Background/Purpose: Peficitinib and filgotinib are novel Janus kinase (JAK) inhibitors developed for the treatment of rheumatoid arthritis (RA). Peficitinib inhibits all JAKs, especially JAK3. Filgotinib, on the other hand, is a JAK1 selective inhibitor. In this study, to clarify the effect of different JAK inhibition selectivity on angiogenesis in RA fibroblasts, we examined the role of peficitinib and filgotinib in RA angiogenesis.

Methods: In order to confirm if the effect of peficitinib and filgotinib on IL-6 and IL-6R responses in RA fibroblast-like synoviocytes (FLS) and human umbilical vein endothelial cells (HUVECs), western blot analysis was performed. RA FLS and HUVECs were stimulated with IL-6 (100 ng/ml) and IL-6R (100 ng/ml) after treated peficitinib (0.1, 1, 5μM) or filgotinib (0.1, 1, 5μM) for 24 h. Next, to evaluate the effects of peficitinib and filgotinib on RA angiogenesis, we performed in vitro Matrigel tube formation assays using HUVECs. In addition, HUVECs were co-cultured in peficitinib (5 μM) or filgotinib (5 μM) treated RA FLS supernatant, and added on Matrigel. Furthermore, to confirm the direct effects of peficitinib and filgotinib on HUVECs, peficitinib or filgotinib was added to HUVECs supernatant. Finally, to measure the cytokines and chemokines in RA FLS supernatant, RA FLS supernatant was obtained from RA FLS-conditioned medium stimulated with IL-6 (100 ng/ml) and IL-6R (100 ng/ml) with or without adding peficitinib (5 μM) or filgotinib (5 μM). The amount of VEGF, RANTES/CCL5, MCP-1/CCL2, MMP-3, fractalkine/CX3CL1, ENA78/CXCL5 and IL-8 in RA FLS conditioned medium was determined using ELISA.

Results: We found phosphorylation of STAT1, STAT3 and STAT5 in RA FLS was suppressed by peficitinib and filgotinib. However, phosphorylation of STAT3 in HUVEC was not suppressed by filgotinib. Next, peficitinib or filgotinib treated RA FLS conditioned medium reduced HUVEC tube formation compared to nontreated RA FLS conditioned medium (number of endothelial cell tubes formed ± SEM; Control 13.8 ± 1.23, peficitinib 8.5 ± 1.12, filgotinib 8.33 ± 0.73). Filgotinib directry reduced HUVEC tube formation compared to nontreated HUVECs supernatant (Control 7.41 ± 1.04, peficitinib 7.5 ± 0.95, filgotinib 4.58 ± 0.73). Furthermore, we found peficitinib and filgotinib suppress the secretion of VEGF in RA FLS (mean ± SEM; Control: 72.2 ± 1.17, Peficitinib: 42.6 ± 0.26, Filgotinib: 57.35 ± 0.41 pg/ml). Peficitinib significantly suppressed the secretion of VEGF in RA FLS than filgotinib.

Conclusion: Peficitinib and filgotinib suppressed the secretion of VEGF in RA FLS and RA angiogenesis through inhibition of VEGF. Differences in JAK inhibition selectivity of peficitinib and filgotinib affect the suppression of RA angiogenesis.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/peficitinib-and-filgotinib-inhibit-angiogenesis-via-suppression-of-vegf-production-in-rheumatoid-arthritis-fibroblast-like-synoviocytes/