Apolipoprotein E3 (apoE3) safeguards pig proximal tubular LLC-PK1 cells against reduction in SGLT1 activity induced by gentamicin C.
Apolipoprotein E3 (apoE3) safeguards pig proximal tubular LLC-PK1 cells against reduction in SGLT1 activity induced by gentamicin C.
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DOI：
10.1016/j.bbagen.2004.12.006
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发表时间：
2005-04
期刊：
影响因子：
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通讯作者：
K. Takamoto;M. Kawada;D. Ikeda;Motonobu Yoshida
中科院分区：
文献类型：
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作者：
K. Takamoto;M. Kawada;D. Ikeda;Motonobu Yoshida
巨蛋白是一类与低密度脂蛋白受体相关的内吞受体家族，是近端肾小管氨基糖苷蓄积的主要途径。我们以前报道过氨基糖苷类抗生素降低猪近端肾小管上皮LLC-PK1细胞对SGLT1依赖的葡萄糖转运，并与其肾毒性的顺序平行。在这项研究中，使用庆大霉素C(GMC)诱导SGLT1活性降低的模型，我们研究了megalin配体是否保护LLC-PK1细胞免受GMC诱导的SGLT1活性降低。我们使用载脂蛋白E3(ApoE3)和乳铁蛋白作为megalin的配体。然后用不同浓度的载脂蛋白E3、乳铁蛋白和牛血清白蛋白加或不加100μg/mlGMC处理细胞，测定细胞对SGLT1依赖的甲基α-d-葡萄糖苷的摄取和SGLT1的表达水平。因此，我们证明apoE3显著保护这些细胞免受GMC诱导的AMG摄取减少的影响，但乳铁蛋白和白蛋白都不能。与AMG摄取活性增加相一致的是，在apoE3存在下，SGLT1的mRNA和蛋白水平明显上调。此外，我们还发现apoE3降低了庆大霉素的摄取，并且apoE3对依赖GMC的N-乙酰-β-d-葡萄糖胺酶(NAG)的释放有明显的保护作用。因此，这些结果表明apoE3可能是一种有价值的预防氨基糖苷类肾毒性的工具。
Megalin, a family of endocytic receptors related to the low-density lipoprotein (LDL) receptor, is a major pathway for proximal tubular aminoglycoside accumulation. We previously reported that aminoglycoside antibiotics reduce SGLT1-dependent glucose transport in pig proximal tubular epithelial LLC-PK1cells in parallel with the order of their nephrotoxicity. In this study, using a model of gentamicin C (GMC)-induced reduction in SGLT1 activity, we examined whether ligands for megalin protect LLC-PK1cells from the GMC-induced reduction in SGLT1 activity. We employed apolipoprotein E3 (apoE3) and lactoferrin as ligands for megalin. Then the cells were treated with various concentrations of apoE3, lactoferrin and bovine serum albumin with or without 100 μg/ml of GMC, and the SGLT1-dependent methyl α-d-glucopyranoside (AMG) uptake and levels of SGLT1 expression were determined. As a result, we demonstrated that the apoE3 significantly protects these cells from GMC-induced reduction in AMG uptake, but neither lactoferrin nor albumin does. In accord with a rise in AMG uptake activity, the mRNA and protein levels of SGLT1 were apparently up-regulated in the presence of apoE3. Furthermore, we found that the uptake of [3H] gentamicin is decreased by apoE3, and that apoE3 showed obvious protection against the GMC-dependent N-acetyl-β-d-glucosamidase (NAG) release from LLC-PK1cells. Thus, these results indicate that apoE3 could be a valuable tool for the prevention of aminoglycoside nephrotoxicity.