Single-cell characterisation of tissue homing CD4 + and CD8 + T cell clones in immune-mediated refractory arthritis.

BACKGROUND: Immune-mediated arthritis is a group of autoinflammatory diseases, where the patient's own immune system attacks and destroys synovial joints. Sustained remission is not always achieved with available immunosuppressive treatments, warranting more detailed studies of T cell responses that perpetuate synovial inflammation in treatment-refractory patients. METHODS: In this study, we investigated CD4 + and CD8 + T lymphocytes from the synovial tissue and peripheral blood of patients with treatment-resistant immune-mediated arthritis using paired single-cell RNA and TCR-sequencing. To gain insights into the trafficking of clonal families, we compared the phenotypes of clones with the exact same TCRß amino acid sequence between the two tissues. RESULTS: Our results show that both CD4 + and CD8 + T cells display a more activated and inflamed phenotype in the synovial tissue compared to peripheral blood both at the population level and within individual T cell families. Furthermore, we found that both cell subtypes exhibited clonal expansion in the synovial tissue. CONCLUSIONS: Our findings suggest that the local environment in the synovium drives the proliferation of activated cytotoxic T cells, and both CD4 + and CD8 + T cells may contribute to tissue destruction and disease pathogenesis.

Patterns of reproductive health in inflammatory rheumatic diseases and other immune-mediated diseases: a nationwide registry study.

OBJECTIVES: Rheumatic diseases may impair reproductive success and pregnancy outcomes, but systematic evaluations across diseases are lacking. We conducted a nationwide cohort study to examine the impact of rheumatic diseases on reproductive health measures, comparing the impacts with those of other immune-mediated diseases (IMDs). METHODS: Out of all of the 5 339 804 Finnish citizens, individuals born 1964-1984 and diagnosed with any of the 19 IMDs before age 30 (women) or 35 (men) were matched with 20 controls by birth year, sex, and education. We used data from nationwide health registers to study the impact of IMDs on reproductive health measures, such as reproductive success and, for women, ever having experienced adverse maternal and perinatal outcomes. RESULTS: Several of the rheumatic diseases, particularly SLE, JIA, and seropositive RA, were associated with higher rates of childlessness and fewer children. The risks for pre-eclampsia, newborns being small for gestational age, preterm delivery, non-elective Caesarean sections, and need of neonatal intensive care were increased in many IMDs. Particularly, SLE, SS, type 1 diabetes, and Addison's disease showed >2-fold risks for some of these outcomes. In most rheumatic diseases, moderate (1.1-1.5-fold) risk increases were observed for diverse adverse pregnancy outcomes, with similar effects in IBD, celiac disease, asthma, ITP, and psoriasis. CONCLUSION: Rheumatic diseases have a broad impact on reproductive health, with effects comparable with that of several other IMDs. Of the rheumatic diseases, SLE and SS conferred the largest risk increases on perinatal adverse event outcomes.

Extracellular vesicles from Aggregatibacter actinomycetemcomitans exhibit potential antitumorigenic effects in oral cancer: a comparative in vitro study.

Aggregatibacter actinomycetemcomitans is an opportunistic Gram-negative periodontopathogen strongly associated with periodontitis and infective endocarditis. Recent evidence suggests that periodontopathogens can influence the initiation and progression of oral squamous cell carcinoma (OSCC). Herein we aimed to investigate the effect of A. actinomycetemcomitans-derived extracellular vesicles (EVs) on OSCC cell behavior compared with EVs from periodontopathogens known to associate with carcinogenesis. EVs were isolated from: A. actinomycetemcomitans and its mutant strains lacking the cytolethal distending toxin (CDT) or lipopolysaccharide (LPS) O-antigen; Porphyromonas gingivalis; Fusobacterium nucleatum; and Parvimonas micra. The effect of EVs on primary and metastatic OSCC cells was assessed using cell proliferation, apoptosis, migration, invasion, and tubulogenesis assays. A. actinomycetemcomitans-derived EVs reduced the metastatic cancer cell proliferation, invasion, tubulogenesis, and increased apoptosis, mostly in CDT- and LPS O-antigen-dependent manner. EVs from F. nucleatum impaired the metastatic cancer cell proliferation and induced the apoptosis rates in all OSCC cell lines. EVs enhanced cancer cell migration regardless of bacterial species. In sum, this is the first study demonstrating the influence of A. actinomycetemcomitans-derived EVs on oral cancer in comparison with other periodontopathogens. Our findings revealed a potential antitumorigenic effect of these EVs on metastatic OSCC cells, which warrants further in vivo investigations.

