Mai Thuy Hoang oral presentation (OB3-Wed2-1-5)
ToF-SIMS imaging of deuterated omega-3 and omega-6 fatty acids and their conversion products incorporated in cell membrane
1 Department of Chemical and Chemical Engineering, Chalmers University of Technology, Gothenburg, Maskingränd 2, 41296 Goteborg, Sweden
2 National Center Imaging Mass Spectrometry, Gothenburg, Maskingränd 2, 41296 Goteborg, Sweden
3 Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Maskingränd 2, 41296 Goteborg, Sweden
The synthesis of phospholipids in mammalian cells is regulated by the main source, phosphatidic acid, which contains polyunsaturated fatty acids. Polyunsaturated fatty acids, especially omega-3 and -6 polyunsaturated fatty acids is known to be important for the development and function of the human brain. α-linolenic acid (ω3) and linoleic acid (ω6) have been demonstrated as the precursor for synthesis of long chain polyunsaturated fatty acids and functions as a resource for lipid synthesis. Several reports showed an increase in the total phospholipid content after incubating omega-3 and -6 fatty acids in rats and cells. However, the specific phospholipids in which the fatty acids are incorporated into remain unknown. Therefore, we examined the incorporation of deuterium-isotopic α-linolenic acid (ω3) and linoleic acid (ω6) into phospholipids in the plasma membrane of PC12 cells using time of flight secondary ion mass spectrometry (TOF-SIMS). Two types of ToF-SIMS instruments have been used to obtain the chemical localization in cells: a TOF-SIMS V equipped with a 25keV Bismuth liquid metal ion gun (LMIG) and a J105 ToF-SIMS equipped with a 40keV CO2 gas cluster ion beam (GCIB). The LMIG with high spatial resolution allowed for deuterium detection at the nanoscale while high mass resolution intact phospholipid detection could be achieved using GCIB as a primary ion source. The combination of the two instruments gave us more information in a wide mass range with high mass resolution. Our data showed the increase in contents of fatty acids and phospholipids in the plasma membrane. Isotope tracer studies also indicated the incorporation of deuterated fatty acids into unsaturated diacylglycerols, phosphatidylcholines, phosphatidylethanolamines, and phosphatidylinositols.