Differentiation of intestinal epithelial cells mediated by cell confluence and/or exogenous nucleoside supplementation

Abstract

Nucleotides (NT) and nucleosides (NS) play a key role in gastrointestinal development and in enterocyte healing after tissue damage. Exogenous NT and NS may therefore represent a novel therapy for maintaining gastrointestinal tract integrity. An exogenous NS mixture of thymidine, cytidine, guanosine and inosine (T-CGI) increases the proliferation rate of rat intestinal epithelial cell line 6 (IEC-6) cells, while a mixture of uridine, cytidine, guanosine and inosine (U-CGI) reduces IEC-6 proliferation independently of necrosis or apoptosis. This study aimed to analyze the effects of exogenous NS on IEC-6 differentiation under proliferation and differentiation conditions. To this end, IEC-6 cells were treated with NS T-CGI and NS U-CGI mixtures under low- and high-density conditions. Enterocyte differentiation was also assessed by flow cytometry, Western blotting, and light, fluorescence and transmission electron microscopy. Under proliferative conditions, villin expression was reduced in all cases, but NS-treated cells showed twofold the expression observed in NS-free cultures (controls) and more frequently showed characteristics of mature enterocytes. When cells were grown after confluence, villin expression, total protein production and morphology of NS-treated cultures were more differentiated compared with the control group. Our results demonstrate that T-CGI and U-CGI mixtures promote IEC-6 cell differentiation, with no significant differences between them. Unlike previous authors, we obtained this effect in cultures without an exogenous extracellular matrix such as Matrigel, reducing the variability among independent assays.