Project description:Background: The mosquito Anopheles gambiae is a major vector of human malaria. Increasing evidence indicates that blood cells (hemocytes) comprise an essential arm of the mosquito innate immune response against both bacteria and malaria parasites. To further characterize the role of hemocytes in mosquito immunity, we undertook the first genome-wide transcriptomic analyses of adult female An. gambiae hemocytes following infection by two species of bacteria and a malaria parasite. Results: We identified 4047 genes expressed in hemocytes, using An. gambiae genome-wide microarrays. While 279 transcripts were significantly enriched in hemocytes relative to whole adult female mosquitoes, 959 transcripts exhibited immune challenge-related regulation. The global transcriptomic responses of hemocytes to challenge with different species of bacteria and/or different stages of malaria parasite infection revealed discrete, minimally overlapping, pathogen-specific signatures of infection-responsive gene expression; 105 of these represented putative immunity-related genes including anti-Plasmodium factors. Of particular interest was the specific co-regulation of various members of the Imd and JNK immune signaling pathways during malaria parasite invasion of the mosquito midgut epithelium. Conclusion: Our genome-wide transcriptomic analysis of adult mosquito hemocytes reveals pathogen-specific signatures of gene regulation and identifies several novel candidate genes for future functional studies.
Project description:Insect hemocytes mediate important cellular immune responses including phagocytosis and encapsulation, and also secrete immune factors such as opsonins, melanization factors, and antimicrobial peptides. In Anopheles, they contribute to the defense against malaria parasite invasion during the early sporogonic cycle. We used microarrays to identify if and to what degree circulating hemocytes have altered global expression profiles after infection with the rodent malaria parasite, Plasmodium berghei
Project description:Insect hemocytes mediate important cellular immune responses including phagocytosis and encapsulation, and also secrete immune factors such as opsonins, melanization factors, and antimicrobial peptides. In Anopheles, they contribute to the defense against malaria parasite invasion during the early sporogonic cycle. We used microarrays to identify if and to what degree circulating hemocytes have altered global expression profiles after infection with the rodent malaria parasite, Plasmodium berghei Hemocytes were isolated 24-28h after infection using the infectious EGFP-CON P. berghei strain (experiment) or an invasion-deficient, Circumsporozoite- and TRAP-related protein (CTRP) knockout strain with the same genetic background as GFP-CON (CTRPko/GFP, control).
Project description:Background: The mosquito Anopheles gambiae is a major vector of human malaria. Increasing evidence indicates that blood cells (hemocytes) comprise an essential arm of the mosquito innate immune response against both bacteria and malaria parasites. To further characterize the role of hemocytes in mosquito immunity, we undertook the first genome-wide transcriptomic analyses of adult female An. gambiae hemocytes following infection by two species of bacteria and a malaria parasite. Results: We identified 4047 genes expressed in hemocytes, using An. gambiae genome-wide microarrays. While 279 transcripts were significantly enriched in hemocytes relative to whole adult female mosquitoes, 959 transcripts exhibited immune challenge-related regulation. The global transcriptomic responses of hemocytes to challenge with different species of bacteria and/or different stages of malaria parasite infection revealed discrete, minimally overlapping, pathogen-specific signatures of infection-responsive gene expression; 105 of these represented putative immunity-related genes including anti-Plasmodium factors. Of particular interest was the specific co-regulation of various members of the Imd and JNK immune signaling pathways during malaria parasite invasion of the mosquito midgut epithelium. Conclusion: Our genome-wide transcriptomic analysis of adult mosquito hemocytes reveals pathogen-specific signatures of gene regulation and identifies several novel candidate genes for future functional studies. In order to identify hemocyte-specific and immune-responsive transcripts, we first compared transcripts expressed in hemocytes from one day old sugar-fed mosquitoes to transcripts detected in whole mosquitoes of the same age and feeding status. This