Transcellular propagation of fibrillar α-synuclein from enteroendocrine to neuronal cells requires cell-to-cell contact and is Rab35-dependent
Abstract
Parkinson's disease (PD) is a neurodegenerative condition featured by motor dysfunction, death of midbrain dopaminergic neurons and accumulation of α-synuclein (αSyn) aggregates. Growing evidence suggests that PD diagnosis happens late in the disease progression and that the pathology may originate much earlier in the enteric nervous system (ENS) before advancing to the brain, via autonomic fibers. It was recently described that a specific cell type from the gut epithelium named enteroendocrine cells (EECs) possess many neuron-like properties including αSyn expression. By facing the gut lumen and being directly connected with αSyn-containing enteric neurons in a synaptic manner, EECs form a neural circuit between the gastrointestinal tract and the ENS, thereby being a possible key player in the outcome of PD in the gut. We have characterized the progression and the cellular mechanisms involved in αSyn pre-formed fibrils (PFFs) transfer from EECs to neuronal cells. We show that brain organoids efficiently internalize αSyn PFF seeds which triggers the formation of larger intracellular inclusions. In addition, in the enteroendocrine cell line STC-1 and in the neuronal cell line SH-SY5Y, αSyn PFFs induced intracellular calcium (Ca²⁺) oscillations on an extracellular Ca²⁺ source-dependent manner and triggered αSyn fibrils internalization by endocytosis. We characterized the spread of αSyn PFFs from enteroendocrine to neuronal cells and showed that this process is dependent on physical cell-to-cell contact and on Rab35 GTPase. Lastly, inhibition of Rab35 increases the clearance of αSyn fibrils by redirecting them to the lysosomal compartment. Therefore, our results reveal mechanisms that contribute to the understanding of how seeded αSyn fibrils promote the progression of αSyn pathology from EECs to neuronal cells shifting the focus of PD etiology to the ENS.
Additional Information
© The Author(s) 2022. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. Received 02 December 2021. Accepted 02 March 2022. Published 09 March 2022. We acknowledge the Spectroscopy and Calorimetry facility of the Brazilian Biosciences National Laboratory (LNBio), CNPEM, Campinas, Brazil, for the support in biophysical assays. The authors would like to acknowledge support of INFABIC, Unicamp, Brazil. This work was supported by the Coordination of Superior Level Staff Improvement (CAPES), the Brazilian National Council for Scientific and Technological Development (CNPq) and grants from São Paulo Research Foundation (FAPESP to M.C.F, 2018/20014-0, 2019/24511-0). Method cartoons were created with BioRender.com. This work was supported by CAPES, CNPq (465699/2014-6) and FAPESP (2018/20014-0, 2019/24511-0, 2014/50938-8). INFABIC is co-funded by FAPESP (2014/50938-8) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) (465699/2014-6). Data and code availability. All data are available within the article or its supplementary materials. Any additional information is available from the Corresponding author on request. Materials availability. All developed expression plasmids produced in this study can be made available upon request to the Corresponding Author. Contributions. P.V.R., C.C.C.T. and M.C.F. conceived, initiated, and coordinated the project. P.V.R., J.V.P.G., B.P.B., D.P.A.N., K.T., S.P and S.G.R, designed and performed the experimental work. C.C.C.T. and M.C.F. supplied reagents. P.V.R., J.V.P.G., C.C.C.T., H.F.C. and M.C.F. provided essential discussion and advice. H.F.C and M.C.F. performed the main fundraising. P.V.R. and M.C.F. wrote the manuscript. All authors discussed the experiments and results, read, and approved the manuscript. The authors declare no competing interests.Attached Files
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Additional details
- Eprint ID
- 113810
- Resolver ID
- CaltechAUTHORS:20220309-982124000
- Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
- 465699/2014-6
- Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
- 2018/20014-0
- Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
- 2019/24511-0
- Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
- 2014/50938-8
- Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
- Created
-
2022-03-09Created from EPrint's datestamp field
- Updated
-
2022-03-09Created from EPrint's last_modified field