Immunology
Abstract
Rheumatoid arthritis (RA) is characterized by joint inflammation and bone erosion. Understanding cytokine pathways, particularly those targeting TNF, is crucial for understanding pathology and advancing treatment development. Arid5a is a noncanonical RNA binding protein (RBP) that augments inflammation through stabilizing proinflammatory mRNAs and enhancing protein translation. We examined published datasets for ARID5A in human RA blood, T cells, and synovial tissues. A stromal cell line, epithelial cells, and primary synovial fibroblasts were used to assess the effect of TNF on Arid5a expression, localization, and function. To determine how TNF induces Arid5a, WT or Traf2–/– stromal cells were treated with NIK or IKK inhibitors. To evaluate the necessity of Arid5a in arthritis progression, Arid5a–/– mice were subjected to collagen-induced arthritis. ARID5A was elevated in patients with RA and reduced by anti-TNF therapy. TNF upregulated Arid5a through the NF-κB1/TRAF2 pathway, causing cytoplasmic relocalization. Arid5a stabilized proinflammatory transcripts and enhanced expression of chemokines that drive RA. Arid5a–/– mice were resistant to collagen-induced arthritis correlating with reduced Th17 cells in synovial tissue. Thus, Arid5a serves as a newly recognized signaling intermediate downstream of TNF that is elevated in human RA and drives pathology in murine CIA, potentially positioning this RBP as a possible therapeutic target.
Authors
Yang Li, Ipsita Dey, Shachi P. Vyas, Alzbeta Synackova, Decheng Li, Erik Lubberts, Dana P. Ascherman, Peter Draber, Sarah L. Gaffen
Abstract
Treatment with anti-CD3 monoclonal antibody (mAb) can delay or prevent type 1 diabetes in mice and humans by modulating the immune-mediated destruction of β cells. A single course of treatment may have lasting efficacy, but the mechanisms that account for these prolonged effects, i.e., “operational tolerance,” are not clear. Here, we used paired single-cell RNA and T cell receptor sequencing to characterize islet-infiltrating T cells and their counterpart in paired pancreatic lymph nodes from anti-CD3 mAb–treated nonobese diabetic (NOD) mice in remission. We found that after anti-CD3 mAb treatment, T cells that infiltrate the islets are more heterogeneous and have hybrid features including characteristics of T stem cell–like memory and reduced effector function compared with those from untreated prediabetic NOD mice. Autoantigen-reactive CD8+ T cells persist after treatment, but they also show features of stemness and reduced pathogenicity. Our findings describe the reshaping of islet-infiltrating and autoreactive T cells and β cells that lead to operational, but tenuous, tolerance to autoimmune diabetes following anti-CD3 mAb treatment.
Authors
Ying Wu, Maxwell Spurrell, Ana Lledó-Delgado, Songyan Deng, Dejiang Wang, Yang Liu, Mahsa Nouri Barkestani, Ana Luisa Perdigoto, Kevan C. Herold
Abstract
Acute severe joint pain is a major symptom in gouty arthritis (GA), and its adequate treatment represents an unmet medical need. Mrgprb2, a specific mast cell receptor, has been implicated in the generation of chronic pain by mobilizing mast cell degranulation, yet its significance in GA pain and joint inflammation is still not well defined. Here, we found that Mrgprb2 was expressed in mouse synovial mast cells. In a murine model of GA, acute blockade or genetic deletion of Mrgprb2 significantly attenuated arthritis pain and hyperexcitability of joint nociceptors with significant reductions in innate immune cell recruitment in the synovium. Under naive conditions, activation of synovial Mrgprb2 was sufficient to excite peripheral terminals of joint nociceptors to induce acute joint hypernociception via the mobilization of mast cell degranulation. Additionally, the level of the neuropeptide substance P (SP) was elevated in the synovium of GA model mice. Using humanized MRGPRX2-knockin mice, we revealed that SP contributed to joint pain and inflammation by activating mast cells through Mrgprb2/MRGPRX2. These findings suggest that synovial mast cell–expressed Mrgprb2/MRGPRX2 merits consideration as a key neuroimmune player and a potential therapeutic target for treating GA pain and joint inflammation.
