Aims: MicroRNAs are a class of small noncoding RNAs, which control gene expression by inhibition of mRNA translation. MicroRNAs are involved in the control of biological processes including cell differentiation. Here, we aim at characterizing microRNA expression profiles during differentiation of human induced pluripotent stem cells (hiPSCs) into insulin-producing cells.
Methods: We differentiated hiPSCs toward endocrine pancreatic lineage following a 18-day protocol. We analyzed genes and microRNA expression levels using RT real-time PCR and TaqMan microRNA arrays followed by bioinformatic functional analysis.
Results: MicroRNA expression profiles analysis of undifferentiated hiPSCs during pancreatic differentiation revealed that 347/768 microRNAs were expressed at least in one time point of all samples. We observed 18 microRNAs differentially expressed: 11 were upregulated (miR-9-5p, miR-9-3p, miR-10a, miR-99a-3p, miR-124a, miR-135a, miR-138, miR-149, miR-211, miR-342-3p and miR-375) and 7 downregulated (miR-31, miR-127, miR-143, miR-302c-3p, miR-373, miR-518b and miR-520c-3p) during differentiation into insulin-producing cells. Selected microRNAs were further evaluated during differentiation of Sendai-virus-reprogrammed hiPSCs using an improved endocrine pancreatic beta cell derivation protocol and, moreover, in differentiated NKX6.1+ sorted cells. Following Targetscan7.0 analysis of target genes of differentially expressed microRNAs and gene ontology classification, we found that such target genes belong to categories of major significance in pancreas organogenesis and development or exocytosis.
Conclusions: We detected a specific hiPSCs microRNAs signature during differentiation into insulin-producing cells and demonstrated that differentially expressed microRNAs target several genes involved in pancreas organogenesis.
Keywords: Diabetes; Insulin-producing cells; iPSC; microRNAs.