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
|
Szőke D, Kovács G, Kemecsei É, Bálint L, Szoták-Ajtay K, Aradi P, Styevkóné Dinnyés A, Mui BL, Tam YK, Madden TD, Karikó K, Kataru RP, Hope MJ, Weissman D, Mehrara BJ, Pardi N, Jakus Z. Nucleoside-modified VEGFC mRNA induces organ-specific lymphatic growth and reverses experimental lymphedema. Nat Commun 2021; 12:3460. [PMID: 34103491 PMCID: PMC8187400 DOI: 10.1038/s41467-021-23546-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [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: 01/13/2019] [Accepted: 04/30/2021] [Indexed: 12/01/2022] Open
Abstract
Lack or dysfunction of the lymphatics leads to secondary lymphedema formation that seriously reduces the function of the affected organs and results in degradation of quality of life. Currently, there is no definitive treatment option for lymphedema. Here, we utilized nucleoside-modified mRNA encapsulated in lipid nanoparticles (LNPs) encoding murine Vascular Endothelial Growth Factor C (VEGFC) to stimulate lymphatic growth and function and reduce experimental lymphedema in mouse models. We demonstrated that administration of a single low-dose of VEGFC mRNA-LNPs induced durable, organ-specific lymphatic growth and formation of a functional lymphatic network. Importantly, VEGFC mRNA-LNP treatment reversed experimental lymphedema by restoring lymphatic function without inducing any obvious adverse events. Collectively, we present a novel application of the nucleoside-modified mRNA-LNP platform, describe a model for identifying the organ-specific physiological and pathophysiological roles of the lymphatics, and propose an efficient and safe treatment option that may serve as a novel therapeutic tool to reduce lymphedema.
Collapse
Affiliation(s)
- Dániel Szőke
- Department of Physiology, Semmelweis University School of Medicine, Budapest, Hungary
- MTA-SE "Lendület" Lymphatic Physiology Research Group of the Hungarian Academy of Sciences and the Semmelweis University, Budapest, Hungary
| | - Gábor Kovács
- Department of Physiology, Semmelweis University School of Medicine, Budapest, Hungary
- MTA-SE "Lendület" Lymphatic Physiology Research Group of the Hungarian Academy of Sciences and the Semmelweis University, Budapest, Hungary
| | - Éva Kemecsei
- Department of Physiology, Semmelweis University School of Medicine, Budapest, Hungary
- MTA-SE "Lendület" Lymphatic Physiology Research Group of the Hungarian Academy of Sciences and the Semmelweis University, Budapest, Hungary
| | - László Bálint
- Department of Physiology, Semmelweis University School of Medicine, Budapest, Hungary
- MTA-SE "Lendület" Lymphatic Physiology Research Group of the Hungarian Academy of Sciences and the Semmelweis University, Budapest, Hungary
| | - Kitti Szoták-Ajtay
- Department of Physiology, Semmelweis University School of Medicine, Budapest, Hungary
- MTA-SE "Lendület" Lymphatic Physiology Research Group of the Hungarian Academy of Sciences and the Semmelweis University, Budapest, Hungary
| | - Petra Aradi
- Department of Physiology, Semmelweis University School of Medicine, Budapest, Hungary
- MTA-SE "Lendület" Lymphatic Physiology Research Group of the Hungarian Academy of Sciences and the Semmelweis University, Budapest, Hungary
| | - Andrea Styevkóné Dinnyés
- Department of Physiology, Semmelweis University School of Medicine, Budapest, Hungary
- MTA-SE "Lendület" Lymphatic Physiology Research Group of the Hungarian Academy of Sciences and the Semmelweis University, Budapest, Hungary
| | | | - Ying K Tam
- Acuitas Therapeutics, Vancouver, BC, Canada
| | | | | | - Raghu P Kataru
- Department of Surgery, Division of Plastic and Reconstructive Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | | | - Drew Weissman
- University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
| | - Babak J Mehrara
- Department of Surgery, Division of Plastic and Reconstructive Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Norbert Pardi
- University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA.
| | - Zoltán Jakus
- Department of Physiology, Semmelweis University School of Medicine, Budapest, Hungary.
- MTA-SE "Lendület" Lymphatic Physiology Research Group of the Hungarian Academy of Sciences and the Semmelweis University, Budapest, Hungary.
| |
Collapse
|
3
|
Oh SJ, Shin OS. SARS-CoV-2 Nucleocapsid Protein Targets RIG-I-Like Receptor Pathways to Inhibit the Induction of Interferon Response. Cells 2021; 10:530. [PMID: 33801464 PMCID: PMC7999926 DOI: 10.3390/cells10030530] [Citation(s) in RCA: 77] [Impact Index Per Article: 25.7] [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: 01/12/2021] [Revised: 02/23/2021] [Accepted: 02/24/2021] [Indexed: 12/14/2022] Open
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the coronavirus disease 2019 (COVID-19) that has resulted in the current pandemic. The lack of highly efficacious antiviral drugs that can manage this ongoing global emergency gives urgency to establishing a comprehensive understanding of the molecular pathogenesis of SARS-CoV-2. We characterized the role of the nucleocapsid protein (N) of SARS-CoV-2 in modulating antiviral immunity. Overexpression of SARS-CoV-2 N resulted in the attenuation of retinoic acid inducible gene-I (RIG-I)-like receptor-mediated interferon (IFN) production and IFN-induced gene expression. Similar to the SARS-CoV-1 N protein, SARS-CoV-2 N suppressed the interaction between tripartate motif protein 25 (TRIM25) and RIG-I. Furthermore, SARS-CoV-2 N inhibited polyinosinic: polycytidylic acid [poly(I:C)]-mediated IFN signaling at the level of Tank-binding kinase 1 (TBK1) and interfered with the association between TBK1 and interferon regulatory factor 3 (IRF3), subsequently preventing the nuclear translocation of IRF3. We further found that both type I and III IFN production induced by either the influenza virus lacking the nonstructural protein 1 or the Zika virus were suppressed by the SARS-CoV-2 N protein. Our findings provide insights into the molecular function of the SARS-CoV-2 N protein with respect to counteracting the host antiviral immune response.
Collapse
Affiliation(s)
| | - Ok Sarah Shin
- BK21 Graduate Program, Department of Biomedical Sciences, College of Medicine, Korea University Guro Hospital, Seoul
08308, Korea;
| |
Collapse
|
4
|
Chen YH, Zhao L, Jia XT, Li XY, Li CZ, Yan H, Weng SP, He JG. Isolation and characterization of cDNAs encoding Ars2 and Pasha homologues, two components of the RNA interference pathway in Litopenaeus vannamei. Fish Shellfish Immunol 2012; 32:373-380. [PMID: 22155278 DOI: 10.1016/j.fsi.2011.11.032] [Citation(s) in RCA: 11] [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] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 11/22/2011] [Accepted: 11/25/2011] [Indexed: 05/31/2023]
Abstract
The RNA interference (RNAi) is an evolutionarily conserved protective mechanism in eukaryotes against parasitic foreign nucleic acids. Previous studies demonstrated that the RNAi mechanism is important for shrimp antiviral immunity. Here, we report the identification and functional analysis of two key components of the shrimp RNAi activity: Litopenaeus vannamei arsenite resistance gene 2 (LvArs2) and partner of drosha (LvPasha). The full-length cDNA of LvArs2 was 3470 bp, including a 5' untranslated region (UTR) of 167 bp, a 3' UTR of 639 bp, and an open reading frame (ORF) of 2664 bp that encoded 887 amino acid residues with an estimated molecular mass of 102.5 kDa. The full-length cDNA of LvPasha was 2654 bp, including a 5' UTR of 99 bp, a 3' UTR of 560 bp, and an ORF of 1995 bp that encoded 664 amino acid residues with an estimated molecular mass of 74.2 kDa. Co-immunoprecipitation demonstrated that LvArs2 interacted with L. vannamei Dicer2 (LvDcr2) and LvPasha in Drosophila Schneider 2 (S2) cells, suggesting that LvArs2 may be involved in regulation of the miRNA/siRNA pathways in L.vannamei. Subcellular localization assays demonstrated both LvArs2 and LvPasha proteins mainly presented in the nucleus. After Poly(C-G) stimulation, the expression of LvArs2 was suppressed and expression of LvPasha was enhanced in shrimp gills. These results suggest that LvArs2 and LvPasha may participate in the defense against RNA viruses in crustacea.
Collapse
Affiliation(s)
- Yi-Hong Chen
- MOE Key Laboratory of Aquatic Product Safety/State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, 135 Xingang Road West, Guangzhou 510275, PR China
| | | | | | | | | | | | | | | |
Collapse
|
5
|
Mekata T, Sudhakaran R, Okugawa S, Inada M, Kono T, Sakai M, Itami T. A novel gene of tumor necrosis factor ligand superfamily from kuruma shrimp, Marsupenaeus japonicus. Fish Shellfish Immunol 2010; 28:571-578. [PMID: 20045063 DOI: 10.1016/j.fsi.2009.12.020] [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] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Revised: 12/15/2009] [Accepted: 12/15/2009] [Indexed: 05/28/2023]
Abstract
A tumor necrosis factor (TNF) gene has been isolated and characterized in kuruma shrimp, Marsupenaeus japonicus, providing the first conclusive evidence for the existence of the TNF ligand in shrimp. The kuruma shrimp TNF (MjTNF) cDNA was composed of 1868 bp with a 262 bp 5'-untranslated region (UTR) and a 220 bp 3'-UTR, which was translated into a protein of 462 amino acid residues that included a predicted transmembrane domain of 23 amino acid residues (Trp20-Val42) and the TNF family signature (Pro321-Leu448). Homology analysis of MjTNF showed 30.7% and 26.7% identities with fruit fly (Drosophila melanogaster) Eiger and human (Homo sapiens) ectodysplasin A, respectively. The MjTNF gene was constitutively expressed in unstimulated organs of shrimp such as the muscle, stomach, brain and gill. In lymphoid organ cells, an enhanced expression of the MjTNF gene was observed following stimulation with peptidoglycan and polycytidylic acid. A high expression level of MjTNF was observed in vivo 2 h and 4 h after stimulation with lipopolysaccharide and Vibrio penaeicida, respectively. These observations suggest that MjTNF plays a role in the innate immune defense in kuruma shrimp. The discovery of shrimp TNF will allow a more complete and concrete understanding of shrimp inflammatory responses.
