1
|
Kim Y, Koh JS, Woo SD, Lee SI, Kang DH, Park D, Chung C, Kwon IS, Lee JE. The Tri-iodothyronine (T3) Level Is a Prognostic Factor for Patients With Advanced NSCLC: Receiving Immune Checkpoint Inhibitors and Is Associated With Liver Metastasis. Clin Med Insights Oncol 2022; 16:11795549221139522. [PMID: 36532699 PMCID: PMC9751177 DOI: 10.1177/11795549221139522] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 11/01/2022] [Indexed: 08/22/2023] Open
Abstract
BACKGROUND Endocrine hormones influence tumor progression and the response to treatment. Despite the importance of immune checkpoint inhibitors (ICIs) as treatments for advanced non-small cell lung cancer (NSCLC), few studies have explored the effects of hormone levels in NSCLC patients on the effectiveness of ICI therapies. We thus investigated the effects of baseline blood markers in patients with advanced NSCLC on ICI treatments. METHODS Patients with advanced NSCLC who received programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) inhibitors at Chungnam National University Hospital between December 2016 and November 2020 and who lacked any history of thyroid gland-related diseases were analyzed retrospectively. We collected clinical information and baseline laboratory data, including the levels of endocrine hormones, cytokines, complete blood counts (CBCs), and peripheral blood chemistry panels. We explored the relationships of hormone levels with clinical outcomes (overall survival [OS], progression-free survival [PFS], and best response), liver metastasis, and blood markers using the Kaplan-Meier method, Cox's proportional hazards regression, and logistic regression. RESULTS A total of 113 patients were enrolled. A shorter PFS was independently associated with liver metastasis, higher cortisol levels, and lower hemoglobin (Hb) levels; a shorter OS was associated with liver metastasis, lower tri-iodothyronine (T3) levels, higher lactate dehydrogenase (LDH) levels, and lower albumin levels. Patients with low T3 levels exhibited a shorter PFS and OS, and a poorer best response. Patients with low T3 levels tended to have higher disease progression rates, lower levels of adrenocorticotropic hormone (ACTH), C-peptide, albumin, Hb, and neutrophil-to-lymphocyte ratio, and higher levels of interleukin (IL)-6, white blood cells, platelets, compared with those with normal T3 levels. We found a significant association between a low T3 level and liver metastasis. CONCLUSIONS We found the baseline T3 level was associated with both prognosis and the response to ICIs in patients with advanced NSCLC, probably reflecting impaired liver function and systemic inflammation induced by the interaction of T3 with other biomarkers, such as IL-6, ACTH, cortisol, C-peptide, Hb, LDH, and albumin.
Collapse
Affiliation(s)
- Yoonjoo Kim
- Division of Pulmonology, Department of Internal Medicine, College of Medicine, Chungnam National University, Daejeon, Republic of Korea
| | - Jeong Suk Koh
- Division of Pulmonology, Department of Internal Medicine, College of Medicine, Chungnam National University, Daejeon, Republic of Korea
| | - Seong-Dae Woo
- Division of Pulmonology, Department of Internal Medicine, College of Medicine, Chungnam National University, Daejeon, Republic of Korea
| | - Song-I Lee
- Division of Pulmonology, Department of Internal Medicine, College of Medicine, Chungnam National University, Daejeon, Republic of Korea
| | - Da Hyun Kang
- Division of Pulmonology, Department of Internal Medicine, College of Medicine, Chungnam National University, Daejeon, Republic of Korea
| | - Dongil Park
- Division of Pulmonology, Department of Internal Medicine, College of Medicine, Chungnam National University, Daejeon, Republic of Korea
| | - Chaeuk Chung
- Division of Pulmonology, Department of Internal Medicine, College of Medicine, Chungnam National University, Daejeon, Republic of Korea
| | - In-Sun Kwon
- Clinical Trials Center, Chungnam National University Hospital, Daejeon, Republic of Korea
| | - Jeong Eun Lee
- Division of Pulmonology, Department of Internal Medicine, College of Medicine, Chungnam National University, Daejeon, Republic of Korea
| |
Collapse
|
2
|
Nishie A, Ushijima Y, Takayama Y, Fujita N, Kubo Y, Ishimatsu K, Tsurumaru D, Kohjima M, Ishigami K. Hemodynamic Alteration in the Liver in Acute Hepatitis: A Quantitative Evaluation Using Computed Tomographic Perfusion. In Vivo 2021; 35:3537-3545. [PMID: 34697192 DOI: 10.21873/invivo.12656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 09/29/2021] [Accepted: 09/30/2021] [Indexed: 11/10/2022]
Abstract
BACKGROUND/AIM We aimed to elucidate the hemodynamic alterations in the liver of patients with acute hepatitis (AH) using computed tomography perfusion imaging. PATIENTS AND METHODS For 14 patients with AH and nine patients with no disease (ND group), we compared the mean arterial blood flow (AF), portal blood flow (PF) and perfusion index (%) [PI=AF/(AF+PF) ×100] of the right and left liver lobes and investigated their relationship with clinical factors. RESULTS The mean PI of the right lobe in the AH group (30.5±10.0%) was significantly higher than that in the ND group (20.8±9.7%) (p=0.031). For all patients of the AH and ND groups, the PI of the right lobe was increased as the prothrombin time decreased (R=-0.56, p=0.006) and as the prothrombin time-international normalized ratio increased (R=0.48, p=0.02). CONCLUSION The PI of the right liver lobe may increase in AH and may be a predictive parameter for the severity of hepatic failure.
Collapse
Affiliation(s)
- Akihiro Nishie
- Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, Okinawa, Japan; .,Department of Advanced Imaging and Interventional Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yasuhiro Ushijima
- Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yukihisa Takayama
- Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Nobuhiro Fujita
- Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yuichiro Kubo
- Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Keisuke Ishimatsu
- Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Daisuke Tsurumaru
- Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Motoyuki Kohjima
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Kousei Ishigami
- Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| |
Collapse
|
3
|
|
4
|
Manibalan S, Shobana A, Kiruthika M, Achary A, Swathi M, Venkatalakshmi R, Thirukumaran K, Suhasini K, Roopathy S. Protein Network Studies on PCOS Biomarkers With S100A8, Druggability Assessment, and RNA Aptamer Designing to Control Its Cyst Migration Effect. Front Bioeng Biotechnol 2020; 8:328. [PMID: 32478041 PMCID: PMC7238949 DOI: 10.3389/fbioe.2020.00328] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 03/25/2020] [Indexed: 12/23/2022] Open
Abstract
The prevalence of polycystic ovary syndrome (PCOS) has been gradually increasing among adult females worldwide. Laparoscopy drilling on ovary is the only available temporary solution with a high incidence of reoccurrence. S100A8 with S100A9 complex is believed to facilitate the cyst migration in PCOS condition. The high evident protein interaction network studies between PCOS biomarkers, cancer invasion markers, and the interactors of S100A8 confirm that this protein has strong interaction with other selective PCOS biomarkers, which may be associative in the immature cyst invasion process. Through the network studies, intensive structural and pathway analysis, S100A8 is identified as a targetable protein. In this research, the non-SELEX in silico method is adapted to construct RNA Library based on the consensus DNA sequence of Glucocorticoid Response Element (GRE) and screened the best nucleotide fragments which are bound within the active sites of the target protein. Selected sequences are joined as a single strand and screened the one which competitively binds with minimal energy. In vitro follow-up of this computational research, the designed RNA aptamer was used to infect the MCF7 cell line through Lipofectamine 2000 mediated delivery to study the anti-cell migration effect. Wound Scratch assay confirms that the synthesized 18-mer oligo has significant inhibition activity toward tumor cell migration at the cellular level.
