very-low-density lipoprotein particle remodeling

Definition

Target type: biologicalprocess

The acquisition, loss or modification of a protein or lipid within a very-low-density lipoprotein particle, including the hydrolysis of triglyceride by hepatic lipase or lipoprotein lipase and the subsequent loss of free fatty acid. [GOC:BHF, GOC:expert_pt, GOC:mah, GOC:rl]

Very-low-density lipoprotein (VLDL) particle remodeling is a complex process that involves the transformation of VLDL particles into smaller, denser particles, primarily low-density lipoprotein (LDL) and high-density lipoprotein (HDL). It occurs in the bloodstream and involves various enzymes, proteins, and lipid components.

**Step 1: VLDL Secretion from Liver:**
VLDL is synthesized and secreted by the liver, containing primarily triglycerides, cholesterol esters, and apolipoproteins, including apoB-100, apoE, and apoC-II.

**Step 2: Triglyceride Hydrolysis:**
In the bloodstream, lipoprotein lipase (LPL), an enzyme attached to capillary walls, hydrolyzes triglycerides in VLDL particles, releasing free fatty acids. This process reduces VLDL size and increases its density.

**Step 3: Cholesterol Ester Transfer Protein (CETP) Activity:**
CETP facilitates the transfer of cholesterol esters from VLDL to HDL, enriching HDL with cholesterol and reducing VLDL cholesterol content. This exchange contributes to the further reduction in VLDL size.

**Step 4: Formation of Intermediate Density Lipoproteins (IDL):**
As VLDL loses triglycerides, it becomes denser and transforms into IDL particles. IDLs are smaller and denser than VLDL, but still contain significant amounts of triglycerides and cholesterol.

**Step 5: IDL Metabolism:**
IDLs can be further metabolized through two pathways:
- **Catabolism:** IDL can be taken up by the liver directly, where its cholesterol esters are hydrolyzed and cholesterol is released.
- **Conversion to LDL:** IDL can undergo additional lipolysis and removal of triglycerides, converting into LDL particles.

**Step 6: LDL Formation:**
LDL, the primary cholesterol carrier in the blood, is formed from IDL through further triglyceride hydrolysis and enrichment with cholesterol esters.

**Step 7: HDL Metabolism:**
HDL particles, enriched with cholesterol from VLDL and IDL, can either be taken up by the liver (reverse cholesterol transport) or interact with other lipoproteins, continuing the cholesterol transfer process.

The entire process of VLDL remodeling is tightly regulated by various factors, including dietary fat intake, genetic predisposition, and hormonal influences. Dysregulation of this process can contribute to the development of cardiovascular disease by increasing LDL levels and decreasing HDL levels in the blood.'
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Proteins (4)

Compounds (21)