Heard of the Microbiome? Meet the MicroRNAome.

Oct. 31, 2017

Graphic representation of a cell's nucleus with DNA and RNAA University of Rochester Medical Center researcher is part of a team that is working toward characterizing where a certain type of RNA, called microRNA, is expressed in human cells. In a recent study, published in Genome Research, the team made a giant set of data about these RNA available to the public to guide research and foster the development of new therapies.

RNA, the close cousin of DNA, comes in many flavors - each with a specific role. MicroRNA (miRNA) help regulate which proteins are produced in a cell and how much. Fiddling with the level of proteins can have subtle or large impacts on that cell’s activity and can even cause disease. 

Several studies have linked miRNAs to diseases, either as the cause or simply a marker. While some of these links could lead to new treatments, others may just be red herrings.  

“We've showed previously that when somebody claims a certain miRNA is a marker of a disease, at times it's just a marker of increased inflammation, which is a side effect of a lot of diseases,” said Matthew N. McCall, Ph.D., assistant professor of Biostatistics and Biomedical Genetics at URMC and an author on the study.

According to McCall and study leader Marc K. Halushka, M.D., Ph.D., associate professor of Pathology and director of Oncology Tissue Services at Johns Hopkins University School of Medicine, before you can understand what miRNAs are doing, you need to know where they are.

And why is that important?

Within a given tissue in your body, there could be thousands of different cells types, serving different purposes. When measuring RNA in a tissue biopsy, you will get a mixture of RNA from all of these different cell types, whether or not they are relevant to the disease you are interested in.

For their study, Halushka’s team pulled together all that was known about miRNA in human cells and conducted experiments to fill the gaps. Though it wasn’t their specific intent, the researchers found that many miRNAs originally thought to be expressed in all or many cell types actually are not. Rather, they are expressed in cells that get into all or most tissues, like blood or inflammatory cells, and could be mistakenly associated with a disease.

All of the data from Halushka’s study are available in an online database and in the University of California, Santa Cruz Genome Browser and will be updated regularly. Having access to this data should save researchers a lot of time and help weed out some those aforementioned red herrings. With just a few clicks, researchers can find all of the cells types that express a specific miRNA or all of the miRNAs expressed in a specific cell type.

To learn more, read the full study in Genome Research.