GO:0003198 epithelial to mesenchymal transition involved in endocardial cushion formation: Developmental EMT, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0003198 describes the epithelial-to-mesenchymal transition (EMT) that cardiac epithelial cells undergo during endocardial cushion formation, a critical step in heart valve and septum development.
• The process involves loss of apical/basolateral polarity, disassembly of intercellular junctions, basement membrane degradation, and acquisition of a migratory mesenchymal phenotype.
• Key signaling pathways include TGFβ, BMP, Notch, and Wnt, with transcription factors such as Snail, Slug, Twist, and Tbx20 orchestrating the transition.
• MicroRNAs (e.g., miR-23b, miR-199a) and proteins like Tmem100 and YAP modulate EMT during cushion formation.
• Dysregulation of this process is linked to congenital heart defects such as bicuspid aortic valve and outflow tract septation anomalies.
• Research models include mouse en face endocardial cushion preparations, Syrian hamster models, and CRISPR-engineered cell lines for mechanistic studies.
Description
Epithelial to mesenchymal transition involved in endocardial cushion formation (GO:0003198) is a specialized developmental EMT that occurs in the embryonic heart. During this process, endocardial cells lining the atrioventricular canal and outflow tract lose their epithelial characteristics and transform into migratory mesenchymal cells that populate the endocardial cushions, precursors of heart valves and septa. This transition is essential for proper cardiac morphogenesis, and its disruption leads to congenital heart defects. Researchers study GO:0003198 to understand the molecular drivers of cardiac development, to model human valve diseases, and to identify therapeutic targets for congenital heart conditions. The process is regulated by a complex interplay of signaling pathways, transcription factors, and microRNAs, making it a rich area for CRISPR-based functional genomics.
epithelial to mesenchymal transition involved in endocardial cushion formation At A Glance
| GO ID | GO:0003198 |
|---|---|
| GO term | epithelial to mesenchymal transition involved in endocardial cushion formation |
| Ontology | biological_process |
| Synonym | none |
| Major function | Cardiac epithelial cells lose polarity and junctions, degrade basement membrane, and become migratory mesenchymal cells contributing to endocardial cushion formation |
| Related process | Endothelial-to-mesenchymal transition (EndoMT) in cushion development |
| Key signaling pathways | TGFβ, BMP, Notch, Wnt |
| Key transcription factors | Snail, Slug, Twist, Tbx20 |
| Associated microRNAs | miR-23b, miR-199a |
What Is GO:0003198?
GO:0003198 is defined as a transition where a cardiac epithelial cell loses apical/basolateral polarity, severs intercellular adhesive junctions, degrades basement membrane components, and becomes a migratory mesenchymal cell that will contribute to the formation of the endocardial cushion. This biological process is a specific type of epithelial-to-mesenchymal transition (EMT) restricted to the endocardial cells of the developing heart, and it is fundamental for the cellularization of endocardial cushions.
Why Is epithelial to mesenchymal transition involved in endocardial cushion formation Important in Cell Biology?
GO:0003198 is crucial for heart development because endocardial cushions are the primordia of cardiac valves and membranous septa. Defects in this EMT process cause congenital heart defects such as bicuspid aortic valve, septal defects, and outflow tract anomalies. Understanding the molecular regulation of this transition provides insights into both normal cardiogenesis and the pathogenesis of valve diseases, and it offers potential targets for regenerative medicine and tissue engineering.
• Essential for formation of endocardial cushions, which give rise to heart valves and septa.
• Dysregulation leads to congenital heart defects including bicuspid aortic valve and septal defects.
• Serves as a paradigm for studying EMT in development and disease.
• Involves crosstalk between multiple signaling pathways (TGFβ, BMP, Notch, Wnt).
• Regulated by microRNAs such as miR-23b and miR-199a, offering post-transcriptional control.
• Tmem100 and YAP are critical modulators of endothelial-mesenchymal transformation in cushions.
• Provides a model for understanding cell fate plasticity and migration.
• Relevant to tissue engineering of heart valves and regenerative strategies.
• Enables functional genomics screens to identify novel regulators of cardiac EMT.
• Conservation across species (mouse, hamster) facilitates translational studies.
What Happens During epithelial to mesenchymal transition involved in endocardial cushion formation?
Initiation and Loss of Epithelial Polarity
In simple terms: The endocardial cells first lose their organized top-bottom structure and prepare to move.
