Abstract
Modification of K+ currents by exogenous gene expression may lead to therapeutic interventions in skeletal muscle diseases characterized by alterations in electrical excitability. In order to study the specific effects of increasing outward K+ currents, we expressed a modified voltage-dependent K+ channel in primary cultured rat skeletal muscle cells. The rat Kv1.4 channel was expressed as an N-terminal fusion protein containing a bioluminescent marker (green fluorescent protein). Transgene expression was carried out using the helper-dependent herpes simplex 1 amplicon system. Transduced myoballs, identified using fluorescein optics and studied electrophysiologically with single-cell patch clamp, exhibited a greater than two-fold increase in K+ conductance by 20-30 h after infection. This increase in K+ current led to a decrease in membrane resistance and a 10-fold increase in the current threshold for action potential generation. Electrical hyperexcitability induced by the Na+ channel toxin anemone toxin II (1 μM) was effectively counteracted by overexpression of Kv1.4 at 30-32 h after transduction. Thus, virally induced overexpression of a voltage-gated K+ channel in skeletal muscle has a powerful effect in reducing electrical excitability.
Original language | English (US) |
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Pages (from-to) | 1372-1379 |
Number of pages | 8 |
Journal | Gene Therapy |
Volume | 8 |
Issue number | 18 |
DOIs | |
State | Published - 2001 |
Keywords
- Anemone toxin II
- Green fluorescent protein
- Herpes simplex 1 amplicon system
- Hyperkalemic periodic paralysis
- Kv1.4
- Primary muscle culture
ASJC Scopus subject areas
- Molecular Medicine
- Molecular Biology
- Genetics