Genetically engineered heart cells can be stimulated using light, reports a study online this week in Nature Methods. These cells allow the heart to be stimulated in ways that will be helpful to explore normal heart function and opens the possibility of using light as a pacemaker in research studies involving rodents.
This well established approach, referred to as optogenetics, uses genetically encoded photosensitive proteins from microorganisms to control cell behavior with light. The cation channel Channelrhodopsin-2 (ChR2) is opened by pulses of blue light and triggers the transmission of electrical signals when expressed on the surface of excitable cells. Neuronal cells overexpressing ChR2 are common tools in neurobiology because they can be selectively activated. Philipp Sasse and colleagues have extended the use of ChR2 to another type of excitable cell in the body, namely heart cells.
The researchers expressed ChR2 in mouse cardiomyocytes and used light to precisely stimulate the cells growing in a dish and in the heart of transgenic mice. Light pulses provoked localized and prolonged electrical currents in heart cells.