We recently established a role for the stretch-activated two-pore-domain K⁺ (K2P) channel TREK-1 (K2P2.1) in inflammatory cytokine secretion using models of hyperoxia-, mechanical stretch–, and TNF-α–induced acute lung injury. We have now discovered the expression of large conductance, Ca²⁺-activated K⁺ (BK) channels in human pulmonary microvascular endothelial cells and primary human alveolar epithelial cells using semiquantitative real-time PCR, IP and Western blot, and investigated their role in inflammatory cytokine secretion using an LPS-induced acute lung injury model. As expected, LPS induced IL-6 and CCL-2 secretion from pulmonary endothelial and epithelial cells. BK activation with NS1619 decreased LPS-induced CCL-2 but not IL-6 secretion from endothelial cells and had no effect on epithelial cells, although fluorometric assays revealed that BK activation hyperpolarized the plasma membrane potential (Em) of both cell types. Interestingly, BK inhibition (Paxilline) did not alter cytokine secretion or the Em in either cell type. Furthermore, LPS treatment by itself did not affect the Em or intracellular Ca²⁺ concentrations. Therefore, we propose BK channel activation as a novel targeted approach to counteract LPS-induced CCL-2 secretion from endothelial cells. This protective effect appears to occur via Em hyperpolarization but independent of intracellular Ca²⁺ concentrations.

我们最近使用高氧、机械拉伸和 TNF-α 诱导的急性炎症模型，确定了拉伸激活的双孔结构域 K ⁺ (K2P) 通道 TREK-1 (K2P2.1) 在炎症细胞因子分泌中的作用。肺损伤。我们现在使用半定量实时PCR、IP和Western印迹发现了大电导、Ca ²⁺激活的K ⁺ (BK)通道在人肺微血管内皮细胞和原代人肺泡上皮细胞中的表达，并研究了它们在使用 LPS 诱导的急性肺损伤模型观察炎症细胞因子的分泌。正如预期的那样，LPS 诱导肺内皮细胞和上皮细胞分泌 IL-6 和 CCL-2。 NS1619 的 BK 激活减少了 LPS 诱导的内皮细胞的 CCL-2 分泌，但不减少 IL-6 分泌，并且对上皮细胞没有影响，尽管荧光测定显示 BK 激活使两种细胞类型的质膜电位 (Em) 超极化。有趣的是，BK 抑制（Paxilline）不会改变任一细胞类型中的细胞因子分泌或 Em。此外，LPS 处理本身并不影响 Em 或细胞内 Ca ²⁺浓度。因此，我们提出 BK 通道激活作为一种新的靶向方法来抵消 LPS 诱导的内皮细胞分泌 CCL-2。这种保护作用似乎是通过 Em 超极化发生的，但与细胞内 Ca ²⁺浓度无关。