One of the most interesting discoveries originated from my research work that is directly related to this proposal, was the identification of one mechanism of -syn propagation using quantitative fluorescence microscopy of co-cultured neuronal cells. In that work, I demonstrated that -syn fibrils efficiently transfer from one cell to the other through tunneling nanotubes (TNTs) inside lysosomal vesicles. Furthermore, I also showed for the first time the formation of TNTs between neuronal cells and primary neurons and determined and quantified that the propagation of -syn fibrils between primary neurons is mainly dependent on cell-to-cell contact, which is of vital importance for understanding how PD progress. Another important contribution of my work to the field of synucleinopathies is the establishment of several in vitro and ex vivo models that allowed the quantification of a selective intercellular communication between astrocytes and neurons. In that work, I demonstrated the role of astrocytes in the intercellular transfer and fate of α-syn fibrils. Besides, I showed that α-syn fibrils are transferred in a non-cell autonomous manner, but the transfer efficiency changes depending on the cell types; α-syn is efficiently transferred from astrocytes to astrocytes and from neurons to astrocytes, but less efficiently from astrocytes to neurons. However, differently from neurons, which are unable to degrade the fibrils, astrocytes efficiently degrade fibrillar α-syn, suggesting an active role for these cells in clearing α-syn deposits. In addition, I successfully developed a novel co-culture system where primary mouse astrocytes were cultured on top of organotypic hippocampal slices, where they integrated and interacted with the cells of the slice. This new model has proven to be important for studying α-syn trafficking in the disease state, given that it represents the first model to look at cellular transfer of α-syn in the presence of all glial cell types.
The results derived from this project have been disseminated in the following peer-reviewed articles, meetings and conferences:
Loria F, et al, 2017, DOI: 10.1007/s00401-017-1746-2
Abounit S et al, 2016, DOI: 10.15252/embj.201593411
In vitro and ex vivo assessment of the role of astrocytes in the spreading of alpha-synuclein aggregates. The Society of Neuroscience Annual Meeting. Washington DC, USA. 2017.
In vitro and ex vivo assessment of α-synuclein spreading in neurons and astrocytes. Seminar, Institut Pasteur, Paris, France. 2017.
Identification of the cellular players involved in the spreading of α-synuclein. The 13th International Conference on Alzheimer’s & Parkinson’s Diseases. Vienna, Austria. 2017.
Identification of cellular players involved in the spreading of α-synuclein. BCI Annual Retreat. Institut Pasteur, Paris, France. 2016.
In vitro and ex vivo assessment and quantification of α-synuclein intercellular spreading. Institut Pasteur, Quantitative Biology Meeting. Paris, France. 2016.
Mechanisms of alpha-synuclein spreading in neurons, role of tunneling nanotubes. EMBO Workshop on Membrane fusion in health and disease. Paris, France. 2016.
Mechanisms of α-synuclein intercellular spreading involved in Parkinson’s disease progression. EMBO Workshop on Membrane fusion in health and disease. Paris, France. 2016. Poster.
Mechanisms of α-synuclein intercellular spreading involved in Parkinson’s disease progression. StaPa-ADIC Joint Retreat Normandie, France. 2016.