1
|
Bynoe K, Unwin N, Taylor C, Murphy MM, Bartholomew L, Greenidge A, Abed M, Jeyaseelan S, Cobelli C, Dalla Man C, Taylor R. Inducing remission of Type 2 diabetes in the Caribbean: findings from a mixed methods feasibility study of a low-calorie liquid diet-based intervention in Barbados. Diabet Med 2020; 37:1816-1824. [PMID: 31365159 DOI: 10.1111/dme.14096] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [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] [Accepted: 07/29/2019] [Indexed: 01/04/2023]
Abstract
AIM In a high proportion of people with recently diagnosed Type 2 diabetes, a short (2-3-month) low-calorie diet is able to restore normal glucose and insulin metabolism. The aim of this study was to determine the feasibility of this approach in Barbados. METHODS Twenty-five individuals with Type 2 diabetes diagnosed within past 6 years, not on insulin, BMI ≥ 27 kg/m2 were recruited. Hypoglycaemic medication was stopped on commencement of the 8-week liquid (760 calorie) diet. Insulin response was assessed in meal tests at baseline, 8 weeks and 8 months. Semi-structured interviews, analysed thematically, explored participants' experiences. 'Responders' were those with fasting plasma glucose (FPG) < 7 mmol/l at 8 weeks. RESULTS Ten men and 15 women (mean age 48, range 26-68 years) participated. Mean (sd) BMI was 34.2 kg/m2 (6.0); FPG 9.2 mmol/l (2.2). Mean weight loss at 8 weeks and 8 months was 10.1 kg [95% confidence interval (CI) 8.1, 12.0] and 8.2 kg (95% CI 5.8, 10.6); FPG was lower by 2.2 mmol/l (95% CI 1.2, 3.2) and 1.7 mmol/l (95% CI 0.8, 2.7) respectively. Nine of 11 (82%) of those who lost ≥ 10 kg were 'responders' compared with 6 of 14 (43%) who lost < 10 kg (P = 0.048). The 30-min insulin increment was higher in responders at baseline and follow-up (P ≤ 0.01). A food culture based on starchy foods and pressures to eat large amounts at social events were among the challenges identified by participants. CONCLUSIONS The feasibility of this approach to weight loss and diabetes remission in a predominantly black population in Barbados was demonstrated.
Collapse
Affiliation(s)
- K Bynoe
- George Alleyne Chronic Disease Research Centre, Caribbean Institute for Health Research, University of the West Indies, Barbados
| | - N Unwin
- George Alleyne Chronic Disease Research Centre, Caribbean Institute for Health Research, University of the West Indies, Barbados
- MRC Epidemiology Unit, University of Cambridge, Cambridge, UK
| | - C Taylor
- Department of Medicine, University of the West Indies, Barbados
| | - M M Murphy
- Public Health Group, Faculty of Medical Sciences, University of Padova, Italy
| | - L Bartholomew
- Public Health Group, Faculty of Medical Sciences, University of Padova, Italy
| | - A Greenidge
- George Alleyne Chronic Disease Research Centre, Caribbean Institute for Health Research, University of the West Indies, Barbados
| | - M Abed
- George Alleyne Chronic Disease Research Centre, Caribbean Institute for Health Research, University of the West Indies, Barbados
| | - S Jeyaseelan
- George Alleyne Chronic Disease Research Centre, Caribbean Institute for Health Research, University of the West Indies, Barbados
| | - C Cobelli
- Department of Information Engineering, University of Padova, Italy
| | - C Dalla Man
- Department of Information Engineering, University of Padova, Italy
| | - R Taylor
- Newcastle Magnetic Resonance Centre, Newcastle University, Newcastle, UK
| |
Collapse
|
2
|
Stade BC, Watson W, Bonifacio J, McCleod HJ, Barozzino T, DiMarchi A, Becker B, Bartholomew L, Sgro M. 129: Diagnosing Fetal Alcohol Spectrum Disorder, the Need for Genetic Testing: A Pilot Study. Paediatr Child Health 2014. [DOI: 10.1093/pch/19.6.e35-127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
3
|
Estrabillo E, Perwez M, McFadyen K, Bartholomew L, Campbell D. Iron Status in Low Birth Weight Preterm and Near-Term Infants. Paediatr Child Health 2012. [DOI: 10.1093/pch/17.suppl_a.14ab] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
