Insulin, IGF and Insulin Signaling: effects on Anopheles lifespan and immunity

描述(申请人提供)：药物和农药抗药性的增加使许多蚊媒疾病的控制计划变得无用，因此迫切需要新的控制策略。疟疾寄生虫必须在蚊子体内生长长达两周，从概念上讲，可以通过提高蚊子的先天免疫力或缩短蚊子的寿命来破坏这种发育。胰岛素/胰岛素样生长因子-1信号级联(ISC)调节线虫和果蝇的先天免疫和寿命，因此可以被操纵来降低蚊子的媒介能力。根据我们的初步数据，血粉中的外源性胰岛素不仅调节雌性蚊子的寿命和氧化应激反应，而且还调节疟原虫的发育。为了进一步阐明这些有希望的结果，我们将首先确定外源性人胰岛素和IGF-1是否可以刺激斯氏按蚊中肠和其他组织(如脂肪体)的ISC。我们还将测试这些因素对氧化应激和一氧化氮产生、衰老的关键成分、先天免疫和信号的影响。接下来，我们将设计一个。斯氏蚊子在血餐后在中肠表达两种ISC蛋白的活性形式，Akt和PTEN。由于AKT激活中肠ISC，而PTEN具有相反的作用，我们将能够回答三个问题：(1)中肠ISC是否调节氧化应激，进而调节AN的衰老和先天免疫。Stephensi？(2)中肠ISC是否影响其他AN中的信号。斯芬西纸巾？(3)ISC的改变对恶性疟原虫的发育有何影响。斯特芬西？最后，我们将检查外源性人胰岛素和IGF-1的生理水平对上述转基因蚊子的影响。人类血液中的胰岛素水平在用餐后和疟疾寄生虫感染期间可能会变化多达10倍。通过了解人类血粉中这种自然发生的变化的影响，我们可以更好地预测Akt和PTEN过度表达对媒介能力的关键变量(如寿命和免疫力)的影响。总而言之，我们拟议的工作将测试关于ISC及其对蚊子生理和媒介能力的影响的基本和应用假设，这些假设是为模型无脊椎动物和哺乳动物概念化的。此外，我们的工作提供了一种不同的方法来对蚊子进行转基因修饰，以限制它们的媒介能力。与公共卫生相关在被摄入血粉后，疟疾寄生虫、病毒和线虫必须在蚊子体内长时间滋生，然后才能传播给人类和宿主。我们的目标是提高先天免疫力或缩短模型蚊子的寿命，以防止病原体发育完成，从而减少或消除传播。

DESCRIPTION (provided by applicant): Increased drug and pesticide resistance has rendered many control programs for mosquito-borne diseases useless, resulting in an urgent need for new control strategies. Malaria parasites must develop for up to two weeks in the mosquito, and conceptually, this development can be disrupted by enhancing mosquito innate immunity or by shortening the mosquito's lifespan. The insulin/IGF-1 signaling cascade (ISC) regulates both innate immunity and lifespan in Caenorhabditis elegans and Drosophila melanogaster, and, thus, could be manipulated to reduce vector competence of mosquitoes. Based on our preliminary data, exogenous insulin in the bloodmeal modulates not only lifespan and oxidative stress response in female mosquitoes, but also Plasmodium development. To further elucidate these promising results, we will first determine whether exogenous human insulin and IGF-1 can stimulate the ISC in the midgut and other tissues, such as the fat body, in the mosquito Anopheles stephensi. We will also test the impact of these factors on oxidative stress and NO production, key components of aging, innate immunity, and signaling. Next we will engineer An. stephensi mosquitoes to express active forms of two ISC proteins, Akt and PTEN, in the midgut after a bloodmeal. Because AKT activates the midgut ISC and PTEN has the opposite effect, we will be able to answer three questions: (1) Does the midgut ISC regulate oxidative stress and in turn aging and innate immunity in An. stephensi? (2) Does the midgut ISC affect signaling in other An. stephensi tissues? And (3) How do changes to the ISC affect Plasmodium falciparum development in An. stephensi? Finally, we will examine the impact of physiological levels of exogenous human insulin and IGF-1 on the transgenic mosquitoes described above. Insulin levels in human blood can vary by as much as 10-fold after a meal and during malaria parasite infection. By understanding the effects of this naturally occurring variation in human bloodmeals, we can better predict the efficacy of Akt and PTEN over expression on critical variables (e.g., lifespan and immunity) of vector competence. In summary, our proposed work will test both basic and applied hypotheses regarding the ISC and its impacts on mosquito physiology and vector competence that were conceptualized for model invertebrates and mammals. In addition, our work offers a different approach to the transgenic modification of mosquitoes to limit their vectorial capacity. PUBLIC HEALTH RELEVANCE After being ingested in a bloodmeal, malaria parasites, viruses, and nematodes must develop in mosquitoes for extended periods before being transmitted to humans and reservoir hosts. Our goal is to enhance innate immunity or reduce the lifespan of a model mosquito to prevent completion of pathogen development, so that transmission is reduced or eliminated.