Sin-PARK II

Artículos científicos

• Basurco L, Abellanas MA, Ayerra L, Conde E, Vinueza-Gavilanes R, Luquin E, Vales A, Vilas A, Martin-Uriz PS, Tamayo I, Alonso MM, Hernaez M, Gonzalez-Aseguinolaza G, Clavero P, Mengual E, Arrasate M, Hervás-Stubbs S, Aymerich MS (2023): “Microglia and astrocyte activation is region-dependent in the α-synuclein mouse model of Parkinson’s disease”. Glia. 2023 71(3):571-587. Artículo resaltado en Nat Rev Neurology (2023). (https://onlinelibrary.wiley.com/doi/full/10.1002/glia.24295)
• Rodrigo Vinueza-Gavilanes, Jorge Juan Bravo-González, Leyre Basurco, Chiara Boncristiani, Joaquín Fernández-Irigoyen, Enrique Santamaría, Irene Marcilla, Alberto Pérez-Mediavilla, María Rosario Luquin, Africa Vales, Gloria González-Aseguinolaza, María Soledad Aymerich, Tomás Aragón, Montserrat Arrasate (2023): “Stabilization of 14-3-3 protein-protein interactions with Fusicoccin-A decreases alpha-synuclein dependent cell-autonomous death in neuronal and mouse models”, Neurobiol Dis, 2023 Jul:183:106166. doi: 10.1016/j.nbd.2023.106166. Epub 2023 May 26.

Comunicaciones en congresos

• Congreso: FENS Forum 2022, International Neuroscience Conference, 9-13 July, París (Póster): J.J. Bravo-González, R. Vinueza-Gavilanes, L. Larrea, L. Basurco, A Vales, G. González-Aseguinolaza, M.S. Aymerich, T. Aragón and M. Arrasate. Identifying the alpha-synuclein interactome map in a mouse model using proximitybiotinilation.
• Congreso: Synuclein Meeting 2022, Leuven, Bélgica, 12-15 de abril de 2022 en formato póster. El trabajo fue seleccionado para hacer un “flash” poster oral”: L. Basurco, M.A. Abellanas, L. Ayerra, E. Conde, R. Vinueza-Gavilanes, E. Luquin, A. Vales, A. Vilas, P. San Martin-Uriz, I. Tamayo, L. Marrodan, M.M. Alonso, M. Hernaez, G. Gonzalez-Aseguinolaza, P. Clavero, E. Mengual, M. Arrasate, S. Hervás-Stubbs, M.S. Aymerich. Regulatory T cell depletion decreases the infiltration of immune cells into the midbrain and is neuroprotective in the α-synuclein overexpression mouse model.

Parkinson’s disease (PD) is a neurodegenerative disorder that has no cure and whose primary risk factor is age. With the increase in life-expectancy, the number of people affected by the illness is predicted to increase. The histopathological features characteristic of PD are a degeneration of dopaminergic neurons of the nigrostriatal pathway, the accumulation of alpha-synuclein (aSyn) and the presence of a neuroinflammation reaction. The degeneration of the dopaminergic neurons causes a decrease in the levels of the dopamine neurotransmitter, which causes the typical motor symptoms of the disease and other very frequent non-motor symptoms. Since it was discovered in the 1960s, levodopa is still the most effective therapeutic option. Current treatments are geared towards mitigating the dopaminergic deficit to improve motor symptomatology, but they are not able to slow down the neurodegenerative process under way. Consequently, one of the major challenges in PD research is to develop therapies that protect the dopaminergic neurons and make it possible to stop the progress of the disease.

In that context, SinPARK proposes to develop innovative neuroprotection therapies for treating PD based on modulating the neuroinflammatory response and neuronal connectivity. Specifically, in this project neuroinflammation mechanisms mediated by lymphocytes and glial cells and toxic mechanisms that depend on alpha-synuclein at synaptic terminals were studied. Our methodological approach uses models that are representative of both sporadic (90-95% of cases) and family forms (mutations of aSin) (5-10%) of PD. From the regions affected by dopaminergic degeneration, we can isolate the glial cells and lymphocytes to study the neuroinflammatory profile using sequencing techniques and flow cytometry. The results obtained were validated using histological techniques. The analysis of the activation states of the glial cells in the experimental models shows a heterogeneous profile of different activation in each model, which suggests that during the neurodegenerative process there could be different states of activation of the glial depending on the stage. In the models that show an active phase of the neurodegenerative process, the microglia has a phagocytic and anti-inflammatory profile, while in the chronic model it has a pro-inflammatory profile. In contrast, the activation of the astrocytes in the mesencephalon shows a pattern of homogeneous and clearly pro-inflammatory activation in all the models, but heterogeneous in the striatum. That data indicates that in the acute phase of neuron death, a kind of inflammatory reaction is produced that varies when the neurodegeneration becomes chronic. Consequently, with a view to designing neuroprotection strategies, it is necessary to determine what the target and kind of inflammatory activity that will be modulated is. The analysis of the infiltration of lymphocytes and their state of activation once again shows us how there is high variability depending on the model in the mesencephalon, but the kind of infiltration is similar in the striatum. A common characteristic that drew our attention was the increase in the infiltration of the regulating T cells (Treg) in the mesencephalon in the models that had active neuron death. Because of that, we decided to selectively eliminate that population using transgenic animals and analyse the consequences on dopaminergic degeneration. The depletion of the Treg cells turned out to be neuroprotective in both experimental models studied. Our data suggests that the mechanism could be through blocking the entrance of T CD4 lymphocytes, myeloid cells or a decrease in TNFα production.

The aSin protein is localised in the dopaminergic terminals and their misfolding and subsequent aggregation constitutes a neuropathological characteristic in both the sporadic and familial form of the disease and one of the possible mechanisms of neuron death. In this project, we researched how the interactions that establish aSin in the initial states of its accumulation change. To those ends, we developed an in vivo (in rats) proximity biotinylation methodology that made it possible to mark the proteins that interact with the aSin with biotin.  It was possible to purify the biotinylated proteins from the mesencephalon and striatum and they were identified with mass spectrometry. In that way, it was possible to identify a specific interactome for aSin that is dependent on subcellular location, differential between the presynaptic striatum terminals and the dopaminergic soma SN. Based on those results, it is possible to evaluate the significance of those candidates in relation to the loss of synaptic connectivity.

One of the major questions in the area of synucleinopathies is whether they can be transmitted from one cell to another through the nervous system.  To answer that question, we set a technological challenge: design and administer virus in the SNpc that can express aSin fused to the fluorescent mCherry protein in a way that the expression of aSin can be traced in different areas of the brain and different kinds of cells using flow cytometry. In this project, we built those tools and we tested them in rats. Using flow cytometry, we were able to detect the fused protein localised in the dopaminergic terminals of the striatum in astrocytes and microglia, but not in oligodendrocytes or neurons. We are validating these findings using histological techniques.