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Kumar S, Arora R, Gupta S, Ahuja N, Bhagyaraj E, Nanduri R, Kalra R, Khare AK, Kumawat S, Kaushal V, Sharma M, Gupta P. Nuclear receptor Rev-erbα role in fine-tuning erythropoietin gene expression. Blood Adv 2024; 8:3705-3717. [PMID: 38748870 PMCID: PMC11296239 DOI: 10.1182/bloodadvances.2023012228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 05/08/2024] [Indexed: 07/13/2024] Open
Abstract
ABSTRACT The regulation of red blood cell (RBC) homeostasis by erythropoietin (EPO) is critical for O2 transport and maintaining the adequate number of RBCs in vertebrates. Therefore, dysregulation in EPO synthesis results in disease conditions such as polycythemia in the case of excessive EPO production and anemia, which occurs when EPO is inadequately produced. EPO plays a crucial role in treating anemic patients; however, its overproduction can increase blood viscosity, potentially leading to fatal heart failure. Consequently, the identification of druggable transcription factors and their associated ligands capable of regulating EPO offers a promising therapeutic approach to address EPO-related disorders. This study unveils a novel regulatory mechanism involving 2 pivotal nuclear receptors (NRs), Rev-ERBA (Rev-erbα, is a truncation of reverse c-erbAa) and RAR-related orphan receptor A (RORα), in the control of EPO gene expression. Rev-erbα acts as a cell-intrinsic negative regulator, playing a vital role in maintaining erythropoiesis at the correct level. It accomplishes this by directly binding to newly identified response elements within the human and mouse EPO gene promoter, thereby repressing EPO production. These findings are further supported by the discovery that a Rev-erbα agonist (SR9011) effectively suppresses hypoxia-induced EPO expression in mice. In contrast, RORα functions as a positive regulator of EPO gene expression, also binding to the same response elements in the promoter to induce EPO production. Finally, the results of this study revealed that the 2 NRs, Rev-erbα and RORα, influence EPO synthesis in a negative and positive manner, respectively, suggesting that the modulating activity of these 2 NRs could provide a method to target disorders linked with EPO dysregulation.
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Affiliation(s)
- Sumit Kumar
- Department of Molecular Biology, CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Rashmi Arora
- Department of Molecular Biology, CSIR-Institute of Microbial Technology, Chandigarh, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, India
| | - Shalini Gupta
- Department of Molecular Biology, CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Nancy Ahuja
- Department of Molecular Biology, CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Ella Bhagyaraj
- Department of Molecular Biology, CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Ravikanth Nanduri
- Department of Molecular Biology, CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Rashi Kalra
- Department of Molecular Biology, CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Asheesh Kumar Khare
- Department of Molecular Biology, CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Saumyata Kumawat
- Department of Molecular Biology, CSIR-Institute of Microbial Technology, Chandigarh, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, India
| | - Vipashu Kaushal
- Department of Molecular Biology, CSIR-Institute of Microbial Technology, Chandigarh, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, India
| | - Mahathi Sharma
- Department of Molecular Biology, CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Pawan Gupta
- Department of Molecular Biology, CSIR-Institute of Microbial Technology, Chandigarh, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, India
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Collier H, Albanese A, Kwok CS, Kou J, Rocha S. Functional crosstalk between chromatin and hypoxia signalling. Cell Signal 2023; 106:110660. [PMID: 36990334 DOI: 10.1016/j.cellsig.2023.110660] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/18/2023] [Accepted: 03/23/2023] [Indexed: 03/29/2023]
Abstract
Eukaryotic genomes are organised in a structure called chromatin, comprising of DNA and histone proteins. Chromatin is thus a fundamental regulator of gene expression, as it offers storage and protection but also controls accessibility to DNA. Sensing and responding to reductions in oxygen availability (hypoxia) have recognised importance in both physiological and pathological processes in multicellular organisms. One of the main mechanisms controlling these responses is control of gene expression. Recent findings in the field of hypoxia have highlighted how oxygen and chromatin are intricately linked. This review will focus on mechanisms controlling chromatin in hypoxia, including chromatin regulators such as histone modifications and chromatin remodellers. It will also highlight how these are integrated with hypoxia inducible factors and the knowledge gaps that persist.
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Affiliation(s)
- Harry Collier
- Institute of Systems Molecular and Integrative Biology, University of Liverpool, United Kingdom
| | - Adam Albanese
- Institute of Systems Molecular and Integrative Biology, University of Liverpool, United Kingdom
| | - Chun-Sui Kwok
- Institute of Systems Molecular and Integrative Biology, University of Liverpool, United Kingdom
| | - Jiahua Kou
- Institute of Systems Molecular and Integrative Biology, University of Liverpool, United Kingdom
| | - Sonia Rocha
- Institute of Systems Molecular and Integrative Biology, University of Liverpool, United Kingdom.
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3
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El-Kashef DH, Youssef ME, Nasr M, Alrouji M, Alhajlah S, AlOmeir O, El Adle Khalaf N, Ghaffar DMA, Jamil L, Abdel-Nasser ZM, Ibrahim S, Abdeldaiem MSI, Donia SS, Mohammed OA, Morsy NE, Shata A, Saber S. Pimitespib, an HSP90 inhibitor, augments nifuroxazide-induced disruption in the IL-6/STAT3/HIF-1α autocrine loop in rats with bleomycin-challenged lungs: Evolutionary perspective in managing pulmonary fibrosis. Biomed Pharmacother 2022; 153:113487. [DOI: 10.1016/j.biopha.2022.113487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 07/15/2022] [Accepted: 07/27/2022] [Indexed: 11/02/2022] Open
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Devaux CA, Raoult D. The impact of COVID-19 on populations living at high altitude: Role of hypoxia-inducible factors (HIFs) signaling pathway in SARS-CoV-2 infection and replication. Front Physiol 2022; 13:960308. [PMID: 36091390 PMCID: PMC9454615 DOI: 10.3389/fphys.2022.960308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 08/02/2022] [Indexed: 11/13/2022] Open
Abstract
Cases of coronavirus disease 2019 (COVID-19) have been reported worldwide. However, one epidemiological report has claimed a lower incidence of the disease in people living at high altitude (>2,500 m), proposing the hypothesis that adaptation to hypoxia may prove to be advantageous with respect to SARS-CoV-2 infection. This publication was initially greeted with skepticism, because social, genetic, or environmental parametric variables could underlie a difference in susceptibility to the virus for people living in chronic hypobaric hypoxia atmospheres. Moreover, in some patients positive for SARS-CoV-2, early post-infection ‘happy hypoxia” requires immediate ventilation, since it is associated with poor clinical outcome. If, however, we accept to consider the hypothesis according to which the adaptation to hypoxia may prove to be advantageous with respect to SARS-CoV-2 infection, identification of the molecular rational behind it is needed. Among several possibilities, HIF-1 regulation appears to be a molecular hub from which different signaling pathways linking hypoxia and COVID-19 are controlled. Interestingly, HIF-1α was reported to inhibit the infection of lung cells by SARS-CoV-2 by reducing ACE2 viral receptor expression. Moreover, an association of the rs11549465 variant of HIF-1α with COVID-19 susceptibility was recently discovered. Here, we review the evidence for a link between HIF-1α, ACE2 and AT1R expression, and the incidence/severity of COVID-19. We highlight the central role played by the HIF-1α signaling pathway in the pathophysiology of COVID-19.
