Open AccessExpression and Function of Ets-1 during Experimental Acute Renal Failure in Rats
Author(s) -
Hiroyuki Tanaka,
Yoshio Terada,
Takahiko Kobayashi,
Tomokazu Okado,
Seiji Inoshita,
Michio Kuwahara,
Arun Seth,
Yasufumi Sato,
Sei Sasaki
Publication year - 2004
Publication title -
journal of the american society of nephrology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.451
H-Index - 279
eISSN - 1533-3450
pISSN - 1046-6673
DOI - 10.1097/01.asn.0000145459.54236.d3
Subject(s) - cyclin d1 , transcription factor , biology , cell cycle , proliferating cell nuclear antigen , messenger rna , ets transcription factor family , kidney , hypoxia inducible factors , microbiology and biotechnology , cell growth , endocrinology , cell , gene , biochemistry
The Ets family of transcription factors is defined by a conserved DNA-binding Ets domain that forms a winged helix-turn-helix structure motif. The Ets family is involved in a diverse array of biologic functions, including cellular growth, migration, and differentiation. The hypothesis in this study was that Ets-1 is re-expressed during regeneration after acute renal failure (ARF) and plays a key role in the transcriptional regulation of cyclin D1 and the cell cycle progression in renal tubular cells. For clarifying the significance of Ets-1 in ARF, a rat ARF model in vivo and LLC-PK1 cells as an in vitro model were used. After the left rat renal artery was clamped for 1 h, the whole kidney homogenate was examined and total RNA was extracted at 6, 12, 24, 48, and 72 h after reperfusion by Western blot analysis and real-time reverse transcription-PCR. Ets-1 mRNA and protein expression were strongly increased at 6 to 24 h after the ischemia, respectively. The expression of hypoxia-inducible factor-1alpha was increased dramatically as early as 6 h after ischemia-reperfusion and decreased at 48 and 72 h after ischemia-reperfusion. In the immunohistologic examination, Ets-1 was expressed in the proximal tubules and coexpressed with proliferating cell nuclear antigen (PCNA). Furthermore, overexpression of Ets-1 promoted the cell cycle and increased the promoter activity and protein expression of cyclin D1 in LLC-PK1 cells. Ets-1 promoter activity increased between 3 and 6 h in hypoxia, and hypoxia also induced changes in the Ets-1 protein level in LLC-PK1 cells. The Ets-1 induction by hypoxia was abolished by the transfection of dominant-negative hypoxia-inducible factor-1alpha. A gel shift assay demonstrated that Ets-1 binds to the ets-1 binding site of the cyclin D1 promoter in the ischemia-reperfusion condition. Overexpression of Ets-1 did not significantly change the caspase 3 activity or the value of cell death ELISA in LLC-PK1 cells. Taken together, these data suggest that Ets-1 plays a key role in the cell-cycle progression of renal tubules in ARF. The Ets-1 pathway may regulate the transcription of cyclin D1 and control the regeneration of renal tubules in ARF.