Coronary artery disease and cardiovascular diseases are the leading cause of death in most countries. Clinical CAD events are related to plaque instability due to lipid content and activity within the atherosclerotic plaque. Although subendothelial low-density lipoprotein (LDL) deposition is the hallmark of atherosclerosis, extensive lowering plasma LDL cholesterol (LDL-C) does not prevent cardiovascular events in all patients. Thus, it is important to identify atherogenic lipoproteins whose abundance and toxicity may not be sufficiently represented by the LDL-C values. Aside from the well-described oxidized LDL and small dense LDL, electronegative LDL (L5) and electronegative VLDL (V5) have also emerged as very likely atherogenic entities. Using anion-exchange chromatography, we have resolved LDL and VLDL into five subfractions with increasing electronegativity, L1–L5 and V1–V5 respectively. Unique in protein and lipid composition, L5 and V5 are internalized by lectin-like oxidized LDL receptor-1 (LOX-1) but not by normal LDL receptor or VLDL receptor. In different cultured cell lines, L5, exclusively among L1–L5, induces a wide spectrum of atherogenic responses. Less than 1% in normal healthy subjects, L5 in total LDL (L5/LDL%) is significantly increased in smokers, familial hyperlipidemia, metabolic syndrome (MetS), diabetes and ST-elevation myocardial infarction (STEMI) irrespective of LDL-C levels. More recently, charge-defined VLDL subfractions in MetS are determined to correlate electronegativity with increasing cytotoxicity to the vascular endothelium. These consistent patterns of elevated electronegative lipoprotein levels emerged in patients with cardiovascular risks have suggested that the index of electronegativity represents a novel predictor of atherosclerosis. However, these studies need to increase sample sizes and power. Detail pathological mechanisms need to be further elucidated among major organs. In this project, we will develop a multiple functional platform for lipoprotein research, including:
- Quantification services for electronegative lipoproteins:
we will set up a rapid diagnostic procedure for daily usage and for large-scale epidemiological survey. By decreasing the amount of blood sample, we will shorten the procedure and decrease the cost of testing.
- Purification of electronegative lipoproteins:
we will isolate and purify lipoproteins which are essential for each sub-project, including LDL, L1–L5, VLDL, V1–V5, HDL and H1–H5.
- Detection of lipoprotein components and antigenic epitopes:
By using LC/MSE, we will quantify protein composition and detect post-translational modifications.
- Detection of lipid moieties in electronegative lipoproteins:
We will extract total lipids, neutral lipids, phospholipids and free fatty acids from lipoproteins. By using LC/MSE, we will identify atherogenic lipid contents and their metabolites.
- Prediction of protein 3D structure and the simulation of molecular dynamics:
Predict protein 3D structure, analyze molecular dynamics and interactions.
- Consulting Services for Animal Studies:
we will share experiences, strategies and techniques for animal study. We’ll have high-fat-diet hamster for intrinsic high-electronegative lipoproteins, extrinsic lipoprotein-injected mice and gene deficiency mice.