Immunometabolic modulation of retinal inflammation by CD36 ligand

Sci Rep. 2019 Sep 9;9(1):12903. doi: 10.1038/s41598-019-49472-8.

Abstract

In subretinal inflammation, activated mononuclear phagocytes (MP) play a key role in the progression of retinopathies. Little is known about the mechanism involved in the loss of photoreceptors leading to vision impairment. Studying retinal damage induced by photo-oxidative stress, we observed that cluster of differentiation 36 (CD36)-deficient mice featured less subretinal MP accumulation and attenuated photoreceptor degeneration. Moreover, treatment with a CD36-selective azapeptide ligand (MPE-001) reduced subretinal activated MP accumulation in wild type mice and preserved photoreceptor layers and function as assessed by electroretinography in a CD36-dependent manner. The azapeptide modulated the transcriptome of subretinal activated MP by reducing pro-inflammatory markers. In isolated MP, MPE-001 induced dissociation of the CD36-Toll-like receptor 2 (TLR2) oligomeric complex, decreasing nuclear factor-kappa B (NF-κB) and NLR family pyrin domain containing 3 (NLRP3) inflammasome activation. In addition, MPE-001 caused an aerobic metabolic shift in activated MP, involving peroxisome proliferator-activated receptor-γ (PPAR-γ) activation, which in turn mitigated inflammation. Accordingly, PPAR-γ inhibition blocked the cytoprotective effect of MPE-001 on photoreceptor apoptosis elicited by activated MP. By altering activated MP metabolism, MPE-001 decreased immune responses to alleviate subsequent inflammation-dependent neuronal injury characteristic of various vision-threatening retinal disorders.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biomarkers
  • CD36 Antigens / metabolism*
  • Cytokines / metabolism
  • Disease Susceptibility
  • Energy Metabolism / drug effects*
  • Immunomodulation / drug effects*
  • Inflammasomes / metabolism
  • Inflammation Mediators / metabolism
  • Ligands
  • Metabolome
  • Metabolomics / methods
  • Mice
  • NLR Family, Pyrin Domain-Containing 3 Protein / metabolism
  • Photoreceptor Cells, Vertebrate / metabolism
  • Photoreceptor Cells, Vertebrate / pathology
  • Protein Binding
  • Retinitis / etiology*
  • Retinitis / metabolism*
  • Retinitis / pathology
  • Signal Transduction / drug effects
  • Toll-Like Receptor 2 / metabolism

Substances

  • Biomarkers
  • CD36 Antigens
  • Cytokines
  • Inflammasomes
  • Inflammation Mediators
  • Ligands
  • NLR Family, Pyrin Domain-Containing 3 Protein
  • Toll-Like Receptor 2

Grants and funding