PMID- 15661660
OWN - NLM
STAT- MEDLINE
DCOM- 20050711
LR  - 20211102
IS  - 1568-7864 (Print)
IS  - 1568-7856 (Linking)
VI  - 4
IP  - 3
DP  - 2005 Mar 2
TI  - The multifunctional DNA repair/redox enzyme Ape1/Ref-1 promotes survival of 
      neurons after oxidative stress.
PG  - 367-79
AB  - Although correlative studies demonstrate a reduction in the expression of 
      apurinic/apyrimidinic endonuclease/redox effector factor (Ape1/Ref-1 or Ape1) in 
      neural tissues after neuronal insult, the role of Ape1 in regulating 
      neurotoxicity remains to be elucidated. To address this issue, we examined the 
      effects of reducing Ape1 expression in primary cultures of hippocampal and 
      sensory neurons on several endpoints of neurotoxicity induced by H2O2. Ape1 is 
      highly expressed in hippocampal and sensory neurons grown in culture as indicated 
      by immunohistochemistry, immunoblotting and activity. Exposing hippocampal or 
      sensory neuronal cultures to 25 or 50 nM small interfering RNA to Ape1 
      (Ape1siRNA), respectively, for 48 h, causes a reduction in immunoreactive Ape1 by 
      approximately 65 and 54%, and an equivalent loss in endonuclease activity. The 
      reduced expression of Ape1 is maintained for up to 5 days after the siRNA in the 
      medium is removed, whereas exposing cultures to scrambled sequence siRNA 
      (SCsiRNA) has no effect of Ape1 protein levels. The reduction in Ape1 
      significantly reduces cell viability in cultures 24 h after a 1-h exposure to 
      25-300 microM H2O2, compared to SCsiRNA treated controls. In cells treated with 
      SCsiRNA, exposure to 300 microM H2O2 reduced cell viability by 40 and 30% in 
      hippocampal and sensory neuronal cultures, respectively, whereas cultures treated 
      with Ape1siRNA lost 93 and 80% of cells after the peroxide. Reduced Ape1 levels 
      also increase caspase-3 activity in the cells, 2-3-fold, 60min after a 1-h 
      exposure to 100 microM H2O2 in the cultures. Exposing neuronal cultures with 
      reduced expression of Ape1 to 65 microM H2O2 (hippocampal) or 300 microM H2O2 
      (sensory) for 1h results in a 3-fold and 1.5-fold increase in the phosphorylation 
      of histone H2A.X compared to cells exposed to SCsiRNA. Overexpressing wild-type 
      Ape1 in hippocampal and sensory cells using adenoviral expression constructs 
      results in significant increase in cell viability after exposure to various 
      concentrations of H2O2. The C65A repair competent/redox incompetent Ape1 when 
      expressed in the hippocampal and sensory cells conferred only partial protection 
      on the cells. These data support the notion that both of functions of Ape1, redox 
      and repair are necessary for optimal levels of neuronal cell survival.
FAU - Vasko, Michael R
AU  - Vasko MR
AD  - Department of Pharmacology and Toxicology, Indiana University School of Medicine, 
      1044 W. Walnut, Room 302C, Indianapolis, IN 46202, USA.
FAU - Guo, Chunlu
AU  - Guo C
FAU - Kelley, Mark R
AU  - Kelley MR
LA  - eng
GR  - 1RO1 NS 38506/NS/NINDS NIH HHS/United States
GR  - 1RO1 NS34159/NS/NINDS NIH HHS/United States
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - Netherlands
TA  - DNA Repair (Amst)
JT  - DNA repair
JID - 101139138
RN  - 0 (RNA, Small Interfering)
RN  - BBX060AN9V (Hydrogen Peroxide)
RN  - EC 4.2.99.18 (Apex1 protein, rat)
RN  - EC 4.2.99.18 (DNA-(Apurinic or Apyrimidinic Site) Lyase)
SB  - IM
MH  - Animals
MH  - Base Sequence
MH  - Blotting, Western
MH  - Cell Survival/*physiology
MH  - Cells, Cultured
MH  - *DNA Repair
MH  - DNA-(Apurinic or Apyrimidinic Site) Lyase/*physiology
MH  - Hydrogen Peroxide/pharmacology
MH  - Immunohistochemistry
MH  - Neurons/*cytology/drug effects
MH  - Oxidation-Reduction
MH  - *Oxidative Stress
MH  - RNA, Small Interfering/chemistry
MH  - Rats
EDAT- 2005/01/22 09:00
MHDA- 2005/07/12 09:00
CRDT- 2005/01/22 09:00
PHST- 2004/09/20 00:00 [received]
PHST- 2004/11/09 00:00 [accepted]
PHST- 2005/01/22 09:00 [pubmed]
PHST- 2005/07/12 09:00 [medline]
PHST- 2005/01/22 09:00 [entrez]
AID - S1568-7864(04)00342-8 [pii]
AID - 10.1016/j.dnarep.2004.11.006 [doi]
PST - ppublish
SO  - DNA Repair (Amst). 2005 Mar 2;4(3):367-79. doi: 10.1016/j.dnarep.2004.11.006.