不饱和脂肪酸作为视黄醇X受体天然配体的分离与表征

Isolation and characterization of unsaturated fatty acids as natural ligands for the retinoid-X receptor.

作者信息

Goldstein Jonathan T, Dobrzyn Agnieszka, Clagett-Dame Margaret, Pike J Wesley, DeLuca Hector F

机构信息

Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA.

出版信息

Arch Biochem Biophys. 2003 Dec 1;420(1):185-93. doi: 10.1016/j.abb.2003.09.034.

DOI:10.1016/j.abb.2003.09.034

PMID:14622989

Abstract

The retinoid-X receptor (RXR) is a ligand activated nuclear receptor that is the heterodimer partner for many class II nuclear receptors. Previously identified natural ligands for this receptor include 9-cis retinoic acid (9cRA), docosahexaenoic acid, and phytanic acid. Our studies were performed to determine if there are any unidentified, physiologically important RXR ligands. Agonists for RXR were purified from rat heart and testes lipid extracts with the use of a cell-based reporter assay to monitor RXR activation. Purified active fractions contained a variety of unsaturated fatty acids and components were quantified by gas-liquid chromatography of derivatized samples. The corresponding fatty acid standards elicited a similar response in the reporter cell assay. Competition binding analysis revealed that the active fatty acids compete with [3H]9cRA for binding to RXR. Non-esterified fatty acids were analyzed from lipid extracts of isolated heart and testes nuclei and endogenous concentrations were found to be within the range of their determined binding affinities. Our studies reveal tissue dependent profiles of RXR agonists and support the idea of unsaturated fatty acids as physiological ligands of RXR.

摘要

视黄酸X受体（RXR）是一种配体激活的核受体，是许多II类核受体的异二聚体伴侣。此前已鉴定出该受体的天然配体包括9-顺式视黄酸（9cRA）、二十二碳六烯酸和植烷酸。我们开展研究以确定是否存在尚未确定的、具有重要生理意义的RXR配体。利用基于细胞的报告基因检测来监测RXR激活，从大鼠心脏和睾丸脂质提取物中纯化RXR激动剂。纯化的活性组分含有多种不饱和脂肪酸，通过衍生化样品的气液色谱法定量分析各组分。相应的脂肪酸标准品在报告基因细胞检测中引发了类似的反应。竞争结合分析表明，活性脂肪酸与[3H]9cRA竞争结合RXR。分析分离的心脏和睾丸细胞核脂质提取物中的非酯化脂肪酸，发现内源性浓度在其确定的结合亲和力范围内。我们的研究揭示了RXR激动剂的组织依赖性特征，并支持不饱和脂肪酸作为RXR生理配体的观点。