Single-photon optogenetics enables precise, cell-type-specific modulation of neuronal circuits, making it a crucial tool in neuroscience. Its miniaturization in the form of fully implantable wide-field stimulator arrays enables long-term interrogation of cortical circuits and bears promise for brain-machine interfaces for sensory and motor function restoration. However, achieving selective activation of functional cortical representations poses a challenge, as studies show that targeted optogenetic stimulation results in activity spread beyond one functional domain. While recurrent network mechanisms contribute to activity spread, here we demonstrate with detailed simulations of isolated pyramidal neurons from cats of unknown sex that already neuron morphology causes a complex spread of optogenetic activity at the scale of one cortical column. Since the shape of a neuron impacts its optogenetic response, we find that a single stimulator at the cortical surface recruits a complex spatial distribution of neurons that can be inhomogeneous and vary with stimulation intensity and neuronal morphology across layers. We explore strategies to enhance stimulation precision, finding that optimizing stimulator optics may offer more significant improvements than the preferentially somatic expression of the opsin through genetic targeting. Our results indicate that, with the right optical setup, single-photon optogenetics can precisely activate isolated neurons at the scale of functional cortical domains spanning several hundred micrometers.

• Klíčová slova
• brain interface, morphology, neural stimulation, optogenetics, spatial precision, visual cortex,
• MeSH
• kočky MeSH
• modely neurologické MeSH
• mozková kůra fyziologie   cytologie   MeSH
• neurony fyziologie   MeSH
• optogenetika * metody   MeSH
• pyramidové buňky fyziologie   MeSH
• světelná stimulace metody   MeSH
• zvířata MeSH
• Check Tag
• kočky MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Schizophrenia research arose in the twentieth century and is currently rapidly developing, focusing on many parallel research pathways and evaluating various concepts of disease etiology. Today, we have relatively good knowledge about the generation of positive and negative symptoms in patients with schizophrenia. However, the neural basis and pathophysiology of schizophrenia, especially cognitive symptoms, are still poorly understood. Finding new methods to uncover the physiological basis of the mental inabilities related to schizophrenia is an urgent task for modern neuroscience because of the lack of specific therapies for cognitive deficits in the disease. Researchers have begun investigating functional crosstalk between NMDARs and GABAergic neurons associated with schizophrenia at different resolutions. In another direction, the gut microbiota is getting increasing interest from neuroscientists. Recent findings have highlighted the role of a gut-brain axis, with the gut microbiota playing a crucial role in several psychopathologies, including schizophrenia and autism.There have also been investigations into potential therapies aimed at normalizing altered microbiota signaling to the enteric nervous system (ENS) and the central nervous system (CNS). Probiotics diets and fecal microbiota transplantation (FMT) are currently the most common therapies. Interestingly, in rodent models of binge feeding, optogenetic applications have been shown to affect gut colony sensitivity, thus increasing colonic transit. Here, we review recent findings on the gut microbiota-schizophrenia relationship using in vivo optogenetics. Moreover, we evaluate if manipulating actors in either the brain or the gut might improve potential treatment research. Such research and techniques will increase our knowledge of how the gut microbiota can manipulate GABA production, and therefore accompany changes in CNS GABAergic activity.

• Klíčová slova
• Fecal microbiota transplantation, Gut microbiota, Gut optogenetics, NMDA hypoactivity, NMDARs/GABA interaction, Probiotic dietaries, Schizophrenia,
• MeSH
• lidé MeSH
• mozek MeSH
• optogenetika MeSH
• osa mozek-střevo MeSH
• probiotika * MeSH
• schizofrenie * terapie   MeSH
• střevní mikroflóra * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

