Local applications of myostatin-siRNA with atelocollagen increase skeletal muscle mass and recovery of muscle function

Emi Kawakami; Nobuhiko Kawai; Nao Kinouchi; Hiroyo Mori; Yutaka Ohsawa; Naozumi Ishimaru; Yoshihide Sunada; Sumihare Noji; Eiji Tanaka

doi:10.1371/journal.pone.0064719

Local applications of myostatin-siRNA with atelocollagen increase skeletal muscle mass and recovery of muscle function

PLoS One. 2013 May 22;8(5):e64719. doi: 10.1371/journal.pone.0064719. Print 2013.

Authors

Emi Kawakami¹, Nobuhiko Kawai, Nao Kinouchi, Hiroyo Mori, Yutaka Ohsawa, Naozumi Ishimaru, Yoshihide Sunada, Sumihare Noji, Eiji Tanaka

Affiliation

¹ Department of Orthodontics and Dentofacial Orthopedics, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan.

Abstract

Background: Growing evidence suggests that small-interfering RNA (siRNA) can promote gene silencing in mammalian cells without induction of interferon synthesis or nonspecific gene suppression. Recently, a number of highly specific siRNAs targeted against disease-causing or disease-promoting genes have been developed. In this study, we evaluate the effectiveness of atelocollagen (ATCOL)-mediated application of siRNA targeting myostatin (Mst), a negative regulator of skeletal muscle growth, into skeletal muscles of muscular dystrophy model mice.

Methods and findings: We injected a nanoparticle complex containing myostatin-siRNA and ATCOL (Mst-siRNA/ATCOL) into the masseter muscles of mutant caveolin-3 transgenic (mCAV-3Tg) mice, an animal model for muscular dystrophy. Scrambled (scr) -siRNA/ATCOL complex was injected into the contralateral muscles as a control. Two weeks after injection, the masseter muscles were dissected for histometric analyses. To investigate changes in masseter muscle activity by local administration of Mst-siRNA/ATCOL complex, mouse masseter electromyography (EMG) was measured throughout the experimental period via telemetry. After local application of the Mst-siRNA/ATCOL complex, masseter muscles were enlarged, while no significant change was observed on the contralateral side. Histological analysis showed that myofibrils of masseter muscles treated with the Mst-siRNA/ATCOL complex were significantly larger than those of the control side. Real-time PCR analysis revealed a significant downregulation of Mst expression in the treated masseters of mCAV-3Tg mice. In addition, expression of myogenic transcription factors was upregulated in the Mst-siRNA-treated masseter muscle, while expression of adipogenic transcription factors was significantly downregulated. EMG results indicate that masseter muscle activity in mCAV-3Tg mice was increased by local administration of the Mst-siRNA/ATCOL complex.

Conclusion: These data suggest local administration of Mst-siRNA/ATCOL complex could lead to skeletal muscle hypertrophy and recovery of motor disability in mCAV-3Tg mice. Therefore, ATCOL-mediated application of siRNA is a potential tool for therapeutic use in muscular atrophy diseases.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Collagen / administration & dosage*
Collagen / pharmacology
Electromyography
Masseter Muscle / anatomy & histology*
Masseter Muscle / physiology
Mice
Mice, Transgenic
Myostatin / genetics*
Organ Size / drug effects*
RNA, Small Interfering / administration & dosage*
RNA, Small Interfering / genetics
RNA, Small Interfering / pharmacology

Substances

Myostatin
RNA, Small Interfering
atelocollagen
Collagen

Grants and funding

This work was supported partially by an Intramural Research Grant (23-5) for Neurological and Psychiatric Disorders of NCNP and a Grant (No. 23659966) for Science Research from the Ministry of Education, Science and Culture, Japan. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.