JPND - Intraneuronal transport-related pathways across neurodegenerative diseases

The overall goal of this proposal is to identify pathways/protein networks underlying the spreading of distinct aggregates of Abeta1-42, Tau, alpha-synuclein or HTTExon 1 involved in Alzheimer disease, Parkinson's disease, and Huntington disease, respectively. The spread of the lesions is a common feature of all these diseases, but strikingly starts and progresses in different brain sub-regions for each pathology. According to recent observations distinct aggregate conformers could be responsible for different clinical subtypes.

Here, we aim at revealing the specific mechanisms by which distinct fibrillary protein polymorphs of Abeta1-42, Tau, alpha-synuclein and HTTExon 1, are taken up and transported by neurons. We will use different types of mouse neurons maintained in primary culture to establish a structure-function relationship for distinct pathogenic protein assemblies and their conformers by analyzing their binding, uptake and cellular trafficking after extracellular application. By doing so we will address:
By doing so we will address:
1. How distinct pathogenic fibrillary protein polymorphs bind to neuronal cells and to which membrane components;
2. How exogenous pathogenic fibrillary proteins are taken up and transported;
3. How pathogenic fibrillary proteins traffic within cells by identifying;
4. The relationship between the traffic of pathogenic fibrillary proteins and neuronal activity;
5. The protein networks that account for distinct diseases;
6. How genetic risk factors affect the interactomes and transport mechanisms of distinct pathogenic fibrillary proteins polymorphs;
7. The identification of common pathways involved as novel therapeutic targets.

More specifically, we will
* quantify the binding of these distinct pathogenic fibrillary proteins polymorphs to the neuronal plasma membrane;
* identify their "receptors" or membrane protein partners;
* assess endocytosis;
* identify their cargoes within the cells;
* quantify intracellular transport and their export/release in the extracellular medium after anterograde or retrograde transport to identify common and divergent protein networks and characteristics that account for distinct diseases.

The different partners of this project have been selected for their expertise to cover these specific tasks.
* The LAC/ENS Paris-Saclay team will apply its recent intraneuronal transport assay, relying on fluorescent nanodiamond tracking.
* Neuro-PSI and CNCR teams have expertise in interaction proteomics to reveal proteins with functional similarities and specificities in the different trafficking steps.
* The consortium will also take advantage of novel mouse transgenic LOAD models, PD models and Halo-tagged-knockin models recently obtained and validated by the FP7-HEALTH AgedBrainSYSBIO consortium (coordinated by LAC/ENS Paris-Saclay) to identify common underlying mechanisms linked to intraneuronal transport.
* These readouts will be used to build quantitative models of aggregates trafficking and identify common pathways, using the expertise of the BI partner and of the MSSM as external partner.

The spread of the lesions is a common feature of Alzheimer disease, Parkinson's disease, and Huntington disease, but strikingly starts and progresses in different brain sub-regions for each pathology. According to recent observations distinct aggregate conformers could be responsible for different clinical subtypes.

Here, we aim at revealing the specific mechanisms by which distinct fibrillary protein polymorphs of Abeta1-42, Tau, alpha-synuclein and HTTExon 1, are taken up and transported by neurons. We will use different types of mouse neurons maintained in primary culture to establish a structure-function relationship for distinct pathogenic protein assemblies and their conformers by analyzing their binding, uptake and cellular trafficking after extracellular application. More specifically, we will quantify the binding of the fibrillary proteins polymorphs to the neuronal plasma membrane, identify their membrane protein partners, assess the role of endocytosis, identify their cargoes within the cells and quantify their intracellular transport and export/release in the extracellular medium, after anterograde or retrograde transport, to identify common and divergent protein networks and characteristics that account for distinct diseases.

By doing so we will address:
1. How distinct pathogenic fibrillary protein polymorphs bind to neuronal cells and to which membrane components;
2. How exogenous pathogenic fibrillary proteins are taken up and transported;
3. How pathogenic fibrillary proteins traffic within cells by identifying;
4. The relationship between the traffic of pathogenic fibrillary proteins and neuronal activity;
5. The protein networks that account for distinct diseases;
6. How genetic risk factors affect the interactomes and transport mechanisms of distinct pathogenic fibrillary proteins polymorphs;
7. The identification of common pathways involved as novel therapeutic targets.

Establishing protein interactions of Tau, Abeta, alpha-Syn or HTTExon1 fibrillary polymorphs with membrane- residing or intracellular transport proteins is a necessary step to elucidate the mechanism of toxicity and spreading of these proteins in neurodegenerative disease. Our novel approaches including (i) the preparation of fibrillary protein strains, (ii) the quantification of their intraneuronal transport, (iii) the analysis of their interactomes by mass spectrometry and systems biology will drastically improve the chance to unravel new mechanisms, and will provide new targets for the development of specific treatment strategies. Considering the potential use of our results to design treatments for patients, we will put the emphasis on the quick dissemination of our results to the scientific community.

As for AgedBrainSYSBIO consortium coordinated by Partner 1, all quantitative data will be included in datasets to be published in open access journals (e.g. Scientific Data, Nature-Springer) and deposited in the EMBL-EBI database Intact. Furthermore, experimental data will be published in BioRxiv before submission to peer-review journals, in order to provide a rapid data access for the scientific community and to avoid delays induced by slow reviewing. Dissemination of our result to the public will be also be done via a dedicated website.