Abstract |
Hypothermia (HT) has been associated with both beneficial and detrimental consequences in various pathophysiological states. While HT is generally thought to have anti-inflammatory and cytoprotective effects, we have previously shown that moderate in vitro HT prolongs TNF-alpha production by LPS-stimulated mononuclear phagocytes, in part by prolonging TNF-alpha gene transcription and activation of the pleiotropic transcription factor NF-kappaB. In this study, we have further characterized the effect of moderate (32 degrees C) and marked (28 degrees C) HT in human monocytic THP-1 cells by showing that even short (2 h) exposure to HT followed by a return to normothermic conditions for 22 h resulted in augmented and prolonged production of TNF-alpha. Production of heat shock protein 72 and activation of heat shock factor 1 are not affected by HT in these studies, suggesting that the effect is not part of a generalized stress response. Using immunoblotting, we have shown that HT augments phosphorylation of IKK-beta and IKK-alpha (up to an 8-fold increase at 28 degrees C and a 3.6-fold increase at 32 degrees C vs. 37 degrees C). Furthermore, nuclear accumulation of NF-kappaB p65 was significantly prolonged in hypothermic cells (1.4- and 2.5-fold more nuclear p65 at 2 and 4 h at 28 vs. 37 degrees C). Reexpression of IkappaB-alpha, which contributes to the termination of NF-kappaB-dependent transcription, was delayed several hours in HT-exposed cells. Thus we have shown that clinically relevant HT alters both cytosolic and nuclear events responsible for NF-kappaB activation and deactivation. Enhanced NF-kappaB activation may contribute to the immunomodulatory effects of HT in various clinical settings.
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Authors | Karen D Fairchild, Ishwar S Singh, Heather C Carter, Lisa Hester, Jeffrey D Hasday |
Journal | American journal of physiology. Cell physiology
(Am J Physiol Cell Physiol)
Vol. 289
Issue 5
Pg. C1114-21
(Nov 2005)
ISSN: 0363-6143 [Print] United States |
PMID | 15972840
(Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S., Research Support, U.S. Gov't, P.H.S.)
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Chemical References |
- Lipopolysaccharides
- NF-kappa B
- Tumor Necrosis Factor-alpha
- Protein Serine-Threonine Kinases
- CHUK protein, human
- I-kappa B Kinase
- IKBKB protein, human
- IKBKE protein, human
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Topics |
- Cell Line
- Cell Nucleus
(metabolism)
- Dose-Response Relationship, Drug
- Gene Expression Regulation
(physiology)
- Humans
- Hypothermia, Induced
- I-kappa B Kinase
- Lipopolysaccharides
(immunology)
- Macrophage Activation
- Macrophages
(metabolism)
- NF-kappa B
(metabolism)
- Phosphorylation
- Protein Serine-Threonine Kinases
(metabolism)
- Time Factors
- Tumor Necrosis Factor-alpha
(biosynthesis)
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