T-tubules (TT) form a complex network of sarcolemmal membrane invaginations, essential for well-co-ordinated excitation-contraction coupling (ECC) and thus homogeneous mechanical activation of cardiomyocytes. ECC is initiated by rapid depolarization of the sarcolemmal membrane. Whether TT membrane depolarization is active (local generation of action potentials; AP) or passive (following depolarization of the outer cell surface sarcolemma; SS) has not been experimentally validated in cardiomyocytes. Based on the assessment of ion flux pathways needed for AP generation, we hypothesize that TT are excitable. We therefore explored TT excitability experimentally, using an all-optical approach to stimulate and record trans-membrane potential changes in TT that were structurally disconnected, and hence electrically insulated, from the SS membrane by transient osmotic shock. Our results establish that cardiomyocyte TT can generate AP. These AP show electrical features that differ substantially from those observed in SS, consistent with differences in the density of ion channels and transporters in the two different membrane domains. We propose that TT-generated AP represent a safety mechanism for TT AP propagation and ECC, which may be particularly relevant in pathophysiological settings where morpho-functional changes reduce the electrical connectivity between SS and TT membranes. KEY POINTS: Cardiomyocytes are characterized by a complex network of membrane invaginations (the T-tubular system) that propagate action potentials to the core of the cell, causing uniform excitation-contraction coupling across the cell. In the present study, we investigated whether the T-tubular system is able to generate action potentials autonomously, rather than following depolarization of the outer cell surface sarcolemma. For this purpose, we developed a fully optical platform to probe and manipulate the electrical dynamics of subcellular membrane domains. Our findings demonstrate that T-tubules are intrinsically excitable, revealing distinct characteristics of self-generated T-tubular action potentials. This active electrical capability would protect cells from voltage drops potentially occurring within the T-tubular network.

• Klíčová slova
• cardiac electrophysiology, excitation-contraction coupling, imaging,
• MeSH
• akční potenciály fyziologie   MeSH
• buněčná membrána MeSH
• kardiomyocyty * metabolismus   MeSH
• membránové potenciály MeSH
• optogenetika * MeSH
• sarkolema metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH

The neural encoding of visual features in primary visual cortex (V1) is well understood, with strong correlates to low-level perception, making V1 a strong candidate for vision restoration through neuroprosthetics. However, the functional relevance of neural dynamics evoked through external stimulation directly imposed at the cortical level is poorly understood. Furthermore, protocols for designing cortical stimulation patterns that would induce a naturalistic perception of the encoded stimuli have not yet been established. Here, we demonstrate a proof of concept by solving these issues through a computational model, combining (1) a large-scale spiking neural network model of cat V1 and (2) a virtual prosthetic system transcoding the visual input into tailored light-stimulation patterns which drive in situ the optogenetically modified cortical tissue. Using such virtual experiments, we design a protocol for translating simple Fourier contrasted stimuli (gratings) into activation patterns of the optogenetic matrix stimulator. We then quantify the relationship between spatial configuration of the imposed light pattern and the induced cortical activity. Our simulations in the absence of visual drive (simulated blindness) show that optogenetic stimulation with a spatial resolution as low as 100 [Formula: see text]m, and light intensity as weak as [Formula: see text] photons/s/cm[Formula: see text] is sufficient to evoke activity patterns in V1 close to those evoked by normal vision.

• MeSH
• lidé MeSH
• oční protézy MeSH
• optogenetika metody   MeSH
• ověření koncepční studie MeSH
• světelná stimulace metody   MeSH
• teoretické modely MeSH
• zraková percepce MeSH
• zrakové dráhy MeSH
• zrakové korové centrum fyziologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Schizophrenia research has increased in recent decades and focused more on its neural basis. Decision-making and cognitive flexibility are the main cognitive functions that are impaired and considered schizophrenia endophenotypes. Cognitive impairment was recently connected with altered functions of N-methyl-d-aspartate (NMDAR) glutamatergic receptors, which increased cortical activity. Selective NMDAR antagonists, such as MK-801, have been used to model cognitive inflexibility in schizophrenia. Decreased GABAergic inhibitory activity has been shown elsewhere with enhanced cortical activity. This imbalance in the excitatory/inhibitory may reduce the entrainment of prefrontal gamma and hippocampal theta rhythms and result in gamma/theta band de-synchronization. The current study established an acute MK-801 administration model of schizophrenia-like cognitive inflexibility in rats and used the attentional set-shifting task in which rats learned to switch/reverse the relevant rule. During the task, we used in vivo optogenetic stimulations of parvalbumin-positive interneurons at specific light pulses in the prefrontal cortex and ventral hippocampus. The first experiments showed that acute dizocilpine in rats produced schizophrenia-like cognitive inflexibility. The second set of experiments demonstrated that specific optogenetic stimulation at specific frequencies of parvalbumin-positive interneurons in the prefrontal cortex and ventral hippocampus rescued the cognitive flexibility rats that received acute MK-801. These findings advance our knowledge of the pivotal role of parvalbumin interneurons in schizophrenia-like cognitive impairment and may guide further research on this severe psychiatric disorder.

