title: A novel strategy using cardiac sodium channel polymorphic fragments to rescue trafficking-deficient SCN5A mutations.
abstract: BACKGROUND
  Brugada syndrome (BrS) is associated with mutations in the cardiac sodium channel (Na(v)1.5). We previously reported that the function of a trafficking-deficient BrS Na(v)1.5 mutation, R282H, could be restored by coexpression with the sodium channel polymorphism H558R. Here, we tested the hypothesis that peptide fragments from Na(v)1.5, spanning the H558R polymorphism, can be used to restore trafficking of trafficking-deficient BrS sodium channel mutations.
  
  
  RESULTS
  Whole-cell patch clamping revealed that cotransfection in human embryonic kidney (HEK293) cells of the R282H channel with either the 40- or 20-amino acid cDNA fragments of Na(v)1.5 containing the H558R polymorphism restored trafficking of this mutant channel. Fluorescence resonance energy transfer suggested that the trafficking-deficient R282H channel was misfolded, and this was corrected on coexpression with R558-containing peptides that restored trafficking of the R282H channel. Importantly, we also expressed the peptide spanning the H558R polymorphism with 8 additional BrS Na(v)1.5 mutations with reduced currents and demonstrated that the peptide was able to restore significant sodium currents in 4 of them.
  
  
  CONCLUSIONS
  In the present study, we demonstrate that small peptides, spanning the H558R polymorphism, are sufficient to restore the trafficking defect of BrS-associated Na(v)1.5 mutations. Our findings suggest that it might be possible to use short cDNA constructs as a novel strategy tailored to specific disease-causing mutants of BrS.
authors.affiliation: Heart and Vascular Research Center, Department of Medicine, MetroHealth Campus, Case Western Reserve University, Cleveland, OH 44109, USA.
authors.forename: Krekwit
authors.initials: K
authors.lastname: Shinlapawittayatorn
authors.forename: Lynn A
authors.initials: LA
authors.lastname: Dudash
authors.forename: Xi X
authors.initials: XX
authors.lastname: Du
authors.forename: Lisa
authors.initials: L
authors.lastname: Heller
authors.forename: Steven
authors.initials: S
authors.lastname: Poelzing
authors.forename: Eckhard
authors.initials: E
authors.lastname: Ficker
authors.forename: Isabelle
authors.initials: I
authors.lastname: Deschênes
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D053840:Brugada Syndrome / Q000235:genetics / Q000473:pathology; D002460:Cell Line; D031541:Fluorescence Resonance Energy Transfer; D005822:Genetic Vectors / Q000737:chemistry / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D062554:NAV1.5 Voltage-Gated Sodium Channel; D018408:Patch-Clamp Techniques; D010455:Peptides / Q000494:pharmacology; D011110:Polymorphism, Genetic; D021381:Protein Transport / Q000187:drug effects; D012964:Sodium / Q000378:metabolism; D015222:Sodium Channels / Q000235:genetics* / Q000378:metabolism*
chemical_list: D062554:NAV1.5 Voltage-Gated Sodium Channel; D010455:Peptides; C568320:SCN5A protein, human; D015222:Sodium Channels; D012964:Sodium