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Brewitz L, Tumber A, Zhang X, Schofield CJ. Small-molecule active pharmaceutical ingredients of approved cancer therapeutics inhibit human aspartate/asparagine-β-hydroxylase. Bioorg Med Chem 2020; 28:115675. [PMID: 33069066 PMCID: PMC7588595 DOI: 10.1016/j.bmc.2020.115675] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 07/15/2020] [Accepted: 07/16/2020] [Indexed: 12/20/2022]
Abstract
Human aspartate/asparagine-β-hydroxylase (AspH) is a 2-oxoglutarate (2OG) dependent oxygenase that catalyses the hydroxylation of Asp/Asn-residues of epidermal growth factor-like domains (EGFDs). AspH is reported to be upregulated on the cell surface of invasive cancer cells in a manner distinguishing healthy from cancer cells. We report studies on the effect of small-molecule active pharmaceutical ingredients (APIs) of human cancer therapeutics on the catalytic activity of AspH using a high-throughput mass spectrometry (MS)-based inhibition assay. Human B-cell lymphoma-2 (Bcl-2)-protein inhibitors, including the (R)-enantiomer of the natural product gossypol, were observed to efficiently inhibit AspH, as does the antitumor antibiotic bleomycin A2. The results may help in the design of AspH inhibitors with the potential of increased selectivity compared to the previously identified Fe(II)-chelating or 2OG-competitive inhibitors. With regard to the clinical use of bleomycin A2 and of the Bcl-2 inhibitor venetoclax, the results suggest that possible side-effects mediated through the inhibition of AspH and other 2OG oxygenases should be considered.
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Affiliation(s)
- Lennart Brewitz
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
| | - Anthony Tumber
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
| | - Xiaojin Zhang
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom; Laboratory of Drug Design and Discovery, Department of Chemistry, China Pharmaceutical University, Nanjing 211198, China
| | - Christopher J Schofield
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom.
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Wertman JN, Melong N, Stoyek MR, Piccolo O, Langley S, Orr B, Steele SL, Razaghi B, Berman JN. The identification of dual protective agents against cisplatin-induced oto- and nephrotoxicity using the zebrafish model. eLife 2020; 9:e56235. [PMID: 32720645 PMCID: PMC7470826 DOI: 10.7554/elife.56235] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 07/20/2020] [Indexed: 12/17/2022] Open
Abstract
Dose-limiting toxicities for cisplatin administration, including ototoxicity and nephrotoxicity, impact the clinical utility of this effective chemotherapy agent and lead to lifelong complications, particularly in pediatric cancer survivors. Using a two-pronged drug screen employing the zebrafish lateral line as an in vivo readout for ototoxicity and kidney cell-based nephrotoxicity assay, we screened 1280 compounds and identified 22 that were both oto- and nephroprotective. Of these, dopamine and L-mimosine, a plant-based amino acid active in the dopamine pathway, were further investigated. Dopamine and L-mimosine protected the hair cells in the zebrafish otic vesicle from cisplatin-induced damage and preserved zebrafish larval glomerular filtration. Importantly, these compounds did not abrogate the cytotoxic effects of cisplatin on human cancer cells. This study provides insights into the mechanisms underlying cisplatin-induced oto- and nephrotoxicity and compelling preclinical evidence for the potential utility of dopamine and L-mimosine in the safer administration of cisplatin.
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Affiliation(s)
- Jaime N Wertman
- Dalhousie University, Department of Microbiology and ImmunologyHalifaxCanada
- IWK Health Centre, Department of PediatricsHalifaxCanada
| | - Nicole Melong
- IWK Health Centre, Department of PediatricsHalifaxCanada
- CHEO Research InstituteOttawaCanada
| | - Matthew R Stoyek
- Dalhousie University, Department of Physiology & BiophysicsHalifaxCanada
| | - Olivia Piccolo
- IWK Health Centre, Department of PediatricsHalifaxCanada
- McMaster University, Department of Global HealthHamiltonCanada
| | | | - Benno Orr
- University of Toronto, Department of Molecular GeneticsTorontoCanada
| | | | - Babak Razaghi
- Dalhousie University, Faculty of DentistryHalifaxCanada
| | - Jason N Berman
- IWK Health Centre, Department of PediatricsHalifaxCanada
- CHEO Research InstituteOttawaCanada
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Brewitz L, Tumber A, Pfeffer I, McDonough MA, Schofield CJ. Aspartate/asparagine-β-hydroxylase: a high-throughput mass spectrometric assay for discovery of small molecule inhibitors. Sci Rep 2020; 10:8650. [PMID: 32457455 PMCID: PMC7251097 DOI: 10.1038/s41598-020-65123-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 04/28/2020] [Indexed: 12/20/2022] Open
Abstract
The human 2-oxoglutarate dependent oxygenase aspartate/asparagine-β-hydroxylase (AspH) catalyses the hydroxylation of Asp/Asn-residues in epidermal growth factor-like domains (EGFDs). AspH is upregulated on the surface of malign cancer cells; increased AspH levels correlate with tumour invasiveness. Due to a lack of efficient assays to monitor the activity of isolated AspH, there are few reports of studies aimed at identifying small-molecule AspH inhibitors. Recently, it was reported that AspH substrates have a non-canonical EGFD disulfide pattern. Here we report that a stable synthetic thioether mimic of AspH substrates can be employed in solid phase extraction mass spectrometry based high-throughput AspH inhibition assays which are of excellent robustness, as indicated by high Z'-factors and good signal-to-noise/background ratios. The AspH inhibition assay was applied to screen approximately 1500 bioactive small-molecules, including natural products and active pharmaceutical ingredients of approved human therapeutics. Potent AspH inhibitors were identified from both compound classes. Our AspH inhibition assay should enable the development of potent and selective small-molecule AspH inhibitors and contribute towards the development of safer inhibitors for other 2OG oxygenases, e.g. screens of the hypoxia-inducible factor prolyl-hydroxylase inhibitors revealed that vadadustat inhibits AspH with moderate potency.
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Affiliation(s)
- Lennart Brewitz
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA, Oxford, United Kingdom
| | - Anthony Tumber
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA, Oxford, United Kingdom
| | - Inga Pfeffer
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA, Oxford, United Kingdom
| | - Michael A McDonough
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA, Oxford, United Kingdom
| | - Christopher J Schofield
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA, Oxford, United Kingdom.
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Saxena D, Spino M, Tricta F, Connelly J, Cracchiolo BM, Hanauske AR, D’Alliessi Gandolfi D, Mathews MB, Karn J, Holland B, Park MH, Pe’ery T, Palumbo PE, Hanauske-Abel HM. Drug-Based Lead Discovery: The Novel Ablative Antiretroviral Profile of Deferiprone in HIV-1-Infected Cells and in HIV-Infected Treatment-Naive Subjects of a Double-Blind, Placebo-Controlled, Randomized Exploratory Trial. PLoS One 2016; 11:e0154842. [PMID: 27191165 PMCID: PMC4871512 DOI: 10.1371/journal.pone.0154842] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 04/18/2016] [Indexed: 01/19/2023] Open
Abstract
UNLABELLED Antiretrovirals suppress HIV-1 production yet spare the sites of HIV-1 production, the HIV-1 DNA-harboring cells that evade immune detection and enable viral resistance on-drug and viral rebound off-drug. Therapeutic ablation of pathogenic cells markedly improves the outcome of many diseases. We extend this strategy to HIV-1 infection. Using drug-based lead discovery, we report the concentration threshold-dependent antiretroviral action of the medicinal chelator deferiprone and validate preclinical findings by a proof-of-concept double-blind trial. In isolate-infected primary cultures, supra-threshold concentrations during deferiprone monotherapy caused decline of HIV-1 RNA and HIV-1 DNA; did not allow viral breakthrough for up to 35 days on-drug, indicating resiliency against viral resistance; and prevented, for at least 87 days off-drug, viral rebound. Displaying a steep dose-effect curve, deferiprone produced infection-independent deficiency of hydroxylated hypusyl-eIF5A. However, unhydroxylated deoxyhypusyl-eIF5A accumulated particularly in HIV-infected cells; they preferentially underwent apoptotic DNA fragmentation. Since the threshold, ascertained at about 150 μM, is achievable in deferiprone-treated patients, we proceeded from cell culture directly to an exploratory trial. HIV-1 RNA was measured after 7 days on-drug and after 28 and 56 days off-drug. Subjects who attained supra-threshold concentrations in serum and completed the protocol of 17 oral doses, experienced a zidovudine-like decline of HIV-1 RNA on-drug that was maintained off-drug without statistically significant rebound for 8 weeks, over 670 times the drug's half-life and thus clearance from circulation. The uniform deferiprone threshold is in agreement with mapping of, and crystallographic 3D-data on, the active site of deoxyhypusyl hydroxylase (DOHH), the eIF5A-hydroxylating enzyme. We propose that deficiency of hypusine-containing eIF5A impedes the translation of mRNAs encoding proline cluster ('polyproline')-containing proteins, exemplified by Gag/p24, and facilitated by the excess of deoxyhypusine-containing eIF5A, releases the innate apoptotic defense of HIV-infected cells from viral blockade, thus depleting the cellular reservoir of HIV-1 DNA that drives breakthrough and rebound. TRIAL REGISTRATION ClinicalTrial.gov NCT02191657.
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Affiliation(s)
- Deepti Saxena
- Department of Pediatrics, New Jersey Medical School, Rutgers University, Newark, New Jersey, United States of America
| | - Michael Spino
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
- ApoPharma Inc., Toronto, Ontario, Canada
| | | | | | - Bernadette M. Cracchiolo
- Department of Obstetrics, Gynecology and Women’s Health, New Jersey Medical School, Rutgers University, Newark, New Jersey, United States of America
| | - Axel-Rainer Hanauske
- Oncology Center and Medical Clinic III, Asklepios Klinik St. Georg, Hamburg, Germany
| | | | - Michael B. Mathews
- Department of Medicine, New Jersey Medical School, Rutgers University, Newark, New Jersey, United States of America
| | - Jonathan Karn
- Department of Molecular Biology and Microbiology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Bart Holland
- Department of Medicine, New Jersey Medical School, Rutgers University, Newark, New Jersey, United States of America
| | - Myung Hee Park
- Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institute of Health, Bethesda, Maryland, United States of America
| | - Tsafi Pe’ery
- Department of Medicine, New Jersey Medical School, Rutgers University, Newark, New Jersey, United States of America
| | - Paul E. Palumbo
- Department of Pediatrics, New Jersey Medical School, Rutgers University, Newark, New Jersey, United States of America
- * E-mail: (PEP); (HMHA)
| | - Hartmut M. Hanauske-Abel
- Department of Pediatrics, New Jersey Medical School, Rutgers University, Newark, New Jersey, United States of America
- Department of Obstetrics, Gynecology and Women’s Health, New Jersey Medical School, Rutgers University, Newark, New Jersey, United States of America
- Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers University, Newark, New Jersey, United States of America
- * E-mail: (PEP); (HMHA)
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Nishimura K, Tokida M, Katsuyama H, Nakagawa H, Matsuo S. The effect of hemin-induced oxidative stress on erythropoietin production in HepG2 cells. Cell Biol Int 2014; 38:1321-9. [PMID: 24962609 DOI: 10.1002/cbin.10329] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 05/17/2014] [Indexed: 12/12/2022]
Abstract
Erythropoietin (EPO) and iron are both indispensable hematopoietic factors and are often studied in humans and rodents. Iron activates prolyl hydroxylases (PHDs) and promotes the degradation of the α-subunit of hypoxia inducible factor (HIF), which regulates EPO production. Iron also causes oxidative stress. Oxidative stress leads to alterations in the levels of multiple factors that regulate HIF and EPO production. It is thought that iron influences EPO production by altering two pathways, namely PHDs activity and oxidative stress. We studied the differential effect of varying concentrations of hemin, an iron-containing porphyrin, on EPO production in HepG2 cells. Hemin at 100 µM reduced EPO mRNA expression. The hemin-induced reduction of EPO mRNA levels was attenuated at concentrations greater than 200 µM and EPO production increased in the presence of 500 µM hemin. In comparison, protoporphyrin IX, iron-free hemin did not influence EPO mRNA expression. Additionally, malondialdehyde (MDA) concentrations and superoxide dismutase (SOD) activity significantly increased with 300 µM hemin. Importantly, the antioxidant tempol inhibited the hemin-induced (500 µM) increase in EPO mRNA levels. In conclusion, these results suggest that restraint of EPO production by hemin was offset by the promotion of EPO production by hemin-induced oxidative stress at hemin concentrations greater than 300 µM.
