Myostatin inhibits proliferation of human urethral rhabdosphincter satellite cells.
OBJECTIVE
Myostatin, a member of the transforming growth factor-β superfamily, is a negative regulator of myogenesis in skeletal muscle. We examined the effect of myostatin and myostatin inhibition by an antagonistic agent, follistatin, on growth of human urethral rhabdosphincter satellite cells (muscle stem cells) to develop a new strategy for treatment of stress urinary incontinence.


METHODS
Rhabdosphincter satellite cells were cultured and selected by magnetic affinity cell sorting using an anti-neural cell adhesion molecule antibody. The cells were transfected with simian virus-40 antigen to extend their lifespan. A cell proliferation assay, a cell cycle analysis and an investigation of signal transduction were carried out. The autocrine action of endogenous myostatin by western blotting, real-time reverse transcription polymerase chain reaction and immunoneutralization using an anti-myostatin antibody was also evaluated.


RESULTS
Selectively cultured cells expressed markers of striated muscles and successfully differentiated into myotubes. Myostatin inhibited proliferation of these cells through Smad2 phosphorylation and cell cycle arrest. Inhibitory effects of myostatin were reversed by addition of follistatin. However, rhabdosphincter satellite cells did not appear to use autocrine secretion of myostatin to regulate their proliferation.


CONCLUSIONS
Inhibition of myostatin function might be a useful pathway in the development of novel strategies for stimulating rhabdosphincter cells regeneration to treat stress urinary incontinence.
Department of Urology, Faculty of Medicine, Oita University, Oita, Japan.
Yasuyuki
Y
Akita
Yasuhiro
Y
Sumino
Ken-ichi
K
Mori
Takeo
T
Nomura
Fuminori
F
Sato
Hiromitsu
H
Mimata
D019898:Autocrine Communication; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D004353:Drug Evaluation, Preclinical; D006801:Humans; D055435:Myostatin / Q000494:pharmacology* / Q000627:therapeutic use; D015398:Signal Transduction / Q000187:drug effects; D014521:Urethra / Q000187:drug effects*; D014550:Urinary Incontinence, Stress / Q000188:drug therapy*
D055435:Myostatin