Estrogen Negatively Modulates Proteoglycan-4 Expression in TMJ

 描述（由申请人提供）：颞下颌关节紊乱病（TMD）影响了美国很大一部分人口，大多数寻求治疗的人是育龄妇女。由于这种显著的两性异形，人们推测性激素在维持正常的颞下颌关节（TMJ）功能中起作用。蛋白聚糖4（Proteoglycan 4，PRG4）是一种分泌型润滑分子，对维持关节内低摩擦水平至关重要，但其在TMJ中的作用尚不清楚 表征了我们在人和狒狒PRG4基因的5'侧翼区域内鉴定了保守的雌激素反应元件，并发现用雌激素处理狒狒TMJ盘细胞在体外减弱PRG4启动子活性和PRG4 mRNA的表达。雌激素对PRG4负调节的发现是TMD发展中的致病事件是雌激素介导的PRG4转录下调的假设的基础。预计TMJ中PRG4的量不足会导致摩擦增加，并且随着时间的推移，TMJ组件的降解会影响下颌髁突与颞骨的关节窝的关节连接和椎间盘放置，这在很大程度上描述了人类TMD表型。在这项研究中，我们提出了三个具体的目标：1）确定雌激素降低PRG4在雌性和雄性狒狒TMJ细胞和TMJ器官型培养物中表达的程度。免疫印迹和qPCR将用于定量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椎间盘细胞和组织中的PRG4表达进行比较。2)通过ChIP分析雌性和狒狒TMJ细胞中PRG4基因调控中的雌激素α和β受体以及雌激素反应元件结合。3)为生命科学领域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.