Project description:Use of the bacterium Wolbachia is an innovative new strategy designed to break the cycle of dengue transmission. There are two main mechanisms by which Wolbachia could achieve this: by reducing the level of dengue virus in the mosquito and/or by shortening the host mosquito's lifespan. However, although Wolbachia shortens the lifespan, it also gives a breeding advantage which results in complex population dynamics. This study focuses on the development of a mathematical model to quantify the effect on human dengue cases of introducing Wolbachia into the mosquito population. The model consists of a compartment-based system of first-order differential equations; seasonal forcing in the mosquito population is introduced through the adult mosquito death rate. The analysis focuses on a single dengue outbreak typical of a region with a strong seasonally-varying mosquito population. We found that a significant reduction in human dengue cases can be obtained provided that Wolbachia-carrying mosquitoes persist when competing with mosquitoes without Wolbachia. Furthermore, using the Wolbachia strain WMel reduces the mosquito lifespan by at most 10% and allows them to persist in competition with non-Wolbachia-carrying mosquitoes. Mosquitoes carrying the WMelPop strain, however, are not likely to persist as it reduces the mosquito lifespan by up to 50%. When all other effects of Wolbachia on the mosquito physiology are ignored, cytoplasmic incompatibility alone results in a reduction in the number of human dengue cases. A sensitivity analysis of the parameters in the model shows that the transmission probability, the biting rate and the average adult mosquito death rate are the most important parameters for the outcome of the cumulative proportion of human individuals infected with dengue.
Project description:Wolbachia pipientis is an obligate intracellular bacterium capable of spreading itself through populations by manipulating the reproduction of its hosts. The Wolbachia strain wMelPop, which reduces longevity in Drosophila melanogaster, has been introduced into the Dengue virus mosquito vector, Aedes aegypti, as a strategy to reduce disease transmission. The infecting Wolbachia halve the lifespan of the mosquito and induce numerous behavioral and physiological abnormalities that reduce the ability of the mosquito to successfully obtain a blood meal. We aim to understand the mechanism underpinning these changes and hence have chosen to explore how Wolbachia may be interacting with the insects nervous and muscle tissue. We carried out a series whole genome profiling experiments based on head and muscle tissues to identify mosquito pathways affected by the microbe.
Project description:The dengue virus (DENV) cause frequent epidemics infecting ~390 million people annually in over 100 countries. There are no approved vaccines or antiviral drugs for treatment of infected patients. However, there is a novel approach to control transmission of DENV by the mosquito vectors, Aedes aegypti and Ae. albopictus, using Wolbachia symbiont. The wMelPop strain of Wolbachia suppresses DENV transmission and shortens the mosquito life span. However, the underlying mechanism is poorly understood. To clarify this mechanism, either naïve Ae. albopictus (C6/36) or wMelPop-C6/36 cells were infected with DENV2. Analysis of host transcript profiles by RNAseq revealed that the presence of wMelPop had profound effects on mosquito host cell transcription in response to DENV2 infection. The viral RNA evolved from wMelPop-C6/36 contained low frequency mutations (~25%) within the coding region of transmembrane domain-1 (TMD1) of E protein. Mutations with >97 % frequencies were distributed within other regions of E, NS5 RNA-dependent RNA polymerase (NS5POL) domain, the TMDs of NS2A, NS2B, and NS4B. Moreover, while DENV2-infected naïve C6/36 cells showed syncytia formation, DENV2-infected wMelPop-C6/36 cells did not. The Wolbachia-induced mutant DENV2 can readily infect and replicate in naïve C6/36 cells; whereas, in the mutant DENV2- infected BHK-21 or Vero cells, the virus replication was delayed. In LLC-MK2 cells, the mutant failed to produce plaques. Additionally, in BHK-21 cells, many mutations in the viral genome reverted to WT and compensatory mutations in NS3 gene appeared. Our results suggest that wMelPop impacts significantly the interactions of DENV2 with mosquito and mammalian host cells.
Project description:Wolbachia are intracellular maternally inherited bacteria that can spread through insect populations and block virus transmission by mosquitoes, providing an important new dengue control strategy. To better understand the mechanisms of virus inhibition, proteomic quantification of the effects of Wolbachia in mosquito (Aedes aegypti) midguts was performed.
Project description:The following dataset is a Wolbachia proteome derived from protein extractions of infected ovaries of the mosquito host Culex pipiens.
Project description:Zika virus is a global public health emergency due to its association with microcephaly, Guillain-Barré syndrome, neuropathy, and myelitis in children and adults. A total of 87 countries have had evidence of autochthonous mosquito-borne transmission of Zika virus, distributed across four continents, and no antivirus therapy or vaccines are available. Therefore, several strategies have been developed to target the main mosquito vector, Aedes aegypti, to reduce the burden of different arboviruses. Among such strategies, the use of the maternally-inherited endosymbiont Wolbachia pipientis has been applied successfully to reduce virus susceptibility and decrease transmission. However, the mechanisms by which Wolbachia orchestrate resistance to ZIKV infection remains to be elucidated. In this study, we apply quantitative isobaric mass spectrometry-based proteomics to quantify proteins and identify pathways altered during ZIKV infection; Wolbachia infection; co-infection with Wolbachia/ZIKV in the Ae. aegypti. We show that Wolbachia regulates proteins involved in ROS production, regulates humoral immune response, and antioxidant production. The reduction of ZIKV polyprotein in the presence of Wolbachia in the mosquitoes was determined by mass spectrometry and corroborates the idea that Wolbachia helps to block ZIKV infections in Ae. aegypti. The present study offers a rich resource of data to help elucidate mechanisms by which Wolbachia orchestrate resistance to ZIKV infection in Ae. aegypti.
