We have hypothesized that Aβ oligomer binding to cellular prion protein (PrPC) plays a central role in the pathogenesis of Alzheimer’s disease (AD) (Gimbel et al., 2010; Lauren et al., 2009; Um et al., 2012). Two recent papers, this one together with Fluharty et al., 2013, provide further evidence for a key role of PrPC in Aβ-mediated toxicity.
Here, Hooper and colleagues show that specific assemblies of Aβ preferentially bind to PrPC, with downstream activation of the Src family kinase Fyn. We recently defined a signaling cascade by which Aβ activates Fyn and the NR2B subunit of the NMDA receptor in a PrPC-dependent fashion (Um et al., 2012). In addition, similar findings were recently reported by Larson et al. (Larson et al., 2012), providing strong converging evidence for a pathologic Aβ-PrPC-Fyn signaling cascade in AD models. PrPC does not cross the plasma membrane, and the putative transmembrane partners mediating the effects of the Aβ-PrPC complex on Fyn have not been identified. Rushworth et al. suggest that LRP1 links Aβ-PrPC to certain signaling events, and it will be important to explore these interesting findings and expand the search for transmembrane co-receptors.
Harris and colleagues (Fluharty et al., 2013) confirm that the critical PrPC binding sites for Aβ oligomers are within the N-terminal region of PrPC. They further show that addition of the soluble N-terminal fragment sequesters soluble Aβ, and prevents toxicity mediated by Aβ oligomers both in vitro and in vivo. These findings are similar to the long-term potentiation findings reported by Aguzzi and colleagues (Calella et al., 2010) indicating that the soluble N-terminal fragment of PrPC may serve as an anti-Aβ therapeutic.
Defining the pathologic Aβ signaling cascade remains a major objective in AD research. Following our report (Um et al., 2012), the recent studies confirm a critical pathway by which Aβ activates Fyn kinase in a PrPC-dependent fashion (Larson et al., 2012; Rushworth et al., 2013). Moving forward, it will be important to delineate additional components of the Aβ-PrPC signaling cascade, and, critically, to evaluate this pathway in human disease. Selective targeting of PrPC itself, or the Aβ-PrPC signaling pathway, represent novel and promising therapeutic interventions for AD.
References:
Calella AM, Farinelli M, Nuvolone M, Mirante O, Moos R, Falsig J, Mansuy IM, Aguzzi A.
Prion protein and Abeta-related synaptic toxicity impairment.
EMBO Mol Med. 2010 Aug;2(8):306-14.
PubMed.
Fluharty BR, Biasini E, Stravalaci M, Sclip A, Diomede L, Balducci C, La Vitola P, Messa M, Colombo L, Forloni G, Borsello T, Gobbi M, Harris DA.
An N-terminal fragment of the prion protein binds to amyloid-β oligomers and inhibits their neurotoxicity in vivo.
J Biol Chem. 2013 Mar 15;288(11):7857-66.
PubMed.
Gimbel DA, Nygaard HB, Coffey EE, Gunther EC, Laurén J, Gimbel ZA, Strittmatter SM.
Memory impairment in transgenic Alzheimer mice requires cellular prion protein.
J Neurosci. 2010 May 5;30(18):6367-74.
PubMed.
Larson M, Sherman MA, Amar F, Nuvolone M, Schneider JA, Bennett DA, Aguzzi A, Lesné SE.
The complex PrP(c)-Fyn couples human oligomeric Aβ with pathological tau changes in Alzheimer's disease.
J Neurosci. 2012 Nov 21;32(47):16857-71a.
PubMed.
Laurén J, Gimbel DA, Nygaard HB, Gilbert JW, Strittmatter SM.
Cellular prion protein mediates impairment of synaptic plasticity by amyloid-beta oligomers.
Nature. 2009 Feb 26;457(7233):1128-32.
PubMed.
Rushworth JV, Griffiths HH, Watt NT, Hooper NM.
Prion Protein-mediated Toxicity of Amyloid-β Oligomers Requires Lipid Rafts and the Transmembrane LRP1.
J Biol Chem. 2013 Mar 29;288(13):8935-51.
PubMed.
Um JW, Nygaard HB, Heiss JK, Kostylev MA, Stagi M, Vortmeyer A, Wisniewski T, Gunther EC, Strittmatter SM.
Alzheimer amyloid-β oligomer bound to postsynaptic prion protein activates Fyn to impair neurons.
Nat Neurosci. 2012 Sep;15(9):1227-35. Epub 2012 Jul 22
PubMed.
