Loss of redox factor 1 decreases NF-kappaB activity and increases susceptibility of endothelial cells to apoptosis.
OBJECTIVE
The aim of this project was to test the hypothesis that redox factor 1 (Ref-1) was a critical upstream determinant of NF-kappaB-dependent survival signaling pathways in the vessel wall.


RESULTS
Aortas from hemizygous transgenic mice harboring a single allele of Ref-1 exhibited a significant loss in NF-kappaB DNA binding activity. The NF-kappaB-dependent survival gene A20 was significantly downregulated in aortas of hemizygous Ref-1 mice, whereas IAP-2 was unchanged. Overexpression of A20 rescued cells from tumor necrosis factor (TNF)-induced apoptosis, suggesting that the loss of A20 in Ref-1 hemizygotes may be a rate-determining step in endothelial cell fate. Deletion of the previously defined redox-sensitive or the AP endonuclease domains of Ref-1 significantly decreased NF-kappaB transcriptional activation and endothelial cell survival. Furthermore, TNF-induced apoptosis was significantly potentiated in endothelial cells after delivery of Morpholino antisense oligodeoxynucleotides targeted to Ref-1. Loss of the redox-sensitive domain blocked the ability of Ref-1 to reduce p50; however, loss of the endonuclease domain did not effect p50 reduction, suggesting alternative mechanisms of action of Ref-1 on NF-kappaB activity.


CONCLUSIONS
These findings establish a role for Ref-1 as an upstream determinant of NF-kappaB and A20-dependent signaling and endothelial survival in the vessel wall.
Guan
Zhanjun
Z
Lillehei Heart Institute, University of Minnesota, Minneapolis, MN 55455, USA.
Basi
David
D
Li
Qinglu
Q
Mariash
Ami
A
Xia
Yi-Feng
YF
Geng
Jian-Guo
JG
Kao
Esther
E
Hall
Jennifer L
JL
D000818:Animals; D001011:Aorta; D017209:Apoptosis / Q000502:physiology*; D002417:Cattle; D002460:Cell Line; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase / Q000172:deficiency* / Q000502:physiology; D042783:Endothelial Cells / Q000473:pathology*; D004730:Endothelium, Vascular / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D016328:NF-kappa B / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
D016328:NF-kappa B; C085108:APEX1 protein, human; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase