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ANR funded project

Emergence (Emergence)
Edition 2012


HuntToTreat


New therapeutic strategy for Huntington’s disease

HuntToTreat
New therapeutic strategy for Huntington’s disease

Finding drugs and treatments that will alleviate the disease and/or its symptoms.
- Development of tools for P42 delivery
- Find appropriate ways of delivery
- Test in vivo in Huntington's disease mouse model

Test of activity of P42-TAT
- test in HeLa cells in culture
- test in vivo in R6/2 mice

Results

-The fusion peptide P42-TAT is able to enter HeLa cells when provided in the culture medium. Addition of TAT does not modify the protective properties of P42. There is a clear dose-response effect of the fusion peptide.
- Different methods of administration of P42-TAT have been tested in mice through brain sections analysis by MALDI. Use of peptide inserted in nanoparticles (Aonys technology, Medesis-pharma) and orally administrated allows a clear targeting of the peptide to the brain.
- R6/2 HD mice model have been treated by oral spray with P42-TAT nanoparticles, which drives a rescue of R6/2 behaviors (such as rotarod defects, or foot clasping phenotype), and a rescue of the loss of weight of these mice.

Outlook

1- A more careful analysis of P42-TAT derivatives identified in the brain after ICV or after oral administration in nanoparticles.
2- An improvement of the peptide though its shortening to identify the active part. This will allow in particular to use a more concentrated drug.
3- Comparison of P42 and P42-TAT in Drosophila to test their relative diffusion and ability to impact on polyQ-hHtt induced phenotypes.
4- Study in R6/2 model will be pursued by following biomarkers on brain sections, to measure aggregation, astrocytes, size of the ventricles to measure the brain volume.
5-Test of bi-therapies using P42-TAT and lithium.

Scientific outputs and patents

- Arribat Y, Bonneaud, N, Talmat-Amar Y., Layalle, S., Parmentier ML, Maschat, F. «A Huntingtin peptide inhibits polyQ-Huntingtin associated defects”. Article in revision

Partners

FIST France Innovation Scientifique et Transfert

IGF Institut de Génomique Fonctionnelle - Eq Neurobiologie normale et pathologique chez la Drosophile

ANR grant: 250 175 euros
Beginning and duration: décembre 2012 - 24 mois

Submission abstract

Huntington’s disease (HD) is an inherited neurodegenerative disorder due to an abnormal expansion of a polyQ domain in the N-terminus of the human Huntingtin (hHtt) protein. When polyQ exceeds 35, polyQ-hHtt forms aggregates, and drives cell toxicity, leading to striatum neurodegeneration.
Although a number of molecular dysfunctions have been elucidated and help to explain the striatal neurodegeneration observed in HD, the exact mechanism whereby mutation in Huntingtin causes this neurodegeneration is still unclear. Several studies, including ours, indicate an influence of normal hHtt on the disease. Using a Drosophila model of HD, expressing a polyQ-hHtt, we could rescue polyQ-hHtt induced toxicity with the 548aa N-terminus part of hHtt or with the 620aa N-terminus part of Drosophila Ht (dHtt). These results suggest that HD must be considered as a dominant negative disease since the presence of expanded polyQ not only makes the mutated protein itself toxic, but also alters the normal functions of Htt. They also show that human and Drosophila Htt share biological properties, making Drosophila a privileged organism to study HD.
Therefore in a quest to find cures for HD, our project consists in developing a peptide-based strategy to protect cells against polyQ-hHtt toxicity. Based on our results indicating the protective role of normal Htt N-terminus, we recently identified a 23aa peptide (pep42) lying within the 548aa N-terminal part of the normal hHtt that is able to inhibit different phenotypes induced by the expression of the polyQ-hHtt in HeLa cells and in flies. Molecularly we identified how pep42 interferes with the first step of aggregation of the polyQ-hHtt (namely the nucleation step) through an interaction with the first N-terminal 17 aa (N17 region). At therapeutic ends, we now plan to fuse pep42 to a protein transduction domain such as (TAT-HIV) to be able to deliver the peptide into brain cells to treat the disease. The protective effect of the pep42-TAT fusion peptide will be therefore tested first in HeLa cells, then in entire organisms, notably in Drosophila, and in mice. The project benefits from the methodical characterization of the different neuronal defects that are induced by polyQ-hHtt in Drosophila that we have completed in our laboratory. This knowledge will be used to study the protective effect of pep42-TAT in vivo, comparative to pep42 alone, with the aim to also test their relative diffusion in an entire organism and their targeting in neurons. Finally tests will be performed in a mouse model of HD, where various delivery routes of pep42-TAT will be compared (intraventriculary or intravenous injections). Brain sections will be analyzed to test the efficiency of pep42-TAT delivery as well as its ability to rescue the polyQ-hHtt aggregates. Protective effects of the peptide will be also analyzed on mutated R6(2) mice associated behavioural defects. Once the proof of concept for the protective effect by pep42-TAT will be shown, an important issue will be to find more comfortable delivery process for the animal than injections, such as oral administration.

 

ANR Programme: Emergence (Emergence) 2012

Project ID: ANR-12-EMMA-0013

Project coordinator:
Madame Florence MASCHAT (Institut de Génomique Fonctionnelle - Eq Neurobiologie normale et pathologique chez la Drosophile )
Florence.Maschat@nulligf.cnrs.fr

 

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The project coordinator is the author of this abstract and is therefore responsible for the content of the summary. The ANR disclaims all responsibility in connection with its content.