GO:0003300 cardiac muscle hypertrophy: Growth Signaling, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0003300 cardiac muscle hypertrophy is defined as the enlargement or overgrowth of all or part of the heart muscle due to an increase in the size of cardiac muscle cells without cell division.
• Cardiac muscle hypertrophy is a fundamental adaptive response of the heart to increased workload, neurohumoral signals, and mechanical stress, and it is distinct from hyperplasia because it does not involve cardiomyocyte proliferation.
• At the molecular level, hypertrophy involves reactivation of fetal gene programs, increased protein synthesis, sarcomeric remodeling, and changes in calcium handling and metabolism.
• Mechanotransduction, noncoding RNAs, and telomerase activity are among the diverse regulators that modulate cardiac muscle hypertrophy.
• Cardiac muscle hypertrophy is a central feature of hypertensive heart disease, hypertrophic cardiomyopathy, and heart failure, and it can also be studied in metabolic cardiomyopathies.
• CRISPR-based models (knockout, point mutation, knock-in, overexpression) enable causal testing of hypertrophy-related genes in cardiomyocytes and animal models.
Description
Cardiac muscle hypertrophy (GO:0003300) is the process by which the heart muscle enlarges due to an increase in the size of individual cardiac muscle cells, rather than an increase in cell number. This biological process is a hallmark of the heart's response to chronic pressure or volume overload, such as that caused by hypertension, and it is a major determinant of cardiac morbidity and mortality. Unlike developmental growth, pathological cardiac hypertrophy is often accompanied by reactivation of fetal gene expression, metabolic remodeling, and fibrosis, which can ultimately lead to heart failure. Understanding the molecular and cellular mechanisms of cardiac muscle hypertrophy is therefore critical for identifying therapeutic targets and biomarkers. Research in this field spans from basic studies of cardiomyocyte biology to translational investigations in animal models and human patients. The process is regulated by a complex interplay of mechanical stretch, neurohumoral factors, and intracellular signaling pathways that converge on the nucleus to reprogram gene expression. Noncoding RNAs have emerged as key regulators of cardiac muscle mass, adding another layer of complexity to the hypertrophic response. This article provides a comprehensive overview of GO:0003300, including its definition, underlying mechanisms, key genes, disease relevance, and state-of-the-art research methods.
cardiac muscle hypertrophy At A Glance
| GO ID | GO:0003300 |
|---|---|
| GO term | cardiac muscle hypertrophy |
| Ontology | biological_process |
| Synonym | none |
| Major function | Enlargement of heart muscle due to increased cardiac muscle cell size without cell division |
| Related processes | Cardiac muscle cell differentiation, mechanotransduction, fetal gene program reactivation |
| Disease relevance | Hypertensive heart disease, hypertrophic cardiomyopathy, heart failure, metabolic cardiomyopathies |
| Key regulators | Mechanical stretch, neurohumoral factors, noncoding RNAs, telomerase, metabolic signals |
What Is GO:0003300?
According to the Gene Ontology, cardiac muscle hypertrophy (GO:0003300) is the enlargement or overgrowth of all or part of the heart muscle due to an increase in the size of cardiac muscle cells without cell division. This definition distinguishes hypertrophy from hyperplasia, which involves cell proliferation. The process is characterized by an increase in cardiomyocyte volume, enhanced protein synthesis, and sarcomeric organization, often as an adaptive response to increased workload or pathological stimuli.
Why Is cardiac muscle hypertrophy Important in Cell Biology?
Cardiac muscle hypertrophy is a central adaptive and maladaptive response of the heart to stress, and it is a major risk factor for heart failure, arrhythmias, and sudden cardiac death. Understanding its molecular basis is essential for developing therapies that can prevent or reverse pathological cardiac remodeling. Moreover, the process serves as a paradigm for studying how cells integrate mechanical and biochemical signals to alter gene expression and cell size.
• It is a key compensatory mechanism in hypertension and valvular heart disease.
• It is a defining feature of hypertrophic cardiomyopathy and other genetic cardiomyopathies.
• It involves reactivation of fetal gene programs, providing insights into developmental biology.
• Noncoding RNAs regulate cardiac muscle mass and offer novel therapeutic targets.
• Telomerase activity can promote cardiac muscle cell hypertrophy and survival.
• Mechanotransduction pathways are critical for sensing and responding to mechanical load.
• Metabolic cardiomyopathies often present with hypertrophy, linking metabolism to cardiac growth.
• There may be an upper limit to cardiac muscle hypertrophy, which is relevant for understanding heart failure.
