Transwell-cultured and miRNAs-transfected T84 cells

MicroRNAs are small non-coding RNA species, some of which are playing important roles in cell differentiation. However, the level of participations of microRNAs in epithelial cell differentiation is largely unknown. Here, we found that expression levels of four microRNAs (miR-210, miR-338-3p, miR-33a and miR-451) were significantly increased in differentiated stage of T84 cells, compared with undifferentiated stage. Additionally, we demonstrate that miR-338-3p and miR-451 contribute to the formation of epithelial basolateral polarity by facilitating translocalization of beta1 integrin to the basolateral membrane. However, candidate target mRNAs of miR-338-3p and miR-451 and the mechanism behind observed phenomena is uncertain. Then, we performed comprehensive gene expression analysis to identify candidate target mRNAs and understand their mechanisms. T84 cells were seeded in transwell chambers and were transfected with microRNAs. Total RNA was extracted by the acid guanidinium thiocyanate-phenol-chloroform method, and was labeled and prepared for hybridization to GeneChip Human Genome U133 Plus 2.0 arrays (Affymetrix) according to the manufacture’s instructions (standard protocol).