Curated Optogenetic Publication Database

Search precisely and efficiently by using the advantage of the hand-assigned publication tags that allow you to search for papers involving a specific trait, e.g. a particular optogenetic switch or a host organism.

Showing 51 - 75 of 110 results
51.

Optogenetic engineering to probe the molecular choreography of STIM1-mediated cell signaling.

blue AsLOV2 CRY2/CIB1 iLID Cos-7 HEK293 HeLa Signaling cascade control Immediate control of second messengers
Nat Commun, 25 Feb 2020 DOI: 10.1038/s41467-020-14841-9 Link to full text
Abstract: Genetically encoded photoswitches have enabled spatial and temporal control of cellular events to achieve tailored functions in living cells, but their applications to probe the structure-function relations of signaling proteins are still underexplored. We illustrate herein the incorporation of various blue light-responsive photoreceptors into modular domains of the stromal interaction molecule 1 (STIM1) to manipulate protein activity and faithfully recapitulate STIM1-mediated signaling events. Capitalizing on these optogenetic tools, we identify the molecular determinants required to mediate protein oligomerization, intramolecular conformational switch, and protein-target interactions. In parallel, we have applied these synthetic devices to enable light-inducible gating of calcium channels, conformational switch, dynamic protein-microtubule interactions and assembly of membrane contact sites in a reversible manner. Our optogenetic engineering approach can be broadly applied to aid the mechanistic dissection of cell signaling, as well as non-invasive interrogation of physiological processes with high precision.
52.

An optogenetic tool for induced protein stabilization based on the Phaeodactylum tricornutum aureochrome 1a LOV domain.

blue AtLOV2 bPAC (BlaC) PtAU1-LOV in vitro S. cerevisiae Immediate control of second messengers
J Mol Biol, 24 Feb 2020 DOI: 10.1016/j.jmb.2020.02.019 Link to full text
Abstract: Control of cellular events by optogenetic tools is a powerful approach to manipulate cellular functions in a minimally invasive manner. A common problem posed by the application of optogenetic tools is to tune the activity range to be physiologically relevant. Here, we characterized a photoreceptor of the light-oxygen-voltage domain family of Phaeodactylum tricornutum aureochrome 1a (AuLOV) as a tool for increasing protein stability under blue light conditions in budding yeast. Structural studies of AuLOVwt, the variants AuLOVM254 and AuLOVW349 revealed alternative dimer association modes for the dark state, which differ from previously reported AuLOV dark state structures. Rational design of AuLOV-dimer interface mutations resulted in an optimized optogenetic tool that we fused to the photoactivatable adenylyl cyclase from Beggiatoa sp.. This synergistic light-regulation approach using two photoreceptors resulted in an optimized, photoactivatable adenylyl cyclase with a cyclic AMP production activity that matches the physiological range of Saccharomyces cerevisiae. Overall, we enlarged the optogenetic toolbox for yeast and demonstrated the importance of fine-tuning the optogenetic tool activity for successful application in cells.
53.

Non-invasive optical control of endogenous Ca2+ channels in awake mice.

blue CRY2/CRY2 CRY2clust CRY2olig HeLa mouse in vivo Immediate control of second messengers
Nat Commun, 10 Jan 2020 DOI: 10.1038/s41467-019-14005-4 Link to full text
Abstract: Optogenetic approaches for controlling Ca2+ channels provide powerful means for modulating diverse Ca2+-specific biological events in space and time. However, blue light-responsive photoreceptors are, in principle, considered inadequate for deep tissue stimulation unless accompanied by optic fiber insertion. Here, we present an ultra-light-sensitive optogenetic Ca2+ modulator, named monSTIM1 encompassing engineered cryptochrome2 for manipulating Ca2+ signaling in the brain of awake mice through non-invasive light delivery. Activation of monSTIM1 in either excitatory neurons or astrocytes of mice brain is able to induce Ca2+-dependent gene expression without any mechanical damage in the brain. Furthermore, we demonstrate that non-invasive Ca2+ modulation in neurons can be sufficiently and effectively translated into changes in behavioral phenotypes of awake mice.
54.

