Inhibition of Janus kinase/signal transducer and activator of transcription (JAK/STAT) signalling pathway in rheumatoid synovial fibroblasts using small molecule compounds

Estragole Ameliorates CFA Induced Rheumatoid Arthritis Symptoms in Wistar Rats by Inhibiting JAK-2/STAT-3 Pathway

The present study was conducted to scrutinize the pharmacological effect of Estragole (ESG) against CFA-induced arthritis in rats. The rats underwent induction of arthritis using the administration of CFA and after that, the rats were randomly divided into five different groups, where three groups correspond to diverse dosages of ESG, and the other two were control and CFA-arthritic control. Results of the study suggested that ESG in a dose-dependent manner, improves body weight and arthritis score of rats as evidenced by reduction of hind-paw volume. ESG also improved the antioxidant status of rats by reducing MDA levels and enhancing the concentration of endogenous antioxidants SOD and GPx. The level of pro-inflammatory cytokines was also found to be reduced in the case of ESG treated group as compared to CFA-group. In a western blot analysis, ESH showed downregulation of p-JAK-2/STAT-3. The study provided concrete evidence for the protective effect of ESG against rheumatoid arthritis in rats.

Antibodies of the immunoglobulin a isotype to novel antigens in early axial spondyloarthritis

Introduction

There is an unmet need for biomarkers to identify patients with axial spondyloarthritis (axSpA). Increasing evidence suggest the presence of autoantibodies in a subset of axSpA patients. The aim of this study was to identify novel IgA antibodies in early axSpA patients and to determine their diagnostic potential in combination with previously determined IgG antibodies against UH (Hasselt University)-axSpA-IgG antigens.

Methods

An axSpA cDNA phage display library constructed from axSpA hip synovium, was used to screen for novel IgA antibodies in plasma from early axSpA patients. The presence of these antibodies against novel UH-axSpA-IgA antigens was determined in two independent axSpA cohorts, in healthy controls and in patients with chronic low back pain.

Results

We identified antibodies to 7 novel UH-axSpA-IgA antigens, of which 6 correspond to non-physiological peptides and 1 to the human histone deacetylase 3 (HDAC3) protein. IgA antibodies against 2 of these 7 novel UH-axSpA-IgA antigens and IgG antibodies against 2 of the previously identified antigens were significantly more present in early axSpA patients from the UH cohort (18/70, 25.7%) and the (Bio)SPAR cohort (26/164, 15.9%), compared to controls with chronic low back pain (2/66, 3%). Antibodies to this panel of 4 antigens were present in 21.1% (30/142) of patients with early axSpA from the UH and (Bio)SPAR cohorts. The positive likelihood ratio for confirming early axSpA using antibodies to these 4 UH-axSpA antigens was 7.0. So far, no clinical correlation between the novel identified IgA antibodies and inflammatory bowel disease could be identified.

Discussion

In conclusion, screening an axSpA cDNA phage display library for IgA reactivity resulted in the identification of 7 novel UH-axSpA-IgA antigens, of which 2 show promising biomarker potential for the diagnosis of a subset of axSpA patients, in combination with previously identified UH-axSpA-IgG antigens.

Tofacitinib blocks IFN-regulated biomarker genes in skin fibroblasts and keratinocytes in a systemic sclerosis trial

BACKGROUNDSystemic sclerosis (SSc) is an autoimmune, connective tissue disease characterized by vasculopathy and fibrosis of the skin and internal organs.METHODSWe randomized 15 participants with early diffuse cutaneous SSc to tofacitinib 5 mg twice a day or matching placebo in a phase I/II double-blind, placebo-controlled trial. The primary outcome measure was safety and tolerability at or before week 24. To understand the changes in gene expression associated with tofacitinib treatment in each skin cell population, we compared single-cell gene expression in punch skin biopsies obtained at baseline and 6 weeks following the initiation of treatment.RESULTSTofacitinib was well tolerated; no participants experienced grade 3 or higher adverse events before or at week 24. Trends in efficacy outcome measures favored tofacitnib. Baseline gene expression in fibroblast and keratinocyte subpopulations indicated IFN-activated gene expression. Tofacitinib inhibited IFN-regulated gene expression in SFRP2/DPP4 fibroblasts (progenitors of myofibroblasts) and in MYOC/CCL19, representing adventitial fibroblasts (P < 0.05), as well as in the basal and keratinized layers of the epidermis. Gene expression in macrophages and DCs indicated inhibition of STAT3 by tofacitinib (P < 0.05). No clinically meaningful inhibition of T cells and endothelial cells in the skin tissue was observed.CONCLUSIONThese results indicate that mesenchymal and epithelial cells of a target organ in SSc, not the infiltrating lymphocytes, may be the primary focus for therapeutic effects of a Janus kinase inhibitor.TRIAL REGISTRATIONClinicalTrials.gov NCT03274076.FUNDINGPfizer, NIH/National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) R01 AR070470, NIH/NIAMS K24 AR063120, Taubman Medical Research Institute and NIH P30 AR075043, and NIH/NIAMS K01 AR072129.

Aconiti lateralis radix praeparata total alkaloids exert anti-RA effects by regulating NF-κB and JAK/STAT signaling pathways and promoting apoptosis

Aconiti Lateralis Radix Praeparata (“Fuzi” in Chinese) is one of the traditional herbs widely used to intervene rheumatoid arthritis (RA), while Fuzi total alkaloids (FTAs) are the main bioactive components. However, the treatment targets and specific mechanisms of FTAs against RA have not been fully elucidated. The purpose of the present study was to confirm the anti-rheumatism effects of FTAs and reveal its potential molecular mechanisms. In TNF-α-induced MH7A cells model, we found that FTAs showed inhibitory effects on proliferation. While, FTAs significantly decreased the expression levels of IL-1β, IL-6, MMP-1, MMP-3, PGE2, TGF-β, and VEGF. FTAs also enhanced the progress of apoptosis and arrested the cell cycle at G0/G1 phase to prevent excessive cell proliferation. In addition, FTAs inhibited the hyperactivity of NF-κB and JAK/STAT signaling pathways, and regulated the cascade reaction of mitochondrial apoptosis signaling pathway. The results suggested that FTAs exerted anti-inflammatory effects by inhibiting NF-κB and JAK/STAT signaling pathways, promoted apoptosis by stimulating mitochondrial apoptosis signaling pathway, and inhibited cell proliferation by modulating cell cycle progression.

