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Dou M, Zhu D, Cui G, Li H, Di L, Wang L. Euphorbia helioscopia L. exhibits promising therapeutic effects on hemangioendothelioma and melanoma through angiogenesis inhibition. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2024; 129:155666. [PMID: 38678953 DOI: 10.1016/j.phymed.2024.155666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 04/05/2024] [Accepted: 04/20/2024] [Indexed: 05/01/2024]
Abstract
BACKGROUND Euphorbia helioscopia L (EHL), a widely used medicinal plant in traditional Chinese medicine, has shown promising effects on certain cancers. However, previous studies on EHL did not elucidate the underlying molecular mechanisms. Herein, for the first time, we present the strong therapeutic potential of EHL extracts on malignant hemangioendothelioma, a rare type of vascular tumor. PURPOSE To investigate the potential anti-tumor mechanism of extracts of EHL on hemangioendothelioma and melanoma. METHODS The dried stems and leaves of EHL were extracted with Ethyl Acetate and n-Butyl alcohol, yielding two crude extracts Ethyl Acetate fraction (EA) and n-Butyl alcohol fraction (Bu). EA and Bu were prepared to assess the potential mechanism by assays for cell proliferation, cell cycle, apoptosis, colony formation, tube formation, cellular metabolic activity, reactive oxygen species (ROS), N-Acetylcysteine (NAC) antagonism, RNA expression and western blot. To further confirm the anti-tumor effect of EHL in vivo, we established hemangioendothelioma and melanoma tumor-bearing mouse model using node mice and administered with EA and Bu, tracked alterations in tumor volume and survival rate. Furthermore, tissue samples were obtained for histological, protein, and genetic investigations. RESULTS We demonstrate that the injection of EA and Bu, significantly inhibits tumor growth and prolongs the lifespan of tumor-bearing mice. Bu treatment exhibited a remarkable 33 % healing effect on the primary hemangioendothelioma tumor, bringing the survival rate to a level comparable to that of healthy mice. Mechanically, both EA and Bu impair respiratory chain complexes, leading to mitochondrial dysfunction and accumulation of reactive oxygen species (ROS), resulting in DNA damage, cell apoptosis, and finally blocked angiogenesis. While EA demonstrates robust inhibitory effects on cancer cell growth and a broader impact on metabolism in vitro, the in vivo effect of Bu surpasses that of EA in terms of strength. EA and Bu also exhibit potent anti-tumor effects on a primary melanoma model by inhibiting angiogenesis. Importantly, when compared to other compounds used in the treatment of hemangioendothelioma, EA and Bu demonstrate more profound anti-tumor effects. CONCLUSION For the first time, our findings reveal that EHL extracts, especially the high polarity compounds, exhibit potent anti-tumor effects by targeting cellular metabolism, specifically through the inhibition of mitochondria-related metabolic activities. This leads to the accumulation of ROS and effectively suppresses abnormal angiogenesis.
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Affiliation(s)
- Man Dou
- Department of Biological Sciences, Faculty of Health Sciences, University of Macau, Macau, PR China; Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau, PR China; Ministry of Education Frontiers Science Center for Precision Oncology, University of Macau, PR China; Proteomics, Metabolomics and Drug development core facility, Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Dongliang Zhu
- Department of Biological Sciences, Faculty of Health Sciences, University of Macau, Macau, PR China; Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau, PR China; Ministry of Education Frontiers Science Center for Precision Oncology, University of Macau, PR China; Cancer Center, Faculty of Health Sciences, University of Macau, Macau, PR China
| | - Guozhen Cui
- Bioengineering department, Zunyi Medical college, Zhuhai, Guangdong, Province, PR China
| | - Haixia Li
- Guang' amen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China
| | - Lijun Di
- Department of Biological Sciences, Faculty of Health Sciences, University of Macau, Macau, PR China; Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau, PR China; Ministry of Education Frontiers Science Center for Precision Oncology, University of Macau, PR China; Cancer Center, Faculty of Health Sciences, University of Macau, Macau, PR China.
| | - Li Wang
- Department of Biological Sciences, Faculty of Health Sciences, University of Macau, Macau, PR China; Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau, PR China; Ministry of Education Frontiers Science Center for Precision Oncology, University of Macau, PR China; Proteomics, Metabolomics and Drug development core facility, Faculty of Health Sciences, University of Macau, Macau SAR, China.
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2
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Slawski J, Jaśkiewicz M, Barton A, Kozioł S, Collawn JF, Bartoszewski R. Regulation of the HIF switch in human endothelial and cancer cells. Eur J Cell Biol 2024; 103:151386. [PMID: 38262137 DOI: 10.1016/j.ejcb.2024.151386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 01/17/2024] [Accepted: 01/17/2024] [Indexed: 01/25/2024] Open
Abstract
Hypoxia-inducible factors (HIFs) are transcription factors that reprogram the transcriptome for cells to survive hypoxic insults and oxidative stress. They are important during embryonic development and reprogram the cells to utilize glycolysis when the oxygen levels are extremely low. This metabolic change facilitates normal cell survival as well as cancer cell survival. The key feature in survival is the transition between acute hypoxia and chronic hypoxia, and this is regulated by the transition between HIF-1 expression and HIF-2/HIF-3 expression. This transition is observed in many human cancers and endothelial cells and referred to as the HIF Switch. Here we discuss the mechanisms involved in the HIF Switch in human endothelial and cancer cells which include mRNA and protein levels of the alpha chains of the HIFs. A major continuing effort in this field is directed towards determining the differences between normal and tumor cell utilization of this important pathway, and how this could lead to potential therapeutic approaches.
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Affiliation(s)
- Jakub Slawski
- Department of Biophysics, Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland
| | - Maciej Jaśkiewicz
- International Research Agenda 3P, Medicine Laboratory, Medical University of Gdansk, Gdansk, Poland
| | - Anna Barton
- Department of Biophysics, Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland
| | - Sylwia Kozioł
- Department of Biophysics, Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland
| | - James F Collawn
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, USA
| | - Rafał Bartoszewski
- Department of Biophysics, Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland.
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3
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Burtscher J, Hohenauer E, Burtscher M, Millet GP, Egg M. Environmental and behavioral regulation of HIF-mitochondria crosstalk. Free Radic Biol Med 2023; 206:63-73. [PMID: 37385566 DOI: 10.1016/j.freeradbiomed.2023.06.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 06/05/2023] [Accepted: 06/19/2023] [Indexed: 07/01/2023]
Abstract
Reduced oxygen availability (hypoxia) can lead to cell and organ damage. Therefore, aerobic species depend on efficient mechanisms to counteract detrimental consequences of hypoxia. Hypoxia inducible factors (HIFs) and mitochondria are integral components of the cellular response to hypoxia and coordinate both distinct and highly intertwined adaptations. This leads to reduced dependence on oxygen, improved oxygen supply, maintained energy provision by metabolic remodeling and tapping into alternative pathways and increased resilience to hypoxic injuries. On one hand, many pathologies are associated with hypoxia and hypoxia can drive disease progression, for example in many cancer and neurological diseases. But on the other hand, controlled induction of hypoxia responses via HIFs and mitochondria can elicit profound health benefits and increase resilience. To tackle pathological hypoxia conditions or to apply health-promoting hypoxia exposures efficiently, cellular and systemic responses to hypoxia need to be well understood. Here we first summarize the well-established link between HIFs and mitochondria in orchestrating hypoxia-induced adaptations and then outline major environmental and behavioral modulators of their interaction that remain poorly understood.
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Affiliation(s)
- Johannes Burtscher
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland.
| | - Erich Hohenauer
- Rehabilitation and Exercise Science Laboratory (RES Lab), Department of Business Economics, Health and Social Care, University of Applied Sciences and Arts of Southern Switzerland, Landquart, Switzerland; International University of Applied Sciences THIM, Landquart, Switzerland; Department of Neurosciences and Movement Science, University of Fribourg, Fribourg, Switzerland; Department of Movement and Sport Sciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Martin Burtscher
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Grégoire P Millet
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Margit Egg
- Institute of Zoology, University of Innsbruck, Innsbruck, Austria
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4
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Targeting TRMT5 suppresses hepatocellular carcinoma progression via inhibiting the HIF-1α pathways. J Zhejiang Univ Sci B 2023; 24:50-63. [PMID: 36632750 PMCID: PMC9837375 DOI: 10.1631/jzus.b2200224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Accumulating evidence has confirmed the links between transfer RNA (tRNA) modifications and tumor progression. The present study is the first to explore the role of tRNA methyltransferase 5 (TRMT5), which catalyzes the m1G37 modification of mitochondrial tRNAs in hepatocellular carcinoma (HCC) progression. Here, based on bioinformatics and clinical analyses, we identified that TRMT5 expression was upregulated in HCC, which correlated with poor prognosis. Silencing TRMT5 attenuated HCC proliferation and metastasis both in vivo and in vitro, which may be partially explained by declined extracellular acidification rate (ECAR) and oxygen consumption rate (OCR). Mechanistically, we discovered that knockdown of TRMT5 inactivated the hypoxia-inducible factor-1 (HIF-1) signaling pathway by preventing HIF-1α stability through the enhancement of cellular oxygen content. Moreover, our data indicated that inhibition of TRMT5 sensitized HCC to doxorubicin by adjusting HIF-1α. In conclusion, our study revealed that targeting TRMT5 could inhibit HCC progression and increase the susceptibility of tumor cells to chemotherapy drugs. Thus, TRMT5 might be a carcinogenesis candidate gene that could serve as a potential target for HCC therapy.
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5
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Jaśkiewicz M, Moszyńska A, Króliczewski J, Cabaj A, Bartoszewska S, Charzyńska A, Gebert M, Dąbrowski M, Collawn JF, Bartoszewski R. The transition from HIF-1 to HIF-2 during prolonged hypoxia results from reactivation of PHDs and HIF1A mRNA instability. Cell Mol Biol Lett 2022; 27:109. [PMID: 36482296 PMCID: PMC9730601 DOI: 10.1186/s11658-022-00408-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 11/18/2022] [Indexed: 12/13/2022] Open
Abstract
The hypoxia-inducible factors (HIF) are transcription factors that activate the adaptive hypoxic response when oxygen levels are low. The HIF transcriptional program increases oxygen delivery by inducing angiogenesis and by promoting metabolic reprograming that favors glycolysis. The two major HIFs, HIF-1 and HIF-2, mediate this response during prolonged hypoxia in an overlapping and sequential fashion that is referred to as the HIF switch. Both HIF proteins consist of an unstable alpha chain and a stable beta chain. The instability of the alpha chains is mediated by prolyl hydroxylase (PHD) activity during normoxic conditions, which leads to ubiquitination and proteasomal degradation of the alpha chains. During normoxic conditions, very little HIF-1 or HIF-2 alpha-beta dimers are present because of PHD activity. During hypoxia, however, PHD activity is suppressed, and HIF dimers are stable. Here we demonstrate that HIF-1 expression is maximal after 4 h of hypoxia in primary endothelial cells and then is dramatically reduced by 8 h. In contrast, HIF-2 is maximal at 8 h and remains elevated up to 24 h. There are differences in the HIF-1 and HIF-2 transcriptional profiles, and therefore understanding how the transition between them occurs is important and not clearly understood. Here we demonstrate that the HIF-1 to HIF-2 transition during prolonged hypoxia is mediated by two mechanisms: (1) the HIF-1 driven increase in the glycolytic pathways that reactivates PHD activity and (2) the much less stable mRNA levels of HIF-1α (HIF1A) compared to HIF-2α (EPAS1) mRNA. We also demonstrate that the alpha mRNA levels directly correlate to the relative alpha protein levels, and therefore to the more stable HIF-2 expression during prolonged hypoxia.
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Affiliation(s)
- Maciej Jaśkiewicz
- grid.11451.300000 0001 0531 3426International Research Agenda 3P- Medicine Laboratory, Medical University of Gdansk, Gdansk, Poland
| | - Adrianna Moszyńska
- grid.11451.300000 0001 0531 3426Department of Biology and Pharmaceutical Botany, Medical University of Gdansk, Gdansk, Poland
| | - Jarosław Króliczewski
- grid.11451.300000 0001 0531 3426Department of Biology and Pharmaceutical Botany, Medical University of Gdansk, Gdansk, Poland
| | - Aleksandra Cabaj
- grid.419305.a0000 0001 1943 2944Laboratory of Bioinformatics, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, Warsaw, Poland
| | - Sylwia Bartoszewska
- grid.11451.300000 0001 0531 3426Department of Inorganic Chemistry, Medical University of Gdansk, Gdansk, Poland
| | - Agata Charzyńska
- grid.419305.a0000 0001 1943 2944Laboratory of Bioinformatics, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, Warsaw, Poland
| | - Magda Gebert
- grid.11451.300000 0001 0531 3426Department of Biology and Pharmaceutical Botany, Medical University of Gdansk, Gdansk, Poland
| | - Michał Dąbrowski
- grid.419305.a0000 0001 1943 2944Laboratory of Bioinformatics, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, Warsaw, Poland
| | - James F. Collawn
- grid.265892.20000000106344187Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, BirminghamBirmingham, AL 35233 USA
| | - Rafal Bartoszewski
- grid.8505.80000 0001 1010 5103Department of Biophysics, Faculty of Biotechnology, University of Wroclaw, F. Joliot-Curie 14a Street, 50-383 Wroclaw, Poland
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Targeting HIF-1α Function in Cancer through the Chaperone Action of NQO1: Implications of Genetic Diversity of NQO1. J Pers Med 2022; 12:jpm12050747. [PMID: 35629169 PMCID: PMC9146583 DOI: 10.3390/jpm12050747] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 04/25/2022] [Indexed: 02/04/2023] Open
Abstract
HIF-1α is a master regulator of oxygen homeostasis involved in different stages of cancer development. Thus, HIF-1α inhibition represents an interesting target for anti-cancer therapy. It was recently shown that the HIF-1α interaction with NQO1 inhibits proteasomal degradation of the former, thus suggesting that targeting the stability and/or function of NQO1 could lead to the destabilization of HIF-1α as a therapeutic approach. Since the molecular interactions of NQO1 with HIF-1α are beginning to be unraveled, in this review we discuss: (1) Structure–function relationships of HIF-1α; (2) our current knowledge on the intracellular functions and stability of NQO1; (3) the pharmacological modulation of NQO1 by small ligands regarding function and stability; (4) the potential effects of genetic variability of NQO1 in HIF-1α levels and function; (5) the molecular determinants of NQO1 as a chaperone of many different proteins including cancer-associated factors such as HIF-1α, p53 and p73α. This knowledge is then further discussed in the context of potentially targeting the intracellular stability of HIF-1α by acting on its chaperone, NQO1. This could result in novel anti-cancer therapies, always considering that the substantial genetic variability in NQO1 would likely result in different phenotypic responses among individuals.