• Klíčová slova
• Attentional set-shifting task, Excitatory/inhibitory ratio, Gamma waves, MK-801, theta waves,
• MeSH
• dizocilpinmaleát * farmakologie   MeSH
• hipokampus metabolismus   MeSH
• interneurony metabolismus   MeSH
• kognice MeSH
• krysa rodu Rattus MeSH
• optogenetika MeSH
• parvalbuminy metabolismus   MeSH
• prefrontální mozková kůra metabolismus   MeSH
• receptory N-methyl-D-aspartátu metabolismus   MeSH
• schizofrenie * MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• dizocilpinmaleát * MeSH
• parvalbuminy MeSH
• receptory N-methyl-D-aspartátu MeSH

Generation of an electrochemical proton gradient is the first step of cell bioenergetics. In prokaryotes, the gradient is created by outward membrane protein proton pumps. Inward plasma membrane native proton pumps are yet unknown. We describe comprehensive functional studies of the representatives of the yet noncharacterized xenorhodopsins from Nanohaloarchaea family of microbial rhodopsins. They are inward proton pumps as we demonstrate in model membrane systems, Escherichia coli cells, human embryonic kidney cells, neuroblastoma cells, and rat hippocampal neuronal cells. We also solved the structure of a xenorhodopsin from the nanohalosarchaeon Nanosalina (NsXeR) and suggest a mechanism of inward proton pumping. We demonstrate that the NsXeR is a powerful pump, which is able to elicit action potentials in rat hippocampal neuronal cells up to their maximal intrinsic firing frequency. Hence, inwardly directed proton pumps are suitable for light-induced remote control of neurons, and they are an alternative to the well-known cation-selective channelrhodopsins.

• MeSH
• Archaea metabolismus   MeSH
• buněčné linie MeSH
• Escherichia coli metabolismus   MeSH
• koncentrace vodíkových iontů MeSH
• konformace proteinů MeSH
• lidé MeSH
• liposomy MeSH
• molekulární modely MeSH
• optogenetika * metody   MeSH
• protonové pumpy metabolismus   MeSH
• protony MeSH
• retina metabolismus   MeSH
• rodopsin chemie   metabolismus   MeSH
• spektrální analýza MeSH
• světlo MeSH
• vazba proteinů MeSH
• vazebná místa MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• liposomy MeSH
• protonové pumpy MeSH
• protony MeSH
• rodopsin MeSH

T cell activation is initiated when ligand binding to the T cell receptor (TCR) triggers intracellular phosphorylation of the TCR-CD3 complex. However, it remains unknown how biophysical properties of TCR engagement result in biochemical phosphorylation events. Here, we constructed an optogenetic tool that induces spatial clustering of ζ-chain in a light controlled manner. We showed that spatial clustering of the ζ-chain intracellular tail alone was sufficient to initialize T cell triggering including phosphorylation of ζ-chain, Zap70, PLCγ, ERK and initiated Ca2+ flux. In reconstituted COS-7 cells, only Lck expression was required to initiate ζ-chain phosphorylation upon ζ-chain clustering, which leads to the recruitment of tandem SH2 domain of Zap70 from cell cytosol to the newly formed ζ-chain clusters at the plasma membrane. Taken together, our data demonstrated the biophysical relevance of receptor clustering in TCR signaling.

• Klíčová slova
• TCR signaling, fluorescence correlation spectroscopy, optogenetics,
• MeSH
• aminokyselinové motivy MeSH
• buněčná membrána metabolismus   MeSH
• Cercopithecus aethiops MeSH
• COS buňky MeSH
• cytosol metabolismus   MeSH
• difuze MeSH
• fluorescenční spektrometrie MeSH
• fosforylace MeSH
• Jurkat buňky MeSH
• lidé MeSH
• optogenetika MeSH
• receptory antigenů T-buněk chemie   metabolismus   MeSH
• shluková analýza MeSH
• signální transdukce * MeSH
• světlo MeSH
• tyrosinkinasa p56(lck), specifická pro lymfocyty metabolismus   MeSH
• vápník metabolismus   MeSH
• zelené fluorescenční proteiny metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• LCK protein, human MeSH Prohlížeč
• receptory antigenů T-buněk MeSH
• tyrosinkinasa p56(lck), specifická pro lymfocyty MeSH
• vápník MeSH
• zelené fluorescenční proteiny MeSH

The light-gated ion channel channelrhodopsin 2 (ChR2) from Chlamydomonas reinhardtii is a major optogenetic tool. Photon absorption starts a well-characterized photocycle, but the structural basis for the regulation of channel opening remains unclear. We present high-resolution structures of ChR2 and the C128T mutant, which has a markedly increased open-state lifetime. The structure reveals two cavities on the intracellular side and two cavities on the extracellular side. They are connected by extended hydrogen-bonding networks involving water molecules and side-chain residues. Central is the retinal Schiff base that controls and synchronizes three gates that separate the cavities. Separate from this network is the DC gate that comprises a water-mediated bond between C128 and D156 and interacts directly with the retinal Schiff base. Comparison with the C128T structure reveals a direct connection of the DC gate to the central gate and suggests how the gating mechanism is affected by subtle tuning of the Schiff base's interactions.