Advance in bone destruction participated by JAK/STAT in rheumatoid arthritis and therapeutic effect of JAK/STAT inhibitors

Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic joint inflammation and bone erosion. The bones in the human body are constantly undergoing bone remodeling throughout their lives, which is the process of bone resorption by osteoclasts to damaged bone tissue and new bone formation by osteoblasts. Osteoblasts (OBs) are the main functional cells in bone formation, responsible for the synthesis, secretion and mineralization of the bone matrix. On the contrary, osteoclasts (OCs) mediate bone breakdown during natural bone turnover, but excessive breakdown occurs in RA. Under the condition of RA inflammation, many molecules, such as IL-1β, IL-6, TNF-α, IL-17 and hypoxia-inducible factor-1α (HIF-1α) are produced that could mediate bone loss. Studies have shown that cytokines mainly promote the formation of OCs and play a role in bone resorption by stimulating OBs to express receptor activator of NF-κB ligand (RANKL). JAK/STAT plays a crucial role in the process of bone destruction. And JAK/STAT pathway mediates the RANKL/receptor activator of NF-κB (RANK)/osteoprotegerin (OPG) axis. Tofacitinib, Baricitinib, Peficitinib and Filgotinib are now being used in patients with moderate to severe RA, as well as in patients with RA who have an inadequate response to methotrexate therapy and bone destruction. Currently, Tofacitiniband Baritinib areapprovedfor thetreatmentof moderate-to-severely active RA. JAK inhibitors have been reported to have better efficacy and lower adverse effects compared with methotrexate and adalimumab. In addition, two JAK inhibitors are currently in development: the JAK1 selective Upadacitinib, and the JAK3 selective inhibitor Decernotinib. In addition to the above JAK inhibitors, some small molecular compounds inhibit bone destruction by inhibiting the Phosphorylation of STAT3. In this paper, the research progress of bone destruction participated by JAK/ STAT in rheumatoid arthritis and therapeutic effect of JAK/STAT inhibitors were reviewed.

Targeting of Janus Kinases Limits Pro-Inflammatory but Also Immunosuppressive Circuits in the Crosstalk between Synovial Fibroblasts and Lymphocytes

Crosstalk between synovial fibroblasts (SF) and immune cells plays a central role in the development of rheumatoid arthritis (RA). Janus kinase inhibitors (JAKi) have proven efficacy in the treatment of RA, although clinical responses are heterogeneous. Currently, little is known regarding how JAKi affect pro- and anti-inflammatory circuits in the bidirectional interplay between SF and immune cells. Here, we examined the effects of tofacitinib, baricitinib and upadacitinib on crosstalk between SF and T or B lymphocytes in vitro and compared them with those of biologic disease modifying anti-rheumatic drugs (bDMARDs). JAKi dose-dependently suppressed cytokine secretion of T helper (Th) cells and decreased interleukin (IL)-6 and matrix metalloproteinase (MMP)3 secretion of SF stimulated by Th cells. Importantly, JAK inhibition attenuated the enhanced memory response of chronically stimulated SF. Vice versa, JAKi reduced the indoleamine-2,3-dioxygenase (IDO)1-mediated suppression of T cell-proliferation by SF. Remarkably, certain bDMARDs were as efficient as JAKi in suppressing the IL-6 and MMP3 secretion of SF stimulated by Th (adalimumab, secukinumab) or B cells (canakinumab) and combining bDMARDs with JAKi had synergistic effects. In conclusion, JAKi limit pro-inflammatory circuits in the crosstalk between SF and lymphocytes; however, they also weaken the immunosuppressive functions of SF. Both effects were dose-dependent and may contribute to heterogeneity in clinical response to treatment.

The beneficial effect of baricitinib on ultrasound-detected synovial inflammation and bone damage in rheumatoid arthritis: Preliminarily data from single center-based observational study for 24 weeks

Baricitinib is a Janus kinase (JAK) inhibitor that selectively blocks against JAK1 and JAK2 signaling. This study aimed to determine the effect of baricitinib on disease activity based on musculoskeletal ultrasound in patients with rheumatoid arthritis (RA).A total of 20 patients with RA receiving baricitinib for 24 weeks were assessed. Ultrasound scores of gray scale and power Doppler synovitis, joint effusion, and bone erosion in each patient were assessed between baseline and 24 weeks for 27 affected joints. Disease activity in RA was evaluated using the disease activity score for 28-joint count with erythrocyte sediment rate (DAS28-ESR), simplified disease activity index (SDAI), and clinical disease activity index (CDAI).Treatment with baricitinib for 12 weeks and 24 weeks significantly decreased disease activity composites such as DAS28-ESR, SDAI, and CDAI (P < .001 for all). Treatment with baricitinib for 24 weeks improved ultrasound-detected gray-scale and power Doppler synovitis and joint effusion compared to baseline (P = .002, P = .030, and P = .002, respectively). Bone erosion scores were not different between baseline and 24 weeks (P = .317). There were no differences in ultrasound abnormalities for improvement based on DAS28-ESR. Changes in power Doppler score were significantly associated with changes in DAS28-ESR (β = 0.590, P = .044), but not SDAI and CDAI.This study demonstrates that baricitinib treatment has a favorable effect on ultrasound-detected abnormalities including synovitis and bone erosion in patients with RA.

