Data from: NaV1.6 dysregulation within myocardial T-tubules by D96V calmodulin enhances proarrhythmic sodium and calcium mishandling
Data files
May 29, 2023 version files 117.65 GB
Abstract
Calmodulin (CaM) plays critical roles in cardiomyocytes, regulating Na+ (NaV) and L-type Ca2+ channels (LTCC). LTCC dysregulation by mutant CaMs has been implicated in action potential duration (APD) prolongation and arrhythmogenic long QT (LQT) syndrome. Intriguingly, D96V-CaM prolongs APD more than other LQT-associated CaMs despite inducing comparable levels of LTCC dysfunction, suggesting dysregulation of other depolarizing channels. Here, we provide evidence implicating NaV dysregulation within transverse (T)-tubules in D96V-CaM-associated arrhythmias. D96V-CaM induces pro-arrhythmic late Na+ current (INa) by impairing inactivation of NaV1.6, but not the predominant cardiac NaV isoform, NaV1.5. We investigated arrhythmia mechanisms using mice with cardiac-specific expression of D96V-CaM (cD96V). Super-resolution microscopy revealed close proximity of NaV1.6 and RyR2 within T-tubules. NaV1.6 density within these regions increased in cD96V relative to WT. Consistent with NaV1.6 dysregulation by D96V-CaM in these regions, we observed increased late NaV activity in T-tubules. The resulting late INa promoted aberrant Ca2+ release and prolonged APD in myocytes, leading to LQT and ventricular tachycardia (VT) in vivo. Cardiac-specific NaV1.6 knockout protected cD96V mice from increased T-tubular late NaV activity, and its arrhythmogenic consequences. In summary, we demonstrate that D96V-CaM promotes arrhythmias by dysregulating LTCC and NaV1.6 within T-tubules and thereby, facilitating aberrant Ca2+ release.
Usage notes
STORM: Zip file containing single molecule localization data from STORM
AP and Ca records: Zip file containing action potential (AP) and calcium imaging (Ca2+) records
4,9 ahTTX IC50: Zip file containing patch clamp records from dose-response (IC50) experiments for 4,9ah TTX blockade of human and mouse NaV1.5 and NaV1.6
AIP AP in cD96V: Zip file containing action potential (AP) records from cD96V myocytes incubated in Autocamtide-2-related inhibitory peptide, myristoylated (AIP)
Ca Sparks: Zip file containing records of Ca2+ sparks
Cardiac myocytes and CHO whole cell D96V-CaM INa: Zip file containing whole cell sodium current (INa) records from mouse cardiac myocytes and CHO cells dialyzed with WT-CaM and D96V-CaM
ECG: Zip file containing ECG data
Fibrosis: Zip file containing fibrosis assessment data
ICa: Zip file containing whole cell patch clamp records of Ca2+ current (ICa) in cD96V and cD96V x cNaV1.6KO myocytes
IPSC INa: Zip file containing whole cell patch clamp records of Na+ currents (INa) in human induced pluripotent stem cells derived cardiac myocytes (hIPSC-CMs) dialyzed with WT-CaM or D96V-CaM
ITC: Zip file containing isothermal titration calorimetry (ITC) data
MRI Data: Zip file containing magnetic resonance imaging (MRI) data
WB: Zip file containing western blot (WB) data
Confocal Data: Zip file containing confocal microscopy data is split into 9 volumes (001 – 009)
Ca waves and SR load: Zip file containing calcium imaging data is split into 4 volumes (001 – 004)
Smart patch: Zip file containing scanning ion conductance microscopy guided ‘smart’ patch clamp data