Project description:Cellular models have provided significant advances on molecular bases of bipartite interactions between either an arbovirus or a bacterial symbiont with a given arthropod vector. However, although an interference phenomenon was evidenced in tripartite interaction arbovirus-symbiont-mosquito vector very little is known regarding the mechanisms involved. Using large-scale proteome profiling, we characterized proteins differentially expressed in Aedes albopictus cells infected by the symbiotic bacterium Wolbachia and the Chikungunya virus (CHIKV). These proteins were mostly related to cellular processes involved in glycolysis process, protein metabolism, translation and amino acid metabolism. The presence of Wolbachia impacted significantly the protein profiles, including sequestration of proteins such as structural polyprotein and capsid viral proteins that may affect replication and assembly of CHIKV in cellulo. This study provides insights into the molecular pathways involved in the tripartite interaction mosquito-Wolbachia-virus and may help in defining targets for the better implementation of Wolbachia-based strategy for disease transmission control.
Project description:Wolbachia endosymbionts are widespread intracellular, maternally inherited bacteria which manipulate the host to favour their spread through a population. Cytoplasmic incompatibility (CI) and viral suppression are two such manipulations driven by uncharacterised mechanisms. To gain insight into potential molecular mechanisms responsible for these effects, we performed the first in-depth proteomic characterisation of the host response to Wolbachia infection. We find that the presence of the Wolbachia wMelPop in Aedes aegypti mosquito cells alters levels of proteins involved in cell cycle control, DNA replication, autophagy, vesicular trafficking, iron homeostasis, amino acid degradation, purine metabolism, lipid metabolism and immunity. The majority of the cell cycle/DNA replication proteins were downregulated in the presence of Wolbachia, in particular, a member of the anoctamin family was strongly down regulated which may be related to the chromosomal segregation defects observed in CI crosses. We found clear evidence for perturbed lipid metabolism, Wolbachia infected cells expressed higher levels of Apolipoprotein D and the cholesterol efflux transporter ABCA1, while the LDL receptor and fatty acid synthase were downregulated. ABCA1 was also upregulated at the mRNA level in adult Wolbachia infected Aedes aegypti mosquitoes. Wolbachia therefore perturbs cholesterol homeostasis causing the host cell to respond to an apparent cholesterol excess which may contribute to viral inhibition.
Project description:Certain strains of the intracellular endosymbiont Wolbachia can strongly inhibit or block the transmission of viruses such as dengue by Aedes mosquitoes, and the mechanisms responsible are still not well understood. Direct infusion and liquid chromatography FT-ICR mass spectrometry based lipidomicse DIMS and LCMS analyses were conducted using Aedes albopictus Aa23 cells that were infected with the wMel and wMelPop strains of Wolbachia compared to uninfected cells. Substantial shifts in the cellular lipid profile were apparent in the presence of Wolbachia. Most significantly, sphingolipids were depleted across all classes, and some reduction in diacylglyerol fatty acids and phosphatidylcholines was also observed. These lipid classes have previously been shown to be selectively enriched in DENV-infected mosquito cells, suggesting that Wolbachia may produce a cellular lipid environment that is antagonistic to viral replication. The data improve understanding of the intracellular interactions between Wolbachia and mosquitoes.
Project description:Zika is a vector-borne disease caused by an arbovirus (ZIKV) and overwhelmingly transmitted by Ae. aegypti. This disease is linked to adverse fetal outcomes, mostly microcephaly in newborns, and other clinical aspects such as acute febrile illness and neurologic complications, for example Guillain-Barré syndrome. One of the actual most promising strategies to mitigate arbovirus transmission involves releasing Ae. aegypti mosquitoes carrying the maternally inherited endosymbiont bacteria Wolbachia pipientis. The presence of Wolbachia is associated with a reduced susceptibility to arboviruses and a fitness cost in mosquito life-history traits as fecundity and fertility. However, the mechanisms by which Wolbachia influences metabolic pathways leading to differences in egg production remains poorly known. In order to investigate the impact of co-infections on the reproductive tract of the mosquito, we applied a quantitative proteomic strategy based on an isobaric labeling to investigate the influence of Wolbachia wMel and ZIKV infection in Ae. aegypti ovaries. For what we know, this is the most complete proteome of Ae. aegypti ovaries reported so far, with a total of 3913 proteins identified. We were able to quantify a total of 1044 Wolbachia proteins in complex sample tissue of Ae. aegypti ovary employing mass spectrometry-based quantitative methods. Furthermore, we describe and discuss proteins and pathways altered in Ae. aegypti during ZIKV infections, Wolbachia infections, co-infection Wolbachia/ZIKV, and compared with no infection, focusing on immune and reproductive aspects of Ae. aegypti.