JAK1: Number one in the family; number one in inflammation?

Several cytokines involved in inflammatory pathologies signal via the Janus kinase-signal transducer and activator of transcription pathway. Four JAKs are known: JAK1, JAK2, JAK3 and TYK2. The specific activation of JAKs and STATs determines the biological effects of each cytokine. JAK1 is involved in the signalling of 'γc' receptor cytokines (IL-2, IL-4, IL-7, IL-9, IL-15 and IL-21), pro-inflammatory cytokines including IL-6, as well as IFN. The critical position of JAK1 downstream of these cytokines suggests that JAK1-selective inhibitors are comparable to non-selective ones, without the unwanted consequences of JAK2- or JAK3-blockade. JAK inhibition has led to a better understanding of the biology of synovial inflammation and bone homeostasis. Moreover, the efficacy of non-selective JAK inhibitors and novel JAK1-selective drugs in RA supports a role for JAK1 in its pathogenesis. JAK1-selective drugs are also showing promise in axial spondyloarthritis, suggesting that they may target additional regulatory pathways that impact cytokines such as TNF and IL-17A, which do not use JAKs. Additionally, evidence now supports a JAK1 predominance in the signalling of IL-6 and oncostatin M, and indirectly, of TNF in synovial fibroblasts, macrophages and endothelial cells. Notably, bone homeostasis is also dependent on cytokines relying on JAK1 signalling to promote receptor activator of NF-κB ligand expression in osteoblasts and T cells, contributing to osteoclastogenesis. Here, the contribution of JAK1 over other kinases is unclear. While beneficial effects of JAK inhibitors on bone erosion are supported by preclinical and clinical data, effects on new bone formation in axial spondyloarthritis requires additional study.

Clinical pharmacology of filgotinib in the treatment of rheumatoid arthritis: current insights

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic autoimmune disease, whose natural course has been deeply modified thanks to the development of new therapeutic approaches. The Janus kinase inhibitors (Jakinibs) represent the newest class of drugs introduced for treating RA. Among these, Filgotinib (FIL) has been developed as Janus kinase1 (JAK1) selective inhibitor, specifically targeting key pro-inflammatory mediators in RA pathogenesis.

AREAS COVERED

This narrative review provides an overview on FIL as new therapeutic approach for RA, with focus on its pharmacological properties, clinical efficacy, and safety profile. The following electronic databases were adopted for the study search: PubMed, Google Scholar, ClinicalTrials.gov and Abstract archive from the American College of Rheumatology and the European Alliance of Associations for Rheumatology.

EXPERT OPINION

The phase II and phase III randomized controlled trials (RCTs) performed so far and their long-term extensions showed a comparable clinical efficacy of FIL to biologic treatments, with an acceptable safety profile. Thanks to these data, FIL was approved in Europe and Japan for the treatment of active RA, increasing the spectrum of therapeutic approaches and improving the possibility of a more tailored therapeutic strategy. Real-life data and head-to-head clinical trials will be needed to confirm its efficacy and safety.

The molecular structure and role of CCL2 (MCP-1) and C-C chemokine receptor CCR2 in skeletal biology and diseases

Monocyte chemoattractant protein-1, also called chemokine (C-C motif) ligand 2 (CCL2) or small inducible cytokine A2, is an inflammatory mediator capable of recruiting monocytes, memory T cells, and dendritic cells. CCL2 is a member of the CC chemokine superfamily, which binds to its receptor, C-C motif chemokine receptor-2 (CCR2), for the induction of chemotactic activity and an increase of calcium influx. It exerts multiple effects on a variety of cells, including monocytes, macrophages, osteoclasts, basophils, and endothelial cells, and is involved in a diverse range of diseases. This review discusses the molecular structure and role of CCL2 and CCR2 in skeletal biology and disease. Molecular structure analyses reveal that CCL2 shares a conserved C-C motif; however, it has only limited sequence homology with other CCL family members. Likewise, CCR2, as a member of the G-protein-coupled seven-transmembrane receptor superfamily, shares conserved cysteine residues, but exhibits very limited sequence homology with other CCR family members. In the skeletal system, the expression of CCL2 is regulated by a variety of factors, such as parathyroid hormone/parathyroid hormone-related peptide, interleukin 1b, tumor necrosis factor-α and transforming growth factor-beta, RANKL, and mechanical forces. The interaction of CCL2 and CCR2 activates several signaling cascades, including PI3K/Akt/ERK/NF-κB, PI3K/MAPKs, and JAK/STAT-1/STAT-3. Understanding the role of CCL2 and CCR2 will facilitate the development of novel therapies for skeletal disorders, including rheumatoid arthritis, osteolysis and other inflammatory diseases related to abnormal chemotaxis.

Drug repurposing and cytokine management in response to COVID-19: A review

Coronavirus disease 2019 (COVID-19), the infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is an aggressive disease that attacks the respiratory tract and has a higher fatality rate than seasonal influenza. The COVID-19 pandemic is a global health crisis, and no specific therapy or drug has been formally recommended for use against SARS-CoV-2 infection. In this context, it is a rational strategy to investigate the repurposing of existing drugs to use in the treatment of COVID-19 patients. In the meantime, the medical community is trialing several therapies that target various antiviral and immunomodulating mechanisms to use against the infection. There is no doubt that antiviral and supportive treatments are important in the treatment of COVID-19 patients, but anti-inflammatory therapy also plays a pivotal role in the management COVID-19 patients due to its ability to prevent further injury and organ damage or failure. In this review, we identified drugs that could modulate cytokines levels and play a part in the management of COVID-19. Several drugs that possess an anti-inflammatory profile in others illnesses have been studied in respect of their potential utility in the treatment of the hyperinflammation induced by SAR-COV-2 infection. We highlight a number of antivirals, anti-rheumatic, anti-inflammatory, antineoplastic and antiparasitic drugs that have been found to mitigate cytokine production and consequently attenuate the "cytokine storm" induced by SARS-CoV-2. Reduced hyperinflammation can attenuate multiple organ failure, and even reduce the mortality associated with severe COVID-19. In this context, despite their current unproven clinical efficacy in relation to the current pandemic, the repurposing of drugs with anti-inflammatory activity to use in the treatment of COVID-19 has become a topic of great interest.