Collapse
Affiliation(s)
- Tohru Mekata
- Interdisciplinary Graduate School of Agriculture and Engineering, University of Miyazaki, 1-1, Gakuen Kibanadai-nishi, 889-2192 Miyazaki, Japan
| | | | | | | | | | | | | |
Collapse
|
6
|
Abstract
Melanoma cells acquire multiple genetic and epigenetic alterations that promote their metastasis and resistance to available therapies. In this issue of Cancer Cell, Soengas and colleagues reveal that the induction of endosome-mediated autophagy results in efficient melanoma cell death, thereby offering new potential means for treatment of this devastating cancer.
Collapse
Affiliation(s)
- Hyungsoo Kim
- Signal Transduction Program, Burnham Institute for Medical Research, La Jolla, CA 92130, USA
| | | |
Collapse
|
7
|
Tormo D, Chęcińska A, Alonso-Curbelo D, Pérez-Guijarro E, Cañón E, Riveiro-Falkenbach E, Calvo TG, Larribere L, Megías D, Mulero F, Piris MA, Dash R, Barral PM, Rodríguez-Peralto JL, Ortiz-Romero P, Tüting T, Fisher PB, Soengas MS. Targeted activation of innate immunity for therapeutic induction of autophagy and apoptosis in melanoma cells. Cancer Cell 2009; 16:103-14. [PMID: 19647221 PMCID: PMC2851205 DOI: 10.1016/j.ccr.2009.07.004] [Citation(s) in RCA: 148] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2009] [Revised: 05/26/2009] [Accepted: 07/08/2009] [Indexed: 12/22/2022]
Abstract
Inappropriate drug delivery, secondary toxicities, and persistent chemo- and immunoresistance have traditionally compromised treatment response in melanoma. Using cellular systems and genetically engineered mouse models, we show that melanoma cells retain an innate ability to recognize cytosolic double-stranded RNA (dsRNA) and mount persistent stress response programs able to block tumor growth, even in highly immunosuppressed backgrounds. The dsRNA mimic polyinosine-polycytidylic acid, coadministered with polyethyleneimine as carrier, was identified as an unanticipated inducer of autophagy downstream of an exacerbated endosomal maturation program. A concurrent activity of the dsRNA helicase MDA-5 driving the proapoptotic protein NOXA resulted in an efficient autodigestion of melanoma cells. These results reveal tractable links for therapeutic intervention among dsRNA helicases, endo/lysosomes, and apoptotic factors.
Collapse
Affiliation(s)
- Damià Tormo
- Melanoma Laboratory, Molecular Pathology Programme, Spanish National Cancer Research Centre (CNIO), Madrid 28049, Spain
| | - Agnieszka Chęcińska
- Melanoma Laboratory, Molecular Pathology Programme, Spanish National Cancer Research Centre (CNIO), Madrid 28049, Spain
| | - Direna Alonso-Curbelo
- Melanoma Laboratory, Molecular Pathology Programme, Spanish National Cancer Research Centre (CNIO), Madrid 28049, Spain
| | - Eva Pérez-Guijarro
- Melanoma Laboratory, Molecular Pathology Programme, Spanish National Cancer Research Centre (CNIO), Madrid 28049, Spain
| | - Estela Cañón
- Melanoma Laboratory, Molecular Pathology Programme, Spanish National Cancer Research Centre (CNIO), Madrid 28049, Spain
| | - Erica Riveiro-Falkenbach
- Melanoma Laboratory, Molecular Pathology Programme, Spanish National Cancer Research Centre (CNIO), Madrid 28049, Spain
| | - Tonantzin G. Calvo
- Melanoma Laboratory, Molecular Pathology Programme, Spanish National Cancer Research Centre (CNIO), Madrid 28049, Spain
| | - Lionel Larribere
- Melanoma Laboratory, Molecular Pathology Programme, Spanish National Cancer Research Centre (CNIO), Madrid 28049, Spain
| | - Diego Megías
- Confocal Microscopy and Cytometry Unit, Spanish National Cancer Research Centre (CNIO), Madrid 28049, Spain
| | - Francisca Mulero
- Confocal Microscopy and Cytometry Unit, Spanish National Cancer Research Centre (CNIO), Madrid 28049, Spain
| | - Miguel A. Piris
- Lymphoma Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid 28049, Spain
| | - Rupesh Dash
- Department of Human and Molecular Genetics, VCU Institute of Molecular Medicine and VCU Massey Cancer Center, Virginia Commonwealth University, School of Medicine, Richmond, Virginia 23298-0033, USA
| | - Paola M. Barral
- Department of Human and Molecular Genetics, VCU Institute of Molecular Medicine and VCU Massey Cancer Center, Virginia Commonwealth University, School of Medicine, Richmond, Virginia 23298-0033, USA
| | | | | | - Thomas Tüting
- Laboratory of Experimental Dermatology Dermatology, Department of Dermatology, University of Bonn, 53105 Bonn, Germany
| | - Paul B. Fisher
- Department of Human and Molecular Genetics, VCU Institute of Molecular Medicine and VCU Massey Cancer Center, Virginia Commonwealth University, School of Medicine, Richmond, Virginia 23298-0033, USA
| | - María S. Soengas
- Melanoma Laboratory, Molecular Pathology Programme, Spanish National Cancer Research Centre (CNIO), Madrid 28049, Spain
- Requests for reprints: María S. Soengas, Centro Nacional de Investigaciones Oncológicas, CNIO, Melchor Fernández Almagro 3. Madrid 28049, Spain. Phone: 34-91-732 8000-Ext 3680. FAX: 34-91-224 6980.
| |
Collapse
|
8
|
DeWitte-Orr SJ, Leong JAC, Bols NC. Induction of antiviral genes, Mx and vig-1, by dsRNA and Chum salmon reovirus in rainbow trout monocyte/macrophage and fibroblast cell lines. Fish Shellfish Immunol 2007; 23:670-82. [PMID: 17368049 DOI: 10.1016/j.fsi.2007.01.017] [Citation(s) in RCA: 18] [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] [Subscribe] [Scholar Register] [Received: 08/29/2006] [Revised: 01/16/2007] [Accepted: 01/19/2007] [Indexed: 05/14/2023]
Abstract
The expression of potential antiviral genes, Mx1, Mx2, Mx3 and vig-1, was studied in two rainbow trout cell lines: monocyte/macrophage RTS11 and fibroblast-like RTG-2. Transcripts were monitored by RT-PCR; Mx protein by Western blotting. In unstimulated cultures Mx1 and vig-1 transcripts were seen occasionally in RTS11 but rarely in RTG-2. A low level of Mx protein was seen in unstimulated RTS11 but not in RTG-2. In both cell lines, Mx and vig-1 transcripts were induced by a dsRNA, poly inosinic: poly cytidylic acid (poly IC), and by Chum salmon reovirus (CSV). Medium conditioned by cells previously exposed to poly IC or CSV and assumed to contain interferon (IFN) induced the antiviral genes in RTS11. However, RTG-2 responded only to medium conditioned by RTG-2 exposed previously to CSV. In both cell lines, poly IC and CSV induced Mx transcripts in the presence of cycloheximide, suggesting a direct induction mechanism, independent of IFN, was also possible. For CSV, ribavirin blocked induction in RTS11 but not in RTG-2, suggesting viral RNA synthesis was required for induction only in RTS11. In both RTS11 and RTG-2 cultures, Mx protein showed enhanced accumulation by 24h after exposure to poly IC and CSV, but subsequently Mx protein levels declined back to control levels in RTS11 but not in RTG-2. These results suggest that Mx can be regulated differently in macrophages and fibroblasts.
Collapse
Affiliation(s)
- Stephanie J DeWitte-Orr
- Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada
| | | | | |
Collapse
|
9
|
Abstract
Innate immunity is critically important for tumor surveillance and regulating tumor metastasis. Fractalkine (FKN, CX3CL1), operating through the receptor CX3CR1, is an effective chemoattractant and adhesion receptor for NK cells and monocytes, important constituents of the innate immune response. Previous studies have shown that over-expression of CX3CL1 by tumor cells enhances antitumor responses. However, since most tumors do not express CX3CL1, it remains unclear if CX3CL1/CX3CR1 has a role in tumor immunity in the absence of ligand over-expression. To determine the role of CX3CL1 and CX3CR1 in regulating antitumor immune responses, we tested the response of wildtype and CX3CR1-deficient animals to unmanipulated B16 melanoma that does not express CX3CL1. We studied the distribution and trafficking of mononuclear cells (MNC) under homeostatic conditions and in the presence of B16 metastatic melanoma, cytotoxic activity, and cytokine production in wild-type and CX3CR1-deficient animals. We found that B16-treated CX3CR1-/- mice had increased lung tumor burden and cachexia. There was a selective reduction of monocytes and NK cells in the lungs of CX3CR1-deficient animals under homeostatic conditions and in response to B16. CX3CR1-deficient NK cells effectively killed B16 cells in cytotoxicity assays. However, CX3CR1-deficient NK cells exhibited a tumorigenic cytokine production profile with defective IFN-gamma expression and enhanced IL-6 production in response to TLR3 activation with polyIC. Our studies indicate that CX3CR1 is an important contributor to innate immunity at multiple levels. Its role in tumor immunity is not limited by expression of CX3CL1 by tumor cells.
