Linking Mass Spectrometric Imaging and Traditional Peptidomics: A Validation in the Obese Mouse Model

• Published in: Analytical chemistry (Washington) Vol. 83; no. 20; pp. 7682 - 7691
• Main Authors: Minerva, L, Boonen, K, Menschaert, G, Landuyt, B, Baggerman, G, Arckens, L
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 15-10-2011
• Subjects: Amino Acid Sequence; Analytical chemistry; Animals; Chemistry; Chromatographic methods and physical methods associated with chromatography; Chromatography; Chromatography, High Pressure Liquid; Cluster Analysis; Disease Models, Animal; Exact sciences and technology; Fourier Analysis; Identification; Mass spectrometry; Mice; Mice, Obese; Molecular Sequence Data; Other chromatographic methods; Pancreas - metabolism; Pancreas - pathology; Peptides; Peptides - analysis; Proteomics - methods; Spectrometric and optical methods; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization - instrumentation; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization - standards; Tissues; Animal model; Fourier transform spectroscopy; Peptides; Coupled method; Rodentia; Liquid chromatography; Identification; Matrix assisted laser desorption ionization; Tissue; Vertebrata; Mammalia; Mouse; Imaging; Mass spectrometry MS/MS; Peak; Large scale; Mass spectrometry; Quantitative analysis
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac200888j

MALDI mass spectrometry imaging (MSI) is a promising technique in the field of molecular (immuno)histology but is confronted with the problematic large-scale identification of peptides from thin tissue sections. In this study we present a workflow that significantly increased the number of identified peptides in a given MALDI-MSI data set and we evaluated its power concerning relative peptide quantifications. Fourier transform mass spectrometry (FTMS) profiling on matrix-coated thin tissue sections allowed us to align spectra of different MS sources, matching identical peaks in the process, thus linking MSI data to tandem mass spectrometry (MS/MS) on one hand and semiquantitative liquid chromatography (LC)/MS data on the other. Bonanza clustering was applied in order to group MS/MS spectra of structurally related peptides, making it possible to infer the identity of MSI-detected compounds based on identified members within the same cluster, effectively increasing the number of identifications in a single MSI data set. Out of 136 detected peptides with MALDI-MSI, we were able to identify 46 peptides. For 31 of these, a LC/quadrupole time-of-flight (QTOF) counterpart was detected, and we observed similar obese (ob/ob) to wild-type (wt) peak intensity ratios for 18 peptides. This workflow significantly increased the number of identifications of peptide masses detected with MALDI-MSI and evaluated the power of this imaging method for relative quantification of peptide levels between experimental conditions.