n4-(2-2-dimethyl-3-oxo-4h-pyrid(1-4)oxazin-6-yl)-5-fluoro-n2-(3-4-5-trimethoxyphenyl)-2-4-pyrimidinediamine and tofacitinib

Currently, there are no disease-modifying osteoarthritis drugs (DMOADs) approved for osteoarthritis. It is hypothesized that a subtype of OA may be driven by inflammation and may benefit from treatment with anti-inflammatory small molecule inhibitors adopted from treatments of rheumatoid arthritis. This study aimed to investigate how small molecule inhibitors of intracellular signaling modulate cartilage degradation and formation as a pre-clinical model for structural effects.. Bovine cartilage explants were cultured with oncostatin M (OSM) and tumour necrosis factor α (TNF-α) either alone or combined with the small molecule inhibitors: SB203580 (p38 inhibitor), R406 (Spleen tyrosine kinase (Syk) inhibitor), TPCA-1 (Inhibitor of κB kinase (Ikk) inhibitor), or Tofacitinib (Tofa) (Janus kinases (Jak) inhibitor). Cartilage turnover was assessed with the biomarkers of degradation (AGNx1 and C2M), and type II collagen formation (PRO-C2) using ELISA. Explant proteoglycan content was assessed by Safranin O/Fast Green staining.. R406, TPCA-1 and Tofa reduced the cytokine-induced proteoglycan loss and decreased AGNx1 release 3.7-, 43- and 32-fold, respectively. SB203580 showed no effect. All inhibitors suppressed C2M at a concentration of 3 µM. TPCA-1 and Tofa increased the cytokine reduced PRO-C2 3.5 and 3.7-fold, respectively.. Using a pre-clinical model we found that the inhibitors TPCA-1 and Tofa inhibited cartilage degradation and rescue formation of type II collagen under inflammatory conditions, while R406 and SB203580 only inhibited cartilage degradation, and SB203580 only partially. These pre-clinical data suggest that TPCA-1 and Tofa preserve and help maintain cartilage ECM under inflammatory conditions and could be investigated further as DMOADs for inflammation-driven osteoarthritis.

Topics: Amides; Animals; Cartilage, Articular; Cattle; Chondrocytes; Collagen Type II; Extracellular Matrix Proteins; Imidazoles; Osteoarthritis; Oxazines; Piperidines; Proteoglycans; Pyridines; Pyrimidines; Pyrroles; Thiophenes

The rising incidence of obesity and related disorders such as diabetes and heart disease has focused considerable attention on the discovery of new therapeutics. One promising approach has been to increase the number or activity of brown-like adipocytes in white adipose depots, as this has been shown to prevent diet-induced obesity and reduce the incidence and severity of type 2 diabetes. Thus, the conversion of fat-storing cells into metabolically active thermogenic cells has become an appealing therapeutic strategy to combat obesity. Here, we report a screening platform for the identification of small molecules capable of promoting a white-to-brown metabolic conversion in human adipocytes. We identified two inhibitors of Janus kinase (JAK) activity with no precedent in adipose tissue biology that stably confer brown-like metabolic activity to white adipocytes. Importantly, these metabolically converted adipocytes exhibit elevated UCP1 expression and increased mitochondrial activity. We further found that repression of interferon signalling and activation of hedgehog signalling in JAK-inactivated adipocytes contributes to the metabolic conversion observed in these cells. Our findings highlight a previously unknown role for the JAK-STAT pathway in the control of adipocyte function and establish a platform to identify compounds for the treatment of obesity.

Topics: Adipocytes, Brown; Adipocytes, White; Animals; Bone Morphogenetic Protein 7; Cell Differentiation; Cells, Cultured; Gene Expression Profiling; Hedgehog Proteins; Humans; Interferon-gamma; Ion Channels; Janus Kinase 1; Janus Kinase 3; Male; Mice; Mice, Inbred C57BL; Mitochondria; Mitochondrial Proteins; Obesity; Oxazines; Phosphorylation; Piperidines; Protein Kinase Inhibitors; Pyridines; Pyrimidines; Pyrroles; STAT1 Transcription Factor; STAT3 Transcription Factor; Tumor Necrosis Factor-alpha; Uncoupling Protein 1; Veratrum Alkaloids

To investigate whether a narrow spectrum kinase inhibitor RV1088, which simultaneously targets specific MAPKs, Src and spleen tyrosine kinase (Syk), is more effective at inhibiting inflammatory signalling in rheumatoid arthritis (RA) than single kinase inhibitors (SKIs).. elisas were used to determine the efficacy of RV1088, clinically relevant SKIs and the pharmaceutical Humira on pro-inflammatory cytokine production by activated RA synovial fibroblasts, primary human monocytes and macrophages, as well as spontaneous cytokine synthesis by synovial membrane cells from RA patients. In human macrophages, RNAi knockdown of individual kinases was used to reveal the effect of inhibition of kinase expression on cytokine synthesis.. RV1088 reduced TNF-α, IL-6 and IL-8 production in all individual activated cell types with low, nM, IC50 s. SKIs, and combinations of SKIs, were significantly less effective than RV1088. RNAi of specific kinases in macrophages also caused only modest inhibition of pro-inflammatory cytokine production. RV1088 was also significantly more effective at inhibiting IL-6 and IL-8 production by monocytes and RA synovial fibroblasts compared with Humira. Finally, RV1088 was the only inhibitor that was effective in reducing TNF-α, IL-6 and IL-8 synthesis in RA synovial membrane cells with low nM IC50 s.. This study demonstrates potent anti-inflammatory effect of RV1088, highlighting that distinct signalling pathways drive TNF-α, IL-6 and IL-8 production in the different cell types found in RA joints. As such, targeting numerous signalling pathways simultaneously using RV1088 could offer a more powerful method of reducing inflammation in RA than targeting individual kinases.

Topics: Acetamides; Adalimumab; Anti-Inflammatory Agents; Arthritis, Rheumatoid; Dasatinib; Dose-Response Relationship, Drug; Humans; Inflammation Mediators; Interleukin-6; Interleukin-8; Macrophages; Monocytes; Naphthalenes; Oxazines; Piperidines; Primary Cell Culture; Protein Kinase Inhibitors; Pyrazoles; Pyridines; Pyrimidines; Pyrroles; RNA, Small Interfering; Signal Transduction; Synovial Membrane; Tumor Necrosis Factor-alpha; Urea