Upregulation of K_Ca3.1 K⁺ channel in mesenteric lymph node CD4⁺ T lymphocytes from a mouse model of dextran sodium sulfate-induced inflammatory bowel disease

Abstract

The intermediate-conductance Ca(2+)-activated K(+) channel KCa3.1/KCNN4 plays an important role in the modulation of Ca(2+) signaling through the control of the membrane potential in T lymphocytes. Here, we study the involvement of KCa3.1 in the enlargement of the mesenteric lymph nodes (MLNs) in a mouse model of inflammatory bowel disease (IBD). The mouse model of IBD was prepared by exposing male C57BL/6J mice to 5% dextran sulfate sodium for 7 days. Inflammation-induced changes in KCa3.1 activity and the expressions of KCa3.1 and its regulators in MLN CD4(+) T lymphocytes were monitored by real-time PCR, Western blot, voltage-sensitive dye imaging, patch-clamp, and flow cytometric analyses. Concomitant with an upregulation of KCa3.1a and nucleoside diphosphate kinase B (NDPK-B), a positive KCa3.1 regulator, an increase in KCa3.1 activity was observed in MLN CD4(+) T lymphocytes in the IBD model. Pharmacological blockade of KCa3.1 elicited the following results: 1) a significant decrease in IBD disease severity, as assessed by diarrhea, visible fecal blood, inflammation, and crypt damage of the colon and MLN enlargement compared with control mice, and 2) the restoration of the expression levels of KCa3.1a, NDPK-B, and Th1 cytokines in IBD model MLN CD4(+) T lymphocytes. These findings suggest that the increase in KCa3.1 activity induced by the upregulation of KCa3.1a and NDPK-B may be involved in the pathogenesis of IBD by mediating the enhancement of the proliferative response in MLN CD4(+) T lymphocyte and, therefore, that the pharmacological blockade of KCa3.1 may decrease the risk of IBD.

Inhibition of Interleukin 10 Transcription through the SMAD2/3 Signaling Pathway by Ca2+-Activated K+Channel KCa3.1 Activation in Human T-Cell Lymphoma HuT-78 Cells

“…The intermediate-conductance Ca 21 -activated K 1 channel K Ca 3.1 plays an important role in the control of proinflammatory cytokine production and secretion by regulating Ca 21 signaling in lymphoid and myeloid cells (Di et al, 2010;Ohya et al, 2014); however, it currently remains unclear whether K Ca 3.1 contributes to IL-10-induced escape from cancer immune surveillance. The present study showed that the pharmacological blockade of K Ca 3.1 by 1 mM TRAM-34 did not evoke depolarization responses in human T-cell lymphoma HuT-78 cells under resting conditions (Fig.…”

“…A whole-cell patch clamp was applied to single HuT-78 cells using the CEZ-2400 amplifier (Nihon Kohden, Tokyo, Japan) at room temperature (23°C 6 1°C). The procedures used for electrophysiological recordings and data acquisition/analysis have been reported previously (Ohya et al, 2014).…”

“…K Ca 3.1 plays a pivotal role in the proliferation, differentiation, and migration of immune cells and is a potential therapeutic target for autoimmune and inflammatory disorders. In addition, the enhancement of K Ca 3.1 activity promotes proinflammatory cytokine production and secretion by regulating Ca 21 signaling in CD4 1 T cells (Di et al, 2010;Ohya et al, 2014). In CD8 1 T cells with the capacity to kill malignant cells, K 1 efflux-mediating K Ca 3.1 activation increases antitumor function by promoting interferon (IFN)-g production (Eil et al, 2016).…”

Role of epithelial ion transports in inflammatory bowel disease

“…In fact IK are, alongside K v 1.3 (73), crucial for T cell activation and proliferation: they keep an electrical gradient that allows Ca 2ϩ influx, which is a required step for the translocation of the nuclear factor of activated T cells (NFAT) to the nucleus, ultimately resulting in cytokine secretion and T cell proliferation (20,62). Given that IBD is a T cell-driven disease, it is unsurprising that inhibition of lymphocytic IK channels reduces inflammation and colitis manifestations, and therefore IK blockade has received considerable attention as a potential therapeutic target (38,53,106,132 …”

Ca²⁺-Activated K⁺ Channel K_Ca3.1 as a Therapeutic Target for Immune Disorders

“…6) Pharmacological blockade of K Ca 3.1 reduces the expression and secretion of pro-inflammatory cytokines and chemokines. [6][7][8] Therefore, K Ca 3.1 is an attractive therapeutic target for multiple sclerosis (MS), rheumatoid arthritis (RA), inflammatory bowel disease (IBD), asthma, atherosclerosis, allergic rhinitis, and various tissue fibrosis. 1) In addition, auxiliary subunits that positively or negatively control K Ca 3.1 activity, as well as transcriptional and post-transcriptional regulators that control K Ca 3.1 gene expression, have been identified: i) phosphoinositide-3-kinase, class 2, β polypeptide (PI3K-C2B), nucleoside diphosphate kinase-B (NDPK-B), phosphohistidine phosphatase 1 (PHPT-1), myotubularin related protein 6 (MTMR6), tripartite motif containing 27 (TRIM-27), and phosphoglycerate mutase family member 5 (PGAM5) as auxiliary subunits, [9][10][11][12][13] and ii) activating protein-1 (AP-1), repressor element 1-silencing transcription factor (REST/NRSF), histone deacetylase 2/3 (HDAC2/3), and microRNA-497-5p (miR-497-5p) as transcriptional and post-transcriptional regulators.…”