Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 12735 Twinbrook Parkway, Rm 2E20A, Rockville, MD, 20852, USA.
Department of Molecular Microbiology and Immunology, Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA.
Nat Commun. 2022 May 26;13(1):2949. doi: 10.1038/s41467-022-30606-y.
In mammals, the serine protease plasmin degrades extracellular proteins during blood clot removal, tissue remodeling, and cell migration. The zymogen plasminogen is activated into plasmin by two serine proteases: tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA), a process regulated by plasminogen activator inhibitor 1 (PAI-1), a serine protease inhibitor that specifically inhibits tPA and uPA. Plasmodium gametes and sporozoites use tPA and uPA to activate plasminogen and parasite-bound plasmin degrades extracellular matrices, facilitating parasite motility in the mosquito and the mammalian host. Furthermore, inhibition of plasminogen activation by PAI-1 strongly blocks infection in both hosts. To block parasite utilization of plasmin, we engineered Anopheles stephensi transgenic mosquitoes constitutively secreting human PAI-1 (huPAI-1) in the midgut lumen, in the saliva, or both. Mosquitoes expressing huPAI-1 strongly reduced rodent and human Plasmodium parasite transmission to mosquitoes, showing that co-opting plasmin for mosquito infection is a conserved mechanism among Plasmodium species. huPAI-1 expression in saliva induced salivary gland deformation which affects sporozoite invasion and P. berghei transmission to mice, resulting in significant levels of protection from malaria. Targeting the interaction of malaria parasites with the fibrinolytic system using genetically engineered mosquitoes could be developed as an intervention to control malaria transmission.
在哺乳动物中，丝氨酸蛋白酶纤溶酶在清除血栓、组织重塑和细胞迁移过程中降解细胞外蛋白。酶原纤溶酶原通过两种丝氨酸蛋白酶激活为纤溶酶：组织型纤溶酶原激活物（tPA）和尿激酶型纤溶酶原激活物（uPA），该过程受纤溶酶原激活物抑制剂 1（PAI-1）调节，PAI-1 是一种丝氨酸蛋白酶抑制剂，特异性抑制 tPA 和 uPA。疟原虫配子和孢子利用 tPA 和 uPA 激活纤溶酶原，寄生虫结合的纤溶酶降解细胞外基质，促进寄生虫在蚊子和哺乳动物宿主中的运动。此外，PAI-1 强烈抑制纤溶酶原激活可强烈阻止两种宿主的感染。为了阻断寄生虫对纤溶酶的利用，我们构建了表达人 PAI-1（huPAI-1）的转基因按蚊，该蛋白在中肠腔、唾液或两者中持续分泌。表达 huPAI-1 的蚊子强烈降低了啮齿动物和人类疟原虫寄生虫向蚊子的传播，表明利用纤溶酶进行蚊子感染是疟原虫属之间的一种保守机制。唾液中的 huPAI-1 表达诱导唾液腺变形，影响孢子入侵和 P. berghei 向小鼠的传播，从而显著保护免受疟疾侵害。使用基因工程蚊子靶向疟疾寄生虫与纤维蛋白溶解系统的相互作用，可以开发出一种干预措施来控制疟疾传播。
