Inhibitory effect of TNF alpha antibodies on synovial cell interleukin-1 production in rheumatoid arthritis

A longitudinal single-cell atlas of anti-tumour necrosis factor treatment in inflammatory bowel disease

Precision medicine in immune-mediated inflammatory diseases (IMIDs) requires a cellular understanding of treatment response. We describe a therapeutic atlas for Crohn's disease (CD) and ulcerative colitis (UC) following adalimumab, an anti-tumour necrosis factor (anti-TNF) treatment. We generated ~1 million single-cell transcriptomes, organised into 109 cell states, from 216 gut biopsies (41 subjects), revealing disease-specific differences. A systems biology-spatial analysis identified granuloma signatures in CD and interferon (IFN)-response signatures localising to T cell aggregates and epithelial damage in CD and UC. Pretreatment differences in epithelial and myeloid compartments were associated with remission outcomes in both diseases. Longitudinal comparisons demonstrated disease progression in nonremission: myeloid and T cell perturbations in CD and increased multi-cellular IFN signalling in UC. IFN signalling was also observed in rheumatoid arthritis (RA) synovium with a lymphoid pathotype. Our therapeutic atlas represents the largest cellular census of perturbation with the most common biologic treatment, anti-TNF, across multiple inflammatory diseases.

Mir221/222 drive synovial hyperplasia and arthritis by targeting cell cycle inhibitors and chromatin remodeling components

miRNAs constitute fine-tuners of gene expression and are implicated in a variety of diseases spanning from inflammation to cancer. miRNA expression is deregulated in rheumatoid arthritis (RA); however, their specific role in key arthritogenic cells such as the synovial fibroblast (SF) remains elusive. Previous studies have shown that Mir221/222 expression is upregulated in RA SFs. Here, we demonstrate that TNF and IL-1β but not IFN-γ activated Mir221/222 gene expression in murine SFs. SF-specific overexpression of Mir221/222 in huTNFtg mice led to further expansion of SFs and disease exacerbation, while its total ablation led to reduced SF expansion and attenuated disease. Mir221/222 overexpression altered the SF transcriptional profile igniting pathways involved in cell cycle and ECM (extracellular matrix) regulation. Validation of targets of Mir221/222 revealed cell cycle inhibitors Cdkn1b and Cdkn1c, as well as the epigenetic regulator Smarca1. Single-cell ATAC-seq data analysis revealed increased Mir221/222 gene activity in pathogenic SF subclusters and transcriptional regulation by Rela, Relb, Junb, Bach1, and Nfe2l2. Our results establish an SF-specific pathogenic role of Mir221/222 in arthritis and suggest that its therapeutic targeting in specific subpopulations could lead to novel fibroblast-targeted therapies.

The plethora of immunomodulatory drugs: opportunities for immune-mediated kidney diseases

In recent decades, insights into the molecular pathways involved in disease have revolutionized the treatment of autoimmune diseases. A plethora of targeted therapies have been identified and are at varying stages of clinical development in renal autoimmunity. Some of these agents, such as rituximab or avacopan, have been approved for the treatment of immune-mediated kidney disease, but kidney disease lags behind more common autoimmune disorders in new drug development. Evidence is accumulating as to the importance of adaptive immunity, including abnormalities in T-cell activation and signaling, and aberrant B-cell function. Furthermore, innate immunity, particularly the complement and myeloid systems, as well as pathologic responses in tissue repair and fibrosis, play a key role in disease. Collectively, these mechanistic studies in innate and adaptive immunity have provided new insights into mechanisms of glomerular injury in immune-mediated kidney diseases. In addition, inflammatory pathways common to several autoimmune conditions exist, suggesting that the repurposing of some existing drugs for the treatment of immune-mediated kidney diseases is a logical strategy. This new understanding challenges the clinical investigator to translate new knowledge into novel therapies leading to better disease outcomes. This review highlights promising immunomodulatory therapies tested for immune-mediated kidney diseases as a primary indication, details current clinical trials and discusses pathways that could be targeted in the future.

TNFα counteracts interleukin-10 anti-inflammatory pathway through the NOX2-Lyn-SHP-1 axis in human monocytes

TNFα-mediated signaling pathways play a pivotal role in the pathogenesis of inflammatory diseases such as rheumatoid arthritis (RA) and inflammatory bowel disease (IBD) by promoting phagocyte inflammatory functions, notably cytokine release and reactive oxygen species (ROS) production by NOX2. In contrast, interleukin-10 (IL-10), a powerful anti-inflammatory cytokine, potently shuts down phagocyte activation, making IL-10 an attractive therapeutic candidate. However, IL-10 therapy has shown limited efficacy in patients with inflammatory diseases. Here, we report that TNFα blocks IL-10 anti-inflammatory pathways in human monocytes, thereby prolonging inflammation. TNFα decreased IL-10-induced phosphorylation of STAT3 and consequently IL-10-induced expression of the major anti-inflammatory factor, SOCS3. Decreased STAT3 phosphorylation was due to a SHP1/2 phosphatase, as NSC-87877, a SHP1/2 inhibitor, restored STAT3 phosphorylation and prevented the TNFα-induced inhibition of IL-10 signaling. TNFα activated only SHP1 in human monocytes and this activation was NOX2-dependent, as diphenyleneiodonium, a NOX2 inhibitor, suppressed SHP1 activation and STAT3 dephosphorylation triggered by TNFα. ROS-induced activation of SHP1 was mediated by the redox-sensitive kinase, Lyn, as its inhibition impeded TNFα-induced SHP1 activation and STAT3 dephosphorylation. Furthermore, H2O2 recapitulated TNFα-inhibitory activity on IL-10 signaling. Finally, NSC-87877 dampened collagen antibody-induced arthritis (CAIA) in mice. These results reveal that TNFα disrupts IL-10 signaling by inducing STAT3 dephosphorylation through a NOX2-ROS-Lyn-SHP1 axis in human monocytes and that inhibition of SHP1/2 in vivo protects against CAIA. These new findings might explain the poor efficacy of IL-10 therapy in patients with inflammatory diseases and suggest that anti-TNFα agents and SHP1/2 inhibitors could improve the therapeutic use of IL-10.

Matrix metalloproteinases in arthritis: towards precision medicine

Proteolysis of structural molecules of the extracellular matrix (ECM) is an irreversible post-translational modification in all arthropathies. Common joint disorders, including osteoarthritis and rheumatoid arthritis, have been associated with increased levels of matrix remodelling enzymes, including matrix metalloproteinases (MMPs). MMPs, in concert with other host proteinases and glycanases, destroy proteoglycans, collagens and other ECM molecules. MMPs may also control joint remodelling indirectly by signalling through cell-surface receptors or by proteolysis of cytokines and receptor molecules. After synthesis as pro-forms, MMPs can be activated by various types of post-translational modifications, including proteolysis. Once activated, MMPs are controlled by general and specific tissue inhibitors of metalloproteinases (TIMPs). In rheumatoid arthritis, proteolysis of the ECM results in so-called remnant epitopes that enhance and perpetuate autoimmune processes in susceptible hosts. In osteoarthritis, the considerable production of MMP-13 by chondrocytes, often concurrent with mechanical overload, is a key event. Hence, information about the regulation, timing, localization and activities of MMPs in specific disease phases and arthritic entities will help to develop better diagnostics. Insights into beneficial and detrimental effects of MMPs on joint tissue inflammation are also necessary to plan and execute (pre)clinical studies for better therapy and precision medicine with MMP inhibitors. With the advances in proteomics and single-cell transcriptomics, two critical points need attention: neglected neutrophil MMP biology, and the analysis of net proteolytic activities as the result of balances between MMPs and their inhibitors.

Poor Translatability of Biomedical Research Using Animals - A Narrative Review

The failure rate for the translation of drugs from animal testing to human treatments remains at over 92%, where it has been for the past few decades. The majority of these failures are due to unexpected toxicity - that is, safety issues revealed in human trials that were not apparent in animal tests - or lack of efficacy. However, the use of more innovative tools, such as organs-on-chips, in the preclinical pipeline for drug testing, has revealed that these tools are more able to predict unexpected safety events prior to clinical trials and so can be used for this, as well as for efficacy testing. Here, we review several disease areas, and consider how the use of animal models has failed to offer effective new treatments. We also make some suggestions as to how the more human-relevant new approach methodologies might be applied to address this.

Treatments for early-stage Dupuytren's disease: an evidence-based approach

Current treatments for Dupuytren's disease are limited to late-stage disease when patients have developed flexion contractures and have impaired hand function. They all have limitations, including the risk of recurrence and complications. The use of treatments for early-stage disease, such as intralesional steroid injections or radiotherapy which lack a clear biological basis or evidence of effectiveness based robust randomized, double blind, placebo-controlled trials, highlights the desire of patients to access treatments before they develop significant flexion contractures. A detailed understanding of the cellular landscape and molecular signalling in nodules of early-stage disease would permit the identification of potential therapeutic targets. This approach led to the identification of tumour necrosis factor (TNF) as a target. A phase 2a clinical trial identified 40 mg in 0.4 mL adalimumab as the most efficacious dose and a subsequent randomized, double blind, placebo-controlled phase 2b trial showed that four intranodular injections at 3-month intervals resulted in decrease in nodule hardness and size on ultrasound scan at 12 months, and both parameters continued to decrease further at 18 months, 9 months after the final injection. This type of approach provides clinicians with a robust evidence base for advising their patients.