tRNA-derived fragments (tRFs) regulate post-transcriptional gene expression via AGO-dependent mechanism in IL-1β stimulated chondrocytes

OBJECTIVES

Recent studies have shown that tRNA-derived RNA fragments (tRFs) are novel regulators of post-transcriptional gene expression. However, the expression profiles and their role in post-transcriptional gene regulation in chondrocytes is unknown. Here, we determined tRFs expression profile and explored tRF-3003a role in post-transcriptional gene regulation in IL-1β stimulated chondrocytes.

METHODS

We used qPCR arrays to determine tRNAs and tRFs expression in age- and sex-matched primary human OA chondrocytes and TC28/I2 cells stimulated with IL-1β. Chondrocytes were transfected with tRNA-Cys^GCA overexpression plasmid or tRF-3003a mimic and 3'UTR luciferase reporter plasmids of mRNAs harboring predicted tRF target "seed sequence". The AGO-RNA-induced silencing complex (AGO-RISC)-dependent repressive activity of tRF-3003a was determined by siRNA-mediated knockdown of AGO2.

RESULTS

IL-1β increased the expression levels of specific tRNAs and of tRF-3003a, a type 3 tRF produced by the cleavage of tRNA-Cys^GCA. tRF-3003a "seed sequence" was identified in the 3'UTR of JAK3 mRNA and tRNA-Cys^GCA overexpression or transfection of a tRF-3003a mimic in chondrocytes downregulated JAK3 expression and significantly reduced the activity of the 3'UTR reporter. RIP assay showed enrichment of tRF-3003a into AGO2/RISC in IL-1β treated chondrocytes. The suppressive effect of tRF-3003a on JAK3 3'UTR reporter was abrogated with siRNA-mediated depletion of AGO2.

CONCLUSIONS

We demonstrate that under pathological conditions chondrocytes display perturbations in the expression profile of specific tRNAs and tRFs. Furthermore, a specific tRF namely tRF-3003a can post-transcriptionally regulate JAK3 expression via AGO/RISC formation in chondrocytes. Identification of this novel mechanism may be of value in the design of precision therapies for OA.

CCDC7 Activates Interleukin-6 and Vascular Endothelial Growth Factor to Promote Proliferation via the JAK-STAT3 Pathway in Cervical Cancer Cells

Objective

Tumor growth is one of the most lethal attributes of human malignancy. The expression of CCDC7, a novel gene which has multiple functions, has been shown to be associated with tumor growth and poor prognosis in patients with cancer. However, the specific functions of CCDC7 remain unclear. Here, we investigated the molecular mechanisms underlying the effects of CCDC7 on proliferation in cervical cancer.

Materials and Methods

The MTT and EdU assays were performed to evaluate the function of CCDC7. The immunohistochemical, quantitative real-time PCR (qRT-PCR), ELISA and Western blot assay were used to detect the gene and protein expression in tissues and cells. A xenograft test was conducted to detect the impact of CCDC7 on tumor development in vivo .

Results

In immunohistochemical analysis of 193 cases, normal cervical tissue and cervical cancer tissue show that CCDC7 expression is closely correlated with the development of cervical cancer and was positively correlated with the clinical stage and histological grade. Overexpression or knockdown of CCDC7 affected cell proliferation in cervical cancer cells in vitro. In a nude mouse xenograft model in vivo, knockdown of CCDC7 inhibited cell proliferation and tumor growth. Furthermore, CCDC7 overexpression upregulated interleukin (IL)-6 and vascular endothelial growth factor (VEGF) at mRNA and protein levels, and treatment with recombinant IL-6 or VEGF proteins also increased CCDC7 expression. In a case set of 80 patients with cervical cancer, we found that CCDC7, IL-6, and VEGF affected patient prognosis. Finally, inhibition of various signaling pathways using specific inhibitors indicated that CCDC7 blocked the decrease in cell proliferation observed following suppression of the JAK-STAT3 pathway, suggesting that CCDC7 functioned via this critical signaling network.

Conclusion

Those findings indicated that CCDC7 may be a novel target for the treatment of cervical cancer and may have applications as a predictive marker for tumor growth in cervical carcinoma.

JAK-STAT inhibitors: Immersing therapeutic approach for management of rheumatoid arthritis

Rheumatoid arthritis is a world leading cause of musculoskeletal disease. With the introduction of biological agents as treatment alternatives the clinical possibilities have grown exponentially. Currently most common Disease-modifying anti-rheumatic drugs (DMARDs) treatment option involves intravenous or subcutaneous injection, and some patients struggle to respond to DMARDs or lose their primary reaction. An oral drug formulation with lowered costs of manufacturing and flexibility for healthcare workers to preferably perform treatment will result in decreased healthcare expenditures and increased medication compliance. The JAK-STAT inhibitors, a new class of small molecules drugs, fulfills these criteria and has recently shown efficacy in rheumatoid arthritis. Here we give a summary of how JAK-STAT inhibitors function and a detailed review of current clinical trials. Convincing clinical results suggest that therapeutic inhibition of the JAK proteins can effectively modulate a complex cytokine-driven inflammation.

