Protein Kinase A (PKA) Signaling in the Cystogenesis and Dedifferentiation of Proximal Tubules

近端小管囊肿发生和去分化中的蛋白激酶 A (PKA) 信号转导

• 批准号: 10000947
• 负责人: Pawan Puri
• 金额: $ 14.7万
• 依托单位: TUSKEGEE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-12 至 2023-07-16
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10000947
• 关键词: Affect; Automobile Driving; Autosomal Dominant Polycystic Kidney; Biological Assay; Cells; Childhood; Clinical Trials; Complement; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Cyst; Cystic Kidney Diseases; Data; Development; Differentiation Antigens; Disease model; Duct (organ) structure; Early Intervention; Ectopic Expression; Embryo; End stage renal failure; Epithelial Cells; Event; Failure; Fibrosis; Foundations; Future; Genetic Diseases; Goals; Growth; Histologic; Hormones; In Vitro; Inflammation; Injury; Kidney; Lead; Mediating; Molecular Analysis; Mutation; Outcome; PKD1 gene; Pathology; Pathway interactions; Patients; Pattern; Phosphorylation; Phosphotransferases; Play; Polycystic Kidney Diseases; Process; Protein Inhibition; Proximal Kidney Tubules; Publishing; Regulation; Renal function; Role; Second Messenger Systems; Signal Pathway; Signal Transduction; Tamoxifen; Testing; Transgenic Mice; Treatment Efficacy; Tubular formation; Vasopressin Antagonist; Vasopressin Receptor; Vasopressins; Water; Wild Type Mouse; absorption; analog; in vivo; mouse model; mutant; new therapeutic target; novel; preservation; progenitor; protein activation; receptor; response; therapeutic target; transcription factor

Project Summary Autosomal dominant polycystic kidney disease (ADPKD) affects more than 600,000 people in the USA and is caused by mutations primarily in genes PKD1 and PKD2. In ADPKD, cysts and fibrosis replace the renal parenchyma leading to renal pathology and failure. Currently, in the USA there are no approved therapies to stop or slow cyst growth. Increased levels of second messenger cAMP is one of the key initial events associated with PKD mutations. cAMP activates multiple signaling pathways including the Protein Kinase A (PKA) pathway that results in phosphorylation of transcription factor Creb and other substrates. Cysts may arise from different tubular segments in PKD such as proximal tubules (PTs) and collecting ducts (CDs). Potential therapies to modulate cAMP/PKA signaling in CD-derived cysts are under clinical trials however, strategies to control cAMP/PKA signaling in PT-derived cysts remain largely undefined. Furthermore, early interventions during childhood to reduce cystic burden have been recommended to preserve maximum renal function. Available data suggest that PT-derived cysts predominate in the developing kidney. Our recently published studies suggest that cAMP-mediated PKA activation plays a key role in the cystogenesis of PTs of the developing kidneys. Our studies also suggest that PKA contributes to the dedifferentiation of PT cystic segments of the developing and developed kidney, a process known to contribute to cystogenesis. Proximity of PKA to cAMP makes it a suitable therapeutic target however, the direct role of PKA in PT cystogenesis has not been investigated. The objective of this proposal is to test the overarching hypothesis that aberrant cAMP/PKA signaling is a key factor driving PT de-differentiation that promotes cyst formation in the kidney. This hypothesis will be tested in the following two aims. Aim 1: Examine the direct effect of PKA in the dedifferentiation of PTs in culture. We will determine whether modulation of PKA activity in in vitro cultures is sufficient and/or necessary for PT dedifferentiation as an early step to cystogenesis. Aim 2: Determine the effects of constitutive PKA activation on the cystogenesis and dedifferentiation of PTs in vivo. We will determine whether constitutive activation of PKA in differentiated PTs is sufficient to induce their de-differentiation, leading to cystogenesis as well as initiate multi-faceted cellular responses such as fibrosis and inflammation-associated changes from the surrounding renal parenchyma. These studies will define a direct novel role of PKA in the dedifferentiation and cystogenesis of PT and establish PKA as a potential therapeutic target. These studies will lay the foundation for the future studies that will determine whether modulation of PKA activity in PTs exacerbates or ameliorates cystogenesis and dedifferentiation in a PKD mouse model. Future studies will also focus to identify novel substrates of PKA implicated in the dedifferentiation and cystogenesis of PTs.

项目摘要 常染色体显性遗传性多囊肾病(ADPKD)在美国影响着60多万人，目前 主要由PKD1和PKD2基因突变引起。在ADPKD中，囊性病变和纤维化取代了肾脏 导致肾脏病理和衰竭的实质。目前，在美国还没有批准的治疗方法来治疗 阻止或减缓囊泡的生长。第二信使阵营水平的增加是相关的关键初始事件之一 有PKD突变。CAMP激活包括蛋白激酶A(PKA)通路在内的多条信号通路 这会导致转录因子Creb和其他底物的磷酸化。囊肿可能由不同的原因引起 PKD中的管段，如近端小管(PTS)和集合管(CDS)。潜在的治疗方法 然而，调控cAMP/PKA信号在CD来源的囊肿中的临床试验中，控制策略 甲状旁腺囊肿中的cAMP/PKA信号在很大程度上仍不明确。此外，期间的早期干预措施 儿童时期应尽量减少囊性负担，以最大限度地保护肾功能。可用数据 提示在发育中的肾脏中，甲状旁腺样囊性病变占主导地位。我们最近发表的研究表明 CAMP介导的PKA活化在发育中肾脏PTS的囊变过程中起关键作用。我们的 研究还表明，PKA在发育中和发育中的甲状腺乳头状瘤囊性节段的去分化中起作用。 肾脏发育，这是一个已知有助于囊变的过程。PKA距离营地很近，因此它是一个合适的 然而，PKA在甲状旁腺囊变发生中的直接作用尚未被研究。目标是 这一提议的目的是检验cAMP/PKA信号异常是推动 PT去分化，促进肾脏内的囊变形成。这一假设将在以下方面得到检验 两个目标。目的1：探讨PKA在PTS细胞脱分化过程中的直接作用。我们将决定 体外培养中PKA活性的调节是否足以和/或必要地促进PT的脱分化 囊性发育的早期步骤。目的2：确定组成性蛋白激酶A激活在囊变发生中的作用 体内PTS的去分化作用。我们将确定在分化中是否存在PKA的结构性激活 PTS足以诱导其去分化，导致囊变，并启动多方面的细胞 周围肾实质的纤维化和炎症相关改变等反应。 这些研究将明确PKA在甲状旁腺脱分化和囊变中的直接新作用，并建立 PKA作为一种潜在的治疗靶点。这些研究将为今后的研究奠定基础， 确定PTS中PKA活性的调节是否加剧或改善了膀胱发生和 PKD小鼠模型中的去分化。未来的研究还将集中于寻找新的PKA底物 与PTS的去分化和囊变有关。