Tomás Mónica, Lázaro-Diéguez Francisco, Durán Juan M, Marín Pilar, Renau-Piqueras Jaime, Egea Gustavo
Centro de Investigación, Hospital La Fe, Valencia, Spain.
J Neurochem. 2003 Oct;87(1):220-9. doi: 10.1046/j.1471-4159.2003.01993.x.
Ethanol induces severe alterations in membrane trafficking in hepatocytes and astrocytes, the molecular basis of which is unclear. One of the main candidates is the cytoskeleton and the molecular components that regulate its organization and dynamics. Here, we examine the effect of chronic exposure to ethanol on the organization and dynamics of actin and microtubule cytoskeletons and glucose uptake in rat astrocytes. Ethanol-treated cells cultured in either the presence or absence of fetal calf serum showed a significant increase in 2-deoxyglucose uptake. Ethanol also caused alterations in actin organization, consisting of the dissolution of stress fibres and the appearance of circular filaments beneath the plasma membrane. When lysophosphatidic acid (LPA), which is a normal constituent of serum and a potent intercellular lipid mediator with growth factor and actin rearrangement activities, was added to ethanol-treated astrocytes cultured without fetal calf serum, it induced the re-appearance of actin stress fibres and the normalization of 2-deoxyglucose uptake. Furthermore, ethanol also perturbed the microtubule dynamics, which delayed the recovery of the normal microtubule organization following removal of the microtubule-disrupting agent nocodazole. Again, pre-treatment with LPA prevented this alteration. Ethanol-treated rodent fibroblast NIH3T3 cells that constitutively express an activated Rho mutant protein (GTP-bound form) were insensitive to ethanol, as they showed no alteration either in actin stress-fibre organization or in 2-deoxyglucose uptake. We discuss the putative signalling targets by which ethanol could alter the cytoskeleton and hexose uptake and the cytoprotective effect of LPA against ethanol-induced damages. The latter opens the possibility that LPA or a similar non-hydrolysable lipid derivative could be used as a cytoprotective agent against the noxious effects of ethanol.
乙醇会引起肝细胞和星形胶质细胞中膜运输的严重改变，其分子基础尚不清楚。主要候选因素之一是细胞骨架以及调节其组织和动态的分子成分。在此，我们研究了长期暴露于乙醇对大鼠星形胶质细胞中肌动蛋白和微管细胞骨架的组织和动态以及葡萄糖摄取的影响。在有或没有胎牛血清存在的情况下培养的经乙醇处理的细胞，其2-脱氧葡萄糖摄取量显著增加。乙醇还导致肌动蛋白组织发生改变，表现为应力纤维溶解以及质膜下出现环形细丝。当将溶血磷脂酸（LPA）添加到在无胎牛血清条件下培养的经乙醇处理的星形胶质细胞中时（LPA是血清的正常成分，是一种具有生长因子和肌动蛋白重排活性的强效细胞间脂质介质），它诱导了肌动蛋白应力纤维的重新出现以及2-脱氧葡萄糖摄取的正常化。此外，乙醇还扰乱了微管动态，这延迟了去除微管破坏剂诺考达唑后正常微管组织的恢复。同样，用LPA预处理可防止这种改变。持续表达活化Rho突变蛋白（GTP结合形式）的经乙醇处理的啮齿动物成纤维细胞NIH3T3对乙醇不敏感，因为它们在肌动蛋白应力纤维组织或2-脱氧葡萄糖摄取方面均未出现改变。我们讨论了乙醇可能改变细胞骨架和己糖摄取的假定信号转导靶点以及LPA对乙醇诱导损伤的细胞保护作用。后者开启了一种可能性，即LPA或类似的不可水解脂质衍生物可作为针对乙醇有害影响的细胞保护剂。