• MeSH
• Chlamydomonas reinhardtii MeSH
• iontový transport MeSH
• kanálové rodopsiny chemie   genetika   ultrastruktura   MeSH
• konformace proteinů MeSH
• krystalografie rentgenová MeSH
• optogenetika MeSH
• sekvence aminokyselin MeSH
• sekvenční seřazení MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kanálové rodopsiny MeSH

OBJECTIVE: The aim of this comprehensive paper is to acquaint the readers with innovative approaches in the treatment of retinal diseases, which could in the coming years to get into clinical practice. Retinal prostheses, retinal pigment epithelial (RPE) transplantation, gene therapy and optogenetics will be described in this paper. METHODOLOGY: Describing the basic characteristics and mechanisms of different types of therapy and subsequently literary minireview clarifying the current state of knowledge in the area. RESULTS: Retinal prostheses, RPE transplantation, gene therapy and optogenetics offer yet unexplored possibilities and are considered as the future of treatment of retinal diseases where classical pharmacotherapy or surgical treatment are no longer sufficient. However, all these methods challenge not only in the innovative technical implementation itself, but also for the ethical, administrative and economic demands. CONCLUSION: There will be certainly interesting development in the treatment of retinal diseases, but it is not possible to fully estimate which modality of treatment will be dominant in the future.

• Klíčová slova
• gene therapy, induced pluripotent cells, optogenetics, retinal prostheses,
• MeSH
• genetická terapie MeSH
• lidé MeSH
• nemoci retiny * terapie   MeSH
• retinální pigmentový epitel * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Rhodopsins are widely distributed across all domains of life where they perform a plethora of functions through the conversion of electromagnetic radiation into physicochemical signals. As a result of an extensive survey of available genomic and metagenomic sequencing data, we reported the existence of novel clades and exotic sequence motifs scattered throughout the evolutionary radiations of both Type-1 and Type-3 rhodopsins that will likely enlarge the optogenetics toolbox. We expanded the typical rhodopsin blueprint by showing that a highly conserved and functionally important arginine residue (i.e., Arg82) was substituted multiple times during evolution by an extensive amino acid spectrum. We proposed the umbrella term Alt-rhodopsins (AltRs) for all such proteins that departed Arg82 orthodoxy. Some AltRs formed novel clades in the rhodopsin phylogeny and were found in giant viruses. Some newly uncovered AltRs were phylogenetically close to heliorhodopsins, which allowed a closer examination of the phylogenetic border between Type-1 rhodopsins and heliorhodopsins. Comprehensive phylogenetic trees and ancestral sequence reconstructions allowed us to advance the hypothesis that proto-heliorhodopsins were a eukaryotic innovation before their subsequent diversification into the extant Type-3 rhodopsins. IMPORTANCE The rhodopsin scaffold is remarkably versatile and widespread, coupling light availability to energy production and other light-dependent cellular responses with minor alterations to critical residues. We described an unprecedented spectrum of substitutions at one of the most conserved amino acids in the rhodopsin fold, Arg82. We denoted such phylogenetically diverse rhodopsins with the umbrella name Alt-rhodopsins (AltR) and described a distinct branch of AltRs in giant viruses. Intriguingly, some AltRs were the closest phylogenetic neighbors to Heliorhodopsins (HeRs) whose origins have remained enigmatic. Our analyses of HeR origins in the light of AltRs led us to posit a most unusual evolutionary trajectory that suggested a eukaryotic origin for HeRs before their diversification in prokaryotes.

• Klíčová slova
• Alt-rhodopsins, AltRs, heliorhodopsins, metagenomics, optogenetics, rhodopsins,
• MeSH
• fylogeneze MeSH
• rhodopsiny mikrobiální * genetika   MeSH
• rodopsin * genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• rhodopsiny mikrobiální * MeSH
• rodopsin * MeSH