PMID- 12138141 OWN - NLM STAT- MEDLINE DCOM- 20021227 LR - 20190607 IS - 1046-6673 (Print) IS - 1046-6673 (Linking) VI - 13 IP - 8 DP - 2002 Aug TI - Functional activation of heat shock factor and hypoxia-inducible factor in the kidney. PG - 2094-101 AB - Renal ischemia is the result of a complex series of events, including decreases in oxygen supply (hypoxia) and the availability of cellular energy (ATP depletion). In this study, the functional activation of two stress-responsive transcription factors, i.e., heat shock factor-1 (HSF-1) and hypoxia-inducible factor-1 (HIF-1), in the kidney was assessed. When rats were subjected to 45 min of renal ischemia, electrophoretic mobility shift assays of kidney nuclear extracts revealed rapid activation of both HIF-1 and HSF. Western blot analyses further demonstrated that this activation resulted in increased expression of the HSF and HIF-1 target genes heat shock protein-72 and heme oxygenase-1, respectively. Whether hypoxia or ATP depletion alone could produce similar activation patterns in vitro was then investigated. Renal epithelial LLC-PK(1) cells were subjected to either ATP depletion (0.1 microM antimycin A and glucose deprivation) or hypoxia (1% O(2)). After ATP depletion, HSF was rapidly activated (within 30 min), whereas HIF-1 was unaffected. In contrast, hypoxia led to the activation of HIF-1 but not HSF. Hypoxic activation of HIF-1 was observed within 30 min and persisted for 4 h, whereas no HSF activation was detected even with prolonged periods of hypoxia. HIF-1 was transcriptionally active in LLC-PK(1) cells, as demonstrated by luciferase reporter gene assays using the vascular endothelial growth factor promoter or a synthetic promoter construct containing three hypoxia-inducible elements. Interestingly, intracellular ATP levels were not affected by hypoxia but were significantly reduced by ATP depletion. These findings suggest that HIF-1 is activated specifically by decreased O(2) concentrations and not by reduced ATP levels alone. In contrast, HSF is activated primarily by metabolic stresses associated with ATP depletion and not by isolated O(2) deprivation. In vivo, the two transcription factors are simultaneously activated during renal ischemia, which might account for observed differences between in vivo and in vitro epithelial cell injury and repair. Selective modulation of either pathway might therefore be of potential interest for modification of the response of the kidney to ischemia, as well as the processes involved in recovery from ischemia. FAU - Eickelberg, Oliver AU - Eickelberg O AD - Departments of Pathology and Pediatrics, Yale University School of Medicine, New Haven, Connecticut, USA. oliver.eickelberg@innere.med.uni-giessen.de FAU - Seebach, Frank AU - Seebach F FAU - Riordan, Michael AU - Riordan M FAU - Thulin, Gunilla AU - Thulin G FAU - Mann, Andrea AU - Mann A FAU - Reidy, Kimberly H AU - Reidy KH FAU - Van Why, Scott K AU - Van Why SK FAU - Kashgarian, Michael AU - Kashgarian M FAU - Siegel, Norman AU - Siegel N LA - eng GR - DK38979/DK/NIDDK NIH HHS/United States GR - DK44336/DK/NIDDK NIH HHS/United States GR - HD32573/HD/NICHD NIH HHS/United States PT - Journal Article PT - Research Support, Non-U.S. Gov't PT - Research Support, U.S. Gov't, P.H.S. PL - United States TA - J Am Soc Nephrol JT - Journal of the American Society of Nephrology : JASN JID - 9013836 RN - 0 (DNA-Binding Proteins) RN - 0 (Heat Shock Transcription Factors) RN - 0 (Hif1a protein, rat) RN - 0 (Hypoxia-Inducible Factor 1) RN - 0 (Hypoxia-Inducible Factor 1, alpha Subunit) RN - 0 (Nuclear Proteins) RN - 0 (Transcription Factors) RN - 8L70Q75FXE (Adenosine Triphosphate) SB - IM MH - Adenosine Triphosphate/deficiency/metabolism MH - Animals MH - Cell Hypoxia/physiology MH - DNA-Binding Proteins/*physiology MH - Gene Expression/physiology MH - Heat Shock Transcription Factors MH - Hypoxia-Inducible Factor 1 MH - Hypoxia-Inducible Factor 1, alpha Subunit MH - Ischemia/metabolism MH - Kidney/*metabolism MH - LLC-PK1 Cells MH - Male MH - Nuclear Proteins/*physiology MH - Rats MH - Rats, Sprague-Dawley MH - Renal Circulation MH - Swine MH - *Transcription Factors MH - Transcriptional Activation/physiology EDAT- 2002/07/26 10:00 MHDA- 2002/12/28 04:00 CRDT- 2002/07/26 10:00 PHST- 2002/07/26 10:00 [pubmed] PHST- 2002/12/28 04:00 [medline] PHST- 2002/07/26 10:00 [entrez] AID - 10.1097/01.asn.0000022008.30175.5b [doi] PST - ppublish SO - J Am Soc Nephrol. 2002 Aug;13(8):2094-101. doi: 10.1097/01.asn.0000022008.30175.5b.