Plasma Membrane Lipid Composition and Turnover in Human Midbrain Neurons Investigated by Time-of-Flight Mass Spectrometry

The molecular structure and dynamics of the neuronal plasma membrane are essential for neuronal biology and function. We employed time-of-flight secondary ion mass spectrometry (ToF-SIMS) imaging to investigate the lipid composition and turnover at the plasma membrane of single human midbrain neurons. The results showed that the profile of lipid turnover was heavily influenced by the types of precursors incorporated into the membrane lipids. In addition, there was a high prevalence of phosphatidylcholines, phosphatidylserines, and ceramides in the human midbrain neurons, and a preference for incorporating stearic acid into membrane lipids compared to other precursors. These features indicate a direct link between the membrane lipids to the biological state and functions of midbrain neurons. This is among a very few studies using mass spectrometry imaging to provide an insight into the native membrane lipid organization and lipid turnover using various lipid precursors in human neurons at a single cell level, illustrating their biological relevance in neuronal functions.