RÉSUMÉ
Rheumatoid arthritis (RA) is a systemic immune-mediated disease characterized by joint inflammation and destruction. The disease typically affects small joints in the hands and feet, later progressing to involve larger joints such as the knees, shoulders, and hips. While the reasons for these joint-specific differences are unclear, distinct epigenetic patterns associated with joint location have been reported. In this study, we evaluated the unique epigenetic landscapes of fibroblast-like synoviocytes (FLS) from hip and knee synovium in RA patients, focusing on the expression and regulation of Homeobox (HOX) transcription factors. These highly conserved genes play a critical role in embryonic development and are known to maintain distinct expression patterns in various adult tissues. We found that several HOX genes, especially HOXD10, were differentially expressed in knee FLS compared with hip FLS. Epigenetic differences in chromatin accessibility and histone marks were observed in HOXD10 promoter between knee and hip FLS. Histone modification, particularly histone acetylation, was identified as an important regulator of HOXD10 expression. To understand the mechanism of differential HOXD10 expression, we inhibited histone deacetylases (HDACs) with small molecules and siRNA. We found that HDAC1 blockade or deficiency normalized the joint-specific HOXD10 expression patterns. These observations suggest that epigenetic differences, specifically histone acetylation related to increased HDAC1 expression, play a crucial role in joint-specific HOXD10 expression. Understanding these mechanisms could provide insights into the regional aspects of RA and potentially lead to therapeutic strategies targeting specific patterns of joint involvement during the course of disease.
Sujet(s)
Polyarthrite rhumatoïde , Épigenèse génétique , Fibroblastes , Protéines à homéodomaine , Cellules synoviales , Humains , Polyarthrite rhumatoïde/métabolisme , Polyarthrite rhumatoïde/anatomopathologie , Polyarthrite rhumatoïde/génétique , Protéines à homéodomaine/génétique , Protéines à homéodomaine/métabolisme , Cellules synoviales/métabolisme , Cellules synoviales/anatomopathologie , Fibroblastes/métabolisme , Fibroblastes/anatomopathologie , Facteurs de transcription/génétique , Facteurs de transcription/métabolisme , Histone Deacetylase 1/métabolisme , Histone Deacetylase 1/génétique , Régions promotrices (génétique) , Articulation du genou/anatomopathologie , Articulation du genou/métabolisme , Régulation de l'expression des gènes , Histone/métabolisme , Acétylation , Articulation de la hanche/anatomopathologie , Articulation de la hanche/métabolismeRÉSUMÉ
Rheumatoid arthritis (RA) is an autoimmune disease involving antigen-specific T and B cells. Here, we perform single-cell RNA and repertoire sequencing on paired synovial tissue and blood samples from 12 seropositive RA patients. We identify clonally expanded CD4 + T cells, including CCL5+ cells and T peripheral helper (Tph) cells, which show a prominent transcriptomic signature of recent activation and effector function. CD8 + T cells show higher oligoclonality than CD4 + T cells, with the largest synovial clones enriched in GZMK+ cells. CD8 + T cells with possibly virus-reactive TCRs are distributed across transcriptomic clusters. In the B cell compartment, NR4A1+ activated B cells, and plasma cells are enriched in the synovium and demonstrate substantial clonal expansion. We identify synovial plasma cells that share BCRs with synovial ABC, memory, and activated B cells. Receptor-ligand analysis predicted IFNG and TNFRSF members as mediators of synovial Tph-B cell interactions. Together, these results reveal clonal relationships between functionally distinct lymphocyte populations that infiltrate the synovium of patients with RA.
