ABSTRACT
In the early phases of the SARS coronavirus type 2 (SARS-CoV-2) pandemic, testing focused on individuals fitting a strict case definition involving a limited set of symptoms together with an identified epidemiological risk, such as contact with an infected individual or travel to a high-risk area. To assess whether this impaired our ability to detect and control early introductions of the virus into the UK, we PCR-tested archival specimens collected on admission to a large UK teaching hospital who retrospectively were identified as having a clinical presentation compatible with COVID-19. In addition, we screened available archival specimens submitted for respiratory virus diagnosis, and dating back to early January 2020, for the presence of SARS-CoV-2 RNA. Our data provides evidence for widespread community circulation of SARS-CoV-2 in early February 2020 and into March that was undetected at the time due to restrictive case definitions informing testing policy. Genome sequence data showed that many of these early cases were infected with a distinct lineage of the virus. Sequences obtained from the first officially recorded case in Nottinghamshire - a traveller returning from Daegu, South Korea - also clustered with these early UK sequences suggesting acquisition of the virus occurred in the UK and not Daegu. Analysis of a larger sample of sequences obtained in the Nottinghamshire area revealed multiple viral introductions, mainly in late February and through March. These data highlight the importance of timely and extensive community testing to prevent future widespread transmission of the virus.
Subject(s)
COVID-19/diagnosis , COVID-19/virology , Respiratory System/virology , SARS-CoV-2/isolation & purification , Adult , Aged , COVID-19/epidemiology , COVID-19/transmission , COVID-19 Nucleic Acid Testing , Female , Humans , Male , Mass Screening/methods , Middle Aged , Phylogeny , RNA, Viral/genetics , Retrospective Studies , SARS-CoV-2/genetics , United Kingdom/epidemiologyABSTRACT
BACKGROUND: Genomic services are increasingly accessible to young adults starting their independent lives with responsibility for their self-care, yet their attitudes to sharing genomic information remain under-researched. This study explored attitudes of university-based 18-25 year-olds towards sharing personal whole-genome sequencing (WGS) information with relatives. METHODS: We surveyed 112 young adults. Hypotheses were tested regarding the relationships between their preferences for sharing personal WGS information with relatives and factors including their gender, previous genetics-specific education, general educational attainment level and current study in a science, technology, engineering, maths or medicine (STEMM) field. RESULTS: Most participants were positive about both their intention to share their WGS results with their parents and siblings, and their desire to know their relatives' results. Being female and having a university-level genetics education were consistently positively correlated with intention to share one's results with parents and with siblings as well as the desire to know relatives' results. Additionally, females who had undertaken a genetics course at university had significantly greater intentions and desires than females who had not. Lower general educational attainment was related to a lower intention to share with siblings. Participants who were in a STEMM field had a greater desire to know their relatives' results. CONCLUSIONS: Participants' gender and prior genetics education were consistently related to their intentions to share WGS results with relatives and their desire to know relatives' results. Educational attainment was found to be positively correlated with intention to share with siblings. Being in a STEMM field was related to participants' desire to know their relatives' results. These findings indicate that gender and genetics education are particularly important influencers on young adults' stated sharing preferences. More research is required to examine the dependent variables studied to further understand their influence on attitudes to sharing WGS results. These findings are particularly interesting for information provision and support before genomic sequencing and post-results to improve the outcomes for individuals and their relatives.
Subject(s)
Health Knowledge, Attitudes, Practice , Information Dissemination , Surveys and Questionnaires , Universities , Whole Genome Sequencing , Family , Female , Humans , Male , Policy Making , Young AdultABSTRACT
Prisons are a key demographic in the drive to eradicate hepatitis C virus (HCV) as a major public health threat. We have assessed the impact of the recently introduced national opt-out policy on the current status of HCV testing in 14 prisons in the East Midlands (UK). We analysed testing rates pre- and post-introduction of opt-out testing, together with face-to-face interviews with prison healthcare and management staff in each prison. In the year pre-opt-out, 1972 people in prison (PIP) were tested, compared to 3440 in the year following opt-out. From July 2016 to June 2017, 2706 people were tested, representing 13.5% of all prison entrants (median 16.6%, range 7.6%-40.7%). Factors correlating with testing rates were as follows: pre-admission location of the PIP (another prison or the community, OR 2.2, 95% CI 1.9-2.3, P < 0.001); whether the PIP could access health care independently of prison officers (OR 1.7, 95% CI 1.5-1.8, P < 0.001); the absence of out-reach services for HCV treatment (OR 1.3, 95% CI 1.2-1.5, P < 0.001), whether >50% of PIP reported ease of access to a nurse (OR 2.0, 95% CI 1.8-2.2, P < 0.001), and whether prison health care was supplied by private or NHS providers (OR 1.3, 95% CI 1.2-1.5, P < 0.001). Testing rates remained far below the minimum national opt-out target of 50%. Inadequacy of healthcare facilities and constraints imposed by adherence to prison regimens were cited by healthcare and management staff at all prisons. Without radical change, the prison estate may be intrinsically incapable of supporting NHSE to deliver the HCV elimination strategy.
