Abstract
Background. Sustained overproduction of nitric oxide and peroxynitrite (ONOO-) in conditions such as necrotizing enterocolitis and inflammatory bowel disease may promote gut barrier failure by inducing enterocyte apoptosis. NF-κB is upregulated in the gut during inflammation and, in addition to its proinflammatory effects, may upregulate protective or anti-apoptotic factors such as inhibitor of apoptosis proteins (IAPs). We have previously demonstrated that NF-κB inhibition increases cytokine-induced enterocyte apoptosis; however, the effect of NF-κB on ONOO--induced enterocyte apoptosis is unknown. Materials and methods. Rat intestinal epithelial cells (IEC-6) were transfected with the adenoviral vector AdIκB or AdlacZ. AdIκB contains a mutated form of IκB which functions as a superrepressor of NF-κB. Cells were then treated with 50 μM ONOO- or decomposed ONOO-. Apoptosis was then determined by flow cytometry with annexin V-FITC and propidium iodide staining. Caspase activation and IAP, Bcl-2, Bad, and Bax expression were examined using Western blot analysis, and NF-κB activation was determined via electrophoretic mobility shift assay (EMSA). Results. Inhibition of NF-κB with AdIκB significantly enhanced ONOO--induced apoptosis in IEC-6 cells. ONOO- treatment did not activate NF-κB in IEC-6 cells as determined by EMSA. There was no difference in IAP, Bcl-2, Bad, and Bax expression between nontransfected, AdlacZ-transfected, and AdIκB-transfected cells. Baseline procaspase 3 activation was increased in AdIκB-transfected cells. Conclusions. NF-κB inhibition enhances ONOO--induced enterocyte apoptosis, suggesting that NF-κB upregulates a protective factor. This protective factor does not appear to be an IAP or Bcl-2 family member and may be expressed constitutively, since ONOO- did not activate NF-κB over baseline levels of activation.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 7-14 |
| Number of pages | 8 |
| Journal | Journal of Surgical Research |
| Volume | 106 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 1 2002 |
| Externally published | Yes |
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Keywords
- Apoptosis
- Caspases
- Enterocyte
- Inhibitor of apoptosis proteins
- NF-κB
- Peroxynitrite
ASJC Scopus subject areas
- Surgery
Cite this
NF-κB inhibition enhances peroxynitrite-induced enterocyte apoptosis. / Potoka, Douglas A.; Upperman, Jeffrey S.; Nadler, Evan P.; Wong, Catarina T.; Zhou, Xin; Zhang, Xiao Ru; Ford, Henri.
In: Journal of Surgical Research, Vol. 106, No. 1, 01.01.2002, p. 7-14.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - NF-κB inhibition enhances peroxynitrite-induced enterocyte apoptosis
AU - Potoka, Douglas A.
AU - Upperman, Jeffrey S.
AU - Nadler, Evan P.
AU - Wong, Catarina T.
AU - Zhou, Xin
AU - Zhang, Xiao Ru
AU - Ford, Henri
PY - 2002/1/1
Y1 - 2002/1/1
N2 - Background. Sustained overproduction of nitric oxide and peroxynitrite (ONOO-) in conditions such as necrotizing enterocolitis and inflammatory bowel disease may promote gut barrier failure by inducing enterocyte apoptosis. NF-κB is upregulated in the gut during inflammation and, in addition to its proinflammatory effects, may upregulate protective or anti-apoptotic factors such as inhibitor of apoptosis proteins (IAPs). We have previously demonstrated that NF-κB inhibition increases cytokine-induced enterocyte apoptosis; however, the effect of NF-κB on ONOO--induced enterocyte apoptosis is unknown. Materials and methods. Rat intestinal epithelial cells (IEC-6) were transfected with the adenoviral vector AdIκB or AdlacZ. AdIκB contains a mutated form of IκB which functions as a superrepressor of NF-κB. Cells were then treated with 50 μM ONOO- or decomposed ONOO-. Apoptosis was then determined by flow cytometry with annexin V-FITC and propidium iodide staining. Caspase activation and IAP, Bcl-2, Bad, and Bax expression were examined using Western blot analysis, and NF-κB activation was determined via electrophoretic mobility shift assay (EMSA). Results. Inhibition of NF-κB with AdIκB significantly enhanced ONOO--induced apoptosis in IEC-6 cells. ONOO- treatment did not activate NF-κB in IEC-6 cells as determined by EMSA. There was no difference in IAP, Bcl-2, Bad, and Bax expression between nontransfected, AdlacZ-transfected, and AdIκB-transfected cells. Baseline procaspase 3 activation was increased in AdIκB-transfected cells. Conclusions. NF-κB inhibition enhances ONOO--induced enterocyte apoptosis, suggesting that NF-κB upregulates a protective factor. This protective factor does not appear to be an IAP or Bcl-2 family member and may be expressed constitutively, since ONOO- did not activate NF-κB over baseline levels of activation.
AB - Background. Sustained overproduction of nitric oxide and peroxynitrite (ONOO-) in conditions such as necrotizing enterocolitis and inflammatory bowel disease may promote gut barrier failure by inducing enterocyte apoptosis. NF-κB is upregulated in the gut during inflammation and, in addition to its proinflammatory effects, may upregulate protective or anti-apoptotic factors such as inhibitor of apoptosis proteins (IAPs). We have previously demonstrated that NF-κB inhibition increases cytokine-induced enterocyte apoptosis; however, the effect of NF-κB on ONOO--induced enterocyte apoptosis is unknown. Materials and methods. Rat intestinal epithelial cells (IEC-6) were transfected with the adenoviral vector AdIκB or AdlacZ. AdIκB contains a mutated form of IκB which functions as a superrepressor of NF-κB. Cells were then treated with 50 μM ONOO- or decomposed ONOO-. Apoptosis was then determined by flow cytometry with annexin V-FITC and propidium iodide staining. Caspase activation and IAP, Bcl-2, Bad, and Bax expression were examined using Western blot analysis, and NF-κB activation was determined via electrophoretic mobility shift assay (EMSA). Results. Inhibition of NF-κB with AdIκB significantly enhanced ONOO--induced apoptosis in IEC-6 cells. ONOO- treatment did not activate NF-κB in IEC-6 cells as determined by EMSA. There was no difference in IAP, Bcl-2, Bad, and Bax expression between nontransfected, AdlacZ-transfected, and AdIκB-transfected cells. Baseline procaspase 3 activation was increased in AdIκB-transfected cells. Conclusions. NF-κB inhibition enhances ONOO--induced enterocyte apoptosis, suggesting that NF-κB upregulates a protective factor. This protective factor does not appear to be an IAP or Bcl-2 family member and may be expressed constitutively, since ONOO- did not activate NF-κB over baseline levels of activation.
KW - Apoptosis
KW - Caspases
KW - Enterocyte
KW - Inhibitor of apoptosis proteins
KW - NF-κB
KW - Peroxynitrite
UR - http://www.scopus.com/inward/record.url?scp=0035983816&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0035983816&partnerID=8YFLogxK
U2 - 10.1006/jsre.2002.6423
DO - 10.1006/jsre.2002.6423
M3 - Article
VL - 106
SP - 7
EP - 14
JO - Journal of Surgical Research
JF - Journal of Surgical Research
SN - 0022-4804
IS - 1
ER -