Primary Cilia Signaling Promotes Axonal Tract Development and Is Disrupted in Joubert Syndrome-Related Disorders Models.

blue bPAC (BlaC) CRY2/CIB1 primary mouse deep cerebellar nuclei neurons Control of cytoskeleton / cell motility / cell shape Immediate control of second messengers
Dev Cell, 16 Dec 2019 DOI: 10.1016/j.devcel.2019.11.005 Link to full text
Abstract: Appropriate axonal growth and connectivity are essential for functional wiring of the brain. Joubert syndrome-related disorders (JSRD), a group of ciliopathies in which mutations disrupt primary cilia function, are characterized by axonal tract malformations. However, little is known about how cilia-driven signaling regulates axonal growth and connectivity. We demonstrate that the deletion of related JSRD genes, Arl13b and Inpp5e, in projection neurons leads to de-fasciculated and misoriented axonal tracts. Arl13b deletion disrupts the function of its downstream effector, Inpp5e, and deregulates ciliary-PI3K/AKT signaling. Chemogenetic activation of ciliary GPCR signaling and cilia-specific optogenetic modulation of downstream second messenger cascades (PI3K, AKT, and AC3) commonly regulated by ciliary signaling receptors induce rapid changes in axonal dynamics. Further, Arl13b deletion leads to changes in transcriptional landscape associated with dysregulated PI3K/AKT signaling. These data suggest that ciliary signaling acts to modulate axonal connectivity and that impaired primary cilia signaling underlies axonal tract defects in JSRD.
55.

Optogenetic modulation of a catalytic biofilm for biotransformation of indole into tryptophan.

red BphS E. coli Immediate control of second messengers
ChemSusChem, 16 Oct 2019 DOI: 10.1002/cssc.201902413 Link to full text
Abstract: In green chemical synthesis, biofilms as biocatalysts have shown great promise. Efficient biofilm-mediated biocatalysis requires the modulation of biofilm formation. Optogenetic tools are ideal for controlling biofilms, as light is non-invasive, easily controllable and cost-efficient. In this study, we employed a near infrared (NIR) light-responsive gene circuit to modulate the cellular level of c-di-GMP, a central regulator of the prokaryote biofilm lifestyle, which allows us to regulate biofilm formation using NIR light. By applying the engineered biofilm to catalyze the biotransformation of indole into tryptophan in submerged biofilm reactors, we showed that NIR light enhanced biofilm formation to result in ~ 30% increase in tryptophan yield, which demonstrates the feasibility of applying light to modulate the formation and performance of catalytic biofilms for chemical production. The c-di-GMP targeted optogenetic approach for modulating catalytic biofilm we have demonstrated here would allow the wide application for further biofilm-mediated biocatalysis.
56.

Amelioration of Diabetes in a Murine Model upon Transplantation of Pancreatic β-Cells with Optogenetic Control of Cyclic Adenosine Monophosphate.

blue bPAC (BlaC) MIN6 Immediate control of second messengers
ACS Synth Biol, 16 Sep 2019 DOI: 10.1021/acssynbio.9b00262 Link to full text
Abstract: Pharmacological augmentation of glucose-stimulated insulin secretion (GSIS), for example, to overcome insulin resistance in type 2 diabetes is linked to suboptimal regulation of blood sugar. Cultured β-cells and islets expressing a photoactivatable adenylyl cyclase (PAC) are amenable to GSIS potentiation with light. However, whether PAC-mediated enhancement of GSIS can improve the diabetic state remains unknown. To this end, β-cells were engineered with stable PAC expression that led to over 2-fold greater GSIS upon exposure to blue light while there were no changes in the absence of glucose. Moreover, the rate of oxygen consumption was unaltered despite the photoinduced elevation of GSIS. Transplantation of these cells into streptozotocin-treated mice resulted in improved glucose tolerance, lower hyperglycemia, and higher plasma insulin when subjected to illumination. Embedding optogenetic networks in β-cells for physiologically relevant control of GSIS will enable novel solutions potentially overcoming the shortcomings of current treatments for diabetes.
57.