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7
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Kan S, Duan M, Liu Y, Wang C, Xie J. Role of Mitochondria in Physiology of Chondrocytes and Diseases of Osteoarthritis and Rheumatoid Arthritis. Cartilage 2021; 13:1102S-1121S. [PMID: 34894777 PMCID: PMC8804744 DOI: 10.1177/19476035211063858] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
PURPOSE OF REVIEW Mitochondria are recognized to be one of the most important organelles in chondrocytes for their role in triphosphate (ATP) generation through aerobic phosphorylation. Mitochondria also participate in many intracellular processes involving modulating reactive oxygen species (ROS), responding to instantaneous hypoxia stress, regulating cytoplasmic transport of calcium ion, and directing mitophagy to maintain the homeostasis of individual chondrocytes. DESIGNS To summarize the specific role of mitochondria in chondrocytes, we screened related papers in PubMed database and the search strategy is ((mitochondria) AND (chondrocyte)) AND (English [Language]). The articles published in the past 5 years were included and 130 papers were studied. RESULTS In recent years, the integrity of mitochondrial structure has been regarded as a prerequisite for normal chondrocyte survival and defect in mitochondrial function has been found in cartilage-related diseases, such as osteoarthritis (OA) and rheumatoid arthritis (RA). However, the understanding of mitochondria in cartilage is still largely limited. The mechanism on how the changes in mitochondrial structure and function directly lead to the occurrence and development of cartilage-related diseases remains to be elusive. CONCLUSION This review aims to summarize the role of mitochondria in chondrocytes under the physiological and pathological changes from ATP generation, calcium homeostasis, redox regulation, mitophagy modulation, mitochondria biogenesis to immune response activation. The enhanced understanding of molecular mechanisms in mitochondria might offer some new cues for cartilage remodeling and pathological intervention.
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Affiliation(s)
- Shiyi Kan
- State Key Laboratory of Oral Diseases,
West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Mengmeng Duan
- State Key Laboratory of Oral Diseases,
West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yang Liu
- State Key Laboratory of Oral Diseases,
West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Chunli Wang
- “111” Project Laboratory of
Biomechanics and Tissue Repair, Bioengineering College, Chongqing University,
Chongqing, China
| | - Jing Xie
- State Key Laboratory of Oral Diseases,
West China Hospital of Stomatology, Sichuan University, Chengdu, China,“111” Project Laboratory of
Biomechanics and Tissue Repair, Bioengineering College, Chongqing University,
Chongqing, China,Lab of Bone & Joint Disease, State
Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan
University, Chengdu, China,Jing Xie, Lab of Bone & Joint Disease,
State Key Laboratory of Oral Diseases, West China Hospital of Stomatology,
Sichuan University, Chengdu 610064, Sichuan, China.
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Kumar A, Vaish M, Karuppagounder SS, Gazaryan I, Cave JW, Starkov AA, Anderson ET, Zhang S, Pinto JT, Rountree AM, Wang W, Sweet IR, Ratan RR. HIF1α stabilization in hypoxia is not oxidant-initiated. eLife 2021; 10:72873. [PMID: 34596045 PMCID: PMC8530508 DOI: 10.7554/elife.72873] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 09/19/2021] [Indexed: 01/08/2023] Open
Abstract
Hypoxic adaptation mediated by HIF transcription factors requires mitochondria, which have been implicated in regulating HIF1α stability in hypoxia by distinct models that involve consuming oxygen or alternatively converting oxygen into the second messenger peroxide. Here, we use a ratiometric, peroxide reporter, HyPer to evaluate the role of peroxide in regulating HIF1α stability. We show that antioxidant enzymes are neither homeostatically induced nor are peroxide levels increased in hypoxia. Additionally, forced expression of diverse antioxidant enzymes, all of which diminish peroxide, had disparate effects on HIF1α protein stability. Moreover, decrease in lipid peroxides by glutathione peroxidase-4 or superoxide by mitochondrial SOD, failed to influence HIF1α protein stability. These data show that mitochondrial, cytosolic or lipid ROS were not necessary for HIF1α stability, and favor a model where mitochondria contribute to hypoxic adaptation as oxygen consumers.
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Affiliation(s)
- Amit Kumar
- Burke Neurological Institute, White Plains, New York, United States.,Brain and Mind Research Institute, Weill Medical College of Cornell University, New York, United States.,Department of Neurology, Weill Medical College of Cornell University, New York, United States
| | - Manisha Vaish
- Burke Neurological Institute, White Plains, New York, United States.,Pandemic Response Lab, New York, United States
| | - Saravanan S Karuppagounder
- Burke Neurological Institute, White Plains, New York, United States.,Brain and Mind Research Institute, Weill Medical College of Cornell University, New York, United States.,Department of Neurology, Weill Medical College of Cornell University, New York, United States
| | - Irina Gazaryan
- Department of Anatomy and Cell Biology, New York Medical College, New York, United States
| | - John W Cave
- Burke Neurological Institute, White Plains, New York, United States.,Brain and Mind Research Institute, Weill Medical College of Cornell University, New York, United States.,Department of Neurology, Weill Medical College of Cornell University, New York, United States
| | - Anatoly A Starkov
- Brain and Mind Research Institute, Weill Medical College of Cornell University, New York, United States.,Department of Neurology, Weill Medical College of Cornell University, New York, United States
| | | | - Sheng Zhang
- Institute for Biotechnology, Cornell University, Ithaca, United States
| | - John T Pinto
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, United States
| | - Austin M Rountree
- Department of Medicine, University of Washington, Seattle, United States
| | - Wang Wang
- Department of Pain and Anesthesiology, University of Washington, Seattle, United States
| | - Ian R Sweet
- Department of Medicine, University of Washington, Seattle, United States
| | - Rajiv R Ratan
- Burke Neurological Institute, White Plains, New York, United States.,Brain and Mind Research Institute, Weill Medical College of Cornell University, New York, United States.,Department of Neurology, Weill Medical College of Cornell University, New York, United States
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9
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DeFrates KG, Franco D, Heber-Katz E, Messersmith PB. Unlocking mammalian regeneration through hypoxia inducible factor one alpha signaling. Biomaterials 2021; 269:120646. [PMID: 33493769 PMCID: PMC8279430 DOI: 10.1016/j.biomaterials.2020.120646] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 12/19/2020] [Accepted: 12/29/2020] [Indexed: 02/08/2023]
Abstract
Historically, the field of regenerative medicine has aimed to heal damaged tissue through the use of biomaterials scaffolds or delivery of foreign progenitor cells. Despite 30 years of research, however, translation and commercialization of these techniques has been limited. To enable mammalian regeneration, a more practical approach may instead be to develop therapies that evoke endogenous processes reminiscent of those seen in innate regenerators. Recently, investigations into tadpole tail regrowth, zebrafish limb restoration, and the super-healing Murphy Roths Large (MRL) mouse strain, have identified ancient oxygen-sensing pathways as a possible target to achieve this goal. Specifically, upregulation of the transcription factor, hypoxia-inducible factor one alpha (HIF-1α) has been shown to modulate cell metabolism and plasticity, as well as inflammation and tissue remodeling, possibly priming injuries for regeneration. Since HIF-1α signaling is conserved across species, environmental or pharmacological manipulation of oxygen-dependent pathways may elicit a regenerative response in non-healing mammals. In this review, we will explore the emerging role of HIF-1α in mammalian healing and regeneration, as well as attempts to modulate protein stability through hyperbaric oxygen treatment, intermittent hypoxia therapy, and pharmacological targeting. We believe that these therapies could breathe new life into the field of regenerative medicine.
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Affiliation(s)
- Kelsey G DeFrates
- Department of Bioengineering and Materials Science and Engineering, University of California, Berkeley, CA, USA.
| | - Daniela Franco
- Department of Bioengineering and Materials Science and Engineering, University of California, Berkeley, CA, USA.
| | - Ellen Heber-Katz
- Laboratory of Regenerative Medicine, Lankenau Institute for Medical Research, Wynnewood, PA, USA.
| | - Phillip B Messersmith
- Department of Bioengineering and Materials Science and Engineering, University of California, Berkeley, CA, USA; Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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10
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Holzer T, Probst K, Etich J, Auler M, Georgieva VS, Bluhm B, Frie C, Heilig J, Niehoff A, Nüchel J, Plomann M, Seeger JM, Kashkar H, Baris OR, Wiesner RJ, Brachvogel B. Respiratory chain inactivation links cartilage-mediated growth retardation to mitochondrial diseases. J Cell Biol 2019; 218:1853-1870. [PMID: 31085560 PMCID: PMC6548139 DOI: 10.1083/jcb.201809056] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 01/12/2019] [Accepted: 04/12/2019] [Indexed: 12/17/2022] Open
Abstract
Children with mitochondrial diseases often present with slow growth and short stature, but the underlying mechanism remains unclear. In this study, Holzer et al. provide in vivo evidence that mitochondrial respiratory chain dysfunction induces cartilage degeneration coincident with altered metabolism, impaired extracellular matrix formation, and cell death at the cartilage–bone junction. In childhood, skeletal growth is driven by transient expansion of cartilage in the growth plate. The common belief is that energy production in this hypoxic tissue mainly relies on anaerobic glycolysis and not on mitochondrial respiratory chain (RC) activity. However, children with mitochondrial diseases causing RC dysfunction often present with short stature, which indicates that RC activity may be essential for cartilage-mediated skeletal growth. To elucidate the role of the mitochondrial RC in cartilage growth and pathology, we generated mice with impaired RC function in cartilage. These mice develop normally until birth, but their later growth is retarded. A detailed molecular analysis revealed that metabolic signaling and extracellular matrix formation is disturbed and induces cell death at the cartilage–bone junction to cause a chondrodysplasia-like phenotype. Hence, the results demonstrate the overall importance of the metabolic switch from fetal glycolysis to postnatal RC activation in growth plate cartilage and explain why RC dysfunction can cause short stature in children with mitochondrial diseases.
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Affiliation(s)
- Tatjana Holzer
- Department of Pediatrics and Adolescent Medicine, Experimental Neonatology, Faculty of Medicine, University of Cologne, Cologne, Germany.,Center for Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Kristina Probst
- Department of Pediatrics and Adolescent Medicine, Experimental Neonatology, Faculty of Medicine, University of Cologne, Cologne, Germany.,Center for Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Julia Etich
- Department of Pediatrics and Adolescent Medicine, Experimental Neonatology, Faculty of Medicine, University of Cologne, Cologne, Germany.,Center for Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Markus Auler
- Department of Pediatrics and Adolescent Medicine, Experimental Neonatology, Faculty of Medicine, University of Cologne, Cologne, Germany.,Center for Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Veronika S Georgieva
- Department of Pediatrics and Adolescent Medicine, Experimental Neonatology, Faculty of Medicine, University of Cologne, Cologne, Germany.,Center for Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Björn Bluhm
- Department of Pediatrics and Adolescent Medicine, Experimental Neonatology, Faculty of Medicine, University of Cologne, Cologne, Germany.,Center for Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Christian Frie
- Department of Pediatrics and Adolescent Medicine, Experimental Neonatology, Faculty of Medicine, University of Cologne, Cologne, Germany.,Center for Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Juliane Heilig
- Institute of Biomechanics and Orthopedics, German Sport University Cologne, Cologne, Germany.,Cologne Center for Musculoskeletal Biomechanics, University of Cologne, Cologne, Germany
| | - Anja Niehoff
- Institute of Biomechanics and Orthopedics, German Sport University Cologne, Cologne, Germany.,Cologne Center for Musculoskeletal Biomechanics, University of Cologne, Cologne, Germany
| | - Julian Nüchel
- Center for Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Markus Plomann
- Center for Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Jens M Seeger
- Institute for Medical Microbiology, Immunology, and Hygiene, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Hamid Kashkar
- Institute for Medical Microbiology, Immunology, and Hygiene, Faculty of Medicine, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany.,Center of Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Olivier R Baris
- Center for Physiology and Pathophysiology, Institute of Vegetative Physiology, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Rudolf J Wiesner
- Center for Physiology and Pathophysiology, Institute of Vegetative Physiology, Faculty of Medicine, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany.,Center of Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Bent Brachvogel
- Department of Pediatrics and Adolescent Medicine, Experimental Neonatology, Faculty of Medicine, University of Cologne, Cologne, Germany .,Center for Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany
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11
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Chen R, Lai UH, Zhu L, Singh A, Ahmed M, Forsyth NR. Reactive Oxygen Species Formation in the Brain at Different Oxygen Levels: The Role of Hypoxia Inducible Factors. Front Cell Dev Biol 2018; 6:132. [PMID: 30364203 PMCID: PMC6192379 DOI: 10.3389/fcell.2018.00132] [Citation(s) in RCA: 161] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 09/21/2018] [Indexed: 12/11/2022] Open
Abstract
Hypoxia inducible factor (HIF) is the master oxygen sensor within cells and is central to the regulation of cell responses to varying oxygen levels. HIF activation during hypoxia ensures optimum ATP production and cell integrity, and is associated both directly and indirectly with reactive oxygen species (ROS) formation. HIF activation can either reduce ROS formation by suppressing the function of mitochondrial tricarboxylic acid cycle (TCA cycle), or increase ROS formation via NADPH oxidase (NOX), a target gene of HIF pathway. ROS is an unavoidable consequence of aerobic metabolism. In normal conditions (i.e., physioxia), ROS is produced at minimal levels and acts as a signaling molecule subject to the dedicated balance between ROS production and scavenging. Changes in oxygen concentrations affect ROS formation. When ROS levels exceed defense mechanisms, ROS causes oxidative stress. Increased ROS levels can also be a contributing factor to HIF stabilization during hypoxia and reoxygenation. In this review, we systemically review HIF activation and ROS formation in the brain during hypoxia and hypoxia/reoxygenation. We will then explore the literature describing how changes in HIF levels might provide pharmacological targets for effective ischaemic stroke treatment. HIF accumulation in the brain via HIF prolyl hydroxylase (PHD) inhibition is proposed as an effective therapy for ischaemia stroke due to its antioxidation and anti-inflammatory properties in addition to HIF pro-survival signaling. PHD is a key regulator of HIF levels in cells. Pharmacological inhibition of PHD increases HIF levels in normoxia (i.e., at 20.9% O2 level). Preconditioning with HIF PHD inhibitors show a neuroprotective effect in both in vitro and in vivo ischaemia stroke models, but post-stroke treatment with PHD inhibitors remains debatable. HIF PHD inhibition during reperfusion can reduce ROS formation and activate a number of cellular survival pathways. Given agents targeting individual molecules in the ischaemic cascade (e.g., antioxidants) fail to be translated in the clinic setting, thus far, HIF pathway targeting and thereby impacting entire physiological networks is a promising drug target for reducing the adverse effects of ischaemic stroke.