Collapse
MESH Headings
- Animals
- CD3 Complex/analysis
- CX3C Chemokine Receptor 1
- Cell Line, Tumor
- Cytokines/analysis
- Cytokines/metabolism
- Cytotoxicity, Immunologic/drug effects
- Cytotoxicity, Immunologic/genetics
- Female
- Flow Cytometry
- Immunohistochemistry
- Interferon-gamma/metabolism
- Interleukin-6/metabolism
- Killer Cells, Natural/immunology
- Killer Cells, Natural/metabolism
- Lung/metabolism
- Lung/pathology
- Male
- Melanoma, Experimental/immunology
- Melanoma, Experimental/metabolism
- Melanoma, Experimental/pathology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Monocytes/metabolism
- Monocytes/pathology
- Poly C/pharmacology
- Receptors, Chemokine/deficiency
- Receptors, Chemokine/genetics
- Tumor Burden
Collapse
Affiliation(s)
- Yen-Rei A Yu
- Thurston Arthritis Research Center and the Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | | | | | | | | | | |
Collapse
|
10
|
Abstract
Recent toxicological studies indicate that nanoparticles or ultrafine particles (< 100 nm) are more toxic than fine particles (< 2 microm) because of their greater surface area. It is well known that alveolar macrophages play an important role in the first defense against various environmental particles and microorganisms. This is accomplished by binding to a macrophage receptor with collagenous structure (MARCO), one of several scavenger-type receptors expressed on the cell surface of macrophages. MARCO has been shown to mediate the ingestion of unopsonized environmental particles such as TiO(2) and Fe(2)O(3) (1.3 microm in diameter). However, very little is known about the cellular uptake of nanoparticles. In the present study, we investigated whether MARCO mediates the uptake of nanoparticles by using fluorescent-tagged polystyrene particles (20 nm, 200 nm, and 1 microm in diameter). COS-7 cells were transfected with either MARCO cDNA or an empty vector, and the association of the particles with the cells were observed by fluorescence microscopy and atomic force microscopy. MARCO-transfected cells associated with all three sizes of particles in a time-dependent manner, while no obvious binding of particles occurred after 5 h to the empty vector-transfected cells. The uptake of particles by MARCO-transfected cells was partially inhibited by polyG. These results suggest that macrophages associate with nanoparticles (20 nm) at least in part through MARCO and that MARCO plays a role in clearing nanoparticles which can deposit in the alveolar region.
Collapse
Affiliation(s)
- Sanae Kanno
- Environmental Nanotoxicology Section, Research Center for Environmental Risk, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, Japan.
| | | | | |
Collapse
|
11
|
Uchiyama Y, Tagami J, Kamisuki S, Kasai N, Oshige M, Chiku H, Ibe S, Koiwai O, Sugawara F, Sakaguchi K. Selective inhibitors of terminal deoxyribonucleotidyltransferase (TdT): baicalin and genistin. Biochim Biophys Acta Gen Subj 2005; 1725:298-304. [PMID: 16099107 DOI: 10.1016/j.bbagen.2005.06.017] [Citation(s) in RCA: 6] [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] [Received: 02/25/2005] [Revised: 06/29/2005] [Accepted: 06/29/2005] [Indexed: 10/25/2022]
Abstract
Studies of mammalian terminal deoxyribonucleotidyltransferase (TdT) are facilitated by use of inhibitors that selectively knock down the activity of the enzyme. We have screened for selective inhibitors of TdT and identified a natural compound with this property in the Japanese vegetable, Arctium lappa. The compound has little effect on the activities of mammalian DNA polymerases, such as alpha, beta, delta or lambda polymerase, and prokaryotic DNA polymerases, such as Taq DNA polymerase, T4 DNA polymerase and Klenow fragment. H1- and C13-NMR spectroscopic analyses showed the compound to be baicalin, a compound previously reported as an anti-inflammatory or antipyretic agent. The IC50 value of baicalin to TdT was 18.6 microM. We also found that genistin, a baicalin derivative known to be antimutagenic, more selectively inhibited TdT activity than baicalin, although its IC50 value was weaker (28.7 microM). Genistin and baicalin also inhibited the activity of truncated TdT (the so-called pol beta core domain) in which the BRCT motif was deleted in its N-terminal region. In kinetic analyses, inhibition by either genistin or baicalin was competitive with the primer and non-competitive with the dNTP substrate. The compounds may, therefore, bind directly to the primer-binding site of TdT and simultaneously disturb dNTP substrate incorporation into the primer. Genistin and baicalin should prove to be useful agents for studying TdT.
Collapse
Affiliation(s)
- Yukinobu Uchiyama
- Department of Applied Biological Science and Frontier Research Center for Genomic Drug Discovery, Tokyo University of Science, Noda, Chiba 278-8510, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Dong Z, Wei H, Sun R, Hu Z, Gao B, Tian Z. Involvement of natural killer cells in PolyI:C-induced liver injury. J Hepatol 2004; 41:966-73. [PMID: 15582130 DOI: 10.1016/j.jhep.2004.08.021] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2004] [Revised: 08/23/2004] [Accepted: 08/26/2004] [Indexed: 12/11/2022]
Abstract
BACKGROUND/AIMS The roles of T cells, natural killer T cells (NKT) and macrophages in autoimmune hepatitis have been well documented. However, the roles of natural killer (NK) cells in liver injury remain obscure. Here we examined the effect of Polyinosinic: polycytidylic acid (PolyI:C)-activated NK cells on liver injury. METHODS Mice were intraperitoneally injected with PolyI:C at a dose of 20mug/g body wt. The percentage and absolute number of NK cells in the liver were analyzed with flow cytometry. Serum alanine transaminase (ALT) and aspartate aminotransferase (AST) assay and H-E staining were used to evaluate the liver injury. RESULTS Following PolyI:C injection, NK cells accumulation and activation occurred in the liver. Meanwhile, slight elevation of ALT/AST in the serum, mild inflammation and focal necrosis in the liver were also observed. Depletion of NK cells markedly attenuated PolyI:C-induced liver injury. Neutralization of endogenous Interleukin-12 produced by Kupffer cells abrogated the accumulation of NK cells in the liver and subsequent liver injury. The liver injury was also alleviated by neutralization of vascular cell adhesive molecule-1. CONCLUSIONS These findings suggest that PolyI:C preferentially recruits and activates hepatic NK cells, which may be responsible for the mild hepatitis.
Collapse
Affiliation(s)
- Zhongjun Dong
- School of Life Sciences, University of Science and Technology of China, 443 Huangshan Road, Hefei, Anhui 230027, China
| | | | | | | | | | | |
Collapse
|
13
|
Mykhaĭlyk IV, Prokopova KV, Ostapchenko LI, Kucherenko MI. [Activity of dsRNA-dependent protein kinase in rat lymphoid cells under the effect of X-ray irradiation]. Ukr Biokhim Zh (1999) 2003; 75:49-53. [PMID: 14574737] [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: 04/27/2023]
Abstract
The activity of dsRNA-dependent protein kinase, which is the key enzyme of the interferon signal system, was studied in the rat spleen and thymus lymphocytes under the influence of X-ray irradiation at 0.5 and 1 Gy doses and interferon inducers administration. An increase of the enzyme activity was established in the presence of FGA, concanavaline A, poly(I).poly(C) in vitro. The effect is intensified under the irradiation by 0.5 Gy dose. The protein kinase activity in lymphocytes is amplified in proportion to poly(I).poly(C) concentration, that was most pronounced in the irradiated animals. The comparative analysis of the action of interferon inducers on the dsRNA-dependent protein kinase activity was carried out. Two biological systems were used: in vivo (when the preparations were injected to the experimental animals) and in vivo (under the preincubation of isolated lymphocytes with the inducers). It was shown that the combined action of radiation and interferon inducers causes the stimulation of dsRNA-dependent protein kinase activity.
Collapse
|
14
|
Expert-Bezançon A, Le Caer JP, Marie J. Heterogeneous nuclear ribonucleoprotein (hnRNP) K is a component of an intronic splicing enhancer complex that activates the splicing of the alternative exon 6A from chicken beta-tropomyosin pre-mRNA. J Biol Chem 2002; 277:16614-23. [PMID: 11867641 DOI: 10.1074/jbc.m201083200] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Splicing of the chicken beta-tropomyosin exon 6A is stimulated, both in vivo and in vitro, by an intronic pyrimidine-rich element (S4) located 37 nucleotides downstream of exon 6A. Several pyrimidine-rich sequences are able to substitute for the natural S4 enhancer with various stimulatory effects. We show that the different enhancer sequences recruit U1 small nuclear ribonucleoprotein (SnRNP) to the exon 6A 5' splice site, with an efficiency that correlates with the splicing activation. By using RNA affinity and two-dimensional gel electrophoresis, we characterized several proteins that bind to the different enhancer sequences. Heterogeneous nuclear ribonucleoprotein (hnRNP) K and hnRNP I (polypyrimidine track-binding protein, PTB) exhibit a higher level of interaction with the strong enhancer sequences (S4) than with the weakest enhancers. Functional analysis shows that hnRNP K is a component of the enhancer complex that promotes exon 6A splicing through the wild-type S4 sequence. The addition of recombinant hnRNP K to nuclear extracts preincubated with poly(rC) RNA competitor completely restores splicing efficiency to the original level. hnRNP I (PTB) was also found associated with the strong enhancer sequences. Its function in the splicing of exon 6A is discussed.
