The Physiological Role of Lipoprotein (a)

Area of Science:

• Cardiovascular Biology
• Lipid Metabolism
• Proteomics

Background:

• Lipoprotein (a) [Lp(a)] is a highly atherogenic lipoprotein.
• The physiological function and metabolism of Lp(a) are not fully understood.
• Apolipoprotein a [apo(a)] size influences Lp(a) synthesis and excretion.

Purpose of the Study:

• To elucidate the metabolic pathway of Lipoprotein (a) [Lp(a)].
• To identify potential therapeutic targets for reducing atherogenic Lp(a).

Main Methods:

• Proposed a model for Lp(a) metabolism based on existing and new data.
• Described the binding of apo(a) to LDL via kringle IV domains.
• Detailed the stabilization of Lp(a) by disulfide bridges and its interaction with kidney cells.

Main Results:

• Apo(a) is synthesized in liver cells, with isoform size affecting its production and release.
• Lp(a) assembly involves apo(a) binding to LDL, stabilized by a disulfide bond.
• Kidney cells cleave apo(a), producing fragments that may be the active atherogenic form.

Conclusions:

• Lp(a) metabolism involves hepatic synthesis, LDL binding, and renal cleavage.
• Apo(a) fragments generated by protease action may be responsible for Lp(a)'s atherogenicity.
• Therapeutic strategies should target Lp(a) assembly or apo(a) fragmentation.