title: Immortalized dopamine neurons: A model to study neurotoxicity and neuroprotection.
abstract: 6-Hydroxydopamine (6-OHDA) causes selective degeneration of dopaminergic neurons in the rat brain and has been used to produce an animal model of Parkinsonism. Recently, a clonal line of immortalized dopamine (DA) neurons (1RB3AN27), which expresses varying levels of tyrosine hydroxylase, dopamine transporter, neuron specific enolase, and nestin, was established. These DA neurons reduce behavioral deficits in 6-OHDA-lesioned rats. The relative sensitivity of fetal and adult neurons to potential neurotoxins is not well defined. The availability of immortalized DA neurons provides a unique opportunity to compare the relative neurotoxicity of 6-OHDA in differentiated and undifferentiated DA neurons in vitro and identify neuroprotective agents. Our results showed that 6-OHDA treatment for 24 hr decreased the viability of undifferentiated and differentiated immortalized DA neurons in vitro, as determined by the MTT assay, and increased the rate of apoptosis in differentiated DA neurons. The differentiated DA neurons (IC50 = 33 microM) were about 2-fold more sensitive to 6-OHDA than undifferentiated DA neurons (IC50 = 75 microM) in cell culture. Similarly, the differentiated DA neurons were more sensitive to another neurotoxin, 1-methyl-4-phenylpyridinium (MPP+), which is commonly used to induce Parkinsonism in animal models, than were the undifferentiated DA neurons in culture. Among growth factors tested, only glial cell line-derived neurotrophic factor (GDNF) partially protected differentiated DA neurons against 6-OHDA-induced toxicity. These results suggest that undifferentiated and differentiated immortalized DA neurons can be a useful experimental model to study relative sensitivity to neurotoxins and neuroprotective agents that could have relevance to fetal and adult neurons.
authors.affiliation: Center for Vitamins, Department of Medicine, University of Colorado Health Sciences Center, Denver 80262, USA.
authors.forename: E D
authors.initials: ED
authors.lastname: Clarkson
authors.forename: J
authors.initials: J
authors.lastname: Edwards-Prasad
authors.forename: C R
authors.initials: CR
authors.lastname: Freed
authors.forename: K N
authors.initials: KN
authors.lastname: Prasad
mesh_terms: D015655:1-Methyl-4-phenylpyridinium / Q000494:pharmacology*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001921:Brain / Q000166:cytology / Q000502:physiology; D002454:Cell Differentiation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002999:Clone Cells; D004298:Dopamine / Q000502:physiology*; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D051100:Glial Cell Line-Derived Neurotrophic Factor; D006133:Growth Substances / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins / Q000494:pharmacology; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D018696:Neuroprotective Agents / Q000494:pharmacology*; D009498:Neurotoxins / Q000494:pharmacology*; D016627:Oxidopamine / Q000494:pharmacology*; D051381:Rats; D011994:Recombinant Proteins / Q000494:pharmacology
chemical_list: C495041:Gdnf protein, rat; D051100:Glial Cell Line-Derived Neurotrophic Factor; D006133:Growth Substances; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D018696:Neuroprotective Agents; D009498:Neurotoxins; D011994:Recombinant Proteins; D016222:Fibroblast Growth Factor 2; D007334:Insulin-Like Growth Factor I; D016627:Oxidopamine; D015655:1-Methyl-4-phenylpyridinium; D004298:Dopamine