Collapse
Affiliation(s)
| | - Ayyachamy Shobana
- Centre for Research, Kamaraj College of Engineering and Technology, Madurai, India
| | - Manickam Kiruthika
- Centre for Research, Kamaraj College of Engineering and Technology, Madurai, India
| | - Anant Achary
- Centre for Research, Kamaraj College of Engineering and Technology, Madurai, India
| | - Madasamy Swathi
- Centre for Research, Kamaraj College of Engineering and Technology, Madurai, India
| | | | - Kandasamy Thirukumaran
- Department of Biotechnology, Kamaraj College of Engineering and Technology, Madurai, India
| | - K Suhasini
- Department of Biotechnology, Kamaraj College of Engineering and Technology, Madurai, India
| | - Sharon Roopathy
- Department of Biotechnology, Kamaraj College of Engineering and Technology, Madurai, India
| |
Collapse
|
5
|
Rashid I, Pathak AK, Kumar R, Srivastava P, Singh M, Murali S, Kushwaha B. Genome-Wide Comparative Analysis of HIF Binding Sites in Cyprinus Carpio for In Silico Identification of Functional Hypoxia Response Elements. Front Genet 2019; 10:659. [PMID: 31379925 PMCID: PMC6660265 DOI: 10.3389/fgene.2019.00659] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2018] [Accepted: 06/21/2019] [Indexed: 12/20/2022] Open
Abstract
Cyprinus carpio is world's most widely distributed freshwater species highly used in aquaculture. It is a hypoxia-tolerant species as it lives in oxygen-deficient environment for a long period. The tolerance potential of an animal against hypoxia relates it to induced gene expression, where a hypoxia-inducible factor (HIF) binds to a transcriptionally active site, hypoxia response element (HRE), a 5-base short motif that lies within the promoter/enhancer region of a certain gene, for inducing gene expression and preventing/minimizing hypoxia effects. HRE is functionally active when it contains another motif, the hypoxia ancillary sequence (HAS), which is typically adjacent to downstream of HRE within 7- to 15-nt space. Here, an attempt was made for mining HRE and identifying functional HIF binding sites (HBS) in a genome-wide analysis of C. carpio. For this, gene information along with the 5,000-nt upstream (-4,900 to +100) sequences of 31,466 protein coding genes was downloaded from "Gene" and "RefSeq" databases. Analysis was performed after filtration of the impracticable genes. A total of 116,148 HRE consensus sequences were mined from 29,545 genes in different promoter regions. HRE with HAS consensus motifs were found in the promoter region of 9,589 genes. Further, the already reported genes for hypoxia response in humans and zebrafish were reanalyzed for detecting HRE sites in their promoters and used for comparative analysis with gene promoters of C. carpio for providing support to identify functional HBS in the gene promoter of C. carpio. An interactive user interface HREExplorer was developed for presenting the results on the World Wide Web and visualizing possible HBS in protein coding genes in C. carpio and displaying the comparative results along with the reported hypoxia-responsive genes of zebrafish and reported hypoxia-inducible genes in humans. In this study, a set of Perl program was written for the compilation and analysis of information that might be used for a similar study in other species. This novel work may provide a workbench for analyzing the promoter regions of hypoxia-responsive genes.
Collapse
Affiliation(s)
- Iliyas Rashid
- Molecular Biology and Biotechnology Division, ICAR-National Bureau of Fish Genetic Resources, Lucknow, India.,AMITY Institute of Biotechnology, AMITY University Uttar Pradesh, Lucknow, India
| | - Ajey Kumar Pathak
- Molecular Biology and Biotechnology Division, ICAR-National Bureau of Fish Genetic Resources, Lucknow, India
| | - Ravindra Kumar
- Molecular Biology and Biotechnology Division, ICAR-National Bureau of Fish Genetic Resources, Lucknow, India
| | - Prachi Srivastava
- AMITY Institute of Biotechnology, AMITY University Uttar Pradesh, Lucknow, India
| | - Mahender Singh
- Molecular Biology and Biotechnology Division, ICAR-National Bureau of Fish Genetic Resources, Lucknow, India
| | - S Murali
- Molecular Biology and Biotechnology Division, ICAR-National Bureau of Fish Genetic Resources, Lucknow, India
| | - Basdeo Kushwaha
- Molecular Biology and Biotechnology Division, ICAR-National Bureau of Fish Genetic Resources, Lucknow, India
| |
Collapse
|
6
|
Rashid I, Nagpure NS, Srivastava P, Kumar R, Pathak AK, Singh M, Kushwaha B. HRGFish: A database of hypoxia responsive genes in fishes. Sci Rep 2017; 7:42346. [PMID: 28205556 PMCID: PMC5304231 DOI: 10.1038/srep42346] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 01/04/2017] [Indexed: 11/09/2022] Open
Abstract
Several studies have highlighted the changes in the gene expression due to the hypoxia response in fishes, but the systematic organization of the information and the analytical platform for such genes are lacking. In the present study, an attempt was made to develop a database of hypoxia responsive genes in fishes (HRGFish), integrated with analytical tools, using LAMPP technology. Genes reported in hypoxia response for fishes were compiled through literature survey and the database presently covers 818 gene sequences and 35 gene types from 38 fishes. The upstream fragments (3,000 bp), covered in this database, enables to compute CG dinucleotides frequencies, motif finding of the hypoxia response element, identification of CpG island and mapping with the reference promoter of zebrafish. The database also includes functional annotation of genes and provides tools for analyzing sequences and designing primers for selected gene fragments. This may be the first database on the hypoxia response genes in fishes that provides a workbench to the scientific community involved in studying the evolution and ecological adaptation of the fish species in relation to hypoxia.
Collapse
Affiliation(s)
- Iliyas Rashid
- Molecular Biology and Biotechnology Division, ICAR- National Bureau of Fish Genetic Resources, Lucknow- 226002, Uttar Pradesh, India.,AMITY Institute of Biotechnology, AMITY University Uttar Pradesh, Lucknow-226028, Uttar Pradesh, India
| | - Naresh Sahebrao Nagpure
- Fish Genetics and Biotechnology Division, ICAR- Central Institute of Fisheries Education, Mumbai-400 061, Maharashtra, India
| | - Prachi Srivastava
- AMITY Institute of Biotechnology, AMITY University Uttar Pradesh, Lucknow-226028, Uttar Pradesh, India
| | - Ravindra Kumar
- Molecular Biology and Biotechnology Division, ICAR- National Bureau of Fish Genetic Resources, Lucknow- 226002, Uttar Pradesh, India
| | - Ajey Kumar Pathak
- Molecular Biology and Biotechnology Division, ICAR- National Bureau of Fish Genetic Resources, Lucknow- 226002, Uttar Pradesh, India
| | - Mahender Singh
- Molecular Biology and Biotechnology Division, ICAR- National Bureau of Fish Genetic Resources, Lucknow- 226002, Uttar Pradesh, India
| | - Basdeo Kushwaha
- Molecular Biology and Biotechnology Division, ICAR- National Bureau of Fish Genetic Resources, Lucknow- 226002, Uttar Pradesh, India
| |
Collapse
|
7
|
Hermes-Lima M, Moreira DC, Rivera-Ingraham GA, Giraud-Billoud M, Genaro-Mattos TC, Campos ÉG. Preparation for oxidative stress under hypoxia and metabolic depression: Revisiting the proposal two decades later. Free Radic Biol Med 2015; 89:1122-43. [PMID: 26408245 DOI: 10.1016/j.freeradbiomed.2015.07.156] [Citation(s) in RCA: 133] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 07/11/2015] [Accepted: 07/25/2015] [Indexed: 12/22/2022]
Abstract
Organisms that tolerate wide variations in oxygen availability, especially to hypoxia, usually face harsh environmental conditions during their lives. Such conditions include, for example, lack of food and/or water, low or high temperatures, and reduced oxygen availability. In contrast to an expected strong suppression of protein synthesis, a great number of these animals present increased levels of antioxidant defenses during oxygen deprivation. These observations have puzzled researchers for more than 20 years. Initially, two predominant ideas seemed to be irreconcilable: on one hand, hypoxia would decrease reactive oxygen species (ROS) production, while on the other the induction of antioxidant enzymes would require the overproduction of ROS. This induction of antioxidant enzymes during hypoxia was viewed as a way to prepare animals for oxidative damage that may happen ultimately during reoxygenation. The term "preparation for oxidative stress" (POS) was coined in 1998 based on such premise. However, there are many cases of increased oxidative damage in several hypoxia-tolerant organisms under hypoxia. In addition, over the years, the idea of an assured decrease in ROS formation under hypoxia was challenged. Instead, several findings indicate that the production of ROS actually increases in response to hypoxia. Recently, it became possible to provide a comprehensive explanation for the induction of antioxidant enzymes under hypoxia. The supporting evidence and the limitations of the POS idea are extensively explored in this review as we discuss results from research on estivation and situations of low oxygen stress, such as hypoxia, freezing exposure, severe dehydration, and air exposure of water-breathing animals. We propose that, under some level of oxygen deprivation, ROS are overproduced and induce changes leading to hypoxic biochemical responses. These responses would occur mainly through the activation of specific transcription factors (FoxO, Nrf2, HIF-1, NF-κB, and p53) and post translational mechanisms, both mechanisms leading to enhanced antioxidant defenses. Moreover, reactive nitrogen species are candidate modulators of ROS generation in this scenario. We conclude by drawing out the future perspectives in this field of research, and how advances in the knowledge of the mechanisms involved in the POS strategy will offer new and innovative study scenarios of biological and physiological cellular responses to environmental stress.
