Clusterin (Apo J) Protects Against In Vitro Amyloid-β(1–40) Neurotoxicity

Clusterin is a secreted glycoprotein that is markedly induced in many disease states and after tissue injury. In the CNS, clusterin expression is elevated in neuropathological conditions such as Alzheimer's disease (AD), where it is found associated with amyloid-β (Aβ) plaques. Clusterin also coprecipitates with Aβ from CSF, suggesting a physiological interaction with Aβ. Given this interaction with Aβ, the goal of this study was to determine whether clusterin could modulate Aβ neurotoxicity. A mammalian recombinant source of human clusterin was obtained by stable transfection of hamster kidney fibroblasts with pADHC-9, a full-length human cDNA clone for clusterin. Recombinant clusterin obtained from this cell line, as well as a commercial source of native clusterin purified from serum, afforded dose-dependent neuroprotection against Aβ(1-40) when tested in primary rat mixed hipppocampal cultures. Clusterin afforded substoichiometric neuroprotection against several lots of Aβ(1- 40) but not against H 2 O 2 or kainic acid excitotoxicity. These results suggest that the elevated expression of clusterin found in AD brain may have effects on subsequent amyloid-β plaque pathology.