Down-regulation of Hypoxia-inducible Factor-2 in PC12 Cells by Nerve Growth Factor Stimulation

Naranjo‐Suarez, Salvador; Castellanos, María C.; Álvarez-Tejado, Miguel; Vara, Alicia; Landázuri, Manuel O.; Peso, Luis del

doi:10.1074/jbc.m304079200

Cited by 30 publications

(23 citation statements)

References 33 publications

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“…Up-regulation of Their Gene Expression-It has been reported that hypoxia up-regulates EGLN1 and -3, but not EGLN2, mRNA in several cell types including HeLa cells (22), U2OS osteosarcoma cells (26), rat pheochromocytoma PC12 cells (27), and human cardiovascular cells (28). In addition to these cell lines, we have found that EGLN1 is up-regulated in HEK293, HepG2, and Jurkat cells and EGLN3 in HepG2 and Jurkat cells (Fig.…”

Section: Hypoxia Increases Egln1 and Egln3 Mrna Levels Bymentioning

confidence: 68%

“…In most of the cases reported, the induction of EGLN3 mRNA is much more prominent than that of EGLN1. Moreover, the increased mRNA levels correlate with increased EGLN activity (27). As a whole, these results suggest that EGLN1 and -3 can be targets of the pVHL/HIF pathway, but no evidence for this hypothesis has been reported.…”

mentioning

confidence: 70%

“…For each sample, duplicate determinations were made, and the gene copy number was normalized by the amount of ␤-actin. The primer pairs used in this study are reported elsewhere (27).…”

Section: Methodsmentioning

confidence: 99%

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The von Hippel Lindau/Hypoxia-inducible Factor (HIF) Pathway Regulates the Transcription of the HIF-Proline Hydroxylase Genes in Response to Low Oxygen

Peso

Castellanos

Temes

et al. 2003

Journal of Biological Chemistry

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171

107

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Most of the genes induced by hypoxia are regulated by a family of transcription factors termed hypoxia-inducible factors (HIF). Under normoxic conditions, HIF␣proteins are very unstable due to hydroxylation by a recently described family of proline hydroxylases termed EGL-Nine homologs (EGLN). Upon hydroxylation, HIF␣ is recognized by the product of the tumor suppressor vhl and targeted for proteosomal degradation. Since EGLNs require oxygen to catalize HIF hydroxylation, this reaction does not efficiently occur under low oxygen tension. Thus, under hypoxia, HIF␣ escapes from degradation and transcribes target genes. The mRNA levels of two of the three EGLNs described to date are induced by hypoxia, suggesting that they might be novel HIF target genes; however, no proof for this hypothesis has been reported. Here we show that the induction of EGLN1 and -3 by hypoxia is found in a wide range of cell types. The basal levels of EGLN3 are always well below those of EGLN1 and EGLN2, and its induction by hypoxia is larger than that found for EGLN1. The inhibitor of transcription, actinomycin D, prevents the increase of EGLN3 mRNA induced by hypoxia, indicating that it is due to enhanced gene expression. Interestingly, EGLN1 and EGLN3 mRNAs were also triggered by EGLN inhibitors, suggesting the involvement of HIF␣ in the control of its transcription. In agreement with this possibility, pVHL-deficient cell lines, which present high HIF activity under normoxia, also showed dramatically increased normoxic levels of EGLN3. Moreover, the overexpression of an oxygen-insensitive mutant form of HIF␣ resulted in increased normoxic levels of EGLN3 mRNA. Finally, hypoxic induction of EGLNs was not observed in cells lacking functional HIF␣.Mammalian cells are critically dependent on oxygen for survival; thus, it is not surprising that an evolutionarily conserved machinery able to sense oxygen levels is present in almost every cell type studied. The activity of a variety of signaling molecules has been found to be altered in response to changes in oxygen tension, including ion channels (1), kinases (2-7), and transcription factors (2, 8 -13). Among them, the most common and best understood response is the activation of a group of basic helix-loop-helix-Per/Aryl hydrocarbon receptor translocator/Sim domain transcription factors, called hypoxiainducible factors (HIF) 1 (14). In fact, HIF is responsible for the induction of the vast majority of genes up-regulated in response to decreased oxygen tension. HIF transcription factors are heterodimers of a constitutively expressed ␤ subunit (HIF-␤; also known as the aryl hydrocarbon receptor translocator) and an oxygen-regulated ␣ subunit (HIF-␣). Although there are three types of ␣ subunits, HIF-1␣, HIF-2␣ (also known as the endothelial Per/Aryl hydrocarbon receptor translocator/Sim domain), and HIF-3␣, encoded by different genes, it is currently accepted that they are regulated in a similar fashion by oxygen availability. The expression of HIF␤ and ␣ subunits genes, their mRNA stability, ...

