Human mast cells and mastocytosis: harnessing microRNA expression as a new approach to therapy?

MicroRNAs (miRNAs) are short, non-coding RNAs that have emerged as key post-transcriptional regulators in a wide variety of organisms and critical cellular processes. Because any one miRNA can regulate the expression of a distinct set of genes, differential miRNA expression can shape the repertoire of proteins that are actually expressed during development, differentiation, or disease. To understand what goes wrong when a cell becomes transformed requires knowledge of the processes that ensure normal development. It is now clear that miRNAs may act as oncogenes and/or tumor suppressors within gene regulatory networks, thereby contributing to the development of cancer. Mast cells are long-lived cells, widely distributed throughout vascularized tissues, in particular near surfaces that are exposed to the environment (such as skin, airways, and the gastrointestinal tract), where they contribute to bacterial clearance, enhancement of adaptive immune responses, modulation of inflammation, and the degradation of toxic peptides and venoms. Here we review current knowledge in the field of mast-cell differentiation and disease in humans and mice and discuss future directions and links between mast-cell differentiation, oncogenic transformation, and microRNAs as well as possible new points of entry for therapeutic intervention.