Dissecting the role of IER3IP1 in neurogenesis and brain malformation

项目摘要 摘要原发性小头畸形是一种结构性出生缺陷，其特征是头部明显较小。 周长大于出生时年龄和性别的平均值。它主要与神经前体细胞功能障碍有关。 细胞数量减少，导致大脑皮层神经元减少。大多数导致小头畸形症的基因是 参与有丝分裂和胞质分裂；然而，最近，分泌蛋白运输的缺陷已经被 与导致小头畸形有关。新发现的可能与蛋白质有关的基因之一 人口贩运是IER3IP1。据报道，IER3IP1的双等位基因变异会导致罕见的，儿科， 神经发育状态称为小头畸形，伴有简单的旋转、全面性癫痫和永久性。 新生儿糖尿病综合征(MEDS)。患有严重先天性结构性脑的MEDS患者 异常，包括小头畸形、脑室增大和脑萎缩。关于IER3IP1的先前研究表明 它的功能涉及到急诊室对高尔基人的贩卖。我确认了致病变异块 通过GFP贩运记者对高尔基体贩运以及IER3IP1突变的纠正 CRISPR/CAS9恢复了贩运效率。在此，我建议重点阐明IER3IP1的功能 在神经发生和人脑发育方面，以了解错误的蛋白质运输是如何导致脑出生的 缺陷。 我推测，IER3IP1在神经发生过程中调节分泌蛋白的运输。我有过 从MEDS中成功制备和鉴定皮质脑器官和2D神经元培养 患者来源的诱导多能干细胞和同基因对照细胞来测试这一点。使用这些药物的患者 细胞模型，我将完成以下目标：目标1.小头畸形的潜在细胞机制是什么 在带有IER3IP1 p.L78P突变的药物患者中发现？和目的2.IER3IP1是否调节分子 膜受体的运输对神经发育很重要？这项建议将填补我们在这方面的空白 了解蛋白质运输如何调节神经发生，并提供对异常蛋白质如何 贩卖人口会导致大脑结构异常。

Project Summary Primary microcephaly is a structural birth defect characterized by a significantly smaller head circumference than the mean of age and gender at birth. It is mainly linked to dysfunction of the neural progenitor cell population, resulting in reduced neurons in the cerebral cortex. Most microcephaly-causing genes are involved in mitosis and cytokinesis; however, recently, defects in secretory protein trafficking have been implicated in causing microcephaly. One of the newly identified genes that are potentially involved in protein trafficking is IER3IP1. Bi-allelic variants of IER3IP1 have been reported to cause a rare, pediatric, neurodevelopmental condition called microcephaly with simplified gyration, generalized epilepsy, and permanent neonatal diabetes syndrome (MEDS). MEDS patients present with severe congenital structural brain abnormalities, including microcephaly, ventriculomegaly, and cerebral atrophy. Prior studies on IER3IP1 suggest that its function is involved in ER to the Golgi trafficking in humans. I confirmed that the pathogenic variant blocks ER to Golgi trafficking with a GFP trafficking reporter, and the correction of IER3IP1 mutation through CRISPR/Cas9 restored the trafficking efficiency. Herein, I propose to focus on elucidating the function of IER3IP1 in neurogenesis and human brain development to understand how faulty protein trafficking leads to brain birth defects. I hypothesize that IER3IP1 regulates secretory protein trafficking during neurogenesis. I have successfully generated and characterized cortical brain organoids and 2D neuronal culture derived from MEDS patient-derived induced pluripotent stem cells and isogenic control cells to test this. Using these MEDS patient cell models, I will complete the following aims: Aim 1. What is the underlying cellular mechanism of microcephaly seen in MEDS patients with IER3IP1 p.L78P mutation? and Aim 2. Does IER3IP1 regulate the molecular trafficking of membrane receptors important in neurodevelopment? This proposal will fill the gap in our understanding of how protein trafficking regulates neurogenesis and provide insight into how abnormal protein trafficking leads to structural brain abnormalities.