Guanylyl cyclase receptors: Targets for medical intervention

我们将定义GCB(NPR-B)的功能，它是一种由局部激活的膜鸟苷酸环化酶受体 旁分泌/自分泌配体，C型利钠肽(CNP)。GCB在软骨细胞中高度表达， 脂肪细胞和成纤维细胞；GCB的激活通常会抑制细胞的增殖和肥大。 我们最近发现鞘氨醇-1-磷酸(S1P)是一种有效的、高度特异的GCB 脱敏因子。第一个具体目标集中在S1P的分子途径上 特异性地诱导GCB脱敏。这些研究在CNP中非常重要，CNP作为一种 S1P的拮抗剂，被认为在组织重塑中具有重要作用，包括 动脉粥样硬化，血管成形术后的再狭窄，甚至肝脏疾病。小鼠遗传模型、siRNA和 相互作用陷阱筛选(免疫沉淀、酵母双杂交、SOS-RAS)将定义介导 S1P诱导的GCB脱敏。在初步研究中，我们已经确定了各种 候选GCB相关蛋白。这些蛋白质本身将被用于相互作用陷阱筛选 定义S1P-GCB脱敏途径中的其他分子。GCB的脱敏最终是 受受体去磷酸化的调节，因此蛋白激酶/蛋白磷酸酶 将对负责GCB监管的人员进行净化、识别并确定监管机制。我们也 已经扰乱了gcb基因，然后通过在 空背景中的软骨细胞。与野生动物相比，这些GCB动物几乎不含脂肪 一窝产仔。因此，第二个特定目标集中在GCB在成纤维细胞和 脂肪细胞。我们将比较不同治疗方法(体外和体内)对成纤维细胞和 脂肪细胞的功能，特别强调GCB在创伤后和创伤后组织重塑中的作用 脂肪细胞分化。拟议的研究将对人类产生重大的影响。 疾病，因为美国最大的健康问题之一是肥胖，肥胖通常是由食物过多引起的 脂肪细胞。肥胖是非胰岛素依赖型糖尿病和高血压的高危因素。因此， 拟议的研究对我们一些最重要的医疗问题产生了影响，包括伤口修复， 动脉粥样硬化，血管成形术后的再狭窄，以及一系列与肥胖相关的疾病。

We will define the functions of GCB (NPR-B), a membrane guanylyl cyclase receptor activated by the local paracrine/autocrine ligand, C-type natriuretic peptide (CNP). GCB is highly expressed in chondrocytes, adipocytes and fibroblasts; GCB activation usually leads to an inhibition of cell proliferation and hypertrophy. We recently identified sphingosine-1 -phosphate (S1P) as a potent, effective and highly specific GCB desensitization factor. The first specific aim concentrates on the molecular pathway by which S1P specifically induces GCB desensitization. These studies are important in that CNP, which acts as an antagonist to S1P, is strongly implicated as having an important role in tissue remodeling, including atherosclerosis, restenosis following angioplasty, and even liver disease. Mouse genetic models, siRNA and interaction trap screens (immunoprecipitation, yeast two hybrid, Sos-Ras) will define proteins that mediate the S1P-induced desensitization of GCB. In preliminary research we have already identified various candidate GCB-associated proteins. These proteins will themselves be used in interaction trap screens to define other molecules within the S1P-GCB desensitization pathway. Desensitization of GCB is ultimately regulated by dephosphorylation of the receptor, and therefore the protein kinase/protein phosphatase responsible for GCB regulation will be purified, identified and mechanisms of regulation determined. We also have disrupted the GCB gene, and then corrected a severe dwarfism by expression of GCB specifically in chondrocytes in the null background. These GCB animals contained almost no fat compared to wild-type littermates. Therefore, the second specific aim concentrates on the functional roles of GCB in fibroblasts and adipocytes. We will compare the effects of various treatments (in vitro and in vivo) on fibroblast and adipocyte function, with particular emphasis on the role of GCB in tissue remodeling after wounding and in adipocyte differentiation. The proposed studies will have significant and substantial implications in human disease, since one of the largest health problems in America is obesity, often caused by an over-abundance of fat cells. Obesity is a high risk factor for non insulin-dependent diabetes and hypertension. Thus, the proposed research impacts on some of our most important medical issues, including wound repair, atherosclerosis, restenosis following angioplasty, and a host of diseases associated with obesity.