1
|
Kolac UK. Inhibition of mitochondrial fission and protein kinase R improves progesterone in placental stress. J Mol Endocrinol 2023; 71:e230059. [PMID: 37522854 DOI: 10.1530/jme-23-0059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Accepted: 07/31/2023] [Indexed: 08/01/2023]
Abstract
Placenta synthesizes hormones that play a vital role in adapting maternal physiology and supporting fetal growth. This study aimed to explore the link between progesterone, a key steroid hormone produced by placenta, and mitochondrial fission and protein kinase R through the use of chemical inhibition in trophoblasts subjected to endotoxin lipopolysaccharide and double-stranded RNA analog polyinosinic:polycytidylic acid stress. Expressions of protein kinase R, dynamin-related protein 1, mitochondrial fission protein 1, and heat shock protein 60 were determined by applying lipopolysaccharide and polyinosinic:polycytidylic acid to BeWo trophoblast cells. Next, cells were treated with protein kinase R inhibitor 2-aminopurine and mitochondrial division inhibitor 1 to examine changes in progesterone levels and expression levels of proteins and mRNAs involved in progesterone biosynthesis. Last, effect of 2-aminopurine on mitochondrial fission was determined by immunoblotting and quantitative PCR (qPCR). Mitochondrial structural changes were also examined by transmission electron microscopy. Lipopolysaccharide and polyinosinic:polycytidylic acid stimulation induced mitochondrial fission and activated protein kinase R but decreased heat shock protein 60 levels and progesterone synthesis. Chemical inhibition of mitochondrial fission elevated progesterone synthesis and protein and mRNA levels of genes involved in progesterone biosynthesis. Inhibition of protein kinase R with 2-aminopurine prevented lipopolysaccharide and polyinosinic:polycytidylic acid induced mitochondrial fission and increased progesterone biosynthesis. Use of chemical inhibitors to treat placental stress caused by pathogens has potential to stabilize the production of progesterone. The study reveals that inhibiting mitochondrial fragmentation and reducing activity of stress kinase protein kinase R in syncytiotrophoblasts leads to an increase in progesterone synthesis when exposed to lipopolysaccharide and polyinosinic:polycytidylic acid.
Collapse
Affiliation(s)
- Umut Kerem Kolac
- Department of Medical Biology, Faculty of Medicine, Aydin Adnan Menderes University, Aydin, Turkey
| |
Collapse
|
2
|
Faris A, Ibrahim IM, Al kamaly O, Saleh A, Elhallaoui M. Computer-Aided Drug Design of Novel Derivatives of 2-Amino-7,9-dihydro-8H-purin-8-one as Potent Pan-Janus JAK3 Inhibitors. Molecules 2023; 28:5914. [PMID: 37570884 PMCID: PMC10473238 DOI: 10.3390/molecules28155914] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 07/28/2023] [Accepted: 07/31/2023] [Indexed: 08/13/2023] Open
Abstract
Rheumatoid arthritis (RA) remains one of the most prevalent autoimmune diseases worldwide. Janus kinase 3 (JAK3) is an essential enzyme for treating autoimmune diseases, including RA. Molecular modeling techniques play a crucial role in the search for new drugs by reducing time delays. In this study, the 3D-QSAR approach is employed to predict new JAK3 inhibitors. Two robust models, both field-based with R2 = 0.93, R = 0.96, and Q2 = 87, and atom-based with R2 = 0.94, R = 0.97, and Q2 = 86, yielded good results by identifying groups that may readily direct their interaction. A reliable pharmacophore model, DHRRR1, was provided in this work to enable the clear characterization of chemical features, leading to the design of 13 inhibitors with their pIC50 values. The DHRRR1 model yielded a validation result with a ROC value of 0.87. Five promising inhibitors were selected for further study based on an ADMET analysis of their pharmacokinetic properties and covalent docking (CovDock). Compared to the FDA-approved drug tofacitinib, the pharmaceutical features, binding affinity and stability of the inhibitors were analyzed through CovDock, 300 ns molecular dynamics simulations, free energy binding calculations and ADMET predictions. The results show that the inhibitors have strong binding affinity, stability and favorable pharmaceutical properties. The newly predicted molecules, as JAK3 inhibitors for the treatment of RA, are promising candidates for use as drugs.
Collapse
Affiliation(s)
- Abdelmoujoud Faris
- LIMAS, Department of Chemical Sciences, Faculty of Sciences Dhar El Mahraz, Sidi Mohamed Ben Abdellah University, Fez 30000, Morocco;
| | - Ibrahim M. Ibrahim
- Biophysics Department, Faculty of Science, Cairo University, Cairo 12613, Egypt;
| | - Omkulthom Al kamaly
- Department of Pharmaceutical Sciences, College of Pharmacy, Princess Nourah Bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia; (O.A.k.); (A.S.)
| | - Asmaa Saleh
- Department of Pharmaceutical Sciences, College of Pharmacy, Princess Nourah Bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia; (O.A.k.); (A.S.)
| | - Menana Elhallaoui
- LIMAS, Department of Chemical Sciences, Faculty of Sciences Dhar El Mahraz, Sidi Mohamed Ben Abdellah University, Fez 30000, Morocco;
| |
Collapse
|
3
|
Zhang J, Zhang X, Li L, Bai L, Gao Y, Yang Y, Wang L, Qiao Y, Wang X, Xu JT. Activation of Double-Stranded RNA-Activated Protein Kinase in the Dorsal Root Ganglia and Spinal Dorsal Horn Regulates Neuropathic Pain Following Peripheral Nerve Injury in Rats. Neurotherapeutics 2022; 19:1381-1400. [PMID: 35655111 PMCID: PMC9587175 DOI: 10.1007/s13311-022-01255-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/25/2022] [Indexed: 10/18/2022] Open
Abstract
Double-stranded RNA (dsRNA)-activated kinase (PKR) is an important component in inflammation and immune dysfunction. However, the role of PKR in neuropathic pain remains unclear. Here, we showed that lumbar 5 spinal nerve ligation (SNL) led to a significant increase in the level of phosphorylated PKR (p-PKR) in both the dorsal root ganglia (DRG) and spinal dorsal horn. Images of double immunofluorescence staining revealed that p-PKR was expressed in myelinated A-fibers, unmyelinated C-fibers, and satellite glial cells in the DRG. In the dorsal horn, p-PKR was located in neuronal cells, astrocytes, and microglia. Data from behavioral tests showed that intrathecal (i.t.) injection of 2-aminopurine (2-AP), a specific inhibitor of PKR activation, and PKR siRNA prevented the reductions in PWT and PWL following SNL. Established neuropathic pain was also attenuated by i.t. injection of 2-AP and PKR siRNA, which started on day 7 after SNL. Prior repeated i.t. injections of PKR siRNA prevented the SNL-induced degradation of IκBα and IκBβ in the cytosol and the nuclear translocation of nuclear factor κB (NF-κB) p65 in both the DRG and dorsal horn. Moreover, the SNL-induced increase in interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) production was diminished by this treatment. Collectively, these results suggest that peripheral nerve injury-induced PKR activation via NF-κB signaling-regulated expression of proinflammatory cytokines in the DRG and dorsal horn contributes to the pathogenesis of neuropathic pain. Our findings suggest that pharmacologically targeting PKR might be an effective therapeutic strategy for the treatment of neuropathic pain.
Collapse
Affiliation(s)
- Jian Zhang
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, 100 Science Avenue, Zhengzhou, 450001, China
| | - Xuan Zhang
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, 100 Science Avenue, Zhengzhou, 450001, China
| | - Liren Li
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, 100 Science Avenue, Zhengzhou, 450001, China
| | - Liying Bai
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, 100 Science Avenue, Zhengzhou, 450001, China
- Department of Anesthesiology, Pain and Perioperative Medicine, The First Affiliated Hospital, Zhengzhou University, 1 Jianshe East Road, Zhengzhou, 450052, China
| | - Yan Gao
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, 100 Science Avenue, Zhengzhou, 450001, China
| | - Yin Yang
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, 100 Science Avenue, Zhengzhou, 450001, China
| | - Li Wang
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, 100 Science Avenue, Zhengzhou, 450001, China
| | - Yiming Qiao
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, 100 Science Avenue, Zhengzhou, 450001, China
| | - Xueli Wang
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, 100 Science Avenue, Zhengzhou, 450001, China
| | - Ji-Tian Xu
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, 100 Science Avenue, Zhengzhou, 450001, China.
- Neuroscience Research Institute, Zhengzhou University, 100 Science Avenue, Zhengzhou, 450001, China.
| |
Collapse
|
4
|
Mashiach D, Bacasen EM, Singh S, Kao T, Yaramada L, Mishail D, Singh S, Miller JH. Enhanced characterization of the thyA system for mutational analysis in Escherichia coli: Defining mutationally "hot" regions of the gene. Mutat Res 2021; 823:111754. [PMID: 34091127 DOI: 10.1016/j.mrfmmm.2021.111754] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 03/19/2021] [Accepted: 03/31/2021] [Indexed: 11/19/2022]
Abstract
We have extensively characterized base substitution mutations in the 795 base pair (bp) long E. coli thyA gene to define as many of the base substitution mutational sites that inactivate the gene as possible. The resulting catalog of mutational sites constitutes a system with up to 5 times as many sites for monitoring each of the six base substitution mutations as the widely used rpoB/Rifr system. We have defined 75 sites for the G:C -> A:T transition, 68 sites for the G:C -> T:A transversion, 53 sites for the G:C -> C:G transversion, 49 sites for the A:T -> G:C transition, 39 sites for the A:T -> T:A transversion, and 59 sites for the A:T -> C:G transversion. The system is thus comprised of 343 base substitution mutations at 232 different base pairs, all of which can be sequenced with a single primer pair. This allows for the examination of mutational spectra using a more detailed probe of known mutations, while still allowing one to compare the number of repeated occurrences at specific sites. We have examined several mutagens and mutators with this system, and show its utility by looking at the spectrum of cisplatin, that has a single hotspot, underscoring the value of having as large an array of sites as possible at which one can monitor repeat occurrences. To test for regions of the gene that might be hotspots for a number of mutagens, or "hot" (mutaphilic) regions, we have looked at the ratio of mutations per set of an equal number of mutational sites throughout the gene. The resulting graphs suggest that there are "hot" regions at intervals, and this may reflect aspects of secondary structures, of the higher order structure of the chromosome, or perhaps the nucleoid structure of the chromosome plus histone-like protein complexes.
Collapse
Affiliation(s)
- Daniel Mashiach
- Department of Microbiology, Immunology, and Molecular Genetics, and The Molecular Biology Institute, University of California, and the David Geffen School of Medicine, Los Angeles, CA 90095, United States
| | - Erin Mae Bacasen
- Department of Microbiology, Immunology, and Molecular Genetics, and The Molecular Biology Institute, University of California, and the David Geffen School of Medicine, Los Angeles, CA 90095, United States
| | - Sunjum Singh
- Department of Microbiology, Immunology, and Molecular Genetics, and The Molecular Biology Institute, University of California, and the David Geffen School of Medicine, Los Angeles, CA 90095, United States
| | - Timothy Kao
- Department of Microbiology, Immunology, and Molecular Genetics, and The Molecular Biology Institute, University of California, and the David Geffen School of Medicine, Los Angeles, CA 90095, United States
| | - Lekha Yaramada
- Department of Microbiology, Immunology, and Molecular Genetics, and The Molecular Biology Institute, University of California, and the David Geffen School of Medicine, Los Angeles, CA 90095, United States
| | - Daniel Mishail
- Department of Microbiology, Immunology, and Molecular Genetics, and The Molecular Biology Institute, University of California, and the David Geffen School of Medicine, Los Angeles, CA 90095, United States
| | - Summer Singh
- Department of Microbiology, Immunology, and Molecular Genetics, and The Molecular Biology Institute, University of California, and the David Geffen School of Medicine, Los Angeles, CA 90095, United States
| | - Jeffrey H Miller
- Department of Microbiology, Immunology, and Molecular Genetics, and The Molecular Biology Institute, University of California, and the David Geffen School of Medicine, Los Angeles, CA 90095, United States.
| |
Collapse
|
5
|
Stachelska-Wierzchowska A, Wierzchowski J, Górka M, Bzowska A, Stolarski R, Wielgus-Kutrowska B. Tricyclic Nucleobase Analogs and Their Ribosides as Substrates and Inhibitors of Purine-Nucleoside Phosphorylases III. Aminopurine Derivatives. Molecules 2020; 25:E681. [PMID: 32033464 PMCID: PMC7037862 DOI: 10.3390/molecules25030681] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 01/24/2020] [Accepted: 01/30/2020] [Indexed: 11/16/2022] Open
Abstract
Etheno-derivatives of 2-aminopurine, 2-aminopurine riboside, and 7-deazaadenosine (tubercidine) were prepared and purified using standard methods. 2-Aminopurine reacted with aqueous chloroacetaldehyde to give two products, both exhibiting substrate activity towards bacterial (E. coli) purine-nucleoside phosphorylase (PNP) in the reverse (synthetic) pathway. The major product of the chemical synthesis, identified as 1,N2-etheno-2-aminopurine, reacted slowly, while the second, minor, but highly fluorescent product, reacted rapidly. NMR analysis allowed identification of the minor product as N2,3-etheno-2-aminopurine, and its ribosylation product as N2,3-etheno-2-aminopurine-N2--D-riboside. Ribosylation of 1,N2-etheno-2-aminopurine led to analogous N2--d-riboside of this base. Both enzymatically produced ribosides were readily phosphorolysed by bacterial PNP to the respective bases. The reaction of 2-aminopurine-N9- -D-riboside with chloroacetaldehyde gave one major product, clearly distinct from that obtained from the enzymatic synthesis, which was not a substrate for PNP. A tri-cyclic 7-deazaadenosine (tubercidine) derivative was prepared in an analogous way and shown to be an effective inhibitor of the E. coli, but not of the mammalian enzyme. Fluorescent complexes of amino-purine analogs with E. coli PNP were observed.
