Microglia lacking E Prostanoid Receptor subtype 2 have enhanced Abeta phagocytosis yet lack Abeta-activated neurotoxicity

Am J Pathol. 2005 Apr;166(4):1163-72. doi: 10.1016/s0002-9440(10)62336-x.

Abstract

Experimental therapies for Alzheimer's disease (AD) are focused on enhanced clearance of neurotoxic Abeta peptides from brain. Microglia can be neuroprotective by phagocytosing Abeta; however, this comes at the cost of activated innate immunity that causes paracrine damage to neurons. Here, we show that ablation of E prostanoid receptor subtype 2 (EP2) significantly increased microglial-mediated clearance of Abeta peptides from AD brain sections and enhanced microglial Abeta phagocytosis in cell culture. The enhanced phagocytosis was PKC-dependent and was associated with elevated microglial secretion of the chemoattractant chemokines, macrophage inflammatory protein-1alpha and macrophage chemoattractant protein-1. This suggested that microglial activation is negatively regulated by EP2 signaling through suppression of prophagocytic cytokine secretion. However, despite this enhancement of Abeta phagocytosis, lack of EP2 completely suppressed Abeta-activated microglia-mediated paracrine neurotoxicity. These data demonstrate that blockade of microglial EP2 is a highly desirable mechanism for AD therapy that can maximize neuroprotective actions while minimizing bystander damage to neurons.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amyloid beta-Peptides / metabolism*
  • Animals
  • Cell Count
  • Cells, Cultured
  • Chemokine CCL4
  • Chemotactic Factors / metabolism
  • Hippocampus / metabolism
  • Hippocampus / pathology
  • Macrophage Inflammatory Proteins / metabolism
  • Macrophages
  • Mice
  • Microglia / metabolism*
  • Neurons / metabolism
  • Neurons / pathology
  • Phagocytosis / physiology*
  • Protein Kinase C / metabolism
  • Receptors, Prostaglandin E / deficiency*

Substances

  • Amyloid beta-Peptides
  • Chemokine CCL4
  • Chemotactic Factors
  • Macrophage Inflammatory Proteins
  • Receptors, Prostaglandin E
  • Protein Kinase C