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Affiliation(s)
- Kazuhiko Nishimura
- Laboratory of Bioenvironmental Sciences, Course of Veterinary Science, Graduate School of Life Environmental Sciences, Osaka Prefecture University, 1-58 Rinku Ohrai-Kita, Izumisano, Osaka, 598-8531, Japan
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Chen YH, Lu PJ, Hulme C, Shaw AY. Synthesis of (E)-5-Methoxy-2-styryl-4-pyrones as Potent Growth-Inhibitory Agents Against Hepatocellular Carcinoma Cells. J Heterocycl Chem 2014. [DOI: 10.1002/jhet.1663] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Yu-Hua Chen
- Department of Chemistry; Tamkang University; New Taipei City 251 Taiwan
| | - Pei-Jung Lu
- Institute of Clinical Medicine; National Cheng Kung University; Tainan 701 Taiwan
| | - Christopher Hulme
- Department of Pharmacology and Toxicology, College of Pharmacy; The University of Arizona; Tucson AZ 85737 USA
- BIO5 Oro Valley; The University of Arizona; Oro Valley AZ 85737 USA
| | - Arthur Y. Shaw
- Department of Pharmacology and Toxicology, College of Pharmacy; The University of Arizona; Tucson AZ 85737 USA
- BIO5 Oro Valley; The University of Arizona; Oro Valley AZ 85737 USA
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Hanauske-Abel HM, Saxena D, Palumbo PE, Hanauske AR, Luchessi AD, Cambiaghi TD, Hoque M, Spino M, Gandolfi DD, Heller DS, Singh S, Park MH, Cracchiolo BM, Tricta F, Connelly J, Popowicz AM, Cone RA, Holland B, Pe’ery T, Mathews MB. Drug-induced reactivation of apoptosis abrogates HIV-1 infection. PLoS One 2013; 8:e74414. [PMID: 24086341 PMCID: PMC3781084 DOI: 10.1371/journal.pone.0074414] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 08/01/2013] [Indexed: 12/11/2022] Open
Abstract
HIV-1 blocks apoptosis, programmed cell death, an innate defense of cells against viral invasion. However, apoptosis can be selectively reactivated in HIV-infected cells by chemical agents that interfere with HIV-1 gene expression. We studied two globally used medicines, the topical antifungal ciclopirox and the iron chelator deferiprone, for their effect on apoptosis in HIV-infected H9 cells and in peripheral blood mononuclear cells infected with clinical HIV-1 isolates. Both medicines activated apoptosis preferentially in HIV-infected cells, suggesting that the drugs mediate escape from the viral suppression of defensive apoptosis. In infected H9 cells, ciclopirox and deferiprone enhanced mitochondrial membrane depolarization, initiating the intrinsic pathway of apoptosis to execution, as evidenced by caspase-3 activation, poly(ADP-ribose) polymerase proteolysis, DNA degradation, and apoptotic cell morphology. In isolate-infected peripheral blood mononuclear cells, ciclopirox collapsed HIV-1 production to the limit of viral protein and RNA detection. Despite prolonged monotherapy, ciclopirox did not elicit breakthrough. No viral re-emergence was observed even 12 weeks after drug cessation, suggesting elimination of the proviral reservoir. Tests in mice predictive for cytotoxicity to human epithelia did not detect tissue damage or activation of apoptosis at a ciclopirox concentration that exceeded by orders of magnitude the concentration causing death of infected cells. We infer that ciclopirox and deferiprone act via therapeutic reclamation of apoptotic proficiency (TRAP) in HIV-infected cells and trigger their preferential elimination. Perturbations in viral protein expression suggest that the antiretroviral activity of both drugs stems from their ability to inhibit hydroxylation of cellular proteins essential for apoptosis and for viral infection, exemplified by eIF5A. Our findings identify ciclopirox and deferiprone as prototypes of selectively cytocidal antivirals that eliminate viral infection by destroying infected cells. A drug-based drug discovery program, based on these compounds, is warranted to determine the potential of such agents in clinical trials of HIV-infected patients.
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Affiliation(s)
- Hartmut M. Hanauske-Abel
- Department of Biochemistry & Molecular Biology, New Jersey Medical School, Rutgers University, Newark, New Jersey, United States of America
- Department of Pediatrics, New Jersey Medical School, Rutgers University, Newark, New Jersey, United States of America
- Department of Obstetrics, Gynecology & Women’s Health, New Jersey Medical School, Rutgers University, Newark, New Jersey, United States of America
| | - Deepti Saxena
- Department of Pediatrics, New Jersey Medical School, Rutgers University, Newark, New Jersey, United States of America
| | - Paul E. Palumbo
- Department of Pediatrics, New Jersey Medical School, Rutgers University, Newark, New Jersey, United States of America
| | - Axel-Rainer Hanauske
- Oncology Center and Medical Clinic III, Asklepios Clinic St. George, Hamburg, Germany
| | - Augusto D. Luchessi
- Department of Biochemistry & Molecular Biology, New Jersey Medical School, Rutgers University, Newark, New Jersey, United States of America
| | - Tavane D. Cambiaghi
- Department of Biochemistry & Molecular Biology, New Jersey Medical School, Rutgers University, Newark, New Jersey, United States of America
| | - Mainul Hoque
- Department of Biochemistry & Molecular Biology, New Jersey Medical School, Rutgers University, Newark, New Jersey, United States of America
| | - Michael Spino
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
- ApoPharma Inc., Toronto, Ontario, Canada
| | | | - Debra S. Heller
- Department of Pathology & Laboratory Medicine, New Jersey Medical School, Rutgers University, Newark, New Jersey, United States of America
| | - Sukhwinder Singh
- Department of Pathology & Laboratory Medicine, New Jersey Medical School, Rutgers University, Newark, New Jersey, United States of America
| | - Myung Hee Park
- Oral and Pharyngeal Cancer Branch, National Institute for Dental and Craniofacial Research, Bethesda, Maryland, United States of America
| | - Bernadette M. Cracchiolo
- Department of Obstetrics, Gynecology & Women’s Health, New Jersey Medical School, Rutgers University, Newark, New Jersey, United States of America
| | | | | | - Anthony M. Popowicz
- Department of Information Technology, Rockefeller University, New York, New York, United States of America
| | - Richard A. Cone
- Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Bart Holland
- Department of Preventive Medicine & Community Health, New Jersey Medical School, Rutgers University, Newark, New Jersey, United States of America
| | - Tsafi Pe’ery
- Department of Biochemistry & Molecular Biology, New Jersey Medical School, Rutgers University, Newark, New Jersey, United States of America
- Department of Medicine, New Jersey Medical School, Rutgers University, Newark, New Jersey, United States of America
| | - Michael B. Mathews
- Department of Biochemistry & Molecular Biology, New Jersey Medical School, Rutgers University, Newark, New Jersey, United States of America
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Kant R, Bali A, Singh N, Jaggi AS. Prolyl 4 hydroxylase: a critical target in the pathophysiology of diseases. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2013; 17:111-20. [PMID: 23626472 PMCID: PMC3634087 DOI: 10.4196/kjpp.2013.17.2.111] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 03/01/2013] [Accepted: 03/06/2013] [Indexed: 01/19/2023]
Abstract
Prolyl 4 hydroxylases (P4H) are iron- and 2-oxoglutamate-dependent dioxygenase enzymes and hypoxia-inducible transcription factor (HIF)-P4Hs play a critical role in the regulating oxygen homeostasis in the local tissues as well in the systemic circulation. Over a period of time, a number of prolyl hydroxylase inhibitors and activators have been developed. By employing the pharmacological tools and transgenic knock out animals, the critical role of these enzymes has been established in the pathophysiology of number of diseases including myocardial infarction, congestive heart failure, stroke, neurodegeneration, inflammatory disease, respiratory diseases, retinopathy and others. The present review discusses the different aspects of these enzymes including their pathophysiological role in disease development.
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Affiliation(s)
- Ravi Kant
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala-147002, India
| | - Anjana Bali
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala-147002, India
| | - Nirmal Singh
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala-147002, India
| | - Amteshwar Singh Jaggi
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala-147002, India
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Müller HD, Cvikl B, Gruber R, Watzek G, Agis H. Prolyl hydroxylase inhibitors increase the production of vascular endothelial growth factor in dental pulp-derived cells. J Endod 2012; 38:1498-503. [PMID: 23063224 DOI: 10.1016/j.joen.2012.08.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 07/29/2012] [Accepted: 08/02/2012] [Indexed: 12/11/2022]
Abstract
INTRODUCTION Prolyl hydroxylase (PHD) inhibitors can induce a proangiogenic response that stimulates regeneration in soft and hard tissues. However, the effect of PHD inhibitors on the dental pulp is unclear. The purpose of this study was to evaluate the effects of PHD inhibitors on the proangiogenic capacity of human dental pulp-derived cells. METHODS To test the response of dental pulp-derived cells to PHD inhibitors, the cells were exposed to dimethyloxalylglycine, desferrioxamine, L-mimosine, and cobalt chloride. To assess the response of dental pulp cells to a capping material supplemented with PHD inhibitors, the cells were treated with supernatants from calcium hydroxide. Viability, proliferation, and protein synthesis were assessed by formazan formation, (3)[H]thymidine, and (3)[H]leucine incorporation assays. The effect on the proangiogenic capacity was measured by immunoassays for vascular endothelial growth factor (VEGF). RESULTS We found that all 4 PHD inhibitors can reduce viability, proliferation, and protein synthesis at high concentrations. At nontoxic concentrations and in the presence of supernatants from calcium hydroxide, PHD inhibitors stimulated the production of VEGF in dental pulp-derived cells. When calcium hydroxide was supplemented with the PHD inhibitors, the supernatants from these preparations did not significantly elevate VEGF levels. CONCLUSIONS These results show that PHD inhibitors can stimulate VEGF production of dental pulp-derived cells, suggesting a corresponding increase in their proangiogenic capacity. Further studies will be required to understand the impact that this might have on pulp regeneration.
