Fiber-type-specific architecture and pathophysiology of the neuromuscular junction

IF 3.3 3区医学 Q2 NEUROSCIENCES

Neuroscience Pub Date : 2026-03-17 Epub Date: 2026-01-16 DOI:10.1016/j.neuroscience.2026.01.015

Rizwan Qaisar

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引用次数: 0

Abstract

The neuromuscular junction (NMJ) is a specialized synapse essential for translating neuronal signals into muscle contraction. This review examines the complex structural, functional, and molecular differences in NMJs that innervate fast- and slow-twitch skeletal muscle fibers. Fast-twitch fibers, optimized for rapid and powerful contractions, possess elaborate NMJs with deep folds, high neurotransmitter turnover, and greater vulnerability to synaptic fatigue and degeneration. In contrast, slow-twitch fiber NMJs exhibit simpler but more stable architectures that support sustained, fatigue-resistant activity.

These differences are not fixed but subject to activity-dependent plasticity and pathological remodeling. Chronic stimulation, injury, and aging influence NMJ morphology, with fast-twitch junctions more prone to degeneration in conditions such as ALS, myasthenia gravis, and diabetic neuropathy. Slow-twitch NMJs often resist early deterioration due to superior trophic support, metabolic stability, and more robust expression of synaptic organizers, such as agrin and PGC-1α.

Several key signaling pathways, including agrin–MuSK–LRP4, Wnt/β-catenin, and neuregulin/ErbB, govern NMJ maintenance with fiber-type-specific nuances. These insights underscore the importance of tailoring therapeutic strategies to the muscle fiber phenotype. Gene therapies, neuromuscular electrical stimulation, and biomaterial scaffolds are emerging as promising modalities for preserving or restoring NMJ integrity, especially in fast-twitch fibers at higher risk of degeneration.

Understanding fiber-type-specific NMJ biology enhances our understanding of motor control, muscle aging, and neuromuscular disease progression, and it opens pathways for precision therapeutics that target vulnerable synapses with structural and functional specificity. This review introduces a novel perspective by emphasizing fiber-type-specific NMJ differences and their implications for targeted therapies.

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神经肌肉连接处的纤维类型特异性结构和病理生理学。

神经肌肉连接（NMJ）是一种特殊的突触，是将神经元信号转化为肌肉收缩所必需的。本文综述了支配快缩和慢缩骨骼肌纤维的NMJs的复杂结构、功能和分子差异。快速抽搐纤维，优化为快速和强大的收缩，具有复杂的NMJs深褶皱，高神经递质周转率，更容易受到突触疲劳和退化。相比之下，慢肌纤维NMJs表现出更简单但更稳定的结构，支持持续的抗疲劳活动。这些差异不是固定的，而是受活动依赖性可塑性和病理性重塑的影响。慢性刺激、损伤和衰老影响NMJ形态，在ALS、重症肌无力和糖尿病神经病变等情况下，快速抽搐连接更容易发生变性。由于优越的营养支持、代谢稳定性和更强的突触组织者（如agrin和PGC-1α）表达，慢抽搐NMJs通常能够抵抗早期退化。几种关键的信号通路，包括agrin-MuSK-LRP4、Wnt/β-catenin和neuregulin/ErbB，通过纤维类型特异性的细微差别控制NMJ的维持。这些见解强调了针对肌纤维表型定制治疗策略的重要性。基因疗法、神经肌肉电刺激和生物材料支架正在成为保存或恢复NMJ完整性的有希望的方式，特别是在变性风险较高的快肌纤维中。了解纤维类型特异性的NMJ生物学增强了我们对运动控制、肌肉老化和神经肌肉疾病进展的理解，并为针对结构和功能特异性的易损突触的精确治疗开辟了途径。这篇综述通过强调纤维类型特异性NMJ差异及其对靶向治疗的影响，介绍了一个新的观点。

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来源期刊

Neuroscience 医学-神经科学

CiteScore

6.20

自引率

0.00%

发文量

394

审稿时长

52 days

期刊介绍： Neuroscience publishes papers describing the results of original research on any aspect of the scientific study of the nervous system. Any paper, however short, will be considered for publication provided that it reports significant, new and carefully confirmed findings with full experimental details.