4
|
Estrabillo E, McFadyen K, Westergard S, Bartholomew L, McLaren A, Campbell D. Iron Status In Low Birth Weight Preterm and Near-Term Infants. Paediatr Child Health 2010. [DOI: 10.1093/pch/15.suppl_a.17ab] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
|
5
|
Estrabillo E, McFayden K, Westergaard S, Bartholomew L, Campbell DM. Iron Status in Low Birth Weight Preterm and Near-Term Infants. Paediatr Child Health 2009. [DOI: 10.1093/pch/14.suppl_a.30aa] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
6
|
Pacini L, Bartholomew L, Vitelli A, Migliaccio G. Reporter substrates for assessing the activity of the hepatitis C virus NS3-4A serine protease in living cells. Anal Biochem 2005; 331:46-59. [PMID: 15245996 DOI: 10.1016/j.ab.2004.04.027] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2003] [Indexed: 09/30/2022]
Abstract
We describe a versatile system for monitoring the activity of the NS3-4A serine protease of the hepatitis C virus (HCV) in mammalian cells. The system relies on coexpression of the protease and of an artificial substrate containing a reporter domain and an intracellular targeting sequence separated by a NS3-4A-specific cleavage site. We constructed two different substrates suitable for different applications. The first substrate secretory alkaline phosphatase-1 (SEAP-1) harbors the NS3-4A cleavage site inserted between the SEAP and a membrane anchor featuring an endoplasmic reticulum retention sequence. The arrangement of this substrate is such that SEAP is secreted in the extracellular medium depending on the NS3 protease activity. We show that SEAP-1 can be used to evaluate the activity of NS3-4A inhibitors in living cells. In the second substrate (CD8-1), SEAP is replaced by the extracellular domain of the lymphocyte surface antigen CD8 alpha. The arrangement of this substrate is such that the CD8 alpha domain is transported to the cell surface upon NS3-4Ap cleavage and remains associated with the plasma membrane as an integral membrane protein. We show that CD8-1 can be used for selecting cells capable of supporting HCV replication.
Collapse
Affiliation(s)
- Laura Pacini
- IRBM P. Angeletti, Via Pontina km 30.600, 00040 Pomezia, Rome, Italy
| | | | | | | |
Collapse
|
7
|
Neddermann P, Quintavalle M, Di Pietro C, Clementi A, Cerretani M, Altamura S, Bartholomew L, De Francesco R. Reduction of hepatitis C virus NS5A hyperphosphorylation by selective inhibition of cellular kinases activates viral RNA replication in cell culture. J Virol 2004; 78:13306-14. [PMID: 15542681 PMCID: PMC524975 DOI: 10.1128/jvi.78.23.13306-13314.2004] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.4] [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: 12/12/2022] Open
Abstract
Efficient replication of hepatitis C virus (HCV) subgenomic RNA in cell culture requires the introduction of adaptive mutations. In this report we describe a system which enables efficient replication of the Con1 subgenomic replicon in Huh7 cells without the introduction of adaptive mutations. The starting hypothesis was that high amounts of the NS5A hyperphosphorylated form, p58, inhibit replication and that reduction of p58 by inhibition of specific kinase(s) below a certain threshold enables HCV replication. Upon screening of a panel of kinase inhibitors, we selected three compounds which inhibited NS5A phosphorylation in vitro and the formation of NS5A p58 in cell culture. Cells, transfected with the HCV Con1 wild-type sequence, support HCV RNA replication upon addition of any of the three compounds. The effect of the kinase inhibitors was found to be synergistic with coadaptive mutations in NS3. This is the first direct demonstration that the presence of high amounts of NS5A-p58 causes inhibition of HCV RNA replication in cell culture and that this inhibition can be relieved by kinase inhibitors.
