Heat shock induces IkappaB-alpha and prevents stress-induced endothelial cell apoptosis.
OBJECTIVE
To determine whether prior heat shock would attenuate endothelial cell apoptosis and whether any effect of preemptive heat shock is mediated through a nuclear factor kappa B and inhibitor kappa B alpha mechanism.


METHODS
A randomized, controlled in vitro study.


METHODS
A laboratory in a large, academic medical center.


METHODS
Cultured primary porcine endothelial cells were treated with increasing doses of sodium arsenite (40-160 micromol/L), after which the interval until subsequent apoptotic (lipopolysaccharide-arsenite) challenge was varied (4-16 hours). The degree of cell death and apoptosis were determined using neutral red uptake and staining with annexin V and propidium iodide, respectively. Inducible heat shock protein 70 and inhibitor kappa B alpha levels in treated cells were determined by Western blot analysis. Lipopolysaccharide-induced nuclear factor kappa B activity was assessed using an electrophoretic mobility shift assay.


RESULTS
Prior arsenite treatment decreased cell death by apoptosis in a time- and dose-dependent manner. Specifically, a higher sodium arsenite concentration and shorter intervals afforded better protection (P=.01, 160 micromol/L at 4 hours). Protection against apoptosis correlated with increased heat shock protein 70 and inhibitor kappa B alpha levels and decreased nuclear factor kappa B binding activity.


CONCLUSIONS
Arsenite, an inducer of the heat shock response, decreased stress-induced endothelial cell apoptosis. The mechanism of this protection may include decreased nuclear factor kappa B activity or increased inducible heat shock protein 70 levels. Heat shock protein 70 may serve as a molecular marker to determine not only the phenotypic state of the cell but also the durability of protection afforded by heat shock. These data support the hypothesis that stress-induced changes in transcription factor activity and protein expression can regulate the induction of apoptosis.
DeMeester
S L
SL
Department of Surgery, Washington University School of Medicine, St Louis, Mo, USA.
Buchman
T G
TG
Qiu
Y
Y
Jacob
A K
AK
Dunnigan
K
K
Hotchkiss
R S
RS
Karl
I
I
Cobb
J P
JP
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D018053:Arsenites / Q000494:pharmacology; D015153:Blotting, Western; D004586:Electrophoresis; D004727:Endothelium / Q000166:cytology; D018840:HSP70 Heat-Shock Proteins / Q000502:physiology*; D018869:Heat-Shock Response; D016328:NF-kappa B / Q000502:physiology*; D017670:Sodium Compounds / Q000494:pharmacology; D013439:Sulfhydryl Reagents; D013552:Swine
D018053:Arsenites; D018840:HSP70 Heat-Shock Proteins; D016328:NF-kappa B; D017670:Sodium Compounds; D013439:Sulfhydryl Reagents; C017947:sodium arsenite