Profiling and quantifying endogenous molecules in single cells using nano-DESI MS

Abstract

Molecular profiling of single cells has the potential to significantly advance our understanding of cell function and cellular processes of importance to health and disease. In particular, small molecules with rapid turn-over rates can reveal activated metabolic pathways resulting from an altered chemical environment or cellular events such as differentiation. Consequently, techniques for quantitative metabolite detection acquired in a higher throughput manner are needed to characterize the biological variability between seemingly homogenous cells. Here, we show that nanospray desorption electrospray ionization (nano-DESI) mass spectrometry (MS) enables sensitive molecular profiling and quantification of endogenous species in single cells in a higher throughput manner. Specifically, we show a large number of detected amino acids and phospholipids, including plasmalogens, readily detected from single cheek cells. Further, by incorporating a phosphatidylcholine (PC) internal standard into the nano-DESI solvent, we determined the total amount of PC in one cell to be 1.2 pmoles. Finally, we describe a higher throughput approach where molecules in single cells are automatically profiled. These developments in single cell analysis provide a basis for future studies to understand cellular processes related to drug effects, cell differentiation and altered chemical microenvironments.

CpG preconditioning reduces accumulation of lysophosphatidylcholine in ischemic brain tissue after middle cerebral artery occlusion

“…The primary capillary delivers the solvent to the liquid bridge and the secondary capillary transfers the liquid and extracted molecules to the mass spectrometer inlet where molecules are ionized by nanoelectrospray ionization. Nano-DESI MSI [27][28][29][30] has been used to study nicotine distribution in rat brain tissue [31], metabolite diffusion from live bacterial colonies [32], imaging of lipids and metabolites in different types of tissues with moderate and high spatial resolution [33][34][35], MS/MS imaging of lipids and metabolites in mouse embryo implantation sites [36], and quantitative MSI of low abundance molecular species [37][38][39].…”

Single‐Cell Mass Spectrometry Approaches to Explore Cellular Heterogeneity

“…[100] Laser ablation based sampling methods for ambient single-cell MS mainly include laser ablation electrospray ionization (LAESI), laser desorption ionization droplet delivery (LDIDD), and atmospheric pressure MALDI (AP-MALDI) approaches.LAESI uses an etched optical fiber tip to deliver mid-IR laser pulses to individual cells of interest for ablation and ESI for ionization of the ablation plume. [100] Laser ablation based sampling methods for ambient single-cell MS mainly include laser ablation electrospray ionization (LAESI), laser desorption ionization droplet delivery (LDIDD), and atmospheric pressure MALDI (AP-MALDI) approaches.LAESI uses an etched optical fiber tip to deliver mid-IR laser pulses to individual cells of interest for ablation and ESI for ionization of the ablation plume.…”

Einzelzell‐Massenspektrometrie zur Untersuchung zellulärer Heterogenität

“…Die Nano‐Desorptions‐Elektrospray‐Ionisation (Nano‐DESI) nutzt eine Primärkapillare zur Solvensabgabe an Zellproben und eine Sekundärkapillare zur Aufnahme der extrahierten Verbindungen für die Massenanalyse. Die kürzlich beschriebene Anwendung dieser Technik auf die Molekülbildgebung der metabolischen und lipidomischen Analyse einer Verteilung menschlicher Zellen der Wangenschleimhaut ergibt einen höheren Durchsatz …”