Mgh LogoMicroRNAs (miRNAs) short strands of RNA are believed to bind and silence the expression of their target genes. They seem to be vital in cellular development and differentiation. Scientists from the Massachusetts General Hospital (MGH) and the Harvard Stem Cell Institute have supposedly found a novel mechanism regulating the number of hematopoietic stem cells. This newly discovered minute RNA molecule is affirmed to elevate the number of these blood stem cells and may help enhance cancer treatment.

These RNA strands are possibly not included in the production of proteins. But are comprised in the process wherein hematopoietic stem cells (HSCs) mature into red or white blood cells. It was ascertained that these stem cells give rise to all blood and immune system cells.

David Scadden, MD, director of the MGH Center for Regenerative Medicine and senior investigator of the report quoted, “This novel molecule raises blood stem cell numbers by suppressing the normal cell-death process. We’ve known that these non-coding RNAs can define what an immature cell will become, but none has previously been identified that can tell a blood system stem cell whether to live or die.”

It is claimed that the process controlling the size of the HSC population was a mystery, hence scientists aimed to ascertain if miRNAs are involved in this process. The experts explain that when the enzyme Dicer is missing HSCs are unable to survive. Moreover, Dicer is believed to create microRNAs, so it can be affirmed that microRNAs manage the level of HSC.

Scadden the Gerald and Darlene Jordan Professor of Medicine at Harvard Medical School and co-director of the Harvard Stem Cell Institute explained, “These molecules modify cellular numbers in ways that can be both beneficial and detrimental, so it will be important to understand the differences. We’re now looking at ways to expand the stem cell population – to briefly turn on the anti-cell-death protection – to overcome limited levels of stem cells that can restrict the use of stem cell transplantation for patients with blood system failure and blood-cell cancers. Accomplishing that could make life-saving stem cell transplants available to more patients.”

The experts also ascertained the presence of a microRNA group at elevated levels in HSCs. It was revealed that one of them called as miRNA-125a heightens the number of HSCs. This miRNA does this by possibly safeguarding HSC from the cell-death process that generally confines cellular populations. The guarding effects of miRNA-125a were probably monitored at the stem-cell level alone. The RNA strand is assumed to protect HSC by curbing the cell-death protein Bak1.

The research is published online in the early edition of Proceeding of the National Academy of Sciences.