Suppressing Kv1.3 Ion Channel Activity with a Novel Small Molecule Inhibitor Ameliorates Inflammation in a Humanised Mouse Model of Ulcerative Colitis

Abstract

Background and Aims The potassium channel Kv1.3 is a potentially attractive therapeutic target in T cell-mediated inflammatory diseases, as the activity of antigen-activated T cells is selectively impeded by Kv1.3 inhibition. In this study, we examined Kv1.3 as a potential therapeutic intervention point for ulcerative colitis (UC), and studied the efficacy of DES1, a small-molecule inhibitor of Kv1.3, in vitro and in vivo. Methods Kv1.3 expression on T cells in peripheral blood mononuclear cells (PBMCs) isolated from donors with and without UC was examined by flow cytometry. In biopsies from UC patients, Kv1.3-expressing CD4+ T cells were detected by flow cytometry and immunohistochemistry. In vitro, we determined the ability of DES1 to inhibit anti-CD3-driven activation of T cells. In vivo, the efficacy of DES1 was determined in a humanized mouse model of UC and compared to infliximab and tofacitinib in head-to-head studies. Results Kv1.3 expression was elevated in PBMCs from UC patients and correlated with the prevalence of TH1 and TH2 T cells. Kv1.3 expression was also detected on T cells from biopsies of UC patients. In vitro, DES1 suppressed anti-CD3-driven activation of T cells in a concentration-dependent manner. In vivo, DES1 significantly ameliorated inflammation in the UC model and most effectively so when PBMCs from donors with higher levels of activated T cells were selected for reconstitution. The efficacy of DES1 was comparable to that of either infliximab or tofacitinib. Conclusion Inhibition of Kv1.3 (by DES1, for instance) appears to be a potential therapeutic intervention strategy for UC patients.

Ion channel regulation of gut immunity

“…In general, the translation of findings from animal models to clinical practice has not been very successful. Therefore, experimental designs of preclinical animal studies need to be improved and humanized animal models of GI disorders might enhance translational potentials ( Unterweger et al, 2021 ). This is especially exciting because ongoing high throughput drug screening has identified numerous activators and inhibitors that have the potential to be used in the treatment of GI inflammatory disorders by targeting ion channels such as Orai channels, Kv1.3, P2X7R, and nAChR, which are the most important channels in gut immunity that have emerged over the past decades.…”

“…This is especially exciting because ongoing high throughput drug screening has identified numerous activators and inhibitors that have the potential to be used in the treatment of GI inflammatory disorders by targeting ion channels such as Orai channels, Kv1.3, P2X7R, and nAChR, which are the most important channels in gut immunity that have emerged over the past decades. Among them, Orai channels, Kv1.3 are the most promising ion channel drug targets for the treatment of IBD as shown by recent preclinical studies ( Unterweger et al, 2021 ; Letizia et al, 2022 ). On the other hand, it remains a big challenge to target distinct cell types when the same ion channels are expressed by various tissues in the gut to avoid any off-target side effects and toxicity issues associated with ion channel activators and blockers.…”

“…As Kv1.3 loss-of-function in mice is lethal, functional studies are mainly dependent on pharmacological tools. Inhibition of Kv1.3 expressed by CD4 + T cells with a small molecule inhibitor DES1 suppresses intestinal inflammation in a humanized mouse model of UC ( Unterweger et al, 2021 ). Another Kv1.3 blocker PAP-1 also protects animals against DSS-induced colitis possibly through inhibition of NLRP3 inflammasome pathway downstream of Kv1.3 signaling ( Mei et al, 2019 ).…”

The potassium channel Kv1.3 as a therapeutic target for immunocytoprotection after reperfusion

“…The pharmacological tool compound we used here, PAP‐1, has undergone IND‐enabling toxicity studies for psoriasis and could potentially be used in humans. Several new Kv1.3 inhibitors are also currently in preclinical development 43 and could become available for combination with EVT.…”

Tofacitinib fails to prevent T cell transfer colitis in mice but ameliorates disease activity

“…All published models are primarily models of chemically induced colitis (either DSS or oxazolone) 6-10 . One very recently publication included a humanized model 11 . To investigate the clinical effect of tofacitinib in mice, we performed a CD4 + transfer colitis into lymphogenic Rag2-/-mice and treated the mice with tofacitinib dissolved in the drinking water.…”