Malaria sporozoite antigen‐directed genome‐wide response in transgenic Drosophila

Abstract

Malaria kills a million people annually. Understanding the relationship between a causative parasite, Plasmodium falciparum, and the mosquito vector might suggest novel prevention approaches. We created and transformed into Drosophila two genes encoding, thrombospondin-related adhesive protein (TRAP) and circumsporozoite protein (CSP), found on the cell surface of Plasmodium sporozoites. To understand a model insect's response, we induced these proteins separately and together, performing whole genome microarray analysis measuring gene expression changes. Gene ontology classification of responding genes reveals that TRAP and CSP strongly and differentially influence Drosophila genes involved with cell motility and gene regulation, respectively; however, the most striking effects are on the immune system. While immune-related genes are but modestly elevated compared with responses to sepsis, there is a marked repression of the Toll pathway. This suggests: (1) how Plasmodium infection of the mosquito might use TRAP and CSP to modulate the host insect's physiology to promote sporozoite survival and transmission to man and (2) that approaches to elevate expression of the mosquito's Toll pathway might lead to novel methods of malaria prevention.

Inference of the Oxidative Stress Network in Anopheles stephensi upon Plasmodium Infection

“…A previous study has utilized the robustness of the Drosophila system to identify genes that regulate Plasmodium growth in the mosquito [56] . For our analysis, we utilized the dataset from E-MEXP-1859 which originally was a Drosophila dataset with Plasmodial genes knocked in to understand the function of two important Plasmodium invasion molecules [57] . The study used Drosophila , a model system, to understand the role of Plasmodial surface antigens in Plasmodium invasion.…”

A database for the analysis of immunity genes in Drosophila

“…One study found that in transgenic D. melanogaster with high levels of cell surface proteins of the Plasmodium sporozoites, the expression of immune related genes were affected, although the Toll pathway expression was repressed. 22 The PADMA database can help understand such results more clearly in the context of Drosophila immunity against natural pathogens and the pathogen's ability to suppress or evade host defense.…”

The Drosophila melanogaster host model

“…Mutant and transgenic Drosophila lines are readily available at stock centers and have been extensively used to probe the interactions between pathogens and the Drosophila host. Drosophila loss-of-function immune response gene mutants have been used to examine the roles of the genes in the response to infection with various pathogens [11, (16, 19, 40–43) and Table 2], and transgenic Drosophila have been used to monitor the activation of immune response pathways upon infection (44, 45) and to examine the effects of transgenically expressed pathogen proteins on the host (21, 26, 46). Microarray and proteomic platforms as well as RNA interference (RNAi) lines and libraries have been developed and used to perform genome-wide analyses of Drosophila responses, in whole animals (41, 47–56) and in the well-established Drosophila cell culture lines, Schneider-2 (S2, embryonic-derived phagocytic cell) and malignant blood neoplasm (mbn-2) (56–59).…”

“…Pathogen genes can be expressed ubiquitously (26) or in specific fly tissues such as the fat body (21), wings (263), and eyes (264) by placing the transgene under the control of tissue-specific promoters. This has facilitated the identification of host cell targets of Plasmodium sporozite proteins (26), anthrax lethal factor and edema factor (263, 265), pertussis toxin (266), HIV-1 viral protein U (21), and Epstein-Barr virus immediate-early protein BZLF1 (264) (Table 1). …”

“…One of these animal models, the genetically tractable fruit fly, Drosophila melanogaster ( Drosophila ), has been well established as a model for studying the host–pathogen interactions of bacterial (1–9), fungal (10–17) and viral pathogens, and prior to the sequencing of the mosquito genome and the subsequent development of genetic tools, the malaria parasite (23–26); the model has also been used to probe the host defense response to infection.…”