Health functions and related molecular mechanisms of Miconia genus: A systematic review

The Miconia genus is traditionally used in folk medicine in Brazil and other tropical American countries and is represented by 282 species in this region. It is a multifaceted genus of medicinal plants widely used to treat rheumatoid arthritis (RA), pain, inflammatory diseases, and many more therapeutic applications. In the present study, we systematically identify and discuss the literature on in vivo and in vitro studies focusing on the therapeutic potentials and related molecular mechanisms of the Miconia genus. The review also assessed phytochemicals and their pharmacological properties and considered safety concerns related to the genus. Literature searches to identify studies on the Miconia genus were carried out through four main electronic databases, namely PubMed, Embase, Scopus, and Web of Science limited to Medical Subjects Headings (MeSH) and Descriptores en Ciencias de la Salud (DCS) (Health Sciences Descriptors) to identify studies published up to December 2022. The relevant information about the genus was gathered using the keywords 'Miconia', 'biological activities', 'therapeutic mechanisms', 'animal model, 'cell-line model', 'antinociceptive', 'hyperalgesia', 'anti-inflammatory', and 'inflammation'. The therapeutic potentials and mechanisms of action of 14 species from genus Miconia were examined in 18 in vitro studies and included their anti-inflammatory, anticancer, analgesic, antibacterial, cytotoxic, mutagenic, antioxidant, anti-leishmanial, antinociceptive, schistosomicidal, and anti-osteoarthritis potentials, and in eight in vivo studies, assessing their analgesic, antioxidant, antinociceptive, and anti-osteoarthritis activities. Some of the main related molecular mechanisms identified are the modulation of cytokines such as IL-1β, IL-6, and TNF-α, as well as the inhibition of inflammatory mediators and prostaglandin synthesis. The limited number of studies showed that commonly available species from the genus Miconia are safe for consumption. Miconia albicans Sw.Triana and Miconia rubiginosa (Bonpl.) DC was the most frequently used species and showed significant efficacy and potential for developing safe drugs to treat pain and inflammation.

Serum cytokines and bone metabolic markers in patients with rheumatoid arthritis treated with biological disease modifying anti-rheumatic drugs

INTRODUCTION

/objectives Several biological disease-modifying anti-rheumatic drugs (bDMARDs) have been widely used for the management of rheumatoid arthritis (RA). These drugs target different molecules important for the pathophysiology of RA; however, only a few studies have compared the effects of these biological drugs on cytokines and bone metabolic markers. The main aim of this study is to clarify the effects of bDMARDs with different modes of action on the cytokine and bone metabolic marker levels in patients with RA.

METHODS

Patients with RA who were initiated on infliximab, tocilizumab, or abatacept as the first bDMARD were prospectively enrolled in this study. Serum cytokine and bone metabolic marker levels were measured longitudinally, and changes in their levels were compared.

RESULTS

A total of 174 patients were enrolled in this study, with 55, 70, and 49 patients in the infliximab, tocilizumab, and abatacept groups, respectively. At six months, despite the similar clinical effectiveness of the three drugs, changes in the cytokine and bone metabolic marker levels were distinct; interferon-γ and tumor necrosis factor-α levels were significantly increased with infliximab, interleukin-6 levels were increased with tocilizumab, and interleukin-1β and interleukin-8 levels were increased with abatacept treatment. Bone-specific alkaline phosphatase and osteocalcin levels increased more significantly with tocilizumab than with infliximab, while osteopontin and osteonectin levels decreased with infliximab treatment.

CONCLUSIONS

bDMARDs with different modes of action exert different effects on the cytokine and bone metabolic marker levels in patients with RA.

Cytokines in Spondyloarthritis and Inflammatory Bowel Diseases: From Pathogenesis to Therapeutic Implications

Spondyloarthritis and inflammatory bowel diseases are chronic immune disorders of the joints and the gut that often coexist in the same patient, increasing the burden of each disorder, worsening patients' quality of life, and influencing therapeutic strategies. Genetic predisposition, environmental triggers, microbiome features, immune cell trafficking, and soluble factors such as cytokines contribute to the pathogenesis of both articular and intestinal inflammation. Most of the molecular targeted biological therapies developed over the last two decades were based on evidence that specific cytokines may be involved in these immune diseases. Despite pro-inflammatory cytokine pathways sharing the pathogenesis of both articular and gut diseases (i.e., tumor necrosis factor and interleukin-23), several other cytokines (i.e., interleukin-17) may be differently involved in the tissue damage process, depending on the specific disease and the organ involved in inflammation, making difficult the identification of a therapeutic plan that is efficacious for both inflammatory manifestations. In this narrative review, we comprehensively summarize the current knowledge on cytokine involvement in spondyloarthritis and inflammatory bowel diseases, underlining similarities and differences among their pathogenetic pathways; finally, we provide an overview of current and potential future treatment strategies to simultaneously target both articular and gut immune disorders.

Inhibitory Effect of Jinwujiangu Prescription on Peripheral Blood Osteoclasts in Patients with Rheumatoid Arthritis and the Relevant Molecular Mechanism

Rheumatoid arthritis (RA) is a chronic progressive autoimmune disease characterized with high recurrence, high disability, poor prognosis, and long treatment cycles. Versus western medicine, traditional Chinese medicine has the traits of definite efficacy, low toxicity, and side effects in the treatment of RA. Moreover, traditional Chinese medicine also has the advantages of multiple targets, multiple links, and multiple approaches. This study was committed to exploring the effect of Jinwujiangu prescription on peripheral blood osteoclasts in those patients with RA and relevant molecular mechanisms. We first identified 159 common targets by online pharmacology, and there were correlations among these targets; besides, the main signaling pathways involved were inclusive TNF signaling pathway, rheumatoid arthritis, IL-17 signaling pathway, NF-kappa B signaling pathway, Toll-like receptor signaling pathway, etc. Through experimental verification, we found that PBMC cells extracted from human peripheral blood could be successfully induced into osteoclasts, and Jinwujiangu prescription inhibited the generation of osteoclasts from PBMCs of RA patients. CCK-8 and flow cytometry showed that osteoclast viability was significantly decreased and osteoclast apoptosis was significantly increased in the HIF-1α interference group; low-, medium-, and high-dose Jinwujiangu prescription groups; sinapine group; and hydroxychloroquine control group. Moreover, Jinwujiangu prescription and sinapine could inhibit the production of cytokines in peripheral blood osteoclasts and inhibit autophagy in RA patients. The expression level of mTOR was significantly increased in both Jinwu middle- and high-dose groups. In conclusion, this study demonstrated that sinapine, the active target in Jinwujiangu prescription, can act as a HIF-1α inhibitor; activate the mTOR pathway; downregulate the level of autophagy rate, ATG5, beclin-1, and LC3 expression; and inhibit the occurrence of autophagy. The trial registration number of the study is KYW2021010.

Increased Galectin-9 Levels Correlate with Disease Activity in Patients with DMARD-Naïve Rheumatoid Arthritis and Modulate the Secretion of MCP-1 and IL-6 from Synovial Fibroblasts

Background: Fibroblast-like synoviocytes (FLSs) are essential mediators in the expansive growth and invasiveness of rheumatoid synovitis, and patients with a fibroblastic-rich pauci-immune pathotype respond poorly to currently approved antirheumatic drugs. Galectin-9 (Gal-9) has been reported to directly modulate rheumatoid arthritis (RA) FLSs and to hold both pro- and anti-inflammatory properties. The objective of this study was to evaluate clinical and pathogenic aspects of Gal-9 in RA, combining national patient cohorts and cellular models. Methods: Soluble Gal-9 was measured in plasma from patients with newly diagnosed, treatment-naïve RA (n = 98). The disease activity score 28-joint count C-reactive protein (DAS28CRP) and total Sharp score were used to evaluate the disease course serially over a two-year period. Plasma and synovial fluid samples were examined for soluble Gal-9 in patients with established RA (n = 18). A protein array was established to identify Gal-9 binding partners in the extracellular matrix (ECM). Synovial fluid mononuclear cells (SFMCs), harvested from RA patients, were used to obtain synovial-fluid derived FLSs (SF-FLSs) (n = 7). FLSs from patients suffering from knee Osteoarthritis (OA) were collected from patients when undergoing joint replacement surgery (n = 5). Monocultures of SF-FLSs (n = 6) and autologous co-cultures of SF-FLSs and peripheral blood mononuclear cells (PBMCs) were cultured with and without a neutralizing anti-Gal-9 antibody (n = 7). The mono- and co-cultures were subsequently analyzed by flow cytometry, MTT assay, and ELISA. Results: Patients with early and established RA had persistently increased plasma levels of Gal-9 compared with healthy controls (HC). The plasma levels of Gal-9 were associated with disease activity and remained unaffected when adding a TNF-inhibitor to their standard treatment. Gal-9 levels were elevated in the synovial fluid of established RA patients with advanced disease, compared with corresponding plasma samples. Gal-9 adhered to fibronectin, laminin and thrombospondin, while not to interstitial collagens in the ECM protein array. In vitro, a neutralizing Gal-9 antibody decreased MCP-1 and IL-6 production from both RA FLSs and OA FLSs. In co-cultures of autologous RA FLSs and PBMCs, the neutralization of Gal-9 also decreased MCP-1 and IL-6 production, without affecting the proportion of inflammatory FLSs. Conclusions: In RA, pretreatment plasma Gal-9 levels in early RA were increased and correlated with clinical disease activity. Gal-9 levels remained increased despite a significant reduction in the disease activity score in patients with early RA. The in vitro neutralization of Gal-9 decreased both MCP-1 and IL-6 production in an inflammatory subset of RA FLSs. Collectively these findings indicate that the persistent overexpression of Gal-9 in RA may modulate synovial FLS activities and could be involved in the maintenance of subclinical disease activity in RA.

