Dataset Information

NaV1.6 dysregulation within myocardial T-tubules by D96V calmodulin enhances proarrhythmic sodium and calcium mishandling.

ABSTRACT: Calmodulin (CaM) plays critical roles in cardiomyocytes, regulating Na+ (NaV) and L-type Ca2+ channels (LTCCs). 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 induced a proarrhythmic 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 mice. 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 in vivo. Cardiac-specific NaV1.6 KO protected cD96V mice from increased T-tubular late NaV activity and its arrhythmogenic consequences. In summary, we demonstrate that D96V-CaM promoted arrhythmias by dysregulating LTCCs and NaV1.6 within T-tubules and thereby facilitating aberrant Ca2+ release.

SUBMITTER: Tarasov M

PROVIDER: S-EPMC10065082 | biostudies-literature | 2023 Apr

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

NaV1.6 dysregulation within myocardial T-tubules by D96V calmodulin enhances proarrhythmic sodium and calcium mishandling.

Tarasov Mikhail M Struckman Heather L HL Olgar Yusuf Y Miller Alec A Demirtas Mustafa M Bogdanov Vladimir V Terentyeva Radmila R Soltisz Andrew M AM Meng Xiaolei X Min Dennison D Sakuta Galina G Dunlap Izabella I Duran Antonia D AD Foster Mark P MP Davis Jonathan P JP Terentyev Dmitry D Györke Sándor S Veeraraghavan Rengasayee R Radwański Przemysław B PB

The Journal of clinical investigation 20230403 7

Calmodulin (CaM) plays critical roles in cardiomyocytes, regulating Na+ (NaV) and L-type Ca2+ channels (LTCCs). 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 wi ...[more]

PMID: 36821382

Similar Datasets

Project description:Impairments in neural lysosomal- and autophagic-mediated degradation of cellular debris contribute to neuritic dystrophy and synaptic loss. While these are well-characterized features of neurodegenerative disorders such as Alzheimer's disease (AD), the upstream cellular processes driving deficits in pathogenic protein mishandling are less understood. Using a series of fluorescent biosensors and optical imaging in model cells, AD mouse models and human neurons derived from AD patients, we reveal a previously undescribed cellular signaling cascade underlying protein mishandling mediated by intracellular calcium dysregulation, an early component of AD pathogenesis. Increased Ca2+ release via the endoplasmic reticulum (ER)-resident ryanodine receptor (RyR) is associated with reduced expression of the lysosome proton pump vacuolar-ATPase (vATPase) subunits (V1B2 and V0a1), resulting in lysosome deacidification and disrupted proteolytic activity in AD mouse models and human-induced neurons (HiN). As a result of impaired lysosome digestive capacity, mature autophagosomes with hyperphosphorylated tau accumulated in AD murine neurons and AD HiN, exacerbating proteinopathy. Normalizing AD-associated aberrant RyR-Ca2+ signaling with the negative allosteric modulator, dantrolene (Ryanodex), restored vATPase levels, lysosomal acidification and proteolytic activity, and autophagic clearance of intracellular protein aggregates in AD neurons. These results highlight that prior to overt AD histopathology or cognitive deficits, aberrant upstream Ca2+ signaling disrupts lysosomal acidification and contributes to pathological accumulation of intracellular protein aggregates. Importantly, this is demonstrated in animal models of AD, and in human iPSC-derived neurons from AD patients. Furthermore, pharmacological suppression of RyR-Ca2+ release rescued proteolytic function, revealing a target for therapeutic intervention that has demonstrated effects in clinically-relevant assays.

Project description:Ischaemic heart disease (IHD) remains a major cause of death and morbidity. Klotho is a well-known anti-ageing factor with relevant cardioprotective actions, at least when renal dysfunction is present, but its actions are much less known when renal function is preserved. This study investigated Klotho as a biomarker and potential novel treatment of IHD-associated complications after myocardial infarction (MI) under preserved renal function. Association between circulating Klotho levels and cardiac injury was investigated in patients after ST-elevation MI (STEMI). Biochemical, in vivo and in vitro cardiac function and histological and molecular studies were performed to determine the effect of recombinant Klotho in the failing hearts of mice after MI. We demonstrated that STEMI patients showed lower systemic Klotho levels, with the lowest Klotho tertile in those patients with higher N-terminal pro B-type natriuretic peptide (NT-proBNP) levels. Mice also showed a decrease in systemic Klotho levels after MI induction. Furthermore, recombinant Klotho administration in mice reduced infarct area and attenuated cardiac hypertrophy and fibrosis. We also demonstrated that Klotho treatment prevented reduction in ejection fraction and MI-related ECG changes, including prolonged QRS, JT, QTc, and TpeakTend intervals and premature ventricular contractions. In adult mouse cardiomyocytes, Klotho treatment restricted systolic calcium (Ca2+) release and cell shortening disturbances after MI. Klotho prevented increased diastolic Ca2+ leak and pro-arrhythmogenic events in PMI mice by blocking activation of the Ca2+/calmodulin-dependent kinase type II (CaMKII) pathway, preventing ryanodine receptor type 2 (RyR2) hyperphosphorylation. In conclusion, Klotho supplementation protected against functional and structural cardiac remodelling and ameliorated ventricular arrhythmic events by preventing intracardiomyocyte Ca2+ mishandling in mice following MI. These data uncover a new cardioprotective role of Klotho, emerging as a biomarker of ventricular injury and potential treatment for patients after MI. © 2025 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Dataset Information

NaV1.6 dysregulation within myocardial T-tubules by D96V calmodulin enhances proarrhythmic sodium and calcium mishandling.

Publications

NaV1.6 dysregulation within myocardial T-tubules by D96V calmodulin enhances proarrhythmic sodium and calcium mishandling.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets