Single-cell lipidomics with high structural specificity by mass spectrometry

Abstract

Single-cell analysis is critical to revealing cell-to-cell heterogeneity that would otherwise be lost in ensemble analysis. Detailed lipidome characterization for single cells is still far from mature, especially when considering the highly complex structural diversity of lipids and the limited sample amounts available from a single cell. We report the development of a general strategy enabling single-cell lipidomic analysis with high structural specificity. Cell fixation is applied to retain lipids in the cell during batch treatments prior to single-cell analysis. In addition to tandem mass spectrometry analysis revealing the class and fatty acyl-chain for lipids, batch photochemical derivatization and single-cell droplet treatment are performed to identify the C=C locations and sn-positions of lipids, respectively. Electro-migration combined with droplet-assisted electrospray ionization enables single-cell mass spectrometry analysis with easy operation but high efficiency in sample usage. Four subtypes of human breast cancer cells are correctly classified through quantitative analysis of lipid C=C location or sn-position isomers in ~160 cells. Most importantly, the single-cell deep lipidomics strategy successfully discriminates gefitinib-resistant cells from a population of wild-type human lung cancer cells (HCC827), highlighting its unique capability to promote precision medicine.

Histone Deacetylase Inhibition Regulates Lipid Homeostasis in a Mouse Model of Amyotrophic Lateral Sclerosis

“…In vitro studies will help us answer the question of the contribution of individual cell types, even if these systems lack the complete environment and the crosstalk between neurons and glial cells necessary for lipid homeostasis. Moreover, the development of in vivo single-cell lipidomic will revolutionize the field in the near future [ 61 ].…”

A Comprehensive Review of Lipidomics and Its Application to Assess Food Obtained from Farm Animals

“… Li et al (2021e) recently reported that the single cell lipidomics based on shotgun MS was established. This method involved MS/MS to reveal the class and fatty acyl chains of lipids, as well as the C=C locations and sn -positions of lipids.…”

“…Furthermore, electro-migration combined with droplet-assisted ESI made MS analyses not only simple but also efficient. Using the combination of chemical derivatization and MS/MS appears to be feasible for the highly complex structural analysis of lipid molecules in a single cell, and this method effectively overcomes problems associated with the limited sample amounts available ( Li et al, 2021e ). Thus, chemical derivatization coupled with MS/MS could become the important method for single-cell biology and precision medicine.…”

Lipid Profiling in Cancer Diagnosis with Hand-Held Ambient Mass Spectrometry Probes: Addressing the Late-Stage Performance Concerns

“…Of notable importance is a study of lipid metabolism in breast cancer that suggests a differential role of essential and non-essential lipids in metabolic profiles of inflammatory and cancer cells within the tumour tissue [91]. In the absence of spatially resolved ambient MS analysis (or single cell lipidomics [93]), to better capture these heterogeneities, alongside those arising from metabolic adaptability of cells to their environment [94], at the very least, a large population base must be included in the analysis, particularly in the initial model building stage. The issue of spatial resolution (often not at single cell levels in prominent ambient MS methods) causes sensitivity of signal to tumour cellularity, as shown in a DESI-MS lipidomic profiling study of brain cancers [95] and the localization of high 2-hydroxyglutarate (2HG) signal levels in the regions of glioblastoma tumours with a dense cellularity [10].…”