GO:0034362 low-density lipoprotein particle: Components, Assembly and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0034362 defines the low-density lipoprotein (LDL) particle as a cholesterol-ester-rich, triglyceride-poor lipoprotein of 20-25 nm diameter and density 1.02-1.06 g/ml, typically containing APOB100 and APOE.
• LDL particles are derived from VLDL via IDL through triglyceride loss and cholesterol ester gain, and they transport endogenous cholesterol from peripheral tissues back to the liver.
• Small dense LDL (sdLDL) subfractions are more atherogenic than larger LDL particles and are associated with increased cardiovascular risk.
• LDL particle number and size are independent risk factors for cardiovascular disease and may also relate to cerebral amyloidosis.
• LDL particles can transfer cargo to biomembranes independently of classical receptors, and their fatty acid composition can undergo nitration, affecting function.
• Dietary fat consumption modulates LDL particle size, making it a modifiable research and clinical target.
Description
The low-density lipoprotein (LDL) particle (GO:0034362) is a central cellular component in lipid metabolism and cardiovascular biology. According to QuickGO, it is a lipoprotein particle rich in cholesterol esters and low in triglycerides, typically composed of APOB100 and APOE, with a density of 1.02-1.06 g/ml and a diameter of 20-25 nm. LDL particles are formed from VLDL particles via IDL by the loss of triglyceride and gain of cholesterol ester, and they transport endogenous cholesterol from peripheral tissues back to the liver. This term is essential for researchers studying atherosclerosis, dyslipidemia, and related metabolic disorders, as LDL particle composition and size are directly linked to atherogenicity. The clinical relevance of LDL particles extends beyond total cholesterol levels; particle number and size subfractions are independent predictors of cardiovascular events. Moreover, small dense LDL particles have been implicated in cerebral amyloidosis, suggesting a broader role in neurodegeneration. Understanding the molecular and cellular aspects of LDL particles is therefore critical for developing targeted therapies and diagnostic tools.
low-density lipoprotein particle At A Glance
| GO ID | GO:0034362 |
|---|---|
| GO term | low-density lipoprotein particle |
| Ontology | cellular_component |
| Synonym | LDL complex, LDL particle, low-density lipoprotein complex |
| Major function | Transport of endogenous cholesterol and triglycerides from peripheral tissues to the liver |
| Composition | Rich in cholesterol esters, low in triglycerides; typically contains APOB100 and APOE |
| Density | 1.02-1.06 g/ml |
| Diameter | 20-25 nm |
| Formation | Derived from VLDL via IDL by loss of triglyceride and gain of cholesterol ester |
What Is GO:0034362?
GO:0034362 describes the low-density lipoprotein particle as a spherical lipoprotein complex that is rich in cholesterol esters and low in triglycerides. It is typically composed of apolipoprotein B-100 (APOB100) and apolipoprotein E (APOE), with a density between 1.02 and 1.06 g/ml and a diameter of 20-25 nm. These particles are generated from VLDL particles through the intermediate IDL, undergoing triglyceride loss and cholesterol ester gain. Their primary function is to transport endogenous cholesterol, and to some extent triglycerides, from peripheral tissues back to the liver.
Why Is low-density lipoprotein particle Important in Cell Biology?
The LDL particle is a key player in lipid homeostasis and a major risk factor for cardiovascular disease. Elevated levels of LDL particles, particularly small dense LDL, are strongly associated with atherosclerosis and coronary artery disease. Beyond cardiovascular risk, LDL particles have been linked to cerebral amyloidosis, suggesting a role in Alzheimer's disease pathology. Their compositional complexity, including apolipoprotein content and lipid modifications such as fatty acid nitration, influences their atherogenic potential. Therefore, studying LDL particles is crucial for understanding the mechanisms of dyslipidemia, developing biomarkers, and designing therapeutic interventions.
• LDL particles are primary carriers of cholesterol and are central to atherogenesis.
• Small dense LDL subfractions are more atherogenic and predict cardiovascular events.
• LDL particle number is an independent risk factor for cardiovascular disease.
• LDL particles are implicated in cerebral amyloidosis and neurodegeneration.
• Receptor-independent transfer of LDL cargo to biomembranes reveals alternative uptake mechanisms.
• Fatty acid nitration in LDL can alter its function and contribute to oxidative stress.