Screening and identification of potential hub genes and immune cell infiltration in the synovial tissue of rheumatoid arthritis by bioinformatic approach

Background

Rheumatoid arthritis (RA) is an autoimmune disease that affects individuals of all ages. The basic pathological manifestations are synovial inflammation, pannus formation, and erosion of articular cartilage, bone destruction will eventually lead to joint deformities and loss of function. However, the specific molecular mechanisms of synovitis tissue in RA are still unclear. Therefore, this study aimed to screen and explore the potential hub genes and immune cell infiltration in RA.

Methods

Three microarray datasets (GSE12021, GSE55457, and GSE55235), from the Gene Expression Omnibus (GEO) database, have been analyzed to explore the potential hub genes and immune cell infiltration in RA. First, the LIMMA package was used to screen the differentially expression genes (DEGs) after removing the batch effect. Then the clusterProfiler package was used to perform functional enrichment analyses. Second, through weighted coexpression network analysis (WGCNA), the key module was identified in the coexpression network of the gene set. Third, the protein-protein interaction (PPI) network was constructed through STRING website and the module analysis was performed using Cytoscape software. Fourth, the CIBERSORT and ssGSEA algorithm were used to analyze the immune status of RA and healthy synovial tissue, and the associations between immune cell infiltration and RA-related diagnostic biomarkers were evaluated. Fifth, we used the quantitative reverse transcription-polymerase chain reaction (qRT-PCR) to validate the expression levels of the hub genes, and ROC curve analysis of hub genes for discriminating between RA and healthy tissue. Finally, the gene-drug interaction network was constructed using DrugCentral database, and identification of drug molecules based on hub genes using the Drug Signature Database (DSigDB) by Enrichr.

Results

A total of 679 DEGs were identified, containing 270 downregulated genes and 409 upregulated genes. DEGs were primarily enriched in immune response and chemokine signaling pathways, according to functional enrichment analysis of DEGs. WGCNA explored the co-expression network of the gene set and identified key modules, the blue module was selected as the key module associated with RA. Seven hub genes are identified when PPI network and WGCNA core modules are intersected. Immune infiltration analysis using CIBERSORT and ssGSEA algorithms revealed that multiple types of immune infiltration were found to be upregulated in RA tissue compared to normal tissue. Furthermore, the levels of 7 hub genes were closely related to the relative proportions of multiple immune cells in RA. The results of the qRT-PCR demonstrated that the relative expression levels of 6 hub genes (CD27, LCK, CD2, GZMB, IL7R, and IL2RG) were up-regulated in RA synovial tissue, compared with normal tissue. Simultaneously, ROC curves indicated that the above 6 hub genes had strong biomarker potential for RA (AUC >0.8).

Conclusions

Through bioinformatics analysis and qRT-PCR experiment, our study ultimately discovered 6 hub genes (CD27, LCK, CD2, GZMB, IL7R, and IL2RG) that closely related to RA. These findings may provide valuable direction for future RA clinical diagnosis, treatment, and associated research.

Calcium-sensing receptor-mediated NLRP3 inflammasome activation in rheumatoid arthritis and autoinflammation

The calcium-sensing receptor (CaSR) is expressed in many cell types - including immune cells and in particular circulating monocytes. Here, the receptor plays an important physiological role as a regulator of constitutive macropinocytosis. This review article provides an overview of the literature on the role of the calcium sensing receptor in the context of inflammatory processes. Special emphasis is laid upon the importance for monocytes in the context of rheumatoid arthritis. We have shown previously, that stimulation of the receptor by increased extracellular Ca²⁺ ([Ca²⁺]_ex) triggers a pro-inflammatory response due to NLRP3 inflammasome assembly and interleukin (IL)-1β release. The underlying mechanism includes macropinocytosis of calciprotein particles (CPPs), which are taken up in a [Ca²⁺]_ex-induced, CaSR dependent manner, and leads to strong IL-1β release. In rheumatoid arthritis (RA), this uptake and the resulting IL-1β release is significantly increased due to increased expression of the receptor. Moreover, increased [Ca²⁺]_ex-induced CPP uptake and IL-1β release is associated with more active disease, while CaSR overexpression has been reported to be associated with cardiovascular complications of RA. Most importantly, however, in animal experiments with arthritic mice, increased local calcium concentrations are present, which in combination with release of fetuin-A from eroded bone could contribute to formation of CPPs. We propose, that increased [Ca²⁺]_ex, CPPs and pro-inflammatory cytokines drive a vicious cycle of inflammation and bone destruction which in turn offers new potential therapeutic approaches.

Increased synovial galectin-3 induce inflammatory fibroblast activation and osteoclastogenesis in patients with rheumatoid arthritis

OBJECTIVE

Galectin-3 (Gal-3) has been suggested as a proinflammatory mediator in rheumatoid arthritis (RA). We aimed to study clinical and pathogenic aspects of Gal-3 in RA.

METHOD

Plasma samples from healthy controls (n = 48) and patients with newly diagnosed, early RA were assayed for soluble Gal-3. In patients with chronic RA (n = 18), Gal-3 was measured in both plasma and synovial fluid. Synovial fluid mononuclear cells were used to purify fibroblast-like synoviocytes (FLSs) and osteoclasts. Monocultures of FLSs and autologous co-cultures of FLSs and peripheral blood mononuclear cells were established and co-incubated with a Gal-3 inhibitor.

RESULTS

Patients with early and chronic RA had persistently increased plasma levels of Gal-3 compared with controls. However, changes in plasma Gal-3 at the level of individuals were associated with long-term disease activity. In seropositive early RA patients, all patients with decreasing plasma Gal-3 from 0 to 3 months had low disease activity after 2 years (p < 0.05). Gal-3 levels in synovial fluid were markedly elevated. In vitro, co-incubation with a Gal-3 inhibitor (GB1107, 10 µM) led to a significant reduction in both interleukin-1β and tumour necrosis factor-α secretion from FLS monocultures (both p < 0.05) and decreased monocyte-derived osteoclastogenesis compared with controls (both p < 0.05).

CONCLUSIONS

Our findings underscore the role of Gal-3 regarding disease activity and tissue destruction in RA. An initial decrease in plasma Gal-3 levels predicted decreased long-term disease activity. Correspondingly, a Gal-3 inhibitor decreased the activity of inflammatory FLSs and osteoclastogenesis in patients with RA.

The Evolution of TNF-α Blockade for the Treatment of Rheumatoid Arthritis

Tumor necrosis factor (TNF)-α is a potent trimeric cytokine which plays a fundamental role in the host immuno-inflammatory response, as well as in homeostasis and development. Although critical for canonical immune function, TNF-α has great destructive potential and is implicated in the development of multiple immune-mediated disorders. Within the context of rheumatoid arthritis (RA), TNF-α acts as a primary pathogenic driver by precipitating a pro-inflammatory cytokine cascade and coordinating the attraction and activation of immune cells, all of which culminate in damage to the synovium. The discovery of the paramount role of TNF-α in the pathophysiology of RA motivated studies to understand the effects of TNF blockade in vitro and in vivo. Promising preclinical results provided the impetus for clinical trials, spearheaded in the 1980s and 90s by Marc Feldmann, which revealed significant improvements across RA symptom scores and finally led to FDA approval in 1998. As of 2021, five TNF-α blocking agents have been widely applied clinically, including infliximab (IFX), etanercept (ETN), adalimumab (ADA), golimumab (GLM) and certolizumab pegol (CZP). All of them successfully ameliorated symptoms of RA and the associated tissue damage, especially in patients not responding to traditional treatment methods. Anti-TNFs are most often administered in combination with methotrexate (MTX) as part of Phase II treatment (i.e., second line). Although the general availability of anti-TNFs has dramatically improved patient outcomes, sustained remission is rare and the mechanism of RA remains incompletely understood. Thus, additional basic and translational research is warranted, towards the aim of developing novel RA treatments.

Post COVID-19 neuropsychiatric complications and therapeutic role for TNF-α inhibitors: a case series study

Background

The post-COVID syndrome is the various physical and neuropsychiatric symptoms after the acute phase of COVID-19. The understanding of pathophysiology of this syndrome and its treatment need to further studies. This study aimed to present three cases of neuropsychiatric symptoms after COVID-19 and effective treatments in these patients.