Subject(s)
Hepatitis C/diagnosis , Prisoners , Adolescent , Dried Blood Spot Testing , Female , Hepacivirus/pathogenicity , Hepatitis C/blood , Hepatitis C/epidemiology , Humans , Male , National Health Programs/standards , National Health Programs/statistics & numerical data , Prisons , United Kingdom/epidemiology , Young AdultABSTRACT
BACKGROUND AND AIMS: Previous studies have shown low rates of diagnosis and treatment of hepatitis C virus (HCV) infection in people who inject drugs (PWID). Our aims were to test the effect of a complex intervention [Hepatitis C Awareness Through to Treatment (HepCATT)] in drug and alcohol clinics-primarily, on engagement of HCV-positive PWID with therapy and, secondarily, on testing for HCV, referral to hepatology services and start of HCV treatment. DESIGN AND SETTING: A non-randomized pilot study in three specialist addiction clinics in England comparing an intervention year (starting between September 2015 and February 2016) with a baseline year (2014), together with three control clinics. PARTICIPANTS: Analysis included all attendees at the intervention and control specialist addiction clinics identified as PWID. INTERVENTION: The intervention comprised the placement of a half-time facilitator in each clinic for 12 months with the brief to increase diagnosis of HCV infection within clients at those services and the engagement of diagnosed individuals with an appropriate care pathway. The facilitator undertook various activities, which could include training of key workers, direct interaction with clients, streamlining and support for hepatology appointments and introduction of dried blood-spot testing. MEASUREMENTS: For each clinic and period, we obtained the total number of clients and, as relevant, their status as PWID, tested for HCV, known HCV-positive, engaged with HCV therapy or treated. FINDINGS: Compared with baseline, there was strong evidence that engagement with HCV therapy in the intervention year increased (P < 0.001) more in the HepCATT centres than controls, up + 31 percentage points [95% confidence interval (CI) = 19-43] versus -12 (CI = -31 to + 6) and odds ratio (OR) = 9.99 (CI = 4.42-22.6) versus 0.35 (CI = 0.08-1.56). HepCATT centres also had greater increases in HCV testing (OR = 3.06 versus 0.78, P < 0.001), referral to hepatology (OR = 9.60 versus 0.56, P < 0.001) and treatment initiation (OR = 9.5 versus 0.74, P < 0.001). CONCLUSIONS: Introducing a half-time facilitator into drug and alcohol clinics in England increased engagement of HCV-positive people who inject drugs with hepatitis C virus care pathways, with increased uptake also of testing, referral to hepatology and initiation of treatment.
