Oxygen-dependent regulation of mitochondrial respiration by hypoxia-inducible factor 1

2007 ◽  
Vol 405 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Gregg L. Semenza
Keyword(s):  
Mitochondrial Respiration ◽  
Mammalian Cells ◽  
Tricarboxylic Acid Cycle ◽  
Hypoxia Inducible Factor ◽  
Mitochondrial Respiratory Chain ◽  
Pyruvate Dehydrogenase Kinase ◽  
Complex Iii ◽  
Metabolic Adaptation ◽  
Acetyl Coa ◽  
Hypoxia Inducible Factor 1

The survival of metazoan organisms is dependent upon the utilization of O2 as a substrate for COX (cytochrome c oxidase), which constitutes Complex IV of the mitochondrial respiratory chain. Premature transfer of electrons, either at Complex I or at Complex III, results in the increased generation of ROS (reactive oxygen species). Recent studies have identified two critical adaptations that may function to prevent excessive ROS production in hypoxic cells. First, expression of PDK1 [PDH (pyruvate dehydrogenase) kinase 1] is induced. PDK1 phosphorylates and inactivates PDH, the mitochondrial enzyme that converts pyruvate into acetyl-CoA. In combination with the hypoxia-induced expression of LDHA (lactate dehydrogenase A), which converts pyruvate into lactate, PDK1 reduces the delivery of acetyl-CoA to the tricarboxylic acid cycle, thus reducing the levels of NADH and FADH2 delivered to the electron-transport chain. Secondly, the subunit composition of COX is altered in hypoxic cells by increased expression of the COX4-2 subunit, which optimizes COX activity under hypoxic conditions, and increased degradation of the COX4-1 subunit, which optimizes COX activity under aerobic conditions. Hypoxia-inducible factor 1 controls the metabolic adaptation of mammalian cells to hypoxia by activating transcription of the genes encoding PDK1, LDHA, COX4-2 and LON, a mitochondrial protease that is required for the degradation of COX4-1. COX subunit switching occurs in yeast, but by a completely different regulatory mechanism, suggesting that selection for O2-dependent homoeostatic regulation of mitochondrial respiration is ancient and likely to be shared by all eukaryotic organisms.

Emodin Decreases Hepatic Hypoxia-Inducible Factor-1α by Inhibiting its Biosynthesis

2016 ◽  
Vol 44 (05) ◽  
pp. 997-1008 ◽  
Author(s):  
Feifei Ma ◽  
Lijuan Hu ◽  
Ming Yu ◽  
Feng Wang
Keyword(s):  
Hepg2 Cells ◽  
Mammalian Cells ◽  
Hypoxia Inducible Factor ◽  
Hypoxia Inducible Factor 1 ◽  
Hepatic Cells ◽  
Diet Induced Obesity ◽  
Pathological Conditions ◽  
Therapeutic Value ◽  
Normal Stability

Hypoxia-inducible factor-1 (HIF-1) is an [Formula: see text] dimeric transcription factor. Because HIF-1[Formula: see text] is instable with oxygen, HIF-1 is scarce in normal mammalian cells. However, HIF-1[Formula: see text] is expressed in pathological conditions such as cancer and obesity. Inhibiting HIF-1[Formula: see text] may be of therapeutic value for these pathologies. Here, we investigated whether emodin, derived from the herb of Rheum palmatum L, which is also known as Chinese rhubarb, and is native to China, regulates HIF-1[Formula: see text] expression. Male C57BL/6 mice without or with diet-induced obesity were treated with emodin for two weeks, while control mice were treated with vehicle. HIF-1[Formula: see text] expression was determined by Western blot. We found that emodin inhibited obesity-induced HIF-1[Formula: see text] expression in liver and skeletal muscle but did not regulate HIF-1[Formula: see text] expression in the kidneys or in intra-abdominal fat. In vitro, emodin inhibited HIF-1[Formula: see text] expression in human HepG2 hepatic cells and Y1 adrenocortical cells. Further, we investigated the mechanisms of HIF-1[Formula: see text] expression in emodin-treated HepG2 cells. First, we found that HIF-1[Formula: see text] had normal stability in the presence of emodin. Thus, emodin did not decrease HIF-1[Formula: see text] by stimulating its degradation. Importantly, emodin decreased the activity of the signaling pathways that led to HIF-1[Formula: see text] biosynthesis. Interestingly, emodin increased HIF-1[Formula: see text] mRNA in HepG2 cells. This may be a result of feedback in response to the emodin-induced decrease in the protein of HIF-1[Formula: see text]. In conclusion, emodin decreases hepatic HIF-1[Formula: see text] by inhibiting its biosynthesis.