• It is a major focus for drug discovery and gene therapy approaches.
• CRISPR screening can identify novel regulators of cardiomyocyte size.
What Happens During cardiac muscle hypertrophy?
Initiation by Mechanical and Neurohumoral Signals
In simple terms: The heart senses increased workload and stress hormones, which trigger a growth response.
Cardiac muscle hypertrophy is initiated by mechanical stretch and neurohumoral factors such as angiotensin II and catecholamines, which activate membrane receptors and mechanosensors. These signals converge on intracellular kinases, including MAPKs and PI3K/Akt, leading to transcriptional changes. In hypertension, increased afterload is a primary trigger for hypertrophic growth.
Reactivation of Fetal Gene Program
In simple terms: The heart switches back to a gene expression pattern similar to that of the developing heart.
A hallmark of cardiac hypertrophy is the re-expression of fetal genes, such as atrial natriuretic factor (NPPA) and skeletal alpha-actin, which are normally silenced in the adult heart. This reprogramming is mediated by transcription factors like GATA4, MEF2, and NFAT, and contributes to altered contractility and metabolism.
Increased Protein Synthesis and Sarcomeric Remodeling
In simple terms: Heart muscle cells build more contractile proteins, making each cell larger.
Hypertrophic growth requires a substantial increase in protein synthesis and the addition of sarcomeres in parallel or in series, leading to concentric or eccentric hypertrophy. This involves mTOR signaling, ribosome biogenesis, and changes in calcium handling. The enlargement of cardiomyocytes without division is a defining feature of GO:0003300.
Metabolic and Noncoding RNA Regulation
In simple terms: The heart changes its energy use and small RNA molecules fine-tune the growth response.
Metabolic shifts, such as increased glucose uptake and altered fatty acid oxidation, accompany hypertrophy and can be caused by metabolic cardiomyopathies. Noncoding RNAs, including microRNAs and long noncoding RNAs, regulate cardiac muscle mass by targeting hypertrophic signaling pathways. Telomerase reverse transcriptase (TERT) has also been shown to promote cardiac muscle cell hypertrophy and survival.
Transition to Failure and Upper Limits
In simple terms: If the stress continues, the heart may reach a limit and start to fail.
While hypertrophy is initially compensatory, sustained stress can lead to maladaptive remodeling, fibrosis, and heart failure. There is evidence for a potential upper limit to cardiac muscle hypertrophy, beyond which further growth is detrimental. Understanding these transitions is crucial for therapeutic intervention.
Key Genes Involved in GO:0003300 cardiac muscle hypertrophy
The following genes and proteins are experimentally implicated in cardiac muscle hypertrophy and related signaling pathways.
| Gene | Major Role | Research Relevance |
|---|---|---|
| NPPA | Fetal gene reactivation; natriuretic peptide | Biomarker of hypertrophy; target for gene expression studies |
| NPPB | Fetal gene reactivation; natriuretic peptide | Clinical biomarker in heart failure |
| MYH7 | Sarcomeric beta-myosin heavy chain | Mutations cause hypertrophic cardiomyopathy |
| ACTA1 | Skeletal alpha-actin; fetal isoform | Re-expressed in hypertrophy |
| TERT | Telomerase reverse transcriptase | Promotes hypertrophy and survival |
| MTOR | mTOR kinase; protein synthesis | Central regulator of hypertrophic growth |
| AKT1 | PI3K/Akt signaling | Promotes cardiomyocyte growth and survival |
| MAPK1 | MAPK signaling | Mediates mechanical stress responses |
| GATA4 | Transcription factor | Regulates fetal gene program |
| MEF2C | Transcription factor | Cooperates with GATA4 in hypertrophy |
| NFATC1 | Calcineurin/NFAT signaling | Induces hypertrophic gene expression |
| CAMK2D | Calcium/calmodulin-dependent kinase | Modulates hypertrophy and calcium handling |
| PRKAA1 | AMPK catalytic subunit | Metabolic sensor; regulates growth |
| PPARGC1A | PGC-1alpha; mitochondrial biogenesis | Metabolic remodeling in hypertrophy |
| MIR133A1 | MicroRNA-133a | Suppresses hypertrophy; regulates cardiac mass |
| MIR208A | MicroRNA-208a | Regulates myosin heavy chain and hypertrophy |
| MALAT1 | Long noncoding RNA | Modulates cardiac hypertrophy |
| SIRT1 | NAD-dependent deacetylase | Regulates stress response and hypertrophy |
How Is cardiac muscle hypertrophy Regulated?
