Gene expression in mammals is controlled not only by proteins but by small noncoding RNAs called microRNAs. The involvement of these RNAs provides powerful clues about the molecular origins of human diseases and how they might be treated. Ischemic diseases arise from an inadequate blood supply. Bonauer et al. find that a specific microRNA that is expressed in the cells lining blood vessels (called miR-92a) functions to repress the growth of new blood vessels. MiR-92a probably acts through effects on expression of integrins, proteins involved in cell adhesion and migration. In mouse models in which an inadequate blood supply had caused damage either to heart or limb muscle, therapeutic inhibition of miR-92a led to an increase in blood vessel density in the damaged tissues and enhanced functional recovery.
A. Bonauer, G. Carmona, M. Iwasaki, M. Mione, M. Koyanagi, A. Fischer, J. Burchfield, H. Fox, C. Doebele, K. Ohtani, E. Chavakis, M. Potente, M. Tjwa, C. Urbich, A. M. Zeiher, S. Dimmeler, MicroRNA-92a controls angiogenesis and functional recovery of ischemic tissues in mice. Science 324, 1710–1713 (2009). [Abstract] [Full Text]