THERAPY OPTIONS THD

Neurotransmitter synthesis disorders: towards a therapeutic correction

 Partecipanti

Mappa

 Word cloud

Esplora la "nuvola delle parole (Word Cloud) per avere un'idea di massima del progetto.

 Obiettivo del progetto (Objective)

'The present postdoctoral project to be carried out by Dr. Ana Jorge Finnigan at the Department of Biomedicine, University of Bergen, is integrated in the research programs carried out at Research group Biorecognition, leaded by Professor Aurora Martinez. The postdoctoral project integrates methods spanning the structural and functional characterization of complexes of tyrosine hydroxylase (TH) with proteins and membranes, and the regulation of the activity and localization of TH by small ligands, both in cells and animal models. The activities are organized in an interdisciplinary set-up of expertise and methodology managed by the applicant lab and a network of collaborators. TH catalyzes the hydroxylation of L-Tyr to DOPA, the rate-limiting step in the synthesis of catecholamine neurotransmitters and hormones in brain and neuroendocrine tissues. Due to the high relevance of well-regulated catecholamine synthesis and protein-membrane interactions in human health and neurological disease, the project is expected to contribute with novel understanding of pathogenic mechanism affecting TH stability and regulation as well as with novel therapeutic approaches aiming correction of TH misfolding and mislocalization. The therapuetical tools developed through this project may even be of application to social burden diseases such as Parkinson's disease.'

Introduzione (Teaser)

Several neurodegenerative disorders, including Parkinson's disease, are associated with dysfunctions of the dopamine system. Understanding dopamine synthesis regulation will facilitate exploration of new therapeutic options for such diseases, affecting millions of people worldwide.

Descrizione progetto (Article)

The symptoms of Parkinson's disease result from the death of dopamine-generating cells in the brain and a decline in the enzyme tyrosine hydroxylase (TH). TH is a key enzyme, catalysing the conversion of L-tyrosine to L-3,4-dihydroxyphenylalanine (L-DOPA). L-DOPA is in turn converted to dopamine, a precursor for the other catecholamine neurotransmitters and hormones in the brain and neuroendocrine tissues. Decrease in TH is also associated with other neuropsychiatric diseases such as manic depressive illness, schizophrenia or L-DOPA-responsive dystonia.

Funded by the EU, the project THERAPY OPTIONS THD (Neurotransmitter synthesis disorders: Towards a therapeutic correction) was dedicated to further understand TH regulation. Scientists focused on the effect of TH phosphorylation and its binding to partner proteins and membranes. Phosphorylation of TH is a complex process, affecting four different residues. To understand the roles of each phosphorylation site, cellular localisation of different phosphorylated forms of TH was characterised.

Confocal microscopy analysis revealed co-distribution of each phosphorylated form with different partner proteins in neuroendocrine and neuroblastoma cell line cultures as well as in human dopaminergic neurons. The project identified specific and clear differences in the subcellular localisation of each TH species. In addition, using biophysical approaches such as cell-substrate impedance and flow cytometry allowed analysis of the effect of TH on the synthetic membranes.

Finally, the screening a library of pharmacological compounds by differential scanning fluorimetry led to the identification of 17 compounds interacting with TH. These compounds were studied in wild-type TH and as well as in TH mutants associated with the neurological disorder TH deficiency (THD). In all cases the compounds protected from time-dependent loss of activity. Two of the identified compounds resulted in increased TH activity in the cells transfected with either wild-type TH or THD-associated mutants without affecting steady-state TH protein levels.

Advancing understanding of the mechanisms affecting TH and dopamine synthesis regulation is an important step to address the diseases caused by TH dysfunction.