Morpholino treatment improves muscle function and pathology of Pitx1 transgenic mice.
Paired-like homeodomain transcription factor 1 (PITX1) was proposed to be part of the disease mechanisms of facioscapulohumeral muscular dystrophy (FSHD). We generated a tet-repressible muscle-specific Pitx1 transgenic mouse model which develops phenotypes of muscular dystrophy after the PITX1 expression is induced. In this study, we attempted to block the translation of PITX1 protein using morpholinos. Three groups of the transgenic mice received intravenous injections of phosphorodiamidate morpholino oligomers (PMO) (100 mg/kg), octaguanidinium dendrimer-conjugated morpholino (vivo-morpholino) (10 mg/kg), or phosphate-buffered saline (PBS) after the PITX1 expression was induced. Immunoblotting data showed that PITX1 expression in the triceps and quadriceps was significantly reduced 70% and 63% by the vivo-morpholino treatment, respectively. Muscle pathology of the mice treated with the vivo-morpholino was improved by showing 44% fewer angular-shaped atrophic myofibers. Muscle function determined by grip strength was significantly improved by the vivo-morpholino treatment. The study showed that systemic delivery of the vivo-morpholino reduced the PITX1 expression and improved the muscle phenotypes. Aberrant expression of DUX4 from the last unit of the D4Z4 array has been proposed to be the cause of FSHD. The findings of this study suggest that the same principle may be applied to suppress the aberrantly expressed DUX4 in FSHD.
Center for Genetic Medicine Research, Children's National Medical Center, Washington DC, USA.
Sachchida Nand
SN
Pandey
Center for Genetic Medicine Research, Children's National Medical Center, Washington DC, USA; Department of Biochemistry and Molecular Biology, George Washington University, Washington DC, USA.
Yi-Chien
YC
Lee
Department of Medical Genetics, University of Alberta Faculty of Medicine and Dentistry, Edmonton, Alberta, Canada.
Toshifumi
T
Yokota
Center for Genetic Medicine Research, Children's National Medical Center, Washington DC, USA; Department of Integrative Systems Biology, George Washington University, Washington DC, USA. Electronic address: ychen@childrensnational.org.
Yi-Wen
YW
Chen
D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D005786:Gene Expression Regulation; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D060172:Morpholinos / Q000008:administration & dosage* / Q000009:adverse effects / Q000235:genetics*; D053580:Muscle Strength / Q000187:drug effects / Q000235:genetics; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism* / Q000473:pathology; D020391:Muscular Dystrophy, Facioscapulohumeral / Q000235:genetics* / Q000534:rehabilitation / Q000628:therapy*; D051761:Paired Box Transcription Factors / Q000235:genetics* / Q000378:metabolism
D060172:Morpholinos; D051761:Paired Box Transcription Factors; C101485:homeobox protein PITX1