Introdução: A microcefalia é um sinal clínico associado à heterogeneidade etiológica. As principais causas de microcefalia são as infecções congênitas e as anomalias congênitas. Em 2015, após o surto do zika vírus (ZIKV) e o aumento de casos de microcefalia, o Ministério da Saúde (MS) instituiu notificação compulsória para os recém-nascidos (RN) com microcefalia e/ou alterações do Sistema Nervoso Central (SNC). No Brasil, a distribuição geográfica do ZIKV ocorreu de maneira diferenciada nas regiões norte e sul, sendo que no extremo sul do país houve um menor número de infecções por esse vírus. Assim, o estado do Rio Grande do Sul (RS) tornou-se um local importante para a avaliação sistemática das causas de microcefalia neste país, independente da presença de transmissão continuada do ZIKV. Objetivos: Avaliar e descrever as causas de microcefalia dos RN notificados por microcefalia e/ou alterações do SNC no RS. Métodos: Estudo descritivo dos 162 RN com microcefalia notificada no período de dezembro de 2015 a dezembro de 2016. Destes, 99 casos foram avaliados de forma retrospectiva com base em revisão de banco de dados, e 63 casos foram avaliados de forma prospectiva em ambulatório específico do HCPA-Brasil. As etapas propostas para a avaliação (ou informações coletadas dos bancos de dados) foram: 1) histórico da gestante; 2) exame físico do RN; 3) exames para pesquisa de infecção congênita – toxoplasmose, rubéola, ZIKV e CMV (reação de cadeia da polimerase - PCR ou sorológicos); 4) exames de imagem do SNC; 5) avaliação genética (para os casos com história familiar ou suspeita de alteração genética). As crianças foram avaliadas do nascimento até conclusão diagnóstica, seguimento perdido ou término do estudo. O período de avaliação das crianças não foi superior a quatro meses. Resultados: Noventa e cinco casos (58,6%) apresentavam microcefalia grave, resultando em uma prevalência desta complicação ao nascimento de 6.5/10.000 RN. A causa foi definida em 73 dos 162 casos. Destes eram infecções congênitas 31 casos (19.3%), síndromes genéticas 19 casos (11.7%), e malformação isolada do sistema nervoso central 20 casos (12,4%). E a causa não foi identificada em 89 (54,9%). Dos 31 casos com infecções congênitas, três (9.7%) foram diagnosticados com ZIKV, seis (19.3%) com citomegalovírus, oito (25,8%) com toxoplasmose, e 14 (45.2%) com sífilis congênita. Nenhum caso de rubeola congênita foi diagnosticado e a imunidade adquirida para rubeola das mães dos RN notificados foi de 91.6%. Destes casos 14 (45.1%) apresentaram baixo peso ao nascer e 21 (66.7%) eram pequenos para idade gestacional. A microcefalia grave foi identificada em 12 (38.7%) e 6 59.2% dos casos apresentaram alterações cerebrais, o que reforça a gravidade da ação das doenças infecciosas. Conclusão: Este é o primeiro estudo a avaliar os casos de microcefalia e/ou alterações do SNC durante o surto de ZIKV no RS. A prevalência de casos de ZIKV no RS foi inferior a estados do Nordeste do Brasil. A maioria dos casos de infecção congênita apresentaram lesões neurológicas graves, principalmente os casos de ZIKV, o que pode ocasionar atraso no desenvolvimento neurológico e sequelas nestas crianças ao longo da primeira infância. No entanto, salientamos a importância das demais infecções congênitas e causas desconhecidas associadas à microcefalia no RS, independente da presença de ZIKV. / Introduction: Microcephaly is a clinical sign associated with etiological heterogeneity. The main causes of microcephaly are congenital infections and congenital anomalies. The Ministry of Health (MOH) has instituted compulsory notification for newborns with microcephaly and / or Central Nervous System (CNS) disorders in 2015, following the zika virus (ZIKV) outbreak and the increase in cases of microcephaly. In Brazil, the geographical distribution of ZIKV occurred in a differentiated way in the northern and southern regions, and in the southernmost part of the country there were fewer infections due to this virus. Thus, the state of Rio Grande do Sul (RS) has become an important site for the systematic evaluation of the causes of microcephaly in this country, regardless of the presence of continuous transmission of ZIKV. Objectives: To evaluate and describe the causes of microcephaly of newborns notified by microcephaly and / or CNS changes in RS. Methods: Descriptive study of the 162 newborns with microcephaly reported from December 2015 to December 2016. Of these, 99 cases were retrospectively evaluated based on a database review, and 63 cases were evaluated prospectively in an outpatient clinic specific to HCPA-Brazil. The proposed steps for the evaluation (or information collected from the databases) were: 1) history of the pregnant woman; 2) physical examination of the newborn; 3) screening tests for congenital infection - toxoplasmosis, rubella, ZIKV and CMV (polymerase chain reaction - PCR or serological); 4) imaging studies of the CNS; 5) genetic evaluation (for cases with family history or suspected genetic alteration). The children were evaluated from birth to completion of diagnosis, missed follow-up or termination of the study. The evaluation of them was not more than four months. Results: Ninety-five cases (58.6%) presented severe microcephaly, resulting in a prevalence of this complication at birth of 6.5 / 10,000 newborn. A definite cause was established in 73 of the 162 causes. The leading etiology was congenital infections in 31 cases (19.3%), genetic syndromes in 19 cases (11.7%), and isolated central nervous system malformation in 20 cases (12.4%). Of the 31 cases with congenital infections, three (9.7%) were diagnosed with ZIKV, six (19.3%) with cytomegalovirus, eight (25.8%) with toxoplasmosis, and 14 (45.2%) with congenital syphilis. No case of congenital rubella was diagnosed and the acquired immunity to rubella from the mothers of the newborns was 91.6%. Of these, 14 (45.1%) had low birth 8 weight and 21 (66.7%) were small for gestational age. Severe microcephaly was identified in 12 (38.7%) and 59.2% of the cases presented cerebral alterations, which reinforces the severity of the action of infectious diseases. Conclusion: This is the first study to assess the cases of microcephaly and / or CNS changes during the outbreak of ZIKV in RS. The prevalence of ZIKV cases in RS was lower than in the northeastern states of Brazil. Most cases of congenital infection have severe neurological lesions, especially cases of ZIKV, which can cause delay in neurological development and detectable sequelae in these children throughout their first infancy. However, we emphasize the importance of other congenital infections and unknown causes associated with microcephaly in RS, regardless of the presence of ZIKV.