Long-term follow up of families with pathogenic NFKB1 variants reveals incomplete penetrance and frequent inflammatory sequelae.

Nuclear factor κ light-chain enhancer of activated B cells (NF-κB) family of evolutionarily conserved transcription factors are involved in key cellular signaling pathways. Previously, hypogammaglobulinemia and common variable immunodeficiency (CVID)-like phenotypes have been associated with NFKB1 variants and loss-of-function NFKB1 variants have been reported as the most common monogenic cause for CVID among Europeans. Here, we describe a Finnish cohort of NFKB1 carriers consisting of 31 living subjects in six different families carrying five distinct heterozygous variants. In contrast to previous reports, the clinical penetrance was not complete even with advancing age and the prevalence of CVID/hypogammaglobulinemia was significantly lower, whereas (auto)inflammatory manifestations were more common (42% of the total cohort). At current stage of knowledge, routine genetic screening of asymptomatic individuals is not recommended, but counseling of potential adult carriers seems necessary.

Inflammation and Neutrophil Oxidative Burst in a Family with NFKB1 p.R157X LOF and Sterile Necrotizing Fasciitis.

Loss-of-function (LOF) mutations in NFKB1, coding for p105, may cause common variable immunodeficiency due to dysregulation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κΒ) pathway. Monoallelic LOF variants of NFKB1 can predispose to uncontrolled inflammation including sterile necrotizing fasciitis or pyoderma gangrenosum. In this study, we explored the impact of a heterozygous NFKB1 c.C936T/p.R157X LOF variant on immunity in sterile fasciitis patients and their family members. The p50 or p105 protein levels were reduced in all variant carriers. Interleukin-1ß (IL-1ß) and interleukin-8 (IL-8) levels were elevated in vitro, potentially contributing to the very high neutrophil counts observed during fasciitis episodes. Phosphorylation of p65/RelA was reduced in p.R157X neutrophils suggesting defective activation of canonical NF-κB. Oxidative burst after NF-κB-independent phorbol 12-myristate 13-acetate (PMA) stimulation was similar in both p.R157X and control neutrophils. Comparable amounts of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex subunits were found in p.R157X and control neutrophils. However, a compromised oxidative burst was observed in p.R157X neutrophils following activation of NF-κB-dependent mechanisms following stimulation of toll-like receptor 2 (TLR2) and Dectin-1. Neutrophil extracellular trap formation was not affected by p.R157X. In summary, the NFKB1 c.C936T/p.R157X LOF variant has an impact on inflammation and neutrophil function and may play a role in the pathogenesis of sterile necrotizing fasciitis.

IL-17A and TNF synergistically drive expression of proinflammatory mediators in synovial fibroblasts via IκBζ-dependent induction of ELF3.

