title: Optogenetic pacing in Drosophila melanogaster.
abstract: Electrical stimulation is currently the gold standard for cardiac pacing. However, it is invasive and nonspecific for cardiac tissues. We recently developed a noninvasive cardiac pacing technique using optogenetic tools, which are widely used in neuroscience. Optogenetic pacing of the heart provides high spatial and temporal precisions, is specific for cardiac tissues, avoids artifacts associated with electrical stimulation, and therefore promises to be a powerful tool in basic cardiac research. We demonstrated optogenetic control of heart rhythm in a well-established model organism, Drosophila melanogaster. We developed transgenic flies expressing a light-gated cation channel, channelrhodopsin-2 (ChR2), specifically in their hearts and demonstrated successful optogenetic pacing of ChR2-expressing Drosophila at different developmental stages, including the larva, pupa, and adult stages. A high-speed and ultrahigh-resolution optical coherence microscopy imaging system that is capable of providing images at a rate of 130 frames/s with axial and transverse resolutions of 1.5 and 3.9 μm, respectively, was used to noninvasively monitor Drosophila cardiac function and its response to pacing stimulation. The development of a noninvasive integrated optical pacing and imaging system provides a novel platform for performing research studies in developmental cardiology.
authors.affiliation: Department of Electrical and Computer Engineering, Lehigh University, Bethlehem, PA 18015, USA. ; Center for Photonics and Nanoelectronics, Lehigh University, Bethlehem, PA 18015, USA.
authors.forename: Aneesh
authors.initials: A
authors.lastname: Alex
authors.affiliation: Genetics and Aging Research Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02129, USA.
authors.forename: Airong
authors.initials: A
authors.lastname: Li
authors.affiliation: Genetics and Aging Research Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02129, USA.
authors.forename: Rudolph E
authors.initials: RE
authors.lastname: Tanzi
authors.affiliation: Department of Electrical and Computer Engineering, Lehigh University, Bethlehem, PA 18015, USA. ; Center for Photonics and Nanoelectronics, Lehigh University, Bethlehem, PA 18015, USA. ; Bioengineering Program, Lehigh University, Bethlehem, PA 18015, USA.
authors.forename: Chao
authors.initials: C
authors.lastname: Zhou
keywords: Drosophila; Heart development; Label-free imaging; Optical coherence microscopy; Optical coherence tomography; Optogenetics