Imaging of human lens lipids by desorption electrospray ionization mass spectrometry

Journal Article


Abstract


  • The lipid composition of the human lens is distinct from most other tissues in that it is high in dihydrosphingomyelin and the most abundant glycerophospholipids in the lens are unusual 1-O-alkyl-ether linked phosphatidylethanolamines and phosphatidylserines. In this study, desorption electrospray ionization (DESI) mass spectrometry-imaging was used to determine the distribution of these lipids in the human lens along with other lipids including, ceramides, ceramide-1-phosphates and lyso 1-O-alkyl ethers. To achieve this 25 μm lens slices were mounted onto glass slides and analyzed using a linear ion-trap mass spectrometer equipped with a custom-built, 2-D automated DESI source. In contrast to other tissues that have been previously analyzed by DESI, the presence of a strong acid in the spray solvent was required to desorb lipids directly from lens tissue. Distinctive distributions were observed for [M+H]+ ions arising from each lipid class. Of particular interest were ionized 1-O-alkyl phosphatidylethanolamines and phosphatidylserines, PE (18:1e/18:1) and PS (18:1e/18:1), which were found in a thin ring in the outer-most region of the lens. This distribution was confirmed by quantitative analysis of lenses that were sectioned into four distinct regions (outer, barrier, inner and core), extracted and analyzed by electrospray ionization tandem mass spectrometry. DESI-imaging also revealed a complementary distribution for the structurally-related lyso 1-O-alkyl phosphatidylethanolamine, LPE (18:1e), which was localized closer to the centre of the lens. The data obtained in this study indicate that DESI-imaging is a powerful tool for determining the spatial distribution of human lens lipids.

Authors


  •   Ellis, Shane R. (external author)
  •   Wu, Chunping (external author)
  •   Deeley, Jane M. (external author)
  •   Zhu, Xiangjia (external author)
  •   Truscott, Roger J. W.
  •   in het Panhuis, Marc
  •   Cooks, R G. (external author)
  •   Mitchell, Todd
  •   Blanksby, Stephen J. (external author)

Publication Date


  • 2010

Citation


  • Ellis, S. R., Wu, C., Deeley, J. M., Zhu, X., Truscott, R. J.W., in het Panhuis, M., Cooks, R. G., Mitchell, T. W. & Blanksby, S. J. (2010). Imaging of human lens lipids by desorption electrospray ionization mass spectrometry. Journal of the American Society for Mass Spectrometry, 21 (12), 2095-2104.

Scopus Eid


  • 2-s2.0-78649529309

Ro Metadata Url


  • http://ro.uow.edu.au/scipapers/5098

Number Of Pages


  • 9

Start Page


  • 2095

End Page


  • 2104

Volume


  • 21

Issue


  • 12

Place Of Publication


  • http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6TH2-5120K3K-1-P&_cdi=5270&_user=202616&_pii=S1044030510005970&_origin=browse&_coverDate=12%2F31%2F2010&_sk=999789987&view=c&wchp=dGLzVtb-zSkWA&md5=0baf0412f2c5bfbf800c72b91609892e&ie=/sdarticle.pdf

Abstract


  • The lipid composition of the human lens is distinct from most other tissues in that it is high in dihydrosphingomyelin and the most abundant glycerophospholipids in the lens are unusual 1-O-alkyl-ether linked phosphatidylethanolamines and phosphatidylserines. In this study, desorption electrospray ionization (DESI) mass spectrometry-imaging was used to determine the distribution of these lipids in the human lens along with other lipids including, ceramides, ceramide-1-phosphates and lyso 1-O-alkyl ethers. To achieve this 25 μm lens slices were mounted onto glass slides and analyzed using a linear ion-trap mass spectrometer equipped with a custom-built, 2-D automated DESI source. In contrast to other tissues that have been previously analyzed by DESI, the presence of a strong acid in the spray solvent was required to desorb lipids directly from lens tissue. Distinctive distributions were observed for [M+H]+ ions arising from each lipid class. Of particular interest were ionized 1-O-alkyl phosphatidylethanolamines and phosphatidylserines, PE (18:1e/18:1) and PS (18:1e/18:1), which were found in a thin ring in the outer-most region of the lens. This distribution was confirmed by quantitative analysis of lenses that were sectioned into four distinct regions (outer, barrier, inner and core), extracted and analyzed by electrospray ionization tandem mass spectrometry. DESI-imaging also revealed a complementary distribution for the structurally-related lyso 1-O-alkyl phosphatidylethanolamine, LPE (18:1e), which was localized closer to the centre of the lens. The data obtained in this study indicate that DESI-imaging is a powerful tool for determining the spatial distribution of human lens lipids.

Authors


  •   Ellis, Shane R. (external author)
  •   Wu, Chunping (external author)
  •   Deeley, Jane M. (external author)
  •   Zhu, Xiangjia (external author)
  •   Truscott, Roger J. W.
  •   in het Panhuis, Marc
  •   Cooks, R G. (external author)
  •   Mitchell, Todd
  •   Blanksby, Stephen J. (external author)

Publication Date


  • 2010

Citation


  • Ellis, S. R., Wu, C., Deeley, J. M., Zhu, X., Truscott, R. J.W., in het Panhuis, M., Cooks, R. G., Mitchell, T. W. & Blanksby, S. J. (2010). Imaging of human lens lipids by desorption electrospray ionization mass spectrometry. Journal of the American Society for Mass Spectrometry, 21 (12), 2095-2104.

Scopus Eid


  • 2-s2.0-78649529309

Ro Metadata Url


  • http://ro.uow.edu.au/scipapers/5098

Number Of Pages


  • 9

Start Page


  • 2095

End Page


  • 2104

Volume


  • 21

Issue


  • 12

Place Of Publication


  • http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6TH2-5120K3K-1-P&_cdi=5270&_user=202616&_pii=S1044030510005970&_origin=browse&_coverDate=12%2F31%2F2010&_sk=999789987&view=c&wchp=dGLzVtb-zSkWA&md5=0baf0412f2c5bfbf800c72b91609892e&ie=/sdarticle.pdf