O Zika vírus (ZIKV) pertence à família flaviviridae que inclui espécies transmitidas principalmente por mosquitos Aedes sp. No Brasil, casos de microcefalia fetal foram associados à infecção congênita por ZIKV. Vários mecanismos de imunorregulação operantes durante a gestação como a inflamação gerada e resposta antiviral são vitais para o entendimento da infecção congênita do ZIKV. Desta forma, é proposto avaliar se a inflamação via ativação do receptor Toll-like 4 (TLR4-LPS) em vilos placentários humanos e em modelo murino interfere na infecção por ZIKV. Para isso, explantes de vilos placentários humanos de 3o trimestre foram ativados com LPS e posteriormente infectados com ZIKV. Nossos achados mostram que a ativação com LPS é capaz de aumentar a replicação de ZIKV em vilos placentários e de elevar a atividade enzimática da lactato desidrogenase, indicativo de ativação celular. A replicação viral foi inibida com o tratamento dos explantes com um antioxidante, Naringenina, mostrando potencial terapêutico. A ativação placentária com LPS inibiu a via IRF-3, diminuindo a atividade antiviral e aumentando a clivagem proteica do componente da via de autofagia LC3, sendo que estes mecanismos podem estar relacionados com o aumento da replicação viral. Em paralelo, foi detectado aumento da produção de citocinas inflamatórias e hiperplasia das células de Hofbauer nos explantes inflamados e infectados, indicando que estes macrófagos fetais podem ser um nicho de replicação viral. Em modelo murino, evidenciamos que a inoculação intravaginal de LPS em fêmeas prenhas previamente à infecção com ZIKV é capaz de promover o aumento de carga viral no cérebro das mães e da prole, com agravamento do quadro de microcefalia nos fetos. Em conjunto, os dados mostram que em modelo de explante placentário humano e, in vivo , em camundongos, a inflamação é fator predisponente da replicação do ZIKV. As estratégias imunomoduladoras mostram potencial terapêutico, atenuando a resposta inflamatória e a diminuição da replicação viral. / The Zika virus (ZIKV) belongs to the flaviviridae family that includes species transmitted mainly by mosquitoes Aedes sp. In Brazil, cases of fetal microcephaly were associated with ZIKV congenital infection. Several mechanisms of immunoregulation operative during gestation as the inflammation generated and antiviral response are vital for the understanding of congenital ZIKV infection. Thus, it is proposed to evaluate whether inflammation via Toll-like receptor 4 (TLR4-LPS) activation in human and murine placental villi interferes with ZIKV infection. For this, human placental explants of 3rd trimester were activated with LPS and later infected with ZIKV. Our findings show that LPS activation is capable of increasing ZIKV replication in placental villi and elevating the enzymatic activity of lactate dehydrogenase, indicative of cellular activation. Viral replication was inhibited with the treatment of explants with an antioxidant, Naringenin, showing therapeutic potential. LPS placental activation inhibited the IRF-3 pathway, decreasing antiviral activity and increasing protein cleavage of the autophagy pathway component LC3, and these mechanisms may be related to increased viral replication. In parallel, increased production of inflammatory cytokines and Hofbauer cell hyperplasia were detected in inflamed and infected explants, indicating that these fetal macrophages may be a niche for viral replication. In the murine model, we demonstrated that the intravaginal inoculation of LPS in pregnant females prior to infection with ZIKV is able to promote the increase of viral load in the brains of mothers and offspring, with worsening of the microcephaly in fetuses. Together, the data show that in the model of human placental explant and, in vivo, in mice, inflammation is a predisposing factor of ZIKV replication. Immunomodulatory strategies show therapeutic potential, attenuating the inflammatory response and decreasing viral replication.

