Zinc (Zn) is a mineral, taken up from the food. Zn deficiency is related to intestinal infections and sepsis. Zn addition has been found to have therapeutic effects in animals and humans. However, the mechanism is not known. It is thought that Zn modulates the composition of the gut microbiome, by modulating gene expression in the intestinal epithelial cells (IECs). Our work hypothesis is that Zn stimulates antimicrobial pathways in the most specialized cells of the IECs, the Paneth cells (PCs). PCs store Zn and respond to it, but the lack of sufficient amounts of PCs has hampered their detailed study so far. We have decided that the generation of an immortalized PC line (iPCL) would be a tremendous step forward, to study the effects of Zn, but also to develop an assay system, to screen for molecules which have a Zn-like effect, and could help to reduce the necessary dose of Zn that should be provided to patients and animals. This is important because Zn is a heavy metal and should not cause environmental contamination. With my project, I will make ample use of our PC-specific cre-mice and use them to purify PCs and immortalize them. Once the iPCL is there, I will study the impact of Zn on transcriptomics and proteomics. Third, I will develop a screening assay, and screen a custom compound library and a larger discovery library. Finally, I will evaluate the possibility to identify in mouse feces, a PC biomarker that might reflect the amount and/or secretion status of PCs.