Guanylyl cyclase receptors: Targets for medical intervention

我们将定义GCB（NPR-B）的功能，GCB是一种膜鸟苷酸环化酶受体，由局部细胞激活。 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激活通常导致细胞增殖和肥大的抑制。 我们最近发现鞘氨醇-1-磷酸（S1 P）是一种强效、有效和高度特异性的GCB 减敏因子第一个具体目标集中在S1 P通过其表达的分子途径上。 特异性诱导GCB脱敏。这些研究是重要的，因为CNP，它作为一个 S1 P拮抗剂，强烈暗示在组织重塑中具有重要作用，包括 动脉粥样硬化、血管成形术后再狭窄，甚至肝脏疾病。小鼠遗传模型，siRNA和 相互作用捕获筛选（免疫沉淀，酵母双杂交，Sos-Ras）将确定介导 S1 P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。这些蛋白质本身将用于相互作用陷阱筛选， 定义S1 P-GCB脱敏途径中的其他分子。GCB的脱敏最终是 通过受体的去磷酸化调节，因此蛋白激酶/蛋白磷酸酶 负责GCB调节的基因将被纯化、鉴定并确定调节机制。我们也 已经破坏了GCB基因，然后通过GCB特异性表达来纠正严重的侏儒症。 软骨细胞在空背景中。与野生型相比，这些GCB动物几乎不含脂肪 同窝出生的因此，第二个具体目标集中于GCB在成纤维细胞中的功能作用， 脂肪细胞我们将比较各种治疗（体外和体内）对成纤维细胞和成纤维细胞的影响。 脂肪细胞功能，特别强调GCB在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而实质性的影响。 疾病，因为在美国最大的健康问题之一是肥胖，往往是由过量的 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与肥胖相关的许多疾病。

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.