Yale University scientists have found tiny snippets of RNA are crucial to the formation of blood vessels – a process called angiogenesis that is crucial to everything from early development to heart disease and the spread of cancer.

The findings, which could lead to new ways to diagnose diseases such as cancer, macular degeneration, and stroke, were reported online yesterday in the journal Proceedings of the National Academy of Sciences.
"The role of small RNAs in blood vessels is a new area of research. Our findings really point towards novel approaches to either choke off the blood supply to tumors or to promote the growth of blood vessels when needed," says William Sessa, professor of pharmacology and director of the vascular biology & therapeutics program at the Yale School of Medicine and senior author of the study.
Scientists for the past decade have learned about the ability of snippets of RNA, called microRNAs, or miRNAs, to regulate gene activity in a wide variety of biological functions.  Sessa and his colleagues showed that when they silenced miRNA production in mice they reduced angiogenic activity after birth. The reduction occurred even after the implantation of tumors or the introduction of vascular endothelial growth factor (or VEGF), both potent stimulators of blood vessel growth.
The functional role of miRNAs produced in endothelial cells, or blood vessel cells, had not been established before.
The work also suggests that miRNA might be represent a target for new cancer therapies. Many forms of cancer stimulate angiogenesis to create blood vessels that feed tumors.
"Recent work by our group and few others have shown that certain miRNAs are highly expressed in both tumors and endothelial cells lining the blood vessels of tumors suggesting that antagonism of key miRNAs may be a new therapeutic strategy for cancer," says Sessa.