Campus Units

Animal Science

Document Type

Article

Publication Version

Published Version

Publication Date

2-2020

Journal or Book Title

Physiological Reports

Volume

8

Issue

4

First Page

e14383

DOI

10.14814/phy2.14383

Abstract

Duchenne muscular dystrophy (DMD) is caused by the absence of functional dystrophin protein and results in progressive muscle wasting. Dystrophin deficiency leads to a host of dysfunctional cellular processes including impaired autophagy. Autophagic dysfunction appears to be due, at least in part, to decreased lysosomal abundance mediated by decreased nuclear localization of transcription factor EB (TFEB), a transcription factor responsible for lysosomal biogenesis. PGC‐1α overexpression decreased disease severity in dystrophin‐deficient skeletal muscle and increased PGC‐1α has been linked to TFEB activation in healthy muscle. The purpose of this study was to determine the extent to which PGC‐1α overexpression increased nuclear TFEB localization, increased lysosome abundance, and increased autophagosome degradation. We hypothesized that overexpression of PGC‐1α would drive TFEB nuclear translocation, increase lysosome biogenesis, and improve autophagosome degradation. To address this hypothesis, we delivered PGC‐1α via adeno‐associated virus (AAV) vector injected into the right limb of 3‐week‐old mdx mice and the contralateral limbs received a sham injection. At 6 weeks of age, this approach increased PGC‐1α transcript by 60‐fold and increased TFEB nuclear localization in gastrocnemii from PGC‐1α treated limbs by twofold compared to contralateral controls. Furthermore, lamp2, a marker of lysosome abundance, was significantly elevated in muscles from limbs overexpressing PGC‐1α. Lastly, increased LC3II and similar p62 in PGC‐1α overexpressing‐limbs compared to contralateral limbs are supportive of increased degradation of autophagosomes. These data provide mechanistic insight into PGC‐1α‐mediated benefits to dystrophin‐deficient muscle, such that increased TFEB nuclear localization in dystrophin‐deficient muscle leads to increased lysosome biogenesis and autophagy.

Comments

This article is published as Spaulding, Hannah R., Amanda K. Ludwig, Katrin Hollinger, Matthew B. Hudson, and Joshua T. Selsby. "PGC‐1α overexpression increases transcription factor EB nuclear localization and lysosome abundance in dystrophin‐deficient skeletal muscle." Physiological reports 8, no. 4 (2020): e14383. doi: 10.14814/phy2.14383.

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

Copyright Owner

The Authors

Language

en

File Format

application/pdf

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