Collapse
Affiliation(s)
- Marcelo Hermes-Lima
- Laboratório de Radicais Livres, Departamento de Biologia Celular, Universidade de Brasília, Brasí;lia, DF, 70910-900, Brazil.
| | - Daniel C Moreira
- Laboratório de Radicais Livres, Departamento de Biologia Celular, Universidade de Brasília, Brasí;lia, DF, 70910-900, Brazil
| | - Georgina A Rivera-Ingraham
- Groupe Fonctionnel AEO (Adaptation Ecophysiologique et Ontogenèse), UMR 9190 MARBEC, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France
| | - Maximiliano Giraud-Billoud
- Laboratorio de Fisiología (IHEM-CONICET), and Instituto de Fisiología (Facultad de Ciencias Médicas, Universidad Nacional de Cuyo), Casilla de Correo 33, 5500 Mendoza, Argentina
| | - Thiago C Genaro-Mattos
- Laboratório de Radicais Livres, Departamento de Biologia Celular, Universidade de Brasília, Brasí;lia, DF, 70910-900, Brazil; Laboratório de Espectrometria de Massa, Embrapa Recursos Genéticos e Biotecnologia, Brasí;lia, DF, Brazil
| | - Élida G Campos
- Laboratório de Radicais Livres, Departamento de Biologia Celular, Universidade de Brasília, Brasí;lia, DF, 70910-900, Brazil
| |
Collapse
|
8
|
Singh K, Bhori M, Marar T. α-Tocopherol mediated amelioration of camptothecin-induced free radical damage to avert cardiotoxicities. Hum Exp Toxicol 2014; 34:380-9. [PMID: 25304969 DOI: 10.1177/0960327114533577] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Reactive oxygen species (ROS) such as O2(-), hydrogen peroxide, and OH(-) are highly toxic to cells. Cellular antioxidant enzymes and free radical scavengers normally protect a cell from toxic effects of ROS. However, when generation of ROS overtakes the antioxidant defense of the cells, it leads to various pathological conditions. The present study investigated the protective efficacy of α-tocopherol on the peroxidative damage and abnormal antioxidant levels in the myocardial tissue of camptothecin (CPT), administered at the dosage of 6 mg/kg/day in male Wistar rats. CPT-administered rats showed significant increase (p < 0.001) in lipid peroxidation and abnormal changes in the activities/levels of antioxidant enzymes (catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase, glutathione S-transferase) and nonenzymic antioxidants (reduced glutathione and vitamin E). Alterations in the levels of tissue alkaline phosphatase, lactate dehydrogenase (p < 0.01), alanine transaminase (p < 0.001), and aspartate transaminase (p < 0.001) were also observed in CPT-treated rats. In contrast, rats pretreated with α-tocopherol showed significant revision of elevated levels of lipid peroxides and abnormal antioxidant enzyme activity suggesting the ameliorative property of vitamin E. Histopathological alterations in the heart tissue observed after CPT administration were also protected in animals that were pretreated with vitamin E. Based on our results, we conclude that supplementation of vitamin E may improve the efficacy of standard and experimental cancer therapies by subsiding the toxic effect of the antineoplastic agent.
Collapse
Affiliation(s)
- K Singh
- Department of Biotechnology and Bioinformatics, Padmashree Dr. D. Y. Patil University, CBD Belapur, Navi Mumbai, Maharashtra, India.
| | - M Bhori
- Department of Biotechnology and Bioinformatics, Padmashree Dr. D. Y. Patil University, CBD Belapur, Navi Mumbai, Maharashtra, India
| | - T Marar
- Department of Biotechnology and Bioinformatics, Padmashree Dr. D. Y. Patil University, CBD Belapur, Navi Mumbai, Maharashtra, India
| |
Collapse
|
9
|
Cristescu ME, Demiri B, Altshuler I, Crease TJ. Gene expression variation in duplicate lactate dehydrogenase genes: do ecological species show distinct responses? PLoS One 2014; 9:e103964. [PMID: 25080082 PMCID: PMC4117593 DOI: 10.1371/journal.pone.0103964] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 07/09/2014] [Indexed: 11/18/2022] Open
Abstract
Lactate dehydrogenase (LDH) has been shown to play an important role in adaptation of several aquatic species to different habitats. The genomes of Daphnia pulex, a pond species, and Daphnia pulicaria, a lake inhabitant, encode two L-LDH enzymes, LDHA and LDHB. We estimated relative levels of Ldh gene expression in these two closely related species and their hybrids in four environmental settings, each characterized by one of two temperatures (10°C or 20°C), and one of two concentrations of dissolved oxygen (DO; 6.5–7 mg/l or 2–3 mg/l). We found that levels of LdhA expression were 4 to 48 times higher than LdhB expression (p<0.005) in all three groups (the two parental species and hybrids). Moreover, levels of LdhB expression differed significantly (p<0.05) between D. pulex and D. pulicaria, but neither species differed from the hybrid. Consistently higher expression of LdhA relative to LdhB in both species and the hybrid suggests that the two isozymes could be performing different functions. No significant differences in levels of gene expression were observed among the four combinations of temperature and dissolved oxygen (p>0.1). Given that Daphnia dwell in environments characterized by fluctuating conditions with long periods of low dissolved oxygen concentration, we suggest that these species could employ regulated metabolic depression to survive in such environments.
Collapse
Affiliation(s)
- Melania E. Cristescu
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario, Canada
- Department of Biology, McGill University, Montreal, Quebec, Canada
- * E-mail:
| | - Bora Demiri
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario, Canada
| | - Ianina Altshuler
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | - Teresa J. Crease
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| |
Collapse
|
10
|
Thomas P, Rahman MS. Extensive reproductive disruption, ovarian masculinization and aromatase suppression in Atlantic croaker in the northern Gulf of Mexico hypoxic zone. Proc Biol Sci 2012; 279:28-38. [PMID: 21613294 PMCID: PMC3223642 DOI: 10.1098/rspb.2011.0529] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Accepted: 05/04/2011] [Indexed: 12/03/2022] Open
Abstract
The long-term impacts on marine ecosystems of the recent dramatic worldwide increase in the incidence of coastal hypoxia are unknown. Here, we show widespread reproductive disruption in Atlantic croakers collected from hypoxic sites approximately 120 km apart in the extensive northern Gulf of Mexico continental shelf hypoxic zone. Gonadal growth and gamete production were impaired in croakers from hypoxic sites compared with fish from reference normoxic sites east of the Mississippi River Delta. Male germ cells were detected in approximately 19 per cent of croaker ovaries collected in the hypoxic region, but were absent in ovaries from normoxic sites. In addition, the sex ratio was skewed towards males at the hypoxic sites. The masculinization and other reproductive disruptions were associated with declines in neuroendocrine function, as well as ovarian and brain expression of aromatase (the enzyme that converts androgens to oestrogens). A similar incidence of ovarian masculinization and decline in ovarian aromatase expression were observed in croaker after chronic laboratory hypoxia exposure, indicating that ovarian masculinization is a specific hypoxia response and is due to decreased aromatase activity. The results suggest severe reproductive impairment can occur over large coastal regions in marine fish populations exposed to seasonal hypoxia, with potential long-term impacts on population abundance.
