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

Abstract

Lipids in skeletal muscle play a fundamental role both in normal muscle metabolism and in disease states. Skeletal muscle lipid accumulation is associated with several chronic metabolic disorders, including obesity, insulin resistance, and type 2 diabetes. However, it is poorly understood whether the lipid composition of skeletal muscle changes by contraction, due to the complexity of lipid molecular species. In this study, we used matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS) to investigate changes in skeletal muscle lipid composition induced by contraction. We successfully observed the reduction of diacylglycerol and triacylglycerol, which are generally associated with muscle contraction. Interestingly, we found the accumulation of some saturated and mono-unsaturated fatty acids and poly-unsaturated fatty acids containing phosphatidylcholine in contracted muscles. Moreover, the distributions of several types of lipid were changed by contraction. Our results show that changes in the lipid amount, lipid composition, and energy metabolic activity can be evaluated in each local spot of cells and tissues at the same time using MALDI-IMS. In conclusion, MALDI-IMS is a powerful tool for studying lipid changes associated with contractions.

MALDI Imaging Mass Spectrometry—A Mini Review of Methods and Recent Developments

“…An example of such extended ratio analysis is visualization of energy charge, which was introduced to characterize metabolic energy state using number of phosphorylation sites calculated from abundance of ATP, ADP, and AMP. 36,37) In the near future, various visualizations will be performed, based on more complex theoretical ideas.…”

Visualization of lipids in skeletal muscles by mass spectrometry imaging

“…We applied MALDI-MSI to mouse skeletal muscle to demonstrate the change in lipid quality that occurs due to acute contraction 16) . In this study, we successfully observed the reduction of diacylglycerol and TAG, which are generally associated with muscle contraction.…”

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

“…However, it is poorly understood what types of molecular species are changed by muscle contractions due to the complexity and variety of lipid molecular species. In the present study, MALDI-IMS was used to analyze lipid metabolism 19) . Fig.…”