tency, including the ability to differentiate into multiple cell types, germline transmission, teratoma formation, and contribution to chimeras. The iPSCs can be reprogrammed from various sources, and embryonic fibroblasts in mice and skin fibroblasts in humans are the preferable sources. Somatic cells can be reprogrammed through various methods, using retroviruses, lentiviruses, adenoviruses, and small RNAs. Differences in the choice of somatic cells source and reprogramming method cause variation among iPSCs and ultimately have a huge impact on safety pertaining to cell therapy. Prior to that, many studies examined genome-wide patterns of iPSCs and ESCs in complex regulatory networks linking chromatin structure and gene expression programs, as well as mRNA and microRNA expression profiles, to improve understanding of genomic and epigenomic networks underlying reprogramming, self-renewal, and cell fate decisions. One regulatory factor that has received increasing attention is miRNAs, which have the ability to regulate many target genes and control gene expression through translational repression and 1 Profiling of miRNA in Human and Mouse ES/iPS Cells degradation. miRNAs are expressed at different levels in a wide range of cells, including ESCs, iPSCs, and somatic cells. Recent work showed that introduction of miR302/367 resulted in higher reprogramming efficiency compared to exogenous OSKM transcription factors, indicating the importance of miRNAs in modulating the transition of somatic cells to pluripotent cells. In addition, miRNAs have been identified 11881984 as important regulators of cell growth and differentiation and have also been used in the identification or classification of specific cell types. In ES and iPS cells, several stem cell-specific miRNAs were identified and shown to be highly related to each other as they are grouped in a 7685384 cluster on the same chromosome and are transcribed as a single primary transcript. The miRNAs, reported in numerous studies and expressed abundantly in human and mouse pluripotent cells, are members of the miR-302 cluster. Other previously identified miRNAs are a chromosome 19 microRNA cluster including miR-517a, miR-519b, miR-520b, miR-520b, and miR-521, which were found to be highly expressed in human stem cells; the miR290 cluster was only detected at high levels in mouse stem cells. Several technologies are available for miRNA profiling, and each of them may be better than others in terms of sensitivity, cost efficiency, sequence dependence, or avoidance of MedChemExpress Roscovitine potential contamination from artifacts. The selection of techniques with different approaches and experimental settings may explain fundamental differences observed, especially when a variety of pluripotent and differentiated cell lines from different species are used. Thus, in our work, we take advantage of a 
miRNA array system that offers consistent settings to be applied to different types of cells in both humans and mice. Currently, no study has focused on miRNA expression profiling in human and mouse ES and iPS cells at the same time. In this study, we comprehensively analyzed miRNA expression patterns in both human and mouse cells. Inhibitory Factor, and 0.2% -mercaptoethanol. The cells were cultured on 0.1% gelatin-coated plates with monolayer of mitomycin-C treated mouse embryonic fibroblast. Mouse ESCs were cultured in the same culture conditions as iPSCs while ES_CCE, which was donated by Dr. Shin-ichi Nishikawa, was cultured in the sa