Collapse
|
8
|
Olsen DB, Eldrup AB, Bartholomew L, Bhat B, Bosserman MR, Ceccacci A, Colwell LF, Fay JF, Flores OA, Getty KL, Grobler JA, LaFemina RL, Markel EJ, Migliaccio G, Prhavc M, Stahlhut MW, Tomassini JE, MacCoss M, Hazuda DJ, Carroll SS. A 7-deaza-adenosine analog is a potent and selective inhibitor of hepatitis C virus replication with excellent pharmacokinetic properties. Antimicrob Agents Chemother 2004; 48:3944-53. [PMID: 15388457 PMCID: PMC521892 DOI: 10.1128/aac.48.10.3944-3953.2004] [Citation(s) in RCA: 177] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/09/2022] Open
Abstract
Improved treatments for chronic hepatitis C virus (HCV) infection are needed due to the suboptimal response rates and deleterious side effects associated with current treatment options. The triphosphates of 2'-C-methyl-adenosine and 2'-C-methyl-guanosine were previously shown to be potent inhibitors of the HCV RNA-dependent RNA polymerase (RdRp) that is responsible for the replication of viral RNA in cells. Here we demonstrate that the inclusion of a 7-deaza modification in a series of purine nucleoside triphosphates results in an increase in inhibitory potency against the HCV RdRp and improved pharmacokinetic properties. Notably, incorporation of the 7-deaza modification into 2'-C-methyl-adenosine results in an inhibitor with a 20-fold-increased potency as the 5'-triphosphate in HCV RdRp assays while maintaining the inhibitory potency of the nucleoside in the bicistronic HCV replicon and with reduced cellular toxicity. In contrast, while 7-deaza-2'-C-methyl-GTP also displays enhanced inhibitory potency in enzyme assays, due to poor cellular penetration and/or metabolism, the nucleoside does not inhibit replication of a bicistronic HCV replicon in cell culture. 7-Deaza-2'-C-methyl-adenosine displays promising in vivo pharmacokinetics in three animal species, as well as an acute oral lethal dose in excess of 2,000 mg/kg of body weight in mice. Taken together, these data demonstrate that 7-deaza-2'-C-methyl-adenosine is an attractive candidate for further investigation as a potential treatment for HCV infection.
Collapse
Affiliation(s)
- David B Olsen
- Department of Biological Chemistry, Merck Research Laboratories, West Point, Pennsylvania 19486, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Tomei L, Altamura S, Bartholomew L, Bisbocci M, Bailey C, Bosserman M, Cellucci A, Forte E, Incitti I, Orsatti L, Koch U, De Francesco R, Olsen DB, Carroll SS, Migliaccio G. Characterization of the inhibition of hepatitis C virus RNA replication by nonnucleosides. J Virol 2004; 78:938-46. [PMID: 14694125 PMCID: PMC368780 DOI: 10.1128/jvi.78.2.938-946.2004] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.0] [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: 11/20/2022] Open
Abstract
The RNA-dependent RNA polymerase of hepatitis C virus (HCV) is necessary for the replication of viral RNA and thus represents an attractive target for drug development. Several structural classes of nonnucleoside inhibitors (NNIs) of HCV RNA polymerase have been described, including a promising series of benzothiadiazine compounds that efficiently block replication of HCV subgenomic replicons in tissue culture. In this work we report the selection of replicons resistant to inhibition by the benzothiadiazine class of NNIs. Four different single mutations were identified in separate clones, and all four map to the RNA polymerase gene, validating the polymerase as the antiviral target of inhibition. The mutations (M414T, C451R, G558R, and H95R) render the HCV replicons resistant to inhibition by benzothiadiazines, though the mutant replicons remain sensitive to inhibition by other nucleoside and NNIs of the HCV RNA polymerase. Additionally, cross-resistance studies and synergistic inhibition of the enzyme by combinations of a benzimidazole and a benzothiadiazine indicate the existence of nonoverlapping binding sites for these two structural classes of inhibitors.