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Affiliation(s)
- Ruoli Chen
- School of Pharmacy, Keele University, Staffordshire, United Kingdom.,Institute for Science and Technology in Medicine, Keele University, Staffordshire, United Kingdom
| | - U Hin Lai
- School of Pharmacy, Keele University, Staffordshire, United Kingdom
| | - Lingling Zhu
- Department of Brain Protection and Plasticity, Institute of Basic Medical Sciences, Beijing, China
| | - Ayesha Singh
- School of Pharmacy, Keele University, Staffordshire, United Kingdom.,Institute for Science and Technology in Medicine, Keele University, Staffordshire, United Kingdom
| | - Muhammad Ahmed
- Institute for Science and Technology in Medicine, Keele University, Staffordshire, United Kingdom.,College of Pharmacy, University of Mosul, Mosul, Iraq
| | - Nicholas R Forsyth
- Institute for Science and Technology in Medicine, Keele University, Staffordshire, United Kingdom
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12
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Iommarini L, Porcelli AM, Gasparre G, Kurelac I. Non-Canonical Mechanisms Regulating Hypoxia-Inducible Factor 1 Alpha in Cancer. Front Oncol 2017; 7:286. [PMID: 29230384 PMCID: PMC5711814 DOI: 10.3389/fonc.2017.00286] [Citation(s) in RCA: 153] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 11/13/2017] [Indexed: 12/21/2022] Open
Abstract
Hypoxia-inducible factor 1 alpha (HIF-1α) orchestrates cellular adaptation to low oxygen and nutrient-deprived environment and drives progression to malignancy in human solid cancers. Its canonical regulation involves prolyl hydroxylases (PHDs), which in normoxia induce degradation, whereas in hypoxia allow stabilization of HIF-1α. However, in certain circumstances, HIF-1α regulation goes beyond the actual external oxygen levels and involves PHD-independent mechanisms. Here, we gather and discuss the evidence on the non-canonical HIF-1α regulation, focusing in particular on the consequences of mitochondrial respiratory complexes damage on stabilization of this pleiotropic transcription factor.
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Affiliation(s)
- Luisa Iommarini
- Dipartimento di Farmacia e Biotecnologie, Università di Bologna, Bologna, Italy
| | - Anna Maria Porcelli
- Dipartimento di Farmacia e Biotecnologie, Università di Bologna, Bologna, Italy
| | - Giuseppe Gasparre
- Dipartimento di Scienze Mediche e Chirurgiche, Università di Bologna, Bologna, Italy
| | - Ivana Kurelac
- Dipartimento di Scienze Mediche e Chirurgiche, Università di Bologna, Bologna, Italy
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13
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Bastian A, Matsuzaki S, Humphries KM, Pharaoh GA, Doshi A, Zaware N, Gangjee A, Ihnat MA. AG311, a small molecule inhibitor of complex I and hypoxia-induced HIF-1α stabilization. Cancer Lett 2016; 388:149-157. [PMID: 27939695 DOI: 10.1016/j.canlet.2016.11.040] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 11/29/2016] [Accepted: 11/30/2016] [Indexed: 12/21/2022]
Abstract
Cancer cells have a unique metabolic profile and mitochondria have been shown to play an important role in chemoresistance, tumor progression and metastases. This unique profile can be exploited by mitochondrial-targeted anticancer therapies. A small anticancer molecule, AG311, was previously shown to possess anticancer and antimetastatic activity in two cancer mouse models and to induce mitochondrial depolarization. This study defines the molecular effects of AG311 on the mitochondria to elucidate its observed efficacy. AG311 was found to competitively inhibit complex I activity at the ubiquinone-binding site. Complex I as a target for AG311 was further established by measuring oxygen consumption rate in tumor tissue isolated from AG311-treated mice. Cotreatment of cells and animals with AG311 and dichloroacetate, a pyruvate dehydrogenase kinase inhibitor that increases oxidative metabolism, resulted in synergistic cell kill and reduced tumor growth. The inhibition of mitochondrial oxygen consumption by AG311 was found to reduce HIF-1α stabilization by increasing oxygen tension in hypoxic conditions. Taken together, these results suggest that AG311 at least partially mediates its antitumor effect through inhibition of complex I, which could be exploited in its use as an anticancer agent.
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Affiliation(s)
- Anja Bastian
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, United States
| | - Satoshi Matsuzaki
- Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, United States
| | - Kenneth M Humphries
- Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, United States
| | - Gavin A Pharaoh
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, United States; Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, United States
| | - Arpit Doshi
- Division of Medicinal Chemistry, Graduate School of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, United States
| | - Nilesh Zaware
- Division of Medicinal Chemistry, Graduate School of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, United States
| | - Aleem Gangjee
- Division of Medicinal Chemistry, Graduate School of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, United States
| | - Michael A Ihnat
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, United States; Department of Pharmaceutical Sciences, University of Oklahoma College of Pharmacy, Oklahoma City, OK 73117, United States.
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14
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Prolyl hydroxylase domain enzymes and their role in cell signaling and cancer metabolism. Int J Biochem Cell Biol 2016; 80:71-80. [PMID: 27702652 DOI: 10.1016/j.biocel.2016.09.026] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 09/28/2016] [Accepted: 09/30/2016] [Indexed: 12/20/2022]
Abstract
The prolyl hydroxylase domain (PHD) enzymes regulate the stability of the hypoxia-inducible factor (HIF) in response to oxygen availability. During oxygen limitation, the inhibition of PHD permits the stabilization of HIF, allowing the cellular adaptation to hypoxia. This adaptation is especially important for solid tumors, which are often exposed to a hypoxic environment. However, and despite their original role as the oxygen sensors of the cell, PHD are currently known to display HIF-independent and hydroxylase-independent functions in the control of different cellular pathways, including mTOR pathway, NF-kB pathway, apoptosis and cellular metabolism. In this review, we summarize the recent advances in the regulation and functions of PHD in cancer signaling and cell metabolism.
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15
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Burén S, Gomes AL, Teijeiro A, Fawal MA, Yilmaz M, Tummala KS, Perez M, Rodriguez-Justo M, Campos-Olivas R, Megías D, Djouder N. Regulation of OGT by URI in Response to Glucose Confers c-MYC-Dependent Survival Mechanisms. Cancer Cell 2016; 30:290-307. [PMID: 27505673 DOI: 10.1016/j.ccell.2016.06.023] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 08/01/2015] [Accepted: 06/29/2016] [Indexed: 01/09/2023]
Abstract
Cancer cells can adapt and survive under low nutrient conditions, but underlying mechanisms remain poorly explored. We demonstrate here that glucose maintains a functional complex between the co-chaperone URI, PP1γ, and OGT, the enzyme catalyzing O-GlcNAcylation. Glucose deprivation induces the activation of PKA, which phosphorylates URI at Ser-371, resulting in PP1γ release and URI-mediated OGT inhibition. Low OGT activity reduces O-GlcNAcylation and promotes c-MYC degradation to maintain cell survival. In the presence of glucose, PP1γ-bound URI increases OGT and c-MYC levels. Accordingly, mice expressing non-phosphorylatable URI (S371A) in hepatocytes exhibit high OGT activity and c-MYC stabilization, accelerating liver tumorigenesis in agreement with c-MYC oncogenic functions. Our work uncovers that URI-regulated OGT confers c-MYC-dependent survival functions in response to glucose fluctuations.
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Affiliation(s)
- Stefan Burén
- Cancer Cell Biology Programme, Growth Factors, Nutrients and Cancer Group, Centro Nacional de Investigaciones Oncológicas, CNIO, Madrid 28029, Spain
| | - Ana L Gomes
- Cancer Cell Biology Programme, Growth Factors, Nutrients and Cancer Group, Centro Nacional de Investigaciones Oncológicas, CNIO, Madrid 28029, Spain
| | - Ana Teijeiro
- Cancer Cell Biology Programme, Growth Factors, Nutrients and Cancer Group, Centro Nacional de Investigaciones Oncológicas, CNIO, Madrid 28029, Spain
| | - Mohamad-Ali Fawal
- Cancer Cell Biology Programme, Growth Factors, Nutrients and Cancer Group, Centro Nacional de Investigaciones Oncológicas, CNIO, Madrid 28029, Spain
| | - Mahmut Yilmaz
- Cancer Cell Biology Programme, Growth Factors, Nutrients and Cancer Group, Centro Nacional de Investigaciones Oncológicas, CNIO, Madrid 28029, Spain
| | - Krishna S Tummala
- Cancer Cell Biology Programme, Growth Factors, Nutrients and Cancer Group, Centro Nacional de Investigaciones Oncológicas, CNIO, Madrid 28029, Spain
| | - Manuel Perez
- Biotechnology Programme, Confocal Microscopy Core Unit, Centro Nacional de Investigaciones Oncológicas, CNIO, Madrid 28029, Spain
| | - Manuel Rodriguez-Justo
- Department of Research Pathology, Cancer Institute, University College London, London WC1E 6JJ, UK
| | - Ramón Campos-Olivas
- Structural Biology and Biocomputing Programme, Spectroscopy and Nuclear Magnetic Resonance Unit, Centro Nacional de Investigaciones Oncológicas, CNIO, Madrid 28029, Spain
| | - Diego Megías
- Biotechnology Programme, Confocal Microscopy Core Unit, Centro Nacional de Investigaciones Oncológicas, CNIO, Madrid 28029, Spain
| | - Nabil Djouder
- Cancer Cell Biology Programme, Growth Factors, Nutrients and Cancer Group, Centro Nacional de Investigaciones Oncológicas, CNIO, Madrid 28029, Spain.
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16
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Wang D, Zhang J, Lu Y, Luo Q, Zhu L. Nuclear respiratory factor-1 (NRF-1) regulated hypoxia-inducible factor-1α (HIF-1α) under hypoxia in HEK293T. IUBMB Life 2016; 68:748-55. [PMID: 27491637 DOI: 10.1002/iub.1537] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Accepted: 07/05/2016] [Indexed: 12/26/2022]
Abstract
Hypoxia-inducible factor 1α (HIF-1α) is a master regulator of oxygen homeostasis. Under hypoxia, the active HIF1-α subunits are mainly regulated through increased protein stabilization. Little is known concerning HIF-1α transcriptional regulation. Nuclear respiratory factor 1 (NRF-1) is a DNA-binding transcription factor that regulates mitochondrial biogenesis. In this study, we showed that NRF-1was a repressor of HIF-1α. The cellular depletion of NRF-1 by siRNA targeting leads to increased HIF-1αtranscriptional activity. EMSA, ChIP and luciferase activity allowed the identification of two functional NRF-1 binding sites within HIF-1α promoter. This study therefore identifies NRF-1 as a novel regulator of HIF-1α. © 2016 IUBMB Life, 68(9):748-755, 2016.
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Affiliation(s)
- Dan Wang
- Department of Biochemistry, 9 Se Yuan Road, Nantong, Jiangsu, 226019, China
| | - Jie Zhang
- Department of Biochemistry, 9 Se Yuan Road, Nantong, Jiangsu, 226019, China
| | - Yapeng Lu
- Department of Biochemistry, 9 Se Yuan Road, Nantong, Jiangsu, 226019, China
| | - Qianqian Luo
- Department of Biochemistry, 9 Se Yuan Road, Nantong, Jiangsu, 226019, China
| | - Li Zhu
- Department of Biochemistry, 9 Se Yuan Road, Nantong, Jiangsu, 226019, China
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17
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Siegert I, Schödel J, Nairz M, Schatz V, Dettmer K, Dick C, Kalucka J, Franke K, Ehrenschwender M, Schley G, Beneke A, Sutter J, Moll M, Hellerbrand C, Wielockx B, Katschinski DM, Lang R, Galy B, Hentze MW, Koivunen P, Oefner PJ, Bogdan C, Weiss G, Willam C, Jantsch J. Ferritin-Mediated Iron Sequestration Stabilizes Hypoxia-Inducible Factor-1α upon LPS Activation in the Presence of Ample Oxygen. Cell Rep 2015; 13:2048-55. [PMID: 26628374 DOI: 10.1016/j.celrep.2015.11.005] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 09/29/2015] [Accepted: 11/01/2015] [Indexed: 12/11/2022] Open
Abstract
Both hypoxic and inflammatory conditions activate transcription factors such as hypoxia-inducible factor (HIF)-1α and nuclear factor (NF)-κB, which play a crucial role in adaptive responses to these challenges. In dendritic cells (DC), lipopolysaccharide (LPS)-induced HIF1α accumulation requires NF-κB signaling and promotes inflammatory DC function. The mechanisms that drive LPS-induced HIF1α accumulation under normoxia are unclear. Here, we demonstrate that LPS inhibits prolyl hydroxylase domain enzyme (PHD) activity and thereby blocks HIF1α degradation. Of note, LPS-induced PHD inhibition was neither due to cosubstrate depletion (oxygen or α-ketoglutarate) nor due to increased levels of reactive oxygen species, fumarate, and succinate. Instead, LPS inhibited PHD activity through NF-κB-mediated induction of the iron storage protein ferritin and subsequent decrease of intracellular available iron, a critical cofactor of PHD. Thus, hypoxia and LPS both induce HIF1α accumulation via PHD inhibition but deploy distinct molecular mechanisms (lack of cosubstrate oxygen versus deprivation of co-factor iron).
