The discovery of a dopamine (DA) deficiency in the brain of patients with Parkinson's disease (PD) represents a milestone in both clinical and basic neuroscience. The reason for the DA deficiency is a progressive degeneration of DA neurons in the basal ganglia (by an unknown mechanism) and a lowering of tyrosine hydroxylase (TH) activity in these neurons. The beneficial effect of L-DOPA therapy on PD, which partially and transiently compensates DA deficiency, opened up a new area of pharmacological treatment for PD. Transplantation of hybrid cell lines producing DA may represent an alternative treatment.
A main objective is to generate hybrid transplantable cells expressing a DAergic phenotype, with the goal to replace degenerated DAergic neurons, as well as a pharmacological modulation of the biosynthesis, storage and release of DA. The methods employed have been those pertaining to molecular biology, biochemistry, biophysics and cell biology.
Specific enzymological studies on the tyrosine hydroxylase system, the rate-limiting enzyme in the biosynthesis of dopamine/noradrenaline (DA/NA), have been undertaken. The research includes studies on the structure, relation between structure and function, and the catalytic mechanism of the four recombinant human TH isozymes and mutant forms expressed in E. coli (A, B and C). Specific aspects of the cellular biosynthesis, storage and release of DA have been studied (B and C). The biogenesis of the secretory granules storing DA, including their maturation, after budding from the trans-Golgi network, and reutilization following exocytosis have been studied in PC12 cells (B). Efforts have been made to develop transplantable hybrid cell lines, expressing the key phenotypic properties of DAergic neurons, which can survive, make phenotypic plasticity, synthesize/release DA, and ameliorate motor dysfunction (C). New derivatives of tetrahydrobiopterin with improved cofactor properties in the tyrosine hydroxylase reaction have been designed, synthesized and tested on the isoforms of human TH and the hybrid cell lines (B, C and D).
Funding SchemeCON - Coordination of research actions