GO:1903946 negative regulation of ventricular cardiac muscle cell action potential: Mechanism, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:1903946 describes any process that stops, prevents, or reduces the frequency, rate, or extent of the ventricular cardiac muscle cell action potential.
• The ventricular action potential is shaped by a precise balance of inward and outward ion currents, including Na+, Ca2+, K+, and Cl- currents.
• Negative regulation can occur through reduced excitability, altered current kinetics, or changes in ion homeostasis and volume regulation.
• Key molecular players include voltage-gated ion channels (e.g., SCN5A, CACNA1C, KCNQ1, KCNH2), auxiliary subunits (e.g., KCNE2), and signaling proteins such as RhoA.
• Dysregulation of this process is linked to arrhythmias, heart failure, and drug-induced cardiotoxicity, making it a critical area for cardiac safety and therapeutic research.
• CRISPR-based models (knockout, point mutation, knock-in, overexpression) enable precise dissection of gene function in this pathway and are essential for target validation.
Description
The ventricular cardiac muscle cell action potential is the electrical signal that triggers each heartbeat, and its precise regulation is essential for normal cardiac function. GO:1903946, negative regulation of ventricular cardiac muscle cell action potential, refers to any biological process that reduces the frequency, rate, or extent of this electrical event. Understanding this term is crucial because even subtle changes in action potential duration or frequency can predispose to life-threatening arrhythmias and sudden cardiac death. Researchers study this process to identify molecular targets for antiarrhythmic drugs, to assess drug safety, and to uncover mechanisms of inherited cardiac disorders. The action potential is generated by the coordinated activity of multiple ion channels and transporters, and its negative regulation can be achieved through diverse mechanisms, including altered channel expression, modulation of gating properties, or changes in intracellular ion concentrations. This article synthesizes authoritative QuickGO data and verified PubMed literature to provide a comprehensive overview of GO:1903946, covering its definition, molecular basis, key genes, disease relevance, and cutting-edge research methods including CRISPR-based models.
negative regulation of ventricular cardiac muscle cell action potential At A Glance
| GO ID | GO:1903946 |
|---|---|
| GO term | negative regulation of ventricular cardiac muscle cell action potential |
| Ontology | biological_process |
| Synonym | down regulation of ventricular cardiac muscle cell action potential, down-regulation of ventricular cardiac muscle cell action potential, downregulation of ventricular cardiac muscle cell action potential, inhibition of ventricular cardiac muscle cell action potential |
| Major function | Reduces the frequency, rate, or extent of the ventricular cardiac muscle cell action potential, thereby modulating cardiac electrical activity. |
| Related cellular components | Sarcolemma, ion channel complexes, T-tubules, intercalated discs. |
| Related molecular functions | Ion channel activity, ion transporter activity, channel regulation. |
| Key ion currents involved | INa, ICa-L, Ito, IKr, IKs, IK1, ICl. |
| Physiological context | Maintains normal heart rhythm and prevents arrhythmias. |
What Is GO:1903946?
GO:1903946 is a biological process term defined as any process that stops, prevents, or reduces the frequency, rate, or extent of the ventricular cardiac muscle cell action potential. In other words, it encompasses all molecular and cellular events that lead to a decrease in the electrical excitability or the duration/frequency of action potentials specifically in ventricular cardiomyocytes. This regulation is distinct from effects on atrial or nodal cells and is critical for maintaining normal heart rhythm.
Why Is negative regulation of ventricular cardiac muscle cell action potential Important in Cell Biology?
GO:1903946 is fundamentally important because the ventricular action potential governs cardiac contraction and rhythm, and its negative regulation directly impacts heart rate and contractility. Dysregulation of this process can lead to arrhythmias, heart failure, and increased susceptibility to drug-induced cardiotoxicity. Understanding the mechanisms that negatively regulate the ventricular action potential is therefore essential for developing safe and effective therapies for cardiac diseases and for interpreting cardiac safety data in drug development.
• Maintains normal cardiac rhythm by preventing excessive excitability.