Collapse
Affiliation(s)
| | - Jacek Wierzchowski
- Department of Physics and Biophysics, University of Warmia and Mazury in Olsztyn, 10-719 Olsztyn, Poland;
| | - Michał Górka
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 5 Pasteura St., 02-093 Warsaw, Poland; (M.G.); (A.B.); (R.S.)
- Biological and Chemical Research Centre, University of Warsaw, 101 Zwirki i Wigury St., 02-089 Warsaw, Poland
| | - Agnieszka Bzowska
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 5 Pasteura St., 02-093 Warsaw, Poland; (M.G.); (A.B.); (R.S.)
| | - Ryszard Stolarski
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 5 Pasteura St., 02-093 Warsaw, Poland; (M.G.); (A.B.); (R.S.)
| | - Beata Wielgus-Kutrowska
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 5 Pasteura St., 02-093 Warsaw, Poland; (M.G.); (A.B.); (R.S.)
| |
Collapse
|
6
|
Li C, Mo J, Shu LP, Wu XJ, Xu JW, Yang Y, He ZX. [Molecular Mechanisms of Apoptosis of Leukemia Cell Induced by Reovirus]. Sichuan Da Xue Xue Bao Yi Xue Ban 2019; 50:649-653. [PMID: 31762232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
OBJECTIVE To investigate the molecular mechanism of apoptosis of HL60 cells induced by oncolytic virus Reovirus type 3 (Reo3). METHODS HL60 cells were infected with Reo3 at different multiplicity of infection (MOI) with the uninfected HL60 cells as control group. After 48 h of infection, the activity of HL60 cells infected with virus at different MOI was detected by CCK8 method to investigate the influence of MOI to cell activity. Simultaneously, the apoptotic rate of HL60 cells was detected by flow cytometry, and the activation level of double-stranded RNA-dependent protein kinase (PKR) and the expression of apoptotic-related protein in HL60 cells were detected by Western blot. Before infection with Reo3 for 48 h, HL60 cells were treated with 2-aminopurine (2-AP), a specific inhibitor of PKR, for 24 h. Afterward, the apoptotic level and expression of apoptotic related proteins were detected. RESULTS Activity of HL60 cells was obviously inhibited after infected with Reo3 with a MOI of 1 for 48 h. The cell survival rate was (24.333±3.396)% and the apoptotic rate was (29.96±2.06)%. Both rates were all higher than those in the control group (P < 0.05). Western blot results showed that the expression levels of PKR, p-PKR, Bax, Caspase3 and cleaved Caspase3 in HL60 cells infected with Reo3 were higher than those in the control group (P < 0.05), while the expression level of Bcl-2 was lower (P < 0.05). Compared with the group without inhibitor, the apoptotic rate of HL60 cells pretreated with 2-AP decreased (P < 0.05), the phosphorylation level of PKR and the expression level of apoptotic-related protein also decreased (P < 0.05). CONCLUSION Oncolytic virus Reo3 could activate PKR in HL60 cells and thus induce apoptosis of HL60 cells.
Collapse
Affiliation(s)
- Chen Li
- Tissue Engineering and Stem Cell Research Center, School of Basic Medical Sciences, Guizhou Medicine University, Guiyang 550004, China
- Key Laboratory of Adult Stem Cell Translational Research, Chinese Academy of Medical Sciences, Guiyang 550004, China
| | - Jing Mo
- Tissue Engineering and Stem Cell Research Center, School of Basic Medical Sciences, Guizhou Medicine University, Guiyang 550004, China
- Key Laboratory of Adult Stem Cell Translational Research, Chinese Academy of Medical Sciences, Guiyang 550004, China
| | - Li-Ping Shu
- Tissue Engineering and Stem Cell Research Center, School of Basic Medical Sciences, Guizhou Medicine University, Guiyang 550004, China
- Key Laboratory of Adult Stem Cell Translational Research, Chinese Academy of Medical Sciences, Guiyang 550004, China
| | - Xi-Jun Wu
- Tissue Engineering and Stem Cell Research Center, School of Basic Medical Sciences, Guizhou Medicine University, Guiyang 550004, China
- Key Laboratory of Adult Stem Cell Translational Research, Chinese Academy of Medical Sciences, Guiyang 550004, China
| | - Jian-Wei Xu
- Tissue Engineering and Stem Cell Research Center, School of Basic Medical Sciences, Guizhou Medicine University, Guiyang 550004, China
- Key Laboratory of Adult Stem Cell Translational Research, Chinese Academy of Medical Sciences, Guiyang 550004, China
| | - Yan Yang
- Tissue Engineering and Stem Cell Research Center, School of Basic Medical Sciences, Guizhou Medicine University, Guiyang 550004, China
- Key Laboratory of Adult Stem Cell Translational Research, Chinese Academy of Medical Sciences, Guiyang 550004, China
| | - Zhi-Xu He
- Key Laboratory of Adult Stem Cell Translational Research, Chinese Academy of Medical Sciences, Guiyang 550004, China
- Department of Pediatrics, Affiliated Hospital of Zunyi Medical University, Zunyi 563003, China
| |
Collapse
|
7
|
Ruiz JC, Aldern KA, Beadle JR, Hartline CB, Kern ER, Hostetler KY. Synthesis and Antiviral Evaluation of Alkoxyalkyl Esters of Phosphonopropoxymethyl-Guanine and Phosphonopropoxymethyl-Diaminopurine. ACTA ACUST UNITED AC 2016; 17:89-95. [PMID: 17042330 DOI: 10.1177/095632020601700204] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Phosphonopropoxymethyl-guanine is the methylene phosphonate analogue of acyclovir. Although not highly active against HSV, 4–38 µM of phosphonopropoxymethyl-guanine has been reported to be active against human and murine cytomegalovirus. Recently we found that cido-fovir, when esterified with alkoxyalkyl moieties, showed greatly increased antiviral activity against cytomegalovirus, herpes simplex virus and orthopoxviruses, in vitro. The alkoxyalkyl esters of cidofovir are orally active in murine models of human and murine cytomegalovirus and orthopoxviruses in vivo. To see if the antiviral activity of phosphonopropoxymethyl-guanine, phosphonopropoxymethyl-diaminopurine and phosphonopropoxymethyl-N6-cyclopropyl-diaminopurine could be increased by this approach, we synthesized their hexadecyloxypropyl-and octadecyloxyethyl- esters and evaluated antiviral activity and cytotoxicity in cells infected with HSV-1 and HCMV, in vitro. Marked increases in antiviral activity were noted in the alkoxyalkyl esters of phosphonopropoxymethyl-guanine. Alkoxyalkyl esters of diaminop-urine and N6-cyclopropyl-diaminopurine showed slight increases in activity against HSV-1 and marked increases in activity against HCMV. The results suggest that esterification with alkoxyalkyl moieties may be a generally useful way to increase antiviral activity of nucleoside phosphonates.
Collapse
Affiliation(s)
- Jacqueline C Ruiz
- Department of Medicine, Division of Infectious Disease, University of California, San Diego, CA, USA
| | | | | | | | | | | |
Collapse
|
8
|
Mishra OP, Popov AV, Pietrofesa RA, Christofidou-Solomidou M. Gamma-irradiation produces active chlorine species (ACS) in physiological solutions: Secoisolariciresinol diglucoside (SDG) scavenges ACS - A novel mechanism of DNA radioprotection. Biochim Biophys Acta Gen Subj 2016; 1860:1884-97. [PMID: 27261092 PMCID: PMC5253237 DOI: 10.1016/j.bbagen.2016.05.037] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 05/13/2016] [Accepted: 05/26/2016] [Indexed: 11/28/2022]
Abstract
Background Secoisolariciresinol diglucoside (SDG), the main lignan in whole grain flaxseed, is a potent antioxidant and free radical scavenger with known radioprotective properties. However, the exact mechanism of SDG radioprotection is not well understood. The current study identified a novel mechanism of DNA radioprotection by SDG in physiological solutions by scavenging active chlorine species (ACS) and reducing chlorinated nucleobases. Methods The ACS scavenging activity of SDG was determined using two highly specific fluoroprobes: hypochlorite-specific 3′-(p-aminophenyl) fluorescein (APF) and hydroxyl radical-sensitive 3′-(p-hydroxyphenyl) fluorescein (HPF). Dopamine, an SDG structural analog, was used for proton 1H NMR studies to trap primary ACS radicals. Taurine N-chlorination was determined to demonstrate radiation-induced generation of hypochlorite, a secondary ACS. DNA protection was assessed by determining the extent of DNA fragmentation and plasmid DNA relaxation following exposure to ClO− and radiation. Purine base chlorination by ClO− and γ-radiation was determined by using 2-aminopurine (2-AP), a fluorescent analog of 6-aminopurine. Results: Chloride anions (Cl−) consumed >90% of hydroxyl radicals in physiological solutions produced by γ-radiation resulting in ACS formation, which was detected by 1H NMR. Importantly, SDG scavenged hypochlorite- and γ-radiation-induced ACS. In addition, SDG blunted ACS-induced fragmentation of calf thymus DNA and plasmid DNA relaxation. SDG treatment before or after ACS exposure decreased the ClO− or γ-radiation-induced chlorination of 2-AP. Exposure to γ-radiation resulted in increased taurine chlorination, indicative of ClO− generation. NMR studies revealed formation of primary ACS radicals (chlorine atoms (Cl•) and dichloro radical anions (Cl2−•)), which were trapped by SDG and its structural analog dopamine. Conclusion We demonstrate that γ-radiation induces the generation of ACS in physiological solutions. SDG treatment scavenged ACS and prevented ACS-induced DNA damage and chlorination of 2-aminopurine. This study identified a novel and unique mechanism of SDG radioprotection, through ACS scavenging, and supports the potential usefulness of SDG as a radioprotector and mitigator for radiation exposure as part of cancer therapy or accidental exposure.
