BACKGROUND INFORMATION: Voltage-dependent sodium channels are membrane proteins essential for cell excitability. They are composed by a pore-forming α-subunit and one or more β subunits. Nine α subunit and five β subunit isoforms have been identified in mammals: β1, its splice variant β1B, β2, β3 and β4. Although they do not form the ion channel pore, β subunits modulate both function as well as expression of sodium channels on cell membrane. RESULTS: To investigate the role of β1 subunit on the modulation of sodium channel expression, we silenced this auxiliary subunit with specific antisense oligonucleotides (ASONs) in two rat cell lines, the GH3 and the H9C2, from neuro-ectoderm and cardiac myocyte origin, respectively. Treatment of cells with ASONs determined a reduction of about 50% of β1 subunit mRNA and protein expression in both cell lines. We found that this level of β1 subunit silencing resulted in an overall decrease of α subunit mRNA, protein expression and a decrease of sodium current density, without altering significantly the voltage-dependent and kinetic properties of the currents. In GH3 cells, the β1 subunit silencing reduced the expression of Nav1.1, Nav1.3 and Nav1.6 isoforms, whereas the Nav 1.2 isoform expression remained unaltered. The expression of the only α subunit present in H9C2 cells, the Nav1.5, was also reduced by β1 subunit silencing. CONCLUSIONS: These results indicate that the β1 subunit may exert an isoform-specific fine-tuned modulation of sodium channel expression.
BACKGROUND INFORMATION: Voltage-dependent sodium channels are membrane proteins essential for cell excitability. They are composed by a pore-forming α-subunit and one or more β subunits. Nine α subunit and five β subunit isoforms have been identified in mammals: β1, its splice variant β1B, β2, β3 and β4. Although they do not form the ion channel pore, β subunits modulate both function as well as expression of sodium channels on cell membrane. RESULTS: To investigate the role of β1 subunit on the modulation of sodium channel expression, we silenced this auxiliary subunit with specific antisense oligonucleotides (ASONs) in two rat cell lines, the GH3 and the H9C2, from neuro-ectoderm and cardiac myocyte origin, respectively. Treatment of cells with ASONs determined a reduction of about 50% of β1 subunit mRNA and protein expression in both cell lines. We found that this level of β1 subunit silencing resulted in an overall decrease of α subunit mRNA, protein expression and a decrease of sodium current density, without altering significantly the voltage-dependent and kinetic properties of the currents. In GH3 cells, the β1 subunit silencing reduced the expression of Nav1.1, Nav1.3 and Nav1.6 isoforms, whereas the Nav 1.2 isoform expression remained unaltered. The expression of the only α subunit present in H9C2 cells, the Nav1.5, was also reduced by β1 subunit silencing. CONCLUSIONS: These results indicate that the β1 subunit may exert an isoform-specific fine-tuned modulation of sodium channel expression.
Authors: Donatus O Onwuli; Laia Yañez-Bisbe; Mel Lina Pinsach-Abuin; Anna Tarradas; Ramon Brugada; John Greenman; Sara Pagans; Pedro Beltran-Alvarez Journal: Channels (Austin) Date: 2017-07-18 Impact factor: 2.581
Authors: Quentin Coquerel; Claire Legendre; Jacinthe Frangieh; Stephan De Waard; Jérôme Montnach; Leos Cmarko; Joseph Khoury; Charifat Said Hassane; Dimitri Bréard; Benjamin Siegler; Ziad Fajloun; Harold De Pomyers; Kamel Mabrouk; Norbert Weiss; Daniel Henrion; Pascal Richomme; César Mattei; Michel De Waard; Anne-Marie Le Ray; Christian Legros Journal: Molecules Date: 2022-06-28 Impact factor: 4.927
Authors: Kathryn R Brewer; Georg Kuenze; Carlos G Vanoye; Alfred L George; Jens Meiler; Charles R Sanders Journal: Front Pharmacol Date: 2020-05-04 Impact factor: 5.810