Key result
CRISPRi targeting CALM2 halves minimum capture cycle length in engineered cardiac tissue.
Why the study?
Calmodulinopathies cause life-threatening arrhythmias by disrupting calcium channel inactivation, and effective genome-editing correction in structured cardiac tissues remains challenging.
Does lentiviral CRISPRi targeting CALM2 correct electrophysiological, mechanical, and structural defects in human iPSC-derived 2D and 3D cardiac tissue models of D130G-CALM2 long QT syndrome?
Does lentiviral CRISPRi targeting CALM2 correct electrophysiological, mechanical, and structural defects in human iPSC-derived 2D and 3D cardiac tissue models of D130G-CALM2 long QT syndrome?
CRISPRi-mediated suppression of mutant CALM2 in intact 3D human engineered cardiac tissues rescues long QT syndrome electrophysiological and mechanical dysfunction and promotes early structural maturation despite incomplete cellular transduction.
Answers are grounded in this paper and cite their sources.
CRISPRi of CALM2 rescues electrical and mechanical defects in hiPSC LQTS models; leaves open in vivo validation and clinical translation.
Background Calmodulinopathies, caused by mutations such as D130G-CALM2, produce life-threatening arrhythmias by disrupting calcium-dependent inactivation of cardiac calcium channels, resulting in prolonged and unstable repolarization. Effective correction in structured cardiac tissues using genome editing remains challenging. Objective To test CRISPR interference (CRISPRi)-mediated correction of electrical, mechanical, and structural defects in hiPSC-derived cardiac models of calmodulinopathic long QT syndrome (LQTS). Methods 2D monolayers, 3D cardiospheres, and aligned cardiac microtissues were generated from D130G-CALM2 hiPSC-derived cardiomyocytes and treated with lentiviral CRISPRi targeting CALM2. Phenotypic rescue was assessed by optical mapping, force measurement, qPCR, and electron microscopy. Results CRISPRi selectively reduced CALM2 expression, corrected prolonged action potentials, eliminated electrical and mechanical alternans, improved pacing tolerance, enhanced force generation, and promoted features consistent with early structural maturation, including membrane invaginations suggestive of T-tubule-like development. Conclusion CRISPRi-mediated electrical stabilization rescues electrophysiological dysfunction, enhancing mechanical performance and promoting features consistent with early structural maturation, highlighting its potential for therapeutic correction of congenital arrhythmias. These findings establish patient-specific hiPSC-derived engineered cardiac tissues as a translational stem cell platform for correcting inherited electrophysiological disease and promoting early functional and structural maturation in cardiovascular tissue models.
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Huang et al. (2026) studied Calmodulinopathic long QT syndrome (LQTS) caused by D130G-CALM2 mutation. Lentiviral CRISPR interference (CRISPRi) targeting CALM2 (dCas9-KRAB and gRNA-CALM2) vs. Uncorrected controls transduced with Cas9-KRAB and empty backbone control virus (PKLV) was evaluated on Minimum pacing cycle length (CL) required to maintain 1:1 capture in 3D cardiac microtissues (CMTs) (p=0.014).
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