OBJECTIVE: IL-17A and TNF act in synergy to induce proinflammatory mediators in synovial fibroblasts thus contributing to diseases associated with chronic arthritis. Many of these factors are regulated by transcription factor E74-like factor-3 (ELF3). Therefore, we sought to investigate ELF3 as a downstream target of IL-17A and TNF signalling and to characterize its role in the molecular mechanism of synergy between IL-17A and TNF. METHODS: Regulation of ELF3 expression by IL-17A and TNF was studied in synovial fibroblasts of RA and OA patients and RA synovial explants. Signalling leading to ELF3 mRNA induction and the impact of ELF3 on the response to IL-17A and TNF were studied using siRNA, transient overexpression and signalling inhibitors in synovial fibroblasts and HEK293 cells. RESULTS: ELF3 was marginally affected by IL-17A or TNF alone, but their combination resulted in high and sustained expression. ELF3 expression was regulated by the nuclear factor-κB (NF-κB) pathway and CCAAT/enhancer-binding protein ß (C/EBPß), but its induction required synthesis of the NF-κB co-factor IκB (inhibitor of NF-κB) ζ. siRNA-mediated depletion of ELF3 attenuated the induction of cytokines and matrix metalloproteinases by the combination of IL-17A and TNF. Overexpression of ELF3 or IκBζ showed synergistic effect with TNF in upregulating expression of chemokine (C-C motif) ligand 8 (CCL8), and depletion of ELF3 abrogated CCL8 mRNA induction by the combination of IκBζ overexpression and TNF. CONCLUSION: Altogether, our results establish ELF3 as an important mediator of the synergistic effect of IL-17A and TNF in synovial fibroblasts. The findings provide novel information of the pathogenic mechanisms of IL-17A in chronic arthritis and implicate ELF3 as a potential therapeutic target.

Second and third TNF inhibitors in European patients with axial spondyloarthritis: Effectiveness and impact of the reason for switching.

OBJECTIVE: To investigate real-world effectiveness of tumor necrosis factor inhibitors (TNFi) in patients with axial spondyloarthritis (axSpA) and the association with 1) treatment line (second and third TNFi-series) and 2) reason for withdrawal from the preceding TNFi (lack of efficacy (LOE) versus adverse events (AE)). METHODS: Prospectively collected routine care data from 12 European registries were pooled. Rates for 12-month drug retention and 6-month remission (Ankylosing Spondylitis Disease Activity Score C-reactive protein inactive disease (ASDAS-ID)) were assessed in second and third TNFi-series and stratified by withdrawal reason. RESULTS: We included 8254 s and 2939 third TNFi-series; 12-month drug retention rates were similar (71%). Six-month ASDAS-ID rates were higher for the second (23%) than third TNFi (16%). Twelve-month drug retention rates for patients withdrawing from the preceding TNFi due to AE versus LOE were similar for the second (68% and 67%) and third TNFi (both 68%), while for the second TNFi, rates were lower in primary than secondary non-responders (LOE < 26 versus ≥26 weeks) (58% versus 71%, p< 0.001). Six-month ASDAS-ID rates for the second TNFi were higher if the withdrawal reason was AE (27%) versus LOE (17%), p< 0.001, while similar for the third TNFi (19% versus 13%, p= 0.20). CONCLUSION: A similar proportion of axSpA patients remained on a second and third TNFi after one year, but with low remission rates for the third TNFi. Remission rates on the second TNFi (but not the third) were higher if the withdrawal reason from the preceding TNFi was AE versus LOE.

Activation of NLRP3 Inflammasome in the Skin of Patients with Systemic and Cutaneous Lupus Erythematosus.

NLRP3 inflammasome is suggested to contribute to the complex pathogenesis of systemic lupus erythematosus, but its role in cutaneous lupus erythematosus has not been addressed. This study investigated the expression of NLRP3 inflammasome components and levels of type I interferons in the skin of 20 patients with cutaneous lupus erythematosus. Expression of NLRP1/3, adaptor protein ASC (apoptosis-associated speck-like protein), caspase-1, interferon-α (IFN-α), myxovirus resistance protein (MxA), and interferon-induced proteins 1 and 2 (IFIT 1/2) in the skin was assessed using reverse transcription quantitative real-time PCR (RT-qPCR), western blotting and immunohistochemistry. Serum interferon-α protein levels from 12 patients were measured using digital enzyme-linked immunoassay (ELISA). Interleukin-1ß expression was significantly upregulated in the lesional skin of patients with cutaneous lupus erythematosus compared with their uninvolved skin. However, NLRP1/3, ASC and caspase-1 were not significantly upregulated compared with the skin of control persons. IFN-α and IFN-induced proteins MxA and IFIT1/2 were strongly expressed in cutaneous lupus erythematosus skin. Variability in the expression of NLRP3 inflammasome components among patients suggests heterogeneity of pathological pathways in cutaneous lupus erythematosus.

