Human cytomegalovirus (CMV) is a significant infectious agent causing disease in immunocompromised HIV-infected patients, transplant recipients, and neonates. The current antiviral therapeutic strategy against CMV is limited in its utility due to the inherent toxicity and lack of bioavailability of currently available anti-CMV agents, ganciclovir (GCV), cidofovir (CDV), and foscarnet (FOS). The development of the prodrug of GCV, valganciclovir (val-GCV), has vastly improved the bioavailability profile of GCV. However, val-GCV demonstrates limited effectiveness against tissue-invasive CMV diseases as side effects involved with traditional intravenously administered GCV such as haematologic and reproductive toxicities remain. In addition, the emergence of antiviral resistant CMV mutant strains due to prolonged treatment with currently available antivirals necessitates the development of novel anti-CMV agents with reduced toxicity and improved bioavailability. In this study, select groups of novel compounds were analysed for their potential for further development as anti-CMV agents. Three groups of compounds were identified based on two screening methods which included the computer simulated screening process of compounds known as in silico screening and the traditional method of random screening. The first group of compounds (CATi) were identified by in silico screening against the CMV DNA polymerase catalytic aspartate triad, resulting in the identification of 31 compounds with the potential for inhibitory activity against CMV. The second group of compounds (PRO-i) were identified through in silico screening against the CMV protease, identifying a total of 18 lead compounds exhibiting structural complementarity with CMV protease. The third and final group of compounds (TPEX) were identified through random screening and consisted of plant extracts purified from tropical plants. All three compounds were initially screened for cytotoxicity against human fibroblasts. Plaque reduction assays were performed using compounds with acceptable levels of cytotoxicity to determine the ability of the compounds to inhibit the replication of the laboratory antiviral sensitive CMV strain, Towne. Two of the PRO-i compounds demonstrated good antiviral activity against CMV. Eleven percent (2/18) of the PRO-i compounds inhibited CMV replication, with PRO-i-43 and PRO-i??-44 displaying mean 50% inhibitory concentrations (IC50) of 4.8 ?? 1.2 ??M and 8.04 ??M, respectively. PRO-i-43 and PRO-i-44 are thus good candidates for further development as novel antiviral agents against CMV. The majority of CATi and TPEX compounds displayed significant cytotoxicity against human fibroblasts and compounds with acceptable levels of cytotoxicities did not significantly inhibit CMV replication. However, the identification of compounds with low cytotoxicities provides a good foundation for further development of novel anti-CMV agents with superior antiviral activity. In silico screening against three-dimensional viral protein models is a useful strategy for the identification of novel antiviral agents with the potential for inhibitory activity against CMV. Structural modification to produce potent derivatives of the identified anti-CMV compounds (PRO-i-43 and PRO-i-44) is a good option for the further development of novel antiviral agents against CMV. Such further examination of the identified compounds with anti-CMV activity is required to investigate their activity against not only antiviral sensitive CMV strains but also resistant CMV strains. Further investigations will yield new insights into their target, allowing further identification of compounds with potential anti-CMV activity with pharmaceutical application.

Human cytomegalovirus (HCMV) is a highly prevalent opportunistic infection and a major pathogen in immune-compromised patients. The virus exhibits a wide cell tropism and is able to lytically infect virtually any cell type, with detectable gene expression and release of new virions, but not the neutrophil. This cell is the first immune cell to engage most pathogens, engulfing and killing them before undergoing apoptosis and clearance by macrophages. However certain viruses and bacteria are able to evade host defences and use the neutrophil as a “Trojan horse” for replication and dissemination. In this context, enhanced neutrophil survival may promote infection. This work describes a profound neutrophil survival phenotype elicited by contact with live or UV-inactivated HCMV, in the absence of lytic viral gene expression. The effect does not involve signalling through candidate Toll-like receptors, but is dependent on activation of the ERK MAPK and NFκB signalling pathways, and is viral strain-dependent, restricted to clinical strains of the virus. Furthermore, HCMV triggers the secretion of a bioactive secretome that induces a similar paracrine anti-apoptotic effect in fresh neutrophils, and stimulates monocyte chemotaxis and differentiation to a phenotype that is permissive for HCMV infection. This “transferrable” effect is not due to residual virus or the presence of well-known neutrophil survival factors such as IL-6 or IL-8, but is mediated by a heat-stable protein or lipid, secreted late in culture. These results are supported by data in neutrophils isolated from patients with CMV viraemia and pneumonitis which show increased survival ex vivo, and will be further investigated using plasma membrane profiling by amino-oxybiotinylation and tandem mass tag mass spectrometry. This technique, used for the first time here in a primary cell type, allows quantitative proteomics to be performed for the first time in the neutrophil. This work demonstrates that the technique provides a comprehensive readout of all neutrophil plasma membrane proteins in a sample, with high plasma membrane purity and minimal neutrophil activation and necrosis, validated by flow cytometry. Furthermore, this has been applied to generate plasma membrane profiles for the resting, inflammatory and apoptotic neutrophil, revealing a number of neutrophil cell surface molecules not found by previous membrane proteomic methods. This technique has the potential to analyse the effect of HCMV and other pathogens on the expression profile of the neutrophil surface membrane and to examine how neutrophil signalling and function is modulated. These data shed light on the role of neutrophil apoptosis as a potential promoter of HCMV infection, and have the potential to increase our understanding of both the neutrophil’s response to pathogen invasion and to generate future approaches to combating HCMV dissemination and pathogenesis.