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Heli H, Mirtorabi S, Karimian K. Advances in iron chelation: an update. Expert Opin Ther Pat 2011; 21:819-56. [PMID: 21449664 DOI: 10.1517/13543776.2011.569493] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
INTRODUCTION Oxidative stress (caused by excess iron) can result in tissue damage, organ failure and finally death, unless treated by iron chelators. The causative factor in the etiology of a variety of disease states is the presence of iron-generated reactive oxygen species (ROS), which can result in cell damage or which can affect the signaling pathways involved in cell necrosis-apoptosis or organ fibrosis, cancer, neurodegeneration and cardiovascular, hepatic or renal dysfunctions. Iron chelators can reduce oxidative stress by the removal of iron from target tissues. Equally as important, removal of iron from the active site of enzymes that play key roles in various diseases can be of considerable benefit to the patients. AREAS COVERED This review focuses on iron chelators used as therapeutic agents. The importance of iron in oxidative damage is discussed, along with the three clinically approved iron chelators. EXPERT OPINION A number of iron chelators are used as approved therapeutic agents in the treatment of thalassemia major, asthma, fungal infections and cancer. However, as our knowledge about the biochemistry of iron and its role in etiologies of seemingly unrelated diseases increases, new applications of the approved iron chelators, as well as the development of new iron chelators, present challenging opportunities in the areas of drug discovery and development.
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Affiliation(s)
- Hossein Heli
- Islamic Azad University, Science and Research Branch, Department of Chemistry, Fars, 7348113111, Iran
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Evans CE, Humphries J, Mattock K, Waltham M, Wadoodi A, Saha P, Modarai B, Maxwell PJ, Smith A. Hypoxia and Upregulation of Hypoxia-Inducible Factor 1α Stimulate Venous Thrombus Recanalization. Arterioscler Thromb Vasc Biol 2010; 30:2443-51. [DOI: 10.1161/atvbaha.110.215038] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Colin Edward Evans
- From Kings College London (C.E.E., J.H., K.M., M.W., A.W., P.S., B.M., and A.S.), BHF Centre of Research Excellence & NIHR Biomedical Research Centre at Kings Health Partners, Academic Department of Surgery, London, United Kingdom; and Centre for Cell Signalling and Molecular Genetics (P.H.M.), Rayne Institute, University College London, United Kingdom
| | - Julia Humphries
- From Kings College London (C.E.E., J.H., K.M., M.W., A.W., P.S., B.M., and A.S.), BHF Centre of Research Excellence & NIHR Biomedical Research Centre at Kings Health Partners, Academic Department of Surgery, London, United Kingdom; and Centre for Cell Signalling and Molecular Genetics (P.H.M.), Rayne Institute, University College London, United Kingdom
| | - Katherine Mattock
- From Kings College London (C.E.E., J.H., K.M., M.W., A.W., P.S., B.M., and A.S.), BHF Centre of Research Excellence & NIHR Biomedical Research Centre at Kings Health Partners, Academic Department of Surgery, London, United Kingdom; and Centre for Cell Signalling and Molecular Genetics (P.H.M.), Rayne Institute, University College London, United Kingdom
| | - Matthew Waltham
- From Kings College London (C.E.E., J.H., K.M., M.W., A.W., P.S., B.M., and A.S.), BHF Centre of Research Excellence & NIHR Biomedical Research Centre at Kings Health Partners, Academic Department of Surgery, London, United Kingdom; and Centre for Cell Signalling and Molecular Genetics (P.H.M.), Rayne Institute, University College London, United Kingdom
| | - Ashar Wadoodi
- From Kings College London (C.E.E., J.H., K.M., M.W., A.W., P.S., B.M., and A.S.), BHF Centre of Research Excellence & NIHR Biomedical Research Centre at Kings Health Partners, Academic Department of Surgery, London, United Kingdom; and Centre for Cell Signalling and Molecular Genetics (P.H.M.), Rayne Institute, University College London, United Kingdom
| | - Prakash Saha
- From Kings College London (C.E.E., J.H., K.M., M.W., A.W., P.S., B.M., and A.S.), BHF Centre of Research Excellence & NIHR Biomedical Research Centre at Kings Health Partners, Academic Department of Surgery, London, United Kingdom; and Centre for Cell Signalling and Molecular Genetics (P.H.M.), Rayne Institute, University College London, United Kingdom
| | - Bijan Modarai
- From Kings College London (C.E.E., J.H., K.M., M.W., A.W., P.S., B.M., and A.S.), BHF Centre of Research Excellence & NIHR Biomedical Research Centre at Kings Health Partners, Academic Department of Surgery, London, United Kingdom; and Centre for Cell Signalling and Molecular Genetics (P.H.M.), Rayne Institute, University College London, United Kingdom
| | - Patrick J. Maxwell
- From Kings College London (C.E.E., J.H., K.M., M.W., A.W., P.S., B.M., and A.S.), BHF Centre of Research Excellence & NIHR Biomedical Research Centre at Kings Health Partners, Academic Department of Surgery, London, United Kingdom; and Centre for Cell Signalling and Molecular Genetics (P.H.M.), Rayne Institute, University College London, United Kingdom
| | - Alberto Smith
- From Kings College London (C.E.E., J.H., K.M., M.W., A.W., P.S., B.M., and A.S.), BHF Centre of Research Excellence & NIHR Biomedical Research Centre at Kings Health Partners, Academic Department of Surgery, London, United Kingdom; and Centre for Cell Signalling and Molecular Genetics (P.H.M.), Rayne Institute, University College London, United Kingdom
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12
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Heinis M, Simon MT, Ilc K, Mazure NM, Pouysségur J, Scharfmann R, Duvillié B. Oxygen tension regulates pancreatic beta-cell differentiation through hypoxia-inducible factor 1alpha. Diabetes 2010; 59:662-9. [PMID: 20009089 PMCID: PMC2828660 DOI: 10.2337/db09-0891] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Recent evidence indicates that low oxygen tension (pO2) or hypoxia controls the differentiation of several cell types during development. Variations of pO2 are mediated through the hypoxia-inducible factor (HIF), a crucial mediator of the adaptative response of cells to hypoxia. The aim of this study was to investigate the role of pO2 in beta-cell differentiation. RESEARCH DESIGN AND METHODS We analyzed the capacity of beta-cell differentiation in the rat embryonic pancreas using two in vitro assays. Pancreata were cultured either in collagen or on a filter at the air/liquid interface with various pO2. An inhibitor of the prolyl hydroxylases, dimethyloxaloylglycine (DMOG), was used to stabilize HIF1alpha protein in normoxia. RESULTS When cultured in collagen, embryonic pancreatic cells were hypoxic and expressed HIF1alpha and rare beta-cells differentiated. In pancreata cultured on filter (normoxia), HIF1alpha expression decreased and numerous beta-cells developed. During pancreas development, HIF1alpha levels were elevated at early stages and decreased with time. To determine the effect of pO2 on beta-cell differentiation, pancreata were cultured in collagen at increasing concentrations of O2. Such conditions repressed HIF1alpha expression, fostered development of Ngn3-positive endocrine progenitors, and induced beta-cell differentiation by O2 in a dose-dependent manner. By contrast, forced expression of HIF1alpha in normoxia using DMOG repressed Ngn3 expression and blocked beta-cell development. Finally, hypoxia requires hairy and enhancer of split (HES)1 expression to repress beta-cell differentiation. CONCLUSIONS These data demonstrate that beta-cell differentiation is controlled by pO2 through HIF1alpha. Modifying pO2 should now be tested in protocols aiming to differentiate beta-cells from embryonic stem cells.
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Affiliation(s)
- Mylène Heinis
- INSERM U845, Research Center Growth and Signalling, Université Paris Descartes, Hôpital Necker, Paris, France
| | - Marie-Thérèse Simon
- INSERM U845, Research Center Growth and Signalling, Université Paris Descartes, Hôpital Necker, Paris, France
| | - Karine Ilc
- Institute of Developmental Biology and Cancer Research, University of Nice, Nice, France
| | - Nathalie M. Mazure
- Institute of Developmental Biology and Cancer Research, University of Nice, Nice, France
| | - Jacques Pouysségur
- Institute of Developmental Biology and Cancer Research, University of Nice, Nice, France
| | - Raphael Scharfmann
- INSERM U845, Research Center Growth and Signalling, Université Paris Descartes, Hôpital Necker, Paris, France
| | - Bertrand Duvillié
- INSERM U845, Research Center Growth and Signalling, Université Paris Descartes, Hôpital Necker, Paris, France
- Corresponding author: Bertrand Duvillié,
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13
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Inhibition of oxygen sensors as a therapeutic strategy for ischaemic and inflammatory disease. Nat Rev Drug Discov 2009; 8:139-52. [PMID: 19165233 DOI: 10.1038/nrd2761] [Citation(s) in RCA: 273] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Cells in the human body need oxygen to function and survive, and severe deprivation of oxygen, as occurs in ischaemic heart disease and stroke, is a major cause of mortality. Nevertheless, other organisms, such as the fossorial mole rat or diving seals, have acquired the ability to survive in conditions of limited oxygen supply. Hypoxia tolerance also allows the heart to survive chronic oxygen shortage, and ischaemic preconditioning protects tissues against lethal hypoxia. The recent discovery of a new family of oxygen sensors--including prolyl hydroxylase domain-containing proteins 1-3 (PHD1-3)--has yielded exciting novel insights into how cells sense oxygen and keep oxygen supply and consumption in balance. Advances in understanding of the role of these oxygen sensors in hypoxia tolerance, ischaemic preconditioning and inflammation are creating new opportunities for pharmacological interventions for ischaemic and inflammatory diseases.
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14
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Fickova M, Pravdova E, Rondhal L, Uher M, Brtko J. In vitro antiproliferative and cytotoxic activities of novel kojic acid derivatives: 5-benzyloxy-2-selenocyanatomethyl- and 5-methoxy-2-selenocyanatomethyl-4-pyranone. J Appl Toxicol 2008; 28:554-9. [DOI: 10.1002/jat.1300] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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15
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Huang JK, Cui Y, Chen CH, Clampitt D, Lin CT, Wen L. Molecular cloning and functional expression of bovine deoxyhypusine hydroxylase cDNA and homologs. Protein Expr Purif 2007; 54:126-33. [PMID: 17391984 PMCID: PMC1945118 DOI: 10.1016/j.pep.2007.02.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2007] [Revised: 02/13/2007] [Accepted: 02/14/2007] [Indexed: 11/20/2022]
Abstract
Deoxyhypusine hydroxylase is the second of the two enzymes that catalyzes the maturation of eukaryotic initiation factor 5A (eIF5A). The mature eIF5A is the only known protein in eukaryotic cells that contains the unusual amino acid hypusine (N(epsilon)-(4-amino-2(R)-hydroxybutyl)lysine). Synthesis of hypusine is essential for the function of eIF5A in eukaryotic cell proliferation and survival. Here, we describe the cloning and characterization of bovine deoxyhypusine hydroxylase cDNA and its homologs. The deduced bovine deoxyhypusine hydroxylase protein is 87% identical to human enzyme and 45% identical to yeast enzyme. The overexpressed enzyme showed activity in catalyzing the hydroxylation of the deoxyhypusine residue in the eIF5A intermediate. An amino acid substitution from Glu 57 to Gly located at one of the four conserved His-Glu (HE) pairs, the potential metal coordination sites, resulted in severe reduction of deoxyhypusine hydroxylase activity. A deletion at the HEAT-repeats 1-3 resulted in complete losses of deoxyhypusine hydroxylase activity.
