Different responses of Fe transporters in Caco-2/HT29-MTX cocultures than in independent Caco-2 cell cultures

The human intestinal epithelium is composed of several cell types, mainly enterocytes and goblet (mucin-secreting) cells. This study compares the cellular response of Fe transporters in Caco-2, HT29-MTX, and Caco-2/HT29-MTX co-culture models for Fe bioavailability. Caco-2 cells in vitro differentiate into enterocyte-like cells and HT29-MTX cell lineage into a mucin-secreting cellular population. Cell cultures were exposed to digests of Fe+3, Fe+3/ascorbic acid, cooked fish (high-available Fe) or white beans (low-available Fe). Cell responses as shown by mRNA expression of the main Fe transporters, DMT1 and DcytB, and cell ferritin formation were monitored. In Caco-2/HT29-MTX co-cultures, the mucin layer lowered the pool of free Fe to diffuse towards the cell brush border membrane of enterocytes, which was accompanied of an upregulation of DMT1 mRNA expression. In contrast, cultures exposed to digests of fish or white beans showed no significant differences in the regulation of Fe transporters.