion, proinflammatory cytokine secretion, and autoantibody production in lupus-prone mice. Mice treated with a high-iron diet exhibited an increased proportion of Tfh cell and antigen-specific GC response. Iron supplementation contributed to Tfh cell differentiation. In contrast, iron chelation inhibited Tfh cell differentiation. We demonstrated that the miR-21/BDH2 axis drove iron accumulation during Tfh cell differentiation and further promoted Fe2+-dependent TET enzyme activity and BCL6 gene demethylation. Thus, maintaining iron homeostasis might be critical for eliminating pathogenic Th cells and might help improve the management of patients with SLE.
Xiaofei Gao, Yang Song, Jiali Wu, Shuang Lu, Xiaoli Min, Limin Liu, Longyuan Hu, Meiling Zheng, Pei Du, Yaqin Yu, Hai Long, Haijing Wu, Sujie Jia, Di Yu, Qianjin Lu, Ming Zhao
Rheumatoid arthritis (RA) is characterized by chronic synovial inflammation with aberrant epigenetic alterations, eventually leading to joint destruction. However, the epigenetic regulatory mechanisms underlying RA pathogenesis remain largely unknown. Here we showed that Ubiquitin-like containing PHD and RING finger domains 1 (UHRF1) is a central epigenetic regulator that suppressively orchestrates multiple pathogeneses in RA. UHRF1 expression was remarkably up-regulated in synovial fibroblasts (SF) from arthritis model mice and RA patients. Mice with SF-specific Uhrf1 conditional knockout showed more severe arthritic phenotypes than littermate control. Uhrf1-deficient SF also exhibited enhanced apoptosis resistance and up-regulated expression of several cytokines including Ccl20. In RA patients, DAS28, CRP, and Th17 accumulation as well as apoptosis resistance were negatively correlated with UHRF1 expression in synovium. Finally, Ryuvidine administration that stabilizes UHRF1 ameliorated arthritis pathogeneses in a mouse model of RA. This study demonstrated that UHRF1 expressed in RA SF can contribute to negative feedback mechanisms that suppress multiple pathogenic events in arthritis, suggesting that targeting UHRF1 could be one of the therapeutic strategies for RA.
Noritaka Saeki, Kazuki Inoue, Maky Ideta-Otsuka, Kunihiko Watamori, Shinichi Mizuki, Katsuto Takenaka, Katsuhide Igarashi, Hiromasa Miura, Shu Takeda, Yuuki Imai
CD13, an ectoenzyme on myeloid and stromal cells, also circulates as a shed, soluble protein (sCD13) with powerful chemoattractant, angiogenic and arthritogenic properties, which require engagement of a G protein-coupled receptor (GPCR). Here we identify the GPCR that mediates sCD13 arthritogenic actions as the bradykinin receptor B1 (B1R). Immunofluorescence and immunoblotting verified high expression of B1R in rheumatoid arthritis (RA) synovial tissue and synovial cell (FLS) lines, and demonstrated binding of sCD13 to B1R. Chemotaxis, and phosphorylation of Erk1/2, induced by sCD13, were inhibited by B1R antagonists. In ex vivo RA synovial tissue organ cultures, a B1R antagonist reduced secretion of inflammatory cytokines. Several mouse arthritis models, including serum-transfer, antigen-induced, and local innate immune stimulation arthritis models, were attenuated in Cd13-/- and B1R-/- mice and were alleviated by B1R antagonism. These results establish a CD13/B1R axis in the pathogenesis of inflammatory arthritis and identify B1R as a compelling novel therapeutic target in RA and potentially other inflammatory diseases.
Pei-Suen Tsou, Chenyang Lu, Mikel Gurrea-Rubio, Sei Muraoka, Phillip L. Campbell, Qi Wu, Ellen N. Model, Matthew E. Lind, Sirapa Vichaikul, Megan N. Mattichak, William D. Brodie, Jonatan L. Hervoso, Sarah Ory, Camila I. Amarista, Rida Pervez, Lucas Junginger, Mustafa Ali, Gal Hodish, Morgan M. O'Mara, Jeffrey H. Ruth, Aaron M. Robida, Andrew J. Alt, Chengxin Zhang, Andrew G. Urquhart, Jeffrey N. Lawton, Kevin C. Chung, Tristan Maerz, Thomas L. Saunders, Vincent E. Groppi, David A. Fox, Mohammad A. Amin
Dysregulation of Toll-like receptor (TLR) signaling contributes to the pathogenesis of autoimmune diseases. Here, we provide genetic evidence that tankyrase, a member of the poly(ADP-ribose) polymerase (PARP) family, negatively regulates TLR2 signaling. We show that mice lacking tankyrase in myeloid cells developed severe systemic inflammation with high serum inflammatory cytokine levels. We provide mechanistic evidence that tankyrase deficiency resulted in tyrosine phosphorylation and activation of TLR2 and show that phosphorylation of tyrosine 647 within the TIR domain by SRC and SYK kinases was critical for TLR2 stabilization and signaling. Last, we show that the elevated cytokine production and inflammation observed in mice lacking tankyrase in myeloid cells were dependent on the adaptor protein 3BP2, which is required for SRC and SYK activation. These data demonstrate that tankyrase provides a checkpoint on the TLR-mediated innate immune response.
