microRNA regulation in megakaryocytopoiesis.

Megakaryocytopoiesis is governed by a complex network of haematopoietic growth factors that regulate the different stages of the process, in which haematopoietic stem cells undergo megakaryocytic lineage commitment, proliferation, maturation, and functional activation to produce platelets. MicroRNAs (miRNA) are a class of about 22-nucleotide noncoding RNAs that have been highly conserved during evolution and play a significant role in haematopoiesis, including differentiation and lineage commitment of megakaryocyte. This review summarizes the miRNAs which have changed expression during megakaryocytopoiesis, and their positive and negative functions on megakaryocytic differentiation. In addition, the abnormal miRNA expression profiles in megakaryocytic disorders are reviewed. 2011 Blackwell Publishing Ltd.