scholarly journals Hypoxia-inducible factor 1 levels vary exponentially over a physiologically relevant range of O2 tension

1996 ◽  
Vol 271 (4) ◽  
pp. C1172-C1180 ◽  
Author(s):  
B. H. Jiang ◽  
G. L. Semenza ◽  
C. Bauer ◽  
H. H. Marti
Keyword(s):  
Dna Binding ◽  
Transcriptional Activation ◽  
Mammalian Cells ◽  
Functional Characterization ◽  
Hypoxia Inducible Factor ◽  
Binding Activity ◽  
Maximal Response ◽  
Hypoxia Inducible Factor 1 ◽  
Dna Binding Activity

Hypoxia-inducible factor 1 (HIF-1) is a heterodimeric basic helix-loop-helix protein implicated in the transcriptional activation of genes encoding erythropoietin, glycolytic enzymes, and vascular endothelial growth factor in hypoxic mammalian cells. In this study, we have quantitated HIF-1 DNA-binding activity and protein levels of the HIF-1 alpha and HIF-1 beta subunits in human HeLa cells exposed to O2 concentrations ranging from 0 to 20% in the absence or presence of 1 mM KCN to inhibit oxidative phosphorylation and cellular O2 consumption. HIF-1 DNA-binding activity, HIF-1 alpha protein and HIF-1 beta protein each increased exponentially as cells were subjected to decreasing O2 concentrations, with a half maximal response between 1.5 and 2% O2 and a maximal response at 0.5% O2, both in the presence and absence of KCN. The HIF-1 response was greatest over O2 concentrations associated with ischemic/hypoxic events in vivo. These results provide evidence for the involvement of HIF-1 in O2 homeostasis and represent a functional characterization of the putative O2 sensor that initiates hypoxia signal transduction leading to HIF-1 expression.

scholarly journals Hypoxia-inducible Factor-1 Activation in Nonhypoxic Conditions: The Essential Role of Mitochondrial-derived Reactive Oxygen Species

2010 ◽  
Vol 21 (18) ◽  
pp. 3247-3257 ◽  
Author(s):  
David A. Patten ◽  
Véronique N. Lafleur ◽  
Geneviève A. Robitaille ◽  
Denise A. Chan ◽  
Amato J. Giaccia ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Nadph Oxidase ◽  
Hypoxia Inducible Factor ◽  
Reactive Oxygen ◽  
Protein Stabilization ◽  
Complex Iii ◽  
Oxygen Species ◽  
Ang Ii ◽  
Hypoxia Inducible Factor 1

