TAS05567, a Novel Potent and Selective Spleen Tyrosine Kinase Inhibitor, Abrogates Immunoglobulin-Mediated Autoimmune and Allergic Reactions in Rodent Models

Abstract

Spleen tyrosine kinase (Syk) is involved in regulation of B-cell receptor (BCR) and Fc receptor downstream signal pathways. Syk plays an essential role in production of inflammatory mediators and differentiation in various immune cells and is therefore an attractive target for treating inflammatory conditions, such as autoimmune and allergic diseases. We identified TAS05567 as a highly selective Syk inhibitor and evaluated its therapeutic potential in animal models. In vitro biochemical assays were performed with available kinase assay panels. Inhibitory effects of TAS05567 on immune cells were analyzed by assessing the Syk downstream signaling pathway and production of inflammatory factors. In vivo effects of TAS05567 were evaluated in animal models of autoimmune diseases and antigen-specific IgE transgenic mice. TAS05567 inhibited only 4 of 191 kinases tested but inhibited Syk enzymatic activity with high potency. TAS05567 inhibited BCR-dependent signal transduction in Ramos cells, FcR-mediated tumor necrosis factor- production in THP-1 cells, and FcR-mediated histamine release from RBL-2H3 cells. In rheumatoid arthritis models, TAS05567 suppressed hind-paw swelling in a dose-dependent manner compared with vehicle. Moreover, TAS05667 markedly reduced histopathologic scores in an established rat arthritis model. In a mouse immune thrombocytopenic purpura model, platelet counts were reduced with injection of anti-platelet antibody. TAS05567 prevented the platelet count decrease in a dose-dependent manner. Finally, TAS05567 treatment suppressed IgE-mediated ear swelling in vivo. Collectively, our data indicate TAS05567 is a selective Syk inhibitor and potential therapeutic candidate for treating humoral immune-mediated inflammatory conditions such as autoimmune and allergic diseases.

Novel Bruton’s tyrosine kinase inhibitor TAS5315 suppresses the progression of inflammation and joint destruction in rodent collagen-induced arthritis

“…To examine calcium flux, Ramos cells (1×10 6 cells/well) were treated with various concentrations of TAS5315 or DMSO for 30 min under FBS-free conditions before anti-IgM stimulation (5 μg/mL). Intracellular calcium levels were determined using a FLIPR Calcium 5 Assay Kit (Molecular Devices, Sunnyvale, CA, USA), as previously reported [ 29 ].…”

“…For the rat CIA model, experimental arthritis was induced and volumes of both hind paws were measured as previously described [ 29 ]. TAS5315 or prednisolone (1 mg/kg/day) was administered orally for 21 consecutive days from the day of the second immunization.…”

“…For the mouse CIA model, male DBA/1JNCrlj mice (7 weeks old) were injected with complete Freund’s adjuvant (CFA) (BD Biosciences) containing 2 mg/mL of bovine type II collagen at a site on the back (each 0.1 mL) and were boosted 21 days later in a similar manner. Arthritis scores were determined as previously reported [ 29 ]. For histopathological examinations, TAS5315 or prednisolone (3 mg/kg/day) was administered orally for 15 consecutive days from 7th day after the second immunization.…”

“…The specimens were then embedded in paraffin blocks, cut into sections, stained with hematoxylin and eosin, and randomly selected for microscopic examination. Histopathological assessments were performed as described previously [ 29 ]. This experiment was carried out in the laboratory of the BoZo Research Center Inc. (Ibaraki, Japan).…”

Recent and advanced animal models used in the Screening of analgesics and anti-inflammatory activity

“…However, the observation inmorphine sulfate treated animals is only noted at 45 and 60 min. The reaction time was considerably dissimilar between the extract andmorphine sulfate, being better-quality for morphine sulfate at 30, 45, and 60 min after treatment [74].…”