Hi-JAKi-ng Synovial Fibroblasts in Inflammatory Arthritis With JAK Inhibitors

The Janus kinase (JAK)-Signal transducer and activator of transcription (STAT) pathway is one of the central signaling hubs in inflammatory, immune and cancer cells. Inhibiting the JAK-STAT pathway with JAK inhibitors (jakinibs) constitutes an important therapeutic strategy in cancer and chronic inflammatory diseases like rheumatoid arthritis (RA). FDA has approved different jakinibs for the treatment of RA, including tofacitinib, baricitinib and upadacitinib, and several jakinibs are being tested in clinical trials. Here, we reviewed published studies of jakinib effects on resolving synovial pathology in inflammatory arthritis. We discussed the results of jakinibs on structural joint damage in clinical trials and explored the effects of jakinibs across different in vitro, ex vivo, and in vivo synovial experimental models. We delved rigorously into experimental designs of in vitro fibroblast studies, deconvoluted jakinib efficacy in synovial fibroblasts across diverse experimental conditions and discussed their translatability in vivo. Synovial fibroblasts can readily activate the JAK-STAT signaling pathway in response to cytokine stimulation. We highlighted rather limited effects of jakinibs on the in vitro cultured synovial fibroblasts and inferred that direct and indirect (immune cell-dependent) actions of jakinibs are required to curb the fibroblast pathology in vivo. These actions have not been mimicked optimally in current in vitro experimental designs, where inflammatory stimuli do not naturally clear out with treatment as they do in vivo. While summarizing the broad knowledge of synovial jakinib effects, our review uniquely challenges future study designs to better mimick the jakinib actions in broader cell communities, as occurring in vivo in the inflamed synovium. This can deepen our understanding of collective synovial activities of jakinibs and their therapeutic limitations, thereby fostering jakinib development in arthritis.

Deriving a Boolean dynamics to reveal macrophage activation with in vitro temporal cytokine expression profiles

BACKGROUND

Macrophages show versatile functions in innate immunity, infectious diseases, and progression of cancers and cardiovascular diseases. These versatile functions of macrophages are conducted by different macrophage phenotypes classified as classically activated macrophages and alternatively activated macrophages due to different stimuli in the complex in vivo cytokine environment. Dissecting the regulation of macrophage activations will have a significant impact on disease progression and therapeutic strategy. Mathematical modeling of macrophage activation can improve the understanding of this biological process through quantitative analysis and provide guidance to facilitate future experimental design. However, few results have been reported for a complete model of macrophage activation patterns.

RESULTS

We globally searched and reviewed literature for macrophage activation from PubMed databases and screened the published experimental results. Temporal in vitro macrophage cytokine expression profiles from published results were selected to establish Boolean network models for macrophage activation patterns in response to three different stimuli. A combination of modeling methods including clustering, binarization, linear programming (LP), Boolean function determination, and semi-tensor product was applied to establish Boolean networks to quantify three macrophage activation patterns. The structure of the networks was confirmed based on protein-protein-interaction databases, pathway databases, and published experimental results. Computational predictions of the network evolution were compared against real experimental results to validate the effectiveness of the Boolean network models.

CONCLUSION

Three macrophage activation core evolution maps were established based on the Boolean networks using Matlab. Cytokine signatures of macrophage activation patterns were identified, providing a possible determination of macrophage activations using extracellular cytokine measurements.

Novel Therapeutic Approaches in Rheumatoid Arthritis: Role of Janus Kinases Inhibitors

:

Rheumatoid Arthritis (RA) is a chronic inflammatory disease characterized by synovial inflammation and hyperplasia, autoantibody production, cartilage and bone destruction and several systemic features. Cardiovascular, pulmonary, psychological, and muscle involvement are the main comorbidities of RA and are responsible for the severity of the disease and long-term prognosis.

:

Pharmacological treatment of rheumatic diseases has evolved remarkably over the past years. In addition, the widespread adoption of treat to target and tight control strategies has led to a substantial improvement of outcomes, so that drug-free remission is nowadays a realistic goal in the treatment of RA. However, despite the availability of multiple therapeutic options, up to 40% of patients do not respond to current treatments, including biologics. Small-molecule therapies offer an alternative to biological therapies for the treatment of inflammatory diseases. In the past 5 years, a number of small-molecule compounds targeting Janus Kinases (JAKs) have been developed. Since JAKs are essential for cell signaling in immune cells, in particular controlling the response to many cytokines, their inhibitors quickly became a promising class of oral therapeutics that proved effective in the treatment of RA.

:

ofacitinib is the first Janus Kinase (JAK) inhibitor approved for the treatment of RA, followed more recently by baricitinib. Several other JAK inhibitors, are currently being tested in phase II and III trials for the treatment of a different autoimmune diseases. Most of these compounds exhibit an overall acceptable safety profile similar to that of biologic agents, with infections being the most frequent adverse event. Apart from tofacitinib, safety data on other JAK inhibitors are still limited. Long-term follow-up and further research are needed to evaluate the general safety profile and the global risk of malignancy of these small molecules, although no clear association with malignancy has been reported to date.

:

Here, we will review the main characteristics of JAK inhibitors, including details on their molecular targets and on the clinical evidences obtained so far in the treatment of RA.

Current Therapeutic Options in the Treatment of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by chronic inflammation of the joints. Untreated RA leads to a destruction of joints through the erosion of cartilage and bone. The loss of physical function is the consequence. Early treatment is important to control disease activity and to prevent joint destruction. Nowadays, different classes of drugs with different modes of action are available to control the inflammation and to achieve remission. In this review, we want to discuss differences and similarities of these different drugs.

