Prion protein attenuates excitotoxicity by inhibiting NMDA receptors.
It is well established that misfolded forms of cellular prion protein (PrP [PrPC]) are crucial in the genesis and progression of transmissible spongiform encephalitis, whereas the function of native PrPC remains incompletely understood. To determine the physiological role of PrPC, we examine the neurophysiological properties of hippocampal neurons isolated from PrP-null mice. We show that PrP-null mouse neurons exhibit enhanced and drastically prolonged N-methyl-D-aspartate (NMDA)-evoked currents as a result of a functional upregulation of NMDA receptors (NMDARs) containing NR2D subunits. These effects are phenocopied by RNA interference and are rescued upon the overexpression of exogenous PrPC. The enhanced NMDAR activity results in an increase in neuronal excitability as well as enhanced glutamate excitotoxicity both in vitro and in vivo. Thus, native PrPC mediates an important neuroprotective role by virtue of its ability to inhibit NR2D subunits.
Khosravani
Houman
H
Department of Physiology and Biophysics, Hotchkiss Brain Institute, University of Calgary, Calgary T2N4N1, Canada.
Zhang
Yunfeng
Y
Tsutsui
Shigeki
S
Hameed
Shahid
S
Altier
Christophe
C
Hamid
Jawed
J
Chen
Lina
L
Villemaire
Michelle
M
Ali
Zenobia
Z
Jirik
Frank R
FR
Zamponi
Gerald W
GW