Case presentation

Three patients with new or progressively neuropsychiatric symptoms such as seizures, attention difficulties, insomnia, confusion and etc., were referred to our clinic about 8 months after severe COVID-19 infection. The patients were assessed with extensive workup includes a neurological exam, brain MRI, LORETA scan, and biochemical and levels of inflammatory serum markers. All patients had elevated levels of TNF-α, poor neurological exam, and abnormal reports of MRI or LORETA scan. Diagnosis of post- COVID neuropsychiatric complications was made for the patients.TNF inhibition with Adalimumab (40 mg/weekly for a month) was initiated for the patients and led to a dramatic improvement of all symptoms.

Conclusions

To our knowledge, this report is the first case series study that suggests TNF inhibitors in the treatment of post-COVID-19 syndrome, especially neuropsychological complications. However, future studies should evaluate the best therapeutic options for this syndrome.

Death by TNF: a road to inflammation

Tumour necrosis factor (TNF) is a central cytokine in inflammatory reactions, and biologics that neutralize TNF are among the most successful drugs for the treatment of chronic inflammatory and autoimmune pathologies. In recent years, it became clear that TNF drives inflammatory responses not only directly by inducing inflammatory gene expression but also indirectly by inducing cell death, instigating inflammatory immune reactions and disease development. Hence, inhibitors of cell death are being considered as a new therapy for TNF-dependent inflammatory diseases.

Effect and Mechanism of siRNAs Targeting IL-1β/TNF-α Combined with BMSCs Transplantation in Ameliorating Rheumatoid Arthritis in Rats

Simple Summary

The study aimed to explore the effect and potential mechanisms of siRNAs targeting IL-1β/TNF-α combined with BMSCs transplantation in ameliorating RA in rats. Collagen-induced arthritis model rats were randomly treated with IL-1β/TNF-α siRNA, BMSCs and IL-1β/TNF-α siRNA + BMSCs for 28 days. Compared with PBS group, BMSCs, siRNA, siRNA + BMSCs treatment groups showed significant lower toe swelling value, the immobility time, the spleen index, serum contents of IL-1β and TNF-α. In addition, the DR-X results showed that the knee carton surface tended to smoothing without bone hyperplasia, suggesting that these three treatments were all able to successfully ameliorate RA symptoms. In addition, compared with PBS group, the protein expression of p-NF-κB-p65 was significantly reduced in the knee of siRNA + BMSCs rats. BMSCs labeled with BrdU were also found in the knee of rats. Moreover, the mRNA expression of IL-1β, TNF-α and NF-κB-P65 in spleen tissue of siRNA + BMSCs rats were all significantly inhibited. Our results demonstrated that IL-1β/TNF-α siRNA, BMSCs and IL-1β/TNF-α siRNA + BMSCs were able to ameliorate RA inflammation by inhibiting the activation of NF-κB signaling pathways and reducing the erosion of articular cartilage, and IL-1β/TNF-α siRNA + BMSCs treatment showed synergism effects. Our study provides a new idea for gene and stem cell therapy for RA.

Abstract

Background: Rheumatoid arthritis (RA) is an autoimmune disease. Bone marrow mesenchymal stem cells (BMSCs) have multilineage differentiation and anti-inflammatory potential, and small interfering RNAs (siRNAs) can inhibit the target gene expression, which make them suitable for ameliorating RA. The current study was aimed to explore the effect and potential mechanisms of siRNAs targeting IL-1β/TNF-α combined with BMSCs transplantation in ameliorating RA in rats. Methods: Collagen-induced arthritis (CIA) model rats were randomly divided into five groups: PBS (Model control group), methotrexate (Positive drug treatment group), BMSCs (BMSCs transplantation group), siRNA (IL-1β/TNF-α siRNAs injection group), siRNA + BMSCs (Both IL-1β/TNF-α siRNAs injection and BMSCs transplantation group). After treatment for 0, 7, 14, 21, 28 days, the ameliorating effect was comprehensively assessed through results of the body weight, toe swelling value, the immobility time of forced swimming, the serum concentrations of IL-1β and TNF-α, knee joint DR-X imaging and pathological analysis as well as of IL-1β, TNF-α and NF-κB mRNA expression in spleen tissue. Furthermore, the potential underlying mechanism involving the NF-κB signaling pathways was also explored. Results: Compared with the PBS group, BMSCs, siRNA, siRNA + BMSCs treatment groups showed significant lower toe swelling value, immobility time, spleen index, serum contents of IL-1β and TNF-α. In addition, the DR-X results showed that the knee carton surface tended to smoothing without bone hyperplasia, suggesting that these three treatments were all able to successfully ameliorate RA symptoms. In addition, compared with the PBS group, the protein expression of p-NF-κB-p65 was significantly reduced in the knees of siRNA + BMSCs rats. BMSCs labeled with BrdU were also found in the knees of rats. Moreover, the mRNA expression of IL-1β, TNF-α and NF-κB-P65 in spleen tissue of siRNA + BMSCs rats were all significantly inhibited. Conclusions: Our results demonstrated for the first time that siRNA + BMSCs was able to ameliorate RA inflammation by inhibiting the activation of NF-κB signaling pathways and reducing the erosion of articular cartilage, and siRNA + BMSCs treatment showed synergism effects in helping ameliorating the inflammation and cartilage repair of RA rats. Therefore, the results of our present study provide a new idea for gene and stem cell therapy for RA.

Angiopoietin-2 Inhibition of Thrombomodulin-Mediated Anticoagulation-A Novel Mechanism That May Contribute to Hypercoagulation in Critically Ill COVID-19 Patients

Hypercoagulation and endothelial dysfunction play central roles in severe forms of COVID-19 infections, but the molecular mechanisms involved are unclear. Increased plasma levels of the inflammatory cytokine and TIE2 receptor antagonist Angiopoietin-2 were reported in severely ill COVID-19 patients. In vitro experiments suggest that Angiopoietin-2 bind and inhibits thrombomodulin. Thrombomodulin is expressed on the luminal surface of endothelial cells where it is an important member of the intrinsic anticoagulant pathway through activation of protein C. Using clinical data, mouse models, and in vitro assays, we tested if Angiopoietin-2 plays a causal role in COVID-19-associated hypercoagulation through direct inhibition of thrombin/thrombomodulin-mediated physiological anticoagulation. Angiopoietin-2 was measured in 61 patients at admission, and after 10 days in the 40 patients remaining in the ICU. We found that Angiopoietin-2 levels were increased in COVID-19 patients in correlation with disease severity, hypercoagulation, and mortality. In support of a direct effect of Angiopoietin-2 on coagulation, we found that injected Angiopoietin-2 in mice associated to thrombomodulin and resulted in a shortened tail bleeding time, decreased circulating levels of activated protein C, and increased plasma thrombin/antithrombin complexes. Conversely, bleeding time was increased in endothelial-specific Angiopoietin-2 knockout mice, while knockout of Tie2 had no effect on tail bleeding. Using in vitro assays, we found that Angiopoietin-2 inhibited thrombomodulin-mediated anticoagulation and protein C activation in human donor plasma. Our data suggest a novel in vivo mechanism for Angiopoietin-2 in COVID-19-associated hypercoagulation, implicating that Angiopoietin-2 inhibitors may be effective in the treatment of hypercoagulation in severe COVID-19 infection.

Polystyrene Nanoplastics Toxicity to Zebrafish: Dysregulation of the Brain-Intestine-Microbiota Axis

In animal species, the brain-gut axis is a complex bidirectional network between the gastrointestinal (GI) tract and the central nervous system (CNS) consisting of numerous microbial, immune, neuronal, and hormonal pathways that profoundly impact organism development and health. Although nanoplastics (NPs) have been shown to cause intestinal and neural toxicity in fish, the role of the neurotransmitter and intestinal microbiota interactions in the underlying mechanism of toxicity, particularly at environmentally relevant contaminant concentrations, remains unknown. Here, the effect of 44 nm polystyrene nanoplastics (PS-NPs) on the brain-intestine-microbe axis and embryo-larval development in zebrafish (Danio rerio) was investigated. Exposure to 1, 10, and 100 μg/L PS-NPs for 30 days inhibited growth and adversely affected inflammatory responses and intestinal permeability. Targeted metabolomics analysis revealed an alteration of 42 metabolites involved in neurotransmission. The content of 3,4-dihydroxyphenylacetic acid (DOPAC; dopamine metabolite formed by monoamine oxidase activity) was significantly decreased in a dose-dependent manner after PS-NP exposure. Changes in the 14 metabolites correlated with changes to 3 microbial groups, including Proteobacteria, Firmicutes, and Bacteroidetes, as compared to the control group. A significant relationship between Firmicutes and homovanillic acid (0.466, Pearson correlation coefficient) was evident. Eight altered metabolites (l-glutamine (Gln), 5-hydroxyindoleacetic acid (5-HIAA), serotonin, 5-hydroxytryptophan (5-HTP), l-cysteine (Cys), l-glutamic acid (Glu), norepinephrine (NE), and l-tryptophan (l-Trp)) had a negative relationship with Proteobacteria although histamine (His) and acetylcholine chloride (ACh chloride) levels were positively correlated with Proteobacteria. An Associated Network analysis showed that Firmicutes and Bacteroidetes were highly correlated (0.969). Furthermore, PS-NPs accumulated in the gastrointestinal tract of offspring and impaired development of F1 (2 h post-fertilization) embryos, including reduced spontaneous movements, hatching rate, and length. This demonstration of transgenerational deficits is of particular concern. These findings suggest that PS-NPs cause intestinal inflammation, growth inhibition, and restricted development of zebrafish, which are strongly linked to the disrupted regulation within the brain-intestine-microbiota axis. Our study provides insights into how xenobiotics can disrupt the regulation of brain-intestine-microbiota and suggests that these end points should be taken into account when assessing environmental health risks of PS-NPs to aquatic organisms.