• Dietary fat consumption affects LDL particle size, offering a modifiable risk factor.
• LDL particles are targets for lipid-lowering therapies and diagnostic assays.
What Happens During low-density lipoprotein particle?
Formation from VLDL via IDL
In simple terms: LDL particles are made from larger VLDL particles through a stepwise process.
LDL particles are formed from VLDL particles via intermediate-density lipoprotein (IDL) by the loss of triglyceride and gain of cholesterol ester. This maturation process involves the action of cholesteryl ester transfer protein (CETP) and hepatic lipase, although specific enzymes are not detailed in the provided citations. The resulting LDL particle is enriched in cholesterol esters and depleted in triglycerides, with a density of 1.02-1.06 g/ml and a diameter of 20-25 nm.
Cholesterol Transport
In simple terms: LDL particles carry cholesterol from tissues back to the liver.
The primary function of LDL particles is to transport endogenous cholesterol (and to some extent triglycerides) from peripheral tissues back to the liver. This transport is essential for maintaining cholesterol homeostasis. The particle typically contains APOB100 and APOE, which facilitate interactions with receptors and membranes.
Receptor-Independent Cargo Transfer
In simple terms: LDL particles can deliver their contents to cells without using classic receptors.
Recent studies have shown that LDL particles can transfer their cargo to biomembranes independently of classical LDL receptors. This mechanism may contribute to cholesterol delivery in tissues and has implications for understanding LDL metabolism beyond the canonical receptor-mediated pathway.
Fatty Acid Nitration
In simple terms: Fatty acids in LDL can be chemically modified, affecting their behavior.
Fatty acid nitration occurs in human LDL particles, leading to the formation of nitro-fatty acids. These modifications can alter LDL function and contribute to oxidative stress and inflammation, which are relevant to atherogenesis.
Key Genes Involved in GO:0034362 low-density lipoprotein particle
The following genes and proteins are key components or regulators of low-density lipoprotein particles, based on their established roles in lipoprotein metabolism and the provided literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| APOB | Primary apolipoprotein of LDL; ligand for LDL receptor | Mutations cause familial hypercholesterolemia; target for lipid-lowering therapies |
| APOE | Apolipoprotein component of LDL; involved in cholesterol transport | Isoforms affect Alzheimer's disease risk and lipid metabolism |
| LDLR | Receptor for LDL uptake | Defects cause familial hypercholesterolemia; target of statins |
| PCSK9 | Regulates LDL receptor degradation | Inhibitors lower LDL cholesterol; target for gene editing |
| CETP | Transfers cholesteryl esters between lipoproteins | Inhibition raises HDL and lowers LDL; cardiovascular outcomes |
| LPL | Hydrolyzes triglycerides in VLDL and chylomicrons | Deficiency causes hypertriglyceridemia; affects LDL formation |
| HL (LIPC) | Hepatic lipase; remodels lipoproteins | Polymorphisms affect LDL size and cardiovascular risk |
| ABCG5/ABCG8 | Plant sterol transporters | Mutations cause sitosterolemia; affect cholesterol absorption |
| NPC1L1 | Intestinal cholesterol absorption | Target of ezetimibe; affects LDL levels |
| SREBF2 | Master regulator of cholesterol synthesis | Feedback regulation of LDL receptor |
| HMGCR | Rate-limiting enzyme in cholesterol synthesis | Target of statins; affects LDL production |
| MTTP | Microsomal triglyceride transfer protein | Required for APOB lipidation; inhibitors lower LDL |
| ANGPTL3 | Inhibits lipoprotein lipase | Loss-of-function lowers LDL and triglycerides |
| APOC3 | Inhibits lipoprotein lipase and hepatic uptake | Loss-of-function lowers triglycerides and LDL |
| SCARB1 | HDL receptor; also binds LDL | Affects cholesterol transport and atherosclerosis |
| CYP7A1 | Cholesterol 7-alpha-hydroxylase | Regulates bile acid synthesis from cholesterol |
| NR1H2/NR1H3 | LXR nuclear receptors | Regulate cholesterol efflux and lipoprotein metabolism |
How Is low-density lipoprotein particle Regulated?
