Blocking Jak/STAT signalling using tofacitinib inhibits angiogenesis in experimental arthritis

Abstract

Objective During rheumatoid arthritis (RA), the angiogenic processes, occurring with pannus-formation, may be a therapeutic target. JAK/STAT-pathway may play a role and the aim of this work was to investigate the inhibiting role of a JAK-inhibitor, tofacitinib, on the angiogenic mechanisms occurring during RA. Methods After ethical approval, JAK-1, JAK-3, STAT-1, STAT-3 and VEGF expression was evaluated on RA-synovial-tissues. In vitro, endothelial cells (ECs), stimulated with 20 ng/ml of VEGF and/or 1 μM of tofacitinib, were assessed for tube formation, migration and proliferation, by Matrigel, Boyden chamber assay and ki67 gene-expression. In vivo, 32 mice received collagen (collagen-induced arthritis (CIA)) and 32 mice PBS (control). At day 19, CIA and controls mice were divided: 16 mice receiving vehicle and 16 mice receiving tofacitinib. At day 35, the arthritis score, the thickness of paw joints and the serum levels of VEGF and Ang-2 were evaluated. Results The expression of JAK-1, JAK-3, STAT-1, STAT-3 and VEGF in synovial tissue of RA-patients were significantly higher than healthy controls. In vitro, tofacitinib inhibited the ECs ability to form vessels, to proliferate and to migrate. In vivo, administration of tofacitinib prevented the increase of the arthritis score, the paw thickness, the synovial vessels and VEGF and Ang-2 serum-accumulation, when compared to CIA without tofacitinib. Conclusions We explored the anti-angiogenic role of tofacitinib, reporting its ability to inhibit in vitro the angiogenic mechanisms of ECs and in vivo the formation of new synovial vessels, occurring in CIA model. These findings suggest that the therapeutic effect of tofacitinib during RA may be also related to its anti-angiogenic activity.

Tofacitinib May Inhibit Myofibroblast Differentiation from Rheumatoid-Fibroblast-like Synoviocytes Induced by TGF-β and IL-6

“…However, the Western blot analysis did not fully confirm this finding, highlighting the need of further studies to entirely clarify this topic. Probably, a longer time of stimulation with tofacitinib might confirm the results of the RT-PCR with the Western blot analysis as well [ 17 , 18 , 19 ].…”

“…In fact, TGF-β and IL-6 decreased E-Cad, which is an important component of extracellular connections, and its down-regulation may facilitate RA-FLSs migration and invasion [ 5 , 20 ]. Furthermore, TGF-β and IL-6 increased collagen I and α-SMA, which are markers of myofibroblast differentiation and activation [ 7 , 16 , 18 , 19 ]. Thus, an activated phenotype of RA-FLSs may be induced by these molecules, supporting the hypothesis that a process of EMT may be involved in the pathogenesis of the disease [ 23 , 24 ].…”

“…Tofacitinib is a targeted small molecule inhibitor of several JAK isoforms, especially JAK3 and JAK1, and its inhibition of signal transduction may influence the cellular response to the inflammatory environment [ 12 , 13 , 14 , 15 , 16 ]. As observed in other diseases [ 16 , 17 , 18 , 19 , 20 , 21 , 22 ], tofacitinib could also exert its therapeutic effects via an inhibition of myofibroblast differentiation from RA-FLSs, although it has not been fully elucidated yet. On these bases, in this study, we aimed to assess the markers of myofibroblast differentiation of RA-FLSs by ex vivo observations and in vitro evaluations following the stimulation with both TGF-β and IL-6.…”

Stat3 Signaling Pathway: A Future Therapeutic Target for Bone-Related Diseases

“…In addition, Stat3 signaling pathway can be indirectly suppressed by blocking upstream regulators such as IL-6, JAK and EGF ( Yu et al, 2018 ; Di Benedetto et al, 2021 ; Zhou et al, 2021 ). AG490 and tofacitinib are JAK tyrosine kinase inhibitors, which are widely studied as JAK2 inhibitors in immune and inflammatory diseases ( Chen et al, 2019 ).…”

Molecular and Cellular Heterogeneity in Rheumatoid Arthritis: Mechanisms and Clinical Implications

“…Spebrutinib (CC-292), a Bruton's tyrosine kinase inhibitor, can inhibit B cell proliferation and osteoclast production in vitro and can reduce the number of CD19B cells, serum CXCL13, macrophage inflammatory protein-1b (MIP-1b), carboxy-terminal collagen cross-linking telopeptide, and Ctelopeptide of type I collagen (CTx-1), among which CD19B cells and CTx-1 can predict the response of RA patients to spebrutinib (234). Tofacitinib, a JAK inhibitor, can inhibit the angiogenesis and migration ability of endothelial cells (ECs) in vitro and reduce VEGF levels in CIA mice, suggesting that its efficacy could be related to angiogenic inhibition (235). A randomized, double-blind, phase II clinical trial tested the effect of 10 mg of tofacitinib twice daily on patients with poor MTX response for 28 days.…”