Selected cytokine pathways in rheumatoid arthritis

Uncovering Mechanisms of Zanthoxylum piperitum Fruits for the Alleviation of Rheumatoid Arthritis Based on Network Pharmacology

Zanthoxylum piperitum fruits (ZPFs) have been demonstrated favorable clinical efficacy on rheumatoid arthritis (RA), but its compounds and mechanisms against RA have not been elucidated. This study was to investigate the compounds and mechanisms of ZPFs to alleviate RA via network pharmacology. The compounds from ZPFs were detected by gas chromatography-mass spectrometry (GC-MS) and screened to select drug-likeness compounds through SwissADME. Targets associated with bioactive compounds or RA were identified utilizing bioinformatics databases. The signaling pathways related to RA were constructed; interactions among targets; and signaling pathways-targets-compounds (STC) were analyzed by RPackage. Finally, a molecular docking test (MDT) was performed to validate affinity between targets and compounds on key signaling pathway(s). GC-MS detected a total of 85 compounds from ZPFs, and drug-likeness properties accepted all compounds. A total of 216 targets associated with compounds 3377 RA targets and 101 targets between them were finally identified. Then, a bubble chart exhibited that inactivation of MAPK (mitogen-activated protein kinase) and activation of PPAR (peroxisome proliferator-activated receptor) signaling pathway might be key pathways against RA. Overall, this work suggests that seven compounds from ZPFs and eight targets might be multiple targets on RA and provide integrated pharmacological evidence to support the clinical efficacy of ZPFs on RA.

Potential Mechanisms of Action of Chinese Patent Medicines for COVID-19: A Review

Coronavirus disease 2019 (COVID-19) is an emergent infectious pneumonia caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is highly contagious and pathogenic. COVID-19 has rapidly swept across the world since it was first discovered in December 2019 and has drawn significant attention worldwide. During the early stages of the outbreak in China, traditional Chinese medicines (TCMs) were involved in the whole treatment process. As an indispensable part of TCM, Chinese patent medicines (CPMs) played an irreplaceable role in the prevention and treatment of this epidemic. Their use has achieved remarkable therapeutic efficacy during the period of medical observation and clinical treatment of mild, moderate, severe, and critical cases and during convalescence. In order to better propagate and make full use of the benefits of TCM in the treatment of COVID-19, this review will summarize the potential target of SARS-CoV-2 as well as the theoretical basis and clinical efficacy of recommended 22 CPMs by the National Health Commission and the Administration of TCM and local provinces or cities in the treatment of COVID-19. Additionally, the study will further analyze the drug composition, potential active ingredients, potential targets, regulated signaling pathways, and possible mechanisms for COVID-19 through anti-inflammatory and immunoregulation, antiviral, improve lung injury, antipyretic and organ protection to provide meaningful information about the clinical application of CPMs.

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.

Gut microbiota mediated the protective effects of tuna oil on collagen-induced arthritis in mice

Rheumatoid arthritis is emerging as a chronic autoimmune disease worldwide. In this study, the beneficial effects of tuna oil (TO) on collagen-induced arthritis (CIA) mice were investigated. Dietary administration of TO relieved arthritis severity and joint bone erosion, and ameliorated systemic inflammation. Furthermore, TO treatments regulated the phosphorylation of nuclear factor-kappa B (NF-κB) and Wnt1/β-catenin signaling pathways in the joint, enhanced osteoblastogenesis biomarkers and suppressed osteoclastogenesis biomarkers, and subsequently re-balanced bone remodeling. Moreover, the impaired intestinal epithelial barrier was repaired after TO treatments, along with gut microbiota modulation. By employing fecal microbiota transplantation, we clarified that the beneficial effects of TO in CIA alleviation were mediated by the modulated gut microbiota. These results indicated that gut microbiota mediated the protective effects of tuna oil on collagen-induced arthritis in mice.

CircMAPK9 promotes the progression of fibroblast-like synoviocytes in rheumatoid arthritis via the miR-140-3p/PPM1A axis

Background

Rheumatoid arthritis (RA) is a chronic inflammatory joint disease, and fibroblast-like synoviocytes (FLSs) are key effector cells in RA development. Mounting evidence indicates that circular RNAs (circRNAs) participate in the occurrence and development of RA. However, the precise mechanism of circRNA mitogen-activated protein kinase (circMAPK9) in the cell processes of FLSs has not been reported.

Methods

The expression levels of circMAPK9, microRNA-140-3p (miR-140-3p), and protein phosphatase magnesium-dependent 1A (PPM1A) were determined by quantitative real-time polymerase chain reaction (qRT-PCR) or western blot assay. Cell proliferation was examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell apoptosis and cycle distribution were assessed by flow cytometry. Cell migration and invasion were tested by transwell assay. All the proteins were inspected by western blot assay. Inflammatory response was evaluated by enzyme-linked immunosorbent assay (ELISA). The interaction between miR-140-3p and circMAPK9 or PPM1A was verified by dual-luciferase reporter assay.

Results

CircMAPK9 and PPM1A were upregulated and miR-140-3p was downregulated in RA patients and FLSs from RA patients (RA-FLSs). CircMAPK9 silence suppressed cell proliferation, migration, invasion, inflammatory response, and promoted apoptosis in RA-FLSs. MiR-140-3p was a target of circMAPK9, and miR-140-3p downregulation attenuated the effects of circMAPK9 knockdown on cell progression and inflammatory response in RA-FLSs. PPM1A was targeted by miR-140-3p, and circMAPK9 could regulate PPM1A expression by sponging miR-140-3p. Furthermore, miR-140-3p could impede cell biological behaviors in RA-FLSs via targeting PPM1A.

Conclusion

CircMAPK9 knockdown might inhibit cell proliferation, migration, invasion, inflammatory response, and facilitate apoptosis in RA-FLSs via regulating miR-140-3p/PPM1A axis, offering a new mechanism for the comprehension of RA development and a new insight into the potential application of circMAPK9 in RA treatment.

Rheumatoid arthritis and osteoporosis: Shared genetic effect, pleiotropy and causality

Rheumatoid arthritis (RA) is associated with increased localized and generalized bone loss, but the complex genetic mechanism between them is still unknown. By leveraging large-scale genome-wide association studies (GWASs) summary statistics and individual-level datasets (i.e. UK Biobank), a series of genetic approaches were conducted. Linkage disequilibrium score regression (LDSC) reveals a shared genetic correlation between RA and estimated bone mineral density (eBMD) (rg = -0.059, p = 0.005). The PLACO analysis has identified 74 lead (8 novel) pleiotropic loci that could be mapped to 99 genes, the genetic functions of which reveal the possible mechanism underlying RA and osteoporosis. In European, genetic risk score (GRS) and comprehensive mendelian randomization (MR) were utilized to evaluate the causal association between RA and osteoporosis in European and Asiany. The increase in GRS of RA could lead to a decrease of eBMD (beta = -0.008, p = 3.77E-6) and a higher risk of facture [odds ratio (OR) = 1.012, p = 0.044]. MR analysis identified that genetically determined RA was causally associated with eBMD (beta = -0.021, p = 4.14E-05) and fracture risk (OR = 1.036, and p = 0.004). Similar results were also observed in Asian that osteoporosis risk could be causally increased by RA (OR = 1.130, p = 1.04E-03) as well as antibodies against citrullinated proteins (ACPA)-positive RA (OR = 1.083, p = 0.015). Overall, our study reveals complex genetic mechanism between RA and osteoporosis and provides strong evidence for crucial role of RA in pathogenesis of osteoporosis.

IL-33 Gene Polymorphisms as Potential Biomarkers of Disease Susceptibility and Response to TNF Inhibitors in Rheumatoid Arthritis, Ankylosing Spondylitis, and Psoriatic Arthritis Patients

Objective

Rheumatoid arthritis (RA), ankylosing spondylitis (AS), and psoriatic arthritis (PsA) belong to inflammatory rheumatic diseases, the group of conditions of unknown etiology. However, a strong genetic component in their pathogenesis has been well established. A dysregulation of cytokine networks plays an important role in the development of inflammatory arthritis. Interleukin 33 (IL-33) is a recently identified member of the IL-1 family. To date, the significance of IL-33 in inflammatory arthritis has been poorly studied. This research aimed to investigate the potential of IL-33 gene polymorphisms to serve as biomarkers for disease susceptibility and TNF inhibitor response in RA, AS, and PsA patients.