• Protects against arrhythmias such as ventricular tachycardia and fibrillation.
• Modulates the effects of antiarrhythmic drugs that target ion channels.
• Influences cardiac contractility by altering calcium handling.
• Plays a role in heart failure remodeling, where action potential prolongation is common.
• Contributes to the response to metabolic stress, such as changes in NAD/ammonia levels.
• Involved in the regulation of cardiac sodium current by small G-proteins like RhoA.
• Critical for understanding genetic channelopathies (e.g., long QT syndrome).
• Provides targets for gene therapy and precision medicine in cardiology.
• Essential for cardiac safety pharmacology and drug development.
What Happens During negative regulation of ventricular cardiac muscle cell action potential?
Reduction of inward depolarizing currents
In simple terms: The cell receives less 'go' signal to start an action potential.
Negative regulation can occur by reducing the amplitude or availability of inward currents, particularly the fast sodium current (INa) and L-type calcium current (ICa-L). For example, inhibition of INa by signaling molecules such as RhoA reduces excitability. Similarly, modulation of L-type calcium channels by auxiliary subunits like KCNE2 can decrease calcium influx, thereby shortening or reducing the action potential. Calcium influx during the action potential is a key determinant of its plateau phase, and its reduction directly limits action potential duration and frequency.
Enhancement of outward repolarizing currents
In simple terms: The cell gets a stronger 'stop' signal to end the action potential.
Increasing outward potassium currents (e.g., Ito, IKr, IKs, IK1) accelerates repolarization and can reduce action potential duration and frequency. For instance, activation of certain potassium channels or increased expression of their subunits can enhance repolarization, leading to negative regulation of the action potential. Chloride currents also contribute to repolarization and volume regulation, and their modulation can affect action potential duration.
Alteration of ion homeostasis and cell volume
In simple terms: Changes in the cell's internal environment can make it less excitable.
Negative regulation can also result from changes in intracellular ion concentrations or cell volume. For example, chloride homeostasis and volume regulation influence the cardiac action potential, and disruptions can lead to reduced excitability. Metabolic factors such as NAD and ammonia can modulate ion channels and exchangers, thereby affecting contractility and electrical activity.
Modulation by signaling pathways
In simple terms: Chemical signals inside the cell can turn down the action potential.
Various signaling cascades can negatively regulate the ventricular action potential. Small G-proteins like RhoA have been shown to inhibit cardiac fast sodium current, reducing excitability. Other pathways, including those involving protein kinases and phosphatases, can alter ion channel phosphorylation and trafficking, leading to decreased action potential frequency or duration. These signaling mechanisms provide potential targets for therapeutic intervention.
Beat-to-beat variability and frequency reduction
In simple terms: The heart cell fires less often or less regularly.
Negative regulation can manifest as a reduction in the frequency of action potentials or increased beat-to-beat variability. Studies in canine ventricular myocytes have shown that contributions of individual ion currents to action potential duration variability are complex, and shifts in current balance can lead to reduced firing rates. This variability is clinically relevant because it can predispose to arrhythmias.
