Ventral tegmental area dopamine neurons are resistant to human mutant alpha-synuclein overexpression.
Parkinson's disease (PD) is characterized by the formation of intracytoplasmic inclusions, which contain alpha-synuclein (alpha-syn) protein. While most profound neurodegeneration is seen in the dopamine (DA) synthesizing neurons located in the ventral midbrain, it is unclear why some DA cell groups are more susceptible than others. In the midbrain, the degeneration of the substantia nigra (SN) DA neurons is severe, whereas the involvement of the ventral tegmental area (VTA) neurons is relatively spared. In the present study, we overexpressed human A53T alpha-syn in the VTA neurons and found that A53T toxicity did not affect their survival. There was, however, a mild functional impairment seen as altered open field locomotor activity. Overexpression of A53T in the SN, on the other hand, led to profound cell loss. These results suggest that the selective susceptibility of nigral DA neurons is at least in part associated with factor(s) involved in handling of alpha-syn that is not shared by the VTA neurons. Secondly, these results highlight the fact that impaired but surviving neurons can have a substantial impact on DA-dependent behavior and should therefore be considered as a critical part of animal models where novel therapeutic interventions are tested.
Maingay
Matthew
M
Department of Experimental Medical Science, Section of Neuroscience, CNS Disease Modeling Unit, Lund University, Wallenberg Neuroscience Center, BMCA11, S-22184 Lund, Sweden. matthew.maingay@med.lu.se
Romero-Ramos
Marina
M
Carta
Manolo
M
Kirik
Deniz
D
D000818:Animals; D000229:Dependovirus / Q000235:genetics; D004195:Disease Models, Animal; D004298:Dopamine / Q000378:metabolism*; D005260:Female; D015870:Gene Expression / Q000502:physiology; D020022:Genetic Predisposition to Disease / Q000235:genetics; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D002479:Inclusion Bodies / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D009154:Mutation / Q000235:genetics; D009410:Nerve Degeneration / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D009474:Neurons / Q000378:metabolism* / Q000473:pathology; D010300:Parkinson Disease / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013378:Substantia Nigra / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism; D015854:Up-Regulation / Q000502:physiology; D017557:Ventral Tegmental Area / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D051844:alpha-Synuclein / Q000235:genetics / Q000378:metabolism / Q000633:toxicity*
D051844:alpha-Synuclein; D014446:Tyrosine 3-Monooxygenase; D004298:Dopamine