Materials and Methods

In total, 735 patients diagnosed with RA, AS, and PsA and 229 healthy individuals were enrolled in the study. Genotyping for three single nucleotide polymorphisms (SNPs) within the IL-33 gene, namely, rs16924159 (A/G), rs10975519 (T/C), and rs7044343 (C/T), was performed using polymerase chain reaction amplification employing LightSNiP assays.

Results

In the present study, the IL-33 rs10975519 CC genotype was associated with a decreased risk of developing RA in females, while the IL-33 rs16924159 polymorphism was associated with the efficacy of anti-TNF therapy and clinical parameters for RA and AS patients. The IL-33 rs16924159 AA genotype correlated with higher disease activity and worse clinical outcomes in RA patients treated with TNF inhibitors, and AS patients carrying the IL-33 rs16924159 AA genotype had higher disease activity and a worse response to anti-TNF therapy. That indicates a deleterious role of the IL-33 rs16924159 AA genotype in the context of RA, as well as AS.

Conclusions

The obtained results suggest that IL-33 gene polymorphisms might be potential candidate biomarkers of disease susceptibility and anti-TNF treatment response in patients with inflammatory rheumatic diseases.

Prediction and Verification of the Major Ingredients and Molecular Targets of Tripterygii Radix Against Rheumatoid Arthritis

Tripterygii Radix exhibits good clinical efficacy and safety in rheumatoid arthritis (RA) patients, but its effective components and mechanism of action are still unclear. The purpose of this study was to explore and verify the major ingredients and molecular targets of Tripterygii Radix in RA using drug-compounds-biotargets-diseases network and protein-protein interaction (PPI) network analyses. The processes and pathways were derived from Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. The most important compounds and biotargets were determined based on the degree values. RA fibroblast-like synoviocytes (RA-FLS) were separated from RA patients and identified by hematoxylin and eosin (HE) staining and immunohistochemistry. The purity of RA-FLS was acquired by flow cytometry marked with CD90 or VCAM-1. RA-FLS were subjected to control, dimethyl sulfoxide (control), kaempferol, or lenalidomide treatment. Cell migration was evaluated by the transwell assay. The relative expression of biotarget proteins and cytokines was analyzed by western blotting and flow cytometry. In total, 144 chemical components were identified from Tripterygii Radix; kaempferol was the most active ingredient among 33 other components. Fourteen proteins were found to be affected in RA from 285 common biotargets. The tumor necrosis factor (TNF) signaling pathway was predicted to be one of the most latent treatment pathways. Migration of RA-FLS was inhibited and the expression of protein kinase B (AKT1), JUN, caspase 3 (CASP3), TNF receptor 1 and 2 (TNFR1 and TNFR2), interleukin-6 (IL-6), and TNF-α was significantly affected by kaempferol. Thus, this study confirmed kaempferol as the effective component of Tripterygii Radix against RA-FLS and TNF signaling pathway and its involvement in the regulation of AKT1, JUN, CASP3, TNFR1, TNFR2, IL-6, and TNF-α expression.

The Therapeutic Landscape of Rheumatoid Arthritis: Current State and Future Directions

Rheumatoid arthritis (RA) is a debilitating autoimmune disease with grave physical, emotional and socioeconomic consequences. Despite advances in targeted biologic and pharmacologic interventions that have recently come to market, many patients with RA continue to have inadequate response to therapies, or intolerable side effects, with resultant progression of their disease. In this review, we detail multiple biomolecular pathways involved in RA disease pathogenesis to elucidate and highlight pathways that have been therapeutic targets in managing this systemic autoimmune disease. Here we present an up-to-date accounting of both emerging and approved pharmacological treatments for RA, detailing their discovery, mechanisms of action, efficacy, and limitations. Finally, we turn to the emerging fields of bioengineering and cell therapy to illuminate possible future targeted therapeutic options that combine material and biological sciences for localized therapeutic action with the potential to greatly reduce side effects seen in systemically applied treatment modalities.

Cannabinoid-based therapy as a future for joint degeneration. Focus on the role of CB2 receptor in the arthritis progression and pain: an updated review

Over the last several decades, the percentage of patients suffering from different forms of arthritis has increased due to the ageing population and the increasing risk of civilization diseases, e.g. obesity, which contributes to arthritis development. Osteoarthritis and rheumatoid arthritis are estimated to affect 50-60% of people over 65 years old and cause serious health and economic problems. Currently, therapeutic strategies are limited and focus mainly on pain attenuation and maintaining joint functionality. First-line therapies are nonsteroidal anti-inflammatory drugs; in more advanced stages, stronger analgesics, such as opioids, are required, and in the most severe cases, joint arthroplasty is the only option to ensure joint mobility. Cannabinoids, both endocannabinoids and synthetic cannabinoid receptor (CB) agonists, are novel therapeutic options for the treatment of arthritis-associated pain. CB₁ receptors are mainly located in the nervous system; thus, CB₁ agonists induce many side effects, which limit their therapeutic efficacy. On the other hand, CB₂ receptors are mainly located in the periphery on immune cells, and CB₂ modulators exert analgesic and anti-inflammatory effects in vitro and in vivo. In the current review, novel research on the cannabinoid-mediated analgesic effect on arthritis is presented, with particular emphasis on the role of the CB₂ receptor in arthritis-related pain and the suppression of inflammation.

Efficacy of berberine in treatment of rheumatoid arthritis: From multiple targets to therapeutic potential

Rheumatoid arthritis is a systemic autoimmune disorder involved in persistent synovial inflammation. Berberine is a nature-derived alkaloid compound with multiple pharmacological activities in different pathologies, including RA. Recent experimental studies have clarified several determinant cellular and molecular targets of BBR in RA, and provided novel evidence supporting the promising therapeutic potential of BBR to combat RA. In this review, we recapitulate the therapeutic potential of BBR and its mechanism of action in ameliorating RA, and discuss the modulation of gut microbiota by BBR during RA. Collectively, BBR might be a promising lead drug with multi-functional activities for the therapeutic strategy of RA.

Shield and sword nano-soldiers ameliorate rheumatoid arthritis by multi-stage manipulation of neutrophils

Rheumatoid arthritis (RA) is characterized by the outbreak of inflammation. Neutrophils, the main culprit of the outbreak of inflammation, are the first inflammatory cells to be recruited to inflamed joints and facilitate the recruitment of themselves by stimulating the release of chemokines. Here, based on neutrophils, a novel anti-inflammatory "shield and sword soldiers" strategy is established with LMWH-TOS nanoparticles (LT NPs). The hydrophilic fragment low molecular weight heparin (LMWH) acts as a shield which block the transvascular movement of neutrophils through inhibiting the adhesion cascade by binding to P-selectin on inflamed endothelium. Synergistically, MMP-9, which is secreted by the recruited neutrophils and degrade the main component of articular cartilage, is reduced by the hydrophobic fragment d-α-tocopheryl succinate (TOS), functioning as a sword. In collagen-induced arthritis (CIA) mouse model, LT NPs show significant targeting effect, and exhibit prominent therapeutic efficacy after enveloping the first-line anti-RA drug methotrexate. Our work proves that the multi-stage manipulation of neutrophils is feasible and effective, providing a new concept for RA treatment.