Severity and progression rate of periodontitis are associated with an increased risk of hypertension of patients attending a university clinic.

BACKGROUND: Although periodontitis is associated with increased risk of hypertension, studies based on new periodontal disease classification is limited. We investigated whether periodontitis severity and progression rate are linked with self-reports on doctor-diagnosed hypertension in a large cohort of patients attending the periodontology clinic at the faculty of dentistry. METHODS: Archived patient files, including radiographic image records and results from full-mouth clinical periodontal examination were screened for inclusion. Data on socioeconomic factors, smoking and oral hygiene habits, and medical history were collected with a questionnaire. RESULTS: Diagnosis and background data were available for 7008 patients. The median (IQR) age was 31.0 (21.0) years; 60.1% (n = 4211) were female. Hypertension was diagnosed in 6.2% (n = 435) of patients. Both periodontitis stage and grade differed (p < 0.001) between patients with or without hypertension. Increased periodontal disease severity was associated with a 20% increasing risk for hypertension; the odds ratio (OR) was 2.63 (95% confidence interval [CI] 1.48-4.68, p < 0.001) in stage IV periodontitis. Increasing periodontitis progression rate was associated with a 35% increased risk for hypertension; the OR was 2.22 (95% CI 1.45-3.40, p < 0.001) in grade C periodontitis. CONCLUSION: Severity and progression rate of periodontitis may be independent risk factors for hypertension in this large cohort of patients attending the university periodontal department.

Lifetime risk of rheumatoid arthritis-associated interstitial lung disease in MUC5B mutation carriers.

OBJECTIVES: To estimate lifetime risk of developing rheumatoid arthritis-associated interstitial lung disease (RA-ILD) with respect to the strongest known risk factor for pulmonary fibrosis, a MUC5B promoter variant. METHODS: FinnGen is a collection of epidemiological cohorts and hospital biobank samples, integrating genetic data with up to 50 years of follow-up within nationwide registries in Finland. Patients with RA and ILD were identified from the Finnish national hospital discharge, medication reimbursement and cause-of-death registries. We estimated lifetime risks of ILD by age 80 with respect to the common variant rs35705950, a MUC5B promoter variant. RESULTS: Out of 293 972 individuals, 1965 (0.7%) developed ILD by age 80. Among all individuals in the dataset, MUC5B increased the risk of ILD with a HR of 2.44 (95% CI: 2.22 to 2.68). Out of 6869 patients diagnosed with RA, 247 (3.6%) developed ILD. In patients with RA, MUC5B was a strong risk factor of ILD with a HR similar to the full dataset (HR: 2.27, 95% CI: 1.75 to 2.95). In patients with RA, lifetime risks of ILD were 16.8% (95% CI: 13.1% to 20.2%) for MUC5B carriers and 6.1% (95% CI: 5.0% to 7.2%) for MUC5B non-carriers. The difference between risks started to emerge at age 65, with a higher risk among men. CONCLUSION: Our findings provide estimates of lifetime risk of RA-ILD based on MUC5B mutation carrier status, demonstrating the potential of genomics for risk stratification of RA-ILD.

A Family With A20 Haploinsufficiency Presenting With Novel Clinical Manifestations and Challenges for Treatment.

