title: A non-neuronal cholinergic system regulates cellular ATP levels to maintain cell viability.
abstract: OBJECTIVE
  We previously suggested that a non-neuronal cholinergic system modulates energy metabolism through the mitochondria. However, the mechanisms responsible for making this system crucial remained undetermined.
  
  
  METHODS
  In this study, we developed a fusion protein expression vector containing a luciferase gene fused to the folic acid receptor-α gene.
  
  
  RESULTS
  This protein of the vector was confirmed to target the plasma membrane of transfected HEK293 cells, and vector-derived luciferase activities and ATP levels in viable cells were positively correlated (r = 0.599). Using this luciferase vector, choline acetyltransferase (ChAT)-expressing cells (i.e., cells with an activated non-neuronal cholinergic system) had increased cellular ATP levels. ChAT-expressing cells also had upregulated IGF-1R and Glut-1 protein expressions as well as increased glucose uptake. This activated non-neuronal cholinergic system with efficient glucose metabolism rendered cells resistant to serum depletion-induced cell death.
  
  
  CONCLUSIONS
  Our results indicate that a non-neuronal cholinergic system is involved in sustaining ATP levels to render cells resistant to a nutrient-deficient environment.
authors.affiliation: Department of Physiology, Nippon Medical School Graduate School of Medicine, Tokyo, Japan.
authors.forename: Shino
authors.initials: S
authors.lastname: Oikawa
authors.forename: Mitsue
authors.initials: M
authors.lastname: Iketani
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Kakinuma
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D002470:Cell Survival; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D003470:Culture Media; D016895:Culture Media, Serum-Free; D057809:HEK293 Cells; D006801:Humans; D011950:Receptors, Cholinergic / Q000378:metabolism*
chemical_list: D003470:Culture Media; D016895:Culture Media, Serum-Free; D011950:Receptors, Cholinergic; D000255:Adenosine Triphosphate; D002795:Choline O-Acetyltransferase