The N-terminus of Apolipoprotein B mediates the interaction of atherogenic lipoproteins with endothelial cells.

Summary

Distinct N-terminal domains of ApoB mediate endothelial uptake of atherogenic lipoproteins via SR-BI and ALK1. An 18% N-terminal fragment (ApoB18) inhibits endothelial transport of chylomicrons and LDL and reduces atherosclerosis in hypercholesterolemic mice, suggesting a receptor-blocking decoy strategy to prevent vascular lipid entry.

Key Findings

• Different ApoB N-terminal regions interact with endothelial SR-BI and ALK1 to mediate chylomicron and LDL uptake.
• ApoB48 lipoproteins are internalized only via SR-BI, highlighting receptor specificity.
• ApoB18 fragment reduces endothelial uptake/transport of both chylomicrons and LDL and decreases atherosclerosis in hypercholesterolemic mice.
• A shorter fragment (ApoB12) selectively blocks ALK1-mediated uptake of ApoB100 lipoproteins.

Clinical Implications

Therapeutics that block ApoB N-terminus interactions (e.g., ApoB18-mimetic peptides/biologics) could complement statins/PCSK9 inhibitors by preventing endothelial lipoprotein transcytosis; biomarker-guided selection may focus on high TRL/LDL flux phenotypes.

Limitations

• Translational applicability of ApoB18 delivery, dosing, and long-term safety remains untested in humans.
• Abstract does not detail sample sizes or potential off-target effects of fragments.

Future Directions

Develop ApoB18-mimetics with optimized pharmacokinetics; evaluate combination with LDL-lowering agents; quantify endothelial transcytosis reduction and plaque effects in large-animal models before first-in-human studies.