U1RNP complex, Ro/SSA and La/SSB are major RNA-containing autoantigens. Immune complexes (ICs) composed of RNA-containing autoantigens and autoantibodies are suspected to be involved in the pathogenesis of some systemic autoimmune diseases. Therefore, RNase treatment, which degrades RNA in ICs, has been tested in clinical trials as a potential therapeutic agent. However, no studies have specifically evaluated the effect of RNase treatment on the Fcγ receptor-stimulatory activity of RNA-containing ICs. In this study, using a reporter system that specifically detects Fcγ receptor-stimulatory capacity, we investigated the effect of RNase treatment on the Fcγ receptor-stimulatory activity of RNA-containing ICs composed of autoantigens and autoantibodies from patients with systemic autoimmune diseases such as systemic lupus erythematosus. We found that RNase enhanced the Fcγ receptor-stimulatory activity of Ro/SSA- and La/SSB-containing ICs, but attenuated that of the U1RNP complex-containing ICs. RNase decreased autoantibody binding to the U1RNP complex, but increased autoantibody binding to Ro/SSA and La/SSB. Our results suggest that RNase enhances Fcγ receptor activation by promoting the formation of ICs containing Ro/SSA or La/SSB. Our study provides new insights into the pathophysiology of autoimmune diseases involving anti-Ro/SSA and anti-La/SSB autoantibodies, and into the therapeutic application of RNase treatment for systemic autoimmune diseases.
Ryota Naito, Koichiro Ohmura, Shuhei Higuchi, Wataru Nakai, Masako Kohyama, Tsuneyo Mimori, Akio Morinobu, Hisashi Arase
B cells contribute to multiple aspects of autoimmune disorders, and B cell–targeting therapies, including B cell depletion, have been proven to be efficacious in treatment of multiple autoimmune diseases. However, the development of novel therapies targeting B cells with higher efficacy and a nondepleting mechanism of action is highly desirable. Here we describe a nondepleting, high-affinity anti–human CD19 antibody LY3541860 that exhibits potent B cell inhibitory activities. LY3541860 inhibits B cell activation, proliferation, and differentiation of primary human B cells with high potency. LY3541860 also inhibits human B cell activities in vivo in humanized mice. Similarly, our potent anti-mCD19 antibody also demonstrates improved efficacy over CD20 B cell depletion therapy in multiple B cell–dependent autoimmune disease models. Our data indicate that anti-CD19 antibody is a highly potent B cell inhibitor that may have potential to demonstrate improved efficacy over currently available B cell–targeting therapies in treatment of autoimmune conditions without causing B cell depletion.
Jeffrey S. Boyles, Dorota Sadowski, Scott Potter, Aleksandra Vukojicic, James Parker, William Y. Chang, Yanfei L. Ma, Mark G. Chambers, James Nelson, Barbra Barmettler, Eric M. Smith, Kara Kersjes, Evan R. Himes, Chaohua Lin, Jonathan Lucchesi, Jaladhi Brahmbhatt, Ramtin Sina, Jennifer A. Martin, Evan Maestri, Christopher M. Wiethoff, Gregory L. Dyas, Matthew D. Linnik, Songqing Na, Derrick R. Witcher, Alison Budelsky, Kira Rubtsova
Neutrophil extracellular trap (NET) formation contributes to immune defense and is a distinct form of cell death. Excessive NET formation is found in patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), contributing to disease progression. The clearance of dead cells by macrophages, a process known as efferocytosis, is regulated by the CD47-mediated “don’t eat me” signal. Hence, we hypothesized that pathogenic NETs in AAV escape from efferocytosis via the CD47 signaling pathway, resulting in the development of necrotizing vasculitis. Immunostaining for CD47 in human renal tissues revealed high CD47 expression in crescentic glomerular lesions of patients with AAV. In ex vivo studies, ANCA-induced netting neutrophils increased the expression of CD47 with the reduction of efferocytosis. After efferocytosis, macrophages displayed pro-inflammatory phenotypes. The blockade of CD47 in spontaneous crescentic glomerulonephritis-forming/Kinjoh (SCG/Kj) mice ameliorated renal disease and reduced myeloperoxidase (MPO)-ANCA titers with a reduction in NETs formation. Thus, CD47 blockade would protect against developing glomerulonephritis in AAV via restored efferocytosis of ANCA-induced NETs.
