Maura Samarani (France)
Institut Pasteur
Cell Biology and Infection
Dr. Maura Samarani received her Ph.D. in Biochemical Sciences from the University of Milan (Italy) where she studied the role of lysosomal dysfunction and plasma membrane sphingolipids in the onset of cell damage. Dr. Samarani is currently a postdoc in the Unit of Membrane Traffic and Pathogenesis headed by Prof. Chiara Zurzolo at the Institut Pasteur (Paris, France). In the Zurzolo group, Dr. Samarani aims to understand how lysosomes transferred between cells through Tunneling nanotubes (TNTs) contribute to the spreading of α-synuclein and to the neuronal damage in Parkinson’s disease. She is also interested in understanding the involvement of TNTs in the etiopathogenesis of Lysosomal Storage Disorders. Since she was a Ph.D. student, Dr. Samarani is involved in different outreach activities for adults and children (e.g., European Researchers’ Night, workshops in primary schools, collaboration with the association Native Scientist for pupils speaking Italian in Paris).

Presenter of 1 Presentation

 Conference Calendar

LYSOSOMES ARE A HUB FOR SEEDING NEW ALPHA-SYNUCLEIN AGGREGATES AND PROMOTE THEIR INTERCELLULAR SPREADING THROUGH TUNNELING NANOTUBES

Session Name
0750 - ALPHA-SYNUCLEIN AND DISEASE MECHANISMS (ID 38)
Session Type
SYMPOSIUM
Date
Thu, 17.03.2022
Session Time
02:45 PM - 04:45 PM
Room
ONSITE: 114
Lecture Time
03:15 PM - 03:30 PM
Presenter

Abstract

Aims

The accumulation of alpha-synuclein aggregates in specific brain regions is a hallmark of synucleinopathies including Parkinson’s disease. Alpha-synuclein aggregates propagate in a “prion-like” manner and can be transferred inside lysosomes to recipient cells through tunneling nanotubes (TNTs), which are actin-based, thin cellular protrusions connecting remote cells. However, how lysosomes contribute to the spreading of alpha-synuclein aggregates is unknown.

Methods

We performed super-resolution and electron microscopy, immunocytochemistry, and gene overexpression/downregulation experiments to study the role of lysosomes in the propagation of alpha-synuclein pathology in neuronal cells.

Results

We found that alpha-synuclein fibrils affect the morphology of lysosomes and impair their function. In addition, we demonstrated that alpha-synuclein fibrils induce peripheral redistribution of lysosomes, likely mediated by TFEB, increasing the efficiency of fibrils’ transfer to neighboring cells. We also showed that lysosomal membrane permeabilization allows the seeding of soluble alpha-synuclein in cells that have taken up alpha-synuclein fibrils from the culture medium and, more importantly, in healthy cells in co-culture following the lysosome-mediated transfer of the fibrils. Moreover, we demonstrated that seeding occurs mainly at lysosomes in both donor and acceptor cells after the uptake of alpha-synuclein fibrils from the medium and following their transfer. Finally, by using a heterotypic co-culture system, we showed that donor cells bearing alpha-synuclein fibrils transfer damaged lysosomes to acceptor cells, while also receiving healthy lysosomes from them.

Conclusions

Collectively, our findings indicate that lysosomes damaged by alpha-synuclein fibrils become a hub for seeding new aggregates and function as a Trojan horse facilitating the dissemination of misfolded aggregates through TNTs.

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