THE USE OF EMBRYONIC PRIMATE STEM CELLS IN PARKINSON?S DISEASE MODELS

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Parthenogenetic stem cells might become a valid alternative to fetal tissue for transplantation in human patients if appropriate neuronal differentiation and integration are shown in vivo. In this study we will investigate the efficacy of parthenogenetic primate stem cells (Cyno-1, Cibelli et al 2002) to restore motor function in animal models of PD. Cyno-1 cells can be maintained and expanded for long periods of time and using appropriate protocols 80% differentiate into neurons in vitro. Twenty-five percent of these neurons express tyrosine hydroxylase (TH) and release dopamine (DA) in response to KCl depolarization (Cibelli et al, 2002). In this study we will investigate the potential of these cells to differentiate in vivo into DA neurons. Initial studies will be performed in the 6-OHDA-lesioned rat model to optimize the in vivo conditions. We have already obtained successful DA differentiation using mice stem cells in this model (Bjokrlund et al, 2002). Primate studies are critical to evaluate the functional efficacy of stem cell derived DA neurons. In this study donor and host are from the same species, which minimizes immunological problems but in order to identify grafted cells we will use GFP expressing Cyno-1 cells. GFP expression did not alter mouse ES cells differentiation into DA neurons in the mouse. Moreover, we will transplant into male host so we will use in situ hybridization (FISH) for the Y chromosome to differentiate TH neurons derived from Cyno-1 (parthenogenetic) from host derived TH-intrinsic striatal neurons. We will combine behavioral and functional neuroimaging techniques to determine recovery of motor signs in correlation with graft maturation and integration, which we assess in vivo using positron emission tomography (PET) and specific ligands for pre and postsynaptic DA markers.