Abstract
Background
Intestinal fibrosis is a serious complication of inflammatory bowel disease (IBD) with > 20% of Crohn’s disease patients developing this complication within 10 years of diagnosis. Despite improvements in anti-inflammatory medication, its incidence remains stubbornly high and thus far surgical intervention remains the only treatment option. Numerous cell types including intestinal epithelial and mesenchymal cells are implicated in this process, yet studies are hampered by the lack of personalized in vitro models. One potential avenue that would permit a personalized approach is to utilize human intestinal organoids (HIOs) derived from induced pluripotent stem cells (iPSCs). iPSCs can be generated from any individual, faithfully recapitulate the genetics of the host and can be directed to form HIOs that contain both epithelial and mesenchymal cells. Our goal was to determine the feasibility of utilizing iPSC-HIO technology to model intestinal fibrotic responses in vitro.
Methods
iPSCs from two control individuals and two very early onset-IBD (VEOIBD) patients with stricturing complications were obtained and directed to form HIOs. Given HIOs are heterogeneous in terms of size, shape and ratio of mesenchymal to epithelial cells, they were firstly dissociated to a single cell suspension and EpCAM was used to positively select for epithelial cells using magnetic activated cellular sorting. These EpCAM+ cells were then seeded onto transwells and EpCAM- cells were seeded as monolayers in 10% serum containing media. Both cell types were treated with the profibrotic cytokine TGFβ, and changes in the expression of selected genes were analyzed.
Results
iPSCs from all 4 individuals could be directed to form HIOs containing both epithelial (E-cadherin+) and mesenchymal (vimentin+) cells (see Fig. 1). In the TGFβ-treated mesenchymal cell population, expression of N-cadherin and Col1a1 was significantly increased in all four lines after 8 and 48hrs respectively, with the highest increase occurring in cells derived from VEOIBD patient 2 (see Table 1). In the TGFβ-treated epithelial cell population, Col1a1 and fibronectin expression was increased in all lines after 96hrs with the highest fold change occurring in cells derived from VEOIBD patient 1 (fibronectin) and 2 (Col1a1).
Conclusion
We demonstrate the feasibility of utilizing iPSC-HIO technology to model intestinal fibrotic responses in vitro. We show that iPSCs generated from all selected individuals could be directed to form HIOs and that responses to the profibrotic cytokine TGFβ can be examined in both intestinal epithelial and mesenchymal cells. This now permits the generation of near unlimited quantities of patient specific cells that could be used to reveal cell and environmental specific mechanisms underpinning intestinal fibrosis which may ultimately lead to personalized treatments.
Fluorescent images of human intestinal organoids generated from A) Control 1, B) Control 2, C) VEOIBD patient 1 and D) VEOIBD patient 2 that were immunostained with vimentin (green), E-cadherin (red) and counterstainied with DAPI (blue). All images X20
Development of a Personalized Intestinal Fibrosis Model Using Human Intestinal Organoids Derived From Induced Pluripotent Stem Cells
