title: A method to prevent protein delocalization in imaging mass spectrometry of non-adherent tissues: application to small vertebrate lens imaging.
abstract: MALDI imaging requires careful sample preparation to obtain reliable, high-quality images of small molecules, peptides, lipids, and proteins across tissue sections. Poor crystal formation, delocalization of analytes, and inadequate tissue adherence can affect the quality, reliability, and spatial resolution of MALDI images. We report a comparison of tissue mounting and washing methods that resulted in an optimized method using conductive carbon substrates that avoids thaw mounting or washing steps, minimizes protein delocalization, and prevents tissue detachment from the target surface. Application of this method to image ocular lens proteins of small vertebrate eyes demonstrates the improved methodology for imaging abundant crystallin protein products. This method was demonstrated for tissue sections from rat, mouse, and zebrafish lenses resulting in good-quality MALDI images with little to no delocalization. The images indicate, for the first time in mouse and zebrafish, discrete localization of crystallin protein degradation products resulting in concentric rings of distinct protein contents that may be responsible for the refractive index gradient of vertebrate lenses.
authors: Department of Biochemistry, Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, TN, 37205-0146, USA.
authors: David M G
authors: DM
authors: Anderson
authors: Kyle A
authors: KA
authors: Floyd
authors: Stephen
authors: S
authors: Barnes
authors: Judy M
authors: JM
authors: Clark
authors: John I
authors: JI
authors: Clark
authors: Hassane
authors: H
authors: Mchaourab
authors: Kevin L
authors: KL
authors: Schey
mesh_terms: D053000:Analytic Sample Preparation Methods / Q000379:methods*; D000818:Animals; D003459:Crystallins / Q000737:chemistry / Q000378:metabolism*; D005260:Female; D007908:Lens, Crystalline / Q000737:chemistry / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008813:Mice, Inbred ICR; D057054:Molecular Imaging; D021381:Protein Transport; D051381:Rats; D017208:Rats, Wistar; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D015027:Zebrafish
chemical_list: D003459:Crystallins