Amphotericin B Nanodisks and Cryptococcal Meningitis

描述（由申请人提供）：我们研究的长期目标是改善全身真菌感染患者的治疗选择。HIV感染者机会性真菌感染的风险增加，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，导致潜在的致命性疾病，隐球菌脑膜炎。抗生素阿替霉素B（ampB）对C有活性。但严重的副作用限制了它的使用。同样，这种不溶性抗生素与脂质的制剂降低了药物的毒副作用，允许给予更高的剂量。目前，三种不同的ampB脂质制剂已被FDA批准用于治疗标准ampB脱氧胆酸盐（Fungizone）疗法难治的全身性真菌感染。在一个独特的蛋白质家族，两亲性载脂蛋白的脂质相互作用特性的研究过程中，我们发现了一种方法，将ampB纳入离散的，脂质蛋白颗粒，称为纳米盘。AmpB-Nanodisks的脂质质量高达ampB的30%，并以均匀的盘状颗粒群存在，其中含有ampB的磷脂双层被盘周边的载脂蛋白分子包围。表征研究表明，ampB Nanodisks是稳定的实体，可以冻干和复溶，而不会损失结构完整性。用各种致病真菌物种进行的体外生长抑制试验显示，ampB-纳米盘抑制90%的真菌生长，浓度远低于ampB的脂质体制剂AmBisome。在本提案中，我们计划优化ampB-Nanodisks的组成、结构和稳定性，评估与观察到的增强生物活性的机制相关的假设，并确定ampB-Nanodisks在隐球菌病动物模型中的体内疗效。我们预计所获得的结果将导致新的治疗方案，艾滋病相关的隐球菌脑膜炎，提供优于现有的治疗方法。

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.