Synoviolin is not a pathogenic factor for auto-inflammatory diseases

Auto-inflammatory syndromes are rare diseases characterized by arthritis and joint destruction, symptoms similar to but distinct from rheumatoid arthritis (RA). Therapeutic targets have not been well characterized for auto-inflammatory syndromes, although the E3 ligase Synoviolin was previously shown to be a novel therapeutic target for RA. Here, we show that Synoviolin loss has little impact on a model of auto-inflammatory diseases. We previously established such a model, the hIL-1 cTg mouse, in which IL-1 signaling was constitutively activated, and animals exhibit symptoms recapitulating auto-inflammatory syndromes such as major joint dominant arthritis. Here, we crossed hIL-1 cTg with Synoviolin flox'd mice to yield hIL-1 cTg/Synoviolin cKO mice. Synoviolin gene expression was ablated in adult hIL-1 cTg/Synoviolin cKO mice by injection of pIpC to activate Mx1 promoter-driven Cre recombinase. However, symptoms seen in hIL-1 cTg mice such as arthritis and joint destruction were not alleviated by targeting Synoviolin, ruling out Synoviolin as a therapeutic target for auto-inflammatory disease. Our results indicate that although similar, RA and auto-inflammatory diseases are different diseases, and treatment strategies should differ accordingly.

Inhibition of regulator of G protein signaling 10, aggravates rheumatoid arthritis progression by promoting NF-κB signaling pathway

Rheumatoid arthritis (RA) is the most common inflammatory arthropathy, with evidence pointing to an immune-mediated etiology that propagates chronic inflammation. Although targeted immune therapeutics and aggressive treatment strategies have substantially improved, a complete understanding of the associated pathological mechanisms of the disease remains elusive. This study aimed at investigating whether regulator of G protein signaling 10 (RGS10) could affect rheumatoid arthritis (RA) pathology by regulating the immune response. A DBA/J1 mouse model of RA was established and evaluated for disease severity. RGS10 expression was inhibited by adeno-associated virus in vivo. Moreover, small interfering RNA was used to downregulate RGS10 expression in raw 264.7 cells in vitro. Results showed that RGS10 inhibition augmented RA severity, and attenuated the increase in expression of inflammatory factors. Furthermore, activated NF-κB signaling pathways were detected following RGS10 inhibition. These results revealed that RGS10 inhibition directly aggravated the RA pathological process by activating the NF-κB signaling pathway. Therefore, RGS10 is a promising novel therapeutic target for RA treatment with a potential clinical impact.

The Immunomodulatory and Anti-Inflammatory Effect of Curcumin on Immune Cell Populations, Cytokines, and In Vivo Models of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a widespread chronic autoimmune disorder affecting the joints, causing irreversible cartilage, synovium, and bone degradation. During the course of the disease, many immune and joint cells are activated, causing inflammation. Immune cells including macrophages, lymphocytes, neutrophils, mast cells, natural killer cells, innate lymphoid cells, as well as synovial tissue cells, like fibroblast-like synoviocytes, chondrocytes, and osteoclasts secrete different proinflammatory factors, including many cytokines, angiogenesis-stimulating molecules and others. Recent studies reveal that curcumin, a natural dietary anti-inflammatory compound, can modulate the response of the cells engaging in RA course. This review comprises detailed data about the pathogenesis and inflammation process in rheumatoid arthritis and demonstrates scientific investigations about the molecular interactions between curcumin and immune cells responsible for rheumatoid arthritis development to discuss this herbal drug’s immunoregulatory role in RA treatment.

Nutrition and Rheumatoid Arthritis in the 'Omics' Era

Modern high-throughput 'omics' science tools (including genomics, transcriptomics, proteomics, metabolomics and microbiomics) are currently being applied to nutritional sciences to unravel the fundamental processes of health effects ascribed to particular nutrients in humans and to contribute to more precise nutritional advice. Diet and food components are key environmental factors that interact with the genome, transcriptome, proteome, metabolome and the microbiota, and this life-long interplay defines health and diseases state of the individual. Rheumatoid arthritis (RA) is a chronic autoimmune disease featured by a systemic immune-inflammatory response, in genetically susceptible individuals exposed to environmental triggers, including diet. In recent years increasing evidences suggested that nutritional factors and gut microbiome have a central role in RA risk and progression. The aim of this review is to summarize the main and most recent applications of 'omics' technologies in human nutrition and in RA research, examining the possible influences of some nutrients and nutritional patterns on RA pathogenesis, following a nutrigenomics approach. The opportunities and challenges of novel 'omics technologies' in the exploration of new avenues in RA and nutritional research to prevent and manage RA will be also discussed.

Microbiota-Derived Metabolites, Indole-3-aldehyde and Indole-3-acetic Acid, Differentially Modulate Innate Cytokines and Stromal Remodeling Processes Associated with Autoimmune Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation of the synovial joints. Inflammation, new blood vessel formation (angiogenesis) and bone resorption (osteoclastogenesis) are three key processes involved in the joint damage and deformities of arthritis. Various gut microbiota-derived metabolites are implicated in RA pathogenesis. However, there is barely any information about the impact of two such metabolites, indole-3-aldehyde (IAld) and indole-3-acetic acid (I3AA), on arthritis-related processes. We conducted a comparative analysis of IAld and I3AA using established cell-based models to understand how they might influence RA pathogenesis. Although structurally similar, the bioactivities of these two metabolites were profoundly different. IAld but not I3AA, inhibited the expression of pro-inflammatory cytokines (IL-1β and IL-6) in RAW 264.7 (RAW) cells stimulated with heat-killed M. tuberculosis sonicate (Mtb) and lipopolysaccharide (LPS). IAld also exhibited pro-angiogenic activity and pro-osteoclastogenic activity. In contrast, I3AA exhibited anti-angiogenic activity on endothelial cell tube formation but had no effect on osteoclastogenesis. Both IAld and I3AA have been proposed as aryl hydrocarbon receptor (AhR) agonists. Use of CH-223191, an inhibitor of the AhR, suppressed the anti-angiogenic activity of I3AA but failed to mitigate the effects of IAld. Further investigation of the anti-inflammatory activities of IAld and I3AA in LPS-treated RAW cells indicated that inhibition of MyD88-dependent activation of NF-κB and MAPK pathways was not likely involved. Our results suggest that the relative bioavailability of these indole derivatives may differentially impact RA progression and possibly other diseases that share similar cellular processes.

JAK Inhibitors and Modulation of B Cell Immune Responses in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic, systemic immune-mediated inflammatory disease that can lead to joint destruction, functional disability and substantial comorbidity due to the involvement of multiple organs and systems. B cells have several important roles in RA pathogenesis, namely through autoantibody production, antigen presentation, T cell activation, cytokine release and ectopic lymphoid neogenesis. The success of B cell depletion therapy with rituximab, a monoclonal antibody directed against CD20 expressed by B cells, has further supported B cell intervention in RA development. Despite the efficacy of synthetic and biologic disease modifying anti-rheumatic drugs (DMARDs) in the treatment of RA, few patients reach sustained remission and refractory disease is a concern that needs critical evaluation and close monitoring. Janus kinase (JAK) inhibitors or JAKi are a new class of oral medications recently approved for the treatment of RA. JAK inhibitors suppress the activity of one or more of the JAK family of tyrosine kinases, thus interfering with the JAK-Signal Transducer and Activator of Transcription (STAT) signaling pathway. To date, there are five JAK inhibitors (tofacitinib, baricitinib, upadacitinib, peficitinib and filgotinib) approved in the USA, Europe and/ or Japan for RA treatment. Evidence from the literature indicates that JAK inhibitors interfere with B cell functions. In this review, the main results obtained in clinical trials, pharmacokinetic, in vitro and in vivo studies concerning the effects of JAK inhibitors on B cell immune responses in RA are summarized.

Systemic pharmacological investigation of the Feng Shi Gu Tong capsule in the treatment of rheumatoid arthritis

Feng Shi Gu Tong (FSGT) capsule is a commonly used Chinese Traditional Patent Medicine in clinical practice, which has been proven to be effective for the treatment of active rheumatoid arthritis (RA). However, due to its complex composition, the precise molecular mechanism of the FSGT capsule in the treatment of RA is still indistinct. Therefore, the method of systemic pharmacology was used to obtain candidate compounds through absorption, distribution, metabolism, elimination (ADME) parameters, and supplementation of references. Network construction and analysis were also included to reveal the potential mechanism of FSGT capsule in treating RA. A total of 119 compounds were obtained in FSGT capsule, and a total of 107 compounds with targets were included in the study. These compounds acted on 267 targets in total. In addition, there were 317 targets related to RA disease. All constructed networks included four major networks and four minor networks. In addition, the clusters of RA disease protein-protein interaction (PPI) network and FSGT capsule-RA disease targets network revealed that the biological process involved in these clusters including immune response and apoptosis, etc. The pathways enriched by the direct targets of FSGT capsule acted on RA also highly overlapped with the pathways enriched by the RA PPI network, such as the TNF signaling pathway. Our research has managed to predict and explain the pharmacological effects and the molecular mechanisms of the FSGT capsule in RA, and provided a realistic exploration method for studying the potentially active ingredients of traditional Chinese medicines simultaneously.