Collapse
Affiliation(s)
- Om P Mishra
- Department of Medicine, Pulmonary, Allergy and Critical Care Division, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, United States.
| | - Anatoliy V Popov
- Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, United States.
| | - Ralph A Pietrofesa
- Department of Medicine, Pulmonary, Allergy and Critical Care Division, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, United States.
| | - Melpo Christofidou-Solomidou
- Department of Medicine, Pulmonary, Allergy and Critical Care Division, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, United States.
| |
Collapse
|
9
|
Zhou L, Zhang HW, Tao S, Bassit L, Whitaker T, McBrayer TR, Ehteshami M, Amiralaei S, Pradere U, Cho JH, Amblard F, Bobeck D, Detorio M, Coats SJ, Schinazi RF. β-D-2'-C-Methyl-2,6-diaminopurine Ribonucleoside Phosphoramidates are Potent and Selective Inhibitors of Hepatitis C Virus (HCV) and Are Bioconverted Intracellularly to Bioactive 2,6-Diaminopurine and Guanosine 5'-Triphosphate Forms. J Med Chem 2015; 58:3445-58. [PMID: 25849312 PMCID: PMC7714489 DOI: 10.1021/jm501874e] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The conversion of selected β-D-2,6-diaminopurine nucleosides (DAPNs) to their phosphoramidate prodrug (PD) substantially blocks the conversion to the G-analog allowing for the generation of two bioactive nucleoside triphosphates (NTPs) in human hepatocytes. A variety of 2'-C-methyl DAPN-PDs were prepared and evaluated for inhibition of HCV viral replication in Huh-7 cells, cytotoxicity in various cell lines, and cellular pharmacology in both Huh-7 and primary human liver cells. The DAPN-PDs were pan-genotypic, effective against various HCV resistant mutants, and resistant variants could not be selected. 2'-C-Me-DAPN-TP and 2'-C-Me-GTP were chain terminators for genotype 1b HCV-pol, and single nucleotide incorporation assays revealed that 2'-C-Me-DAPN-TP was incorporated opposite U. No cytotoxicity was observed with our DAPN-PD when tested up to 50 μM. A novel, DAPN-PD, 15c, has been selected for further evaluation because of its good virologic and toxicologic profile and its ability to deliver two active metabolites, potentially simplifying HCV treatment.
Collapse
Affiliation(s)
- Longhu Zhou
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, United States
| | - Hong-wang Zhang
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, United States
| | - Sijia Tao
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, United States
| | - Leda Bassit
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, United States
- Veterans Affairs Medical Center, Decatur, Georgia 30033, United States
| | - Tony Whitaker
- CoCrystal Pharma, Inc., Tucker, Georgia 30084, United States
| | - Tamara R. McBrayer
- Veterans Affairs Medical Center, Decatur, Georgia 30033, United States
- CoCrystal Pharma, Inc., Tucker, Georgia 30084, United States
| | - Maryam Ehteshami
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, United States
| | - Sheida Amiralaei
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, United States
| | - Ugo Pradere
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, United States
| | - Jong Hyun Cho
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, United States
| | - Franck Amblard
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, United States
- Veterans Affairs Medical Center, Decatur, Georgia 30033, United States
| | - Drew Bobeck
- CoCrystal Pharma, Inc., Tucker, Georgia 30084, United States
| | - Mervi Detorio
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, United States
- Veterans Affairs Medical Center, Decatur, Georgia 30033, United States
| | - Steven J. Coats
- CoCrystal Pharma, Inc., Tucker, Georgia 30084, United States
| | - Raymond F. Schinazi
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, United States
- Veterans Affairs Medical Center, Decatur, Georgia 30033, United States
| |
Collapse
|
10
|
Affiliation(s)
- S L Sacks
- Department of Medicine, University of British Columbia, Vancouver, Canada
| |
Collapse
|
11
|
Pan Y, Zheng M, Zhong L, Yang J, Zhou S, Qin Y, Xiang R, Chen Y, Yang SY. A Preclinical Evaluation of SKLB261, a Multikinase Inhibitor of EGFR/Src/VEGFR2, as a Therapeutic Agent against Pancreatic Cancer. Mol Cancer Ther 2014; 14:407-18. [PMID: 25519702 DOI: 10.1158/1535-7163.mct-14-0485] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Youli Pan
- State Key Laboratory of Biotherapy and Cancer Center/Collaborative Innovation Center of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan, China
| | - Mingwu Zheng
- State Key Laboratory of Biotherapy and Cancer Center/Collaborative Innovation Center of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan, China
| | - Lei Zhong
- State Key Laboratory of Biotherapy and Cancer Center/Collaborative Innovation Center of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan, China
| | - Jiao Yang
- State Key Laboratory of Biotherapy and Cancer Center/Collaborative Innovation Center of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan, China
| | - Shu Zhou
- State Key Laboratory of Biotherapy and Cancer Center/Collaborative Innovation Center of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan, China
| | - Ya Qin
- State Key Laboratory of Biotherapy and Cancer Center/Collaborative Innovation Center of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan, China
| | - Rong Xiang
- Department of Clinical Medicine, School of Medicine, Nankai University, Tianjin, China
| | - Yuzong Chen
- Bioinformatics and Drug Design Group, Department of Pharmacy, and Center for Computational Science and Engineering, National University of Singapore, Singapore
| | - Sheng-Yong Yang
- State Key Laboratory of Biotherapy and Cancer Center/Collaborative Innovation Center of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan, China.
| |
Collapse
|
12
|
Park S, Shim SM, Nam SH, Andera L, Suh N, Kim I. CGP74514A enhances TRAIL-induced apoptosis in breast cancer cells by reducing X-linked inhibitor of apoptosis protein. Anticancer Res 2014; 34:3557-3562. [PMID: 24982369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
BACKGROUND Despite the selectivity of Tumor necrosis factor Related Apoptosis-Inducing Ligand (TRAIL) for cancer cell killing activity, breast cancer cells are resistant to TRAIL-induced apoptosis for various reasons. MATERIALS AND METHODS From a functionally-characterized small-molecule dataset, CGP74514A was identified as a TRAIL sensitizer in MCF-7 breast cancer cells. Combination of sub-toxic dose of TRAIL with CGP74514A was evaluated in three TRAIL-resistant breast cancer cells, MCF-7, T47D and SK-BR-3. RESULTS In all tested cells, CGP74514A enhanced TRAIL sensitivity. Combination treatment triggered apoptotic events faster than single treatment. Regarding its mechanism of action, CGP74514A reduced cytosolic X-linked inhibitor of apoptosis protein (XIAP). Small interfering RNA-mediated knockdown experiments showed that reduction of XIAP is the reason of sensitization. CONCLUSION CGP74514A sensitized breast cancer cells to TRAIL via reduction of XIAP expression level.
Collapse
Affiliation(s)
- Sojung Park
- Asan Institute for Life Sciences, Asan Medical Center, Seoul, Republic of Korea
| | - Sang-Mi Shim
- Department of Biomedical Sciences, Seoul National University, Seoul, Republic of Korea
| | - Sang-Hee Nam
- Asan Institute for Life Sciences, Asan Medical Center, Seoul, Republic of Korea
| | - Ladislav Andera
- Institute of Molecular Genetics, Academy of Science of the Czech Republic, Prague, Czech Republic
| | - Nayoung Suh
- Asan Institute for Life Sciences, Asan Medical Center, Seoul, Republic of Korea Department of Medicine, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Inki Kim
- Asan Institute for Life Sciences, Asan Medical Center, Seoul, Republic of Korea Department of Medicine, University of Ulsan College of Medicine, Seoul, Republic of Korea Cell Dysfunction Research Center (CDRC), University of Ulsan College of Medicine, Seoul, Republic of Korea
| |
Collapse
|
13
|
Abstract
Obesity and metabolic diseases appear as clusters, often featuring high risk for insulin resistance and type 2 diabetes, and constitute a major global health problem with limited treatment options. Previous studies have shown that double-stranded RNA-dependent kinase, PKR, plays an important role in the nutrient/pathogen-sensing interface, and acts as a key modulator of chronic metabolic inflammation, insulin sensitivity, and glucose homeostasis in obesity. Recently, pathological PKR activation was also demonstrated in obese humans, strengthening its prospects as a potential drug target. Here, we investigate the use of two structurally distinct small-molecule inhibitors of PKR in the treatment of insulin resistance and type 2 diabetes in cells and in a mouse model of severe obesity and insulin resistance. Inhibition of PKR reduced stress-induced Jun NH2-terminal kinase activation and insulin receptor substrate 1 serine phosphorylation in vitro and in vivo. In addition, treatment with both PKR inhibitors reduced adipose tissue inflammation, improved insulin sensitivity, and improved glucose intolerance in mice after the establishment of obesity and insulin resistance. Our findings suggest that pharmacologically targeting PKR may be an effective therapeutic strategy for the treatment of insulin resistance and type 2 diabetes.
Collapse
|
14
|
Sharon D, Schümann M, MacLeod S, McPherson R, Chaurasiya S, Shaw A, Hitt MM. 2-aminopurine enhances the oncolytic activity of an E1b-deleted adenovirus in hepatocellular carcinoma cells. PLoS One 2013; 8:e65222. [PMID: 23750246 PMCID: PMC3672087 DOI: 10.1371/journal.pone.0065222] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 04/23/2013] [Indexed: 01/01/2023] Open
Abstract
Adenoviruses with deletions of viral genes have been extensively studied as potential cancer therapeutics. Although a high degree of cancer selectivity has been demonstrated with these conditionally replicating adenoviruses, low levels of virus replication can be detected in normal cells. Furthermore, these mutations were also found to reduce the activity of the replicating viruses in certain cancer cells. Recent studies have shown that co-administration of chemotherapeutic drugs may increase the activity of these viruses without affecting their specificity. We constructed an adenovirus with deletions of both the E1b and the VA-RNA genes and found that replication of this virus was selective for human hepatocellular carcinoma (HCC) cell lines when compared to normal cell lines. Furthermore, we show that 2-aminopurine (2′AP) treatment selectively enhanced virus replication and virus-mediated death of HCC cells. 2′AP did not compensate for the loss of VA-RNA activities, but rather the loss of an E1b-55K activity, such as the DNA damage response, suggesting that co-administration of 2′AP derivatives that block host DNA damage response, may increase the oncolytic activity of AdΔE1bΔVA without reducing its selectivity for HCC cells.
Collapse
Affiliation(s)
- David Sharon
- Department of Oncology, University of Alberta, Edmonton, Alberta, Canada
| | - Michael Schümann
- Institut für Virologie, Klinikum der Philipps-Universität Marburg, Marburg, Germany
| | - Sheena MacLeod
- Department of Oncology, University of Alberta, Edmonton, Alberta, Canada
| | - Robyn McPherson
- Department of Oncology, University of Alberta, Edmonton, Alberta, Canada
| | | | - Andrew Shaw
- Department of Oncology, University of Alberta, Edmonton, Alberta, Canada
| | - Mary M. Hitt
- Department of Oncology, University of Alberta, Edmonton, Alberta, Canada
- * E-mail:
| |
Collapse
|
15
|
Cunningham A, Griffiths P, Leone P, Mindel A, Patel R, Stanberry L, Whitley R. Current management and recommendations for access to antiviral therapy of herpes labialis. J Clin Virol 2012; 53:6-11. [PMID: 21889905 PMCID: PMC3423903 DOI: 10.1016/j.jcv.2011.08.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 08/01/2011] [Accepted: 08/02/2011] [Indexed: 11/19/2022]
Abstract
Herpes labialis is a common skin infective condition, worldwide, which is primarily caused by HSV-1. Recurrent episodes of herpes labialis, also known as cold sores, can be frequent, painful, long-lasting and disfiguring for infected patients. At present, there are two types of antivirals for the treatment of herpes labialis, topical and oral, which are available over the counter or as prescription-only. The aim of antiviral therapy is to block viral replication to enable shortening the duration of symptoms and to accelerate healing of the lesions associated with herpes labialis. This review examines the evidence for the effectiveness of current topical and oral antivirals in the management of recurrent episodes of herpes labialis. In most countries, oral antivirals for herpes labialis are available as prescription-only. However, in early 2010, the oral antiviral famciclovir was reclassified from prescription-only medicine to pharmacist-controlled status in New Zealand. The benefits and risks associated with moving an antiviral therapy for herpes labialis from prescription-only to pharmacist-controlled status are reviewed here, and the implications for patients, general physicians and pharmacists are considered.