Collapse
|
15
|
Yamasaki Y, Sumimoto K, Nishikawa M, Yamashita F, Yamaoka K, Hashida M, Takakura Y. Pharmacokinetic analysis of in vivo disposition of succinylated proteins targeted to liver nonparenchymal cells via scavenger receptors: importance of molecular size and negative charge density for in vivo recognition by receptors. J Pharmacol Exp Ther 2002; 301:467-77. [PMID: 11961045 DOI: 10.1124/jpet.301.2.467] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [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: 11/22/2022] Open
Abstract
In vivo disposition characteristics of succinylated (Suc-) proteins were studied after intravenous injection in mice in relation to their molecular characteristics as negatively charged macromolecules. Recombinant superoxide dismutase (SOD; molecular mass, 32 kDa), bovine serum albumin (BSA; molecular mass, 67 kDa), and bovine IgG (molecular mass, 150 kDa) were used to produce succinylated derivatives with different degrees of modification. (111)In-labeled Suc-SODs were rapidly excreted into the urine with no significant hepatic uptake. In contrast, (111)In-Suc-BSA and Suc-IgG were significantly taken up by liver nonparenchymal cells via scavenger receptors (SRs) according to the degree of succinylation and the dose injected. Interestingly, highly succinylated BSAs exhibited significant accumulation in the kidney at higher doses when the hepatic uptake was saturated. Pharmacokinetic analysis demonstrated that the hepatic uptake of succinylated proteins depended on the molecular size and the estimated surface density of succinylated amino residues. Further analysis based on a physiological pharmacokinetic model, involving a saturable process with Michaelis-Menten kinetics, revealed that the surface density of negative charges was correlated with the affinity of larger succinylated proteins for the hepatic SRs. Thus, the present study has provided useful basic information for a therapeutic strategy and the molecular design of succinylated proteins for use as drug carriers and therapeutic agents per se for SR-mediated targeting in vivo.
Collapse
Affiliation(s)
- Yasuomi Yamasaki
- Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto, Japan
| | | | | | | | | | | | | |
Collapse
|
16
|
Abstract
The interferon induced, dsRNA-activated, protein kinase, PKR, is a key regulator of translational initiation, playing an important role in the regulation of cell proliferation, apoptosis and transformation. PKR levels correlate inversely with proliferative activity in several human tumor systems. This inverse relationship breaks down in human invasive ductal breast carcinomas which exhibit high levels of PKR (Haines et al., Tumor Biol. 17 (1996) 5-12). Consistent with the data from human tumors, the levels of PKR in several breast carcinoma cell lines, MCF7, T47D, BT20, MDAMB231 and MDAMB468, are paradoxically high compared to those found in the normal breast cell lines MCF10A and Hs578Bst. The activity of affinity- or immuno-purified PKR from MCF7, T47D, and BT20 cells appears to be severely attenuated, as judged by its ability to autophosphorylate, or phosphorylate eIF2 alpha. Furthermore, the activity of the kinase from breast carcinoma cells is refractory to stimulation by dsRNA or heparin. However, PKR from breast carcinoma cells remains functional with respect to its ability to bind dsRNA. The activity of PKR from MCF10A cells is reduced by prior incubation with extracts from MCF7 cells, suggesting that MCF7 extracts contain a transdominant inhibitor of PKR. Deregulation of PKR may therefore provide a mechanism for the development or maintenance of a transformed phenotype of human breast carcinomas, mimicking the effects of manipulation of PKR or eIF2 activity observed in experimental systems. Thus, breast carcinomas may provide the first indication of a role for PKR in the pathogenesis of a naturally occurring human cancer.
Collapse
Affiliation(s)
- O Savinova
- Center of Marine Biotechnology, University of Maryland Biotechnology Institute, Baltimore, USA
| | | | | |
Collapse
|
17
|
Riba I, Gaskell SJ, Cho H, Widger WR, Kohn H. Evidence for the location of bicyclomycin binding to the Escherichia coli transcription termination factor Rho. J Biol Chem 1998; 273:34033-41. [PMID: 9852059 DOI: 10.1074/jbc.273.51.34033] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The commercial antibiotic bicyclomycin (Bcm) has been shown to target the essential transcription termination factor Rho in Escherichia coli. Little is known about the Bcm binding domain in Rho. A recent structure-activity relationship study led us to evaluate the reductive amination probe, 5a-(3-formylanilino)dihydrobicyclomycin (FD-Bcm). Biochemical studies showed that FD-Bcm possessed inhibitory activities comparable to Bcm in Rho-dependent ATPase and transcription termination assays. Incubation of Rho with FD-Bcm, ATP, and poly(C) followed by NaBH4 reduction and dialysis led to an appreciable loss of ATPase activity. Inclusion of Bcm with FD-Bcm in the reductive amination reaction protected Rho, indicating that Bcm and FD-Bcm competed for the same binding site in Rho. Incubation of Rho with FD-Bcm and poly(C) followed by NaBH4 reduction provided a sample with residual ATPase activity (12%). Mass spectrometric analysis indicated the presence of two proteins in an approximate 1.2:1 ratio, whose masses corresponded to wild-type Rho (47,010 Da) and lysine-modified Rho (47,417 Da), respectively. Trypsin digestion of the Rho sample followed by high performance liquid chromatography separation and tandem mass spectrometry analysis identified the site of modification as Lys181 within the combined tryptic fragment, Gly-Leu-Ile-Val-Ala-Pro-Pro-Lys-Ala-Gly-Lys (residues 174-184). Similar analysis of a lesser modified sample (following incubation with inclusion of ATP) showed that addition had again occurred at Lys181. These findings provide the first structural information concerning the site of Bcm binding in Rho.
Collapse
Affiliation(s)
- I Riba
- Michael Barber Centre for Mass Spectrometry, UMIST, P. O. Box 88, Manchester M60 1QD, United Kingdom
| | | | | | | | | |
Collapse
|
18
|
Surzhik MA, Vilner LM, Katchurin AL, Timkovskii AL. Template-dependent biosynthesis of poly(G) x poly (C) and its antiviral activity in vitro and in vivo. Antiviral Res 1998; 38:131-40. [PMID: 9707375 DOI: 10.1016/s0166-3542(98)00018-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [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: 02/08/2023]
Abstract
Experimental conditions for poly(G) synthesis from GTP on a poly(C) template with the aid of Escherichia coli DNA-dependent RNA polymerase were investigated. The reaction product was purified without the use of RNase. On the basis of spectral data, gel permeation chromatography, affinity adsorption and electron microscopic visualization, the poly(G) x poly(C) product was assumed to possess a high degree of structural regularity. Its in vitro and in vivo antiviral activities were compared with those of traditional poly(G) x poly(C) and poly(I) x poly(C). Template-dependent poly(G) x poly(C) was similar in its in vitro activity to poly(I) x poly(C) or even surpassed it, whereas the 'traditional' poly(G) x poly(C) was only slightly active in vitro. However, 'traditional' poly(G) x poly(C) and poly(I) x poly(C) had similar activity in vivo, whereas template-dependent poly(G) x poly(C) was much less active in vivo. The role of intramolecular structural regularity in the in vitro and in vivo antiviral activity of polyribonucleotide duplexes is discussed.
Collapse
Affiliation(s)
- M A Surzhik
- Division of Molecular and Radiation Biophysics, Petersburg Nuclear Physics Institute, Russian Academy of Sciences, Gatchina, Leningrad District
| | | | | | | |
Collapse
|
19
|
Makino Y, Yamano K, Kanemaki M, Morikawa K, Kishimoto T, Shimbara N, Tanaka K, Tamura T. SUG1, a component of the 26 S proteasome, is an ATPase stimulated by specific RNAs. J Biol Chem 1997; 272:23201-5. [PMID: 9287326 DOI: 10.1074/jbc.272.37.23201] [Citation(s) in RCA: 21] [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] [Indexed: 02/05/2023] Open
Abstract
SUG1 is an integral component of the 26 S proteasome. Belonging to a novel putative ATPase family, it shares four conserved motifs characteristic of ATP-dependent DNA/RNA helicases. Recombinant rat SUG1 (rSUG1) produced in Escherichia coli was highly purified and characterized in terms of its biochemical properties. The rSUG1 exhibited a Mg2+-dependent ATPase activity. The Km for ATP and Vmax of rSUG1 were 35 microM and 7 pmol of ATP/min/microg of protein, respectively. Both ATPase activity to release [32P]monophosphate and [32P]ATP-labeling activity were coordinately affected by cold ATP severely, GTP and UTP moderately, and CTP little. Interestingly, the rSUG1 ATPase activity was stimulated by poly(U) and poly(C), but not by poly(A), poly(G), or by any forms of DNAs tested. A UV cross-linking assay also indicated poly(U)- and poly(C)-stimulated labeling of rSUG1 with [alpha-32P]ATP. Moreover, the ATPase activity was facilitated by cellular poly(A)+ RNA, but not by poly(A)- RNA. RNA transcribed in vitro from cDNA encoding a b-Zip protein could stimulate the ATPase activity. This is the first report to demonstrate a specific RNA requirement for ATPase with respect to the proteasomal ATPases. Our present work suggests that SUG1 can specifically interact with protein-coding RNA (mRNA) and play some roles in mRNA metabolism.
Collapse
Affiliation(s)
- Y Makino
- Department of Biology, Faculty of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba-263, Japan
| | | | | | | | | | | | | | | |
Collapse
|
20
|
Abstract
Cytokine-mediated activation of inducible nitric oxide synthase (iNOS) in monocytes or macrophages is species specific. In contrast to rat or mouse, human macrophages do not produce measurable levels of nitric oxide (NO) when induced by inflammatory mediators. Exposure to noncytokine mediators such as tumor cells or viruses, however, has recently been shown to activate human iNOS. NO production in response to these mediators is much lower than that seen for rat or mouse cells and often requires several days of stimulation. We have found that the synthetic, doublestranded polyribonucleotide polyinosinic-polycytidilic acid (Poly I:C), commonly used to mimic viral exposure, activated iNOS in human monocyte-derived macrophages (MDM). The production of NO, measured by nitrite accumulation, was detected after 24 h of stimulation with Poly I:C. The single-stranded polyribonucleotide Poly I, but not Poly C, also increased NO production. Nitrite production was enhanced when the MDM were primed (pretreated) with gamma or alpha interferon or other immune mediators such as IL-4 and was reduced by the iNOS inhibitor, N-methyl-L-arginine (L-NMMA). The use of Poly I:C to initiate NO production in human macrophages provides a useful tool to study the differences between the commonly used animal models and human cells and may provide insight into the pathophysiological significance of these differences.
