Peter van Mourik

68 Chapter 4 SUMMARY This protocol describes the isolation, handling, culture of and experiments with human colon stem cell organoids in the context of cystic fibrosis (CF). In human colon organoids, the cystic fibrosis transmembrane conductance regulator (CFTR) protein function and its rescue by CFTR modulators can be quantified using the forskolin induced swelling assay. Implementation procedures and validation experiments are described for six CF human colon organoid lines, whereby representative CFTR genotypes are tested for basal CFTR function and response to CFTR-modulating drugs. For complete details on the use and execution of this protocol, please refer to Dekkers et al (2016) and Berkers et al (2019). GRAPHICAL ABSTRACT