Compartmentalized cAMP Generation by Engineered Photoactivated Adenylyl Cyclases.

blue bPAC (BlaC) HEK293T MVD7 Signaling cascade control Immediate control of second messengers
Cell Chem Biol, 23 Jul 2019 DOI: 10.1016/j.chembiol.2019.07.004 Link to full text
Abstract: Because small-molecule activators of adenylyl cyclases (AC) affect ACs cell-wide, it is challenging to explore the signaling consequences of AC activity emanating from specific intracellular compartments. We explored this issue using a series of engineered, optogenetic, spatially restricted, photoactivable adenylyl cyclases (PACs) positioned at the plasma membrane (PM), the outer mitochondrial membrane (OMM), and the nucleus (Nu). The biochemical consequences of brief photostimulation of PAC is primarily limited to the intracellular site occupied by the PAC. By contrast, sustained photostimulation results in distal cAMP signaling. Prolonged cAMP generation at the OMM profoundly stimulates nuclear protein kinase (PKA) activity. We have found that phosphodiesterases 3 (OMM and PM) and 4 (PM) modulate proximal (local) cAMP-triggered activity, whereas phosphodiesterase 4 regulates distal cAMP activity as well as the migration of PKA's catalytic subunit into the nucleus.
58.

Using a Robust and Sensitive GFP-Based cGMP Sensor for Real Time Imaging in Intact Caenorhabditis elegans.

blue BlgC bPAC (BlaC) C. elegans in vivo Immediate control of second messengers
Genetics, 22 Jul 2019 DOI: 10.1534/genetics.119.302392 Link to full text
Abstract: cGMP plays a role in sensory signaling and plasticity by regulating ion channels, phosphodiesterases and kinases. Studies that primarily used genetic and biochemical tools suggest that cGMP is spatiotemporally regulated in multiple sensory modalities. FRET- and GFP-based cGMP sensors were developed to visualize cGMP in primary cell culture and Caenorhabditis elegans to corroborate these findings. While a FRET-based sensor has been used in an intact animal to visualize cGMP, the requirement of a multiple emission system limits its ability to be used on its own as well as with other fluorophores. Here, we demonstrate that a C. elegans codon-optimized version of the cpEGFP-based cGMP sensor FlincG3 can be used to visualize rapidly changing cGMP levels in living, behaving C. elegans We coexpressed FlincG3 with the blue light-activated guanylyl cyclases BeCyclOp and bPGC in body wall muscles and found that the rate of change in FlincG3 fluorescence correlated with the rate of cGMP production by each cyclase. Furthermore, we show that FlincG3 responds to cultivation temperature, NaCl concentration changes and sodium dodecyl sulfate in the sensory neurons AFD, ASEL/R and PHB, respectively. Intriguingly, FlincG3 fluorescence in ASEL and ASER decreased in response to a NaCl concentration upstep and downstep, respectively, which is opposite in sign to the coexpressed calcium sensor jRGECO1a and previously published calcium recordings. These results illustrate that FlincG3 can be used to report rapidly changing cGMP levels in an intact animal and that the reporter can potentially reveal unexpected spatiotemporal landscapes of cGMP in response to stimuli.
59.

Revisiting and Redesigning Light-Activated Cyclic-Mononucleotide Phosphodiesterases.

red DrBphP LAPD HEK293 in vitro Immediate control of second messengers
J Mol Biol, 10 Jul 2019 DOI: 10.1016/j.jmb.2019.07.011 Link to full text
Abstract: As diffusible second messengers, cyclic nucleoside monophosphates (cNMPs) relay and amplify molecular signals in myriad cellular pathways. The triggering of downstream physiological responses often requires defined cNMP gradients in time and space, generated through the concerted action of nucleotidyl cyclases and phosphodiesterases (PDEs). In an approach denoted optogenetics, sensory photoreceptors serve as genetically encoded, light-responsive actuators to enable the noninvasive, reversible, and spatiotemporally precise control of manifold cellular processes, including cNMP metabolism. Although nature provides efficient photoactivated nucleotidyl cyclases, light-responsive PDEs are scarce. Through modular recombination of a bacteriophytochrome photosensor and the effector of human PDE2A, we previously generated the light-activated, cNMP-specific PDE LAPD. By pursuing parallel design strategies, we here report a suite of derivative PDEs with enhanced amplitude and reversibility of photoactivation. Opposite to LAPD, far-red light completely reverts prior activation by red light in several PDEs. These improved PDEs thus complement photoactivated nucleotidyl cyclases and extend the sensitivity of optogenetics to red and far-red light. More generally, our study informs future efforts directed at designing bacteriophytochrome photoreceptors.
60.