Orientadora: Profa. Dra. Maria Cristina Carlan da Silva / Tese (doutorado) - Universidade Federal do ABC, Programa de Pós-Graduação em Biossistemas, 2018. / A relação entre a presença do Citomegalovírus Humano (HCMV) e diversos tipos de tumores tem sido alvo de investigação por décadas, e em especial, em Glioblastoma Multiforme (GBM). O GBM é o mais maligno tumor do Sistema Nervoso Central (SNC), com baixa sobrevida mesmo após o tratamento. Nosso grupo e outros demonstraram a presença do HCMV neste tipo de tumor restrita a uma pequena quantidade de células, além disso, vários mecanismos de aumento de malignidade tumoral mediados pelo HCMV já foram demonstrados in vitro e in vivo. As principais drogas utilizadas durante o tratamento quimioterápico, Temozolamida (TMZ) e Carmustina (BCNU), levam a adição de adutos no DNA, criando erros durante a replicação celular. Estudos demonstram que o HCMV pode modular vias de reparo de DNA em fibroblastos, entretanto, o possível efeito durante a quimioterapia não é conhecido. Com isto, neste trabalho avaliou-se a infecção viral de linhagens celulares de GBM bem como a resposta das mesmas ao tratamento com TMZ e BCNU. Demonstrou-se que linhagens de GBM U87MG, A172, U251MG e TP365MG são suscetíveis a infecção por HCMV, mas não igualmente permissíveis as linhagens virais laboratoriais (AD169) e clínica (TB40), provavelmente refletindo a infectividade do vírus nos tumores. Observou-se também uma diminuição na viabilidade celular nas linhagens TP365MG e U251MG infectadas com HCMV, de maneira dependente da multiplicidade de infecção (MOI). Na presença concomitante de drogas e vírus também ocorre a diminuição de viabilidade MOI dependente, especificamente em TP365MG tratada com BCNU. Em suma, os resultados indicam que a permissibilidade do HCMV em células de GBM é determinada por fatores celulares/hospedeiro e não por fatores virais. Por fim, o vírus também não aumenta a resistência ao tratamento por TMZ e BCNU em linhagens U251MG e TP365MG, entretanto, devido a heterogeneidade tumoral mais estudos são necessários em outros tipos celulares, especialmente em células tronco tumorais, levando a um melhor entendimento do possível efeito do vírus durante o tratamento quimioterápico / The relationship between the Human Cytomegalovirus (HCMV) and different types of tumors has been investigated for many decades, especially in Glioblastoma Multiforme (GBM). GBM is the most malignant tumor of the Nervous Central System (SNC), with a low overall survival even after treatment. We and others demonstrated the presence of HCMV in this type of tumor, restricted to a small number of cells, and various studies showed that the virus can increase cell malignancy both in vitro and in vivo. The chemotherapeutic agents Temozolomide (TMZ) and Carmustine (BCNU) used in GBM treatment lead to insertion of adducts in the DNA, creating errors during replication. It is well known that HCMV can modulate DNA repair pathways in fibroblasts, however, the possible effect of the virus during chemotherapy is not known. In this work we analyzed viral infection in GBM cell lines and their response to the TMZ and BCNU. We demonstrated that A172, U251MG and TP365MG GBM cell lines are susceptible to HCMV infection, but not equally permissive to both laboratory (AD169) and clinical strains (TB40), likely reflecting infection in the tumor. Additionally, we show a decrease in cell viability in TP365MG and U251MG infected with HCMV, in a MOI dependent manner. In infected and treated with chemotherapeutic drugs cells, there is also a reduction in cell viability MOI dependent in TP365MG treated with BCNU. Overall our results indicate that HCMV permissiveness in GBM cells is determined by host/cellular rather than viral factors and that the virus does not increase cell resistance to chemotherapeutic drugs in U251MG and TP365MG. Due to the tumor heterogeneity, more studies need to be performed in other tumor cells, especially in cancer stem cells, to lead to a better understanding of the possible effect of the virus during chemotherapy.

