Stimulation of human colonic epithelial cells by leukemia inhibitory factor is dependent on collagen-embedded fibroblasts in organotypic culture

Abstract

The colonic epithelium undergoes a continuous cycle of proliferation, differentiation, and apoptosis. To characterize factors important for colonic homeostasis and its dysregulation, human fetal colonic epithelial cells were isolated and seeded on a collagen type I matrix with embedded colonic fibroblasts. The epithelial cells rapidly spread from clusters and proliferated, and within 3 days, a columnar layer of polarized epithelium surrounded the surface of the constricted collagen matrix. The polarized enterocytes developed brush borders, tight junctions and desmosomes, and goblet and enteroendocrine cells were present. A balance of growth and differentiation was maintained for several weeks in the presence of collagen-embedded fibroblasts and a complex mixture of growth factors. Leukemia inhibitory factor (LIF) was critical for proliferation of enterocytes and inhibited expression of the differentiation marker carbonic anhydrase II. In the presence of LIF, the relative number of goblet cells remained stable, whereas enteroendocrine relative cell number declined. LIF-stimulated epithelial cells remained dependent on the presence of fibroblasts in the matrix. In combination with stem cell factor and endothelin 3, LIF induced formation of disorganized structures of stratified and semi-stratified cells, suggesting that the homeostatic balance in the normal human colon requires cooperation with differentiation-inducing factors.