Osteoarthritis (OA) is a leading cause of disability, globally. Despite an emerging role for synovial inflammation in OA pathogenesis, attempts to target inflammation therapeutically have had limited success. A better understanding of the cellular and molecular processes occurring in the OA synovium is needed to develop novel therapeutics. We investigated macrophage phenotype and gene expression in synovial tissue of OA and inflammatory-arthritis (IA) patients. Compared with IA, OA synovial tissue contained higher but variable proportions of macrophages (P < 0.001). These macrophages exhibited an activated phenotype, expressing folate receptor-2 and CD86, and displayed high phagocytic capacity. RNA sequencing of synovial macrophages revealed 2 OA subgroups. Inflammatory-like OA (iOA) macrophages are closely aligned to IA macrophages and are characterized by a cell proliferation signature. In contrast, classical OA (cOA) macrophages display cartilage remodeling features. Supporting these findings, when compared with cOA, iOA synovial tissue contained higher proportions of macrophages (P < 0.01), expressing higher levels of the proliferation marker Ki67 (P < 0.01). These data provide new insight into the heterogeneity of OA synovial tissue and suggest distinct roles of macrophages in pathogenesis. Our findings could lead to the stratification of OA patients for suitable disease-modifying treatments and the identification of novel therapeutic targets.
Matthew J. Wood, Adam Leckenby, Gary Reynolds, Rachel Spiering, Arthur G. Pratt, Kenneth S. Rankin, John D. Isaacs, Muzlifah A. Haniffa, Simon Milling, Catharien M.U. Hilkens
Allergic eosinophilic asthma is a chronic condition causing airway remodeling resulting in lung dysfunction. We observed that expression of Sirtuin 2 (Sirt2), a histone deacetylase, regulates the recruitment of eosinophils after sensitization and challenge with a triple-antigen: dust mite, ragweed and Aspergillus fumigatus (DRA). Our data demonstrate that IL-4 regulates the expression of Sirt2 isoform 3/5. Pharmacological inhibition of Sirt2 by AGK2 resulted in diminished cellular recruitment, decreased CCL17/TARC, and reduced goblet cell hyperplasia. YM1 and Fizz1 expression was reduced in AGK2-treated, IL-4-stimulated lung macrophages in vitro as well as in lung macrophages from AGK2-DRA challenged mice. Conversely, overexpression of Sirt2 resulted in increased cellular recruitment, CCL17 production, and goblet cell hyperplasia following DRA challenge. Sirt2 isoform 3/5 was upregulated in primary human alveolar macrophages following IL-4 and AGK2 treatment resulted in reduced CCL17 and markers of alternative activation. These gain-of-function and loss-of-function studies indicate that Sirt2 could be developed as a treatment for eosinophilic asthma.
Yong Gyu Lee, Brenda F. Reader, Derrick Herman, Adam Streicher, Joshua A. Englert, Mathias Ziegler, Sangwoon Chung, Manjula Karpurapu, Gye Young Park, John W. Christman, Megan N. Ballinger
Ricin toxin (RT) ranks at the top of the list of bioweapons of concern to civilian and military personnel alike, due to its high potential for morbidity and mortality after inhalation. In nonhuman primates, aerosolized ricin triggers severe acute respiratory distress characterized by perivascular and alveolar edema, neutrophilic infiltration, and severe necrotizing bronchiolitis and alveolitis. There are currently no approved countermeasures for ricin intoxication. Here, we report the therapeutic potential of a humanized mAb against an immunodominant epitope on ricin’s enzymatic A chain (RTA). Rhesus macaques that received i.v. huPB10 4 hours after a lethal dose of ricin aerosol exposure survived toxin challenge, whereas control animals succumbed to ricin intoxication within 30 hours. Antibody intervention at 12 hours resulted in the survival of 1 of 5 monkeys. Changes in proinflammatory cytokine, chemokine, and growth factor profiles in bronchial alveolar lavage fluids before and after toxin challenge successfully clustered animals by treatment group and survival, indicating a relationship between local tissue damage and experimental outcome. This study represents the first demonstration, to our knowledge, in nonhuman primates that the lethal effects of inhalational ricin exposure can be negated by a drug candidate, and it opens up a path forward for product development.
