Pan Ke, Zeng Ao, Ruan Xiaodie, Mo Xinyu, Shen Bang, Zhao Junlong, Zhou Yanqin
Key Laboratory Preventive Veterinary of Hubei Province, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China.
Front Cell Infect Microbiol. 2025 Jun 24;15:1542122. doi: 10.3389/fcimb.2025.1542122. eCollection 2025.
(), an apicomplexan parasite, infects a wide range of warm-blooded animals and poses significant risks to human health. The fatty acid synthesis II (FASII) pathway in the apicoplast, which is the major source of fatty acids in parasites, is considered a potential drug target. The apicoplast also harbors some enzymes of central carbon metabolism, which are crucial for its survival, but their biological roles remain unclear. In this study, we focused on apicoplast-localized isocitrate dehydrogenase 1 (ICDH1) and deleted it using CRISPR-Cas9 technology. The mutant tachyzoites displayed markedly impaired growth kinetics, with further suppression under serum-deprived conditions. However, this deletion did not affect the viability or virulence of the mutant in mice. NADPH, a product of ICDH1-mediated decarboxylation of isocitrate, is an essential cofactor for fatty acid synthesis. Using ¹³C glucose as a metabolic carbon source, we showed that the mutant strains had reduced incorporation of glucose-derived carbons into medium-chain length fatty acids (C14:0 and C16:0). Additionally, the growth of the mutant was partially restored by supplementation with exogenous C14:0 and C16:0 fatty acids. These results indicate that ICDH1 deletion affects the FASII pathway and parasite growth. Consistent with previous studies, this study confirms that has metabolic flexibility in the apicoplast that allows it to acquire fatty acids through various pathways.
（）是一种顶复门寄生虫，可感染多种温血动物，对人类健康构成重大风险。顶质体中的脂肪酸合成II（FASII）途径是寄生虫脂肪酸的主要来源，被认为是一个潜在的药物靶点。顶质体还含有一些中心碳代谢酶，这些酶对其生存至关重要，但其生物学作用仍不清楚。在本研究中，我们聚焦于定位于顶质体的异柠檬酸脱氢酶1（ICDH1），并使用CRISPR-Cas9技术将其敲除。突变的速殖子生长动力学明显受损，在血清饥饿条件下进一步受到抑制。然而，这种缺失并不影响突变体在小鼠中的生存能力或毒力。NADPH是ICDH1介导的异柠檬酸脱羧反应的产物，是脂肪酸合成的必需辅因子。使用¹³C葡萄糖作为代谢碳源，我们发现突变菌株将葡萄糖衍生的碳掺入中链长度脂肪酸（C14:0和C16:0）的能力降低。此外，通过补充外源性C14:0和C16:0脂肪酸，突变体的生长得到部分恢复。这些结果表明，ICDH1缺失影响FASII途径和寄生虫生长。与先前的研究一致，本研究证实（此处原文括号中内容缺失，请补充完整后进行翻译，若此处原文就是括号表示未提及具体物种，则按照现有内容进行）在顶质体中具有代谢灵活性，使其能够通过多种途径获取脂肪酸。