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Affiliation(s)
- Jenq-Kuen Huang
- Department of Chemistry, Western Illinois University, 1 University Circle, Macomb, IL 61455-1390
| | - Yalun Cui
- Department of Chemistry, Western Illinois University, 1 University Circle, Macomb, IL 61455-1390
| | - Chieh-Hua Chen
- Department of Chemistry, Western Illinois University, 1 University Circle, Macomb, IL 61455-1390
| | - Denae Clampitt
- Department of Chemistry, Western Illinois University, 1 University Circle, Macomb, IL 61455-1390
| | - Chi-Tsai Lin
- Institute of Bioscience and Biotechnology, National Taiwan Ocean University, Keelung, Taiwan 202
| | - Lisa Wen
- Department of Chemistry, Western Illinois University, 1 University Circle, Macomb, IL 61455-1390
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16
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Naughton JA, Bell A. Studies on cell-cycle synchronization in the asexual erythrocytic stages of Plasmodium falciparum. Parasitology 2006; 134:331-7. [PMID: 17034650 DOI: 10.1017/s0031182006001466] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2006] [Revised: 08/16/2006] [Accepted: 08/17/2006] [Indexed: 11/06/2022]
Abstract
Multiplication of Plasmodium parasites within human erythrocytes is essential to malarial disease. The cell-division cycle of this organism, however, is still poorly understood. In other eukaryotes, various techniques for (apparent) cell-cycle synchronization have been used to shed light on the mechanisms involved in cell division and its control. Thus far there is no technique for cell-cycle synchronization (as opposed to selection of parasites of a limited age-range) in Plasmodium. We therefore investigated the possibility that inhibitors of DNA synthesis, the mitotic spindle, or cell-cycle control elements (such as cyclin-dependent kinases) could be used to synchronize P. falciparum cultures to a particular cell-cycle phase. Surprisingly, most of these compounds did not cause a block at a specific phase. Three compounds, Hoechst 33342, roscovitine and L-mimosine, did block development at the trophozoite-schizont transition (S or G2 phase). The block caused by the latter 2 inhibitors was reversible, suggesting that they might be used as synchronizing agents. However, a consideration of the perturbing effects of inhibitors and problems with 'batch' synchronization techniques in general lead us to believe that any results obtained using roscovitine- or L-mimosine-treated parasites may not be reflective of the normal cell cycle.
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Affiliation(s)
- J A Naughton
- Department of Microbiology, Moyne Institute of Preventive Medicine, University of Dublin, Trinity College, Dublin 2, Ireland
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17
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McCombe D, Kubicki M, Witschi C, Williams J, Thompson EW. A collagen prolyl 4-hydroxylase inhibitor reduces adhesions after tendon injury. Clin Orthop Relat Res 2006; 451:251-6. [PMID: 16788402 DOI: 10.1097/01.blo.0000229281.60732.f8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Collagen synthesis inhibition potentially can reduce adhesion formation after tendon injury but also may affect cutaneous wound healing. We hypothesized that a novel orally administered collagen synthesis inhibitor (CPHI-I) would substantially reduce flexor tendon adhesions after injury, without any clinically important effect on cutaneous wound healing. The experiments were performed in a rat model with an in-continuity crush injury model in the rat hindfoot flexor tendon to provoke adhesion formation. Assays of dermal collagen production and the rate of healing of an excised wound were performed to assess cutaneous wound healing. Animals in the treatment groups received CPHI-I for 1, 2, or 6 weeks and were assessed at either 2 or 6 weeks. The work of flexion in the injured digit was reduced in the CPHI-I-treated animals compared with control animals, (0.188 J versus 0.0307 J at 2 weeks, and 0.0231 J versus 0.0331 J at 6 weeks) The cutaneous wound healing rate was similar in all animals, but dermal collagen synthesis was reduced in the treated animals. The CPHI-I seems to reduce tendon adhesion, and although collagen synthesis was reduced in cutaneous wounds, CPHI-I did not retard wound healing.
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Affiliation(s)
- D McCombe
- Bernard O'Brien Institute of Microsurgery, St Vincent's Hospital, University of Melbourne, Melbourne, Australia.
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18
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Li N, Yi F, Sundy CM, Chen L, Hilliker ML, Donley DK, Muldoon DB, Li PL. Expression and actions of HIF prolyl-4-hydroxylase in the rat kidneys. Am J Physiol Renal Physiol 2006; 292:F207-16. [PMID: 16885149 DOI: 10.1152/ajprenal.00457.2005] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Hypoxia inducible factor (HIF) prolyl-4-hydroxylase domain-containing proteins (PHDs) promote the degradation of HIF-1alpha. Because HIF-1alpha is highly expressed in the renal medulla and HIF-1alpha-targeted genes such as nitric oxide synthase, cyclooxygenase, and heme oxygenase are important in the regulation of renal medullary function, we hypothesized that PHD regulates HIF-1alpha levels in the renal medulla and, thereby, participates in the control of renal Na(+) excretion. Using real-time RT-PCR, Western blot, and immunohistochemical analyses, we have demonstrated that all three isoforms of PHD, PHD1, PHD2, and PHD3, are expressed in the kidneys and that PHD2 is the most abundant isoform. Regionally, all PHDs exhibited much higher levels in renal medulla than cortex. A furosemide-induced increase in renal medullary tissue Po(2) significantly decreased PHD levels in renal medulla, whereas hypoxia significantly increased mRNA levels of PHDs in cultured renal medullary interstitial cells, indicating that O(2) regulates PHDs. Functionally, the PHD inhibitor l-mimosine (l-Mim, 50 mg x kg(-1) x day(-1) i.p. for 2 wk) substantially upregulated HIF-1alpha expression in the kidneys, especially in the renal medulla, and remarkably enhanced (by >80%) the natriuretic response to renal perfusion pressure in Sprague-Dawley rats. Inhibition of HIF transcriptional activity by renal medullary transfection of HIF-1alpha decoy oligodeoxynucleotides attenuated l-Mim-induced enhancement of pressure natriuresis, which confirmed that HIF-1alpha mediated the effect of l-Mim. These results indicate that highly expressed PHDs in the renal medulla make an important contribution to the control of renal Na(+) excretion through regulation of HIF-1alpha and its targeted genes.
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Affiliation(s)
- Ningjun Li
- Dept. of Pharmacology & Toxicology, Medical College of Virginia Campus, Virginia Commonwealth Univ., PO Box 980613, Richmond, VA 23298, USA.
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Dong Z, Arnold RJ, Yang Y, Park MH, Hrncirova P, Mechref Y, Novotny MV, Zhang JT. Modulation of differentiation-related gene 1 expression by cell cycle blocker mimosine, revealed by proteomic analysis. Mol Cell Proteomics 2005; 4:993-1001. [PMID: 15855174 DOI: 10.1074/mcp.m500044-mcp200] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
L-mimosine, a plant amino acid, can reversibly block mammalian cells at late G1 phase and has been found to affect translation of mRNAs of the cyclin-dependent kinase inhibitor p27, eIF3a (eIF3 p170), and ribonucleotide reductase M2. The effect of mimosine on the expression of these genes may be essential for the G1 phase arrest. To determine additional genes that may be early respondents to the mimosine treatment, we performed two-dimensional gel electrophoretic analysis of [35S]methionine-labeled cell lysates followed by identification of the altered protein spots by LC-tandem mass spectrometry. In this study, the synthesis of two protein spots (MIP42 and MIP17) was found to be enhanced by mimosine, whereas the formation of another protein spot (MSP17) was severely blocked following mimosine treatment. These protein spots, MIP42, MIP17, and MSP17, were identified to be differentiation-related gene 1 (Drg-1; also called RTP, cap43, rit42, Ndrg-1, and PROXY-1), deoxyhypusine-containing eIF5A intermediate, and mature hypusine-containing eIF5A, respectively. The effect of mimosine on eIF5A maturation was due to inhibition of deoxyhypusine hydroxylase, the enzyme catalyzing the final step of hypusine biosynthesis in eIF5A. The mimosine-induced expression of Drg-1 was mainly attributable to increased transcription likely by the c-Jun/AP-1 transcription factor. Because induction of Drg-1 is an early event after mimosine treatment and is observed before a notable reduction in the steady-state level of mature eIF5A, eIF5A does not appear to be involved in the modulation of Drg-1 expression.
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Affiliation(s)
- Zizheng Dong
- Department of Pharmacology and Toxicology, Indiana University Cancer Center and Walther Oncology Center/Walther Cancer Institute, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
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20
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Martín-Puig S, Temes E, Olmos G, Jones DR, Aragonés J, Landázuri MO. Role of Iron (II)-2-Oxoglutarate-dependent Dioxygenases in the Generation of Hypoxia-induced Phosphatidic Acid through HIF-1/2 and von Hippel-Lindau-independent Mechanisms. J Biol Chem 2004; 279:9504-11. [PMID: 14681229 DOI: 10.1074/jbc.m310658200] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Hypoxia-inducible factors (HIF-1/HIF-2) govern the expression of critical genes for cellular adaptation to low oxygen tensions. We have previously reported that the intracellular level of phosphatidic acid (PA) rises in response to hypoxia (1% O(2)). In this report, we have explored whether components of the canonical HIF/von Hippel-Lindau (VHL) pathway are involved in the induction of PA. We found that hypoxia induces PA in a cell line constitutively expressing a stable version of HIF-1alpha. PA induction was also found in HIF-1alpha- and 2alpha-negative CHO Ka13 cells, as well as in HIF-beta-negative HepaC4 cells. These data indicate that HIF activity is neither sufficient nor necessary for oxygen-dependent PA accumulation. PA generation was also detected in cells deficient for the tumor suppressor VHL, indicating that the presence of VHL was not required for the induction of PA. Here we show that PA accumulation also occurs at moderate hypoxia (5% O(2)), although to a lesser extent to that seen at 1% O(2), revealing that PA is induced at the same hypoxia range required to activate HIF-1. Prolyl hydroxylases (PHD) and asparaginyl hydroxylase (FIH) belong to the iron (II) and 2-oxoglutarate-dependent dioxygenase family and have been proposed as oxygen sensors involved in the regulation of HIFs. Chemical inhibition of these activities by treatment with iron chelators or 2-oxoglutarate analogs also results in a marked PA accumulation similar to that observed in hypoxia. Together these data show that PA accumulation in response to hypoxia is both HIF-1/2- and VHL-independent and indicate a role of iron (II)-2-oxoglutarate-dependent dioxygenases in the oxygen-sensing mechanisms involved in hypoxia-driven phospholipid regulation.
