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Open Access Publications from the University of California

Scholarly Works (3 results)

  • Thesis
  • Peer Reviewed
UCLA Electronic Theses and Dissertations (2019)

The goal of biomedical research is first to understand the mechanism of the diseases, then develop a therapy to mitigate such disease. In the process, animal models and in vitro culture systems comprising primary human cells would be utilized as a study platform. An in vitro system representing small intestine is of great interest. However, attempts to develop an in vitro system which accurately reflect the phenotype and function of the human small intestinal epithelium has so far proven unsatisfactory. Hence the accuracy of the experimental results conducted on such systems might be hampered. The goal of this research is to develop an in vitro intestinal epithelium model which accurately recapitulate the human epithelium in vivo.

A natural progression of the epithelial monolayer development was observed in vitro. The morphology of the monolayer went from organized toward disorganized as the cells underwent apoptosis. The innate variabilities among different enterocyte lines which manifested especially in monolayer development were also observed.

Air-Liquid Interface (ALI) culturing condition had proven to have positive effects on monolayer development in vitro. The integrity of the monolayer was able to be maintained up to 14 days due to decreased cellular apoptosis. The enterocytes under ALI condition exhibited increased polarity and adopted columnar morphology which closely resemble the human enterocytes in vivo. The permeability of the ALI cultured monolayer was more physiologically relevant. The ALI condition further demonstrated an effect in enhancing the existing differentiation signal resulted in increased cellular differentiation.

Through co-culture epithelial monolayer with intestinal subepithelial myofibroblast, the cellular apoptosis was further decreased, yielded a well-maintained epithelial monolayer. The additional differentiation signal for goblet cell differentiation was also provided by myofibroblast and was able to be enhanced through ALI culturing condition. It is also confirmed that myofibroblast exerts its effect on intestinal monolayer development via Bone morphogenetic protein (BMP) signaling pathway.

The overall goal of this research was to develop a more physiologically relevant human intestinal epithelium model in vitro. Through combination of ALI culturing condition and co-culture with intestinal subepithelial myofibroblast, a monolayer consisted of polarized, columnar enterocytes with appropriate cellular differentiation was developed.

    Cover page: The Study of Intestinal Epithelial Monolayer Development and Its Interaction with Intestinal Subepithelial Myofibroblast
    • Article
    • Peer Reviewed
    UCLA Previously Published Works (2018)
    Although critical for studies of gut motility and intestinal regeneration, the in vitro culture of intestinal muscularis with peristaltic function remains a significant challenge. Periodic contractions of intestinal muscularis result from the coordinated activity of smooth muscle cells (SMC), the enteric nervous system (ENS), and interstitial cells of Cajal (ICC). Reproducing this activity requires the preservation of all these cells in one system. Here we report the first serum-free culture methodology that consistently maintains spontaneous and periodic contractions of murine and human intestinal muscularis cells for months. In this system, SMC expressed the mature marker myosin heavy chain, and multipolar/dipolar ICC, uniaxonal/multipolar neurons and glial cells were present. Furthermore, drugs affecting neural signals, ICC or SMC altered the contractions. Combining this method with scaffolds, contracting cell sheets were formed with organized architecture. With the addition of intestinal epithelial cells, this platform enabled up to 11 types of cells from mucosa, muscularis and serosa to coexist and epithelial cells were stretched by the contracting muscularis cells. The method constitutes a powerful tool for mechanistic studies of gut motility disorders and the functional regeneration of the engineered intestine.
      Cover page: Bioengineered intestinal muscularis complexes with long-term spontaneous and periodic contractions
      • Article
      • Peer Reviewed
      UCLA Previously Published Works (2018)
      Hutchinson-Gilford progeria syndrome is a disorder of premature aging in children caused by de novo mutations in LMNA that lead to the synthesis of an internally truncated form of prelamin A (commonly called progerin). The production of progerin causes multiple disease phenotypes, including an unusual vascular phenotype characterized by the loss of smooth muscle cells in the arterial media and fibrosis of the adventitia. We show that progerin expression, combined with mechanical stress, promotes smooth muscle cell death. Disrupting the linker of the nucleoskeleton and cytoskeleton (LINC) complex in smooth muscle cells ameliorates the toxic effects of progerin on smooth muscle cells and limits the accompanying adventitial fibrosis.
        Cover page: Disrupting the LINC complex in smooth muscle cells reduces aortic disease in a mouse model of Hutchinson-Gilford progeria syndrome
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