Interneurons Regulate Locomotion Quiescence via Cyclic Adenosine Monophosphate Signaling During Stress-Induced Sleep in Caenorhabditis elegans.

red IlaC C. elegans in vivo Immediate control of second messengers Neuronal activity control
Genetics, 10 Jul 2019 DOI: 10.1534/genetics.119.302293 Link to full text
Abstract: Sleep is evolutionarily conserved, thus studying simple invertebrates such as Caenorhabditis elegans can provide mechanistic insight into sleep with single cell resolution. A conserved pathway regulating sleep across phylogeny involves cyclic adenosine monophosphate (cAMP), a ubiquitous second messenger that functions in neurons by activating protein kinase A (PKA). C. elegans sleep in response to cellular stress caused by environmental insults (stress-induced sleep (SIS)), a model for studying sleep during sickness. SIS is controlled by simple neural circuitry, thus allows for cellular dissection of cAMP signaling during sleep. We employed a red light activated adenylyl cyclase (AC), IlaC22, to identify cells involved in SIS regulation. We find that pan-neuronal activation of IlaC22 disrupts SIS through mechanisms independent of the cAMP response element binding protein (CREB). Activating IlaC22 in the single DVA interneuron, the paired RIF interneurons, and in the CEPsh glia identified these cells as wake-promoting. Using a cAMP biosensor, epac1-camps, we found that cAMP is decreased in the RIF and DVA interneurons by neuropeptidergic signaling from the ALA neuron. Ectopic over expression of sleep-promoting neuropeptides coded by flp-13 and flp-24, released from the ALA, reduced cAMP in the DVA and RIFs, respectively. Over expression of the wake-promoting neuropeptides coded by pdf-1 increased cAMP levels in the RIFs. Using a combination of optogenetic manipulation and in vivo imaging of cAMP we have identified wake-promoting neurons downstream of the neuropeptidergic output of the ALA. Our data suggest that sleep- and wake-promoting neuropeptides signal to reduce and heighten cAMP levels during sleep, respectively.
61.

Cyclic Nucleotide-Specific Optogenetics Highlights Compartmentalization of the Sperm Flagellum into cAMP Microdomains.

blue red bPAC (BlaC) LAPD HEK293 mouse sperm cells Signaling cascade control Control of cytoskeleton / cell motility / cell shape Immediate control of second messengers
Cells, 27 Jun 2019 DOI: 10.3390/cells8070648 Link to full text
Abstract: Inside the female genital tract, mammalian sperm undergo a maturation process called capacitation, which primes the sperm to navigate across the oviduct and fertilize the egg. Sperm capacitation and motility are controlled by 3',5'-cyclic adenosine monophosphate (cAMP). Here, we show that optogenetics, the control of cellular signaling by genetically encoded light-activated proteins, allows to manipulate cAMP dynamics in sperm flagella and, thereby, sperm capacitation and motility by light. To this end, we used sperm that express the light-activated phosphodiesterase LAPD or the photo-activated adenylate cyclase bPAC. The control of cAMP by LAPD or bPAC combined with pharmacological interventions provides spatiotemporal precision and allows to probe the physiological function of cAMP compartmentalization in mammalian sperm.
62.

Engineering Adenylate Cyclase Activated by Near-Infrared Window Light for Mammalian Optogenetic Applications.

red IlaC IlaM E. coli HEK293 in vitro mouse in vivo Immediate control of second messengers
ACS Synth Biol, 10 Jun 2019 DOI: 10.1021/acssynbio.8b00528 Link to full text
Abstract: Light in the near-infrared optical window (NIRW) penetrates deep through mammalian tissues, including the skull and brain tissue. Here we engineered an adenylate cyclase (AC) activated by NIRW light (NIRW-AC) and suitable for mammalian applications. To accomplish this goal, we constructed fusions of several bacteriophytochrome photosensory and bacterial AC modules using guidelines for designing chimeric homodimeric bacteriophytochromes. One engineered NIRW-AC, designated IlaM5, has significantly higher activity at 37 °C, is better expressed in mammalian cells, and can mediate cAMP-dependent photoactivation of gene expression in mammalian cells, in favorable contrast to the NIRW-ACs engineered earlier. The ilaM5 gene expressed from an AAV vector was delivered into the ventral basal thalamus region of the mouse brain, resulting in the light-controlled suppression of the cAMP-dependent wave pattern of the sleeping brain known as spindle oscillations. Reversible spindle oscillation suppression was observed in sleeping mice exposed to light from an external light source. This study confirms the robustness of principles of homodimeric bacteriophytochrome engineering, describes a NIRW-AC suitable for mammalian optogenetic applications, and demonstrates the feasibility of controlling brain activity via NIRW-ACs using transcranial irradiation.
63.

