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SAN FRANCISCO — A protein borrowed from Dead Sea microbes and re-engineered by researchers makes heart cells light up with every contraction. The flashing cells may offer a way to predict whether new drugs will cause heart problems in people, Harvard researchers reported December 17 at the American Society for Cell Biology annual meeting.
Adam Cohen and his colleagues took a protein that helps a Dead Sea microorganism harvest energy from sunlight and broke the molecule so it works only in reverse, giving off instead of absorbing light under certain conditions. When placed in heart cells, the protein — called archaerhodopsin 3, or Arch for short — flashes dim red light when heart cells get an electrical signal to beat, Cohen reported. A different version of the Arch protein blinks blue when calcium enters the cell or is released from storage depots inside the cell to trigger heart muscle contractions. (Click here to view a movie of the protein in action.)
The idea for the flashing cells came from a new field of research known as optogenetics, in which researchers use flashes of light to control the activity of nerve cells. The new technique doesn’t alter the way the heart cells function; it simply allows Cohen and his colleagues to monitor the beating of human heart cells.
The researchers placed the red and blue twinkling proteins into human skin cells that had been reprogrammed to make stem cells and then were coaxed into becoming heart muscle cells. Even growing in a laboratory dish, the cells beat in time with each other. In the future, reprogrammed cells could be created from skin cells taken from people with genetic heart problems to learn more about how their condition affects heart cell function.