Ranjan Amalendu P, Czyzyk Daniel J, Martinez-Traverso Griselle, Sadiqova Aygul, Valhondo Margarita, Schaefer Deborah A, Spasov Krasimir A, Jorgensen William L, Vishwanatha Jamboor K, Riggs Michael W, Castellanos-Gonzalez Alejandro, Anderson Karen S
Department of Microbiology, Immunology and Genetics, College of Biomedical and Translational Sciences, University of North Texas Health Science Center Fort Worth TX 76107 USA
Department of Pharmacology, Yale University School of Medicine 333 Cedar Street New Haven CT 06520 USA
RSC Pharm. 2024 Sep 19;1(5):963-975. doi: 10.1039/d4pm00093e. eCollection 2024 Dec 10.
The gastrointestinal disease cryptosporidiosis, caused by the genus , is a common cause of diarrheal diseases in children, particularly in developing countries and frequently fatal in immunocompromised individuals. ()-specific bifunctional dihydrofolate reductase-thymidylate synthase (DHFR-TS) has been a molecular target for inhibitor design. (.) While nanomolar inhibitors of DHFR-TS have been identified at the biochemical level, effective delivery of these compounds to achieve anticryptosporidial activity in cell culture and models of parasite infection remains a major challenge in developing new therapies. Previous studies, using a nanotherapy approach, have shown a promising DHFR-TS inhibitor, 906, that can successfully target parasites in cell culture with nanomolar anticryptosporidial activity. This formulation utilized poly(lactic--glycolic acid) (PLGA) nanoparticles (NPs) loaded with 906 (NP-906) and conjugated with a monoclonal antibody (MAb) on the nanoparticle surface to specifically target the glycoprotein GP25-200 in excysting oocysts. However, a limitation for use is antibody susceptibility to gastric acidity. To address this gap, a prodrug diethyl ester form of 906 (MAb-NP-Prodrug) was synthesized that allowed higher compound loading in the MAb-coated PLGA nanoparticles. An oral formulation was prepared by loading lyophilized MAb-NP-Prodrug into gelatin capsules with an enteric coating for gastric stability. Proof-of-concept studies with this oral formulation demonstrated antiparasitic activity in a chronic mouse model of infection. Efficacy was observed after a low daily dose of 2 × 8 mg kg for 5 days, when examined 6 and 20 days postinfection, offering a new avenue of drug delivery to be further explored.
由隐孢子虫属引起的胃肠道疾病隐孢子虫病，是儿童腹泻病的常见病因，在发展中国家尤为常见，在免疫功能低下的个体中往往是致命的。隐孢子虫特异性双功能二氢叶酸还原酶-胸苷酸合成酶（DHFR-TS）一直是抑制剂设计的分子靶点。虽然在生化水平上已鉴定出纳摩尔级的DHFR-TS抑制剂，但在细胞培养和寄生虫感染模型中有效递送这些化合物以实现抗隐孢子虫活性，仍然是开发新疗法的一项重大挑战。以前的研究采用纳米疗法，已显示出一种有前景的DHFR-TS抑制剂906，它能够在细胞培养中以纳摩尔级抗隐孢子虫活性成功靶向隐孢子虫寄生虫。该制剂使用负载有906的聚乳酸-乙醇酸共聚物（PLGA）纳米颗粒（NP-906），并在纳米颗粒表面与单克隆抗体（MAb）偶联，以特异性靶向脱囊卵囊中的糖蛋白GP25-200。然而，隐孢子虫使用的一个限制是抗体对胃酸敏感。为了弥补这一差距，合成了906的前药二乙酯形式（MAb-NP-前药），这使得在MAb包被的PLGA纳米颗粒中能够更高地负载化合物。通过将冻干的MAb-NP-前药装入具有肠溶包衣以保持胃稳定性的明胶胶囊中制备口服制剂。对该口服制剂的概念验证研究在隐孢子虫感染的慢性小鼠模型中证明了抗寄生虫活性。当在感染后6天和20天进行检查时，每天低剂量2×8mg/kg持续5天观察到了疗效，为进一步探索新的药物递送途径提供了依据。
