Preventing hyperphagia in Prader Willi syndrome using an oligonucleotide

描述（由申请人提供）：Prader-Willi综合征（PWS）中最严重的日常问题之一是餐后无法达到饱腹感，这会导致食欲过盛和肥胖。两个小核仁RNA（snoRNA）簇表达的缺失是该疾病的关键遗传因素。其中一种snoRNA（SNORD 115）促进最活跃的5-羟色胺受体2C（HTR 2C）。弓状核中激活的HTR 2C受体抑制食物摄取。我们开发了与SNORD 115类似的寡核苷酸（“oligo#5”），其促进定位于细胞表面上的最具活性的HTR 2C受体的形成。当通过脑室内（ICV）或颈动脉注射递送至弓状核时，寡核苷酸#5抑制禁食小鼠的食物摄取。我们推测oligo#5可能被开发成一种治疗Prader-Willi综合征的抗暴食药物。这一假设将在两个具体目标中进行检验：1.将oligo#5及其衍生物递送至脑中的弓状核并确定其作用模式。我们将测试使用渗透泵将寡核苷酸#5带入第三脑室的递送，类似于急性注射。寡核苷酸#5在下丘脑中积累，并在颈动脉注射后减少食物摄取，表明它可以穿过血脑屏障。因此，我们将通过注射到血液中来测试分娩。在小鼠中测试之前，将在基于细胞的模型中测试寡核苷酸#5的不同化学性质。这允许确定功效并获得机械见解。2.确定寡核苷酸的长期毒性、功效和非位点靶点。我们在多达三次重复注射中没有观察到不良反应，并将使用渗透泵和注射到血液中测试长期递送。我们将确定免疫反应，行为变化，炎症和其他不良反应，并测量疗效随时间的变化。脱靶效应将通过RNA测序和阵列分析进行测量。我们预计oligo#5是安全的，可以通过血液输送，并显示长期减少食物摄入。这些研究是重要的，因为它们针对患者日常生活中最复杂的特征--暴食症，它们是创新的，因为它们可能通过血液将核酸递送到大脑区域，在那里它通过改变靶RNA加工而起作用;它们是可行的，因为我们开发了寡核苷酸和检测系统。

DESCRIPTION (provided by applicant): One of the most severe daily problems in Prader-Willi syndrome (PWS) is the inability to reach satiety after a meal, which leads to hyperphagia and obesity. The loss of expression of two small nucleolar RNA (snoRNA) clusters is a crucial genetic contributor to the disease. One of these snoRNAs (SNORD115) promotes the most active form of the serotonin receptor 2C (HTR2C). Activated HTR2C receptors in the arcuate nucleus inhibit food uptake. We developed an oligonucleotide ("oligo#5") that similar to SNORD115 promotes the formation of the most active HTR2C receptor that localizes on the cell surface. Oligo#5 inhibits food uptake of fasted mice when delivered by intracerebroventricular (ICV) or carotid injection to the arcuate nucleus. We postulate that oligo#5 could be developed into an anti hyperphagia drug for Prader-Willi syndrome. This hypothesis will be tested in two Specific Aims: 1. Deliver oligo#5 and its derivatives to the arcuate nucleus in the brain and determine their mode of action. We will test delivery using osmotic pumps bringing oligo#5 into the 3rd ventricle, similar to the acute injections. Oligo#5 accumulates in the hypothalamus and decreases food uptake after carotid injection, suggesting it can cross the blood brain barrier. We will therefore test delivery by injecting into the bloodstream. Different chemistries of oligo#5 wil be tested in cell-based models prior to testing in mice. This allows to determine efficacy and to get mechanistic insights. 2. Determine long term toxicity, efficacy and off-site targets of the oligonucleotide. We did not observe adverse effects in up to three repeated injections and will test long-term delivery using osmotic pumps and injection into the blood. We will determine immune response, behavioral changes, inflammation and other adverse effects and measure changes in efficacy over time. Off-target effects will be measured by RNA sequencing and array analysis. We expect that oligo#5 is safe, can be delivered through the bloodstream and shows a long-term reduction in food intake. These investigations are significant, as they target hyperphagia, the most complicating feature in the daily lives of patients, they are innovative as they deliver a nucleic acid to a brain region possibly through the blood, where it acts by changing target RNA processing; they are feasible, as we developed the oligonucleotide and the detection system.