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Affiliation(s)
- Isabel Siegert
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen and Friedrich-Alexander Universität (FAU) Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Johannes Schödel
- Department of Nephrology and Hypertension, Universitätsklinikum Erlangen and Friedrich-Alexander Universität (FAU), 91054 Erlangen, Germany
| | - Manfred Nairz
- Department of Internal Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Valentin Schatz
- Institute of Clinical Microbiology and Hygiene, University Hospital of Regensburg and University of Regensburg, 93053 Regensburg, Germany
| | - Katja Dettmer
- Institute of Functional Genomics, University of Regensburg, 93053 Regensburg, Germany
| | - Christopher Dick
- Institute of Clinical Microbiology and Hygiene, University Hospital of Regensburg and University of Regensburg, 93053 Regensburg, Germany
| | - Joanna Kalucka
- Department of Nephrology and Hypertension, Universitätsklinikum Erlangen and Friedrich-Alexander Universität (FAU), 91054 Erlangen, Germany
| | - Kristin Franke
- Heisenberg Research Group, Department of Clinical Pathobiochemistry, Institute of Clinical Chemistry and Laboratory Medicine, University of Technology, 01307 Dresden, Germany
| | - Martin Ehrenschwender
- Institute of Clinical Microbiology and Hygiene, University Hospital of Regensburg and University of Regensburg, 93053 Regensburg, Germany
| | - Gunnar Schley
- Department of Nephrology and Hypertension, Universitätsklinikum Erlangen and Friedrich-Alexander Universität (FAU), 91054 Erlangen, Germany
| | - Angelika Beneke
- Institute of Cardiovascular Physiology, University Medical Center, Georg-August-University Göttingen, 37073 Göttingen, Germany
| | - Jörg Sutter
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander Universität (FAU) Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Matthias Moll
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander Universität (FAU) Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Claus Hellerbrand
- Department of Internal Medicine I, University of Regensburg, 93053 Regensburg, Germany
| | - Ben Wielockx
- Heisenberg Research Group, Department of Clinical Pathobiochemistry, Institute of Clinical Chemistry and Laboratory Medicine, University of Technology, 01307 Dresden, Germany
| | - Dörthe M Katschinski
- Institute of Cardiovascular Physiology, University Medical Center, Georg-August-University Göttingen, 37073 Göttingen, Germany
| | - Roland Lang
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen and Friedrich-Alexander Universität (FAU) Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Bruno Galy
- Division of Virus-Associated Carcinogenesis, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | | | - Peppi Koivunen
- Biocenter Oulu, Faculty of Biochemistry and Molecular Medicine, Oulu Center for Cell-Matrix Research, University of Oulu, 90014 Oulu, Finland
| | - Peter J Oefner
- Institute of Functional Genomics, University of Regensburg, 93053 Regensburg, Germany
| | - Christian Bogdan
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen and Friedrich-Alexander Universität (FAU) Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Günter Weiss
- Department of Internal Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Carsten Willam
- Department of Nephrology and Hypertension, Universitätsklinikum Erlangen and Friedrich-Alexander Universität (FAU), 91054 Erlangen, Germany
| | - Jonathan Jantsch
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen and Friedrich-Alexander Universität (FAU) Erlangen-Nürnberg, 91054 Erlangen, Germany; Institute of Clinical Microbiology and Hygiene, University Hospital of Regensburg and University of Regensburg, 93053 Regensburg, Germany.
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18
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Peroxiredoxin-5 targeted to the mitochondrial intermembrane space attenuates hypoxia-induced reactive oxygen species signalling. Biochem J 2015; 456:337-46. [PMID: 24044889 DOI: 10.1042/bj20130740] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The ability to adapt to acute and chronic hypoxia is critical for cellular survival. Two established functional responses to hypoxia include the regulation of gene transcription by HIF (hypoxia-inducible factor), and the constriction of pulmonary arteries in response to alveolar hypoxia. The mechanism of O2 sensing in these responses is not established, but some studies implicate hypoxia-induced mitochondrial ROS (reactive oxygen species) signalling. To further test this hypothesis, we expressed PRDX5 (peroxiredoxin-5), a H2O2 scavenger, in the IMS (mitochondrial intermembrane space), reasoning that the scavenging of ROS in that compartment should abrogate cellular responses triggered by the release of mitochondrial oxidants to the cytosol. Using adenoviral expression of IMS-PRDX5 (IMS-targeted PRDX5) in PASMCs (pulmonary artery smooth muscle cells) we show that IMS-PRDX5 inhibits hypoxia-induced oxidant signalling in the IMS and cytosol. It also inhibits HIF-1α stabilization and HIF activity in a dose-dependent manner without disrupting cellular oxygen consumption. IMS-PRDX5 expression also attenuates the increase in cytosolic [Ca(2+)] in PASMCs during hypoxia. These results extend previous work by demonstrating the importance of IMS-derived ROS signalling in both the HIF and lung vascular responses to hypoxia.
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19
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Gd-metallofullerenol nanomaterial as non-toxic breast cancer stem cell-specific inhibitor. Nat Commun 2015; 6:5988. [PMID: 25612916 PMCID: PMC4354030 DOI: 10.1038/ncomms6988] [Citation(s) in RCA: 125] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2013] [Accepted: 12/01/2014] [Indexed: 12/25/2022] Open
Abstract
The contemporary use of nanomedicines for cancer treatment has been largely limited to serving as carriers for existing therapeutic agents. Here, we provide definitive evidence that, the metallofullerenol nanomaterial Gd@C82(OH)22, while essentially not toxic to normal mammary epithelial cells, possesses intrinsic inhibitory activity against triple-negative breast cancer cells. Gd@C82(OH)22 blocks epithelial-to-mesenchymal transition with resultant efficient elimination of breast cancer stem cells (CSCs) resulting in abrogation of tumour initiation and metastasis. In normoxic conditions, Gd@C82(OH)22 mediates these effects by blocking TGF-β signalling. Moreover, under hypoxic conditions found in the tumour microenvironment, cellular uptake of Gd@C82(OH)22 is facilitated where it functions as a bi-potent inhibitor of HIF-1α and TGF-β activities, enhancing CSC elimination. These studies indicate that nanomaterials can be engineered to directly target CSCs. Thus, Gd-metallofullerenol is identified as a kind of non-toxic CSC specific inhibitors with significant therapeutic potential. A metallofullerenol nanomaterial, Gd@C82(OH)22, was shown to inhibit growth of several solid cancers in preclinical models and yet exhibit low toxicity. Herein the authors show that Gd@C82(OH)22 functions as an inhibitor of breast cancer stem cell function via blocking TGF-β and HIF-1α signalling, while sparing normal tissue.
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20
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Bishop T, Ratcliffe PJ. Signaling hypoxia by hypoxia-inducible factor protein hydroxylases: a historical overview and future perspectives. HYPOXIA 2014; 2:197-213. [PMID: 27774477 PMCID: PMC5045067 DOI: 10.2147/hp.s47598] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
By the early 1900s, the close matching of oxygen supply with demand was recognized to be a fundamental requirement for physiological function, and multiple adaptive responses to environment hypoxia had been described. Nevertheless, the widespread operation of mechanisms that directly sense and respond to levels of oxygen in animal cells was not appreciated for most of the twentieth century with investigators generally stressing the regulatory importance of metabolic products. Work over the last 25 years has overturned that paradigm. It has revealed the existence of a set of “oxygen-sensing” 2-oxoglutarate dependent dioxygenases that catalyze the hydroxylation of specific amino acid residues and thereby control the stability and activity of hypoxia-inducible factor. The hypoxia-inducible factor hydroxylase pathway regulates a massive transcriptional cascade that is operative in essentially all animal cells. It transduces a wide range of responses to hypoxia, extending well beyond the classical boundaries of hypoxia physiology. Here we review the discovery and elucidation of these pathways, and consider the opportunities and challenges that have been brought into focus by the findings, including new implications for the integrated physiology of hypoxia and therapeutic approaches to ischemic/hypoxic disease.
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Affiliation(s)
- Tammie Bishop
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
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21
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Ban JJ, Ruthenborg RJ, Cho KW, Kim JW. Regulation of obesity and insulin resistance by hypoxia-inducible factors. HYPOXIA 2014; 2:171-183. [PMID: 27774475 PMCID: PMC5045065 DOI: 10.2147/hp.s68771] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
In obesity, dysregulated metabolism and aberrant expansion of adipose tissue lead to the development of tissue hypoxia that plays an important role in contributing to obesity-associated metabolic disorders. Recent studies utilizing adipocyte-specific hypoxia-inducible factor-α (HIF-α) gain- or loss-of-function animal models highlight the pivotal involvement of hypoxic responses in the pathogenesis of obesity-associated inflammation and insulin resistance. HIF-1α, a master transcription factor of oxygen homeostasis, induces inflammation and insulin resistance in obesity, whereas its isoform, HIF-2α, exerts opposing functions in these obesity-associated metabolic phenotypes. In this review, recent evidence elucidating functional implications of adipocyte HIFs in obesity and, more importantly, how these regulate obesity-associated inflammation, fibrosis, and insulin resistance will be discussed. Further, we propose that modulation of HIF-1 could be a potential novel therapeutic strategy for antidiabetic treatment.
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Affiliation(s)
- Jae-Jun Ban
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, TX, USA
| | - Robin J Ruthenborg
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, TX, USA
| | - Kevin W Cho
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, TX, USA
| | - Jung-Whan Kim
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, TX, USA
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22
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Lee YS, Kim JW, Osborne O, Oh DY, Sasik R, Schenk S, Chen A, Chung H, Murphy A, Watkins SM, Quehenberger O, Johnson RS, Olefsky JM. Increased adipocyte O2 consumption triggers HIF-1α, causing inflammation and insulin resistance in obesity. Cell 2014; 157:1339-1352. [PMID: 24906151 PMCID: PMC4114226 DOI: 10.1016/j.cell.2014.05.012] [Citation(s) in RCA: 393] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 01/30/2014] [Accepted: 05/01/2014] [Indexed: 12/30/2022]
Abstract
Adipose tissue hypoxia and inflammation have been causally implicated in obesity-induced insulin resistance. Here, we report that, early in the course of high-fat diet (HFD) feeding and obesity, adipocyte respiration becomes uncoupled, leading to increased oxygen consumption and a state of relative adipocyte hypoxia. These events are sufficient to trigger HIF-1α induction, setting off the chronic adipose tissue inflammatory response characteristic of obesity. At the molecular level, these events involve saturated fatty acid stimulation of the adenine nucleotide translocase 2 (ANT2), an inner mitochondrial membrane protein, which leads to the uncoupled respiratory state. Genetic or pharmacologic inhibition of either ANT2 or HIF-1α can prevent or reverse these pathophysiologic events, restoring a state of insulin sensitivity and glucose tolerance. These results reveal the sequential series of events in obesity-induced inflammation and insulin resistance.
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Affiliation(s)
- Yun Sok Lee
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jung-Whan Kim
- Molecular Biology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Olivia Osborne
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, CA 92093, USA
| | - Da Young Oh
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, CA 92093, USA
| | - Roman Sasik
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, CA 92093, USA
| | - Simon Schenk
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, CA 92093, USA
| | - Ai Chen
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, CA 92093, USA
| | - Heekyung Chung
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, CA 92093, USA
| | - Anne Murphy
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | | | - Oswald Quehenberger
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, CA 92093, USA
| | - Randall S Johnson
- Molecular Biology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, 171 77, Sweden; Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK.
| | - Jerrold M Olefsky
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, CA 92093, USA.
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Selvaraju V, Parinandi NL, Adluri RS, Goldman JW, Hussain N, Sanchez JA, Maulik N. Molecular mechanisms of action and therapeutic uses of pharmacological inhibitors of HIF-prolyl 4-hydroxylases for treatment of ischemic diseases. Antioxid Redox Signal 2014; 20:2631-65. [PMID: 23992027 PMCID: PMC4026215 DOI: 10.1089/ars.2013.5186] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2013] [Revised: 08/06/2013] [Accepted: 09/01/2013] [Indexed: 12/13/2022]
Abstract
SIGNIFICANCE In this review, we have discussed the efficacy and effect of small molecules that act as prolyl hydroxylase domain inhibitors (PHDIs). The use of these compounds causes upregulation of the pro-angiogenic factors and hypoxia inducible factor-1α and -2α (HIF-1α and HIF-2α) to enhance angiogenic, glycolytic, erythropoietic, and anti-apoptotic pathways in the treatment of various ischemic diseases responsible for significant morbidity and mortality in humans. RECENT ADVANCES Sprouting of new blood vessels from the existing vasculature and surgical intervention, such as coronary bypass and stent insertion, have been shown to be effective in attenuating ischemia. However, the initial reentry of oxygen leads to the formation of reactive oxygen species that cause oxidative stress and result in ischemia/reperfusion (IR) injury. This apparent "oxygen paradox" must be resolved to combat IR injury. During hypoxia, decreased activity of PHDs initiates the accumulation and activation of HIF-1α, wherein the modulation of both PHD and HIF-1α appears as promising therapeutic targets for the pharmacological treatment of ischemic diseases. CRITICAL ISSUES Research on PHDs and HIFs has shown that these molecules can serve as therapeutic targets for ischemic diseases by modulating glycolysis, erythropoiesis, apoptosis, and angiogenesis. Efforts are underway to identify and synthesize safer small-molecule inhibitors of PHDs that can be administered in vivo as therapy against ischemic diseases. FUTURE DIRECTIONS This review presents a comprehensive and current account of the existing small-molecule PHDIs and their use in the treatment of ischemic diseases with a focus on the molecular mechanisms of therapeutic action in animal models.
