Heparin-mimetic sulfated oligoxylan inhibitors of malaria parasites

疟疾寄生虫的肝素模拟硫酸化寡聚木聚糖抑制剂

• 批准号: 7734763
• 负责人: AUDREY L STONE
• 金额: $ 1.02万
• 依托单位: EUNICE KENNEDY SHRIVER NATIONAL INSTITUTE OF CHILD HEALTH & HUMAN DEVELOPMENT
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7734763
• 关键词: Acute; Anabolism; Animal Model; Anti-HIV Agents; Anti-malarial drug resistance; Anticoagulants; Antimalarials; Biological; Biological Assay; Biopolymers; CD4 Positive T Lymphocytes; CYP1A1 gene; Calculi; Cerebral Malaria; Cessation of life; Charge; Child; Class; Clinical; Clinical Research; Culicidae; Data; Development; Disease; Dose; Endothelium; Enzymes; Erythrocytes; Exhibits; Family; Glucuronic Acid; Glucuronic Acids; Goals; HIV Infections; HIV-1; Health Sciences; Heparin; Heparitin Sulfate; Hepatocyte; Human; Immunity; In Vitro; Incidence; Infection; Inorganic Sulfates; Invaded; Libraries; Life; Malaria; Malaria Vaccines; Medical; Microcirculation; Molecular; Oligosaccharides; Organism; Parasites; Pathology; Patients; Pharmaceutical Preparations; Physiological; Plasmodium falciparum; Preparation; Preventive; Process; Production; Protein Isoforms; Range; Rate; Reaction; Resistance; Role; Specificity; Sporozoites; Staging; Structure; Symptoms; System; Testing; Thinking; Thrombin; Tissues; United States National Institutes of Health; Unspecified or Sulfate Ion Sulfates; Vaccines; Variant; Virulent; Xylans; Xylose; base; combinatorial; density; drug development; in vivo; inhibitor/antagonist; mimetics; mimicry; novel; pathogen; prevent; programs; receptor; sugar

The initial infective process of the malaria parasite in humans is between the invading parasite and hepatocytes of the host. In several studies, the portal for this invasion has implicated the heparin/heparan sulfate (H/HS) receptor systems (which we classified early on to be in a sepatate class of glycocaminoglycan biopolymers on the basis of the specificity of their optically active structures (AL Stone 1963/4 Biopolymers 2/3). Heparin also inhibits the rosetting and cytoadhesion of parasitized Plasmodium falciparum erythrocytes (PfRBC) to normal RBC and the endothelium, and to clear blockage of the microcirculation which ameliorates life-threatening symptoms of cerebral malaria when administered in children. H/HS are modulatory receptors. They are found in most tissues of the body where they not only govern the level of activity/function of numerous normal physiological systems, but they also seem to serve as receptors for various human pathogens in a mechanism(s) that needs further elucidation. Malaria ranks in the top three deadliest diseases globally (more than 300 million clinical cases per year). 1-3% of the Pf parasites are highly virulent, causing severe and cerebral malaria and the death of about 2 million people per year (90 % young children). There is no preventive vaccine, and malarial parasites are increasingly resistant to anti-malarial drugs. We have applied our library of heparin-mimetic S-oligoS produced for development of heparin-based anti-HIV drugs (see HD 001315 -14) to characterize the inhibition of the malaria parasites by heparin in vitro and explore its potential usefulness as an anti-malarial. This enabled us to find that the heparin-based inhibition of P. yoelii sporozoites (freshly isolated from infected mosquitos) to invade an hepatocyte was governed by a degree of structural specificity and concentration dependent; highest potency resided in two S-OligoS in mass class about 7200 (Cp6) and 3700 (C11) displaying 43 and 56 percent inhibition at 3.5 and 5 micromolar, resp. S-oligoS of 3700 mass have shown negligible anti-thrombin capacity. Additional Cp11 for continuing studies is in preparation. In contrast to sporozoite invasion of hepatocytes, the structure-function relation of S-oligoS library components in the erythrocyte invasion stage of malarial parasites revealed that components of mass class less than 4500 exhibited very low inhibitory capacity, while high potency was associated only with relatively high mass class equal to or greater than 10,000. Such data suggests that the molecular reactions underlying the inhibition of the two parasite stages differ. Preparation of additional Cp11 and expansion of our library of components in the mass range about 4-3000 is continuing as will the resumption of studies on inhibition of sporozoites, parasitized RBC, and rosetting as a path towards stable, inexpensive heparin-based anti-malarials against initial infection, pathologies, and/or acute cerebral malaria. LJAburadad, et al (Science319:1603 2006) recently developed a statistical analysis wich they used to calculate relaible estimate of the previously "anecdotal" findings that HIV infection in malaria endemic regions is spread at a rate 8 percent higher than in other regions where HIVAIDS is on the rise, and vise-versa, due to an unexplained vulnerability of either patient to the second pathogen. Previously, our results had led us to suggest that co-treatment of malaria and HIV-AIDS would be feasible because of the close similarity in the physicochemical proerties of the respective S-oligoS inhibitors. Now, a preliminary study of the effect of co-dosing SOLIS with increasing proportions of Cp11 on the capacity of SOLIS to inhibit the cytopathic action of HIV-1 on CD4 cells in vitro is completed. Results suggest that the presence of the anti-malarial S-oligoS diminished the inhibutory effect of SOLIS in vitro. This effect is not readily predictive for an in vivo system because the mechanism of thr process is not fully understood. We think the inhibition of inhibitory capacity of our anti-HIV drug in vitro may be a reflection of a common mechanism for the biological production of the endogenous H/HS receptors for malaria and HIV-1, such as the mechanisms of specific expression of specific enzyme isoforms in the biosynthesis of anticoagulant H/HS (revealed and elucidated by Robert D. Rosenthal and coworkers in the previous decade). Continuation of the basic as well as practical studies on this inter-pathogen effect on disease and anti-pathogen will use, if feasible, an animal model such as that offered in an NIH intrmural program. CURRENT STUCTURAL CONSIDERATIONS indicate the S-OligoS structure contains a tetrasaccharide motif of three xyloses and a glucuronic acid as a branch on the xylan chain i.e., -D-glucuronyl-alpha 1,2 beta 1,4 D-(xylyl)3 with up to one third of the GlcA O-methylated. The sugars are within 90 percent sulfated yielding a high negative charge density. Such motif could accommodate the subtle variations in geometries involving sulfates which would be components to provide for mutifunctional mimicry of the heparins.

