Kraya Ramsey, Komin Alexander, Searson Peter
IEEE Trans Nanobioscience. 2016 Oct;15(7):697-703. doi: 10.1109/TNB.2016.2604322.
Bioelectric impedance spectroscopy was used to elucidate the influence of P-gp efflux pumps on the kinetics of tight junction down-regulation in confluent monolayers of Madine Darby Canine Kidney Epithelial Cells (MDCK) following administration of phenylarsine oxide (PAO), a molecule that inhibits protein tyrosine phosphatases (PTP) and induces matrix metalloproteinase activity. Matrix metalloproteinases (MMPs) and phosphatase inhibitors induce modification of occludin tight junction proteins critical for the proper function of the blood-brain barrier. The addition of PAO to MDCKII cell lines resulted in a dramatic decrease in monolayer resistance. In contrast, MDCKII-MDR1 cells transfected with the MDR1 gene treated with PAO showed an initial decrease in monolayer resistance followed by a partial recovery and subsequent decrease. This resistance decay reversal was suppressed with the addition of the P-glycoprotein (P-gp) pump inhibitor elacridar, and is attributed to PAO efflux. These results illustrate impedance spectroscopy can be used to characterize the competing kinetics of efflux and down-regulation of tight junctions. In addition, the resistance decay reversal effect can be used to evaluate P-gp pump inhibitor efficacy.
生物电阻抗光谱法被用于阐明P-糖蛋白外排泵对马-达二氏犬肾上皮细胞（MDCK）汇合单层中紧密连接下调动力学的影响，该单层细胞在给予氧化苯胂（PAO）后，PAO是一种抑制蛋白酪氨酸磷酸酶（PTP）并诱导基质金属蛋白酶活性的分子。基质金属蛋白酶（MMPs）和磷酸酶抑制剂会诱导闭合蛋白紧密连接蛋白发生修饰，而闭合蛋白对血脑屏障的正常功能至关重要。向MDCKII细胞系中添加PAO会导致单层电阻显著降低。相比之下，用PAO处理的转染了MDR1基因的MDCKII-MDR1细胞显示单层电阻最初降低，随后部分恢复，接着再次降低。添加P-糖蛋白（P-gp）泵抑制剂艾拉司群可抑制这种电阻衰减逆转，这归因于PAO的外排。这些结果表明，阻抗光谱法可用于表征紧密连接外排和下调的竞争动力学。此外，电阻衰减逆转效应可用于评估P-gp泵抑制剂的疗效。