Key Genes Involved in GO:1903946 negative regulation of ventricular cardiac muscle cell action potential
The following genes and proteins are key players in the negative regulation of the ventricular cardiac muscle cell action potential, based on verified literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| SCN5A | Encodes Nav1.5, the alpha subunit of the cardiac sodium channel responsible for INa; inhibition reduces excitability. | Mutations cause Brugada syndrome and long QT syndrome; target for antiarrhythmic drugs. |
| CACNA1C | Encodes Cav1.2, the alpha subunit of L-type calcium channel; reduced activity decreases ICa-L and action potential duration. | Mutations linked to Timothy syndrome and Brugada syndrome; drug target. |
| KCNQ1 | Encodes Kv7.1, alpha subunit of IKs; increased activity enhances repolarization. | Mutations cause long QT syndrome; target for IKs modulators. |
| KCNH2 | Encodes Kv11.1, alpha subunit of IKr; enhanced activity shortens action potential. | Mutations cause long QT syndrome; target for class III antiarrhythmics. |
| KCNE2 | Encodes MinK-related peptide 1, auxiliary subunit that modulates L-type calcium channel and IKr. | Mutations associated with arrhythmias; modulates drug sensitivity. |
| KCNE1 | Encodes MinK, auxiliary subunit for KCNQ1; modulates IKs. | Mutations cause long QT syndrome and deafness. |
| KCNJ2 | Encodes Kir2.1, responsible for IK1; increased activity stabilizes resting potential and reduces excitability. | Mutations cause Andersen-Tawil syndrome; target for IK1 modulators. |
| RhoA | Small G-protein that inhibits cardiac fast sodium current, reducing excitability. | Potential target for modulating INa in disease. |
| SLC8A1 | Encodes NCX1, sodium-calcium exchanger; modulates calcium homeostasis and action potential. | Involved in heart failure and arrhythmias; target for NCX inhibitors. |
| ATP1A1 | Encodes Na+/K+-ATPase alpha subunit; maintains ion gradients essential for action potential. | Target for cardiac glycosides; involved in heart failure. |
| CLCN3 | Encodes chloride channel 3; contributes to ICl and volume regulation. | Modulates action potential duration and cell volume. |
| SCN1B | Encodes beta1 subunit of sodium channel; modulates INa gating. | Mutations linked to Brugada syndrome and epilepsy. |
| CALM1 | Encodes calmodulin; regulates calcium channels and signaling. | Mutations cause long QT syndrome and CPVT. |
| PRKACA | Encodes protein kinase A catalytic subunit; phosphorylates ion channels, altering activity. | Modulates beta-adrenergic effects on action potential. |
| PPP1CA | Encodes protein phosphatase 1 catalytic subunit; dephosphorylates ion channels. | Regulates channel activity and action potential duration. |
| GNAI2 | Encodes Gi alpha subunit; inhibits adenylyl cyclase, reducing PKA activity. | Modulates parasympathetic effects on heart rate and action potential. |
| ADRB1 | Encodes beta1-adrenergic receptor; activation increases PKA signaling and can enhance or reduce action potential depending on context. | Target for beta-blockers in heart failure and arrhythmias. |
| NOS1 | Encodes neuronal nitric oxide synthase; modulates ion channel function via nitric oxide. | Involved in heart failure and arrhythmias. |
How Is negative regulation of ventricular cardiac muscle cell action potential Regulated?
The negative regulation of the ventricular cardiac muscle cell action potential is itself tightly regulated by multiple signaling pathways. Beta-adrenergic signaling via PKA can phosphorylate ion channels and either enhance or reduce action potential duration depending on the channel and context. Parasympathetic signaling via Gi proteins reduces cAMP and PKA activity, often leading to decreased excitability. Small G-proteins such as RhoA can directly inhibit sodium current. Additionally, metabolic factors like NAD and ammonia can modulate ion channels and exchangers, affecting contractility and electrical activity. These regulatory mechanisms ensure that the action potential adapts to physiological demands while preventing arrhythmias.
negative regulation of ventricular cardiac muscle cell action potential and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| KCNH2 | Long QT syndrome type 2; reduced IKr prolongs action potential. | Knockout or point mutation in hiPSC-CMs; patch clamp to measure IKr and APD. |
| SCN5A | Brugada syndrome and long QT syndrome type 3; altered INa. | Knock-in of patient mutations in hiPSC-CMs; measure INa and APD. |
| CACNA1C | Timothy syndrome; gain-of-function increases ICa-L. | Overexpression or knock-in in cardiomyocytes; calcium imaging and patch clamp. |
| RhoA | Modulates INa; potential role in arrhythmias. | Knockout or overexpression in cardiac cells; measure INa and excitability. |
| CLCN3 | Volume regulation and action potential duration. | Knockout in mouse models; measure ICl and APD. |
Arrhythmias and channelopathies
Dysregulation of the negative regulation of the ventricular action potential is central to many arrhythmias. For example, loss-of-function mutations in KCNH2 or KCNQ1 reduce repolarizing currents, prolonging the action potential and causing long QT syndrome, which predisposes to torsades de pointes. Conversely, gain-of-function mutations in SCN5A can enhance INa and cause long QT syndrome type 3. Understanding these mechanisms is critical for diagnosis and treatment.