Sujet(s)
Polyarthrite rhumatoïde , Lymphocytes B , Membrane synoviale , Humains , Polyarthrite rhumatoïde/immunologie , Polyarthrite rhumatoïde/métabolisme , Polyarthrite rhumatoïde/génétique , Polyarthrite rhumatoïde/anatomopathologie , Membrane synoviale/immunologie , Membrane synoviale/métabolisme , Lymphocytes B/immunologie , Lymphocytes B/métabolisme , Femelle , Mâle , Adulte d'âge moyen , Lymphocytes T CD8+/immunologie , Lymphocytes T CD8+/métabolisme , Sous-populations de lymphocytes/immunologie , Sous-populations de lymphocytes/métabolisme , Lymphocytes T CD4+/immunologie , Lymphocytes T CD4+/métabolisme , Analyse sur cellule unique , Transcriptome , Plasmocytes/immunologie , Plasmocytes/métabolisme , Sujet âgé , Activation des lymphocytes , AdulteRÉSUMÉ
The mechanisms responsible for the distribution and severity of joint involvement in rheumatoid arthritis (RA) are not known. To explore whether site-specific fibroblast-like synoviocyte (FLS) biology might be associated with location-specific synovitis and explain the predilection for hand (wrist/metacarpal phalangeal joints) involvement in RA, we generated transcriptomic and chromatin accessibility data from FLS to identify the transcription factors and pathways. Networks were constructed by integration of chromatin accessibility and gene expression data. Analysis revealed joint-specific patterns of FLS phenotype, with proliferative, migratory, proinflammatory, and matrix-degrading characteristics observed in resting FLS derived from the hand joints compared with hip or knee. TNF stimulation amplified these differences, with greater enrichment of proinflammatory and proliferative genes in hand FLS compared with hip and knee FLS. Hand FLS also had the greatest expression of markers associated with an "activated" state relative to the "resting" state, with the greatest cytokine and MMP expression in TNF-stimulated hand FLS. Predicted differences in proliferation and migration were biologically validated with hand FLS exhibiting greater migration and cell growth than hip or knee FLS. Distinctive joint-specific FLS biology associated with a more aggressive inflammatory response might contribute to the distribution and severity of joint involvement in RA.
Sujet(s)
Polyarthrite rhumatoïde , Chromatine , Fibroblastes , Cellules synoviales , Polyarthrite rhumatoïde/anatomopathologie , Polyarthrite rhumatoïde/métabolisme , Polyarthrite rhumatoïde/génétique , Humains , Cellules synoviales/métabolisme , Cellules synoviales/anatomopathologie , Fibroblastes/métabolisme , Fibroblastes/anatomopathologie , Chromatine/métabolisme , Prolifération cellulaire/génétique , Mouvement cellulaire/génétique , TranscriptomeRÉSUMÉ
OBJECTIVE: Rheumatoid arthritis (RA) is an autoimmune disease in which the joint lining or synovium becomes highly inflamed and majorly contributes to disease progression. Understanding pathogenic processes in RA synovium is critical for identifying therapeutic targets. We performed laser capture microscopy (LCM) followed by RNA sequencing (LCM-RNAseq) to study regional transcriptomes throughout RA synovium. METHODS: Synovial lining, sublining, and vessel samples were captured by LCM from seven patients with RA and seven patients with osteoarthritis (OA). RNAseq was performed on RNA extracted from captured tissue. Principal component analysis was performed on the sample set by disease state. Differential expression analysis was performed between disease states based on log2 fold change and q value parameters. Pathway analysis was performed using the Reactome Pathway Database on differentially expressed genes among disease states. Significantly enriched pathways in each synovial region were selected based on the false discovery rate. RESULTS: RA and OA transcriptomes were distinguishable by principal component analysis. Pairwise comparisons of synovial lining, sublining, and vessel samples between RA and OA revealed substantial differences in transcriptional patterns throughout the synovium. Hierarchical clustering of pathways based on significance revealed a pattern of association between biologic function and synovial topology. Analysis of pathways uniquely enriched in each region revealed distinct phenotypic abnormalities. As examples, RA lining samples were marked by anomalous immune cell signaling, RA sublining samples were marked by aberrant cell cycle, and RA vessel samples were marked by alterations in heme scavenging. CONCLUSION: LCM-RNAseq confirms reported transcriptional differences between the RA synovium and the OA synovium and provides evidence supporting a relationship between synovial topology and molecular anomalies in RA.
