title: Vitamin B12-impaired metabolism produces apoptosis and Parkinson phenotype in rats expressing the transcobalamin-oleosin chimera in substantia nigra.
abstract: BACKGROUND
  Vitamin B12 is indispensable for proper brain functioning and cytosolic synthesis of S-adenosylmethionine. Whether its deficiency produces effects on viability and apoptosis of neurons remains unknown. There is a particular interest in investigating these effects in Parkinson disease where Levodopa treatment is known to increase the consumption of S-adenosylmethionine. To cause deprivation of vitamin B12, we have recently developed a cell model that produces decreased synthesis of S-adenosylmethionine by anchoring transcobalamin (TCII) to the reticulum through its fusion with Oleosin (OLEO).
  
  
  METHODS
  Gene constructs including transcobalamin-oleosin (TCII-OLEO) and control constructs, green fluorescent protein-transcobalamin-oleosin (GFP-TCII-OLEO), oleosin-transcobalamin (OLEO-TCII), TCII and OLEO were used for expression in N1E-115 cells (mouse neuroblastoma) and in substantia nigra of adult rats, using a targeted transfection with a Neurotensin polyplex system. We studied the viability and the apoptosis in the transfected cells and targeted tissue. The turning behavior was evaluated in the rats transfected with the different plasmids.
  
  
  RESULTS
  The transfection of N1E-115 cells by the TCII-OLEO-expressing plasmid significantly affected cell viability and increased immunoreactivity of cleaved Caspase-3. No change in propidium iodide uptake (used as a necrosis marker) was observed. The transfected rats lost neurons immunoreactive to tyrosine hydroxylase. The expression of TCII-OLEO was observed in cells immunoreactive to tyrosine hydroxylase of the substantia nigra, with a superimposed expression of cleaved Caspase-3. These cellular and tissular effects were not observed with the control plasmids. Rats transfected with TCII-OLEO expressing plasmid presented with a significantly higher number of turns, compared with those transfected with the other plasmids.
  
  
  CONCLUSIONS
  In conclusion, the TCII-OLEO transfection was responsible for apoptosis in N1E-115 cells and rat substantia nigra and for Parkinson-like phenotype. This suggests evaluating whether vitamin B12 deficit could aggravate the PD in patients under Levodopa therapy by impairing S-adenosylmethionine synthesis in substantia nigra.
authors.affiliation: Department of Physiology, Biophysics and Neuroscience, Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Mexico City, Mexico.
authors.forename: Carlos Enrique
authors.initials: CE
authors.lastname: Orozco-Barrios
authors.forename: Shyue-Fang
authors.initials: SF
authors.lastname: Battaglia-Hsu
authors.forename: Martha Ligia
authors.initials: ML
authors.lastname: Arango-Rodriguez
authors.forename: Jose
authors.initials: J
authors.lastname: Ayala-Davila
authors.forename: Celine
authors.initials: C
authors.lastname: Chery
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Alberto
authors.forename: Henry
authors.initials: H
authors.lastname: Schroeder
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Daval
authors.forename: Daniel
authors.initials: D
authors.lastname: Martinez-Fong
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Gueant
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001522:Behavior, Animal / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D006801:Humans; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D008694:Methamphetamine / Q000494:pharmacology; D051379:Mice; D009336:Necrosis; D010300:Parkinson Disease / Q000473:pathology*; D010940:Plant Proteins / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics; D021381:Protein Transport / Q000187:drug effects; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000378:metabolism*; D013378:Substantia Nigra / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D014155:Transcobalamins / Q000378:metabolism*; D014162:Transfection; D019076:Transgenes / Q000235:genetics; D014805:Vitamin B 12 / Q000378:metabolism*
chemical_list: D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D014155:Transcobalamins; D008694:Methamphetamine; D014805:Vitamin B 12