Introdução: A microcefalia é um sinal clínico associado à heterogeneidade etiológica. As principais causas de microcefalia são as infecções congênitas e as anomalias congênitas. Em 2015, após o surto do zika vírus (ZIKV) e o aumento de casos de microcefalia, o Ministério da Saúde (MS) instituiu notificação compulsória para os recém-nascidos (RN) com microcefalia e/ou alterações do Sistema Nervoso Central (SNC). No Brasil, a distribuição geográfica do ZIKV ocorreu de maneira diferenciada nas regiões norte e sul, sendo que no extremo sul do país houve um menor número de infecções por esse vírus. Assim, o estado do Rio Grande do Sul (RS) tornou-se um local importante para a avaliação sistemática das causas de microcefalia neste país, independente da presença de transmissão continuada do ZIKV. Objetivos: Avaliar e descrever as causas de microcefalia dos RN notificados por microcefalia e/ou alterações do SNC no RS. Métodos: Estudo descritivo dos 162 RN com microcefalia notificada no período de dezembro de 2015 a dezembro de 2016. Destes, 99 casos foram avaliados de forma retrospectiva com base em revisão de banco de dados, e 63 casos foram avaliados de forma prospectiva em ambulatório específico do HCPA-Brasil. As etapas propostas para a avaliação (ou informações coletadas dos bancos de dados) foram: 1) histórico da gestante; 2) exame físico do RN; 3) exames para pesquisa de infecção congênita – toxoplasmose, rubéola, ZIKV e CMV (reação de cadeia da polimerase - PCR ou sorológicos); 4) exames de imagem do SNC; 5) avaliação genética (para os casos com história familiar ou suspeita de alteração genética). As crianças foram avaliadas do nascimento até conclusão diagnóstica, seguimento perdido ou término do estudo. O período de avaliação das crianças não foi superior a quatro meses. Resultados: Noventa e cinco casos (58,6%) apresentavam microcefalia grave, resultando em uma prevalência desta complicação ao nascimento de 6.5/10.000 RN. A causa foi definida em 73 dos 162 casos. Destes eram infecções congênitas 31 casos (19.3%), síndromes genéticas 19 casos (11.7%), e malformação isolada do sistema nervoso central 20 casos (12,4%). E a causa não foi identificada em 89 (54,9%). Dos 31 casos com infecções congênitas, três (9.7%) foram diagnosticados com ZIKV, seis (19.3%) com citomegalovírus, oito (25,8%) com toxoplasmose, e 14 (45.2%) com sífilis congênita. Nenhum caso de rubeola congênita foi diagnosticado e a imunidade adquirida para rubeola das mães dos RN notificados foi de 91.6%. Destes casos 14 (45.1%) apresentaram baixo peso ao nascer e 21 (66.7%) eram pequenos para idade gestacional. A microcefalia grave foi identificada em 12 (38.7%) e 6 59.2% dos casos apresentaram alterações cerebrais, o que reforça a gravidade da ação das doenças infecciosas. Conclusão: Este é o primeiro estudo a avaliar os casos de microcefalia e/ou alterações do SNC durante o surto de ZIKV no RS. A prevalência de casos de ZIKV no RS foi inferior a estados do Nordeste do Brasil. A maioria dos casos de infecção congênita apresentaram lesões neurológicas graves, principalmente os casos de ZIKV, o que pode ocasionar atraso no desenvolvimento neurológico e sequelas nestas crianças ao longo da primeira infância. No entanto, salientamos a importância das demais infecções congênitas e causas desconhecidas associadas à microcefalia no RS, independente da presença de ZIKV. / Introduction: Microcephaly is a clinical sign associated with etiological heterogeneity. The main causes of microcephaly are congenital infections and congenital anomalies. The Ministry of Health (MOH) has instituted compulsory notification for newborns with microcephaly and / or Central Nervous System (CNS) disorders in 2015, following the zika virus (ZIKV) outbreak and the increase in cases of microcephaly. In Brazil, the geographical distribution of ZIKV occurred in a differentiated way in the northern and southern regions, and in the southernmost part of the country there were fewer infections due to this virus. Thus, the state of Rio Grande do Sul (RS) has become an important site for the systematic evaluation of the causes of microcephaly in this country, regardless of the presence of continuous transmission of ZIKV. Objectives: To evaluate and describe the causes of microcephaly of newborns notified by microcephaly and / or CNS changes in RS. Methods: Descriptive study of the 162 newborns with microcephaly reported from December 2015 to December 2016. Of these, 99 cases were retrospectively evaluated based on a database review, and 63 cases were evaluated prospectively in an outpatient clinic specific to HCPA-Brazil. The proposed steps for the evaluation (or information collected from the databases) were: 1) history of the pregnant woman; 2) physical examination of the newborn; 3) screening tests for congenital infection - toxoplasmosis, rubella, ZIKV and CMV (polymerase chain reaction - PCR or serological); 4) imaging studies of the CNS; 5) genetic evaluation (for cases with family history or suspected genetic alteration). The children were evaluated from birth to completion of diagnosis, missed follow-up or termination of the study. The evaluation of them was not more than four months. Results: Ninety-five cases (58.6%) presented severe microcephaly, resulting in a prevalence of this complication at birth of 6.5 / 10,000 newborn. A definite cause was established in 73 of the 162 causes. The leading etiology was congenital infections in 31 cases (19.3%), genetic syndromes in 19 cases (11.7%), and isolated central nervous system malformation in 20 cases (12.4%). Of the 31 cases with congenital infections, three (9.7%) were diagnosed with ZIKV, six (19.3%) with cytomegalovirus, eight (25.8%) with toxoplasmosis, and 14 (45.2%) with congenital syphilis. No case of congenital rubella was diagnosed and the acquired immunity to rubella from the mothers of the newborns was 91.6%. Of these, 14 (45.1%) had low birth 8 weight and 21 (66.7%) were small for gestational age. Severe microcephaly was identified in 12 (38.7%) and 59.2% of the cases presented cerebral alterations, which reinforces the severity of the action of infectious diseases. Conclusion: This is the first study to assess the cases of microcephaly and / or CNS changes during the outbreak of ZIKV in RS. The prevalence of ZIKV cases in RS was lower than in the northeastern states of Brazil. Most cases of congenital infection have severe neurological lesions, especially cases of ZIKV, which can cause delay in neurological development and detectable sequelae in these children throughout their first infancy. However, we emphasize the importance of other congenital infections and unknown causes associated with microcephaly in RS, regardless of the presence of ZIKV.

