Zika virus infection:in vitro models of disease pathogenesis

In this thesis, we established primary and cell line models to study the pathogenesis of the Zika virus. These models are important not only to identify markers of disease pathogenesis but also to screen the antiviral activity of various drugs

Global Citizenship Skills among University Students and its Relationship with their Identity Orientation

Major purpose of the current study was to examine the prevalence of global citizenship skills among university students in Pakistan and its relationship with their identity orientations. Three indicators of global citizenship including social responsibility, global competence and global civic engagement were accepted to execute the research objective. The study followed four aspects of identity orientations including personal, social, collective and relational orientations. 324 students enrolled in selected Pakistani public sector universities participated in the study. Aspects of Identity Questionnaire (AIQ-IV) developed by Cheek and Briggs (2013) and global citizenship scale developed by Morais and Ogden (2011) were adapted as research instruments to collected the required data. Results show the prevalence of global civic engagement and social responsibility is comparatively lesser among the participants than other global citizenship skills. The students supported all four types of identity orientations. The study concludes that the four identity orientations have significant and direct associations with major global citizenship skills

Comparative Analysis of In Vitro Models to Study Antibody-Dependent Enhancement of Zika Virus Infection

During the 2015–2016 outbreak of Zika virus (ZIKV) in the Americas, a previously unknown severe complication of ZIKV infection during pregnancy resulting in birth defects was reported. Since the ZIKV outbreak occurred in regions that were highly endemic for the related dengue virus (DENV), it was speculated that antibody-dependent enhancement (ADE) of a ZIKV infection, caused by the presence of cross-reactive DENV antibodies, could contribute to ZIKV disease severity. Emerging evidence indicates that, while in vitro models can show ADE of ZIKV infection, ADE does not seem to contribute to congenital ZIKV disease severity in humans. However, the role of ADE of ZIKV infection during pregnancy and in vertical ZIKV transmission is not well studied. In this study, we hypothesized that pregnancy may affect the ability of myeloid cells to become infected with ZIKV, potentially through ADE. We first systematically assessed which cell lines and primary cells can be used to study ZIKV ADE in vitro, and we compared the difference in outcomes of (ADE) infection experiments between these cells. Subsequently, we tested the hypothesis that pregnancy may affect the ability of myeloid cells to become infected through ADE, by performing ZIKV ADE assays with primary cells isolated from blood of pregnant women from different trimesters and from age-matched non-pregnant women. We found that ADE of ZIKV infection can be induced in myeloid cell lines U937, THP-1, and K562 as well as in monocyte-derived macrophages from healthy donors. There was no difference in permissiveness for ZIKV infection or ADE potential of ZIKV infection in primary cells of pregnant women compared to non-pregnant women. In conclusion, no increased permissiveness for ZIKV infection and ADE of ZIKV infection was found using in vitro models of primary myeloid cells from pregnant women compared to age-matched non-pregnant women

The possible role of cross-reactive dengue virus antibodies in Zika virus pathogenesis

Zika virus (ZIKV) has been known for decades to circulate in Africa and Asia. However, major complications of a ZIKV infection have recently become apparent for reasons that are still not fully elucidated. One of the hypotheses for the seemingly increased pathogenicity of ZIKV is that cross-reactive dengue antibodies can enhance a ZIKV infection through the principle of antibody-dependent enhancement (ADE). Recently, ADE in ZIKV infection has been studied, but conclusive evidence for the clinical importance of this principle in a ZIKV infection is lacking. Conversely, the widespread circulation of ZIKV in dengue virus (DENV)-endemic regions raises new questions about the potential contribution of ZIKV antibodies to DENV ADE. In this review, we summarize the results of the evidence to date and elaborate on other possible detrimental effects of cross-reactive flavivirus antibodies, both for ZIKV infection and the risk of ZIKV-related congenital anomalies, DENV infection, and dengue hemorrhagic fever

Zika virus infection perturbs osteoblast function

Zika virus (ZIKV) infection is typically characterized by a mild self-limiting disease presenting with fever, rash, myalgia and arthralgia and severe fetal complications during pregnancy such as microcephaly, subcortical calcifications and arthrogyropsis. Virus-induced arthralgia due to perturbed osteoblast function has been described for other arboviruses. In case of ZIKV infection, the role of osteoblasts in ZIKV pathogenesis and bone related pathology remains unknown. Here, we study the effect of ZIKV infection on osteoblast differentiation, maturation and function by quantifying activity and gene expression of key biomarkers, using human bone marrow-derived mesenchymal stromal cells (MSCs, osteoblast precursors). MSCs were induced to differentiate into osteoblasts and we found that osteoblasts were highly susceptible to ZIKV infection. While infection did not cause a cytopathic effect, a significant reduction of key osteogenic markers such as ALP, RUNX2, calcium contents and increased expression of IL6 in ZIKV-infected MSCs implicated a delay in osteoblast development and maturation, as compared to uninfected controls. In conclusion, we have developed and characterized a new in vitro model to study the role of bone development in ZIKV pathogenesis, which will help to identify possible new targets for developing therapeutic and preventive measures

Zika virus infection induces elevation of tissue factor production and apoptosis on human umbilical vein endothelial cells

Zika virus (ZIKV) infection is typically characterized by a mild disease presenting with fever, maculopapular rash, headache, fatigue, myalgia, and arthralgia. A recent animal study found that ZIKV-infected pregnant Ifnar-/-mice developed vascular damage in the placenta and reduced amount of fetal capillaries. Moreover, ZIKV infection causes segmental thrombosis in the umbilical cord of pregnant rhesus macaques. Furthermore, several case reports suggest that ZIKV infection cause coagulation disorders. These results suggest that ZIKV could cause an alteration in the host hemostatic response, however, the mechanism has not been investigated thus far. This paper aims to determine whether ZIKV infection on HUVECs induces apoptosis and elevation of tissue factor (TF) that leads to activation of secondary hemostasis. We infected HUVECs with two ZIKV strains and performed virus titration, immunostaining, and flow cytometry to confirm and quantify infection. We measured TF concentrations with flow cytometry and performed thrombin generation test (TGT) as a functional assay to assess secondary hemostasis. Furthermore, we determined the amount of cell death using flow cytometry. We also performed enzyme-linked immunosorbent assay (ELISA) to determine interleukin (IL)-6 and IL-8 production and conducted blocking experiments to associate these cytokines with TF expression. Both ZIKV strains infected and replicated to high titers in HUVECs. We found that infection induced elevation of TF expressions. We also showed that increased TF expression led to shortened TGT time. Moreover, the data revealed that infection induced apoptosis. In addition, there was a significant increase of IL-6 and IL-8 production in infected cells. Here we provide in vitro evidence that infection of HUVECs with ZIKV induces apoptosis and elevation of TF expression that leads to activation of secondary hemostasis

Zika Virus Seroprevalence in Urban and Rural Areas of Suriname, 2017

In 2015-2016, a Zika virus (ZIKV) outbreak occurred in the Americas. In 2017, we conducted a ZIKV serosurvey in Suriname in which 770 participants were recruited from 1 urban area and 2 rural villages in the tropical rainforest. All collected samples were tested for presence of ZIKV antibodies using a ZIKV immunoglobulin G enzyme-linked immunosorbent assay and a virus neutralization assay. We found that 35.1% of the participants had neutralizing antibodies against ZIKV. In 1 remote village in the rainforest, 24.5% of the participants had neutralizing antibodies against ZIKV, suggesting that ZIKV was widely sprea