Collapse
Affiliation(s)
- Licia Tomei
- Department of Biochemistry, Istituto di Ricerche di Biologia Molecolare P. Angeletti (IRBM), Pomezia, Italy
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Tomei L, Altamura S, Bartholomew L, Biroccio A, Ceccacci A, Pacini L, Narjes F, Gennari N, Bisbocci M, Incitti I, Orsatti L, Harper S, Stansfield I, Rowley M, De Francesco R, Migliaccio G. Mechanism of action and antiviral activity of benzimidazole-based allosteric inhibitors of the hepatitis C virus RNA-dependent RNA polymerase. J Virol 2004; 77:13225-31. [PMID: 14645579 PMCID: PMC296079 DOI: 10.1128/jvi.77.24.13225-13231.2003] [Citation(s) in RCA: 162] [Impact Index Per Article: 8.1] [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: 11/20/2022] Open
Abstract
The RNA-dependent RNA polymerase of hepatitis C virus (HCV) is the catalytic subunit of the viral RNA amplification machinery and is an appealing target for the development of new therapeutic agents against HCV infection. Nonnucleoside inhibitors based on a benzimidazole scaffold have been recently reported. Compounds of this class are efficient inhibitors of HCV RNA replication in cell culture, thus providing attractive candidates for further development. Here we report the detailed analysis of the mechanism of action of selected benzimidazole inhibitors. Kinetic data and binding experiments indicated that these compounds act as allosteric inhibitors that block the activity of the polymerase prior to the elongation step. Escape mutations that confer resistance to these compounds map to proline 495, a residue located on the surface of the polymerase thumb domain and away from the active site. Substitution of this residue is sufficient to make the HCV enzyme and replicons resistant to the inhibitors. Interestingly, proline 495 lies in a recently identified noncatalytic GTP-binding site, thus validating it as a potential allosteric site that can be targeted by small-molecule inhibitors of HCV polymerase.
Collapse
Affiliation(s)
- Licia Tomei
- Istituto di Ricerche di Biologia Molecolare "P. Angeletti," 00040 Pomezia-Rome, Italy.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Migliaccio G, Tomassini JE, Carroll SS, Tomei L, Altamura S, Bhat B, Bartholomew L, Bosserman MR, Ceccacci A, Colwell LF, Cortese R, De Francesco R, Eldrup AB, Getty KL, Hou XS, LaFemina RL, Ludmerer SW, MacCoss M, McMasters DR, Stahlhut MW, Olsen DB, Hazuda DJ, Flores OA. Characterization of resistance to non-obligate chain-terminating ribonucleoside analogs that inhibit hepatitis C virus replication in vitro. J Biol Chem 2003; 278:49164-70. [PMID: 12966103 DOI: 10.1074/jbc.m305041200] [Citation(s) in RCA: 286] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The urgent need for efficacious drugs to treat chronic hepatitis C virus (HCV) infection requires a concerted effort to develop inhibitors specific for virally encoded enzymes. We demonstrate that 2'-C-methyl ribonucleosides are efficient chain-terminating inhibitors of HCV genome replication. Characterization of drug-resistant HCV replicons defined a single S282T mutation within the active site of the viral polymerase that conferred loss of sensitivity to structurally related compounds in both replicon and isolated polymerase assays. Biochemical analyses demonstrated that resistance at the level of the enzyme results from a combination of reduced affinity of the mutant polymerase for the drug and an increased ability to extend the incorporated nucleoside analog. Importantly, the combination of these agents with interferon-alpha results in synergistic inhibition of HCV genome replication in cell culture. Furthermore, 2'-C-methyl-substituted ribonucleosides also inhibited replication of genetically related viruses such as bovine diarrhea virus, yellow fever, and West African Nile viruses. These observations, together with the finding that 2'-C-methyl-guanosine in particular has a favorable pharmacological profile, suggest that this class of compounds may have broad utility in the treatment of HCV and other flavivirus infections.
Collapse
Affiliation(s)
- Giovanni Migliaccio
- Department of Biochemistry, Istituto di Ricerche di Biologia Molecolare P. Angeletti (IRBM), 00040 Pomezia, Italy
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Trozzi C, Bartholomew L, Ceccacci A, Biasiol G, Pacini L, Altamura S, Narjes F, Muraglia E, Paonessa G, Koch U, De Francesco R, Steinkuhler C, Migliaccio G. In vitro selection and characterization of hepatitis C virus serine protease variants resistant to an active-site peptide inhibitor. J Virol 2003; 77:3669-79. [PMID: 12610142 PMCID: PMC149541 DOI: 10.1128/jvi.77.6.3669-3679.2003] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2002] [Accepted: 12/13/2002] [Indexed: 01/08/2023] Open
Abstract
The hepatitis C virus (HCV) serine protease is necessary for viral replication and represents a valid target for developing new therapies for HCV infection. Potent and selective inhibitors of this enzyme have been identified and shown to inhibit HCV replication in tissue culture. The optimization of these inhibitors for clinical development would greatly benefit from in vitro systems for the identification and the study of resistant variants. We report the use HCV subgenomic replicons to isolate and characterize mutants resistant to a protease inhibitor. Taking advantage of the replicons' ability to transduce resistance to neomycin, we selected replicons with decreased sensitivity to the inhibitor by culturing the host cells in the presence of the inhibitor and neomycin. The selected replicons replicated to the same extent as those in parental cells. Sequence analysis followed by transfection of replicons containing isolated mutations revealed that resistance was mediated by amino acid substitutions in the protease. These results were confirmed by in vitro experiments with mutant enzymes and by modeling the inhibitor in the three-dimensional structure of the protease.