Cardiac muscle hypertrophy is regulated by a complex network of signaling pathways, including the PI3K/Akt/mTOR axis, MAPK cascades, calcineurin/NFAT, and AMPK. Mechanical stretch and neurohumoral factors activate these pathways, leading to transcriptional and translational changes. Noncoding RNAs, such as microRNAs and long noncoding RNAs, provide an additional layer of post-transcriptional regulation. Telomerase reverse transcriptase (TERT) has been shown to promote hypertrophy and survival, linking telomere maintenance to cardiac growth. Metabolic signals, including insulin and AMPK, also modulate hypertrophic responses.
cardiac muscle hypertrophy and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| MYH7 | Hypertrophic cardiomyopathy | Knock-in mouse model with patient mutation |
| NPPA | Heart failure biomarker | Overexpression in cardiomyocytes |
| TERT | Cardiac hypertrophy and survival | Knockout and overexpression models |
| MIR133A1 | Cardiac hypertrophy regulation | Knockout and transgenic overexpression |
| MTOR | Hypertrophy signaling | Conditional knockout in heart |
Hypertensive Heart Disease
Chronic hypertension imposes increased afterload on the left ventricle, leading to compensatory cardiac muscle hypertrophy. While initially adaptive, this hypertrophy often progresses to heart failure and is associated with increased cardiovascular mortality. The process involves neurohumoral activation and mechanical stretch, making it a target for antihypertensive therapies.
Hypertrophic Cardiomyopathy
Hypertrophic cardiomyopathy (HCM) is a genetic disorder characterized by unexplained cardiac muscle hypertrophy, often caused by mutations in sarcomeric genes such as MYH7. HCM can lead to arrhythmias and sudden cardiac death. Studying the molecular mechanisms of hypertrophy in HCM provides insights into both genetic and acquired forms of cardiac growth.
Metabolic Cardiomyopathies
Metabolic cardiomyopathies, including those caused by mitochondrial defects or storage diseases, frequently present with cardiac hypertrophy. These conditions highlight the interplay between metabolic pathways and hypertrophic growth. Research into metabolic cardiomyopathies can reveal how altered energy metabolism drives cardiac remodeling.
Heart Failure
Pathological cardiac hypertrophy is a major risk factor for heart failure. As hypertrophy progresses, the heart may transition from compensated to decompensated failure, with fibrosis and reduced contractility. Understanding the signaling pathways that drive this transition is critical for developing therapies to prevent heart failure.
From cardiac muscle hypertrophy-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Is gene X required for cardiac hypertrophy? | Knockout mouse or CRISPR knockout in cardiomyocytes |
| Does a specific point mutation cause hypertrophic cardiomyopathy? | Point-mutation knock-in mouse or iPSC-derived cardiomyocytes |
| Does overexpression of gene Y induce hypertrophy? | Transgenic overexpression or viral delivery in vivo |
| How does a tagged protein localize during hypertrophy? | Tagged knock-in (e.g., GFP) in cardiomyocytes |
| What are the transcriptomic changes during hypertrophy? | RNA-seq in knockout vs wild-type models |
| Can a noncoding RNA be targeted to reduce hypertrophy? | Antagomir or CRISPR interference in animal models |
How to Study the cardiac muscle hypertrophy Process
| Method | What It Measures | Typical Application |
|---|---|---|
| RNA-seq | Transcriptome changes | Identify fetal gene reactivation |
| ChIP-seq | Transcription factor binding | Map GATA4/MEF2 binding sites |
| Proteomics | Protein abundance and modifications | Quantify sarcomeric proteins |
| Echocardiography | Wall thickness and function | Assess hypertrophy in vivo |
| Confocal microscopy | Cardiomyocyte size and sarcomere structure | Measure hypertrophy in vitro |
| CRISPR screen | Gene function at scale | Discover novel hypertrophy regulators |
| Metabolomics | Metabolic intermediates | Assess metabolic remodeling |
Transcriptomic and Epigenomic Profiling
RNA-seq and ChIP-seq are used to identify changes in gene expression and chromatin state during cardiac hypertrophy. These methods reveal reactivation of fetal genes and regulatory networks. Single-cell RNA-seq can dissect heterogeneity among cardiomyocytes and non-myocytes.
Proteomic and Metabolic Analyses
Mass spectrometry-based proteomics quantifies changes in sarcomeric and metabolic proteins. Metabolomics and Seahorse assays assess shifts in energy metabolism, such as increased glycolysis, which are characteristic of hypertrophic hearts.
