Nuclear translocation of glyceraldehyde-3-phosphate dehydrogenase: a role in high glucose-induced apoptosis in retinal Müller cells.
OBJECTIVE
A recent study demonstrated that retinal Müller cells undergo hyperglycemia-induced apoptosis in vitro. Translocation of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from the cytosol to the nucleus is a critical step in the induction of apoptosis in neuronal cells. R-(-)-deprenyl prevents nuclear translocation of GAPDH and subsequent apoptosis in neuronal cells. In this study, the role of nuclear translocation of GAPDH in hyperglycemia-induced apoptosis in retinal Müller cells and the ability of R-(-)-deprenyl to inhibit the translocation of GAPDH and apoptosis were investigated.


METHODS
Transformed rat Müller cells (rMC-1) and isolated human Müller cells were cultured in normal glucose, high glucose, and high glucose plus R-(-)-deprenyl for up to 5 days. Subcellular distribution of GAPDH was determined in vitro and in vivo by immunocytochemistry. Apoptosis in tissue cultures was determined by annexin-V staining and caspase-3 activity.


RESULTS
Hyperglycemia significantly increased the amount of GAPDH protein in the nucleus above normal within the first 48 hours in rMC-1 and human Müller cells. The addition of R-(-)-deprenyl to these cells incubated in high glucose reduced the amount of GAPDH protein in the nucleus and decreased hyperglycemia-induced apoptosis in both cell types. In vivo studies confirmed the accumulation of GAPDH in nuclei of Müller cells in diabetes.


CONCLUSIONS
The nuclear translocation of GAPDH in rMC-1 and human Müller cells is closely associated with the induction of apoptosis. R-(-)-deprenyl inhibits nuclear accumulation of GAPDH and subsequent apoptosis in these cells. Therefore, R-(-)-deprenyl offers a strategy to explore the role of GAPDH translocation into the nucleus in the development of diabetic retinopathy.
Kusner
Linda L
LL
Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio, USA.
Sarthy
Vijay P
VP
Mohr
Susanne
S
D021581:Active Transport, Cell Nucleus; D000328:Adult; D000818:Animals; D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002467:Cell Nucleus / Q000201:enzymology*; D002478:Cells, Cultured; D003593:Cytoplasm / Q000201:enzymology; D005947:Glucose / Q000494:pharmacology*; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000502:physiology*; D006801:Humans; D006943:Hyperglycemia / Q000503:physiopathology; D008297:Male; D018613:Microscopy, Confocal; D008996:Monoamine Oxidase Inhibitors / Q000494:pharmacology; D009457:Neuroglia / Q000201:enzymology*; D051381:Rats; D012160:Retina / Q000166:cytology*; D012642:Selegiline / Q000494:pharmacology
D017304:Annexin A5; D008996:Monoamine Oxidase Inhibitors; D012642:Selegiline; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; C505407:CASP3 protein, human; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases; D005947:Glucose