Establishment of a Human Colon Epithelial Cell Culture System to Study their Regulating Effects on Resident Lamina Propria Immune Cell Activation

The intestinal epithelial layer represents an important barrier between luminal microbes, toxins and antigens on one side, and lamina propria immune cells on the other side. We have shown that loss of the epithelium leads to the initiation of an inflammatory response in resident lamina propria immune cells. To study heterotypic cell interactions between epithelium and lamina propria in the intestine, we began to establish an ex-vivo co-culture system. To this end, crypts, which include the epithelial stem cells, were isolated from healthy human primary colonic mucosa and embedded in Matrigel according to the previously published method of Sato et al. 2009. Individual organoid structures grew in size and developed several extending buds representing a multi-crypt structure. Within these buds the proliferation marker Ki67 was detected. The intestinal stem cells in the buds gave rise to differentiated crypts showing the upregulation of markers representative of epithelial cell differentiation. For the co-culture of epithelial cells and lamina propria immune cells, a Transwell system will be established based on a collagen-matrix obtained from decellularized porcine small intestine as generated in the laboratory of H. Walles. The system will be used to study the role of the epithelium in the control of initial inflammatory responses of lamina propria immune cells.