Au cours des récentes épidémies, l’infection par le virus Zika (ZIKV) est à l’origine de microcéphalies chez le fœtus, d’avortements spontanés et du syndrome de Guillain–Barré chez l’adulte. L’infection par ZIKV représente donc un problème de santé publique. Il est nécessaire de comprendre la biologie de ce virus et quelles sont les réponses cellulaires impliquées. Dans les cellules infectées, les virus sont détectés par des récepteurs de la réponse immunitaire innée, tels que les Toll-like receptors (TLR). Cette reconnaissance conduit à la production de molécules antivirales, tel que l’interféron (IFN) de type I et III. De récents travaux montrent que l’activation de la voie TLR3 contribuerait au contrôle de la propagation de ZIKV et sa pathogénèse. Nous avons mis en place une approche pour cartographier les interactions génétiques entre le génome viral et différents régulateurs et effecteurs de cette réponse antivirale, incluant les étapes de reconnaissance du virus par TLR3. Cette approche est basée sur une combinaison de biologie moléculaire et d’évolution expérimentale qui repose sur le taux élevé de mutation de ZIKV et sa rapide faculté d’adaptation. J’ai pu mettre en avant l’apparition d’un phénotype de ZIKV face aux défenses antivirales de lignées cellulaires humaines qui se caractérise par une résistance à l’activation de la voie TLR3 et une meilleure propagation du virus après 5 passages. J’ai été capable d’observer que la population virale adaptée présente une perte d’activation des réponses antivirales (i.e. ISG15, MxA) 3h post-infection. La mise au point et la validation de l’approche CirSeq permet une analyse de précision des données de séquençage haut-débit, et permettra ainsi de prédire l’évolution de mécanismes d’échappement viral. / Zika virus (ZIKV) infection causes neurological diseases and birth defects representing an important threat for human health. Recent studies demonstrated that interferon (IFN) response is pivotal for the control of ZIKV spread, its in utero transmission and protects against ZIKV-induced neurological diseases. It is necessary to understand the biology of this virus and what are the cellular responses involved. In infected cells, viruses are detected by receptors of the innate immune response, such as Toll-like receptors (TLRs). This recognition leads to the production of antiviral molecules, such as type I and III interferon (IFN). Recent work shows that activation of the TLR3 pathway contributes to controlling the spread of ZIKV and its pathogenesis. We have implemented an approach to map the interactions between the viral genome and different regulators and effectors of this antiviral response, including the TLR3 virus recognition steps. This approach is based on a combination of molecular biology and experimental evolution based on the high mutation rate of ZIKV and its rapid adaptation. I was able to highlight the appearance of a phenotype of ZIKV against the antiviral defenses of human cell lines that triggered resistance to activation of the TLR3 pathway and a better spread of the virus after 5 iterative passages. I was able to observe that the adapted viral population exhibited a loss of activation of antiviral responses (i.e. ISG15, MxA) 3h after infection. The implementation and validation of the CirSeq approach allows an analysis of the accuracy of high throughput sequencing data, as well as predicting the evolution of viral escape mechanisms.

