LPA and LPA4 receptors in retinal axon guidance in the developing visual system

眼部疾病和视力丧失是美国和世界范围内的一个主要医学问题。青光眼是导致失明的第二大原因，原因是视网膜神经节细胞（RGCs）和视神经受损。视神经不能自然再生，导致永久性残疾。我们的长期目标是开发能够诱导RGC再生以恢复视力的疗法。我们的方法是分析RGC轴突和视神经在神经自然生长期间的正常发育，以获得再生治疗的线索。为了实现这一目标，我们正在研究引导RGC轴突到达正确目标的分子。具体来说，我们正在分析一类新的信号分子，溶血磷脂，特别是溶血磷脂酸（LPA）的作用。我们假设LPA通过同源受体LPA4起作用，是视网膜神经节细胞（RGC）轴突发育过程中的引导分子。我们提出通过三个具体目的来验证这一假设：(1)通过确定LPA4受体在视网膜发育过程中的时空表达，(2)通过siRNA敲低确定LPA4受体在体外介导轴突引导中的作用，以及(3)通过确定LPA和LPA4受体在发育中的鸡体内介导RGC轴突引导的作用。此外，这项调查将被用作指导温斯洛普大学本科生的工具，在教授分析技能和对科学过程的理解的同时，培养下一代科学家。

DESCRIPTION (provided by applicant): Ocular disease and vision loss is a major medical problem in the US and worldwide. Glaucoma is the second leading cause of blindness due to damage to Retinal Ganglion Cells (RGCs) and the optic nerve. The optic nerve does not naturally regenerate, which results in permanent disability. Our long-term goal focuses on developing therapies to induce RGC regeneration to restore sight. Our approach is to analyze the normal development of RGC axons and the optic nerve during the time when nerve growth occurs naturally in order to obtain clues for regenerative therapy. Toward this goal, we are investigating the molecules that guide RGC axons to their correct targets. Specifically, we are analyzing the role of a novel class of signaling molecules, the lysophospholipids, specifically lysophosphatidic acid (LPA). We postulate that LPA, acting through the cognate receptor LPA4, is a guidance molecule for retinal ganglion cell (RGC) axons during development. We propose to test this hypothesis through three specific aims: (1) by determining the spatial and temporal expression of LPA4 receptors in retinal development, (2) by determining the role of LPA4 receptors in mediating axon guidance in vitro through siRNA knockdown, and (3) by determining the role of LPA and LPA4 receptors in mediating RGC axon guidance in vivo in the developing chick. Furthermore, this investigation will be used as a tool to mentor undergraduate students at Winthrop University, developing the next generation of scientists while teaching analytical skills and an understanding of the scientific process.