Collapse
|
13
|
Mottola G, Cardinali G, Ceccacci A, Trozzi C, Bartholomew L, Torrisi MR, Pedrazzini E, Bonatti S, Migliaccio G. Hepatitis C virus nonstructural proteins are localized in a modified endoplasmic reticulum of cells expressing viral subgenomic replicons. Virology 2002; 293:31-43. [PMID: 11853397 DOI: 10.1006/viro.2001.1229] [Citation(s) in RCA: 138] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
For many years our knowledge on hepatitis C virus (HCV) replication has been based on in vitro experiments or transfection studies. Recently, the first reliable system for studying viral replication in tissue culture cells was developed. Taking advantage of this system, we examined in detail the localization of viral nonstructural (NS) proteins in cells containing functional replication complexes. By fractionation experiments and immunomicroscopy, we observed that all NS proteins were associated with the endoplasmic reticulum (ER) membranes, confirming the hypothesis that the ER is the site of membrane-associated HCV RNA replication. Interestingly, NS3 and NS4A were preferentially localized in endoplasmic reticulum cisternae surrounding mitochondria, suggesting additional subcellular compartment-related functions for these viral proteins. Furthermore, the immunoelectron microscopy revealed the loss of the organization and other morphological alterations of the ER (convoluted cisternae and paracrystalline structures), resembling alterations observed in liver biopsies of HCV-infected individuals and in flavivirus-infected cells.
Collapse
Affiliation(s)
- Giovanna Mottola
- Dipartimento di Biochemie e Biotecnologie, Università de Napoli Federico II, Naples, Italy
| | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Pacini L, Vitelli A, Filocamo G, Bartholomew L, Brunetti M, Tramontano A, Steinkühler C, Migliaccio G. In vivo selection of protease cleavage sites by using chimeric Sindbis virus libraries. J Virol 2000; 74:10563-70. [PMID: 11044100 PMCID: PMC110930 DOI: 10.1128/jvi.74.22.10563-10570.2000] [Citation(s) in RCA: 12] [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] [Received: 05/15/2000] [Accepted: 08/15/2000] [Indexed: 11/20/2022] Open
Abstract
Identifying protease cleavage sites contributes to our understanding of their specificity and biochemical properties and can help in designing specific inhibitors. One route to this end is the generation and screening of random libraries of cleavage sites. Both synthetic and phage-displayed libraries have been extensively used in vitro. We describe a novel system based on recombinant Sindbis virus which can be used to identify cleavage sites in vivo, thus eliminating the need for a purified enzyme and overcoming the problem of choosing the correct in vitro conditions. As a model we used the serine protease of the hepatitis C virus (HCV). We engineered the gene coding for this enzyme and two specific cleavage sites in the Sindbis virus structural gene and constructed libraries of viral genomes with a random sequence at either of the cleavage sites. The system was designed so that only viral genomes coding for sequences cleaved by the protease would produce viable viruses. With this system we selected viruses containing sequences mirroring those of the natural HCV protease substrates which were cleaved with comparable efficiencies.
