Controlling complement to unleash nanomedicine for acute critical illnesses

摘要/总结 急性危重病迅速导致严重的器官损伤和生命损失。这些疾病包括 败血症、中风和急性呼吸窘迫综合征（ARDS）。这里我们关注急性呼吸窘迫综合征， 肺部气囊的炎症，以及COVID-19的死亡原因。对于ARDS和其他疾病， 我们已经开发出了配体靶向纳米载体， 机关当我们走向临床翻译时，我们发现关键的一步是获得对补体的控制， 结合微生物并帮助其清除的血浆蛋白。但我们发现了补体纳米颗粒 相互作用是一把“双刃剑”，既有需要优化的好处，也有需要解决的有害特征。 首先，我们发现补体蛋白C3快速调理特定的纳米颗粒，并且这种C3- 然后调理的纳米颗粒作为“诱饵”来改善ARDS小鼠模型（例如，雾化LPS）约75%。 C3包被的纳米颗粒在边缘白细胞中积累，这是ARDS病理生理学的关键， 并使这些细胞离开肺部然而，C3调理作用诱导过敏样反应，称为 CARPA（补体激活相关假性过敏）。因此，在目标1中，我们将设计纳米颗粒， 可以像C3涂层诱饵一样改善ARDS，但没有CARPA。我们还将调查 纳米颗粒诱饵疗法的潜在机制。然后，我们将测试这些的翻译潜力， 通过在新鲜的、灌注的、离体的人肺中测试它们来优化诱饵纳米颗粒。 其次，我们发现我们一直在开发的用于药物输送的配体靶向纳米颗粒， 年也诱发CARPA。因此，在目标2中，我们将重新设计我们的配体靶向纳米颗粒，以防止 CARPA。我们将测试一种药物载体，我们以前使用它来集中肺泡中的药物。 肺的微血管系统：与结合内皮细胞的抗PECAM抗体缀合的脂质体。我们 将在体外和小鼠体内测试各种工程化版本的抗PECAM脂质体是否可以逃避 C3调理作用和CARPA，从而实现更特异性地递送至肺部。最后，我们将测试这些 CARPA-避免纳米颗粒与来自ARDS患者的血浆，因为这样的患者具有扰动的补体。 在完成这两个目标后，我们将开发出两种技术，可以帮助治疗 ARDS：1）安全地使边缘白细胞离开肺部的诱饵纳米颗粒，从而 改善ARDS样表型; 2）用于预防补体副作用的技术，如CARPA 当递送配体靶向纳米颗粒时。由于边缘白细胞在大多数急性危重病中起关键作用， 疾病，CARPA敏感性也是常见的，这里开发的技术可能不会影响 不仅是急性呼吸窘迫综合征，还有败血症、中风等等。

ABSTRACT / SUMMARY Acute critical illnesses rapidly lead to severe organ damage and loss of life. These illnesses include sepsis, stroke, and acute respiratory distress syndrome (ARDS). Here we focus on ARDS, which is acute inflammation of the lungs’ air sacs, and the cause of death in COVID-19. For ARDS and these other diseases, we have developed ligand-targeted nanocarriers that localize drugs to the inflamed microvasculature of affected organs. As we moved towards clinical translation, we found the key step is gaining control of complement, a set of plasma proteins that bind microbes and aid their clearance. But we found complement-nanoparticle interactions are a “double-edged sword”, with both benefits to optimize, and deleterious features to resolve. First, we found that complement protein C3 rapidly opsonizes particular nanoparticles, and that such C3- opsonized nanoparticles then act as “decoys” to ameliorate ARDS mouse models (e.g., nebulized LPS) by ~75%. The C3-coated nanoparticles accumulate in marginated leukocytes, which are key to ARDS pathophysiology, and cause those cells to leave the lungs. However, C3 opsonization induces an anaphylaxis-like reaction called CARPA (complement-activation-related pseudo-allergy). Therefore, in Aim 1, we will engineer nanoparticles that can function like C3-coated decoys to ameliorate ARDS, but without CARPA. We will also investigate the mechanism underlying nanoparticle decoy therapy. Then we will test the translational potential of these optimized decoy nanoparticles by testing them in fresh, perfused, ex vivo human lungs. Second, we found that the ligand-targeted nanoparticles we have been developing for drug delivery for years also induce CARPA. Therefore, in Aim 2, we will re-engineer our ligand-targeted nanoparticles to prevent CARPA. We will test a drug carrier we have previously used to concentrate drugs in the alveolar microvasculature of the lungs: liposomes conjugated to anti-PECAM antibodies that bind endothelial cells. We will test in vitro and in vivo in mice whether various engineered versions of anti-PECAM liposomes can evade C3 opsonization and CARPA, and thereby achieve more specific delivery to the lungs. Lastly, we will test these CARPA-avoiding nanoparticles with plasma from ARDS patients, as such patients have perturbed complement. Upon completion of these two Aims, we will have developed two technologies that may aid therapy of ARDS: 1) Decoy nanoparticles that safely cause marginated leukocytes to leave the lungs, and thereby ameliorate ARDS-like phenotypes; 2) A technology for preventing complement side effects such as CARPA when delivering ligand-targeted nanoparticles. As marginated leukocytes play pivotal roles in most acute critical illnesses, and CARPA sensitivity is common to those as well, the technologies developed here may impact not only ARDS, but also sepsis, stroke, and more.