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Affiliation(s)
- Christian Albert Devaux
- Aix-Marseille University, IRD, APHM, MEPHI, Marseille, France
- IHU-Méditerranée Infection, Marseille, France
- Centre National de la Recherche Scientifique, Marseille, France
- *Correspondence: Christian Albert Devaux,
| | - Didier Raoult
- Aix-Marseille University, IRD, APHM, MEPHI, Marseille, France
- IHU-Méditerranée Infection, Marseille, France
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SRC-3 Knockout Attenuates Myocardial Injury Induced by Chronic Intermittent Hypoxia in Mice. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:6372430. [PMID: 34777690 PMCID: PMC8580638 DOI: 10.1155/2021/6372430] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 10/03/2021] [Accepted: 10/13/2021] [Indexed: 12/30/2022]
Abstract
This study investigated the effects of chronic intermittent hypoxia (CIH), a model of sleep apnea syndrome (SAS), on cardiac function. SRC-3 was extremely lowly expressed in the adult mouse heart tissue, while SRC-3 was highly expressed in the adult mouse heart tissue after CIH, suggesting that SRC-3 is involved in CIH model. We further studied the role of SRC-3 in CIH-induced myocardial injury in mice. Twenty-four healthy Balb/c male mice (n = 16, wild type; n = 8, SRC-3 knockout (SRC3-KO)) were randomly divided into three groups: air control (Ctrl), CIH, and CIH+SRC3-KO. Mice were exposed to CIH for 12 weeks. qRT-PCR was used to evaluate cardiac expression of the following genes: 11HSD1, 11HSD2, GR, MR, COX-2, OPN, NOX2, HIF-1-α, IL-1β, IL-6, iNOS, TNF-α, PC-1, and TGF-β. Enzymatic levels of SOD, CAT, MDA, NOS, and NO in the mouse hearts were determined using commercially available kits. Immunohistochemistry (IHC) was used to evaluate NF-κB expression in cardiac tissues. A transmission electron microscope (TEM) was used to evaluate myocardial ultrastructure. TUNEL staining was used to assess myocardial cell apoptosis. CIH induced cardiac damage, which was ameliorated in the SRC-3 KO mice. CIH significantly increased the heart-to-body weight ratio, expression of all aforementioned genes except 11HSD1, GR, and MR, and increased the levels of MDA, NOS, NO, and NF-κB, which were attenuated in the SRC-3 KO mice. The CIH group had the lowest SOD and CAT levels, which were partially recovered in the CIH+SRC3-KO group. 11HSD2 gene expression was elevated in both the CIH and CIH+SRC3-KO groups compared to the Ctrl group. The CIH group had severe myocardial cell apoptosis and mitochondrial dysfunction, which were alleviated in the CIH+SRC3-KO group. CIH causes cardiac damage through inducing oxidative stress and inflammation. Knockout of SRC-3 ameliorates CIH-induced cardiac damage through antagonizing CIH-triggered molecular changes in cardiac tissue.
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Tomc J, Debeljak N. Molecular Pathways Involved in the Development of Congenital Erythrocytosis. Genes (Basel) 2021; 12:1150. [PMID: 34440324 PMCID: PMC8391844 DOI: 10.3390/genes12081150] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/24/2021] [Accepted: 07/26/2021] [Indexed: 01/08/2023] Open
Abstract
Patients with idiopathic erythrocytosis are directed to targeted genetic testing including nine genes involved in oxygen sensing pathway in kidneys, erythropoietin signal transduction in pre-erythrocytes and hemoglobin-oxygen affinity regulation in mature erythrocytes. However, in more than 60% of cases the genetic cause remains undiagnosed, suggesting that other genes and mechanisms must be involved in the disease development. This review aims to explore additional molecular mechanisms in recognized erythrocytosis pathways and propose new pathways associated with this rare hematological disorder. For this purpose, a comprehensive review of the literature was performed and different in silico tools were used. We identified genes involved in several mechanisms and molecular pathways, including mRNA transcriptional regulation, post-translational modifications, membrane transport, regulation of signal transduction, glucose metabolism and iron homeostasis, which have the potential to influence the main erythrocytosis-associated pathways. We provide valuable theoretical information for deeper insight into possible mechanisms of disease development. This information can be also helpful to improve the current diagnostic solutions for patients with idiopathic erythrocytosis.
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Affiliation(s)
| | - Nataša Debeljak
- Medical Centre for Molecular Biology, Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, SI-1000 Ljubljana, Slovenia;
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7
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Weinhouse C. The roles of inducible chromatin and transcriptional memory in cellular defense system responses to redox-active pollutants. Free Radic Biol Med 2021; 170:85-108. [PMID: 33789123 PMCID: PMC8382302 DOI: 10.1016/j.freeradbiomed.2021.03.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 03/12/2021] [Accepted: 03/15/2021] [Indexed: 12/17/2022]
Abstract
People are exposed to wide range of redox-active environmental pollutants. Air pollution, heavy metals, pesticides, and endocrine disrupting chemicals can disrupt cellular redox status. Redox-active pollutants in our environment all trigger their own sets of specific cellular responses, but they also activate a common set of general stress responses that buffer the cell against homeostatic insults. These cellular defense system (CDS) pathways include the heat shock response, the oxidative stress response, the hypoxia response, the unfolded protein response, the DNA damage response, and the general stress response mediated by the stress-activated p38 mitogen-activated protein kinase. Over the past two decades, the field of environmental epigenetics has investigated epigenetic responses to environmental pollutants, including redox-active pollutants. Studies of these responses highlight the role of chromatin modifications in controlling the transcriptional response to pollutants and the role of transcriptional memory, often referred to as "epigenetic reprogramming", in predisposing previously exposed individuals to more potent transcriptional responses on secondary challenge. My central thesis in this review is that high dose or chronic exposure to redox-active pollutants leads to transcriptional memories at CDS target genes that influence the cell's ability to mount protective responses. To support this thesis, I will: (1) summarize the known chromatin features required for inducible gene activation; (2) review the known forms of transcriptional memory; (3) discuss the roles of inducible chromatin and transcriptional memory in CDS responses that are activated by redox-active environmental pollutants; and (4) propose a conceptual framework for CDS pathway responsiveness as a readout of total cellular exposure to redox-active pollutants.
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Affiliation(s)
- Caren Weinhouse
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, 97214, USA.
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8
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Tomc J, Debeljak N. Molecular Insights into the Oxygen-Sensing Pathway and Erythropoietin Expression Regulation in Erythropoiesis. Int J Mol Sci 2021; 22:ijms22137074. [PMID: 34209205 PMCID: PMC8269393 DOI: 10.3390/ijms22137074] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/25/2021] [Accepted: 06/26/2021] [Indexed: 02/07/2023] Open
Abstract
Erythropoiesis is regulated by several factors, including the oxygen-sensing pathway as the main regulator of erythropoietin (EPO) synthesis in the kidney. The release of EPO from the kidney and its binding to the EPO receptor (EPOR) on erythrocyte progenitor cells in the bone marrow results in increased erythropoiesis. Any imbalance in these homeostatic mechanisms can lead to dysregulated erythropoiesis and hematological disorders. For example, mutations in genes encoding key players of oxygen-sensing pathway and regulation of EPO production (HIF-EPO pathway), namely VHL, EGLN, EPAS1 and EPO, are well known causative factors that contribute to the development of erythrocytosis. We aimed to investigate additional molecular mechanisms involved in the HIF-EPO pathway that correlate with erythropoiesis. To this end, we conducted an extensive literature search and used several in silico tools. We identified genes encoding transcription factors and proteins that control transcriptional activation or repression; genes encoding kinases, deacetylases, methyltransferases, conjugating enzymes, protein ligases, and proteases involved in post-translational modifications; and genes encoding nuclear transport receptors that regulate nuclear transport. All these genes may modulate the stability or activity of HIF2α and its partners in the HIF-EPO pathway, thus affecting EPO synthesis. The theoretical information we provide in this work can be a valuable tool for a better understanding of one of the most important regulatory pathways in the process of erythropoiesis. This knowledge is necessary to discover the causative factors that may contribute to the development of hematological diseases and improve current diagnostic and treatment solutions in this regard.
