Department of Pharmacology, University of Colorado Denver, Aurora, CO 80045; and.
J Lipid Res. 2014 Mar;55(3):504-15. doi: 10.1194/jlr.M044990. Epub 2013 Dec 23.
MALDI imaging mass spectrometry (IMS) was used to characterize lipid species within sections of human eyes. Common phospholipids that are abundant in most tissues were not highly localized and observed throughout the accessory tissue, optic nerve, and retina. Triacylglycerols were highly localized in accessory tissue, whereas sulfatide and plasmalogen glycerophosphoethanolamine (PE) lipids with a monounsaturated fatty acid were found enriched in the optic nerve. Additionally, several lipids were associated solely with the inner retina, photoreceptors, or retinal pigment epithelium (RPE); a plasmalogen PE lipid containing DHA (22:6), PE(P-18:0/22:6), was present exclusively in the inner retina, and DHA-containing glycerophosphatidylcholine (PC) and PE lipids were found solely in photoreceptors. PC lipids containing very long chain (VLC)-PUFAs were detected in photoreceptors despite their low abundance in the retina. Ceramide lipids and the bis-retinoid, N-retinylidene-N-retinylethanolamine, was tentatively identified and found only in the RPE. This MALDI IMS study readily revealed the location of many lipids that have been associated with degenerative retinal diseases. Complex lipid localization within retinal tissue provides a global view of lipid organization and initial evidence for specific functions in localized regions, offering opportunities to assess their significance in retinal diseases, such as macular degeneration, where lipids have been implicated in the disease process.
基质辅助激光解吸电离成像质谱(MALDI IMS)用于对人眼切片中的脂质种类进行特征分析。在视神经和视网膜中,丰富存在于大多数组织中的常见磷脂并未高度定位,而是分布于整个附属组织中。三酰甘油高度定位于附属组织,而带有单不饱和脂肪酸的硫酸脑苷脂和醚磷脂甘油磷酸乙醇胺(PE)脂质则在视神经中富集。此外,有几种脂质仅与内视网膜、光感受器或视网膜色素上皮(RPE)有关;一种含有二十二碳六烯酸(22:6)的醚型 PE 脂质(PE(P-18:0/22:6))仅存在于内视网膜中,而仅在光感受器中发现含有二十二碳六烯酸的甘油磷脂酰胆碱(PC)和 PE 脂质。尽管在视网膜中含量较低,但仍在光感受器中检测到含有超长链(VLC)-PUFA 的 PC 脂质。神经酰胺脂质和双视黄醇,N-视黄醛-N-视黄醇乙胺,被初步鉴定并仅在 RPE 中发现。这项 MALDI IMS 研究清楚地揭示了许多与退行性视网膜疾病相关的脂质的位置。视网膜组织中复杂的脂质定位提供了脂质组织的全局视图,并为局部区域的特定功能提供了初步证据,为评估它们在视网膜疾病(如黄斑变性)中的意义提供了机会,因为脂质已被认为与疾病过程有关。