The Role of GATA3 and SATB2 in Early Colonic Patterning

后肠引起结直肠和尿路上皮/膀胱病变。这两代人

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.