Collapse
Affiliation(s)
- J C Snell
- Department of Physiology and Biophysics, Georgetown University Medical Center, Washington, DC 20007, USA
| | | | | | | |
Collapse
|
21
|
Walter R, Hadasová E, Scheuch E, Siegmund W. Effects of streptolysin O, polyriboinosinic-polyribocytidylic acid and combinations with cyclophosphamide on the hepatic arylamine N-acetyltransferase and cytochrome P450-dependent monooxygenases in rats. Pharmazie 1996; 51:498-500. [PMID: 8774842] [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: 02/02/2023]
Abstract
There is evidence that immunostimulation depresses the function of various cytochrome P450 (CYP)-dependent monooxygenases but activates the arylamine N-acetyltransferase (NAT). Therefore, the effects of the synthetic immunostimulator polyriboinosinic-polyribocytidylic acid (plC, 8 mg/kg i.p.), of sublytic doses of the streptococcal toxin streptolysin O (SLO, 50 HU/kg i.v. for 5 d) and of the immunosuppressor cyclophosphamide (CP, 100 mg/kg i.p.) on NAT and some monooxygenases were studied in rat liver. It was also evaluated whether CP might antagonize the effects of plC and SLO on drug metabolism. SLO, plC and CP reduced CYP content and the activities of some monooxygenases. NAT was significantly inhibited by CP (given 5 d before sacrifice) but not by plC, SLO or CP when given 2 d before sacrifice. CP lacked any effect on NAT if it was administered prior to SLO. However, it deteriorated synergistically the inhibition of the monooxygenases caused by SLO and plC.
Collapse
Affiliation(s)
- R Walter
- Department of Pharmacology, Ernst Moritz Arndt University, Greifswald, Germany
| | | | | | | |
Collapse
|
22
|
Abstract
The pac1+ gene of the fission yeast Schizosaccharomyces pombe is essential for viability and its overexpression induces sterility and suppresses mutations in the pat1+ and snm1+ genes. The pac1+ gene encodes a protein that is structurally similar to RNase III from Escherichia coli, but its normal function is unknown. We report here the purification and characterization of the Pac1 protein after overexpression in E. coli. The purified protein is a highly active, double-strand-specific endoribonuclease that converts long double-stranded RNAs into short oligonucleotides and also cleaves a small hairpin RNA substrate. The Pac1 RNase is inhibited by a variety of double- and single-stranded polynucleotides, but polycytidylic acid greatly enhances activity and also promotes cleavage specificity. The Pac1 RNase produces 5'-phosphate termini and requires Mg2+; Mn2+ supports activity but causes a loss of cleavage specificity. Optimal activity was obtained at pH 8.5, at low ionic strength, in the presence of a reducing agent. The enzyme is relatively insensitive to N-ethylmaleimide but is strongly inhibited by ethidium bromide and vanadyl ribonucleoside complexes. The properties of the Pac1 RNase support the hypothesis that it is a eukaryotic homolog of RNase III.
Collapse
Affiliation(s)
- G Rotondo
- Department of Microbiology, New York University School of Medicine, NY 10016, USA
| | | |
Collapse
|
23
|
Ribó M, delCardayré SB, Raines RT, de Llorens R, Cuchillo CM. Production of human pancreatic ribonuclease in Saccharomyces cerevisiae and Escherichia coli. Protein Expr Purif 1996; 7:253-61. [PMID: 8860650 DOI: 10.1006/prep.1996.0036] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [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: 02/02/2023]
Abstract
Human pancreatic ribonuclease (HP-RNase) has considerable promise as a therapeutic agent. Structure-function analyses of HP-RNase have been impeded by the difficulty of obtaining the enzyme from its host. Here, a gene encoding HP-RNase was designed, synthesized, and inserted into two expression vectors that then direct the production of HP-RNase in Saccharomyces cerevisiae (fused to either an unmodified or a modified a-factor pre-pro segment) or Escherichia coli (fused to the pelB signal sequence). HP-RNase produced in S. cerevisiae was secreted into the medium as an active enzyme, isolable at 0.1-0.2 mg/liter of culture. This isolate was heterogeneous due to extensive glycosylation and incomplete maturation of the pre-pro segment. HP-RNase produced in E. coli with the pET expression system was purified from the insoluble fraction of the cell lysate. Renaturation of the reduced and denatured protein produced active, homogeneous enzyme recoverable at 1 mg/liter of culture. The N terminus of the HP-RNase produced from the bacterial expression system was processed fully in vivo. The yeast system, combined with techniques that allow detection of picograms of ribonuclease activity, offers a sensitive probe for studies of post-translational modification and secretory targeting in eukaryotic cells. The bacterial system enables studies both to reveal new structure-function relationships in ribonucleases and to evaluate the use of HP-RNase as a cytotoxin that is tolerated by the human immune system.
Collapse
Affiliation(s)
- M Ribó
- Unitat de Bioquímica i Biologia Molecular, Departament de Biologia, Universitat de Girona, Girona, Spain
| | | | | | | | | |
Collapse
|
24
|
Fujiwara M, Baldeschwieler JD, Grubbs RH. Receptor-mediated endocytosis of poly(acrylic acid)-conjugated liposomes by macrophages. Biochim Biophys Acta 1996; 1278:59-67. [PMID: 8611608 DOI: 10.1016/0005-2736(95)00183-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The uptake characteristics of negatively-charged liposomes made by conjugation of poly(acrylic acid) (PAA) were studied with respect to cultured RAW macrophages. The PAA-conjugated liposomes were internalized and digested in an acidic compartment at a much faster rate than the unmodified phosphatidylcholine (PC) liposomes. After incubation for 18 h, an over 5-fold increase in the uptake of PC liposomes was obtained by PAA conjugation. Subsequently, part of the aqueous phase of the internalized liposomes was exocytosed. Recognition of PAA by the macrophages seems to be responsible for the enhanced uptake of PAA-conjugated liposomes. Cross-competition experiments showed that PAA-conjugated liposomes inhibited the uptake of acetylated-low density lipoprotein (acetyl-LDL) by the macrophages and vice versa. The uptake of PAA-conjugated liposomes was also inhibited by dextran sulfate and maleylated-bovine serum albumin (maleyl-BSA), which are also known to bind to scavenger receptors. Poly(C) and BSA, which are not ligands for the scavenger receptor, competed poorly with the uptake of PAA-conjugated liposomes. Enhanced uptake of PAA-conjugated liposomes by CHO cells with low scavenger receptor expression was not observed. Unexpectedly, LDL, which is not a ligand for scavenger receptor, also partially inhibited the uptake of PAA-conjugated liposomes. The interaction of PAA-conjugated liposomes with macrophages is complex, and the endocytosis of PAA-conjugated liposomes most likely involves multiple receptors and/or pathways. The data obtained suggest that the high affinity binding of PAA-conjugated liposomes to macrophages may be due to recognition of the negative charges of PAA by cell surface receptors, including the scavenger receptor.
Collapse
Affiliation(s)
- M Fujiwara
- Division of Chemistry and Chemical Engineering, California Institute of Technology (Caltech 127-72), Pasadena 91125, USA
| | | | | |
Collapse
|
25
|
Kouyanou S, Pilali M, Fragoulis EG. Ribosome-associated ribonucleases from six-day larvae of the insect Ceratitis capitata. Biochem Mol Biol Int 1995; 37:1217-27. [PMID: 8747552] [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: 02/01/2023]
Abstract
A 34 kDa, poly(U) and poly(C)-specific ribonuclease, is shown to be tightly bound on purified polysomes from six-day-old larvae of the insect Ceratitis capitata. High salt treatment (400 mM KCl) is necessary to release it completely from the polysomes. Removal of the RNase does not disrupt the structure of the ribosomes, as shown by centrifugation on sucrose gradients and poly U directed polyphenylalanine synthesis.
Collapse
Affiliation(s)
- S Kouyanou
- Department of Biochemistry, Cell and Molecular Biology and Genetics, University of Athens, Greece
| | | | | |
Collapse
|
26
|
Nehashi K, Yoshida J, Wakabayashi T, Nagata M, Utsumi J, Naruse N, Sugita K. Growth inhibition of human glioma cells by superinduced human interferon-beta. Neurol Med Chir (Tokyo) 1995; 35:719-22. [PMID: 8532125 DOI: 10.2176/nmc.35.719] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Superinduction of human interferon-beta (HuIFN-beta) from human glioma cells has greater cytotoxicity than purified HuIFN-beta derived from fibroblasts. However, superinduction requires several reagents like polyI:polyC, cycloheximide, and actinomycin D, which may contaminate the conditioned medium and obscure the effect of superinduced HuIFN-beta. The present study used minimum doses of polyI:polyC and cycloheximide without actinomycin D to superinduce HuIFN-beta. The superinduced HuIFN-beta was purified by passing the medium through molecular sieve column chromatography. Fractionation of the eluate provided semipurified superinduced HuIFN-beta which demonstrated a growth inhibitory effect against both the U251-MG autologous human glioma cell line and the SK-MG-1 homologous glioma cell line. This effect was neutralized by addition of anti-HuIFN-beta monoclonal antibody (YSB-1). In a separate experiment, combinations of superinduction reagents were found not to have growth inhibitory effects because all inhibition in superinduced medium was completely neutralized by YSB-1. Superinduced HuIFN-beta has a pure growth inhibitory effect on both autologous and homologous glioma cells, so may affect autocrine secretion of cytokines.
Collapse
Affiliation(s)
- K Nehashi
- Department of Neurosurgery, Nagoya University School of Medicine, Japan
| | | | | | | | | | | | | |
Collapse
|
27
|
Aksenov OA, Murina EA, Kogan EM, Platonova GA, Sidorova NS, Timkovskiĭ AL. [Biological activity of the poly(G).poly(C) complex, modified by divalent platinum compounds]. Vopr Virusol 1995; 40:56-9. [PMID: 7762230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Modification of poly(G).poly(C) with cys-diaminodichloroplatinum (cys-DDP) at the level of rb = 0.02 increased the in vivo antiviral and interferon-inducing activity of the complex, in contrast to the data reported for complex poly(G).poly(C). Antiinfluenza activity in this case depends on the method of modification and increases more intensively when a ready complex is treated with cys-DDP, as against treatment of poly(G) alone before the formation of a complex with poly(C). If rb is increased, the activity reduces again. Modification with trans-DDP at rb = 0.02 also leads to an increase of antiinfluenza activity of poly(G).poly(C), but mainly after pretreatment of poly(G).
