ANGPTL3 is a novel HDL component that regulates HDL function.

Area of Science:

• Cardiovascular Biology
• Lipid Metabolism
• Protein Biochemistry

Background:

• Angiopoietin-like protein 3 (ANGPTL3) is known to inhibit lipase activity and correlate with high-density lipoprotein (HDL) levels.
• Recent findings indicate ANGPTL3 preferentially binds to HDL in healthy individuals.
• The role of ANGPTL3 as an HDL component modulating HDL function, particularly in diabetes, requires further investigation.

Purpose of the Study:

• To investigate whether ANGPTL3, as a component of HDL, modulates HDL function and affects other HDL components.
• To examine the role of ANGPTL3 in HDL function in both non-diabetic and type 2 diabetes mellitus (T2DM) contexts in humans and mice.

Main Methods:

• HDL isolation from non-diabetic and T2DM subjects and mice.
• Assays including immunoprecipitation, western blot, and ELISA to quantify ANGPTL3 levels in HDL.
• In vivo studies using mouse models (db/m, db/db, ANGPTL3 knockout, AAV-mediated overexpression/knockdown) to assess HDL cholesterol efflux and anti-inflammatory capacity.

Main Results:

• ANGPTL3 was confirmed as an HDL component in both non-diabetic and T2DM individuals and in mice.
• HDL-associated ANGPTL3 positively correlated with cholesterol efflux in non-diabetic controls but not in T2DM patients.
• ANGPTL3 deficiency or knockdown in mice reduced HDL cholesterol efflux and anti-inflammatory functions, while overexpression improved these functions.

Conclusions:

• ANGPTL3 is an integral component of HDL in humans and mice, influencing HDL's cholesterol efflux and anti-inflammatory properties.
• ANGPTL3 in HDL appears to regulate HDL function, potentially by altering the balance of its protein components, especially in the context of T2DM.
• This study enhances the understanding of ANGPTL3's multifaceted role in lipid metabolism and cardiovascular health.