961C Poster - 15. Models of human disease
Saturday April 09, 1:30 PM - 3:30 PM

Authors:
Fei Wang; Elena Gracheva; Abby Matt; Hongwu Liang; Matthew Fishman; Chao Zhou

Affiliation: Washington University in St. Louis, Saint Louis, MO

Keywords:
j. cardiovascular disease; b. live imaging

Cardiac optogenetics is a promising alternative to traditional electrical stimulations in controlling the activity of cardiac tissues non-invasively. In recent years, cardiac functions of animals such as rats, zebrafish, and fruit fly, have been controlled by opsin activation. In this study, we expressed red-shifted excitatory opsins (ReaChR and ChRmine) in the heart of Drosophila melanogaster. For ReaChR and ChRmine, we used red-light stimulation for deep penetration into the myocardial structures. Compared to existing opsins, the newly generated opsin ChRmine is able to induce spiking with much lower irradiance power. M-mode images acquired with custom optical coherence microscopy (OCM) system demonstrated controlled heart function in vivo and in real-time throughout the Drosophila life cycle (larva, early pupa, late pupa, and adult). Fast kinetics, low stimulation power, and broad heart-rate adjustable range were demonstrated for light pulses pacing. Drosophila heart rate can be enhanced to the frequency of the light excitation, faster than its resting heart rate, and reversible acceleration of heartbeats can be achieved at various developmental stages. This study demonstrated non-invasive cardiac control through promoting heart functions of an intact animal, which is promising for the nondestructive studies of cardiac diseases, such as congenital heart disease, posteriority bradycardia, tachycardia, and regional mechanical dys-synchrony.