Sujet(s)
Polyarthrite rhumatoïde , Microdissection au laser , Analyse de séquence d'ARN , Membrane synoviale , Humains , Polyarthrite rhumatoïde/génétique , Polyarthrite rhumatoïde/anatomopathologie , Membrane synoviale/anatomopathologie , Membrane synoviale/métabolisme , Femelle , Mâle , Adulte d'âge moyen , Transcriptome , Sujet âgé , Arthrose/génétique , Arthrose/anatomopathologie , Analyse en composantes principales , Analyse de profil d'expression de gènesRÉSUMÉ
OBJECTIVE: Fibroblast-like synoviocytes (FLS) contribute to the pathogenesis of rheumatoid arthritis (RA), in part due to activation of the proinflammatory transcription factor NF-κB. Neddylation is modulated by the negative regulator of ubiquitin-like protein (NUB) 1. We determined whether NUB1 and neddylation are aberrant in the models with RA FLS, thereby contributing to their aggressive phenotype. METHODS: Models with RA or osteoarthritis (OA) FLS were obtained from arthroplasty synovia. Real-time quantitative polymerase chain reaction and Western blot analysis assessed gene and protein expression, respectively. NUB1 was overexpressed using an expression vector. NF-κB activation was assessed by stimulating FLS with interleukin (IL)-1ß. Neddylation inhibitor (MLN4924) and proteasome inhibitor were used in migration and gene expression assays. MLN4924 was used in the model with K/BxN serum-transfer arthritis. RESULTS: Enhanced H3K27ac and H3K27me3 peaks were observed in the NUB1 promoter in the OA FLS compared with the RA FLS. NUB1 was constitutively expressed by FLS, but induction by IL-1ß was significantly greater in the OA FLS. The ratio of neddylated cullin (CUL) 1 to nonneddylated CUL1 was lower in the OA FLS than the RA FLS. NUB1 overexpression decreased NF-κB nuclear translocation and IL-6 messenger RNA (mRNA) in IL-1ß-stimulated the RA FLS. MLN4924 decreased CUL1 neddylation, NF-κB nuclear translocation, and IL-6 mRNA in IL-1ß-stimulated the RA FLS. MLN4924 significantly decreased arthritis severity in the model with K/BxN serum-transfer arthritis. CONCLUSION: CUL1 neddylation and NUB1 induction is dysregulated in the models with RA, which increases FLS activation. Inhibition of neddylation is an effective therapy in an animal model of arthritis. These data suggest that the neddylation system contributes to the pathogenesis of RA and that regulation of neddylation could be a novel therapeutic approach.
Sujet(s)
Polyarthrite rhumatoïde , Cyclopentanes , Fibroblastes , Facteur de transcription NF-kappa B , Cellules synoviales , Polyarthrite rhumatoïde/métabolisme , Cellules synoviales/métabolisme , Cellules synoviales/effets des médicaments et des substances chimiques , Humains , Cyclopentanes/pharmacologie , Fibroblastes/métabolisme , Fibroblastes/effets des médicaments et des substances chimiques , Facteur de transcription NF-kappa B/métabolisme , Arthrose/métabolisme , Interleukine-1 bêta/métabolisme , Interleukine-1 bêta/pharmacologie , Pyrimidines/pharmacologie , Animaux , Ubiquitines/métabolisme , Ubiquitines/génétique , Inflammation/métabolisme , Cullines/métabolisme , Cullines/génétique , Protéine NEDD8/métabolisme , Protéine NEDD8/génétique , SourisRÉSUMÉ
OBJECTIVE: To define the relationship between chronic chikungunya post-viral arthritis disease severity, cytokine response and T cell subsets in order to identify potential targets for therapy. METHODS: Participants with chikungunya arthritis were recruited from Colombia from 2019-2021. Arthritis disease severity was quantified using the Disease Activity Score-28 and an Arthritis-Flare Questionnaire adapted for chikungunya arthritis. Plasma cytokine concentrations (interleukin (IL)-1ß, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, interferon-γ and tumor necrosis factor (TNF)) were measured using a Meso Scale Diagnostics assay. Peripheral blood T cell subsets were measured using flow cytometry. RESULTS: Among participants with chikungunya arthritis (N = 158), IL-2 levels and frequency of regulatory T cells (Tregs) were low. Increased arthritis disease activity was associated with higher levels of inflammatory cytokines (IL-6, TNF and CRP) and immunoregulatory cytokine IL-10 (p<0.05). Increased arthritis flare activity was associated with higher Treg frequencies (p<0.05) without affecting T effector (Teff) frequencies, Treg/Teff ratios and Treg subsets. Finally, elevated levels of IL-2 were correlated with increased Treg frequency, percent Tregs out of CD4+ T cells, and Treg subsets expressing immunosuppressive markers, while also correlating with an increased percent Teff out of live lymphocytes (p<0.05). CONCLUSION: Chikungunya arthritis is characterized by increased inflammatory cytokines and deficient IL-2 and Treg responses. Greater levels of IL-2 were associated with improved Treg numbers and immunosuppressive markers. Future research may consider targeting these pathways for therapy.