Subject(s)
Delivery of Health Care/organization & administration , Gastroenterology/statistics & numerical data , Hepatitis C, Chronic/diagnosis , Referral and Consultation/organization & administration , Substance Abuse, Intravenous/therapy , Antiviral Agents/therapeutic use , Continuity of Patient Care , England , Feasibility Studies , Hepatitis C, Chronic/epidemiology , Hepatitis C, Chronic/therapy , Humans , Nurse Specialists , Pilot Projects , Substance Abuse Treatment Centers , Substance Abuse, Intravenous/epidemiologyABSTRACT
Virus infections cause diseases of different severity ranged from mild infection e.g. common cold into life threatening diseases e.g. Human Immunodeficiency virus (HIV), Hepatitis B. Virus infections represent 44% of newly emerging infections. Although there are many efficient antiviral agents, they still have drawbacks due to accumulation at off target organs and developing of virus resistance due to virus mutation. Therefore, developing a delivery system that can selectively target drug into affected organs and avoid off target accumulation would be a highly advantageous strategy to improve antiviral therapy. Nanoparticles (NP) can be effectively targeted to the liver, and therefore it could be used for improving therapy of hepatic virus infections including hepatitis B virus and hepatitis C virus (HCV). Many studies were performed to encapsulate antiviral agents into nano-delivery system to improve their pharmacokinetics parameters to have a better therapeutic efficacy with lower side effects. However, the effect of virus infection on the uptake of NP has not yet been studied in detail. The latter is a crucial area as modulation of endocytic uptake of nanoparticles could impact on reduce potential therapeutic usefulness of antiviral agents loaded into nano-delivery system. In this study, a fluorescently-labelled polymeric nanoparticle was prepared and used to track NP uptake into Huh7.5, human hepatoma cells transfected with replicating HCV genomes, compared with non-transfected cells as a model representing hepatocyte uptake. Confocal microscopy and flow cytometry of virus transfected Huh7.5 cells unexpectedly demonstrated two-fold increase in uptake of NP compared to non-transfected cells. Therefore, virus transfection enhanced NP uptake into Huh7.5 cells and NP could be considered as a promising delivery system for targeted treatment of hepatitis viruses.
Subject(s)
Antiviral Agents/administration & dosage , Drug Delivery Systems/methods , Hepacivirus/drug effects , Hepatocytes/metabolism , Nanoparticles/chemistry , Cell Line, Tumor , HIV Infections/drug therapy , Hepacivirus/genetics , Hepatitis C/drug therapy , Hepatocytes/drug effects , Humans , Liver/cytology , Liver/drug effects , Permeability , Polymers/chemistry , TransfectionABSTRACT
Aims Ribavirin is a nucleoside analogue and remains a necessary component of both interferon-based and directly acting anti-viral regimens for the treatment of hepatitis C virus infection. The achievable concentration of ribavirin within hepatocytes is likely to be an important determinant of therapeutic outcome. In vitro expression levels of equilibrative nucleoside transporter 1 (ENT1) has been shown to be a predictor of treatment response in patients receiving nucleoside-based chemotherapeutic agents. We therefore investigated whether a similar relationship existed between ENT1 expression and ribavirin uptake in freshly isolated primary hepatocytes. Methods Primary hepatocytes were cultured on collagen-coated plates and exposed to ribavirin. Parallel samples were taken for high-performance liquid chromatography to assess ribavirin uptake and for quantitative polymerase chain reaction to evaluate ENT1 expression. Similar assays were performed on the human hepatoma cell line (Huh7). ENT1 gene sequence was analysed by cloning of polymerase chain reaction amplified complementary DNA followed by direct sequencing. Results There was a strong direct correlation between expression of ENT1 in primary hepatocytes and ribavirin uptake at 24 hr. Huh7 cells expressed ENT1 at similar levels to the majority of primary hepatocytes, but did not take up ribavirin. Sequencing revealed that ENT1 in Huh7 cells is wild type. Conclusions In this study, we clearly demonstrate that ribavirin uptake in primary human hepatocytes is variable and correlates with ENT1 expression. This variation in ENT1 expression may account for differences in response rate in patients receiving ribavirin-based anti-hepatitis C virus therapy.
Subject(s)
Equilibrative Nucleoside Transporter 1/biosynthesis , Hepatocytes/metabolism , Ribavirin/pharmacokinetics , Antimetabolites/pharmacokinetics , Base Sequence , Cell Line, Tumor , Chromatography, High Pressure Liquid/methods , Equilibrative Nucleoside Transporter 1/genetics , Equilibrative Nucleoside Transporter 1/metabolism , HumansABSTRACT
Background: Histopathologic examination alone can be inadequate for diagnosis of certain melanocytic neoplasms. Recently, a 23-gene expression signature was clinically validated as an ancillary diagnostic test to differentiate benign nevi from melanoma. The current study assessed the performance of this test in an independent cohort of melanocytic lesions against clinically proven outcomes.Methods: Archival tissue from primary cutaneous melanomas and melanocytic nevi was obtained from four independent institutions and tested with the gene signature. Cases were selected according to pre-defined clinical outcome measures. Malignant lesions were defined as stage I-III primary cutaneous melanomas that produced distant metastases (metastatic to sites other than proximal sentinel lymph node(s)) following diagnosis of the primary lesion. Melanomas that were metastatic at the time of diagnosis, all re-excisions, and lesions with <10% tumor volume were excluded. Benign lesions were defined as cutaneous melanocytic lesions with no adverse long-term events reported.Results: Of 239 submitted samples, 182 met inclusion criteria and produced a valid gene expression result. This included 99 primary cutaneous melanomas with proven distant metastases and 83 melanocytic nevi. Median time to melanoma metastasis was 18 months. Median follow-up time for nevi was 74.9 months. The gene expression score differentiated melanoma from nevi with a sensitivity of 93.8% and a specificity of 96.2%.Conclusions: The results of gene expression testing closely correlate with long-term clinical outcomes of patients with melanocytic neoplasms.Impact: Collectively, this provides strong evidence that the gene signature adds valuable adjunctive information to aid in the accurate diagnosis of melanoma. Cancer Epidemiol Biomarkers Prev; 26(7); 1107-13. ©2017 AACR.