Introdução: A microcefalia é um sinal clínico associado à heterogeneidade etiológica. As principais causas de microcefalia são as infecções congênitas e as anomalias congênitas. Em 2015, após o surto do zika vírus (ZIKV) e o aumento de casos de microcefalia, o Ministério da Saúde (MS) instituiu notificação compulsória para os recém-nascidos (RN) com microcefalia e/ou alterações do Sistema Nervoso Central (SNC). No Brasil, a distribuição geográfica do ZIKV ocorreu de maneira diferenciada nas regiões norte e sul, sendo que no extremo sul do país houve um menor número de infecções por esse vírus. Assim, o estado do Rio Grande do Sul (RS) tornou-se um local importante para a avaliação sistemática das causas de microcefalia neste país, independente da presença de transmissão continuada do ZIKV. Objetivos: Avaliar e descrever as causas de microcefalia dos RN notificados por microcefalia e/ou alterações do SNC no RS. Métodos: Estudo descritivo dos 162 RN com microcefalia notificada no período de dezembro de 2015 a dezembro de 2016. Destes, 99 casos foram avaliados de forma retrospectiva com base em revisão de banco de dados, e 63 casos foram avaliados de forma prospectiva em ambulatório específico do HCPA-Brasil. As etapas propostas para a avaliação (ou informações coletadas dos bancos de dados) foram: 1) histórico da gestante; 2) exame físico do RN; 3) exames para pesquisa de infecção congênita – toxoplasmose, rubéola, ZIKV e CMV (reação de cadeia da polimerase - PCR ou sorológicos); 4) exames de imagem do SNC; 5) avaliação genética (para os casos com história familiar ou suspeita de alteração genética). As crianças foram avaliadas do nascimento até conclusão diagnóstica, seguimento perdido ou término do estudo. O período de avaliação das crianças não foi superior a quatro meses. Resultados: Noventa e cinco casos (58,6%) apresentavam microcefalia grave, resultando em uma prevalência desta complicação ao nascimento de 6.5/10.000 RN. A causa foi definida em 73 dos 162 casos. Destes eram infecções congênitas 31 casos (19.3%), síndromes genéticas 19 casos (11.7%), e malformação isolada do sistema nervoso central 20 casos (12,4%). E a causa não foi identificada em 89 (54,9%). Dos 31 casos com infecções congênitas, três (9.7%) foram diagnosticados com ZIKV, seis (19.3%) com citomegalovírus, oito (25,8%) com toxoplasmose, e 14 (45.2%) com sífilis congênita. Nenhum caso de rubeola congênita foi diagnosticado e a imunidade adquirida para rubeola das mães dos RN notificados foi de 91.6%. Destes casos 14 (45.1%) apresentaram baixo peso ao nascer e 21 (66.7%) eram pequenos para idade gestacional. A microcefalia grave foi identificada em 12 (38.7%) e 6 59.2% dos casos apresentaram alterações cerebrais, o que reforça a gravidade da ação das doenças infecciosas. Conclusão: Este é o primeiro estudo a avaliar os casos de microcefalia e/ou alterações do SNC durante o surto de ZIKV no RS. A prevalência de casos de ZIKV no RS foi inferior a estados do Nordeste do Brasil. A maioria dos casos de infecção congênita apresentaram lesões neurológicas graves, principalmente os casos de ZIKV, o que pode ocasionar atraso no desenvolvimento neurológico e sequelas nestas crianças ao longo da primeira infância. No entanto, salientamos a importância das demais infecções congênitas e causas desconhecidas associadas à microcefalia no RS, independente da presença de ZIKV. / Introduction: Microcephaly is a clinical sign associated with etiological heterogeneity. The main causes of microcephaly are congenital infections and congenital anomalies. The Ministry of Health (MOH) has instituted compulsory notification for newborns with microcephaly and / or Central Nervous System (CNS) disorders in 2015, following the zika virus (ZIKV) outbreak and the increase in cases of microcephaly. In Brazil, the geographical distribution of ZIKV occurred in a differentiated way in the northern and southern regions, and in the southernmost part of the country there were fewer infections due to this virus. Thus, the state of Rio Grande do Sul (RS) has become an important site for the systematic evaluation of the causes of microcephaly in this country, regardless of the presence of continuous transmission of ZIKV. Objectives: To evaluate and describe the causes of microcephaly of newborns notified by microcephaly and / or CNS changes in RS. Methods: Descriptive study of the 162 newborns with microcephaly reported from December 2015 to December 2016. Of these, 99 cases were retrospectively evaluated based on a database review, and 63 cases were evaluated prospectively in an outpatient clinic specific to HCPA-Brazil. The proposed steps for the evaluation (or information collected from the databases) were: 1) history of the pregnant woman; 2) physical examination of the newborn; 3) screening tests for congenital infection - toxoplasmosis, rubella, ZIKV and CMV (polymerase chain reaction - PCR or serological); 4) imaging studies of the CNS; 5) genetic evaluation (for cases with family history or suspected genetic alteration). The children were evaluated from birth to completion of diagnosis, missed follow-up or termination of the study. The evaluation of them was not more than four months. Results: Ninety-five cases (58.6%) presented severe microcephaly, resulting in a prevalence of this complication at birth of 6.5 / 10,000 newborn. A definite cause was established in 73 of the 162 causes. The leading etiology was congenital infections in 31 cases (19.3%), genetic syndromes in 19 cases (11.7%), and isolated central nervous system malformation in 20 cases (12.4%). Of the 31 cases with congenital infections, three (9.7%) were diagnosed with ZIKV, six (19.3%) with cytomegalovirus, eight (25.8%) with toxoplasmosis, and 14 (45.2%) with congenital syphilis. No case of congenital rubella was diagnosed and the acquired immunity to rubella from the mothers of the newborns was 91.6%. Of these, 14 (45.1%) had low birth 8 weight and 21 (66.7%) were small for gestational age. Severe microcephaly was identified in 12 (38.7%) and 59.2% of the cases presented cerebral alterations, which reinforces the severity of the action of infectious diseases. Conclusion: This is the first study to assess the cases of microcephaly and / or CNS changes during the outbreak of ZIKV in RS. The prevalence of ZIKV cases in RS was lower than in the northeastern states of Brazil. Most cases of congenital infection have severe neurological lesions, especially cases of ZIKV, which can cause delay in neurological development and detectable sequelae in these children throughout their first infancy. However, we emphasize the importance of other congenital infections and unknown causes associated with microcephaly in RS, regardless of the presence of ZIKV.