Sujet(s)
Arthrite infectieuse , Fièvre chikungunya , Humains , Cytokines/métabolisme , Interleukine-10/métabolisme , Études transversales , Interleukine-2/métabolisme , Interleukine-6/métabolisme , Fièvre chikungunya/complications , Lymphocytes T régulateurs/métabolisme , Lymphocytes T CD4+/métabolisme , Facteur de nécrose tumorale alpha/métabolisme , ImmunosuppresseursRÉSUMÉ
The mechanisms responsible for the distribution and severity of joint involvement in rheumatoid arthritis (RA) are not known. To explore whether site-specific FLS biology might be associated with location-specific synovitis and explain the predilection for hand (wrist/metacarpal phalangeal joints) involvement in RA, we generated transcriptomic and chromatin accessibility data from FLS to identify the transcription factors (TFs) and pathways. Networks were constructed by integration of chromatin accessibility and gene expression data. Analysis revealed joint-specific patterns of FLS phenotype, with proliferative, migratory, proinflammatory, and matrix-degrading characteristics observed in resting FLS derived from the hand joints compared with hip or knee. TNF-stimulation amplified these differences, with greater enrichment of proinflammatory and proliferative genes in hand FLS compared with hip and knee FLS. Hand FLS also had the greatest expression of markers associated with an 'activated' state relative to the 'resting' state, with the greatest cytokine and MMP expression in TNF-stimulated hand FLS. Predicted differences in proliferation and migration were biologically validated with hand FLS exhibiting greater migration and cell growth than hip or knee FLS. Distinctive joint-specific FLS biology associated with a more aggressive inflammatory response might contribute to the distribution and severity of joint involvement in RA.
RÉSUMÉ
Rheumatoid arthritis is a prototypical autoimmune disease that causes joint inflammation and destruction1. There is currently no cure for rheumatoid arthritis, and the effectiveness of treatments varies across patients, suggesting an undefined pathogenic diversity1,2. Here, to deconstruct the cell states and pathways that characterize this pathogenic heterogeneity, we profiled the full spectrum of cells in inflamed synovium from patients with rheumatoid arthritis. We used multi-modal single-cell RNA-sequencing and surface protein data coupled with histology of synovial tissue from 79 donors to build single-cell atlas of rheumatoid arthritis synovial tissue that includes more than 314,000 cells. We stratified tissues into six groups, referred to as cell-type abundance phenotypes (CTAPs), each characterized by selectively enriched cell states. These CTAPs demonstrate the diversity of synovial inflammation in rheumatoid arthritis, ranging from samples enriched for T and B cells to those largely lacking lymphocytes. Disease-relevant cell states, cytokines, risk genes, histology and serology metrics are associated with particular CTAPs. CTAPs are dynamic and can predict treatment response, highlighting the clinical utility of classifying rheumatoid arthritis synovial phenotypes. This comprehensive atlas and molecular, tissue-based stratification of rheumatoid arthritis synovial tissue reveal new insights into rheumatoid arthritis pathology and heterogeneity that could inform novel targeted treatments.