LDL particle metabolism is regulated at multiple levels. Cholesterol homeostasis is controlled by the SREBP-2 pathway, which senses cellular cholesterol levels and regulates LDL receptor expression. PCSK9 modulates LDL receptor recycling, and its inhibition increases LDL clearance. Additionally, dietary fat consumption influences LDL particle size, with high-fat diets associated with smaller, denser LDL particles. Hormonal and genetic factors also play roles, but specific regulatory mechanisms are beyond the scope of the provided citations.
low-density lipoprotein particle and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| LDLR | Familial hypercholesterolemia | LDLR knockout mouse; point mutation knock-in |
| APOB | Familial hypercholesterolemia; hypobetalipoproteinemia | APOB knockout or transgenic mice |
| PCSK9 | Hypercholesterolemia; cardiovascular risk | PCSK9 gain-of-function knock-in; knockout |
| APOE | Alzheimer's disease; dyslipidemia | APOE isoform knock-in mice (e.g., APOE4) |
| CETP | Cardiovascular disease; lipid levels | CETP transgenic mice; knockout |
Cardiovascular Disease
Elevated LDL particle number and small dense LDL subfractions are established risk factors for cardiovascular disease, including atherosclerosis and coronary artery disease. The atherogenicity of LDL particles is influenced by their composition, such as cholesterol ester content and apolipoprotein profile.
Neurodegeneration and Cerebral Amyloidosis
LDL particle size subfractions have been associated with cerebral amyloidosis, a hallmark of Alzheimer's disease. This suggests that LDL particles may contribute to amyloid-beta deposition or clearance, linking lipid metabolism to neurodegeneration.
Metabolic Disorders
Disorders of lipoprotein metabolism, such as familial hypercholesterolemia, involve defective LDL clearance and elevated LDL particles. Dietary factors, such as fat consumption, can modulate LDL particle size and influence metabolic risk.
From low-density lipoprotein particle-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Role of APOB in LDL particle assembly | APOB knockout hepatocytes or mice |
| Effect of PCSK9 mutations on LDL receptor degradation | PCSK9 point mutation knock-in cell lines |
| Impact of APOE isoforms on LDL metabolism | APOE knock-in mice (APOE2, APOE3, APOE4) |
| LDL receptor recycling and LDL uptake | LDLR knockout and tagged knock-in cells |
| CETP-mediated cholesterol ester transfer | CETP overexpression in cell models |
| Dietary fat effects on LDL particle size | Mouse models fed high-fat diets |
How to Study the low-density lipoprotein particle Process
| Method | What It Measures | Typical Application |
|---|---|---|
| NMR spectroscopy | LDL particle number and size | Cardiovascular risk assessment |
| Ultracentrifugation | LDL subfractions | Lipoprotein research |
| CRISPR knockout | Gene function in LDL metabolism | Target validation |
| RNA-seq | Transcriptional changes | Pathway analysis |
| Proteomics | Apolipoprotein composition | Biomarker discovery |
| Lipidomics | Cholesterol ester and triglyceride content | LDL composition analysis |
| Fluorescence microscopy | LDL uptake and trafficking | Mechanistic studies |
Lipoprotein Profiling
Analytical methods such as nuclear magnetic resonance (NMR) spectroscopy and ultracentrifugation are used to measure LDL particle number and size subfractions. These techniques are critical for assessing cardiovascular risk beyond standard lipid panels.
Genetic and Genomic Approaches
Genome-wide association studies and candidate gene approaches have identified variants in genes such as APOB, LDLR, and PCSK9 that influence LDL particle levels. CRISPR screening can further dissect gene function in lipoprotein metabolism.
Imaging and Cellular Assays
Fluorescence microscopy and biochemical assays can visualize LDL particle uptake and cargo transfer to biomembranes. These methods help elucidate receptor-independent mechanisms.
Lipidomics and Proteomics
Mass spectrometry-based lipidomics and proteomics can characterize LDL particle composition, including fatty acid nitration and apolipoprotein content. Such analyses reveal modifications that affect atherogenicity.
How CRISPR Can Be Used to Study GO:0034362 low-density lipoprotein particle
Knockout
CRISPR knockout of genes such as LDLR, APOB, or PCSK9 in cell models can elucidate their roles in LDL particle formation, uptake, and metabolism. For example, LDLR knockout cells are used to study familial hypercholesterolemia.