Endocardial cells lining the atrioventricular canal and outflow tract receive inductive signals from the adjacent myocardium, including BMP2 and TGFβ, which trigger the EMT program. These signals cause the cells to lose apical/basolateral polarity, a hallmark of epithelial cells, and begin to dismantle their cell-cell junctions. Tbx20 in the myocardium regulates Bmp2 expression, which is essential for initiating this process.
Disassembly of Intercellular Adhesive Junctions
In simple terms: The cells detach from each other by breaking down the glue that holds them together.
Downregulation of adhesion molecules such as E-cadherin and disruption of tight junctions occur, mediated by transcription factors like Snail and Slug. This step is critical for allowing cells to separate from the endocardial monolayer. MicroRNAs miR-23b and miR-199a impair EMT by targeting components of this junctional disassembly machinery.
Degradation of Basement Membrane
In simple terms: The cells chew through the underlying matrix to escape into the cushion space.
The endocardial cells secrete matrix metalloproteinases (MMPs) that degrade basement membrane components, facilitating invasion into the cardiac jelly. This degradation is a key step in acquiring migratory capacity. TGFβ signaling promotes MMP expression and activity during cushion EMT.
Acquisition of Migratory Mesenchymal Phenotype
In simple terms: The cells become free-moving and invade the cushion tissue.
Cells that successfully undergo EMT express mesenchymal markers such as α-smooth muscle actin, vimentin, and N-cadherin, and they migrate into the endocardial cushion. This migration is guided by chemotactic signals and requires cytoskeletal reorganization. YAP plays a dual role in driving TGFβ-mediated endothelial-to-mesenchymal transition, influencing both initiation and migration.
Contribution to Endocardial Cushion Formation
In simple terms: The migrated cells populate the cushion and later form valve and septum structures.
The mesenchymal cells that arise from EMT proliferate and contribute to the cellularized endocardial cushions, which subsequently remodel into heart valves and membranous septa. Defects in this step lead to malformations such as bicuspid aortic valve, as observed in Syrian hamster models. Tmem100 null embryos show impaired endothelial-mesenchymal transformation during atrioventricular cushion formation, highlighting its importance.
Key Genes Involved in GO:0003198 epithelial to mesenchymal transition involved in endocardial cushion formation
The following genes and proteins are central to the regulation and execution of epithelial to mesenchymal transition involved in endocardial cushion formation (GO:0003198).
| Gene | Major Role | Research Relevance |
|---|---|---|
| TGFβ | Induces EMT via Smad-dependent and independent pathways | Core signaling pathway; target for modulation |
| BMP2 | Myocardial signal that triggers endocardial EMT | Regulated by Tbx20; essential for initiation |
| Tbx20 | Transcription factor regulating Bmp2 expression | Links myocardial cues to endocardial EMT |
| Snail | Transcription factor repressing E-cadherin | Master regulator of EMT |
| Slug | Transcription factor promoting mesenchymal phenotype | Cooperates with Snail |
| Twist | Transcription factor enhancing cell migration | Downstream of TGFβ |
| YAP | Transcriptional co-activator driving TGFβ-mediated EndoMT | Dual role in initiation and migration |
| Tmem100 | Modulates endothelial-mesenchymal transformation | Loss impairs cushion formation |
| miR-23b | MicroRNA impairing EMT | Post-transcriptional regulator |
| miR-199a | MicroRNA impairing EMT | Post-transcriptional regulator |
| Notch | Signaling pathway influencing EMT timing | Crosstalk with TGFβ |
| Wnt | Signaling pathway promoting mesenchymal fate | Context-dependent |
| MMPs | Degrade basement membrane | Enable invasion |
| E-cadherin | Epithelial adhesion molecule | Downregulated during EMT |
| N-cadherin | Mesenchymal adhesion molecule | Upregulated during EMT |
| Vimentin | Mesenchymal marker | Indicates successful EMT |
| α-SMA | Mesenchymal marker | Contractile phenotype |
How Is epithelial to mesenchymal transition involved in endocardial cushion formation Regulated?