Les arbovirus sont un groupe de virus transmis par des vecteurs arthropodes contaminant chaque année plusieurs centaines de millions de personnes à travers le monde. De nombreux facteurs environnementaux, comme les xénobiotiques peuvent influencer la propagation des infections virales, la susceptibilité de l'hôte et la sévérité de l'infection. Parmi eux, le cadmium, métal toxique est connu pour moduler la résistance de l'hôte lors des infections par les arbovirus. Ces travaux de thèse se sont portés sur l'étude de l'alphavirus Sindbis et du flavivirus Zika infectant des cellules épithéliales humaines. Les résultats de cette thèse ont permis de démontrer que les cellules A549 étaient permissives à la souche épidémique de 2013 du virus Zika. Le virus se réplique efficacement et induit une apoptose de type mitochondriale dans les cellules A549. La réponse immunitaire innée des cellules a été caractérisée et le rôle des interférons de type I a été mis en avant. Ces résultats peuvent contribuer à une meilleure compréhension des mécanismes de pathogénicité de ce virus chez l'homme. Par la suite, les effets d'une exposition au cadmium lors des infections par les virus Sindbis et Zika ont été évalués. L'infection par le virus Zika n'a pas été modulée par l'exposition au cadmium in vitro. Mais de façon surprenante dans le cas de l'infection des cellules HEK 293, le cadmium a protégé les cellules des effets cytopathiques induits par le virus Sindbis. En présence de cadmium, l'apoptose induite par le virus a été inhibée et la réplication du virus Sindbis a été réduite. / Arboviruses are a group of viruses transmitted by arthropod vectors infecting hundreds of millions of people each year worldwide. Many environmental factors including xenobiotics can influence the spread, the susceptibility and the outcome of viral infections. Among them, cadmium, a toxic metal is known to affect the host resistance against arboviral infection. In this thesis, our work has been focused on studying the infection capability of the Sindbis alphavirus and the Zika flavivirus in human epithelial cells. The results demonstrated that A549 cells was permissive to the 2013 epidemic strain of Zika virus. The virus replicates efficiently leading to mitochondrial apoptosis. The innate immune response was characterized and the crucial role of type I interferon was highlighted. These results may contribute to a better understanding of Zika virus pathogenesis in humans. Thereafter, the effects of cadmium exposure on Sindbis virus and Zika virus infection was evaluated. Zika virus infection was not modulated by cadmium in vitro. Interestingly, cadmium protected the HEK 293 cells from the cytopathic effect induced by Sindbis virus. Cadmium exposure inhibited the apoptosis and reduced the viral replication.

<p dir="ltr">It is with great pleasure that I present the culmination of my exploration into the process of flavivirus assembly, with particular emphasis on the envelope glycoproteins and C protein of ZIKV and DENV2, within the subsequent four chapters of this dissertation.</p><p dir="ltr">Beginning in Chapter 2, we describe findings from a structure-function study of the ZIKV prM and E transmembrane helices (TMHs) and their role in virus assembly. Using a mutagenesis approach in a ZIKV reporter virus particle (RVP) system to increase throughput and discovery, substantial information was obtained showcasing a novel function for specific residues located within a short (4 residue) connecting region between the two TMHs of prM protein – denoted as the prM TMH “turn” residues. During translation of the prM and E proteins, these TMH “turn” residues face towards the cytosolic side of the ER membrane. This orientation has been hypothesized to possibly play a role during viral assembly interactions between the envelope glycoproteins and the nucleocapsid core of flaviviruses. However, no information to date has supported or refuted this theory. Overall, a single amino acid change within the prM TMH “turn” residues was found to be highly detrimental to viral assembly, ultimately leading to the loss of capsid integration into released sub viral particles and the alteration of the lipid membrane architecture. We surmised that lipid interactions around the region of the mutation were perturbed, leading to a loss of assembly capabilities but interestingly maintaining the budding mechanisms. The work of Chapter 2 will be submitted for publication to a peer reviewed journal shortly after the submission of this dissertation.</p><p dir="ltr">Chapter 3 expands on the ZIKV RVP results described in Chapter 2 by detailing a series of mutagenesis experiments into the role of the prM and E TMHs in the fully infectious ZIKV and DENV2 systems. Mutations within the prM TMH “turn” residues of DENV2 were found to also perturb virus infectivity, with two mutations within prM completely eliminating infectivity. The two mutants were found to be capable of producing NS5 and intracellular E protein that had been glycosylated, indicating that translation was intact and that E protein trafficking into the trans-Golgi network still occurred. However, unlike the results discussed in Chapter 2, the DENV2 mutants did not release any detectable E protein into their supernatants. This suggested that while the mutants could generate viral proteins and somehow undergo protein trafficking into the Golgi (signifying potential particle maturation), no particles were released. The DENV2 results were supported by reciprocal mutations in the prM proteins of ZIKV using fully infectious cDNA clones. The ZIKV prM mutants also eliminated virus infectivity and prevented the release of the E protein into the supernatant, indicating no release of viral particles, infectious or otherwise. Overall, the mutations in the fully infectious DNEV2 and ZIKV systems add further support for a novel role of the prM TMHs in flavivirus assembly.