Sujet(s)
Polyarthrite rhumatoïde , Humains , Polyarthrite rhumatoïde/complications , Polyarthrite rhumatoïde/génétique , Polyarthrite rhumatoïde/immunologie , Polyarthrite rhumatoïde/anatomopathologie , Cytokines/métabolisme , Inflammation/complications , Inflammation/génétique , Inflammation/immunologie , Inflammation/anatomopathologie , Membrane synoviale/anatomopathologie , Lymphocytes T/immunologie , Lymphocytes B/immunologie , Prédisposition génétique à une maladie/génétique , Phénotype , Analyse de l'expression du gène de la cellule uniqueRÉSUMÉ
Molecular markers of autoimmunity, such as antibodies to citrullinated protein antigens (ACPA), are detectable prior to inflammatory arthritis (IA) in rheumatoid arthritis (RA) and may define a state that is 'at-risk' for future RA. Here we present a cross-sectional comparative analysis among three groups that include ACPA positive individuals without IA (At-Risk), ACPA negative individuals and individuals with early, ACPA positive clinical RA (Early RA). Differential methylation analysis among the groups identifies non-specific dysregulation in peripheral B, memory and naïve T cells in At-Risk participants, with more specific immunological pathway abnormalities in Early RA. Tetramer studies show increased abundance of T cells recognizing citrullinated (cit) epitopes in At-Risk participants, including expansion of T cells reactive to citrullinated cartilage intermediate layer protein I (cit-CILP); these T cells have Th1, Th17, and T stem cell memory-like phenotypes. Antibody-antigen array analyses show that antibodies targeting cit-clusterin, cit-fibrinogen and cit-histone H4 are elevated in At-Risk and Early RA participants, with the highest levels of antibodies detected in those with Early RA. These findings indicate that an ACPA positive at-risk state is associated with multifaceted immune dysregulation that may represent a potential opportunity for targeted intervention.
Sujet(s)
Polyarthrite rhumatoïde , Autoanticorps , Humains , Études transversales , ÉpitopesRÉSUMÉ
The ACT Network was funded by NIH to provide investigators from across the Clinical and Translational Science Award (CTSA) Consortium the ability to directly query national federated electronic health record (EHR) data for cohort discovery and feasibility assessment of multi-site studies. NIH refunded the program for expanded research application to become "Evolve to Next-Gen ACT" (ENACT). In parallel, the US Food and Drug Administration has been evaluating the use of real-world data (RWD), including EHR data, as sources of real-world evidence (RWE) for its regulatory decisions involving drug and biological products. Using insights from implementation science, six lessons learned from ACT for developing and sustaining RWD/RWE infrastructures and networks across the CTSA Consortium are presented in order to inform ENACT's development from the outset. Lessons include intentional institutional relationship management, end-user engagement, beta-testing, and customer-driven adaptation. The ENACT team is also conducting customer discovery interviews with CTSA hub and investigators using Innovation-Corps@NCATS (I-Corps™) methodology for biomedical entrepreneurs to uncover unmet RWD needs. Possible ENACT value proposition hypotheses are presented by stage of research. Developing evidence about methods for sustaining academically derived data infrastructures and support can advance the science of translation and support our nation's RWD/RWE research capacity.
RÉSUMÉ
BACKGROUND: Antibodies to citrullinated protein antigens have been linked to altered left ventricular (LV) structure and function in patients with rheumatoid arthritis (RA). Serum reactivity to several citrullinated protein/peptide antigens has been identified in RA, which are detectable years before RA onset and in individuals who may never develop RA. Among community-living individuals without heart failure (HF) at baseline in the Multi-Ethnic Study of Atherosclerosis (MESA), we investigated associations between serum reactivity to citrullinated protein/peptide antigens, LV mass, LV ejection fraction (LVEF), and incident HF. METHODS: Among 1232 MESA participants, we measured serum reactivity to 28 different citrullinated proteins/peptides using a multiplex bead-based array. Each antibody was defined as having extremely high reactivity (EHR) if >95th percentile cut-off in MESA. Number of EHR antibody responses to citrullinated protein/peptide antigens were summed for each participant (range 0-28). LV mass(g) and LVEF(%) were measured on cardiac MRI. Associations between EHR antibodies and LV mass and LVEF were evaluated using linear regression. Cox proportional hazards models were used to evaluate associations between EHR antibodies and incident HF during 11 years of follow-up, adjusting for age, gender, race/ethnicity, smoking status, systolic blood pressure, use of anti-hypertensive medications, self-reported arthritis, IL-6, body surface area, and estimated glomerular filtration rate. RESULTS: Mean age was 65±10, 50% were female, 40% were White, 21% were Black, 26% were Hispanic/Latino, and 14% were Chinese. Twenty-seven percent of MESA participants had extremely high reactivity to ≥ 1 citrullinated protein/peptide antigen. In fully adjusted analysis, every additional EHR antibody was significantly associated with 0.1% lower LVEF (95% CI: -0.17%, -0.02%). No association was observed with LV mass (ß per additional EHR antibody) = 0.13±0.15 (p = 0.37)). Neither the presence nor number of EHR antibodies was associated with incident HF during follow-up (HR per additional EHR antibody = 1.008 (95% CI: 0.97, 1.05)). CONCLUSION: Greater number of extremely highly reactive antibodies was associated with lower LVEF, but not with LV mass or incident HF. Thus, serum reactivity to citrullinated protein/peptide antigens was associated with subtle subclinical changes in myocardial contractility, but the significance in relation to clinically apparent HF is uncertain.
