Department of Biology, Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pashan, Pune, Maharashtra 411008, India.
Biochemistry. 2024 Sep 17;63(18):2300-2309. doi: 10.1021/acs.biochem.4c00160. Epub 2024 Jul 10.
Cholesterol is central to mammalian lipid metabolism and serves many critical functions in the regulation of diverse physiological processes. Dysregulation in cholesterol metabolism is causally linked to numerous human diseases, and therefore, in vivo, the concentrations and flux of cholesterol and cholesteryl esters (fatty acid esters of cholesterol) are tightly regulated. While mass spectrometry has been an analytical method of choice for detecting cholesterol and cholesteryl esters in biological samples, the hydrophobicity, chemically inert nature, and poor ionization of these neutral lipids have often proved a challenge in developing lipidomics compatible liquid chromatography-mass spectrometry (LC-MS) methods to study them. To overcome this problem, here, we report a reverse-phase LC-MS method that is compatible with existing high-throughput lipidomics strategies and capable of identifying and quantifying cholesterol and cholesteryl esters from mammalian cells and tissues. Using this sensitive yet robust LC-MS method, we profiled different mammalian cell lines and tissues and provide a comprehensive picture of cholesterol and cholesteryl esters content in them. Specifically, among cholesteryl esters, we find that mammalian cells and tissues largely possess monounsaturated and polyunsaturated variants. Taken together, our lipidomics compatible LC-MS method to study this lipid class opens new avenues in understanding systemic and tissue-level cholesterol metabolism under various physiological conditions.
胆固醇是哺乳动物脂质代谢的核心，在调节多种生理过程中发挥着许多关键功能。胆固醇代谢失调与许多人类疾病有因果关系，因此，在体内，胆固醇和胆固醇酯（胆固醇的脂肪酸酯）的浓度和通量受到严格调节。尽管质谱分析一直是检测生物样本中胆固醇和胆固醇酯的首选分析方法，但这些中性脂质的疏水性、化学惰性和差的离子化特性常常给开发与脂质组学兼容的液相色谱-质谱联用 (LC-MS) 方法带来挑战，以研究它们。为了克服这个问题，在这里，我们报告了一种反相 LC-MS 方法，该方法与现有的高通量脂质组学策略兼容，能够从哺乳动物细胞和组织中鉴定和定量胆固醇和胆固醇酯。使用这种灵敏而稳健的 LC-MS 方法，我们对不同的哺乳动物细胞系和组织进行了分析，并提供了它们中胆固醇和胆固醇酯含量的全面图景。具体来说，在胆固醇酯中，我们发现哺乳动物细胞和组织主要含有单不饱和和多不饱和变体。总之，我们用于研究该脂质类别的与脂质组学兼容的 LC-MS 方法为在各种生理条件下理解系统和组织水平的胆固醇代谢开辟了新的途径。