Yoshinori Matsumoto, Ioannis D. Dimitriou, Jose La Rose, Melissa Lim, Susan Camilleri, Napoleon Law, Hibret A. Adissu, Jiefei Tong, Michael F. Moran, Andrzej Chruscinski, Fang He, Yosuke Asano, Takayuki Katsuyama, Ken-ei Sada, Jun Wada, Robert Rottapel
A disequilibrium between immunosuppressive regulatory T cells (Tregs) and inflammatory interleukin (IL)-17-producing Th17 cells is a hallmark of autoimmune diseases, including multiple sclerosis (MS). However, the molecular mechanisms underlying Treg and Th17 imbalance in central nervous system (CNS) autoimmunity remain largely unclear. Identifying factors which drive this imbalance is of high clinical interest. Here, we report a major disease-promoting role for microRNA-92a (miR-92a) in CNS autoimmunity. MiR-92a was elevated in experimental autoimmune encephalomyelitis (EAE), and its loss attenuated EAE. Mechanistically, miR-92a mediated EAE susceptibility in a T cell-intrinsic manner by restricting Treg induction and suppressive capacity, while supporting Th17 responses, by directly repressing the transcription factor, Foxo1. Although miR-92a did not directly alter Th1 differentiation, it appeared to indirectly promote Th1 cells by inhibiting Treg responses. Correspondingly, miR-92a inhibitor therapy ameliorated EAE by concomitantly boosting Treg cell responses and dampening inflammatory T cell responses. Analogous to mice, miR-92a was elevated in MS patient CD4+ T cells, and miR-92a silencing in patient T cells promoted Treg development whereas it limited Th17 differentiation. Together, our results demonstrate that miR-92a drives CNS autoimmunity by sustaining the Treg/Th17 imbalance and implicate miR-92a as a potential therapeutic target for MS.
Mai Fujiwara, Radhika Raheja, Lucien P. Garo, Amrendra K. Ajay, Ryoko Kadowaki-Saga, Sukrut H. Karandikar, Galina Gabriely, Rajesh Krishnan, Vanessa Beynon, Anu Paul, Amee Patel, Shrishti Saxena, Dan Hu, Brian C. Healy, Tanuja Chitnis, Roopali Gandhi, Howard L. Weiner, Gopal Murugaiyan
Targeted monoclonal antibody (mAb) therapies show great promise for the treatment of transplant rejection and autoimmune diseases by inducing more specific immunomodulatory effects than broadly immunosuppressive drugs routinely used. We recently described the therapeutic advantage of targeting CD45RC, expressed at high levels by conventional T cells (Tconv, CD45RChigh), their precursors and terminally differentiated T (TEMRA) cells, but not by regulatory T cells (Tregs, CD45RClow/-). We demonstrated efficacy of anti-CD45RC mAb treatment in transplantation but its potential has not been examined in autoimmune diseases. APECED is a rare genetic syndrome caused by loss-of-function mutations of the key central tolerance mediator, autoimmune regulator (AIRE) leading to abnormal auto-reactive T cell responses and autoantibodies production. Herein, we showed that, in a rat model of APECED syndrome, anti-CD45RC mAb was effective both as prevention and treatment of autoimmune manifestations and inhibited autoantibody development. Anti-CD45RC mAb intervention depleted CD45RChigh T cells, inhibited CD45RChigh B cells, and restored the Treg/Tconv ratio and the altered Tregs transcriptomic profile. In APECED patients, CD45RC was significantly increased in peripheral blood T cells and lesioned organs from APECED patients were infiltrated by CD45RChigh cells. Our observations highlight the potential role for CD45RChigh cells in the pathogenesis of experimental and human APECED syndrome and the potential of anti-CD45RC antibody treatment.
Marine Besnard, Céline Sérazin, Jason Ossart, Anne Moreau, Nadège Vimond, Léa Flippe, Hanna Sein, Grace A. Smith, Stefania Pittaluga, Elise M.N. Ferré, Claire Usal, Ignacio Anegon, Annamari Ranki, Michail S. Lionakis, Pärt Peterson, Carole Guillonneau
BMP6 is a central cytokine in the induction of Sjögren's syndrome (SS)-associated secretory hypofunction. However, the upstream initiation leading to the production of this cytokine in SS is unknown. In this study, RNA in situ hybridization on salivary gland sections taken from SS patients indicated monocytic lineage cells as a cellular source of BMP6. RNA sequencing data from human salivary glands suggested TLR4 signaling was an upstream regulator of BMP6, which was confirmed by in vitro cell assays and single-cell transcriptomics of human PBMCs. Further investigation showed HSP70 was an endogenous natural TLR4 ligand that stimulated BMP6 expression in SS. Release of HSP70 from epithelial cells could be triggered by overexpression of lysosome-associated membrane protein 3 (LAMP3), a protein also associated with SS in several transcriptome studies. In vitro studies supported HSP70 was released as a result of lysosomal exocytosis initiated by LAMP3 expression, and reverse transcription PCR on RNA from minor salivary glands of SS patients confirmed a positive correlation between BMP6 and LAMP3 expression. BMP6 expression could be experimentally induced in mice by overexpression of LAMP3, which developed an SS-like phenotype. The newly identified LAMP3/HSP70/BMP6 axis provided an etiological model for SS gland dysfunction and autoimmunity.
