| Two distinguishing characteristics of stem cells, their continuous division in the undifferentiated state
and growth into any cell types, are orchestrated by a number of cell signaling pathways. These pathways
act as a niche factor in controlling variety of stem cells. The core stem cell signaling pathways include
Wingless-type (Wnt), Hedgehog (HH), and Notch. Additionally, they critically regulate the self-renewal
and survival of cancer stem cells. Conversely, stem cells’ main properties, lineage commitment and
stemness, are tightly controlled by epigenetic mechanisms such as DNA methylation, histone
modifications and non-coding RNA-mediated regulatory events. MicroRNAs (miRNAs) are cellular
switches that modulate stem cells outcomes in response to diverse extracellular signals. Numerous
scientific evidences implicating miRNAs in major signal transduction pathways highlight new crosstalks
of cellular processes. Aberrant signaling pathways and miRNAs levels result in developmental defects and
diverse human pathologies. This review discusses the crosstalk between the components of main
signaling networks and the miRNA machinery, which plays a role in the context of stem cells
development and provides a set of examples to illustrate the extensive relevance of potential novel
therapeutic targets. |