BACKGROUND: Tumor necrosis factor α-induced protein 3 gene (TNFAIP3, also called A20) haploinsufficiency (HA20) leads to autoinflammation and autoimmunity. We have recently shown that a p.(Lys91*) mutation in A20 disrupts nuclear factor κB signaling, impairs protein-protein interactions of A20, and leads to inflammasome activation. METHODS: We now describe the clinical presentations and drug responses in a family with HA20 p.(Lys91*) mutation, consistent with our previously reported diverse immunological and functional findings. RESULTS: We report for the first time that inflammasome-mediated autoinflammatory lung reaction caused by HA20 can be treated with interleukin 1 antagonist anakinra. We also describe severe anemia related to HA20 successfully treated with mycophenolate. In addition, HA20 p.(Lys91*) was found to associate with autoimmune thyroid disease, juvenile idiopathic arthritis, psoriasis, liver disease, and immunodeficiency presenting with specific antibody deficiency and genital papillomatosis. CONCLUSIONS: We conclude that HA20 may lead to combination of inflammation, immunodeficiency, and autoimmunity. The condition may present with variable and unpredictable symptoms with atypical treatment responses.

Impact of discordance between patient's and evaluator's global assessment on treatment outcomes in 14 868 patients with spondyloarthritis.

OBJECTIVES: To assess the impact of 'patient's minus evaluator's global assessment of disease activity' (ΔPEG) at treatment initiation on retention and remission rates of TNF inhibitors (TNFi) in psoriatic arthritis (PsA) and axial spondyloarthritis (axSpA) patients across Europe. METHODS: Real-life data from PsA and axSpA patients starting their first TNFi from 11 countries in the European Spondyloarthritis Research Collaboration Network were pooled. Retention rates were compared by Kaplan-Meier analyses with log-rank test and by Cox regression, and remission rates by χ2 test and by logistic regression across quartiles of baseline ΔPEG, separately in female and male PsA and axSpA patients. RESULTS: We included 14 868 spondyloarthritis (5855 PsA, 9013 axSpA) patients. Baseline ΔPEG was negatively associated with 6/12/24-months' TNFi retention rates in female and male PsA and axSpA patients (P <0.001), with 6/12/24-months' BASDAI < 2 (P ≤0.002) and ASDAS < 1.3 (P ≤0.005) in axSpA patients, and with DAS28CRP(4)<2.6 (P ≤0.04) and DAPSA28 ≤ 4 (P ≤0.01), but not DAS28CRP(3)<2.6 (P ≥0.13) in PsA patients, with few exceptions on remission rates. Retention and remission rates were overall lower in female than male patients. CONCLUSION: High baseline patient's compared with evaluator's global assessment was associated with lower 6/12/24-months' remission as well as retention rates of first TNFi in both PsA and axSpA patients. These results highlight the importance of discordance between patient's and evaluator's perspective on disease outcomes.

Retention and response rates in 14 261 PsA patients starting TNF inhibitor treatment-results from 12 countries in EuroSpA.

OBJECTIVE: To investigate TNF inhibitor (TNFi) retention and response rates in European biologic-naïve patients with PsA. METHODS: Prospectively collected data on PsA patients in routine care from 12 European registries were pooled. Heterogeneity in baseline characteristics between registries were explored (analysis of variance and pairwise comparison). Retention rates (Kaplan-Meier), clinical remission [28-joint count DAS (DAS28) <2.6; 28 joint Disease Activity index for Psoriatic Arthritis ⩽4] and ACR criteria for 20% improvement (ACR20)/ACR50/ACR70 were calculated, including LUNDEX adjustment. RESULTS: Overall, 14 261 patients with PsA initiated a first TNFi. Considerable heterogeneity of baseline characteristics between registries was observed. The median 12-month retention rate (95% CI) was 77% (76, 78%), ranging from 68 to 90% across registries. Overall, DAS28/28 joint Disease Activity index for Psoriatic Arthritis remission rates at 6 months were 56%/27% (LUNDEX: 45%/22%). Six-month ACR20/50/70 responses were 53%/38%/22%, respectively. In patients initiating a first TNFi after 2009 with registered fulfilment of ClASsification for Psoriatic ARthritis (CASPAR) criteria (n = 1980) or registered one or more swollen joint at baseline (n = 5803), the retention rates and response rates were similar to those found overall. CONCLUSION: Approximately half of >14 000 patients with PsA who initiated first TNFi treatment in routine care were in DAS28 remission after 6 months, and three-quarters were still on the drug after 1 year. Considerable heterogeneity in baseline characteristics and outcomes across registries was observed. The feasibility of creating a large European database of PsA patients treated in routine care was demonstrated, offering unique opportunities for research with real-world data.