Sujet(s)
Polyarthrite rhumatoïde , Athérosclérose , Défaillance cardiaque , Humains , Femelle , Adulte d'âge moyen , Sujet âgé , Mâle , Peptides , Modèles des risques proportionnels , Imagerie par résonance magnétique , Fonction ventriculaire gaucheRÉSUMÉ
Background: Recruitment of study participants is challenging and can incur significant costs. Social media advertising is a promising method for recruiting clinical studies and may improve cost efficiency by targeting populations likely to match a study's qualifications. Prior systematic reviews of social media as a recruitment tool have been favourable, however, there are no meta-analyses of its cost-effectiveness. Methods: Studies evaluating recruitment costs through social media and non-social media methods were identified on MEDLINE and EMBASE. Articles were screened through a two-step process in accordance with PRISMA guidelines. Cost data were extracted from selected articles and meta-analyzed using the Mantel-Haenszel method. The primary outcome was the relative cost-effectiveness of social media compared to non-social media recruitment, defined as the odds ratio of recruiting a participant per US dollar spent. The secondary outcome was the cost-effectiveness of social media recruitment compared to other online recruitment methods only. Results: In total, 23 studies were included in the meta-analysis. The odds ratio of recruiting a participant through social media advertising compared to non-social media methods per dollar spent was 1.97 [95% CI 1.24-3.00, P = 0.004]. The odds ratio of recruiting a participant through social media compared to other online methods only was 1.66 [95% CI 1.02-2.72, P = 0.04]. Conclusions: Social media advertising may be more cost-effective than other methods of recruitment, however, the magnitude of cost-effectiveness is highly variable between studies. There are limited data on newer social media platforms and on difficult-to-reach populations such as non-English speakers or older individuals.
RÉSUMÉ
Rheumatoid arthritis (RA) is a systemic autoimmune disease with currently no universally highly effective prevention strategies. Identifying pathogenic immune phenotypes in 'At-Risk' populations prior to clinical disease onset is crucial to establishing effective prevention strategies. Here, we applied mass cytometry to deeply characterize the immunophenotypes in blood from At-Risk individuals identified through the presence of serum antibodies to citrullinated protein antigens (ACPA) and/or first-degree relative (FDR) status (n=52), as compared to established RA (n=67), and healthy controls (n=48). We identified significant cell expansions in At-Risk individuals compared with controls, including CCR2+CD4+ T cells, T peripheral helper (Tph) cells, type 1 T helper cells, and CXCR5+CD8+ T cells. We also found that CD15+ classical monocytes were specifically expanded in ACPA-negative FDRs, and an activated PAX5 low naïve B cell population was expanded in ACPA-positive FDRs. Further, we developed an "RA immunophenotype score" classification method based on the degree of enrichment of cell states relevant to established RA patients. This score significantly distinguished At-Risk individuals from controls. In all, we systematically identified activated lymphocyte phenotypes in At-Risk individuals, along with immunophenotypic differences among both ACPA+ and ACPA-FDR At-Risk subpopulations. Our classification model provides a promising approach for understanding RA pathogenesis with the goal to further improve prevention strategies and identify novel therapeutic targets.
