Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, USA.
Department of Biological Sciences, Columbia University, New York, NY, USA.
Malar J. 2024 Aug 1;23(1):227. doi: 10.1186/s12936-024-05056-0.
BACKGROUND: Plasmodium falciparum, the malaria-causing parasite, is a leading cause of infection-induced deaths worldwide. The preferred treatment approach is artemisinin-based combination therapy, which couples fast-acting artemisinin derivatives with longer-acting drugs, such as lumefantrine, mefloquine, and amodiaquine. However, the urgency for new treatments has risen due to the parasite's growing resistance to existing therapies. In this study, a common characteristic of the P. falciparum proteome-stretches of poly-lysine residues, such as those found in proteins related to adhesion and pathogenicity-is investigated for its potential to treat infected erythrocytes. METHODS: This study utilizes in vitro culturing of intra-erythrocytic P. falciparum to assess the ability of poly-lysine peptides to inhibit the parasite's growth, measured via flow cytometry of acridine orange-stained infected erythrocytes. The inhibitory effect of many poly-lysine lengths and modifications were tested this way. Affinity pull-downs and mass spectrometry were performed to identify the proteins interacting with these poly-lysines. RESULTS: A single dose of these poly-basic peptides can successfully diminish parasitemia in human erythrocytes in vitro with minimal toxicity. The effectiveness of the treatment correlates with the length of the poly-lysine peptide, with 30 lysine peptides supporting the eradication of erythrocytic parasites within 72 h. PEG-ylation of the poly-lysine peptides or utilizing poly-lysine dendrimers and polymers retains or increases parasite clearance efficiency and bolsters the stability of these potential new therapeutics. Lastly, affinity pull-downs and mass-spectrometry identify P. falciparum's outer membrane proteins as likely targets for polybasic peptide medications. CONCLUSION: Since poly-lysine dendrimers are already FDA-approved for drug delivery and this study displays their potency against intraerythrocytic P. falciparum, their adaptation as anti-malarial drugs presents a promising new therapeutic strategy for malaria.
背景:疟原虫是引起疟疾的寄生虫,是全球感染致死的主要原因。首选的治疗方法是青蒿素为基础的联合疗法,它将快速作用的青蒿素衍生物与长效药物(如青蒿琥酯、甲氟喹和阿莫地喹)结合使用。然而,由于寄生虫对现有疗法的耐药性不断增强,对新疗法的迫切需求也在增加。在这项研究中,研究了疟原虫蛋白质组的一个共同特征——多赖氨酸残基,如与粘附和致病性相关的蛋白质中的多赖氨酸残基,以研究其治疗感染红细胞的潜力。
方法:本研究利用体外培养的疟原虫感染红细胞,通过吖啶橙染色感染红细胞的流式细胞术评估多聚赖氨酸肽抑制寄生虫生长的能力。通过这种方法测试了许多不同长度和修饰的多聚赖氨酸的抑制效果。进行亲和下拉和质谱分析以鉴定与这些多聚赖氨酸相互作用的蛋白质。
结果:这些多碱性肽的单次剂量可成功减少体外人红细胞中的疟原虫血症,且毒性最小。治疗效果与多聚赖氨酸肽的长度相关,30 个赖氨酸肽可在 72 小时内消除红细胞寄生虫。聚乙二醇化多聚赖氨酸肽或使用多聚赖氨酸树突和聚合物保留或增加寄生虫清除效率,并增强这些潜在新疗法的稳定性。最后,亲和下拉和质谱分析鉴定出疟原虫的外膜蛋白可能是多碱性肽药物的靶标。
结论:由于多聚赖氨酸树突已被 FDA 批准用于药物递送,本研究显示其对红细胞内疟原虫的效力,因此将其作为抗疟药物具有很大的潜力,为疟疾提供了一种新的有前途的治疗策略。
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