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Updated: Dec 8, 2025
Isolation and Physiological Analysis of Mouse Cardiomyocytes
Published on: September 7, 2014
Huntingtin protein maintains balanced energetics in mouse cardiomyocytes
Marta Tomczyk1, Talita Glaser2, Henning Ulrich2
1Department of Biochemistry, Medical University of Gdansk, Gdansk, Poland.
Insights
Huntingtin protein (HTT) is vital for heart cell energy and nucleotide metabolism. Loss of HTT function in cardiomyocytes impairs ATP and NAD+ levels, contributing to Huntington's disease energy deficits.
Area of Science:
- Cardiovascular Biology
- Molecular Metabolism
- Neurodegenerative Disease Research
Background:
- Huntingtin (HTT) protein is essential for development, and its mutation causes Huntington's disease (HD).
- Cardiovascular pathologies are increasingly recognized in HD patients, suggesting a role for HTT beyond the nervous system.
- The specific function of HTT in cardiac cellular energy and nucleotide metabolism remains largely unexplored.
Purpose of the Study:
- To investigate the role of huntingtin protein in the cellular energy and nucleotide metabolism of cardiomyocytes.
- To determine the impact of HTT deficiency on key metabolic indicators within cardiac cells.
Main Methods:
- Utilized CRISPR-Cas9 technology to generate HTT knockout (KO) mouse embryonic stem cells (ESCs).
- Differentiated wild-type (WT) and HTT KO ESCs into cardiomyocytes for comparative analysis.
- Employed High-Performance Liquid Chromatography (HPLC) to quantify intracellular ATP, ADP, NAD+, and nucleotide catabolites.
Main Results:
- HTT null cardiomyocytes exhibited significantly reduced intracellular ATP and NAD+ concentrations compared to control groups.
- A diminished total purines pool and lower inosine monophosphate (IMP) levels were observed in the cellular medium of HTT KO cardiomyocytes.
- These findings indicate a critical role for HTT in maintaining cellular energy homeostasis and nucleotide turnover.
Conclusions:
- Huntingtin protein is crucial for maintaining cellular energy balance and nucleotide metabolism in cardiomyocytes.
- The observed metabolic dysfunction in Huntington's disease may stem from both the gain of toxic function by mutant HTT and the loss of normal HTT function.
- This research highlights potential therapeutic targets within cardiac energy metabolism for HD management.
Abstract:
Huntingtin (HTT) is a multifunctional protein crucial for proper embryogenesis and nervous system development. Mutation of a single allele in gene coded this protein results in the Huntington׳s disease (HD). There is growing evidence of cardiovascular system pathologies coexisting with the neurological symptoms in HD patients. Thus, this study aims to establish the role of huntingtin protein in cardiomyocytes cellular energy and nucleotides metabolism. We used HTT KO mice embryonic stem cells (ESC) obtained with CRISPR method, wild type mice ESC treated by CRISPR with Scramble control sequence (SCR) as well as wild type (WT) mice ESC and differentiate it into cardiomyocytes. Analysis of intracellular concentration of ATP, ADP, and NAD+, as well as nucleotide catabolites were performed with HPLC. We noted that HTT null cardiomyocytes showed diminished intracellular ATP (4.9 ± 0.5; 6.7 ± 0.4 nmol/mg protein HTT KO vs. SCR) and NAD+ (0.9 ± 0.1; 1.6 ± 0.1 nmol/mg HTT KO vs. SCR). We noted also reduced cellular medium concentration of total purines pool (17.1 ± 1.7; 24.7 ± 2.7 nmol/ml HTT KO vs. SCR) as well as IMP concentration (7.7 ± 0.6; 10.2 ± 0.4 nmol/ml HTT KO vs. SCR). This study indicates that HTT plays an important role in cellular energy balance as well as in nucleotide metabolism in cardiomyocytes. Furthermore, our findings underline that the deterioration in energy metabolism observed in HD may be caused not only by cellular mutant HTT accumulation but also by the loss of HTT function.
