Estrogen Negatively Modulates Proteoglycan-4 Expression in TMJ

 描述(由申请人提供)：美国有相当一部分人患有颞下颌关节紊乱病(TMD)，寻求治疗的大多数是育龄妇女。由于这种显着的性别二型性，人们推测性激素在维持正常的颞下颌关节(TMJ)功能中起着作用。蛋白多糖4(Proteoglycan 4，PRG4)是一种分泌的润滑分子，对维持关节内的低摩擦水平至关重要；然而，它在TMJ中的作用并不是很好 特色化的。我们在人和狒狒的PRG4基因5‘侧翼区发现了保守的雌激素反应元件，并发现在体外用雌激素处理狒狒TMJ间盘细胞会减弱PRG4启动子的活性和PRG4mRNA的表达。这一发现是雌激素对PRG4负调控的基础，为雌激素介导PRG4转录下调是TMD发生过程中的一个致病事件奠定了基础。TMJ中PRG4的含量不足预计会导致摩擦力增加，随着时间的推移，TMJ组件的降解会影响下颌突与颞骨的关节窝和关节盘的放置，这在很大程度上描述了人类TMD的表型。在这项研究中，我们提出了三个具体的目标：1)确定雌激素在多大程度上降低雌性和雄性狒狒TMJ细胞和TMJ器官培养物中PRG4的表达。免疫印迹和定量聚合酶链式反应将被用来量化雌激素对滑膜和软骨细胞和组织中PRG4表达的影响，并将其与TMJ间盘细胞和组织中PRG4表达进行比较。2)用芯片分析技术研究雌激素α、β受体和雌激素反应元件结合在雌性和狒狒TMJ细胞PRG4基因调控中的作用。3)为生命科学领域中代表性不足的学生提供高度指导的环境和严格的生物医学研究培训机会。

 DESCRIPTION (provided by applicant): Temporomandibular joint disorders (TMDs) affect a significant portion of the population of the USA, with the majority of those seeking treatment being women of childbearing age. Owing to this striking sexual dimorphism it has been postulated that sex hormones play a role in the maintenance of normal temporomandibular joint (TMJ) function. Proteoglycan 4 (PRG4) is a secreted lubricating molecule essential for maintaining low frictional levels within articular joints; however, its role in the TMJ is not well characterized. We identified conserved estrogen response elements within the 5' flanking region of the PRG4 gene of human and baboon, and found that treatment of baboon TMJ disc cells with estrogen attenuated PRG4 promoter activity and expression of PRG4 mRNA in vitro. This discovery of negative regulation of PRG4 by estrogen is the basis for the hypothesis that a causative event in the development of TMD is estrogen-mediated down regulation of PRG4 transcription. Insufficient quantity of PRG4 in the TMJ is expected to lead to increased friction and over time, degradation of TMJ components affecting the articulation of the mandibular condyle with the glenoid fossa of the temporal bone and disc placement, which largely describes the human TMD phenotype. In this study we propose three specific aims; 1) to determine the extent that estrogen decreases PRG4 expression in female and male baboon TMJ cells and TMJ organotypic cultures. Immunoblots and qPCR will be used to quantify estrogen effects on PRG4 expression in synovial and cartilage cells and tissues that will be compared to PRG4 expression in TMJ disc cells and tissue. 2) To characterize by ChIP analysis estrogen alpha and beta receptors and estrogen response element binding in PRG4 gene regulation in femal and baboon TMJ cells. 3) To provide a highly mentored environment and rigorous biomedical research training opportunities for the development of underrepresented students in the life sciences.