Fig. 1

Functions of goblet cells. Goblet cells have several functions which are directly or indirectly related to Crohn’s disease: ① Mucus secretion: goblet cells secret and renew the mucus layer at a steady turnover rate. This secretion process also pushes most pathogenic bacteria away from approaching the enterocytes. ② Mucin secretion: goblet cells secret mucins which have binding sites for bacteria. Mucins play a vital role in anti-pathogenic bacteria invasion. ③ Mucus-Microbiome Interactions: Bacteria take substance in the mucus as energy source for their growth and affect the mucus secretion. Mucus determines the microbiome constitution in gut. ④ Interaction with the immune system: goblet cells are involved in antigen presentation process, and they also secret cytokines, interfering the immune system