Collapse
Affiliation(s)
- L Pacini
- Istituto di Ricerche di Biologia Molecolare P. Angeletti, 00040 Pomezia (Rome), Italy
| | | | | | | | | | | | | | | |
Collapse
|
15
|
Filocamo G, Pacini L, Nardi C, Bartholomew L, Scaturro M, Delmastro P, Tramontano A, De Francesco R, Migliaccio G. Selection of functional variants of the NS3-NS4A protease of hepatitis C virus by using chimeric sindbis viruses. J Virol 1999; 73:561-75. [PMID: 9847361 PMCID: PMC103862 DOI: 10.1128/jvi.73.1.561-575.1999] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The NS3-NS4A serine protease of hepatitis C virus (HCV) mediates four specific cleavages of the viral polyprotein and its activity is considered essential for the biogenesis of the HCV replication machinery. Despite extensive biochemical and structural characterization, the analysis of natural variants of this enzyme has been limited by the lack of an efficient replication system for HCV in cultured cells. We have recently described the generation of chimeric HCV-Sindbis viruses whose propagation depends on the NS3-NS4A catalytic activity. NS3-NS4A gene sequences were fused to the gene coding for the Sindbis virus structural polyprotein in such a way that processing of the chimeric polyprotein, nucleocapsid assembly, and production of infectious viruses required NS3-NS4A-mediated proteolysis (G. Filocamo, L. Pacini, and G. Migliaccio, J. Virol. 71:1417-1427, 1997). Here we report the use of these chimeric viruses to select and characterize active variants of the NS3-NS4A protease. Our original chimeric viruses displayed a temperature-sensitive phenotype and formed lysis plaques much smaller than those formed by wild-type (wt) Sindbis virus. By serially passaging these chimeric viruses on BHK cells, we have selected virus variants which formed lysis plaques larger than those produced by their progenitors and produced NS3-NS4A proteins different in size and/or sequence from those of the original viruses. Characterization of the selected protease variants revealed that all of the mutated proteases still efficiently processed the chimeric polyprotein in infected cells and also cleaved an HCV substrate in vitro. One of the selected proteases was expressed in a bacterial system and showed a catalytic efficiency comparable to that of the wt recombinant protease.
Collapse
Affiliation(s)
- G Filocamo
- Istituto di Ricerche di Biologia Molecolare P. Angeletti, 00040 Pomezia, Rome, Italy
| | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Giordano V, De Falco G, Chiari R, Quinto I, Pelicci PG, Bartholomew L, Delmastro P, Gadina M, Scala G. Shc mediates IL-6 signaling by interacting with gp130 and Jak2 kinase. The Journal of Immunology 1997. [DOI: 10.4049/jimmunol.158.9.4097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
IL-6 is a multifunctional cytokine involved in hemopoiesis, immune regulation, inflammation, neural development, and infection. IL-6 belongs to a family of related cytokines that includes leukemia inhibitory factor, oncostatin M, IL-11, ciliary neurotropic factor, and cardiotropin-1, all of which initiate signaling through a receptor-associated gp130. IL-6 induces homodimerization of gp130 and activates the Jak/STAT pathway of signal transduction. In addition, IL-6 stimulates the mitogen-activated protein kinases designated ERK (extracellular signal-regulated kinase)-1 and -2. Activation of ERK-1 and -2 may involve the Src homology-2 containing proteins Shc and Grb2. Here we provide evidence that Shc could function as signaling molecules for IL-6 in DeFew-IL-6R/gp130 cells, a human B lymphoma cell line engineered to express high levels of both the IL-6R (p80) and the gp130 subunit. IL-6 was shown to promote the rapid tyrosine phosphorylation of gp130, Jak2, and Shc proteins. Moreover, Shc associated both in vivo and in vitro with phosphorylated gp130 through the Shc-Src homology-2 domain. We also report that Shc bound to activated Jak2 by using the Shc amino terminal phosphotyrosine interaction domain. Following IL-6 stimulation, Shc physically associated with Grb2. Thus, the data point to Shc proteins as a functional link between the Jak2 and Ras pathways of IL-6 signal transduction.
