Skip to Main Content
 

Global Search Box

 
 
 
 

Files

ETD Abstract Container

Abstract Header

Mechanisms of endoderm patterning and directed differentiation of human stem cells into foregut tissues

McCracken, Kyle W

Abstract Details

2014, PhD, University of Cincinnati, Medicine: Molecular and Developmental Biology.
A number of organs derive from the embryonic foregut, including the lungs, stomach, pancreas, liver, and esophagus, and they collectively have an overwhelming impact on human health and disease. Although human pluripotent stem cells (hPSCs) hold great promise as a limitless source of material that could potentially treat disease, there is currently a paucity of efficient methods to differentiate them into functional foregut tissues in vitro. In the embryo, the early endoderm is patterned into discrete progenitor domains along the A-P and D-V axes, and each organ is then specified from a highly stereotypic location in the gut tube. We hypothesized that the major deficiencies associated with hPSC differentiation protocols are due to the significant gaps in our understanding of the molecular mechanisms of early endoderm patterning and the resulting inability to robustly recapitulate these events in vitro. Further, most published protocols utilize flat culture systems and thus lack complex three-dimensional morphogenesis that is critical for organ formation in vivo. Here we report the de novo generation of organized, three-dimensional foregut epithelia for the first time, and we show that they are competent to differentiate into complex organ tissues that achieve an unprecedented degree of maturation in vitro. We identified novel interactions between WNT, FGF, BMP, and RA signaling pathways that are responsible for patterning the endoderm into distinct foregut domains and promoting the three-dimensional organization of endoderm and mesoderm into gut tube spheroids. We then used RA to promote the specification of posterior foregut spheroids into the gastric lineage, which caused the spheroids to grow and develop into human gastric organoids (hGOs). The hGOs recapitulated the normal molecular and morphogenetic stages of in vivo gastric development, ultimately forming an elaborate glandular epithelium containing a complex array of gastric cell types. The hGOs only contained epithelia found in the distal stomach, or antrum, so we then used this model to investigate human stomach development and identified a novel function of WNT signaling in gastric patterning. Activation of Wnt/ß-catenin at early stages promoted the specification of the more proximal stomach, the fundus, and the generation of fundic hGOs. Furthermore, we used hGOs as a new model of human disease by infecting them with the gastric pathogen Helicobacter pylori, which resulted in rapid changes in epithelial signaling and proliferation. In summary, these studies describe a novel and robust in vitro system for elucidating the mechanisms of foregut organ development and generating tissues to develop new models to investigate human physiology and disease.
James Wells, Ph.D. (Committee Chair)
Noah Shroyer, Ph.D. (Committee Member)
Jeffrey Whitsett, M.D. (Committee Member)
Yana Zavros, Ph.D. (Committee Member)
Aaron Zorn, Ph.D. (Committee Member)
184 p.

Recommended Citations

Citations

  • McCracken, K. W. (2014). Mechanisms of endoderm patterning and directed differentiation of human stem cells into foregut tissues [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406819241

    APA Style (7th edition)

  • McCracken, Kyle. Mechanisms of endoderm patterning and directed differentiation of human stem cells into foregut tissues. 2014. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406819241.

    MLA Style (8th edition)

  • McCracken, Kyle. "Mechanisms of endoderm patterning and directed differentiation of human stem cells into foregut tissues." Doctoral dissertation, University of Cincinnati, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406819241

    Chicago Manual of Style (17th edition)