Hypoxia-inducible factor-1 (HIF-1) is a key transcription factor for responses to low oxygen. Different nonhypoxic stimuli, including hormones and growth factors, are also important HIF-1 activators in the vasculature. Angiotensin II (Ang II), the main effecter hormone in the renin-angiotensin system, is a potent HIF-1 activator in vascular smooth muscle cells (VSMCs). HIF-1 activation by Ang II involves intricate mechanisms of HIF-1α transcription, translation, and protein stabilization. Additionally, the generation of reactive oxygen species (ROS) is essential for HIF-1 activation during Ang II treatment. However, the role of the different VSMC ROS generators in HIF-1 activation by Ang II remains unclear. This work aims at elucidating this question. Surprisingly, repression of NADPH oxidase-generated ROS, using Vas2870, a specific inhibitor or a p22phox siRNA had no significant effect on HIF-1 accumulation by Ang II. In contrast, repression of mitochondrial-generated ROS, by complex III inhibition, by Rieske Fe-S protein siRNA, or by the mitochondrial-targeted antioxidant SkQ1, strikingly blocked HIF-1 accumulation. Furthermore, inhibition of mitochondrial-generated ROS abolished HIF-1α protein stability, HIF-1–dependent transcription and VSMC migration by Ang II. A large number of studies implicate NADPH oxidase–generated ROS in Ang II–mediated signaling pathways in VSMCs. However, our work points to mitochondrial-generated ROS as essential intermediates for HIF-1 activation in nonhypoxic conditions.

Oligomycin inhibits HIF-1α expression in hypoxic tumor cells

2005 ◽  
Vol 288 (5) ◽  
pp. C1023-C1029 ◽  
Author(s):  
Yanqing Gong ◽  
Faton H. Agani
Keyword(s):  
Electron Transport ◽  
Hypoxia Inducible Factor ◽  
Mitochondrial Respiratory Chain ◽  
Inhibitory Effect ◽  
Protein Accumulation ◽  
Hypoxia Inducible Factor 1 ◽  
Transport Chain ◽  
Electron Transport Complexes ◽  
Respiratory Chain Inhibitors ◽  
Recent Attention

Hypoxia-inducible factor-1 (HIF-1) is a key regulator of cellular responses to reduced oxygen availability. The contribution of mitochondria in regulation of HIF-1α in hypoxic cells has received recent attention. We demonstrate that inhibition of electron transport complexes I, III, and IV diminished hypoxic HIF-1α accumulation in different tumor cell lines. Hypoxia-induced HIF-1α accumulation was not prevented by the antioxidants Trolox and N-acetyl-cysteine. Oligomycin, inhibitor of F0F1-ATPase, prevented hypoxia-induced HIF-1α protein accumulation and had no effect on HIF-1α induction by hypoxia-mimicking agents desferrioxamine or dimethyloxalylglycine. The inhibitory effect of mitochondrial respiratory chain inhibitors and oligomycin on hypoxic HIF-1α content was pronounced in cells exposed to hypoxia (1.5% O2) but decreased markedly when cells were exposed to severe oxygen deprivation (anoxia). Taken together, these results do not support the role for mitochondrial reactive oxygen species in HIF-1α regulation, but rather suggest that inhibition of electron transport chain and impaired oxygen consumption affect HIF-1α accumulation in hypoxic cells indirectly via effects on prolyl hydroxylase function.

scholarly journals The Qo site of the mitochondrial complex III is required for the transduction of hypoxic signaling via reactive oxygen species production

2007 ◽  
Vol 177 (6) ◽  
pp. 1029-1036 ◽  
Author(s):  
Eric L. Bell ◽  
Tatyana A. Klimova ◽  
James Eisenbart ◽  
Carlos T. Moraes ◽  
Michael P. Murphy ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Cytochrome B ◽  
Mammalian Cells ◽  
Hypoxia Inducible Factor ◽  
Reactive Oxygen ◽  
Complex Iii ◽  
Adaptation To Hypoxia ◽  
Ros Generation ◽  
Oxygen Species ◽  
Qo Site

