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.

Laboratory of Molecular Structure Characterization Institute of Microbiology Academy of Sciences of the Czech Republic Prague Czech Republic

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Han J., Schey K. L. 2006. MALDI tissue Imaging of ocular lens alpha-crystallin. Invest. Ophthalmol. Vis. Sci. 47: 2990–2996. PubMed

Caprioli R. M., Farmer T. B., Gile J. 1997. Molecular imaging of biological samples: Localization of peptides and proteins using MALDI-TOF MS. Anal. Chem. 69: 4751–4760. PubMed

Chaurand P., Norris J. L., Cornett D. S., Mobley J. A., Caprioli R. M. 2006. New developments in profiling and imaging of proteins from tissue sections by MALDI mass spectrometry. J. Proteome Res. 5: 2889–2900. PubMed

Börner K., Malmberg P., Månsson J-E., Nygren H. 2007. Molecular imaging of lipids in cells and tissues. Int. J. Mass Spectrom. 260: 128–136.

Amaya K. R., Monroe E. B., Sweedler J. V., Clayton D. F. 2007. Lipid imaging in the zebra finch brain with secondary ion mass spectrometry. Int. J. Mass Spectrom. 260: 121–127.

Murphy R. C., Hankin J. A., Barkley R. M. 2009. Imaging of lipid species by MALDI mass spectrometry. J. Lipid Res. 50: S317–S322. PubMed PMC

Pól J., Vidová V., Kruppa G., Kobliha V., Novák P., Lemr K., Kotiaho T., Kostiainen R., Havlíček V., Volný M. 2009. Automated ambient desorption-ionization platform for surface imaging integrated with a commercial Fourier transform ion cyclotron resonance mass spectrometer. Anal. Chem. 81: 8479–8487. PubMed

Wiseman J. M., Ifa D. R., Song Q. Y., Cooks R. G. 2006. Tissue imaging at atmospheric pressure using desorption electrospray ionization (DESI) mass spectrometry. Angew. Chem. Int. Ed. Engl. 45: 7188–7192. PubMed

Dill A. L., Ifa D. R., Manicke N. E., Zheng O. Y., Cooks R. G. 2009. Mass spectrometric imaging of lipids using desorption electrospray ionization. J. Chromatogr. B Analyt. Technol. Biomed. Life Sci. 877: 2883–2889. PubMed PMC

Grey A. C., Schey K. L. 2009. Age-related changes in the spatial distribution of human lens alpha-crystallin products by MALDI imaging mass spectrometry. Invest. Ophthalmol. Vis. Sci. 50: 4319–4329. PubMed PMC

Grey A. C., Chaurand P., Caprioli R. M., Schey K. L. 2009. MALDI imaging mass spectrometry of integral membrane proteins from ocular lens and retinal tissue. J. Proteome Res. 8: 3278–3283. PubMed PMC

Grey A. C., Schey K. L. 2008. Distribution of bovine and rabbit lens alpha-crystallin products by MALDI imaging mass spectrometry. Mol. Vis. 14: 171–179. PubMed PMC

Rujoi M., Estrada R., Yappert M. C. 2004. In situ MALDI-TOF MS regional analysis of neutral phospholipids in lens tissue. Anal. Chem. 76: 1657–1663. PubMed

Byrdwell W. C., Borchman D., Porter R. A., Taylor K. G., Yappert M. C. 1994. Separation and characterization of the unknown phospholipid in human lens membranes. Invest. Ophthalmol. Vis. Sci. 35: 4333–4343. PubMed

Borchman D., Delamere N., McCauley L., Paterson C. 1989. Studies on the distribution of cholesterol, phospholipid, and protein in the human and bovine lens. Lens Eye Toxic. Res. 6: 703–724. PubMed

Sane P., Tuomisto F., Wiedmer S. K., Nyman T., Vattulainen I., Holopainen J. M. 2010. Temperature-induced structural transition in-situ in porcine lens—changes observed in void size distribution. Biochim. Biophys. Acta. 1798: 958–65. PubMed

Holopainen J. M., Metso A. J., Mattila J. P., Jutila A., Kinnunen P. K. J. 2004. Evidence for the lack of a specific interaction between cholesterol and sphingomyelin. Biophys. J. 86: 1510–1520. PubMed PMC

Lipid Maps. Nature Publishing Group and LIPID MAPS Consortium. Available from: http://www.lipidmaps.org.

Rasband W. S., Image J. 1997–2009. U. S. National Institutes of Health. Available from: http://rsb.info.nih.gov/ij/.

Estrada R., Yappert M. C. 2004. Regional phospholipid analysis of porcine lens membranes by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. J. Mass Spectrom. 39: 1531–1540. PubMed

Altelaar A. F. M., van Minnen J., Jimenez C. R., Heeren R. M. A., Piersma S. R. 2005. Direct molecular imaging of Lymnaea stagnalis nervous tissue at subcellular spatial resolution by mass spectrometry. Anal. Chem. 77: 735–741. PubMed

Nygren H., Malmberg P., Kriegeskotte C., Arlinghaus H. F. 2004. Bioimaging TOF-SIMS: localization of cholesterol in rat kidney sections. FEBS Lett. 566: 291–293. PubMed

Wu C., Ifa D. R., Manicke N. E., Cooks R. G. 2009. Rapid, direct analysis of cholesterol by charge labeling in reactive desorption electrospray ionization. Anal. Chem. 81: 7618–7624. PubMed PMC

Yappert M. C., Rujoi M., Borchman D., Vorobyov I., Estrada R. 2003. Glycero-versus sphingo-phospholipids: correlations with human and non-human mammalian lens growth. Exp. Eye Res. 76: 725–734. PubMed

Burnum K. E., Cornett D. S., Puolitaival S. M., Milne S. B., Myers D. S., Tranguch S., Brown H. A., Dey S. K., Caprioli R. M. 2009. Spatial and temporal alterations of phospholipids determined by mass spectrometry during mouse embryo implantation. J. Lipid Res. 50: 2290–2298. PubMed PMC

Byrdwell W. C. 1998. Dual parallel mass spectrometers for analysis of sphingolipid, glycerophospholipid and plasmalogen molecular species. Rapid Commun. Mass Spectrom. 12: 256–272. PubMed

Iwata J. L., Bardygulanonn L. G., Greiner J. V. 1995. Interspecies comparisons of lens phospholipids. Curr. Eye Res. 14: 937–941. PubMed

Greiner J. V., Auerbach D. B., Leahy C. D., Glonek T. 1994. Distribution of membrane phospholipids in the crystalline lens. Invest. Ophthalmol. Vis. Sci. 35: 3739–3746. PubMed

Kinoshita J. H. 1974. Mechanisms initiating cataract formation (Proctor Lecture). Invest. Ophthalmol. Vis. Sci. 13: 713–724. PubMed

Li L. K., So L., Spector A. 1987. Age-dependent changes in the distribution and concentration of human lens cholesterol and phospholipids. Biochim. Biophys. Acta. 917: 112–120. PubMed

Li L. K., So L., Spector A. 1985. Membrane cholesterol and phospholipid in consecutive concentric sections of human lenses. J. Lipid Res. 26: 600–609. PubMed

Estrada R., Puppato A., Borchman D., Yappert M. C. 2010. Reevaluation of the phospholipid composition in membranes of adult human lenses by 31P NMR and MALDI MS. Biochim. Biophys. Acta. 1798: 303–311. PubMed

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