Targeting Activated Synovial Fibroblasts in Rheumatoid Arthritis by Peficitinib

Background: Synovial fibroblasts (SF) play a major role in the pathogenesis of rheumatoid arthritis (RA) and develop an aggressive phenotype destroying cartilage and bone, thus termed RASF. JAK inhibitors have shown to be an efficient therapeutic option in RA treatment, but less is known about the effect of JAK inhibitors on activated RASF. The aim of the study was to examine the effects of JAK inhibitors on activated RASF.

Methods: Synovium of RA patients was obtained during knee replacement surgeries. Synoviocytes were isolated and pretreated with JAK inhibitors. Pro-inflammatory cytokines and matrix degrading proteinases were measured by ELISA in supernatant after stimulation with oncostatin M or IL-1β. The proliferation of RASF was measured by BrdU incorporation. Cell culture inserts were used to evaluate cell migration. For adhesion assays, RASF were seeded in culture plates. Then, plates were extensively shaken and adherent RASF quantified. Cell viability, cytotoxicity and apoptosis were measured using the ApoTox-Glo™ Triplex and the CellTox™ Green Cytotoxicity Assay.

Results: Tofacitinib and baricitinib decreased the IL-6 release of RASF stimulated with oncostatin M. JAK inhibition attenuated the IL-6 release of IL-1β activated and with soluble IL-6 receptor treated RASF. In contrast, only peficitinib and filgotinib decreased the IL-6 release of RASF activated with IL-1β. Peficitinib decreased also the MMP-3, CXCL8, and CXCL1 release at 5 μM. Moreover, peficitinib was the only JAK inhibitor suppressing proliferation of activated RASF at 1 μM. Peficitinib further decreased the migration of RASF without being cytotoxic or pro-apoptotic and without altering cell adhesion.

Conclusions: JAK inhibitors effectively suppress the inflammatory response induced by oncostatin M and by transsignaling of IL-6 in RASF. Only peficitinib modulated the IL-1β-induced response of RASF and their proliferation in vitro at concentrations close to reported Cmax values of well tolerated doses in vivo. In contrast to filgotinib, peficitinib also highly suppressed RASF migration showing the potential of peficitinib to target RASF.

Clinical efficacy of launched JAK inhibitors in rheumatoid arthritis

Tofacitinib and baricitinib are the first orally available, small-molecule inhibitors of Janus kinase (JAK) enzymes to be approved for the treatment of RA. Tofacitinib is a selective JAK1, 3 inhibitor with less activity against JAK2 and TYK2 and baricitinib is a selective, oral JAK1, 2 inhibitor with moderate activity against TYK2 and significantly less activity against JAK3. Both drugs have undergone extensive phase III clinical trials in RA and demonstrated rapid improvements in disease activity, function and patient-reported outcomes as well as disease modification. Tofacitinib 5 mg bd, was approved by the Federal Drug Administration in 2012 for the treatment of RA in patients who are intolerant or unresponsive to MTX. An extended release formulation for the treatment of RA was approved by Federal Drug Administration in 2016. In 2017 the European Medicines Agency approved tofacitinib 5 mg bd in combination with MTX and baricitinib 4 mg and 2 mg once daily for the treatment of moderate to severe active RA in adult patients who are intolerant or unresponsive to one or more conventional synthetic DMARDs.

Curculigoside exerts significant anti‑arthritic effects in vivo and in vitro via regulation of the JAK/STAT/NF‑κB signaling pathway

The present study aimed to investigate the anti-arthritic effects of curculigoside isolated from the rhizome of Curculigo orchioides Gaertn in vivo and in vitro, as well as to determine the potential underlying mechanisms. A rat model of arthritis was induced with type II collagen. Arthritic rats were treated with curculigoside (50 mg/kg) and blood samples were collected to determine serum levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-10, IL-12 and IL-17A. Furthermore, indices of the thymus and spleen were determined. The anti-proliferative effects of curculigoside were detected with Cell Counting kit-8 assays in rheumatoid arthritis-derived fibroblast-like synoviocyte MH7A cells. In addition, expression levels of Janus kinase (JAK)1, JAK3, signal transducer and activator of transcription (STAT)3, nuclear factor (NF)-κB p65 and its inhibitor (IκB) were determined by western blotting. The results revealed that curculigoside inhibited paw swelling and arthritis scores in type II collagen-induced arthritic (CIA) rats. Additionally, curculigoside decreased serum levels of TNF-α, IL-1β, IL-6, IL-10, IL-12 and IL-17A in CIA rats. Curculigoside also significantly inhibited MH7A cell proliferation in a time and concentration-dependent manner. Furthermore, treatment downregulated the expression of JAK1, JAK3 and STAT3, and upregulated cytosolic nuclear factor (NF)-κB p65 and IκB. In conclusion, the results of the present study indicated that curculigoside exhibited significant anti-arthritic effects in vivo and in vitro, and the molecular mechanism may be associated with the JAK/STAT/NF-κB signaling pathway.

Cryptotanshinone induces reactive oxygen species‑mediated apoptosis in human rheumatoid arthritis fibroblast‑like synoviocytes