Evolving concepts of the pathogenesis of rheumatoid arthritis with focus on the early and late stages

PURPOSE OF REVIEW

To provide an overview of recently published work covering key mechanisms involved in the pathogenesis of rheumatoid arthritis (RA), with focus on the early and late stages.

RECENT FINDINGS

Present understanding of RA pathogenesis has been mainly focused on the inflammatory process at the established phase of the disease, but recent work has shed light on important molecular and cellular mechanisms involved both at the early and late/refractory stages. In early RA, the involvement of anticitrullinated protein antibodies in RA induction has been identified with a critical role of the IL-23/Th17 axis in the control of their pathogenicity. At the late stage, RA may be viewed as a cell-autonomous genetic and epigenetic disease, characterized by altered cell death pathways in synoviocytes after long-term exposure to inflammation. An improved knowledge of these cell-intrinsic altered pathways is the basis for the targeting of pathogenic synoviocytes, as a new therapeutic alternative against resistance to current treatment targeting the immune system.

SUMMARY

We summarize these pathological pathways, and their understanding will facilitate the design of new diagnostic tools and therapeutic strategies combining the targeting of pathogenic synoviocytes with current immune-targeted therapies.

A novel loss-of-function mutation in LACC1 underlies hereditary juvenile arthritis with extended intra-familial phenotypic heterogeneity

OBJECTIVE

To investigate phenotypic and molecular characteristics of a consanguineous family with autosomal-recessive, polyarticular, juvenile idiopathic arthritis (JIA) with extra-articular manifestations, including renal amyloidosis and Crohn's disease, associated with a novel homozygous truncating variant in LACC1.

METHODS

Whole exome sequencing (WES) or targeted Sanger verification were performed in 15 participants. LACC1 expression and cytokine array were analyzed in patient-derived and CRISPR/Cas9-generated LACC1-knockout macrophages (Mϕ).

RESULTS

A homozygous truncating variant (p.Glu348Ter) in LACC1 was identified in three affected and one asymptomatic family member, and predicted harmful by causing premature stop of the LACC1 protein sequences, and by absence from ethnically-matched controls and public variation databases. Expression studies in patient-derived macrophages (Mϕ) showed no endogenous p. Glu348Ter-LACC1 RNA transcription or protein expression, compatible with nonsense-mediated mRNA decay. WES analysis in the asymptomatic homozygous subject for p. Glu348Ter-LACC1 detected an exclusive heterozygous variant (p.Arg928Gln) in complement component C5. Further complement activity analysis suggested a protective role for the p. Arg928Gln-C5 variant as a phenotypic modifier of LACC1-associated disease. Finally, cytokine profile analysis indicated increased levels of pro-inflammatory cytokines in LACC1-disrupted as compared with wild-type Mϕ.

CONCLUSIONS

Our findings reinforce the role of LACC1 disruption in autosomal-recessive JIA, extend the clinical spectrum and intra-familial heterogeneity of the disease-associated phenotype, indicate a modulatory effect of complement factor C5 on phenotypic severity, and suggest an inhibitory role for wild-type LACC1 on pro-inflammatory pathways.

Usefulness of Cytokine Gene Polymorphisms for the Therapeutic Choice in Japanese Patients with Rheumatoid Arthritis

Background

Rheumatoid arthritis (RA) is characterized by systemic synovitis with bone erosion and joint cartilage degradation. Although the analysis of polymorphisms in cytokine-encoding genes is important or understanding the pathophysiology of RA and selecting appropriate treatment for it, few studies have examined such single-nucleotide polymorphisms (SNPs) specifically in Japanese patients. This study was established to investigate the associations between polymorphisms in cytokine-encoding genes, autoantibodies and therapeutic responses in Japanese RA patients.

Methods

The subjects in this study consisted of 100 RA patients and 50 healthy controls. We extracted data on sex, age, disease duration, rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP) antibody, and therapeutic responses, including to methotrexate (MTX) and biological disease-modifying antirheumatic drugs (DMARDs). Genomic DNA was isolated from peripheral blood, which was genotyped for IL-10, TNF-α, TGF-β₁, and IFN-γ polymorphisms.

Results

Regarding IL-10 (−592 C/A and −819 C/T), significant decreases in the frequencies of the IL-10 (−592) CC genotype and (−819) CC genotype were found in RA patients compared with the levels in controls. For IFN-γ (+874 T/A), a significant decrease in the frequency of the TT genotype was found in RA patients compared with that in controls. Regarding TGF-β₁ (+869 T/C), patients with positivity for anti-CCP antibody had a significantly lower frequency of the CC genotype than those with negativity for it. Furthermore, the IL-10 (−592) CC genotype and (−819) CC genotype might be related to the biological DMARD-response.

Conclusion

Our results suggest that the analysis of polymorphisms in cytokine-encoding genes may be useful when selecting treatment for Japanese RA patients.

Molecular mechanism of the anti-inflammatory effects of Sophorae Flavescentis Aiton identified by network pharmacology

Inflammation, a protective response against infection and injury, involves a variety of biological processes. Sophorae Flavescentis (Kushen) is a promising Traditional Chinese Medicine (TCM) for treating inflammation, but the pharmacological mechanism of Kushen’s anti-inflammatory effect has not been fully elucidated. The bioactive compounds, predicted targets, and inflammation-related targets of Kushen were obtained from open source databases. The “Component-Target” network and protein–protein interaction (PPI) network were constructed, and hub genes were screened out by topological analysis. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed on genes in the PPI network. Furthermore, nitric oxide (NO) production analysis, RT-PCR, and western blot were performed to detect the mRNA and protein expression of hub genes in LPS-induced RAW264.7 cells. An immunofluorescence assay found that NF-κB p65 is translocated. A total of 24 bioactive compounds, 465 predicted targets, and 433 inflammation-related targets were identified and used to construct “Component-Targets” and PPI networks. Then, the five hub genes with the highest values-IL-6, IL-1β, VEGFA, TNF-α, and PTGS2 (COX-2)- were screened out. Enrichment analysis results suggested mainly involved in the NF-κB signaling pathway. Moreover, experiments were performed to verify the predicted results. Kushen may mediate inflammation mainly through the IL-6, IL-1β, VEGFA, TNF-α, and PTGS2 (COX-2), and the NF-κB signaling pathways. This finding will provide clinical guidance for further research on the use of Kushen to treat inflammation.

Interleukin-22 and connective tissue diseases: emerging role in pathogenesis and therapy

Interleukin-22 (IL-22), a member of the IL-10 family of cytokines, is produced by a number of immune cells involved in the immune microenvironment of the body. IL-22 plays its pivotal roles by binding to the IL-22 receptor complex (IL-22R) and subsequently activating the IL-22R downstream signalling pathway. It has recently been reported that IL-22 also contributes to the pathogenesis of many connective tissue diseases (CTDs). In this review, we will discuss the role of IL-22 in several CTDs, such as system lupus erythematosus, rheumatoid arthritis, Sjögren’s syndrome, systemic sclerosis and dermatomyositis, suggesting that IL-22 may be a potential therapeutic target in CTDs.

