Stabilization of 14-3-3 protein-protein interactions with Fusicoccin-A decreases alpha-synuclein dependent cell-autonomous death in neuronal and mouse models
Rodrigo Vinueza-Gavilanes 1 , Jorge Juan Bravo-González 2 , Leyre Basurco 3 , Chiara Boncristiani 4 , Joaquín Fernández-Irigoyen 5 , Enrique Santamaría 6 , Irene Marcilla 7 , Alberto Pérez-Mediavilla 8 , María Rosario Luquin 9 , Africa Vales 10 , Gloria González-Aseguinolaza 11 , María Soledad Aymerich 12 , Tomás Aragón 13 , Montserrat Arrasate 14
Synucleinopathies are a group of neurodegenerative diseases without effective treatment characterized by the abnormal aggregation of alpha-synuclein (aSyn) protein. Changes in levels or in the amino acid sequence of aSyn (by duplication/triplication of the aSyn gene or point mutations in the encoding region) cause familial cases of synucleinopathies.
However, the specific molecular mechanisms of aSyn-dependent toxicity remain unclear. Increased aSyn protein levels or pathological mutations may favor abnormal protein-protein interactions (PPIs) that could either promote neuronal death or belong to a coping response program against neurotoxicity.
Therefore, the identification and modulation of aSyn-dependent PPIs can provide new therapeutic targets for these diseases. To identify aSyn-dependent PPIs we performed a proximity biotinylation assay based on the promiscuous biotinylase BioID2. When expressed as a fusion protein, BioID2 biotinylates by proximity stable and transient interacting partners, allowing their identification by streptavidin affinity purification and mass spectrometry.
The aSyn interactome was analyzed using BioID2-tagged wild-type (WT) and pathological mutant E46K aSyn versions in HEK293 cells. We found the 14-3-3 epsilon isoform as a common protein interactor for WT and E46K aSyn. 14-3-3 epsilon correlates with aSyn protein levels in brain regions of a transgenic mouse model overexpressing WT human aSyn.
Using a neuronal model in which aSyn cell-autonomous toxicity is quantitatively scored by longitudinal survival analysis, we found that stabilization of 14-3-3 protein-proteins interactions with Fusicoccin-A (FC-A) decreases aSyn-dependent toxicity. Furthermore, FC-A treatment protects dopaminergic neuronal somas in the substantia nigra of a Parkinson's disease mouse model.
Based on these results, we propose that the stabilization of 14-3-3 epsilon interaction with aSyn might reduce aSyn toxicity, and highlight FC-A as a potential therapeutic compound for synucleinopathies.
CITATION Neurobiol Dis. 2023 May 26;106166. doi: 10.1016/j.nbd.2023.106166