[ Back to EurekAlert! ] Public release date: 27-Feb-2007
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Contact: Professor Ole Isacson
isacson@hms.harvard.edu
617-855-3243
Public Library of Science

Proteasome activator enhances survival of Huntington's disease neuronal model cells

To function, each living cell needs both to build new and to degrade old or damaged proteins. To accomplish that, a number of intracellular systems work in concert to keep the cell healthy and from clogging up with damaged proteins. When proteins or peptides mutate, they can present major problems to the clearing up of the intracellular environment. In Huntington's disease (HD) the disease provoking mutation in the huntingtin gene eventually causes the cell to build up intranuclear and cellular inclusions of protein-aggregates, made up primarily of huntingtin. One cellular organelle with a central role of clearing such protein build up in the cell is the ubiquitin proteasome system (UPS).

In Huntington's disease (HD) brains and other tissues, UPS activity is inhibited and intraneuronal nuclear protein aggregates of mutant huntingtin in HD brains indicate dysfunction of the UPS. From these results, we hypothesized that enhancing UPS function would improve catalytic degradation of abnormal proteins in HD. We first genetically engineered proteasome activators involved in either non-ubiquitinated protein degradation pathways (PA28ƒ×) or subunits of PA700, the 26S proteasome ubiquitinated pathway (S5a) into transducible lentiviral vectors. To address the therapeutic hypothesis experimentally, we transduced UPS subunits into HD skin fibroblasts or HD mutant protein expressing striatum-derived neurons. We determined how this intervention altered cell survival after exposure to toxins known to simulate pathological mechanisms in HD.

The manuscript shows that cellular changes due to expression of huntingtin protein with longer CAG repeats can reduce the ubiquitin proteasome system (UPS) function in Huntington”¦s disease cells. Following compromise of the UPS, the overexpression of proteasome activator PA28 can specifically recover proteasome function and improve cell viability in both HD model and patient cells.

These remarkable results demonstrate for the first time that it is possible to intervene therapeutically in the proteolytic pathways and organelles that participate in the specific degradation of misfolded and abnormal proteins.

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The following press release refers to an upcoming article in PLoS ONE. The release has been provided by the article authors and/or their institutions. Any opinions expressed in this are the personal views of the contributors, and do not necessarily represent the views or policies of PLoS. PLoS expressly disclaims any and all warranties and liability in connection with the information found in the release and article and your use of such information.

CONTACT:

Adriana Bobinchock
McLean Hospital Public Affairs
Email: bobinca@mcleanpo.Mclean.org
Tel: +1 617-855-2110

Citation: Seo H, Sonntag K-C, Kim W, Cattaneo E, Isacson O (2007) Proteasome Activator Enhances Survival of Huntington”¦s Disease Neuronal Model Cells. PLoS ONE 2(2): e238. doi:10.1371/journal.pone.0000238

PLEASE ADD THE LINK TO THE PUBLISHED ARTICLE IN ONLINE VERSIONS OF YOUR REPORT: http://dx.doi.org/10.1371/journal.pone.0000238
PRESS ONLY PREVIEW: http://www.plos.org/press/pone-02-02-isacson.pdf



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