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Affiliation(s)
- Jana Tomc
- Medical Centre for Molecular Biology, Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia;
- Centre for Functional Genomics and Bio-Chips, Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Nataša Debeljak
- Medical Centre for Molecular Biology, Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia;
- Correspondence: ; Tel.: +386-1-543-7645
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9
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Hussain I, Deb P, Chini A, Obaid M, Bhan A, Ansari KI, Mishra BP, Bobzean SA, Udden SMN, Alluri PG, Das HK, Brothers RM, Perrotti LI, Mandal SS. HOXA5 Expression Is Elevated in Breast Cancer and Is Transcriptionally Regulated by Estradiol. Front Genet 2021; 11:592436. [PMID: 33384715 PMCID: PMC7770181 DOI: 10.3389/fgene.2020.592436] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 10/26/2020] [Indexed: 12/12/2022] Open
Abstract
HOXA5 is a homeobox-containing gene associated with the development of the lung, gastrointestinal tract, and vertebrae. Here, we investigate potential roles and the gene regulatory mechanism in HOXA5 in breast cancer cells. Our studies demonstrate that HOXA5 expression is elevated in breast cancer tissues and in estrogen receptor (ER)-positive breast cancer cells. HOXA5 expression is critical for breast cancer cell viability. Biochemical studies show that estradiol (E2) regulates HOXA5 gene expression in cultured breast cancer cells in vitro. HOXA5 expression is also upregulated in vivo in the mammary tissues of ovariectomized female rats. E2-induced HOXA5 expression is coordinated by ERs. Knockdown of either ERα or ERβ downregulated E2-induced HOXA5 expression. Additionally, ER co-regulators, including CBP/p300 (histone acetylases) and MLL-histone methylases (MLL2, MLL3), histone acetylation-, and H3K4 trimethylation levels are enriched at the HOXA5 promoter in present E2. In summary, our studies demonstrate that HOXA5 is overexpressed in breast cancer and is transcriptionally regulated via estradiol in breast cancer cells.
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Affiliation(s)
- Imran Hussain
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, United States
| | - Paromita Deb
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, United States
| | - Avisankar Chini
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, United States
| | - Monira Obaid
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, United States
| | - Arunoday Bhan
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, United States
| | - Khairul I Ansari
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, United States
| | - Bibhu P Mishra
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, United States
| | - Samara A Bobzean
- Department of Psychology, The University of Texas at Arlington, Arlington, TX, United States
| | - S M Nashir Udden
- Department of Radiation Oncology, The University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Prasanna G Alluri
- Department of Radiation Oncology, The University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Hriday K Das
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Institute for Healthy Aging, Fort Worth, TX, United States
| | - Robert Matthew Brothers
- Department of Kinesiology, The University of Texas at Arlington, Arlington, TX, United States
| | - Linda I Perrotti
- Department of Psychology, The University of Texas at Arlington, Arlington, TX, United States
| | - Subhrangsu S Mandal
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, United States
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10
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Kindrick JD, Mole DR. Hypoxic Regulation of Gene Transcription and Chromatin: Cause and Effect. Int J Mol Sci 2020; 21:E8320. [PMID: 33171917 PMCID: PMC7664190 DOI: 10.3390/ijms21218320] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 10/30/2020] [Accepted: 10/31/2020] [Indexed: 12/11/2022] Open
Abstract
Cellular responses to low oxygen (hypoxia) are fundamental to normal physiology and to the pathology of many common diseases. Hypoxia-inducible factor (HIF) is central to this by enhancing the transcriptional activity of many hundreds of genes. The cellular response to HIF is cell-type-specific and is largely governed by the pre-existing epigenetic landscape. Prior to activation, HIF-binding sites and the promoters of HIF-target genes are already accessible, in contact with each other through chromatin looping and display markers of activity. However, hypoxia also modulates the epigenetic environment, both in parallel to and as a consequence of HIF activation. This occurs through a combination of oxygen-sensitive changes in enzyme activity, transcriptional activation of epigenetic modifiers, and localized recruitment to chromatin by HIF and activated RNApol2. These hypoxic changes in the chromatin environment may both contribute to and occur as a consequence of transcriptional regulation. Nevertheless, they have the capacity to both modulate and extend the transcriptional response to hypoxia.
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Affiliation(s)
| | - David R. Mole
- NDM Research Building, Nuffield Department of Medicine, University of Oxford, Roosevelt Drive, Headington, Oxford OX3 7FZ, UK;
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11
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Vetrovoy OV, Glushchenko TS, Sarieva KV, Tyulkova EI, Aramisova RM, Samoilov MO. The Acetylation of Histone H3 at Lys24 Is Accompanied by Delayed Expression of Neuroprotective Proteins Bcl-2 and BDNF in the Neocortex of Rats Exposed to Severe Hypoxia: the Effect of Postconditioning. NEUROCHEM J+ 2018. [DOI: 10.1134/s1819712418030157] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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12
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Luo W, Wang Y. Epigenetic regulators: multifunctional proteins modulating hypoxia-inducible factor-α protein stability and activity. Cell Mol Life Sci 2018; 75:1043-1056. [PMID: 29032501 PMCID: PMC5984203 DOI: 10.1007/s00018-017-2684-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 09/26/2017] [Accepted: 10/09/2017] [Indexed: 12/19/2022]
Abstract
The hypoxia-inducible factor (HIF) is a heterodimeric transcription factor governing a transcriptional program in response to reduced O2 availability in metazoans. It contributes to physiology and pathogenesis of many human diseases through its downstream target genes. Emerging studies have shown that the transcriptional activity of HIF is highly regulated at multiple levels and the epigenetic regulators are essential for HIF-mediated transactivation. In this review, we will discuss the comprehensive regulation of HIF transcriptional activity by different types of epigenetic regulators.
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Affiliation(s)
- Weibo Luo
- Department of Pathology, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX, 75390, USA.
- Department of Pharmacology, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX, 75390, USA.
| | - Yingfei Wang
- Department of Pathology, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX, 75390, USA.
- Department of Neurology and Neurotherapeutics, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX, 75390, USA.
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13
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Labrecque MP, Takhar MK, Nason R, Santacruz S, Tam KJ, Massah S, Haegert A, Bell RH, Altamirano-Dimas M, Collins CC, Lee FJS, Prefontaine GG, Cox ME, Beischlag TV. The retinoblastoma protein regulates hypoxia-inducible genetic programs, tumor cell invasiveness and neuroendocrine differentiation in prostate cancer cells. Oncotarget 2018; 7:24284-302. [PMID: 27015368 PMCID: PMC5029701 DOI: 10.18632/oncotarget.8301] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 03/04/2016] [Indexed: 12/14/2022] Open
Abstract
Loss of tumor suppressor proteins, such as the retinoblastoma protein (Rb), results in tumor progression and metastasis. Metastasis is facilitated by low oxygen availability within the tumor that is detected by hypoxia inducible factors (HIFs). The HIF1 complex, HIF1α and dimerization partner the aryl hydrocarbon receptor nuclear translocator (ARNT), is the master regulator of the hypoxic response. Previously, we demonstrated that Rb represses the transcriptional response to hypoxia by virtue of its association with HIF1. In this report, we further characterized the role Rb plays in mediating hypoxia-regulated genetic programs by stably ablating Rb expression with retrovirally-introduced short hairpin RNA in LNCaP and 22Rv1 human prostate cancer cells. DNA microarray analysis revealed that loss of Rb in conjunction with hypoxia leads to aberrant expression of hypoxia-regulated genetic programs that increase cell invasion and promote neuroendocrine differentiation. For the first time, we have established a direct link between hypoxic tumor environments, Rb inactivation and progression to late stage metastatic neuroendocrine prostate cancer. Understanding the molecular pathways responsible for progression of benign prostate tumors to metastasized and lethal forms will aid in the development of more effective prostate cancer therapies.
