Mystery of ExRNA

So the government undertakes a multimillion dollar program to investigate mysterious messengers from an uncharted world. Sound like the X-files? Actually it’s NIH, the National Institutes of Health. And the mystery messengers are within our own body, tiny particles called exRNA or extracellular RNA. Molecules of RNA that are made within a cell, copied from DNA the same way as the messenger RNAs that specify proteins–but unlike normal messenger RNAs, exRNAs actually leave the cell, typically protected in little bubbles of fat. So where do exRNAs end up–and what are they doing?

Like UFOs, exRNAs have been reported since the early twentieth century, but rarely taken seriously. Now, just within the past decade, their implications have exploded. exRNAs are found in all kinds of boy fluids, such as blood, saliva, semen, and vaginal fluids. In other words, they can travel throughout the body–and may end up inside other people’s bodies.

The obvious implication is cell-to-cell communication. Cells tell other cells what to do, throughout development and healthy function of our bodies. But abnormal messages can direct our cells to do abnormal things, like start a cancer. Cancers have already been associated with specific exRNA sequences; for instance pancreatic cancer is associated with elevation of a specific external RNA called miR-210, also known as a microRNA. The miR-210 microRNA is already known as a life-or-death regulator molecule within cells, associated with recovery from heart attacks but also with tumors. Even if exRNAs turn out not to serve therapy, they have enormous potential as markers of early-stage cancers, allowing diagnosis in time to treat. exRNA represents the kind of ground-breaking research for which we depend on NIH–your tax dollars at work.