Periodontal pathogens alter the synovial proteome. Periodontal pathogens do not exacerbate macroscopic arthritis but alter the synovial proteome in mice

Rheumatoid arthritis (RA) and periodontitis (PD) are chronic inflammatory diseases that appear to occur in tandem. However, the mutual impact PD exerts on RA and vice versa has not yet been defined. To address this issue, we set up an animal model and analyzed how two prime inducers of periodontitis—Porphyromonas gingivalis (Pg) and Aggregatibacter actinomycetemcomitans (Aa)–differ in their pathogenic potential. Our experimental setup included collagen induced arthritis (CIA) in the mouse, oral inoculation with Pg or Aa to induce alveolar bone loss and the combination of both diseases in inverted orders of events. Neither pathobiont impacted on macroscopic arthritis and arthritis did not exacerbate alveolar bone loss. However, there were subtle differences between Pg and Aa with the former inducing more alveolar bone loss if PD was induced before CIA. On a molecular level, Pg and Aa led to differential expression patterns in the synovial membranes that were reminiscent of cellular and humoral immune responses, respectively. The Pg and Aa specific signatures in the synovial proteomes suggest a role for oral pathogens in shaping disease subtypes and setting the stage for subsequent therapy response.

[Rheumatic diseases and neuropathic pain : Diagnosis and treatment]

Pain is a leading symptom in inflammatory rheumatic diseases. For a long time it has been assumed that this pain is of nociceptive origin; however, in about one fifth of all patients the pain remains despite successful anti-inflammatory treatment and is not typically described as nociceptive by those affected. Recent studies indicate that some patients with rheumatoid arthritis (RA) experience pain with a neuropathic pain component. The treatment of neuropathic pain with damage to the somatosensory system differs markedly from the treatment of nociceptive pain in which the pain processing system is intact. Thus, the recognition and, above all, the more precise differentiation of the pain symptoms of affected patients make a decisive contribution to a successful treatment. With the help of a few points in the history and a physical examination, the assumption of the diagnosis neuropathic pain can often be rejected or substantiated. Pain with a neuropathic component does not adequately respond to typical analgesics. Instead, the high efficacy of co-analgesics, such as anticonvulsants and antidepressants, has been repeatedly proven.

The Roles of Matrix Metalloproteinases and Their Inhibitors in Human Diseases

Matrix metalloproteinases (MMPs) are a family of zinc-dependent extracellular matrix (ECM) remodeling endopeptidases that have the capacity to degrade almost every component of the ECM. The degradation of the ECM is of great importance, since it is related to embryonic development and angiogenesis. It is also involved in cell repair and the remodeling of tissues. When the expression of MMPs is altered, it can generate the abnormal degradation of the ECM. This is the initial cause of the development of chronic degenerative diseases and vascular complications generated by diabetes. In addition, this process has an association with neurodegeneration and cancer progression. Within the ECM, the tissue inhibitors of MMPs (TIMPs) inhibit the proteolytic activity of MMPs. TIMPs are important regulators of ECM turnover, tissue remodeling, and cellular behavior. Therefore, TIMPs (similar to MMPs) modulate angiogenesis, cell proliferation, and apoptosis. An interruption in the balance between MMPs and TIMPs has been implicated in the pathophysiology and progression of several diseases. This review focuses on the participation of both MMPs (e.g., MMP-2 and MMP-9) and TIMPs (e.g., TIMP-1 and TIMP-3) in physiological processes and on how their abnormal regulation is associated with human diseases. The inclusion of current strategies and mechanisms of MMP inhibition in the development of new therapies targeting MMPs was also considered.

British Journal of Biomedical Science in 2020. What have we learned?

Each year the British Journal of Biomedical Science publishes a 'What have we learned' editorial designed to introduce readers within the major disciplines of laboratory medicine to developments outside their immediate area. In addition it is designed to inform a wider readership of the advances in the diagnosis and treatment of disease. To this end, in 2020 the journal published 39 articles covering the disciplines within Biomedical Science in the 4 issues comprising volume 77. These included a review of COVID-19 in this issue, 27 original articles, 6 Biomedical Science 'In Brief' and 4 case histories. 27 of the articles involved molecular techniques, with one of these comparing results with a mass spectrometry based method. The preponderance of molecular genetic studies gives us a good idea of the likely future direction of the disciplines.

Construction of CII-Specific CAR-T to Explore the Cytokine Cascades Between Cartilage-Reactive T Cells and Chondrocytes

Cytokine cascades exist in many autoimmune disorders which amplify and sustain the autoimmune process and lead to chronic inflammatory injury to the host tissues. Increasing evidence indicates that chondrocytes can interact with T cells, which may be a crucial event in inflammatory arthritis. To address the reciprocal influences of cartilage-reactive T cells and chondrocytes, we constructed cartilage-reactive T cells by developing a type II collagen-specific chimeric antigen receptor (CII-CAR). An in vitro co-culture model of CII-CAR-T cells and fresh cartilage was developed, in which CII-CAR-T displayed specific proliferative capacity and cytokine release against fresh cartilage samples, and chondrocytes could respond to CII-CAR-T cells by secreting IL-6. The proposed model will help us to explore the possible cytokine cascades between cartilage-reactive T cells and cartilage.

Aberrant expression of USF2 in refractory rheumatoid arthritis and its regulation of proinflammatory cytokines in Th17 cells

IL-17-producing Th17 cells are implicated in the pathogenesis of rheumatoid arthritis (RA) and TNF-α, a proinflammatory cytokine in the rheumatoid joint, facilitates Th17 differentiation. Anti-TNF therapy ameliorates disease in many patients with rheumatoid arthritis (RA). However, a significant proportion of patients do not respond to this therapy. The impact of anti-TNF therapy on Th17 responses in RA is not well understood. We conducted high-throughput gene expression analysis of Th17-enriched CCR6+CXCR3-CD45RA- CD4+ T (CCR6+ T) cells isolated from anti-TNF-treated RA patients classified as responders or nonresponders to therapy. CCR6+ T cells from responders and nonresponders had distinct gene expression profiles. Proinflammatory signaling was elevated in the CCR6+ T cells of nonresponders, and pathogenic Th17 signature genes were up-regulated in these cells. Gene set enrichment analysis on these signature genes identified transcription factor USF2 as their upstream regulator, which was also increased in nonresponders. Importantly, short hairpin RNA targeting USF2 in pathogenic Th17 cells led to reduced expression of proinflammatory cytokines IL-17A, IFN-γ, IL-22, and granulocyte-macrophage colony-stimulating factor (GM-CSF) as well as transcription factor T-bet. Together, our results revealed inadequate suppression of Th17 responses by anti-TNF in nonresponders, and direct targeting of the USF2-signaling pathway may be a potential therapeutic approach in the anti-TNF refractory RA.

Aqueous Extract of Kan-Lu-Hsiao-Tu-Tan Ameliorates Collagen-Induced Arthritis in Mice by Inhibiting Oxidative Stress and Inflammatory Responses

Background: Kan-Lu-Hsiao-Tu-Tan (KLHTT) exhibits anti-psoriatic effects through anti-inflammatory activity in mice. However, the therapeutic effects of KLHTT on rheumatoid arthritis (RA), another significant autoimmune inflammatory disorder, have not been elucidated. Herein, we explored the anti-arthritic effects of KLHTT on collagen-induced arthritis (CIA) in mice. Methods: KLHTT was extracted by boiling water and subjected to spectroscopic analysis. Chicken collagen type II (CII) with complete Freund’s adjuvant was intradermally injected to induce CIA in DBA/1J mice. Anti-CII antibody, cytokines, malondialdehyde (MDA), and hydrogen peroxide (H₂O₂) were measured using ELISA, thiobarbituric acid reactive substances, and a hydrogen peroxide assay kit. Splenocyte proliferation was tested using thymidine incorporation. Th1 and Th17 cells were analyzed by flow cytometry. Results: Oral KLHTT treatment (50 and 100 mg/kg) ameliorated mouse CIA by decreasing the levels of interleukin (IL)-1β, IL-6, IL-17A, and tumour necrosis factor-α in the paw homogenates and serum. KLHTT also suppressed anti-CII antibody formation, splenocyte proliferation, and splenic Th1 and Th17 cell numbers. Additionally, KLHTT showed antioxidant activity by reducing the concentrations of MDA and H₂O₂ in paw tissues. Conclusions: The therapeutic effects of KLHTT in CIA mice were through regulating oxidative stress and inflammatory responses. Our results suggest that KLHTT has potential to treat RA.