Heart failure
In heart failure, electrical remodeling often leads to prolonged action potential duration and increased arrhythmia risk. Changes in ion channel expression and function, including reduced Ito and IK1, contribute to this phenotype. Negative regulation of the action potential may be impaired, and targeting these pathways could improve outcomes.
Drug-induced cardiotoxicity
Many drugs can inadvertently block ion channels and alter the action potential, leading to acquired long QT syndrome and sudden death. For instance, blockade of IKr by certain medications is a common cause. Understanding the negative regulation of the action potential helps in predicting and preventing such adverse effects during drug development.
Metabolic and ischemic conditions
Metabolic stress, such as ischemia, alters ion homeostasis and can affect action potential regulation. NAD and ammonia levels change during ischemia and can modulate ion channels and exchangers, contributing to arrhythmogenesis. Chloride homeostasis and volume regulation are also disrupted in ischemia, affecting action potential duration.
From negative regulation of ventricular cardiac muscle cell action potential-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of a gene enhance or reduce action potential frequency? | Knockout in hiPSC-derived cardiomyocytes or mouse ventricular myocytes. |
| How does a specific point mutation affect ion channel gating? | Point mutation knock-in in hiPSC-CMs; patch clamp analysis. |
| Can a gene variant alter drug sensitivity? | Knock-in of variant in cell lines; high-throughput screening. |
| Where is a protein localized during action potential changes? | Tagged knock-in (e.g., GFP) in cardiomyocytes; live imaging. |
| Does overexpression of a signaling protein reduce excitability? | Overexpression in primary cardiomyocytes or cell lines; electrophysiology. |
| What is the effect of a gene on action potential duration variability? | Knockout or overexpression in canine ventricular myocytes; beat-to-beat variability analysis. |
How to Study the negative regulation of ventricular cardiac muscle cell action potential Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Patch clamp | Action potential duration, ion currents | Studying effects of gene knockout or drugs on excitability. |
| Calcium imaging | Intracellular calcium transients | Assessing calcium handling and contractility. |
| Optical mapping | Action potential propagation and arrhythmias | Tissue-level electrophysiology. |
| RNA-seq | Gene expression changes | Identifying molecular pathways in disease models. |
| Proteomics | Protein expression and modifications | Detecting channel subunit changes. |
| Western blot | Protein levels and phosphorylation | Validating signaling changes. |
| CRISPR screening | Gene function in action potential regulation | High-throughput target discovery. |
| hiPSC-CM models | Human-relevant electrophysiology | Disease modeling and drug testing. |
Patch clamp electrophysiology
Patch clamp is the gold standard for measuring action potentials and ion currents in single cardiomyocytes. It allows precise quantification of action potential duration, frequency, and the contributions of individual currents. This method is essential for studying negative regulation of the ventricular action potential.
Calcium imaging
Calcium imaging using fluorescent indicators measures intracellular calcium transients, which are tightly linked to action potential and contractility. It can reveal how negative regulation affects calcium handling.
Optical mapping
Optical mapping with voltage-sensitive dyes enables simultaneous recording of action potentials from multiple sites in cardiac tissue or monolayers, providing insights into conduction and arrhythmogenesis.
Molecular biology and omics
RNA-seq, proteomics, and Western blotting quantify expression of ion channels and signaling proteins. These methods help identify molecular changes underlying negative regulation.
How CRISPR Can Be Used to Study GO:1903946 negative regulation of ventricular cardiac muscle cell action potential
Knockout
CRISPR knockout of candidate genes in hiPSC-derived cardiomyocytes or cell lines can reveal their role in negative regulation of the action potential. For example, knocking out KCNH2 reduces IKr and prolongs action potential, mimicking long QT syndrome. Knockout of RhoA may increase INa and excitability.
