Intracellular transfer of cholesterol in mosquitoes

描述（由申请人提供）：我们的长期目标是阐明胆固醇代谢的基本方面之一：通过亲水性细胞基质递送疏水性胆固醇分子以及该过程的生理重要性。不能合成胆固醇使得昆虫高度依赖于参与细胞固醇易位的有效运输机制。我们一直在研究蚊子固醇载体蛋白-2（AeSCP-2）在细胞内胆固醇转移中的作用。具体的假设是，AeSCP-2是这一过程中的重要环节。该假设基于以下观察结果：沉默埃及伊蚊幼虫中的AeSCP-2表达导致体内胆固醇掺入减少和蚊子中的高死亡率。我们已经确定了几个AeSCP-2抑制剂（SCPI）通过高通量筛选的小化学库。使用新发现的抑制剂抑制AeSCP-2功能可抑制体内胆固醇摄取，并导致蚊子幼虫的高死亡率。SCPI是埃及伊蚊、冈比亚按蚊和尖音库蚊中有效的杀幼虫剂，表明固醇载体蛋白-2在不同蚊子物种中具有功能相似性。具体目的1：在细胞培养模型系统中确定AeSCP-2介导细胞内胆固醇的机制。我们将野生型和突变型AeSCP-2的存在和功能与培养细胞内的胆固醇摄取和胆固醇再分布相关联。具体目标2：在蚊子生物模型系统中，使用新发现的抑制剂和RNA干扰（RNAi）检查AeSCP-2在协调甾醇和胆固醇吸收中的作用。具体目标3：确定AeSCP-2基因的转录调控。AeSCP-2基因的表达与胆固醇吸收和再分布需求高的生理过程相关。通过AeSCP-2基因的研究，将确定在胆固醇代谢中协调生理事件的重要转录因子。这项研究的结果将产生深刻的信息，涉及固醇载体蛋白-2的功能，并将阐明基因的调控。研究结果还将验证针对胆固醇代谢的潜力，以制定控制蚊子数量的新策略。

DESCRIPTION (provided by applicant): Our long-term goal is to elucidate one of the fundamental aspects of cholesterol metabolism: delivery of the hydrophobic cholesterol molecule through the hydrophilic cellular matrix and the physiological importance of this process. The inability to synthesize cholesterol makes insects highly dependent on the efficient transport mechanisms involved in cellular sterol translocation. We have been investigating the role of a mosquito sterol carrier protein-2 (AeSCP-2) in intracellular cholesterol transfer. The specific hypothesis is that AeSCP-2 is a vital link in the process. This hypothesis is based on the observations that silencing AeSCP-2 expression in Aedes aegypti larvae results in decreased incorporation of cholesterol in vivo and a high mortality rate in mosquitoes. We have identified several AeSCP-2 inhibitors (SCPIs) via high throughput screening of a small chemical library. Inhibition of AeSCP-2 function using the newly discovered inhibitors suppresses cholesterol uptake in vivo and results in a high mortality rate in mosquito larvae. SCPIs are effective larvicides in Aedes aegypti, Anopheles gambiae and Culex pipiens, indicating that a sterol carrier protein-2 has functional similarity in different mosquito species. Specific aim 1: Determine the mechanism of AeSCP-2 mediated intracellular cholesterol in a cell culture model system. We will correlate the presence and the function of wild-type and mutated AeSCP-2 to cholesterol uptake and cholesterol redistribution within the cultured cells. Specific aim 2: Examine the roles of AeSCP-2 in coordinating the absorption of sterols and cholesterol using newly discovered inhibitors and RNA interference (RNAi) in a mosquito organism model system. Specific aim 3: Determine the transcriptional regulation of the AeSCP-2 gene. Expression of the AeSCP-2 gene is correlated with physiological processes in which the demand for cholesterol absorption and redistribution is high. Important transcription factors that coordinate physiological events in cholesterol metabolism will be identified through the study of the AeSCP-2 gene. Results from this study will yield insightful information involving the function of sterol carrier protein-2 and will shed light on the regulation of the gene. The results will also validate the potential of targeting cholesterol metabolism for the development of new strategies to control mosquito populations.