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Affiliation(s)
- Vaithinathan Selvaraju
- Molecular Cardiology and Angiogenesis Laboratory, Department of Surgery, University of Connecticut Health Center, Farmington, Connecticut
| | - Narasimham L. Parinandi
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Dorothy M. Davis Heart & Lung Research Institute, The Ohio State University College of Medicine, Columbus, Ohio
| | - Ram Sudheer Adluri
- Molecular Cardiology and Angiogenesis Laboratory, Department of Surgery, University of Connecticut Health Center, Farmington, Connecticut
| | - Joshua W. Goldman
- Molecular Cardiology and Angiogenesis Laboratory, Department of Surgery, University of Connecticut Health Center, Farmington, Connecticut
| | - Naveed Hussain
- Department of Pediatrics, University of Connecticut School of Medicine, Farmington, Connecticut
- Division of Neonatal Medicine, Connecticut Children's Medical Center, Hartford, Connecticut
| | - Juan A. Sanchez
- Molecular Cardiology and Angiogenesis Laboratory, Department of Surgery, University of Connecticut Health Center, Farmington, Connecticut
| | - Nilanjana Maulik
- Molecular Cardiology and Angiogenesis Laboratory, Department of Surgery, University of Connecticut Health Center, Farmington, Connecticut
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JUNG KYUNGHEE, YAN HONGHUA, FANG ZHENGHUAN, SON MIKWON, LEE HYUNSEUNG, HONG SUNGWOO, HONG SOONSUN. HS-104, a PI3K inhibitor, enhances the anticancer efficacy of gemcitabine in pancreatic cancer. Int J Oncol 2014; 45:311-21. [DOI: 10.3892/ijo.2014.2435] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 04/03/2014] [Indexed: 11/06/2022] Open
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Piccoli C, Agriesti F, Scrima R, Falzetti F, Di Ianni M, Capitanio N. To breathe or not to breathe: the haematopoietic stem/progenitor cells dilemma. Br J Pharmacol 2014; 169:1652-71. [PMID: 23714011 DOI: 10.1111/bph.12253] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2013] [Revised: 05/11/2013] [Accepted: 05/16/2013] [Indexed: 12/13/2022] Open
Abstract
UNLABELLED Adult haematopoietic stem/progenitor cells (HSPCs) constitute the lifespan reserve for the generation of all the cellular lineages in the blood. Although massive progress in identifying the cluster of master genes controlling self-renewal and multipotency has been achieved in the past decade, some aspects of the physiology of HSPCs still need to be clarified. In particular, there is growing interest in the metabolic profile of HSPCs in view of their emerging role as determinants of cell fate. Indeed, stem cells and progenitors have distinct metabolic profiles, and the transition from stem to progenitor cell corresponds to a critical metabolic change, from glycolysis to oxidative phosphorylation. In this review, we summarize evidence, reported in the literature and provided by our group, highlighting the peculiar ability of HSPCs to adapt their mitochondrial oxidative/bioenergetic metabolism to survive in the hypoxic microenvironment of the endoblastic niche and to exploit redox signalling in controlling the balance between quiescence versus active cycling and differentiation. Especial prominence is given to the interplay between hypoxia inducible factor-1, globins and NADPH oxidases in managing the mitochondrial dioxygen-related metabolism and biogenesis in HSPCs under different ambient conditions. A mechanistic model is proposed whereby 'mitochondrial differentiation' is a prerequisite in uncommitted stem cells, paving the way for growth/differentiation factor-dependent processes. Advancing the understanding of stem cell metabolism will, hopefully, help to (i) improve efforts to maintain, expand and manipulate HSPCs ex vivo and realize their potential therapeutic benefits in regenerative medicine; (ii) reprogramme somatic cells to generate stem cells; and (iii) eliminate, selectively, malignant stem cells. LINKED ARTICLES This article is part of a themed section on Emerging Therapeutic Aspects in Oncology. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2013.169.issue-8.
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Affiliation(s)
- C Piccoli
- Department of Medical and Experimental Medicine, University of Foggia, Foggia, Italy.
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Dehne N, Brüne B. Sensors, transmitters, and targets in mitochondrial oxygen shortage-a hypoxia-inducible factor relay story. Antioxid Redox Signal 2014; 20:339-52. [PMID: 22794181 DOI: 10.1089/ars.2012.4776] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
SIGNIFICANCE Cells sense and respond to a shortage of oxygen by activating the hypoxia-inducible transcription factors HIF-1 and HIF-2 and evoking adaptive responses. RECENT ADVANCES Mitochondria are at the center of a hypoxia sensing and responding relay system. CRITICAL ISSUES Under normoxia, reactive oxygen species (ROS) and nitric oxide (NO) are HIF activators. As their individual flux rates determine their diffusion-controlled interaction, predictions how these radicals affect HIF appear context-dependent. Considering that the oxygen requirement for NO formation limits its role in activating HIF to conditions of ambient oxygen tension. Given the central role of mitochondrial complex IV as a NO target, especially under hypoxia, allows inhibition of mitochondrial respiration by NO to spare oxygen thus, raising the threshold for HIF activation. HIF targets seem to configure a feedback-signaling circuit aimed at gradually adjusting mitochondrial function. In hypoxic cancer cells, mitochondria redirect Krebs cycle intermediates to preserve their biosynthetic ability. Persistent HIF activation lowers the entry of electron-delivering compounds into mitochondria to reduce Krebs cycle fueling and β-oxidation, attenuates the expression of electron transport chain components, limits mitochondria biosynthesis, and provokes their removal by autophagy. FUTURE DIRECTIONS Mitochondria can be placed central in a hypoxia sensing-hypoxia responding circuit. We need to determine to which extent and how mitochondria contribute to sense hypoxia, explore whether modulating their oxygen-consuming capacity redirects hypoxic responses in in vivo relevant disease conditions, and elucidate how the multiple HIF targets in mitochondria shape conditions of acute versus chronic hypoxia.
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Affiliation(s)
- Nathalie Dehne
- Faculty of Medicine, Institute of Biochemistry I/ZAFES, Goethe-University Frankfurt , Frankfurt, Germany
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Hasseldam H, Hansen-Schwartz J, Munkholm N, Hou J, Johansen FF. Remote post-conditioning reduces hypoxic damage early after experimental stroke. Neurol Res 2013; 35:336-43. [PMID: 23540402 DOI: 10.1179/1743132812y.0000000130] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVES Given that reliable markers for early ischemic brain damage are lacking, we set out to test whether pimonidazole can be used as a reliable tool in the quantification of hypoxic insults, at early time points following experimental stroke. METHODS We have used semi-quantitative Western blotting detection of pimonidazole adducts in a rat model of reversible middle cerebral artery occlusion (MCAO), treated with remote post-conditioning. RESULTS First, we demonstrated that a linear relationship exist between pimonidazole binding in the ischemic hemisphere and duration of ischemia, in animals subjected to 5, 15, 30, or 60 minutes of occlusion followed by 120 minutes of reflow. Then we showed a significant reduction in pimonidazole binding in the infarcted hemisphere, when rats with 60 minutes of MCAO, immediately after establishment of cerebral reflow, had 3×15 minutes intermittent hind limb ischemia followed by 24-hour survival. We analysed the middle cerebral arteries from animals with 60 minutes of MCAO and early remote post-conditioning, followed by 30 minutes, 24, or 48 hours of reflow. At 24 hours of reflow increases in phosphorylated protein kinase C-alpha with concomitantly increased levels of p38 phosphorylation were observed. CONCLUSIONS Our investigation demonstrates that pimonidazole can be used for quantifying ischemic impact in stroke, even after very short survival times. It furthermore shows that early remote post-conditioning reduces ischemic damage, probably through hyperpolarization and reduced reflow vasospasm in the conduit middle cerebral arteries.
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Takahashi E, Sato M. Anaerobic respiration sustains mitochondrial membrane potential in a prolyl hydroxylase pathway-activated cancer cell line in a hypoxic microenvironment. Am J Physiol Cell Physiol 2013; 306:C334-42. [PMID: 24048731 DOI: 10.1152/ajpcell.00255.2013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
To elucidate how tumor cells produce energy in oxygen-depleted microenvironments, we studied the possibility of mitochondrial electron transport without oxygen. We produced well-controlled oxygen gradients (ΔO2) in monolayer-cultured cells. We then visualized oxygen levels and mitochondrial membrane potential (ΔΦm) in individual cells by using the red shift of green fluorescent protein (GFP) fluorescence and a cationic fluorescent dye, respectively. In this two-dimensional tissue model, ΔΦm was abolished in cells >500 μm from the oxygen source [the anoxic front (AF)], indicating limitations in diffusional oxygen delivery. This result perfectly matched GFP-determined ΔO2. In cells pretreated with dimethyloxaloylglycine (DMOG), a prolyl hydroxylase domain-containing protein (PHD) inhibitor, the AF was expanded to 1,500-2,000 μm from the source. In these cells, tissue ΔO2 was substantially decreased, indicating that PHD pathway activation suppressed mitochondrial respiration. The expansion of the AF and the reduction of ΔO2 were much more prominent in a cancer cell line (Hep3B) than in the equivalent fibroblast-like cell line (COS-7). Hence, the results indicate that PHD pathway-activated cells can sustain ΔΦm, despite significantly decreased electron flux to complex IV. Complex II inhibition abolished the effect of DMOG in expanding the AF, although tissue ΔO2 remained shallow. Separate experiments demonstrated that complex II plays a substantial role in sustaining ΔΦm in DMOG-pretreated Hep3B cells with complex III inhibition. From these results, we conclude that PHD pathway activation can sustain ΔΦm in an otherwise anoxic microenvironment by decreasing tissue ΔO2 while activating oxygen-independent electron transport in mitochondria.
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Affiliation(s)
- Eiji Takahashi
- Advanced Technology Fusion, Graduate School of Science and Engineering, Saga University, Saga, Japan; and
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29
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Brüne B, Dehne N, Grossmann N, Jung M, Namgaladze D, Schmid T, von Knethen A, Weigert A. Redox control of inflammation in macrophages. Antioxid Redox Signal 2013; 19:595-637. [PMID: 23311665 PMCID: PMC3718318 DOI: 10.1089/ars.2012.4785] [Citation(s) in RCA: 275] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 12/14/2012] [Accepted: 01/11/2013] [Indexed: 12/13/2022]
Abstract
Macrophages are present throughout the human body, constitute important immune effector cells, and have variable roles in a great number of pathological, but also physiological, settings. It is apparent that macrophages need to adjust their activation profile toward a steadily changing environment that requires altering their phenotype, a process known as macrophage polarization. Formation of reactive oxygen species (ROS), derived from NADPH-oxidases, mitochondria, or NO-producing enzymes, are not necessarily toxic, but rather compose a network signaling system, known as redox regulation. Formation of redox signals in classically versus alternatively activated macrophages, their action and interaction at the level of key targets, and the resulting physiology still are insufficiently understood. We review the identity, source, and biological activities of ROS produced during macrophage activation, and discuss how they shape the key transcriptional responses evoked by hypoxia-inducible transcription factors, nuclear-erythroid 2-p45-related factor 2 (Nrf2), and peroxisome proliferator-activated receptor-γ. We summarize the mechanisms how redox signals add to the process of macrophage polarization and reprogramming, how this is controlled by the interaction of macrophages with their environment, and addresses the outcome of the polarization process in health and disease. Future studies need to tackle the option whether we can use the knowledge of redox biology in macrophages to shape their mediator profile in pathophysiology, to accelerate healing in injured tissue, to fight the invading pathogens, or to eliminate settings of altered self in tumors.
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Affiliation(s)
- Bernhard Brüne
- Faculty of Medicine, Institute of Biochemistry I-Pathobiochemistry, Goethe-University Frankfurt, Frankfurt, Germany.
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30
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Bafilomycin A1 activates HIF-dependent signalling in human colon cancer cells via mitochondrial uncoupling. Biosci Rep 2013; 32:587-95. [PMID: 22943412 PMCID: PMC3497721 DOI: 10.1042/bsr20120085] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Mitochondrial uncoupling is implicated in many patho(physiological) states. Using confocal live cell imaging and an optical O2 sensing technique, we show that moderate uncoupling of the mitochondria with plecomacrolide Baf (bafilomycin A1) causes partial depolarization of the mitochondria and deep sustained deoxygenation of human colon cancer HCT116 cells subjected to 6% atmospheric O2. A decrease in iO2 (intracellular O2) to 0–10 μM, induced by Baf, is sufficient for stabilization of HIFs (hypoxia inducible factors) HIF-1α and HIF-2α, coupled with an increased expression of target genes including GLUT1 (glucose transporter 1), HIF PHD2 (prolyl hydroxylase domain 2) and CAIX (carbonic anhydrase IX). Under the same hypoxic conditions, treatment with Baf causes neither decrease in iO2 nor HIF-α stabilization in the low-respiring HCT116 cells deficient in COX (cytochrome c-oxidase). Both cell types display equal capacities for HIF-α stabilization by hypoxia mimetics DMOG (dimethyloxalylglycine) and CoCl2, thus suggesting that the effect of Baf under hypoxia is driven mainly by mitochondrial respiration. Altogether, by activating HIF signalling under moderate hypoxia, mitochondrial uncoupling can play an important regulatory role in colon cancer metabolism and modulate adaptation of cancer cells to natural hypoxic environments.
