Targeting complement inhibitors to the human proximal tubule

描述(申请人提供)：几乎所有的肾小球疾病都伴随着与预后密切相关的肾小管间质(TL)病理。这种TL损伤的发生可能是因为异常的肾小球超滤液含有潜在的损伤蛋白，包括那些自发激活的补体系统的蛋白。虽然大多数宿主细胞具有补体调节蛋白(CRP)，但近端肾小管上皮细胞(PTECs)并不能很好地表达补体调节蛋白。有强有力的数据支持，在蛋白尿条件下，PTEC上会发生有害的C5b-9激活。我们已经使用外源性CRP来限制细胞和组织中补体的激活，包括在肾脏疾病模型中，最近我们使用重组单抗(MAbs)和C3结合补体受体(CR2)来选择性地将CRP靶向补体攻击的相关细胞，包括蛋白尿诱导的TL损伤中的大鼠PTEC。本文提出的研究将应用这一方法将特定的C5b-9抑制剂CD59靶向于人PTEC。第一个目标是研究保留自然特征的人PTEC培养，包括可靶向抗原的表达，CRPS的谱系，以及对C5b-9的功能反应。当接触最近过滤的血浆蛋白时，补体激活可能发生，将在这些细胞上模拟，并确定表型反应，包括与进行性肾脏疾病随着时间的推移发生的平行。然后，我们将评估可用于靶向治疗的PTEC抗原。候选抗原将被研究，包括那些与我们最近在大鼠身上的研究中的人类同源物，以及那些在人类PTEC损伤中上调的抗原。此外，还将评估使用CR2靶向PTEC上补体激活部位的可能性。一旦我们创建了一个模型系统并确定了可行的靶点来传递CRP，我们将创建mAb/CR2-CD59嵌合体来靶向人PTEC。本文提出的工作应用了来自蛋白尿诱导TL损伤的实验模型的基本原理和研究，以开发针对类似人类疾病的治疗方法。肾脏疾病已经达到了流行的程度，给我们造成了生命和金钱上的损失。这里提出的工作使用现代技术来设计这些疾病的治疗方法。尽管这些被认为是试验性和高风险研究，但成功完成可能会为我们提供立即用于临床研究的治疗方法。

DESCRIPTION (provided by applicant): Nearly all glomerular diseases are accompanied by tubulointerstitial (Tl) pathology that is inextricably linked to outcome. Such Tl injury may occur because the abnormal glomerular ultrafiltrate contains potentially injurious proteins, including those of the spontaneously active complement system. Although most host cells bear complement regulatory proteins (CRPs), these are not well expressed by proximal tubular epithelial cells (PTECs). There are strong data supporting that deleterious C5b-9 activation occurs on PTECs in proteinuric conditions. We have used exogenous CRPs to limit complement activation on cells and in tissues, including in renal disease models, and have recently used recombinant monoclonal antibodies (mAbs) and C3-binding complement receptors (CR2) to selectively target CRPs to relevant cells undergoing complement attack, including the rat PTEC in proteinuria-induced Tl injury. The research proposed here will apply this approach to target the specific C5b-9 inhibitor, CD59, to the human PTEC. The first aim will be to study a human PTEC culture that retains native characteristics, including expression of antigens that can be targeted, the repertoire of CRPs, and the functional response to C5b-9. Complement activation as is likely to occur upon exposure to recently filtered plasma proteins will be modeled on these cells, and the phenotypic response determined, including parallels to what occurs over time in progressive renal disease. We will then evaluate PTEC antigens that can be used for targeted therapy. Candidate antigens will be studied, including those with human homologues from our recent studies in the rat, and those upregulated in human PTEC injury. In addition, the potential of using CR2 to target sites of complement activation on the PTEC will be evaluated. Once we have created a model system and identified viable targets to deliver CRPs, we will create mAb/CR2-CD59 chimers to target human PTECs. The work proposed here applies fundamental principles and research derived from experimental models of proteinuria-induced Tl injury to develop therapy for the analogous human diseases. Kidney disease has reached epidemic proportions, costing us in lives and money. The work proposed here uses modern technology to design treatment for these disorders. Although these are considered pilot and high-risk studies, successful completion could give us treatments for immediate use in clinical studies.