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Affiliation(s)
- Mark P Labrecque
- The Faculty of Health Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Mandeep K Takhar
- The Faculty of Health Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Rebecca Nason
- The Faculty of Health Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Stephanie Santacruz
- The Faculty of Health Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Kevin J Tam
- The Faculty of Health Sciences, Simon Fraser University, Burnaby, British Columbia, Canada.,Department of Urologic Sciences, The Vancouver Prostate Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Shabnam Massah
- The Faculty of Health Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Anne Haegert
- Department of Urologic Sciences, The Vancouver Prostate Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Robert H Bell
- Department of Urologic Sciences, The Vancouver Prostate Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Manuel Altamirano-Dimas
- Department of Urologic Sciences, The Vancouver Prostate Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Colin C Collins
- Department of Urologic Sciences, The Vancouver Prostate Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Frank J S Lee
- The Faculty of Health Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Gratien G Prefontaine
- The Faculty of Health Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Michael E Cox
- Department of Urologic Sciences, The Vancouver Prostate Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Timothy V Beischlag
- The Faculty of Health Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
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Samoilov MO, Churilova AV, Glushchenko TS, Rybnikova EA. The influence of different types of hypobaric hypoxia on histone H3 methylation in rat neocortical and hippocampal neurons. NEUROCHEM J+ 2017. [DOI: 10.1134/s1819712417020106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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15
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Samoilov M, Churilova A, Gluschenko T, Vetrovoy O, Dyuzhikova N, Rybnikova E. Acetylation of histones in neocortex and hippocampus of rats exposed to different modes of hypobaric hypoxia: Implications for brain hypoxic injury and tolerance. Acta Histochem 2016; 118:80-9. [PMID: 26643215 DOI: 10.1016/j.acthis.2015.11.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 11/14/2015] [Accepted: 11/16/2015] [Indexed: 12/26/2022]
Abstract
Acetylation of nucleosome histones results in relaxation of DNA and its availability for the transcriptional regulators, and is generally associated with the enhancement of gene expression. Although it is well known that activation of a variety of pro-adaptive genes represents a key event in the development of brain hypoxic/ischemic tolerance, the role of epigenetic mechanisms, in particular histone acetylation, in this process is still unexplored. The aim of the present study was to investigate changes in acetylation of histones in vulnerable brain neurons using original well-standardized model of hypobaric hypoxia and preconditioning-induced tolerance of the brain. Using quantitative immunohistochemistry and Western blot, effects of severe injurious hypobaric hypoxia (SH, 180mm Hg, 3h) and neuroprotective preconditioning mode (three episodes of 360mm Hg for 2h spaced at 24h) on the levels of the acetylated proteins and acetylated H3 Lys24 (H3K24ac) in the neocortex and hippocampus of rats were studied. SH caused global repression of the acetylation processes in the neocortex (layers II-III, V) and hippocampus (CA1, CA3) by 3-24h, and this effect was prevented by the preconditioning. Moreover, hypoxic preconditioning remarkably increased the acetylation of H3K24 in response to SH in the brain areas examined. The preconditioning hypoxia without subsequent SH also stimulated acetylation processes in the neocortex and hippocampus. The moderately enhanced expression of the acetylated proteins in the preconditioned rats was maintained for 24h, whereas acetylation of H3K24 was intense but transient, peaked at 3h. The novel data obtained in the present study indicate that large activation of the acetylation processes, in particular acetylation of histones might be essential for the development of brain hypoxic tolerance.
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Affiliation(s)
- Mikhail Samoilov
- Laboratory of Regulation of Brain Neuron Functions, Pavlov Institute of Physiology, Russian Academy of Sciences, Makarova nab. 6, 199034 St. Petersburg, Russian Federation
| | - Anna Churilova
- Laboratory of Regulation of Brain Neuron Functions, Pavlov Institute of Physiology, Russian Academy of Sciences, Makarova nab. 6, 199034 St. Petersburg, Russian Federation
| | - Tatjana Gluschenko
- Laboratory of Regulation of Brain Neuron Functions, Pavlov Institute of Physiology, Russian Academy of Sciences, Makarova nab. 6, 199034 St. Petersburg, Russian Federation
| | - Oleg Vetrovoy
- Laboratory of Regulation of Brain Neuron Functions, Pavlov Institute of Physiology, Russian Academy of Sciences, Makarova nab. 6, 199034 St. Petersburg, Russian Federation; Department of Biochemistry, Faculty of Biology, St. Petersburg State University, 7-9, Universitetskaya nab., 199034 St. Petersburg, Russian Federation
| | - Natalia Dyuzhikova
- Laboratory of Genetics of High Nervous Activity, Pavlov Institute of Physiology, Russian Academy of Sciences, Makarova nab. 6, 199034 St. Petersburg, Russian Federation
| | - Elena Rybnikova
- Laboratory of Neuroendocrinology, Pavlov Institute of Physiology, Russian Academy of Sciences, Makarova nab. 6, 199034 St. Petersburg, Russian Federation.
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Tsai CH, Li CH, Liao PL, Cheng YW, Lin CH, Huang SH, Kang JJ. NcoA2-Dependent Inhibition of HIF-1α Activation Is Regulated via AhR. Toxicol Sci 2015; 148:517-30. [PMID: 26350169 DOI: 10.1093/toxsci/kfv199] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
High endogenous levels of aryl hydrocarbon receptor (AhR) contribute to hypoxia signaling pathway inhibition following exposure to the potent AhR ligand benzo[a]pyrene (B[a]P) and could alter cellular homeostasis and disease condition. Increasing evidence indicates that AhR might compete with AhR nuclear translocator (ARNT) for complex formation with hypoxia-inducible factor-1α (HIF-1α) for transactivation, which could alter several physiological variables. Nuclear receptor coactivator 2 (NcoA2) is a transcription coactivator that regulates transcription factor activation and inhibition of basic helix-loop-helix Per (Period)-ARNT-SIM (single-minded) (bHLH-PAS) family proteins, such as HIF-1α, ARNT, and AhR, through protein-protein interactions. In this study, we demonstrated that both hypoxia and hypoxia-mimic conditions decreased NcoA2 protein expression in HEK293T cells. Hypoxia response element (HRE) and xenobiotic-responsive element (XRE) transactivation also were downregulated with NcoA2 knockdown under hypoxic conditions. In addition, B[a]P significantly decreased NcoA2 protein expression be accompanied with AhR degradation. We next evaluated whether the absence of AhR could affect NcoA2 protein function under hypoxia-mimetic conditions. NcoA2 and HIF-1α nuclear localization decreased in both B[a]P-pretreated and AhR-knockdown HepG2 cells under hypoxia-mimic conditions. Interestingly, NcoA2 overexpression downregulated HRE transactivation by competing with HIF-1α and AhR to form protein complexes with ARNT. Both NcoA2 knockdown and overexpression inhibited endothelial cell tube formation in vitro. We also demonstrated using the in vivo plug assay that NcoA2-regulated vascularization decreased in mice. Taken together, these results revealed a biphasic role of NcoA2 between AhR and hypoxic conditions, thus providing a novel mechanism underlying the cross talk between AhR and hypoxia that affects disease development and progression.
