DaeWon Moon oral presentation (OB3-Thu3-1-4)
Multiplex SIMS imaging of Proteins and Proximity Analysis of Hippocampal Tissues from Aged and Alzheimer Disease Mouse
DGIST, TechnoJungAngDaeRo 333, 711-873 Daegu, Korea, Republic of
With the development of gas cluster ion beam technology, which is a great step forward to biomedical imaging, SIMS still has technical barriers to overcome to be accepted as one of powerful biomedicla imagign tools. The most critical problem in biological SIMS imaging would be the lack of protein and peptide imaging of cells and tissues, since most of biological story telling are mainly based on proteins and their interactions. We have developed a new multiplex protein imaging method for TOF-SIMS with metal oxide nanoparticle (MONP) conjugated with proteins up to 9 proteins.
In SIMS analysis, MONPs provide high secondary ionization yield and amplification of ion yields. We systhesized 9 MONPs working right such as CoO, CdO, Fe3O4, TiO2, PbO, In2O3, SiO2, Al2O3, La2O3. In addition to protein imaging, SIMS intrinsically provides tens of bio-molecular imaging including lipids and metabolites, and metals with a TOF mass analyzer, which makes this new methodology to be an omni-molecular mass spectrometric imaging technique. Sliced and cultured mouse hippocampal tissues were imaged with typical spatial resolution of 2 µm, which can be improved down to 300 nm for 9 neuronal proteins with tens of lipids including cholesterol, fatty acids, glycerophospholipids, several neurotransmitters, and a couple of metals simultaneously. Lipid SIMS imaging was obtained from the surface without sputtering, since the lipid intensity is high at the surface probably due to the surface segregation of lipids but protein SIMS imaging was accumulated over 3 µm with Ar gas cluster ion. Proteins chosen to image mouse hippocampal tissues are NeuN for all nuclei, Cav1,3 for neuron cells, Iba1 for microglia cells, GFAP for astrocytes, AMPA receptor, phosphorylated Tau, amyloid beta (Aß) 1-42, amyloid precursor protein, and APOE, which were selected to visualize important proteins as landmarks of Alzheimer Disease (AD).
Omni-molecular mass spectrometric SIMS imaging was applied to mouse hippocampal tissues from 3 months young control mouse, 3 months young AD mouse, 7-13 months old control mouse, and 7-13 months old AD mouse. Imaging was focused to CA1 region of hippocampus, since the change in the region is most significant with AD. Changes in neuron cells, microglial cells, astrocytes, AMPA receptors, Aß, phosphorylated Tau, APOE, and lipids such as cholesterol, MAG, DAG, and fatty acids were observed and discussed. With the multiplex protein imaging, we estimated the proximity of proteins in hippocampal tissues.
With the development of multiplex protein SIMS imaging technology, I expect bio-SIMS to be routinely used in the biomedical community as omni-molecular mass spectrometric imaging as dynamic SIMS in the semiconductor industrial community.