ROLE OF CYCLIC AMP IN CYST CELL PROLIFERATION

产品描述：常染色体显性遗传性多囊肾病（ADPKD）是一种慢性进行性肾脏疾病，其特征是由肾小管衍生的无数上皮囊肿的发展和稳定扩大。肾小管上皮细胞的增殖是囊肿产生和扩大的重要过程。新的证据表明，ADPKD囊肿上皮细胞可能是异常敏感的有丝分裂作用的环状ANT。该项目基于我们的新发现，即cAMP刺激ADPKD囊肿上皮细胞的体外增殖，PD 98059是一种高度选择性的丝裂原激活ERK通路抑制剂，可阻断核苷酸的这些作用。相比之下，正常人肾皮质（HKC）细胞在体外不增殖cAMP的反应。本项目的中心目的是检验以下假设：在ADPKD中，细胞内MAP水平升高加速肾囊肿扩大。这种核苷酸通过激活蛋白激酶A，刺激MAP激酶途径，导致持续的上皮细胞有丝分裂和细胞增殖。1）来自人ADPKD囊肿和正常人肾皮质（HKC）的上皮细胞，以及cAMP敏感和不敏感的NOCK细胞株将用于确定增殖对细胞内cAMP浓度的依赖性和细胞凋亡在总体增殖反应中的作用; 2）确定ERK 1、2、MEK和Raf-I在cAMP介导的反应性肾上皮细胞增殖增加中的参与水平; 3）确定Rap-I和B-Raf在cAMP介导的反应性肾上皮细胞增殖增加中的参与水平; 4）确定细胞内cAMP水平的原位变化是否改变具有遗传形式的PKD的Han：SPRD大鼠和CD 1 pCY小鼠中疾病进展的速率。实现这些目标需要应用分子生物学、细胞生物学、生物化学、药理学和细胞生理学以及综合生理学等技术。这些研究将产生新的见解的分子机制，管理肾囊肿的扩大，并提供了一个框架的设计治疗措施，以打击进行性破坏肾实质囊肿。

Description: (Taken directly from the application) Autosomal dominant polycystic kidney disease (ADPKD) is a slowly progressive renal disorder characterized by the development and steady enlargement of innumerable epithelial cysts that are derived from renal tubules. Proliferation of tubule epithelial cells is an important process in the generation and enlargement of cysts. New evidence indicates that ADPKD cyst epithelial cells may be unusually sensitive to a mitogenic action of cyclic ANT. This project is based on our new findings that cAMP stimulates the in vitro proliferation of ADPKD cyst epithelial cells and that PD98059, a highly selective inhibitor of the mitogen-activated-ERK-pathway, blocks these effects of the nucleotide. By contrast, cells of normal human kidney cortex (HKC) do not proliferate in response to cAMP in vitro. The central thrust of this project is to test the hypothesis that: In ADPKD, renal cyst enlargement is accelerated by elevated levels of intracellular MAP. This nucleotide, through the activation of protein kinase A, stimulates the MAP kinase pathway leading to sustained epithelial mitogenesis and cellular proliferation. The following Specific Aims will test this hypothesis: 1) Epithelial cells from human ADPKD cysts and normal human kidney cortex (HKC), and cAMP sensitive and insensitive strains of NOCK cells will be used to determine the dependence of proliferation on intracellular concentrations of cAMP and the role of apoptosis in the overall proliferative response; 2) Determine the level of involvement of ERK 1,2, MEK and Raf-I in the cAMP-mediated increase in proliferation of responsive renal epithelial cells; 3) Determine the involvement of Rap-I and B-Raf in cAMP-mediated increase in proliferation of responsive renal epithelial cells; 4) Determine if changes in intracellular cAMP levels in situ alter the rate of disease progression in Han: SPRD rats and CD1 pCY mice with inherited forms of PKD. Achievement of these aims requires application of the techniques of molecular biology, cell biology, biochemistry, pharmacology and cellular and integrative physiology. These studies will yield new insights into the molecular mechanisms governing the enlargement of renal cysts and provide a framework for the design of therapeutic measures to combat the progressive destruction of renal parenchyma by cysts.