Document Type

Journal Article

Publication Date

9-8-2015

Journal

Cell Reports

Volume

12

Issue

10

Inclusive Pages

1678-1690

DOI

10.1016/j.celrep.2015.07.066

Keywords

Dystrophin--genetics; MicroRNAs--genetics; Muscular Dystrophy, Duchenne--metabolism; Tumor Necrosis Factor-alpha--physiology

Abstract

The amount and distribution of dystrophin protein in myofibers and muscle is highly variable in Becker muscular dystrophy and in exon-skipping trials for Duchenne muscular dystrophy. Here, we investigate a molecular basis for this variability. In muscle from Becker patients sharing the same exon 45–47 in-frame deletion, dystrophin levels negatively correlate with microRNAs predicted to target dystrophin. Seven microRNAs inhibit dystrophin expression in vitro, and three are validated in vivo (miR-146b/miR-374a/miR-31). microRNAs are expressed in dystrophic myofibers and increase with age and disease severity. In exon-skipping-treated mdx mice, microRNAs are significantly higher in muscles with low dystrophin rescue. TNF-α increases microRNA levels in vitro whereas NFκB inhibition blocks this in vitro and in vivo. Collectively, these data show that microRNAs contribute to variable dystrophin levels in muscular dystrophy. Our findings suggest a model where chronic inflammation in distinct microenvironments induces pathological microRNAs, initiating a self-sustaining feedback loop that exacerbates disease progression.

Comments

Reproduced with permission of Elsevier B.V. Cell Reports.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Peer Reviewed

1

Open Access

1

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