Collapse
Affiliation(s)
- Anthony Cunningham
- Westmead Millennium Institute and University of Sydney, Westmead, NSW 2145, Australia
| | - Paul Griffiths
- Centre for Virology, University College London Medical School, Rowland Hill Street, London, NW3 2PF, UK
| | - Peter Leone
- Division of Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Adrian Mindel
- Sexually Transmitted Infections Research Centre, University of Sydney, Marian Villa, Westmead Hospital, NSW 2145, Australia
| | - Rajul Patel
- University of Southampton, Southampton, SO14 0YG, UK
| | - Lawrence Stanberry
- Department of Pediatrics, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
| | - Richard Whitley
- Department of Pediatrics, Microbiology, Medicine and Neurosurgery, University of Alabama at Birmingham, CHB 303, 1600 7th Avenue South, Birmingham, AL 35233, USA
| |
Collapse
|
16
|
Huang HL, Wu JL, Chen MHC, Hong JR. Aquatic birnavirus-induced ER stress-mediated death signaling contribute to downregulation of Bcl-2 family proteins in salmon embryo cells. PLoS One 2011; 6:e22935. [PMID: 21901118 PMCID: PMC3161983 DOI: 10.1371/journal.pone.0022935] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Accepted: 07/06/2011] [Indexed: 12/17/2022] Open
Abstract
Aquatic birnavirus induces mitochondria-mediated cell death, but whether connects to endoplasmic reticulum (ER) stress is still unknown. In this present, we characterized that IPNV infection triggers ER stress-mediated cell death via PKR/eIF2α phosphorylation signaling for regulating the Bcl-2 family protein expression in fish cells. The IPNV infection can induce ER stress as follows: (1) ER stress sensor ATF6 cleavaged; (2) ER stress marker GRP78 upregulation, and (3) PERK/eIF2α phosphorylation. Then, the IPNV-induced ER stress signals can induce the CHOP expression at early (6 h p.i.) and middle replication (12 h p.i.) stages. Moreover, IPNV-induced CHOP upregulation dramatically correlates to apparently downregulate the Bcl-2 family proteins, Bcl-2, Mcl-1 and Bcl-xL at middle replication stage (12 h p.i.) and produces mitochondria membrane potential (MMP) loss and cell death. Furthermore, with GRP78 synthesis inhibitor momitoxin (VT) and PKR inhibitor 2-aminopurine (2-AP) treatment for blocking GRP78 expression and eIF2α phosphorylation, PKR/PERK may involve in eIF2α phosphorylation/CHOP upregulation pathway that enhances the downstream regulators Bcl-2 family proteins expression and increased cell survival. Taken together, our results suggest that IPNV infection activates PKR/PERK/eIF2α ER stress signals for regulating downstream molecules CHOP upregulation and Bcl-2 family downregulation that led to induce mitochondria-mediated cell death in fish cells, which may provide new insight into RNA virus pathogenesis and disease.
Collapse
Affiliation(s)
- Hui Ling Huang
- Laboratory of Molecular Virology and Biotechnology, Institute of Biotechnology, National Cheng Kung University, Tainan, Taiwan
| | - Jen Leih Wu
- Laboratory of Marine Molecular Biology and Biotechnology, Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Mark Hung Chih Chen
- Bioluminescence in Life-image Laboratory, Institute of Biotechnology, Department of Biotechnology, Hungkuang University, Taichung, Taiwan
- * E-mail: (JRH); (MHCC)
| | - Jiann Ruey Hong
- Laboratory of Molecular Virology and Biotechnology, Institute of Biotechnology, National Cheng Kung University, Tainan, Taiwan
- * E-mail: (JRH); (MHCC)
| |
Collapse
|
17
|
Seidl B, Kalali B, Gerhard M, Ring J, Ollert M, Mempel M. Thymic stromal lymphopoietin induction by polyinosinic:polycytidylic acid in human keratinocytes is preferentially mediated through protein kinase R and retinoid-inducible gene I and not Toll-like receptor 3. J Allergy Clin Immunol 2009; 124:862-4; author reply 864-5. [PMID: 19767083 DOI: 10.1016/j.jaci.2009.07.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2009] [Accepted: 07/08/2009] [Indexed: 11/16/2022]
|
18
|
Downes CS, Ryan A, Johnson RT. Radiomimetic Cell Cycle Delay Induced by Tetranodecanoyl Phorbol Acetate is Enhanced by Caffeine and by the Protein Kinase Inhibitor 2-aminopurine. Int J Radiat Biol 2009; 61:63-8. [PMID: 1345933 DOI: 10.1080/09553009214550631] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The tumour promoter and protein kinase C agonist, 12-O-tetranodecanoyl-phorbol-13-acetate (TPA), has been reported to show a radiomimetic action because it transiently delays the passage of HeLa cells through the G2 phase, as do ionizing radiation and other DNA damaging agents. Caffeine is known to override the G2 delay imposed by DNA damage; it is shown here that caffeine does not override the radiomimetic delay imposed by TPA in HeLa, but instead enhances it, without affecting G2 progression in control cells. Most of the other agents which more specifically affect some of the diverse range of caffeine targets either do not affect G2 progression after TPA, or delay G2 progression in control cells and exert a further delay in the presence of TPA. The exception is 2-aminopurine, a protein kinase inhibitor which has been shown to have an action similar to that of caffeine is allowing progression of the cell cycle to mitosis after the inhibition of DNA synthesis, without affecting normal cycle progression through G2. This agent, like caffeine, also has the contrary action of retarding cycle progression after TPA. It is concluded that the G2 delays induced by ionizing radiation and by TPA operate by different mechanisms, which are modulated in opposite senses by mechanisms involving protein kinase inhibition.
Collapse
Affiliation(s)
- C S Downes
- Department of Zoology, University of Cambridge, UK
| | | | | |
Collapse
|
19
|
Abstract
OBJECTIVE Many cases of herpes simplex virus (HSV) infection occur through asymptomatic shedding from persons without evidence of clinical disease. This study explores whether famciclovir reduces HSV shedding in HSV-2 seropositive persons with or without a history of symptomatic genital herpes. STUDY DESIGN One hundred twenty-seven HSV-2 seropositive participants were randomly assigned to 42 days of famciclovir, followed by 14 days of washout and 42 days of placebo, or vice versa. All subjects swabbed the genital/perianal area; those with HSV-1 infection also swabbed the oral area daily for HSV DNA PCR. RESULTS Famciclovir reduced genital and oral HSV shedding from 11.4% of days during the placebo period to 4.7% of days during famciclovir therapy. The reduction was greater in participants with a history of genital herpes (74%) than in those without such a history (30%). In multivariate analyses, famciclovir protected against total (clinical and subclinical) genital shedding among persons with a clinical history of genital herpes (RR, 0.23; 95% CI, 0.15-0.35; P < 0.001). Among HSV-2 seropositive participants without a history of genital herpes, 60% had HSV detected in the genital area at least once during the study. Famciclovir therapy did not result in a statistically significant reduction in total HSV shedding in participants without a history of genital herpes. CONCLUSION Famciclovir therapy decreases genital HSV shedding in HSV-seropositive persons, especially those with a history of genital herpes. Overall, antiviral drugs may have varying effects on symptomatic and asymptomatic viral shedding, depending on the clinical history of the disease.
Collapse
Affiliation(s)
- Peter Leone
- University of North Carolina, Chapel Hill, NC 27599-7030, USA.
| | | | | | | | | |
Collapse
|
20
|
Zhao SQ, Feng WL, Zeng JM, Bai WJ, Wang XZ, Wen JP, Cao WX, Luo YP, Huang ZG. [Effect of targeted activation of protein kinase PKR on proliferation of leukemia cell line K562 and its mechanism]. Ai Zheng 2007; 26:1058-1063. [PMID: 17927873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
BACKGROUND & OBJECTIVE The bcr-abl fusion gene induced by reciprocal translocation of t(9; 22)(q34; q11) plays an important role in pathogenesis of chronic myeloid leukemia (CML). Using the strategy of activating double-stranded RNA (dsRNA)-dependent protein kinase (PKR) by the dsRNA formed between the CML-specific bcr/abl fusion gene mRNA and the exogenous recombinant antisense RNA, this study was to investigate the effect of the activated PKR on the proliferation of leukemia cell line K562, and explore its possible mechanisms. METHODS dsRNA analogue polyriboinosinic polyribocytidylic acid (PolyIC), retroviral vector containing 40 bp of bcr/abl fusion gene sequence (RV-40AS), RV-40AS and 2-aminopurine (2-AP), and retroviral vector containing green fluorescent protein sequence (RV-GFP) were transfected or infected into K562 cells respectively; ECV304 cells were used as control. Cell proliferation was determined by cell counting, MTT assay, and semisolid clone formation experiment. Cell cycle was analyzed by flow cytometry (FCM). The expression of PKR, phosphated PKR (p-PKR), eukaryotic initiation factor-2alpha (eIF2alpha), and phosphated eIF2alpha (p-eIF2alpha) was detected by Western blot. Total protein synthesis was studied by 3H-leucine incorporation. RESULTS polyIC inhibited the proliferation of K562 cells and ECV304 cells unspecifically, while RV-40AS only inhibited the proliferation of K562 cells specifically. 2-AP blocked the inhibitory effect of RV-40AS on the proliferation of K562 cells. The S phase proportion was significantly lower in polyIC-and RV-40AS-treated K562 cells than in untreated cells [(37.26+/-2.35)% and (31.48+/-3.65)% vs. (58.53+/-5.42)%, P<0.05], while the G0/G1 phase proportion was significantly higher in polyIC-and RV-40AS-treated cells than in untreated cells [(50.97+/-2.18)% and (57.47+/-3.61)% vs. (36.44+/-4.20)%, P<0.05]. The expression of p-PKR and p-eIF2alpha in polyIC-and RV-40AS-treated K562 cells and polyIC-treated ECV304 cells was obviously up-regulated. The total protein synthesis level was significantly lower in RV-40AS-treated K562 cells than in untreated K562 cells [(3.5+/-1.9) cpm/ng vs. (26.8+/-2.6) cpm/ng, P<0.05]. CONCLUSION Targeted activation of PKR could inhibit the proliferation of K562 cells through inhibiting protein synthesis, and arresting progression of cell cycle.
Collapse
Affiliation(s)
- Shi-Qiao Zhao
- Department of Clinical Hematology, Key Laboratory of Laboratory Medical Diagnostics of Ministry of Education, Chongqing Medical University, Chongqing, 400016, P. R. China
| | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Morishima H, Kajiwara K, Akiyama K, Yanagihara Y. Ligation of Toll-like receptor 3 differentially regulates M2 and M3 muscarinic receptor expression and function in human airway smooth muscle cells. Int Arch Allergy Immunol 2007; 145:163-74. [PMID: 17851256 DOI: 10.1159/000108141] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2006] [Accepted: 06/05/2007] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Viral infection causes asthma exacerbations and airway hyperreactivity. Toll-like receptor 3 (TLR3) recognizes double-stranded RNA (dsRNA) of viral or synthetic origin in a fashion different from protein kinase R (PKR). The aim of this study was to examine the expression and function of TLR3 in human airway smooth muscle (ASM) cells. METHODS Expression of TLR3 and muscarinic receptor (MR), histamine receptor (HR), and cysteinyl leukotriene receptor (CysLTR) subtypes was analyzed by quantitative real-time PCR, flow cytometry, or Western blotting. It was assessed whether ASM cells respond to polyinosinic-polycytidylic acid (poly I:C), a synthetic analog of dsRNA, with alterations in M2R, M3R, H1R, and CysLT1R expression. The function of these subtypes was evaluated by cholinergic regulation of forskolin-stimulated cyclic AMP accumulation or by mobilization of intracellular calcium upon stimulation. RESULTS ASM cells expressed TLR3 and PKR, and intracellular TLR3 expression was demonstrated. Poly I:C caused decreased M2R and increased M3R expression, without affecting H1R and CysLT1R expression. Poly I:C-treated cells showed decreased cholinergic inhibition of forskolin-stimulated cyclic AMP accumulation and enhanced calcium flux in response to acetylcholine, but not to histamine and LTD4. These modulating effects of poly I:C were reversed by chloroquine, but not by 2-aminopurine. CONCLUSIONS The data indicate that poly I:C internalized by ASM cells differentially regulates M2R and M3R expression and function by interacting with TLR3 rather than with PKR, suggesting that these changes may contribute to airway hyperreactivity.
