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The utilization of fluorescence to identify the components of lipofuscin by imaging mass spectrometry
Author(s) -
Ablonczy Zsolt,
Smith Noah,
Anderson David M.,
Grey Angus C.,
Spraggins Jeffrey,
Koutalos Yiannis,
Schey Kevin L.,
Crouch Rosalie K.
Publication year - 2014
Publication title -
proteomics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.26
H-Index - 167
eISSN - 1615-9861
pISSN - 1615-9853
DOI - 10.1002/pmic.201300406
Subject(s) - lipofuscin , retinal pigment epithelium , fluorescence , macular degeneration , abca4 , mass spectrometry , chemistry , computational biology , colocalization , fluorescence lifetime imaging microscopy , retinal , biology , pathology , biochemistry , microbiology and biotechnology , medicine , chromatography , ophthalmology , phenotype , physics , quantum mechanics , gene
Lipofuscin, an aging marker in the retinal pigment epithelium (RPE) associated with the development of age‐related macular degeneration, is primarily characterized by its fluorescence. The most abundant component of RPE lipofuscin is N ‐retinylidene‐ N ‐retinylethanolamine (A2E) but its exact composition is not known due to the complexity of the RPE extract. In this study, we utilized MALDI imaging to find potential molecules responsible for lipofuscin fluorescence in RPE tissue from Abca4 −/− , Sv129 , and C57Bl6 / J mice aged 2 and 6 months. To assert relationships, the individual images in the MALDI imaging datasets were correlated with lipofuscin fluorescence recorded from the same tissues following proper registration. Spatial correlation information, which is usually lost in bioanalytics, pinpointed a relatively small number of potential lipofuscin components. The comparison of four samples in each condition further limited the possibility of false positives and provided various new, age‐ and strain‐specific targets. Validating the usefulness of the fluorescence‐enhanced imaging strategy, many known adducts of A2E were identified in the short list of lipofuscin components. These results provided evidence that mass spectrometric imaging can be utilized as a tool to begin to identify the molecular substructure of clinically‐relevant diagnostic information.