GPR119: A novel means to lower intraocular pressure?

描述（由申请人提供）：GPR 119是一种G蛋白偶联受体，其刺激可增加胰岛素分泌。GPR 119激动剂目前作为治疗II型糖尿病的新疗法处于II期临床试验中。然而，GPR 119在眼睛中的作用尚未被研究。在初步研究中，我们发现GPR 119和候选内源性配体油酰乙醇胺（OEA）和棕榈酰乙醇胺（PEA）都存在于小鼠的前眼中。值得注意的是，GPR 119在小梁网中显著表达，负责房水的流出。初步的功能性实验表明，OEA可使小鼠的眼内压（IOP）降低30%。眼压升高与大多数形式的青光眼相关，青光眼是全球失明的主要原因。我们的研究结果表明，GPR 119为基础的信号系统存在于前眼和GPR 119调节眼内压。该提案将作为三个具体目标来检验这一假设。1)GPR 119受体在小鼠眼中的表达位置？我们将使用免疫细胞化学在小鼠眼的冷冻切片中确定GPR 119的表达模式，并使用GPR 119敲除对照。我们将使用RT-PCR单独评估GPR 119 mRNA表达。2)假定的内源性GPR 119配体存在于小鼠前眼中吗？使用LC-MS，我们将确定小鼠前眼中PEA和OEA的水平和昼夜变化。3)GPR 119激活能降低小鼠模型的眼内压吗？使用Tonolab测量系统，我们将通过测试OEA，PEA和强效合成激动剂AR 231453来扩展初步实验，并以GPR 119敲除动物作为对照。我们还将测试GPR 119介导的IOP降低与基于β-肾上腺素能、α-肾上腺素能和肾上腺素的IOP降低治疗的相互作用。初步结果表明，GPR 119可能是一种全新的降低IOP的方法，对青光眼具有相当大的意义，因此具有很大的治疗潜力。 公共卫生相关性：我们的初步结果为哺乳动物眼睛中基于GPR 119的信号系统提供了强有力的证据，该系统具有受体，配体和功能，其形式为眼内压降低30%。眼压升高与青光眼有关，青光眼导致世界各地数百万人视力受损。因此，鉴定降低眼内压的新途径具有很大的治疗意义。

DESCRIPTION (provided by applicant): GPR119 is a G protein-coupled receptor whose stimulation increases insulin secretion. GPR119 agonists are currently in phase II clinical trials as novel therapeutics for treating type II diabetes. However, the role of GPR119 has not been examined in the eye. In preliminary studies we have found that GPR119 and candidate endogenous ligands oleoylethanolamide (OEA) and palmitoylethanolamide (PEA) are all present in the anterior eye of the mouse. Notably, GPR119 is expressed prominently in the trabecular meshwork, responsible for outflow of aqueous humor. Preliminary functional experiments show that OEA reduces intraocular pressure (IOP) by 30% in the mouse. Elevated IOP is associated with most forms of glaucoma, a major cause of blindness worldwide. Our results suggest that a GPR119-based signaling system is present in the anterior eye and that GPR119 regulates intraocular pressure. The proposal will test this hypothesis as three specific aims. 1) Where are GPR119 receptors expressed in the murine eye? We will determine the expression pattern of GPR119 using immunocytochemistry in frozen sections of mouse eye, with GPR119 knockout controls. We will separately evaluate GPR119 mRNA expression using RT-PCR. 2) Are the putative endogenous GPR119 ligands present in the murine anterior eye? Using LC-MS we will determine the levels and diurnal variation of PEA and OEA in the anterior eye of the mouse. 3) Does GPR119 activation reduce intraocular pressure in a mouse model? Using the Tonolab measurement system we will extend preliminary experiments by testing OEA, PEA, and the potent synthetic agonist AR231453, with GPR119 knockout animals as controls. We will also test the interaction of GPR119-mediated reduction of IOP with beta-adrenergic-, alpha-adrenergic- and prostaglandin-based IOP- lowering treatments. Preliminary results suggest that GPR119 may be an entirely new means of reducing IOP, with considerable implications for glaucoma and therefore of great therapeutic potential. PUBLIC HEALTH RELEVANCE: Our preliminary results provide strong evidence for a GPR119-based signaling system in the mammalian eye, with receptors, ligands and function in the form of a 30% reduction in intraocular pressure. Elevated intraocular pressure is implicated in glaucoma, which causes impaired vision in millions of people around the world. The identification of a novel pathway to lower intraocular pressure is therefore of great therapeutic interest.