Subject(s)
Gene Expression Profiling/methods , Gene Expression Regulation, Neoplastic , Melanoma/genetics , Nevus, Pigmented/genetics , Adult , Aged , Diagnosis, Differential , Female , Follow-Up Studies , Humans , Male , Melanocytes/metabolism , Melanoma/diagnosis , Melanoma/pathology , Middle Aged , Nevus, Pigmented/diagnosis , Nevus, Pigmented/pathology , Sensitivity and Specificity , Skin/pathology , TranscriptomeABSTRACT
Nottingham Health Science Biobank (NHSB) was established in 2011 by a 3-year "pump priming" grant from the United Kingdom National Institute of Health Research. Before biobanking operations began, NHSB commissioned a financial report on the full costs of biobanking and worked with key stakeholders and external consultants to develop a business plan with the aim of achieving financial and operational sustainability. The plan included: scanning published information, telephone interviews with commercial companies, Freedom of Information Requests, dialogue with prospective customers, and a market analysis of global trends in the use of human tissue samples in research. Our financial report provided a comprehensive and structured costing template for biobanking and confirmed the absolute requirement to ensure cost-efficient processes, careful staff utilization, and maximization of sample turnover. Together with our external consultants, we developed a business model responsive to global interest in healthcare founded on i) identification of key therapeutic areas that mapped to the strengths of the NHSB; ii) a systematic approach to identifying companies operating in these therapy areas; iii) engagement with noncommercial stakeholders to agree strategically aligned sample collection with the aim of ensuring the value of our tissue resource. By adopting this systematic approach to business modelling, the NHSB has achieved sustainability after less than 3 years of operation.
Subject(s)
Biological Specimen Banks/economics , Biological Specimen Banks/organization & administration , Biomedical Research/economics , Cost-Benefit Analysis , Humans , Models, Economic , Specimen Handling/economics , United KingdomABSTRACT
BACKGROUND: Individuals with liver disease, and especially those with Hepatitis B or C, are at an increased risk of developing hepatocellular carcinoma (HCC) which is the third most common cause of cancer-related death worldwide. Inadequate screening tests largely account for presentation of advanced tumours and high mortality rates. Early detection of HCC amongst high-risk groups is paramount in improving prognosis. This research aimed to further characterise the previously described humoral immune response raised to tumour-associated antigens (TAAs) in the serum of patients with HCC. METHODS: Serum from 96 patients with confirmed HCC, 96 healthy controls matched for age and sex, 78 patients with confirmed liver cirrhosis and 91 patients with confirmed chronic liver disease were analysed for the presence of IgG autoantibodies raised to 41 recombinant TAAs/antigen fragments by ELISA. RESULTS: Varying autoantibody specificities (97-100%) and sensitivities (0-10%) were observed to individual TAAs. A 21-antigen panel achieved a specificity of 92% and sensitivity of 45% for the detection of HCC. This same panel identified 21% of 169 high-risk controls as having elevated autoantibody levels. A reproducible panel of 10 antigens achieved a specificity of 91% and sensitivity of 41% in HCC. 15% of 152 high-risk controls gave positive results with this panel. CONCLUSIONS: This minimally invasive blood test has the potential to offer advantages over currently available tools for the identification of HCC amongst pre-disposed patients. Results are comparable to current gold standards in HCC (Ultrasonography) and to similar tests in other cancers (EarlyCDT-Lung).