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Affiliation(s)
- Chi-Hao Tsai
- *Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ching-Hao Li
- Department of Physiology, School of Medicine; Graduate Institute of Medical Sciences, College of Medicine, and
| | - Po-Lin Liao
- *Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan; School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei, Taiwan
| | - Yu-Wen Cheng
- School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei, Taiwan
| | - Cheng-Hui Lin
- School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei, Taiwan
| | - Shih-Hsuan Huang
- School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei, Taiwan
| | - Jaw-Jou Kang
- *Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan;
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Chen D, Yang Y, Cheng X, Fang F, Xu G, Yuan Z, Xia J, Kong H, Xie W, Wang H, Fang M, Gao Y, Xu Y. Megakaryocytic Leukemia 1 Directs a Histone H3 Lysine 4 Methyltransferase Complex to Regulate Hypoxic Pulmonary Hypertension. Hypertension 2015; 65:821-33. [DOI: 10.1161/hypertensionaha.114.04585] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Dewei Chen
- From the Department of Pathophysiology and High Altitude Physiology, College of High Altitude Military Medicine (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of High Altitude Medicine, Ministry of Education (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of High Altitude Medicine, PLA, Third Military Medical University (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of Cardiovascular Disease and Department of Pathophysiology (Y.Y., X.C., F.F., M.F., Y.X.), and Department of Respiratory Medicine, the
| | - Yuyu Yang
- From the Department of Pathophysiology and High Altitude Physiology, College of High Altitude Military Medicine (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of High Altitude Medicine, Ministry of Education (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of High Altitude Medicine, PLA, Third Military Medical University (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of Cardiovascular Disease and Department of Pathophysiology (Y.Y., X.C., F.F., M.F., Y.X.), and Department of Respiratory Medicine, the
| | - Xian Cheng
- From the Department of Pathophysiology and High Altitude Physiology, College of High Altitude Military Medicine (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of High Altitude Medicine, Ministry of Education (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of High Altitude Medicine, PLA, Third Military Medical University (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of Cardiovascular Disease and Department of Pathophysiology (Y.Y., X.C., F.F., M.F., Y.X.), and Department of Respiratory Medicine, the
| | - Fei Fang
- From the Department of Pathophysiology and High Altitude Physiology, College of High Altitude Military Medicine (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of High Altitude Medicine, Ministry of Education (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of High Altitude Medicine, PLA, Third Military Medical University (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of Cardiovascular Disease and Department of Pathophysiology (Y.Y., X.C., F.F., M.F., Y.X.), and Department of Respiratory Medicine, the
| | - Gang Xu
- From the Department of Pathophysiology and High Altitude Physiology, College of High Altitude Military Medicine (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of High Altitude Medicine, Ministry of Education (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of High Altitude Medicine, PLA, Third Military Medical University (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of Cardiovascular Disease and Department of Pathophysiology (Y.Y., X.C., F.F., M.F., Y.X.), and Department of Respiratory Medicine, the
| | - Zhibin Yuan
- From the Department of Pathophysiology and High Altitude Physiology, College of High Altitude Military Medicine (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of High Altitude Medicine, Ministry of Education (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of High Altitude Medicine, PLA, Third Military Medical University (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of Cardiovascular Disease and Department of Pathophysiology (Y.Y., X.C., F.F., M.F., Y.X.), and Department of Respiratory Medicine, the
| | - Jun Xia
- From the Department of Pathophysiology and High Altitude Physiology, College of High Altitude Military Medicine (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of High Altitude Medicine, Ministry of Education (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of High Altitude Medicine, PLA, Third Military Medical University (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of Cardiovascular Disease and Department of Pathophysiology (Y.Y., X.C., F.F., M.F., Y.X.), and Department of Respiratory Medicine, the
| | - Hui Kong
- From the Department of Pathophysiology and High Altitude Physiology, College of High Altitude Military Medicine (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of High Altitude Medicine, Ministry of Education (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of High Altitude Medicine, PLA, Third Military Medical University (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of Cardiovascular Disease and Department of Pathophysiology (Y.Y., X.C., F.F., M.F., Y.X.), and Department of Respiratory Medicine, the
| | - Weiping Xie
- From the Department of Pathophysiology and High Altitude Physiology, College of High Altitude Military Medicine (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of High Altitude Medicine, Ministry of Education (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of High Altitude Medicine, PLA, Third Military Medical University (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of Cardiovascular Disease and Department of Pathophysiology (Y.Y., X.C., F.F., M.F., Y.X.), and Department of Respiratory Medicine, the
| | - Hong Wang
- From the Department of Pathophysiology and High Altitude Physiology, College of High Altitude Military Medicine (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of High Altitude Medicine, Ministry of Education (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of High Altitude Medicine, PLA, Third Military Medical University (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of Cardiovascular Disease and Department of Pathophysiology (Y.Y., X.C., F.F., M.F., Y.X.), and Department of Respiratory Medicine, the
| | - Mingming Fang
- From the Department of Pathophysiology and High Altitude Physiology, College of High Altitude Military Medicine (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of High Altitude Medicine, Ministry of Education (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of High Altitude Medicine, PLA, Third Military Medical University (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of Cardiovascular Disease and Department of Pathophysiology (Y.Y., X.C., F.F., M.F., Y.X.), and Department of Respiratory Medicine, the
| | - Yuqi Gao
- From the Department of Pathophysiology and High Altitude Physiology, College of High Altitude Military Medicine (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of High Altitude Medicine, Ministry of Education (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of High Altitude Medicine, PLA, Third Military Medical University (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of Cardiovascular Disease and Department of Pathophysiology (Y.Y., X.C., F.F., M.F., Y.X.), and Department of Respiratory Medicine, the
| | - Yong Xu
- From the Department of Pathophysiology and High Altitude Physiology, College of High Altitude Military Medicine (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of High Altitude Medicine, Ministry of Education (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of High Altitude Medicine, PLA, Third Military Medical University (D.C., G.X., Z.Y., Y.G., Y.X.), Key Laboratory of Cardiovascular Disease and Department of Pathophysiology (Y.Y., X.C., F.F., M.F., Y.X.), and Department of Respiratory Medicine, the
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18
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Nangaku M, Mimura I, Yamaguchi J, Higashijima Y, Wada T, Tanaka T. Role of uremic toxins in erythropoiesis-stimulating agent resistance in chronic kidney disease and dialysis patients. J Ren Nutr 2014; 25:160-3. [PMID: 25556149 DOI: 10.1053/j.jrn.2014.10.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 10/29/2014] [Indexed: 11/11/2022] Open
Abstract
Patients with advanced chronic kidney disease are exposed to uremic toxins. In addition to causing uremic symptoms, uremic toxins accelerate the progression of renal failure. Indoxyl sulfate (IS) increases oxygen consumption in tubules, aggravating hypoxia of the kidney, and progression of the kidney disease. IS also induces endoplasmic reticulum stress and thereby contributes the progression of cellular damages in tubular epithelial cells. Hypoxia-inducible factor (HIF) is a master transcriptional regulator of adaptive responses against hypoxia and regulates expression of erythropoietin (EPO). IS suppresses EPO expression via HIF-dependent and HIF-independent manner. IS impedes the recruitment of transcriptional coactivators to HIF via upregulation of Cbp/p300-interacting transactivator with Glu/Asp-rich carboxy-terminal domain 2 through a mechanism of posttranscriptional messenger RNA stabilization. Furthermore, IS induces activating transcription factor 4 via endoplasmic reticulum stress, decreasing EPO expression. Although erythropoiesis-stimulating agent (ESA) resistance is generally defined as lack of responses to exogenous ESA administration, suppression of endogenous production of EPO under uremic conditions may aggravate ESA resistance. Uremia is associated with increased formation of advanced glycation end products (AGE). Studies of transgenic rats overexpressing glyoxalse 1 (GLO1), which detoxifies precursors of advanced glycation end products, demonstrated that glycative stress causes renal senescence and vascular endothelial dysfunction. Glycative stress also suppresses HIF activation making the kidney susceptible to hypoxia as a final common pathway to end-stage kidney disease.