Collapse
|
28
|
Mordechai E, Kon N, Henderson EE, Suhadolnik RJ. Activation of the interferon-inducible enzymes, 2',5'-oligoadenylate synthetase and PKR by human T-cell leukemia virus type I Rex-response element. Virology 1995; 206:913-22. [PMID: 7856104 DOI: 10.1006/viro.1995.1014] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [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: 01/27/2023]
Abstract
In vitro-synthesized human T-cell leukemia virus type 1 (HTLV-I) Rex response element (Rex-RE) activates the interferon-induced 2',5'-oligoadenylate synthetase (2-50AS) in a dose-dependent manner. In addition, Rex-RE at 1 microgram/ml activates a second interferon-induced enzyme, p68 kinase (PKR); however, at 50 micrograms/ml, Rex-RE inhibits PKR activity. Poly(rl)-poly(rC) (10 micrograms/ml) dissociates the ribonucleoprotein complexes, Rex-RE/2-5OAS, or Rex-RE/PKR, whereas poly(rC) (100 micrograms/ml) does not, indicating the presence of high affinity interactions between Rex-RE and these two enzymes. To further characterize the interaction of Rex-RE with 2-5OAS and PKR, [32P]Rex-RE was uv-cross-linked to 2-5OAS and PKR present in interferon-treated HeLa cell extracts. The affinity of Rex-RE to highly purified 40-kDa human recombinant 2-5OAS was determined to be Kd = 4.7 nM. The relevance of these results to the pathogenesis of HTLV-I-associated adult T-cell leukemia/lymphoma is discussed.
Collapse
Affiliation(s)
- E Mordechai
- Department of Biochemistry, Temple University School of Medicine, Philadelphia, Pennsylvania 19140
| | | | | | | |
Collapse
|
29
|
Wang Y, von Hippel PH. Escherichia coli transcription termination factor rho. I. ATPase activation by oligonucleotide cofactors. J Biol Chem 1993; 268:13940-6. [PMID: 8314760] [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] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Rho protein is required to bring about RNA release from Escherichia coli transcription complexes paused at specific (rho-dependent) termination sites. Rho functions in termination as a hexamer of identical subunits arranged in D3 symmetry, with each rho subunit carrying an RNA- and an ATP-binding site. The detailed mechanism of rho-catalyzed transcript release remains to be determined, but it is clear that the RNA-dependent ATPase activity that is stimulated by interaction with the nascent transcript is essential to the termination function of rho. In this study, we have used short (8-10 nucleotide residues) synthetic ribo-oligonucleotides to model the interaction of segments of the RNA cofactor with rho. A poly(dC) enhancement procedure was used to permit the measurement of steady state ATPase parameters. We show that (i) ATPase activation is cofactor composition- and sequence-dependent; (ii) at least 60% of the residues of these short RNA cofactors must be cytosine to produce maximal rho ATPase activation; (iii) oligo(rU,rC) cofactors with the rU residues located at the 5' termini of the oligomer are much better ATPase cofactors than oligomers containing rC residues only; (iv) this enhanced stimulation is not observed if the rU residues are replaced by rA residues; (v) this cofactor activity relative to oligo(rC) is reversed if the rU residues are placed at the 3' terminus of RNA oligomer; and (vi) these nucleotide sequence and composition effects do not appear to be functions of K+ or Mg2+ concentration. These ATPase activation results are correlated with the binding to rho of oligonucleotide cofactors in the accompanying paper (Wang, Y., and von Hippel, P. H. (1993) J. Biol. Chem. 268, 13947-13955).
Collapse
Affiliation(s)
- Y Wang
- Institute of Molecular Biology, University of Oregon, Eugene 97403
| | | |
Collapse
|
30
|
Abstract
Bicyclomycin is a novel, commercially important antibiotic. Information concerning the site of bicyclomycin inhibition in Escherichia coli has been obtained by the production of bicyclomycin resistant mutants by UV irradiation. Selection by growth in the presence of bicyclomycin of a plasmid clone library generated from a highly resistant mutant in recipient antibiotic-sensitive host cells (E. coli strain W3350) has led to the characterization of three different plasmids that confer drug resistance, which contained the gene encoding the transcription termination factor, rho. These mutant rho genes contained single base changes at nucleotide positions 656, 796, and 1009. Preliminary mechanistic information has been obtained by monitoring the polyC-dependent ATPase activity of rho in the absence and presence of bicyclomycin and dihydrobicyclomycin. Addition of bicyclomycin to aqueous solutions containing rho and ATP led to a decrease in the release of inorganic phosphate with an I50 value of 60-70 microM bicyclomycin. This inhibition is comparable to the drug concentration needed to inhibit bacterial growth on plates. No loss of activity was observed when a similar concentration of dihydrobicyclomycin was used in place of bicyclomycin, while use of 10-fold higher concentrations of this derivative led to partial rho inhibition. PolyC-dependent ATPase activity from partially purified rho isolated from the mutant BCMr108 was not inhibited by bicyclomycin at concentrations (200 microM) found to completely inhibit wild-type rho. These cumulative findings are consistent with the notion that bicyclomycin expresses its activity by interfering with the polyC-dependent ATPase activity of rho.
Collapse
Affiliation(s)
- A Zwiefka
- Department of Chemistry, University of Houston, Texas 77204
| | | | | |
Collapse
|
31
|
Kuwahara SK, Mannering GJ. Effects of interferon, polyriboinosinic acid--polyribocytidilic acid and steroids on the cytochrome P450 system of cultured primary mouse hepatocytes. Pharmacol Toxicol 1993; 72:199-204. [PMID: 7690477 DOI: 10.1111/j.1600-0773.1993.tb01636.x] [Citation(s) in RCA: 4] [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: 01/26/2023]
Abstract
An earlier study from this laboratory showed that the hepatic murine cytochrome P450 (P450) system was depressed by interferon in vivo but induced in cultured primary hepatocytes. The current investigation attempted to resolve this contradiction. The P450 content of the cells used in the earlier study fell precipitously during the first 24 hr of culture and remained at the same low level throughout another 48 hr of incubation. This failure to maintain the P450 level suggested that the cells may not have been sufficiently viable to support the mechanisms involved in the depressant activity of interferon. Accordingly, a chemically defined medium containing hydrocortisone was devised which supported an acceptable level and function of the P450 system throughout a 72 hr incubation period. Functionality of the P450 system was evaluated by measuring aminopyrine N-demethylase and benzo[a]pyrene hydroxylase activities. When this steroid supplemented medium was used, interferon depressed both activities by about 25%; however, neither activity was affected significantly by poly IC. On the other hand, benzo[a]pyrene hydroxylase activity was depressed by both poly IC and interferon in hepatocytes induced with dexamethasone or with dexamethasone plus 3-methylcholanthrene. These studies emphasize the necessity of maintaining an acceptable level of homeostasis in cultured hepatocytes if one is to derive meaningful interpretations of certain biological events.
Collapse
Affiliation(s)
- S K Kuwahara
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis 55455
| | | |
Collapse
|
32
|
Messina JP, Gilkeson GS, Pisetsky DS. The influence of DNA structure on the in vitro stimulation of murine lymphocytes by natural and synthetic polynucleotide antigens. Cell Immunol 1993; 147:148-57. [PMID: 8462107 DOI: 10.1006/cimm.1993.1055] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.6] [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] [Indexed: 01/30/2023]
Abstract
Although DNA is generally considered to be a poor immunogen, recent evidence suggests that DNA from various species differ in their immunological activity and that bacterial DNA can induce the in vitro proliferation of normal murine B cells. To delineate structural features of DNA associated with mitogenic activity, the response of murine lymphocytes to various natural and synthetic polynucleotides was determined. Both ss and dsDNA from two different bacterial strains were equally effective in inducing proliferation. This response was independent of adenosine methylation, since DNA from dam- Escherichia coli stimulated proliferation. Among the synthetic polymers tested, only the duplexes poly(dG).poly(dC), and poly(dG.dC) were mitogenic, while polymers containing dA, dT, or dI alone or in combination with dG and dC were inactive. The mitogenic activity of poly(dG.dC) was eliminated, however, upon substitution of rG for dG or 5medC for dC. The mitogenic activity did not require high molecular weight DNA since active polymers ranged in size from approximately 260 to 800 base pairs. In addition, E. coli DNA fragments of 50-300 and 125-600 bases were mitogenic. Together, these data suggest that the mitogenic activity of DNA is dependent on sequence-specific determinants that can be presented by synthetic DNA duplexes as well as bacterial ss and dsDNA.
Collapse
Affiliation(s)
- J P Messina
- Medical Research Service, Durham Veterans Administration Hospital, North Carolina 27710
| | | | | |
Collapse
|
33
|
Abstract
Lethally irradiated genetically resistant (C57 x AKR) mice, unlike non-resistant (C3H x AKR) mice, which display genetic resistance to transplantation of parental C57 bone marrow grafts (GR to BMT), also reject transplanted parental AKR lymphoma grafts (GR to lymphoma). Depletion of natural killer (NK) cell activity of resistant (C57 x AKR) mice by anti-asialo GM-1 serum abrogated the resistance, whereas stimulation of NK cell activity of non-resistant (C3H x AKR) mice by polyinosinic: polycytidillic acid (poly I:C) induced the resistance to parental AKR lymphoma grafts. This shows that NK cells contribute to GR of (C57 x AKR) hybrid mice to parental AKR lymphoma grafts. Further, these results indicate that NK cells which confer genetic resistance to bone marrow transplantation (GR to BMT) in lethally irradiated (C57 x AKR) hybrid mice, also mediate GR to lymphoma transplantation in these mice, thereby linking GR to BMT with GR to lymphoma-leukemia.
