Amphotericin B Nanodisks and Cryptococcal Meningits

描述（由申请人提供）：我们研究的长期目标是改善患有全身性真菌感染的个体的治疗选择。艾滋病毒感染者感染机会性真菌的风险增加，目前的治疗方案不是最佳的。新型隐球菌感染是一个严重的问题，可导致潜在的致命疾病——隐球菌性脑膜炎。抗生素两性霉素B （ampB）对新生梭状芽孢杆菌有活性，但严重的副作用限制了其使用。同样，这种不溶性抗生素的脂质配方减少了药物的毒副作用，允许更高的剂量给药。目前，FDA批准了三种不同的ampB脂质制剂用于治疗对标准ampB脱氧胆酸盐（Fungizone）治疗难治性全身真菌感染。在研究一种独特的蛋白质家族——两亲载脂蛋白的脂质相互作用特性的过程中，我们发现了一种将ampB结合到离散的脂质蛋白颗粒（称为纳米盘）中的方法。ampB纳米圆盘的脂质质量高达30%为ampB，并以均匀的圆盘状颗粒的形式存在，其中含有ampB的磷脂双分子层被圆盘周围的载脂蛋白分子所包围。表征研究表明，ampB纳米磁盘是稳定的实体，可以在不损失结构完整性的情况下进行冻干和重组。对多种病原真菌的体外生长抑制实验表明，ampB-纳米盘对真菌生长的抑制率为90%，其浓度远低于AmBisome和ampB脂质体制剂。在本研究中，我们计划优化ampB-纳米盘的组成、结构和稳定性，评估与观察到的增强生物活性机制相关的假设，并确定ampB-纳米盘在隐球菌病动物模型中的体内功效。我们预计获得的结果将为艾滋病相关的隐球菌性脑膜炎提供新的治疗选择，提供优于现有治疗的优势。

DESCRIPTION (provided by applicant): The long-term goal of our research is to improve therapy options for individuals suffering from systemic fungal infections. HIV infected individuals are at increased risk for opportunistic fungal infection and current treatment regimens are not optimal. Infection with Cryptococcus neoformans represents a serious problem that results in the potentially fatal disease, cryptococcal meningitis. The antibiotic, amphotericin B (ampB) is active against C. neoformans but serious side effects limit its use. By the same token formulation of this insoluble antibiotic with lipids decreases toxic side effects of the drug, permitting higher doses to be administered. Currently, three different lipid formulations of ampB are approved by the FDA for treatment of systemic fungal infections that are refractory to standard ampB deoxycholate (Fungizone) therapy. During the course of studies of the lipid interaction properties of a unique family of proteins, the amphipathic apolipoproteins, we discovered a method to incorporate ampB into discrete, lipid protein particles, termed Nanodisks. AmpB-Nanodisks possess up to 30 % of their lipid mass as ampB and exist as a homogenous population of disk-shaped particles wherein a phospholipid bilayer containing the ampB is circumscribed by apolipoprotein molecules around the perimeter of the disk. Characterization studies revealed that ampB Nanodisks are stable entities and may be lyophilized and reconstituted without loss of structural integrity. In vitro growth inhibition assays with various pathogenic fungal species revealed that ampB-Nanodisks inhibit 90 % of fungal growth as concentrations far lower than the liposomal formulation of ampB, AmBisome. In the present proposal we plan to optimize the composition, structure, and stability of ampB- Nanodisks, evaluate hypotheses related to the mechanism of the observed enhanced biological activity and determine the in vivo efficacy of ampB-Nanodisks in an animal model of cryptococcosis. We anticipate the results obtained will lead to new treatment options for AIDS related cryptococcal meningitis that offer advantages over existing therapies.