Heparin/heparan Sulfate Mimetics: Modulators Of Malaria

肝素/硫酸乙酰肝素模拟物：疟疾调节剂

• 批准号: 7209193
• 负责人: AUDREY L STONE
• 金额: --
• 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/7209193
• 关键词: Plasmodium; antimalarial agents; biomimetics; drug design /synthesis /production; heparan sulfate; heparin; intracellular parasitism; liver cells; malaria; microorganism culture; parasite infection mechanism; parasitic liver disorder

We continued to investigate the development of therapeutic agents against the invasion and pathogenicity of the malaria parasite in the heparin/heparan sulfate (H/HS) family of oligo-and polysaccharides and their mimetic sulfated xylan oligosaccharides. Malaria ranks in the top three deadliest diseases globally, with ~300 million clinical cases per year. 1-3% of the Plasmodium falciparum (Pf) parasites are more virulent causing severe and cerebral malaria and the death of ~2 million people; 90 % are young children. There is no preventive vaccine, and malarial parasites are increasingly resistant to anti-malarial drugs. Heparin inhibits the invasion of hepatocytes (the initial infection) by Pf parasites; may be involved in the invasion of RBCs; inhibits the rosetting and cytoadhesion of parasitized RBC (PfRBC) to normal RBC and the endothelium (a cause of severe malaria); and heparin was found to clear blockage of the microcirculation in a study of cerebral malaria in children. We prepared a library of H/HS-mimetic S-oligoS from a heparin-mimetic pharmaceutical (comprised of a mixture of chemically-sulfated oligoxylans which mimics numerous discrete biological actions of the heparin family). We developed a macro combinatorial strategy that examines whether a given heparin function, like anti-coagulation, would be separable and governed by structural specificity within the family, and whether the active component would likely lack anti-thrombin capacity as well (first applied to the anti-HIV-1 capacity of heparin/S-oligoS [HD001315-03-07]). These two characteristics are required indicators of usefulness in further drug development. Our anti-malaria findings, which showed that S-oligoS inhibited hepatocyte invasion and was governed by structural specificity, are consistent with the known molecular glycobiology of H/HS in its multifunctional modulation of anti-thrombin in the clotting cascade. We expanded our H/HS-mimetic library to generate appropriate S-oligoS to continue the anti-malarial studies. Experiments for further collaboration on inhibition of parasite invasion of hepatocytes and RBCs in vitro have been planned, as well as studies on the inhibition of the rosetting of PfRBC in vitro. Research on this project is limited by delays in staffing. Work is near complete on an enlarged heparin-mimetic library to examine the capacity to inhibit rosetting in vitro and identify a potential therapeutic agent for use against acute cerebral malaria. Additional experiments will elucidate the H/HS-mimetic ligands by a modified gel-shift analysis of heparin oligoS-protein binding, and the testing of possible protein ligands using fluorescent (monodansylated) receptors (library S-oligoS and/or heparin-oligoS).

我们继续研究肝素/硫酸肝素（H/HS）寡糖 - 多糖及其模拟硫化的二甲烷寡糖的疟原虫毒性的侵袭和致病性。疟疾在全球排名前三的最致命疾病中排名，每年约有3亿个临床病例。 1-3％的恶性疟原虫（PF）寄生虫更具毒性，导致严重和脑疟疾，约200万人死亡； 90％是幼儿。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。肝素抑制PF寄生虫侵袭肝细胞（初始感染）；可能参与了RBC的入侵；抑制寄生的RBC（PFRBC）对正常RBC和内皮（严重疟疾的原因）抑制玫瑰花粘连和细胞粘附；在一项儿童脑疟疾研究中，发现肝素清除了微循环的阻塞。我们准备了来自肝素模拟药物的H/HS模拟S-橄榄石（由化学硫化的寡氧基组成的混合物组成，它们模仿了肝素家族的许多离散生物学作用）。我们制定了一种宏观组合策略，该策略检查给定的肝素功能（例如抗凝凝）是否可以分离并受家庭内部结构特异性的控制，以及活性成分是否也可能缺乏抗凝血酶的能力（首先应用于肝素/S-橄榄蛋白的抗HIV-HIV-HIV-HIV-HIV-HIV-HIV-HIV-HIV-HIV-HIV-HIV-HIV-HIV-HIV-HIV-HIV-HIV-HD001315-03-03-03-03-03-07]）。这两个特征是进一步的药物开发中有用的指标。 我们的抗马拉里菌发现表明，S-橄榄石抑制了肝细胞侵袭并受结构特异性的控制，与H/HS的已知分子糖生物学在其在凝乳级联中的抗凝血素的多功能调节中是一致的。我们扩展了H/HS模拟文库，以生成适当的S-Oligos，以继续进行反疟疾研究。已经计划在体外进行进一步合作，以进一步合作抑制肝细胞和RBCS的寄生虫入侵，以及研究抑制PFRBC体外玫瑰花质的研究。该项目的研究受到人员配备的延迟的限制。在扩大的肝素模拟文库上，工作几乎完成了，以检查体外抑制玫瑰花质的能力，并确定潜在的治疗剂，以抗急性脑疟疾。其他实验将通过对肝素寡聚蛋白结合的改良凝胶递移分析来阐明H/HS模拟配体，并使用荧光（单二酰化）受体（库S-橄榄核和/或/或肝素 - 橄榄石）对可能的蛋白质配体进行测试。