IPEC-J2 as a cellular model for studying intestinal mucus

Mucus in the proximal small intestine serves critical protective and transport functions, regulating nutrient absorption to enterocytes. The porcine jejunal epithelial cell line IPEC-J2 is widely used to study epithelial barrier function, yet its capacity to express mucins remains inconsistently described. This study aimed to investigate the ability of IPEC-J2 cells to express mucins under various culture conditions: 5% or 10% porcine serum (5PS, 10PS), with agitation (5PSAg and 10PSAg) and air-liquid interface (ALI). Mucus production was assessed using functional and structural approaches. Expression of secreted mucin MUC2 and goblet cell marker TFF3 was limited under most conditions but markedly enhanced in ALI and 5PSAg cultures. Immunohistochemistry revealed membrane-associated mucins (MUC3, MUC13) although MUC13 localisation differed between IPEC-J2 and jejunal tissue. Flow cytometry revealed that ~ 8% of IPEC-J2 cells expressed MUC2 in 5PSAg, comparable to the proportion of jejunum's goblet cells in vivo (~ 5%). This study demonstrated that IPEC-J2 cells can differentiate into mucus-secreting cells under specific culture conditions, and they are a suitable in vitro model for investigating interactions between mucus and food components, providing a valuable tool for nutritional research.