Collapse
MESH Headings
- 2-Aminopurine/pharmacology
- Bronchial Hyperreactivity/physiopathology
- Calcium Signaling/drug effects
- Cells, Cultured/drug effects
- Cells, Cultured/metabolism
- Chloroquine/pharmacology
- Colforsin/pharmacology
- Cyclic AMP/physiology
- Gene Expression Regulation/drug effects
- Histamine/pharmacology
- Humans
- Leukotriene D4/pharmacology
- Membrane Proteins/biosynthesis
- Membrane Proteins/genetics
- Muscarinic Antagonists/pharmacology
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Poly I-C/pharmacology
- Receptor, Muscarinic M2/antagonists & inhibitors
- Receptor, Muscarinic M2/biosynthesis
- Receptor, Muscarinic M2/genetics
- Receptor, Muscarinic M3/antagonists & inhibitors
- Receptor, Muscarinic M3/biosynthesis
- Receptor, Muscarinic M3/genetics
- Receptors, Histamine H1/biosynthesis
- Receptors, Histamine H1/genetics
- Receptors, Leukotriene/biosynthesis
- Receptors, Leukotriene/genetics
- Signal Transduction/drug effects
- Toll-Like Receptor 3/physiology
- eIF-2 Kinase/physiology
Collapse
Affiliation(s)
- Hirotaka Morishima
- Clinical Research Center for Allergy and Rheumatology, National Hospital Organization, Sagamihara Hospital, Sagamihara, Japan
| | | | | | | |
Collapse
|
22
|
Cabanski M, Steinmüller M, Marsh LM, Surdziel E, Seeger W, Lohmeyer J. PKR regulates TLR2/TLR4-dependent signaling in murine alveolar macrophages. Am J Respir Cell Mol Biol 2007; 38:26-31. [PMID: 17690330 DOI: 10.1165/rcmb.2007-0010oc] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The double-stranded RNA (dsRNA)-activated serine/threonine kinase R (PKR) is well characterized as an essential component of the innate antiviral response. Recently, PKR has been implicated in Toll-like receptor (TLR) signal transduction in response to bacterial cell wall components. Its contribution to pulmonary immunity, however, has not yet been elucidated. In this report we investigated whether PKR is involved in TLR2/TLR4-mediated immune responses of primary alveolar macrophages (AM). We found that both TLR2 (Pam3CSK4) and TLR4 (LPS) ligands induced rapid phosphorylation of PKR. Moreover, this activation was strictly dependent on the functionality of the respective TLR. Pharmacologic inhibition of PKR activity using 2-aminopurine (2-AP) and PKR gene deletion was found to reduce the TLR2/TLR4-induced activation of the JNK signaling pathway (MKK4/JNK/c-Jun), but did not affect p38 and extracellular signal-regulated kinase 1/2 activation. Moreover, inhibition of PKR phosphorylation severely impaired TNF-alpha and IL-6 production by AM in response to LPS and Pam3CSK4. In addition, we found that PKR phosphorylation plays a major role in LPS- but not Pam3CSK4-induced activation of the p65 subunit of NF-kappaB. Collectively, these results indicate that functional PKR is critically involved in inflammatory responses of primary AM to gram-positive as well as gram-negative bacterial cell wall components.
Collapse
Affiliation(s)
- Maciej Cabanski
- University of Giessen Lung Center, Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine and Infectious Diseases, Justus-Liebig-University, Klinikstrasse 36, Giessen 35392, Germany.
| | | | | | | | | | | |
Collapse
|
23
|
Jacquelín DK, Martina MA, Argaraña CE, Barra JL. Plasmid expression of mutS, -L and/or -H gene in Escherichia coli dam cells results in strains that display reduced mutation frequency. Mutat Res 2007; 637:197-204. [PMID: 17727900 DOI: 10.1016/j.mrfmmm.2007.07.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2007] [Revised: 06/29/2007] [Accepted: 07/17/2007] [Indexed: 11/20/2022]
Abstract
Escherichia colidam cells have an active but non-directed mismatch repair system; therefore, assembly of MutSLH complex at a mismatched base pair can result in MutH-mediated cleavage of GATC sites in both DNA strands. Unpaired double-strand breaks on a fraction of the replication errors occurring in dam cells presumably cause cell death, selectively eliminating these putative mutants from the population. We show that E. colidam cells transformed with plasmids containing either the mutS, mutL or mutH gene display a mutation frequency three to eight times lower than that of the parental dam strain, due to increased mismatch-stimulated cell killing. Transformed strains are also more susceptible to killing by the base analogue 2-aminopurine. However, dam and dam transformed cells have similar duplication time, proportion of live/dead cells and morphology.
Collapse
Affiliation(s)
- Daniela K Jacquelín
- Centro de Investigaciones en Química Biológica de Córdoba, Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, X5000HUA, Córdoba, Argentina
| | | | | | | |
Collapse
|
24
|
Panos GZ, Lampropoulos KM, Angelousi AG, Charatsis GG, Falagas ME. Lamivudine and famciclovir treatment in HIV patients with acute hepatitis B virus infection and hepatitis B reactivation. J Clin Gastroenterol 2007; 41:222-3. [PMID: 17245225 DOI: 10.1097/01.mcg.0000212614.89584.32] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
|
25
|
Biswas S, Jennens L, Field HJ. The helicase primase inhibitor, BAY 57-1293 shows potent therapeutic antiviral activity superior to famciclovir in BALB/c mice infected with herpes simplex virus type 1. Antiviral Res 2006; 75:30-5. [PMID: 17175035 DOI: 10.1016/j.antiviral.2006.11.006] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2006] [Revised: 11/09/2006] [Accepted: 11/21/2006] [Indexed: 11/26/2022]
Abstract
BAY 57-1293 represents a new class of potent inhibitors of herpes simplex virus (HSV) that target the virus helicase primase complex. The present study was conducted using the zosteriform infection model in BALB/c mice. The helicase primase inhibitor, BAY 57-1293 was shown to be highly efficacious in this model. The beneficial effects of therapy were obtained rapidly (within 2 days) although the onset of treatment was delayed for 1 day after virus inoculation. The compound given orally, or intraperitoneally once per day at a dose of 15 mg/kg for 4 successive days was equally effective or superior to a much higher dose of famciclovir (1mg/ml, i.e. approximately 140-200mg/kg/day) given in the drinking water for 7 consecutive days, which, in our hands, is the most effective method for administering famciclovir to mice. In contrast to the vehicle-treated infected mice, all mice that received antiviral therapy looked normal and active with no mortality, no detectable loss of weight and no marked change in ear thickness. BAY 57-1293 and famciclovir reduced the virus titers in the skin to below the level of detection by days 3 and 7 post infection, respectively. In both BAY 57-1293 and famciclovir-treated mice, infectious virus titers in the ear pinna and brainstem remained below the level of detection. Consistent with these findings, BAY 57-1293 also showed a potent antiviral effect in an experiment involving a small number of severely immunocompromised athymic-nude BALB/c mice.
Collapse
Affiliation(s)
- Subhajit Biswas
- Centre for Veterinary Science, Cambridge University Veterinary School, Madingley Road, Cambridge, CB3 0ES, UK
| | | | | |
Collapse
|
26
|
Abstract
Herpes simplex virus is one of the most common causes of genital ulcer disease worldwide. Herpes simplex virus-2 is the more common cause of genital herpes, a chronic infection that is characterised by periodic reactivation, with the capacity to produce recurrent symptomatic disease in the host (e.g., vesicular eruption), as well as intermittent asymptomatic shedding. Relapsing episodes may be physically and psychologically distressing. Shedding accounts for the majority of cases of transmission of genital herpes to sexual partners. Pregnant women who are shedding may transmit the virus at the time of delivery, with severe and potentially fatal consequences to the baby. Famciclovir, a synthetic acyclic guanine derivative, is the prodrug of penciclovir, which demonstrates in vitro antiviral activity against various types of herpes virus, including herpes simplex virus-2. Its pharmacokinetics allow for administration in a convenient dosing regimen compared with acyclovir, which may improve compliance. Clinical studies have demonstrated its efficacy in the episodic treatment of relapses, with the most recent report demonstrating its efficacy and tolerance as a single-day treatment. It is also efficacious and well tolerated for the suppression of frequently recurring episodes. These results have been demonstrated in various patient populations, including immunocompetent patients and those infected with HIV. Famciclovir is well tolerated, with an adverse events profile similar to placebo.
Collapse
Affiliation(s)
- Donald C Vinh
- University of Manitoba, Infectious Diseases and Medical Microbiology, Section of Infectious Diseases, Department of Medicine, Department of Medical Microbiology, Winnipeg, Manitoba, R3E 0W3, Canada
| | | |
Collapse
|
27
|
Vandromme L, Legraverend M, Kreimerman S, Lozach O, Meijer L, Grierson DS. A Pd(0) based cross-coupling approach to the synthesis of 2-amidopurines and their evaluation as CDK inhibitors. Bioorg Med Chem 2006; 15:130-41. [PMID: 17064911 DOI: 10.1016/j.bmc.2006.10.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2006] [Revised: 09/27/2006] [Accepted: 10/04/2006] [Indexed: 11/16/2022]
Abstract
Two new series of 2-amido- and 2-aminocarbonylpurines have been synthesized using a Pd catalyst cross-coupling reaction either with amides or amines in the presence of CO. Moderate in vitro inhibitory activity against CDK1 and CDK5 was observed with IC(50) of 0.9muM for the most active compound (18c).
Collapse
Affiliation(s)
- Lucie Vandromme
- UMR 176, Institut Curie, Bât. 110-112, Centre Universitaire, 91405 Orsay, France
| | | | | | | | | | | |
Collapse
|
28
|
Campos CBL, Bédard PA, Linden R. Requirement of p38 stress-activated MAP kinase for cell death in the developing retina depends on the stage of cell differentiation. Neurochem Int 2006; 49:494-9. [PMID: 16782232 DOI: 10.1016/j.neuint.2006.03.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2006] [Accepted: 03/21/2006] [Indexed: 11/26/2022]
Abstract
The p38 members of the mitogen-activated protein kinase (MAPK) superfamily are activated by both environmental stress and endogenous signals, and may have either permissive or inhibitory roles upon both cell proliferation and cell death in the retina. We have previously shown that anisomycin, a protein synthesis inhibitor, and 2-aminopurine, a specific inhibitor of the double stranded-RNA dependent protein kinase, block apoptosis of ganglion cells induced by axotomy, and induce apoptosis of cells in the neuroblastic layer in developing rat retina. Using a specific inhibitor, we found that p38-stress activated MAP kinase is required for the death of post-mitotic cells induced by anisomycin, but not for the death of proliferating cells induced by 2-aminopurine, nor of axon-damaged retinal ganglion cells. We also show that p38 activation occurs either upstream of or parallel to the requirement for cyclic AMP to block apoptosis of post-mitotic cells, since the cyclic AMP-producing agent forskolin did not prevent p38 phosphorylation induced by anisomycin. Finally, the lack of immunostaining for phospho-p38 in apoptotic profiles suggests that p38 activation does not kill retinal cells directly, but more likely through the mediation of neighboring cells.
Collapse
Affiliation(s)
- Claudia B L Campos
- Instituto de Biofísica, Universidade Federal do Rio de Janeiro, CCS, Bloco G, Cidade Universitária, Rio de Janeiro, RJ 21949-900, Brazil
| | | | | |
Collapse
|
29
|
Hosoi T, Matsunami N, Nagahama T, Okuma Y, Ozawa K, Takizawa T, Nomura Y. 2-Aminopurine inhibits leptin receptor signal transduction. Eur J Pharmacol 2006; 553:61-6. [PMID: 17070518 DOI: 10.1016/j.ejphar.2006.09.044] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2006] [Revised: 09/13/2006] [Accepted: 09/18/2006] [Indexed: 10/24/2022]
Abstract
Leptin is an important circulating signal for the regulation of food intake and body weight. In the present study, we investigated the effect of 2-aminopurine (2-AP), an inhibitor of double-strand RNA-activated protein kinase (PKR), on leptin signal transduction. 2-AP dose-dependently inhibited the leptin-induced phosphorylation of signal transducer and activator of transcription 3 (STAT3), extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK) in HEK293 cells stably transfected with the Ob-Rb leptin receptor. On the other hand, we observed only slight inhibition of leptin-induced STAT3 activation by purine treatment, indicating that the inhibitory effect will be dramatically enhanced in the presence of an amino group. 2-AP did not inhibit PMA-induced ERK activation, indicating that the effect may be leptin-signal specific. The inhibitory effect of 2-AP was not mediated by newly synthesized protein because the inhibitory effect of 2-AP on leptin-induced STAT3 activation was not abrogated in the presence of the protein synthesis inhibitor cycloheximide. Interestingly, leptin did not induce PKR activation, suggesting that the effect of 2-AP on the leptin signal may be independent of PKR. Finally, 2-AP inhibited leptin-induced phosphorylation of the Ob-Rb leptin receptor. These results provide evidence of a novel action of 2-AP, i.e., inhibition of the activation of leptin signal transduction at the level of the Ob-Rb leptin receptor.
