title: Optogenetics for suppression of cardiac electrical activity in human and rat cardiomyocyte cultures.
abstract: Optogenetics has revolutionized neuroscience by enabling precise control of neural excitation. The development of similar optogenetics strategies in the heart is just emerging and mainly focused on pacing with light activation of channelrhodopsin-2. Here, we aimed to develop an optogenetic approach to suppress local cardiac electrical activity by using engineered cell-grafts (HEK293-cells) transfected to express the light-sensitive hyperpolarizing proton-pump archaerhodopsin-3 (Arch3). To evaluate the ability of the engineered cells to couple and modulate the electrical activity of cardiomyocytes, we co-cultured the Arch3-HEK293 cells with neonatal rat cardiomyocytes (NRCMs) or human embryonic stem cells derived cardiomyocytes (hESC-CMs). The co-cultures' conduction and chronotropic properties were evaluated prior, during, and following application of focused monochromatic light (590 nm) using a multielectrode array mapping system. Application of focused illumination completely silenced electrical activity at the illuminated area in all NRCM co-cultures, leading to development of localized functional conduction blocks. Similarly, illumination significantly slowed spontaneous beating-rate in the hESCs-CMs co-cultures (from [Formula: see text] to [Formula: see text], [Formula: see text]). Interestingly, a transient acceleration in beating-rate was noted immediately postillumination. In conclusion, a combined gene and cell therapy approach, using light-sensitive hyperpolarizing proteins, could be used to modulate conduction and automaticity in cardiomyocyte cultures, opening the way for future optogenetic treatments for cardiac tachyarrhythmias.
authors.affiliation: Technion-Israel Institute of Technology , Sohnis Family Laboratory for Cardiac Electrophysiology and Regenerative Medicine, Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa, POB 9649, Haifa 31093, Israel ; Rambam Health Care Campus , Department of Internal Medicine A, Haifa 31096, Israel.
authors.forename: Udi
authors.initials: U
authors.lastname: Nussinovitch
authors.affiliation: Technion-Israel Institute of Technology , Sohnis Family Laboratory for Cardiac Electrophysiology and Regenerative Medicine, Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa, POB 9649, Haifa 31093, Israel ; Rambam Health Care Campus , Cardiology Department, Haifa 31096, Israel.
authors.forename: Lior
authors.initials: L
authors.lastname: Gepstein
keywords: archaerhodopsin; cardiac suppression; cardiomyocytes; molecular ablation; optogenetics