Transcellular transport of radioiodinated 3-iodo-α-methyl-L-tyrosine across monolayers of kidney epithelial cell line LLC-PK1
Transcellular transport of radioiodinated 3-iodo-α-methyl-L-tyrosine across monolayers of kidney epithelial cell line LLC-PK1
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放射性碘化 3-碘-α-甲基-L-酪氨酸跨肾上皮细胞系 LLC-PK1 单层的跨细胞转运
DOI：
10.1007/bf02985004
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发表时间：
2004
影响因子：
2.6
通讯作者：
H. Saji
中科院分区：
文献类型：
--
作者：
N. Shikano;K. Kawai;Syuichi Nakajima;A. Kubodera;N. Kubota;Nobuyoshi Ishikawa;H. Saji
目的：3-[123I]碘-α-甲基-L-酪氨酸([123I]IMT)是一种氨基酸转运显像剂。为了获得与[123I]IMT肿瘤显像和[123I]IMT在肾脏的生理蓄积相关的基础数据，我们利用生长在微孔滤膜上的细胞单层研究了[123I]IMT在猪肾上皮细胞系LLC-PKI中的转运特性。方法：在胶原膜(3μm)上构建LLC-PKI单分子膜。为了检测跨细胞转运(分泌和重吸收)和积累，将单层在37℃下与18.5kBq[125I]IMT在Dulbecco的磷酸盐缓冲盐水(pH 7.4)中孵育90分钟作为摄取液。孵育后，通过量化单层两侧溶液的放射性来评估跨细胞转运。在蓄积实验中，将细胞溶解在氢氧化钠溶液中，并对其放射性进行定量。在缓蚀实验中，缓蚀剂的最终浓度为1 mM。在pH依赖性实验中，顶侧摄取液的pH值从5变化到pH 8。比较了[14C]Tyr的转运情况。结果：观察到[125I]IMT的双向跨细胞转运，对应于近端小管的分泌和重吸收。90min时，从基底外侧(1.62±0.15%)和根尖侧(2.62±0.35%)可见[125I]IMT积聚。2-氨基双环[2，2，1]庚烷-2-羧酸(L系统的特异性抑制剂)、L-酪氨酸([125I]IMT的母体化合物)和2-氨基异丁酸(L和A系统的抑制剂)既抑制定向转运(p<；0.01)，又抑制蓄积(p<；0.01)。2-甲氨基异丁酸(A系统的特异性抑制剂)似乎抑制了转运和积累，但结果并不显著。降低根尖pH可显著促进[125I]IMT自两侧的转运(p<；0.001)，而母体L-酪氨酸的转运则受到明显抑制。结论：抑制实验表明，在根尖和基底外侧膜上，[125I]IMT转运的主要贡献者是L系统，而不是钠离子依赖的转运。[125I][125I]IMT是通过转运L-Tyr的系统转运的，但观察到的转运的pH依赖性表明，[125I]IMT和[14C]Tyr的积累涉及不同的机制。
Objective: 3-[123I]iodo-α-methyl-L-tyrosine ([123I]IMT) is an imaging agent for amino acid transport. In order to obtain fundamental data related to tumor imaging with [123I]IMT and renal physiological accumulation of [123I]IMT, we investigated the transport characteristics of [123I]IMT in porcine kidney epithelial cell line LLC-PKi using cell monolayers grown on microporous membrane filters.Methods: LLC-PKi monolayers were created on a collagen-coated microporous (3μm) membrane (4.7 cm2). To examine transcellular transport (secretion and reabsorption) and accumulation, the monolayers were incubated for up to 90 min at 37°C with 18.5 kBq [125I]IMT in Dulbecco’s phosphate-buffered saline (pH 7.4) as an uptake solution. After incubation, transcellular transport was assessed by quantifying the radioactivity of the solutions on each side of the monolayer. For the accumulation experiment, the cells were solubilized in NaOH solution, and the radioactivity was quantified. For the inhibition experiment, the inhibitor was added at a final concentration of 1 mM. For the pH dependence experiment, the pH of the apical-side uptake solution was varied from pH 5 to pH 8. Transport of [14C]Tyr was examined for comparison.Results: Bi-directional transcellular transport of [125I]IMT was observed, corresponding to secretion and reabsorption in proximal tubule. Accumulation of [125I]IMT from the basolateral side (1.62 ± 0.15%) and the apical side (2.62 ± 0.35%) was observed at 90 min. 2-Amino-bicyclo[2,2,1]heptane-2-carboxylic acid (a specific inhibitor of system L), L-Tyr (mother compound of [125I]IMT) and 2-aminoisobutyric acid (an inhibitor of system L and A) inhibited both directional transport (p < 0.01) and accumulation (p < 0.01). 2-(Methylamino)isobutyric acid (a specific inhibitor of system A) appeared to inhibit transport and accumulation, but the results were not significant. Decreasing apical pH significantly enhanced accumulation of [125I]IMT from both sides (p < 0.001), whereas accumulation of mother L-Tyr was significantly suppressed.Conclusions: The inhibition experiments suggest that the main contributor to [125I]IMT transport is system L, rather than Na+-dependent transport, in both apical and basolateral membrane. [125I]IMT was transported by the system that transported L-Tyr, but the observed pH dependence of transport suggests that different mechanisms are involved in accumulation of [125I]IMT and [14C]Tyr.
具有近端肾小管细胞特征的肾细胞系 (LLC-PK1) 中的闭塞连接。
DOI：
10.1152/ajprenal.1986.250.4.f734
发表时间：
1986
期刊：
The American journal of physiology
影响因子：
--
作者：
Rabito,CA
通讯作者：
Rabito,CA
中国仓鼠卵巢细胞中的中性氨基酸转运系统。
DOI：
--
发表时间：
1981
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Shotwell,MA;Jayme,DW;Kilberg,MS;Oxender,DL
通讯作者：
Oxender,DL
肾源性上皮细胞系 (LLC-PK1) 的极化氨基酸转运。
DOI：
--
发表时间：
1983
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Rabito,CA;Karish,MV
通讯作者：
Karish,MV