Tumor necrosis factor alpha mediates neuromuscular synapse elimination

Xiu-Qing Fu; Jian Peng; Ai-Hua Wang; Zhen-Ge Luo

doi:10.1038/s41421-020-0143-5

Tumor necrosis factor alpha mediates neuromuscular synapse elimination

Cell Discov. 2020 Mar 3:6:9. doi: 10.1038/s41421-020-0143-5. eCollection 2020.

Authors

Xiu-Qing Fu¹, Jian Peng^{1

2

3}, Ai-Hua Wang¹, Zhen-Ge Luo¹

Affiliations

¹ 1School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210 China.
² 2State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Institute of Neuroscience, Chinese Academy of Sciences, Shanghai, 200031 China.
³ 3University of Chinese Academy of Sciences, Beijing, 100049 China.

Abstract

During the development of mammalian neuromuscular junction (NMJ), the original supernumerary axon inputs are gradually eliminated, finally leaving each muscle fiber innervated by a single axon terminal. However, the molecular cues that mediate the elimination of redundant axon inputs remain unclear. Here we show that tumor necrosis factor-α (TNFα) expressed in postsynaptic muscle cells plays an important role in presynaptic axonal elimination at the NMJ. We found that intramuscular injection of TNFα into the levator auris longus (LAL) muscles caused disassociation of presynaptic nerve terminals from the postsynaptic acetylcholine receptor (AChR) clusters. By contrast, genetic ablation of TNFα globally or specifically in skeletal muscle cells, but not in motoneurons or Schwann cells, delayed the synaptic elimination. Moreover, ablation of TNFα in muscle cells attenuated the tendency of activity-dependent competition in a motoneuron-muscle coculture system. These results suggest a role of postsynaptic TNFα in the elimination of redundant synaptic inputs.

Keywords: Cell biology; Developmental biology.