The present study investigated the mechanisms of apoptosis induced by cryptotanshinone (CT) in human rheumatoid arthritis fibroblast‑like synoviocytes (RA‑FLSs). Cell Counting kit‑8 assay was performed to determine the cytotoxic effects of CT in human RA‑FLSs, including primary RA‑FLS, HFLS‑RA and MH7A cells, and in HFLS cells derived from normal synovial tissue. Annexin V‑FITC/PI staining was used to detect the apoptotic effects of CT in HFLS‑RA and MH7A cells. Flow cytometry was performed to detect the apoptotic and reactive oxygen species (ROS) levels induced by CT in HFLS‑RA cells. Western blotting was used to assess the expression levels of proteins associated with apoptosis and with the mitogen‑activated protein kinase (MAPK), protein kinase B (Akt), and signal transducer and activator of transcription‑3 (STAT3) signaling pathways. The results demonstrated that CT treatment significantly suppressed HFLS‑RA and MH7A cell growth, whereas no clear inhibitory effect was observed in normal HFLS cells. CT exposure downregulated the expression levels of B‑cell lymphoma 2 (Bcl‑2), p‑Akt, p‑extracellular signal‑related kinase and p‑STAT3, while it upregulated the expression levels of Bcl‑2‑associated death promoter (Bad), caspase‑3, poly (ADP‑ribose) polymerase (PARP), p‑p38 and p‑c‑Jun N‑terminal kinase. Following ROS scavenging, the CT‑induced apoptosis and altered expression levels of Bcl‑2, Bad, cleaved caspase‑3 and cleaved PARP were restored. Furthermore, the Akt, MAPK and STAT3 signaling pathways were regulated by intracellular ROS. These results suggest that ROS‑mediated Akt, MAPK and STAT3 signaling pathways serve important roles in the CT‑induced apoptosis of RA‑FLSs.

Filgotinib for the treatment of rheumatoid arthritis

INTRODUCTION

Biologics were the first targeted therapies for rheumatoid arthritis (RA), having in common high clinical efficacy. Being proteins, they are administered parenterally. The first oral targeted small molecules approved for RA are competitive inhibitors of the Janus kinase (JAK) enzyme family which mediate signalling for a cytokine subset important in RA pathogenesis. Areas covered: Several JAK inhibitors have been developed with differing selectivity for the four JAK enzymes with a view to generating oral, multi-cytokine inhibitors. Here we review the pharmacology and clinical trial data for efficacy and safety of filgotinib, an investigational selective JAK1 inhibitor. We contextualise the contemporary approach to RA management and substantial unmet needs that remain. Expert opinion: The selectivity of filgotinib for JAK1 may have theoretical advantages in terms of limiting toxicity. However, establishing whether this is so before larger numbers of patients are exposed in phase III and beyond in the real word setting, will be difficult. Filgotinib clinical trial data to date has been encouraging with rapid, sustained efficacy with promising safety and tolerability. We are likely to see an expanding choice of approved JAK inhibitors in the clinic but it may not be straightforward to distinguish safety and efficacy differences.

The barrier hypothesis and Oncostatin M: Restoration of epithelial barrier function as a novel therapeutic strategy for the treatment of type 2 inflammatory disease

Mucosal epithelium maintains tissue homeostasis through many processes, including epithelial barrier function, which separates the environment from the tissue. The barrier hypothesis of type 2 inflammatory disease postulates that epithelial and epidermal barrier dysfunction, which cause inappropriate exposure to the environment, can result in allergic sensitization and development of type 2 inflammatory disease. The restoration of barrier dysfunction once it's lost, or the prevention of barrier dysfunction, have the potential to be exciting new therapeutic strategies for the treatment of type 2 inflammatory disease. Neutrophil-derived Oncostatin M has been shown to be a potent disrupter of epithelial barrier function through the induction of epithelial-mesenchymal transition (EMT). This review will discuss these events and outline several points along this axis at which therapeutic intervention could be beneficial for the treatment of type 2 inflammatory diseases.

Selective Downregulation of JAK2 and JAK3 by an ATP-Competitive pan-JAK Inhibitor

PF-956980 has been used previously as a JAK3-selective chemical probe in numerous cell-based experiments. Here, we report that not only is PF-956980 a pan-JAK ATP-competitive inhibitor but it also causes selective reduction of endogenous JAK2 and JAK3 protein levels in human primary immune cells (in a time-dependent manner), leaving the other JAK family members (JAK1 and TYK2) unchanged. We found that PF-956980 selectively downregulated JAK2 and JAK3 mRNA, corresponding to changes observed at the protein level. This work highlights therapeutic opportunities for the development of pharmacological inhibitors that also modulate the expression of their cognate binding proteins.

Baseline JAK phosphorylation profile of peripheral blood leukocytes, studied by whole blood phosphospecific flow cytometry, is associated with 1-year treatment response in early rheumatoid arthritis

Background

We found recently that baseline signal transducer and activator of transcription 3 phosphorylation in peripheral blood CD4⁺ T cells of patients with early rheumatoid arthritis (RA) is associated with treatment response to synthetic disease-modifying antirheumatic drugs (DMARDs). This prompted us to study the baseline phosphorylation profiles of Janus kinases (JAKs) in blood leukocytes with respect to treatment response in early RA.

Methods

Thirty-five DMARD-naïve patients with early RA provided blood samples for whole blood flow cytometric determination of phosphorylation of JAKs in CD4⁺ and CD8⁺ T cells, CD19⁺ B cells, and CD14⁺ monocytes. Treatment response was determined after 1 year of treatment with synthetic DMARDs, with remission defined as absence of tender and swollen joints and normal erythrocyte sedimentation rate. Exact logistic regression was used to investigate the association of baseline variables with treatment response. Ninety-five percent CIs of means were estimated by bias-corrected bootstrapping.

Results

High JAK3 phosphorylation in CD4⁺ and CD8⁺ T cells, CD19⁺ B cells, and CD14⁺ monocytes and low JAK2 phosphorylation in CD14⁺ monocytes were significantly associated with remission following treatment with synthetic DMARDs.

Conclusions

Baseline JAK phosphorylation profile in peripheral blood leukocytes may provide a means to predict treatment response achieved by synthetic DMARDs among patients with early RA.