Collapse
Affiliation(s)
- Toru Hosoi
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | | | | | | | | | | | | |
Collapse
|
30
|
Yakovleva L, Lai J, Kool ET, Shuman S. Nonpolar nucleobase analogs illuminate requirements for site-specific DNA cleavage by vaccinia topoisomerase. J Biol Chem 2006; 281:35914-21. [PMID: 17005552 DOI: 10.1074/jbc.m608349200] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Vaccinia DNA topoisomerase forms a covalent DNA-(3'-phosphotyrosyl)-enzyme intermediate at a specific target site 5'-C(+5)C(+4)C(+3)T(+2)T(+1)p downward arrow N(-1) in duplex DNA. Here we study the effects of nonpolar pyrimidine isosteres difluorotoluene (F) and monofluorotoluene (D) and the nonpolar purine analog indole at individual positions of the scissile and nonscissile strands on the rate of single-turnover DNA transesterification and the cleavage-religation equilibrium. Comparison of the effects of nonpolar base substitution to the effects of abasic lesions reported previously allowed us to surmise the relative contributions of base-stacking and polar edge interactions to the DNA transesterification reactions. For example, the deleterious effects of eliminating the +2T base on the scissile strand were rectified by introducing the nonpolar F isostere, whereas the requirement for the +1T base was not elided by F substitution. We impute a role for +1T in recruiting the catalytic residue Lys-167 to the active site. Topoisomerase is especially sensitive to suppression of DNA cleavage upon elimination of the +4G and +3G bases of the nonscissile strand. Indole provided little or no gain of function relative to abasic lesions. Inosine substitutions for +4G and +3G had no effect on transesterification rate, implying that the guanine exocyclic amine is not a critical determinant of DNA cleavage. Prior studies of 2-aminopurine and 7-deazaguanine effects had shown that the O6 and N7 of guanine were also not critical. These findings suggest that either the topoisomerase makes functionally redundant contacts with polar atoms (likely via Tyr-136, a residue important for precleavage active site assembly) or that it relies on contacts to N1 or N3 of the purine ring. The cleavage-religation equilibrium is strongly skewed toward trapping of the covalent intermediate by elimination of the +1A base of the nonscissile strand; the reaction equilibrium is restored by +1 indole, signifying that base stacking flanking the nick is critical for the religation step. Our findings highlight base isosteres as valuable tools for the analysis of proteins that act on DNA in a site-specific manner.
Collapse
Affiliation(s)
- Lyudmila Yakovleva
- Molecular Biology Program, Sloan-Kettering Institute, New York, New York 10021, USA
| | | | | | | |
Collapse
|
31
|
Edwards MR, Hewson CA, Laza-Stanca V, Lau HTH, Mukaida N, Hershenson MB, Johnston SL. Protein kinase R, IkappaB kinase-beta and NF-kappaB are required for human rhinovirus induced pro-inflammatory cytokine production in bronchial epithelial cells. Mol Immunol 2006; 44:1587-97. [PMID: 16989899 DOI: 10.1016/j.molimm.2006.08.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2006] [Accepted: 08/11/2006] [Indexed: 10/24/2022]
Abstract
Rhinovirus infections cause the majority of acute exacerbations of airway diseases such as asthma and chronic obstructive pulmonary disease, with increased pro-inflammatory cytokine production by infected bronchial epithelial cells contributing to disease pathogenesis. Theses diseases are a huge cause of morbidity worldwide, and contribute a major economic burden to healthcare costs. Current steroid based treatments are only partially efficient at controlling virus induced inflammation, which remains an unmet therapeutic goal. Although NF-kappaB has been implicated, the precise mechanisms of rhinovirus induction of pro-inflammatory gene expression in bronchial epithelial cells are unclear. We hypothesised that rhinovirus replication and generation of dsRNA was an important process of pro-inflammatory cytokine induction. Using pharmalogical (2-aminopurine and a new small molecule inhibitor) and genetic inhibition of the dsRNA binding kinase protein kinase R, striking inhibition of dsRNA (polyrIC) and rhinovirus induced CCL5, CXCL8 and IL-6 protein was observed. Using confocal microscopy, rhinovirus induced protein kinase R phosphorylation co-located with NF-kappaB p65 nuclear translocation. Focusing on CXCL8, both rhinovirus infection and dsRNA treatment required IkappaB kinase-beta for induction of CXCL8. Analysis of cis-acting sites in the CXCL8 promoter revealed that both rhinovirus infection and dsRNA treatment upregulated CXCL8 promoter activation via NF-kappaB and NF-IL6 binding sites. Together, the results demonstrate the importance of dsRNA in induction of pro-inflammatory cytokines by rhinoviruses, and suggest that protein kinase R is involved in NF-kappaB mediated gene transcription of pro-inflammatory cytokines via IkappaB kinase-beta. These molecules regulating rhinovirus induction of inflammation represent therapeutic targets.
Collapse
Affiliation(s)
- Michael R Edwards
- Department of Respiratory Medicine, National Heart Lung Institute and Wright Fleming Institute of Infection and Immunity, Imperial College London, Norfolk Place, London W2 1PG, UK.
| | | | | | | | | | | | | |
Collapse
|
32
|
Seki M, Nakagawa T, Seki T, Kato G, Tada S, Takahashi Y, Yoshimura A, Kobayashi T, Aoki A, Otsuki M, Habermann FA, Tanabe H, Ishii Y, Enomoto T. Bloom helicase and DNA topoisomerase IIIalpha are involved in the dissolution of sister chromatids. Mol Cell Biol 2006; 26:6299-307. [PMID: 16880537 PMCID: PMC1592785 DOI: 10.1128/mcb.00702-06] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bloom's syndrome (BS) is an autosomal disorder characterized by predisposition to a wide variety of cancers. The gene product whose mutation leads to BS is the RecQ family helicase BLM, which forms a complex with DNA topoisomerase IIIalpha (Top3alpha). However, the physiological relevance of the interaction between BLM and Top3alpha within the cell remains unclear. We show here that Top3alpha depletion causes accumulation of cells in G2 phase, enlargement of nuclei, and chromosome gaps and breaks that occur at the same position in sister chromatids. The transition from metaphase to anaphase is also inhibited. All of these phenomena except cell lethality are suppressed by BLM gene disruption. Taken together with the biochemical properties of BLM and Top3alpha, these data indicate that BLM and Top3alpha execute the dissolution of sister chromatids.
Collapse
Affiliation(s)
- Masayuki Seki
- Molecular Cell Biology Laboratory, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba 6-3, Aramaki, Aoba-ku, Sendai 980-8578, Japan.
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Abstract
Black willow (Salix nigra Marsh.) is the largest and only commercially important willow species in North America. It is a candidate for phytoremediation of polluted soils because it is fast-growing and thrives on floodplains throughout eastern USA. Our objective was to develop a protocol for the in vitro regeneration of black willow plants that could serve as target material for gene transformation. Unexpanded inflorescence explants were excised from dormant buds collected from three source trees and cultured on woody plant medium (WPM) supplemented with one of: (1) 0.1 mg l(-1) thidiazuron (TDZ); (2) 0.5 mg l(-1) 6-benzoaminopurine (BAP); or (3) 1 mg l(-1) BAP. All plant growth regulator (PGR) treatments induced direct adventitious bud formation from the genotypes. The percentage of explants producing buds ranged from 20 to 92%, depending on genotype and treatment. Although most of the TDZ-treated inflorescences produced buds, these buds failed to elongate into shoots. Buds on explants treated with BAP elongated into shoots that were easily rooted in vitro and further established in potting mix in high humidity. The PGR treatments significantly affected shoot regeneration frequency (P < 0.01). The highest shoot regeneration frequency (36%) was achieved with Genotype 3 cultured on 0.5 mg l(-1) BAP. Mean number of shoots per explant varied from one to five. The ability of black willow inflorescences to produce adventitious shoots makes them potential targets for Agrobacterium-mediated transformation with heavy-metal-resistant genes for phytoremediation.
Collapse
Affiliation(s)
- Satu Lyyra
- Daniel B. Warnell School of Forest Resources, University of Georgia, Athens, GA 30602, USA.
| | | | | |
Collapse
|
34
|
|
35
|
Fischer JM, Robbins SB, Kannamkumarath SS, Al-Zoughool M, Stringer SL, Talaska G, Caruso JA, Stambrook PJ, Stringer JR. Exposure of mice to arsenic and/or benzo[a]pyrene does not increase the frequency of Aprt-deficient cells recovered from explanted skin of Aprt heterozygous mice. Environ Mol Mutagen 2006; 47:334-44. [PMID: 16649189 DOI: 10.1002/em.20212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Exposure to inorganic arsenic in drinking water is linked to cancer in humans, but the mechanism of arsenic-induced cancer is not clear. Arsenic is not a powerful point mutagen, but can cause chromosome malsegregation and mitotic recombination, two events that can cause loss of tumor suppressor alleles and thereby contribute to the evolution of cancerous cells. To determine whether arsenic increases the frequency of allele loss due to either malsegregation or mitotic recombination in vivo, Aprt(+/-) hybrid mice were exposed to sodium arsenite (10 mg/L) in their drinking water for 10 weeks. To determine whether arsenic enhances the action of a known mutagen, half of the arsenic-treated mice were exposed to benzo[a]pyrene (BaP) for 8 weeks by skin painting (500 nmoles/week). Cells were taken from painted dorsal skin and cultured in the presence of 2,6-diaminopurine (DAP), to select colonies lacking adenosine phosphoribosyl transferase (Aprt) activity. The frequency of DAP-resistant (DAP(r)) colonies varied substantially within the treatment groups, but there was no significant difference between the groups. Analysis of DNA from DAP(r) colonies suggested that mitotic recombination contributed to the loss of wild-type Aprt allele. Whether arsenic or BaP enhanced or diminished the frequency of this process could not be deduced from these data.
Collapse
Affiliation(s)
- Jared M Fischer
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, Ohio, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Matic I, Ekiert D, Radman M, Kohiyama M. Generation of DNA-free Escherichia coli cells by 2-aminopurine requires mismatch repair and nonmethylated DNA. J Bacteriol 2006; 188:339-42. [PMID: 16352851 PMCID: PMC1317583 DOI: 10.1128/jb.188.1.339-342.2006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Undirected mismatch repair initiated by the incorporation of the base analog 2-aminopurine kills DNA-methylation-deficient Escherichia coli dam cells by DNA double-strand breakage. Subsequently, the chromosomal DNA is totally degraded, resulting in DNA-free cells.
Collapse
Affiliation(s)
- Ivan Matic
- INSERM U571, Faculté de Médecine, Université Paris V, 156 rue Vaugirard, 75730 Paris Cedex 15, France.
| | | | | | | |
Collapse
|
37
|
Abstract
Genital herpes, an incurable viral disease that can have a devastating impact on affected patients, is a serious public health concern affecting one in four Americans. Episodic treatment with nucleoside analogs for 3-5 days is the most common method of treatment; however, since maximum viral replication occurs within 24 hours after the onset of symptoms, single-day patient-initiated episodic treatment may be a better option. A recent study evaluated the effectiveness of patient-initiated single-day famciclovir versus placebo in the treatment of genital herpes and found that single-day famciclovir decreased healing time and the duration of pain and other symptoms, and increased the proportion of patients who did not progress to a full outbreak. Compared with previous studies, the results of single-day therapy are similar to or better than the results of conventional therapies of 2-5 days' duration. In addition, the convenience of single-day treatment may lead to greater patient adherence and improved overall management of recurrent herpes outbreaks.