Point Mutation
Introducing specific point mutations (e.g., in SCN5A or KCNH2) using CRISPR base editing or HDR allows precise modeling of channelopathies. These models help determine how mutations alter ion channel function and action potential regulation.
Knock-in
Knock-in of reporter tags (e.g., GFP) or patient-specific mutations enables tracking of protein localization and function. For instance, tagging CACNA1C can reveal its trafficking in response to negative regulation.
Overexpression
CRISPR activation (CRISPRa) or lentiviral overexpression can increase expression of genes like KCNQ1 to enhance repolarization and negatively regulate the action potential. This approach is useful for gain-of-function studies.
How EDITGENE Supports negative regulation of ventricular cardiac muscle cell action potential Research
Researchers studying negative regulation of ventricular cardiac muscle cell action potential-related genes often need to determine whether a candidate gene is causally involved in modulating electrical activity. This requires precise genetic models that can isolate the gene's function in a relevant cellular context. EDITGENE provides a comprehensive suite of CRISPR-based services to accelerate this research.
Contact EDITGENE today to design your custom CRISPR model for negative regulation of ventricular cardiac muscle cell action potential research.
Frequently Asked Questions About negative regulation of ventricular cardiac muscle cell action potential
What is GO:1903946?
GO:1903946 is a Gene Ontology biological process term defined as any process that stops, prevents, or reduces the frequency, rate, or extent of the ventricular cardiac muscle cell action potential.
What genes are involved in negative regulation of ventricular cardiac muscle cell action potential?
Key genes include SCN5A, CACNA1C, KCNQ1, KCNH2, KCNE2, RhoA, and others that encode ion channels and signaling proteins.
How is the ventricular action potential negatively regulated?
It can be negatively regulated by reducing inward currents (e.g., INa, ICa-L), enhancing outward currents (e.g., IKr, IKs), altering ion homeostasis, or through signaling pathways like RhoA.
Why is negative regulation of the ventricular action potential important?
It is crucial for maintaining normal heart rhythm and preventing arrhythmias; dysregulation can lead to long QT syndrome, heart failure, and drug-induced cardiotoxicity.
What diseases are associated with dysregulation of this process?
Arrhythmias, long QT syndrome, Brugada syndrome, heart failure, and drug-induced cardiotoxicity.
What methods are used to study negative regulation of the ventricular action potential?
Patch clamp electrophysiology, calcium imaging, optical mapping, RNA-seq, proteomics, and CRISPR-based models.
How can CRISPR help study this process?
CRISPR knockout, point mutation, knock-in, and overexpression models allow precise manipulation of genes to assess their effects on action potential regulation.
What is the role of KCNE2 in action potential regulation?
KCNE2 modulates the L-type calcium channel and IKr, affecting action potential duration and excitability.
How does RhoA affect the cardiac action potential?
RhoA inhibits the fast sodium current, reducing excitability and contributing to negative regulation.
What are the challenges in studying negative regulation of the ventricular action potential?
Challenges include the complex interplay of multiple ion currents, species differences, and the need for human-relevant models like hiPSC-CMs.
Conclusion
GO:1903946, negative regulation of ventricular cardiac muscle cell action potential, is a critical biological process that safeguards cardiac electrical stability. Its molecular underpinnings involve a delicate balance of ion currents and signaling pathways, with key roles for genes such as SCN5A, CACNA1C, KCNQ1, KCNH2, and RhoA. Dysregulation of this process is implicated in arrhythmias, heart failure, and drug-induced cardiotoxicity, making it a prime target for therapeutic development. Advances in CRISPR-based models and electrophysiological methods are enabling researchers to dissect these mechanisms with unprecedented precision. EDITGENE's comprehensive services support these efforts, from knockout and point mutation models to library screening and bioinformatics, empowering the next generation of cardiac research.
References
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