Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto, Japan; Department of Molecular & Cellular Pharmacology, Nagoya City University, Nagoya, Japan;
Department of Molecular & Cellular Pharmacology, Nagoya City University, Nagoya, Japan;
Am J Physiol Gastrointest Liver Physiol. 2014 May 15;306(10):G873-85. doi: 10.1152/ajpgi.00156.2013. Epub 2014 Mar 27.
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.
中等电导钙激活钾通道 KCa3.1/KCNN4 通过调节 T 淋巴细胞的膜电位在钙信号转导的调节中发挥重要作用。在这里，我们研究了 KCa3.1 在炎症性肠病 (IBD) 小鼠模型中肠系膜淋巴结 (MLN) 增大中的作用。通过用 5%葡聚糖硫酸钠暴露雄性 C57BL/6J 小鼠 7 天来制备 IBD 小鼠模型。通过实时 PCR、Western blot、电压敏感染料成像、膜片钳和流式细胞术分析监测 MLN CD4(+)T 淋巴细胞中 KCa3.1 活性和 KCa3.1 及其调节剂的表达变化。与 KCa3.1a 和核苷二磷酸激酶 B (NDPK-B) 的上调同时发生，一种阳性的 KCa3.1 调节剂，在 IBD 模型中的 MLN CD4(+)T 淋巴细胞中观察到 KCa3.1 活性增加。KCa3.1 的药理学阻断产生了以下结果：1)与对照小鼠相比，IBD 疾病严重程度显著降低，如腹泻、可见粪便血、炎症和结肠隐窝损伤以及 MLN 增大，2)IBD 模型 MLN CD4(+)T 淋巴细胞中 KCa3.1a、NDPK-B 和 Th1 细胞因子的表达水平恢复。这些发现表明，KCa3.1a 和 NDPK-B 的上调引起的 KCa3.1 活性增加可能通过介导 MLN CD4(+)T 淋巴细胞增殖反应的增强而参与 IBD 的发病机制，因此，KCa3.1 的药理学阻断可能降低 IBD 的风险。
