Causal connections between axon guidance proteins and early progressive kidney function decline in diabetes

项目总结/摘要 尽管血糖控制有所改善，但糖尿病导致的终末期肾病（ESKD）继续上升 以及广泛使用保护肾脏的药物。更全面地了解这些机制 因此，迫切需要寻找新的，更有效的， 治疗和预防糖尿病ESKD的方法。通过研究糖尿病晚期肾病患者， 在患有蛋白尿和CKD≥3的疾病中，我们获得了两个与T1 D和T1 D患者进展为ESKD相关的新发现。 和T2 D。使用来自两个独立队列和全球miRNAs平台的随访数据，我们发现了一个特异性的 血浆miRNA谱与ESKD进展密切相关。这些miRNAs特异性靶向 轴突导向通路（AGP）蛋白。引人注目的是，6种AGP蛋白（两种配体EFNA 4， EFN 5和4种受体EPHA 2、EPHB 2、EPHB 6、UNC 5C）与肾损害程度密切相关， T2 D皮马印第安队列中的结构性病变和四个独立队列中进展为ESKD。我们 这一发现首次提示循环中的AGP蛋白参与糖尿病ESKD的进展。 为了跟进这些发现，我们提出了一个多学科的研究，以评估AGP蛋白在肿瘤中的作用。 早期进行性肾功能下降（PKFD）的发展，并了解其机制， 循环中的AGP可能损害肾脏。提出了三项补充研究。克罗莱夫斯基博士的实验室 检查AGP蛋白EFNA 4和EPHA 2的两个示例的水平升高是否与 与早期PKFD的发生有关。Kretzler博士的实验室将检测循环中的AGP水平 蛋白质可能影响肾细胞中的候选病因学途径。Korstanje博士的实验室将检查 糖尿病小鼠模型中EFNA 4和EPHA 2循环水平的遗传操作导致糖尿病的发作。 糖尿病肾病拟议的研究有以下具体目标： 目的#1：我们将检查候选miRNAs和AGP蛋白循环水平变化的影响 在两项针对正常白蛋白（n=390）和微量白蛋白（n=390）的T1 D患者的巢式病例对照研究中， Alb（n=430）对7-15年随访期间早期PKFD风险的影响。目标#2：我们将研究 候选AGP蛋白的循环水平和候选病因学途径的失调，使用单 细胞RNA测序结果来自患有T2 D的皮马印第安人的研究肾活检。目标3：我们 将测试EPHA 2和EFNA 4在糖尿病小鼠模型中修饰肾表型的能力，并测试 miR-328- 5 p和miR-339- 5 p在ESKD进展过程中均下调， 小鼠中的直向同源物，可以影响这些AGP蛋白对糖尿病肾病的影响。 拟议的研究有很高的可能性产生新的发现。它的成功是由 事实上，共同研究者有合作的跟踪记录，研究队列和标本生物库 来自乔斯林肾脏研究和皮马印度肾脏研究的所有成员。

PROJECT SUMMARY/ABSTRACT End stage kidney disease (ESKD) due to diabetes continues to rise despite improvements in glycemic control and widespread treatment with reno-protective drugs. A more complete understanding of the mechanisms responsible for the progressive decline in kidney function is urgently needed to identify new, more efficacious methods of treatment and prevention of ESKD in diabetes. By studying diabetic patients with advanced kidney disease with proteinuria and CKD≥3, we obtained two novel findings related to progression to ESKD in both T1D and T2D. Using follow-up data from two independent cohorts and global miRNAs platform, we found a specific profile of plasma miRNAs strongly associated with progression to ESKD. These miRNAs specifically targeted axon guidance pathway (AGP) proteins. Strikingly, circulating levels of 6 AGP proteins (two ligands EFNA4, EFN5 and 4 receptors EPHA2, EPHB2, EPHB6, UNC5C) were very strongly associated with the extent of kidney structural lesions in the T2D Pima Indian cohort and progression to ESKD in four independent cohorts. Our findings are the first to implicate circulating AGP proteins in the progression to ESKD in diabetes. To follow-up these findings, we propose a multi-disciplinary study to assess the role of the AGP proteins in the development of early progressive kidney functional decline (PKFD) and learn about mechanisms through which circulating AGP may damage the kidney. Three complementary studies are proposed. Dr. Krolewski’s lab will examine whether elevated levels of two exemplars of AGP proteins EFNA4 and EPHA2 are associated/causally related to the development of early PKFD. Dr. Kretzler’s lab will examine how circulating levels of the AGP proteins may impact candidate etiological pathways in kidney cells. Dr. Korstanje’s lab will examine whether genetic manipulation of circulating levels of EFNA4 and EPHA2 in mice models of diabetes lead to onset of diabetic kidney disease. The proposed research has the following specific aims: Aim #1: We will examine the effect of variation of circulating levels of the candidate miRNAs and AGP proteins examined at baseline in the two nested cases-control studies of T1D patients with Normo-Alb (n=390) and Micro- Alb (n=430) on risk of early PKFD during 7-15 years of follow-up. Aim #2: We will examine the link between circulating levels of the candidate AGP proteins and dysregulation of candidate etiological pathways using single cell RNA sequencing results obtained from research kidney biopsies from Pima Indians with T2D. Aim #3: We will test EPHA2 and EFNA4 for their ability to modify renal phenotypes in a diabetic mouse model and test whether miR-328-5p and miR-339-5p, which are both downregulated during progression to ESKD and have orthologs in the mouse, can affect the impact of these AGP proteins on diabetic kidney disease. The proposed research has a very high probability of generating novel findings. Its success is assured by the fact that the co-investigators have a track record of collaboration, and study cohorts and biobanks of specimens from all members of the Joslin Kidney Study and Pima Indian Kidney Study are available.