Matrix Metallopeptidase 19 (MMP19) and Optic Nerve Disease

描述（申请人提供）：视神经疾病是一个重大的公共卫生问题。几种视神经疾病，包括青光眼和空腔视盘异常（CODA）的定义特征是视神经头部的挖掘或拔罐。然而，在这些疾病中导致视盘突出的生物学途径尚不完全清楚。因此，迫切需要澄清导致视神经组织丢失（挖掘）的生物学机制，以提高我们对疾病过程的理解，并开发包括CODA和青光眼在内的视神经疾病的新治疗方法。我们最近发现基质金属肽酶19 （MMP19）基因突变与CODA有关。具体来说，我们在CODA患者的MMP19基因上游发现了一个6 kb的DNA序列，该序列是三倍的。此外，我们已经证明该序列是一个活跃的增强子，上调MMP19的表达。我们还发现MMP19在视神经头特异性表达，而视神经头是CODA异常发生的地方。此外，基因表达数据显示，MMP19在人类患者和青光眼动物视神经中的表达都大大增加。综上所述，这些发现支持了我们的假设，即MMP19的异常调节促进了CODA视盘的先天性挖掘。我们将通过以下研究目的来验证这一假设：目的1：检测青光眼患者的MMP19突变。我们将对青光眼患者队列进行MMP19拷贝数变异、调控序列突变和编码序列突变的下一代测序测试。目的2：确定调控MMP19表达的特异性增强子元件和转录因子。我们将1)通过诱变研究确定MMP19增强子元件的特定DNA序列，2)使用DNA下拉试验和质谱法分离与MMP19增强子结合的转录因子。本研究将阐明CODA的发病机制，为青光眼视神经拔罐过程提供新的思路。这些研究可能为未来研究开发新的视力保护疗法提供基础。

DESCRIPTION (provided by applicant): Optic nerve diseases are a major public health problem. The defining feature of several optic nerve diseases, including glaucoma and cavitary optic disc anomaly (CODA), is excavation or cupping of the head of the optic nerve. The biological pathways that lead to excavation of the optic disc in these diseases, however, are incompletely understood. Consequently, there is a critical need to clarify the biological mechanisms that lead to loss of tissue (excavation) of the optic nerve to improve our understanding of disease processes and to develop new treatments for optic nerve diseases including CODA and glaucoma. We recently discovered that mutation of the matrix metallopeptidase 19 (MMP19) gene is associated with CODA. Specifically, we discovered a 6 kb DNA sequence upstream of the MMP19 gene that is triplicated in patients with CODA. Moreover, we have proven that this sequence is an active enhancer and upregulates expression of MMP19. We have also shown that MMP19 is specifically expressed in the optic nerve head, where the abnormalities of CODA occur. Moreover, gene expression data shows that MMP19 expression is greatly increased in the optic nerves of both human patients and animals with glaucoma. Together these findings support our hypothesis that abnormal regulation of MMP19 promotes congenital excavation of the optic disc in CODA. We will test this hypothesis with the following research aims: Aim 1: Test glaucoma patients for MMP19 mutations. We will test a cohort of glaucoma patients for copy number variations, regulatory sequence mutations, and coding sequence mutations in MMP19 with next generation sequencing. Aim 2: Identify the specific enhancer element and transcription factors that regulate MMP19 expression. We will 1) identify the specific DNA sequence of the MMP19 enhancer element via mutagenesis studies and 2) isolate transcription factor(s) that bind to the MMP19 enhancer using a DNA pull down assay and mass spectrometry. This proposal will clarify mechanisms of disease in CODA and provide insights in the process of optic nerve cupping in glaucoma. These investigations may provide the foundation for future studies to develop new sight-saving therapies.