Mammalian cells increase transcription of genes for adaptation to hypoxia through the stabilization of hypoxia-inducible factor 1α (HIF-1α) protein. How cells transduce hypoxic signals to stabilize the HIF-1α protein remains unresolved. We demonstrate that cells deficient in the complex III subunit cytochrome b, which are respiratory incompetent, increase ROS levels and stabilize the HIF-1α protein during hypoxia. RNA interference of the complex III subunit Rieske iron sulfur protein in the cytochrome b–null cells and treatment of wild-type cells with stigmatellin abolished reactive oxygen species (ROS) generation at the Qo site of complex III. These interventions maintained hydroxylation of HIF-1α protein and prevented stabilization of HIF-1α protein during hypoxia. Antioxidants maintained hydroxylation of HIF-1α protein and prevented stabilization of HIF-1α protein during hypoxia. Exogenous hydrogen peroxide under normoxia prevented hydroxylation of HIF-1α protein and stabilized HIF-1α protein. These results provide genetic and pharmacologic evidence that the Qo site of complex III is required for the transduction of hypoxic signal by releasing ROS to stabilize the HIF-1α protein.

Genes controlling the metabolic switch in hibernating mammals

2004 ◽  
Vol 32 (6) ◽  
pp. 1021-1024 ◽  
Author(s):  
M.T. Andrews
Keyword(s):  
Low Temperature ◽  
Pyruvate Dehydrogenase ◽  
Ground Squirrel ◽  
Mammalian Cells ◽  
Lipolytic Activity ◽  
Tricarboxylic Acid Cycle ◽  
Ground Squirrels ◽  
Pyruvate Dehydrogenase Kinase ◽  
Body Temperatures ◽  
Triacylglycerol Lipase

Hibernating mammals have the ability to decrease their metabolic rate and survive up to 6 months without food in an inactive state where body temperatures approach 0°C. In hibernating 13-lined ground squirrels (Spermophilus tridecemlineatus), oxygen consumption holds at 1/30 to 1/50 of the aroused condition and heart rates are as low as 3–10 beats/min, compared with 200–300 beats/min when the animal is active. This seasonal adaptation requires a metabolic shift away from the oxidation of carbohydrates and towards the combustion of stored fatty acids as the primary source of energy. A key element in this fuel switch is the differential expression of the gene encoding pyruvate dehydrogenase kinase isoenzyme 4. Pyruvate dehydrogenase kinase isoenzyme 4 inhibits pyruvate dehydrogenase and thus minimizes carbohydrate oxidation by preventing the flow of glycolytic products into the tricarboxylic acid cycle. Hibernators also exploit the low-temperature activity of PTL (pancreatic triacylglycerol lipase) in both heart and white adipose tissue. Lipolytic activity at body temperatures associated with hibernation was examined using recombinant ground squirrel and human PTL expressed in yeast. Enzymes from both humans and ground squirrel displayed high activity at temperatures as low as 0°C and showed Q10=1.2–1.5 over the temperature range 37–7°C. These studies indicate that low-temperature lipolysis is a general property of PTL and does not require protein modifications unique to mammalian cells and/or the hibernating state.

scholarly journals A Novel Malate Dehydrogenase 2 Inhibitor Suppresses Hypoxia-Inducible Factor-1 by Regulating Mitochondrial Respiration

PLoS ONE ◽  
2016 ◽  
Vol 11 (9) ◽  
pp. e0162568 ◽  
Author(s):  
Hyun Seung Ban ◽  
Xuezhen Xu ◽  
Kusik Jang ◽  
Inhyub Kim ◽  
Bo-Kyung Kim ◽  
...  
Keyword(s):  
Malate Dehydrogenase ◽  
Mitochondrial Respiration ◽  
Hypoxia Inducible Factor ◽  
Hypoxia Inducible Factor 1

scholarly journals Repression of Hypoxia-Inducible Factor-1 Contributes to Increased Mitochondrial Reactive Oxygen Species Production in Diabetes

2021 ◽  
Author(s):  
Xiaowei Zheng ◽  
Sampath Narayanan ◽  
Cheng Xu ◽  
Sofie Eliasson Angelstig ◽  
Jacob Grünler ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Hypoxia Inducible Factor ◽  
Reactive Oxygen ◽  
Pyruvate Dehydrogenase Kinase ◽  
Oxygen Species ◽  
Mitochondrial Reactive Oxygen Species ◽  
Glucose Levels ◽  
Hypoxia Inducible Factor 1 ◽  
Mitochondrial Ros ◽  
Functional Consequences

