Integrin-activating Yersinia protein Invasin sustains long-term expansion of primary epithelial cells as 2D organoid sheets.

Matrigel ^® /BME ^® , a basement membrane-like preparation, supports long-term growth of epithelial 3D organoids from adult stem cells [T. Sato et al. , Nature 459 , 262-265 (2009); T. Sato et al. , Gastroenterology 141 , 1762-1772 (2011)]. Here, we show that interaction between Matrigel's major component laminin-111 with epithelial α6β1-integrin is crucial for this process. The outer membrane protein Invasin of Yersinia is known to activate multiple integrin-β1 complexes, including integrin α6β1. A C-terminal integrin-binding fragment of Invasin, coated on culture plates, mediated gut epithelial cell adhesion. Addition of organoid growth factors allowed multipassage expansion in 2D. Polarization, junction formation, and generation of enterocytes, goblet cells, Paneth cells, and enteroendocrine cells were stable over time. Sustained expansion of other human, mouse, and even snake epithelia was accomplished under comparable conditions. The 2D "organoid sheet" format holds advantages over the 3D "in gel" format in terms of imaging, accessibility of basal and apical domains, and automation for high-throughput screening. Invasin represents a fully defined, affordable, versatile, and animal-free complement to Matrigel ^® /BME ^® .
Competing Interests: Competing interests statement:H.C. is an inventor on patents held by the Royal Netherlands Academy of Arts and Sciences that cover organoid technology and a co-founder of Xilis, Duke University (NC). He is currently Head of pharma Research and Early Development (pRED) at Roche, Basel Switzerland. J.J.A.P.M.W., W.d.L., and H.C. are inventors on a patent application directly related to this study. The other authors declare no conflicts of interest., Yes, the authors have research support to disclose, Supported by the Gravitation project Material Driven Regeneration (024.003.013 ZWK MDR) from the Netherlands Organization for Scientific Research (NWO) funded by the Ministry of Education, Culture and Science of the government of the Netherlands (J.J.A.P.M.W., W.d.L., D.K., H.C.) and the Oncode Institute (partly financed by the Dutch Cancer Society (H.C.). H.C. is currently head of Pharma Research and Early development at Roche.