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Affiliation(s)
- Silvia Martín-Puig
- Servicio de Inmunología, Hospital de la Princesa, Universidad Autónoma de Madrid, Diego de León 62, 28006 Madrid, Spain
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21
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Dong Z, Zhang JT. EIF3 p170, a mediator of mimosine effect on protein synthesis and cell cycle progression. Mol Biol Cell 2003; 14:3942-51. [PMID: 12972576 PMCID: PMC196594 DOI: 10.1091/mbc.e02-12-0784] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
l-Mimosine, a plant amino acid, can reversibly block mammalian cells at late G1 phase and has been suggested to affect translation of mRNAs such as p27, the CDK inhibitor. However, the mechanism of this effect is not known. Regulation of translation generally occurs at the initiation step that, in mammalian cells, is a complex process that requires multiple eukaryotic initiation factors (eIFs) and ribosome. The effects of mimosine on initiation factors or regulators consequently will influence translation initiation. P170, a putative subunit of eIF3, has been suggested to be nonessential for eIF3 function to form preinitiation complexes and it may function as a regulator for translation of a subset of mRNAs. In this article, we tested this hypothesis and investigated whether eIF3 p170 mediates mimosine effect on mRNA translation. We found that p170 translation was dramatically reduced by mimosine due to its iron-chelating function. The decreased expression of p170 by mimosine caused diminished de novo synthesis of tyrosinated alpha-tubulin and elevated translation of p27 before cell cycle arrest. These observations suggest that p170 is likely an early response gene to mimosine treatment and a mediator for mimosine effect on mRNA translation. The effect of p170 on the synthesis of tyrosinated alpha-tubulin and p27 in a reciprocal manner also suggests that p170 functions as a regulator for mRNA translation.
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Affiliation(s)
- Zizheng Dong
- Department of Pharmacology and Toxicology, Indiana University Cancer Center and Walther Oncology Center/Walther Cancer Institute, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
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22
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Warnecke C, Griethe W, Weidemann A, Jürgensen JS, Willam C, Bachmann S, Ivashchenko Y, Wagner I, Frei U, Wiesener M, Eckardt KU. Activation of the hypoxia-inducible factor-pathway and stimulation of angiogenesis by application of prolyl hydroxylase inhibitors. FASEB J 2003; 17:1186-8. [PMID: 12709400 DOI: 10.1096/fj.02-1062fje] [Citation(s) in RCA: 163] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Hypoxia-inducible transcription factors (HIF) mediate complex adaptations to reduced oxygen supply, including neoangiogenesis. Regulation of HIF occurs mainly through oxygen-dependent destruction of its alpha subunit. In the presence of oxygen, two HIFalpha prolyl residues undergo enzymatic hydroxylation, which is required for its proteasomal degradation. We therefore tested whether pharmacological activation of HIFalpha by hydroxylase inhibitors may provide a novel therapeutic strategy for the treatment of ischemic diseases. Three distinct prolyl 4-hydroxylase inhibitors-l-mimosine (L-Mim), ethyl 3,4-dihydroxybenzoate (3,4-DHB), and 6-chlor-3-hydroxychinolin-2-carbonic acid-N-carboxymethylamid (S956711)-demonstrated similar effects to hypoxia (0.5% O2) by inducing HIFalpha protein in human and rodent cells. L-Mim, S956711, and, less effectively, 3,4-DHB also induced HIF target genes in cultured cells, including glucose transporter 1 and vascular endothelial growth factor, as well as HIF-dependent reporter gene expression. Systemic administration of L-Mim and S956711 in rats led to HIFalpha induction in the kidney. In a sponge model for angiogenesis, repeated local injection of the inhibitors strongly increased invasion of highly vascularized tissue into the sponge centers. In conclusion, structurally distinct inhibitors of prolyl hydroxylation are capable of inducing HIFalpha and HIF target genes in vitro and in vivo and induce adaptive responses to hypoxia, including angiogenesis.
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Affiliation(s)
- Christina Warnecke
- Department of Nephrology and Medical Intensive Care, Charité, Campus Virchow Clinic, Augustenburger Platz 1, 13353 Berlin, Germany
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Caplice NM, Simari RD, Holmes DR. Molecular biology and gene transfer in atherosclerosis in the stenting era. INTERNATIONAL JOURNAL OF CARDIOVASCULAR INTERVENTIONS 2003; 2:141-152. [PMID: 12623583 DOI: 10.1080/acc.2.3.141.152] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Atherosclerosis is the major cause of death in the developed world. Understanding the pathogenesis of atherosclerosis has been a major challenge to cardiovascular research over the past several decades. During this period a number of advances in various scientific disciplines has increased our understanding of this disease. These include improved understanding of the structural and functional components of normal vessel wall and more recently the use of cell biology and molecular biology techniques to elucidate the pathogenesis of atherosclerosis. None of these advances has been more dramatic nor has potentially more far reaching consequences as the application of molecular biology and gene technology to the practice of cardiovascular medicine. These developments have already opened new and exciting areas of vascular research and may in the future provide for earlier identification of genetic predisposition to atherosclerosis, strategic planning of preventive therapy and more tailored pharmacologic approaches for established disease.
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Affiliation(s)
- Noel M Caplice
- Division of Cardiovascular Diseases, Mayo Clinic and Foundation, Rochester, MN
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Chekanov V, Mortada M, Maternowski M, Tchekanov G, Eisenstein R, Krum D, Akhtar M. Slowed progression or elimination of atherosclerosis by low-frequency electrical impulses. J Card Surg 2003; 18:47-58. [PMID: 12696767 DOI: 10.1046/j.1540-8191.2003.01910.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND In our previous investigations we showed that electrical impulses (EI) can prevent the development of atherosclerosis if they began simultaneously with high cholesterol diet (HCD) or in the early stages of atherosclerosis (after three weeks of HCD only). In this investigation we demonstrated the slow progression or elimination of atherosclerosis by low-frequency EI in case of moderate atherosclerosis (after eight weeks of HCD). METHODS Series I rabbits (control group) were fed HCD for eight weeks. Series II rabbits were fed HCD for eight weeks and were then switched to normal diet for eight weeks (no EI). Series III rabbits were fed HCD for eight weeks and then switched to a normal diet with simultaneous EI (applied near the abdominal aorta) for eight weeks (3 V, 30 single impulses per minute, 24 hours/day). After euthanization, the level of atherosclerosis, percentage of surface area involved in the atherosclerosis process, and an atherosclerosis score were calculated in the aortic arch, thoracic and abdominal aorta. RESULTS Statistically significant differences were seen in the level of atherosclerosis in the abdominal aorta between series III animals (0.4 +/- 0.2) and the other two groups: 1.5 +/- 0.4 in series I (HCD only), 1.2 +/- 0.3 in series II (HCD then normal diet). Gross examination of the surface also revealed statistically significant differences (p < 0.05) in the percentage of atherosclerosis between the control series I (30.1 +/- 4.1%) and series II (21.3 +/- 3.6%), compared with series III (5.5 +/- 5.4%). In addition, the atherosclerosis score was also significantly different: 45.8 +/- 3.9 in series I, 25.2 +/- 6.9 in series II, and 2.2 +/- 2.0 in series III (p < 0.05). CONCLUSION Our study showed that, when applied near the abdominal aorta, low-frequency electrical impulses decrease atherosclerotic deposition in the abdominal aorta.
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Affiliation(s)
- Valeri Chekanov
- Milwaukee Heart Institute, Heart Care Associates at Sinai Samaritan Medical Center/St. Luke's Medical Center, Milwaukee, Wisconsin 53201-0342, USA.
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Clement PMJ, Hanauske-Abel HM, Wolff EC, Kleinman HK, Park MH. The antifungal drug ciclopirox inhibits deoxyhypusine and proline hydroxylation, endothelial cell growth and angiogenesis in vitro. Int J Cancer 2002; 100:491-8. [PMID: 12115536 DOI: 10.1002/ijc.10515] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The hypusine biosynthetic steps represent novel targets for intervention in cell proliferation. Hypusine is a rare amino acid, formed posttranslationally in one cellular protein, eIF5A, and is essential for cell proliferation. Deoxyhypusine hydroxylase, the metalloenzyme catalyzing the final step in hypusine biosynthesis, and prolyl 4-hydroxylase, a non-heme iron enzyme critical for collagen processing, can be inhibited by small chelating molecules that target their essential metal atom. We examined the effects of 5 compounds (ciclopirox, deferiprone, deferoxamine, mimosine and 2,2'-dipyridyl) on these protein hydroxylases in HUVECs, on cell proliferation and on angiogenesis using 2 model assays: tube-like vessel formation on Matrigel and the chick aortic arch sprouting assay. These compounds inhibited cellular deoxyhypusine hydroxylase in a concentration-dependent manner, but their efficacy varied widely in the following order: ciclopirox--> deferoxamine-->2,2'-dipyridyl-->deferiprone-->mimosine (IC(50) 5-200 microM). Inhibition of DNA synthesis, following the same order (IC(50) 10-450 microM), correlated with G(1) arrest of the cell cycle. These compounds also inhibited proline hydroxylation and maturation of collagen in HUVECs and caused inhibition of angiogenesis in vitro. Of the compounds tested, ciclopirox was by far the most effective inhibitor of HUVEC proliferation and angiogenesis. The strong antiangiogenic activity of this readily available antifungal drug along with its antiproliferative effects suggests a new potential application for ciclopirox in the treatment of solid tumors.
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Affiliation(s)
- Paul M J Clement
- Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
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Hanauske-Abel HM, Popowicz A, Remotti H, Newfield RS, Levy J. Tyrosinemia I, a model for human diseases mediated by 2-oxoacid-utilizing dioxygenases: hepatotoxin suppression by NTBC does not normalize hepatic collagen metabolism. J Pediatr Gastroenterol Nutr 2002; 35:73-8. [PMID: 12142814 DOI: 10.1097/00005176-200207000-00016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
OBJECTIVES Medical treatment of tyrosinemia I relies on the herbicide NTBC [Orfadin 2-(2-nitro-4-trifluoromethylbenzoyl)-cyclohexane-1,3-dione], an inhibitor of plant and mammalian 2-oxoacid-utilizing dioxygenases with a collective catalytic cycle ('HAG' mechanism). We hypothesize that NTBC-treated tyrosinemia I is a human model for the pathogenic role of two major enzymes in this class, 4-hydroxyphenylpyruvate dioxygenase (4-HPPD; EC 1.13.11.27) and prolyl 4-hydroxylase (P4-H; E.C. 1.14.11.2), essential for tyrosine and collagen metabolism, respectively. METHODS In a patient with established tyrosinemia I, we monitored the in vivo activities of 4-HPPD and P4-H via five biomarkers before and during NTBC medication. Hypothesis testing at the molecular level was performed by computational modeling of NTBC binding to the crystal structure-derived active site of 4-HPPD, and then relating these findings to our experimental results and to known P4-H data. RESULTS NTBC rapidly normalized the biomarkers for 4-HPPD activity. However, those for P4-H activity remained uniformly elevated after one hundred days on NTBC, the PIIINP biomarker even increasing above its grossly abnormal, initial level. This selective enzyme inhibition despite a collective catalytic cycle is attributed to the conformation of NTBC, which only fits the active site of 4-HPPD, as confirmed by its crystal structure. CONCLUSIONS Normalization of hepatic collagen formation, highly desirable in all fibrotic liver diseases, is not achieved by NTBC in tyrosinemia I. By establishing the molecular cause for this failure, our results also establish a rational approach to identify inhibitors that achieve that goal, either by joint 4-HPPD / P-4H inhibition, or by inhibition of only P-4H.
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Affiliation(s)
- Hartmut M Hanauske-Abel
- Departments of Pediatrics and Pathology, New York-Presbyterian Hospital, Columbia and Cornell Campuses, Rockefeller University, New York, New York, USA.