Collapse
Affiliation(s)
- V Giordano
- Department of Biochemistry and Biomedical Technology, Medical School, University Federico II, Naples, Italy
| | - G De Falco
- Department of Biochemistry and Biomedical Technology, Medical School, University Federico II, Naples, Italy
| | - R Chiari
- Department of Biochemistry and Biomedical Technology, Medical School, University Federico II, Naples, Italy
| | - I Quinto
- Department of Biochemistry and Biomedical Technology, Medical School, University Federico II, Naples, Italy
| | - P G Pelicci
- Department of Biochemistry and Biomedical Technology, Medical School, University Federico II, Naples, Italy
| | - L Bartholomew
- Department of Biochemistry and Biomedical Technology, Medical School, University Federico II, Naples, Italy
| | - P Delmastro
- Department of Biochemistry and Biomedical Technology, Medical School, University Federico II, Naples, Italy
| | - M Gadina
- Department of Biochemistry and Biomedical Technology, Medical School, University Federico II, Naples, Italy
| | - G Scala
- Department of Biochemistry and Biomedical Technology, Medical School, University Federico II, Naples, Italy
| |
Collapse
|
17
|
Giordano V, De Falco G, Chiari R, Quinto I, Pelicci PG, Bartholomew L, Delmastro P, Gadina M, Scala G. Shc mediates IL-6 signaling by interacting with gp130 and Jak2 kinase. J Immunol 1997; 158:4097-103. [PMID: 9126968] [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: 02/04/2023]
Abstract
IL-6 is a multifunctional cytokine involved in hemopoiesis, immune regulation, inflammation, neural development, and infection. IL-6 belongs to a family of related cytokines that includes leukemia inhibitory factor, oncostatin M, IL-11, ciliary neurotropic factor, and cardiotropin-1, all of which initiate signaling through a receptor-associated gp130. IL-6 induces homodimerization of gp130 and activates the Jak/STAT pathway of signal transduction. In addition, IL-6 stimulates the mitogen-activated protein kinases designated ERK (extracellular signal-regulated kinase)-1 and -2. Activation of ERK-1 and -2 may involve the Src homology-2 containing proteins Shc and Grb2. Here we provide evidence that Shc could function as signaling molecules for IL-6 in DeFew-IL-6R/gp130 cells, a human B lymphoma cell line engineered to express high levels of both the IL-6R (p80) and the gp130 subunit. IL-6 was shown to promote the rapid tyrosine phosphorylation of gp130, Jak2, and Shc proteins. Moreover, Shc associated both in vivo and in vitro with phosphorylated gp130 through the Shc-Src homology-2 domain. We also report that Shc bound to activated Jak2 by using the Shc amino terminal phosphotyrosine interaction domain. Following IL-6 stimulation, Shc physically associated with Grb2. Thus, the data point to Shc proteins as a functional link between the Jak2 and Ras pathways of IL-6 signal transduction.
Collapse
Affiliation(s)
- V Giordano
- Department of Biochemistry and Biomedical Technology, Medical School, University Federico II, Naples, Italy
| | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Bartholomew L, Schneiderman LJ. Attitudes of patients toward family care in a family practice group. J Fam Pract 1982; 15:477-481. [PMID: 7108462] [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: 05/21/2023]
Abstract
There is little information documenting the extent to which the ideal of whole family care is represented in the real world of family practice. A previous study of a suburban family practice group revealed that only 28 percent of families obtained whole family care from a single physician. Interviews were conducted on a sample of 97 of these patients in an effort to gain insights into the factors influencing the choice of a single physician or more than one physician providing their health care. There were no significant differences between same-physician and different-physician families with respect to demographic factors or attitudes toward physician characteristics and family care. Most families had no insights into the potential value of having a single physician for the whole family; indeed, only one family specifically selected a single physician with the belief that it would thereby gain better care. If the observations reported here are representative of the situation at large in the country, family physicians have an important task ahead in patient education.
Collapse
|
19
|
Kisch AL, Bartholomew L. Comparison of the in vitro activity of several cephalosporin antibiotics against gram-negative and gram-positive bacteria resistant to cephaloridine. Antimicrob Agents Chemother 1976; 10:507-10. [PMID: 984793 PMCID: PMC429780 DOI: 10.1128/aac.10.3.507] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The in vitro activity of each of two oral [cefatrizine (BL-S640), cephalexin] and three parenteral (cefamandole, cefazolin, cephapirin) cephalosporin antibiotics was compared with that of cephalothin against 168 clinical isolates of gram-negative and gram-positive bacteria selected as resistant to 20 mug of cephaloridine per ml on the basis of agar dilution susceptibility test data. Each of the five other cephalosporins inhibited a greater percentage of gram-negative bacillary isolates than did cephalothin or cephaloridine, with minimal inhibitory concentration values ranging 2- to 50-fold lower. Significant differences between minimal inhibitory concentrations of the compounds tested were also observed in tests against strains of Streptococcus faecalis and of methicillin-resistant Staphylococcus aureus. Potential advantages of including more than a single cephalosporin antibiotic in the panel of antibiotics used for routine susceptibility testing, suggested by these observations, are discussed.
Collapse
|
20
|
Bartholomew L, Mace KD. Isolation and identification of phospholipids from root tip cell plasmalemma of Phaseolus limensis. Cytobios 1972; 5:241-7. [PMID: 4349743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|