Roles of MicroRNAs in Bone Destruction of Rheumatoid Arthritis

As an important pathological result of rheumatoid arthritis (RA), bone destruction will lead to joint injury and dysfunction. The imbalance of bone metabolism caused by increased osteoclast activities and decreased osteoblast activities is the main cause of bone destruction in RA. MicroRNAs (MiRNAs) play an important role in regulating bone metabolic network. Recent studies have shown that miRNAs play indispensable roles in the occurrence and development of bone-related diseases including RA. In this paper, the role of miRNAs in regulating bone destruction of RA in recent years, especially the differentiation and activities of osteoclast and osteoblast, is reviewed. Our results will not only help provide ideas for further studies on miRNAs’ roles in regulating bone destruction, but give candidate targets for miRNAs-based drugs research in bone destruction therapy of RA as well.

Tailoring biologic therapy for real-world rheumatoid arthritis patients

Introduction: The cornerstone of rheumatoid arthritis (RA) therapy relies on the treat-to-target strategy, which aims at dampening inflammation as soon as possible in order to achieve persistent low disease activity or, ideally, remission, according to validated disease activity measures. Traditional disease-modifying antirheumatic drugs (DMARDs) may be chosen in monotherapy or in combination as first-line therapy; in case of an unsatisfactory response after a 3-6-month trial, biologic therapy may be commenced.Areas covered: Real-life RA patients may present with concomitant comorbidities/complications or be in peculiar physiological states which raise more than one question as to which biotherapy may be more well suited considering the whole clinical picture. Therefore, a thorough literature search was performed to identify the most appropriate biologic therapy in each setting considered in this review.Expert opinion: Here we provide suggestions for the use of biologic drugs having a predictable better outcome in specific real-world conditions, so as to ideally profile the patient to the best of the current knowledge.

Activation of c-Jun N-Terminal Kinase, a Potential Therapeutic Target in Autoimmune Arthritis

The c-Jun-N-terminal kinase (JNK) is a critical mediator involved in various physiological processes, such as immune responses, and the pathogenesis of various diseases, including autoimmune disorders. JNK is one of the crucial downstream signaling molecules of various immune triggers, mainly proinflammatory cytokines, in autoimmune arthritic conditions, mainly including rheumatoid arthritis, ankylosing spondylitis, and psoriatic arthritis. The activation of JNK is regulated in a complex manner by upstream kinases and phosphatases. Noticeably, different subtypes of JNKs behave differentially in immune responses. Furthermore, aside from biologics targeting proinflammatory cytokines, small-molecule inhibitors targeting signaling molecules such as Janus kinases can act as very powerful therapeutics in autoimmune arthritis patients unresponsiveness to conventional synthetic antirheumatic drugs. Nevertheless, despite these encouraging therapies, a population of patients with an inadequate therapeutic response to all currently available medications still remains. These findings identify the critical signaling molecule JNK as an attractive target for investigation of the immunopathogenesis of autoimmune disorders and for consideration as a potential therapeutic target for patients with autoimmune arthritis to achieve better disease control. This review provides a useful overview of the roles of JNK, how JNK is regulated in immunopathogenic responses, and the potential of therapeutically targeting JNK in patients with autoimmune arthritis.

[Proinflammatory cytokines and cardio-vascular risk: From myocardial infarction tocytokine storm of COVID-19]

The mechanisms of inflammatory diseases involve the key inflammatory cytokines IL-1, TNF, IL-6, and IL-17 which are now therapeutic targets with biotherapies. They contribute to the local manifestations of clinically different diseases. In addition to these local aspects, these cytokines have systemic effects from their action on the liver, muscle, adipose tissue and the cardiovascular system. All these diseases have in common an increase in cardiovascular risk. In the general population, the same concepts are applicable, as shown by the link between an even modest rise in CRP and cardiovascular risk. More recently, the cytokine storm of severe forms of COVID-19 has shown that synergistic interactions between cytokines first described in vitro are further amplified in the clinical picture with multiple and severe impairment of key organs. In these chronic and acute contexts, control of inflammation by targeting cytokines is a new vascular treatment option, with already important results for IL-1.

Role of signaling pathway in biological cause of Rheumatoid arthritis

Rheumatoid Arthritis is a chronic progressive inflammatory auto-immune disease in which the immune system of the body attacks its cartilage and joints lining. It not only affects synovial joints but also many other sites including heart, blood vessels, and skins. It is more common in females than in males. The exact cause of rheumatoid arthritis is not well established but the hypothesis reported in the literature is that in the development stage of the disease, both genetics and environmental factors can play an inciting role. Along with these factors alteration in the normal physiology of enzymatic action, acts as a trigger to develop this condition. Numerous signaling pathways involved in the pathogenesis of Rheumatoid Arthritis involves activation of mitogen-activated protein kinase, kinases Janus family, P-38 Mitogen-Activated Protein Kinase, Nuclear Factor-kappa B. Interleukin-1 to play a proinflammatory cytokine that plays an important role in inflammation in RA. These are also associated with an increase in neutrophil, macrophage and lymphocytic chemotaxis, mast cell degranulation, activation, maturation and survival of T-cells and B-cells activated. These signaling pathways also show that p38α downregulation in myeloid cells exacerbates the severity of symptoms of arthritis. Thus, present review carters about the detail of different signaling pathways and their role in rheumatoid arthritis.

Distinct Tissue Damage and Microbial Cues Drive Neutrophil and Macrophage Recruitment to Thermal Injury

Tissue damage triggers a rapid innate immune response that mediates host defense. Previously we reported that thermal damage of the larval zebrafish fin disrupts collagen organization and induces a robust and potentially damaging innate immune response. The mechanisms that drive damaging versus protective neutrophil inflammation in interstitial tissues remain unclear. Here we identify distinct cues in the tissue microenvironment that differentially drive neutrophil and macrophage responses to sterile injury. Using live imaging, we found a motile zone for neutrophils, but not macrophages, in collagen-free regions and identified a specific role for interleukin-6 (IL-6) receptor signaling in neutrophil responses to thermal damage. IL-6 receptor mutants show impaired neutrophil recruitment to sterile thermal injury that was not present in tissues infected with Pseudomonas aeruginosa. These findings identify distinct signaling networks during neutrophil recruitment to sterile and microbial damage cues and provide a framework to limit potentially damaging neutrophil inflammation.

IL-18: a suggested target for immunomodulation in chikungunya virus infection

Chronic joint pain is the most common pathology found in chikungunya virus (CHIKV)-infected patients. Eight cytokines were compared in CHIKV patients with and without joint pain. IL-4 and IL-13 levels were significantly lower in patients with joint pain (p = 0.006 and p < 0.0001, respectively). IL-18 levels were higher in the group of patients with joint pain (p < 0.0001) and were significantly higher on days 3 and 4 after onset (p = 0.0012 and p = 0.003, respectively). Moreover, TNF-α levels were significantly higher in patients with joint pain on day 3 (p = 0.028). This study demonstrated that cytokines, particularly IL-18, may be candidates for immunomodulation.

Neutral sphingomyelinase 2 regulates inflammatory responses in monocytes/macrophages induced by TNF-α

Obesity is associated with elevated levels of TNF-α and proinflammatory CD11c monocytes/macrophages. TNF-α mediated dysregulation in the plasticity of monocytes/macrophages is concomitant with pathogenesis of several inflammatory diseases, including metabolic syndrome, but the underlying mechanisms are incompletely understood. Since neutral sphingomyelinase-2 (nSMase2: SMPD3) is a key enzyme for ceramide production involved in inflammation, we investigated whether nSMase2 contributed to the inflammatory changes in the monocytes/macrophages induced by TNF-α. In this study, we demonstrate that the disruption of nSMase activity in monocytes/macrophages either by chemical inhibitor GW4869 or small interfering RNA (siRNA) against SMPD3 results in defects in the TNF-α mediated expression of CD11c. Furthermore, blockage of nSMase in monocytes/macrophages inhibited the secretion of inflammatory mediators IL-1β and MCP-1. In contrast, inhibition of acid SMase (aSMase) activity did not attenuate CD11c expression or secretion of IL-1β and MCP-1. TNF-α-induced phosphorylation of JNK, p38 and NF-κB was also attenuated by the inhibition of nSMase2. Moreover, NF-kB/AP-1 activity was blocked by the inhibition of nSMase2. SMPD3 was elevated in PBMCs from obese individuals and positively corelated with TNF-α gene expression. These findings indicate that nSMase2 acts, at least in part, as a master switch in the TNF-α mediated inflammatory responses in monocytes/macrophages.

