June 2015

TNF-α and IL-6 differentially regulate Dkk-1 in the inflamed arthritic joint

Arthritis Rheumatol. 2015 May 4. doi: 10.1002/art.39183. [Epub ahead of print]

Different inflammatory joint diseases have distinct patterns of bone damage, but the molecular pathways determining each one remains poorly defined. This study investigates the wingless (Wnt)-signalling pathway, by analysing the expression of Dkk-1 (an inhibitor of the Wnt pathway) and its regulation by the pro-inflammatory cytokines TNF-α and IL-6 in SpA versus RA inflamed peripheral joints.Findings from the study show an inverse correlation of Dkk-1 with IL-6 in vivo and a differential regulat...

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May 2015

Differential Effects of IL-17A and TNF-α on Osteoblastic Differentiation of Isolated Synoviocytes and on Bone Explants from Arthritis Patients

Frontiers in Immunology. 2015;6:151. doi:10.3389/fimmu.2015.00151

Inflammatory joint diseases such as RA and OA are characterised by bone and consequent joint destruction. The role of fibroblast-like synoviocytes (FLS) in the pathogenesis of such diseases is already established. This study compared the effects of TNF-α and IL-17A on osteogenic differentiation of isolated FLS and on whole bone explants from 3 RA and 10 OA patients.Results showed that isolated RA-FLS appeared more sensitive to the effects of TNF-α and IL-17A compared to OA-FLS. These findings su...

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Tofacitinib, an oral Janus kinase inhibitor: analysis of malignancies across the rheumatoid arthritis clinical development programme

Ann Rheum Dis. 2015 Apr 22. pii: annrheumdis-2014-205847. doi: 10.1136/annrheumdis-2014-205847. [Epub ahead of print]

The developments of certain malignancies associated with chronic inflammatory diseases such as RA is known to occur to a greater extent than that of the general population. It is also know that certain RA treatments can affect malignancy rates. As such, newer immunomodulatory agents, such as the JAK inhibitor tofacitinib, are closely monitored for safety events of special interest, including malignancies.

This paper analyses pooled malignancy data from the tofacitinib RA clinical develop...

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March 2015

A small-molecule inhibitor of the NLRP3 inflammasome for the treatment of inflammatory diseases

Nat Med. 2015 Feb 16. doi: 10.1038/nm.3806. [Epub ahead of print]

A team of scientists at Trinity College Dublin and the University of Queensland Australia, led by Professor Luke O'Neill, have identified a key molecule that may result in the development of new anti-inflammatory therapies for diseases such as: cryopyrin-associated periodic syndrome (CAPS), multiple sclerosis, type 2 diabetes, Alzheimer’s disease and atherosclerosis.

Professor O'Neill and his team have identified MCC950 as a potent, selective, small-molecule inhibitor of the NLRP3 infla...

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January 2015

Potential Mechanisms Leading to the Abnormal Lipid Profile in Patients With Rheumatoid Arthritis Versus Healthy Volunteers and Reversal by Tofacitinib

Arthritis Rheumatol. 2015;67(3):616-25.

Active RA is associated with changes in both high- and low-density lipoprotein cholesterol as well as changes in the level and function of several HDL-associated proteins, yet the pathways and mechanisms involved with systemic inflammation altered lipid metabolism have not been determined. In addition, treatments for active RA are known to modify lipid metabolism, such as increasing circulating cholesterol levels. In the clinical development programme, a proportion of tofacitinib-treated patien...

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The pharmacokinetics, pharmacodynamics, and safety of baricitinib, an oral JAK 1/2 inhibitor, in healthy volunteers

Mod J Clin Pharmacol. 2014 Dec;54(12):1354-61. doi: 10.1002/jcph.354.

Current biologic therapies for RA, such as biologic cytokine inhibitors, which selectively target inflammatory molecules with an exquisite degree of specificity, are not clinically effective in all patients with rheumatoid arthritis. As such, there remains an unmet clinical need for more effective and better tolerated therapies. Baricitinib (LY3009104, also previously known as INCB028050) is a potent and selective small molecule inhibitor of JAK1/2, which play an important role in cytokine signa...

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IL-6 stimulates intestinal epithelial proliferation and repair after injury

PLoS One. 2014 Dec 5;9(12):e114195. doi: 10.1371/journal.pone.0114195. eCollection 2014.

IL-6 is an inflammatory cytokine known to contribute to a number of autoimmune diseases such as RA. Therapies targeting the soluble IL-6 receptor have now become effective treatments for RA. However, one unforeseen, yet rare, potential complication of anti-IL-6 therapy is bowel perforation. Yet within the intestine, IL-6 protects intestinal epithelial cells from apoptosis during prolonged inflammation.

The authors hypothesized that IL-6 may have beneficial properties in wound response/rep...

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December 2014

The activity of JAK-STAT pathways in rheumatoid arthritis: constitutive activation of STAT3 correlates with interleukin 6 levels

Rheumatology (Oxford). 2014 Nov 17. pii: keu430. [Epub ahead of print]

Non-response, parenteral administration and cost to produce are all aspects associated with the currently available anti-cytokine agents for RA. These related factors mean that alternative drugs are now being developed. Recent developments in therapeutic drugs to treat RA have focused on Janus kinases (JAKs) and signal transducer and activator of transcription (STATs) transcription pathways. Several cytokines that regulate immune responses in RA, such as IFN-g, IL-6 and IL-10, activate JAK-STAT ...

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The JAK inhibitor tofacitinib suppresses synovial JAK1-STAT signalling in rheumatoid arthritis

Ann Rheum Dis. 2014 Nov 14. pii: annrheumdis-2014-206028. doi: 10.1136/annrheumdis-2014-206028. [Epub ahead of print]

Targeting intracellular pathways such as JAK/STAT represents a novel approach to the treatment of RA. Tofacitinib is an oral JAK inhibitor, proven to be effective in the treatment of RA, yet the pathways affected by tofacitinib and the effects on gene expression in situ are unknown. In this study, Boyle et al. tested the hypothesis that tofacitinib targets cytokine signalling critical to the pathogenesis of rheumatoid synovitis by investigating tofacitinib effects on synovial pathobiology.

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September 2014

The active metabolite of spleen tyrosine kinase inhibitor fostamatinib abrogates the CD4+T cell-priming capacity of dendritic cells

Rheumatology (Oxford). 2015;54(1):169–177

SYK is a core signalling protein that drives inflammatory responses and is fundamental to the propagation of signals via numerous immune receptors. While the clinical development of the first SYK inhibitor, fostamatinib, was stopped due to poor results in the phase 3 RA programme, there remain important questions of mechanism which may aid future developments of this target.

In these murine studies, investigators sought to gain an understanding of how the active metabolite of fostamatini...

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