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Das S, Singh S, Dowding JM, Oommen S, Kumar A, Sayle TXT, Saraf S, Patra CR, Vlahakis NE, Sayle DC, Self WT, Seal S. The induction of angiogenesis by cerium oxide nanoparticles through the modulation of oxygen in intracellular environments. Biomaterials 2012; 33:7746-55. [PMID: 22858004 PMCID: PMC4590782 DOI: 10.1016/j.biomaterials.2012.07.019] [Citation(s) in RCA: 208] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Accepted: 07/06/2012] [Indexed: 01/14/2023]
Abstract
Angiogenesis is the formation of new blood vessels from existing blood vessels and is critical for many physiological and pathophysiological processes. In this study we have shown the unique property of cerium oxide nanoparticles (CNPs) to induce angiogenesis, observed using both in vitro and in vivo model systems. In particular, CNPs trigger angiogenesis by modulating the intracellular oxygen environment and stabilizing hypoxia inducing factor 1α endogenously. Furthermore, correlations between angiogenesis induction and CNPs physicochemical properties including: surface Ce(3+)/Ce(4+) ratio, surface charge, size, and shape were also explored. High surface area and increased Ce(3+)/Ce(4+) ratio make CNPs more catalytically active towards regulating intracellular oxygen, which in turn led to more robust induction of angiogenesis. Atomistic simulation was also used, in partnership with in vitro and in vivo experimentation, to reveal that the surface reactivity of CNPs and facile oxygen transport promotes pro-angiogenesis.
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Affiliation(s)
- Soumen Das
- Department of Mechanical, Materials and Aerospace Engineering, Advanced Materials Processing Analysis Center, University of Central Florida, Orlando, Florida
| | - Sanjay Singh
- Burnett School of Biomedical Science, University of Central Florida, Orlando, Florida
| | - Janet M. Dowding
- Burnett School of Biomedical Science, University of Central Florida, Orlando, Florida
| | - Saji Oommen
- Div. Pulmonary & Critical Care, Mayo Clinic, Rochester, Minnesota, USA
| | - Amit Kumar
- Department of Mechanical, Materials and Aerospace Engineering, Advanced Materials Processing Analysis Center, University of Central Florida, Orlando, Florida
| | - Thi X. T. Sayle
- Department of Engineering and Applied Science, Cranfield University, Defence Academy of the United Kingdom, Shrivenham SN6 8LA, United Kingdom
| | - Shashank Saraf
- Department of Mechanical, Materials and Aerospace Engineering, Advanced Materials Processing Analysis Center, University of Central Florida, Orlando, Florida
| | - Chitta Ranjan Patra
- Department of Biochemistry and Molecular Biology Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | | | - Dean C. Sayle
- Department of Engineering and Applied Science, Cranfield University, Defence Academy of the United Kingdom, Shrivenham SN6 8LA, United Kingdom
| | - William T. Self
- Burnett School of Biomedical Science, University of Central Florida, Orlando, Florida
| | - Sudipta Seal
- Department of Mechanical, Materials and Aerospace Engineering, Advanced Materials Processing Analysis Center, University of Central Florida, Orlando, Florida
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Oxygen versus Reactive Oxygen in the Regulation of HIF-1α: The Balance Tips. Biochem Res Int 2012; 2012:436981. [PMID: 23091723 PMCID: PMC3474226 DOI: 10.1155/2012/436981] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 09/14/2012] [Accepted: 09/15/2012] [Indexed: 12/02/2022] Open
Abstract
Hypoxia inducible factor (HIF) is known as the master regulator of the cellular response to hypoxia and is of pivotal importance during development as well as in human disease, particularly in cancer. It is composed of a constitutively expressed β subunit (HIF-1β) and an oxygen-regulated α subunit (HIF-1α and HIF-2α), whose stability is tightly controlled by a family of oxygen- and iron-dependent prolyl hydroxylase enzymes. Whether or not mitochondria-derived reactive oxygen species (ROS) are involved in the regulation of Hypoxia Inducible Factor-1α has been a matter of contention for the last 10 years, with equally compelling evidence in favor and against their contribution. A number of recent papers appear to tip the balance against a role for ROS. Thus, it has been demonstrated that HIF prolyl hydroxylases are unlikely to be physiological targets of ROS and that the increase in ROS that is associated with downregulation of Thioredoxin Reductase in hypoxia does not affect HIF-1α stabilization. Finally, the protein CHCHD4, which modulates cellular HIF-1α concentrations by promoting mitochondrial electron transport chain activity, has been proposed to exert its regulatory effect by affecting cellular oxygen availability. These reports are consistent with the hypothesis that mitochondria play a critical role in the regulation of HIF-1α by controlling intracellular oxygen concentrations.
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Prabhakar NR, Semenza GL. Adaptive and maladaptive cardiorespiratory responses to continuous and intermittent hypoxia mediated by hypoxia-inducible factors 1 and 2. Physiol Rev 2012; 92:967-1003. [PMID: 22811423 DOI: 10.1152/physrev.00030.2011] [Citation(s) in RCA: 429] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Hypoxia is a fundamental stimulus that impacts cells, tissues, organs, and physiological systems. The discovery of hypoxia-inducible factor-1 (HIF-1) and subsequent identification of other members of the HIF family of transcriptional activators has provided insight into the molecular underpinnings of oxygen homeostasis. This review focuses on the mechanisms of HIF activation and their roles in physiological and pathophysiological responses to hypoxia, with an emphasis on the cardiorespiratory systems. HIFs are heterodimers comprised of an O(2)-regulated HIF-1α or HIF-2α subunit and a constitutively expressed HIF-1β subunit. Induction of HIF activity under conditions of reduced O(2) availability requires stabilization of HIF-1α and HIF-2α due to reduced prolyl hydroxylation, dimerization with HIF-1β, and interaction with coactivators due to decreased asparaginyl hydroxylation. Stimuli other than hypoxia, such as nitric oxide and reactive oxygen species, can also activate HIFs. HIF-1 and HIF-2 are essential for acute O(2) sensing by the carotid body, and their coordinated transcriptional activation is critical for physiological adaptations to chronic hypoxia including erythropoiesis, vascularization, metabolic reprogramming, and ventilatory acclimatization. In contrast, intermittent hypoxia, which occurs in association with sleep-disordered breathing, results in an imbalance between HIF-1α and HIF-2α that causes oxidative stress, leading to cardiorespiratory pathology.
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Affiliation(s)
- Nanduri R Prabhakar
- Institute for Integrative Physiology and Center for Systems Biology of O2 Sensing, Biological Sciences Division, University of Chicago, Chicago, Illinois, USA.
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34
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Ong SG, Hausenloy DJ. Hypoxia-inducible factor as a therapeutic target for cardioprotection. Pharmacol Ther 2012; 136:69-81. [PMID: 22800800 DOI: 10.1016/j.pharmthera.2012.07.005] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Accepted: 06/18/2012] [Indexed: 10/28/2022]
Abstract
Hypoxia inducible factor (HIF) is an oxygen-sensitive transcription factor that enables aerobic organisms to adapt to hypoxia. This is achieved through the transcriptional activation of up to 200 genes, many of which are critical to cell survival. Under conditions of normoxia, the hydroxylation of HIF by prolyl hydroxylase domain-containing (PHD) enzymes targets it for polyubiquitination and proteosomal degradation by the von Hippel-Lindau protein (VHL). However, under hypoxic conditions, PHD activity is inhibited, thereby allowing HIF to accumulate and translocate to the nucleus, where it binds to the hypoxia-responsive element sequences of target gene promoters. Experimental studies suggest that HIF may act as a mediator of ischemic preconditioning, and that the genetic or pharmacological stabilization of HIF under normoxic conditions, may protect the heart against the detrimental effects of acute ischemia-reperfusion injury. The mechanisms underlying the cardioprotective effect of HIF are unclear, but it may be attributed to the transcriptional activation of genes associated with cardioprotection such as erythropoietin, heme oxygenase-1, and inducible nitric oxide synthase or it may be due to reprogramming of cell metabolism. In this review article, we highlight the role of HIF in mediating both adaptive and pathological processes in the heart, as well as focusing on the therapeutic potential of the HIF-signaling pathway as a target for cardioprotection.
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Affiliation(s)
- Sang-Ging Ong
- The Hatter Cardiovascular Institute, University College London Hospital, 67 Chenies Mews, London WC1E 6HX, United Kingdom
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Yang J, Staples O, Thomas LW, Briston T, Robson M, Poon E, Simões ML, El-Emir E, Buffa FM, Ahmed A, Annear NP, Shukla D, Pedley BR, Maxwell PH, Harris AL, Ashcroft M. Human CHCHD4 mitochondrial proteins regulate cellular oxygen consumption rate and metabolism and provide a critical role in hypoxia signaling and tumor progression. J Clin Invest 2012; 122:600-11. [PMID: 22214851 PMCID: PMC3266784 DOI: 10.1172/jci58780] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Accepted: 11/16/2011] [Indexed: 11/17/2022] Open
Abstract
Increased expression of the regulatory subunit of HIFs (HIF-1α or HIF-2α) is associated with metabolic adaptation, angiogenesis, and tumor progression. Understanding how HIFs are regulated is of intense interest. Intriguingly, the molecular mechanisms that link mitochondrial function with the HIF-regulated response to hypoxia remain to be unraveled. Here we describe what we believe to be novel functions of the human gene CHCHD4 in this context. We found that CHCHD4 encodes 2 alternatively spliced, differentially expressed isoforms (CHCHD4.1 and CHCHD4.2). CHCHD4.1 is identical to MIA40, the homolog of yeast Mia40, a key component of the mitochondrial disulfide relay system that regulates electron transfer to cytochrome c. Further analysis revealed that CHCHD4 proteins contain an evolutionarily conserved coiled-coil-helix-coiled-coil-helix (CHCH) domain important for mitochondrial localization. Modulation of CHCHD4 protein expression in tumor cells regulated cellular oxygen consumption rate and metabolism. Targeting CHCHD4 expression blocked HIF-1α induction and function in hypoxia and resulted in inhibition of tumor growth and angiogenesis in vivo. Overexpression of CHCHD4 proteins in tumor cells enhanced HIF-1α protein stabilization in hypoxic conditions, an effect insensitive to antioxidant treatment. In human cancers, increased CHCHD4 expression was found to correlate with the hypoxia gene expression signature, increasing tumor grade, and reduced patient survival. Thus, our study identifies a mitochondrial mechanism that is critical for regulating the hypoxic response in tumors.
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Affiliation(s)
- Jun Yang
- Centre for Cell Signalling and Molecular Genetics, University College London, Division of Medicine, Rayne Institute, London, United Kingdom.
Tumour Biology Section, UCL Cancer Institute, Paul O’Gorman Building, University College London, London, United Kingdom.
Cancer Research UK Department of Medical Oncology, The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom.
Faculty of Medical Sciences, University College London, Division of Medicine, Rayne Institute, London, United Kingdom
| | - Oliver Staples
- Centre for Cell Signalling and Molecular Genetics, University College London, Division of Medicine, Rayne Institute, London, United Kingdom.
Tumour Biology Section, UCL Cancer Institute, Paul O’Gorman Building, University College London, London, United Kingdom.
Cancer Research UK Department of Medical Oncology, The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom.
Faculty of Medical Sciences, University College London, Division of Medicine, Rayne Institute, London, United Kingdom
| | - Luke W. Thomas
- Centre for Cell Signalling and Molecular Genetics, University College London, Division of Medicine, Rayne Institute, London, United Kingdom.
Tumour Biology Section, UCL Cancer Institute, Paul O’Gorman Building, University College London, London, United Kingdom.
Cancer Research UK Department of Medical Oncology, The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom.
Faculty of Medical Sciences, University College London, Division of Medicine, Rayne Institute, London, United Kingdom
| | - Thomas Briston
- Centre for Cell Signalling and Molecular Genetics, University College London, Division of Medicine, Rayne Institute, London, United Kingdom.
Tumour Biology Section, UCL Cancer Institute, Paul O’Gorman Building, University College London, London, United Kingdom.
Cancer Research UK Department of Medical Oncology, The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom.
Faculty of Medical Sciences, University College London, Division of Medicine, Rayne Institute, London, United Kingdom
| | - Mathew Robson
- Centre for Cell Signalling and Molecular Genetics, University College London, Division of Medicine, Rayne Institute, London, United Kingdom.
Tumour Biology Section, UCL Cancer Institute, Paul O’Gorman Building, University College London, London, United Kingdom.
Cancer Research UK Department of Medical Oncology, The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom.
Faculty of Medical Sciences, University College London, Division of Medicine, Rayne Institute, London, United Kingdom
| | - Evon Poon
- Centre for Cell Signalling and Molecular Genetics, University College London, Division of Medicine, Rayne Institute, London, United Kingdom.
Tumour Biology Section, UCL Cancer Institute, Paul O’Gorman Building, University College London, London, United Kingdom.
Cancer Research UK Department of Medical Oncology, The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom.
Faculty of Medical Sciences, University College London, Division of Medicine, Rayne Institute, London, United Kingdom
| | - Maria L. Simões
- Centre for Cell Signalling and Molecular Genetics, University College London, Division of Medicine, Rayne Institute, London, United Kingdom.
Tumour Biology Section, UCL Cancer Institute, Paul O’Gorman Building, University College London, London, United Kingdom.
Cancer Research UK Department of Medical Oncology, The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom.
Faculty of Medical Sciences, University College London, Division of Medicine, Rayne Institute, London, United Kingdom
| | - Ethaar El-Emir
- Centre for Cell Signalling and Molecular Genetics, University College London, Division of Medicine, Rayne Institute, London, United Kingdom.
Tumour Biology Section, UCL Cancer Institute, Paul O’Gorman Building, University College London, London, United Kingdom.
Cancer Research UK Department of Medical Oncology, The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom.
Faculty of Medical Sciences, University College London, Division of Medicine, Rayne Institute, London, United Kingdom
| | - Francesca M. Buffa
- Centre for Cell Signalling and Molecular Genetics, University College London, Division of Medicine, Rayne Institute, London, United Kingdom.