Pulsatile illumination for photobiology and optogenetics.

blue red DdPAC YtvA E. coli Immediate control of second messengers
Meth Enzymol, 26 Apr 2019 DOI: 10.1016/bs.mie.2019.04.005 Link to full text
Abstract: Living organisms exhibit a wide range of intrinsic adaptive responses to incident light. Likewise, in optogenetics, biological systems are tailored to initiate predetermined cellular processes upon light exposure. As genetically encoded, light-gated actuators, sensory photoreceptors are at the heart of these responses in both the natural and engineered scenarios. Upon light absorption, photoreceptors enter a series of generally rapid photochemical reactions leading to population of the light-adapted signaling state of the receptor. Notably, this state persists for a while before thermally reverting to the original dark-adapted resting state. As a corollary, the inactivation of photosensitive biological circuits upon light withdrawal can exhibit substantial inertia. Intermittent illumination of suitable pulse frequency can hence maintain the photoreceptor in its light-adapted state while greatly reducing overall light dose, thereby mitigating adverse side effects. Moreover, several photoreceptor systems may be actuated sequentially with a single light color if they sufficiently differ in their inactivation kinetics. Here, we detail the construction of programmable illumination devices for the rapid and parallelized testing of biological responses to diverse lighting regimes. As the technology is based on open electronics and readily available, inexpensive components, it can be adopted by most laboratories at moderate expenditure. As we exemplify for two use cases, the programmable devices enable the facile interrogation of diverse illumination paradigms and their application in optogenetics and photobiology.
64.

Optogenetic control shows that kinetic proofreading regulates the activity of the T cell receptor.

red PhyB/PIF6 Jurkat Signaling cascade control Immediate control of second messengers
Elife, 5 Apr 2019 DOI: 10.7554/elife.42475 Link to full text
Abstract: The immune system distinguishes between self and foreign antigens. The kinetic proofreading (KPR) model proposes that T cells discriminate self from foreign ligands by the different ligand binding half-lives to the T cell receptor (TCR). It is challenging to test KPR as the available experimental systems fall short of only altering the binding half-lives and keeping other parameters of the interaction unchanged. We engineered an optogenetic system using the plant photoreceptor phytochrome B (PhyB) as a ligand to selectively control the dynamics of ligand binding to the TCR by light. This opto-ligand-TCR system was combined with the unique property of PhyB to continuously cycle between the binding and non-binding states under red light, with the light intensity determining the cycling rate and thus the binding duration. Mathematical modeling of our experimental datasets showed that indeed the ligand-TCR interaction half-life is the decisive factor for activating downstream TCR signaling, substantiating KPR.
65.

Luminescence-activated nucleotide cyclase regulates spatial and temporal cAMP synthesis.

blue bPAC (BlaC) HC-1 HEK293 PCCL3 Cell cycle control Immediate control of second messengers
J Biol Chem, 17 Dec 2018 DOI: 10.1074/jbc.ac118.004905 Link to full text
Abstract: cAMP is a ubiquitous second messenger that regulates cellular proliferation, differentiation, attachment, migration, and several other processes. It has become increasingly evident that tight regulation of cAMP accumulation and localization confers divergent yet specific signaling to downstream pathways. Currently, few tools are available that have sufficient spatial and temporal resolution to study location-biased cAMP signaling. Here, we introduce a new fusion protein consisting of a light-activated adenylyl cyclase (bPAC) and luciferase (nLuc). This construct allows dual activation of cAMP production through temporally precise photostimulation or chronic chemical stimulation that can be fined-tuned to mimic physiological levels and duration of cAMP synthesis to trigger downstream events. By targeting this construct to different compartments, we show that cAMP produced in the cytosol and nucleus stimulates proliferation in thyroid cells. The bPAC-nLuc fusion construct adds a new reagent to the available toolkit to study cAMP-regulated processes in living cells.
66.

