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Measuring Fast Calcium Fluxes in Cardiomyocytes
Published on: November 29, 2011
Novel therapeutic cav1.3-C-terminus normalizes L-type calcium current and ejection fraction in ischemia-induced
Michael Cupelli1, Vamsi Krishna Murthy Ginjupalli1, Ujala Srivastava1
1Cardiovascular Research Program, VA New York Harbor Healthcare System, New York, NY, USA.
Insights
A novel therapy using the Cav1.3-C-terminus restored ejection fraction in heart failure mice. This treatment also improved cardiac function and reduced arrhythmias, offering a potential new therapeutic approach.
Area of Science:
- Cardiovascular Biology
- Molecular Cardiology
- Gene Therapy
Background:
- Heart failure (HF) affects millions, with suboptimal outcomes despite current therapies.
- Cav1.3 L-type calcium channels are re-expressed in failing ventricles.
- The Cav1.3-C-terminus acts as a transcription factor in heart failure.
Purpose of the Study:
- To investigate the therapeutic potential of the Cav1.3-C-terminus to restore ejection fraction in heart failure.
- To leverage the auto-enhancer properties of the Cav1.3-C-terminus for HF treatment.
Main Methods:
- Established heart failure in wild-type and Cav1.3-heterozygous-knockout mice via LAD ligation.
- Administered adeno-associated virus serotype 9 (AAV9) carrying the Cav1.3-C-terminus or a vehicle control.
- Utilized echocardiography, histology, biochemistry, patch-clamp, optical mapping, and RNA-sequencing for analysis.
Main Results:
- AAV9-Cav1.3-C-terminus treatment normalized left ventricular ejection fraction in HF mice.
- Treatment led to resistance against inducible arrhythmias and improved L-type calcium current.
- Upregulation of CACN1D (encoding Cav1.3) was observed in the treated group.
Conclusions:
- AAV9-Cav1.3-C-terminus treatment effectively improved cardiac function and reduced arrhythmias in a mouse model of HF.
- The therapy likely acts through transcriptional upregulation of Cav1.3, optimizing calcium current.
- This approach represents a promising novel therapeutic strategy for heart failure.
Introduction:
Heart failure (HF) affects approximately 6.7 million Americans and rising. Despite multi-modality therapy, patient outcomes remain suboptimal. It has been recently shown that Cav1.3 L-type calcium channels are re-expressed in ischemic failing human ventricles, and the Cav1.3-C-terminus is cleaved and acts as a transcription factor. Here, we leveraged the Cav1.3-C-terminus's auto-enhancer properties as a novel therapy to restore ejection fraction (EF) in HF.
Methods:
HF was established in wild-type (WT) and Cav1.3-heterozygous-knockout (Cav1.3+/-) mice 15-days post-ligation of the left-anterior-descending coronary artery (LAD). Treatment groups received adeno-associated-virus-serotype-9(AAV9)-Cav1.3-C-terminus or vehicle. Echocardiography, histology, biochemistry, patch-clamp, optical mapping, and RNA-seq were performed.
Results:
At day 15 post-LAD-ligation, WT-HF mice displayed fibrosis, impaired wall motion, increased left ventricular diameter in diastole and systole, and decreased left ventricular EF and fractional shortening vs. WT-Sham. Cav1.3 mRNA/protein levels increased in WT-HF mice vs. WT-Sham. At day 30 post-AAV9-Cav1.3-C-terminus-treatment, WT-Sham and Cav1.3+/-HF mice showed increased L-type calcium current vs. vehicle. AAV9-Cav1.3-C-terminus-treated WT-HF mice returned to sinus rhythm after premature stimulation while vehicle-treated WT-HF mice showed arrhythmias such as bigeminy and triplets. Left ventricular EF normalized in both WT-HF and Cav1.3+/-HF mice post-AAV9-Cav1.3-C-terminus-treatment. CACN1D, encoding Cav1.3, was upregulated 1.9-Log2-fold in the AAV9-Cav1.3-C-terminus-treated group vs. vehicle.
Conclusions:
AAV9-Cav1.3-C-terminus-treatment of mice with HF resulted in resistance to inducible arrhythmia and normalization of left ventricular EF, likely via a transcriptional upregulation of Cav1.3 and the resulting optimal increase in L-type calcium current. Therefore, AAV9-Cav1.3-C-terminus may be leveraged as a novel therapeutic approach to improve cardiac function.