Collapse
Affiliation(s)
- Peter Thomas
- The University of Texas at Austin, Marine Science Institute, 750 Channel View Drive, Port Aransas, TX 78373, USA.
| | | |
Collapse
|
11
|
Crease TJ, Floyd R, Cristescu ME, Innes D. Evolutionary factors affecting Lactate dehydrogenase A and B variation in the Daphnia pulex species complex. BMC Evol Biol 2011; 11:212. [PMID: 21767386 PMCID: PMC3231769 DOI: 10.1186/1471-2148-11-212] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Accepted: 07/18/2011] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Evidence for historical, demographic and selective factors affecting enzyme evolution can be obtained by examining nucleotide sequence variation in candidate genes such as Lactate dehydrogenase (Ldh). Two closely related Daphnia species can be distinguished by their electrophoretic Ldh genotype and habitat. Daphnia pulex populations are fixed for the S allele and inhabit temporary ponds, while D. pulicaria populations are fixed for the F allele and inhabit large stratified lakes. One locus is detected in most allozyme surveys, but genome sequencing has revealed two genes, LdhA and LdhB. RESULTS We sequenced both Ldh genes from 70 isolates of these two species from North America to determine if the association between Ldh genotype and habitat shows evidence for selection, and to elucidate the evolutionary history of the two genes. We found that alleles in the pond-dwelling D. pulex and in the lake-dwelling D. pulicaria form distinct groups at both loci, and the substitution of Glutamine (S) for Glutamic acid (F) at amino acid 229 likely causes the electrophoretic mobility shift in the LDHA protein. Nucleotide diversity in both Ldh genes is much lower in D. pulicaria than in D. pulex. Moreover, the lack of spatial structuring of the variation in both genes over a wide geographic area is consistent with a recent demographic expansion of lake populations. Neutrality tests indicate that both genes are under purifying selection, but the intensity is much stronger on LdhA. CONCLUSIONS Although lake-dwelling D. pulicaria hybridizes with the other lineages in the pulex species complex, it remains distinct ecologically and genetically. This ecological divergence, coupled with the intensity of purifying selection on LdhA and the strong association between its genotype and habitat, suggests that experimental studies would be useful to determine if variation in molecular function provides evidence that LDHA variants are adaptive.
Collapse
Affiliation(s)
- Teresa J Crease
- Department of Integrative Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Robin Floyd
- Department of Integrative Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
- School of Clinical Sciences, Southmead Hospital, University of Bristol, Bristol BS105NB, UK
| | - Melania E Cristescu
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario N9B 3P4, Canada
| | - David Innes
- Department of Biology, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador A1B 3X9, Canada
| |
Collapse
|
12
|
Intra- and Inter-specific variation in metabolic gene expression in relationship to environmental hypoxia. Comp Biochem Physiol A Mol Integr Physiol 2011; 159:25-31. [DOI: 10.1016/j.cbpa.2011.01.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 01/12/2011] [Accepted: 01/13/2011] [Indexed: 11/19/2022]
|
13
|
Kotoh K, Kato M, Kohjima M, Nakamuta M, Enjoji M. A new treatment strategy for acute liver failure. World J Hepatol 2010; 2:395-400. [PMID: 21173907 PMCID: PMC3004032 DOI: 10.4254/wjh.v2.i11.395] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2010] [Revised: 10/18/2010] [Accepted: 10/25/2010] [Indexed: 02/06/2023] Open
Abstract
Acute liver failure (ALF) is a syndrome defined by coagulopathy and encephalopathy and no effective treatments have been established, except for liver transplantation. However, considering the limited supply of donors, we should endeavor to prevent the progression of this syndrome in its early stage to improve the prognosis of patients with ALF. Recently, several authors have reported that over-activation of intrahepatic macrophages plays an important role in the progression of ALF and we have developed a new treatment method, transcatheter arterial steroid injection therapy (TASIT), to suppress macrophage activation. We have now used TASIT for 5 years and have found that TASIT is effective for patients with over-activation of macrophages in the liver but not for those with lesser activation of macrophages. Therefore, to identify the most appropriate patients for TASIT, we tried to categorize patients with ALF or acute liver injury according to markers for the degree of intrahepatic macrophage activation. This approach was helpful to select the appropriate treatment including liver transplantation. We believe that it is essential to analyze disease progression in each patient before selecting the most appropriate treatment.
Collapse
Affiliation(s)
- Kazuhiro Kotoh
- Kazuhiro Kotoh, Masaki Kato, Department of Hepatology and Pancreatology, Kyushu University Hospital, Fukuoka 812-8582, Japan
| | | | | | | | | |
Collapse
|
14
|
Soldatov AA, Andreenko TI, Golovina IV, Stolbov AY. Peculiarities of organization of tissue metabolism in molluscs with different tolerance to external hypoxia. J EVOL BIOCHEM PHYS+ 2010. [DOI: 10.1134/s0022093010040022] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
15
|
Ng PKS, Chiu SK, Kwong TFN, Yu RMK, Wong MML, Kong RYC. Functional characterization of two CITED3 homologs (gcCITED3a and gcCITED3b) in the hypoxia-tolerant grass carp, Ctenopharyngodon idellus. BMC Mol Biol 2009; 10:101. [PMID: 19883516 PMCID: PMC2780419 DOI: 10.1186/1471-2199-10-101] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Accepted: 11/03/2009] [Indexed: 11/12/2022] Open
Abstract
Background CITED proteins belong to a family of non-DNA-binding transcriptional co-regulators that are characterized by a conserved ED-rich domain at the C-terminus. This family of genes is involved in the regulation of a variety of transcriptional responses through interactions with the CBP/p300 integrators and various transcription factors. In fish, very little is known about the expression and functions of CITEDs. Results We have characterized two closely related but distinct CITED3 genes, gcCited3a and gcCited3b, from the hypoxia-tolerant grass carp. The deduced gcCITED3a and gcCITED3b proteins share 72% amino acid identity, and are highly similar to the CITED3 proteins of both chicken and Xenopus. Northern blot analysis indicates that the mRNA expression of gcCited3a and gcCited3b is strongly induced by hypoxia in the kidney and liver, respectively. Luciferase reporter assays demonstrated that both gene promoters are activated by gcHIF-1. Further, ChIP assays comparing normal and hypoxic conditions reveal differential in vivo binding of gcHIF-1 to both gene promoters in kidney and liver tissues. HRE-luciferase reporter assays demonstrated that both gcCITED3a and gcCITED3b proteins inhibit gcHIF-1 transcriptional activity, and GST pull-down assays confirmed that both proteins bind specifically to the CH1 domain of the grass carp p300 protein. Conclusion The grass carp gcCITED3a and gcCITED3b genes are differentially expressed and regulated in different fish organs in response to hypoxic stress. This is the first report demonstrating in vivo regulation of two closely-related CITED3 isogenes by HIF-1, as well as CITED3 regulation of HIF-1 transcriptional activity in fish. Overall, our findings suggest that unique molecular mechanisms operate through these two gcCITED3 isoforms that likely play an important regulatory role in the hypoxic response in the grass carp.
Collapse
Affiliation(s)
- Patrick K S Ng
- Department of Biology and Chemistry, City University of Hong Kong, Kowloon Tong, Hong Kong Special Administrative Region, PR China
| | | | | | | | | | | |
Collapse
|
16
|
Edmunds RC, van Herwerden L, Smith-Keune C, Jerry DR. Comparative characterization of a temperature responsive gene (lactate dehydrogenase-B, ldh-b) in two congeneric tropical fish, Lates calcarifer and Lates niloticus. Int J Biol Sci 2009; 5:558-69. [PMID: 19787021 PMCID: PMC2737716 DOI: 10.7150/ijbs.5.558] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Accepted: 08/26/2009] [Indexed: 11/05/2022] Open
Abstract
The characterization of candidate loci is a critical step in obtaining insight into adaptation and acclimation of organisms. In this study of two non-model tropical (to sub-tropical) congeneric perciformes (Lates calcarifer and Lates niloticus) we characterized both coding and non-coding regions of lactate dehydrogenase-B (ldh-b), a locus which exhibits temperature-adaptive differences among temperate and sub-tropical populations of the North American killifish Fundulus heteroclitus. Ldh-b was 5,004 and 3,527 bp in length in L. calcarifer and L. niloticus, respectively, with coding regions comprising 1,005 bp in both species. A high level of sequence homology existed between species for both coding and non-coding regions of ldh-b (> 97% homology), corresponding to a 98.5% amino acid sequence homology. All six known functional sites within the encoded protein sequence (LDH-B) were conserved between the two Lates species. Ten simple sequence repeat (SSR) motifs (mono-, di-, tri- and tetranucleotide) and thirty putative microRNA elements (miRNAs) were identified within introns 1, 2, 5 and 6 of both Lates species. Five single nucleotide polymorphisms (SNPs) were also identified within miRNA containing intron regions. Such SNPs are implicated in several complex human conditions and/or diseases (as demonstrated by extensive genome-wide association studies). This novel characterization serves as a platform to further examine how non-model species may respond to changes in their native temperatures, which are expected to increase by up to 6 degrees C over the next century.