Engineering a light-responsive, quorum quenching biofilm to mitigate biofouling on water purification membranes.

blue red BphS EB1 E. coli Control of cell-cell / cell-material interactions Immediate control of second messengers Multichromatic
Sci Adv, 7 Dec 2018 DOI: 10.1126/sciadv.aau1459 Link to full text
Abstract: Quorum quenching (QQ) has been reported to be a promising approach for membrane biofouling control. Entrapment of QQ bacteria in porous matrices is required to retain them in continuously operated membrane processes and to prevent uncontrollable biofilm formation by the QQ bacteria on membrane surfaces. It would be more desirable if the formation and dispersal of biofilms by QQ bacteria could be controlled so that the QQ bacterial cells are self-immobilized, but the QQ biofilm itself still does not compromise membrane performance. In this study, we engineered a QQ bacterial biofilm whose growth and dispersal can be modulated by light through a dichromatic, optogenetic c-di-GMP gene circuit in which the bacterial cells sense near-infrared (NIR) light and blue light to adjust its biofilm formation by regulating the c-di-GMP level. We also demonstrated the potential application of the engineered light-responsive QQ biofilm in mitigating biofouling of water purification forward osmosis membranes. The c-di-GMP-targeted optogenetic approach for controllable biofilm development we have demonstrated here should prove widely applicable for designing other controllable biofilm-enabled applications such as biofilm-based biocatalysis.
67.

Potassium channel-based optogenetic silencing.

blue bPAC (BlaC) HEK293 mouse hippocampal slices mouse in vivo ND7/23 primary mouse hippocampal neurons rabbit cardiomyocytes zebrafish in vivo Immediate control of second messengers Neuronal activity control
Nat Commun, 5 Nov 2018 DOI: 10.1038/s41467-018-07038-8 Link to full text
Abstract: Optogenetics enables manipulation of biological processes with light at high spatio-temporal resolution to control the behavior of cells, networks, or even whole animals. In contrast to the performance of excitatory rhodopsins, the effectiveness of inhibitory optogenetic tools is still insufficient. Here we report a two-component optical silencer system comprising photoactivated adenylyl cyclases (PACs) and the small cyclic nucleotide-gated potassium channel SthK. Activation of this 'PAC-K' silencer by brief pulses of low-intensity blue light causes robust and reversible silencing of cardiomyocyte excitation and neuronal firing. In vivo expression of PAC-K in mouse and zebrafish neurons is well tolerated, where blue light inhibits neuronal activity and blocks motor responses. In combination with red-light absorbing channelrhodopsins, the distinct action spectra of PACs allow independent bimodal control of neuronal activity. PAC-K represents a reliable optogenetic silencer with intrinsic amplification for sustained potassium-mediated hyperpolarization, conferring high operational light sensitivity to the cells of interest.
68.

Optogenetic manipulation of intracellular calcium by BACCS promotes differentiation of MC3T3-E1 cells.

blue AsLOV2 MC3T3-E1 Cell differentiation Immediate control of second messengers
Biochem Biophys Res Commun, 27 Oct 2018 DOI: 10.1016/j.bbrc.2018.10.107 Link to full text
Abstract: Bone remodeling is maintained through the balance between bone formation by osteoblasts and bone resorption by osteoclasts. Previous studies suggested that intracellular Ca2+ signaling plays an important role in the differentiation of osteoblasts; however, the molecular mechanism of Ca2+ signaling in the differentiation of osteoblasts remains unclear. To elucidate the effect of Ca2+ signaling in osteoblasts, we employed an optogenetic tool, blue light-activated Ca2+ channel switch (BACCS). BACCS was used to spatiotemporally control intracellular Ca2+ with blue light stimulation. MC3T3-E1 cells, which have been used as a model of differentiation from preosteoblast to osteoblast, were promoted to differentiate by BACCS expression and rhythmical blue light stimulation. The results indicated that intracellular Ca2+ change from the outside of the cells can regulate signaling for differentiation of MC3T3-E1 cells. Our findings provide evidence that Ca2+ could cause osteoblast differentiation.
69.

