Lum, J. S. | Search bioRxiv

bioRxiv2025

Subcellular mass spectrometry imaging of lipids and nucleotides using transmission geometry ambient laser desorption and plasma ionisation

Demand for mass spectrometry imaging (MSI) technologies offering subcellular resolution for tissues and cell imaging is rapidly increasing. To accomplish this, efficient analyte ionisation is essential, given the small amounts of material sample in each pixel. Herein, we describe an atmospheric pressure transmission-geometry matrix-assisted laser desorption source equipped with plasma ionisation. By utilising a novel pre-staining method for sample preparation lipid signal intensities were enhanced by an order of magnitude compared to conventional matrix-only methods, while serendipitously enabling imaging of numerous nucleotides. The system enables detection of up to 200 lipids and nucleotides in tissues at 1 {micro}m-pixel size while informative MSI data is still obtained down to 250 nm pixel size. The use of sub-micron pixels is shown to discern subcellular features through combinations with fluorescence microscopy. This method provides a powerful tool for cellular and sub-cellular imaging of small molecules from tissues and cells for spatial biology applications.

cell biology↗

bioRxiv2020

Identification of repurposable cytoprotective drugs for Vanishing White Matter Disease

Vanishing white matter disease (VWMD) is a rare leukodystrophy involving loss of function mutations of the guanine exchange factor eIF2B and typically presenting with juvenile onset. We aimed to identify repurposable FDA approved drugs in an in vitro drug screen using patient-derived fibroblasts and induced pluripotent stem cell (iPSC)-derived astrocytes. Dysregulated GADD34 and CHOP were identified in patient fibroblasts and iPSC-derived astrocytes under proteasomal stress conditions. A drug screen from a 2400 FDA approved drug library with EIF2B5 disease patient fibroblasts identified 113 anti-inflammatory drugs as a major class of hits with cytoprotective effects. A panel of potential candidate drugs including berberine, deflazacort, ursodiol, zileuton, guanabenz and Anavex 2-73, and preclinical ISRIB, increased cell survival of MG132-stressed EIF2B2 and EIF2B5 disease VWMD astrocytes, and were further investigated for their effect on the integrated stress response and mitochondrial stress. ISRIB but not other drugs significantly affected eIF2 phosphorylation and GADD34 expression. Ursodiol demonstrated capacity to reduce complex I subunit upregulation, ameliorate oxidative stress, loss of mitochondrial membrane potential and upregulation of eIF2B subunits in VWMD astrocytes, highlighting its potential as a cytoprotective compound for VWMD.

neuroscience↗