Cell-to-cell shipping

It's no secret that we need new ways to treat and detect disease, including cancer. Specifically, we need better biomarkers that can be used for diagnosis and better ways to selectively get medicine where we want it to go in the body.

And while our DNA can tell us if we carry a gene for a particular disease, having the gene alone does not mean someone will develop a disease. This is because it is the RNA, the ribonucleic acid in our bodies, that expresses a gene and controls what the body makes with it.

In a paper published in The Journal of Extracellular Vesicles, University of Delaware RNA biologist Mona Batish and colleagues from UD, Johns Hopkins and Southern Medical University report that circular RNA highly expressed in extracellular vesicles known as exosomes found in our cells, might hold clues to unlocking cell communication in both health and disease.

Extracellular vesicles (EVs) are key molecules for cell-to-cell communication. Sometimes RNA is packaged in sophisticated EVs called exosomes that are assembled inside the cell, packed with all sorts of cellular material and then delivered to a recipient cell elsewhere in the body - the same way you might wrap Christmas presents and then add them to a FedEx delivery box that you can address, stamp and ship to another location.

Exosomes are selective in what they include and where they transport cargo in the body. Each exosome has a "key" of sorts decorated on the outside of the cell membrane. Once released in the body, exosomes go to their pre-programmed destination and wait for their key to "unlock" the membrane of the destination cell, so they can go inside and deliver material or change the cell's profile.

In the body, this could be a way to transfer disease, train neighboring cells to be alert for upcoming disease or even give code to silence detection of cancer nearby. It also might provide a biomarker for disease detection.

Batish, UD associate professor of medical and molecular sciences, and colleagues explored how a cell selects what to put into these exosomes, knowledge she said could prove useful in synthetic biology, specifically in RNA therapeutics, where researchers want to package and deliver RNA cargo to specific places in the body.

"If we understand how cells pick what goes inside, then we can engineer these exosomes outside the body using synthetic biology, package our target cargo (in this case RNA) inside, and it will be delivered efficiently and the body will accept it," said Batish. "From the other lens, we're trying to understand how this works so that we can better understand disease and identify biomarkers that can provide information about an individual's risk for disease or a way to provide early diagnosis."

Co-authors on the paper from UD include Batish, along with Ahmed Abdelgawad, Yanbao Yu and Vijay Parashar. Other co-authors from Johns Hopkins include Olesia Gololobova, Kenneth W. Witwer and Yiyao Huang, who is also affiliated with Southern Medical University.