TY - JOUR

T1 - In vivo uptake of β-amyloid by non-plaque associated microglia

AU - Hawkes, Cheryl A.

AU - Deng, LeHua H.

AU - Fenili, Daniela

AU - Nitz, Mark

AU - McLaurin, JoAnne A.

PY - 2012/10/26

Y1 - 2012/10/26

N2 - The role of microglia in β-amyloid (Aβ) deposition or clearance in the Alzheimer's disease (AD) brain remains unclear. Previous in vivo studies have focused primarily on the association of microglia with Aβ-positive parenchymal plaques, but have given little consideration to the possible interaction between Aβ and non-plaque associated microglia. Further, it is not known if microglia play a direct role in mediating Aβ uptake following anti-aggregant treatment. We report here the identification of Aβ-positive processes throughout the cortex and hippocampus of TgCRND8 mice expressing the human Swedish (KM670/671NL) and Indiana (V717F) amyloid precursor protein mutations, which localized to ionized calcium binding protein-1-positive resident microglia that were not associated with extracellular plaques. Oral administration of 1-deoxy-1-fluoro-scyllo-inositol, a scyllo-inositol analogue, to TgCRND8 mice improved spatial memory impairments and suppressed amyloid pathology in a dose-dependent manner. Further, treatment with 1-deoxy-1- fluoro-scyllo-inositol significantly increased hippocampal intra-microglial Aβ levels without stimulating microglial proliferation or peripheral macrophage recruitment. These results reveal a novel, beneficial role for non-plaque associated microglia in the regulation of cerebral Aβ levels in a mouse model of AD.

AB - The role of microglia in β-amyloid (Aβ) deposition or clearance in the Alzheimer's disease (AD) brain remains unclear. Previous in vivo studies have focused primarily on the association of microglia with Aβ-positive parenchymal plaques, but have given little consideration to the possible interaction between Aβ and non-plaque associated microglia. Further, it is not known if microglia play a direct role in mediating Aβ uptake following anti-aggregant treatment. We report here the identification of Aβ-positive processes throughout the cortex and hippocampus of TgCRND8 mice expressing the human Swedish (KM670/671NL) and Indiana (V717F) amyloid precursor protein mutations, which localized to ionized calcium binding protein-1-positive resident microglia that were not associated with extracellular plaques. Oral administration of 1-deoxy-1-fluoro-scyllo-inositol, a scyllo-inositol analogue, to TgCRND8 mice improved spatial memory impairments and suppressed amyloid pathology in a dose-dependent manner. Further, treatment with 1-deoxy-1- fluoro-scyllo-inositol significantly increased hippocampal intra-microglial Aβ levels without stimulating microglial proliferation or peripheral macrophage recruitment. These results reveal a novel, beneficial role for non-plaque associated microglia in the regulation of cerebral Aβ levels in a mouse model of AD.

KW - Alzheimer's disease

KW - Anti-aggregant

KW - Transgenic mouse model

U2 - 10.2174/156720512803251084

DO - 10.2174/156720512803251084

M3 - Journal article

C2 - 22272621

AN - SCOPUS:84864318278

VL - 9

SP - 890

EP - 901

JO - Current Alzheimer Research

JF - Current Alzheimer Research

SN - 1567-2050

IS - 8

ER -