Enter a research team led by Deepak Srivastava, M.D, director of GICD, world leaders in the characterization of microRNAs (miRNAs). These small, single-stranded molecules of ribonucleic acid (RNA), discovered in the Victor Ambros lab in 1993, fine-tune protein levels in all cells of the body. The GICD team discovered that miRNAs control VSMC differentiation and growth.
Gene expression is the process where information encoded in genes is converted into proteins, the workhorse molecules that make up the body's structures and carry its signals. While genes are encoded in chains of deoxyribonucleic acids (DNA), they are copied into chains of messenger ribonucleic acids (mRNA) that are "read" by cellular machines that build proteins. microRNAs bind to messenger RNAs, usually targeting them for breakdown or rendering them unfit to serve as templates for protein production.
The current study found that two miRNAs in particular, miR-143 and miR-145, are part of a molecular switch that determines whether VSMC persist as high-growth precursors or mature into functioning muscle cells. miR-143 was found to block the expression of factors that promote proliferation by VSMC precursors. Surprisingly, miR-145 activated the expression of myocardin, which maintains VSMC in their mature form over their high-growth form.
In a mouse model, expression of miR-143 and miR-145 was reduced to almost nothing where disease-related prol
|Contact: Greg Williams|
University of Rochester Medical Center