Collapse
Affiliation(s)
- Stephen Tyring
- Department of Dermatology, University of Texas Health Science Center, Houston, Texas 77058, USA.
| | | | | | | | | |
Collapse
|
38
|
Kmonícková E, Potmesil P, Holý A, Zídek Z. Purine P1 receptor-dependent immunostimulatory effects of antiviral acyclic analogues of adenine and 2,6-diaminopurine. Eur J Pharmacol 2005; 530:179-87. [PMID: 16371225 DOI: 10.1016/j.ejphar.2005.11.037] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2005] [Accepted: 11/14/2005] [Indexed: 11/17/2022]
Abstract
Acyclic nucleoside phosphonates are widely recognised antivirals. The oral prodrugs of prototype compounds, e.g., 9-[2-(phosphonomethoxy)ethyl]adenine (PMEA; adefovir), and 9-(R)-[2-(phosphonomethoxy)propyl]adenine [(R)-PMPA; tenofovir] were approved by FDA for treatment of hepatitis B (Hepsera), and acquired immunodeficiency syndrome (AIDS) (Viread), respectively. A number of acyclic nucleoside phosphonates possess immunostimulatory activity. The present experiments demonstrate that activation of cytokine and chemokine secretion is mediated by adenosine receptors. Included in the study were 9-(R)-[2-(phosphonomethoxy)propyl]adenine [tenofovir], N(6)-cyclopentyl-(R)-9-[2-(phosphonomethoxy)propyl]-2,6-diaminopurine, N(6)-cyclopropyl-(R)-9-[2-(phosphonomethoxy)propyl]-2,6-diaminopurine, and N(6)-isobutyl-9-[2-(phosphonomethoxy)ethyl]-2,6-diaminopurine. All of them activate secretion of tumor necrosis factor-alpha (TNF-alpha), interleukin-10 (IL-10), "regulated on activation of normal T cell expressed and secreted" (RANTES/CCL5), and macrophage inflammatory protein-1alpha (MIP-1alpha/CCL3) in murine macrophages. With exception of MIP-1alpha, the effects were inhibited by antagonists of adenosine A(1), A(2B), and A(3) receptors (not by adenosine A(2A) receptor antagonist). The adenosine A(1) receptor antagonist inhibited TNF-alpha, IL-10, and RANTES, adenosine A(2B) receptor antagonist inhibited TNF-alpha and RANTES, and adenosine A(3) receptor antagonist inhibited IL-10 and RANTES. The suppression is due to decreased transcription of cytokine mRNA. It may be suggested that acyclic nucleoside phosphonates are nonspecific ligands for purine P(1) receptors.
Collapse
Affiliation(s)
- Eva Kmonícková
- Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague.
| | | | | | | |
Collapse
|
39
|
Frémont M, Vaeyens F, Herst CV, De Meirleir KL, Englebienne P. Double-stranded RNA-dependent protein kinase (PKR) is a stress-responsive kinase that induces NFkappaB-mediated resistance against mercury cytotoxicity. Life Sci 2005; 78:1845-56. [PMID: 16324719 DOI: 10.1016/j.lfs.2005.08.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2005] [Accepted: 08/18/2005] [Indexed: 11/29/2022]
Abstract
The interferon-inducible, double-stranded (ds)RNA-dependent protein kinase (PKR) plays a major role in antiviral defense mechanisms where it down-regulates translation via phosphorylation of eukaryotic translation initiation factor 2alpha. PKR is also involved in the activation of nuclear factor kappaB (NFkappaB) through activation of the IkappaB kinase complex. Activation of PKR can occur in the absence of dsRNA and in such case is controlled by intracellular regulators like the PKR-activating protein (PACT), the PKR inhibitor p58(IPK), or heat-shock proteins (Hsp). These regulators are activated by stress stimuli, supporting a role for PKR in response to stress; however the final outcome of PKR activation in stress situations is unclear. We present here evidence that expression and activation of PKR contributes to an increased cellular resistance to mercury cytotoxicity. In two cell lines constitutively expressing PKR (THP-1 and Molt-3), treatment with the PKR inhibitor 2-aminopurine increases their sensitivity to mercury. In contrast, Ramos cells, which do not constitutively express PKR, present an increased resistance to mercury when PKR expression is induced by polyIC or interferon-beta treatment. This protective effect is inhibited by 2-aminopurine. We also show that exposure of Ramos cells to mercury leads to the induction of Hsp70. Treatment of cells with Hsp70 or NFkappaB inhibitors suppresses the PKR-dependent protection. We propose a model where PKR, modulated by Hsp70, activates a NFkappaB-mediated protective pathway. Because the cytotoxicity of mercury is primarily due to the generation of reactive oxygen species, our results suggest a more general function of PKR in the mechanisms of cellular response to oxidative stress.
Collapse
Affiliation(s)
- Marc Frémont
- R.E.D. Laboratories, Pontbeek 61, B-1731 Zellik, Belgium
| | | | | | | | | |
Collapse
|
40
|
Taylor VL, Titball RW, Oyston PCF. Oral immunization with a dam mutant of Yersinia pseudotuberculosis protects against plague. Microbiology (Reading) 2005; 151:1919-1926. [PMID: 15941999 DOI: 10.1099/mic.0.27959-0] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Inactivation of the gene encoding DNA adenine methylase (dam) has been shown to attenuate some pathogens such as Salmonella enterica serovar Typhimurium and is a lethal mutation in others such as Yersinia pseudotuberculosis strain YPIII. In this study the dam methylase gene in Yersinia pseudotuberculosis strain IP32953 was inactivated. Unlike the wild-type, DNA isolated from the mutant could be digested with MboI, which is consistent with an altered pattern of DNA methylation. The mutant was sensitive to bile salts but not to 2-aminopurine. The effect of dam inactivation on gene expression was examined using a DNA microarray. In BALB/c mice inoculated orally or intravenously with the dam mutant, the median lethal dose (MLD) was at least 10(6)-fold higher than the MLD of the wild-type. BALB/c mice inoculated with the mutant were protected against a subcutaneous challenge with 100 MLDs of Yersinia pestis strain GB and an intravenous challenge with 300 MLDs of Y. pseudotuberculosis IP32953.
Collapse
Affiliation(s)
- Victoria L Taylor
- Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire SP4 0JQ, UK
| | - Richard W Titball
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel St, London WC1E 7HT, UK
- Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire SP4 0JQ, UK
| | - Petra C F Oyston
- Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire SP4 0JQ, UK
| |
Collapse
|
41
|
Abstract
Toward the goal of developing effective treatments for prostate cancers, we examined the effects of cyclin-dependent kinase inhibitors on the survival of prostate cancer cells. We show that roscovitine, R-roscovitine, and CGP74514A (collectively referred to as CKIs) induce the apoptosis of LNCaP and LNCaP-Rf cells, both of which express wild-type p53. Apoptosis required caspase-9 and caspase-3 activity, and cytochrome c accumulated in the cytosol of CKI-treated cells. Amounts of p53 increased substantially in CKI-treated cells, whereas amounts of the endogenous caspase inhibitor XIAP decreased. CKIs did not appreciably induce the apoptosis of LNCaP cells treated with pifithrin-alpha, which prevents p53 accumulation, or of prostate cancer cells that lack p53 function (PC3 and DU145). Ectopic expression of p53 in PC3 cells for 44 hours did not reduce XIAP abundance or induce apoptosis. However, p53-expressing PC3 cells readily apoptosed when exposed to CKIs or when depleted of XIAP by RNA interference. These findings show that CKIs induce the mitochondria-mediated apoptosis of prostate cancer cells by a dual mechanism: p53 accumulation and XIAP depletion. They suggest that these events in combination may prove useful in the treatment of advanced prostate cancers.
Collapse
Affiliation(s)
- Subhra Mohapatra
- Department of Interdisciplinary Oncology, H. Lee Moffitt Cancer Center and Research Institute and University of South Florida Medical Center, Tampa, Florida 33612, USA.
| | | | | | | |
Collapse
|
42
|
Ouyang Y, Salstrom J, Diaz-Perez S, Nahas S, Matsuno Y, Dawson D, Teitell MA, Horvath S, Riggs AD, Gatti RA, Marahrens Y. Inhibition of Atm and/or Atr disrupts gene silencing on the inactive X chromosome. Biochem Biophys Res Commun 2005; 337:875-80. [PMID: 16213462 DOI: 10.1016/j.bbrc.2005.09.122] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2005] [Accepted: 09/16/2005] [Indexed: 01/02/2023]
Abstract
ATM and ATR are well documented for their roles in maintaining the integrity of genomic DNA by responding to DNA damage and preparing the cell for repair. Since ATM and ATR have been reported to exist in complexes with histone deacetylases, we asked whether Atm and Atr might also uphold gene silencing by heterochromatin. We show that the Atm/Atr inhibitor 2-aminopurine causes the inactive X chromosome to accumulate abnormal chromatin and undergo unwanted gene reactivation. We provide evidence that this gene expression from the inactive X chromosome is not a byproduct of the accumulation of DNA breaks. Individually inhibiting Atm and Atr by either small interfering RNA or the expression of dominant-negative ATM and ATR constructs also compromised X-inactivation. Atm and Atr, therefore, not only function in responding to DNA damage but perhaps also are involved in gene silencing via the maintenance of heterochromatin.
Collapse
Affiliation(s)
- Yan Ouyang
- Department of Human Genetics, The David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Chen Y, Hamati E, Lee PK, Lee WM, Wachi S, Schnurr D, Yagi S, Dolganov G, Boushey H, Avila P, Wu R. Rhinovirus induces airway epithelial gene expression through double-stranded RNA and IFN-dependent pathways. Am J Respir Cell Mol Biol 2005; 34:192-203. [PMID: 16210696 PMCID: PMC2644182 DOI: 10.1165/rcmb.2004-0417oc] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Rhinovirus (RV) infection is the major cause of common colds and of asthma exacerbations. Because the epithelial cell layer is the primary target of RV infection, we hypothesize that RV-induced airway disease is associated with the perturbation of airway epithelial gene expression. In this study, well differentiated primary human airway epithelial cells were infected with either RV16 (major group) or RV1B (minor group). Transcriptional gene profiles from RV-infected and mock-infected control cells were analyzed by Affymetrix Genechip, and changes of the gene expression were confirmed by real-time RT-PCR analysis. At 24 h after infection, 48 genes induced by both viruses were identified. Most of these genes are related to the IFN pathway, and have been documented to have antiviral functions. Indeed, a significant stimulation of IFN-beta secretion was detected after RV16 infection. Neutralizing antibody specific to IFN-beta and a specific inhibitor of the Janus kinase pathway both significantly blocked the induction of RV-inducible genes. Further studies demonstrated that 2-aminopurine, a specific inhibitor double-stranded RNA-dependent protein kinase, could block both IFN-beta production and RV-induced gene expression. Thus, IFN-beta-dependent pathway is a part of the double-stranded RNA-initiated pathway that is responsible for RV-induced gene expression. Consistent with its indispensable role in the induction of antiviral genes, deactivation of this signaling pathway significantly enhanced viral production. Because increase of viral yield is associated with the severity of RV-induced airway illness, the discovery of an epithelial antiviral signaling pathway in this study will contribute to our understanding of the pathogenesis of RV-induced colds and asthma exacerbations.
Collapse
Affiliation(s)
- Yin Chen
- Center for Comparative Respiratory Biology and Medicine, Genomic and Biomedical Sciences Facility, Suite 6510, University of California at Davis, One Shields Ave., Davis, CA 95616, USA.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Aleem E, Kiyokawa H, Kaldis P. Cdc2-cyclin E complexes regulate the G1/S phase transition. Nat Cell Biol 2005; 7:831-6. [PMID: 16007079 DOI: 10.1038/ncb1284] [Citation(s) in RCA: 298] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2005] [Accepted: 06/20/2005] [Indexed: 11/09/2022]
Abstract
The cyclin-dependent kinase inhibitor p27(Kip1) is known as a negative regulator of cell-cycle progression and as a tumour suppressor. Cdk2 is the main target of p27 (refs 2, 3) and therefore we hypothesized that loss of Cdk2 activity should modify the p27(-/-) mouse phenotype. Here, we show that although p27(-/-) Cdk2(-/-) mice developed ovary tumours and tumours in the anterior lobe of the pituitary, we failed to detect any functional complementation in p27(-/-) Cdk2(-/-) double-knockout mice, indicating a parallel pathway regulated by p27. We observed elevated levels of S phase and mitosis in tissues of p27(-/-) Cdk2(-/-) mice concomitantly with elevated Cdc2 activity in p27(-/-) Cdk2(-/-) extracts. p27 binds to Cdc2, cyclin B1, cyclin A2, or suc1 complexes in wild-type and Cdk2(-/-) extracts. In addition, cyclin E binds to and activates Cdc2. Our in vivo results provide strong evidence that Cdc2 may compensate the loss of Cdk2 function.