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Section: Hypoxia Increases Egln1 and Egln3 Mrna Levels Bymentioning

confidence: 68%

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confidence: 70%

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The von Hippel Lindau/Hypoxia-inducible Factor (HIF) Pathway Regulates the Transcription of the HIF-Proline Hydroxylase Genes in Response to Low Oxygen

Peso

Castellanos

Temes

et al. 2003

Journal of Biological Chemistry

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171

107

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“…Several oxidation-sensitive transcription factors tested with a priori assumption, such as c-myc, hypoxia induced factor-2α (HIF-2α), and the peroxisome proliferator-activated receptor-γ (PPAR-γ)) (Haddad et al, 2000;De Nigris et al, 2001;Naranjo-Suarez et al, 2003) showed significant differential regulation, e.g., M4/G4: -17 (p = 0.002), 2.2 (p = 0.027), and -2.3 (p = 0.024) fold expression, respectively.…”

Section: Resultsmentioning

confidence: 99%

Effect of simulated microgravity on oxidation-sensitive gene expression in PC12 cells

Kwon

Sartor

Tomlinson

et al. 2006

Advances in Space Research

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Oxygen utilization by and oxygen dependence of cellular processes may be different in biological systems that are exposed to microgravity (micro-g). A baseline in which cellular changes in oxygen sensitive molecular processes occur during micro-g conditions would be important to pursue this question. The objective of this research is to analyze oxidation-sensitive gene expression in a model cell line [rat pheochromocytoma (PC12)] under simulated micro-g conditions. The PC12 cell line is well characterized in its response to oxygen, and is widely recognized as a sensitive model for studying the responses of oxygen-sensitive molecular and cellular processes. This study uses the rotating wall vessel bioreactor (RWV) designed at NASA to simulate micro-g. Gene expression in PC12 cells in response to micro-g was analyzed by DNA microarray technology. The microarray analysis of PC12 cells cultured for 4 days under simulated micro-g under standardized oxygen environment conditions revealed more than 100 genes whose expression levels were changed at least twofold (up-regulation of 65 genes and down-regulation of 39 genes) compared with those from cells in the unit gravity (unit-g) control. This study observed that genes involved in the oxidoreductase activity category were most significantly differentially expressed under micro-g conditions. Also, known oxidation-sensitive transcription factors such as hypoxia-inducible factor-2α, c-myc, and the peroxisome proliferator-activated receptor-γ were changed significantly. Our initial results from the gene expression microarray studies may provide a context in which to evaluate the effect of varying oxygen environments on the background of differential gene regulation of biological processes under variable gravity conditions.

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“…For each sample, duplicate determinations were carried out, and the gene copy number was normalized to the amount of ␤-actin. The primer pairs used in this study have been reported elsewhere (34).…”

Section: Methodsmentioning

confidence: 99%

Activation of HIF-prolyl Hydroxylases by R59949, an Inhibitor of the Diacylglycerol Kinase

Temes¹,

Martı́n-Puig²,

Acosta‐Iborra³

et al. 2005

Journal of Biological Chemistry

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Hypoxia-inducible factors (HIF) are heterodimeric (␣/␤) transcription factors that play a fundamental role in cellular adaptation to low oxygen tension. In the presence of oxygen, the HIF-␣ subunit becomes hydroxylated at specific prolyl residues by prolyl hydroxylases. This post-translational modification is recognized by the von Hippel-Lindau (VHL) protein, which targets HIF-␣ for degradation. In the absence of oxygen, HIF-␣ hydroxylation is compromised and this subunit is stabilized. We have previously shown that the hypoxia-induced accumulation of HIF-␣ protein is strongly impaired by the inhibitor of diacylglycerol kinase, R59949. Here, we have investigated the mechanisms through which this inhibitor exerts its effect. We found that R59949 inhibits the accumulation of HIF-1/2␣ protein without affecting the expression of their mRNAs. We also determined that R59949 could only block the accumulation of HIF-␣ in the presence of VHL protein. In agreement with this, the binding of VHL to endogenous HIF-␣ was significantly enhanced after R59949 treatment, even under hypoxic conditions. In addition, we found that R59949 could stimulate prolyl hydroxylase both at 21% O 2 as well as at 1% O 2 . Taken together, these results reveal that R59949 is an activator of HIF prolyl hydroxylases. This is of particular interest when we consider that, to date, mainly inhibitors of these enzymes have been described.

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Down-regulation of Hypoxia-inducible Factor-2 in PC12 Cells by Nerve Growth Factor Stimulation

Cited by 30 publications

References 33 publications

The von Hippel Lindau/Hypoxia-inducible Factor (HIF) Pathway Regulates the Transcription of the HIF-Proline Hydroxylase Genes in Response to Low Oxygen

The von Hippel Lindau/Hypoxia-inducible Factor (HIF) Pathway Regulates the Transcription of the HIF-Proline Hydroxylase Genes in Response to Low Oxygen

Effect of simulated microgravity on oxidation-sensitive gene expression in PC12 cells

Activation of HIF-prolyl Hydroxylases by R59949, an Inhibitor of the Diacylglycerol Kinase

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