Suppression of NFAT5-mediated Inflammation and Chronic Arthritis by Novel κB-binding Inhibitors

Abstract

Nuclear factor of activated T cells 5 (NFAT5) has been implicated in the pathogenesis of various human diseases, including cancer and arthritis. However, therapeutic agents inhibiting NFAT5 activity are currently unavailable. To discover NFAT5 inhibitors, a library of > 40,000 chemicals was screened for the suppression of nitric oxide, a direct target regulated by NFAT5 activity, through high-throughput screening. We validated the anti-NFAT5 activity of 198 primary hit compounds using an NFAT5-dependent reporter assay and identified the novel NFAT5 suppressor KRN2, 13-(2-fluoro)-benzylberberine, and its derivative KRN5. KRN2 inhibited NFAT5 upregulation in macrophages stimulated with lipopolysaccharide and repressed the formation of NF-κB p65-DNA complexes in the NFAT5 promoter region. Interestingly, KRN2 selectively suppressed the expression of pro-inflammatory genes, including Nos2 and Il6, without hampering high-salt-induced NFAT5 and its target gene expressions. Moreover, KRN2 and KRN5, the latter of which exhibits high oral bioavailability and metabolic stability, ameliorated experimentally induced arthritis in mice without serious adverse effects, decreasing pro-inflammatory cytokine production. Particularly, orally administered KRN5 was stronger in suppressing arthritis than methotrexate, a commonly used anti-rheumatic drug, displaying better potency and safety than its original compound, berberine. Therefore, KRN2 and KRN5 can be potential therapeutic agents in the treatment of chronic arthritis.

A miRNA181a/NFAT5 axis links impaired T cell tolerance induction with autoimmune type 1 diabetes

“…A recently identified compound was shown to block the proinflammatory NFAT5 activity by inhibiting Nfat5 transcriptional activation without affecting NFAT1 to NFAT4, nuclear factor κB (NF-κB), p38 mitogen-activated protein kinase, and cAMP (adenosine 3′,5′-monophosphate) response element–binding protein (CREB) activity, excluding potential off-target effects (36). NFAT5 inhibition improved murine and human T reg induction (Fig.…”

“…A small-molecule inhibitor of NFAT5, developed by W.-U.K. (36), was added simultaneously to the TCR stimulation at a concentration of 0.01 μM or 0.01 nM in case of low-dose anti-CD3 stimulation.…”

Genetic ablation of NFAT5/TonEBP in smooth muscle cells impairs flow‐ and pressure‐induced arterial remodeling in mice

“…9). As first pharmacological inhibitors of NFAT5 are meanwhile available (66), which appear to preserve its renal atrophy, preventing osmoprotective functions (67), it is tempting to speculate that corresponding drugs antagonize detrimental vascular remodeling processes.…”

Transcription Factor NFAT5 Promotes Migration and Invasion of Rheumatoid Synoviocytes via Coagulation Factor III and CCL2

“…However, therapeutic agents that emasculate the aggressive phenotype of RA-FLSs have not been tried. Previously, we identified the novel NFAT5 inhibitor KRN2, 13-(2-fluorobenzyl)-berberine, through high-throughput drug screening (35). KRN2 selectively inhibited the transcriptional activation of NFAT5 by blocking NF-kB binding to the NFAT5 promoter region, reducing the expression of proinflammatory genes (35).…”

“…Recently, we identified a novel NFAT5 suppressor, KRN2, 13-(2-fluorobenzyl)-berberine, to selectively inhibit NFAT5 expression in RAW 264.7 macrophages (35). We tested whether KRN2 suppresses NFAT5 expression and cell migration in mouse FLSs.…”