Collapse
Affiliation(s)
- Eiman Aleem
- Mouse Cancer Genetics Program, National Cancer Institute, NCI-Frederick, Bldg 560/22-56, 1050 Boyles Street, Frederick, MD 21702-1201, USA
| | | | | |
Collapse
|
45
|
Andrei G, Sienaert R, McGuigan C, De Clercq E, Balzarini J, Snoeck R. Susceptibilities of several clinical varicella-zoster virus (VZV) isolates and drug-resistant VZV strains to bicyclic furano pyrimidine nucleosides. Antimicrob Agents Chemother 2005; 49:1081-6. [PMID: 15728906 PMCID: PMC549231 DOI: 10.1128/aac.49.3.1081-1086.2005] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Varicella-zoster virus (VZV) is responsible for primary infections as well as reactivations after latency in the dorsal root ganglia. The treatment of such infections is mandatory for immunocompromised patients and highly recommended for elderly patients with herpes zoster infections (also called zona or shingles). The treatment of choice is presently based on four molecules, acyclovir (ACV), valaciclovir, famciclovir, and (in Europe) brivudine (BVDU). We present here our data on the antiviral activity of a new class of potent and selective anti-VZV compounds, bicylic pyrimidine nucleoside analogues (BCNAs), against a broad variety of clinical isolates and different drug-resistant virus strains. The results show that the BCNAs are far more potent inhibitors than ACV and BVDU against clinical VZV isolates as well as the VZV reference strains Oka and YS. The BCNAs were not active against ACV- and BVDU-resistant VZV strains bearing mutations in the viral thymidine kinase gene but kept their inhibitory potential against virus strains with mutations in the VZV DNA polymerase gene. Mutant virus strains selected in the presence of the BCNAs were solely cross-resistant to drugs, such as ACV and BVDU, that depend for their antiviral action on metabolic activation by the viral thymidine kinase.
Collapse
Affiliation(s)
- Graciela Andrei
- Rega Institute for Medical Research, Minderbroedersstraat 10, B-3000 Leuven, Belgium.
| | | | | | | | | | | |
Collapse
|
46
|
Gupta AK, Rusterholz C, Holzgreve W, Hahn S. Constant IFNgamma mRNA to protein ratios in cord and adult blood T cells suggests regulation of IFNgamma expression in cord blood T cells occurs at the transcriptional level. Clin Exp Immunol 2005; 140:282-8. [PMID: 15807852 PMCID: PMC1809372 DOI: 10.1111/j.1365-2249.2005.02758.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Low levels of IFNgamma produced by umbilical cord blood (UCB) T lymphocytes upon activation may be due to the need for a high threshold of activation or to intrinsic blocking transcription/translation. We examined IFNgamma mRNA accumulation and protein expression in pharmacologically stimulated human UCB and adult blood (AB) T cells. Our data indicate that both IFNgamma mRNA accumulation and protein synthesis were significantly lower in stimulated UCB T cells than the AB T cells. Since the RNA dependent kinase PKR, an inhibitor of translation, can be activated by low levels of IFNgamma mRNA, we measured its involvement. Treatment with 2-amino-purine, an inhibitor of PKR, did not enhance IFNgamma protein expression in UCB T cells. Furthermore, our studies indicated that IFNgamma promoter hypermethylation does not appear to regulate IFNgamma expression either, as treatment with the demethylating agent, 5-aza-2'-deoxycytidine, did not lead to a significant increase in IFNgamma mRNA accumulation in UCB T cells. What is readily evident from our studies is that the IFNgamma mRNA to protein ratio was similar in UCB and AB T cells and it was not altered by any of the treatments used. These results therefore suggests that IFNgamma expression in UCB T cells is suppressed at the transcriptional level by an unknown mechanism(s).
Collapse
Affiliation(s)
- A Kumar Gupta
- Laboratory for Prenatal Medicine, University Women's Hospital/Department of Research, University of Basel, Spitalstrasse, 21 CH 4031 Basel, Switzerland
| | | | | | | |
Collapse
|
47
|
Sugiyama T, Fujita M, Koide N, Mori I, Yoshida T, Mori H, Yokochi T. 2-aminopurine inhibits lipopolysaccharide-induced nitric oxide production by preventing IFN-beta production. Microbiol Immunol 2005; 48:957-63. [PMID: 15611612 DOI: 10.1111/j.1348-0421.2004.tb03625.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
2-aminopurine (2-AP) is widely used as a specific inhibitor for double stranded-RNA dependent protein kinase (PKR). Here we report that 2-AP can inhibit lipopolysaccharide (LPS)-stimulated nitric oxide (NO) production through the prevention of interferon (IFN)-beta production. 2-AP significantly inhibited NO production in LPS-stimulated RAW 264 murine macrophage cells. 2-AP also reduced the expression of IFN-beta and IFN-inducible genes, such as IFN-gamma-inducible protein (IP)-10 and immune-responsive gene (IRG)-1, and the inducible type of NO synthase (iNOS) mRNA in response to LPS. The addition of exogenous IFN-beta restored 2-AP-inhibited NO production in response to LPS. On the other hand, there was only partial inhibition by 2-AP of nuclear factor (NF)-kappaB activation, IL-6 mRNA expression and tumor necrosis factor (TNF)-alpha production. These results suggested that 2-AP inhibited LPS-induced IFN-beta production by preventing Toll/IL-1 receptor domain-containing adaptor-inducing IFN-beta (TRIF)-dependent signaling rather than myeloid differentiation factor (MyD) 88-dependent signaling, resulting in the inhibition of NO production.
Collapse
Affiliation(s)
- Tsuyoshi Sugiyama
- Department of Microbiology and Immunology, School of Medicine and Research Center for Infectious Disease, Aichi Medical University, Aichi 480-1195, Japan.
| | | | | | | | | | | | | |
Collapse
|
48
|
Hong ES, Yeung A, Funchain P, Slupska MM, Miller JH. Mutants with temperature-sensitive defects in the Escherichia coli mismatch repair system: sensitivity to mispairs generated in vivo. J Bacteriol 2005; 187:840-6. [PMID: 15659661 PMCID: PMC545721 DOI: 10.1128/jb.187.3.840-846.2005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
We have used direct selections to generate large numbers of mutants of Escherichia coli defective in the mismatch repair system and have screened these to identify mutants with temperature-sensitive defects. We detected and sequenced mutations that give rise to temperature-sensitive MutS, MutL, and MutH proteins. One mutation, mutS60, results in almost normal levels of spontaneous mutations at 37 degrees C but above this temperature gives rise to higher and higher levels of mutations, reaching the level of null mutations in mutS at 43 degrees C. However, at 37 degrees C the MutS60 protein can be much more easily titrated by mispairs than the wild-type MutS, as evidenced by the impaired ability to block homologous recombination in interspecies crosses and the increased levels of mutations from weak mutator alleles of mutD (dnaQ), mutC, and ndk. Strains with mutS60 can detect mispairs generated during replication that lead to mutation with much greater sensitivity than wild-type strains. The findings with ndk, lacking nucleotide diphosphate kinase, are striking. An ndk mutS60 strain yields four to five times the level of mutations seen in a full knockout of mutS. These results pose the question of whether similar altered Msh2 proteins result from presumed polymorphisms detected in tumor lines. The role of allele interactions in human disease susceptibility is discussed.
Collapse
Affiliation(s)
- Esther S Hong
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA
| | | | | | | | | |
Collapse
|
49
|
Tseng YD, Ge H, Wang X, Edwardson JM, Waring MJ, Fitzgerald WJ, Henderson RM. Atomic force microscopy study of the structural effects induced by echinomycin binding to DNA. J Mol Biol 2005; 345:745-58. [PMID: 15588823 DOI: 10.1016/j.jmb.2004.10.059] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2004] [Revised: 10/08/2004] [Accepted: 10/18/2004] [Indexed: 10/26/2022]
Abstract
Atomic force microscopy (AFM) has been used to examine the conformational effects of echinomycin, a DNA bis-intercalating antibiotic, on linear and circular DNA. Four different 398 bp DNA fragments were synthesized, comprising a combination of normal and/or modified bases including 2,6-diaminopurine and inosine (which are the corresponding analogues of adenine and guanosine in which the 2-amino group that is crucial for echinomycin binding has been added or removed, respectively). Analysis of AFM images provided contour lengths, which were used as a direct measure of bis-intercalation. About 66 echinomycin molecules are able to bind to each fragment, corresponding to a site size of six base-pairs. The presence of base-modified nucleotides affects DNA conformation, as determined by the helical rise per base-pair. At the same time, the values obtained for the dissociation constant correlate with the types of preferred binding site available among the different DNA fragments; echinomycin binds to TpD sites much more tightly than to CpG sites. The structural perturbations induced when echinomycin binds to closed circular duplex pBR322 DNA were also investigated and a method for quantification of the structural changes is presented. In the presence of increasing echinomycin concentration, the plasmid can be seen to proceed through a series of transitions in which its supercoiling decreases, relaxes, and then increases.
Collapse
Affiliation(s)
- Yolanda D Tseng
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK
| | | | | | | | | | | | | |
Collapse
|
50
|
Hornung V, Schlender J, Guenthner-Biller M, Rothenfusser S, Endres S, Conzelmann KK, Hartmann G. Replication-dependent potent IFN-alpha induction in human plasmacytoid dendritic cells by a single-stranded RNA virus. J Immunol 2004; 173:5935-43. [PMID: 15528327 DOI: 10.4049/jimmunol.173.10.5935] [Citation(s) in RCA: 158] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Plasmacytoid dendritic cells sense viral ssRNA or its degradation products via TLR7/8 and CpG motifs within viral DNA via TLR9. Although these two endosomal pathways operate independently of viral replication, little is known about the detection of actively replicating viruses in plasmacytoid dendritic cell (PDC). Replication and transcription of the viral genome of ssRNA viruses as well as many DNA viruses lead to the formation of cytosolic dsRNA absent in noninfected cells. In this study, we used human respiratory syncytial virus (HRSV) encoding a fusion (F) protein for direct cytosolic entry. Both HRSV infection and cytosolic delivery of a 65-nt dsRNA led to potent IFN-alpha induction in PDC, but not in myeloid dendritic cells. Inactivation of HRSV by UV irradiation abrogated IFN-alpha induction in PDC. The comparison of two respiratory syncytial virus (RSV) constructs carrying either the HRSV or the bovine RSV F protein revealed that F-mediated cytosolic entry of RSV was absolutely required for IFN-alpha induction in PDC. HRSV-induced IFN-alpha production was independent of endosomal acidification and of protein kinase R (PKR) kinase activity, as demonstrated with chloroquine and the PKR inhibitor 2-aminopurine, respectively. In contrast, the induction of IFN-alpha by the TLR7/8 ligand R848, by the TLR9 ligand CpG-A ODN 2216, and by inactivated influenza virus (TLR7/8 dependent) was completely blocked by 2-aminopurine. IFN-alpha induction by mouse pathogenic Sendai virus was not affected in PKR- and MyD88-deficient mice, confirming that a ssRNA virus, which is able to directly enter host cells via fusion at the plasma membrane, can be detected by PDC independently of PKR, TLR7/8, and TLR9.
Collapse
MESH Headings
- 2-Aminopurine/pharmacology
- Adaptor Proteins, Signal Transducing
- Animals
- Antigens, Differentiation/genetics
- Antigens, Differentiation/physiology
- B-Lymphocyte Subsets/immunology
- B-Lymphocyte Subsets/metabolism
- Cells, Cultured
- Dendritic Cells/enzymology
- Dendritic Cells/immunology
- Dendritic Cells/metabolism
- Dendritic Cells/virology
- Endosomes/immunology
- Endosomes/metabolism
- Humans
- Interferon-alpha/biosynthesis
- Interferon-alpha/radiation effects
- Membrane Glycoproteins/biosynthesis
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Monocytes/immunology
- Monocytes/metabolism
- Monocytes/virology
- Myeloid Cells/immunology
- Myeloid Cells/metabolism
- Myeloid Cells/virology
- Myeloid Differentiation Factor 88
- RNA, Double-Stranded/pharmacology
- Receptors, Cell Surface/biosynthesis
- Receptors, Immunologic/deficiency
- Receptors, Immunologic/genetics
- Receptors, Immunologic/physiology
- Respiratory Syncytial Virus, Human/immunology
- Respiratory Syncytial Virus, Human/physiology
- Respiratory Syncytial Virus, Human/radiation effects
- Sendai virus/immunology
- Toll-Like Receptor 7
- Toll-Like Receptor 9
- Toll-Like Receptors
- Ultraviolet Rays
- Viral Fusion Proteins/physiology
- Viral Proteins/physiology
- Virus Replication/immunology
- Virus Replication/radiation effects
- eIF-2 Kinase/antagonists & inhibitors
Collapse
Affiliation(s)
- Veit Hornung
- Department of Internal Medicine, Division of Clinical Pharmacology, Ludwig-Maximillians-University, Ziemssenstrasse 1, 80336 Munich, Germany
| | | | | | | | | | | | | |
Collapse
|