Tumour Biology Section, UCL Cancer Institute, Paul O’Gorman Building, University College London, London, United Kingdom.
Cancer Research UK Department of Medical Oncology, The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom.
Faculty of Medical Sciences, University College London, Division of Medicine, Rayne Institute, London, United Kingdom
| | - Afshan Ahmed
- Centre for Cell Signalling and Molecular Genetics, University College London, Division of Medicine, Rayne Institute, London, United Kingdom.
Tumour Biology Section, UCL Cancer Institute, Paul O’Gorman Building, University College London, London, United Kingdom.
Cancer Research UK Department of Medical Oncology, The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom.
Faculty of Medical Sciences, University College London, Division of Medicine, Rayne Institute, London, United Kingdom
| | - Nicholas P. Annear
- Centre for Cell Signalling and Molecular Genetics, University College London, Division of Medicine, Rayne Institute, London, United Kingdom.
Tumour Biology Section, UCL Cancer Institute, Paul O’Gorman Building, University College London, London, United Kingdom.
Cancer Research UK Department of Medical Oncology, The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom.
Faculty of Medical Sciences, University College London, Division of Medicine, Rayne Institute, London, United Kingdom
| | - Deepa Shukla
- Centre for Cell Signalling and Molecular Genetics, University College London, Division of Medicine, Rayne Institute, London, United Kingdom.
Tumour Biology Section, UCL Cancer Institute, Paul O’Gorman Building, University College London, London, United Kingdom.
Cancer Research UK Department of Medical Oncology, The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom.
Faculty of Medical Sciences, University College London, Division of Medicine, Rayne Institute, London, United Kingdom
| | - Barbara R. Pedley
- Centre for Cell Signalling and Molecular Genetics, University College London, Division of Medicine, Rayne Institute, London, United Kingdom.
Tumour Biology Section, UCL Cancer Institute, Paul O’Gorman Building, University College London, London, United Kingdom.
Cancer Research UK Department of Medical Oncology, The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom.
Faculty of Medical Sciences, University College London, Division of Medicine, Rayne Institute, London, United Kingdom
| | - Patrick H. Maxwell
- Centre for Cell Signalling and Molecular Genetics, University College London, Division of Medicine, Rayne Institute, London, United Kingdom.
Tumour Biology Section, UCL Cancer Institute, Paul O’Gorman Building, University College London, London, United Kingdom.
Cancer Research UK Department of Medical Oncology, The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom.
Faculty of Medical Sciences, University College London, Division of Medicine, Rayne Institute, London, United Kingdom
| | - Adrian L. Harris
- Centre for Cell Signalling and Molecular Genetics, University College London, Division of Medicine, Rayne Institute, London, United Kingdom.
Tumour Biology Section, UCL Cancer Institute, Paul O’Gorman Building, University College London, London, United Kingdom.
Cancer Research UK Department of Medical Oncology, The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom.
Faculty of Medical Sciences, University College London, Division of Medicine, Rayne Institute, London, United Kingdom
| | - Margaret Ashcroft
- Centre for Cell Signalling and Molecular Genetics, University College London, Division of Medicine, Rayne Institute, London, United Kingdom.
Tumour Biology Section, UCL Cancer Institute, Paul O’Gorman Building, University College London, London, United Kingdom.
Cancer Research UK Department of Medical Oncology, The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom.
Faculty of Medical Sciences, University College London, Division of Medicine, Rayne Institute, London, United Kingdom
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Dubé A, Harrisson JF, Saint-Gelais G, Séguin C. Hypoxia acts through multiple signaling pathways to induce metallothionein transactivation by the metal-responsive transcription factor-1 (MTF-1). Biochem Cell Biol 2011; 89:562-77. [PMID: 22087877 PMCID: PMC4020849 DOI: 10.1139/o11-063] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Metal-responsive transcription factor-1 (MTF-1) is essential for the induction of genes encoding metallothionein by metals and hypoxia. Here, we studied the mechanism controlling the activation of MTF-1 by hypoxia. Hypoxia activation of Mt gene transcription is dependent on the presence of metal regulatory elements (MREs) in the promoter of Mt genes. We showed that MREa and MREd are the main elements controlling mouse Mt-1 gene induction by hypoxia. Transfection experiments in Mtf-1-null cells showed that MTF-1 is essential for induction by hypoxia. Chromatin immunoprecipitation analysis showed that MTF-1 DNA-binding activity was strongly enhanced in the presence of zinc but not by hypoxia. Notably, hypoxia inducible factor- (HIF) 1α was recruited to the Mt-1 promoter in response to hypoxia but not to zinc. MTF-1 activation was inhibited by PKC, JNK, and PI3K inhibitors and by the electron transport chain inhibitors rotenone and myxothiazol, but not by the antioxidant N-acetylcysteine. We showed that prolyl-hydroxylase inhibitors can activate MTF-1, but this activation requires the presence of HIF-1α. Finally, HIF-dependent transcription is enhanced in the presence of MTF-1 and induction of an MRE promoter is stimulated by HIF-1α, thus indicating cooperation between these 2 factors. However, coimmunoprecipitation experiments did not suggest direct interaction between MTF-1 and HIF-1α.
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Affiliation(s)
- Annie Dubé
- Centre de recherche en cancérologie de l'Université Laval, CHUQ, Hôtel-Dieu de QC, 9, rue McMahon, QC G1R 2J6, Canada
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Activation of hypoxia-inducible factor 1 in skeletal muscle cells after exposure to damaged muscle cell debris. Shock 2011; 35:632-8. [PMID: 21283061 DOI: 10.1097/shk.0b013e3182111f3d] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Skeletal muscle damage provokes complex repair mechanisms including recruitment of leukocytes as well as activation of myogenic precursor cells such as satellite cells. To study muscle cell repair mechanisms after muscle fiber damage, we used an in vitro model of scrape-injured myotubes. Exposing vital C2C12 myoblasts and myotubes to cell debris of damaged myotubes revealed mRNA upregulation of adrenomedullin (ADM), insulin-like growth factors 1 and 2, metallopeptidase 9, and monocyte chemoattractant protein11. When cell debris was treated with ultrasound, frozen in liquid nitrogen, or heat inactivated before addition to C2C12 cells, gene expression was drastically reduced or completely absent. Moreover, incubations of myoblasts with debris separated by transwell inserts indicated that direct cell contact is required for gene induction. Incubation with albumin and PolyIC ruled out that ADM induction by cell debris simply results from increased protein or nucleic acid concentrations in the supernatant. Because the genes, which were upregulated by cell debris, are potential target genes of hypoxia-inducible factor (HIF), cells were analyzed for HIF-1α expression. Western blot analysis showed accumulation of the α-subunit upon contact to cell debris. Knockdown of HIF-1α in C2C12 cells proved that activation of HIF-1 in response to cell debris was responsible for upregulating ADM and monocyte chemoattractant protein 1. Furthermore, by incubating cells on gas-permeable culture dishes, we excluded a reduced pericellular pO2 induced by cell debris as the cause for ADM upregulation. Our data suggest that damaged myofibers activate HIF-1 in neighboring myotubes and precursor myoblasts by direct contact, concomitantly upregulating factors necessary for angiogenesis, tissue regeneration, and phagocyte recruitment.
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Takahashi E, Sato M. Impact of intracellular diffusion of oxygen in hypoxic sensing. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 701:301-6. [PMID: 21445801 DOI: 10.1007/978-1-4419-7756-4_40] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Hypoxia-inducible factor 1 (HIF-1) is the key to genetic adaptations to hypoxia in eukaryotes. In vivo, capillary pO(2) and extracellular- and intracellular- O(2) gradients define pO2 at the O(2) labile subunit HIF-1α.With a novel technique for subcellular imaging of O(2) heterogeneity using GFP, the present study was undertaken to examine the possibility that changes in mitochondrial respiration significantly affect intracellular O(2) gradients and thus, HIF-1 expression.We failed to demonstrate consistent changes in intracellular O(2) distributions in cultured cells with different metabolic and morphological properties (COS-7, Hep G2, and Hep3B cells) while mitochondrial O(2) consumption was widely changed at 1%O(2).Thus,we conclude that conductance for intracellular diffusion of O(2) is high in these cells and intracellular O(2) gradients might not be involved in the regulation of HIF-1 expression in vivo.
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Affiliation(s)
- Eiji Takahashi
- Department of Physiology, Yamagata University School of Medicine, Yamagata, Japan.
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Tian YM, Yeoh KK, Lee MK, Eriksson T, Kessler BM, Kramer HB, Edelmann MJ, Willam C, Pugh CW, Schofield CJ, Ratcliffe PJ. Differential sensitivity of hypoxia inducible factor hydroxylation sites to hypoxia and hydroxylase inhibitors. J Biol Chem 2011; 286:13041-51. [PMID: 21335549 PMCID: PMC3075650 DOI: 10.1074/jbc.m110.211110] [Citation(s) in RCA: 139] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Hypoxia inducible factor (HIF) is regulated by dual pathways involving oxygen-dependent prolyl and asparaginyl hydroxylation of its α-subunits. Prolyl hydroxylation at two sites within a central degradation domain promotes association of HIF-α with the von Hippel-Lindau ubiquitin E3 ligase and destruction by the ubiquitin-proteasome pathways. Asparaginyl hydroxylation blocks the recruitment of p300/CBP co-activators to a C-terminal activation domain in HIF-α. These hydroxylations are catalyzed by members of the Fe(II) and 2-oxoglutarate (2-OG) oxygenase family. Activity of the enzymes is suppressed by hypoxia, increasing both the abundance and activity of the HIF transcriptional complex. We have used hydroxy residue-specific antibodies to compare and contrast the regulation of each site of prolyl hydroxylation (Pro402, Pro564) with that of asparaginyl hydroxylation (Asn803) in human HIF-1α. Our findings reveal striking differences in the sensitivity of these hydroxylations to hypoxia and to different inhibitor types of 2-OG oxygenases. Hydroxylation at the three sites in endogenous human HIF-1α proteins was suppressed by hypoxia in the order Pro402 > Pro564 > Asn803. In contrast to some predictions from in vitro studies, prolyl hydroxylation was substantially more sensitive than asparaginyl hydroxylation to inhibition by iron chelators and transition metal ions; studies of a range of different small molecule 2-OG analogues demonstrated the feasibility of selectively inhibiting either prolyl or asparaginyl hydroxylation within cells.
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Affiliation(s)
- Ya-Min Tian
- Nuffield Department of Clinical Medicine, Henry Wellcome Building for Molecular Physiology, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, United Kingdom
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Sato Y, Endo H, Okuyama H, Takeda T, Iwahashi H, Imagawa A, Yamagata K, Shimomura I, Inoue M. Cellular hypoxia of pancreatic beta-cells due to high levels of oxygen consumption for insulin secretion in vitro. J Biol Chem 2011; 286:12524-32. [PMID: 21296882 DOI: 10.1074/jbc.m110.194738] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cellular oxygen consumption is a determinant of intracellular oxygen levels. Because of the high demand of mitochondrial respiration during insulin secretion, pancreatic β-cells consume large amounts of oxygen in a short time period. We examined the effect of insulin secretion on cellular oxygen tension in vitro. We confirmed that Western blotting of pimonidazole adduct was more sensitive than immunostaining for detection of cellular hypoxia in vitro and in vivo. The islets of the diabetic mice but not those of normal mice were hypoxic, especially when a high dose of glucose was loaded. In MIN6 cells, a pancreatic β-cell line, pimonidazole adduct formation and stabilization of hypoxia-inducible factor-1α (HIF-1α) were detected under mildly hypoxic conditions. Inhibition of respiration rescued the cells from becoming hypoxic. Glucose stimulation decreased cellular oxygen levels in parallel with increased insulin secretion and mitochondrial respiration. The cellular hypoxia by glucose stimulation was also observed in the isolated islets from mice. The MIN6 cells overexpressing HIF-1α were resistant to becoming hypoxic after glucose stimulation. Thus, glucose-stimulated β-cells can become hypoxic by oxygen consumption, especially when the oxygen supply is impaired.
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Affiliation(s)
- Yoshifumi Sato
- Department of Biochemistry, Osaka Medical Center for Cancer and Cardiovascular Diseases, 1-3-3 Nakamichi, Higashinari-ku, Osaka 537-8511
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Takahashi E, Sato M. Imaging of oxygen gradients in monolayer cultured cells using green fluorescent protein. Am J Physiol Cell Physiol 2010; 299:C1318-23. [DOI: 10.1152/ajpcell.00254.2010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Gradients of Po2 between capillary blood and mitochondria are the driving force for diffusional O2 delivery in tissues. Hypoxic microenvironments in tissues that result from diffusional O2 gradients are especially relevant in solid tumors because they have been related to a poor prognosis. To address the impact of tissue O2 gradients, we developed a novel technique that permits imaging of intracellular O2 levels in cultured cells at a subcellular spatial resolution. This was done, with the sensitivity to O2 ≤3%, by the O2-dependent red shift of green fluorescent protein (AcGFP1) fluorescence. Measurements were carried out in a confluent monolayer of Hep3B cells expressing AcGFP1 in the cytoplasm. To establish a two-dimensional O2 diffusion model, a thin quartz glass slip was placed onto the monolayer cells to prevent O2 diffusion from the top surface of the cell layer. The magnitude of the red shift progressively increased as the distance from the gas coverslip interface increased. It reached an anoxic level in cells located at ∼220 μm and ∼690 μm from the gas coverslip boundary at 1% and 3% gas phase O2, respectively. Thus the average O2 gradient was 0.03 mmHg/μm in the present tissue model. Abolition of mitochondrial respiration significantly dampened the gradients. Furthermore, intracellular gradients of the red shift in mitochondria-targeted AcGFP1 in single Hep3B cells suggest that the origin of tissue O2 gradients is intracellular. Findings in the present two-dimensional O2 diffusion model support the crucial role of tissue O2 diffusion in defining the O2 microenvironment in individual cells.
