PDF(Pubmed)
Abstract：
The polarised expression of specific transporters in proximal tubular epithelial cells is important for the renal clearance of many endogenous and exogenous compounds. Thus, ideally, the in vitro tools utilised for predictions would have a similar expression of apical and basolateral xenobiotic transporters as in vivo. Here, we assessed the functionality of organic cation and anion transporters in proximal tubular-like cells (PTL) differentiated from human induced pluripotent stem cells (iPSC), primary human proximal tubular epithelial cells (PTEC), and telomerase-immortalised human renal proximal tubular epithelial cells (RPTEC/TERT1). Organic cation and anion transport were studied using the fluorescent substrates 4-(4-(dimethylamino)styryl)-N-methylpyridinium iodide (ASP) and 6-carboxyfluorescein (6-CF), respectively. The level and rate of intracellular ASP accumulation in PTL following basolateral application were slightly lower but within a 3-fold range compared to primary PTEC and RPTEC/TERT1 cells. The basolateral uptake of ASP and its subsequent apical efflux could be inhibited by basolateral exposure to quinidine in all models. Of the three models, only PTL showed a modest preferential basolateral-to-apical 6-CF transfer. These results show that organic cation transport could be demonstrated in all three models, but more research is needed to improve and optimise organic anion transporter expression and functionality.
摘要：
近端肾小管上皮细胞中特定转运蛋白的极化表达对于许多内源性和外源性化合物的肾清除很重要。因此，理想情况下,用于预测的体外工具将具有与体内相似的顶端和基底外侧异种生物转运蛋白表达。这里,我们评估了从人诱导多能干细胞（iPSC）分化的近端肾小管样细胞（PTL）中有机阳离子和阴离子转运蛋白的功能，原代人近端肾小管上皮细胞（PTEC），和端粒酶永生化人肾近端肾小管上皮细胞（RPTEC/TERT1）。使用荧光底物4-（4-（二甲基氨基）苯乙烯基）-N-甲基吡啶碘化物（ASP）和6-羧基荧光素（6-CF）研究了有机阳离子和阴离子的迁移，分别。与原代PTEC和RPTEC/TERT1细胞相比，基底外侧施用后PTL中细胞内ASP积累的水平和速率略低，但在3倍范围内。在所有模型中，基底外侧暴露于奎尼丁都可以抑制ASP的基底外侧吸收及其随后的顶端外排。在这三个模型中，只有PTL显示适度的基底外侧至根尖6-CF转移。这些结果表明，有机阳离子运输可以在所有三个模型中得到证明，但是需要更多的研究来改善和优化有机阴离子转运蛋白的表达和功能。
