GENERATION OF CELL AND ANIMAL MODELS TO MONITOR THE ROLE OF THE UNFOLDED PROTEIN RESPONSE IN DEVELOPMENT AND IN GENETIC DISEASES

To design an effective and safe therapy, we must precisely determine the molecular mechanisms underlying the disease. We must also be able to predict the consequences of our actions, and evaluate whether the benefits exceed the risks. Many genetic diseases are due to a loss of function, caused by the absence of a given molecular component. In these cases, it is easy –at least at first sight- to reconstruct the pathogenesis of the disease, and to design strategies to provide the missing element. In contrast, many dominant diseases are due to a gain of function, often caused by the accumulation of a toxic protein. However, for largely unknown reasons, the toxicity varies amongst individuals and, within the same individual, amongst different tissues or even cell types. For instance, in Hungtington Disease only certain neurons suffer from the synthesis of a mutated protein, which is instead well tolerated by other cells that also produce it as abundantly. Moreover, certain diseases arise owing to the excessive production of an otherwise normal protein. Therefore, to design and/or optimise gene therapy protocols, we need to learn more about the quality control mechanisms that cells exert on their protein products. Our project aims at characterising the molecular mechanisms by which cells respond to the synthesis of aberrant proteins or proteins in excess. These generally consist in the increased production of a particular class of protective proteins, the molecular chaperones, and in the attempt to degrade the mutant proteins. In particular, we propose to construct a reporter that would allow us to readily monitor the efficiency of these responses in living cells. We hope that this reagent will prove useful not only to unravel the basic cellular defense mechanisms, but also to design protocols to manipulate protective responses to aberrant or mutated proteins in human cells.