Related Experiment Video
Updated: Nov 15, 2025
Characterization of Neuromuscular Junctions in Mice by Combined Confocal and Super-Resolution Microscopy
Published on: December 8, 2021
Early differences in membrane properties at the neuromuscular junctions of ALS model mice: Effects of
Guzel F Zakyrjanova1, Arthur R Giniatullin2, Kamilla A Mukhutdinova3
1Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky Street, box 30, Kazan 420111, Russia; Institute of Neuroscience, Kazan State Medial University, 49 Butlerova Street, Kazan, 420012, Russia.
Aims:
Plasma hyperlipidemia is a protective factor in amyotrophic lateral sclerosis (ALS) while cholesterol-lowering drugs aggravate the pathology. We hypothesize that this phenomenon can be linked with membrane lipid alterations in the neuromuscular junctions (NMJs) occurring before motor neuron loss.
Methods:
Neurotransmitter release in parallel with lipid membrane properties in diaphragm NMJs of SOD1G93A (mSOD) mice at nine weeks of age (pre-onset stage) were assessed.
Key Findings:
Despite on slight changes in spontaneous and evoked quantum release of acetylcholine, extracellular levels of choline at resting conditions, an indicator of non-quantum release, were significantly increased in mSOD mice. The use of lipid-sensitive fluorescent probes points to lipid raft disruption in the NMJs of mSOD mice. However, content of cholesterol, a key raft component was unchanged implying another pathway responsible for the loss of raft integrity. In the mSOD mice we found marked increase in levels of raft-destabilizing lipid ceramide. This was accompanied by enhanced ability to uptake of exogenous ceramide in NMJs. Acute and chronic administration of 25-hydroxycholesterol, whose levels increase due to hypercholesterolemia, recovered early alterations in membrane properties. Furthermore, chronic treatment with 25-hydroxycholesterol prevented increase in ceramide and extracellular choline levels as well as suppressed lipid peroxidation of NMJ membranes and fragmentation of end plates.
Significance:
Thus, lipid raft disruption likely due to ceramide accumulation could be early event in ALS which may trigger neuromuscular abnormalities. Cholesterol derivative 25-hydroxycholesterol may serve as a molecule restoring the membrane and functional properties of NMJs at the early stage.