Chad J. Roy, Dylan J. Ehrbar, Natasha Bohorova, Ognian Bohorov, Do Kim, Michael Pauly, Kevin Whaley, Yinghui Rong, Fernando J. Torres-Velez, Ellen S. Vitetta, Peter J. Didier, Lara Doyle-Meyers, Larry Zeitlin, Nicholas J. Mantis
Psoralen plus UVA (PUVA) is an effective therapy for mycosis fungoides (MF), the skin-limited variant of cutaneous T cell lymphoma (CTCL). In low-burden patients, PUVA reduced or eradicated malignant T cells and induced clonal expansion of CD8+ T cells associated with malignant T cell depletion. High-burden patients appeared to clinically improve but large numbers of malignant T cells persisted in skin. Clinical improvement was linked to turnover of benign T cell clones but not to malignant T cell reduction. Benign T cells were associated with the Th2-recruiting chemokine CCL18 before therapy and with the Th1-recruiting chemokines CXCL9, CXCL10, and CXCL11 after therapy, suggesting a switch from Th2 to Th1. Inflammation was correlated with OX40L and CD40L gene expression; immunostaining localized these receptors to CCL18-expressing c-Kit+ dendritic cells that clustered together with CD40+OX40+ benign and CD40+CD40L+ malignant T cells, creating a proinflammatory synapse in skin. Our data suggest that visible inflammation in CTCL results from the recruitment and activation of benign T cells by c-Kit+OX40L+CD40L+ dendritic cells and that this activation may provide tumorigenic signals. Targeting c-Kit, OX40, and CD40 signaling may be novel therapeutic avenues for the treatment of MF.
Pablo Vieyra-Garcia, Jack D. Crouch, John T. O’Malley, Edward W. Seger, Chao H. Yang, Jessica E. Teague, Anna Maria Vromans, Ahmed Gehad, Thet Su Win, Zizi Yu, Elizabeth L. Lowry, Jung-Im Na, Alain H. Rook, Peter Wolf, Rachael A. Clark
CD4+ follicular helper T (Tfh) cells are specialized providers of T cell help to B cells and can function as pathogenic mediators of murine antibody-dependent chronic graft-versus-host disease (GvHD). Using a parent→F1 model of lupus-like chronic GvHD, in which Tfh cell and germinal center (GC) B cell differentiation occurs over 14 days, we demonstrate that absence of CD4+ T cell–expressed C5a receptor 1 (C5ar1) or pharmacological C5aR1 blockade abrogated generation/expansion of Tfh cells, GC B cells, and autoantibodies. In a Tfh cell–dependent model of chronic GvHD manifested by bronchiolitis obliterans syndrome (BOS), C5aR1 antagonism initiated in mice with established disease ameliorated BOS and abolished the associated differentiation of Tfh and GC B cells. Guided by RNA-sequencing data, mechanistic studies performed using murine and human T cells showed that C5aR1 signaling amplifies IL-6–dependent expression of the transcription factor c-MAF and the cytokine IL-21 via phosphorylating phosphokinase B (AKT) and activating the mammalian target of rapamycin (mTOR). In addition to linking C5aR1-initiated signaling to Tfh cell differentiation, our findings suggest that C5aR1 may be a useful therapeutic target for prevention and/or treatment of individuals with Tfh cell–dependent diseases, including those chronic GvHD patients who have anti-host reactive antibodies.
