 |
The Journal of Neuroscience, November 23, 2005, 25(47):10960-10969; doi:10.1523/JNEUROSCI.1723-05.2005
Previous Article | Next Article 
Neurobiology of Disease
Intraneuronal -Amyloid Expression Downregulates the Akt Survival Pathway and Blunts the Stress Response
Jordi Magrané,1,2
Kenneth M. Rosen,1
Roy C. Smith,2
Kenneth Walsh,2
Gunnar K. Gouras,3 and
Henry W. Querfurth1
1Department of Neurology, Caritas Saint Elizabeth's Medical Center; Tufts University School of Medicine, Boston, Massachusetts 02135, 2Molecular Cardiology, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts 02118, and 3Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York, New York 10021
Early events in Alzheimer's disease (AD) pathogenesis implicate the accumulation of -amyloid (A ) peptide inside neurons in vulnerable brain regions. However, little is known about the consequences of intraneuronal A on signaling mechanisms. Here, we demonstrate, using an inducible viral vector system to drive intracellular expression of A 42 peptide in primary neuronal cultures, that this accumulation results in the inhibition of the Akt survival signaling pathway. Induction of intraneuronal A 42 expression leads to a sequential decrease in levels of phospho-Akt, increase in activation of glycogen synthase kinase-3 , and apoptosis. Downregulation of Akt also paralleled intracellular A accumulation in vivo in the Tg2576 AD mouse model. Overexpression of constitutively active Akt reversed the toxic effects of A through a mechanism involving the induction of heat shock proteins (Hsps). We used a small-interfering RNA approach to explore the possibility of a link between Akt activity and Hsp70 expression and concluded that neuroprotection by Akt could be mediated through downstream induction of Hsp70 expression. These results suggest that the early dysfunction associated with intraneuronal A accumulation in AD involve the associated impairments of Akt signaling and suppression of the stress response.
Key words: Alzheimer; intracellular; amyloid; Akt; Hsp; stress response
Received April 29, 2005;
revised September 20, 2005;
accepted October 9, 2005.
This article has been cited by other articles:

|
 |

|
 |
 
R. A. Fuentealba, Q. Liu, T. Kanekiyo, J. Zhang, and G. Bu
Low Density Lipoprotein Receptor-related Protein 1 Promotes Anti-apoptotic Signaling in Neurons by Activating Akt Survival Pathway
J. Biol. Chem.,
December 4, 2009;
284(49):
34045 - 34053.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
D. Tampellini, N. Rahman, E. F. Gallo, Z. Huang, M. Dumont, E. Capetillo-Zarate, T. Ma, R. Zheng, B. Lu, D. M. Nanus, et al.
Synaptic Activity Reduces Intraneuronal A{beta}, Promotes APP Transport to Synapses, and Protects against A{beta}-Related Synaptic Alterations
J. Neurosci.,
August 5, 2009;
29(31):
9704 - 9713.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
H.-K. Lee, P. Kumar, Q. Fu, K. M. Rosen, and H. W. Querfurth
The Insulin/Akt Signaling Pathway Is Targeted by Intracellular {beta}-Amyloid
Mol. Biol. Cell,
March 1, 2009;
20(5):
1533 - 1544.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
S. C. Biswas, Y. Shi, A. Sproul, and L. A. Greene
Pro-apoptotic Bim Induction in Response to Nerve Growth Factor Deprivation Requires Simultaneous Activation of Three Different Death Signaling Pathways
J. Biol. Chem.,
October 5, 2007;
282(40):
29368 - 29374.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
T. M. Malm, H. Iivonen, G. Goldsteins, V. Keksa-Goldsteine, T. Ahtoniemi, K. Kanninen, A. Salminen, S. Auriola, T. Van Groen, H. Tanila, et al.
Pyrrolidine Dithiocarbamate Activates Akt and Improves Spatial Learning in APP/PS1 Mice without Affecting {beta}-Amyloid Burden
J. Neurosci.,
April 4, 2007;
27(14):
3712 - 3721.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
P. Kumar, R. K. Ambasta, V. Veereshwarayya, K. M. Rosen, K. S. Kosik, H. Band, R. Mestril, C. Patterson, and H. W. Querfurth
CHIP and HSPs interact with {beta}-APP in a proteasome-dependent manner and influence A{beta} metabolism
Hum. Mol. Genet.,
April 1, 2007;
16(7):
848 - 864.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
C. G. Evans, S. Wisen, and J. E. Gestwicki
Heat Shock Proteins 70 and 90 Inhibit Early Stages of Amyloid beta-(1-42) Aggregation in Vitro
J. Biol. Chem.,
November 3, 2006;
281(44):
33182 - 33191.
[Abstract]
[Full Text]
[PDF]
|
 |
|
|

|