Secondary‐Ion Mass Spectrometry Images Cardiolipins and Phosphatidylethanolamines at the Subcellular Level

Abstract

Millions of diverse molecules constituting the lipidome act as important signals within cells. Of these, cardiolipin (CL) and phosphatidylethanolamine (PE) participate in apoptosis and ferroptosis, respectively. Their subcellular distribution is largely unknown. Imaging mass spectrometry is capable of deciphering the spatial distribution of multiple lipids at subcellular levels. Here we report the development of a unique 70 keV gas‐cluster ion beam that consists of (CO2)n+(n>10 000) projectiles. Coupled with direct current beam buncher‐time‐of‐flight secondary‐ion mass spectrometry, it is optimized for sensitivity towards high‐mass species (up to m/z 3000) at high spatial resolution (1 μm). In combination with immunohistochemistry, phospholipids, including PE and CL, have been assessed in subcellular compartments of mouse hippocampal neuronal cells and rat brain tissue.

Achieving Life through Death: Redox Biology of Lipid Peroxidation in Ferroptosis

“…However, this does not take into consideration the other key components of the ferroptotic program: 15-LOX and GSH. Notably, contemporary MS imaging, particularly the protocol of secondary ion MS utilizing gas cluster ion beams (Tian et al, 2019), detects AA-PE species in different subcellular localizations of brain cells (e.g., neurons, astrocytes) (Figure S3), thus offering remarkable opportunities for identifying the major sites of catalytic initiation of the ferroptotic process.…”

Correlated fluorescence microscopy and multi-ion beam secondary ion mass spectrometry imaging reveals phosphatidylethanolamine increases in the membrane of cancer cells over-expressing the molecular chaperone subunit CCTδ

“…While the implementation of GCIBs for SIMS analysis has greatly improved the sensitivity of the technique to intact biomolecules, in this study, univariate analysis of the different signals was not sufficient to identify chemical changes in the transfected cells while multivariate analysis and imaging of multiple correlated peaks showed discrimination within the cellular populations based on phenotype. Further improvements to the analytical workflow may include perform the analysis on frozen hydrated samples, possibly with the implementation of water cluster ion beams that can further increase intact lipid signals, notably PEs, from single cells [ 31 ].…”

Chemical Analysis of Single Cells and Organelles

“…Winograd and co-workers recently presented the development of a unique version of high-voltage CO 2 GCIB. 139 In short, the beam reportedly lead to an unprecedented spatial resolution of 1–1.6 μm for intact lipid imaging at the cellular and subcellular level in single HT22 cells (hippocampal neuronal cell line) using a direct current beam buncher-ToF-SIMS ( Figure 8 A). Further analyses (e.g., immunohistochemistry and depth profiling) were performed and were described to further characterize beam performance and sample features.…”

“…2019 , 58 , 3156–3161. Copyright 2019 Angewandte Chemie (ref ( 139 )). (B) 12 C 14 N – , 12 C 2 – , and 28 Si – secondary ion count rates and δ 13 C VPDB vs Cs + ion dose.…”