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Affiliation(s)
- Masaomi Nangaku
- Division of Nephrology and Endocrinology, The University of Tokyo Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan.
| | - Imari Mimura
- Division of Nephrology and Endocrinology, The University of Tokyo Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan
| | - Junna Yamaguchi
- Division of Nephrology and Endocrinology, The University of Tokyo Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan
| | - Yoshiki Higashijima
- Division of Nephrology and Endocrinology, The University of Tokyo Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan
| | - Takehiko Wada
- Division of Nephrology and Endocrinology, The University of Tokyo Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan
| | - Tetsuhiro Tanaka
- Division of Nephrology and Endocrinology, The University of Tokyo Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan
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19
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Abstract
Mammalian basic HLH (helix-loop-helix)-PER-ARNT-SIM (bHLH-PAS) proteins are heterodimeric transcription factors that sense and respond to environmental signals (such as pollutants) or to physiological signals (for example, hypoxia and circadian rhythms) through their two PAS domains. PAS domains form a generic three-dimensional fold, which commonly contains an internal cavity capable of small-molecule binding and outer surfaces adept at protein-protein interactions. These proteins are important in several pro-tumour and antitumour pathways and their activities can be modulated by both natural metabolites and oncometabolites. Recently determined structures and successful small-molecule screening programmes are now providing new opportunities to discover selective agonists and antagonists directed against this multitasking family of transcription factors.
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Affiliation(s)
- David C Bersten
- School of Molecular and Biomedical Science (Biochemistry) and the Centre for Molecular Pathology, University of Adelaide, South Australia 5005, Australia
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20
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Dengler VL, Galbraith M, Espinosa JM. Transcriptional regulation by hypoxia inducible factors. Crit Rev Biochem Mol Biol 2013; 49:1-15. [PMID: 24099156 DOI: 10.3109/10409238.2013.838205] [Citation(s) in RCA: 525] [Impact Index Per Article: 47.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The cellular response to oxygen deprivation is governed largely by a family of transcription factors known as Hypoxia Inducible Factors (HIFs). This review focuses on the molecular mechanisms by which HIFs regulate the transcriptional apparatus to enable the cellular and organismal response to hypoxia. We discuss here how the various HIF polypeptides, their posttranslational modifications, binding partners and transcriptional cofactors affect RNA polymerase II activity to drive context-dependent transcriptional programs during hypoxia.
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Affiliation(s)
- Veronica L Dengler
- Howard Hughes Medical Institute & Department of Molecular, Cellular and Developmental Biology, The University of Colorado at Boulder, Boulder, CO 80309-0347, U.S.A
| | - Matthew Galbraith
- Howard Hughes Medical Institute & Department of Molecular, Cellular and Developmental Biology, The University of Colorado at Boulder, Boulder, CO 80309-0347, U.S.A
| | - Joaquín M Espinosa
- Howard Hughes Medical Institute & Department of Molecular, Cellular and Developmental Biology, The University of Colorado at Boulder, Boulder, CO 80309-0347, U.S.A
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BRG1 and BRM chromatin-remodeling complexes regulate the hypoxia response by acting as coactivators for a subset of hypoxia-inducible transcription factor target genes. Mol Cell Biol 2013; 33:3849-63. [PMID: 23897427 DOI: 10.1128/mcb.00731-13] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Chromatin remodeling is an active process, which represses or enables the access of transcription machinery to genes in response to external stimuli, including hypoxia. However, in hypoxia, the specific requirement, as well as the molecular mechanism by which the chromatin-remodeling complexes regulate gene expression, remains unclear. In this study, we report that the Brahma (BRM) and Brahma-related gene 1 (BRG1) ATPase-containing SWI/SNF chromatin-remodeling complexes promote the expression of the hypoxia-inducible transcription factor 1α (HIF1α) and HIF2α genes and also promote hypoxic induction of a subset of HIF1 and HIF2 target genes. We show that BRG1 or BRM knockdown in Hep3B and RCC4T cells reduces hypoxic induction of HIF target genes, while reexpression of BRG1 or BRM in BRG1/BRM-deficient SW13 cells increases HIF target gene activation. Mechanistically, HIF1 and HIF2 increase the hypoxic induction of HIF target genes by recruiting BRG1 complexes to HIF target gene promoters, which promotes nucleosome remodeling of HIF target gene promoters in a BRG1 ATPase-dependent manner. Importantly, we found that the function of BRG1 complexes in hypoxic SW13 and RCC4T cells is dictated by the HIF-mediated hypoxia response and could be opposite from their function in normoxic SW13 and RCC4T cells.
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Tsai YP, Wu KJ. Epigenetic regulation of hypoxia-responsive gene expression: focusing on chromatin and DNA modifications. Int J Cancer 2013; 134:249-56. [PMID: 23564219 DOI: 10.1002/ijc.28190] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 03/28/2013] [Indexed: 12/20/2022]
Abstract
Mammalian cells constantly encounter hypoxia, which is a stress condition occurring during development and physiological processes. To adapt to this inevitable condition, cells develop various mechanisms to cope with this stress and survive. In addition to the activation/stabilization of transcriptional regulators (hypoxia-inducible factors), other epigenetic mechanisms of gene regulation are used. These mechanisms are mediated by various players including transcriptional coregulators, chromatin-modifying complexes, histone modification enzymes and changes in DNA methylation status. Recent progress in all the fields mentioned above has greatly improved the knowledge of how gene regulation contributes to the hypoxic response. This review should shed light on the molecular epigenetic mechanisms of hypoxia-induced gene regulation and help understand the processes adapted by cells to cope with hypoxia.
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Affiliation(s)
- Ya-Ping Tsai
- Institute of Biochemistry & Molecular Biology, National Yang-Ming University, Taipei, Taiwan
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23
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Safronova OS. Post-translational modifications of proteins in gene regulation under hypoxic conditions. Inflamm Regen 2013. [DOI: 10.2492/inflammregen.33.203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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Chiang CK, Nangaku M, Tanaka T, Iwawaki T, Inagi R. Endoplasmic reticulum stress signal impairs erythropoietin production: a role for ATF4. Am J Physiol Cell Physiol 2012; 304:C342-53. [PMID: 23242184 DOI: 10.1152/ajpcell.00153.2012] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hypoxia upregulates the hypoxia-inducible factor (HIF) pathway and the endoplasmic reticulum (ER) stress signal, unfolded protein response (UPR). The cross talk of both signals affects the pathogenic alteration by hypoxia. Here we showed that ER stress induced by tunicamycin or thapsigargin suppressed inducible (CoCl(2) or hypoxia) transcription of erythropoietin (EPO), a representative HIF target gene, in HepG2. This suppression was inversely correlated with UPR activation, as estimated by expression of the UPR regulator glucose-regulated protein 78, and restored by an ER stress inhibitor, salubrinal, in association with normalization of the UPR state. Importantly, the decreased EPO expression was also observed in HepG2 overexpressing UPR activating transcription factor (ATF)4. Overexpression of mutated ATF4 that lacks the transcriptional activity did not alter EPO transcriptional regulation. Transcriptional activity of the EPO 3'-enhancer, which is mainly regulated by HIF, was abolished by both ER stressors and ATF4 overexpression, while nuclear HIF accumulation or expression of other HIF target genes was not suppressed by ER stress. Chromatin immunoprecipitation analysis identified a novel ATF4 binding site (TGACCTCT) within the EPO 3'-enhancer region, suggesting a distinct role for ATF4 in UPR-dependent suppression of the enhancer. Induction of ER stress in rat liver and kidney by tunicamycin decreased the hepatic and renal mRNA and plasma level of EPO. Collectively, ER stress selectively impairs the transcriptional activity of EPO but not of other HIF target genes. This effect is mediated by suppression of EPO 3'-enhancer activity via ATF4 without any direct effect on HIF, indicating that UPR contributes to oxygen-sensing regulation of EPO.
