Proteomic Determinants of Variation in Cholesterol Efflux: Observations from the Dallas Heart Study

Area of Science:

• Cardiovascular Biology
• Proteomics
• Lipid Metabolism

Background:

• High-density lipoproteins (HDL) are crucial for removing excess cholesterol from macrophages, a key process in preventing atherosclerotic cardiovascular disease (ASCVD).
• HDL's functional capacity, known as cholesterol efflux capacity (CEC), is inversely linked to ASCVD risk.
• The diverse protein composition of HDL and its impact on CEC are not fully understood.

Purpose of the Study:

• To identify and characterize specific HDL-associated proteins that modulate cholesterol efflux capacity (CEC) in humans.
• To define the role of different HDL subspecies in mediating cholesterol removal.

Main Methods:

• Proteomic analysis of plasma HDL was performed on individuals with persistently extremely high or low CEC over 15 years from the Dallas Heart Study (DHS) cohort.
• Statistical analysis, including correlation and heterogeneity testing, was used to assess the association between HDL protein levels and CEC.
• Differential protein enrichment on HDL subspecies was examined in relation to CEC.

Main Results:

• Levels of apolipoprotein (Apo)A-I associated proteins ApoC-II, ApoC-III, and ApoA-IV showed differential correlations with CEC in high versus low CEC groups.
• Specific proteins, including ApoC-III, complement C3 (CO3), ApoE, and plasminogen (PLMG), were inversely associated with CEC when present on HDL subspecies.
• HDL subspecies lacking these specific proteins exhibited significantly higher CEC.

Conclusions:

• The enrichment of particular proteins on distinct HDL subspecies differentially regulates the capacity for cholesterol removal from the vasculature.
• These findings highlight the importance of HDL composition in determining its functional role in cardiovascular health.
• Targeting specific HDL subspecies based on their protein content may offer novel therapeutic strategies for ASCVD.