The process is regulated by a network of signaling pathways and transcription factors. TGFβ signaling is a primary driver, activating Smad2/3 and non-Smad pathways that induce EMT transcription factors. BMP2 from the myocardium initiates the process, and Tbx20 controls Bmp2 expression. Notch and Wnt pathways modulate the timing and extent of EMT. MicroRNAs such as miR-23b and miR-199a act as negative regulators by targeting mRNAs involved in EMT. YAP integrates mechanical and biochemical signals to drive TGFβ-mediated EndoMT. Tmem100 is required for proper endothelial-mesenchymal transformation, and its loss impairs cushion formation.
epithelial to mesenchymal transition involved in endocardial cushion formation and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| Tbx20 | Cardiac septal defects | Knockout mouse, point mutation knock-in |
| Tmem100 | Impaired cushion formation | Tmem100 null mouse embryos |
| YAP | Valve malformations | Conditional knockout or overexpression in endocardial cells |
| miR-23b/miR-199a | EMT impairment | Overexpression or sponge in zebrafish/mouse |
| BMP2 | Outflow tract defects | Myocardial-specific knockout |
Congenital Heart Defects
Disruption of GO:0003198 leads to congenital heart defects, including bicuspid aortic valve and outflow tract septation anomalies. In a Syrian hamster model, defective endocardial-to-mesenchymal transition underlies bicuspid aortic valve formation. Tbx20 mutations in humans are associated with cardiac septal defects, partly through impaired Bmp2-mediated EMT.
Valve Disease
Aberrant EMT during cushion formation can result in valve malformations such as thickened or fused leaflets, predisposing to stenosis or regurgitation later in life. Understanding the molecular players like YAP and Tmem100 may offer therapeutic targets.
Cancer Analogies
Although GO:0003198 is developmental, the EMT program shares molecular features with cancer metastasis, including loss of E-cadherin and gain of mesenchymal markers. Studying this process provides insights into general EMT mechanisms.
From epithelial to mesenchymal transition involved in endocardial cushion formation-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does gene X regulate endocardial EMT? | Knockout in mouse endocardial cells |
| What is the effect of a point mutation in gene Y? | CRISPR knock-in of specific mutation in cell line or mouse |
| How does overexpression of gene Z affect cushion formation? | Transgenic overexpression in zebrafish or mouse |
| Where and when is protein W expressed during EMT? | Tagged knock-in (e.g., GFP) for live imaging |
| What are the transcriptomic changes during EMT? | RNA-seq of sorted endocardial cells from wild-type and mutant embryos |
| Can we screen for novel regulators? | CRISPR library screening in primary endocardial cells or organoids |
How to Study the epithelial to mesenchymal transition involved in endocardial cushion formation Process
| Method | What It Measures | Typical Application |
|---|---|---|
| En face cushion preparation | Cell morphology and migration | Planar morphogenesis analysis |
| Lineage tracing | Cell fate and contribution | Tracking endocardial-derived mesenchymal cells |
| Single-cell RNA-seq | Transcriptomic heterogeneity | Identifying EMT subpopulations |
| Immunofluorescence | Protein localization and markers | Detecting E-cadherin, N-cadherin, vimentin |
| Collagen gel invasion assay | Migratory and invasive capacity | Functional assessment of EMT |
| CRISPR knockout | Gene function | Testing candidate regulators |
| Western blot | Protein expression levels | Validating EMT markers |
| In situ hybridization | Spatial gene expression | Localizing mRNAs in cushions |
En Face Endocardial Cushion Preparation
This technique allows planar morphogenesis analysis in mouse embryos, enabling visualization of EMT events in intact cushions. It is useful for studying cell shape changes and migration.
Lineage Tracing and Live Imaging
Genetic lineage tracing using Tie2-Cre or Nfatc1-Cre combined with fluorescent reporters allows tracking of endocardial cells undergoing EMT. Live imaging in zebrafish or mouse embryos provides dynamic insights.
Transcriptomics and Single-Cell RNA-seq
RNA sequencing of sorted endocardial cells at different stages of EMT reveals gene expression changes and identifies novel regulators. Single-cell approaches capture heterogeneity.
Functional Assays
In vitro EMT assays using primary endocardial cells or explants can test the effect of gene knockdown or overexpression. Collagen gel invasion assays measure migratory capacity.
How CRISPR Can Be Used to Study GO:0003198 epithelial to mesenchymal transition involved in endocardial cushion formation
Knockout
CRISPR knockout of candidate genes in endocardial cell lines or mouse embryos can determine their requirement for EMT. For example, Tmem100 knockout impairs endothelial-mesenchymal transformation. Knockout of Tbx20 in myocardium affects Bmp2 expression and EMT.
Point Mutation
Introducing specific point mutations (e.g., in YAP or TGFβ receptors) via CRISPR knock-in allows dissection of phosphorylation sites or binding interfaces critical for EMT signaling.