Collapse
Affiliation(s)
- S K Datta
- Department of Surgery, Baylor College of Medicine, Houston, Texas 77030
| | | |
Collapse
|
34
|
Abstract
Transcription-termination factor rho of Escherichia coli functions as an RNA-dependent ATPase that causes transcript release at specific rho-dependent termination sites on the DNA template. Rho exists as a hexagon of identical subunits, physically organized as a trimer of dimers with D3 symmetry. The structural asymmetry of the dimer is reflected in the binding properties of rho; each dimer has a strong and a weak binding site for both the ATP substrate and the RNA cofactor. Here we use homopolynucleotides in competition and complementation experiments to characterize the ATPase activation properties of the cofactor binding sites of the functional rho dimer. We show that (i) no ATPase activity is observed unless both the high- and the low-affinity cofactor binding sites of the functional rho dimer are occupied; (ii) saturating levels of poly(rC), poly(rC) in combination with poly(rU), or poly(rU) alone can fully activate the ATPase of rho; and (iii) poly(dC) can serve as a fully competitive inhibitor of half of the ATPase activity of rho when one of the cofactor sites is filled with poly(rC). These observations lead to a set of phenomenological rules that describe the cofactor dependence of the ATPase activation of the functional dimer of rho and help to define a mechanistic basis for interpreting rho function in termination.
Collapse
Affiliation(s)
- S E Seifried
- Institute of Molecular Biology, University of Oregon, Eugene 97403
| | | | | |
Collapse
|
35
|
Geng BQ, Ho YK, Hughes RG, Bardos TJ. Inhibition of human cancer cell lines in vitro with mono- and polynucleotides containing 5-mercaptocytosine bases. Zhongguo Yao Li Xue Bao 1991; 12:115-20. [PMID: 1776473] [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] [Grants] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Partially thiolated polycytidylic acid (5-mercaptopolycytidylic, MPC) and its double-stranded complex with polyinosinic acid [poly (I)].poly(I).MPC, were assayed in both antiproliferative and cytotoxicity tests against human cell lines: lung carcinoma A549, colon carcinoma HT-29, osteosarcoma HOS, and amnion cells (WISH). Inhibitory effects of MPC were noted in the antiproliferative assay with ID50 of 7, 24, 33, and 35 micrograms.ml-1, and in the cytotoxicity test with ID50 of 164, 174, 210, and 290 micrograms.ml-1 against the HOS, A549, HT-29, and WISH cells respectively. Comparison with the corresponding partially thiolated mononucleotide (5-mercapto-CMP + CMP) and the nucleoside (5-mercapto-cytidine) demonstrated that MPC was a more potent antiproliferative agent than either of its monomeric constituents. The inhibitory effect of MPC upon the incorporation of [3H]thymidine into the DNA of growing A549 cells paralleled its antiproliferative activity.
Collapse
Affiliation(s)
- B Q Geng
- Department of Medicinal Chemistry, State University of New York, Buffalo 14260
| | | | | | | |
Collapse
|
36
|
Evstropov AN, Gritsenko LN, Khudonogova ZP, Iavorovskaia VE. [Effect of non-steroidal anti-inflammatory agents on interferon induction]. Antibiot Khimioter 1990; 35:27-8. [PMID: 1704699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Nonsteroid antiinflammatory agents (NAIA) such as antipyrine, butadion, acetylsalicylic acid, sodium salicylate, stampyrine and 4-iodantipyrine are not interferonogenic. Still, they stimulated interferonogenic action of poly(G).poly(C) in studies on animals. Relation between the interferon-stimulating action of the NAIA and their effect on activity of prostaglandin and the influence on the immune system was suggested.
Collapse
|
37
|
Dolan JW, Marshall NF, Richardson JP. Transcription termination factor rho has three distinct structural domains. J Biol Chem 1990; 265:5747-54. [PMID: 2318834] [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] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The domain structure of transcription termination factor rho was analyzed by partial trypsin cleavage and by photoaffinity labeling with ATP and oligo(C)5. A rho subunit consists of three distinct domains of nearly equal size that are connected by trypsin-sensitive linker segments. The amino-terminal domain binds to oligo(C)5 and has sequence segments with extended similarity to conserved elements in other RNA-binding proteins and a segment that has identities with another known cytidine nucleotide-binding protein. The middle domain has the ATP-binding site and has most of the sequence segments with similarity to conserved elements in other nucleoside triphosphate-binding proteins. The function of the third domain, the carboxyl-terminal domain, has not been identified. Both the amino- and carboxyl-terminal domains are relatively resistant to further trypsin treatment. The ATP-binding domain is also relatively resistant when it is linked to the amino-terminal, RNA-binding domain, but has not been detected as a separate digestion product. This result plus the finding that ADP and ATP inhibit the cleavage in the linker between the two domains indicate that those domains interact intimately in spite of their functional distinctions.
Collapse
Affiliation(s)
- J W Dolan
- Department of Chemistry, Indiana University, Bloomington 47405
| | | | | |
Collapse
|
38
|
Abstract
The role of ametantrone (HAQ) and mitoxantrone (DHAQ) in modulating the antiviral and interferon-inducing activities of poly r(A-U) was examined using the human foreskin fibroblast-vesicular stomatitis virus (HSF-VSV) bioassay system in which the concentration of poly r(A-U) was fixed at 0.05 mM or 0.2 mM while the HAQ or DHAQ concentration was varied to produce variable HAQ (or DHAQ)/ribonucleotide ratios ranging from 1:16 to 2:1. HAQ, DHAQ and poly r(A-U) tested individually were not efficacious antiviral agents. When poly r(A-U) was combined with the ametantrone or mitoxantrone the antiviral activity was potentiated 10-fold at HAQ (or DHAQ)/ribonucleotide ratios in the region of 1/4 to 1/6. The interferon-inducing activity of the HAQ (or DHAQ)/poly r(A-U) combinations were equal to the sum of the interferon-inducing activity of the poly r(A-U) and the HAQ (or DHAQ). These results indicate that the HAQ and DHAQ potentiate the antiviral activity of the poly r(A-U) without the superinduction of interferon. The direct viral inactivation study demonstrated that HAQ, DHAQ, poly r(A-U) and the HAQ (or DHAQ)/poly r(A-U) combinations did not inactivate the VSV at concentrations near the viral 50% inhibitory dose.
Collapse
Affiliation(s)
- J M Jamison
- Department of Chemistry, Kent State University, Ohio 44242
| | | | | | | |
Collapse
|
39
|
Dombroski AJ, LaDine JR, Cross RL, Platt T. The ATP binding site on rho protein. Affinity labeling of Lys181 by pyridoxal 5'-diphospho-5'-adenosine. J Biol Chem 1988; 263:18810-5. [PMID: 3143717] [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] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
We have labeled the nucleoside triphosphate-binding domain of Escherichia coli rho factor with the ATP affinity analog [3H]pyridoxal 5'-diphospho-5'-adenosine (PLP-AMP). PLP-AMP completely inactivates the RNA-dependent ATPase activity of rho upon incorporation of 3 mol of reagent/mol of hexameric rho protein. Although the potency of PLP-AMP is enhanced when an RNA substrate such as poly(C) is present, the stoichiometry for inhibition remains the same as in the absence of poly(C). The nucleotide substrate ATP competes very effectively for the binding site and protects against PLP-AMP inactivation. A domain of rho called N2, which comprises the distal two-thirds of the molecule (residues 152-419) and encompasses the region proposed to bind ATP, is labeled specifically in the presence of poly(C). Amino acid sequence analysis of the single [3H]PLP-AMP labeled proteolytic fragment showed Lys181 to be the site of modification, suggesting that this residue normally interacts with the gamma-phosphoryl of bound ATP. These results agree with our proposed tertiary structure for the ATP-binding domain of rho that places this lysine residue in a flexible loop above a hydrophobic nucleotide-binding pocket comprised of several parallel beta-strands, similar to adenylate kinase, F1-ATPase, and related ATP-binding proteins. Parallel studies of rho structure and function by site-directed mutagenesis and chemical modification support this interpretation.
Collapse
Affiliation(s)
- A J Dombroski
- Department of Biochemistry, University of Rochester Medical Center, New York 14642
| | | | | | | |
Collapse
|
40
|
Majumdar C, Abbotts J, Broder S, Wilson SH. Studies on the mechanism of human immunodeficiency virus reverse transcriptase. Steady-state kinetics, processivity, and polynucleotide inhibition. J Biol Chem 1988; 263:15657-65. [PMID: 2459125] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
A study of steady-state kinetics of polymerization by purified human immunodeficiency virus DNA polymerase (reverse transcriptase) has been conducted. DNA synthesis was examined using a system of poly(rA) as template, oligo(dT) as primer, and dTTP as nucleotide substrate. The substrate initial velocity patterns point to an ordered mechanism with template-primer adding first. Product inhibition kinetics with either pyrophosphate or phosphonoformate are consistent with this mechanism. The human immunodeficiency virus reverse transcriptase acts processively in this replication system, but exhibits some probability of terminating after each dTMP addition to the nascent chain. The probability of terminating was approximately 20-fold higher after the first dTMP addition than after subsequent additions. With this information on the mode of polymerization, appropriate kinetic models and steady-state rate equations are discussed. In further studies, we found that a heterologous polynucleotide, poly(rC), is a potent inhibitor of the enzyme. The pattern of this inhibition is uncompetitive against template-primer, suggesting that interaction with free enzyme is not the mechanism of the inhibition.