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AIDS-related human cytomegalovirus (HCMV) retinitis remains the leading cause of blindness among untreated HIV/AIDS patients worldwide. Understanding the pathogenesis of this disease is essential for developing new, safe, and effective treatments for its prevention or management, yet much remains unknown about the virologic and immunologic mechanisms contributing to its pathology. To study such mechanisms, we use a well-established, reproducible, and clinically relevant animal model with retrovirus-induced murine acquired immunodeficiency syndrome (MAIDS) that mimics in mice the symptoms and progression of AIDS in humans. Over 8 to 12 weeks, MAIDS mice become susceptible to experimental murine cytomegalovirus (MCMV) retinitis. We have found in this model that MCMV infection significantly stimulates ocular suppressor of cytokine signaling (SOCS)1 and SOCS3, host proteins which dampen immune-related signaling by cytokines, including antiviral interferons. Herein we investigated virologic and/or immunologic mechanisms involved in this stimulation and how virally-modulated SOCS1 and/or SOCS3 proteins may contribute to MCMV infection or experimental MAIDS-related MCMV retinitis. Through pursuit of two specific aims, we tested the central hypothesis that MCMV stimulates and employs SOCS1 and/or SOCS3 to induce the onset and development of MCMV retinal disease. MCMV-related SOCS1 and SOCS3 stimulation in vivo occurred with intraocular infection, was dependent on method and stage of immune suppression and severity of ocular pathology, was associated with stimulation of SOCS-inducing cytokines, and SOCS1 and SOCS3 were differentially sensitive to antiviral treatment. In vitro studies further demonstrated that SOCS1 and SOCS3 stimulation during MCMV infection occurred with expected immediate early kinetics, required viral gene expression in cell-type-dependent and virus origin-dependent patterns of expression, and displayed differential sensitivity to antiviral treatment. These data suggest that SOCS1 and SOCS3 are stimulated by divergent virologic, immunologic, and/or pathologic mechanisms during MCMV infection, and that they contribute to the pathogenesis of retinal disease, revealing new insights into the pathophysiology of AIDS-related HCMV retinitis.

In patients after allogeneic haematopoietic stem cell transplantation (HSCT) is a human cytomegalovirus (CMV) one of the most important viral pathogens. Its detailed characteristic could provide information about the impact of each CMV genotype on overall survival of the patient, and some serious complications, such as graft versus host disease (GvHD). This thesis deals with retrospective genetic analysis of samples from 1877 patients transplanted at the Clinic of Pediatric Hematology and Oncology, University Hospital Motol and the Institute of Hematology and Blood Transfusion since 2002. DNA from biological samples (especially whole blood) was isolated kit Qiagen DNA Blood Mini or Qiagen DNA Mini and samples were prospectively detected presence of CMV DNA. Samples were subsequently stored at -20 řC. Genotyping was performed using real-time PCR technologies to the genes of 2 structural proteins glycoprotein B, glycoprotein H and using sequence specific primers and probes. In 1343 samples (71.6%) from 390 patients there was only one strain of CMV; in 256 (13.6%) samples from 113 patients have detected mixed infection caused by two or more strains of CMV. The most common genotype demonstrated in "single" infection was in pediatric and adult patients gB1/gH2 detected in 118 (28.4%) patients. Most...