Collapse
Affiliation(s)
- Richard C Edmunds
- Molecular Evolution and Ecology Laboratory, School of Marine & Tropical Biology, James Cook University, Townsville QLD 4811, Australia.
| | | | | | | |
Collapse
|
17
|
Rees BB, Figueroa YG, Wiese TE, Beckman BS, Schulte PM. A novel hypoxia-response element in the lactate dehydrogenase-B gene of the killifish Fundulus heteroclitus. Comp Biochem Physiol A Mol Integr Physiol 2009; 154:70-7. [PMID: 19439190 DOI: 10.1016/j.cbpa.2009.05.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2009] [Revised: 05/04/2009] [Accepted: 05/05/2009] [Indexed: 12/11/2022]
Abstract
Previous studies have suggested that the lactate dehydrogenase-B gene (Ldh-B) of the Atlantic killifish, Fundulus heteroclitus, is a hypoxia-responsive gene. Here, we demonstrate that the F. heteroclitus Ldh-B promoter confers hypoxia-dependence upon reporter gene expression in transiently transfected mammalian (Hep3B) and fish (RTG-2 and RTH-149) cells in culture. Mutation and deletion analyses identified a putative hypoxia-response element (HRE) between 109 and 90 nucleotides upstream of the major start site. This HRE is characterized by the sequence 5'-GATGTG-3' spaced by 8 nucleotides from a perfect inverted repeat, and both sites are necessary for hypoxic induction of reporter gene expression in mammalian and fish cells. This HRE differs from the canonical sequence at one nucleotide position that is invariant among HREs from a wide range of hypoxia-sensitive genes. In fish cells, maximal induction of reporter gene expression driven by this HRE occurred at the lowest oxygen level tested (0.5%), took 48 h to 96 h, and was independent of glucose concentration (between 5.6 and 25 mM). Under all conditions tested, hypoxic induction of gene expression was lower in RTH-149 cells than in RTG-2, suggesting a potential defect in hypoxia signaling in RTH-149 cells. These results demonstrate that the F. heteroclitus Ldh-B promoter contains a novel HRE that is capable of driving reporter gene expression in a sequence-specific and oxygen-, time-, and cell line-dependent manner.
Collapse
Affiliation(s)
- Bernard B Rees
- Department of Biological Sciences, University of New Orleans, New Orleans, LA 70148, USA.
| | | | | | | | | |
Collapse
|
18
|
Functional and adaptive significance of differentially expressed lactate dehydrogenase isoenzymes in tissues of four obligatory air-breathing Channa species. Biologia (Bratisl) 2009. [DOI: 10.2478/s11756-009-0017-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
19
|
Esbaugh AJ, Perry SF, Gilmour KM. Hypoxia-inducible carbonic anhydrase IX expression is insufficient to alleviate intracellular metabolic acidosis in the muscle of zebrafish,Danio rerio. Am J Physiol Regul Integr Comp Physiol 2009; 296:R150-60. [DOI: 10.1152/ajpregu.90685.2008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recent evidence suggests that carbonic anhydrase (CA) IX in humans is under the regulatory control of hypoxia-inducible factor and is overexpressed in certain cancers. However, little is known of its presence in nonmammalian vertebrates or its physiological function in any vertebrate. The objective of this study was to examine and characterize the presence, distribution, induction by hypoxia, and physiological function of CA IX in the zebrafish. Zebrafish CA IX was highly expressed in the eye, brain, and gastrointestinal tract and showed increased expression in the eye, brain, and muscle in response to hypoxia (water Po2= 24 mmHg). The hypothesis that increased CA IX expression during hypoxia would act to attenuate intracellular acidosis was then examined. Muscle intracellular pH (pHi) decreased after 4 h of hypoxic exposure (from 7.15 ± 0.02 to 7.06 ± 0.01 pH units) and did not recover by 24 h. Manipulation of extracellular CA activity via intraperitoneal injection of either bovine CA or the selective extracellular CA inhibitor F3500 revealed that although increased CA activity could fully restore pHi, removal of extracellular activity did not result in further acidosis. An exercise-induced acidosis was also attenuated in fish treated with bovine CA; however, the increased extracellular CA expression resulting from hypoxia had no affect. These data suggest that although extracellular CA can potentially minimize the impact of hypoxia on muscle pHi, the actual level of extracellular CA activity is likely insufficient to achieve this goal, even when enhanced by hypoxia-induced increases in CA IX expression.
Collapse
|
20
|
Yu RMK, Ng PKS, Tan T, Chu DLH, Wu RSS, Kong RYC. Enhancement of hypoxia-induced gene expression in fish liver by the aryl hydrocarbon receptor (AhR) ligand, benzo[a]pyrene (BaP). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2008; 90:235-242. [PMID: 18945501 DOI: 10.1016/j.aquatox.2008.09.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2008] [Revised: 09/04/2008] [Accepted: 09/05/2008] [Indexed: 05/26/2023]
Abstract
Fish in polluted coastal habitats commonly suffer simultaneous exposure to both hypoxia and xenobiotics. Although the adaptive molecular responses to each stress have been described, little is known about the interaction between the signaling pathways mediating these responses. Previous studies in mammalian hepatoma cell lines have shown that hypoxia-inducible factor (HIF)- and/or aryl hydrocarbon receptor (AhR)-activated gene expression is suppressed following co-exposure to hypoxia and the hallmark AhR ligand 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). However, whether similar crosstalk exists in the non-tumor liver tissues of fish and whether other non-TCDD ligands also play the same inhibitory role in this crosstalk remain unknown. Here, the in vivo hepatic mRNA expression profiles of multiple hypoxia- and AhR-responsive genes (later gene expression=mRNA expression of the gene) were examined in the orange-spotted grouper (Epinephelus coioides) upon single and combined exposures to hypoxia and benzo[a]pyrene (BaP). Combined exposure enhanced hypoxia-induced gene expression but did not significantly alter BaP-induced gene expression. Protein carbonyl content was markedly elevated in fish subjected to combined exposure, indicating accumulation of reactive oxygen species (ROS). Application of diethyldithiocarbamate (DDC) to hypoxia-treated grouper liver explants similarly exaggerated hypoxia-induced gene expression as in the combined stress tissues in vivo. These observations suggest that ROS derived from the combined hypoxia and BaP stress have a role in enhancing hypoxia-induced gene expression.
Collapse
Affiliation(s)
- Richard Man Kit Yu
- Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong, China
| | | | | | | | | | | |
Collapse
|
21
|
Evolution and Regulation of the Downstream Gene of Hypoxia-Inducible Factor-1α in Naked Carp (Gymnocypris przewalskii) from Lake Qinghai, China. J Mol Evol 2008; 67:570-80. [DOI: 10.1007/s00239-008-9175-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2008] [Revised: 09/06/2008] [Accepted: 10/06/2008] [Indexed: 01/31/2023]
|
22
|
Kotoh K, Enjoji M, Kato M, Kohjima M, Nakamuta M, Takayanagi R. A new parameter using serum lactate dehydrogenase and alanine aminotransferase level is useful for predicting the prognosis of patients at an early stage of acute liver injury: a retrospective study. COMPARATIVE HEPATOLOGY 2008; 7:6. [PMID: 18700988 PMCID: PMC2527551 DOI: 10.1186/1476-5926-7-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2007] [Accepted: 08/14/2008] [Indexed: 12/12/2022]
Abstract
BACKGROUND Although most patients with severe acute hepatitis are conservatively cured, some progress to acute liver failure (ALF) with a high rate of mortality. Based on the evidence that over-activation of macrophages, followed by disturbance of the hepatic microcirculation, plays a key role in ALF, we hypothesized that the production of serum lactate dehydrogenase (LDH) might increase in the liver under hypoxic conditions and could be an indicator to discriminate between conservative survivors and fatal patients at an early stage. RESULTS To confirm this hypothesis, we developed a new parameter with serum alanine aminotransferase (ALT) and LDH: the ALT-LDH index = serum ALT/(serum LDH - median of normal LDH range). We analyzed retrospectively 33 patients suffering acute liver injury (serum ALT more than 1000 U/L or prothrombin time expressed as international normalized ratio over 1.5 at admission) and evaluated the prognostic value of the ALT-LDH index, comparing data from the first 5 days of hospitalization with the Model for End-Stage Liver Disease (MELD) score. Patients whose symptoms had appeared more than 10 days before admission were excluded from this study. Among those included, 17 were conservative survivors, 9 underwent liver transplantation (LT) and 7 died waiting for LT. We found a rapid increase in the ALT-LDH index in conservative survivors but not in fatal patients. While the prognostic sensitivity and specificity of the ALT-LDH index was low on admission, at day 3 they were superior to the results of MELD. CONCLUSION ALT-LDH index was useful to predict the prognosis of the patients with acute liver injury and should be helpful to begin preparation for LT soon after admission.
