Apolipoprotein-AI mimetic peptides D-4F and L-5F decrease hepatic inflammation and increase insulin sensitivity in...

Area of Science:

• Metabolic disease research
• Molecular biology
• Pharmacology

Background:

• Apolipoprotein-AI (apo-AI) is crucial for high-density lipoprotein (HDL) function.
• Previous studies showed apo-AI improves insulin sensitivity and reduces hepatic inflammation.
• Apo-AI mimetic peptides offer a more clinically feasible therapeutic approach.

Purpose of the Study:

• To evaluate if apo-AI mimetic peptides (D-4F and L-5F) can replicate the insulin-sensitizing effects of full-length apo-AI.
• To assess the impact of these peptides on insulin resistance in a high-fat diet mouse model.

Main Methods:

• Male C57BL/6 mice were fed a high-fat diet for 16 weeks.
• Mice received D-4F or L-5F peptides via drinking water or intraperitoneal injection.
• Glucose and insulin tolerance tests were performed, alongside real-time PCR analysis of key metabolic and inflammatory genes.

Main Results:

• Both D-4F and L-5F peptides improved glucose and insulin tolerance.
• Peptide treatment significantly decreased hepatic inflammation markers (SAA1, IL-1β, IFN-γ, TNFα).
• Gene expression analysis revealed suppression of gluconeogenesis and lipogenesis pathways, and reduced macrophage infiltration.

Conclusions:

• Apo-AI mimetic peptides effectively improve glucose homeostasis in a high-fat diet model.
• The observed benefits are linked to reduced hepatic inflammation and suppressed gluconeogenic and lipogenic gene expression.
• These peptides represent a potential therapeutic strategy for overnutrition-induced insulin resistance.