In vivo protection by antimicrobial neutralizing Abs can require the contribution of effector functions mediated by Fc-Fcγ receptor (Fc-FcγR) interactions for optimal efficacy. In influenza, broadly neutralizing anti-hemagglutinin (anti-HA) stalk mAbs require Fc-FcγR interactions to mediate in vivo protection, but strain-specific anti-HA head mAbs do not. Whether this rule applies only to anti-stalk Abs or is applicable to any broadly neutralizing Ab (bNAb) against influenza is unknown. Here, we characterized the contribution of Fc-FcγR interactions during in vivo protection for a panel of 13 anti-HA mAbs, including bNAbs and non-neutralizing Abs, against both the stalk and head domains. All classes of broadly binding anti-HA mAbs required Fc-FcγR interactions to provide protection in vivo, including those mAbs that bind the HA head and those that do not neutralize virus in vitro. Further, a broadly neutralizing anti-neuraminidase (anti-NA) mAb also required FcγRs to provide protection in vivo, but a strain-specific anti-NA mAb did not. Thus, these findings suggest that the breadth of reactivity of anti-influenza Abs, regardless of their epitope, necessitates interactions with FcγRs on effector cell populations to mediate in vivo protection. These findings will guide the design of antiviral Ab therapeutics and inform vaccine design to elicit Abs with optimal binding properties and effector functions.
David J. DiLillo, Peter Palese, Patrick C. Wilson, Jeffrey V. Ravetch
Group A streptococcal (GAS) infection induces the production of Abs that cross-react with host neuronal proteins, and these anti-GAS mimetic Abs are associated with autoimmune diseases of the CNS. However, the mechanisms that allow these Abs to cross the blood-brain barrier (BBB) and induce neuropathology remain unresolved. We have previously shown that GAS infection in mouse models induces a robust Th17 response in nasal-associated lymphoid tissue (NALT). Here, we identified GAS-specific Th17 cells in tonsils of humans naturally exposed to GAS, prompting us to explore whether GAS-specific CD4+ T cells home to mouse brains following i.n. infection. Intranasal challenge of repeatedly GAS-inoculated mice promoted migration of GAS-specific Th17 cells from NALT into the brain, BBB breakdown, serum IgG deposition, microglial activation, and loss of excitatory synaptic proteins under conditions in which no viable bacteria were detected in CNS tissue. CD4+ T cells were predominantly located in the olfactory bulb (OB) and in other brain regions that receive direct input from the OB. Together, these findings provide insight into the immunopathology of neuropsychiatric complications that are associated with GAS infections and suggest that crosstalk between the CNS and cellular immunity may be a general mechanism by which infectious agents exacerbate symptoms associated with other CNS autoimmune disorders.
Thamotharampillai Dileepan, Erica D. Smith, Daniel Knowland, Martin Hsu, Maryann Platt, Peter Bittner-Eddy, Brenda Cohen, Peter Southern, Elizabeth Latimer, Earl Harley, Dritan Agalliu, P. Patrick Cleary
Adoptive cell transfer (ACT) of purified naive, stem cell memory, and central memory T cell subsets results in superior persistence and antitumor immunity compared with ACT of populations containing more-differentiated effector memory and effector T cells. Despite a clear advantage of the less-differentiated populations, the majority of ACT trials utilize unfractionated T cell subsets. Here, we have challenged the notion that the mere presence of less-differentiated T cells in starting populations used to generate therapeutic T cells is sufficient to convey their desirable attributes. Using both mouse and human cells, we identified a T cell–T cell interaction whereby antigen-experienced subsets directly promote the phenotypic, functional, and metabolic differentiation of naive T cells. This process led to the loss of less-differentiated T cell subsets and resulted in impaired cellular persistence and tumor regression in mouse models following ACT. The T memory–induced conversion of naive T cells was mediated by a nonapoptotic Fas signal, resulting in Akt-driven cellular differentiation. Thus, induction of Fas signaling enhanced T cell differentiation and impaired antitumor immunity, while Fas signaling blockade preserved the antitumor efficacy of naive cells within mixed populations. These findings reveal that T cell subsets can synchronize their differentiation state in a process similar to quorum sensing in unicellular organisms and suggest that disruption of this quorum-like behavior among T cells has potential to enhance T cell–based immunotherapies.
