Project: Improvement of differentiation and survival rate of transplanted dopaminergic neurons via secreted neurotrophic factors (EU, MWK-Niedersachsen for Prof. Dr. Claufia Grothe)

Parkinson´s disease is a neurodegenerative disorder, caused by a progressive loss of dopaminergic neurons in the substantia nigra. One possible treatment is a curative cell therapy, in which new dopaminergic cells are implanted into the striatum. The quality of the transplants can be further improved by applying neurotrophic factors. Some of those secreted factors such as FGF8b, SHH, WNT1 are known to regulate dopaminergic neurogenesis during embryonic development.

Our group investigates the differentiation of neuronal progenitor cells (isolated from rat embryos) towards dopaminergic neurons initially in vitro. Genetic modification of those cells either by transfection or nucleofection with suitable expression plasmids (Cesnulevicius et al. 2006 Stem Cell 24: 2776), allows studying the effects of single or a combination of neurotrophic factors. Utilisation of a different promoter resulted in an improved expression level of such factors, or as shown in the figure of the enhanced green fluorescent protein (EGFP), in vitro and also in vivo.

A similar approach, co-transplantation of FGF2 transfected Schwann cells and dopaminergic neurons, showed an improved functionality of the transplants in vivo (Timmer et al. 2004 Exp. Neurol. 187: 118). For such experiments we are using an animal model of Parkinson´s disease, more precisely the unilateral 6-OHDA-lesioned rat model (Timmer et al. 2006 Neurobiol. Dis. 21: 587).

Project: Relevance of the FGF system for the development of dopaminergic neurons in the midbrain
(DFG for Prof. Dr. Claudia Grothe)

Previous investigation of adult mouse mutants defective for fibroblast growth factor 2 (FGF2) or FGF-receptor 3 (FGFR3) revealed differences in the volume of the substantia nigra and the cell number of dopaminergic neurons (Timmer et al. 2007 J. Neurosci. 27: 459). In continuation of this work we analyse the development of the substantia nigra during embryonic (E14), newborn (P0) and postnatal stages with several approaches.

First, the substantia nigra is morphometrically evaluated; therefore tyrosin hydroxylase (TH) immunoreactive neurons were quantified on serial sections of the brain. Furthermore the mouse mutants will be characterized by the aid of several molecular biological techniques such as quantitative RT-PCR, in-situ hybridisation and western blot.

Second, a cell culture model of the ventral mesencephalon is used to compare the different mouse mutants. Besides FGF2 several other FGFs (e.g. FGF8b) are known to regulate dopaminergic differentiation (for review see Grothe und Timmer 2007 Brain Res. Rev. 54: 80). By adding growth factors (as recombinant protein or via transfection with suitable expression plasmids) we investigate their relevance for the dopaminergic differentiation in vitro.