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* = Presenting author

P014 Selective Janus Kinase 1 inhibitor targets monocytes and tissue macrophages during DSS colitis

L. De Vries*1, 2, J. Duarte2, F. Hilbers2, M. De Winther3, P. Moerland4, M. Woodrow5, M. Sims5, V. Ludbrook5, G. D'Haens1, W. De Jonge2

1Academic Medical Center, Gastroenterology & Hepatology, Amsterdam, Netherlands, 2Academic Medical Center, Tytgat Institute for Liver and Intestinal Research, Amsterdam, Netherlands, 3Academic Medical Center, Medical Biochemistry, Amsterdam, Netherlands, 4Academic Medical Center, Clinical Epidemiology, Biostatistics and Bioinformatics, Amsterdam, Netherlands, 5GlaxoSmithKline, Kinase DPU, Stevenage, United Kingdom

Background

Non-selective Janus Kinase inhibitors have shown efficacy in treatment of inflammatory bowel diseases. Janus Kinase 1 inhibitors (JAK1i) interfere with cytokine signaling which is important in both adaptive and innate immune responses. The aim of this study was to investigate the ability of JAK1i to protect mice from an acute Dextran Sulphate Sodium (DSS) colitis, or to ameliorate a chronic DSS colitis. In addition, cellular targets of JAK1i were examined in vitro and in vivo. JAK1i is a selective JAK1 inhibitor (formerly known as GLPG0555) in-licensed by GSK from Galapagos.

Methods

To assess the effect of JAK1i on inflammatory responses, murine bone marrow derived macrophages (BMDM) were stimulated with LPS 100ng/mL and IFNγ 10ng/mL (n=6) of which 3 mice were stimulated in presence of JAK1i. Next, a microarray experiment (Illumina Mouse WG-6 v2) was performed. Genes downregulated by JAK1i were validated in vitro by qPCR. In DSS experiments C57/Bl6 mice (8-12 weeks) were given 2% DSS in drinking water, combined with oral gavage of JAK1i as indicated in figure 1. Clinical and histological inflammation scoring were performed.

Results

In the microarray experiment, JAK1i (1000nM) downregulated 47 LPS/IFNγ-induced genes and upregulated 37 genes (10-300 log2 fold in comparison to LPS/IFNγ treated BMDM). JAK1i left 88 genes unaffected. JAK1i in vitro showed a downregulation of indoleamin 2,3-dioxygenase (IDO1), kynureninase (KYNU) and lymphocyte antigen 6 complex (Ly6a) in comparison to BMDM treated with LPS/IFNγ alone (resp. p = 0.018, 0.002, 0.001). Next, mice were treated with JAK1i in acute DSS colitis. Treatment with 1, 3, 10 and 30 mg/kg JAK1i did not protect mice from weight loss in comparison to DSS treated animals (all p =1). In contrast, JAK1i worsened clinical disease scores in acute and chronic DSS. Colon samples treated with JAK1i showed a decreased expression of IDO1 and KYNU in comparison to DSS treated colon samples, replicating the effects seen in vitro. In chronic DSS, mice treated with 3 mg/kg JAK1i showed a faster weight recovery at day 14 than mice treated with DSS, 10 mg/kg and 30 mg/kg JAK1i. At repetition, weight of mice treated with 3 or 10 mg/kg JAK1i did not ameliorate in comparison to DSS treated mice at day 14 (both p = 1).

ECCOJC jju027 P014 F0001

Conclusion

In vivo, JAK1i did not reduce colitis symptoms and mucosal inflammation in acute and chronic DSS colitis. In vitro, JAK1i affects mediators of the tryptophan catabolism in IFNγ/LPS triggered BMDM, which might attribute to compromised bacterial clearance in this colitis model.