Investigation of Musashi-1 expressing cells in the murine model of dextran sodium sulfate-induced colitis.

Musashi-1 (Msi-1), an RNA-binding protein, had been proposed to be a specific marker for neural stem/precursor cells. Msi-1 expressing cells in the intestinal epithelium are also strongly considered as potential stem/precursor cells. To clarify the behavior of those cells in the injury or regeneration phase, we investigated Msi-1 expressing cells of intestinal mucosa in the murine model of dextran sodium sulfate (DSS)-induced colitis. Immunohistochemically, Msi-1-positive cells were found in the area just along the layer of Paneth's cells in the small intestine and in the bottom layer of crypts in the large intestine. During DSS administration, the number of PCNA-positive cells in the large intestine increased markedly. In contrast, the number of Msi-1-positive cells decreased slightly with DSS but returned to normal after DSS administration was stopped. The level of mRNA for Msi-1 was consistent with the result of immunohistochemical examinations. Conclusively, we could describe the behavior of intestinal stem/precursor cells during inflammation using Msi-1.