Satoka Shiratori-Aso, Daigo Nakazawa, Takashi Kudo, Masatoshi Kanda, Yusho Ueda, Kanako Watanabe-Kusunoki, Saori Nishio, Sari Iwasaki, Takahiro Tsuji, Sakiko Masuda, Utano Tomaru, Akihiro Ishizu, Tatsuya Atsumi
Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disorder that causes debilitating swelling and destruction of the joints. People with RA are treated with drugs that actively suppress one or more parts of their immune system, and these may alter their response to vaccination against SARS-CoV-2. In this study, we analyzed blood samples from a cohort of RA subjects after receiving a 2-dose mRNA COVID-19 vaccine regimen. Our data show that individuals on the CTLA4-Ig therapy abatacept have reduced levels of SARS-CoV-2-neutralizing antibodies after vaccination. At a cellular level, these subjects show reduced activation and class-switching of SARS-CoV-2-specific B cells, as well as reduced numbers and impaired helper cytokine production by SARS-CoV-2-specific CD4+ T cells. Individuals on methotrexate showed similar but less severe defects in vaccine response, whereas individuals on the B cell-depleting therapy rituximab had a near-total loss of antibody production after vaccination. These data define a specific cellular phenotype associated with impaired response to SARS-CoV-2 vaccination in RA subjects on different immune-modifying therapies, and help inform efforts to improve vaccination strategies in this vulnerable population.
Samuel D Klebanoff, Lauren B. Rodda, Chihiro Morishima, Mark H. Wener, Yevgeniy Yuzefpolskiy, Estelle Bettelli, Jane H. Buckner, Cate Speake, Marion Pepper, Daniel J. Campbell
Multi-organ fibrosis in systemic sclerosis (SSc) accounts for substantial mortality and lacks effective therapies. Lying at the crossroad of transforming growth factor-β (TGF-β) and toll-like receptor (TLR) signaling, TGF-β-activated kinase 1 (TAK1) might have a pathogenic role in SSc. We therefore sought to evaluate the TAK1 signaling axis in patients with SSc, and investigate pharmacological TAK1 blockade using a novel drug-like selective TAK1 inhibitor, HS-276. Inhibiting TAK1 abrogated TGF-β1 stimulation of collagen synthesis and myofibroblasts differentiation in healthy skin fibroblasts, and ameliorated constitutive activation of SSc skin fibroblasts. Moreover, treatment with HS-276 prevented dermal and pulmonary fibrosis and reduced the expression of profibrotic mediators in bleomycin-treated mice. Importantly, initiating HS-276 treatment even after fibrosis was already established prevented its progression in affected organs. Together, these findings implicate TAK1 in the pathogenesis of SSc, and identify targeted TAK1 inhibition using a small molecule as a potential strategy for the treatment of SSc and other fibrotic diseases.