</p><p dir="ltr">Chapter 4 describes our efforts to reconstitute the flavivirus envelope glycoproteins into natively derived lipid nanoparticles for in vitro assembly analysis. Styrene-maleic acid copolymers (SMAs) were utilized for this study due to their ability to self-polymerize into highly hydrophobic chains in aqueous solutions. These hydrophobic chains can imbed themselves into lipid membranes to escape the aqueous environment, and in doing so “cut out” ~10nm diameter “patches” of native lipid membranes, along with any integrated membrane proteins. This “lipid/protein patch” is referred to as a styrene-maleic acid lipid nanoparticle (SMALP). Initially, attempts were made to generate SMALPs using purified Kunjin virus (KUNV) particles as the source of membrane lipids and glycoproteins due to their rapid growth rate and homogenous particle population. Unfortunately, attempts to generate SMALPs using purified KUNV were unsuccessful. It is hypothesized that the membrane curvature of purified KUNV particles generated a sterically and energetically unfavorable environment for SMALP generation, leading to the complete destruction of the particles during SMA mixing. To circumvent this issue, cells transfected with either WT or mutant ZIKV RVP cDNA were fractionated and purified ER membrane samples were mixed with SMAs to generate SMALPs. Western blot analysis suggested that the SMALP generation was successful. However, further experimentation is warranted to confirm this outcome and the structural integrity of the envelope glycoproteins within the SMALP.</p><p dir="ltr">Chapter 5 describes collaborative work on the identification of a novel compound inhibitor against flavivirus assembly, specifically targeting C protein’s interactions with RNA. This work was done in conjunction with a visiting scholar from the Indian Institute of Technology Mandi – Dr. Prateek Kumar – during his time at Purdue University from August 2022-May 2023. Much of the foundational computation work was done by Prateek prior to his arrival at Purdue University. As such, while the full context and results for the entirety of the study will be discussed, this chapter will primarily focus on the in vitro experimental results that were gathered directly by me, or results that were produced by Prateek and myself equally. This chapter demonstrates that a novel small molecule inhibitor against ZIKV C protein can, in fact, diminish ZIKV assembly by impeding C protein’s binding to RNA, prevent efficient RNA replication through binding and disruption of NS2B/3 protease, and perturb virus binding and entry prior to infection by also binding to E protein. Moreover, the novel molecule was also found to disrupt DENV2 infection as well, albeit to a lesser degree than ZIKV. This multifaceted molecule was recommended for further study in animal systems to continue testing its safety and efficacy for treatment of ZIKV and DENV2 in humans. A co-authorship manuscript has been completed on the work from this chapter and is currently awaiting submission to a peer reviewed journal.</p><p dir="ltr">Finally, Chapter 6 will combine the conclusions from the above chapters and discuss, in detail, aspects pertaining to the future of studies aiming to better understand the assembly of flaviviruses. This chapter will focus on how the link between viral assembly and membrane lipid architecture fits with previously established literature and what future directions could be employed to answer the questions proposed within.</p>

As principais matérias primas necessárias para a preparação de testes diagnósticos são as proteínas dos patógenos que necessariamente apresentem as estruturas nativas. O objetivo do presente estudo foi a obtenção das proteínas não estruturais 1 (NS1) dos vírus da dengue (DENV) e da zika (ZIKV) a partir dos corpúsculos de inclusão (CI) produzidos em bactérias Escherichia coli. Mostramos que a combinação de alta pressão hidrostática (APH) e pH alcalino é eficiente para a solubilização de NS1-CI. A incubação em 2,4 kbar das suspensões de NS1-CI em pH alcalino mostrou-se eficiente para a solubilização da NS1. A presença de Arg promove a dissociação de oligômeros. A aplicação de 2,4 kbar às suspensões de NS1-CI em pH de 10,5 (DENV) e de 11,5 (ZIKV) na presença de Arg e um par redox, seguida de diálise em tampão em pH 8,5, foram as condições escolhidas para o reenovelamento de NS1. Obtivemos ambas NS1 com rendimentos entre 75% e 90% em relação às quantidades totais das proteínas presente nos correspondentes CI de NS1. As NS1 reenoveladas apresentaram reatividade comparável às proteínas obtidas utilizando um protocolo convencional estabelecido, com rendimentos mais de 25 vezes superiores. Foi obtido um processo altamente eficiente para o reenovelamento de NS1 apresentando características biológicas preservadas em relação a reatividade com anticorpos específicos de antígeno, incluindo soro de paciente infectado com zikv e que, portanto, podem ser usados como antígeno para o desenvolvimento de vacinas ou testes de diagnóstico. Além disso, este estudo descreve a criação de um processo inovador, que é a utilização concomitante de APH e pH alcalino, para solubilização e posterior reenovelamento de NS1-CI que podem ser utilizados para outras proteínas relevantes. / The main products for the preparation of diagnostic tests are as proteins of the pathogens that necessarily present as the native structures. The objective of the present study was to obtain non-structural proteins 1 (NS1) from dengue virus (DENV) and zika virus (ZIKV) from the inclusion bodies (IBs) produced in Escherichia coli bacteria. We show that it is a combination of high hydrostatic pressure (HHP) and alkaline pH is efficient for a solubilization of NS1-IB. A 2.4 kbar incubation of NS1-IB suspensions at alkaline pH proved to be efficient for NS1 solubilization. The presence of Arg promotes the dissociation of oligomers. The application of 2.4 kbar to the suspensions of NS1-IB at pH 10.5 (DENV) and 11.5 (ZIKV) in the presence of Arg and a redox pair, dialysis in pH 8.5 buffer were as conditions chosen for the refolding of NS1. We obtained both NS1 at yields between 75% and 90% relative to the total amounts of the proteins present in the corresponding NS1 IB. Refolded NS1 showed similar to proteins obtained using an established standard protocol, with yields more than 25 times higher. A highly efficient process for the refolding of NS1 was obtained with preserved biological features regarding reactivity with antigen-specific antibodies, including sera of zikv-infected patients and that can be used as antigen for the development of vaccines or diagnostic tests. In addition, this study describes the creation of an innovative process, which is a concomitant use of HHP and alkaline pH, for solubilization and subsequent refolding of NS1-IB that can be used for other relevant proteins.

