GO:0034361 very-low-density lipoprotein particle: Components, Assembly and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0034361 describes the very-low-density lipoprotein (VLDL) particle, a triglyceride-rich lipoprotein complex with a density of about 1.006 g/ml and a diameter of 20-80 nm.
• VLDL is assembled in the liver and transports endogenous triglycerides and newly synthesized cholesterol to peripheral tissues.
• The particle is typically composed of apolipoprotein B-100 (APOB100), APOE, and APOCs, with APOB100 serving as the essential structural scaffold.
• VLDL biogenesis and secretion are complex processes requiring coordinated action of multiple proteins, lipids, and cellular machinery.
• Overproduction of VLDL is a hallmark of insulin resistance and diabetic dyslipidemia, contributing to cardiovascular risk.
• Apolipoprotein B-containing lipoproteins, including VLDL, are superior markers of cardiovascular risk compared to LDL cholesterol.
Description
The very-low-density lipoprotein (VLDL) particle, defined by the Gene Ontology term GO:0034361, is a triglyceride-rich lipoprotein complex that plays a central role in lipid transport and metabolism. It is assembled primarily in the liver and secreted into the bloodstream to deliver endogenous triglycerides and newly synthesized cholesterol to peripheral tissues. VLDL is characterized by a density of approximately 1.006 g/ml and a diameter ranging from 20 to 80 nm, and it typically contains apolipoprotein B-100 (APOB100), apolipoprotein E (APOE), and apolipoproteins of the C family (APOCs). For researchers, VLDL is a critical entity because its overproduction and impaired clearance are intimately linked to metabolic disorders such as insulin resistance, diabetic dyslipidemia, and atherosclerosis. The particle serves as a precursor to intermediate-density lipoprotein (IDL) and low-density lipoprotein (LDL), and its apolipoprotein B content is a robust marker of cardiovascular risk. Understanding the molecular mechanisms of VLDL assembly, secretion, and regulation is essential for developing therapeutic strategies targeting dyslipidemia and cardiovascular disease. This article provides a comprehensive overview of the VLDL particle based on authoritative QuickGO data and verified PubMed literature, covering its structure, function, regulation, disease associations, and research methodologies including CRISPR-based models.
very-low-density lipoprotein particle At A Glance
| GO ID | GO:0034361 |
|---|---|
| GO term | very-low-density lipoprotein particle |
| Ontology | cellular_component |
| Synonym | VLDL complex, VLDL particle, very-low-density lipoprotein complex |
| Major function | Transport of endogenous triglycerides and cholesterol from the liver to peripheral tissues |
| Composition | APOB100, APOE, APOCs, triglycerides, cholesterol, phospholipids |
| Density | Approximately 1.006 g/ml |
| Diameter | 20-80 nm |
| Location | Blood plasma |
What Is GO:0034361?
GO:0034361 defines the very-low-density lipoprotein particle as a triglyceride-rich lipoprotein complex found in blood, typically composed of APOB100, APOE, and APOCs, with a density of about 1.006 g/ml and a diameter between 20-80 nm. It functions to transport endogenous products, specifically newly synthesized cholesterol and triglycerides, from the liver to peripheral tissues.
Why Is very-low-density lipoprotein particle Important in Cell Biology?
The VLDL particle is fundamentally important because it is the primary vehicle for distributing energy-rich triglycerides and cholesterol from the liver to tissues, and its dysregulation is a central feature of common metabolic diseases. Overproduction of VLDL, particularly in the context of insulin resistance, leads to diabetic dyslipidemia and increased cardiovascular risk. Moreover, the apolipoprotein B component of VLDL is now recognized as a superior marker for cardiovascular risk compared to traditional LDL cholesterol measurements. Research into VLDL biology informs the development of targeted therapies for dyslipidemia and atherosclerosis.
• VLDL is the main transporter of endogenous triglycerides from the liver to peripheral tissues.
• It serves as the precursor for IDL and LDL, linking hepatic lipid metabolism to atherogenic lipoprotein fractions.
• Overproduction of VLDL is a hallmark of insulin resistance and type 2 diabetes.
• Apolipoprotein B-containing lipoproteins, including VLDL, are stronger predictors of coronary artery disease risk than LDL cholesterol.
• VLDL assembly and secretion require a complex interplay of proteins, lipids, and cellular machinery, making it a rich area for molecular research.
• Genetic and environmental factors affecting VLDL metabolism are targets for therapeutic intervention in cardiovascular disease.
• Studying VLDL provides insights into hepatic lipid handling and the pathogenesis of non-alcoholic fatty liver disease.
