Schlafen 3 Mediates the Differentiating Effects of Cdx2 in Rat IEC-Cdx2L1 Enterocytes.

Aim: Mature, differentiated enterocytes are essential for normal gut function and critical to recovery from pathological conditions. Little is known about the factors that regulate intestinal epithelial cell differentiation in the adult intestine. The transcription factor, Cdx2, involved in enterocytic differentiation, remains expressed in the adult. Since we have implicated Slfn3 in differentiation in vivo and in vitro, we examined whether it also mediated differentiation in the IEC-Cdx2-L1 cell model of differentiation.

Materials And Methods: IEC-Cdx2-L1 cells, permanently transfected with Cdx2 under the control of isopropyl-β-D-thiogalactoside (IPTG), were stimulated to differentiate by 16-day exposure to IPTG. Transcript levels of Cdx2, Slfn 3, and villin were determined by quantitative reverse transcriptase-polymerase chain reaction of mRNA isolated from IPTG-treated and control cells. Slfn3 expression was lowered with specific siRNA to investigate the role of Slfn3 in Cdx2-driven villin expression in IPTG-differentiated cells.

Results: Slfn3 and villin expression were significantly greater in IPTG-treated cells. Slfn3 siRNA lowered Slfn3 expression and abolished the IPTG-induced rise in villin expression (p < .05 by ANOVA); Cdx2 expression was unaffected by Slfn3 siRNA.

Discussion: The data indicate that the presence of Slfn3 is required for Cdx2 to induce villin expression, and thus differentiation. However, Slfn3 must also promote differentiation of Cdx2 independently since IEC-6 cells that do not normally express Cdx2 can be differentiated by a variety of Slfn3-dependent mechanisms.