Abstract
Changes in the expression of potassium channels regulate skeletal muscle development. The purpose of this study was to investigate the expression profile and pharmacological role of Kv7 voltage-gated potassium channels in skeletal muscle differentiation, proliferation, and survival after myotoxic insults. Transcripts for all Kv7 genes (Kv7.1–Kv7.5) were detected by polymerase chain reaction (PCR) and/or real-time PCR in murine C2C12 myoblasts; Kv7.1, Kv7.3, and Kv7.4 transcripts were up-regulated after myotube formation. Western blot experiments confirmed Kv7.2, Kv7.3, and Kv7.4 subunit expression, and the up-regulation of Kv7.3 and Kv7.4 subunits during in vitro differentiation. In adult skeletal muscles from mice and humans, Kv7.2 and Kv7.3 immunoreactivity was mainly localized at the level of intracellular striations positioned between ankyrinG-positive triads, whereas that of Kv7.4 subunits was largely restricted to the sarcolemmal membrane. In C2C12 cells, retigabine (10 μM), a specific activator of neuronally expressed Kv7.2 to Kv7.5 subunits, reduced proliferation, accelerated myogenin expression, and inhibited the myotoxic effect of mevastatin (IC50 ≈ 7 μM); all these effects of retigabine were prevented by the Kv7 channel blocker 10,10-bis(4-pyridinylmethyl)-9(10H)-anthracenone (XE-991) (10 μM). These data collectively highlight neural Kv7 channels as significant pharmacological targets to regulate skeletal muscle proliferation, differentiation, and myotoxic effects of drugs.
Footnotes
This work was supported by ERA-Net for Research Programs on Rare Disease (E-Rare 2007) Telethon Fondazione ONLUS, Italy [Grant GGP07125]; Regione Molise; and the Italian Ministry of Education, University, and Research (PRIN 2007); and Italian Ministry of Health (Progetto Doping 2005). (M.T.).
Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.
doi:10.1124/jpet.109.162800.
↵ The online version of this article (available at http://jpet.aspetjournals.org) contains supplemental material.
-
ABBREVIATIONS:
- XE-991
- 10,10-bis(4-pyridinylmethyl)-9(10H)-anthracenone
- IKM
- M-current
- GM
- growth medium
- DM
- differentiation medium
- MyHC
- myosin heavy chain
- AnkG
- ankyrin-G
- MEV
- mevastatin
- FBS
- fetal bovine serum
- CHO
- Chinese hamster ovary
- PCR
- polymerase chain reaction
- RT-PCR
- reverse transcription-polymerase chain reaction
- MTT
- 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide
- PBS
- phosphate-buffered saline
- OD
- optical density.
- Received October 19, 2009.
- Accepted December 16, 2009.
- Copyright © 2010 by The American Society for Pharmacology and Experimental Therapeutics
JPET articles become freely available 12 months after publication, and remain freely available for 5 years.Non-open access articles that fall outside this five year window are available only to institutional subscribers and current ASPET members, or through the article purchase feature at the bottom of the page.
|