Behçet disease (BD) and BD-like clinical phenotypes: NF-κB pathway in mucosal ulcerating diseases.

Behçet's disease (BD) is a heterogeneous multi-organ disorder in search of a unified pathophysiological theory and classification. The disease frequently has overlapping features resembling other disease clusters, such as vasculitides, spondyloarthritides and thrombophilias with similar genetic risk variants, namely HLA-B*51, ERAP1, IL-10, IL-23R. Many of the BD manifestations, such as unprovoked recurrent episodes of inflammation and increased expression of IL-1, IL-6 and TNFα, overlap with those of the hereditary monogenic autoinflammatory syndromes, positioning BD at the crossroads between autoimmune and autoinflammatory syndromes. BD-like disease associates with various inborn errors of immunity, including familial Mediterranean fever, conditions related to dysregulated NF-κB activation (eg TNFAIP3, NFKB1, OTULIN, RELA, IKBKG) and either constitutional trisomy 8 or acquired trisomy 8 in myelodysplastic syndromes. We review here the recent advances in the immunopathology of BD, BD-like diseases and the NF-κB pathway suggesting new elements in the elusive BD etiopathogenesis.

Gain-of-function CEBPE mutation causes noncanonical autoinflammatory inflammasomopathy.

BACKGROUND: CCAAT enhancer-binding protein epsilon (C/EBPε) is a transcription factor involved in late myeloid lineage differentiation and cellular function. The only previously known disorder linked to C/EBPε is autosomal recessive neutrophil-specific granule deficiency leading to severely impaired neutrophil function and early mortality. OBJECTIVE: The aim of this study was to molecularly characterize the effects of C/EBPε transcription factor Arg219His mutation identified in a Finnish family with previously genetically uncharacterized autoinflammatory and immunodeficiency syndrome. METHODS: Genetic analysis, proteomics, genome-wide transcriptional profiling by means of RNA-sequencing, chromatin immunoprecipitation (ChIP) sequencing, and assessment of the inflammasome function of primary macrophages were performed. RESULTS: Studies revealed a novel mechanism of genome-wide gain-of-function that dysregulated transcription of 464 genes. Mechanisms involved dysregulated noncanonical inflammasome activation caused by decreased association with transcriptional repressors, leading to increased chromatin occupancy and considerable changes in transcriptional activity, including increased expression of NLR family, pyrin domain-containing 3 protein (NLRP3) and constitutively expressed caspase-5 in macrophages. CONCLUSION: We describe a novel autoinflammatory disease with defective neutrophil function caused by a homozygous Arg219His mutation in the transcription factor C/EBPε. Mutated C/EBPε acts as a regulator of both the inflammasome and interferome, and the Arg219His mutation causes the first human monogenic neomorphic and noncanonical inflammasomopathy/immunodeficiency. The mechanism, including widely dysregulated transcription, is likely not unique for C/EBPε. Similar multiomics approaches should also be used in studying other transcription factor-associated diseases.

Functional analysis of synovial fluid from osteoarthritic knee and carpometacarpal joints unravels different molecular profiles.

OBJECTIVE: In this work, we aimed to elucidate the molecular mechanisms driving primary OA. By studying the dynamics of protein expression in two different types of OA joints we searched for similarities and disparities to identify key molecular mechanisms driving OA. METHODS: For this purpose, human SF samples were obtained from CMC-I OA and knee joint of OA patients. SF samples were analysed by label-free quantitative liquid chromatography mass spectrometry. Disease-relevant proteins identified in proteomics studies, such as clusterin, paraoxonase/arylesterase 1 (PON1) and transthyretin were validated by enzyme-linked immunosorbent assays, and on the mRNA level by droplet digital PCR. Functional studies were performed in vitro using primary chondrocytes. RESULTS: Differential proteomic changes were observed in the concentration of 40 proteins including clusterin, PON1 and transthyretin. Immunoassay analyses of clusterin, PON1, transthyretin and other inflammatory cytokines confirmed significant differences in protein concentration in SF of CMC-I and knee OA patients, with primarily lower protein expression levels in CMC-I. Functional studies on chondrocytes unequivocally demonstrated that stimulation with SF obtained from knee OA, in contrast to CMC-I OA joint, caused a significant upregulation in pro-inflammatory response, cell death and hypertrophy. CONCLUSION: This study demonstrates that differential expression of molecular players in SF from different OA joints evokes diverse effects on primary chondrocytes. The pathomolecular mechanisms of OA may significantly differ in various joints, a finding that brings a new dimension into the pathogenesis of primary OA.

