Association of Increased Bcl‐2 Expression with Rescue from Tumor Necrosis Factor‐α‐Induced Cell Death in the Oligodendrocyte Cell Line OLN‐93

Burgmaier, Gruscha; Schönrock, Lisa M.; Kuhlmann, Tanja; Richter‐Landsberg, Christiane; Brück, Wolfgang

Abstract: The present study investigated the effects of flupirtine(Katadolon) on tumor necrosis factor (TNF)‐α‐mediated cell death andBcl‐2 expression in the permanent rat oligodendrocyte cell line OLN‐93 (OLNcells). TNF‐α (500 U/ml) induced apoptosis of OLN cells, which wasconfirmed by DNA fragmentation using an in situ end‐labeling technique andultrastructural analysis. Flupirtine significantly reduced the rate ofspontaneous cell death of OLN cells already at low concentrations;TNF‐α‐mediated apoptosis was suppressed only with higher concentrationsof flupirtine (100 μM). Expression of Bcl‐2 protein and mRNA inOLN cells was detected by immunocytochemistry, western blot, and RT‐PCR.Quantitative analysis of western blots revealed an ∼2.5‐fold up‐regulationof Bcl‐2 protein during TNF‐α treatment. Furthermore, addition of 10 or100 μM flupirtine before incubation with TNF‐α led to anapproximately threefold increase of Bcl‐2 expression. Exposure of OLN cells toflupirtine alone moderately augmented the expression of Bcl‐2 protein. Ourdata demonstrate that flupirtine up‐regulates the expression of Bcl‐2 proteinin OLN cells; this Bcl‐2 induction is associated with a reduced rate ofTNF‐α‐induced cell death.