Detection of characteristic distributions of phospholipid head groups and fatty acids on neurite surface by time-of-flight secondary ion mass spectrometry

Abstract

Neurons have a large surface because of their long and thin neurites. This surface is composed of a lipid bilayer. Lipids have not been actively investigated so far because of some technical difficulties, although evidence from cell biology is emerging that lipids contain valuable information about their roles in the central nervous system. Recent progress in techniques, e.g., mass spectrometry, opens a new epoch of lipid research. We show herein the characteristic localization of phospholipid components in neurites by means of time-of-flight secondary ion mass spectrometry. We used explant cultures of mouse superior cervical ganglia, which are widely used by neurite investigation research. In a positive-ion detection mode, phospholipid head group molecules were predominantly detected. The ions of m/z 206.1 [phosphocholine, a common component of phosphatidylcholine (PC) and sphingomyelin (SM)] were evenly distributed throughout the neurites, whereas the ions of m/z 224.1, 246.1 (glycerophosphocholine, a part of PC, but not SM) showed relatively strong intensity on neurites adjacent to soma. In a negative-ion detection mode, fatty acids such as oleic and palmitic acids were mainly detected, showing high intensity on neurites adjacent to soma. Our results suggest that lipid components on the neuritic surface show characteristic distributions depending on neurite region.

Visualization of dynamic change in contraction-induced lipid composition in mouse skeletal muscle by matrix-assisted laser desorption/ionization imaging mass spectrometry

“…The authors demonstrated the distribution of small lipids (lower than m/z 800) with high spatial resolution in some dystrophic tissue and obese model mice [13,14]. TOF-SIMS is a superior tool for highspatial-resolution IMS (submicron order) of elements and small molecules at different organelle levels of the cell [15]. However, due to the in-source fragmentation and the lack of tandem mass spectrometric facility, SIMS lacks sensitivity for the mass range over m/z 800 and the ability to identify molecules.…”

Loss of lymphatic vessels and regional lipid accumulation is associated with great saphenous vein incompetence

“…Although the range of biochemical effects of PC (diacyl 16:0/20:4) is uncertain, elevated levels of the molecule have been reported in mammalian tissues with chronic inflammation. 3,4 We observed that PC (diacyl 16:0/20:4) contains arachidonic acid, which is a precursor to lipid mediators such as proinflammatory prostaglandins and leukotrienes. Taken together, these data indicate that the elevated tissue content of PC (diacyl 16:0/20:4) may be associated with chronic inflammation in the incompetent GSV.…”

“…1 IMS revealed the accumulation of lysophosphatidylcholine (LPC; 1-acyl 16:0) and phosphatidylcholine (PC; diacyl 16:0/20:4) in the valvular region. Because these molecules are potential proinflammatory lipids, [2][3][4] this finding suggests that LPC and PC are involved in the development of tissue inflammation and valvular incompetence. These results support previously reported data.…”

Visualization of metabolite change in skeletal muscle by contraction using imaging mass spectrometry

“…They showed that vita-*Correspondence: fujiin@tmu.ac.jp min E and phosphatidylinositols concentrated within the cells, whereas intact phosphocholines accumulated over the most damaged areas of dystrophic muscle, together with cholesterol and sphingomyelin (SM) species. TOF-SIMS is an excellent tool for high-spatial-resolution IMS (submicron order) of elements and small molecules at different organelle levels of the cell 17) . However, due to in-source fragmentation and the lack of tandem mass spectrometric facility to identify the structure, SIMS lacks sensitivity for the mass range over m/z 800 and the ability to identify molecules.…”