Viruses are obligate intracellular pathogens. Therefore, their successful replication, at every stage from attachment to assembly and egress, is dependent on host cell functions. The host cell in turn engages mechanisms to counteract virus replication. As a result, viruses have evolved mechanisms to evade these counteracting measures as well as ways to reshape the cellular environment into one that’s favourable for successful replication. Systematic studies offer a platform for unravelling virus-cell interactions and in particular can address three important aspects 1) increase our understanding of basic biology of the virus, 2) identify and characterise novel cellular functions 3) provide important leads for novel targets for antiviral therapy. In this study, I investigated two aspects of virus host interaction; the role of microRNAs (miRNAs) in virus infection and the role of interferon inducible genes in virus infection. Human cytomegalovirus (HCMV) is a β herpes virus that infects humans. HCMV maintains a persistent lifelong infection in the host involving a cycle of latency and reactivation. Infection of healthy individuals with HCMV results in relatively minor symptoms. In contrast, infection of individuals with a compromised immune system, as in the case of organ transplant recipients and AIDS patients, can cause significant morbidity and mortality. In common with other herpes viruses, HCMV expresses multiple small regulatory RNAs called miRNAs. HCMV encodes at least 14 miRNAs. Identifying the targets of these miRNAs will help us understand their functional importance during infection. Recently, a biochemical technique called Cross-Linking, Ligation and Sequencing of Hybrids (CLASH), was developed by Tollervey and colleagues, representing the most advanced systematic technique for the identification of miRNA targets. We adapted this approach to identify high confidence miRNA targets during HCMV infection. However, the protocol was sub-optimal and presented us with technical challenges. Although high quality data sets were not generated, the work was crucial for the establishment of the system which is now generating promising data. Virus-cell interactions can also be elucidated by probing for host factors that are important for virus replication. Type I interferon is a highly effective inhibitor of HCMV replication. Treatment of cells with interferon results in up regulation of multiple effectors known as interferon stimulated genes (ISGs). How these genes block HCMV replication is poorly understood. A library of more than 380 ISG expressing lentiviruses was screened to determine the effects of individual ISGs on HCMV replication. The screen was performed in primary human fibroblast cells and a glioblastoma cell line called U373s. Multiple inhibitory ISGs were identified including well characterised ISGs such as cGAS, STAT2, NOD2, DDX60 and HPSE as well as novel candidates TXNIP, ELF1, FAM46C, MT1H and CHMP5. Five ISGs were identified as HCMV replication enhancers including previously published ISGs BST2 and IFITM1 and novel enhancers ODC1, BCL3 and IL28RA. siRNA screens against top hits demonstrated that STAT2, CPT1A and cGAS are dominant inhibitory factors during HCMV infection and knockdown of these genes can partially rescue HCMV replication following interferon treatment. Finally, using a corresponding rhesus ISG library we show that rhesus SAMHD1 effectively inhibits HCMV replication while human SAMHD1 has no effect, suggesting that HCMV expresses a species-specific inhibitor of SAMHD1. This study defines interferon stimulated pathways important for HCMV replication and identifies multiple novel host factors that both restrict and enhance HCMV replication. These studies demonstrate the effectiveness of using systematic approaches for the identification of novel host virus interactions.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.

Orientador: Sandra Cecilia Botelho Costa / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-14T05:42:16Z (GMT). No. of bitstreams: 1 Peres_RenataMariaBorges.pdf: 1155626 bytes, checksum: 762e48191487fb6a14f74846243c214b (MD5) Previous issue date: 2009 / Resumo: O citomegalovírus humano (HCMV) é um vírus cosmopolita pertencente à família Herpesviridae, subfamília Betaherpesvirinae. É amplamente disseminado na população, com soroprevalência entre 40 e 100%. Sua transmissão se dá através do contato direto com secreções contendo o vírus como: sêmen, secreção cervical, urina, saliva, leite materno, hemoderivados e também através de transplante de órgãos e tecidos. Durante a infecção primária o HCMV apresenta intensa replicação e em seguida estabelece um estágio de latência no hospedeiro. Periódicas reativações ocorrem em situações de estresse, imunossupressão, doenças auto-imunes e uso de quimioterápicos. O impacto desta infecção em receptores de Transplante de Células Tronco Hematopoéticas (TCTH) é grande podendo causar pneumonia intersticial, doença no trato gastrointestinal, hepatite, mielossupressão, retinite, nefrite, encefalite, atraso da pega medular, doença do enxerto contra hospedeiro, infecções por outros organismos