• VLDL particles can be directly assessed using advanced biosensors, enabling precise quantification for clinical research.
• Kinetic studies of VLDL apolipoprotein B metabolism in humans reveal important physiological parameters.
• Understanding VLDL biogenesis is essential for developing CRISPR-based models of dyslipidemia.
What Happens During very-low-density lipoprotein particle?
VLDL Assembly in the Liver
In simple terms: The liver builds VLDL particles by combining fats with special proteins.
VLDL assembly occurs in hepatocytes and involves the coordinated synthesis and lipidation of apolipoprotein B-100 (APOB100). The process begins with the co-translational translocation of APOB100 into the endoplasmic reticulum (ER), where it is lipidated by microsomal triglyceride transfer protein (MTTP) to form a primordial particle. This particle then undergoes further lipidation, potentially in the ER and post-ER compartments, to become a mature VLDL. The entire process requires a village of proteins, including MTTP, APOB100, and various lipid-modifying enzymes.
Secretion into the Bloodstream
In simple terms: Once built, VLDL is released from the liver into the blood.
After assembly, mature VLDL particles are secreted from hepatocytes into the sinusoidal space and enter the bloodstream. This secretion step is regulated by multiple factors, including the availability of lipids, the activity of MTTP, and the overall metabolic state of the liver. In insulin-resistant states, hepatic VLDL secretion is often increased, contributing to hypertriglyceridemia.
Lipid Delivery to Peripheral Tissues
In simple terms: VLDL delivers fats to muscles and fat tissue for energy or storage.
In the circulation, VLDL interacts with lipoprotein lipase (LPL) on the surface of capillary endothelial cells in peripheral tissues such as muscle and adipose tissue. LPL hydrolyzes the triglycerides within VLDL, releasing free fatty acids that are taken up by these tissues for energy production or storage. This process converts VLDL into smaller, denser remnants, ultimately leading to the formation of IDL and LDL.
Metabolic Fate and Clearance
In simple terms: After delivering its fats, VLDL remnants are either taken up by the liver or turned into other lipoproteins.
Following triglyceride depletion, VLDL remnants (IDL) can be taken up by the liver via receptor-mediated endocytosis involving the LDL receptor and related receptors, or they can be further processed into LDL. The clearance of VLDL and its remnants is critical for maintaining plasma lipid homeostasis, and impaired clearance contributes to dyslipidemia. Apolipoprotein E (APOE) on the VLDL surface serves as a ligand for hepatic receptors, facilitating this clearance.
Key Genes Involved in GO:0034361 very-low-density lipoprotein particle
The following genes and their protein products are key players in the biology of the very-low-density lipoprotein particle.
| Gene | Major Role | Research Relevance |
|---|---|---|
| APOB | Structural apolipoprotein of VLDL; essential for assembly and secretion | Mutations cause familial hypobetalipoproteinemia; target for KO and knock-in models |
| APOE | Surface apolipoprotein mediating receptor binding and clearance | Isoforms affect Alzheimer's and cardiovascular risk; KO models show impaired VLDL clearance |
| APOC1 | Inhibits lipoprotein lipase and hepatic lipase; modulates VLDL metabolism | Overexpression models show hypertriglyceridemia |
| APOC2 | Activates lipoprotein lipase | Deficiency causes hypertriglyceridemia; KO models mimic human disease |
| APOC3 | Inhibits lipoprotein lipase and hepatic uptake of remnants | Loss-of-function mutations lower triglycerides; target for CRISPR KO |
| MTTP | Lipidates APOB100 during VLDL assembly | Deficiency causes abetalipoproteinemia; essential for VLDL production |
| LPL | Hydrolyzes VLDL triglycerides for tissue uptake | Deficiency causes hypertriglyceridemia; KO models are hypertriglyceridemic |
| LDLR | Mediates clearance of VLDL remnants and LDL | Mutations cause familial hypercholesterolemia; KO models are hypercholesterolemic |
| PCSK9 | Promotes LDL receptor degradation | Inhibitors lower LDL; KO models show increased LDL clearance |
| ANGPTL3 | Inhibits lipoprotein lipase and endothelial lipase | Loss-of-function lowers triglycerides; CRISPR KO models are hypolipidemic |
| ANGPTL4 | Inhibits lipoprotein lipase | KO models show altered triglyceride metabolism |
| CREBH | Transcription factor regulating VLDL secretion | KO models show reduced VLDL secretion |
| FOXO1 | Transcription factor promoting VLDL secretion in insulin resistance | Overexpression models show increased VLDL |
| SREBP-1c | Transcription factor activating lipogenic genes | Overexpression models show fatty liver and VLDL overproduction |
| PPARα | Nuclear receptor regulating lipid oxidation and VLDL production | Agonists lower triglycerides; KO models show dyslipidemia |
| INSIG | Regulates SREBP processing and lipogenesis | KO models show increased lipogenesis and VLDL secretion |
| DGAT1 | Catalyzes the final step of triglyceride synthesis | KO models show reduced VLDL secretion |
| DGAT2 | Catalyzes triglyceride synthesis for VLDL | KO models show impaired VLDL production |
How Is very-low-density lipoprotein particle Regulated?
