Mouse model characterization and in vivo testing of gene therapies for Facioscapulohumeral Muscular Dystrophy

Mouse model characterization and in vivo testing of gene therapies for Facioscapulohumeral Muscular Dystrophy

Bibliographic Details
Main Author: Giesige, Carlee Rae
Language:English
Published: The Ohio State University / OhioLINK 2018
Subjects:
Biology
Medicine
Genetics
DUX4
FSHD
Facioscapulohumeral Muscular Dystrophy
follistatin
AAV
animal models
Online Access:http://rave.ohiolink.edu/etdc/view?acc_num=osu153193150617187
id ndltd-OhioLink-oai-etd.ohiolink.edu-osu153193150617187
record_format oai_dc
collection NDLTD
language English
sources NDLTD
topic Biology
Medicine
Genetics
DUX4
FSHD
Facioscapulohumeral Muscular Dystrophy
follistatin
AAV
animal models
spellingShingle Biology
Medicine
Genetics
DUX4
FSHD
Facioscapulohumeral Muscular Dystrophy
follistatin
AAV
animal models
Giesige, Carlee Rae
Mouse model characterization and in vivo testing of gene therapies for Facioscapulohumeral Muscular Dystrophy
author Giesige, Carlee Rae
author_facet Giesige, Carlee Rae
author_sort Giesige, Carlee Rae
title Mouse model characterization and in vivo testing of gene therapies for Facioscapulohumeral Muscular Dystrophy
title_short Mouse model characterization and in vivo testing of gene therapies for Facioscapulohumeral Muscular Dystrophy
title_full Mouse model characterization and in vivo testing of gene therapies for Facioscapulohumeral Muscular Dystrophy
title_fullStr Mouse model characterization and in vivo testing of gene therapies for Facioscapulohumeral Muscular Dystrophy
title_full_unstemmed Mouse model characterization and in vivo testing of gene therapies for Facioscapulohumeral Muscular Dystrophy
title_sort mouse model characterization and in vivo testing of gene therapies for facioscapulohumeral muscular dystrophy
publisher The Ohio State University / OhioLINK
publishDate 2018
url http://rave.ohiolink.edu/etdc/view?acc_num=osu153193150617187
work_keys_str_mv AT giesigecarleerae mousemodelcharacterizationandinvivotestingofgenetherapiesforfacioscapulohumeralmusculardystrophy
_version_ 1719454474616963072
spelling ndltd-OhioLink-oai-etd.ohiolink.edu-osu1531931506171872021-08-03T07:07:43Z Mouse model characterization and in vivo testing of gene therapies for Facioscapulohumeral Muscular Dystrophy Giesige, Carlee Rae Biology Medicine Genetics DUX4 FSHD Facioscapulohumeral Muscular Dystrophy follistatin AAV animal models Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant muscular dystrophy characterized by progressive and asymmetric weakness of facial, shoulder and limb muscles. FSHD is linked to aberrant expression of the DUX4 gene, which encodes a myotoxic transcription factor. The emergence of DUX4 as a primary pathogenic insult in FSHD represented a momentum shift in the field, as it enabled translational research for the first time. There is currently no treatment for FSHD. Therapy development requires an understanding of the disease mechanism, as well as some knowledge about the normal function of the underlying genes involved. For these areas of research, animal models have proven to be essential tools. The goal of this work was to develop and characterize a viable animal model that recapitulated FSHD-like phenotypes. To achieve this, we have taken two approaches to create an FSHD animal model. The first approach was to define the extent of functional equivalency between the human DUX4 gene, which has close homologs only in primates, and a distantly related mouse gene, called Dux. This work supported that Dux and DUX4 both can cause myotoxicity and that Dux could therefore potentially be used as a proxy for human DUX4 in mouse studies designed to understand the normal and disease function of both genes. This work also demonstrated that there were key divergences in DUX4 and Dux protein homology and function that must be accounted for when studying Dux as a substitute for DUX4. In addition, DUX4, not Dux, is the main driver of FSHD in humans. Thus, DUX4 inhibition may be a direct path to FSHD therapy. Since DUX4 is extremely toxic, DUX4-expressing animal model development has been difficult, but progress has been made, revealing that tight regulation of DUX4 expression is critical for creating a viable model that develops myopathic features that are useful as therapeutic outcome measures. Our second approach for creating an FSHD animal model was to develop a DUX4 transgenic model with tight control of DUX4 expression. Here we report an inducible FSHD mouse model – called TIC-DUX4 - that utilizes Tamoxifen (TAM)-Inducible CRE recombinase to turn on DUX4 in skeletal muscle. Uninduced TIC-DUX4 (i.e. DUX4-off) mice are born in Mendelian ratios, develop normally to adulthood, and are indistinguishable from wild-type animals. Induced animals display significantly reduced skeletal muscle force, impaired open field activity, muscle wasting, and histological indicators of muscular dystrophy, including increased central nuclei and inflammation. Importantly, these phenotypes are tunable; myopathy progresses slowly over many months at low doses of TAM, while high doses can be used to rapidly induce widespread myopathic phenotypes within 2 weeks. We are now using this model to test DUX4-targeted gene therapies and myostatin inhibition to prevent DUX4 induced muscle weakness and increase muscle strength respectively. To directly target DUX4 expression, we utilized the RNAi pathway by AAV delivery of a DUX4-targeted microRNA. This provided long-term protection from DUX4-associated damage in old induced TIC-DUX4 mice. We also tested AAV delivery of follistatin by directly injecting virus into tibialis anterior and gastroc muscles of TIC-DUX4 mice. Follistatin expression significantly increased muscle mass and total muscle strength in the presence of DUX4 expression after 8 weeks of induction. These data will support translation of gene therapies for FSHD, and the TIC-DUX4 mouse model will be useful for testing other FSHD therapies as they emerge. 2018 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu153193150617187 http://rave.ohiolink.edu/etdc/view?acc_num=osu153193150617187 restricted--full text unavailable until 2023-08-06 This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.

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