An Adaptable Protocol to Generate a Murine Enteroid-Macrophage Co-Culture System

Impairment of the intestinal epithelial barrier is frequently seen as collateral damage in various local and systemic inflammatory conditions. The inflammatory process is characterized by reciprocal interactions between the host intestinal epithelium and mucosal innate immune cells, e.g., macrophages. This article provides step-by-step instructions on how to set up a murine enteroid-macrophage co-culture by culturing cellular elements in proximity separated by a porous membrane. Unlike previously published co-culture systems, we have combined enteroids grown from C57BL6j mice with syngeneic bone marrow-derived macrophages to preclude potential allo-reactions between immune cells and epithelium. Transformation of intestinal crypts into proliferative enteroids was achieved by cultivation in Wnt3a-Noggin-R-Spondin-conditioned medium supplemented with ROCK inhibitor Y-27632. The differentiated phenotype was promoted by the use of the Wnt3-deprived EGF-Noggin-R-Spondin medium. The resulting co-culture of primary cells can be employed as a basic model to better understand the reciprocal relationship between intestinal epithelium and macrophages. It can be used for in vitro modelling of mucosal inflammation, mimicked by stimulation of macrophages either while being in co-culture or before being introduced into co-culture, to simulate enterogenic sepsis or systemic conditions affecting the intestinal tract.