| Title | Modulation of Cardiac Tissue Electrophysiological Properties with Light-Sensitive Proteins |
| Author | Udi Nussinovitch, Rami Shinnawi and Lior Gepstein |
| Affiliation(s) | Correspondence: Lior Gepstein, MD, PhD. Rappaport Faculty of Medicine and Research Institute, Technion – Israel Institute of Technology. POB 9649, Haifa 31096, Israel. Tel.: +972-4-8295303; fax: +972-4-8524758. E-mail: mdlior@tx.technion.ac.il. |
| Published |
Cardiovasc Res (2014) doi: 10.1093/cvr/cvu037
First published online: February 11, 2014 |
| Keyword | 624nm Optogenetics pacing cell and gene therapies cardiac resynchronization therapy conduction block |
| Snippet | ... entire culture was used. For activation of ArchT, a high-output 624nm LED illumination system
was used (Prizmatix, Israel), which was coupled with a 2mm optical fiber. Continuous (30sec)
illuminations were carried out during the MEA recordings. Statistical Analysis ... |
| Abstract | A combined cell and gene therapy strategy was developed in which fibroblasts were transfected to express the light-activated depolarizing channel Channelrhodopsin-2 (ChR2). Patch-clamp studies confirmed the development of a robust inward current in the engineered fibroblasts following monochromatic blue-light exposure. The engineered cells were co-cultured with neonatal rat cardiomyocytes (or human embryonic stem cell-derived cardiomyocytes) and studied using a multielectrode array mapping technique. These studies revealed the ability of the ChR2-fibroblasts to electrically couple and pace the cardiomyocyte cultures at varying frequencies in response to blue-light flashes. Activation mapping pinpointed the source of this electrical activity to the engineered cells. Similarly, diffuse seeding of the ChR2-fibroblasts allowed multisite optogenetics pacing of the co-cultures, significantly shortening their electrical activation time and synchronizing contraction. Next, optogenetics pacing in an in-vitro model of conduction block allowed the resynchronization of the tissue's electrical activity. Finally, the ChR2-fibroblasts were transfected to also express the light-sensitive hyperpolarizing proton-pump Archaerhodopsin-T (Arch-T). Seeding of the ChR2/ArchT-fibroblasts allowed to either optogentically pace the cultures (in response to blue-light flashes) or to completely suppress the cultures' electrical activity (following continuous illumination with 624 nm monochromatic-light, activating ArchT). |