Divya A. Verghese, Nicholas Chun, Katelyn Paz, Miguel Fribourg, Trent M. Woodruff, Ryan Flynn, Yuan Hu, Huabao Xiong, Weijia Zhang, Zhengzi Yi, Jing Du, Bruce R. Blazar, Peter S. Heeger
Tregs are impaired in human systemic lupus erythematosus (SLE) and contribute to effector T cell activation. However, the mechanisms responsible for the Treg deficiency in SLE remain unclear. We hypothesized that the OX40L/OX40 axis is implicated in Treg and regulatory follicular helper T (Tfr) cell dysfunction in human SLE. OX40L/OX40 axis engagement on Tregs and Tfr cells not only specifically impaired their ability to regulate effector T cell proliferation, but also their ability to suppress T follicular helper (Tfh) cell–dependent B cell activation and immunoglobulin secretion. Antigen-presenting cells from patients with active SLE mediated Treg dysfunction in an OX40L-dependent manner, and OX40L-expressing cells colocalized with Foxp3+ cells in active SLE skin lesions. Engagement of the OX40L/OX40 axis resulted in Foxp3 downregulation in Tregs, and expression in SLE Tregs correlated with the proportion of circulating OX40L-expressing myeloid DCs. These data support that OX40L/OX40 signals are implicated in Treg dysfunction in human SLE. Thus, blocking the OX40L/OX40 axis appears to be a promising therapeutic strategy.
Clément Jacquemin, Jean-François Augusto, Marc Scherlinger, Noémie Gensous, Edouard Forcade, Isabelle Douchet, Emeline Levionnois, Christophe Richez, Estibaliz Lazaro, Pierre Duffau, Marie-Elise Truchetet, Julien Seneschal, Lionel Couzi, Jean-Luc Pellegrin, Jean-François Viallard, Thierry Schaeverbeke, Virginia Pascual, Cécile Contin-Bordes, Patrick Blanco
CD141+ DC are implicated in antiviral and antitumor immunity. However, mechanistic studies in autoimmune disease are limited. This is the first study to our knowledge examining CD141+ DC in autoimmune disease, specifically inflammatory arthritis (IA). We identified significant enrichment of CD141+ DC in the inflamed synovial joint, which were transcriptionally distinct from IA and healthy control (HC) blood CD141+ DC and significantly more activated, and they exhibited increased responsiveness to TLR3. Synovial CD141+ DC represent a bone fide CD141+ DC population that is distinct from CD1c+ DC. Synovial CD141+ DC induced higher levels of CD4+ and CD8+ T cell activation compared with their peripheral blood counterparts, as made evident by expression of IFN-γ, TNF-α, and granulocyte-macrophage CSF (GMCSF). Autologous synovial CD141+ DC cocultures also induce higher levels of these cytokines, further highlighting their contribution to synovial inflammation. Synovial CD141+ DC–T cell interactions had the ability to further activate synovial fibroblasts, inducing adhesive and invasive pathogenic mechanisms. Furthermore, we identify a mechanism in which synovial CD141+ DC are activated, via ligation of the hypoxia-inducible immune-amplification receptor TREM-1, which increased synovial CD141+ DC activation, migratory capacity, and proinflammatory cytokines. Thus, synovial CD141+ DC display unique mechanistic and transcriptomic signatures, which are distinguishable from blood CD141+ DC and can contribute to synovial joint inflammation.
Mary Canavan, Alice M. Walsh, Vipul Bhargava, Sarah M. Wade, Trudy McGarry, Viviana Marzaioli, Barry Moran, Monika Biniecka, Hannah Convery, Siobhan Wade, Carl Orr, Ronan Mullan, Jean M. Fletcher, Sunil Nagpal, Douglas J. Veale, Ursula Fearon
New techniques for single-cell analysis have led to insights into hematopoiesis and the immune system, but the ability of these techniques to cross-validate and reproducibly identify the biological variation in diverse human samples is currently unproven. We therefore performed a comprehensive assessment of human bone marrow cells using both single-cell RNA sequencing and multiparameter flow cytometry from 20 healthy adult human donors across a broad age range. These data characterize variation between healthy donors as well as age-associated changes in cell population frequencies. Direct comparison of techniques revealed discrepancy in the quantification of T lymphocyte and natural killer cell populations. Orthogonal validation of immunophenotyping using mass cytometry demonstrated a strong correlation with flow cytometry. Technical replicates using single-cell RNA sequencing matched robustly, while biological replicates showed variation. Given the increasing use of single-cell technologies in translational research, this resource serves as an important reference data set and highlights opportunities for further refinement.