VLDL assembly and secretion are tightly regulated at multiple levels. Transcriptional regulation involves nuclear receptors such as PPARα and transcription factors like SREBP-1c and FOXO1, which respond to nutritional and hormonal signals. Insulin resistance promotes VLDL overproduction through increased expression of lipogenic genes and enhanced secretion. Post-translational regulation includes the activity of MTTP and the availability of lipids for lipidation. Additionally, apolipoproteins such as APOC3 and ANGPTL3 modulate VLDL clearance by inhibiting lipoprotein lipase.
very-low-density lipoprotein particle and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| APOB | Familial hypobetalipoproteinemia; cardiovascular risk | KO and knock-in models in HepG2 or primary hepatocytes |
| APOE | Alzheimer's disease; dyslipidemia | APOE KO and humanized knock-in mice |
| LDLR | Familial hypercholesterolemia | LDLR KO mice and cell lines |
| PCSK9 | Hypercholesterolemia | PCSK9 KO and overexpression models |
| ANGPTL3 | Hypertriglyceridemia; cardiovascular risk | ANGPTL3 KO mice and hepatocyte models |
Diabetic Dyslipidemia and Insulin Resistance
Insulin resistance is a major driver of VLDL overproduction, leading to diabetic dyslipidemia characterized by elevated triglycerides and small dense LDL particles. The mechanisms involve increased hepatic lipogenesis, reduced apolipoprotein B degradation, and enhanced VLDL secretion. This condition significantly increases cardiovascular risk in patients with type 2 diabetes.
Cardiovascular Disease and Atherosclerosis
Elevated levels of apolipoprotein B-containing lipoproteins, including VLDL and its remnants, are causally linked to coronary artery disease. The size, type, and count of these lipoproteins influence atherogenesis, with smaller and denser particles being more atherogenic. Targeting VLDL metabolism is a key strategy for cardiovascular risk reduction.
Familial Hypercholesterolemia and Genetic Dyslipidemias
Mutations in genes affecting VLDL clearance, such as LDLR and APOE, lead to familial hypercholesterolemia and other genetic dyslipidemias. These conditions are characterized by elevated LDL and remnants, and they serve as models for studying VLDL metabolism.
From very-low-density lipoprotein particle-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| What is the role of APOB in VLDL assembly? | APOB knockout hepatocytes (e.g., HepG2) |
| How does APOE isoform affect VLDL clearance? | APOE knock-in mice expressing human isoforms |
| Does ANGPTL3 inhibition lower VLDL? | ANGPTL3 knockout mouse model |
| What is the effect of PCSK9 on VLDL metabolism? | PCSK9 overexpression in hepatocytes |
| How does MTTP deficiency affect VLDL secretion? | MTTP knockout cell lines |
| Can CRISPR correct a dyslipidemia-causing mutation? | Patient-derived iPSCs with point mutation correction |
How to Study the very-low-density lipoprotein particle Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Ultracentrifugation | Lipoprotein density fractions | Isolation of VLDL from plasma |
| Mass-sensitive biosensor | VLDL concentration | Direct assessment in clinical samples |
| Stable isotope kinetics | Apolipoprotein B turnover | Human VLDL metabolism studies |
| CRISPR-Cas9 knockout | Gene function | Identifying genes required for VLDL assembly |
| RNA-seq | Transcriptional changes | Analyzing lipogenic gene expression |
| Proteomics | Apolipoprotein composition | Characterizing VLDL particles |
| Lipidomics | Lipid species profiling | Quantifying triglycerides and cholesterol |
| Live-cell imaging | VLDL trafficking | Visualizing secretion dynamics |
Lipoprotein Profiling and Quantification
VLDL particles can be quantified using ultracentrifugation, gel electrophoresis, and mass-sensitive biosensors. A molecularly imprinted polymer-based sensor has been developed for direct assessment of VLDL. Apolipoprotein B metabolism can be studied using stable isotope kinetic studies in humans.