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Affiliation(s)
- Eiji Takahashi
- Biomedical Engineering Course, Advanced Technology Fusion, Graduate School of Science and Engineering, Saga University, Saga, Japan and
| | - Michihiko Sato
- CLRE, Yamagata University School of Medicine, Yamagata, Japan
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Shlomai J. Redox control of protein-DNA interactions: from molecular mechanisms to significance in signal transduction, gene expression, and DNA replication. Antioxid Redox Signal 2010; 13:1429-76. [PMID: 20446770 DOI: 10.1089/ars.2009.3029] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Protein-DNA interactions play a key role in the regulation of major cellular metabolic pathways, including gene expression, genome replication, and genomic stability. They are mediated through the interactions of regulatory proteins with their specific DNA-binding sites at promoters, enhancers, and replication origins in the genome. Redox signaling regulates these protein-DNA interactions using reactive oxygen species and reactive nitrogen species that interact with cysteine residues at target proteins and their regulators. This review describes the redox-mediated regulation of several master regulators of gene expression that control the induction and suppression of hundreds of genes in the genome, regulating multiple metabolic pathways, which are involved in cell growth, development, differentiation, and survival, as well as in the function of the immune system and cellular response to intracellular and extracellular stimuli. It also discusses the role of redox signaling in protein-DNA interactions that regulate DNA replication. Specificity of redox regulation is discussed, as well as the mechanisms providing several levels of redox-mediated regulation, from direct control of DNA-binding domains through the indirect control, mediated by release of negative regulators, regulation of redox-sensitive protein kinases, intracellular trafficking, and chromatin remodeling.
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Affiliation(s)
- Joseph Shlomai
- Department of Microbiology and Molecular Genetics, The Kuvin Center for the Study of Tropical and Infectious Diseases, Institute for Medical Research Canada-Israel, The Hebrew University-Hadassah Medical School, Jerusalem, Israel.
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Chua YL, Dufour E, Dassa EP, Rustin P, Jacobs HT, Taylor CT, Hagen T. Stabilization of hypoxia-inducible factor-1alpha protein in hypoxia occurs independently of mitochondrial reactive oxygen species production. J Biol Chem 2010; 285:31277-84. [PMID: 20675386 PMCID: PMC2951202 DOI: 10.1074/jbc.m110.158485] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Revised: 07/23/2010] [Indexed: 11/06/2022] Open
Abstract
The transcription factor hypoxia-inducible factor-1α (HIF-1α) is a master regulator of the cellular response to low oxygen. HIF-1α protein accumulates in hypoxia due to inhibition of prolyl hydroxylase enzymes, which under normoxic conditions use molecular oxygen to hydroxylate HIF-1α on two conserved proline residues (Pro(402) and Pro(564)), thus targeting the protein for 26 S proteasome-dependent degradation. A functional mitochondrial electron transport chain is known to be necessary for HIF-1α stabilization in hypoxia. It has been reported that reactive oxygen species (ROS), produced under hypoxia by complex III of the mitochondrial electron transport chain, play a critical role in the stabilization of the HIF-1α protein, possibly by directly inhibiting prolyl hydroxylase enzymes. In contrast, we found that ROS production by complex III is not required for hypoxia-induced HIF-1α stabilization. Thus, reestablishing mitochondrial oxygen consumption in the presence of a complex III inhibitor by using an artificial electron donor to complex IV or by overexpressing Ciona intestinalis alternative oxidase results in HIF-1α protein stabilization in hypoxia. Furthermore, five inhibitors that target different sites of the mitochondrial electron transport chain have similar effects on the HIF-1α protein half-life in hypoxia but vary in their effects on mitochondrial ROS production. Finally, ROS do not regulate prolyl hydroxylase activity directly. We conclude that HIF-1α protein stabilization in hypoxia occurs independently of mitochondrial ROS production. However, mitochondria can modulate the cellular hypoxic response through altered respiratory activity, likely by regulating the cellular oxygen availability.
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Affiliation(s)
- Yee Liu Chua
- From the Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 117597 Singapore
| | - Eric Dufour
- the Institute of Medical Technology and Centre for Laboratory Medicine, Tampere University Hospital, FI-33014 University of Tampere, Finland
| | - Emmanuel P. Dassa
- INSERM U676, Hôpital Robert Debré and Université Paris 7, Faculté de Médecine Denis, Diderot, 75870 Paris, France, and
| | - Pierre Rustin
- INSERM U676, Hôpital Robert Debré and Université Paris 7, Faculté de Médecine Denis, Diderot, 75870 Paris, France, and
| | - Howard T. Jacobs
- the Institute of Medical Technology and Centre for Laboratory Medicine, Tampere University Hospital, FI-33014 University of Tampere, Finland
| | - Cormac T. Taylor
- the Conway Institute for Biomedical and Biochemical Research, University College Dublin 4, Belfield, Dublin D4, Ireland
| | - Thilo Hagen
- From the Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 117597 Singapore
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Brown ST, Buttigieg J, Nurse CA. Divergent roles of reactive oxygen species in the responses of perinatal adrenal chromaffin cells to hypoxic challenges. Respir Physiol Neurobiol 2010; 174:252-8. [PMID: 20804866 DOI: 10.1016/j.resp.2010.08.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2010] [Revised: 08/23/2010] [Accepted: 08/24/2010] [Indexed: 11/28/2022]
Abstract
The fetus and neonate experience variable patterns of low P(O)₂(hypoxia) ranging from acute, sustained, and intermittent. Adaptation to hypoxia involves activation of key transcription factors, known as hypoxia-inducible factors (e.g. HIF-1α, HIF-2α), which regulate a number of genes in different cell types. This review focuses on the signaling pathways that mediate proper physiological responses of perinatal adrenomedullary chromaffin cells (AMC) to varying patterns of hypoxic challenges, and particularly on the controversial role of reactive oxygen species (ROS). At birth, acute hypoxia (seconds to minutes) directly stimulates catecholamine release from AMC via K+ channel inhibition, mediated by a decrease in mitochondrial-derived ROS. By contrast, exposure to chronic sustained hypoxia (CSH) induces HIF-2α in a fetal-derived chromaffin cell line independently of changes in ROS. Exposure to chronic intermittent hypoxia (CIH) activates antioxidant responses via the regulator Nrf-2, in association with an increase in ROS and the induction of HIF-1α. We propose that the physiological responses of perinatal AMC to hypoxia and the ensuing directional changes in ROS are dependent on the pattern and duration of the hypoxic exposure.
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Affiliation(s)
- Stephen T Brown
- Department of Biology, McMaster University, 1280 Main St. West, Hamilton, Ontario, Canada L8S 4K1
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Knowles HJ, Schaefer KL, Dirksen U, Athanasou NA. Hypoxia and hypoglycaemia in Ewing's sarcoma and osteosarcoma: regulation and phenotypic effects of Hypoxia-Inducible Factor. BMC Cancer 2010; 10:372. [PMID: 20637078 PMCID: PMC2918574 DOI: 10.1186/1471-2407-10-372] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Accepted: 07/16/2010] [Indexed: 11/15/2022] Open
Abstract
Background Hypoxia regulates gene expression via the transcription factor HIF (Hypoxia-Inducible Factor). Little is known regarding HIF expression and function in primary bone sarcomas. We describe HIF expression and phenotypic effects of hypoxia, hypoglycaemia and HIF in Ewing's sarcoma and osteosarcoma. Methods HIF-1α and HIF-2α immunohistochemistry was performed on a Ewing's tumour tissue array. Ewing's sarcoma and osteosarcoma cell lines were assessed for HIF pathway induction by Western blot, luciferase assay and ELISA. Effects of hypoxia, hypoglycaemia and isoform-specific HIF siRNA were assessed on proliferation, apoptosis and migration. Results 17/56 Ewing's tumours were HIF-1α-positive, 15 HIF-2α-positive and 10 positive for HIF-1α and HIF-2α. Expression of HIF-1α and cleaved caspase 3 localised to necrotic areas. Hypoxia induced HIF-1α and HIF-2α in Ewing's and osteosarcoma cell lines while hypoglycaemia specifically induced HIF-2α in Ewing's. Downstream transcription was HIF-1α-dependent in Ewing's sarcoma, but regulated by both isoforms in osteosarcoma. In both cell types hypoglycaemia reduced cellular proliferation by ≥ 45%, hypoxia increased apoptosis and HIF siRNA modulated hypoxic proliferation and migration. Conclusions Co-localisation of HIF-1α and necrosis in Ewing's sarcoma suggests a role for hypoxia and/or hypoglycaemia in in vivo induction of HIF. In vitro data implicates hypoxia as the primary HIF stimulus in both Ewing's and osteosarcoma, driving effects on proliferation and apoptosis. These results provide a foundation from which to advance understanding of HIF function in the pathobiology of primary bone sarcomas.
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Affiliation(s)
- Helen J Knowles
- Botnar Research Centre, University of Oxford, Nuffield Orthopaedic Centre, Oxford, OX3 7LD, UK.
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Activation of hypoxia inducible factor 1 is a general phenomenon in infections with human pathogens. PLoS One 2010; 5:e11576. [PMID: 20644645 PMCID: PMC2904385 DOI: 10.1371/journal.pone.0011576] [Citation(s) in RCA: 131] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Accepted: 06/10/2010] [Indexed: 11/18/2022] Open
Abstract
Background Hypoxia inducible factor (HIF)-1 is the key transcriptional factor involved in the adaptation process of cells and organisms to hypoxia. Recent findings suggest that HIF-1 plays also a crucial role in inflammatory and infectious diseases. Methodology/Principal Findings Using patient skin biopsies, cell culture and murine infection models, HIF-1 activation was determined by immunohistochemistry, immunoblotting and reporter gene assays and was linked to cellular oxygen consumption. The course of a S. aureus peritonitis was determined upon pharmacological HIF-1 inhibition. Activation of HIF-1 was detectable (i) in all ex vivo in biopsies of patients suffering from skin infections, (ii) in vitro using cell culture infection models and (iii) in vivo using murine intravenous and peritoneal S. aureus infection models. HIF-1 activation by human pathogens was induced by oxygen-dependent mechanisms. Small colony variants (SCVs) of S. aureus known to cause chronic infections did not result in cellular hypoxia nor in HIF-1 activation. Pharmaceutical inhibition of HIF-1 activation resulted in increased survival rates of mice suffering from a S. aureus peritonitis. Conclusions/Significance Activation of HIF-1 is a general phenomenon in infections with human pathogenic bacteria, viruses, fungi and protozoa. HIF-1-regulated pathways might be an attractive target to modulate the course of life-threatening infections.
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Anokhina EB, Buravkova LB. Mechanisms of regulation of transcription factor HIF under hypoxia. BIOCHEMISTRY (MOSCOW) 2010; 75:151-8. [DOI: 10.1134/s0006297910020057] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Dehne N, Hintereder G, Brüne B. High glucose concentrations attenuate hypoxia-inducible factor-1alpha expression and signaling in non-tumor cells. Exp Cell Res 2010; 316:1179-89. [PMID: 20184881 DOI: 10.1016/j.yexcr.2010.02.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Revised: 01/15/2010] [Accepted: 02/16/2010] [Indexed: 10/19/2022]
Abstract
Hypoxia-inducible factor (HIF) is the major transcription factor mediating adaption to hypoxia e.g. by enhancing glycolysis. In tumor cells, high glucose concentrations are known to increase HIF-1alpha expression even under normoxia, presumably by enhancing the concentration of tricarboxylic acid cycle intermediates, while reactions of non-tumor cells are not well defined. Therefore, we analyzed cellular responses to different glucose concentrations in respect to HIF activation comparing tumor to non-tumor cells. Using cells derived from non-tumor origin, we show that HIF-1alpha accumulation was higher under low compared to high glucose concentrations. Low glucose allowed mRNA expression of HIF-1 target genes like adrenomedullin. Transfection of C(2)C(12) cells with a HIF-1alpha oxygen-dependent degradation domaine-GFP fusion protein revealed that prolyl hydroxylase (PHD) activity is impaired at low glucose concentrations, thus stabilizing the fusion protein. Mechanistic considerations suggested that neither O(2) redistribution nor an altered redox state explains impaired PHD activity in the absence of glucose. In order to affect PHD activity, glucose needs to be metabolized. Amino acids present in the medium also diminished HIF-1alpha expression, while the addition of fatty acids did not. This suggests that glucose or amino acid metabolism increases oxoglutarate concentrations, which enhances PHD activity in non-tumor cells. Tumor cells deprived of glutamine showed HIF-1alpha accumulation in the absence of glucose, proposing that enhanced glutaminolysis observed in many tumors enables these cells to compensate reduced oxoglutarate production in the absence of glucose.
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Affiliation(s)
- Nathalie Dehne
- Institute of Biochemistry I/ZAFES, Frankfurt am Main, Germany.
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Abstract
Tumour hypoxia is a well-known microenvironmental factor that causes cancer progression and resistance to cancer treatment. This involves multiple mechanisms of which the best-understood ones are mediated through transcriptional gene activation by the hypoxia-inducible factors (HIFs). HIFs in turn are regulated in response to oxygen availability by a family of iron- and 2-oxoglutarate-dependent dioxygenases, the HIF prolyl hydroxylases (PHDs). PHDs inactivate HIFs in normoxia by activating degradation of the HIF-α subunit but release HIF activation in poorly oxygenated conditions. The function of HIF in tumours is fairly well characterized but our understanding on the outcome of PHDs in tumours is much more limited. Here we review the function of PHDs on the HIF system, the expression of PHDs in human tumours as well as their putative function in cancer. The PHDs may have either tumour promoting or suppressing activity. Their outcome in cancer depends on the cell and cancer type-specific expression and on the availability of diverse natural PHD inhibitors in tumours. Moreover, besides the action of PHDs on HIF, recent data suggest PHD function in non-HIF signalling. Together the data illustrate a complex operation of the oxygen sensors in cancer.
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Affiliation(s)
- Terhi Jokilehto
- Turku Centre for Biotechnology, University of Turku and Abo Akademi University, Turku, Finland
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