oportunistas, aceleração da perda do enxerto e óbito. Por este motivo, é de suma importância o uso de técnicas laboratoriais, suficientemente sensíveis e específicas, capazes de fazer o diagnóstico precoce da infecção ativa pelo HCMV e estudos mais aprofundados sobre a real relação e correlação clínica que estas técnicas apresentam a fim de prevenir o aparecimento da doença pelo HCMV e demais complicações associadas ao HCMV. Neste estudo foram monitorizados semanalmente, 30 pacientes submetidos a TCTH do tipo alogênico desde o dia do transplante até o dia 150 pós-transplante pelas técnicas de antigenemia, Nested-PCR e Real-time PCR. O tratamento precoce com medicamento antiviral foi iniciado a partir dos seguintes resultados: = 1 célula pp65 positiva/3x105 leucócitos e/ou 2 ou mais Nested-PCR positivas consecutivas. O cut-off da Real-time PCR para a infecção ativa pelo HCMV foi padronizado neste estudo, sendo de 418,39 cópias virais/104 leucócitos periféricos. Vinte e sete pacientes (90%) apresentaram infecção ativa pelo HCMV, com maior incidência durante o segundo mês pós-TCTH. Destes 27 pacientes, 21 (77,78%) foram submetidos ao tratamento precoce com Ganciclovir, 18 (66,67%) apresentaram infecções oportunistas, 11 (40,74%) tiveram DECH aguda, 9 pacientes (33,33%) tiveram infecção ativa recorrente pelo HCMV, 5 (18,52%) tiveram rejeição crônica do enxerto, 2 (7,4%) desenvolveram doença pelo HCMV e 11 (40,47%) evoluíram a óbito, sendo 1 (3,7%) por doença por HCMV associado a DECH aguda e infecção bacteriana. O teste mais precoce para o diagnóstico da infecção ativa pelo HCMV foi a Nested-PCR com mediana de 33 dias pós-TCTH, seguido pela Real-time PCR e antigenemia, ambas com mediana de 40 dias pós-TCTH. A Real-time PCR foi o teste mais sensível (S=92,3%) e que apresentou melhor valor preditivo negativo (VPN=85,71%) para o diagnóstico da infecção ativa pelo HCMV. Já a antigenemia foi o teste mais específico (E=77,77%) e que apresentou melhor valor preditivo positivo (VPP=84,61%) para este diagnóstico. Os testes utilizados no estudo foram eficazes no monitoramento da infecção ativa pelo HCMV, pois somente 2 (7,4%) dos 27 pacientes que apresentaram infecção ativa pelo HCMV desenvolveram doença por HCMV. / Abstract: Human cytomegalovirus (HCMV) is a member of the Herpesviridae family and Betaherpesvirinae subfamily. HCMV is distributed worldwide, with prevalence of HCMV-positive antibodies of 40% to 100%. Transmission occurs during close personal contact with secretions of infected persons such as: semen, cervical secretions, urine, saliva, breast milk, blood products and transplanted organs and hematopoietic stem cell. During primary infection occurs intense replication followed by latent infection in host. Periodic reactivations occur in stress situations, immunosuppression, autoimmune diseases and use of chemotherapy. The impact of HCMV infection on recipients HSCT is large and can cause pneumonitis, gastrointestinal diseases, hepatitis, marrowsuppression, retinitis, nephritis, encephalitis, delay of bone marrow engraftment, severe acute graft-versus host disease (GVHD), opportunistic infections, chronic rejection and death. For this reason it is extremely important the use of sensitive and specific methods for early diagnostic of active HCMV infection and deeper studies about the real clinical relation and correlation these techniques show in order to prevent the disease through HCMV and further complications connected to HCMV. In this study 30 patients recipients of allogenic HSCT were monitored at weekly intervals from D+0 to D+150 post-transplant by antigenemia, Nested-PCR and Real-time PCR. Antiviral preemptive therapy was initiated upon a result = 1 positive pp65 cell/3x105 of PML and/or two or more consecutive positive Nested-PCR. The optimal cut-off value by Real-time PCR for active HCMV infection was 418,39 copies/104 of PBL. Twenty seven (90%) patients had active HCMV infection, with the highest incidence occurring during the second month after HSCT. Twenty one (77,78%) of the 27 patients who had active HCMV infection received preemptive antiviral therapy with Ganciclovir, 18 (66,67%) had opportunist infection, 11 (40,74%) had acute graft-versus host disease (GVHD), 9 (33,33%) had recurrence of HCMV infection, 5 (18,51%) had chronic rejection, 2 (7,4%) developed HCMV disease and 11 (40,47%) died, one (3,7%) by HCMV disease associated with GVHD and bacterial infection. The most precocious test for diagnostic of active HCMV was Nested-PCR after a median of 33 days after HSCT followed by Real-time PCR and antigenemia, both with a median of 40 days after HSCT. Real-time PCR was the most sensitive (Sensitive=92,3%) and with the best predictive negative value (PNV=85,71%) for diagnostic of active HCMV infection. Antigenemia was the most specific (Specific=77,77%) and with the best predictive positive value (PPV=84,61%) for this diagnostic. The three assays utilized in this study were effective in active HCMV infection surveillance because only 2 (7,4%) of 27 patients that had active HCMV infection had HCMV disease. / Universidade Estadual de Campi / Ciencias Basicas / Mestre em Clinica Medica