Swarna Bale, Priyanka Verma, Bharath Yalavarthi, Scott A. Scarneo, Philip F. Hughes, M. Asif Amin, Pei-Suen Tsou, Dinesh Khanna, Timothy A.J. Haystead, Swati Bhattacharyya, John Varga
Therapeutic strategies targeting complement have revolutionized the treatment of myasthenia gravis (MG). However, a deeper understanding of complement modulation in the human system is required to improve treatment responses and identify “off-target effects” shaping long-term outcomes. For this purpose, we studied a cohort of MG patients treated with either eculizumab (n = 10) or azathioprine (n = 10) as well as treatment-naïve (n = 10) patients using a combined proteomics and metabolomics approach. This strategy confirmed known effects of eculizumab on the terminal complement cascade. Beyond that, eculizumab modulated the serum proteometabolome as distinct pathways were altered in eculizumab-treated patients including the oxidative stress response, mitogen-activated protein kinase signaling and lipid metabolism with particular emphasis on arachidonic acid signaling. We detected reduced levels of arachidonate 5-lipoxygenase (ALOX5) and leukotriene A4 (LTA4) in eculizumab-treated patients. Mechanistically, ligation of the C5a receptor (C5aR) is needed for ALOX5 metabolism and generation of downstream leukotrienes. As eculizumab prevents cleavage of C5 into C5a, decreased engagement of C5aR may inhibit ALOX5-mediated synthesis of pro-inflammatory leukotrienes. These findings indicate distinct “off-target effects” induced by eculizumab, illuminating potential mechanisms of action that may be harnessed to improve treatment outcomes.
Christopher Nelke, Christina B. Schroeter, Frauke Stascheit, Niklas Huntemann, Marc Pawlitzki, Alice G. Willison, Saskia Räuber, Nico Melzer, Ute Distler, Stefan Tenzer, Kai Stühler, Andreas Roos, Andreas Meisel, Sven G. Meuth, Tobias Ruck
Methotrexate (MTX) is a standard, first-line therapy for rheumatoid arthritis (RA); however, its precise mechanisms of action other than antifolate activity are largely unknown. We performed DNA microarray analyses of CD4+ T cells in patients with RA before and after MTX treatment and found that TP63 was the most significantly downregulated gene after MTX treatment. TAp63, an isoform of TP63, was highly expressed in human IL-17–producing Th (Th17) cells and was suppressed by MTX in vitro. Murine TAp63 was expressed at high levels in Th cells and at lower levels in thymus-derived Treg cells. Importantly, TAp63 knockdown in murine Th17 cells ameliorated the adoptive transfer arthritis model. RNA-Seq analyses of human Th17 cells overexpressing TAp63 and those with TAp63 knockdown identified FOXP3 as a possible TAp63 target gene. TAp63 knockdown in CD4+ T cells cultured under Th17 conditions with low-dose IL-6 increased Foxp3 expression, suggesting that TAp63 balances Th17 cells and Treg cells. Mechanistically, TAp63 knockdown in murine induced Treg (iTreg) cells promoted hypomethylation of conserved noncoding sequence 2 (CNS2) of the Foxp3 gene and enhanced the suppressive function of iTreg cells. Reporter analyses revealed that TAp63 suppressed the activation of the Foxp3 CNS2 enhancer. Collectively, TAp63 suppresses Foxp3 expression and exacerbates autoimmune arthritis.
Kensuke Suga, Akira Suto, Shigeru Tanaka, Yutaka Sugawara, Takahiro Kageyama, Junichi Ishikawa, Yoshie Sanayama, Kei Ikeda, Shunsuke Furuta, Shin-Ichiro Kagami, Arifumi Iwata, Koichi Hirose, Kotaro Suzuki, Osamu Ohara, Hiroshi Nakajima
Myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD) is an inflammatory demyelinating central nervous system condition characterized by the presence of MOG autoantibodies. We sought to investigate whether human MOG autoantibodies are capable of mediating damage to MOG-expressing cells through multiple mechanisms. We developed high-throughput assays to measure complement activity (CA), complement-dependent cytotoxicity (CDC), antibody-dependent cellular phagocytosis (ADCP), and antibody-dependent cellular cytotoxicity (ADCC) of live MOG-expressing cells. MOGAD patient sera effectively mediate all of these effector functions. Our collective analyses reveal that [i] cytotoxicity is not incumbent on MOG autoantibody quantity alone, [ii] engagement of effector functions by MOGAD patient serum is bimodal, with some sera exhibiting cytotoxic capacity while others did not, [iii] the magnitude of CDC and ADCP is elevated closer to relapse, while MOG-IgG binding is not, and [iv] all IgG subclasses can damage MOG-expressing cells. Histopathology from a representative MOGAD case revealed congruence between lesion histology and serum CDC and ADCP, and we identified NK cells, mediators of ADCC, in the cerebrospinal fluid of relapsing MOGAD patients. Thus, MOGAD-derived autoantibodies are cytotoxic to MOG-expressing cells through multiple mechanisms and assays quantifying CDC and ADCP may prove to be effective tools for predicting risk of future relapses.