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Chekanov VS, Mortada ME, Tchekanov GV, Maternowski MA, Eisenstein R, Pello N, Krum D, Akhtar M. Pathologic and histologic results of electrical impulses in a rabbit model of atherosclerosis: 24-hour versus 8-hour regimen. J Vasc Surg 2002; 35:554-62. [PMID: 11877706 DOI: 10.1067/mva.2002.121756] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE Low frequency electrical impulses (EIs) reduce new atherosclerotic plaque formation in previously diseased arteries and may reverse the extent of previous pathologic damage in these structures. METHODS A pacemaker was implanted on the left side of rabbit abdominal aortas, and an electrode was placed close to the other side of the aorta in the psoas major muscle. For the induction of atherosclerosis, the rabbits were placed on a high cholesterol diet (HCD) for 11 weeks. No EIs were applied to the control series I. In the experimental series, the rabbits were fed an HCD for 3 weeks, after which EIs were applied simultaneously with an HCD for 8 additional weeks (3V, 30 contractions per minute). Experimental series II had 24-hour/day EIs, and series III had 8-hour/day EIs. RESULTS The closer to the area where the EIs were applied, the more local severity increased (atherosclerosis level and surface area). In the control series, the severity of atherosclerosis in the lower aorta assessed with an arbitrary grading system was 1.75 +/- 0.5 (versus 1.5 +/- 0.57 with 8-hour/day EIs and 0.5 +/- 0.3 with 24-hour/day EIs). The involved surface area was 32.5% +/- 9.5% (versus 1.0% +/- 0.8% with 8-hour/day EIs and 0.75% +/- 0.95% with 24-hour/day EIs). CONCLUSION Both 24-hour/day and 8-hour/day EIs applied close to the abdominal aorta decreased the severity of atherosclerosis in rabbits placed on a HCD, but 24-hour/day EIs decreased the severity more extensively.
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Affiliation(s)
- Valeri S Chekanov
- Heart Care Associates, Milwaukee Heart Institute at Sinai Samaritan Medical Center, Milwaukee, WI, USA.
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Abstract
Kojic acid is a fungal metabolite commonly produced by many species of Aspergillus, Acetobacter, and Penicillium. The Aspergillus flavus group has traditionally been used in the production of a number of foods, including miso (soybean paste), shoyu (soy sauce), and sake. Kojic acid is widely used as a food additive for preventing enzymatic browning, and in cosmetic preparations as a skin-lightening or bleaching agent. Because kojic acid is often produced during the fermentation of historically used dietary staples, it has a long history of consumption. Various types of compounds, such as glucose, sucrose, acetate, ethanol, arabinose, and xylose, have been used as carbon sources for kojic acid production. Different Aspergillus species are known to produce variable amounts of kojic acid. The mechanism of action of kojic acid is well defined and it has been shown to act as a competitive and reversible inhibitor of animal and plant polyphenol oxidases, xanthine oxidase, and D- and some L-amino acid oxidases. The structure of kojic acid indicates a relatively simple route of metabolism much like dietary hexoses. Acute or subchronic toxicity resulting from an oral dose has not been reported, but convulsions may occur if kojic acid is injected. Results of mutagenicity studies are mixed, but in the in vivo mammalian dominant lethal assay, kojic acid was proven negative. Continuous administration of high doses of kojic acid in mice resulted in induction of thyroid adenomas in both sexes. Kojic acid reversibly affects thyroid function primarily by inhibiting iodine uptake, leading to decreases in T3 and T4 and increase in TSH. Increased TSH from pituitary gland in turn stimulates thyroid hyperplasia. Several lines of evidence indicate that the proliferative effects of kojic acid on thyroid are not related to a genotoxic pathway. The risk of functional inhibition of iodine uptake and its metabolism (organification) and thyroid tumor induction by kojic acid in humans appears to be extremely low. Based on the literature reviewed and discussed here, consumption of kojic acid at levels normally found in food does not present a concern for safety.
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Affiliation(s)
- G A Burdock
- Burdock and Associates, Inc., 622 Beachland Boulevard, Vero Beach, Florida 32963, USA.
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Wang S, Bray P, McCaffrey T, March K, Hempstead BL, Kraemer R. p75(NTR) mediates neurotrophin-induced apoptosis of vascular smooth muscle cells. THE AMERICAN JOURNAL OF PATHOLOGY 2000; 157:1247-58. [PMID: 11021829 PMCID: PMC1850174 DOI: 10.1016/s0002-9440(10)64640-8] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The development of atherosclerotic lesions results from aberrant cell migration, proliferation, and extracellular matrix production. In advanced lesions, however, cellular apoptosis, leading to lesion remodeling, predominates. During lesion formation, the neurotrophins and the neurotrophin receptor tyrosine kinases, trks B and C, are induced and mediate smooth muscle cell migration. Here we demonstrate that a second neurotrophin receptor, p75(NTR), is expressed by established human atherosclerotic lesions and late lesions that develop after balloon injury of the rat thoracic aorta. The p75(NTR), a member of the tumor necrosis factor/FAS receptor family, can modulate trk receptor function as well as initiate cell death when expressed in cells of the nervous system that lack kinase-active trk receptors. p75(NTR) expression colocalizes to neointimal cells, which express smooth muscle cell alpha-actin and are expressed by cultured human endarterectomy-derived cells (HEDC). Areas of the plaque expressing p75(NTR) demonstrate increased TUNEL positivity, and HEDC undergo apoptosis in response to the neurotrophins. Finally, neurotrophins also induced apoptosis of a smooth muscle cell line genetically manipulated to express p75(NTR), but lacking trk receptor expression. These studies identify the regulated expression of neurotrophins and p75(NTR) as an inducer of smooth muscle cell apoptosis in atherosclerotic lesions.
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MESH Headings
- Animals
- Apoptosis/physiology
- Arteriosclerosis/pathology
- Arteriosclerosis/physiopathology
- Cells, Cultured
- Humans
- In Situ Nick-End Labeling
- Male
- Mice
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/pathology
- Muscle, Smooth, Vascular/physiology
- Nerve Growth Factors/pharmacology
- Polysaccharides/physiology
- Rats
- Rats, Sprague-Dawley
- Receptor, Nerve Growth Factor/metabolism
- Receptor, Nerve Growth Factor/physiology
- Temperature
- Tissue Distribution
- Tunica Intima/metabolism
- Tunica Intima/pathology
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Affiliation(s)
- S Wang
- Departments of Pathology and Medicine, Joan and Sanford I. Weill Medical College of Cornell University, New York, New York, USA
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30
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McCaffrey TA, Du B, Fu C, Bray PJ, Sanborn TA, Deutsch E, Tarazona N, Shaknovitch A, Newman G, Patterson C, Bush HL. The expression of TGF-beta receptors in human atherosclerosis: evidence for acquired resistance to apoptosis due to receptor imbalance. J Mol Cell Cardiol 1999; 31:1627-42. [PMID: 10471347 DOI: 10.1006/jmcc.1999.0999] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The degree of cellularity in vascular lesions is determined by the balance between the migration and proliferation of cells relative to their rate of egress and apoptosis. Transforming growth factor-beta(1) can act as a potent antiproliferative and apoptotic factor for proliferating vascular cells. Our laboratory has previously identified cells cultured from human vascular lesions that are resistant to the antiproliferative effect of TGF-beta(1) due to an acquired mutation in the Type II receptor for TGF-beta(1). In the present studies, the expression of the Type I and II receptors in coronary and carotid atherosclerotic lesions was analysed by immunostaining, RT-PCR, and in situ RT-PCR. Levels of the Type I and Type II receptors varied widely within lesions, with the highest levels in the fibrous cap and at discrete foci within the lesion. Regions of smooth muscle-like cells (SMC) were commonly found that were Type I positive but Type II receptor negative. In 43 cell lines cultured from 126 human lesions, 84% of the lesion-derived cell (LDC) cultures exhibited functional resistance to the antiproliferative effect of TGF-beta(1). This resistance was conferred against TGF-beta(1), TGF-beta(2), and TGF- beta(3), but not interferon-gamma or mimosine. While normal SMC exhibited a four-fold increase in the rate of apoptosis after TGF- beta(1) treatment, most LDC were resistant to apoptosis in response to TGF-beta(1). Resistant cells exhibited selective loss of Type II receptor expression, and retroviral transfection of Type II receptor cDNA partially corrected the functional deficit. Thus, resistance to apoptosis may lead to the slow proliferation of resistant cell subsets, thereby contributing to the progression of atherosclerotic and restenotic lesions.
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Affiliation(s)
- T A McCaffrey
- Division of Hematology/Oncology, Weill Medical College of Cornell University, New York, NY 10021, USA
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31
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Laury-Kleintop LD, Gleason M, Tulenko TN. Expression of the heterogenous nuclear ribonucleoprotein complex K protein and the prolyl-4-hydroxylase alpha-subunit in atherosclerotic arterial smooth muscle cells. Biochem Biophys Res Commun 1999; 260:382-9. [PMID: 10403779 DOI: 10.1006/bbrc.1999.0923] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Smooth muscle cells (SMC) play a major role in the formation of atherosclerotic lesions found on major blood vessels. SMC proliferation, migration, and protein synthesis promote the progression of the early lesion, the fatty streak, into a complex myointimal fibrous plaque. To investigate altered gene expression in SMC during atherogenesis, we characterized differences between SMC from normal rabbits, rabbits fed a 2% cholesterol diet, and Watanabe Heritable Hyperlipidemic rabbits (WHHL). We detected and isolated a 501 bp cDNA fragment representing the A isoform of heterogenous nuclear ribonucleoprotein complex K (hnRNP-K) and a 281 bp cDNA fragment representing the prolyl-4-hydroxylase alpha-subunit (alphaPH) mRNAs. hn-RNP-K was upregulated in SMC from cholesterol-fed rabbits isolated in primary culture, as well as in SMC medial tissue from both the cholesterol-fed and WHHL rabbits. alphaPH was upregulated in SMC from the cholesterol-fed rabbits isolated in primary culture and in the tissue from WHHL rabbits. These data demonstrate genes consistent with increased proliferation and collagen production are upregulated in SMC during atherogenesis and may shed new light on gene expression changes and corresponding phenotype changes in SMC during atherogenesis.
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MESH Headings
- Animals
- Arteries/enzymology
- Arteries/metabolism
- Arteries/pathology
- Arteriosclerosis/enzymology
- Arteriosclerosis/metabolism
- Base Sequence
- Cells, Cultured
- Cloning, Molecular
- DNA, Complementary
- Heterogeneous-Nuclear Ribonucleoprotein K
- Male
- Molecular Sequence Data
- Muscle, Smooth, Vascular/enzymology
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- Procollagen-Proline Dioxygenase/genetics
- Procollagen-Proline Dioxygenase/metabolism
- Rabbits
- Reverse Transcriptase Polymerase Chain Reaction
- Ribonucleoproteins/genetics
- Ribonucleoproteins/metabolism
- Sequence Homology, Nucleic Acid
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Affiliation(s)
- L D Laury-Kleintop
- Department of Physiology, MCP-Hahnemann University, MCP-Hahnemann School of Medicine, 2900 Queen Lane, Philadelphia, Pennsylvania, 19129, USA.
