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hnRNP L is essential for myogenic differentiation and modulates myotonic dystrophy pathologies
Author(s) -
Alexander Matthew S.,
Hightower Rylie M.,
Reid Andrea L.,
Bennett Alexis H.,
Iyer Lakshmanan,
Slonim Donna K.,
Saha Madhurima,
Kawahara Genri,
Kunkel Louis M.,
Kopin Alan S.,
Gupta Vandana A.,
Kang Peter B.,
Draper Isabelle
Publication year - 2021
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.27216
Subject(s) - myotonic dystrophy , morpholino , biology , rna splicing , zebrafish , myocyte , rna binding protein , microbiology and biotechnology , myogenesis , muscular dystrophy , alternative splicing , downregulation and upregulation , trinucleotide repeat expansion , genetics , rna , messenger rna , gene , allele
Abstract Introduction RNA‐binding proteins (RBPs) play an important role in skeletal muscle development and disease by regulating RNA splicing. In myotonic dystrophy type 1 (DM1), the RBP MBNL1 (muscleblind‐like) is sequestered by toxic CUG repeats, leading to missplicing of MBNL1 targets. Mounting evidence from the literature has implicated other factors in the pathogenesis of DM1. Herein we sought to evaluate the functional role of the splicing factor hnRNP L in normal and DM1 muscle cells. Methods Co‐immunoprecipitation assays using hnRNPL and MBNL1 expression constructs and splicing profiling in normal and DM1 muscle cell lines were performed. Zebrafish morpholinos targeting hnrpl and hnrnpl2 were injected into one‐cell zebrafish for developmental and muscle analysis. In human myoblasts downregulation of hnRNP L was achieved with shRNAi. Ascochlorin administration to DM1 myoblasts was performed and expression of the CUG repeats, DM1 splicing biomarkers, and hnRNP L expression levels were evaluated. Results Using DM1 patient myoblast cell lines we observed the formation of abnormal hnRNP L nuclear foci within and outside the expanded CUG repeats, suggesting a role for this factor in DM1 pathology. We showed that the antiviral and antitumorigenic isoprenoid compound ascochlorin increased MBNL1 and hnRNP L expression levels. Drug treatment of DM1 muscle cells with ascochlorin partially rescued missplicing of established early biomarkers of DM1 and improved the defective myotube formation displayed by DM1 muscle cells. Discussion Together, these studies revealed that hnRNP L can modulate DM1 pathologies and is a potential therapeutic target.