Point Mutation
Introducing point mutations (e.g., in PCSK9 or APOE) via CRISPR can model human variants associated with dyslipidemia or Alzheimer's disease. These models help assess the functional impact of specific alleles.
Knock-in
Knock-in of tagged APOB or APOE allows tracking of LDL particles in live cells and tissues. This approach is valuable for studying particle trafficking and interactions.
Overexpression
Overexpression of CETP or APOC3 in cell or animal models can mimic dyslipidemic states and test therapeutic interventions. CRISPR activation (CRISPRa) can achieve targeted overexpression.
How EDITGENE Supports low-density lipoprotein particle Research
Researchers studying low-density lipoprotein particle-related genes often need to determine whether a candidate gene is causally involved in lipoprotein metabolism, cardiovascular risk, or neurodegeneration. EDITGENE provides comprehensive CRISPR-based services to create precise cell and animal models for such investigations.
Contact EDITGENE today to design your custom CRISPR model for low-density lipoprotein particle research.
Frequently Asked Questions About low-density lipoprotein particle
What is GO:0034362?
GO:0034362 is the Gene Ontology term for low-density lipoprotein particle, a cholesterol-rich lipoprotein complex involved in lipid transport.
What genes are involved in low-density lipoprotein particle?
Key genes include APOB, APOE, LDLR, PCSK9, and CETP, among others.
What is the function of low-density lipoprotein particle?
It transports endogenous cholesterol from peripheral tissues back to the liver.
How is low-density lipoprotein particle formed?
It is formed from VLDL via IDL by losing triglycerides and gaining cholesterol esters.
What diseases are associated with low-density lipoprotein particle?
Cardiovascular disease, atherosclerosis, and cerebral amyloidosis are linked to LDL particles.
What is small dense LDL?
Small dense LDL is a subfraction of LDL particles that is more atherogenic and associated with higher cardiovascular risk.
Can diet affect LDL particle size?
Yes, dietary fat consumption can influence LDL particle size, with high-fat diets associated with smaller particles.
How can I study LDL particles in the lab?
Methods include NMR, ultracentrifugation, CRISPR knockout, and lipidomics.
What CRISPR models are available for LDL research?
Knockout, point mutation, knock-in, and overexpression models can be generated for genes like LDLR and PCSK9.
Why is LDL particle number important?
LDL particle number is an independent risk factor for cardiovascular disease, beyond LDL cholesterol levels.
Conclusion
The low-density lipoprotein particle (GO:0034362) is a fundamental component of lipid metabolism with profound implications for cardiovascular and neurodegenerative diseases. Its composition, size, and number are critical determinants of atherogenicity and clinical risk. Continued research using advanced CRISPR models and analytical techniques will further elucidate its biology and pave the way for novel therapies.
References
- 1. Rudel LL et al.. 2000. Low-density lipoprotein particle composition: what is the contribution to atherogenicity?. Curr Opin Lipidol 11(3):227-8 PMID: 10882336
- 2. Hernando-Redondo J et al.. 2025. Atherogenic low-density lipoprotein and cardiovascular risk.. Curr Opin Lipidol 36(1):8-13 PMID: 39641158
- 3. Kanonidou C. 2021. Small dense low-density lipoprotein: Analytical review.. Clin Chim Acta 520:172-178 PMID: 34118239
- 4. Lee S et al.. 2019. Low-Density Lipoprotein Particle Size Subfractions and Cerebral Amyloidosis.. J Alzheimers Dis 68(3):983-990 PMID: 30883362
- 5. Cromwell WC et al.. 2004. Low-density lipoprotein particle number and risk for cardiovascular disease.. Curr Atheroscler Rep 6(5):381-7 PMID: 15296705
- 6. Axmann M et al.. 2019. Receptor-Independent Transfer of Low Density Lipoprotein Cargo to Biomembranes.. Nano Lett 19(4):2562-2567 PMID: 30848605
- 7. Mastrogiovanni M et al.. 2020. Fatty acid nitration in human low-density lipoprotein.. Arch Biochem Biophys 679:108190 PMID: 31738891
- 8. Froyen E. 2021. The effects of fat consumption on low-density lipoprotein particle size in healthy individuals: a narrative review.. Lipids Health Dis 20(1):86 PMID: 34362390
