The Role of GATA3 and SATB2 in Early Colonic Patterning

后肠导致结直肠和尿路上皮/膀胱结局。这两代人 命运需要后肠的分割。后肠的不适当分割导致 肛门直肠畸形我们已经产生了一个强大的新的体外模型， 从人诱导多能干细胞产生结肠直肠和尿路上皮类器官 细胞（IPSC）通过骨形态发生蛋白（BMP）信号转导的瞬时激活。 使用这种体外模型，我们已经将WNT信号传导确定为一种关键的外在信号， 指定尿路上皮祖细胞并抑制结肠直肠祖细胞。此外，使用 通过CRISPR-Cas9介导的人IPSC的编辑，我们发现尿路上皮特化是一个非常重要的过程。 在GATA 3缺陷细胞中受到干扰。基于这些观察，我们制定了 假设两种发育途径BMP和WNT会聚以诱导 GATA 3的表达，其随后抑制尿路上皮祖细胞中的CDX 2。 该假设将在2个特定目标中进行检验： 目的1：确定BMP和WNT信号在骨肉瘤中的协同作用机制。 GATA 3在尿路上皮中的活化。 目的2：确定CDX 2在肿瘤细胞中被抑制的分子机制。 尿道炎 使用我们的结肠直肠和尿路上皮分化的体外模型，我们将确定BMP如何 和WNT信号传导会聚以诱导GATA 3的表达。此外，我们将确定， GATA 3通过抑制CDX 2驱动尿路上皮特化。这些研究将 阐明后肠分配的关键机制，这将使发展 改进的结肠和尿路上皮类器官，其可用于疾病建模和 器官置换

The hindgut gives rise to colorectal and urothelial/bladder fates. The generation of these 2 fates requires the partitioning of the hindgut. Improper partitioning of the hindgut causes anorectal malformations. We have generated a powerful new in vitro model that allows for the generation of both colorectal and urothelial organoids from human induced pluripotent stem cells (IPSCs) through the transient activation of Bone Morphogenetic Protein (BMP) signaling. Using this in vitro model, we’ve identified WNT signaling as a critical extrinsic signal that specifies urothelial progenitors and represses colorectal progenitors. In addition, using CRISPR-Cas9 mediated editing of human IPSCs, we found that urothelial specification is perturbed in GATA3 deficient cells. Based on these observations we formulated the hypothesis that two developmental pathways, BMP and WNT, converge to induce expression of GATA3 which subsequently represses CDX2 in urothelial progenitors. This hypothesis will be tested in 2 specific aims: Aim 1: Determine the mechanism of cooperative BMP and WNT signaling in the activation of GATA3 in the urothelium . Aim 2: Determine the molecular mechanisms through which CDX2 is repressed in the urothelium. Using our in vitro model of colorectal and urothelial differentiation, we will determine how BMP and WNT signaling converge to induce expression of GATA3. In addition, we will determine if GATA3 drives urothelial specification through the inhibition of CDX2. These studies will elucidate key mechanisms of hindgut partitioning which will enable the development of improved colonic and urothelial organoids which can be used for disease modeling and for organ replacement.