As it is nonvascularized and noninnervated, articular cartilage has a limited capacity to repair which presents a major clinical problem. In order to circumvent this inability to repair, stem cells can be placed into the joint or stimulated within the bone marrow. However, as the cartilage requiring repair is often in diseased joints, the factors involved in the disease state are potentially non-beneficial to the chondrogenesis of mesenchymal stem cells. In this study van Beuningen et al. invest...

February 2014

Despite biologic therapies greatly improving the treatment of rheumatoid arthritis, many patients do not respond to current treatments or do not maintain response to these treatments. This review covers the evidence for the newly discovered role of Th17 cells, IL-12 and IL-17 family of cytokines in the pathogenesis of RA as well as the development of new therapies targeting these cytokines. With current biologics targeting cytokines such as TNF, IL-1ß and IL-6, the discovery of the Th17 subset o...

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January 2014

Spleen tyrosine kinase (SYK) has already been described as a potential therapeutic target for the treatment of autoimmune diseases. Previously the SYK inhibitor fostamatinib was in clinical development for the treatment of rheumatoid arthritis, but has since been suspended. However, investigation into SYK inhibition continues with RO2091, a novel ATP-competitive inhibitor of SYK with reasonable selectivity, potency and oral bioavailability which has been shown to suppress various innate and adap...

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A large number of loci implicated in disease susceptibility have been identified through genome-wide association studies (GWAS). In this review article, Diogo et al. discuss recent advances in GWAS in the context of rheumatoid arthritis pathogenesis and clinical applications. Relevant cells types and pathways in RA highlighted by GWAS to date include regulatory T-cells and CD4+ memory T cells as well as the JAK/STAT and NF-kB signalling pathways. The development of drugs targeting these pathways...

November 2013

Therapeutic Targeting of the JAK/STAT Pathway

Basic Clin Pharmacol Toxicol. 2013 Oct 24. doi: 10.1111/bcpt.12164

The inhibition of the JAK/STAT pathway has proven to be a powerful therapeutic tool in the treatment of autoimmune diseases. The authors review the role of the JAK/STAT pathway in human disease, including the role of mutations in defective function of this pathway. They discuss the rationale behind JAK inhibition and review the two JAK inhibitors currently approved by the FDA for clinical use; tofacitinib, for the treatment of RA, and ruxolitinib, for the treatment of polycythaemia vera and myel...

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October 2013

The JAK/STAT signalling pathway has been implicated in the pathogenesis of several inflammatory diseases including inflammatory bowel disease (IBD) and rheumatoid arthritis (RA). In this review, Coskun et al. provide an excellent background overview of the JAK/STAT cascade. They also highlight recent study findings investigating the mechanisms of the JAK/STAT pathway and the anti-inflammatory effects of novel JAK inhibitors in development and in clinical trials, particularly in IBD. In one study...

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The role of JAKs is highly important in lymphocyte differentiation, but their function in dendritic cells in unknown. In this study, the authors used tofacitinib, a JAK inhibitor, to assess the function of these kinases in dendritic cell activity. The results show that tofacitinib reduced the expression of CD80/CD86 by suppressing the activation of interferon regulatory factor (IRF)-7 and production of type 1 interferon (IFN), and also decreased T cell stimulatory capability. This suggests a nov...

August 2013

The JAK inhibitor tofacitinib for active rheumatoid arthritis: results from phase III trials

International Journal of Clinical Rheumatology June 2013; 8(3):311–13

The tofacitinib ORAL research program involves six phase 3 trials (Standard, Solo, Step, Scan, Sync and Start) to assess the safety and efficacy of tofacitinib 5 and 10 mg twice daily as monotherapy, or with either background MTX or traditional DMARD therapy. This report by Salgado et al. provides an overall analysis of the each of the study designs and the clinical results to date. The results show that tofacitinib effectively controlled the signs and symptoms of RA across a range of patient po...

June 2013

This review from 2007 provides an overview of the largest cytokine receptor family, the haematopoietin receptors, as well as other key components involved in one of the major cytokine signalling pathways implicated in autoimmune and inflammatory diseases. This includes the Janus kinases (Jaks), signal transducers and activators of transcription (Stats) and suppressors of cytokine signalling genes (Socs). Essentially, when a cytokine binds to a receptor from this group a functional cytokine recep...

Janus kinases in immune cell signaling

Immunological Reviews 2009; 228:273-87

This review from 2009 describes the Janus Kinases (JAK) that includes JAK1, JAK2, and JAK3, a subgroup of non-receptor protein tyrosine kinases. This protein family has a diverse range of functions including roles in cell growth, survival, development, and differentiation of a variety of cells, and especially immune and haematopoietic cells. Current knowledge of protein structure, regulatory mechanisms, signalling pathways and intracellular interactions for the JAK family is reviewed. The paper ...

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