Microglia lacking E prostanoid receptor subtype 2 have enhanced Aβ phagocytosis yet lack Aβ-activated neurotoxicity

FS Shie, RM Breyer, TJ Montine - The American journal of pathology, 2005 - Elsevier
The American journal of pathology, 2005Elsevier
Experimental therapies for Alzheimer's disease (AD) are focused on enhanced clearance of
neurotoxic Aβ peptides from brain. Microglia can be neuroprotective by phagocytosing Aβ;
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 Aβ peptides from AD brain sections
and enhanced microglial Aβ phagocytosis in cell culture. The enhanced phagocytosis was …
Experimental therapies for Alzheimer's disease (AD) are focused on enhanced clearance of neurotoxic Aβ peptides from brain. Microglia can be neuroprotective by phagocytosing Aβ; 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 Aβ peptides from AD brain sections and enhanced microglial Aβ phagocytosis in cell culture. The enhanced phagocytosis was PKC-dependent and was associated with elevated microglial secretion of the chemoattractant chemokines, macrophage inflammatory protein-1α 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 Aβ phagocytosis, lack of EP2 completely suppressed Aβ-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.
Elsevier