Role of PI3 Kinase p110alpha in Osteoclasts

描述（由申请人提供）：破骨细胞功能障碍导致与疾病相关的病理性骨丢失，包括类风湿性关节炎、牙周病、骨质疏松症和转移性骨肿瘤。磷脂酰肌醇3-激酶（PI 3-kinases）的信号转导是调节骨细胞骨吸收的关键。三种不同类型的PI 3-激酶的成员在破骨细胞中表达。这些类别在结构、底物特异性和靶向元件方面不同。它们被认为发挥不同的生理作用，尽管这些分工尚不清楚。到目前为止，很少有数据是关于每种类型的PI 3-激酶在破骨细胞中的确切作用。本研究的中心假设是PI 3-激酶在破骨细胞中具有不同的调节作用。通过腺相关病毒（AAV）为基础的基因转移技术，已经在成熟破骨细胞中表达了I类PI 3-激酶（p110 α）亚型的有效反义物。目前的建议有三个具体目标。首先，将确认p110 α敲低的程度和特异性。如有必要，将采用额外的击倒方法。第二，将检查敲低p110 α表达对细胞骨架组织、细胞极性、破骨细胞数量和骨吸收的影响。最后，将确定敲低p110 α表达对破骨细胞存活和凋亡的影响。总之，通过敲低p110 α的表达，并使用破骨细胞的发育、活性和存活测定来表征其作用，我们应该能够为这种酶分配特定的作用。这些研究可能导致开发新的，特定的，具有改善牙齿健康潜力的骨活性药物。

DESCRIPTION (provided by applicant): Dysfunction of osteoclasts leads to pathological bone loss associated with diseases including rheumatoid arthritis, periodontal disease, osteoporosis and metastatic bone tumors. Signal transduction by a group of enzymes called phosphatidylinositol 3-kinases (PI 3-kinases) is known to be crucial for regulating osteoclastic bone resorption. Members of three distinct classes of PI 3-kinase are expressed in osteoclasts. The classes differ in structure, substrate specificity and targeting elements. They are thought to play distinct physiologic roles, although these divisions are not yet clear. To date, few data are available about the precise role of each type of PI 3-kinase in osteoclasts. The central hypothesis of this study is that the PI 3-kinases have non-identical regulatory roles in osteoclasts. An effective antisense to an isoform of a subclass of the class I PI 3-kinase (p110alpha) has been expressed in mature osteoclasts by adeno-associated virus (AAV) based gene transfer techniques. The current proposal has three specific Aims. First, the extent and specificity of the p110alpha knock down will be confirmed. If necessary, additional knockdown approaches will be utilized. Second, the effects of knocking down expression of p110alpha on cytoskeletal organization, cell polarity, osteoclast number and bone resorption will be examined. Finally, the effects of knocking down expression of p110alpha on osteoclast survival and apoptosis will be determined. In summary, by knocking down expression of p110alpha and characterizing the effects using assays for the development, activity and survival of osteoclasts, we should be able to assign specific roles for this enzyme. These studies could lead to the development of new, specific, bone active pharmaceuticals with the potential to improve dental health.