Incidence Rates of Psoriasis in Children with Inflammatory Bowel Disease and Juvenile Arthritis Treated with TNFi Agents and DMARDs

Objective

To estimate the differential effect of tumor necrosis factor inhibitor (TNFi) therapies and presence/absence of conventional synthetic disease-modifying antirheumatic drug (DMARD) on the incidence of psoriasis in children with inflammatory bowel disease (IBD), juvenile idiopathic arthritis (JIA), and chronic nonbacterial osteomyelitis (CNO).

Methods

This was a retrospective cohort study from 2008 to 2020. TNFi and DMARD exposures were dichotomized as ever/never. The primary outcome was incident psoriasis. Incidence rates (IRs) of psoriasis were stratified by underlying diagnosis, TNFi agent, and DMARD use. Poisson regression was used to assess the IR ratios (IRR) between exposure groups.

Results

5088 children met inclusion criteria – 3794 (75%) had IBD, 1189 (23%) had JIA, and 105 (2%) had CNO. 613 (30%) and 1410 (70%) had TNFi exposure with or without a DMARD, respectively. IRR of developing psoriasis in patients exposed to adalimumab was 2.70 times higher (95% CI: 1.52-4.75; p<0.001) than those who did not receive any TNFi treatment, when controlling for DMARD, sex, and family history of psoriasis. IRR was lower, but not significantly different, for patients exposed to infliximab (IRR=2.34; 95% CI: 1.56-3.51; p<0.001) and etanercept (IRR=2.22; 95% CI: 1.17-4.21; p=0.006) compared to TNFi unexposed patients. IRR of TNFi exposure was lower by 0.25 (p<0.001) in DMARD exposed patients compared to non- DMARD exposed patients.

Conclusion

IRR of TNFi-induced psoriasis was not significantly different amongst adalimumab, infliximab, and etanercept. However, for patients with exposure to any of the TNFi evaluated, the IRR was significantly lower in those also exposed to a DMARD.

Chronic cerebral aspects of long COVID, post-stroke syndromes and similar states share their pathogenesis and perispinal etanercept treatment logic

The chronic neurological aspects of traumatic brain injury, post-stroke syndromes, long COVID-19, persistent Lyme disease, and influenza encephalopathy having close pathophysiological parallels that warrant being investigated in an integrated manner. A mechanism, common to all, for this persistence of the range of symptoms common to these conditions is described. While TNF maintains cerebral homeostasis, its excessive production through either pathogen-associated molecular patterns or damage-associated molecular patterns activity associates with the persistence of the symptoms common across both infectious and non-infectious conditions. The case is made that this shared chronicity arises from a positive feedback loop causing the persistence of the activation of microglia by the TNF that these cells generate. Lowering this excess TNF is the logical way to reducing this persistent, TNF-maintained, microglial activation. While too large to negotiate the blood-brain barrier effectively, the specific anti-TNF biological, etanercept, shows promise when administered by the perispinal route, which allows it to bypass this obstruction.

A Pathogenic Th17/CD38+ Macrophage Feedback Loop Drives Inflammatory Arthritis through TNF-α

The pathobiology of rheumatoid inflammatory diseases, including rheumatoid arthritis (RA) and psoriatic arthritis, involves the interplay between innate and adaptive immune components and resident synoviocytes. Single-cell analyses of patient samples and relevant mouse models have characterized many cellular subsets in RA. However, the impact of interactions between cell types is not fully understood. In this study, we temporally profiled murine arthritic synovial isolates at the single-cell level to identify perturbations similar to those found in human RA. Notably, murine macrophage subtypes like those found in RA patients were expanded in arthritis and linked to promoting the function of Th17 cells in the joint. In vitro experiments identified a capacity for murine macrophages to maintain the functionality and expansion of Th17 cells. Reciprocally, murine Th17 cell-derived TNF-α induced CD38⁺ macrophages that enhanced Th17 functionality. Murine synovial CD38⁺ macrophages were expanded during arthritis, and their depletion or blockade via TNF-α neutralization alleviated disease while reducing IL-17A-producing cells. These findings identify a cellular feedback loop that promotes Th17 cell pathogenicity through TNF-α to drive inflammatory arthritis.

Inside the Joint of Inflammatory Arthritis Patients: Handling and Processing of Synovial Tissue Biopsies for High Throughput Analysis

Inflammatory arthritis is a chronic systemic autoimmune disease of unknown etiology, which affects the joints. If untreated, these diseases can have a detrimental effect on the patient's quality of life, leading to disabilities, and therefore, exhibit a significant socioeconomic impact and burden. While studies of immune cell populations in arthritis patient's peripheral blood have been informative regarding potential immune cell dysfunction and possible patient stratification, there are considerable limitations in identifying the early events that lead to synovial inflammation. The joint, as the site of inflammation and the local microenvironment, exhibit unique characteristics that contribute to disease pathogenesis. Understanding the contribution of immune and stromal cell interactions within the inflamed joint has been met with several technical challenges. Additionally, the limited availability of synovial tissue biopsies is a key incentive for the utilization of high-throughput techniques in order to maximize information gain. This review aims to provide an overview of key methods and novel techniques that are used in the handling, processing and analysis of synovial tissue biopsies and the potential synergy between these techniques. Herein, we describe the utilization of high dimensionality flow cytometric analysis, single cell RNA sequencing, ex vivo functional assays and non-intrusive metabolic characterization of synovial cells on a single cell level based on fluorescent lifetime imaging microscopy. Additionally, we recommend important points of consideration regarding the effect of different storage and handling techniques on downstream analysis of synovial tissue samples. The introduction of new powerful techniques in the study of synovial tissue inflammation, brings new challenges but importantly, significant opportunities. Implementation of novel approaches will accelerate our path toward understanding of the mechanisms involved in the pathogenesis of inflammatory arthritis and lead to the identification of new avenues of therapeutic intervention.

Causal Biological Network Model for Inflammasome Signaling Applied for Interpreting Transcriptomic Changes in Various Inflammatory States

Virtually any stressor that alters the cellular homeostatic state may result in an inflammatory response. As a critical component of innate immunity, inflammasomes play a prominent role in the inflammatory response. The information on inflammasome biology is rapidly growing, thus creating the need for structuring it into a model that can help visualize and enhance the understanding of underlying biological processes. Causal biological network (CBN) models provide predictive power for novel disease mechanisms and treatment outcomes. We assembled the available literature information on inflammasome activation into the CBN model and scored it with publicly available transcriptomic datasets that address viral infection of the lungs, osteo- and rheumatoid arthritis, psoriasis, and aging. The scoring inferred pathway activation leading to NLRP3 inflammasome activation in these diverse conditions, demonstrating that the CBN model provides a platform for interpreting transcriptomic data in the context of inflammasome activation.

Gene-selective transcription promotes the inhibition of tissue reparative macrophages by TNF

Pro-inflammatory TNF is a highly gene-selective inhibitor of the gene expression program of tissue repair and wound healing macrophages.

Anti-TNF therapies are a core anti-inflammatory approach for chronic diseases such as rheumatoid arthritis and Crohn’s Disease. Previously, we and others found that TNF blocks the emergence and function of alternative-activated or M2 macrophages involved in wound healing and tissue-reparative functions. Conceivably, anti-TNF drugs could mediate their protective effects in part by an altered balance of macrophage activity. To understand the mechanistic basis of how TNF regulates tissue-reparative macrophages, we used RNAseq, scRNAseq, ATACseq, time-resolved phospho-proteomics, gene-specific approaches, metabolic analysis, and signaling pathway deconvolution. We found that TNF controls tissue-reparative macrophage gene expression in a highly gene-specific way, dependent on JNK signaling via the type 1 TNF receptor on specific populations of alternative-activated macrophages. We further determined that JNK signaling has a profound and broad effect on activated macrophage gene expression. Our findings suggest that TNF’s anti-M2 effects evolved to specifically modulate components of tissue and reparative M2 macrophages and TNF is therefore a context-specific modulator of M2 macrophages rather than a pan-M2 inhibitor.

Fibrinogen-Like Protein 1 Serves as an Anti-Inflammatory Agent for Collagen-Induced Arthritis Therapy in Mice

Fibrinogen-like protein 1 (FGL1) was recently identified as a major ligand of lymphocyte-activation gene-3 (LAG-3) on activated T cells and serves as an immune suppressive molecule for regulation of immune homeostasis. However, whether FGL1 has therapeutic potential for use in the T cell-induced the autoimmune disease, rheumatoid arthritis (RA), is still unknown. Here, we attempted to evaluate the effect of FGL1 protein on arthritis progression. We also evaluated potential adverse events in a collagen-induced arthritis (CIA) mouse model. We first confirmed that soluble Fgl1 protein could specifically bind to surface Lag-3 receptor on 3T3-Lag-3 cells and further inhibit interleukin (IL-2) and interferon gamma (IFNγ) secretion from activated primary mouse T cells by 95% and 43%, respectively. Intraperitoneal administration of Fgl1 protein significantly decreased the inflammatory cytokine level (i.e., IL-1β and IL-6) in local paw tissue, and prevented joint inflammation, cellular infiltration, bone deformation and attenuated collagen-induced arthritis progression in vivo. We further demonstrated that exogenous Fgl1 does not cause obvious adverse events during treatment by monitoring body weight and liver weight, and assessing the morphology of several organs (i.e., heart, liver, spleen, lung and kidney) by pathological studies. We expect that Fgl1 protein may be suitable to serve as a potential therapeutic agent for treatment of RA or even other types of T cell-induced autoimmune or inflammatory diseases in the future.

