Research projects

Parkinson's is a neurodegenerative disease of complex and unknown etiology. Genetic risk factors include mutations in the glucocerebrosidase-1 (GBA1) gene that confer a high predisposition to Par following objectives will be developed:

Objective 1: Generation of mature dopaminergic neurons from iPS cells derived from Parkinson's disease patients. To study the alterations caused by the N370S and L444P GBA1 mutations.

Results from Activity 1: As mentioned in previous reports, we have obtained functional dopaminergic (DA) neurons from 8 induced pluripotent stem cell lines (iPS cells or iPSCs) derived from Parkinson's patients carrying mutations in the GBA1 gene and from healthy subjects. The characteristics of the iPSCs are described in our articles (Rodríguez-Traver… Vicario, 2019a, b and Rodríguez-Traver… Vicario, 2020). This year 2020, we have a) completed the study of the effect of mutations on the morphology of dopaminergic neurons (tyrosine hydroxylase+ / TH+) analyzed with the Sholl method and b) analyzed the specific electrical responses of these neurons.

Results from Activity 2: 

A) Increase in the amount and aggregation of alpha-synuclein and changes in the neuronal distribution of this protein are neuropathological signs of Parkinson's disease. We have addressed the possible alpha-synuclein alterations in our neuronal cultures in three ways: a) quantification by ELISA of the amount of alpha-synuclein released into the culture medium; b) analysis by confocal microscopy of the presence of ectopic alpha-synuclein aggregates in dendrites and neuronal cell body, which are significantly more evident in neurons with the GBA1-N370S mutation and c) we have observed, by electron microscopy, that the two studied mutations promote the formation of neuronal inclusions similar to Lewy bodies, which we intend to characterize by immunostaining with specific antibodies. Therefore, we believe we have shown that our cultures of dopaminergic neurons (derived from iPSCs) are a good model to study Parkinson's disease at the cellular, molecular and genetic levels. Finally, we have reviewed in two articles key aspects of the pathological mechanisms of alpha-synuclein and cholesterol in Parkinson's disease (Gómez-Benito et al., 2020; García-Sanz et al., 2020).

B) The electron microscopy study has also allowed us to detect alterations in the structure of the dendrites, as well as of several organelles: Golgi apparatus, endoplasmic reticulum, mitochondria, lysosomes and autophagosomes in neurons carrying GBA1 mutations.

C) In addition, we have observed that dopamine and the D1R receptor regulate the morphology and / or density of dendritic spines of projection striatal neurons (also known as medium spiny neurons) that are innervated by dopaminergic neurons of the substantia nigra (Alberquilla et al., 2020; Suárez et al., 2020).

Objective 2 : Rescue of the possible phenotype attributable to mutations in GBA1 by the application of molecules with chaperone activity.

Results from Activity 4 : We have carried out experiments with the objective of correcting or rescuing alterations in alpha synuclein by incubating neuronal cultures with ambroxol and arimoclomol. These molecules possess chaperone activity and can increase glucosylceramidase activity, so they would be candidates to prevent and / or reduce neurodegeneration caused by GBA1 mutations. Although we have analyzed and quantified a large part of the results obtained, we have yet to complete all the work in the coming months.