Christopher A. Klebanoff, Christopher D. Scott, Anthony J. Leonardi, Tori N. Yamamoto, Anthony C. Cruz, Claudia Ouyang, Madhu Ramaswamy, Rahul Roychoudhuri, Yun Ji, Robert L. Eil, Madhusudhanan Sukumar, Joseph G. Crompton, Douglas C. Palmer, Zachary A. Borman, David Clever, Stacy K. Thomas, Shashankkumar Patel, Zhiya Yu, Pawel Muranski, Hui Liu, Ena Wang, Francesco M. Marincola, Alena Gros, Luca Gattinoni, Steven A. Rosenberg, Richard M. Siegel, Nicholas P. Restifo
The production of high-affinity antibodies by B cells is essential for pathogen clearance. Antibody affinity for antigen is increased through the affinity maturation in germinal centers (GCs). This is an iterative process in which B cells cycle between proliferation coupled with the acquisition of mutations and antigen-based positive selection, resulting in retention of the highest-affinity B cell clones. The posttranscriptional regulator microRNA-155 (miR-155) is critical for efficient affinity maturation and the maintenance of the GCs; however, the cellular and molecular mechanism by which miR-155 regulates GC responses is not well understood. Here, we utilized a miR-155 reporter mouse strain and showed that miR-155 is coexpressed with the proto-oncogene encoding c-MYC in positively selected B cells. Functionally, miR-155 protected positively selected c-MYC+ B cells from apoptosis, allowing clonal expansion of this population, providing an explanation as to why
Rinako Nakagawa, Rebecca Leyland, Michael Meyer-Hermann, Dong Lu, Martin Turner, Giuseppina Arbore, Tri Giang Phan, Robert Brink, Elena Vigorito
Type 1 diabetes (T1D) patients show abnormalities in early B cell tolerance checkpoints, resulting in the accumulation of large numbers of autoreactive B cells in their blood. Treatment with rituximab, an anti-CD20 mAb that depletes B cells, has been shown to preserve β cell function in T1D patients and improve other autoimmune diseases, including rheumatoid arthritis and multiple sclerosis. However, it remains largely unknown how anti–B cell therapy thwarts autoimmunity in these pathologies. Here, we analyzed the reactivity of Abs expressed by single, mature naive B cells from 4 patients with T1D before and 52 weeks after treatment to determine whether rituximab resets early B cell tolerance checkpoints. We found that anti–B cell therapy did not alter the frequencies of autoreactive and polyreactive B cells, which remained elevated in the blood of all patients after rituximab treatment. Moreover, the limited proliferative history of autoreactive B cells after treatment revealed that these clones were newly generated B cells and not self-reactive B cells that had escaped depletion and repopulated the periphery through homeostatic expansion. We conclude that anti–B cell therapy may provide a temporary dampening of autoimmune processes through B cell depletion. However, repletion with autoreactive B cells may explain the relapse that occurs in many autoimmune patients after anti–B cell therapy.
