Neuromuscular junction mitochondrial enrichment: a “double-edged sword” underlying the selective motor neuron vulnerability in amyotrophic lateral sclerosis

摘要

Motor neurons are highly polarized cells,with long axons that extend to more than 1 m in the adult human.The axons further arborize into a specialized synaptic compartment,the motor unit,containing up to 2000 neuromuscular junctions(NMJs).While the size of other neuronal synapses can be up to 1μm,the NMJ is much larger and can reach 10–30μm(Jones et al.,2017).The vast size of the motor unit requires motor neurons to evolutionally adapt and supply this distal portion with a sufficient amount of ATP,as well as to replenish the axonal protein pool in order to maintain their synapses.