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Affiliation(s)
- Chih-Kang Chiang
- Division of Nephrology and Endocrinology, University of Tokyo School of Medicine, Tokyo, Japan
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25
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The growing complexity of HIF-1α’s role in tumorigenesis: DNA repair and beyond. Oncogene 2012; 32:3569-76. [DOI: 10.1038/onc.2012.510] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 09/28/2012] [Accepted: 09/27/2012] [Indexed: 12/13/2022]
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Srivastava M, Khurana P, Sugadev R. Lung cancer signature biomarkers: tissue specific semantic similarity based clustering of digital differential display (DDD) data. BMC Res Notes 2012; 5:617. [PMID: 23122428 PMCID: PMC3532198 DOI: 10.1186/1756-0500-5-617] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 10/23/2012] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND The tissue-specific Unigene Sets derived from more than one million expressed sequence tags (ESTs) in the NCBI, GenBank database offers a platform for identifying significantly and differentially expressed tissue-specific genes by in-silico methods. Digital differential display (DDD) rapidly creates transcription profiles based on EST comparisons and numerically calculates, as a fraction of the pool of ESTs, the relative sequence abundance of known and novel genes. However, the process of identifying the most likely tissue for a specific disease in which to search for candidate genes from the pool of differentially expressed genes remains difficult. Therefore, we have used 'Gene Ontology semantic similarity score' to measure the GO similarity between gene products of lung tissue-specific candidate genes from control (normal) and disease (cancer) sets. This semantic similarity score matrix based on hierarchical clustering represents in the form of a dendrogram. The dendrogram cluster stability was assessed by multiple bootstrapping. Multiple bootstrapping also computes a p-value for each cluster and corrects the bias of the bootstrap probability. RESULTS Subsequent hierarchical clustering by the multiple bootstrapping method (α = 0.95) identified seven clusters. The comparative, as well as subtractive, approach revealed a set of 38 biomarkers comprising four distinct lung cancer signature biomarker clusters (panel 1-4). Further gene enrichment analysis of the four panels revealed that each panel represents a set of lung cancer linked metastasis diagnostic biomarkers (panel 1), chemotherapy/drug resistance biomarkers (panel 2), hypoxia regulated biomarkers (panel 3) and lung extra cellular matrix biomarkers (panel 4). CONCLUSIONS Expression analysis reveals that hypoxia induced lung cancer related biomarkers (panel 3), HIF and its modulating proteins (TGM2, CSNK1A1, CTNNA1, NAMPT/Visfatin, TNFRSF1A, ETS1, SRC-1, FN1, APLP2, DMBT1/SAG, AIB1 and AZIN1) are significantly down regulated. All down regulated genes in this panel were highly up regulated in most other types of cancers. These panels of proteins may represent signature biomarkers for lung cancer and will aid in lung cancer diagnosis and disease monitoring as well as in the prediction of responses to therapeutics.
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Affiliation(s)
- Mousami Srivastava
- Bioinformatics Group, Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, Delhi-110054, India
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27
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Craig EA, Weber JD, Spiegelman VS. Involvement of the mRNA binding protein CRD-BP in the regulation of metastatic melanoma cell proliferation and invasion by hypoxia. J Cell Sci 2012; 125:5950-4. [PMID: 23038779 DOI: 10.1242/jcs.115204] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
We have previously shown that the mRNA binding protein CRD-BP is overexpressed in human melanomas, where it promotes cell survival and resistance to chemotherapy. The present study investigates the role of hypoxia, a common characteristic of the tumor microenvironment, in the regulation of CRD-BP expression and melanoma cell responses. We found that hypoxia increases CRD-BP levels in metastatic melanoma cell lines but not in melanocytes or primary melanoma cells. Hypoxic stimulation transcriptionally regulates CRD-BP by facilitating the acetylation of histones within the CRD-BP gene and by modulating the extent of HIF1α binding to the CRD-BP promoter. Hypoxia significantly enhances the proliferative and invasive potential of metastatic melanoma cells but not that of normal or primary melanoma cells. Furthermore, inhibition of CRD-BP impairs the ability of metastatic cells to proliferate and invade in response to hypoxia. These findings identify CRD-BP as a novel effector of hypoxic responses that is relevant for the selection of metastatic cells. This work also describes a previously unknown role for CRD-BP in the regulation of melanoma cell invasion and highlights the importance of the hypoxic microenvironment in determining cell fate.
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Affiliation(s)
- Evisabel A Craig
- Department of Dermatology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
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Chen R, Xu M, Hogg RT, Li J, Little B, Gerard RD, Garcia JA. The acetylase/deacetylase couple CREB-binding protein/Sirtuin 1 controls hypoxia-inducible factor 2 signaling. J Biol Chem 2012; 287:30800-11. [PMID: 22807441 DOI: 10.1074/jbc.m111.244780] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Hypoxia-inducible factors (HIFs) are oxygen-sensitive transcription factors. HIF-1α plays a prominent role in hypoxic gene induction. HIF-2α target genes are more restricted but include erythropoietin (Epo), one of the most highly hypoxia-inducible genes in mammals. We previously reported that HIF-2α is acetylated during hypoxia but is rapidly deacetylated by the stress-responsive deacetylase Sirtuin 1. We now demonstrate that the lysine acetyltransferases cAMP-response element-binding protein-binding protein (CBP) and p300 are required for efficient Epo induction during hypoxia. However, despite close structural similarity, the roles of CBP and p300 differ in HIF signaling. CBP acetylates HIF-2α, is a major coactivator for HIF-2-mediated Epo induction, and is required for Sirt1 augmentation of HIF-2 signaling during hypoxia in Hep3B cells. In comparison, p300 is a major contributor for HIF-1 signaling as indicated by induction of Pgk1. Whereas CBP can bind with HIF-2α independent of the HIF-2α C-terminal activation domain via enzyme/substrate interactions, p300 only complexes with HIF-2α through the C-terminal activation domain. Maximal CBP/HIF-2 signaling requires intact CBP acetyltransferase activity in both Hep3B cells as well as in mice.
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Affiliation(s)
- Rui Chen
- Department of Medicine, Veterans Affairs North Texas Health Care System, Dallas, TX 75216, USA
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Won Jeong K, Chodankar R, Purcell DJ, Bittencourt D, Stallcup MR. Gene-specific patterns of coregulator requirements by estrogen receptor-α in breast cancer cells. Mol Endocrinol 2012; 26:955-66. [PMID: 22543272 DOI: 10.1210/me.2012-1066] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Progesterone receptor (PgR) controls the menstrual cycle, pregnancy, embryonic development, and homeostasis, and it plays important roles in breast cancer development and progression. However, the requirement of coregulators for estrogen-induced expression of the PgR gene has not been fully explored. Here we used RNA interference to demonstrate dramatic differences in requirements of 10 different coregulators for estrogen-regulated expression of six different genes, including PgR and the well-studied TFF1 (or pS2) gene in MCF-7 breast cancer cells. Full estrogen-induced expression of TFF1 required all ten coregulators, but PgR induction required only four of the 10 coregulators. Chromatin immunoprecipitation studies demonstrated several mechanisms responsible for the differential coregulator requirements. Actin-binding coregulator Flightless-I, required for TFF1 expression and recruited to that gene by estrogen receptor-α (ERα), is not required for PgR expression and not recruited to that gene. Protein acetyltransferase tat-interactive protein 60 and ATP-dependent chromatin remodeler Brahma Related Gene 1 are recruited to both genes but are required only for TFF1 expression. Histone methyltransferase G9a is recruited to both genes and required for estrogen-induced expression of TFF1 but negatively regulates estrogen-induced expression of PgR. In contrast, histone methyltransferase myeloid/lymphoid or mixed-lineage leukemia 1 (MLL1), pioneer factor Forkhead box A1, and p160 coregulator steroid receptor coactivator-3 are required for expression of and are recruited to both genes. Depletion of MLL1 decreased ERα binding to the PgR and TFF1 genes. In contrast, depletion of G9a enhanced ERα binding to the PgR gene but had no effect on ERα binding to the TFF1 gene. These studies suggest that differential promoter architecture is responsible for promoter-specific mechanisms of gene regulation.