Nicolas Chamberlain, Christopher Massad, Tyler Oe, Tineke Cantaert, Kevan C. Herold, Eric Meffre, the Type 1 Diabetes TrialNet Pathway to Prevention Study Group
Parasitic helminth worms, such as
Leticia Monin, Kristin L. Griffiths, Wing Y. Lam, Radha Gopal, Dongwan D. Kang, Mushtaq Ahmed, Anuradha Rajamanickam, Alfredo Cruz-Lagunas, Joaquín Zúñiga, Subash Babu, Jay K. Kolls, Makedonka Mitreva, Bruce A. Rosa, Rosalio Ramos-Payan, Thomas E. Morrison, Peter J. Murray, Javier Rangel-Moreno, Edward J. Pearce, Shabaana A. Khader
Mutations of the gene encoding four-and-a-half LIM domain 1 (FHL1) are the causative factor of several X-linked hereditary myopathies that are collectively termed FHL1-related myopathies. These disorders are characterized by severe muscle dysfunction and damage. Here, we have shown that patients with idiopathic inflammatory myopathies (IIMs) develop autoimmunity to FHL1, which is a muscle-specific protein. Anti-FHL1 autoantibodies were detected in 25% of IIM patients, while patients with other autoimmune diseases or muscular dystrophies were largely anti-FHL1 negative. Anti-FHL1 reactivity was predictive for muscle atrophy, dysphagia, pronounced muscle fiber damage, and vasculitis. FHL1 showed an altered expression pattern, with focal accumulation in the muscle fibers of autoantibody-positive patients compared with a homogeneous expression in anti-FHL1–negative patients and healthy controls. We determined that FHL1 is a target of the cytotoxic protease granzyme B, indicating that the generation of FHL1 fragments may initiate FHL1 autoimmunity. Moreover, immunization of myositis-prone mice with FHL1 aggravated muscle weakness and increased mortality, suggesting a direct link between anti-FHL1 responses and muscle damage. Together, our findings provide evidence that FHL1 may be involved in the pathogenesis not only of genetic FHL1-related myopathies but also of autoimmune IIM. Importantly, these results indicate that anti-FHL1 autoantibodies in peripheral blood have promising potential as a biomarker to identify a subset of severe IIM.
Inka Albrecht, Cecilia Wick, Åsa Hallgren, Anna Tjärnlund, Kanneboyina Nagaraju, Felipe Andrade, Kathryn Thompson, William Coley, Aditi Phadke, Lina-Marcela Diaz-Gallo, Matteo Bottai, Inger Nennesmo, Karine Chemin, Jessica Herrath, Karin Johansson, Anders Wikberg, A. Jimmy Ytterberg, Roman A. Zubarev, Olof Danielsson, Olga Krystufkova, Jiri Vencovsky, Nils Landegren, Marie Wahren-Herlenius, Leonid Padyukov, Olle Kämpe, Ingrid E. Lundberg
A high intake of dietary salt (NaCl) has been implicated in the development of hypertension, chronic inflammation, and autoimmune diseases. We have recently shown that salt has a proinflammatory effect and boosts the activation of Th17 cells and the activation of classical, LPS-induced macrophages (M1). Here, we examined how the activation of alternative (M2) macrophages is affected by salt. In stark contrast to Th17 cells and M1 macrophages, high salt blunted the alternative activation of BM-derived mouse macrophages stimulated with IL-4 and IL-13, M(IL-4+IL-13) macrophages. Salt-induced reduction of M(IL-4+IL-13) activation was not associated with increased polarization toward a proinflammatory M1 phenotype. In vitro, high salt decreased the ability of M(IL-4+IL-13) macrophages to suppress effector T cell proliferation. Moreover, mice fed a high salt diet exhibited reduced M2 activation following chitin injection and delayed wound healing compared with control animals. We further identified a high salt–induced reduction in glycolysis and mitochondrial metabolic output, coupled with blunted AKT and mTOR signaling, which indicates a mechanism by which NaCl inhibits full M2 macrophage activation. Collectively, this study provides evidence that high salt reduces noninflammatory innate immune cell activation and may thus lead to an overall imbalance in immune homeostasis.
Katrina J. Binger, Matthias Gebhardt, Matthias Heinig, Carola Rintisch, Agnes Schroeder, Wolfgang Neuhofer, Karl Hilgers, Arndt Manzel, Christian Schwartz, Markus Kleinewietfeld, Jakob Voelkl, Valentin Schatz, Ralf A. Linker, Florian Lang, David Voehringer, Mark D. Wright, Norbert Hubner, Ralf Dechend, Jonathan Jantsch, Jens Titze, Dominik N. Müller
FOXP3+ Tregs are central for the maintenance of self-tolerance and can be defective in autoimmunity. In multiple sclerosis and type-1 diabetes, dysfunctional self-tolerance is partially mediated by a population of IFNγ-secreting Tregs. It was previously reported that increased NaCl concentrations promote the induction of proinflammatory Th17 cells and that high-salt diets exacerbate experimental models of autoimmunity. Here, we have shown that increasing NaCl, either in vitro or in murine models via diet, markedly impairs Treg function. NaCl increased IFNγ secretion in Tregs, and reducing IFNγ — either by neutralization with anti-IFNγ antibodies or shRNA-mediated knockdown — restored suppressive activity in Tregs. The heightened IFNγ secretion and loss of Treg function were mediated by the serum/glucocorticoid-regulated kinase (SGK1). A high-salt diet also impaired human Treg function and was associated with the induction of IFNγ-secreting Tregs in a xenogeneic graft-versus-host disease model and in adoptive transfer models of experimental colitis. Our results demonstrate a putative role for an environmental factor that promotes autoimmunity by inducing proinflammatory responses in CD4 effector cells and Treg pathways.
