Embryonic stem cell-derived neural progenitors as non-tumorigenic source for dopaminergic neurons

AIM:To find a safe source for dopaminergic neurons,we generated neural progenitor cell lines from human embryonic stem cells.METHODS:The human embryonic stem(hES)cell line H9 was used to generate human neural progenitor(HNP)cell lines.The resulting HNP cell lines were differentiated into dopaminergic neurons and analyzed by quantitative real-time polymerase chain reaction and immunofluorescence for the expression of neuronal differentiation markers,including beta-III tubulin(TUJ1)and tyrosine hydroxylase(TH).To assess the risk of teratoma or other tumor formation,HNP cell lines and mouse neuronal progenitor(MNP)cell lines were injected subcutaneously into immunodeficient SCID/beige mice.RESULTS:We developed a fairly simple and fast protocol to obtain HNP cell lines from hES cells.These cell lines,which can be stored in liquid nitrogen for several years,have the potential to differentiate in vitro into dopaminergic neurons.Following day 30 of differentiation culture,the majority of the cells analyzed expressed the neuronal marker TUJ1 and a high proportion of these cells were positive for TH,indicating differentiation into dopaminergic neurons.In contrast to H9 ES cells,the HNP cell lines did not form tumors in immunodeficient SCID/beige mice within 6 mo after subcutaneous injection.Similarly,no tumors developed after injection of MNP cells.Notably,mouse ES cells or neuronal cells directly differentiated from mouse ES cells formed teratomas in more than 90%of the recipients.CONCLUSION:Our findings indicate that neural progenitor cell lines can differentiate into dopaminergic neurons and bear no risk of generating teratomas or other tumors in immunodeficient mice.

No association between Parkinson disease and autoantibodies against NMDA-type glutamate receptors

Background:IgG-class autoantibodies to N-Methyl-D-Aspartate(NMDA)-type glutamate receptors define a novel entity of autoimmune encephalitis.Studies examining the prevalence of NMDA IgA/IgM antibodies in patients with Parkinson disease with/without dementia produced conflicting results.We measured NMDA antibodies in a large,well phenotyped sample of Parkinson patients without and with cognitive impairment(n=296)and controls(n=295)free of neuropsychiatric disease.Detailed phenotyping and large numbers allowed statistically meaningful correlation of antibody status with diagnostic subgroups as well as quantitative indicators of disease severity and cognitive impairment.Methods:NMDA antibodies were analysed in the serum of patients and controls using well established validated assays.We used anti-NMDA antibody positivity as the main independent variable and correlated it with disease status and phenotypic characteristics.Results:The frequency of NMDA IgA/IgM antibodies was lower in Parkinson patients(13%)than in controls(22%)and higher than in previous studies in both groups.NMDA IgA/IgM antibodies were neither significantly associated with diagnostic subclasses of Parkinson disease according to cognitive impairment,nor with quantitative indicators of disease severity and cognitive impairment.A positive NMDA antibody status was positively correlated with age in controls but not in Parkinson patients.Conclusion:It is unlikely albeit not impossible that NMDA antibodies play a significant role in the pathogenesis or progression of Parkinson disease e.g.to Parkinson disease with dementia,while NMDA IgG antibodies define a separate disease of its own.