Subject(s)
Autoantibodies/blood , Carcinoma, Hepatocellular/diagnosis , Early Detection of Cancer/methods , Liver Neoplasms/diagnosis , Adult , Aged , Biomarkers, Tumor/blood , Carcinoma, Hepatocellular/blood , Carcinoma, Hepatocellular/immunology , Case-Control Studies , Enzyme-Linked Immunosorbent Assay , Female , Humans , Liver Diseases/blood , Liver Diseases/complications , Liver Diseases/immunology , Liver Neoplasms/blood , Liver Neoplasms/immunology , Male , Middle AgedABSTRACT
UNLABELLED: Osteopontin (OPN) is an important component of the extracellular matrix (ECM), which promotes liver fibrosis and has been described as a biomarker for its severity. Previously, we have demonstrated that Sex-determining region Y-box 9 (SOX9) is ectopically expressed during activation of hepatic stellate cells (HSC) when it is responsible for the production of type 1 collagen, which causes scar formation in liver fibrosis. Here, we demonstrate that SOX9 regulates OPN. During normal development and in the mature liver, SOX9 and OPN are coexpressed in the biliary duct. In rodent and human models of fibrosis, both proteins were increased and colocalized to fibrotic regions in vivo and in culture-activated HSCs. SOX9 bound a conserved upstream region of the OPN gene, and abrogation of Sox9 in HSCs significantly decreased OPN production. Hedgehog (Hh) signaling has previously been shown to regulate OPN expression directly by glioblastoma (GLI) 1. Our data indicate that in models of liver fibrosis, Hh signaling more likely acts through SOX9 to modulate OPN. In contrast to Gli2 and Gli3, Gli1 is sparse in HSCs and is not increased upon activation. Furthermore, reduction of GLI2, but not GLI3, decreased the expression of both SOX9 and OPN, whereas overexpressing SOX9 or constitutively active GLI2 could rescue the antagonistic effects of cyclopamine on OPN expression. CONCLUSION: These data reinforce SOX9, downstream of Hh signaling, as a core factor mediating the expression of ECM components involved in liver fibrosis. Understanding the role and regulation of SOX9 during liver fibrosis will provide insight into its potential modulation as an antifibrotic therapy or as a means of identifying potential ECM targets, similar to OPN, as biomarkers of fibrosis.
Subject(s)
Liver Cirrhosis/diagnosis , Liver Cirrhosis/etiology , Osteopontin/physiology , SOX9 Transcription Factor/physiology , Animals , Disease Progression , Humans , Male , Osteopontin/biosynthesis , Rats , Rats, Sprague-Dawley , SOX9 Transcription Factor/biosynthesisABSTRACT
OBJECTIVES: This study assesses whether pegylated interferon and ribavirin is cost-effective compared with no antiviral treatment provided in routine clinical practice, for different patient subgroups. METHODS: The cost-effectiveness analysis (CEA) uses a Markov decision model to estimate the lifetime cost per quality-adjusted life-year (QALY) of antiviral treatment compared with no treatment. The model is populated with data on sustained virological responses, costs, and transition probabilities all taken from a large representative sample of UK cases and centers (Trent HCV database). RESULTS: The CEA found that pegylated interferon and ribavirin was cost-effective for most patient subgroups. The CEA found that for patients with genotype non-1, the intervention led to cost reductions and gains of at least 0.5 QALYs. For genotype 1 cases with mild or moderate disease, and younger cirrhotic patients (aged 40 or less), costs per QALY remained below 20,000 pound sterling ($40,000 or 29,000 euro). For genotype 1 cases with cirrhosis aged 50, the mean cost per QALY rose to over 60,000 pound sterling ($120,000 or 87,000 euro). CONCLUSIONS: The study concludes that, based on cost and effectiveness data collected from routine clinical practice, treatment with pegylated interferon and ribavirin is generally cost-effective. The study shows that there are variations according to patient subgroup and for older (aged 50 or over) genotype 1 patients with cirrhosis, antiviral treatment appears less cost-effective.