Ying-Qian Mo, Hiroyuki Nakamura, Tsutomu Tanaka, Toshio Odani, Paola Perez, Youngmi Ji, Benjamin N. French, Thomas J.F. Pranzatelli, Drew G. Michael, Hongen Yin, Susan S. Chow, Maryam Khalaj, Sandra A. Afione, Changyu Zheng, Fabiola Reis Oliveira, Ana Carolina F. Motta, Alfredo Ribeiro-Silva, Eduardo M. Rocha, Cuong Q. Nguyen, Masayuki Noguchi, Tatsuya Atsumi, Blake M. Warner, John A. Chiorini
Inborn errors of nucleic acid metabolism often cause aberrant activation of nucleic acid sensing pathways, leading to autoimmune or autoinflammatory diseases. The SKIV2L RNA exosome is cytoplasmic RNA degradation machinery that was thought to be essential for preventing the self-RNA–mediated interferon (IFN) response. Here, we demonstrate the physiological function of SKIV2L in mammals. We found that Skiv2l deficiency in mice disrupted epidermal and T cell homeostasis in a cell-intrinsic manner independently of IFN. Skiv2l-deficient mice developed skin inflammation and hair abnormality, which were also observed in a SKIV2L-deficient patient. Epidermis-specific deletion of Skiv2l caused hyperproliferation of keratinocytes and disrupted epidermal stratification, leading to impaired skin barrier with no appreciable IFN activation. Moreover, Skiv2l-deficient T cells were chronically hyperactivated and these T cells attacked lesional skin as well as hair follicles. Mechanistically, SKIV2L loss activated the mTORC1 pathway in both keratinocytes and T cells. Both systemic and topical rapamycin treatment of Skiv2l-deficient mice ameliorated epidermal hyperplasia and skin inflammation. Together, we demonstrate that mTORC1, a classical nutrient sensor, also senses cytoplasmic RNA quality control failure and drives autoinflammatory disease. We also propose SKIV2L-associated trichohepatoenteric syndrome (THES) as a new mTORopathy for which sirolimus may be a promising therapy.
Kun Yang, Jie Han, Mayumi Asada, Jennifer G. Gill, Jason Y. Park, Meghana N. Sathe, Jyothsna Gattineni, Tracey Wright, Christian A. Wysocki, M. Teresa de la Morena, Luis A. Garza, Nan Yan
BACKGROUND The temporal clustering of a cancer diagnosis with dermatomyositis (DM) onset is strikingly associated with autoantibodies against transcriptional intermediary factor 1-γ (TIF1-γ). Nevertheless, many patients with anti–TIF1-γ antibodies never develop cancer. We investigated whether additional autoantibodies are found in anti–TIF1-γ–positive patients without cancer.METHODS Using a proteomic approach, we defined 10 previously undescribed autoantibody specificities in 5 index anti–TIF1-γ–positive DM patients without cancer. These were subsequently examined in discovery (n = 110) and validation (n = 142) cohorts of DM patients with anti–TIF1-γ autoantibodies.RESULTS We identified 10 potentially novel autoantibodies in anti–TIF1-γ–positive DM patients, 6 with frequencies ranging from 3% to 32% in 2 independent DM cohorts. Autoantibodies recognizing cell division cycle and apoptosis regulator protein 1 (CCAR1) were the most frequent, and were significantly negatively associated with contemporaneous cancer (discovery cohort OR 0.27 [95% CI 0.7–1.00], P = 0.050; validation cohort OR 0.13 [95% CI 0.03–0.59], P = 0.008). When cancer did emerge, it occurred significantly later in anti-CCAR1–positive compared with anti-CCAR1–negative patients (median time from DM onset 4.3 vs. 0.85 years, respectively; P = 0.006). Cancers that emerged were more likely to be localized (89% of anti-CCAR1–positive cancers presenting at stage 0 or 1 compared with 42% of patients without anti-CCAR1 antibodies, P = 0.02). As the number of additional autoantibody specificities increased in anti–TIF1-γ–positive DM patients, the frequency of cancer decreased (P < 0.001).CONCLUSION As the diversity of immune responses in anti–TIF1-γ DM patients increases, the likelihood of cancer emerging decreases. Our findings have important relevance for cancer risk stratification in DM patients and for understanding natural immune regulation of cancer in humans.TRIAL REGISTRATION Not applicable.FUNDING SOURCES The NIH, the Donald B. and Dorothy L. Stabler Foundation, and the Huayi and Siuling Zhang Discovery Fund.
David F. Fiorentino, Christopher A. Mecoli, Matthew C. Rosen, Lorinda S. Chung, Lisa Christopher-Stine, Antony Rosen, Livia Casciola-Rosen
No posts were found with this tag.