O zika é um arbovírus emergente. Há evidências para a relação entre o zika e a microcefalia congênita e também com a síndrome de Guillain-Barre. Várias características do vírus são importantes, como a persistência do vírus no sêmen por vários meses, transmissão sexual e evidência de transmissão pré-natal. As mães grávidas infectadas com zika podem dar à luz crianças aparentemente saudáveis que podem apresentar manifestações e complicações tardias. Existe uma clara necessidade de diagnosticar e sequenciar amostras clínicas do ZIKV que circulam na América do Sul, especificamente no Brasil. No entanto, as baixas cargas virais observadas que são observadas comumente em amostras humanas constituem um fator complicador para detecção, amplificação e sequenciamento. Neste projeto, propor projetar um fluxo de trabalho otimizado para o sequenciamento completo do genoma com base no pré-enriquecimento por PCR (reação em cadeia da polimerase) e pools de amplicons. / Zika is an emerging arbovirus. There is enough evidence for the relation between Zika and congenital microcephaly and also with the Guillain-Barre syndrome. Several characteristics of the virus are important, such as persistence of the virus in semen for several months, sexual transmission and evidence of prenatal transmission. Zika infected pregnant mothers may give birth to apparently healthy children that may show late manifestations and complications. There is a clear necessity of diagnosing and sequencing clinical samples of ZIKV circulating in South America, specifically in Brazil. Nevertheless, the observed low viral loads that are commonly in human samples constitute a complicating factor for detection, amplification and sequencing. In this project, we aim to design an optimized workflow for full genome sequencing based on pre-enrichment by PCR (polymerase chain reaction) and amplicon pools.

As principais matérias primas necessárias para a preparação de testes diagnósticos são as proteínas dos patógenos que necessariamente apresentem as estruturas nativas. O objetivo do presente estudo foi a obtenção das proteínas não estruturais 1 (NS1) dos vírus da dengue (DENV) e da zika (ZIKV) a partir dos corpúsculos de inclusão (CI) produzidos em bactérias Escherichia coli. Mostramos que a combinação de alta pressão hidrostática (APH) e pH alcalino é eficiente para a solubilização de NS1-CI. A incubação em 2,4 kbar das suspensões de NS1-CI em pH alcalino mostrou-se eficiente para a solubilização da NS1. A presença de Arg promove a dissociação de oligômeros. A aplicação de 2,4 kbar às suspensões de NS1-CI em pH de 10,5 (DENV) e de 11,5 (ZIKV) na presença de Arg e um par redox, seguida de diálise em tampão em pH 8,5, foram as condições escolhidas para o reenovelamento de NS1. Obtivemos ambas NS1 com rendimentos entre 75% e 90% em relação às quantidades totais das proteínas presente nos correspondentes CI de NS1. As NS1 reenoveladas apresentaram reatividade comparável às proteínas obtidas utilizando um protocolo convencional estabelecido, com rendimentos mais de 25 vezes superiores. Foi obtido um processo altamente eficiente para o reenovelamento de NS1 apresentando características biológicas preservadas em relação a reatividade com anticorpos específicos de antígeno, incluindo soro de paciente infectado com zikv e que, portanto, podem ser usados como antígeno para o desenvolvimento de vacinas ou testes de diagnóstico. Além disso, este estudo descreve a criação de um processo inovador, que é a utilização concomitante de APH e pH alcalino, para solubilização e posterior reenovelamento de NS1-CI que podem ser utilizados para outras proteínas relevantes. / The main products for the preparation of diagnostic tests are as proteins of the pathogens that necessarily present as the native structures. The objective of the present study was to obtain non-structural proteins 1 (NS1) from dengue virus (DENV) and zika virus (ZIKV) from the inclusion bodies (IBs) produced in Escherichia coli bacteria. We show that it is a combination of high hydrostatic pressure (HHP) and alkaline pH is efficient for a solubilization of NS1-IB. A 2.4 kbar incubation of NS1-IB suspensions at alkaline pH proved to be efficient for NS1 solubilization. The presence of Arg promotes the dissociation of oligomers. The application of 2.4 kbar to the suspensions of NS1-IB at pH 10.5 (DENV) and 11.5 (ZIKV) in the presence of Arg and a redox pair, dialysis in pH 8.5 buffer were as conditions chosen for the refolding of NS1. We obtained both NS1 at yields between 75% and 90% relative to the total amounts of the proteins present in the corresponding NS1 IB. Refolded NS1 showed similar to proteins obtained using an established standard protocol, with yields more than 25 times higher. A highly efficient process for the refolding of NS1 was obtained with preserved biological features regarding reactivity with antigen-specific antibodies, including sera of zikv-infected patients and that can be used as antigen for the development of vaccines or diagnostic tests. In addition, this study describes the creation of an innovative process, which is a concomitant use of HHP and alkaline pH, for solubilization and subsequent refolding of NS1-IB that can be used for other relevant proteins.