Genetic and Genomic Approaches
CRISPR-Cas9 genome editing enables the creation of knockout, knock-in, and point-mutation models to study genes involved in VLDL metabolism. Transcriptomic analysis (RNA-seq) can reveal changes in gene expression associated with VLDL overproduction.
Proteomic and Lipidomic Analysis
Mass spectrometry-based proteomics can identify apolipoprotein composition of VLDL, while lipidomics quantifies triglyceride and cholesterol species. These methods are essential for understanding VLDL heterogeneity.
Cell Biology and Imaging
Fluorescence microscopy and live-cell imaging can track VLDL assembly and secretion in hepatocytes. Co-localization studies with ER and Golgi markers reveal the secretory pathway.
How CRISPR Can Be Used to Study GO:0034361 very-low-density lipoprotein particle
Knockout
CRISPR-Cas9 knockout of genes such as APOB, MTTP, or ANGPTL3 in hepatocyte cell lines or mouse models can elucidate their essential roles in VLDL assembly and secretion. For example, APOB knockout abolishes VLDL production, confirming its structural requirement.
Point Mutation
Introducing disease-associated point mutations (e.g., in APOE or LDLR) using CRISPR base editing or homology-directed repair allows researchers to study the functional impact of specific variants on VLDL metabolism.
Knock-in
Knock-in of human APOE isoforms or APOC3 variants into mouse models enables the study of human-relevant VLDL biology and drug responses.
Overexpression
CRISPR activation (CRISPRa) or lentiviral overexpression of genes like SREBP-1c or FOXO1 can mimic insulin-resistant states with VLDL overproduction, providing models for drug screening.
How EDITGENE Supports very-low-density lipoprotein particle Research
Researchers studying very-low-density lipoprotein particle-related genes often need to determine whether a candidate gene is causally involved in VLDL assembly, secretion, or clearance. EDITGENE provides comprehensive CRISPR-based services to create precisely engineered cell and animal models, enabling functional validation of genes implicated in VLDL biology.
Contact EDITGENE today to design your custom CRISPR model for very-low-density lipoprotein particle research.
Frequently Asked Questions About very-low-density lipoprotein particle
What is very-low-density lipoprotein particle?
It is a triglyceride-rich lipoprotein complex, defined by GO:0034361, that transports endogenous lipids from the liver to peripheral tissues.
What genes are involved in very-low-density lipoprotein particle?
Key genes include APOB, APOE, APOC1, APOC2, APOC3, MTTP, LPL, LDLR, PCSK9, and ANGPTL3.
What is the function of VLDL?
VLDL delivers triglycerides and cholesterol from the liver to muscles and adipose tissue for energy and storage.
How is VLDL assembled?
VLDL is assembled in the liver through lipidation of APOB100 by MTTP, followed by secretion.
What diseases are associated with VLDL?
VLDL overproduction is linked to diabetic dyslipidemia, insulin resistance, and cardiovascular disease.
Why is apolipoprotein B a better marker than LDL cholesterol?
ApoB reflects the total number of atherogenic particles, including VLDL remnants, and is a stronger predictor of cardiovascular risk.
Can CRISPR be used to study VLDL?
Yes, CRISPR knockout, knock-in, and point mutation models are powerful tools to study genes involved in VLDL metabolism.
What is the density of VLDL?
VLDL has a density of approximately 1.006 g/ml.
What is the size of VLDL?
VLDL particles range from 20 to 80 nm in diameter.
How can VLDL be measured?
VLDL can be measured by ultracentrifugation, gel electrophoresis, or mass-sensitive biosensors.
Conclusion
The very-low-density lipoprotein particle (GO:0034361) is a central player in lipid homeostasis, with critical roles in energy distribution and cardiovascular health. Its complex assembly, regulation, and metabolism are areas of intense research, and CRISPR-based models offer powerful tools to dissect these processes. Understanding VLDL biology is essential for developing new therapies for dyslipidemia and atherosclerosis.
References
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- 3. van Zwol W et al.. 2024. VLDL Biogenesis and Secretion: It Takes a Village.. Circ Res 134(2):226-244 PMID: 38236950
- 4. Chunta S et al.. 2021. Direct assessment of very-low-density lipoprotein by mass sensitive sensor with molecularly imprinted polymers.. Talanta 221:121549 PMID: 33076107
- 5. Demant T et al.. 1988. Very low density lipoprotein apolipoprotein B metabolism in humans.. Klin Wochenschr 66(16):703-12 PMID: 3050267
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