STA-21, a STAT-3 inhibitor, attenuates the development and progression of inflammation in collagen antibody-induced arthritis

We set out to investigate the influence of STA-21, a dynamic STAT-3 inhibitor, on the expansion and progression of rheumatoid arthritis (RA), and to determine its potential mechanisms of action in a mouse model of collagen antibody-induced arthritis (CAIA). To this end, arthritis was induced via intravenous (IV) injection of Balb/c mice with a cocktail of antibodies directed against type II collagen (1.5μg/mouse, IV), followed by lipopolysaccharide (LPS) at a dose of (25μg/mouse, i.p.) on day 3. Mice were then left untreated or were simultaneously treated with STA-21 (0.5mg/kg, i.p., once daily for 2 weeks) followed by evaluation for clinical and histological features of arthritic inflammation and flow cytometric analysis of cytokines and transcription factors in peripheral blood. STA-21 enhanced the clinical course of arthritis in CAIA mice and decreased CD8⁺RORγt⁺ and CD8⁺IL-21⁺ cells while inducing the production of CD8⁺Foxp3⁺ cells. Furthermore, STA-21 prevented the production of TNF-α and IL-6 in peripheral blood and increased IL-27 production by CD14⁺ cells. Moreover, STA-21 not only regulates Th1/Th2 serum cytokine levels but also the mRNA and protein expression of key factors including NF-κB p65, RORγt, T-bet, IL-4, GATA-3, JAK1, Stat3, and IL-21. Thus, administration of the Stat3 inhibitor STA-21 inhibits cellular signaling pathways and downstream activation of key transcription factors previously shown to play key roles in the pathogenesis of RA. Therefore, these data suggest that STA-21 could be considered as a potential treatment for patients with RA.

New treatments for inflammatory rheumatic disease

As our understanding of the pathogenesis of autoimmune diseases is growing, new therapies are being developed to target disease-specific pathways. Since the introduction of etanercept in 1998, several biotechnological agents have been developed, most of them indicated in the treatment of rheumatoid arthritis, but also psoriatic arthritis. Most currently available molecules target TNF-alfa with different strategies (i.e., etanercept, infliximab, adalimumab, golimumab, and certolizumab pegol), IL-6 (tocilizumab), CTLA-4 (abatacept), and B cells (rituximab, belimumab) as they are key mediators in the cascade of inflammation. Further, small molecules have been recently developed to target intracellular signaling, such as Janus Kinases for tofacitinib, the first FDA-approved small molecule for rheumatoid arthritis. Most novel treatments are being developed for arthritis with specific differences between rheumatoid and psoriatic arthritis, as well as for systemic lupus erythematosus, following the approval of belimumab. Finally, biologic therapies are effective also in gout, mainly targeting interleukin-1 to block the inflammasome. This review article describes the new and upcoming treatment options for rheumatoid arthritis, psoriatic arthritis, systemic lupus erythematosus, and gout to dissect what we should be aware of when discussing these new and promising molecules.

Oncostatin M promotes mucosal epithelial barrier dysfunction, and its expression is increased in patients with eosinophilic mucosal disease

BACKGROUND

Epithelial barrier dysfunction is thought to play a role in many mucosal diseases, including asthma, chronic rhinosinusitis (CRS), and eosinophilic esophagitis.

OBJECTIVE

The objective of this study was to investigate the role of oncostatin M (OSM) in epithelial barrier dysfunction in human mucosal disease.

METHODS

OSM expression was measured in tissue extracts, nasal secretions, and bronchoalveolar lavage fluid. The effects of OSM stimulation on barrier function of normal human bronchial epithelial cells and nasal epithelial cells cultured at the air-liquid interface were assessed by using transepithelial electrical resistance and fluorescein isothiocyanate-dextran flux. Dual-color immunofluorescence was used to evaluate the integrity of tight junction structures in cultured epithelial cells.

RESULTS

Analysis of samples from patients with CRS showed that OSM mRNA and protein levels were highly increased in nasal polyps compared with those seen in control uncinate tissue (P < .05). OSM levels were also increased in bronchoalveolar lavage fluid of allergic asthmatic patients after segmental allergen challenge and in esophageal biopsy specimens from patients with eosinophilic esophagitis. OSM stimulation of air-liquid interface cultures resulted in reduced barrier function, as measured by decreased transepithelial electrical resistance and increased fluorescein isothiocyanate-dextran flux (P < .05). Alterations in barrier function by OSM were reversible, and the viability of epithelial cells was unaffected. OSM levels in lysates of nasal polyps and uncinate tissue positively correlated with levels of α2-macroglobulin, a marker of epithelial leak, in localized nasal secretions (r = 0.4855, P < .05).

CONCLUSIONS

These results suggest that OSM might play a role in epithelial barrier dysfunction in patients with CRS and other mucosal diseases.

Protein kinase small molecule inhibitors for rheumatoid arthritis: Medicinal chemistry/clinical perspectives

Medicinal chemistry strategies have contributed to the development, experimental study of and clinical trials assessment of the first type of protein kinase small molecule inhibitor to target the Janus kinase/Signal Transducers and Activators of Transcription (JAK/STAT) signaling pathway. The orally administered small molecule inhibitor, tofacitinib, is the first drug to target the JAK/STAT pathway for entry into the armamentarium of the medical therapy of rheumatoid arthritis. The introduction of tofacitinib into general rheumatologic practice coupled with increasing understanding that additional cellular signal transduction pathways including the mitogen-activated protein kinase and phosphatidylinositide-3-kinase/Akt/mammalian target of rapamycin pathways as well as spleen tyrosine kinase also contribute to immune-mediated inflammatory in rheumatoid arthritis makes it likely that further development of orally administered protein kinase small molecule inhibitors for rheumatoid arthritis will occur in the near future.

Emerging immunotherapies for rheumatoid arthritis

Novel treatments in development for rheumatoid arthritis target 3 broad areas: cytokines, cells, and signaling pathways. Therapies from each domain share common advantages (for example previously demonstrated efficacy, potential long-term immunomodulation, and oral administration respectively) that have stimulated research in each area but also common obstacles to their development. In this review recent progress in each area will be discussed alongside the factors that have impeded their path to clinical use.