Comments
Yale University School of Medicine
We have hypothesized that Aβ oligomer binding to cellular prion protein (PrPC) plays a central role in the pathogenesis of Alzheimer’s disease (AD) (Gimbel et al., 2010; Lauren et al., 2009; Um et al., 2012). Two recent papers, this one together with Fluharty et al., 2013, provide further evidence for a key role of PrPC in Aβ-mediated toxicity.
Here, Hooper and colleagues show that specific assemblies of Aβ preferentially bind to PrPC, with downstream activation of the Src family kinase Fyn. We recently defined a signaling cascade by which Aβ activates Fyn and the NR2B subunit of the NMDA receptor in a PrPC-dependent fashion (Um et al., 2012). In addition, similar findings were recently reported by Larson et al. (Larson et al., 2012), providing strong converging evidence for a pathologic Aβ-PrPC-Fyn signaling cascade in AD models. PrPC does not cross the plasma membrane, and the putative transmembrane partners mediating the effects of the Aβ-PrPC complex on Fyn have not been identified. Rushworth et al. suggest that LRP1 links Aβ-PrPC to certain signaling events, and it will be important to explore these interesting findings and expand the search for transmembrane co-receptors.
Harris and colleagues (Fluharty et al., 2013) confirm that the critical PrPC binding sites for Aβ oligomers are within the N-terminal region of PrPC. They further show that addition of the soluble N-terminal fragment sequesters soluble Aβ, and prevents toxicity mediated by Aβ oligomers both in vitro and in vivo. These findings are similar to the long-term potentiation findings reported by Aguzzi and colleagues (Calella et al., 2010) indicating that the soluble N-terminal fragment of PrPC may serve as an anti-Aβ therapeutic.
Defining the pathologic Aβ signaling cascade remains a major objective in AD research. Following our report (Um et al., 2012), the recent studies confirm a critical pathway by which Aβ activates Fyn kinase in a PrPC-dependent fashion (Larson et al., 2012; Rushworth et al., 2013). Moving forward, it will be important to delineate additional components of the Aβ-PrPC signaling cascade, and, critically, to evaluate this pathway in human disease. Selective targeting of PrPC itself, or the Aβ-PrPC signaling pathway, represent novel and promising therapeutic interventions for AD.
References:
Calella AM, Farinelli M, Nuvolone M, Mirante O, Moos R, Falsig J, Mansuy IM, Aguzzi A. Prion protein and Abeta-related synaptic toxicity impairment. EMBO Mol Med. 2010 Aug;2(8):306-14. PubMed.
Fluharty BR, Biasini E, Stravalaci M, Sclip A, Diomede L, Balducci C, La Vitola P, Messa M, Colombo L, Forloni G, Borsello T, Gobbi M, Harris DA. An N-terminal fragment of the prion protein binds to amyloid-β oligomers and inhibits their neurotoxicity in vivo. J Biol Chem. 2013 Mar 15;288(11):7857-66. PubMed.
Gimbel DA, Nygaard HB, Coffey EE, Gunther EC, Laurén J, Gimbel ZA, Strittmatter SM. Memory impairment in transgenic Alzheimer mice requires cellular prion protein. J Neurosci. 2010 May 5;30(18):6367-74. PubMed.
Larson M, Sherman MA, Amar F, Nuvolone M, Schneider JA, Bennett DA, Aguzzi A, Lesné SE. The complex PrP(c)-Fyn couples human oligomeric Aβ with pathological tau changes in Alzheimer's disease. J Neurosci. 2012 Nov 21;32(47):16857-71a. PubMed.
Laurén J, Gimbel DA, Nygaard HB, Gilbert JW, Strittmatter SM. Cellular prion protein mediates impairment of synaptic plasticity by amyloid-beta oligomers. Nature. 2009 Feb 26;457(7233):1128-32. PubMed.
Rushworth JV, Griffiths HH, Watt NT, Hooper NM. Prion Protein-mediated Toxicity of Amyloid-β Oligomers Requires Lipid Rafts and the Transmembrane LRP1. J Biol Chem. 2013 Mar 29;288(13):8935-51. PubMed.
Um JW, Nygaard HB, Heiss JK, Kostylev MA, Stagi M, Vortmeyer A, Wisniewski T, Gunther EC, Strittmatter SM. Alzheimer amyloid-β oligomer bound to postsynaptic prion protein activates Fyn to impair neurons. Nat Neurosci. 2012 Sep;15(9):1227-35. Epub 2012 Jul 22 PubMed.
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