Project description:This study is to assess the safety, tolerability, and biomarkers of protection in healthy malaria-naive adults, who will receive bites from Anopheles stephensi mosquitoes either infected with Plasmodium falciparum Sporozoites (PfRAS) (true-immunization) or noninfected (mock-immunization).
Project description:This study is to assess the safety, tolerability, and biomarkers of protection in healthy malaria-naive adults, who will receive bites from Anopheles stephensi mosquitoes either infected with Plasmodium falciparum Sporozoites (PfRAS) (true-immunization) or noninfected (mock-immunization).
Project description:This study is to assess the safety, tolerability, and biomarkers of protection in healthy malaria-naive adults, who will receive bites from Anopheles stephensi mosquitoes either infected with Plasmodium falciparum Sporozoites (PfRAS) (true-immunization) or noninfected (mock-immunization).
Project description:Mosquitoes possess an innate immune system that is capable of limiting infection by a variety of pathogens, including the Plasmodium spp. parasites responsible for human malaria. The Anopheles immune deficiency (IMD) innate immune signaling pathway confers resistance to Plasmodium falciparum. While some previously identified Anopheles anti-Plasmodium effectors are regulated through signaling by Rel2, the transcription factor of the IMD pathway, many components of this defense system remain uncharacterized. To begin to better understand the regulation of immune effector proteins by the IMD pathway, we used oligonucleotide microarrays and iTRAQ to analyze differences in mRNA and protein expression, respectively, between transgenic An. stephensi mosquitoes exhibiting blood meal-inducible overexpression of an active recombinant Rel2 and their wild-type conspecifics. Numerous genes were differentially regulated at both the mRNA and protein levels following induction of Rel2. While multiple immune genes were up-regulated, a majority of the differentially expressed genes have no known immune function in mosquitoes. Identified sequences were assigned putative functions and gene ontology (GO) terms based on homology to previously annotated A. gambiae gene sequences. Selected up-regulated genes from multiple GO categories were tested for both anti-Plasmodium and anti-bacterial action using RNA interference (RNAi). Based on our experimental findings, we conclude that increased expression of the IMD immune pathway-controlled transcription factor Rel2 affects the expression of numerous genes with diverse functions, suggesting a broader physiological impact of immune activation and possible functional versatility of Rel2. Our study has identified multiple novel anti-Plasmodium effectors. Midguts from midgut-specific transgenic A. stephensi at 6 and 12 hours post-blood meal and fat bodies from fat body-specific transgenic A. stephensi at 12 and 18 hours post-blood meal were compared to wild-type A. stephensi at the same time points. 3 biological replicates and 1 pseudo-replicate per array.
Project description:Malaria is as one of the most debilitating mosquito-borne global health burdens. While much of the malaria and mosquito-borne disease attention have focused on Africa, South East Asia accounts for a sizable portion of the malaria global burden. Moreover, about 50% of the Asian malaria incidence and deaths have been from India. The completion of genome sequence of Anopheles stephensi, a major malaria vector in Asia, offers new opportunities for global health innovation, not to mention for progress in deciphering the vectorial ability of this mosquito species at a molecular level. Moving forward, tissue-based expression profiling would be the next obvious step in understanding gene functions of Anopheles stephensi. We report here the first study, to the best of our knowledge, on transcriptomic profile of four important organs of an adult female Anopheles stephensi mosquito (midgut, Malpighian tubules, fat body and ovary). In all, we identified over 21,000 transcripts corresponding to more than 12,000 gene loci from these four tissues. This study provides the tissue-based expression profiles of majority of annotated transcripts in Anopheles stephensi genome, and the dynamics of alternative splicing in these tissues. Understanding the transcript expression and gene function at the tissue level would immensely help in enhancing our knowledge of this important vector and decipher the putative role of these tissues. This knowledge might in turn provide the basis of selection of candidates for future studies on vectorial ability and novel molecular targets to intercept malaria transmission.
Project description:In the present study, we have investigated the effect of CpG Oligodeoxynucleotides (CpG-ODN) on the outcome of Plasmodium infection of the mosquito vectors Anopheles stephensi and Anopheles gambiae and on the modulation of mosquito immunity to Plasmodium. Anopheles mosquitoes inoculated with CpG-ODN showed significant reduction of Plasmodium infection rate and intensity. Microarrays were used to profile transcription of fat-body from CpG-ODN-treated mosquitoes. Mosquitoes were dissected 18h after ODN inoculation (immediately before feeding). Batches of 20 to 30 fat bodies (abdomen without midgut, ovaries and malpighian tubule]) were dissected in cold DEPC-treated phosphate-buffered saline (PBS) and processed for RNA preparation. Mosquitoes treated with CpG-ODNs are less susceptible to Plasmodium infection. Transcription profile of fat body indicates that protection was associated with coagulation/wound healing, while melanization appears to be depressed.
Project description:Upon water loss, some organisms pause their life cycles and escape death. While widespread in microbes, this is less common in animals. Aedes mosquitoes are vectors for viral diseases. Aedes eggs can survive dry environments, but molecular and cellular principles enabling egg survival through desiccation remain unknown. In this report, we find that Aedes aegypti eggs, in contrast to Anopheles stephensi, survive desiccation by acquiring desiccation tolerance at a late developmental stage. We uncover unique proteome and metabolic state changes in Aedes embryos during desiccation that reflect reduced central carbon metabolism, rewiring towards polyamine production, and enhanced lipid utilization for energy and polyamine synthesis. Using inhibitors targeting these processes in blood-fed mosquitoes that lay eggs, we infer a two-step process of desiccation tolerance in Aedes eggs. The metabolic rewiring towards lipid breakdown and dependent polyamine accumulation confers resistance to desiccation. Furthermore, rapid lipid breakdown is required to fuel energetic requirements upon water re-entry to enable larval hatching and survival upon rehydration. This study is fundamental to understanding Aedes embryo survival and in controlling the spread of these mosquitoes.