resulted in identification of the hemocyte-enriched transcriptome. We then compared hemocytes from 1 day old mosquitoes, 1 hour after immune challenge with heat-killed Escherichia coli or Micrococcus luteus, to control female mosquitoes injected with sterile PBS to determine the bacteria challenge responsive transcriptomes. We used heat-killed bacteria in these assays, because our primary interest was in identifying the bacterial responsive transcriptome and to avoid the potentially confounding effects of altered gene expression due to the lethal effects of a systemic infection associated with injection of living bacteria. Lastly, we compared hemocytes from mosquitoes at 24 hours and 19 days after ingestion of a blood meal infected with Plasmodium berghei to mosquitoes of the same age fed a non-infected blood meal to determine the ookinete and sporozoite infection responsive transcriptomes, respectively. This design resulted in a total of five experimental treatments. The following samples are not included in this submission: Hemo E coli vs. hemo unchallenged A Hemo E coli vs. hemo unchallenged B Hemo m luteus vs. hemo unchallenged A Hemo m luteus vs. hemo unchallenged B
Project description:Insect hemocytes mediate important cellular immune responses including phagocytosis and encapsulation, and also secrete immune factors such as opsonins, melanization factors, and antimicrobial peptides. In Anopheles, they contribute to the defense against malaria parasite invasion during the early sporogonic cycle. We used microarrays to identify transcripts that are specific or enriched in circulating hemocytes compared to either neuronal or to the rest of the body.
Project description:Anopheles gambiae mosquitoes transmit the human malaria parasite Plasmodium falciparum, which causes the majority of fatal malaria cases worldwide. The hematophagous life style defines the mosquito reproductive biology and is exploited by P. falciparum for its own sexual reproduction and transmission. The two main phases of the mosquito reproductive cycle, pre-vitellogenic (PV) and post-blood meal (PBM) shape its capacity to transmit malaria. Transition between these phases is tightly coordinated to ensure homeostasis between mosquito tissues and successful reproduction. One layer of control is provided by microRNAs, well-known regulators of blood meal digestion and egg development in mosquitoes. Here, we report a global overview of tissue-specific miRNA expression during the PV and PBM phases and identify miRNAs regulated during PV to PBM transition. The observed coordinated changes in the expression levels of a set of miRNAs in the energy-storing tissues suggest a role in the regulation of blood meal-induced metabolic changes.
Project description:Insect hemocytes mediate important cellular immune responses including phagocytosis and encapsulation, and also secrete immune factors such as opsonins, melanization factors, and antimicrobial peptides. In Anopheles, they contribute to the defense against malaria parasite invasion during the early sporogonic cycle. We used microarrays to identify transcripts that are specific or enriched in circulating hemocytes compared to either neuronal or to the rest of the body. Hemocytes, heads and carcasses were isolated from naïve adult females 1-2 days after eclosion.
Project description:Transmission of malaria is dependent on the successful completion of the Plasmodium lifecycle in the Anopheles vector. Major obstacles are encountered in the midgut tissue, where most parasites are killed by the mosquito’s immune system. In the present study, DNA microarray analyses have been used to compare Anopheles gambiae responses to invasion of the midgut epithelium by the ookinete stage of the human pathogen Plasmodium falciparum and the rodent experimental model pathogen P. berghei. Invasion by P. berghei had a more profound impact on the mosquito transcriptome, including a variety of functional gene classes, while P. falciparum elicited a broader immune response at the gene transcript level. Ingestion of human malaria-infected blood lacking invasive ookinetes also induced a variety of immune genes, including several anti-Plasmodium factors. Keywords: Anopheles gambiae, Plasmodium falciparum, ookinete, invasion, innate immunity
Project description:We characterize the epigenome of the human malaria vector Anopheles gambiae in midgut cells by mapping the distribution and levels of two post-translational histone modifications, H3K27ac and H3K27me3. These histone profiles were then correlated with levels of gene expression obtained by RNA-seq.