Overexpression of HA-Bax but not Bcl-2 or Bcl-X(L) attenuates 6- hydroxydopamine-induced neuronal apoptosis

Jae H. Oh, Won Seok Choi, Ji Eun Kim, Jung Woo Seo, Karen L. O'Malley, Young J. Oh

Research output: Contribution to journalArticlepeer-review

32 Scopus citations

Abstract

Bax, a member of the Bcl-2 gene family, is known to promote apoptosis in many cases but to block cell death under certain conditions. To investigate the potential role of Bax in 6-hydroxydopamine (6-OHDA)-induced cell death, we first established and characterized a dopaminergic neuronal cell line (MN9D) stably overexpressing hemagglutinin epitope-tagged Bax (MN9D/HA-Bax) as well as control clones (MN9D/Neo). Treatment of MN9D/Neo cells with 6- OHDA induced typical apoptotic cell death accompanied by shrinkage of the cell, nuclear condensation, and DNA fragmentation as demonstrated by light microscopy and agarose gel analysis. Overexpression of HA-Bax in MN9D cells was shown to attenuate 6-OHDA-induced cell death as determined by the MTT reduction assay and agarose gel analysis for DNA fragmentation. Western blot analysis revealed that cleavage of poly(ADP-ribose)polymerase induced by 6- OHDA was attenuated in MN9D/HA-Bax cells. In contrast, overexpression of a well-known cell death-inhibiting protein such as Bcl-2 or Bcl-X(L) did not attenuate 6-OHDA-induced cell death. Interestingly, cell death induced by hydrogen peroxide (0.25-2.0 mM) was significantly accelerated, whereas the rate of cell death induced by menadione (10-50 μM) was not affected in MN9D/HA-Bax cells. Thus, our present data suggest that the functionally diverse roles of Bax may be determined by the type of stress applied to the cell.

Original languageEnglish
Pages (from-to)193-198
Number of pages6
JournalExperimental Neurology
Volume154
Issue number1
DOIs
StatePublished - Nov 1998

Keywords

  • 6-hydroxydopamine
  • Apoptosis
  • Bax
  • Caspase
  • Dopaminergic neuron

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