Post-transcriptional silencing of SCN1B and SCN2B genes modulates late sodium current in cardiac myocytes from normal dogs and dogs with chronic heart failure
| Autor: | Sudhish Mishra, Albertas I. Undrovinas, Victor A. Maltsev, Vitaliy Reznikov, Hani N. Sabbah, Nidas A. Undrovinas |
|---|---|
| Rok vydání: | 2011 |
| Předmět: |
medicine.medical_specialty
Pathology Patch-Clamp Techniques Physiology Blotting Western Action Potentials Biology Transfection Sodium Channels Dogs SCN1B RNA interference Physiology (medical) Internal medicine medicine Animals Myocyte Gene silencing Myocytes Cardiac Patch clamp RNA Small Interfering Cells Cultured Heart Failure Reverse Transcriptase Polymerase Chain Reaction Cardiac Excitation and Contraction Sodium channel Membrane Proteins medicine.disease Cardiovascular physiology Endocrinology Heart failure Chronic Disease RNA Interference Cardiology and Cardiovascular Medicine |
| Zdroj: | American Journal of Physiology-Heart and Circulatory Physiology. 301:H1596-H1605 |
| ISSN: | 1522-1539 0363-6135 |
| DOI: | 10.1152/ajpheart.00948.2009 |
| Popis: | The emerging paradigm for Na+ current in heart failure (HF) is that its transient component ( INaT) responsible for the action potential (AP) upstroke is decreased, whereas the late component ( INaL) involved in AP plateau is augmented. Here we tested whether Navβ1- and Navβ2-subunits can modulate INaL parameters in normal and failing ventricular cardiomyocytes (VCMs). Chronic HF was produced in nine dogs by multiple sequential coronary artery microembolizations, and six dogs served as a control. INa and APs were measured by the whole cell and perforated patch-clamp in freshly isolated and cultured VCMs, respectively. INaL was augmented with slower decay in HF VCMs compared with normal heart VCMs, and these properties remained unchanged within 5 days of culture. Post-transcriptional silencing SCN1B and SCN2B were achieved by virally delivered short interfering RNA (siRNA) specific to Navβ1 and Navβ2. The delivery and efficiency of siRNA were evaluated by green fluorescent protein expression, by the real-time RT-PCR, and Western blots, respectively. Five days after infection, the levels of mRNA and protein for Navβ1 and Navβ2 were reduced by >80%, but mRNA and protein of Nav1.5, as well as INaT, remained unchanged in HF VCMs. Navβ1-siRNA reduced INaL density and accelerated INaL two-exponential decay, whereas Navβ2-siRNA produced an opposite effect in VCMs from both normal and failing hearts. Physiological importance of the discovered INaL modulation to affect AP shape and duration was illustrated both experimentally and by numerical simulations of a VCM excitation-contraction coupling model. We conclude that in myocytes of normal and failing dog hearts Navβ1 and Navβ2 exhibit oppositely directed modulation of INaL. |
| Databáze: | OpenAIRE |
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