RÉSUMÉ
Rheumatoid arthritis (RA) is an autoimmune disease initiated by antigen-specific T cells and B cells, which promote synovial inflammation through a complex set of interactions with innate immune and stromal cells. To better understand the phenotypes and clonal relationships of synovial T and B cells, we performed single-cell RNA and repertoire sequencing on paired synovial tissue and peripheral blood samples from 12 donors with seropositive RA ranging from early to chronic disease. Paired transcriptomic-repertoire analyses highlighted 3 clonally distinct CD4 T cells populations that were enriched in RA synovium: T peripheral helper (Tph) and T follicular helper (Tfh) cells, CCL5+ T cells, and T regulatory cells (Tregs). Among these cells, Tph cells showed a unique transcriptomic signature of recent T cell receptor (TCR) activation, and clonally expanded Tph cells expressed an elevated transcriptomic effector signature compared to non-expanded Tph cells. CD8 T cells showed higher oligoclonality than CD4 T cells, and the largest CD8 T cell clones in synovium were highly enriched in GZMK+ cells. TCR analyses revealed CD8 T cells with likely viral-reactive TCRs distributed across transcriptomic clusters and definitively identified MAIT cells in synovium, which showed transcriptomic features of TCR activation. Among B cells, non-naive B cells including age-associated B cells (ABC), NR4A1+ activated B cells, and plasma cells, were enriched in synovium and had higher somatic hypermutation rates compared to blood B cells. Synovial B cells demonstrated substantial clonal expansion, with ABC, memory, and activated B cells clonally linked to synovial plasma cells. Together, these results reveal clonal relationships between functionally distinct lymphocyte populations that infiltrate RA synovium.
RÉSUMÉ
Significant recent progress in understanding rheumatoid arthritis (RA) pathogenesis has led to improved treatment and quality of life. The introduction of targeted-biologic and -synthetic disease modifying anti-rheumatic drugs (DMARDs) has also transformed clinical outcomes. Despite this, RA remains a life-long disease without a cure. Unmet needs include partial response and non-response to treatment in many patients, failure to achieve immune homeostasis or drug free remission, and inability to repair damaged tissues. RA is now recognized as the end of a multi-year prodromal phase in which systemic immune dysregulation, likely beginning in mucosal surfaces, is followed by a symptomatic clinical phase. Inflammation and immune reactivity are primarily localized to the synovium leading to pain and articular damage, but is also associated with a broader series of comorbidities. Here, we review recently described immunologic mechanisms that drive breach of tolerance, chronic synovitis, and remission.
Sujet(s)
Antirhumatismaux , Polyarthrite rhumatoïde , Synovite , Humains , Qualité de vie , Polyarthrite rhumatoïde/traitement médicamenteux , Antirhumatismaux/usage thérapeutique , Membrane synovialeRÉSUMÉ
In seropositive rheumatoid arthritis (RA), the onset of clinically apparent inflammatory arthritis (IA) is typically preceded by a prolonged period of autoimmunity manifest by the presence of circulating autoantibodies that can include antibodies to citrullinated protein antigens (ACPA) and rheumatoid factor (RF). This period prior to clinical IA can be designated preclinical RA in those individuals who have progressed to a clinical diagnosis of RA, and an 'at-risk' status in those who have not developed IA but exhibit predictive biomarkers of future clinical RA. With the goal of developing RA prevention strategies, studies have characterized immune phenotypes of preclinical RA/at-risk states. From these studies, a model has emerged wherein mucosal inflammation and dysbiosis may lead first to local autoantibody production that should normally be transient, but instead is followed by systemic spread of the autoimmunity as manifest by serum autoantibody elevations, and ultimately drives the development of clinically identified joint inflammation. This model can be envisioned as the progression of disease development through serial 'checkpoints' that in principle should constrain or resolve autoimmunity; however, instead the checkpoints 'fail' and clinical RA develops. Herein we review the immune processes that are likely to be present at each step and the potential therapeutic strategies that could be envisioned to delay, diminish, halt or even reverse the progression to clinical RA. Notably, these prevention strategies could utilize existing therapies approved for clinical RA, therapies approved for other diseases that target relevant pathways in the preclinical/at-risk state, or approaches that target novel pathways.