title: MALDI-MS-imaging of whole human lens capsule.
abstract: The ocular lens capsule is a smooth, transparent basement membrane that encapsulates the lens and is composed of a rigid network of interacting structural proteins and glycosaminoglycans. During cataract surgery, the anterior lens capsule is routinely removed in the form of a circular disk. We considered that the excised capsule could be easily prepared for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry imaging (MALDI-MSI) analysis. MALDI-MSI is a powerful tool to elucidate the spatial distribution of small molecules, peptides, and proteins within tissues. Here, we apply this molecular imaging technique to analyze the freshly excised human lens capsule en face. We demonstrate that novel information about the distribution of proteins by MALDI-MSI can be obtained from this highly compact connective tissue, having no evident histo-morphological characteristics. Trypsin digestion carried out on-tissue is shown to improve MALDI-MSI analysis of human lens capsules and affords high repeatability. Most importantly, MALDI-MSI analysis reveals a concentric distribution pattern of proteins such as apolipoprotein E (ApoE) and collagen IV alpha-1 on the anterior surface of surgically removed lens capsule, which may indicate direct or indirect effects of environmental and mechanical stresses on the human ocular lens.
authors.affiliation: School of Chemical and Physical Sciences, Flinders University, Bedford Park SA 5042, Australia. maurizio.ronci@flinders.edu.au
authors.forename: Maurizio
authors.initials: M
authors.lastname: Ronci
authors.forename: Shiwani
authors.initials: S
authors.lastname: Sharma
authors.forename: Tim
authors.initials: T
authors.lastname: Chataway
authors.forename: Kathryn P
authors.initials: KP
authors.lastname: Burdon
authors.forename: Sarah
authors.initials: S
authors.lastname: Martin
authors.forename: Jamie E
authors.initials: JE
authors.lastname: Craig
authors.forename: Nicolas H
authors.initials: NH
authors.lastname: Voelcker
mesh_terms: D000595:Amino Acid Sequence; D001057:Apolipoproteins E / Q000378:metabolism; D024141:Collagen Type IV / Q000378:metabolism; D005136:Eye Proteins / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D007903:Lens Capsule, Crystalline / Q000378:metabolism*; D008969:Molecular Sequence Data; D015203:Reproducibility of Results; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D001057:Apolipoproteins E; D024141:Collagen Type IV; D005136:Eye Proteins