Scientists at the University of California, San Francisco, have discovered a molecular cocktail that enables fibroblasts to transform directly into cardiac muscle cells without first reverting to a stem cell state (Ieda M et al. Cell. 2010;142:375-386).
Starting with 14 gene regulators or transcription factors that are known to play a role in heart development, the researchers found that 3 of them—transcription factors Gata4, Mef2c, and Tbx5—are essential for generating cardiomyocytes. Heart or skin fibroblasts that acquired (via a viral vector) the genes encoding these 3 factors were reprogrammed within 3 days and, after several weeks, turned into heart muscle cells. Fibroblasts transplanted into mouse hearts 1 day after expression of the transcription factors also differentiated into cells that contracted spontaneously and expressed cardiac-specific markers and cardiomyocyte-specific genes.
Hampton T. Reprogramming Cells. JAMA. 2010;304(13):1432. doi:10.1001/jama.2010.1367