Organoid culture media containing growth factors of defined cellular activity

The media components necessary for deriving and sustaining organoids from a number of epithelial tissues such as prostate, colon, gastric, liver, pancreas, and others have been established (1). Critical components of organoid media formulations are a set of growth factors that include EGF, R-spondins and BMP signalling antagonists such as Noggin or Gremlin. The practical limitation to organoid culture and the development of new applications for the technology is the use of defined cellular activities of growth factors in media formulations, in particular Noggin/Gremlin 1 and R-spondin 1. Here we report the production of highly pure recombinant Gremlin 1 and R-spondin 1 from bacterial expression and their use for culturing organoids. We detail the workflow for their purification, determination of cellular activity, quality control and their formulation in organoid media. The protocols we provide for generation of precisely formulated, cost-effective, organoid media of defined cellular activity will enable broader access to organoid technology and engender the development of novel applications.