Novel Short ACE2 variant for Delayed Graft Function

项目总结 移植肾功能延迟(Dgf)是急性肾损伤的一种形式，临床上定义为需要在一个月内进行透析。 肾移植周。它影响高达50%的已故捐赠者肾移植接受者。因为. 器官短缺危机、边缘或扩大的标准捐赠者肾脏越来越多地被考虑，尽管 这些肾脏发生DGF的风险更高。患有DGF的患者发生同种异体排斥反应的风险更高 死亡。DGF主要由缺血所致的急性近端肾小管损伤引起。 到目前为止，还没有FDA批准的治疗方法。移植肾功能延迟的治疗或预防， 因此，DGF的临床需求尚未得到满足，迫切需要新的方法来预防和减轻DGF。 在这项建议中，我们想要检查给予较短的血管紧张素转换的预防价值。 酶2(ACE2)变种。我们有初步数据表明，一种矮小的小鼠血管紧张素转换酶2变体可以预防急性胰腺炎 缺血再灌注损伤(IRI)所致的肾脏损伤(AKI)。因为缺血再灌注损伤是驱动力 对于DGF，我们提出了一种新的人类ACE2短变异体可以预防和减弱DGF。ACE2是一种 肾脏中丰富的组织酶，能分解氨基酸苯丙氨酸形成血管紧张素(Ang)(1- 7)来自Ang II(Ang(1-8))。在ACE2缺乏的遗传模型中，缺血再灌注诱导的AKI 据报道，AKI患者肾脏ACE2活性下降，导致 血管紧张素转换酶1-7由血管紧张素转换酶II形成。因此，用血管紧张素转换酶抑制剂对肾脏给予血管紧张素转换酶2是有道理的。 并延伸到预防/减弱DGF。 我们建议研究一种新的人类ACE2变异体的潜在预防/治疗效果 比天然的可溶性血管紧张素转换酶2短，因此可通过肾小球滤过屏障过滤，从而使其 可被肾脏近端小管摄取，在那里它促进Ang II的降解和形成 Ang 1-7.通过这种方法，血管紧张素II的形成继续进行，这样体循环和肾脏循环就可以 在不引起低血压或损害肾小球血流动力学的情况下，由这种关键多肽维持。 我们已经将我们较短的人类ACE2变异体与白蛋白结合结构域(ABD)融合在一起，作为扩展的策略 行动的持续时间从几小时到几天不等。我们计划在同基因肾移植的小鼠身上检测IF 将这种新的ACE2变体应用于接受了4小时冷处理的移植物的受者 缺血可改善移植肾延迟功能，提高肾脏ACE2活性。此外，还将对其进行检查 如果肾移植前体外灌流这种ACE2变异体的移植肾可以预防 移植物功能延迟。

Project summary Delayed graft function (DGF) is a form of acute kidney injury clinically defined as the need for dialysis within one week of kidney transplantation. It affects up to 50% of deceased-donor kidney transplant recipients. Because of the organ shortage crisis, marginal or expanded criteria donor kidneys are increasingly considered even though these kidneys are at higher risk to develop DGF. Patients with DGF have a higher risk of allograft rejection and death. DGF is largely caused by acute proximal tubular injury induced by ischemia. There are no FDA-approved treatments available to date. Treatment or prevention of delayed graft function, therefore, poses an unmet clinical need and new approaches to prevent and attenuate DGF are urgently needed. In this proposal, we want to examine the preventative value of administering a shorter angiotensin converting enzyme 2 (ACE2) variant . We have preliminary data that a short mouse ACE2 variant protects against acute kidney injury (AKI) caused by ischemia reperfusion injury (IRI). As ischemia reperfusion injury is the driving force of DGF, we propose that a novel short human ACE2 variant can prevent and attenuate DGF. ACE2 is a tissue enzyme abundant in the kidneys that cleaves the amino acid phenylalanine to form Angiotensin (Ang) (1- 7) from Ang II (Ang (1-8)). In a genetic model of ACE2 deficiency, AKI induced by ischemia-reperfusion is aggravated and moreover a decrease in kidney ACE2 activity has been reported in AKI which leads to less formation of Ang 1-7 from Ang II. Therefore, there is a rationale for administering ACE2 to the kidney with AKI and by extension to prevent / attenuate DGF. We propose to examine the potential preventative / therapeutic effect of a novel human ACE2 variant which is shorter than the native soluble ACE2 and therefore filterable across the glomerular filtration barrier such that it can be taken up by the kidney proximal tubule where it fosters the degradation of Ang II and the formation of Ang 1-7. With this approach, the formation of Ang II continues, such that the systemic and renal circulation can be sustained by this critical peptide without causing hypotension or compromising glomerular hemodynamics. We have fused our shorter human ACE2 variant with an Albumin binding domain (ABD), as a strategy to extend the duration of action from hours to days. We plan to examine if in mice with syngeneic kidney transplantation administration of this novel ACE2 variant to the recipient that has received a graft subjected to 4 hours of cold ischemia will improve delayed graft function and increase kidney ACE2 activity. Additionally, it will be examined if perfusion of the kidney graft ex vivo with this ACE2 variant prior to kidney transplantation protects against delayed graft function.