Collapse
Affiliation(s)
- C Majumdar
- Laboratory of Biochemistry, National Cancer Institute, Bethesda, Maryland 20892
| | | | | | | |
Collapse
|
41
|
Vil'ner LM, Kogan EM, Naumovich NG, Sidorova NS, Glazunov EA. [Dependence of the antiviral activity of the poly(G).poly(C) complex on the size of the continuous poly(C)segments]. Vopr Virusol 1988; 33:331-5. [PMID: 2845672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Modification of poly(C) by various frequency treatment with adenosine non-complementary to guanosine has produced poly(G) X poly (C.A) complexes with continuous double-stranded areas the length of which is determined by C/A ratio. Studies of the antiviral activity of poly(G).poly(C,A) complexes with C/A from 10:1 to 90:1 and poly(G).poly(C) in vesicular stomatitis virus-infected chick embryo cell cultures and in experimental tick-borne encephalitis of mice demonstrated that the maximum activity is achieved at an average lengths of double-stranded areas of 90 nucleotide pairs. At the same time, a low but statistically significant antiviral activity is observed at a length of double-stranded areas of 10-30 nucleotide pairs.
Collapse
|
42
|
Kortsaris A. 2', 5' oligo (A) synthetase levels in interferon-sensitive or resistant breast cancer cells. Microbiologica 1988; 11:111-7. [PMID: 3405096] [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: 01/05/2023]
Abstract
The levels of 2', 5' oligo (A) synthetase increase 15-fold when T47D cells are treated with human interferon or with interferon inducers. The results also show that interferon-treated T47D cells contain high levels of 2', 5' oligo (A) synthetase which upon incubation with ATP produces adenine oligonucleotides which are predominantly trimers. In contrast, MCF-7 and BT20 cells whether treated with interferon or not exhibit low 2', 5' oligo (A) synthetase activity.
Collapse
Affiliation(s)
- A Kortsaris
- Theagenion Memorial Cancer Institute, Greece
| |
Collapse
|
43
|
Concha II, Koide SS, Burzio LO. Characteristics of the inhibition of poly(ADP-ribose) glycohydrolase by homopolypurines. Biochem Int 1988; 16:397-403. [PMID: 3382411] [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: 01/05/2023]
Abstract
Poly(ADP-ribose) glycohydrolase partially purified from rat testis was markedly inhibited by the homopolypurines polyG, polyI and polyA. The inhibition was competitive with respect to poly(ADP-ribose) and the Ki for polyG and polyA was 2.8 uM and 5.5 uM, respectively. This inhibitory effect of the homopolypurines was practically eliminated when 250 mM KCl was present in the reaction mixture. Moreover, the inhibition exerted by polyI or polyA was markedly diminished after hybridization with polyC or polyT, respectively.
Collapse
Affiliation(s)
- I I Concha
- Instituto de Bioquimica, Facultad de Ciencias, Universidad Austral de Chile, Valdivia
| | | | | |
Collapse
|
44
|
Simon S, Vered M, Rinehart A, Cheronis J, Janoff A. Inhibition of human neutrophil elastase by polyguanylic acid and other synthetic polynucleotides. Adv Exp Med Biol 1988; 240:65-74. [PMID: 3245506 DOI: 10.1007/978-1-4613-1057-0_7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- S Simon
- Department of Biochemistry, SUNY, Stony Brook 11794
| | | | | | | | | |
Collapse
|
45
|
Nosik DN, Korneeva MN, Korsun NS, Maĭorova SN, Parshina OV. [The search for preparations suppressing the reproduction of the AIDS virus]. Vopr Virusol 1988; 33:34-7. [PMID: 3369147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Trials of clinically advantageous national inducers, thymus hormones, as well as human recombinant alpha 2-interferon were carried out in cultures of continuous lymphoblastoid cells H9/IIIB infected with HIV virus. The virus-inhibiting effect for HIV was observed with interferon in doses of 10-100 IU/ml. At a concentration of interferon of 1000 IU/ml, virus replication was inhibited completely, the interferon doses used exerting no marked toxic or antiproliferative effect on the cells. Human interferon inducers, poly(G).poly(C), PXL-6, dsRNA in concentrations of 50-100 micrograms/ml inhibited virus reproduction significantly. The highest antiviral effect was achieved with yeast dsRNA. The preparations of immunomodulators, thymarin, the 5th and 7th fractions of thymosin, noticeably stimulated proliferation of infected T-lymphocytes, reducing the relative number of cells carrying the virus-specific antigen. Combined use of preparations with different mechanisms of the antiviral effect may be advantageous in prevention and treatment of AIDS.
Collapse
|
46
|
Grigorian SS, Ershov FI, Poverennyĭ AM, Popov GA, Podgorodnichenko VK. [Characteristics of interferon production from the enteral administration of inducers]. Vopr Virusol 1988; 33:67-70. [PMID: 2453100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
When interferon inducers are administered to animals, autonomous local production of interferon by organs (intestine, liver) occurs alongside with the production of serum interferon. After oral administration of a low molecular interferon inducer, tilorone, the intestine is the main site of interferon synthesis. Here the peak of interferon production precedes that in the serum by 20 hours and exceeds it 16-fold. The sequence of events follows the scheme: intestine--liver--serum. Upon oral administration of high molecular inducers incorporated into liposomes (polyguacyl, lafarin) the predominant site of interferon production is the liver where over 80% of the administered inducer is localized and interferon production is 2-4-fold higher than in the intestine. The sequence of events follows the scheme: liver--intestine--serum.
Collapse
|
47
|
Dick RS, Hubbell HR. Sensitivities of human glioma cell lines to interferons and double-stranded RNAs individually and in synergistic combinations. J Neurooncol 1987; 5:331-8. [PMID: 2450181 DOI: 10.1007/bf00148390] [Citation(s) in RCA: 15] [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: 01/01/2023]
Abstract
The antiproliferative effects of human interferons (IFNs) and double-stranded RNAs (dsRNAs) were studied in five human glioma cell lines. Dose response curves were generated over a 72 hour treatment period. The concentration of interferon or double-stranded RNA necessary to produce a 50% antiproliferative response (GI50) was calculated by linear regression analysis. Two cell lines were more sensitive to IFN-beta than to IFN-alpha, one cell line was more sensitive to IFN-alpha than to IFN-beta and two cell lines had approximately equal sensitivities to both interferons. All cell lines showed some sensitivity to either IFN-alpha or IFN-beta. IFN-gamma had no antiproliferative effect on any of the cell lines. In addition, only one of the cell lines displayed sensitivity to dsRNA, in which the response to poly(I).poly(C) was greater than that to a mismatched analogue of poly(I).poly(C), r(I)n.r(C12,U)n (Ampligen). There was no correlation between the sensitivities to type I IFNs (alpha and beta), type II IFN (gamma) or the dsRNAs. The antiproliferative effect of combinations of IFNs, or IFNs and Ampligen, was studied in one of the cell lines. A significant synergistic antitumor effect was seen with all of the IFN/Ampligen combinations (p less than 0.02), including IFN-gamma/Ampligen, even though these cells were resistant to IFN-gamma alone. Synergy was also seen in the IFN-alpha/IFN-gamma (p less than 0.02) and IFN-beta/IFN-gamma (p less than 0.05) combinations. The IFN-alpha/IFN-beta combination gave an additive antitumor effect. These results indicate that IFN-alpha and IFN-beta alone or combinations of type I IFNs, type II IFNs and Ampligen can be effective in inhibiting the growth of glioma cells.
Collapse
Affiliation(s)
- R S Dick
- Department of Neoplastic Diseases, Hahnemann University, Philadelphia, PA 19102
| | | |
Collapse
|
48
|
Grigorian SS, Ershov FI, Poverennyĭ AM, Podgorodnichenko VK, Popov GA. [Interferon-inducing activity of liposome-incorporated double-stranded polynucleotides and the means for its enhancement]. Vopr Virusol 1987; 32:352-7. [PMID: 2445111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Natural double-stranded RNA (dsRNA) incorporated into liposomes upon parenteral inoculation induces 4 times as much amounts of interferon as inoculation of the equal amount of dsRNA without liposomes. Oral administration of liposome-incorporated dsRNA induces in animals serum interferon in amounts similar to those induced by parenteral inoculation of dsRNA without liposomes (320-640 units/ml). When liposome-incorporated dsRNA is used, interferon induction is prolonged to 24 hours. The prolongation period increases to 5 days after preliminary treatment of animals with "empty" liposomes. In M-19 cell culture, 2-hour treatment with liposome-incorporated dsRNA in a dose of 5-10 micrograms/ml induces a yield of 640-1280 units/ml interferon and 100% antiviral effect. The L-929 culture is more sensitive to dsRNA in liposomes. Even its minimal amounts (0.1-1 microgram/ml) after 2-3-hour contact produce a 100% antiviral effect in the presence of low amounts of interferon in the culture fluid (20-40 units/ml) or in its complete absence.
Collapse
|
49
|
Ershov FI, Kadyrova AA. [Activity of synthetic poly-L-lysine-coated polynucleotides]. Vopr Virusol 1987; 32:366-9. [PMID: 2445112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
|
50
|
Abstract
Azotobacter vinelandii NMN glycohydrolase [EC 3.2.2.14] has been shown to require absolutely GTP or a high-molecular-weight and heat-stable component for its function. The intracellular activator could be purified from its sonicate by heat treatment, acetone precipitation, phenol extraction, and acid precipitation in a good yield. The purified activator showed high affinity and effectiveness for NMN glycohydrolase (KA = 0.012 optical density unit at 257 nm/ml; Vmax standardized by the activity at 1 mM GTP = 88%). Negative cooperativity of the enzyme activation with the activator was also shown. On treatment with either micrococcal nuclease or pancreatic RNase, the activator activity was completely abolished, whereas pronase and trypsin had no effect. The activator could be replaced by yeast RNA as well as calf liver RNA, whereas DNAs purified from Micrococcus lysodeikticus, T 7 and calf thymus had no effect on the enzyme. Furthermore, poly(G) and poly(I) could function as activators with the same effectiveness as the purified activator, and the enzyme activation with these RNA homopolymers was inhibited by poly(C), suggesting that the activation mechanism is specific with respect to base composition. Based on a kinetic analysis of the enzyme activation with commercial RNAs, together with the results from enzymatic digestion, specific inhibition of the enzyme by spermine, and its chemical properties, the activator was identified as an RNA. A model is described for NMN glycohydrolase regulation in which the RNA activator plays an important role in the NMN salvage cycles.
Collapse
|