Novel intestinal stem cell culture system

In vitro expansion and genetic modification of gastrointestinal stem cells in spheroid culture

It is useful to be able to grow enriched populations of stem cells in vitro. Growth of stem cells as tissue spheroids is a key methodology permitting sustainable culture of adult epithelial cells. Gastrointestinal stem cells can be propagated by using conditioned medium from a supportive cell line (L-WRN). This protocol describes how to prepare conditioned medium and how to culture stem cell-enriched epithelial spheroids from the mouse gastrointestine. These spheroids are also amenable to genetic modification with recombinant lentiviruses. This system enables many types of cell biological assays that have been performed with immortalized cell lines to be applied to spheroids. Isolation of epithelial cell units from mice takes up to 2 h, and stem cell-enriched gastrointestinal spheroids are obtained within 3 d. Genetically modified spheroids with lentiviruses can be obtained in 2 weeks.

Intestinal organoids as tissue surrogates for toxicological and pharmacological studies

Recently developed cell culture protocols have allowed for the derivation of multi-cellular structures dubbed intestinal "organoids" from embryonic stem cells (ESCs), induced pluripotent stem cells (IPSCs), and adult intestinal stem cells (ISCs). These structures resemble in vivo intestinal crypts, both in structure and developmental processes, and can be grown quickly and in relatively large quantities. Although much research has focused on developing intestinal organoids for tissue repair, more immediate applications include high-throughput screening for agents that target intestinal epithelium. Here we describe current methods for deriving mouse and human intestinal organoids and discuss some applications aimed at developing novel therapies or preventive agents for diseases of the lower GI tract such as inflammatory bowel diseases and colorectal cancer.