人类疟原虫寄生虫的最初感染过程在宿主的入侵寄生虫和肝细胞之间。 在几项研究中，该入侵的门户涉及肝素/肝素硫酸盐（H/HS）受体系统（我们很早就对其分类为在隔离的糖胺聚糖生物聚合物类别中，基于其光学活性结构的特异性（Al Stone 1963/4 Bioparymiss and Cytan）。恶性疟原虫的红细胞（PFRBC）到正常的RBC和内皮，并清除微循环的阻塞，以减轻脑疟疾的症状，当时它们在大多数人的身体中都可以统治它们。作为各种人类病原体的受体，需要进一步阐明疟疾。没有预防性疫苗，疟疾寄生虫越来越对抗疟疾药物具有抗性。 我们已经应用了产生的肝素模拟S-橄榄岩库来开发基于肝素的抗HIV药物（请参阅HD 001315 -14），以表征肝素在体外对疟疾寄生虫的抑制，并探索其潜在的有用性作为抗疫苗。这使我们能够发现基于肝素基于肝素的孢子菌（从感染蚊子新鲜分离）的抑制作用以一定程度的结构特异性和浓度依赖于肝细胞。在大约7200（CP6）和3700（C11）的质量类别中，最高效力在3.5和5 microlol，分别为43％和56％的抑制作用中。 3700质量的S-Oligos显示出可忽略的抗脑栓塞能力。 持续研究的其他CP11正在准备。 与肝细胞的孢子虫入侵相反，在疟原虫寄生虫的红细胞入侵阶段S-Oligos库组件的结构功能关系显示，质量类别小于4500的质量类别的抑制能力非常低，而高效力仅与质量较高的质量级别相等，而高于质量较高的质量相等或更大。这样的数据表明，抑制两个寄生虫阶段的分子反应不同。 准备额外的CP11和我们在质量范围内的组件图书馆的扩展范围约为4-3000，这将继续进行，恢复有关孢子虫的抑制作用，寄生的RBC的研究以及玫瑰花含量，作为稳定的，廉价的基于肝素的抗甲型抗乳腺癌的途径。 Ljaburadad等人（Science319：1603 2006）最近制定了一种统计分析，他们用来计算以前“轶事”发现的可靠估计值，即疟疾中流区域的HIV感染的速度分布在8％的速度上，而Hivaids的其他地区则高于其他患者，并且患者的病情相比，该地区的患者是偶然的。以前，我们的结果促使我们提出，由于相应的S-Oligos抑制剂的物理化学方面的相似性非常相似，因此对疟疾和HIV-AID的共同治疗是可行的。 现在，对CP11的共同剂量SOLIS的影响的初步研究对SOLIS抑制HIV-1在体外抑制CD4细胞的细胞病变作用的能力的影响已完成。 结果表明，抗疟疾的S-橄榄岩的存在减少了Solis在体外的抑制作用。这种效果对体内系统不容易预测，因为THR过程的机制尚未完全理解。 我们认为，体外抗HIV药物抑制能力的抑制作用可能反映了内源性H/HS受体生物产生疟疾和HIV-1的常见机制，例如特定酶同工型的特定表达的机制 在抗凝H/HS的生物合成中（在过去的十年中，Robert D. Rosenthal和同事揭示和阐明）。 继续对这种对疾病和抗病原体影响的基本和实践研究的延续（如果可行的话），则可以使用NIH内部计划中提供的动物模型。 当前的构件考虑表明，S-Oligos结构包含三种木糖和葡萄糖酸的四含糖基序，作为Xylan链上的分支，即-D-葡萄糖酰基-Alpha 1,2β1,2β1,4d-（Xylyl）3，最多三分之一的GlCA O-My-甲基化的三分之一。糖在90％的硫酸盐之内，产生高电荷密度。 这种基序可以适应涉及硫酸盐的几何形状的细微变化，这些变化将是提供肝素型模仿的组成部分。