Amanda L. Hernandez, Alexandra Kitz, Chuan Wu, Daniel E. Lowther, Donald M. Rodriguez, Nalini Vudattu, Songyan Deng, Kevan C. Herold, Vijay K. Kuchroo, Markus Kleinewietfeld, David A. Hafler
Autosomal recessive mutations in proteasome subunit β 8 (
Anja Brehm, Yin Liu, Afzal Sheikh, Bernadette Marrero, Ebun Omoyinmi, Qing Zhou, Gina Montealegre, Angelique Biancotto, Adam Reinhardt, Adriana Almeida de Jesus, Martin Pelletier, Wanxia L. Tsai, Elaine F. Remmers, Lela Kardava, Suvimol Hill, Hanna Kim, Helen J. Lachmann, Andre Megarbane, Jae Jin Chae, Jilian Brady, Rhina D. Castillo, Diane Brown, Angel Vera Casano, Ling Gao, Dawn Chapelle, Yan Huang, Deborah Stone, Yongqing Chen, Franziska Sotzny, Chyi-Chia Richard Lee, Daniel L. Kastner, Antonio Torrelo, Abraham Zlotogorski, Susan Moir, Massimo Gadina, Phil McCoy, Robert Wesley, Kristina Rother, Peter W. Hildebrand, Paul Brogan, Elke Krüger, Ivona Aksentijevich, Raphaela Goldbach-Mansky
Patients with mutations of the recombination-activating genes (
Jolan E. Walter, Lindsey B. Rosen, Krisztian Csomos, Jacob M. Rosenberg, Divij Mathew, Marton Keszei, Boglarka Ujhazi, Karin Chen, Yu Nee Lee, Irit Tirosh, Kerry Dobbs, Waleed Al-Herz, Morton J. Cowan, Jennifer Puck, Jack J. Bleesing, Michael S. Grimley, Harry Malech, Suk See De Ravin, Andrew R. Gennery, Roshini S. Abraham, Avni Y. Joshi, Thomas G. Boyce, Manish J. Butte, Kari C. Nadeau, Imelda Balboni, Kathleen E. Sullivan, Javeed Akhter, Mehdi Adeli, Reem A. El-Feky, Dalia H. El-Ghoneimy, Ghassan Dbaibo, Rima Wakim, Chiara Azzari, Paolo Palma, Caterina Cancrini, Kelly Capuder, Antonio Condino-Neto, Beatriz T. Costa-Carvalho, Joao Bosco Oliveira, Chaim Roifman, David Buchbinder, Attila Kumanovics, Jose Luis Franco, Tim Niehues, Catharina Schuetz, Taco Kuijpers, Christina Yee, Janet Chou, Michel J. Masaad, Raif Geha, Gulbu Uzel, Rebecca Gelman, Steven M. Holland, Mike Recher, Paul J. Utz, Sarah K. Browne, Luigi D. Notarangelo
Mucosal-associated invariant T cells (MAITs) have potent antimicrobial activity and are abundant in humans (5%–10% in blood). Despite strong evolutionary conservation of the invariant TCR-α chain and restricting molecule MR1, this population is rare in laboratory mouse strains (≈0.1% in lymphoid organs), and lack of an appropriate mouse model has hampered the study of MAIT biology. Herein, we show that MAITs are 20 times more frequent in clean wild-derived inbred CAST/EiJ mice than in C57BL/6J mice. Increased MAIT frequency was linked to one CAST genetic trait that mapped to the TCR-α locus and led to higher usage of the distal Vα segments, including Vα19. We generated a MAIThi congenic strain that was then crossed to a transgenic
Yue Cui, Katarzyna Franciszkiewicz, Yvonne K. Mburu, Stanislas Mondot, Lionel Le Bourhis, Virginie Premel, Emmanuel Martin, Alexandra Kachaner, Livine Duban, Molly A. Ingersoll, Sylvie Rabot, Jean Jaubert, Jean-Pierre De Villartay, Claire Soudais, Olivier Lantz
Granulomatosis with polyangiitis (GPA) is a systemic necrotizing vasculitis that is associated with granulomatous inflammation and the presence of anti-neutrophil cytoplasmic antibodies (ANCAs) directed against proteinase 3 (PR3). We previously determined that PR3 on the surface of apoptotic neutrophils interferes with induction of antiinflammatory mechanisms following phagocytosis of these cells by macrophages. Here, we demonstrate that enzymatically active membrane-associated PR3 on apoptotic cells triggered secretion of inflammatory cytokines, including granulocyte CSF (G-CSF) and chemokines. This response required the IL-1R1/MyD88 signaling pathway and was dependent on the synthesis of NO, as macrophages from animals lacking these pathways did not exhibit a PR3-associated proinflammatory response. The PR3-induced microenvironment