Published in the current online edition of the Proceedings of the National Academy of Sciences, the study evaluates the role of short RNAs, also known as miRNAs, in the early stages of the developing heart. The study also will be reported in the December 27 issue of PNAS.

The findings could help cardiac stem cell researchers one day develop strategies for gene and cell- mediated cardiac therapies, according to Deepak Srivastava, MD, senior author and GICD director.

RNAs are nucleic acids found in all living cells that help transfer information from DNA to the protein-forming system of the cell. They also express--that is, instruct to turn on or off--genes within that transferred information. MiRNAs are short RNAs that repress gene expression to control a variety of developmental processes.

"Of all the medical disciplines that could potentially benefit from stem cell research, cardiology is among the most promising, but a better understanding of early heart development is crucial in order to move forward to stem cell-mediated therapies," says Srivastava, who holds appointments as professor in the Department of Pediatrics and the Wilma and Adeline Pirag Distinguished Professor in Pediatric Developmental Cardiology at UCSF.

In the study, which used Drosophila fly embryos as model systems, the research team demonstrated that a form of miRNA known as miR-1 helps in determination of heart progenitor cells (stem cells) in early embryonic stages. They also showed that miR-1 helps in maintenance of heart precursors in later embryonic stages.

In addition, researchers demonstrated that miR-1 can repress the ligand Delta, which otherwise binds to its receptor, Notch. The binding of Delta and Notch mediates development of many kind
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Contact: John Watson
jwatson@gladstone.ucsf.edu
415-734-2019
Gladstone Institutes
16-Dec-2005