Collapse
Affiliation(s)
- Kazuhiro Kotoh
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
| | | | | | | | | | | |
Collapse
|
23
|
Richards JG, Sardella BA, Schulte PM. Regulation of pyruvate dehydrogenase in the common killifish, Fundulus heteroclitus, during hypoxia exposure. Am J Physiol Regul Integr Comp Physiol 2008; 295:R979-90. [PMID: 18579651 DOI: 10.1152/ajpregu.00192.2008] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We examined the metabolic responses of the hypoxia-tolerant killifish (Fundulus heteroclitus) to 15 h of severe hypoxia and recovery with emphasis on muscle substrate usage and the regulation of the mitochondrial protein pyruvate dehydrogenase (PDH), which controls carbohydrate oxidation. Hypoxia survival involved a transient activation of substrate-level phosphorylation in muscle (decreases in [creatine phospate] and increases in [lactate]) during which time mechanisms to reduce overall ATP consumption were initiated. This metabolic transition did not affect total cellular [ATP], but had an impact on cellular energy status as indicated by large decreases in [ATP]/[ADP(free)] and [ATP]/[AMP(free)] and a significant loss of phosphorylation potential and Gibbs free energy of ATP hydrolysis (DeltafG'). The activity of PDH was rapidly (within 3 h) decreased by approximately 50% upon hypoxia exposure and remained depressed relative to normoxic samples throughout. Inactivation of PDH was primarily mediated via posttranslational modification following the accumulation of acetyl-CoA and subsequent activation of pyruvate dehydrogenase kinase (PDK). Estimated changes in cytoplasmic and mitochondrial [NAD(+)]/[NADH] did not parallel one another, suggesting the mitochondrial NADH shuttles do not function during hypoxia exposure. Large increases in the expression of PDK (PDK isoform 2) were consistent with decreased PDH activity; however, these changes in mRNA were not associated with changes in total PDK-2 protein content assessed using mammalian antibodies. No other changes in the expression of other known hypoxia-responsive genes (e.g., lactate dehydrogenase-A or -B) were observed in either muscle or liver.
Collapse
Affiliation(s)
- Jeffrey G Richards
- Dept. of Zoology, The Univ. of British Columbia, 6270 Univ. Blvd., Vancouver, BC, Canada V6T 1Z4.
| | | | | |
Collapse
|
24
|
Burnett KG, Bain LJ, Baldwin WS, Callard GV, Cohen S, Di Giulio RT, Evans DH, Gómez-Chiarri M, Hahn ME, Hoover CA, Karchner SI, Katoh F, MacLatchy DL, Marshall WS, Meyer JN, Nacci DE, Oleksiak MF, Rees BB, Singer TD, Stegeman JJ, Towle DW, Van Veld PA, Vogelbein WK, Whitehead A, Winn RN, Crawford DL. Fundulus as the premier teleost model in environmental biology: opportunities for new insights using genomics. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART D, GENOMICS & PROTEOMICS 2007; 2:257-86. [PMID: 18071578 PMCID: PMC2128618 DOI: 10.1016/j.cbd.2007.09.001] [Citation(s) in RCA: 149] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A strong foundation of basic and applied research documents that the estuarine fish Fundulus heteroclitus and related species are unique laboratory and field models for understanding how individuals and populations interact with their environment. In this paper we summarize an extensive body of work examining the adaptive responses of Fundulus species to environmental conditions, and describe how this research has contributed importantly to our understanding of physiology, gene regulation, toxicology, and ecological and evolutionary genetics of teleosts and other vertebrates. These explorations have reached a critical juncture at which advancement is hindered by the lack of genomic resources for these species. We suggest that a more complete genomics toolbox for F. heteroclitus and related species will permit researchers to exploit the power of this model organism to rapidly advance our understanding of fundamental biological and pathological mechanisms among vertebrates, as well as ecological strategies and evolutionary processes common to all living organisms.
Collapse
Affiliation(s)
- Karen G. Burnett
- Grice Marine Laboratory, College of Charleston, 205 Fort Johnson, Charleston, SC 29412, USA
| | - Lisa J. Bain
- Clemson Institute of Environmental Toxicology, Clemson University; Pendleton, SC 29670, USA
| | - William S. Baldwin
- Clemson Institute of Environmental Toxicology, Clemson University; Pendleton, SC 29670, USA
| | | | - Sarah Cohen
- Romberg Tiburon Center and Department of Biology, San Francisco State University, Tiburon, CA 94120, USA
| | - Richard T. Di Giulio
- Nicholas School of the Environment and Earth Sciences, Duke University, Durham, NC, USA
| | - David H. Evans
- Department of Zoology, University of Florida, Gainesville, FL 32611, USA
| | - Marta Gómez-Chiarri
- Department of Fisheries, Animal and Veterinary Science, University of Rhode Island, Kingston, RI 02881, USA
| | - Mark E. Hahn
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | | | - Sibel I. Karchner
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Fumi Katoh
- Department of Biology, St. Francis Xavier University, Antigonish, N.S. B2G 2W5, Canada
| | - Deborah L. MacLatchy
- Faculty of Science, Wilfred Laurier University, Waterloo, Ontario, Canada N2L 3C5
| | - William S. Marshall
- Department of Biology, St. Francis Xavier University, Antigonish, N.S. B2G 2W5, Canada
| | - Joel N. Meyer
- Nicholas School of the Environment and Earth Sciences, Duke University, Durham, NC, USA
| | - Diane E. Nacci
- US Environmental Protection Agency Office of Research and Development, Narragansett, RI 02882, USA
| | - Marjorie F. Oleksiak
- Rosenstiel School of Marine & Atmospheric Science, University of Miami, Miami, FL 33149, USA
| | - Bernard B. Rees
- Department of Biological Sciences, University of New Orleans, New Orleans, LA 70148, USA
| | - Thomas D. Singer
- School of Optometry, University of Waterloo, Waterloo, ON, N2L 3G1, CANADA
| | - John J. Stegeman
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - David W. Towle
- Center for Marine Functional Genomics, Mount Desert Island Biological Laboratory, Maine 04672, USA
| | - Peter A. Van Veld
- The College of William and Mary, Virginia Institute of Marine Science, Gloucester Point, VA 23062, USA
| | - Wolfgang K. Vogelbein
- The College of William and Mary, Virginia Institute of Marine Science, Gloucester Point, VA 23062, USA
| | - Andrew Whitehead
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Richard N. Winn
- Aquatic Biotechnology and Environmental Laboratory, University of Georgia, Athens, GA 30602, USA
| | - Douglas L. Crawford
- Rosenstiel School of Marine & Atmospheric Science, University of Miami, Miami, FL 33149, USA
| |
Collapse
|
25
|
Wang C, Yuan C, Zhang L, Wu C, Li N. Differential gene expression of phosphoglyceric kinase (PGK) and hypoxic adaptation in chicken. ACTA ACUST UNITED AC 2007; 50:335-42. [PMID: 17609890 DOI: 10.1007/s11427-007-0050-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2006] [Accepted: 01/25/2007] [Indexed: 10/23/2022]
Abstract
Four single-nucleotide polymorphisms (SNP) of the Phosphoglyceric Kinase (PGK) gene were discovered based on comparison of the sequences from an altiplano chicken breed (Tibetan chicken) and two lowland breeds (White Leghorn and Shouguang chicken). Gel-shift results indicate that one of these SNPs, an A-->G mutation at position 59 in exon10, is able to bind hypoxia-induced factor-l (HIF-1), functioning as a hypoxia response element (HRE). The mutant gene results in M-->T mutation at position 379 amino acid. The combined activity of this HRE and HIF-1 could increase correspondingly under a hypoxic stimulus. Hypoxia leads to increased death rates of chicken embryos; while the M-->T mutation described herein is prevalent in healthy embryos grown under hypoxic conditions, thus it may represent an adaptation to hypoxia. Fluorescence quantitative reverse transcription PCR results revealed that HIF-1 upregulates the transcript level of the glycolytic enzyme PGK in the brain and skeletal muscle of animals subjected to hypoxia. Thus, a large amount of ATP is produced by increased glycolysis, allowing the organism to meet energy metabolism demands. As such, we believe this SNP to be an adaptation to the external anoxic environment.
