Role of NOX4 and redox environment in Autosomal Dominant Polycystic Kidney Disease

常染色体显性遗传性多囊肾病(ADPKD)是一种破坏性的系统性疾病，导致 美国医疗保健系统每年的成本约为33亿美元。它的特点是进步性 双侧肾囊肿的发展和增大导致肾功能衰竭。早期肾单位保护 策略可能会改变疾病的进程，但导致疾病严重性和 进展仍未完全阐明，限制了新疗法的发展。此外，以下是 由于大的表型，对患者的治疗反应的UP和评估是一个主要的挑战 变异性、疾病的自然病程以及目前可用的生物标志物的局限性。一直以来 提出功能性多囊蛋白-1和多囊蛋白-2(主要的ADPKD蛋白产物)的缺失导致减少 细胞内Ca+2、cAMP积聚和蛋白激酶A(PKA)信号的激活。此外，ADPKD 与肾脏活性氧簇(ROS)升高、线粒体异常和 疾病早期的代谢失调，可能影响疾病的进展。两者之间的联系 这些进程仍未得到解决。细胞内信号、细胞器和代谢途径是 受氧化还原环境的影响，氧化还原环境是由ROS的产生和去除决定的，这是由于 ROS激活或停用各种酶和信号分子的能力。我们的初步数据在 Pkd1RC/RC小鼠表现出肾脏ROS产生NADPH氧化酶4(NOX4)的早期上调，与 线粒体异常和代谢紊乱与疾病严重程度和 进步。在Pkd1RC/RC模型中，NOX4上调和代谢异常更加明显 随着PKA的结构性上调，与先前在内皮细胞中显示上调的研究一致 通过cAMP/PKA/CREB依赖的途径表达NOX4。NOX4对细胞氧化还原环境的影响及其机制 对线粒体功能和代谢途径的影响，以及PKA信号的激活是否导致 NOX4的上调尚不清楚。我们的中心假设是PKA介导的NOX4上调， 动态调节细胞氧化还原环境导致线粒体异常和 代谢紊乱，并导致疾病的严重程度和进展。三个具体目标将 追求：目标1：将确定NOX4对细胞氧化还原环境、线粒体结构的影响 ADPKD的功能和代谢途径，以及对疾病严重程度和进展的贡献。目标 2：将检测PKA信号的激活是否诱导ADPKD早期NOX4的上调。目标3：意志 确定尿NOX4，线粒体损伤和氧化应激的替代标记物是否有用 实时生物标记物评估早期ADPKD患者的疾病严重程度和进展。成功 这些研究将对促进对ROS在ADPKD中的作用的理解具有重要的临床意义。 在ADPKD中提供潜在的可修改的治疗靶点和识别新的早期生物标志物。

Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a devastating systemic disorder, resulting in approximately $3.3 billion cost per year to the US health care system. It is characterized by progressive development and enlargement of bilateral renal cysts leading to renal failure. Early nephron-protective strategies may alter the course of the disease, but the mechanisms contributing to disease severity and progression remain to be fully elucidated, limiting the development of new therapies. Furthermore, the follow up and evaluation of a treatment response in patients represents a major challenge due to the large phenotypic variability, the natural course of the disease and limitations in currently available biomarkers. It has been proposed that loss of functional polycystin-1 and polycystin-2 (main ADPKD protein products) result in reduced intracellular Ca+2, cAMP accumulation and activation of protein kinase A (PKA) signaling. In addition, ADPKD has been associated with increased renal reactive oxygen species (ROS), mitochondrial abnormalities and metabolic dysregulations early on the disease, likely influencing disease progression. The connection between these processes remains unresolved. Intracellular signaling, organelles, and metabolic pathways are influenced by the redox environment, which is determined by the production and removal of ROS, due to ROS's ability to activate or deactivate a variety of enzymes and signaling molecules. Our preliminary data in Pkd1RC/RC mice shows an early upregulation in renal ROS producer NADPH oxidase 4 (NOX4), associated with mitochondrial abnormalities and metabolic dysregulations that correlates with disease severity and progression. NOX4 upregulation and metabolic abnormalities were more pronounced in a Pkd1RC/RC model with constitutive upregulation of PKA, consistent with previous studies in endothelial cells showing upregulation of NOX4 via cAMP/PKA/CREB-dependent pathway. How NOX4 affects the cellular redox environment and its influence in mitochondrial function and metabolic pathways, and whether activation of PKA signaling leads to NOX4 upregulation are not known. Our central hypothesis is that PKA-mediated NOX4 upregulation, dynamically regulates the cellular redox environment inducing mitochondrial abnormalities and metabolic dysregulations, and contributes to disease severity and progression. Three specific aims will be pursued: Aim 1: will determine the impact of NOX4 in cellular redox environment, mitochondria structure and function and metabolic pathways in ADPKD and the contribution to disease severity and progression. Aim 2: will test whether activation of PKA signaling induces early NOX4 upregulation in ADPKD. Aim 3: will determine whether urine NOX4, surrogate markers of mitochondria injury and oxidative stress may be useful real-time biomarkers to assess disease severity and progression in patients with early ADPKD. Successful studies will have important clinical implications by advancing the understanding of the role of ROS in ADPKD, providing potentially modifiable therapeutic target and identifying novel early biomarkers in ADPKD.