Leishmaniasis treatment: Macrophage scavenger receptor

描述（由申请人提供）：我们研究的长期目标是将载脂蛋白的独特结构特征和脂质相互作用特性应用于治疗利什曼病。载脂蛋白具有将磷脂囊泡转化为离散的、纳米尺度的、盘状复合物的能力，称为纳米盘（ND）。迄今为止的研究表明，将特异性疏水性药物分子掺入ND是可行的。载有多烯抗生素阿替霉素B（ampB）的ND在体外有效地抑制真菌生长。此外，在感染大型利什曼原虫的小鼠中的体内实验已经揭示ampB-ND在无毒剂量下显示功效。为了研究该效应的分子基础，将进行药代动力学研究，以确定作为ND给药的ampB的血浆衰减动力学和组织分布。ND的载脂蛋白组分将经历化学和/或遗传改变以产生被巨噬细胞上的A类清道夫受体（SR-A）识别的分子。将对ND的载脂蛋白组分进行定点诱变，以去除特定的带正电荷的残基，并定位带负电荷的氨基酸残基，使其产生SR-A的识别位点。转染SR-A的中国仓鼠卵巢细胞将用于设计用于测量工程化载脂蛋白的SR-A结合活性的结合实验。将在利什曼病小鼠模型中评价含有靶向SR-A的载脂蛋白组分的ampB-ND的疗效。将进行研究以检查通过将ampB与第二种疏水性抗利什曼病药物十六烷基磷酸胆碱合并到ND中所实现的潜在增强。ampB-ND在携带L.将评估major，并确定ampB-ND暴露对人外周血单核细胞的T细胞/细胞因子应答的影响。这些实验的结果应提供新的机会，治疗利什曼病，提供进一步深入了解SR-A的配体识别特性，并记录ND作为疏水性药物靶向递送载体的效用。

DESCRIPTION (provided by applicant): The long-term goal of our research is to apply the unique structural features and lipid interaction properties of apolipoproteins to the treatment of leishmaniasis. Apolipoproteins possess the capacity to transform phospholipid vesicles into discrete, nanometer scale, disc-shaped, complexes termed nanodisks (ND). Studies to date have shown that incorporation of specific hydrophobic drug molecules into ND is feasible. ND loaded with the polyene antibiotic amphotericin B (ampB) effectively inhibits fungal growth in vitro. Furthermore, in vivo experiments in Leishmania major infected mice have revealed that ampB-ND show efficacy at non-toxic doses. To investigate the molecular basis of this effect, pharmacokinetic studies will be performed to determine plasma decay kinetics and tissue distribution of ampB administered as ND. The apolipoprotein component of ND will be subject to chemical and/or genetic alteration to create a molecule that is recognized by the class A scavenger receptor (SR-A) on macrophages. Site-directed mutagenesis of the apolipoprotein component of ND will be performed to remove specific positively charged residues and position negatively charged amino acid residues such that they create a recognition site for SR-A. Chinese hamster ovary cells transfected with SR-A will be employed in binding experiments designed to measure the SR-A binding activity of engineered apolipoproteins. The efficacy of ampB-ND harboring apolipoprotein components targeted to SR-A will be evaluated in a mouse model of leishmaniasis. Studies will be performed to examine the potential enhancement achieved by incorporating ampB with a second hydrophobic anti-leishmanial drug, hexadecylphosphocholine, into ND. The extent to which ampB-ND induce parasite destruction in cells that harbor L. major will be assessed and the effect of ampB-ND exposure on the T cell/cytokine response of human peripheral blood mononuclear cells determined. The results of these experiments should offer new opportunity for the treatment of leishmaniasis, provide further insight into the ligand recognition characteristics of SR-A, and document the utility of ND as vehicles for targeted delivery of hydrophobic drugs.