Biology subjects

Hagio, H.

Publications and source records attributed to Hagio, H..

3 recordsLinked to original sources

bioRxiv2022

Optogenetic manipulation of second messengers in neurons and cardiomyocytes with microbial rhodopsins and adenylyl cyclase

Even though microbial photosensitive proteins have been used for optogenetics, their use should be optimized to precisely control second messengers in vivo. We exploited GtCCR4 and KnChR, cation channelrhodopsins from algae, BeGC1, a guanylyl cyclase rhodopsin from a fungus, and photoactivated adenylyl cyclases (PACs) from cyanobacteria (OPAC) or bacteria (bPAC), to control cell functions in zebrafish. Optical activation of GtCCR4 and KnChR in the hindbrain reticulospinal V2a neurons, which are involved in locomotion, immediately induced swimming behavior, whereas activation of BeGC1 or PACs was achieved at a short latency. KnChR had the highest locomotioninducing activity of all the channelrhodopsins examined. Activation of GtCCR4 and KnChR in cardiomyocytes induced cardiac arrest, whereas activation of bPAC gradually induced bradycardia. KnChR activation led to an increase in intracellular Ca2+ in the heart, suggesting that depolarization caused cardiac arrest. These data suggest that these optogenetic tools can be used to reveal the roles of second messengers in various cell types in vertebrates. Impact statementWe identified efficient and useful microbial channelrhodopsin, guanylyl cyclase rhodopsin, and photoactivated adenylyl cyclase that regulate neural activity and cardiac function in zebrafish. Major subject areasNeuroscience, Cell biology Research organismZebrafish (Danio rerio)

neuroscience↗

bioRxiv2022

Optogenetic manipulation of Gq-and Gi/o-coupled receptor signaling in neurons and heart muscle cells

G protein-coupled receptors (GPCRs) transmit extracellular signals into the cell depending on the type of G protein. To analyze the functions of GPCR signaling, we developed optogenetic tools using animal G protein-coupled bistable rhodopsins that can be controlled into active and inactive states by light irradiation. We expressed Gq- and Gi/o-coupled bistable rhodopsins in hindbrain reticulospinal V2a neurons, which are involved in locomotion, or in cardiomyocytes of zebrafish. Light stimulation of the reticulospinal V2a neurons expressing Gq-coupled spider Rh1 resulted in an increase in the level of cytoplasmic Ca2+ and evoked swimming behavior. Light stimulation of cardiomyocytes expressing the Gi/o-coupled mosquito Opn3, pufferfish TMT opsin, or lamprey parapinopsin induced cardiac arrest, and the effect was suppressed by treatment with pertussis toxin or barium, suggesting that Gi/o-dependent regulation of inward-rectifier K+ channels controls cardiac function. These data indicate that these rhodopsins are useful for optogenetic control of GPCR-mediated signaling in neurons and cardiomyocytes in vivo. Impact statementAnimal G protein-coupled bistable rhodopsins can regulate Gq and Gi-mediated signaling in a light-dependent manner in neurons and cardiomyocytes, making them useful for analyzing roles of GPCR signaling in vivo.

neuroscience↗

bioRxiv2020

Non-thalamic origin of zebrafish sensory relay nucleus: convergent evolution of visual pathways in amniotes and teleosts

Ascending visual projections similar to the mammalian thalamocortical pathway are found in a wide range of vertebrate species, but their homologous relationship is debated. To get better insights into their evolutionary origin, we examined the developmental origin of a visual relay nucleus in zebrafish (a teleost fish). Similarly to the tectofugal visual thalamic nuclei in amniotes, the lateral part of the preglomerular complex (PG) in teleosts receives tectal information and projects to the pallium. However, our cell lineage study reveals that the majority of PG cells are derived from the midbrain, not from the forebrain. We also demonstrate that the PG projection neurons develop gradually until juvenile stage, unlike the thalamic projection neurons. Our data suggest that teleost PG is not homologous to the amniote thalamus and that thalamocortical-like projections can evolve from a non-forebrain cell population. Thus, sensory pathways in vertebrate brains exhibit a surprising degree of variation.

neuroscience↗