Endothelial Cell in Progressive Renal Disease

描述（由申请人提供）：肾衰竭正以6%的速度增长，每年耗资160亿美元；因此，开发新的肾脏疾病治疗方法是至关重要的。在之前的更新中，我们证明了血管内皮生长因子（VEGF）的组成表达缺失发生在几种肾脏疾病模型中，并且VEGF的替代可以通过其刺激肾毛细血管修复的能力来减缓进展。在这个建议中，我们继续我们的肾脏疾病的生理和病理生理VEGF的研究。在Aim 1中，我们将验证特定小管细胞（收集管和髓质厚升肢细胞）中VEGF的组成性表达在发育和成年动物的肾（小管周围）毛细血管中起关键的营养作用的假设。这将通过使用Cre-loxP方法选择性地敲除这些小管细胞中的VEGF来进行测试。在Aim 2中，我们将验证当内皮NO水平低时，VEGF给药可能没有好处的假设，事实上，VEGF可能通过对单核细胞和血管平滑肌细胞的影响加速血管疾病。这将通过检查长期VEGF表达（通过使用AAV载体系统进行基因转移）在内源性NO水平降低或维持的肾脏疾病中的影响来验证。在Aim 3中，我们将检验特异性VEGF受体可能决定VEGF刺激是好是坏的假设，因为VEGFR-1的刺激预计会加剧肾血管损伤，而VEGFR-2的刺激应该加速毛细血管修复和肾脏恢复，而不依赖于NO系统的状态。这将通过在存在或不存在NO阻断的情况下，肾脏疾病中每种受体特异性VEGF突变体的过表达来测试。关于VEGF在正常肾脏中的作用、NO系统介导VEGF反应的重要性以及每种受体在这一过程中的具体作用的文献，将为指导未来使用VEGF作为一种新的肾脏疾病治疗方法的研究提供关键信息。

DESCRIPTION (provided by applicant): Renal failure is increasing at the rate of 6% with a cost of 16 billion dollars per year; thus developing new therapies for kidney disease is of paramount importance. In the previous renewal, we demonstrated that a loss of constitutive expression of vascular endothelial growth factor (VEGF) occurs in several models of renal disease, and that replacement with VEGF could slow progression via its ability to stimulate renal capillary repair. In this proposal we continue our studies of the physiology and pathophysiology of VEGF in renal disease. In Aim 1 we will test the hypothesis that the constitutive expression of VEGF in specific tubular cells (collecting ducts and medullary thick ascending limb cells) plays a critical trophic role for the renal (peritubular) capillaries in development and in the adult animal. This will be tested by selectively knocking out VEGF in these tubular cells using the Cre-loxP approach. In Aim 2 we will test the hypothesis that VEGF administration may not be beneficial when endothelial NO levels are low, and in fact may accelerate vascular disease via its effects on monocytes and vascular smooth muscle cells. This will be tested by examining the effect of long-term VEGF expression (by gene transfer using the AAV vector system) in renal diseases in which endogenous NO levels are reduced or maintained. In Aim 3 we will test the hypothesis that the specific VEGF receptors may govern whether VEGF stimulation is good or bad, in that stimulation of VEGFR-1 is expected to exacerbate renal vascular injury whereas stimulation of VEGFR-2 should accelerate capillary repair and renal recovery, independent of the status of the NO system. This will be tested by the overexpression of VEGF mutants specific for each receptor in renal diseases in the presence or absence of NO blockade. Documentation of the role of VEGF in the normal kidney, the importance of the NO system in mediating the responses to VEGF, and the specific role of each receptor in this process should provide the key information to help guide future studies for the use of VEGF as a novel treatment of kidney disease.