Background: Excessive production of mitochondrial reactive oxygen species (ROS) is a central mechanism for the development of diabetes complications. Recently, hypoxia has been identified to play an additional pathogenic role in diabetes. In this study, we hypothesized that ROS overproduction was secondary to the impaired responses to hypoxia due to the inhibition of hypoxia-inducible factor-1 (HIF-1) by hyperglycemia. Methods: The dynamic of ROS levels was analysed in the blood of healthy subjects and individuals with type 1 diabetes after exposure to hypoxia (ClinicalTrials.gov registration no. NCT02629406). The relation between HIF-1, glucose levels, ROS production and its functional consequences were analyzed in renal mIMCD-3 cells and in kidneys of mouse models of diabetes. Results: Exposure to hypoxia increased circulating ROS in subjects with diabetes, but not in subjects without diabetes. High glucose concentrations repressed HIF-1 both in hypoxic cells and in kidneys of animals with diabetes, through a HIF prolyl-hydroxylase (PHD) - dependent mechanism. The impaired HIF-1 signaling contributed to excess production of mitochondrial ROS through increased mitochondrial respiration that was mediated by Pyruvate dehydrogenase kinase 1 (PDK1) and was followed by functional consequences. The restoration of HIF-1 function attenuated ROS overproduction despite persistent hyperglycemia, and conferred protection against apoptosis and renal injury in diabetes. Conclusions: We conclude that the repression of HIF-1 plays a central role in mitochondrial ROS overproduction in diabetes and is a potential therapeutic target for diabetic complications. These findings are highly significant and timely since the first PHD inhibitor that can activate HIF-1 has been newly approved for clinical use.

Regulation of hypoxia-inducible factor is preserved in the absence of a functioning mitochondrial respiratory chain

Blood ◽  
2001 ◽  
Vol 98 (2) ◽  
pp. 296-302 ◽  
Author(s):  
Emma C. Vaux ◽  
Eric Metzen ◽  
Kay M. Yeates ◽  
Peter J. Ratcliffe
Keyword(s):  
Respiratory Chain ◽  
Glucose Transporter ◽  
Hypoxia Inducible Factor ◽  
Mitochondrial Respiratory Chain ◽  
Complex Iii ◽  
Wild Type ◽  
Transcriptional Responses ◽  
Glucose Transporter 1 ◽  
Helix Loop Helix ◽  
Essentially Normal

Hypoxia-inducible factor (HIF) mediates a large number of transcriptional responses to hypoxia and has an important role in processes that include angiogenesis and erythropoiesis. The HIF DNA binding complex consists of 2 basic-helix-loop-helix PAS proteins designated α and β subunits. Regulation occurs principally through the α subunits, which are stabilized and activated in hypoxia. Although substantial evidence implicates reactive oxygen species (ROS) in the regulatory process, the precise mechanisms remain unclear. Mitochondria are an important source of ROS, and in one model it has been proposed that hypoxia increases the generation of ROS at complex III in the mitochondrion and that this signal acts through a transduction pathway to stabilize HIF-1α and to activate HIF. To test this model the induction of the HIF-1α subunit and the HIF target gene, glucose-transporter-1, was examined in a variety of mutant cells that lacked mitochondrial DNA (ρ0) or had other genetic defects in mitochondrial respiration. HIF induction by hypoxia was essentially normal in all cells tested. Hydrogen peroxide production was measured by the luminol/peroxidase method and found to be reduced in ρ0 versus wild-type cells and reduced by hypoxia in both ρ0 and wild-type cells. Furthermore, concentrations of rotenone that maximally inhibited respiration did not affect HIF activation by hypoxia. These data do not support the model outlined above and indicate that a functional respiratory chain is not necessary for the regulation of HIF by oxygen.

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