microRNA expression profiles in two‐ and three‐dimensional culture conditions of human‐umbilical‐cord blood‐derived CD34 + cells

: Human umbilical cord blood (HUCB) is a suitable source of hematopoietic stem cells (HSCs) for therapeutic transplantation. Different approaches have been used to expand the number of HSCs to increase the rate of HSC transplantation success in patients, such as using different cocktails of cytokines, feeder cell layers, and biocompatible scaffolds. microRNAs (miRNAs) are small noncoding RNAs that regulate gene expression posttranscriptionally. They play crucial roles in hematopoiesis including stem cell proliferation, differentiation, stemness, and self-renewal properties. Here, we studied the UCB-derived CD34+ cell expansion and the miRNA signatures of CD34+ cells on two- and three-dimensional (2D and 3D) culture conditions. We successfully expanded the UCB-derived CD34+ cells in both liquid culture (2D) and on aminated polyethersulfone nanofiber scaffolds (3D). Next, we identified the miRNA signature of CD34+ cells and their target genes. We found 58 dysregulated miRNAs in 3D culture condition and 34 dysregulated miRNAs in 2D culture condition when compared to the freshly isolated CD34+ cells. Various types of target genes were also predicted in both conditions using two online databases.