@article {336, title = {Multilevel analyses of SCN5A mutations in arrhythmogenic right ventricular dysplasia/cardiomyopathy suggest non-canonical mechanisms for disease pathogenesis.}, journal = {Cardiovasc Res}, volume = {113}, year = {2017}, month = {2017 01}, pages = {102-111}, abstract = {

AIMS: Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy (ARVD/C) is often associated with desmosomal mutations. Recent studies suggest an interaction between the desmosome and sodium channel protein Na1.5. We aimed to determine the prevalence and biophysical properties of mutations in SCN5A (the gene encoding Na1.5) in ARVD/C.

METHODS AND RESULTS: We performed whole-exome sequencing in six ARVD/C patients (33\% male, 38.2 {\textpm} 12.1 years) without a desmosomal mutation. We found a rare missense variant (p.Arg1898His; R1898H) in SCN5A in one patient. We generated induced pluripotent stem cell-derived cardiomyocytes (hIPSC-CMs) from the patient{\textquoteright}s peripheral blood mononuclear cells. The variant was then corrected (R1898R) using Clustered Regularly Interspaced Short Palindromic Repeats/Cas9 technology, allowing us to study the impact of the R1898H substitution in the same cellular background. Whole-cell patch clamping revealed a 36\% reduction in peak sodium current (P = 0.002); super-resolution fluorescence microscopy showed reduced abundance of Na1.5 (P = 0.005) and N-Cadherin (P = 0.026) clusters at the intercalated disc. Subsequently, we sequenced SCN5A in an additional 281 ARVD/C patients (60\% male, 34.8 {\textpm} 13.7 years, 52\% desmosomal mutation-carriers). Five (1.8\%) subjects harboured a putatively pathogenic SCN5A variant (p.Tyr416Cys, p.Leu729del, p.Arg1623Ter, p.Ser1787Asn, and p.Val2016Met). SCN5A variants were associated with prolonged QRS duration (119 {\textpm} 15 vs. 94 {\textpm} 14 ms, P < 0.01) and all SCN5A variant carriers had major structural abnormalities on cardiac imaging.

CONCLUSIONS: Almost 2\% of ARVD/C patients harbour rare SCN5A variants. For one of these variants, we demonstrated reduced sodium current, Na1.5 and N-Cadherin clusters at junctional sites. This suggests that Na1.5 is in a functional complex with adhesion molecules, and reveals potential non-canonical mechanisms by which Na1.5 dysfunction causes cardiomyopathy.

}, keywords = {Adult, Antigens, CD, Arrhythmogenic Right Ventricular Dysplasia, Cadherins, Cell Differentiation, CRISPR-Cas Systems, DNA Mutational Analysis, Electrocardiography, Exome, Female, Gene Editing, Gene Frequency, Genetic Predisposition to Disease, Genome-Wide Association Study, HEK293 Cells, Humans, Induced Pluripotent Stem Cells, Magnetic Resonance Imaging, Male, Membrane Potentials, Middle Aged, Multilevel Analysis, Mutation, Missense, Myocytes, Cardiac, NAV1.5 Voltage-Gated Sodium Channel, Netherlands, Phenotype, Sodium, Transfection, United States, Young Adult}, issn = {1755-3245}, doi = {10.1093/cvr/cvw234}, author = {Te Riele, Anneline S J M and Agullo-Pascual, Esperanza and James, Cynthia A and Leo-Macias, Alejandra and Cerrone, Marina and Zhang, Mingliang and Lin, Xianming and Lin, Bin and Sobreira, Nara L and Amat-Alarcon, Nuria and Marsman, Roos F and Murray, Brittney and Tichnell, Crystal and van der Heijden, Jeroen F and Dooijes, Dennis and van Veen, Toon A B and Tandri, Harikrishna and Fowler, Steven J and Hauer, Richard N W and Tomaselli, Gordon and van den Berg, Maarten P and Taylor, Matthew R G and Brun, Francesca and Sinagra, Gianfranco and Wilde, Arthur A M and Mestroni, Luisa and Bezzina, Connie R and Calkins, Hugh and Peter van Tintelen, J and Bu, Lei and Delmar, Mario and Judge, Daniel P} } @article {261, title = {Mutations in Alstr{\"o}m protein impair terminal differentiation of cardiomyocytes.}, journal = {Nat Commun}, volume = {5}, year = {2014}, month = {2014 Mar 04}, pages = {3416}, abstract = {

Cardiomyocyte cell division and replication in mammals proceed through embryonic development and abruptly decline soon after birth. The process governing cardiomyocyte cell cycle arrest is poorly understood. Here we carry out whole-exome sequencing in an infant with evidence of persistent postnatal cardiomyocyte replication to determine the genetic risk factors. We identify compound heterozygous ALMS1 mutations in the proband, and confirm their presence in her affected sibling, one copy inherited from each heterozygous parent. Next, we recognize homozygous or compound heterozygous truncating mutations in ALMS1 in four other children with high levels of postnatal cardiomyocyte proliferation. Alms1 mRNA knockdown increases multiple markers of proliferation in cardiomyocytes, the percentage of cardiomyocytes in G2/M phases, and the number of cardiomyocytes by 10\% in cultured cells. Homozygous Alms1-mutant mice have increased cardiomyocyte proliferation at 2 weeks postnatal compared with wild-type littermates. We conclude that deficiency of Alstr{\"o}m protein impairs postnatal cardiomyocyte cell cycle arrest.

}, keywords = {Animals, Cell Cycle, Cell Differentiation, Cells, Cultured, DNA-Binding Proteins, Humans, Immunohistochemistry, Mice, Molecular Sequence Data, Mutation, Myocytes, Cardiac, Proteins, Reverse Transcriptase Polymerase Chain Reaction}, issn = {2041-1723}, doi = {10.1038/ncomms4416}, author = {Shenje, Lincoln T and Andersen, Peter and Halushka, Marc K and Lui, Cecillia and Fernandez, Laviel and Collin, Gayle B and Amat-Alarcon, Nuria and Meschino, Wendy and Cutz, Ernest and Chang, Kenneth and Yonescu, Raluca and Batista, Denise A S and Chen, Yan and Chelko, Stephen and Crosson, Jane E and Scheel, Janet and Vricella, Luca and Craig, Brian D and Marosy, Beth A and Mohr, David W and Hetrick, Kurt N and Romm, Jane M and Scott, Alan F and Valle, David and Naggert, J{\"u}rgen K and Kwon, Chulan and Doheny, Kimberly F and Judge, Daniel P} }