Targeting cholesteryl ester accumulation in the heart improves cardiac insulin response

Area of Science:

• Cardiovascular Biology
• Metabolic Regulation
• Immunology

Background:

• Low-density lipoprotein receptor 1 (LRP1) regulates insulin receptor (InsR) trafficking.
• Cholesteryl ester (CE) accumulation in vascular cells is blocked by antibodies against LRP1's P3 sequence.
• The relationship between CE accumulation and insulin response is not well understood.

Purpose of the Study:

• To investigate the impact of P3 peptide immunization on cardiac insulin response alterations induced by a high-fat diet (HFD).
• To determine if targeting LRP1's P3 sequence can mitigate HFD-induced cardiac metabolic dysfunction.

Main Methods:

• Rabbits were immunized with P3 peptide or an irrelevant peptide and fed either HFD or normal chow.
• Cardiac lipid content was analyzed using chromatography and microscopy.
• LRP1, InsR, and GLUT4 levels, protein interactions, insulin signaling, and glucose uptake were assessed.

Main Results:

• HFD reduced cardiac InsR and GLUT4 membrane levels and LRP1/InsR interactions.
• Anti-P3 antibodies reduced cardiac CE accumulation and restored InsR, GLUT4, and LRP1/InsR interactions in HFD-fed rabbits.
• Anti-P3 antibodies improved insulin signaling and glucose uptake in cell models exposed to hypercholesterolemic serum.

Conclusions:

• LRP1 immunotargeting effectively blocks cardiac CE accumulation, enhancing the cardiac insulin response.
• This strategy holds therapeutic promise for various cardiac diseases associated with metabolic dysfunction.