Recessive cardiac phenotypes in induced pluripotent stem cell models of Jervell and Lange-Nielsen syndrome: Disease mechanisms and pharmacological rescue

Abstract

Jervell and Lange-Nielsen syndrome (JLNS) is one of the most severe life-threatening cardiac arrhythmias. Patients display delayed cardiac repolarization, associated high risk of sudden death due to ventricular tachycardia, and congenital bilateral deafness. In contrast to the autosomal dominant forms of long QT syndrome, JLNS is a recessive trait, resulting from homozygous (or compound heterozygous) mutations in KCNQ1 or KCNE1. These genes encode the α and β subunits, respectively, of the ion channel conducting the slow component of the delayed rectifier K + current, I Ks . We used complementary approaches, reprogramming patient cells and genetic engineering, to generate human induced pluripotent stem cell (hiPSC) models of JLNS, covering splice site (c.478-2A>T) and missense (c.1781G>A) mutations, the two major classes of JLNS-causing defects in KCNQ1. Electrophysiological comparison of hiPSC-derived cardiomyocytes (CMs) from homozygous JLNS, heterozygous, and wild-type lines recapitulated the typical and severe features of JLNS, including pronounced action and field potential prolongation and severe reduction or absence of I Ks . We show that this phenotype had distinct underlying molecular mechanisms in the two sets of cell lines: the previously unidentified c.478-2A>T mutation was amorphic and gave rise to a strictly recessive phenotype in JLNS-CMs, whereas the missense c.1781G>A lesion caused a gene dosage-dependent channel reduction at the cell membrane. Moreover, adrenergic stimulation caused action potential prolongation specifically in JLNS-CMs. Furthermore, sensitivity to proarrhythmic drugs was strongly enhanced in JLNSCMs but could be pharmacologically corrected. Our data provide mechanistic insight into distinct classes of JLNS-causing mutations and demonstrate the potential of hiPSC-CMs in drug evaluation.Jervell and Lange-Nielsen syndrome | long QT syndrome | human induced pluripotent stem cells | disease modeling | KCNQ1

Integrating cardiomyocytes from human pluripotent stem cells in safety pharmacology: has the time come?

“…In addition, hiPSC‐CMs are also being used as model systems to test the effect of both known and novel drugs on cardiac channelopathies (Matsa et al , 2011; Zhang et al , 2012; Bellin et al , 2013; Di Pasquale et al , 2013; Zhang et al , 2014), with suppression of pathological pro‐arrhythmic potential and restoration of altered AP duration (APD) being two main endpoints. Clinical evidence has shown that pharmacological treatments can be of more benefit when properly calibrated in a disease‐specific or even mutation‐specific manner (Nebert and Vesell, 2006; Cavallari, 2012; Amin and Wilde, 2016; Itoh et al , 2016; Martiniano et al , 2016).…”

“…The green area defines the normal QT interval range for humans. Data are shown as mean ± SD: 1, (Malan et al , 2016); 2, (Rocchetti/Sala et al , unpublished); 3, (Zhang et al , 2014); 4, (Zhang et al , 2014); 5, (Davis et al , 2012); 6, (Rocchetti/Sala et al , unpublished); 7, (Bellin et al , 2013); 8, (Sala et al , 2016); 9, (Bizy et al , 2013); 10, (Ma et al , 2013); 11, (Ma et al , 2015); 12, (Ma et al , 2015); 13, (Gibson et al , 2014a); 14, (Itzhaki et al , 2011); 15, (Gibson et al , 2014c); 16, (Lu et al , 2014); 17, (Gibson et al , 2014b); 18, (Mehta et al , 2014). (B) and (C) Composition of extracellular buffers (B) and pipette solutions (C) for current clamp experiments.…”

Readthrough-Promoting Drugs Gentamicin and PTC124 Fail to Rescue Na v 1.5 Function of Human-Induced Pluripotent Stem Cell–Derived Cardiomyocytes Carrying Nonsense Mutations in the Sodium Channel Gene SCN5A

“…Reprogramming of the skin fibroblasts was performed as described previously. 17 In brief, skin fibroblasts derived from a donated biopsy were infected with Sendai virus encoding OCT4, SOX2, KLF4, and MYC and cultured on mouse embryonic feeder cells until hiPSC colonies appeared and could be picked for further expansion and characterization for pluripotency in culture and cryopreserved. A second, non-sex matched, control hiPSC line was generated previously and characterized in detail.…”

“…A second, non-sex matched, control hiPSC line was generated previously and characterized in detail. 17 …”

Inherited heart disease – what can we expect from the second decade of human iPS cell research?

“…the slow I Ks , and the rapid I Kr components of the delayed rectifier potassium currents, the sodium current I Na , and the L‐type calcium current I CaL ) varying widely even among wild‐type control hiPSC‐CMs 55, 56. Most notably, very different levels of I Ks have been described (ranging from ~ 0.3 to ~ 2.5 pA/pF 5, 57), variable observation leading to controversial conclusions: on the one hand, I Ks recapitulates physiological behaviour in playing a major role when repolarisation reserve is attenuated 58, 59; on the other, it seems to contribute to repolarisation in hiPSC‐CMs even in the absence of sympathetic stimulation 5, 36, 60, 61. The immature phenotype of all stem cell derivatives including hiPSC‐CMs is probably the reason for this variability but, independent of the cause, it is a limitation to extrapolating results obtained using hiPSC‐CMs to native – healthy and diseased – adult human CMs as discussed below.…”