Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale University School of Medicine , New Haven, Connecticut.
Department of Urology, Yale University School of Medicine , New Haven, Connecticut.
Am J Physiol Renal Physiol. 2019 Apr 1;316(4):F617-F623. doi: 10.1152/ajprenal.00554.2018. Epub 2019 Jan 16.
The open probability of calcium-activated voltage-gated potassium channel (BK channel) on bladder umbrella urothelial cells is increased by lipopolysaccharide (LPS). It is hypothesized that this channel's activity is important in the urothelial innate immune response during urinary tract infection (UTI). We performed in vivo studies using female C57BL/6 mice whose bladders were inoculated with LPS (150 μl of 1 mg/ml) or uropathogenic Escherichia coli (UPEC, UTI89), without and with intravesical BK inhibitor iberiotoxin (IBTX, 1 μM). Inflammatory biomarkers (chemokines and cytokines) were measured in urine specimens collected 2 h after inoculation using a 32-multiplex ELISA. Of these 32 biomarkers, 19 and 15 were significantly elevated 2 h after LPS and UPEC exposure, respectively. IBTX significantly abrogated the elevations of 15 out of 19 biomarkers after LPS inoculation and 12 out of 15 biomarkers after UPEC inoculation. In a separate experiment, qPCR for IL-6, interferon-γ-induced protein 10 (CXCL10), and macrophage inflammatory protein 2 (CXCL2) in urothelium paralleled the changes measured in urine of these same biomarkers, supporting that urinary changes in biomarker levels reflected urothelial expression changes. These in vivo data demonstrated that BK channel activity is crucial in the urothelial host innate immune response, as measured by changes in urinary biomarkers, in UTI pathogenesis.
膀胱伞状尿路上皮细胞的钙激活电压门控钾通道（BK 通道）的开放概率可被脂多糖（LPS）增加。假设该通道的活性在尿路感染（UTI）期间尿路上皮固有免疫反应中很重要。我们使用雌性 C57BL/6 小鼠进行了体内研究，这些小鼠的膀胱接种了 LPS（150 μl 浓度为 1 mg/ml）或尿路致病性大肠杆菌（UPEC，UTI89），并在膀胱内给予 BK 抑制剂 Iberiotoxin（IBTX，1 μM）。在接种后 2 小时收集尿液标本，使用 32 多重 ELISA 测量炎性生物标志物（趋化因子和细胞因子）。在这 32 个生物标志物中，有 19 个和 15 个在 LPS 和 UPEC 暴露后 2 小时分别显著升高。IBTX 显著消除了 LPS 接种后 19 个生物标志物中的 15 个和 UPEC 接种后 15 个生物标志物中的 12 个的升高。在另一个实验中，qPCR 检测到的 IL-6、干扰素-γ诱导蛋白 10（CXCL10）和巨噬细胞炎症蛋白 2（CXCL2）在尿路上皮中的表达变化与这些相同生物标志物在尿液中的变化一致，支持尿液中生物标志物水平的变化反映了尿路上皮表达的变化。这些体内数据表明，BK 通道活性在 UTI 发病机制中，作为尿路上皮固有免疫反应的生物标志物改变，在尿路上皮固有免疫反应中至关重要。