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Affiliation(s)
- Kwang Won Jeong
- Department of Biochemistry and Molecular Biology, University of Southern California/Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA 90089, USA
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Wu MY, Fu J, Xu J, O'Malley BW, Wu RC. Steroid receptor coactivator 3 regulates autophagy in breast cancer cells through macrophage migration inhibitory factor. Cell Res 2012; 22:1003-21. [PMID: 22430150 DOI: 10.1038/cr.2012.44] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
SRC-3/AIB1 (steroid receptor coactivator 3/amplified in breast cancer 1) is an authentic oncogene that contributes to the development of drug resistance and poor disease-free survival in cancer patients. Autophagy is also an important cell death mechanism that has tumor suppressor function. In this study, we identified macrophage migration inhibitory factor (MIF) as a novel target gene of SRC-3 and demonstrated its importance in cell survival. Specifically, we showed that MIF is a strong suppressor of autophagic cell death. We further showed that suppression of MIF, in turn, induced autophagic cell death, enhanced chemosensitivity and inhibited tumorigenesis in a xenograft mouse tumorigenesis model. Our study demonstrated that regulation of MIF expression and suppression of autophagic cell death is a potent mechanism by which SRC-3 contributes to increased chemoresistance and tumorigenicity.
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Affiliation(s)
- Mei-Yi Wu
- Department of Biochemistry and Molecular Biology, George Washington University, Washington, DC 20037, USA.
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Melvin A, Rocha S. Chromatin as an oxygen sensor and active player in the hypoxia response. Cell Signal 2012; 24:35-43. [PMID: 21924352 PMCID: PMC3476533 DOI: 10.1016/j.cellsig.2011.08.019] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Accepted: 08/29/2011] [Indexed: 12/28/2022]
Abstract
Changes in the availability or demand for oxygen induce dramatic changes at the cellular level. Primarily, activation of a family of oxygen labile transcription factors, Hypoxia Inducible Factor (HIF), initiates a variety of cellular processes required to re-instate oxygen homeostasis. Oxygen is sensed by molecular dioxygenases in cells, such as the prolyl-hydroxylases (PHDs), enzymes which are responsible for the oxygen-dependent regulation of HIF. As HIF is a transcription factor it must bind DNA sequences of its target genes possibly in the context of a complex chromatin structure. How chromatin structure changes in response to hypoxia is currently unknown. However, the identification of a novel class of histone demethylases as true dioxygenases suggests that chromatin can act as an oxygen sensor and plays an active role in the coordination of the cellular response to hypoxia. This review will discuss the current knowledge on how hypoxia engages with different proteins involved in chromatin organisation and dynamics.
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Key Words
- hif, hypoxia inducible factor
- arnt, aryl hydrocarbon nuclear translocator
- vhl, von hippel lindau
- phd, prolyl-hydroxylase
- fih, factor inhibiting hif
- chip, chromatin immunoprecipitation
- swi/snf, switch/sucrose nonfermentable
- iswi, imitation switch
- chd, chromodomain helicase dna-binding
- nurf, nucleosome remodelling factor
- chrac, chromatin remodelling and assembly complex
- acf, atp-utilising chromatin remodelling and assembly factor
- norc, nucleolar remodelling complex
- rsf, remodelling and spacing factor
- wich, wstf–iswi chromatin remodelling complex
- nurd, nucleosome remodelling and histone deacetylase
- srcap, snf2-related cbp activator protein
- trrap, transformation/transcription domain-associated protein/tip60
- hat, histone acetyl transferase
- hdac, histone deacetylase
- lsd1, lysine-specific demethylase-1
- jmjc, jumonji c domain
- hypoxia
- chromatin
- hif
- transcription
- chromatin remodellers
- jmjc demethylases
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Affiliation(s)
| | - Sonia Rocha
- Wellcome Trust Centre for Gene Regulation and Expression, College of Life Sciences, MSI/WTB/JBC Complex, Dow Street, University of Dundee, Dundee, DD1 5EH, Scotland, United Kingdom
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Erythropoietin promotes survival and regeneration of insect neurons in vivo and in vitro. Neuroscience 2011; 188:95-108. [DOI: 10.1016/j.neuroscience.2011.05.018] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Revised: 05/06/2011] [Accepted: 05/07/2011] [Indexed: 12/11/2022]
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Perez-Perri JI, Acevedo JM, Wappner P. Epigenetics: new questions on the response to hypoxia. Int J Mol Sci 2011; 12:4705-21. [PMID: 21845106 PMCID: PMC3155379 DOI: 10.3390/ijms12074705] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 07/08/2011] [Accepted: 07/08/2011] [Indexed: 12/16/2022] Open
Abstract
Reduction in oxygen levels below normal concentrations plays important roles in different normal and pathological conditions, such as development, tumorigenesis, chronic kidney disease and stroke. Organisms exposed to hypoxia trigger changes at both cellular and systemic levels to recover oxygen homeostasis. Most of these processes are mediated by Hypoxia Inducible Factors, HIFs, a family of transcription factors that directly induce the expression of several hundred genes in mammalian cells. Although different aspects of HIF regulation are well known, it is still unclear by which precise mechanism HIFs activate transcription of their target genes. Concomitantly, hypoxia provokes a dramatic decrease of general transcription that seems to rely in part on epigenetic changes through a poorly understood mechanism. In this review we discuss the current knowledge on chromatin changes involved in HIF dependent gene activation, as well as on other epigenetic changes, not necessarily linked to HIF that take place under hypoxic conditions.
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Affiliation(s)
- Joel I. Perez-Perri
- Instituto Leloir, Patricias Argentinas 435, Buenos Aires C1405BWE, Argentina; E-Mails: (J.I.P.-P.); (J.M.A.)
- Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires C1033AAJ, Argentina
| | - Julieta M. Acevedo
- Instituto Leloir, Patricias Argentinas 435, Buenos Aires C1405BWE, Argentina; E-Mails: (J.I.P.-P.); (J.M.A.)
- Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires C1033AAJ, Argentina
| | - Pablo Wappner
- Instituto Leloir, Patricias Argentinas 435, Buenos Aires C1405BWE, Argentina; E-Mails: (J.I.P.-P.); (J.M.A.)
- Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires C1033AAJ, Argentina
- Facultad de Ciencias Exactas y Naturales (FCEyN), Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +54-11-5238-7500 ext.3112; Fax: +54-11-5238-7501
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Abstract
The hormone erythropoietin (Epo) maintains red blood cell mass by promoting the survival, proliferation and differentiation of erythrocytic progenitors. Circulating Epo originates mainly from fibroblasts in the renal cortex. Epo production is controlled at the transcriptional level. Hypoxia attenuates the inhibition of the Epo promoter by GATA-2. More importantly, hypoxia promotes the availability of heterodimeric (α/β) hypoxia-inducible transcription factors (predominantly HIF-2) which stimulate the Epo enhancer. The HIFs are inactivated in normoxia by enzymatic hydroxylation of their α-subunits. Three HIF-α prolyl hydroxylases (PHD-1, -2 and -3) initiate proteasomal degradation of HIF-α, while an asparaginyl hydroxylase ('factor inhibiting HIF-1', FIH-1) inhibits the transactivation potential. The HIF-α hydroxylases contain Fe(2+) and require 2-oxoglutarate as co-factor. The in vivo response is dynamic, i.e. the concentration of circulating Epo increases initially greatly following an anaemic or hypoxaemic stimulus and then declines despite continued hypoxia. Epo and angiotensin II collaborate in the maintenance of the blood volume. Whether extra-renal sites (brain, skin) modulate renal Epo production is a matter of debate. Epo overproduction results in erythrocytosis. Epo deficiency is the primary cause of the anaemia in chronic kidney disease and a contributing factor in the anaemias of chronic inflammation and cancer. Here, recombinant analogues can substitute for the hormone.
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Affiliation(s)
- Wolfgang Jelkmann
- Institute of Physiology, University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany.
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