Collapse
Affiliation(s)
- CunFang Wang
- College of Animal Science and Technology, China Agricultural University, Beijing, China
| | | | | | | | | |
Collapse
|
26
|
Ferreira TC, Hertzberg L, Gassmann M, Campos ÉG. The yeast genome may harbor hypoxia response elements (HRE). Comp Biochem Physiol C Toxicol Pharmacol 2007; 146:255-263. [PMID: 17035097 DOI: 10.1016/j.cbpc.2006.08.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2006] [Revised: 08/22/2006] [Accepted: 08/28/2006] [Indexed: 01/28/2023]
Abstract
The hypoxia-inducible factor-1 (HIF-1) is a heterodimeric transcription factor activated when cells are submitted to hypoxia. The heterodimer is composed of two subunits, HIF-1alpha and the constitutively expressed HIF-1beta. During normoxia, HIF-1alpha is degraded by the 26S proteasome, but hypoxia causes HIF-1alpha to be stabilized, enter the nucleus and bind to HIF-1beta, thus forming the active complex. The complex then binds to the regulatory sequences of various genes involved in physiological and pathological processes. The specific regulatory sequence recognized by HIF-1 is the hypoxia response element (HRE) that has the consensus sequence 5'BRCGTGVBBB3'. Although the basic transcriptional regulation machinery is conserved between yeast and mammals, Saccharomyces cerevisiae does not express HIF-1 subunits. However, we hypothesized that baker's yeast has a protein analogous to HIF-1 which participates in the response to changes in oxygen levels by binding to HRE sequences. In this study we screened the yeast genome for HREs using probabilistic motif search tools. We described 24 yeast genes containing motifs with high probability of being HREs (p-value<0.1) and classified them according to biological function. Our results show that S. cerevisiae may harbor HREs and indicate that a transcription factor analogous to HIF-1 may exist in this organism.
Collapse
Affiliation(s)
- Túlio César Ferreira
- Laboratório de Biologia Molecular, Departamento de Biologia Celular, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, DF, 70910-900, Brazil
| | - Libi Hertzberg
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel; Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Max Gassmann
- Institute of Veterinary Physiology, Vetsuisse Faculty and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Winterthurerstrasse 260, CH-8057, Zurich, Switzerland
| | - Élida Geralda Campos
- Laboratório de Biologia Molecular, Departamento de Biologia Celular, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, DF, 70910-900, Brazil.
| |
Collapse
|
27
|
Rissanen E, Tranberg HK, Sollid J, Nilsson GE, Nikinmaa M. Temperature regulates hypoxia-inducible factor-1 (HIF-1) in a poikilothermic vertebrate, crucian carp (Carassius carassius). ACTA ACUST UNITED AC 2006; 209:994-1003. [PMID: 16513925 DOI: 10.1242/jeb.02103] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Hypoxia-inducible transcription factor-1 (HIF-1) is a master regulator of hypoxia-induced gene responses. To find out whether HIF-1 function is involved in gene expression changes associated with temperature acclimation as well as in hypoxia adaptation in poikilotherms, we studied HIF-1 DNA binding activity and HIF-1alpha expression in normoxia and during hypoxia (0.7 mg l(-1) O2) in crucian carp at temperatures of 26, 18 and 8 degrees C. Temperature had a marked influence on HIF-1 in normoxia. Although HIF-1alpha mRNA levels remained unaltered, cold acclimation (8 degrees C) increased HIF-1alpha protein amounts in the liver, gills and heart and HIF-1 DNA binding activity in the heart, gills and kidney of crucian carp by two- to threefold compared to warm acclimated fish (26 degrees C). In the heart and kidney HIF-1 activity was already significantly increased in the 18 degrees C acclimated fish. Temperature also affected hypoxic regulation of HIF-1. Although hypoxia initially increased amounts of HIF-1alpha protein in all studied tissues at every temperature, except for liver at 18 degrees C, HIF-1 activity increased only in the heart of 8 degrees C acclimated and in the gills of 18 degrees C acclimated fish. At 8 degrees C HIF-1alpha mRNA levels increased transiently in the gills after 6 h of hypoxia and in the kidney after 48 h of hypoxia. In the gills at 26 degrees C HIF-1alpha mRNA levels increased after 6 h of hypoxia and remained above normoxic levels for up to 48 h of hypoxia. These results show that HIF-1 is involved in controlling gene responses to both oxygen and temperature in crucian carp. No overall transcriptional control mechanism has been described for low temperature acclimation in poikilotherms, but the present results suggest that HIF-1 could have a role in such regulation. Moreover, this study highlights interaction of the two prime factors defining metabolism, temperature and oxygen, in the transcriptional control of metabolic homeostasis in animals.
Collapse
Affiliation(s)
- Eeva Rissanen
- Centre of Excellence in Evolutionary Genetics and Physiology, Department of Biology, University of Turku, Finland.
| | | | | | | | | |
Collapse
|
28
|
Abstract
The role of oxygen in regulating patterns of gene expression in mammalian development, physiology, and pathology has received increasing attention, especially after the discovery of the hypoxia-inducible factor (HIF), a transcription factor that has been likened to a "master switch" in the transcriptional response of mammalian cells and tissues to low oxygen. At present, considerably less is known about the molecular responses of nonmammalian vertebrates and invertebrates to hypoxic exposure. Because many animals live in aquatic habitats that are variable in oxygen tension, it is relevant to study oxygen-dependent gene expression in these animals. The purpose of this review is to discuss hypoxia-induced gene expression in fishes from an evolutionary and ecological context. Recent studies have described homologs of HIF in fish and have begun to evaluate their function. A number of physiological processes are known to be altered by hypoxic exposure of fish, although the evidence linking them to HIF is less well developed. The diversity of fish presents many opportunities to evaluate if inter- and intraspecific variation in HIF structure and function correlate with hypoxia tolerance. Furthermore, as an aquatic group, fish offer the opportunity to examine the interactions between hypoxia and other stressors, including pollutants, common in aquatic environments. It is possible, if not likely, that results obtained by studying the molecular responses of fish to hypoxia will find parallels in the oxygen-dependent responses of mammals, including humans. Moreover, novel responses to hypoxia could be discovered through studies of this diverse and species-rich group.
Collapse
Affiliation(s)
- Mikko Nikinmaa
- Dept. of Biology, Univ. of Turku, FI-20014 Turku, Finland.
| | | |
Collapse
|
29
|
Ahmad R, Hasnain AU. Ontogenetic changes and developmental adjustments in lactate dehydrogenase isozymes of an obligate air-breathing fish Channa punctatus during deprivation of air access. Comp Biochem Physiol B Biochem Mol Biol 2005; 140:271-8. [PMID: 15649774 DOI: 10.1016/j.cbpc.2004.10.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2004] [Revised: 10/22/2004] [Accepted: 10/26/2004] [Indexed: 11/21/2022]
Abstract
In air-breathing snakehead Channa punctatus, Ldh-B is expressed at all ontogenetic and developmental stages, while Ldh-A is expressed temporally in pre-hatchlings 12-13 days ahead of bimodal respiration marked by air-breathing. Remarkable differences are observed in the LDH isozyme expression among various ontogenetic and developmental stages upon denying air access. When denied air access, water-breathing larvae show two distinct characteristics: (i) they survive longer than transitory air-breathers due to independence from air-breathing and (ii) there is more transient induction of Ldh-B than Ldh-A. Transition to bimodal breathing, which occurred post-hatching in 15-day old larvae, is coincidental with inducibility of Ldh-A and concomitant down-regulation of Ldh-B. Heart tissue from air-breathing adults denied air access shows a preferential expression of LDH-A subunit and slight down-regulation of LDH-B. Heterotetramers of A and B subunits participate in adjusting LDH levels among those stages which either precede air-breathing switchover, or are subsequent to this transition. The contribution of heterotetramers depends on the stage-specific levels of LDH homotetramers A(4) or B(4). Scaling of muscle mass during growth, tolerance to extended deprivation of air access and induction of Ldh-A are correlated. Response to restoring air contact indicated that advanced air-breathing stages of C. punctatus possess an inherent capacity to sense surface air. In kinetic properties, LDH isozymes of C. punctatus are teleost-like but species specificity is displayed in oxidative potential by cardiac muscle and in L-lactate reduction by skeletal muscle.