Novel Approaches to Target Mutant FLT3 Leukaemia

Simple Summary

Acute myeloid leukemia (AML) is a haematologic disease in which oncogenic mutations in the receptor tyrosine kinase FLT3 frequently lead to leukaemic development. Potent treatment of AML patients is still hampered by inefficient targeting of leukemic stem cells expressing constitutive active FLT3 mutants. This review summarizes the current knowledge about the regulation of FLT3 activity at cellular level and discusses therapeutical options to affect the tumor cells and the microenvironment to impair the haematological aberrations.

Abstract

Fms-like tyrosine kinase 3 (FLT3) is a member of the class III receptor tyrosine kinases (RTK) and is involved in cell survival, proliferation, and differentiation of haematopoietic progenitors of lymphoid and myeloid lineages. Oncogenic mutations in the FLT3 gene resulting in constitutively active FLT3 variants are frequently found in acute myeloid leukaemia (AML) patients and correlate with patient’s poor survival. Targeting FLT3 mutant leukaemic stem cells (LSC) is a key to efficient treatment of patients with relapsed/refractory AML. It is therefore essential to understand how LSC escape current therapies in order to develop novel therapeutic strategies. Here, we summarize the current knowledge on mechanisms of FLT3 activity regulation and its cellular consequences. Furthermore, we discuss how aberrant FLT3 signalling cooperates with other oncogenic lesions and the microenvironment to drive haematopoietic malignancies and how this can be harnessed for therapeutical purposes.

Clinical and Laboratory Associations with Methotrexate Metabolism Gene Polymorphisms in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease that causes loss of joint function and significantly reduces quality of life. Plasma metabolite concentrations of disease-modifying anti-rheumatic drugs (DMARDs) can influence treatment efficacy and toxicity. This study explored the relationship between DMARD-metabolising gene variants and plasma metabolite levels in RA patients. DMARD metabolite concentrations were determined by tandem mass-spectrometry in plasma samples from 100 RA patients with actively flaring disease collected at two intervals. Taqman probes were used to discriminate single-nucleotide polymorphism (SNP) genotypes in cohort genomic DNA: rs246240 (ABCC1), rs1476413 (MTHFR), rs2231142 (ABCG2), rs3740065 (ABCC2), rs4149081 (SLCO1B1), rs4846051 (MTHFR), rs10280623 (ABCB1), rs16853826 (ATIC), rs17421511 (MTHFR) and rs717620 (ABCC2). Mean plasma concentrations of methotrexate (MTX) and MTX-7-OH metabolites were higher (p < 0.05) at baseline in rs4149081 GA genotype patients. Patients with rs1476413 SNP TT or CT alleles have significantly higher (p < 0.001) plasma poly-glutamate metabolites at both study time points and correspondingly elevated disease activity scores. Patients with the rs17421511 SNP AA allele reported significantly lower pain scores (p < 0.05) at both study intervals. Genotyping strategies could help prioritise treatments to RA patients most likely to gain clinical benefit whilst minimizing toxicity.

IL-6 promotes collagen-induced arthritis by activating the NLRP3 inflammasome through the cathepsin B/S100A9-mediated pathway

Rheumatoid arthritis (RA) is an inflammatory disease with symmetric polyarthritis. IL-6 and NLRP3 inflammasome in macrophages contribute to the pathogenesis of RA. This study aimed to investigate the relationship between IL-6 and the NLRP3 inflammasome in RA. Here, we found that IL-6 inhibition reduced NLRP3 inflammasome activation in mice with collage-induced arthritis (CIA). In vitro studies showed that IL-6 directly induced NLRP3 inflammasome activation via cathepsin B (CTSB) in the presence of ATP. In addition, S100A9 induced by ATP stimulation promoted the interaction of CTSB and NLRP3 to activate the NLRP3 inflammasome. Our findings show a novel mechanism of NLRP3 inflammasome activation by IL-6 that may lead to a potential therapy for RA by interrupting the interaction between IL-6 and the NLRP3 inflammasome.

Significance of serum albumin and derived neutrophil-to-lymphocyte ratio score in assessment of disease activity in rheumatoid arthritis patients

Background

Albumin and derived neutrophil to lymphocyte ratio (dNLR) are known biomarkers that can reflect systemic inflammation and it has been hypothesized that combination of both markers in one score (albumin-dNLR score) can be useful in monitoring rheumatoid arthritis (RA) patients. The current study intended to measure albumin -dNLR score in patients with RA in the order to find whether these new biomarkers could reflect the activity of the disease and the articular activity detected by ultrasonography. We measured serum albumin and dNLR in blood samples obtained from 100 RA patients and from 100 apparently healthy controls (HC). Albumin -dNLR score was calculated according to the presence of hypoalbuminemia (≤ 3.76 gm/dl) and/or raised dNLR (>1.37).

Results

RA patients had a significantly elevated dNLR (p< 0.001) and albumin-dNLR score (p< 0.001) compared to their levels in HC, while serum albumin was significantly decreased (p< 0.001) in RA patients than its level in HC. In RA patients, albumin-dNLR score correlated significantly with DAS28 (p< 0.001), erythrocyte sedimentation rate (ESR) (p< 0.001), C-reactive protein (p< 0.001), grey scale (p< 0.001), power Doppler (p< 0.001) and total ultrasound score (p< 0.001). Also, tender joint count, ESR and albumin-dNLR score were significant predictors of DAS28 in multivariate regression analysis.

Conclusions

Our study settled that albumin - dNLR score is increased in RA patients than in healthy subjects. The score correlated well with DAS28, acute phase reactants, and ultrasonographic synovitis scores implying that it could be an easy valuable biomarker to monitor RA disease activity.

Synergistic Interaction Between High Bioactive IL-17A and Joint Destruction for the Occurrence of Cardiovascular Events in Rheumatoid Arthritis

Rheumatoid arthritis (RA) remains a cause of morbidity and mortality in many patients while new treatments have changed the face of the disease. Despite the emergence of these new drugs, cardiovascular (CV) diseases remain more frequent in RA patients compared with the general population. However, predictive biomarkers of RA severity and precise guidelines to manage the CV risk in these patients are still lacking. Pro-inflammatory cytokines contribute both to RA and CV pathogenesis. Focusing on IL-17A, high levels of bioactive IL-17A were associated with destruction in RA but also during myocardial infarction. The study aimed to assess the relationship between bioactive IL-17A, destruction and the occurrence of CV events (CVE) in RA patients with a very long follow-up. Thirty-six RA patients were followed between 1970 and 2012 in Lyon, France. They were tested for bioactive IL-17A and clinical and biological characteristics were recorded at baseline. Then, the occurrence of CVE was registered during the follow-up. To study the bioactive fraction of IL-17A, the bioassay used the ability of human umbilical vein endothelial cells to produce IL-8 in presence of RA plasma samples with or without an anti-IL-17A antibody. Bioactive IL-17A level at baseline was higher in RA patients who later experienced a CVE compared to those without (0.77 vs 0.21 ng/ml, p-value = 0.0095, Mann-Whitney test) and synergized with joint destruction (p-value = 0.020, Kruskal-Wallis test). Through its effects on vessels and thrombosis, high levels of bioactive IL-17A could represent a long-term marker of CV risk.

