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PLoS One DOI:10.1371/journal.pone.0093140

The role of muscle microRNAs in repairing the neuromuscular junction.

Publication TypeJournal Article
Year of Publication2014
AuthorsValdez, G, Heyer, MP, Feng, G, Sanes, JR
JournalPLoS One
Date Published2014
KeywordsAmyotrophic Lateral Sclerosis, Animals, Disease Models, Animal, Mice, Mice, Knockout, MicroRNAs, Muscle, Skeletal, Neuromuscular Junction, Superoxide Dismutase, Superoxide Dismutase-1

microRNAs have been implicated in mediating key aspects of skeletal muscle development and responses to diseases and injury. Recently, we demonstrated that a synaptically enriched microRNA, miR-206, functions to promote maintenance and repair of the neuromuscular junction (NMJ); in mutant mice lacking miR-206, reinnervation is impaired following nerve injury and loss of NMJs is accelerated in a mouse model of amyotrophic lateral sclerosis (ALS). Here, we asked whether other microRNAs play similar roles. One attractive candidate is miR-133b because it is in the same transcript that encodes miR-206. Like miR-206, miR-133b is concentrated near NMJs and induced after denervation. In miR-133b null mice, however, NMJ development is unaltered, reinnervation proceeds normally following nerve injury, and disease progression is unaffected in the SOD1(G93A) mouse model of ALS. To determine if miR-206 compensates for the loss of miR-133b, we generated mice lacking both microRNAs. The phenotype of these double mutants resembled that of miR-206 single mutants. Finally, we used conditional mutants of Dicer, an enzyme required for the maturation of most microRNAs, to generate mice in which microRNAs were depleted from skeletal muscle fibers postnatally, thus circumventing a requirement for microRNAs in embryonic muscle development. Reinnervation of muscle fibers following injury was impaired in these mice, but the defect was similar in magnitude to that observed in miR-206 mutants. Together, these results suggest that miR-206 is the major microRNA that regulates repair of the NMJ following nerve injury.


Alternate JournalPLoS ONE
PubMed ID24664281
PubMed Central IDPMC3963997
Grant ListT32 GM008441 / GM / NIGMS NIH HHS / United States
R01AG032322 / AG / NIA NIH HHS / United States