Collapse
Affiliation(s)
- Riaz Ahmad
- Laboratory of Biochemical Genetics, Department of Zoology, Aligarh Muslim University, Aligarh-202002, India
| | | |
Collapse
|
30
|
|
31
|
Choi JW, Park SC, Kang GH, Liu JO, Youn HD. Nur77 activated by hypoxia-inducible factor-1alpha overproduces proopiomelanocortin in von Hippel-Lindau-mutated renal cell carcinoma. Cancer Res 2004; 64:35-9. [PMID: 14729605 DOI: 10.1158/0008-5472.can-03-0145] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Mutation in the von Hippel-Lindau (VHL) protein associated with renal cell carcinoma causes hypoxia-inducible factor (HIF) to stabilize and consequently to induce various HIF-targeting proteins. In this study, we found that proopiomelanocortin (POMC), an adrenocorticotropic hormone precursor, is up-regulated constitutively in VHL-mutated renal cell carcinoma. A critical transcription factor responsible for POMC overproduction was identified as Nur77, a member of the orphan steroid receptor superfamily. Little is known about how VHL mutation leads to activation of Nur77. We report that Nur77 is directly regulated by HIF. We show that HIF-1alpha, but not HIF-2alpha, binds to a putative HIF responsive element in the Nur77 promoter, activating the expression of Nur77. Mutation or deletion of the HIF binding site in the Nur77 promoter abrogates activation of a luciferase reporter gene under the control of Nur77 promoter by HIF-1alpha. The treatment of Nur77 antisense oligonucleotide reduces POMC transcription under hypoxic conditions. We confirmed that Nur77 and POMC are up-regulated in VHL-mutated renal cell carcinoma. In this study, we provide the first molecular evidence that Nur77 activated by HIF under hypoxic conditions regulates production of the peptide hormone precursor POMC.
Collapse
MESH Headings
- Amino Acid Substitution
- Base Sequence
- Carcinoma, Renal Cell/genetics
- Cobalt/pharmacology
- DNA Primers
- DNA-Binding Proteins/drug effects
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/physiology
- Genes, Tumor Suppressor
- Humans
- Hypoxia-Inducible Factor 1, alpha Subunit
- Kidney Neoplasms/genetics
- Mutation
- Nuclear Receptor Subfamily 4, Group A, Member 1
- Pro-Opiomelanocortin/genetics
- Promoter Regions, Genetic/drug effects
- Receptors, Cytoplasmic and Nuclear
- Receptors, Steroid
- Reverse Transcriptase Polymerase Chain Reaction/methods
- Transcription Factors/drug effects
- Transcription Factors/genetics
- Transcription Factors/pharmacology
- Transcription Factors/physiology
- Transcription, Genetic
- Tumor Cells, Cultured
- Tumor Suppressor Proteins/genetics
- Ubiquitin-Protein Ligases/genetics
- Von Hippel-Lindau Tumor Suppressor Protein
- von Hippel-Lindau Disease/genetics
Collapse
Affiliation(s)
- Ji-Woong Choi
- Department of Biochemistry and Molecular Biology, Cancer Research Institute, Seoul, South Korea
| | | | | | | | | |
Collapse
|
32
|
Buckley BA, Hofmann GE. Thermal acclimation changes DNA-binding activity of heat shock factor 1(HSF1) in the gobyGillichthys mirabilis: implications for plasticity in the heat-shock response in natural populations. J Exp Biol 2002; 205:3231-40. [PMID: 12235201 DOI: 10.1242/jeb.205.20.3231] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYThe intracellular build-up of thermally damaged proteins following exposure to heat stress results in the synthesis of a family of evolutionarily conserved proteins called heat shock proteins (Hsps) that act as molecular chaperones, protecting the cell against the aggregation of denatured proteins. The transcriptional regulation of heat shock genes by heat shock factor 1(HSF1) has been extensively studied in model systems, but little research has focused on the role HSF1 plays in Hsp gene expression in eurythermal organisms from broadly fluctuating thermal environments. The threshold temperature for Hsp induction in these organisms shifts with the recent thermal history of the individual but the mechanism by which this plasticity in Hsp induction temperature is achieved is unknown. We examined the effect of thermal acclimation on the heat-activation of HSF1 in the eurythermal teleost Gillichthys mirabilis. After a 5-week acclimation period (at 13, 21 or 28°C) the temperature of HSF1 activation was positively correlated with acclimation temperature. HSF1 activation peaked at 27°C in fish acclimated to 13°C, at 33°C in the 21°C group, and at 36°C in the 28°C group. Concentrations of both HSF1 and Hsp70 in the 28°C group were significantly higher than in the colder acclimated fish. Plasticity in HSF1 activation may be important to the adjustable nature of the heat shock response in eurythermal organisms and the environmental control of Hsp gene expression.
Collapse
Affiliation(s)
- Bradley A Buckley
- Department of Biology, Arizona State University, Tempe 85287-1501, USA
| | | |
Collapse
|
33
|
Nikinmaa M. Oxygen-dependent cellular functions--why fishes and their aquatic environment are a prime choice of study. Comp Biochem Physiol A Mol Integr Physiol 2002; 133:1-16. [PMID: 12160868 DOI: 10.1016/s1095-6433(02)00132-0] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Owing to the variability of oxygen tension in aquatic, especially the freshwater environment, oxygen has been a major force in the evolution of fishes. Their long evolutionary history, and the present different oxygen requirements between species, and acclimatory responses to hypoxic and hyperoxic conditions make fishes prime models in the study of oxygen-dependent cellular functions and their regulation. In the present article oxygen-dependent membrane transport, cellular signalling, energy metabolism, gene expression and apoptosis are reviewed with an emphasis on available results on fish. Available data on oxygen sensing are described and examples on the cascade from sensing oxygen to its physiological effects are given. From the data it is clear that hitherto fish have not been utilised in the study of oxygen-dependent cellular regulation as much as their evolutionary history and present oxygen requirements would give possibilities to. Even more generally, oxygen has hitherto seldom been a carefully controlled key variable in experimental cell biology.
Collapse
Affiliation(s)
- Mikko Nikinmaa
- Department of Biology, University of Turku, FIN-20014, Turku, Finland.
| |
Collapse
|
34
|
Powell WH, Hahn ME. Identification and functional characterization of hypoxia-inducible factor 2alpha from the estuarine teleost, Fundulus heteroclitus: interaction of HIF-2alpha with two ARNT2 splice variants. THE JOURNAL OF EXPERIMENTAL ZOOLOGY 2002; 294:17-29. [PMID: 11932946 DOI: 10.1002/jez.10074] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The hypoxia-inducible factors (HIFs) are dimeric transcription factors that mediate changes in gene expression during adaptation of animals to oxygen stress. Both alpha (HIFalpha) and beta (ARNT) subunits are members of the basic helix-loop-helix/Per-ARNT-Sim family of proteins. Mammals have at least three different HIF-alpha subunits, paralogous proteins expressed in tissue-specific fashion (HIF-1alpha, HIF-2alpha, and HIF-3alpha). However, the diversity and functional properties of teleost HIFs are poorly understood. In efforts to characterize mechanisms of hypoxia adaptation in estuarine fish, we have isolated cDNAs encoding HIF subunits from Fundulus heteroclitus (Atlantic killifish or mummichog), including a HIF-2alpha homolog and ARNT2alt, a splice variant of ARNT2 that contains an additional exon encoding 16 amino acids near the amino terminus. HIF-2alpha protein synthesized in vitro binds cognate DNA elements in concert with either Fundulus ARNT2 splice variant or murine ARNT1. HIF-2alpha, ARNT2, and ARNT2alt mRNAs are expressed in all organs examined. The HIF-2alpha cDNA encodes a protein of 96.4 kDa, sharing 53-54% identity with mammalian and avian orthologs. The oxygen-dependent degradation domain, however, exhibits substantial divergence from well-conserved mammalian sequences, suggesting the possibility of important functional differences, perhaps in the sensitivity to induction of activity by hypoxia. Hypoxia-tolerant fishes such as F. heteroclitus represent a unique opportunity for the study of functional and evolutionary aspects of adaptation to hypoxia at the molecular, cellular, and organismal levels. This study extends the understanding of hypoxia signaling in fish, the evolution and diversity of HIF function, and the evolution of the PAS family of proteins.
Collapse
Affiliation(s)
- Wade H Powell
- Biology Department, Kenyon College, Gambier, Ohio 43022, USA.
| | | |
Collapse
|