Subject(s)
Antiviral Agents/economics , Hepatitis C, Chronic/drug therapy , Interferon-alpha/economics , Polyethylene Glycols/economics , Ribavirin/economics , Adult , Antiviral Agents/therapeutic use , Cost-Benefit Analysis , Decision Trees , Drug Therapy, Combination , Female , Health Care Costs , Humans , Interferon alpha-2 , Interferon-alpha/therapeutic use , Male , Markov Chains , Middle Aged , Polyethylene Glycols/therapeutic use , Quality-Adjusted Life Years , Recombinant Proteins , Ribavirin/therapeutic useABSTRACT
BACKGROUND: Hepatitis C virus (HCV) is a major cause of liver disease worldwide. In industrialized countries, intravenous drug users (IDUs) are the main reservoir of infection. Relatively little information is available on HCV in the developing world. SOURCES OF DATA: Peer reviewed publications and presentations at major academic meetings. AREAS OF AGREEMENT: HCV-related cirrhosis and death from hepatocellular carcinoma are likely to rise dramatically in the next three decades. Urgent intervention is required both to minimize the burden of disease in those already infected and to reduce the incidence of new infections, particularly in the IDU population. AREAS OF CONTROVERSY: Current models of care and commissioning in the UK and other countries do not adequately identify or treat HCV infection in IDUs. Most strategies focus on disease prevention and do not target new infections. GROWING POINTS: New models of care are currently being developed and validated. AREAS TIMELY FOR DEVELOPING RESEARCH: The development of new models of HCV replication will transform our understanding and capacity to treat HCV infection.
Subject(s)
Hepacivirus/drug effects , Hepatitis C/etiology , Substance Abuse, Intravenous/complications , Hepacivirus/physiology , Hepatitis C/drug therapy , Humans , Virus ReplicationABSTRACT
OBJECTIVE: We analysed the Trent Hepatitis C cohort to determine standardised mortality ratios in patients infected with hepatitis C virus (HCV), and to identify risk factors and associations with all-cause and liver-related mortality. DESIGN: Cohort study. SETTING: Patients with HCV infection attending secondary care within the Trent region of England. PATIENTS: 2285 patients with hepatitis C, followed for 1 year or more. MAIN OUTCOME MEASURES: The death rate in the cohort was compared to that seen in an age- and sex-matched English population. We performed Cox regression analyses to identify factors predictive of all-cause mortality and deaths from liver disease. RESULTS: Standardised mortality ratios in the cohort were three times higher than those expected in the general population of England. The excess deaths were due to liver-related causes and those associated with a drug-using lifestyle. Significant independent predictors of all-cause mortality were age, sex, treatment (protective) and liver biopsy fibrosis. Age, treatment, liver biopsy fibrosis and mean alcohol consumption were predictors of liver-related mortality. HCV was mentioned on 23% of death certificates overall, and on 52% of those of patients dying from a liver-related cause. CONCLUSIONS: Our findings demonstrate that the death rate in patients infected with hepatitis C is three times higher than expected. Severity of disease is associated with a worse prognosis, whilst treatment improves outcome, particularly in those who respond. Use of death certificate data on HCV infection for planning purposes will result in considerable under-estimation of the HCV-related disease burden.
Subject(s)
Hepatitis C/mortality , Adult , Age Distribution , Aged , Aged, 80 and over , Alcohol Drinking/mortality , Cause of Death , England/epidemiology , Female , Hepatitis C/complications , Hepatitis C/drug therapy , Humans , Liver Cirrhosis/complications , Liver Cirrhosis/mortality , Male , Middle Aged , Prospective Studies , Sex DistributionABSTRACT
Hepatitis C virus (HCV) cell entry involves interaction between the viral envelope glycoprotein E2 and the cell surface receptor CD81. Knowledge of conserved E2 determinants important for successful binding will facilitate development of entry inhibitors designed to block this interaction. Previous studies have assigned the CD81 binding function to a number of discontinuous regions of E2. To better define specific residues involved in receptor binding, a panel of mutants of HCV envelope proteins was generated, where conserved residues within putative CD81 binding regions were sequentially mutated to alanine. Mutant proteins were tested for binding to a panel of monoclonal antibodies and CD81 and for their ability to form noncovalent heterodimers and confer infectivity in the retroviral pseudoparticle (HCVpp) assay. Detection by conformation-sensitive monoclonal antibodies indicated that the mutant proteins were correctly folded. Mutant proteins fell into three groups: those that bound CD81 and conferred HCVpp infectivity, those that abrogated both CD81 binding and HCVpp infectivity, and a final group containing mutants that were able to bind CD81 but were noninfectious in the HCVpp assay. Specific amino acids conserved across all genotypes that were critical for CD81 binding were W420, Y527, W529, G530, and D535. These data significantly increase our understanding of the CD81 receptor-E2 binding process.