Forskolin attenuates the NLRP3 inflammasome activation and IL-1ß secretion in human macrophages.

BACKGROUND: The treatment of nucleotide-binding domain and leucine-rich repeat containing family, pyrin domain containing 3 (NLRP3) inflammasome-mediated pediatric inflammatory diseases is challenging. Here we studied whether cyclic adenosine monophosphate (cAMP) elevator forskolin could attenuate the nigericin-induced NLRP3-inflammasome activation and interleukin-1ß (IL-1ß) secretion in human macrophages. METHODS: The proteins and messenger RNA (mRNA) levels of inflammasome structural proteins and proinflammatory cytokines were measured in forskolin-stimulated nigericin-activated human THP-1 macrophages and primary macrophages. RESULTS: Activation of THP-1 macrophages with nigericin increased the mRNA expression of NLRP3, IL-1ß, and caspase-1 (P < 0.01). Forskolin stimulation had no effect on the mRNA expression of NLRP3, caspase-1, or IL-1ß in nigericin-activated cells (P > 0.05), while their protein levels were significantly decreased (P < 0.05). Forskolin-mediated increase in cytoplasmic cAMP in non-activated cells was attenuated in nigericin-activated macrophages (P < 0.05). Basal IL-1ß secretion increased from 584 to 2696 pg/mL (P < 0.01) in nigericin-activated macrophages; forskolin dose-dependently reduced the nigericin-induced secretion of mature IL-1ß (P < 0.01). Forskolin also inhibited the IL-1ß secretion from activated human primary macrophages. CONCLUSIONS: Forskolin inhibits the NLRP3 inflammasome activation and the secretion of mature IL-1ß, in human macrophages. Forskolin and other cAMP elevator drugs could represent a novel approach for treatment of diseases associated with excessive inflammasome activation, like pediatric inflammatory diseases.

Global Characterization of Protein Secretion from Human Macrophages Following Non-canonical Caspase-4/5 Inflammasome Activation.

Gram-negative bacteria are associated with a wide spectrum of infectious diseases in humans. Inflammasomes are cytosolic protein complexes that are assembled when the cell encounters pathogens or other harmful agents. The non-canonical caspase-4/5 inflammasome is activated by Gram-negative bacteria-derived lipopolysaccharide (LPS) and by endogenous oxidized phospholipids. Protein secretion is a critical component of the innate immune response. Here, we have used label-free quantitative proteomics to characterize global protein secretion in response to non-canonical inflammasome activation upon intracellular LPS recognition in human primary macrophages. Before proteomics, the total secretome was separated into two fractions, enriched extracellular vesicle (EV) fraction and rest-secretome (RS) fraction using size-exclusion centrifugation. We identified 1048 proteins from the EV fraction and 1223 proteins from the RS fraction. From these, 640 were identified from both fractions suggesting that the non-canonical inflammasome activates multiple, partly overlapping protein secretion pathways. We identified several secreted proteins that have a critical role in host response against severe Gram-negative bacterial infection. The soluble secretome (RS fraction) was highly enriched with inflammation-associated proteins upon intracellular LPS recognition. Several ribosomal proteins were highly abundant in the EV fraction upon infection, and our data strongly suggest that secretion of translational machinery and concomitant inhibition of translation are important parts of host response against Gram-negative bacteria sensing caspase-4/5 inflammasome. Intracellular recognition of LPS resulted in the secretion of two metalloproteinases, adisintegrin and metalloproteinase domain-containing protein 10 (ADAM10) and MMP14, in the enriched EV fraction. ADAM10 release was associated with the secretion of TNF, a key inflammatory cytokine, and M-CSF, an important growth factor for myeloid cells probably through ADAM10-dependent membrane shedding of these cytokines. Caspase-4/5 inflammasome activation also resulted in secretion of danger-associated molecules S100A8 and prothymosin-α in the enriched EV fraction. Both S100A8 and prothymosin-α are ligands for toll-like receptor 4 recognizing extracellular LPS, and they may contribute to endotoxic shock during non-canonical inflammasome activation.