facilitated recruitment of inflammatory cells, such as macrophages, plasmacytoid DCs (pDCs), and neutrophils, which were observed in close proximity within granulomatous lesions in the lungs of GPA patients. In different murine models of apoptotic cell injection, the PR3-induced microenvironment instructed pDC-driven Th9/Th2 cell generation. Concomitant injection of anti-PR3 ANCAs with PR3-expressing apoptotic cells induced a Th17 response, revealing a GPA-specific mechanism of immune polarization. Accordingly, circulating CD4+ T cells from GPA patients had a skewed distribution of Th9/Th2/Th17. These results reveal that PR3 disrupts immune silencing associated with clearance of apoptotic neutrophils and provide insight into how PR3 and PR3-targeting ANCAs promote GPA pathophysiology.
Arnaud Millet, Katherine R. Martin, Francis Bonnefoy, Philippe Saas, Julie Mocek, Manal Alkan, Benjamin Terrier, Anja Kerstein, Nicola Tamassia, Senthil Kumaran Satyanarayanan, Amiram Ariel, Jean-Antoine Ribeil, Loïc Guillevin, Marco A. Cassatella, Antje Mueller, Nathalie Thieblemont, Peter Lamprecht, Luc Mouthon, Sylvain Perruche, Véronique Witko-Sarsat
Polarized activation of adipose tissue macrophages (ATMs) is crucial for maintaining adipose tissue function and mediating obesity-associated cardiovascular risk and metabolic abnormalities; however, the regulatory network of this key process is not well defined. Here, we identified a PPARγ/microRNA-223 (miR-223) regulatory axis that controls macrophage polarization by targeting distinct downstream genes to shift the cellular response to various stimuli. In BM-derived macrophages, PPARγ directly enhanced miR-223 expression upon exposure to Th2 stimuli. ChIP analysis, followed by enhancer reporter assays, revealed that this effect was mediated by PPARγ binding 3 PPARγ regulatory elements (PPREs) upstream of the pre–miR-223 coding region. Moreover, deletion of miR-223 impaired PPARγ-dependent macrophage alternative activation in cells cultured ex vivo and in mice fed a high-fat diet. We identified
Wei Ying, Alexander Tseng, Richard Cheng-An Chang, Andrew Morin, Tyler Brehm, Karen Triff, Vijayalekshmi Nair, Guoqing Zhuang, Hui Song, Srikanth Kanameni, Haiqing Wang, Michael C. Golding, Fuller W. Bazer, Robert S. Chapkin, Stephen Safe, Beiyan Zhou
IgG molecules exert both pro- and antiinflammatory effector functions based on the composition of the fragment crystallizable (Fc) domain glycan. Sialylated IgG Fc domains have antiinflammatory properties that are attributed to their ability to increase the activation threshold of innate effector cells to immune complexes by stimulating the upregulation of the inhibitory Fcγ receptor IIB (FcγRIIB). Here, we report that IgG Fc sialylation of human monoclonal IgG1 molecules impairs their efficacy to induce complement-mediated cytotoxicity (CDC). Fc sialylation of a CD20-targeting antibody had no impact on antibody-dependent cellular cytotoxicity and did not change the affinity of the antibody for activating Fcγ receptors. In contrast, the presence of sialic acid abrogated the increased binding of C1q to Fc-galactosylated IgG1 and resulted in decreased levels of C3b deposition on the cell surface. Similar to monoclonal antibodies, sialic acid inhibited the increased C1q binding to galactosylated Fc fragments in human polyclonal IgG. In sera derived from patients with chronic inflammatory demyelinating polyneuropathy, an autoimmune disease of the peripheral nervous system in which humoral immune responses mediate tissue damage, induction of IgG Fc sialylation was associated with clinical disease remission. Thus, impairment of CDC represents an FcγR-independent mechanism by which Fc-sialylated glycovariants might limit proinflammatory IgG effector functions.