The Role of TNF-α in the Pathogenesis of Temporomandibular Disorders

Temporomandibular disorder (TMD) is an oral dentofacial disease that is related to multiple factors such as disordered dental occlusion, emotional stress, and immune responses. In the past decades, tumor necrosis factor-alpha (TNF-α), a pleiotropic cytokine, has provided valuable insight into the pathogenesis of TMD, particularly in settings associated with inflammation. It is thought that TNF-α participates in the pathogenesis of TMD by triggering immune responses, deteriorating bone and cartilage, and mediating pain in the temporomandibular joint (TMJ). Initially, TNF-α plays the role of "master regulator" in the complex immune network by increasing or decreasing the production of other inflammatory cytokines. Then, the effects of TNF-α on cells, particularly on chondrocytes and synovial fibroblasts, result in pathologic cartilage degradation in TMD. Additionally, multiple downstream cytokines induced by TNF-α and neuropeptides can regulate central sensitization and inflammatory pain in TMD. Previous studies have also found some therapies target TMD by reducing the production of TNF-α or blocking TNF-α-induced pathways. All this evidence highlights the numerous associations between TNF-α and TMD; however, they are currently not fully understood and further investigations are still required for specific mechanisms and treatments targeting specific pathways. Therefore, in this review, we explored general mechanisms of TNF-α, with a focus on molecules in TNF-α-mediated pathways and their potential roles in TMD treatment. In view of the high clinical prevalence rate of TMD and damage to patients' QOL, this review provides adequate evidence for studying links between inflammation and TMD in further research and investigation.

How diseases caused by parasites allowed a wider understanding of disease in general: my encounters with parasitology in Australia and elsewhere over the last 50 years

This is an account of how it can prove possible to carve a reasonable scientific career by following what brought most scientific thrill rather than pursue a safe, institution-directed, path. The fascination began when I noticed, quite unexpectedly, that the normal mouse immune response causes Babesia microti to die, en masse, inside circulating red cells. It eventuated that prior Bacillus Calmette Guerin infection caused the same outcome, even before the protozoal infection became patent. It also rendered mice quite immune, long term. I acquired an obsession about this telling us how little we know. Surrounded by basic immunologists, parasitologists and virologists in London, I had been given, in the days that funding was ample, the opportunity to follow any promising lead with a free hand. Through Bacillus Calmette Guerin, this meant stumbling through a set of phenomena that were in their infancies, and could be explained only through nebulous novel soluble mediators such as TNF, described the following year as causing the in vivo necrosis of tumours in mice. Beginning with malarial disease pathogenesis, I followed TNF wherever it led, into innate immunity, acute and chronic infections, neurophysiology and neurodegenerative diseases, in all of which states awareness of the role of this cytokine is still growing fast. Many of these steps can be illustrated and expanded upon in parasitic diseases. Covering the importance of TNF in the pathogenesis of neurodegenerative disease has proved to be highly illuminating, scientifically and otherwise. But the insights it has given me into understanding the temptations to which patent-owners can succumb when faced with opportunities to put money before people is not for the faint hearted. Clearly, parasitologists inhabit a much more common-good yet science-orientated, civilised, world.

Bromelain Extract Exerts Antiarthritic Effects via Chondroprotection and the Suppression of TNF-α-Induced NF-κB and MAPK Signaling

Bromelain, a mixture of proteases in pineapple rhizome, has beneficial biological properties. Following absorption, the compound remains biologically active in mammalian blood and tissues. Bromelain has multiple clinical and therapeutic applications because of its anti-arthritic activities. Anti-inflammation is one of the putative therapeutic effects of bromelain on osteoarthritis (OA) and rheumatoid arthritis (RA), but the molecular mechanisms in cartilage and synovial fibroblast has not been reported. Thus, in this study, interleukin (IL)-1β/oncostatin M-induced porcine cartilage and TNF-α-induced synovial fibroblast were used as the inflamed OA and RA models, respectively. The results demonstrated the chondroprotective effects of bromelain on cartilage degradation and the downregulation of inflammatory cytokine (tumor necrosis factor (TNF)-α, IL-1β, IL-6, IL-8) expression in TNF-α-induced synovial fibroblasts by suppressing NF-κB and MAPK signaling. The evidence from this study supported and explained the anti-inflammatory and analgesic effects of bromelain on arthritis in animal models and clinical studies.

Roles of IL-1 and IL-10 family cytokines in the progression of systemic lupus erythematosus: Friends or foes?

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease of unknown etiology that can affect nearly every organ system in the body. Besides genetic and environmental factors, unbalanced pro-inflammatory and anti-inflammatory cytokines contribute to immune dysregulation, trigger an inflammatory response, and induce tissue and organ damage. Inflammatory responses in SLE can be promoted and/or maintained by the availability of cytokines that are overproduced systemically and/or in local tissues. Several key cytokines have been considered potential targets for the reduction of chronic inflammation in SLE. Recent studies indicated that dysregulated production of several cytokines, including those of the IL-1 family and IL-10 family, orchestrate immune activation and self-tolerance, play critical roles in the pathogenesis of SLE. Among IL-1 family cytokines, IL-1, IL-18, IL-33, IL-36, IL-37, and IL-38 had been the most thoroughly investigated in SLE. Additionally, IL-10 family cytokines, IL-10, IL-20, IL-22, IL-26, IL-28, and IL-29 are dysregulated in SLE. Therefore, a better understanding of the initiation and progression of SLE may provide suitable novel targets for therapeutic intervention. In this review, we discuss the involvement of inflammation in the pathogenesis of SLE, with a focus on IL-1 family and IL-10 family cytokines, and highlight pathophysiological approaches and therapeutic potential for treating SLE.

A Peptide Derived from IKK-Interacting Protein Attenuates NF-κB Activation and Inflammation

The IκB kinase (IKK) complex plays a vital role in regulating the NF-κB activation. Aberrant NF-κB activation is involved in various inflammatory diseases. Thus, targeting IKK activation is an ideal therapeutic strategy to cure and prevent inflammatory diseases related to NF-κB activation. In a previous study, we demonstrated that IKK-interacting protein (IKIP) inhibits the phosphorylation of IKKα/β and the activation of NF-κB through disruption of the formation of IKK complex. In this study, we identified a 15-aa peptide derived from mouse IKIP (46-60 aa of IKIP), which specifically suppressed IKK activation and NF-κB targeted gene expression via disrupting the association of IKKβ and NEMO. Importantly, administration of the peptide reduced LPS-induced acute inflammation and attenuated Zymosan-induced acute arthritis in mice. These findings suggest that this IKIP peptide may be a promising therapeutic reagent in the prevention and treatment of inflammatory diseases.

Background to new treatments for COVID-19, including its chronicity, through altering elements of the cytokine storm

Anti-tumour necrosis factor (TNF) biologicals, Dexamethasone and rIL-7 are of considerable interest in treating COVID-19 patients who are in danger of, or have become, seriously ill. Yet reducing sepsis mortality by lowering circulating levels of TNF lost favour when positive endpoints in earlier simplistic models could not be reproduced in well-conducted human trials. Newer information with anti-TNF biologicals has encouraged reintroducing this concept for treating COVID-19. Viral models have had encouraging outcomes, as have the effects of anti-TNF biologicals on community-acquired COVID-19 during their long-term use to treat chronic inflammatory states. The positive outcome of a large scale trial of dexamethasone, and its higher potency late in the disease, harmonises well with its capacity to enhance levels of IL-7Rα, the receptor for IL-7, a cytokine that enhances lymphocyte development and is increased during the cytokine storm. Lymphoid germinal centres required for antibody-based immunity can be harmed by TNF, and restored by reducing TNF. Thus the IL-7- enhancing activity of dexamethasone may explain its higher potency when lymphocytes are depleted later in the infection, while employing anti-TNF, for several reasons, is much more logical earlier in the infection. This implies dexamethasone could prove to be synergistic with rIL-7, currently being trialed as a COVID-19 therapeutic. The principles behind these COVID-19 therapies are consistent with the observed chronic hypoxia through reduced mitochondrial function, and also the increased severity of this disease in ApoE4-positive individuals. Many of the debilitating persistent aspects of this disease are predictably susceptible to treatment with perispinal etanercept, since they have cerebral origins.

TNFα and Immune Checkpoint Inhibition: Friend or Foe for Lung Cancer?

