Mary L Kraft oral presentation (OB3-Tue3-1-3)
Imaging Cholesterol and Sphingolipids Within Cells
1 Dept of Chemical & Biomolecular Engr - University of Illinois, 600 S Mathews Ave, IL 61822 Urbana, United States
2 Glenn T. Seaborg Institute - Lawrence Livermore National Laboratory, 7000 East Ave., CA 94551 Livermore, United States
Lipids and cholesterol form the selectively permeable barriers that compartmentalize cellular processes. These biomolecules also play roles in other important biological processes, including signal transduction and intracellular transport. The relative distributions of cholesterol and various lipid species between organelles, which are membrane-bound compartments within eukaryotic cells, appears to be correlated with health and disease. For example, abnormal elevations in the cholesterol or glycosphingolipid abundances within endosomes appear to disrupt intracellular trafficking, and are hallmarks of lipid storage diseases . Yet, the biological mechanisms that regulate subcellular lipid abundance and their roles in health and disease are not well understood. As a first step in better understanding the regulation of subcellular lipid distribution, we have used of high-resolution SIMS, performed with a Cameca NanoSIMS 50, to image the distributions of cholesterol and a specific lipid class, called sphingolipids, within mammalian cells . To permit visualization, we metabolically incorporated distinct stable isotopes into the cholesterol and sphingolipids within living Madin-Darby Canine Kidney (MDCK) cells. Then we fixed the cells and used depth profiling SIMS to image the isotope-labeled cholesterol and sphingolipids within the cell. Three-dimensional representations revealed the isotope-labeled cholesterol and sphingolipids are enriched within separate intracellular compartments.
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