Non-invasive red-light optogenetic control of Drosophila cardiac function

Men et al. develop an optogenetic pacing tool to controlDrosophilaheart rhythm noninvasively with red light. Using optical coherence microscopy imaging, they demonstrate effective light-induced tachypacing, bradypacing, and restorable cardiac arrest in transgenic fly models. This study provides a user-friendly research platform for noninvasive cardiac optogenetic studies. Drosophilais a powerful genetic model system for cardiovascular studies. Recently, optogenetic pacing tools have been developed to controlDrosophilaheart rhythm noninvasively with blue light, which has a limited penetration depth. Here we developed both a red-light sensitive opsin expressingDrosophilasystem and an integrated red-light stimulation and optical coherence microscopy (OCM) imaging system. We demonstrated noninvasive control ofDrosophilacardiac rhythms using a single light source, including simulated tachycardia in ReaChR-expressing flies and bradycardia and cardiac arrest in halorhodopsin (NpHR)-expressing flies at multiple developmental stages. By using red excitation light, we were able to pace flies at higher efficiency and with lower power than with equivalent blue light excitation systems. The recovery dynamics after red-light stimulation of NpHR flies were observed and quantified. The combination of red-light stimulation, OCM imaging, and transgenicDrosophilasystems provides a promising and easily manipulated research platform for noninvasive cardiac optogenetic studies.