ApoA-I Mimetic Peptide 4F Reduces Age-Related Lipid Deposition in Murine Bruch's Membrane and Causes Its Structural Remodeling

Curr Eye Res. 2018 Jan;43(1):135-146. doi: 10.1080/02713683.2017.1370118. Epub 2017 Oct 3.

Abstract

Purpose: Accumulation of lipoprotein-derived lipids including esterified and unesterified cholesterol in Bruch's membrane of human eyes is a major age-related change involved in initiating and sustaining soft drusen in age-related macular degeneration (AMD). The apolipoprotein (apo) A-I mimetic peptide 4F is a small anti-inflammatory and anti-atherogenic agent, and potent modifier of plasma membranes. We evaluated the effect of intravitreally-injected 4F on murine Bruch's membrane.

Methods: We tested single intravitreal injections of 4F doses (0.6 µg, 1.2 µg, 2.4 µg, and placebo scrambled peptide) in ApoEnull mice ≥10 months of age. After 30 days, mice were euthanized. Eyes were processed for either direct immunofluorescence detection of esterified cholesterol (EC) in Bruch's membrane whole mounts via a perfringolysin O-based marker linked to green fluorescent protein or by transmission electron microscopic visualization of Bruch's membrane integrity. Fluorescein isothiocyanate-conjugated 4F was traced after injection.

Results: All injected eyes showed a dose-dependent reduction of Bruch's membrane EC with a concomitant ultrastructural improvement compared to placebo treated eyes. At a 2.4 µg dose of 4F, EC was reduced on average by ~60% and Bruch's membrane returned to a regular pentalaminar structure and thickness. Tracer studies confirmed that injected 4F reached intraocular targets.

Conclusion: We demonstrated a highly effective pharmacological reduction of EC and restoration of Bruch's membrane ultrastructure. The apoA-I mimetic peptide 4F is a novel way to treat a critical AMD disease process and thus represents a new candidate for treating the underlying cause of AMD.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bruch Membrane / drug effects
  • Bruch Membrane / metabolism*
  • Bruch Membrane / ultrastructure
  • Intravitreal Injections
  • Lipids*
  • Macular Degeneration / drug therapy*
  • Macular Degeneration / metabolism
  • Macular Degeneration / pathology
  • Mice
  • Microscopy, Electron, Transmission
  • Peptides / administration & dosage
  • Peptides / pharmacokinetics*
  • Pigment Epithelium of Eye / drug effects
  • Pigment Epithelium of Eye / metabolism
  • Pigment Epithelium of Eye / ultrastructure

Substances

  • Lipids
  • Peptides
  • apolipoprotein A-I mimetic peptide 4F