Authors
Lin Yang, Chengxi Liu, Jin Xiao, Yu Song, Huan Chen, Dan Li, Cong Zou, Tao Hong, Yinglan Liu, Dake Qi, Nathachit Limjunyawong, Wenjie Liu, Lintao Qu
Abstract
Functional antibody responses to malaria transmission-blocking vaccines (TBVs) are assessed using the Standard Membrane Feeding Assay (SMFA). This assay quantifies percentage reduction of oocyst levels in mosquitoes fed gametocytes mixed with antisera/antibodies, referred to as transmission-reducing activity (TRA). As TBVs advance to large clinical trials, new scalable assays are needed to characterize vaccine responses. Here, we developed an epitope-specific competitive ELISA platform (P230Compete) for TBV candidate Pfs230D1, based on single-chain variable fragments (scFv) against epitopes recognized by human monoclonal antibodies with high TRA. We quantified functional epitope-specific antibody responses (F) in Phase 1 Pfs230D1-EPA/AS01 vaccine trial participants, using 171 serum samples collected at two post-vaccination timepoints. Five antibody features were examined by P230Compete including total IgG (reported as ELISA units, EUF), IgG subclasses (IgG1F, IgG3F, IgG4F), and bound complement factor C1q (C1qF). EUF and IgG1F demonstrated strong correlation and excellent prediction of TRA≥80% in logistic regression analysis (AUC of 0.81 for both assays post-dose 3, and 0.80 and 0.76 post-dose 4). Furthermore, combining EUF and IgG1F showed even better predictive performance at each timepoint. P230Compete offers a promising proxy assay to replace SMFA in late-stage Pfs230D1 trials.
Authors
Cristina A. Meehan, Matthew V. Cowles, Robert D. Morrison, Yuyan Yi, Jingwen Gu, Jen C.C. Hume, Mina P. Peyton, Issaka Sagara, Sara A. Healy, Jonathan P. Renn, Patrick E. Duffy
Abstract
Clonal haematopoiesis of indeterminate potential (CHIP) is the expansion of blood stem cells and progeny after somatic mutation. CHIP associates with increased cardiovascular disease (CVD) with inflammation from macrophages a proposed common effector. However, mouse CHIP studies are discordant for clonal expansion and inflammation. Similarly, directionality of association between CHIP and CVD remains debated. We investigated effects of three CHIP mutations on macrophage cytokines, clonal expansion and atherosclerosis in parallel. We find that Tet2 and Dnmt3a mutations increase cytokines and inflammasome activation in Tet2 but decrease in Dnmt3a. However, Jak2 mutant macrophages produced equivalent cytokine as wild-type. In mice, Tet2 mutants clonally expanded, but Dnmt3a and Jak2 mutants didn’t. Expansion was unaffected by systemic inflammation, while hyperlipidemia expanded Tet2-/- cells, but not mono-allelic mutants. Similarly, human Mendelian randomisation showed no effect of serum cytokines or CVD on CHIP risk. Experimental atherosclerosis was increased in females with Tet2 and males with Jak2, but unchanged with Dnmt3a mutations. Together, common CHIP mutations have disparate effects on macrophage cytokines and clonal expansion, and sex-dependent effects on atherogenesis, suggesting a common mechanism across CHIP is unlikely. Thus, CHIP mutations differ in pathophysiology and clinical sequalae across sexes and should be treated as different entities.
Authors
Paul R. Carter, Lauren Kitt, Amanda Rodgers, Nichola Figg, Ang Zhou, Chengrui Zhu, Ziyang Wang, Peter Libby, Stephen Burgess, George S. Vassiliou, Murray CH. Clarke
Abstract
Hofbauer cells (HBC) are fetal-derived macrophages located in the placenta that contribute to antimicrobial defense, angiogenesis, tissue remodeling, and metabolic processes within the chorionic villi. Although their roles in placental biology are increasingly recognized, the mechanisms that regulate HBC identity and function are not yet fully defined. This study aimed to define the core transcriptomic and epigenomic features of HBCs in term placentas and to examine their capacity for transcriptional responsiveness and phenotypic variation. Using chromatin accessibility profiling and bulk RNA sequencing, we found that HBCs exhibit a unique gene expression and chromatin accessibility profile compared to other fetal and adult macrophages. We identified a coordinated transcriptional network involving nuclear receptors NR4A1–3, the glucocorticoid receptor (GR), and RFX family members (RFX1, RFX2, RFX5) that appears to shape HBC identity, particularly through pathways linked to lipid metabolism and angiogenesis. Although exploratory in nature, in vitro stimulation studies showed that HBCs exhibited increased transcriptional activity in response to combined IL-4 and RSG treatment, including induction of the lipid transporter CD36. Mass cytometry analysis revealed surface markers indicative of both immature and mature macrophage states. Together, these results indicated that HBCs represent a distinct and diverse macrophage population with specialized and adaptable regulatory program in the human placenta.
