Our work to date has focused on understanding how ingested mammalian transforming growth factor (TGF)-?1 is activated, regulates mosquito Smad signaling and endogenous TGF-?s, and ultimately reduces malaria parasite loads in A. stephensi. This work led to the study of signaling pathways by which this inter-species crosstalk occurs, guided by advances in the field of mammalian immunity and inflammation. In mammals, four interacting regulatory pathways are associated with immunity: the nuclear factor (NF)-?B pathway and the three mitogen-activated protein kinase (MAPK) pathways, including JNK, ERK and p38-dependent pathways. We have shown that TGF-?1 signaling in A. stephensi cells is regulated by redox chemistry and involves differential activation of the A. stephensi homologs of ERK, JNK, and p38. We have also identified other bloodmeal-derived factors including insulin, two parasite toxins, and two mammalian inflammatory mediators that, like TGF-?1, may function as signals to A. stephensi cells. Indeed, our preliminary data suggest that these factors also regulate the activation of A. stephensi ERK, JNK, and p38. Our long-term goal is to manipulate a highly complex ecological system--which consists of the mosquito host, the mammalian host, and the parasite--as a whole in order to block malaria infection. We hypothesize that a coordinated network of pathways (MAPKs, Smads, NF-?B) regulates the mosquito response to infection. Moreover, the inflammatory outcomes driven by these signaling pathways set in motion new signals that must be interpreted by all three members of this ecosystem. This challenge is daunting, given the complexity of the inflammatory response in a single species. Yet, we have shown that this complexity can be addressed rationally through inter-connected experimental approaches and computational simulations. As such, we will leverage our experience with this system and with computational simulations of inflammation at multiple scales, from the intracellular level to the multi-organismal level, including preliminary models of inter-species crosstalk in the setting of malaria. We propose that this integrated approach will allow us to discern not only the mechanisms operant in the process of immune crosstalk, but also explain unexpected behavior in the system and define the """"""""master switches"""""""" - the crosstalking extracellular factors and signaling pathway components - that have the greatest potential impact on parasite development in A. stephensi.
The mosquito Anopheles stephensi is an important vector of the human malaria parasite Plasmodium falciparum. Many studies have focused on individual gene products that respond to and destroy these parasites, but there is little to no information on the coordinated regulation of these responses. Our studies will elucidate this coordination and develop mathematical and statistical models of the biological interface of the mosquito, the parasite, and the mammalian host. These studies will serve to identify the master switches that control parasite development in the mosquito. In the long-term, we propose that this information will contribute to novel malaria control methods.
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