Karolyn A. Oetjen, Katherine E. Lindblad, Meghali Goswami, Gege Gui, Pradeep K. Dagur, Catherine Lai, Laura W. Dillon, J. Philip McCoy, Christopher S. Hourigan
Immune checkpoint blockade (ICB) provides clinical benefit to a minority of patients with urothelial carcinoma (UC). The role of CD4+ T cells in ICB-induced antitumor activity is not well defined; however, CD4+ T cells are speculated to play a supportive role in the development of CD8+ T cells that kill tumor cells after recognition of tumor antigens presented by MHC class I. To investigate the mechanisms of ICB-induced activity against UC, we developed mouse organoid-based transplantable models that have histologic and genetic similarity to human bladder cancer. We found that ICB can induce tumor rejection and protective immunity with these systems in a manner dependent on CD4+ T cells but not reliant on CD8+ T cells. Evaluation of tumor infiltrates and draining lymph nodes after ICB revealed expansion of IFN-γ–producing CD4+ T cells. Tumor cells in this system express MHC class I, MHC class II, and the IFN-γ receptor (Ifngr1), but none were necessary for ICB-induced tumor rejection. IFN-γ neutralization blocked ICB activity, and, in mice depleted of CD4+ T cells, IFN-γ ectopically expressed in the tumor microenvironment was sufficient to inhibit growth of tumors in which the epithelial compartment lacked Ifngr1. Our findings suggest unappreciated CD4+ T cell–dependent mechanisms of ICB activity, principally mediated through IFN-γ effects on the microenvironment.
Yuji Sato, Jennifer K. Bolzenius, Abdallah M. Eteleeb, Xinming Su, Christopher A. Maher, Jennifer K. Sehn, Vivek K. Arora
The analysis and validation of flow cytometry–based biomarkers in clinical studies are limited by the lack of standardized protocols that are reproducible across multiple centers and suitable for use with either unfractionated blood or cryopreserved PBMCs. Here we report the development of a platform that standardizes a set of flow cytometry panels across multiple centers, with high reproducibility in blood or PBMCs from either healthy subjects or patients 100 days after hematopoietic stem cell transplantation. Inter-center comparisons of replicate samples showed low variation, with interindividual variation exceeding inter-center variation for most populations (coefficients of variability <20% and interclass correlation coefficients >0.75). Exceptions included low-abundance populations defined by markers with indistinct expression boundaries (e.g., plasmablasts, monocyte subsets) or populations defined by markers sensitive to cryopreservation, such as CD62L and CD45RA. Automated gating pipelines were developed and validated on an independent data set, revealing high Spearman’s correlations (rs >0.9) with manual analyses. This workflow, which includes pre-formatted antibody cocktails, standardized protocols for acquisition, and validated automated analysis pipelines, can be readily implemented in multicenter clinical trials. This approach facilitates the collection of robust immune phenotyping data and comparison of data from independent studies.
Sabine Ivison, Mehrnoush Malek, Rosa V. Garcia, Raewyn Broady, Anne Halpin, Manon Richaud, Rollin F. Brant, Szu-I Wang, Mathieu Goupil, Qingdong Guan, Peter Ashton, Jason Warren, Amr Rajab, Simon Urschel, Deepali Kumar, Mathias Streitz, Birgit Sawitzki, Stephan Schlickeiser, Janetta J. Bijl, Donna A. Wall, Jean-Sebastien Delisle, Lori J. West, Ryan R. Brinkman, Megan K. Levings
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