Kirkland J B, Bray T M, Bettger W J
Department of Nutritional Sciences, College of Biological Science, University of Guelph, Ont., Canada.
Can J Physiol Pharmacol. 1987 Aug;65(8):1788-92. doi: 10.1139/y87-278.
The present study was designed to test the hypothesis that a pneumotoxin, 3-methylindole, alters the basic metabolic pathways involved in phospholipid and neutral lipid synthesis in cultured fibroblasts. Rat skin fibroblasts were obtained from day-old pups. Confluent monolayers were preincubated for up to 24 h with a range of concentrations (0-0.76 mM) of 3-methylindole. Following these treatments, the cell lipids were labelled by incubation for 6 h with [14C]glycerol. The lipids were extracted, separated by thin layer chromatography, and the radioactivity in each fraction was determined. 3-Methylindole had no effect on the total incorporation of [14C]glycerol into lipids, but significantly altered the distribution among lipid fractions. Incubation with 3-methylindole caused a decrease in the incorporation of [14C]glycerol into phosphatidylcholine, while radioactivity accumulated in the neutral lipid fraction. The other lipid fractions responded variably. Similarily, Flow 2000 human diploid lung fibroblasts were incubated for 24 h with 3-methylindole followed by treatment with [14C]glycerol, resulting in a 74% decrease in the incorporation of [14C]glycerol into phosphatidylcholine and a 50% increase in its accumulation in neutral lipid. The results indicate that 3-methylindole inhibits the synthesis of phosphatidylcholine from diacylglycerol precursors on the endoplasmic reticulum in cultured fibroblasts. This is an important observation as it shows that 3-methylindole affects the synthesis of phospholipids required for membrane turnover in cells that are not specialized for the production of phospholipids for surfactant.
本研究旨在验证一种肺毒素3-甲基吲哚会改变培养的成纤维细胞中参与磷脂和中性脂质合成的基本代谢途径这一假设。从新生幼鼠获取大鼠皮肤成纤维细胞。将汇合的单层细胞用一系列浓度（0 - 0.76 mM）的3-甲基吲哚预孵育长达24小时。经过这些处理后，通过用[¹⁴C]甘油孵育6小时对细胞脂质进行标记。提取脂质，通过薄层色谱法进行分离，并测定每个组分中的放射性。3-甲基吲哚对[¹⁴C]甘油掺入脂质的总量没有影响，但显著改变了脂质组分之间的分布。用3-甲基吲哚孵育导致[¹⁴C]甘油掺入磷脂酰胆碱的量减少，而放射性在中性脂质组分中积累。其他脂质组分的反应各不相同。同样，将Flow 2000人二倍体肺成纤维细胞用3-甲基吲哚孵育24小时，然后用[¹⁴C]甘油处理，导致[¹⁴C]甘油掺入磷脂酰胆碱的量减少74%，其在中性脂质中的积累增加50%。结果表明，3-甲基吲哚抑制培养的成纤维细胞内质网上二酰基甘油前体合成磷脂酰胆碱。这是一项重要的观察结果，因为它表明3-甲基吲哚会影响那些并非专门用于产生表面活性剂磷脂的细胞中膜更新所需磷脂的合成。