Subject(s)
Antigens, CD/metabolism , Hepacivirus/pathogenicity , Receptors, Virus/metabolism , Viral Envelope Proteins/chemistry , Viral Envelope Proteins/metabolism , Amino Acid Sequence , Cell Line , Conserved Sequence , Hepacivirus/genetics , Humans , Molecular Sequence Data , Mutagenesis, Site-Directed , Mutation , Tetraspanin 28 , Viral Envelope Proteins/geneticsABSTRACT
In this study, we demonstrate the ability of a three-dimensional co-culture model to preserve some key aspects of differentiated hepatocyte function in vitro. Freshly isolated rat hepatocytes in co-culture with activated stellate cells rapidly aggregate to form well-defined viable spheroids. After 5 days in culture, the spheroids have a complex extracellular matrix support and hepatic ultrastructure including bile canaliculi, tight junctions, desmosomes and lipid storage. Co-culture spheroids have superior cytochrome P450 (CYP450) 3A and 2B function, and increased inducibility of 2B function, relative to a range of hepatocyte monoculture techniques (high-performance liquid chromatography of testosterone metabolites). Increased function in co-culture is supported by greater expression of CYP450 3A23, 1A2, and 2E1 mRNA relative to monoculture (reverse transcriptase quantitative polymerase chain reaction). Also, high hepatocyte growth factor mRNA expression in co-culture suggests a post-traumatic, or possibly regenerative, environment. A preliminary study of human hepatocytes co-cultured with rat stellate cells demonstrated prolonged function of CYP450 3A4, 2C19 and 2C9. This study shows that stellate cells facilitate spheroid formation, influence spheroid architecture, and are an effective method of preserving some aspects of hepatocyte function in the early stage of culture.
Subject(s)
Coculture Techniques/methods , Hepatocytes/cytology , Liver/cytology , Spheroids, Cellular , Animals , Cell Differentiation , Cytochrome P-450 Enzyme System/analysis , Cytochrome P-450 Enzyme System/genetics , Cytochrome P-450 Enzyme System/metabolism , Hepatocytes/enzymology , Humans , RNA, Messenger/analysis , RNA, Messenger/metabolism , RatsABSTRACT
The CD95 (Fas) molecule transmits apoptotic signals important in B-cell development and the genesis of B-cell lymphoma. We have investigated the surface and intracellular expression of CD95 in Burkitt's lymphoma (BL) cells, an important non-Hodgkin's lymphoma of B-cell origin. Group I BL cells did not express CD95 at the cell surface, but contained high levels of this receptor in the cytoplasm. In contrast, group III BL cells expressed CD95 intracellularly and at the cell surface. In group I and group III BL cells, cytoplasmic CD95 was localized to the Golgi complex, as assessed by confocal immunofluorescence microscopy and subcellular fractionation followed by immunoblotting. Trafficking through the Golgi complex is regulated by elements within the target protein and cellular sorting mechanisms. CD95 contains candidate signals for interaction with trafficking machinery. Group I BL cells can be induced to upregulate surface expression of CD95 following CD40 ligation and certain group I BL cell lines drift invitro to a group III phenotype, with consequent surface expression of CD95. Taken together, these observations show that CD95 can either be retained in the Golgi complex or exported to the cell surface, and suggest that membrane trafficking has an important and previously unrecognized role in regulating CD95 expression in B lymphocytes.
Subject(s)
Burkitt Lymphoma/metabolism , Golgi Apparatus/metabolism , fas Receptor/metabolism , Flow Cytometry , Humans , Reverse Transcriptase Polymerase Chain Reaction , Tumor Cells, Cultured , Up-RegulationABSTRACT
Hepatitis C virus (HCV) exists as a complex swarm of genetically related viruses known as a quasispecies. Recent work has shown that quasispecies complexity and evolutionary rates are associated with the outcome of acute infection. Knowledge of how the virus population evolves at different stages of chronic infection is less clear. We have studied rates of evolution of the first hypervariable region (HVR1) of the E2 envelope protein in six individuals with disparate liver disease severity. These data show that virus populations present in individuals with mild non-progressive liver disease evolve in a typical Darwinian fashion, with a consistent accumulation of non-synonymous (amino acid-changing) substitutions. By contrast, the virus population remains relatively static in individuals with severe progressive liver disease. Possible mechanisms for this disparity are discussed.