Isaak Quast, Christian W. Keller, Michael A. Maurer, John P. Giddens, Björn Tackenberg, Lai-Xi Wang, Christian Münz, Falk Nimmerjahn, Marinos C. Dalakas, Jan D. Lünemann
IL-17–producing CD4+ T cells (Th17 cells) have well-described pathogenic roles in tissue inflammation and autoimmune diseases, such as experimental autoimmune encephalomyelitis (EAE); however, the involvement of IL-21 in these processes has remained controversial. While IL-21 is an essential autocrine amplification factor for differentiation of Th17 cells, the loss of IL-21 or IL-21 receptor (IL-21R) does not protect mice from actively induced EAE. Here, we utilized a transgenic EAE mouse model, in which T and B cells overexpress receptors for myelin oligodendrocyte glycoprotein (MOG) (referred to as 2D2xTH mice), and demonstrated that IL-21 is critical for the development of a variant form of spontaneous EAE in these animals.
Youjin Lee, Meike Mitsdoerffer, Sheng Xiao, Guangxiang Gu, Raymond A. Sobel, Vijay K. Kuchroo
Coinhibitory receptors are critical for the maintenance of immune homeostasis. Upregulation of these receptors on effector T cells terminates T cell responses, while their expression on Tregs promotes their suppressor function. Understanding the function of coinhibitory receptors in effector T cells and Tregs is crucial, as therapies that target coinhibitory receptors are currently at the forefront of treatment strategies for cancer and other chronic diseases. T cell Ig and ITIM domain (TIGIT) is a recently identified coinhibitory receptor that is found on the surface of a variety of lymphoid cells, and its role in immune regulation is just beginning to be elucidated. We examined TIGIT-mediated immune regulation in different murine cancer models and determined that TIGIT marks the most dysfunctional subset of CD8+ T cells in tumor tissue as well as tumor-tissue Tregs with a highly active and suppressive phenotype. We demonstrated that TIGIT signaling in Tregs directs their phenotype and that TIGIT primarily suppresses antitumor immunity via Tregs and not CD8+ T cells. Moreover, TIGIT+ Tregs upregulated expression of the coinhibitory receptor TIM-3 in tumor tissue, and TIM-3 and TIGIT synergized to suppress antitumor immune responses. Our findings provide mechanistic insight into how TIGIT regulates immune responses in chronic disease settings.