Human ß-Defensin 2 Expression in Oral Epithelium: Potential Therapeutic Targets in Oral Lichen Planus.

Human ß-defensin 2 (hBD-2) is a potent antimicrobial peptide that participates in defense against invading bacteria. We recently showed that bacterial components and histamine, through histamine H4 receptor (H4R), are involved in the pathogenesis of the potentially malignant lesion, oral lichen planus (OLP). However, the underlying mechanisms remain unknown. We, therefore, investigated the role of hBD2-histamine crosstalk signaling in promoting OLP pathology. Biopsies from OLP and oral tongue squamous cell carcinoma (OTSCC) patients, and healthy controls were used. Two OTSCC cell lines and normal human oral keratinocytes (HOKs) were used. HBD-2 and other targets were mapped by immunostaining and analyzed by ImageJ2 software. The highly sensitive droplet-digital PCR technology and qRT-PCR were utilized to study the clinically derived and in vitro samples, respectively. H4R was challenged with the specific agonist HST-10 and inverse agonist ST-1007. HBD-2 was highly induced in OLP lesions. In contrast, hBD2 expression was attenuated in OTSCC tissues, while very low levels of hBD-2 messenger RNA (mRNA) were observed in OTSCC cells. Together with tumor necrosis factor-α (TNF-α), histamine upregulated hBD-2 mRNA expression in HOKs. Activation of H4R seems to modulate the expression of epithelial hBD-2. These findings suggest the involvement of hBD-2 in the pathogenesis of OLP and may, thus, be harnessed for therapeutic interventions in OLP.

Serum Epstein-Barr virus DNA, detected by droplet digital PCR, correlates with disease activity in patients with rheumatoid arthritis.

OBJECTIVES: To study the prevalence of asymptomatic activation of Epstein-Barr virus (EBV) in patients with rheumatoid arthritis (RA) and to analyse the correlation of serum EBV DNA with the disease activity. METHODS: The level of EBV DNA was determined by droplet digital PCR assay from the serum of 46 DMARD naive early RA (ERA) and 22 chronic RA (CRA)-patients at study onset. Follow-up samples from 31 ERA and 16 CRA patients were obtained after starting or modifying the anti-rheumatic treatment. EBV DNA was also measured from 33 healthy controls and 9 patients with adult onset Still's disease (AOSD). Disease activity was assessed by the disease activity score (DAS28). RESULTS: At baseline, EBV DNA was detected in the serum of 7 of the 46 ERA patients all of whom had moderate or high disease activity. In the follow-up samples, 11 of 31 patients were EBV DNA positive. At baseline EBV positive patients had significantly higher disease activity (p=0.036) and the concentration of EBV DNA correlated significantly with DAS28 (rs=0.333, p=0.024). EBV DNA was detected in 3 of 22 CRA patients at study onset and in 8 of 16 in the follow-up samples. At follow-up EBV positive patients had significantly higher DAS28 (p=0.027) and the concentration of EBV DNA correlated significantly with DAS28 (rs=0.724, p=0.002). Only one of the healthy controls and none of the AOSD patients were positive for EBV DNA. CONCLUSIONS: Active RA is associated with a lytic EBV infection which may have a role in the pathogenesis of RA.