Authors
Benjámin R. Baráth, Dóra Bojcsuk, Krisztian Bene, Noemí Caballero-Sánchez, Tímea Cseh, João CR. de Freitas, Petros Tzerpos, Marta Toth, Zhonghua Tang, Seth Guller, Zoárd Tibor Krasznai, Patrícia Neuperger, Gabor J. Szebeni, Gergely Nagy, Tamás Deli, Laszlo Nagy
Abstract
Mucosal secretory IgA (sIgA) plays a central role in protecting against the invasion of respiratory pathogen via the upper respiratory tract. To understand how intranasal booster induces mucosal sIgA response in humans, we first used liquid chromatography-tandem mass spectrometry for peptide identification of immunoglobulin (MS Ig-Seq) and single-cell B-cell receptor sequencing (scBCR-seq) to identify mucosal spike-specific sIgA monoclonal antibodies (mAbs) after intranasal booster. These mucosal sIgA mAbs exhibited enhanced neutralization up to 100-fold against SARS-CoV-2 variants compared to their monomeric IgG and IgA isotypes. Deep sequencing and longitudinal analysis of B-cell receptor repertoires revealed that nasal booster re-stimulates memory B cells primed by intramuscularly vaccination to undergo IgA class switching, somatic hypermutation, and clonal expansion. Single-cell sequencing revealed that intranasal booster upregulated the expression of mucosal homing receptors in spike-specific IgA-expressing B cells. This increase coincided with a transient increase of cytokines and chemokines that facilitate B cell recruitment in the nasal mucosa. Our findings demonstrate that intranasal booster can be an effective strategy for inducing upper respiratory mucosal sIgA and establishing mucosal immune protection.
Authors
Si Chen, Zhengyuan Zhang, Zihan Lin, Li Yin, Lishan Ning, Wenming Liu, Qian Wang, Chenchen Yang, Bo Feng, Ying Feng, Yongping Wang, Hengchun Li, Ping He, Huan Liang, Yichu Liu, Zhixia Li, Bo Liu, Yang Li, Diana Boraschi, Linbing Qu, Xuefeng Niu, Nanshan Zhong, Pingchao Li, Ling Chen
Abstract
CD4+ T cells predominate lymphocytic foci found in the salivary glands (SGs) of Sjögren’s disease (SjD) cases. Yet little is known about T cell receptor (TCR) repertoire features that distinguish cases from healthy controls (HCs), the relationship between SG and peripheral blood (PB) repertoires of cases, and antigens recognized by pathogenic T cell clones. We performed deep sequencing of bulk-sorted CD4+CD45RA– PB T cells from SjD cases and matched HCs, and single-cell TCR sequencing of the same T cell population from labial SG biopsies of these cases. We found that clonally expanded SG CD4+ T cells expressed complementarity-determining region 3 (CDR3) sequences that were also detected in multiple copies in the blood of the same individuals with SjD. SjD cases displayed a “private” and restricted PB TCR repertoire with reduced clonotype diversity. We identified SjD-associated TCR motifs with the same putative antigen specificity shared between SGs and PB of cases. Their abundances in PB correlated with reduced salivary flow, linking these T cells with pathogenic disease features. Finally, we discovered 2 Ro60 epitopes eliciting an HLA-restricted immune response from expanded SG T cell clones. The comprehensive characterization of SjD TCR repertoires enables the discovery of target antigens and therapeutic strategies.