Chebulanin exerts its anti-inflammatory and anti-arthritic effects via inhibiting NF-κB and MAPK activation in collagen-induced arthritis mice

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease characterized by synovial inflammation and progressive joint destruction. Chebulanin is a natural polyphenol acid isolated from the traditional Tibetan medicine Terminalia chebula Retz that has previously been reported to possess anti-inflammatory properties. The present study aimed to investigate the anti-inflammatory and anti-arthritic effects of chebulanin and explore its underlying mechanisms in vivo and in vitro using a collagen-induced arthritis (CIA) mouse model and lipopolysaccharide (LPS) stimulated RAW264.7 cell inflammation model. Arthritis severity scores were assessed twice weekly; the levels of cytokines interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in serum were detected using enzyme-linked immunosorbent assay kits; histopathological assessment was performed using micro computed tomography and hematoxylin and eosin staining. Activation of nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways were assessed using western blotting. The inhibition of translocation of cytosolic p38 and p65 into the nucleus was observed using immunofluorescence staining and western blotting in vitro. Chebulanin significantly suppressed the progression and development of RA in CIA mice by decreasing the arthritis severity scores, attenuating paw swelling and joint destruction, and reducing the levels of IL-6 and TNF-α significantly (p < 0.05). Furthermore, chebulanin reduced the levels of excised phosphorylated (p)-p38, phosphorylated-c-JUN N-terminal kinase (p-JNK), p-p65 and phosphorylated NF-κB inhibitor alpha (p-IκBα) in CIA mice, but did not affect the level of phosphorylated extracellular-signal-regulated kinase (ERK). In addition, chebulanin could inhibit the nuclear translocation of p38 and p65 in LPS-stimulated macrophages in dose-dependent manner. In conclusion, this study demonstrated that chebulanin exerts anti-inflammatory and anti-arthritic effects by inhibiting the activation of NF-κB and MAPK signaling pathways.

Serum levels of 14-3-3η are associated with increased disease risk, activity and duration of rheumatoid arthritis in Chinese patients

The aim of the present study was to determine the association between serum 14-3-3η expression levels and disease risk, inflammation level and disease duration in Chinese patients with rheumatoid arthritis (RA). A total of 45 Chinese patients with RA, 45 patients with osteoarthritis (OA) and 44 age- and sex-matched (with the RA group) healthy control (HC) subjects were consecutively recruited for the present case-controlled study. In addition, the demographic and clinicopathological characteristics of the patients with RA were collected. Serum samples were obtained from patients with RA, patients with OA and the HCs, and the serum levels of 14-3-3η were determined by ELISA. Compared with that in the OA patients (P=0.006) and HCs (P<0.001), 14-3-3η expression was significantly increased in RA patients, and receiver operating characteristics (ROC) analysis indicated that it served as a potential predictive marker for the risk of RA. In patients with RA, serum levels of 14-3-3η were positively correlated with disease duration (P=0.003), erythrocyte sedimentation rate (P=0.006) and disease activity score in 28 joints (P=0.025). The proportion of rheumatoid factor (RF)-positive patients (P=0.023) and anti-citrullinated protein antibody (ACPA)-positive patients (P=0.002) with RA was increased (when 14-3-3η expression was increased) compared with RF-negative patients or ACPA-negative patients, respectively. Of note, 14-3-3η serum levels were able to distinguish patients with established RA (disease duration, >2 years) from patients with early RA (disease duration, ≤2 years) with an AUC of 0.759 (95% CI, 0.612-0.905), and the sensitivity and the specificity at the best cut-off point (14-3-3η=0.613 ng/ml) were 79.3 and 75.0%, respectively. Furthermore, 14-3-3η was able to differentiate between RF-positive RA patients and RF-negative patients or HCs. In conclusion, circulating 14-3-3η expression may serve as a novel biomarker for disease risk and activity of RA in Chinese patients.

Interleukin-6 in Rheumatoid Arthritis

The role of interleukin (IL)-6 in health and disease has been under a lot of scrutiny in recent years, particularly during the recent COVID-19 pandemic. The inflammatory pathways in which IL-6 is involved are also partly responsible of the development and progression of rheumatoid arthritis (RA), opening interesting perspectives in terms of therapy. Anti-IL-6 drugs are being used with variable degrees of success in other diseases and are being tested in RA. Results have been encouraging, particularly when anti-IL-6 has been used with other drugs, such as metothrexate (MTX). In this review we discuss the main immunologic aspects that make anti-IL-6 a good candidate in RA, but despite the main therapeutic options available to target IL-6, no gold standard treatment has been established so far.

The IL-1 family cytokines and receptors in autoimmune diseases

The role of the cytokines and receptors of the IL-1 family in inflammation is well known. Several cytokines of the family have a powerful inflammatory activity, with IL-1β being the best-characterized factor. The inflammatory activity of IL-1 cytokines is regulated by other factors of the family, including receptor antagonists, soluble receptors and anti-inflammatory cytokines. The causative role of IL-1β is well-established in autoinflammatory diseases, mainly due to gain-of-function mutations in genes encoding the IL-1β-maturing inflammasome. Exaggerated production of IL-1β and IL-18 correlates with disease and disease severity also in several autoimmune and chronic inflammatory and degenerative pathologies, although it is not clear whether they have a causative role or are only involved in the downstream disease symptoms. A better understanding of the pathological role of IL-1 family cytokines in autoimmunity involves a deeper evaluation, in the pathological situations, of the possible anomalies in the feed-back anti-inflammatory mechanisms that in physiological reactions control and dump IL-1-mediated inflammation. Thus, we expect that IL-1 cytokines may be pathogenic only when, in addition to enhanced production, there is a concomitant failure of their control mechanisms. In this review we will examine the current knowledge on the role of IL-1 family cytokines in autoimmune and chronic inflammatory and degenerative diseases, with a particular focus on their endogenous control mechanisms, mainly based on soluble receptors/inhibitors and receptor antagonists. This will allow us to formulate a knowledge-based hypothesis on the involvement of IL-1 cytokines in the pathogenesis vs. the clinical features of these diseases.

Network pharmacology and molecular docking analysis on molecular targets and mechanisms of Huashi Baidu formula in the treatment of COVID-19

Purpose

Huashi Baidu formula (HSBDF) was developed to treat the patients with severe COVID-19 in China. The purpose of this study was to explore its active compounds and demonstrate its mechanisms against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) through network pharmacology and molecular docking.

Methods

All the components of HSBDF were retrieved from the pharmacology database of TCM system. The genes corresponding to the targets were retrieved using UniProt and GeneCards database. The herb–compound–target network was constructed by Cytoscape. The target protein–protein interaction network was built using STRING database. The core targets of HSBDF were analyzed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). The main active compounds of HSBDF were docked with SARS-CoV-2 and angiotensin converting enzyme II (ACE2).

Results

Compound–target network mainly contained 178 compounds and 272 corresponding targets. Key targets contained MAPK3, MAPK8, TP53, CASP3, IL6, TNF, MAPK1, CCL2, PTGS2, etc. There were 522 GO items in GO enrichment analysis (p < .05) and 168 signaling pathways (p < .05) in KEGG, mainly including TNF signaling pathway, PI3K–Akt signaling pathway, NOD-like receptor signaling pathway, MAPK signaling pathway, and HIF-1 signaling pathway. The results of molecular docking showed that baicalein and quercetin were the top two compounds of HSBDF, which had high affinity with ACE2.

Conclusion

Baicalein and quercetin in HSBDF may regulate multiple signaling pathways through ACE2, which might play a therapeutic role on COVID-19.

Cell death in chronic inflammation: breaking the cycle to treat rheumatic disease

Cell death is a vital process that occurs in billions of cells in the human body every day. This process helps maintain tissue homeostasis, supports recovery from acute injury, deals with infection and regulates immunity. Cell death can also provoke inflammatory responses, and lytic forms of cell death can incite inflammation. Loss of cell membrane integrity leads to the uncontrolled release of damage-associated molecular patterns (DAMPs), which are normally sequestered inside cells. Such DAMPs increase local inflammation and promote the production of cytokines and chemokines that modulate the innate immune response. Cell death can be both a consequence and a cause of inflammation, which can be difficult to distinguish in chronic diseases. Despite this caveat, excessive or poorly regulated cell death is increasingly recognized as a contributor to chronic inflammation in rheumatic disease and other inflammatory conditions. Drugs that inhibit cell death could, therefore, be used therapeutically for the treatment of these diseases, and programmes to develop such inhibitors are already underway. In this Review, we outline pathways for the major cell death programmes (apoptosis, necroptosis, pyroptosis and NETosis) and their potential roles in chronic inflammation. We also discuss current and developing therapies that target the cell death machinery.