Tumor necrosis factor-alpha (TNFα) can bind two distinct receptors (TNFR1/2). The transmembrane form (tmTNFα) preferentially binds to TNFR2. Upon tmTNFα cleavage by the TNF-alpha-converting enzyme (TACE), its soluble (sTNFα) form is released with higher affinity for TNFR1. This assortment empowers TNFα with a plethora of opposing roles in the processes of tumor cell survival (and apoptosis) and anti-tumor immune stimulation (and suppression), in addition to angiogenesis and metastases. Its functions and biomarker potential to predict cancer progression and response to immunotherapy are reviewed here, with a focus on lung cancer. By mining existing sequencing data, we further demonstrate that the expression levels of TNF and TACE are significantly decreased in lung adenocarcinoma patients, while the TNFR1/TNFR2 balance are increased. We conclude that the biomarker potential of TNFα alone will most likely not provide conclusive findings, but that TACE could have a key role along with the delicate balance of sTNFα/tmTNFα as well as TNFR1/TNFR2, hence stressing the importance of more research into the potential of rationalized treatments that combine TNFα pathway modulators with immunotherapy for lung cancer patients.

Ulcerative colitis: shedding light on emerging agents and strategies in preclinical and early clinical development

INTRODUCTION

Ulcerative colitis (UC) is an inflammatory disease of the large intestine. Progress in preclinical therapeutic target discovery and clinical trial design has resulted in the approval of new therapies. Nonetheless, remission rates remain below 30% thus underlining the need for novel, more effective therapies.

AREAS COVERED

This paper reviews current experimental techniques available for drug testing in intestinal inflammation and examines new therapies in clinical development for the treatment of UC. The authors searched the literature for 'ulcerative colitis' AND 'preclinical' OR 'drug target/drug name' (i.e. infliximab, vedolizumab, IL-12, IL-23, JAK, etc.). Studies that included preclinical in vivo or in vitro experiments are discussed. The clinicaltrial.gov site was searched for 'ulcerative colitis' AND 'Recruiting' OR 'Active, not recruiting' AND 'Interventional (Clinical Trial)' AND 'early phase 1' OR 'phase 1' OR 'phase 2' OR 'phase 3.'

EXPERT OPINION

Using in vivo, ex vivo, and/or in vitro models could increase the success rates of drugs moving to clinical trials, and hence increase the efficiency of this costly process. Selective JAK1 inhibitors, S1P modulators, and anti-p19 antibodies are the most promising options to improve treatment effectiveness. The development of drugs with gut-restricted exposure may provide increased efficacy and an improved safety.

Reactivation of latent tuberculosis with TNF inhibitors: critical role of the beta 2 chain of the IL-12 receptor

Tumor necrosis factor (TNF) inhibitors have improved a lot the treatment of numerous diseases, with the well-known example of rheumatoid arthritis (RA). In the early 2000s, postmarketing data quickly revealed an alarming number of severe tuberculosis (TB) under such treatment. These findings were consistent with previous results in mice where TNF is essential for lymph node formation and granuloma organization. The effects of TNF inhibition on RA synovium structure are very similar to those on granuloma, with changes in cellular interactions, cytokine, and chemokine production. In addition to the role of TNF in granuloma, the interleukin (IL)-12/interferon (IFN)-γ pathway is required for an efficient host defense against TB. Primary and secondary immunodeficiencies affecting this pathway lead to severe bacillus Calmette-Guérin (BCG) reaction or full TB. Any chronic inflammation as in RA induces a systemic Th1 defect that predisposes to TB through specific downregulation of the IL-12Rß2 chain. When TNF inhibitors are initiated, this transiently increases this risk of TB, through effects on cellular interactions in a latent TB granuloma. At a later stage, when a better control disease activity is obtained, the risk of TB is reduced but not abrogated. Given the clear benefit from TNF inhibition, latent TB infection screening at baseline is essential for an optimal safety.

Interplay of Inflammatory, Antigen and Tissue-Derived Signals in the Development of Resident CD8 Memory T Cells

CD8 positive, tissue resident memory T cells (TRM) are a specialized subset of CD8 memory T cells that surveil tissues and provide critical first-line protection against tumors and pathogen re-infection. Recently, much effort has been dedicated to understanding the function, phenotype and development of TRM. A myriad of signals is involved in the development and maintenance of resident memory T cells in tissue. Much of the initial research focused on the roles tissue-derived signals play in the development of TRM, including TGFß and IL-33 which are critical for the upregulation of CD69 and CD103. However, more recent data suggest further roles for antigenic and pro-inflammatory cytokines. This review will focus on the interplay of pro-inflammatory, tissue and antigenic signals in the establishment of resident memory T cells.

Therapeutic use of specific tumour necrosis factor inhibitors in inflammatory diseases including COVID-19

Coronavirus disease 2019 (COVID-19) has caused significant devastation globally. Despite the development of several vaccines, with uncertainty around global uptake and vaccine efficacy, the need for effective therapeutic agents remains. Increased levels of cytokines including tumour necrosis factor are significant in the pathogenesis of COVID-19 and associated with poor outcomes including ventilator requirement and mortality. Repurposing tumour necrosis factor blocker therapy used in conditions such as rheumatoid arthritis and inflammatory bowel disease seems promising, with early feasibility data showing a reduction in circulation of pro-inflammatory cytokines and encouraging the evaluation of such interventions in preventing disease progression and clinical deterioration in patients with COVID-19. Here, we examine the biological activities of tumour necrosis factor inhibitors indicative of their potential in COVID-19 and briefly outline the randomised control trials assessing their benefit-risk profile in COVID-19 therapy.

Crosstalk between Interleukin-1β and Type I Interferons Signaling in Autoinflammatory Diseases

Interleukin-1β (IL-1β) and type I interferons (IFNs) are major cytokines involved in autoinflammatory/autoimmune diseases. Separately, the overproduction of each of these cytokines is well described and constitutes the hallmark of inflammasomopathies and interferonopathies, respectively. While their interaction and the crosstalk between their downstream signaling pathways has been mostly investigated in the frame of infectious diseases, little information on their interconnection is still available in the context of autoinflammation promoted by sterile triggers. In this review, we will examine the respective roles of IL-1β and type I IFNs in autoinflammatory/rheumatic diseases and analyze their potential connections in the pathophysiology of some of these diseases, which could reveal novel therapeutic opportunities.

Tear Film Cytokine Profile of Patients With the Boston Keratoprosthesis Type 1: Comparing Patients With and Without Glaucoma

Purpose

Inflammatory cytokines are involved in glaucoma pathogenesis. The purpose is to compare cytokine levels in the tear film of Boston keratoprosthesis (KPro) patients with and without glaucoma, relative to controls, and correlate levels with clinical parameters.

Methods

This cross-sectional study enrolled 58 eyes (58 patients): 41 KPro eyes with glaucoma, 7 KPro eyes without glaucoma, and 10 healthy controls. Twenty-seven cytokines were measured by multiplex bead immunoassay. Intraocular pressure (IOP), cup-to-disk ratio (CDR), retinal nerve fiber layer, visual acuity, topical medications, and angle closure were assessed in all KPro eyes. Cytokine levels between groups were analyzed by nonparametric tests, and correlations with clinical parameters by Spearman's test.

Results

Levels of TNF-ɑ, IL-1β, FGF-basic, and IFN-ɣ were significantly higher in KPro with glaucoma compared to KPro without (P = 0.020; 0.008; 0.043; 0.018, respectively). KPro groups had similar characteristics and topical antibiotic/steroid regimen. Levels of IL-1Ra, IL-15, VEGF, and RANTES were significantly higher in KPro with glaucoma compared to controls (P < 0.001; = 0.034; < 0.001; = 0.001, respectively). IL-1β and IFN-ɣ levels were positively correlated with CDR (r = 0.309, P = 0.039 and r = 0.452, P = 0.006, respectively) and IOP (r = 0.292, P = 0.047 and r = 0.368, P = 0.023, respectively). TNF-α and FGF-basic levels were positively correlated with CDR (r = 0.348, P = 0.022 and r = 0.344, P = 0.021, respectively).

Conclusions

TNF-α, IL-1β, FGF-basic, IFN-ɣ are elevated in tears of KPro patients with glaucoma and correlate with CDR and IOP. These results show, for the first time in humans, concordance with documented elevations of TNF-α and IL-1β in the murine KPro model. Ocular surface inflammation may reflect inflammatory processes of KPro glaucoma.

TNF in the era of immune checkpoint inhibitors: friend or foe?

Immune checkpoint inhibitors (ICIs) are effective in the treatment of patients with advanced cancer and have emerged as a pillar of standard cancer care. However, their use is complicated by adverse effects known as immune-related adverse events (irAEs), including ICI-induced inflammatory arthritis. ICI-induced inflammatory arthritis is distinguished from other irAEs by its persistence and requirement for long-term treatment. TNF inhibitors are commonly used to treat inflammatory diseases such as rheumatoid arthritis, spondyloarthropathies and inflammatory bowel disease, and have also been adopted as second-line agents to treat irAEs refractory to glucocorticoid treatment. Experiencing an irAE is associated with a better antitumour response after ICI treatment. However, whether TNF inhibition can be safely used to treat irAEs without promoting cancer progression, either by compromising ICI therapy efficacy or via another route, remains an open question. In this Review, we discuss clinical and preclinical studies that address the relationship between TNF, TNF inhibition and cancer. The bulk of the evidence suggests that at least short courses of TNF inhibitors are safe for the treatment of irAEs in patients with cancer undergoing ICI therapy. Data from preclinical studies hint that TNF inhibition might augment the antitumour effect of ICI therapy while simultaneously ameliorating irAEs.