Authors
Ananth Aditya Jupudi, Michelle L. Joachims, Christina Lawrence, Charmaine Lopez-Davis, Bhuwan Khatri, Astrid Rasmussen, Kiely Grundahl, R. Hal Scofield, Judith A. James, Joel M. Guthridge, Christopher J. Lessard, Linda F. Thompson, A. Darise Farris
Abstract
Cardiac arrhythmias increase during acute SARS-CoV-2 infection and in long COVID syndrome, by unknown mechanisms. This study explored the acute and long-term effects of COVID-19 on cardiac electrophysiology and the cardiac conduction system (CCS) in a hamster model. Electrocardiograms and subpleural pressures were recorded by telemetry for 4 weeks after SARS-CoV-2 infection, and interferon-stimulated gene expression and macrophage infiltration of the CCS were assessed at 4 days and 4 weeks postinfection. COVID-19 induced pronounced tachypnea and cardiac arrhythmias, including bradycardia and persistent atrioventricular block, though no viral protein expression was detected in the heart. Arrhythmias developed rapidly, partially reversed, and then redeveloped, indicating persistent CCS injury. COVID-19 induced cardiac cytokine expression, connexin mislocalization, and CCS macrophage remodeling. Interestingly, sterile innate immune activation by direct cardiac injection of polyinosinic:polycytidylic acid (PIC) induced arrhythmias similar to those of COVID-19. PIC strongly induced cytokine secretion and interferon signaling in hearts, human induced pluripotent stem cell–derived cardiomyocytes, and engineered heart tissues, accompanied by alterations in excitation-contraction coupling. Importantly, the pulmonary and cardiac effects of COVID-19 were blunted by JAK/STAT inhibition or a mitochondrially targeted antioxidant, indicating that SARS-CoV-2 infection indirectly leads to arrhythmias by innate immune activation and redox stress, which could have implications for long COVID syndrome.
Authors
Deepthi Ashok, Ting Liu, Misato Nakanishi-Koakutsu, Joseph Criscione, Meghana Prakash, Alexis Tensfeldt, Byunggik Kim, Bryan Ho, Julian Chow, Morgan Craney, Mark J. Ranek, Brian L. Lin, Kyriakos Papanicolaou, Agnieszka Sidor, D. Brian Foster, Hee Cheol Cho, Andrew Pekosz, Jason Villano, Deok-Ho Kim, Brian O’Rourke
Abstract
The transcription factor IKAROS, encoded by IKZF1, is crucial for lymphocyte development and differentiation. Germline heterozygous IKZF1 mutations cause B cell immunodeficiency, but also affect T cells. Patients with IKZF1 haploinsufficiency (HI) or dimerization-defective (DD) variants show reduced naive and increased memory T cells, while dominant-negative (DN) mutations result in the opposite phenotype. Gain-of-function patients display variable patterns. To investigate IKAROS’s role in shaping the human naive/memory T cell phenotype, we performed IKAROS immunomodulation and knockdown experiments and analyzed early T cell development in an artificial thymic organoid (ATO) system using CD34+ cells from patients with representative IKZF1 variants. IKAROS inhibition by lenalidomide or silencing by small hairpin RNA directly altered expression of HNRNPLL, the master regulator of CD45 isoform splicing that defines CD45RA+/naive and CD45RO+/memory phenotypes. In the ATO system, IKAROS-DN precursor cells were blocked at the CD4–CD8–/double-negative stage and retained a CD45RA+ phenotype, whereas IKAROS-HI cells inefficiently reached the CD4+CD8+/double-positive stage and partially transitioned from CD45RA to CD45RO. Analysis of public gene expression data showed high HNRNPLL expression in double-positive thymic cells, beyond the stages affected by IKZF1 DN and HI mutations. Collectively, these findings indicate that IKAROS regulates early and late T cell development by mechanisms, including HNRNPLL modulation.
Authors
Jennifer Stoddard, Hye Sun Kuehn, Ravichandra Tagirasa, Marita Bosticardo, Francesca Pala, Julie E. Niemela, Agustin A. Gil Silva, Kayla Amini, Eduardo Anaya, Mario Framil Seoane, Carolina Bouso, Dimana Dimitrova, Jennifer A. Kanakry, Laia Alsina, Matias Oleastro, Steven M. Holland, Thomas A. Fleisher, Richard L. Wasserman, Luigi D. Notarangelo, Sergio D. Rosenzweig
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