The research also suggests that some of these miRNAs, when acting abnormally, may contribute to certain forms of leukemia.
“Basically, we found that a specific set of miRNA genes are turned off in normal platelet development, but turned on in certain platelet-related leukemia cells,” said lead author Dr Ramiro Garzon, a clinical instructor in The Ohio State University College of Medicine.
MiRNA helps to regulate many key biological processes, including cell growth, death, development and differentiation. The study is published online in the Proceedings of the National Academy of Sciences.
The researchers had previously uncovered substantial evidence linking certain patterns of miRNA to both normal and abnormal blood cell development, especially in diseases like chronic lymphocytic leukemia and lymphoma. Relatively little was known, however, about miRNA functionality in platelet formation.
Platelets are created from stem cells in the bone marrow. They evolve through a process called megakaryocytopoiesis, which generates megakaryocytes, or platelet parent cells.
The research team used microRNA gene chip analysis to identify miRNA expression in normal stem cells and megakaryoctyes. They also studied miRNA expression patterns in four acute megakaryoblastic leukemia (AMKL) cell lines. They discovered that a set of 17 miRNAs are turned off during normal megakaryocyte differentiation and that eight of those genes create a molecular signature that clearly defines a megakaryocyte from any other type of cell.
“We believe this set of genes may contribute to platelet formation,” says Garzon. “We think that when these miRNAs are turned off, it’s a signal to other gene targets to get busy with the normal process of development.” Garzon says just the opposite happens in AMKL, an unusual form of leukemia more often found in children than adults.
Researchers believe that more knowledge about miRNA could lead to a new class of targeted therapies that may be helpful in treating leukemia and other diseases. However, much more research is needed before this goal can be realized.