Soumya S. Yandamuri, Beata Filipek, Abeer H. Obaid, Nikhil Lele, Joshua M. Thurman, Naila Makhani, Richard J. Nowak, Yong Guo, Claudia F. Lucchinetti, Eoin P. Flanagan, Erin E. Longbrake, Kevin C. O'Connor
Abdominal aortic aneurysm (AAA) is usually asymptomatic until life-threatening complications occur, predominantly involving aortic rupture. Currently, no drug-based treatments are available, primarily due to limited understanding of AAA pathogenesis. Transcriptional regulator PR domain-containing protein 16 (PRDM16) is highly expressed in the aorta, but its functions in the aorta are largely unknown. By RNA-seq analysis, we found that VSMCs-specific Prdm16 knockout mice (Prdm16SMKO) already showed extensive changes in the expression of genes associated with extracellular matrix (ECM) remodeling and inflammation in the abdominal aorta under normal housing conditions without any pathological stimuli. Human AAA lesions displayed lower PRDM16 expression. Periadventitial elastase application to the suprarenal region of the abdominal aorta aggravated AAA formation in Prdm16SMKO. During AAA development, VSMCs undergo apoptosis because of both intrinsic and environmental changes including inflammation and ECM remodeling. Prdm16 deficiency promoted inflammation and apoptosis in VSMCs. A disintegrin and metalloproteinase 12 (ADAM12) is a gelatinase which can degrade various ECM. We found that ADAM12 is a target of transcriptional repression by PRDM16. Adam12 knockdown reversed VSMC apoptosis induced by Prdm16 deficiency. Our study demonstrated that PRDM16 deficiency in VSMCs promoted ADAM12 expression and aggravates AAA formation, which may provide potential targets for AAA treatment.
Zhenguo Wang, Xiangjie Zhao, Guizhen Zhao, Yanhong Guo, Haocheng Lu, Wenjuan Mu, Juan Zhong, Minerva Garcia-Barrio, Jifeng Zhang, Y. Eugene Chen, Lin Chang
Primary Sjogren’s syndrome (pSS) is a systemic autoimmune inflammatory disease mainly defined by T cell–dominated destruction of exocrine glands. Currently, CD8+T cells were closely related to the pathogenesis of pSS. However, the single-cell immune profiling of pSS and molecular signatures of pathogenic CD8+T cells have not been well elucidated. Our multiomics investigation identified that both T cell and B cell, especially CD8+T cells, were undergoing significant clonal expansion in pSS patients. TCR clonality analysis revealed that peripheral granzyme (GZM) K+CXCR6+CD8+T cells had higher proportion of shared clones with CD69+CD103-CD8+ tissue resident memory T (TRM) cells in labial glands in pSS. CD69+CD103-CD8+TRM cells featured by high expression of GZMK were more active and cytotoxic in pSS compared with their CD103+ counterparts. Peripheral GZMK+CXCR6+CD8+T cells with higher CD122 expression were increased and harbored a gene signature similar to TRM cells in pSS. Consistently, IL-15 was significantly elevated in pSS plasma and showed the capacity to promote differentiation of CD8+T cells into GZMK+CXCR6+CD8+T cells in a STAT5 dependent manner. Taken together, we depicted the immune landscape of pSS and further conducted comprehensive bioinformatics analysis and in vitro experimental investigation to characterize the pathogenic role and differentiation trajectory of CD8+TRM cells in pSS.
Ting Xu, Hao-Xian Zhu, Xing You, Jin-Fen Ma, Xin Li, Pan-Yue Luo, Yang Li, Zhe-Xiong Lian, Cai-Yue Gao
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