Laboratory of Molecular Structure Characterization, Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
J Lipid Res. 2010 Aug;51(8):2295-302. doi: 10.1194/jlr.M005488. Epub 2010 Apr 13.
The intraocular lens contains high levels of both cholesterol and sphingolipids, which are believed to be functionally important for normal lens physiology. The aim of this study was to explore the spatial distribution of sphingolipids in the ocular lens using mass spectrometry imaging (MSI). Matrix-assisted laser desorption/ionization (MALDI) imaging with ultra high resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was used to visualize the lipid spatial distribution. Equatorially-cryosectioned, 12 microm thick slices of tissue were thaw-mounted to an indium-tin oxide (ITO) glass slide by soft-landing to an ethanol layer. This procedure maintained the tissue integrity. After the automated MALDI matrix deposition, the entire lens section was examined by MALDI MSI in a 150 microm raster. We obtained spatial- and concentration-dependent distributions of seven lens sphingomyelins (SM) and two ceramide-1-phosphates (CerP), which are important lipid second messengers. Glycosylated sphingolipids or sphingolipid breakdown products were not observed. Owing to ultra high resolution MS, all lipids were identified with high confidence, and distinct distribution patterns for each of them are presented. The distribution patterns of SMs provide an understanding of the physiological functioning of these lipids in clear lenses and offer a novel pathophysiological means for understanding diseases of the lens.
晶状体中含有高水平的胆固醇和神经鞘脂,这些物质被认为对正常晶状体生理功能具有重要作用。本研究旨在利用质谱成像(MSI)技术探索神经鞘脂在眼部晶状体中的空间分布。采用基质辅助激光解吸/电离(MALDI)成像联合超高分辨率傅里叶变换离子回旋共振质谱(FT-ICR MS)对脂质的空间分布进行可视化研究。通过软着陆到乙醇层,将赤道区冷冻切片、厚度为 12 微米的组织切片解冻并贴附到铟锡氧化物(ITO)玻璃载玻片上。此过程可以维持组织的完整性。在自动 MALDI 基质沉积后,通过 MALDI MSI 在 150 微米的栅格中对整个晶状体切片进行检查。我们获得了 7 种晶状体神经鞘磷脂(SM)和 2 种神经酰胺-1-磷酸(CerP)的空间和浓度依赖性分布,这些物质是重要的脂质第二信使。未观察到糖基化神经鞘脂或神经鞘脂分解产物。由于超高分辨率 MS,所有脂质的鉴定都具有高度的可信度,并且呈现出它们各自独特的分布模式。SM 的分布模式为了解这些脂质在透明晶状体中的生理功能提供了依据,并为理解晶状体疾病的病理生理学提供了新的方法。