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Ju H, Hao J, Zhao S, Dixon IM. Antiproliferative and antifibrotic effects of mimosine on adult cardiac fibroblasts. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1448:51-60. [PMID: 9824667 DOI: 10.1016/s0167-4889(98)00114-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Prolyl 4-hydroxylase catalyzes the hydroxylation of collagen pro-alpha chains for the deposition of cardiac collagen. The effect of prolyl 4-hydroxylase on synthesis and degradation of collagen was studied in cultured adult cardiac fibroblasts using mimosine, a prolyl 4-hydroxylase inhibitor. Mimosine inhibited [3H]thymidine incorporation in cultured fibroblasts in a dose-dependent manner (100-600 microM). Immunofluorescence in fibroblasts and biochemical detection of mature type I collagen in culture serum revealed a strong inhibition of synthesis and secretion of mature collagens, respectively, in the presence of 200 microM mimosine. Western blot analysis for procollagen was carried out in cultured fibroblasts, and 200 microM mimosine treatment was associated with increased intracellular accumulation of procollagen from 4.14+/-0.27 to 10. 19+/-0.37 (arbitrary units). Immunofluorescence studies confirmed a marked increase of intracellular procollagens in fibroblasts treated with mimosine, which suggests a loss of coordinated monomeric procollagen synthesis and secretion of triple helical mature collagens. Modest inhibition of collagen type I mRNA abundance was observed in mimosine-treated fibroblasts, whereas no effect was noted for mRNAs of collagen type III, alpha-prolyl 4-hydroxylase or beta-prolyl 4-hydroxylase when compared to untreated control values. Treatment of fibroblasts with 200 microM mimosine was associated with elevation of matrix metalloproteinase (MMP)-9 activity. The cytotoxicity of mimosine treatment was found minimal at the concentrations indicated above. Thus the antifibrotic effects induced by mimosine on cultured adult cardiac fibroblasts was associated with inhibition of prolyl 4-hydroxylase and diminished extracellular secretion of procollagen, despite the reactive elevation of intracellular procollagen synthesis. We suggest that specific inhibition of prolyl 4-hydroxylase may provide a novel therapeutic approach for the modulation of cardiac fibrosis.
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Affiliation(s)
- H Ju
- Molecular Cardiology Laboratory, Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, Faculty of Medicine, University of Manitoba, Winnipeg, Man. R2H 2A6, Canada
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33
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Andrus L, Szabo P, Grady RW, Hanauske AR, Huima-Byron T, Slowinska B, Zagulska S, Hanauske-Abel HM. Antiretroviral effects of deoxyhypusyl hydroxylase inhibitors: a hypusine-dependent host cell mechanism for replication of human immunodeficiency virus type 1 (HIV-1). Biochem Pharmacol 1998; 55:1807-18. [PMID: 9714299 DOI: 10.1016/s0006-2952(98)00053-7] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The HIV-1 protein Rev, critical for translation of incompletely spliced retroviral mRNAs encoding capsid elements, requires a host cell protein termed "eukaryotic initiation factor 5A" (eIF-5A). This is the only protein containing hypusine, a lysine-derived hydroxylated residue that determines its proposed bioactivity, the translation of a subset of cellular mRNAs controlling G1-to-S transit of the cell cycle. We postulated that inhibiting the hypusine-forming deoxyhypusyl hydroxylase (DOHH) should, by depleting eukaryotic initiation factor 5A, compromise Rev function and thus reduce HIV-1 multiplication. We now report that the alpha-hydroxypyridones, specifically mimosine, a natural product, and deferiprone, an experimental drug, inhibited deoxyhypusyl hydroxylase in T-lymphocytic and promonocytic cell lines and, in a concentration-dependent manner, suppressed replication of HIV-1. However, the alpha-hydroxypyridones did not affect the formation of unspliced or multiply spliced HIV-1 transcripts. Rather, these agents caused Rev-dependent incompletely spliced HIV-1 mRNA such as gag, but not cellular "housekeeping" mRNAs, to disappear from polysomes. Consequently, alpha-hydroxypyridone-mediated depletion of eIF-5A decreased biosynthesis of structural HIV-1 protein encoded by gag, measured as p24, whereas the induced formation of cellular protein like tumor necrosis factor alpha remained unaffected. By interfering with the translation of incompletely spliced retroviral mRNAs, these compounds restrict HIV-1 to the early, nongenerative phase of its reproductive cycle. In the inducibly HIV-1 expressing T-cell line ACH-2, the deoxyhypusyl hydroxylase inhibitors triggered extensive apoptosis, particularly of cells that actively produce HIV-1. Selective suppression of retroviral protein biosynthesis and preferential apoptosis of retrovirally infected cells by alpha-hydroxypyridones point to a novel mode of antiretroviral action.
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Affiliation(s)
- L Andrus
- The New York Blood Center, NY, USA
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34
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Rocnik EF, Chan BM, Pickering JG. Evidence for a role of collagen synthesis in arterial smooth muscle cell migration. J Clin Invest 1998; 101:1889-98. [PMID: 9576753 PMCID: PMC508775 DOI: 10.1172/jci1025] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Migration of smooth muscle cells (SMCs) and collagen synthesis by SMCs are central to the pathophysiology of vascular disease. Both processes can be induced shortly after vascular injury; however, a functional relationship between them has not been established. In this study, we determined if collagen synthesis was required for SMC migration, using ethyl-3,4-dihydroxybenzoate (EDHB), an inhibitor of prolyl-4-hydroxylase, and 3,4-DL-dehydroproline (DHP), a proline analogue, which we demonstrate inhibit collagen elaboration by porcine arterial SMCs. SMCs exposed to EDHB or DHP attached normally to collagen- and vitronectin-coated substrates; however, spreading on collagen but not vitronectin was inhibited. SMC migration speed, quantified by digital time-lapse video microscopy, was significantly and reversibly reduced by EDHB and DHP. Flow cytometry revealed that expression of beta1 integrins, through which SMCs interact with collagen, was unaffected by EDHB or DHP. However, both inhibitors prevented normal clustering of beta1 integrins on the surface of SMCs, consistent with a lack of appropriate matrix ligands for integrin engagement. Moreover, there was impaired recruitment of vinculin into focal adhesion complexes of spreading SMCs and disassembly of the smooth muscle alpha-actin-containing cytoskeleton. These findings suggest that de novo collagen synthesis plays a role in SMC migration and implicates a mechanism whereby newly synthesized collagen may be necessary to maintain the transcellular traction system required for effective locomotion.
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Affiliation(s)
- E F Rocnik
- John P. Robarts Research Institute, Vascular Biology Group, London Health Sciences Centre, London, Canada N6A 5K8
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35
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Kivirikko KI, Pihlajaniemi T. Collagen hydroxylases and the protein disulfide isomerase subunit of prolyl 4-hydroxylases. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 1998; 72:325-98. [PMID: 9559057 DOI: 10.1002/9780470123188.ch9] [Citation(s) in RCA: 100] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Prolyl 4-hydroxylases catalyze the formation of 4-hydroxyproline in collagens and other proteins with an appropriate collagen-like stretch of amino acid residues. The enzyme requires Fe(II), 2-oxoglutarate, molecular oxygen, and ascorbate. This review concentrates on recent progress toward understanding the detailed mechanism of 4-hydroxylase action, including: (a) occurrence and function of the enzyme in animals; (b) general molecular properties; (c) intracellular sites of hydroxylation; (d) peptide substrates and mechanistic roles of the cosubstrates; (e) insights into the development of antifibrotic drugs; (f) studies of the enzyme's subunits and their catalytic function; and (g) mutations that lead to Ehlers-Danlos Syndrome. An account of the regulation of collagen hydroxylase activities is also provided.
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Affiliation(s)
- K I Kivirikko
- Collagen Research Unit, Biocenter, University of Oulu, Finland
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36
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Kaiser M, Weyand CM, Björnsson J, Goronzy JJ. Platelet-derived growth factor, intimal hyperplasia, and ischemic complications in giant cell arteritis. ARTHRITIS AND RHEUMATISM 1998; 41:623-33. [PMID: 9550471 DOI: 10.1002/1529-0131(199804)41:4<623::aid-art9>3.0.co;2-6] [Citation(s) in RCA: 142] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVE To explore whether vasoocclusion in giant cell (temporal) arteritis (GCA) is related to intimal hyperplasia and in situ production of platelet-derived growth factor (PDGF). METHODS Temporal artery biopsy specimens from patients with GCA were analyzed for the presence of intimal hyperplasia. Expression of PDGF-A and PDGF-B was assessed by immunohistochemistry and digitized image analysis. RESULTS PDGF-A and PDGF-B were widely expressed in inflamed arteries. CD68+ macrophages, smooth muscle cells, and multinucleated giant cells produced PDGF, whereas hyperplastic intimal tissue did not. Arteries with marked luminal narrowing and those with no or minimal luminal narrowing differed in the extent and distribution of PDGF expression. Concentric intimal hyperplasia was associated with the accumulation of PDGF-A- and PDGF-B-producing CD68+ macrophages at the media-intima junction. PDGF+,CD68+ macrophages in close proximity to the internal elastic lamina frequently coproduced matrix metalloproteinase 2. Intimal hyperplasia of the temporal artery correlated with ischemic complications of GCA, such as ocular involvement, jaw claudication, and aortic arch syndrome. CONCLUSION Production of PDGF has a role in arterial occlusion in GCA. The excessive fibroproliferative response leading to luminal narrowing can be distinguished from the stenosing process in atherosclerosis and postangioplasty restenosis, suggesting that there are different response patterns to arterial injury. In GCA, macrophages at the media-intima border are the dominant source of PDGF. Since vasoocclusion is associated with a number of serious complications in GCA, inhibition of intimal proliferation should be a major goal of treatment.
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Affiliation(s)
- M Kaiser
- Mayo Clinic Foundation, Rochester, Minnesota 55905, USA
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37
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Abstract
Prolyl 4-hydroxylases (EC 1.14,11.2) catalyze the formation of 4-hydroxyproline in collagens and other proteins with collagen-like sequences. The vertebrate type I and type II enzymes are [alpha (I)]2 beta 2 and [alpha (II)]2 beta 2 tetramers, respectively, whereas the enzyme from the nematode Caenorhabditis elegans is an alpha beta dimer. The type I enzyme is the major form in most but not all vertebrate tissues. The catalytic properties of the various enzyme forms are highly similar, but there are distinct, although small, differences in K(m) values for various peptide substrates between the enzyme forms and major differences in Ki values for the competitive inhibitor, poly(L-proline). Prolyl 4-hydroxylase requires Fe2+, 2-oxoglutarate, O2 and ascorbate. Kinetic studies and theoretical considerations have led to elucidation of the reaction mechanism, and recent extensive site-directed mutagenesis studies have identified five critical residues at the cosubstrate binding sites. A number of compounds have been characterized that inhibit it competitively with respect to some of the cosubstrates, and three groups of suicide inactivators have also been identified. The beta subunit in all forms of prolyl 4-hydroxylase is identical to protein disulfide isomerase (PDI), a multifunctional polypeptide that also serves as a subunit in the microsomal triglyceride transfer protein, as a chaperone-like polypeptide that probably assists folding of a number of newly synthesized proteins, and in several other functions. The main role of the PDI polypeptide as a protein subunit is probably related to its chaperone function. Recent expression studies of recombinant human prolyl 4-hydroxylase subunits in a yeast have indicated that the formation of a stable enzyme tetramer in vivo requires coexpression of collagen polypeptide chains.