Sema Kurtulus, Kaori Sakuishi, Shin-Foong Ngiow, Nicole Joller, Dewar J. Tan, Michele W.L. Teng, Mark J. Smyth, Vijay K. Kuchroo, Ana C. Anderson
Erythropoiesis is an important response to certain types of stress, including hypoxia, hemorrhage, bone marrow suppression, and anemia, that result in inadequate tissue oxygenation. This stress-induced erythropoiesis is distinct from basal red blood cell generation; however, neither the cellular nor the molecular factors that regulate this process are fully understood. Here, we report that type 1 conventional dendritic cells (cDC1s), which are defined by expression of CD8α in the mouse and XCR1 and CLEC9 in humans, are critical for induction of erythropoiesis in response to stress. Specifically, using murine models, we determined that engagement of a stress sensor, CD24, on cDC1s upregulates expression of the Kit ligand stem cell factor on these cells. The increased expression of stem cell factor resulted in Kit-mediated proliferative expansion of early erythroid progenitors and, ultimately, transient reticulocytosis in the circulation. Moreover, this stress response was triggered in part by alarmin recognition and was blunted in CD24 sensor– and CD8α+ DC-deficient animals. The contribution of the cDC1 subset to the initiation of stress erythropoiesis was distinct from the well-recognized role of macrophages in supporting late erythroid maturation. Together, these findings offer insight into the mechanism of stress erythropoiesis and into disorders of erythrocyte generation associated with stress.
Taeg S. Kim, Mark Hanak, Paul C. Trampont, Thomas J. Braciale
We recently reported that abundant deposits of the extracellular matrix polysaccharide hyaluronan (HA) are characteristic of autoimmune insulitis in patients with type 1 diabetes (T1D), but the relevance of these deposits to disease was unclear. Here, we have demonstrated that HA is critical for the pathogenesis of autoimmune diabetes. Using the DO11.10xRIPmOVA mouse model of T1D, we determined that HA deposits are temporally and anatomically associated with the development of insulitis. Moreover, treatment with an inhibitor of HA synthesis, 4-methylumbelliferone (4-MU), halted progression to diabetes even after the onset of insulitis. Similar effects were seen in the NOD mouse model, and in these mice, 1 week of treatment was sufficient to prevent subsequent diabetes. 4-MU reduced HA accumulation, constrained effector T cells to nondestructive insulitis, and increased numbers of intraislet FOXP3+ Tregs. Consistent with the observed effects of 4-MU treatment, Treg differentiation was inhibited by HA and anti-CD44 antibodies and rescued by 4-MU in an ERK1/2-dependent manner. These data may explain how peripheral immune tolerance is impaired in tissues under autoimmune attack, including islets in T1D. We propose that 4-MU, already an approved drug used to treat biliary spasm, could be repurposed to prevent, and possibly treat, T1D in at-risk individuals.
Nadine Nagy, Gernot Kaber, Pamela Y. Johnson, John A. Gebe, Anton Preisinger, Ben A. Falk, Vivekananda G. Sunkari, Michel D. Gooden, Robert B. Vernon, Marika Bogdani, Hedwich F. Kuipers, Anthony J. Day, Daniel J. Campbell, Thomas N. Wight, Paul L. Bollyky
Wiskott-Aldrich syndrome (WAS) is an X-linked immunodeficiency characterized by microthrombocytopenia, eczema, and high susceptibility to developing tumors and autoimmunity. Recent evidence suggests that B cells may be key players in the pathogenesis of autoimmunity in WAS. Here, we assessed whether WAS protein deficiency (WASp deficiency) affects the establishment of B cell tolerance by testing the reactivity of recombinant antibodies isolated from single B cells from 4 WAS patients before and after gene therapy (GT). We found that pre-GT WASp-deficient B cells were hyperreactive to B cell receptor stimulation (BCR stimulation). This hyperreactivity correlated with decreased frequency of autoreactive new emigrant/transitional B cells exiting the BM, indicating that the BCR signaling threshold plays a major role in the regulation of central B cell tolerance. In contrast, mature naive B cells from WAS patients were enriched in self-reactive clones, revealing that peripheral B cell tolerance checkpoint dysfunction is associated with impaired suppressive function of WAS regulatory T cells. The introduction of functional WASp by GT corrected the alterations of both central and peripheral B cell tolerance checkpoints. We conclude that WASp plays an important role in the establishment and maintenance of B cell tolerance in humans and that restoration of WASp by GT is able to restore B cell tolerance in WAS patients.
Francesca Pala, Henner Morbach, Maria Carmina Castiello, Jean-Nicolas Schickel, Samantha Scaramuzza, Nicolas Chamberlain, Barbara Cassani, Salome Glauzy, Neil Romberg, Fabio Candotti, Alessandro Aiuti, Marita Bosticardo, Anna Villa, Eric Meffre