title: Visualizing spatial lipid distribution in porcine lens by MALDI imaging high-resolution mass spectrometry.
abstract: 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.
authors.affiliation: Laboratory of Molecular Structure Characterization, Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: Veronika
authors.initials: V
authors.lastname: Vidová
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Pól
authors.forename: Michael
authors.initials: M
authors.lastname: Volny
authors.forename: Petr
authors.initials: P
authors.lastname: Novák
authors.forename: Vladimír
authors.initials: V
authors.lastname: Havlícek
authors.forename: Susanne K
authors.initials: SK
authors.lastname: Wiedmer
authors.forename: Juha M
authors.initials: JM
authors.lastname: Holopainen
mesh_terms: D053000:Analytic Sample Preparation Methods; D000818:Animals; D005583:Fourier Analysis; D007908:Lens, Crystalline / Q000378:metabolism*; D050356:Lipid Metabolism; D057054:Molecular Imaging / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013107:Sphingolipids / Q000378:metabolism; D013552:Swine
chemical_list: D013107:Sphingolipids
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