Knock-in
Tagged knock-in of fluorescent proteins (e.g., GFP) into endogenous loci enables live imaging of EMT. Knock-in of lineage markers helps track cell fate.
Overexpression
CRISPR activation (CRISPRa) or transgenic overexpression can test gain-of-function effects. Overexpression of miR-23b or miR-199a impairs EMT, validating their roles.
How EDITGENE Supports epithelial to mesenchymal transition involved in endocardial cushion formation Research
Researchers studying epithelial to mesenchymal transition involved in endocardial cushion formation-related genes often need to determine whether a candidate gene is causally involved in the process or merely correlated. EDITGENE provides comprehensive CRISPR-based services to enable such functional validation.
Contact EDITGENE today to design your custom CRISPR model for epithelial to mesenchymal transition involved in endocardial cushion formation research.
Frequently Asked Questions About epithelial to mesenchymal transition involved in endocardial cushion formation
What is GO:0003198?
GO:0003198 is the Gene Ontology term for epithelial to mesenchymal transition involved in endocardial cushion formation, a developmental process where cardiac epithelial cells become migratory mesenchymal cells.
What genes are involved in epithelial to mesenchymal transition involved in endocardial cushion formation?
Key genes include TGFβ, BMP2, Tbx20, Snail, Slug, Twist, YAP, Tmem100, and microRNAs miR-23b and miR-199a.
Why is endocardial cushion EMT important?
It is essential for heart valve and septum formation; defects cause congenital heart defects.
What signaling pathways regulate this EMT?
TGFβ, BMP, Notch, and Wnt pathways are major regulators.
How can I study GO:0003198 in the lab?
Use en face cushion preparations, lineage tracing, RNA-seq, and CRISPR knockout models.
What diseases are linked to defects in this process?
Bicuspid aortic valve, septal defects, and other congenital heart anomalies.
What is the role of YAP in endocardial EMT?
YAP drives TGFβ-mediated endothelial-to-mesenchymal transition and has a dual role in initiation and migration.
How do microRNAs affect endocardial cushion EMT?
miR-23b and miR-199a impair EMT by targeting mRNAs involved in the process.
What animal models are used to study endocardial cushion EMT?
Mouse, zebrafish, and Syrian hamster models are commonly used.
Can CRISPR be used to study this process?
Yes, CRISPR knockout, knock-in, and overexpression models enable functional studies of candidate genes.
Conclusion
GO:0003198 encompasses the specialized EMT that drives endocardial cushion formation, a cornerstone of heart development. Its molecular regulation by signaling pathways, transcription factors, and microRNAs is increasingly well understood, and its dysregulation is directly linked to congenital heart defects. Continued research using advanced CRISPR models and imaging techniques will further illuminate this process and may lead to new therapeutic strategies.
References
- 1. Wang J et al.. 2026. The regulation of endothelial-to-mesenchymal transition in endocardial cushion development: Signaling pathways and transcription factors.. Differentiation 151:100987 PMID: 42600378
- 2. Bonet F et al.. 2015. MiR-23b and miR-199a impair epithelial-to-mesenchymal transition during atrioventricular endocardial cushion formation.. Dev Dyn 244(10):1259-75 PMID: 26198058
- 3. Savorani C et al.. 2021. A dual role of YAP in driving TGFβ-mediated endothelial-to-mesenchymal transition.. J Cell Sci 134(15) PMID: 34338295
- 4. Soto-Navarrete MT et al.. 2025. Endocardial-to-mesenchymal transition underlies cardiac outflow tract septation and bicuspid aortic valve formation in the Syrian hamster model.. Sci Rep 15(1):8583 PMID: 40074779
- 5. Gonzalez-Costa T et al.. 2022. En Face Endocardial Cushion Preparation for Planar Morphogenesis Analysis in Mouse Embryos.. J Vis Exp PMID: 35969077
- 6. Cai X et al.. 2011. Myocardial Tbx20 regulates early atrioventricular canal formation and endocardial epithelial-mesenchymal transition via Bmp2.. Dev Biol 360(2):381-90 PMID: 21983003
- 7. Person AD et al.. 2005. Cell biology of cardiac cushion development.. Int Rev Cytol 243:287-335 PMID: 15797462
- 8. Mizuta K et al.. 2015. Impairment of endothelial-mesenchymal transformation during atrioventricular cushion formation in Tmem100 null embryos.. Dev Dyn 244(1):31-42 PMID: 25318679