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McCaffrey TA, Du B, Consigli S, Szabo P, Bray PJ, Hartner L, Weksler BB, Sanborn TA, Bergman G, Bush HL. Genomic instability in the type II TGF-beta1 receptor gene in atherosclerotic and restenotic vascular cells. J Clin Invest 1997; 100:2182-8. [PMID: 9410894 PMCID: PMC508412 DOI: 10.1172/jci119754] [Citation(s) in RCA: 136] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Cells proliferating from human atherosclerotic lesions are resistant to the antiproliferative effect of TGF-beta1, a key factor in wound repair. DNA from human atherosclerotic and restenotic lesions was used to test the hypothesis that microsatellite instability leads to specific loss of the Type II receptor for TGF-beta1 (TbetaR-II), causing acquired resistance to TGF-beta1. High fidelity PCR and restriction analysis was adapted to analyze deletions in an A10 microsatellite within TbetaR-II. DNA from lesions, and cells grown from lesions, showed acquired 1 and 2 bp deletions in TbetaR-II, while microsatellites in the hMSH3 and hMSH6 genes, and hypermutable regions of p53 were unaffected. Sequencing confirmed that these deletions occurred principally in the replication error-prone A10 microsatellite region, though nonmicrosatellite mutations were observed. The mutations could be identified within specific patches of the lesion, while the surrounding tissue, or unaffected arteries, exhibited the wild-type genotype. This microsatellite deletion causes frameshift loss of receptor function, and thus, resistance to the antiproliferative and apoptotic effects of TGF-beta1. We propose that microsatellite instability in TbetaR-II disables growth inhibitory pathways, allowing monoclonal selection of a disease-prone cell type within some vascular lesions.
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Affiliation(s)
- T A McCaffrey
- Department of Medicine, Cornell University Medical College-The New York Hospital, New York 10021, USA.
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39
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Nagler A, Miao HQ, Aingorn H, Pines M, Genina O, Vlodavsky I. Inhibition of collagen synthesis, smooth muscle cell proliferation, and injury-induced intimal hyperplasia by halofuginone. Arterioscler Thromb Vasc Biol 1997; 17:194-202. [PMID: 9012656 DOI: 10.1161/01.atv.17.1.194] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Proliferation of vascular smooth muscle cells (SMCs) and accumulation of extracellular matrix (ECM) components within the arterial wall in response to local injury are important etiologic factors in vascular proliferative disorders such as arteriosclerosis and restenosis after angioplasty. Fibrillar and nonfibrillar collagens are major constituents of the ECM that modulate cell shape and proliferative responses and thereby contribute to the pathogenesis of intimal hyperplasia. Halofuginone, an anticoccidial quinoazolinone derivative, inhibits collagen type I gene expression. We investigated the effect of halofuginone on (1) proliferation of bovine aortic endothelial cells and SMCs derived from the same specimen and maintained in vitro, (2) ECM deposition and collagen type I synthesis and gene expression, and (3) injury-induced intimal hyperplasia in vivo. DNA synthesis and proliferation of vascular SMCs in response to serum or basic fibroblast growth factor were abrogated in the presence of as little as 0.1 microgram/mL halofuginone; this inhibition was reversible upon removal of the compound. Under the same conditions, halofuginone exerted a relatively small antiproliferative effect on the respective vascular endothelial cells. Halofuginone also inhibited the synthesis and deposition of ECM components by vascular SMCs as indicated both by a substantial reduction in the amount of sulfated proteoglycans and collagen type I synthesis and gene expression. Local administration of halofuginone in the rabbit ear model of crush injury-induced arterial intimal hyperplasia resulted in a 50% reduction in intimal thickening as measured by a morphometric analysis of the neointima/media ratio. The differential inhibitory effect of halofuginone on vascular SMCs versus endothelial cells, its inhibition of ECM deposition and collagen type I synthesis, and its ability to attenuate injury-induced intimal hyperplasia may place halofuginone alone or in combination with other antiproliferative compounds as a potential candidate for prevention of arterial stenosis and accelerated atherosclerosis.
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Affiliation(s)
- A Nagler
- Department of Bone Marrow Transplantation, Hadassah-Hebrew University Hospital, Jerusalem, Israel
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Csonga R, Ettmayer P, Auer M, Eckerskorn C, Eder J, Klier H. Evaluation of the metal ion requirement of the human deoxyhypusine hydroxylase from HeLa cells using a novel enzyme assay. FEBS Lett 1996; 380:209-14. [PMID: 8601426 DOI: 10.1016/0014-5793(96)00020-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Hypusine synthesis in the eukaryotic initiation factor 5A is a unique two-step posttranslational modification. After deoxyhypusine is generated by the deoxyhypusine synthase, the deoxyhypusine hydroxylase (EC 1.14.99.29) catalyzes the formation of mature hypusine. A rapid assay for monitoring the deoxyhypusine hydroxylase activity was established, employing the oxidative cleavage of the hypusyl residue and subsequent extraction of the generated aldehydes. As metal ion chelators have been reported to inhibit the deoxyhypusine hydroxylase, the mechanism of this inhibition and the effect of transition metal ions on enzyme activity were investigated. A ferric ion appears to be essential for enzymatic activity, the inhibition of which is entirely attributed to the metal ion binding capacity of the chelators.
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Affiliation(s)
- R Csonga
- Sandoz Research Institute, Department of Immunodermatology, Vienna, Austria
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41
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McCaffrey TA, Consigli S, Du B, Falcone DJ, Sanborn TA, Spokojny AM, Bush HL. Decreased type II/type I TGF-beta receptor ratio in cells derived from human atherosclerotic lesions. Conversion from an antiproliferative to profibrotic response to TGF-beta1. J Clin Invest 1995; 96:2667-75. [PMID: 8675633 PMCID: PMC185973 DOI: 10.1172/jci118333] [Citation(s) in RCA: 135] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Atherosclerosis and postangioplasty restenosis may result from abnormal wound healing. The present studies report that normal human smooth muscle cells are growth inhibited by TGF-beta1, a potent wound healing agent, and show little induction of collagen synthesis to TGF-beta1, yet cells grown from human vascular lesions are growth stimulated by TGF-beta1 and markedly increase collagen synthesis. Both cell types increase plasminogen activator inhibitor-1 production, switch actin phenotypes in response to TGF-beta1, and produce similar levels of TGF-beta activity. Membrane cross-linking of 125I-TGF-beta1 indicates that normal human smooth muscle cells express type I, II, and III receptors. The type II receptor is strikingly decreased in lesion cells, with little change in the type I or III receptors. RT-PCR confirmed that the type II TGF-beta1 receptor mRNA is reduced in lesion cells. Transfection of the type II receptor into lesion cells restores the growth inhibitory response to TGF-beta1, implying that signaling remains responsive. Because TGF-beta1 is overexpressed in fibroproliferative vascular lesions, receptor-variant cells would be allowed to grow in a slow, but uncontrolled fashion, while overproducing extracellular matrix components. This TGF-beta1 receptor dysfunction may be relevant for atherosclerosis, restenosis and related fibroproliferative diseases.
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MESH Headings
- Actins/biosynthesis
- Arteriosclerosis/metabolism
- Arteriosclerosis/pathology
- Base Sequence
- Cell Division/drug effects
- Coronary Disease/metabolism
- Coronary Disease/pathology
- Coronary Vessels/drug effects
- Coronary Vessels/metabolism
- Coronary Vessels/pathology
- DNA Primers
- Extracellular Matrix Proteins/biosynthesis
- Gene Expression/drug effects
- Humans
- Molecular Sequence Data
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- Plasminogen Activator Inhibitor 1/biosynthesis
- Polymerase Chain Reaction
- Protein Serine-Threonine Kinases
- Proteoglycans/biosynthesis
- Proteoglycans/metabolism
- RNA, Messenger/analysis
- RNA, Messenger/biosynthesis
- Receptor, Transforming Growth Factor-beta Type II
- Receptors, Transforming Growth Factor beta/biosynthesis
- Receptors, Transforming Growth Factor beta/metabolism
- Recombinant Proteins/biosynthesis
- Reference Values
- Transfection
- Transforming Growth Factor beta/biosynthesis
- Transforming Growth Factor beta/metabolism
- Transforming Growth Factor beta/pharmacology
- beta-Galactosidase/biosynthesis
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Affiliation(s)
- T A McCaffrey
- Department of Medicine, Division of Hematology/Oncology, Cornell University Medical College, New York Hospital, New York 10021, USA
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Joe YA, Wolff EC, Park MH. Cloning and expression of human deoxyhypusine synthase cDNA. Structure-function studies with the recombinant enzyme and mutant proteins. J Biol Chem 1995; 270:22386-92. [PMID: 7673224 DOI: 10.1074/jbc.270.38.22386] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Deoxyhypusine synthase catalyzes the first step in the post-translational formation of hypusine (N epsilon-(4-amino-2-hydroxybutyl)lysine). cDNA clones encoding deoxyhypusine synthase were isolated from a human HeLa cell library. Full-length cDNA clones encoding a 369-amino acid protein (calculated molecular mass of 40,970 Da) and a shorter cDNA clone that would potentially encode a protein with an internal deletion of 56 amino acids (Asp262-Ser317) were isolated. The deduced amino acid sequence of the human enzyme shows a high degree of identity to that of yeast deoxyhypusine synthase and to the known sequences of tryptic peptides from the rat and Neurospora crassa enzymes. The recombinant enzyme formed upon expression in Escherichia coli effectively catalyzed deoxyhypusine synthesis. Variant human recombinant proteins with (i) a truncation of 48 or 97 NH2-terminal amino acids, (ii) a truncation of 39 COOH-terminal amino acids, or (iii) an internal deletion (Asp262-Ser317) were inactive. A chimeric protein consisting of the complete human sequence and 16 amino acids of the yeast sequence (Gln197-Asn212, not present in the human enzyme) inserted between Glu193 and Gln194 exhibited moderate activity.
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Affiliation(s)
- Y A Joe
- Enzyme Chemistry Section, NIDR, National Institutes of Health, Bethesda, Maryland 20892-4330, USA
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Hanauske-Abel HM, Slowinska B, Zagulska S, Wilson RC, Staiano-Coico L, Hanauske AR, McCaffrey T, Szabo P. Detection of a sub-set of polysomal mRNAs associated with modulation of hypusine formation at the G1-S boundary. Proposal of a role for eIF-5A in onset of DNA replication. FEBS Lett 1995; 366:92-8. [PMID: 7789538 DOI: 10.1016/0014-5793(95)00493-s] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
S phase entry, i.e. start of DNA replication, is a crucial step in proliferation. Inhibition of S phase entry correlates with inhibition of hypusine formation, an event affecting only the eukaryotic initiation factor 5A (eIF-5A). Its hypusine-containing sequence was postulated to authorize polysomal utilization of specific transcripts for proteins necessary to enable DNA replication. Using mimosine to reversibly suppress the hypusine-forming deoxyhypusyl hydroxylase (E.C. 1.14.99.29) in cells while differentially displaying their polysomal versus non-polysomal mRNA populations, we report the detection and classification of several mRNA species that indeed disappear from and reappear at polysomes in concert with inhibition and disinhibition, respectively, of hypusine formation. Based on initial sequence data, two translationally controlled enzymes, both critical for proliferation, are identified as candicate products of such mRNAs, methionine adenosyltransferase (E.C. 2.5.1.6) and cytochrome-c oxidase (EC 1.9.3.1) subunit I. The existence of such putative hypusine-dependent messenger nucleic acids (hymns) provides the basis for a proposal on their molecular function in onset of multiplication.
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Affiliation(s)
- H M Hanauske-Abel
- Department of Pediatrics, Cornell University Medical College-The New York Hospital, NY 10031, USA
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