Using a bistable animal opsin for switchable and scalable optogenetic inhibition of neurons

• Published in: EMBO reports 2021-05, Vol.22 (5), p.e51866-n/a
• Main Authors: Rodgers, Jessica, Bano-Otalora, Beatriz, Belle, Mino D C, Paul, Sarika, Hughes, Rebecca, Wright, Phillip, McDowell, Richard, Milosavljevic, Nina, Orlowska-Feuer, Patrycja, Martial, Franck P, Wynne, Jonathan, Ballister, Edward R, Storchi, Riccardo, Allen, Annette E, Brown, Timothy, Lucas, Robert J
• Format: Article
• Language: English
• Subjects: Animals; Bipolar cells; bistable; Degeneration; EMBO22; EMBO27; GPCR; Hypothalamus; Luminous intensity; Mice; Neurodegeneration; neuronal inhibition; Neurons; Opsins; Opsins - genetics; Optogenetics; Retina; Retinal cells; Retinal degeneration; Rod Opsins - genetics; Signaling; Spectral composition; Suprachiasmatic nucleus; Wavelength; Wavelengths
• ISSN: 1469-221X; 1469-3178; 1469-3178
• DOI: 10.15252/embr.202051866

There is no consensus on the best inhibitory optogenetic tool. Since Gi/o signalling is a native mechanism of neuronal inhibition, we asked whether Lamprey Parapinopsin (“Lamplight”), a Gi/o-coupled bistable animal opsin, could be used for optogenetic silencing. We show that short (405 nm) and long (525 nm) wavelength pulses repeatedly switch Lamplight between stable signalling active and inactive states, respectively, and that combining these wavelengths can be used to achieve intermediate levels of activity. These properties can be applied to produce switchable neuronal hyperpolarisation and suppression of spontaneous spike firing in the mouse hypothalamic suprachiasmatic nucleus. Expressing Lamplight in (predominantly) ON bipolar cells can photosensitise retinas following advanced photoreceptor degeneration, with 405 and 525 nm stimuli producing responses of opposite sign in the output neurons of the retina. We conclude that bistable animal opsins can co-opt endogenous signalling mechanisms to allow optogenetic inhibition that is scalable, sustained and reversible. SYNOPSIS Lamprey parapinopsin is a Gi/o-coupled bistable animal opsin activated and deactivated by short and long wavelength light, respectively. This study shows that Lamplight can be used as a reversible inhibitory optogenetic tool in mice. Lamplight can produce reversible hyperpolarisation in brain neurons and photoswitchable changes in the retina. Single light pulses can produce sustained inhibition. Lamplight-driven Go activity can be controlled by modulating either the intensity or the spectral composition of the light stimulus. Graphical Abstract Lamprey parapinopsin is a Gi/o-coupled bistable animal opsin activated and deactivated by short and long wavelength light, respectively. This study shows that Lamplight can be used as a reversible inhibitory optogenetic tool in mice.