Imaging and Functional Assessment
Echocardiography and cardiac MRI measure wall thickness and function in animal models and patients. Confocal microscopy of isolated cardiomyocytes assesses cell size and sarcomere organization. Calcium imaging evaluates contractile function.
CRISPR Screening and Functional Genomics
Genome-wide CRISPR knockout or activation screens in cardiomyocytes can identify novel regulators of cell size and hypertrophic gene expression. These screens are powerful for discovering drug targets and validating candidate genes.
How CRISPR Can Be Used to Study GO:0003300 cardiac muscle hypertrophy
Knockout
CRISPR knockout of candidate genes in cardiomyocytes or mouse models can determine whether a gene is necessary for cardiac hypertrophy. For example, knocking out Mtor or Akt1 blunts hypertrophic growth in response to pressure overload. Knockout studies of TERT have revealed its role in cardiac muscle cell proliferation, hypertrophy, and survival.
Point Mutation
Introducing patient-specific point mutations (e.g., in MYH7) using CRISPR base editing or homology-directed repair creates models of hypertrophic cardiomyopathy. These models help dissect the molecular mechanisms by which sarcomeric mutations cause hypertrophy.
Knock-in
Knock-in of reporter genes (e.g., GFP) or epitope tags allows visualization and purification of proteins involved in hypertrophy. Knock-in of human disease alleles into mouse models recapitulates key features of cardiac hypertrophy.
Overexpression
CRISPR activation (CRISPRa) or transgenic overexpression of hypertrophic genes (e.g., TERT, NPPA) can induce hypertrophy in vitro and in vivo. Overexpression models are useful for gain-of-function studies and for testing therapeutic interventions.
How EDITGENE Supports cardiac muscle hypertrophy Research
Researchers studying cardiac muscle hypertrophy-related genes often need to determine whether a candidate gene is causally involved in the hypertrophic response. EDITGENE provides comprehensive CRISPR-based services to generate knockout, point-mutation, knock-in, and overexpression cell models, as well as CRISPR library screening and bioinformatics support. These tools enable rigorous functional validation of genes implicated in GO:0003300.
Contact EDITGENE today to design your custom CRISPR model for cardiac muscle hypertrophy research.
Frequently Asked Questions About cardiac muscle hypertrophy
What is cardiac muscle hypertrophy (GO:0003300)?
Cardiac muscle hypertrophy is the enlargement of the heart muscle due to an increase in the size of cardiac muscle cells without cell division, as defined by the Gene Ontology.
What genes are involved in cardiac muscle hypertrophy?
Key genes include NPPA, NPPB, MYH7, TERT, MTOR, AKT1, MAPK1, GATA4, MEF2C, and noncoding RNAs such as MIR133A1 and MALAT1.
How is cardiac muscle hypertrophy regulated?
It is regulated by mechanical stretch, neurohumoral factors, PI3K/Akt/mTOR signaling, MAPK cascades, calcineurin/NFAT, AMPK, and noncoding RNAs.
What diseases are associated with cardiac muscle hypertrophy?
It is associated with hypertensive heart disease, hypertrophic cardiomyopathy, metabolic cardiomyopathies, and heart failure.
What is the difference between hypertrophy and hyperplasia?
Hypertrophy involves an increase in cell size without cell division, whereas hyperplasia involves an increase in cell number; cardiac muscle hypertrophy is specifically the former.
Can CRISPR be used to study cardiac muscle hypertrophy?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models enable causal testing of genes in cardiomyocytes and animal models.
What methods are used to study cardiac muscle hypertrophy?
Common methods include RNA-seq, ChIP-seq, proteomics, echocardiography, confocal microscopy, and CRISPR screens.
What is the role of TERT in cardiac muscle hypertrophy?
Telomerase reverse transcriptase (TERT) promotes cardiac muscle cell proliferation, hypertrophy, and survival.
How do noncoding RNAs regulate cardiac muscle mass?
Noncoding RNAs, including microRNAs and long noncoding RNAs, modulate hypertrophic signaling pathways and gene expression.
Is there a limit to cardiac muscle hypertrophy?
Some studies suggest a potential upper limit to cardiac muscle hypertrophy, beyond which further growth may be detrimental.
Conclusion
Cardiac muscle hypertrophy (GO:0003300) is a fundamental biological process that underlies the heart's response to stress and is central to the pathogenesis of heart failure and cardiomyopathies. Advances in CRISPR-based models and multi-omics technologies are accelerating the discovery of molecular regulators and therapeutic targets. EDITGENE's comprehensive services support researchers in dissecting the mechanisms of cardiac hypertrophy with precision and scale.
References
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