The medicinal plant Tabebuia impetiginosa potently reduces pro-inflammatory cytokine responses in primary human lymphocytes

Bark from the Handroanthus impetiginosus (Mart. ex DC.) Mattos (Bignoniaceae) tree has long been used in traditional South American healing practises to treat inflammation. However, its anti-inflammatory activity has not been closely examined. Here we use chemical extraction, qualitative phytochemical examination, toxicity testing and quantitative examination of anti-inflammatory activity on human cells ex vivo. All extracts were found to be nontoxic. We found different extracts exhibited unique cytokine profiles with some extracts outperforming a positive control used in the clinic. These results verify the immunomodulatory activity of Handroanthus impetiginosus (Mart. ex DC.) Mattos (Bignoniaceae) tree bark-derived compounds. Collectively, combining a lack of toxicity and potency in human immune cells supports further fractionation and research.

Expression of sterile-α and armadillo motif in rheumatoid arthritis monocytes correlates with TLR2 induced IL-1β and disease activity

OBJECTIVE

Cartilage and bone damage in rheumatoid arthritis (RA) are associated with elevated IL-1β. The effects of IL-1β can be reduced by biological therapies that target IL-1β or TNFα. However, the mechanisms responsible for increased IL-1β and the effect of anti-TNFα have not been fully elucidated. Recently, sterile-α and armadillo motif-containing protein (SARM) was identified as a negative regulator of toll-like receptor (TLR) induced IL-1β secretion through an interaction with the inflammasome. This study set out to investigate SARM during TLR induced IL-1β secretion in RA peripheral blood monocytes and in patients commencing anti-TNFα treatment.

METHODS

Monocytes were isolated from RA patients and healthy controls; disease activity was measured by DAS28. IL-1β secretion was measured by ELISA following TLR1/2, TLR4 and TLR7/8 stimulation. The mRNA expression of SARM, IL-1β and the components of the NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome were measured by quantitative PCR. SARM protein expression was measured by western blotting.

RESULTS

TLR1/2 activation induced elevated IL-1β in RA monocytes compared with heathy controls (p= 0.0009), which negatively correlated with SARM expression (p = 0.0086). Lower SARM expression also correlated with higher disease activity (p = 0.0246). Additionally, patients responding to anti-TNFα treatment demonstrated a rapid upregulation of SARM, which was not observed in non-responders.

CONCLUSION

Together, these data highlight a potential contribution from SARM to RA pathophysiology where decreased SARM may lead to elevated IL-1β associated with RA pathogenesis. Furthermore, the data additionally present a potential mechanism by which TNFα blockade can modify IL-1β secretion.

Strategies to Target ADAM17 in Disease: From its Discovery to the iRhom Revolution

For decades, disintegrin and metalloproteinase 17 (ADAM17) has been the object of deep investigation. Since its discovery as the tumor necrosis factor convertase, it has been considered a major drug target, especially in the context of inflammatory diseases and cancer. Nevertheless, the development of drugs targeting ADAM17 has been harder than expected. This has generally been due to its multifunctionality, with over 80 different transmembrane proteins other than tumor necrosis factor α (TNF) being released by ADAM17, and its structural similarity to other metalloproteinases. This review provides an overview of the different roles of ADAM17 in disease and the effects of its ablation in a number of in vivo models of pathological conditions. Furthermore, here, we comprehensively encompass the approaches that have been developed to accomplish ADAM17 selective inhibition, from the newest non-zinc-binding ADAM17 synthetic inhibitors to the exploitation of iRhom2 to specifically target ADAM17 in immune cells.

Appraisal of the Antiarthritic Potential of Prazosin via Inhibition of Proinflammatory Cytokine TNF-α: A Key Player in Rheumatoid Arthritis

Prazosin, a selective α₁ adrenergic receptor antagonist, with documented anti-inflammatory potential, was evaluated for its antiarthritic efficacy by targeting specifically TNF-α. The antiarthritic attribute of prazosin validated through in vitro screening comprised thermally provoked denaturation of bovine serum albumin (BSA) and egg albumin along with membrane stabilization evaluation at a concentration of 100-6400 μg/mL, while in vivo screening comprised formaldehyde-instigated arthritis at the doses of 5, 10, and 20 mg/kg and complete Freund's adjuvant (CFA)-induced arthritis at 20 mg/kg dose. Paw swelling, body weight, arthritic score, hematological parameters, and histological and radiographic examination of ankle joints were assessed for a period of 28 days after CFA immunization. Moreover, the proinflammatory cytokine TNF-α level was also assessed through quantitative real-time polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). Prazosin revealed significant antiarthritic effect evident through protein denaturation inhibition in the egg albumin and the BSA model, stabilization of red blood cell membrane in the membrane stabilizing assay, and reduction in paw volume in formaldehyde-induced arthritis. Likewise, prazosin exhibited propitious antiarthritic effects in the CFA-provoked arthritis model manifested by paw volume and arthritic score alleviation, substantial weight loss prevention, and preservation of the normal hematological and biochemical profile. Histological and X-ray investigation unveiled no substantive structural alterations in treated rat's ankle joints. The TNF-α expression level was also reduced. Thus, the current study is suggestive that prazosin exhibits a strong antiarthritic potential possibly through inhibition of TNF-α.

TLR expression profiles are a function of disease status in rheumatoid arthritis and experimental arthritis

The role of the innate immune system has been established in the initiation and perpetuation of inflammatory disease, but less attention has been paid to its role in the resolution of inflammation and return to homeostasis. Toll-like receptor (TLR) expression profiles were analysed in tissues with differing disease status in rheumatoid arthritis (RA), ankylosing spondylitis (AS), and in experimental arthritis. TLR gene expression was measured in whole blood and monocytes, before and after TNF blockade. In RA and osteoarthritis synovia, the expression of TLRs was quantified by standard curve qPCR. In addition, four distinct stages of disease were defined and validated in collagen-induced arthritis (CIA), the gold standard animal model for RA - pre-onset, early disease, late disease and immunised mice that were resistant to the development of disease. TLR expression was measured in spleens, lymph nodes, blood cells, liver and the paws (inflamed and unaffected). In RA whole blood, the expression of TLR1, 4 and 6 was significantly reduced by TNF blockade but the differences in TLR expression profiles between responders and non-responders were less pronounced than the differences between RA and AS patients. In RA non-responders, monocytes had greater TLR2 expression prior to therapy compared to responders. The expression of TLR1, 2, 4 and 8 was higher in RA synovium compared to control OA synovium. Circulating cytokine levels in CIA resistant mice were similar to naïve mice, but anti-collagen antibodies were similar to arthritic mice. Distinct profiles of inflammatory gene expression were mapped in paws and organs with differing disease status. TLR expression in arthritic paws tended to be similar in early and late disease, with TLR1 and 2 moderately higher in late disease. TLR expression in unaffected paws varied according to gene and disease status but was generally lower in resistant paws. Disease status-specific profiles of TLR expression were observed in spleens, lymph nodes, blood cells and the liver. Notably, TLR2 expression rose then fell in the transition from naïve to pre-onset to early arthritis. TLR gene expression profiles are strongly associated with disease status. In particular, increased expression in the blood precedes clinical manifestation.

Down-Regulation of Colonic ACE2 Expression in Patients With Inflammatory Bowel Disease Responding to Anti-TNF Therapy: Implications for COVID-19

Background and Aims: Angiotensin-converting enzyme II (ACE2) is the key molecule for understanding the pathophysiology of COVID-19. The risk of COVID-19 and impact of immunosuppressive treatment on disease course in patients with inflammatory bowel disease (IBD) remain controversial. We aimed to determine the change of intestinal ACE2 expression before and after biologics treatment including anti-tumor necrosis factor α (anti-TNFα), anti-integrin, and anti-interleukin (IL)12/23 in IBD patients. Methods: We analyzed the ACE2 expression through the public database of paired intestinal biopsies from IBD patients before and after biologic therapy. Change of ACE2 RNA and protein expression were validated in two independent cohorts (Birmingham cohort and Guangzhou cohort). The correlation between ACE2 expression and disease activity was also analyzed. Results: Mining information from the GEO database showed that compared with healthy control, intestinal ACE2 expression was downregulated in ileum of CD patients, while upregulated in colon of both CD and UC patients. Colonic ACE2 RNA expression was decreased significantly in patients responding to anti-TNFα but not anti-integrin and anti-IL12/23, which was validated in the Birmingham cohort. Using the Guangzhou cohort including 53 patients matched by pre- and post-anti-TNFα therapy, colonic ACE2 protein expression was significantly downregulated after anti-TNFα treatment in responders (P < 0.001) rather than non-responders. Colonic ACE2 expression was significantly higher in patients with severe histologically active disease compared with those with moderate (P < 0.0001) and mild (P = 0.0002) histologically active disease. Conclusion: Intestinal inflammation influences the expression of intestinal ACE2 in IBD patients, with different alterations in the ileum and colon. Colonic ACE2 expression was downregulated after anti-TNFα therapy in IBD patients responding to treatment. This might provide new clues regarding the risk of SARS-CoV-2 infection and the potential benefit of sustaining anti-TNFα treatment in patients with IBD.