Synthetic Light-Activated Ion Channels for Optogenetic Activation and Inhibition.

blue bPAC (BlaC) D. melanogaster in vivo rat hippocampal neurons Xenopus oocytes Immediate control of second messengers Neuronal activity control
Front Neurosci, 2 Oct 2018 DOI: 10.3389/fnins.2018.00643 Link to full text
Abstract: Optogenetic manipulation of cells or living organisms became widely used in neuroscience following the introduction of the light-gated ion channel channelrhodopsin-2 (ChR2). ChR2 is a non-selective cation channel, ideally suited to depolarize and evoke action potentials in neurons. However, its calcium (Ca2+) permeability and single channel conductance are low and for some applications longer-lasting increases in intracellular Ca2+ might be desirable. Moreover, there is need for an efficient light-gated potassium (K+) channel that can rapidly inhibit spiking in targeted neurons. Considering the importance of Ca2+ and K+ in cell physiology, light-activated Ca2+-permeant and K+-specific channels would be welcome additions to the optogenetic toolbox. Here we describe the engineering of novel light-gated Ca2+-permeant and K+-specific channels by fusing a bacterial photoactivated adenylyl cyclase to cyclic nucleotide-gated channels with high permeability for Ca2+ or for K+, respectively. Optimized fusion constructs showed strong light-gated conductance in Xenopus laevis oocytes and in rat hippocampal neurons. These constructs could also be used to control the motility of Drosophila melanogaster larvae, when expressed in motoneurons. Illumination led to body contraction when motoneurons expressed the light-sensitive Ca2+-permeant channel, and to body extension when expressing the light-sensitive K+ channel, both effectively and reversibly paralyzing the larvae. Further optimization of these constructs will be required for application in adult flies since both constructs led to eclosion failure when expressed in motoneurons.
70.

Synthetic far-red light-mediated CRISPR-dCas9 device for inducing functional neuronal differentiation.

blue red BphS CRY2/CIB1 HEK293 mouse in vivo Cell differentiation Endogenous gene expression Immediate control of second messengers
Proc Natl Acad Sci USA, 2 Jul 2018 DOI: 10.1073/pnas.1802448115 Link to full text
Abstract: The ability to control the activity of CRISPR-dCas9 with precise spatiotemporal resolution will enable tight genome regulation of user-defined endogenous genes for studying the dynamics of transcriptional regulation. Optogenetic devices with minimal phototoxicity and the capacity for deep tissue penetration are extremely useful for precise spatiotemporal control of cellular behavior and for future clinic translational research. Therefore, capitalizing on synthetic biology and optogenetic design principles, we engineered a far-red light (FRL)-activated CRISPR-dCas9 effector (FACE) device that induces transcription of exogenous or endogenous genes in the presence of FRL stimulation. This versatile system provides a robust and convenient method for precise spatiotemporal control of endogenous gene expression and also has been demonstrated to mediate targeted epigenetic modulation, which can be utilized to efficiently promote differentiation of induced pluripotent stem cells into functional neurons by up-regulating a single neural transcription factor, NEUROG2 This FACE system might facilitate genetic/epigenetic reprogramming in basic biological research and regenerative medicine for future biomedical applications.
71.

Optogenetic inhibition of Gαq protein signaling reduces calcium oscillation stochasticity.

blue CRY2/CIB1 HEK293T Signaling cascade control Immediate control of second messengers
ACS Synth Biol, 24 May 2018 DOI: 10.1021/acssynbio.8b00065 Link to full text
Abstract: As fast terminators of G-protein coupled receptor (GPCR) signaling, regulators of G-protein signaling (RGS) serve critical roles in fine-tuning second messenger levels and, consequently, cellular responses to external stimuli. Here, we report the creation of an optogenetic RGS2 (opto-RGS2) that suppresses agonist-evoked calcium oscillations by the inactivation of Gαq protein. In this system, cryptochrome-mediated hetero-dimerization of the catalytic RGS2-box with its N-terminal amphipathic helix reconstitutes a functional membrane-localized complex that can dynamically suppress store-operated release of calcium. Engineered opto-RGS2 cell lines were used to establish the role of RGS2 as a key inhibitory feedback regulator of the stochasticity of the Gαq-mediated calcium spike timing. RGS2 reduced the stochasticity of carbachol-stimulated calcium oscillations, and the feedback inhibition was coupled to the global calcium elevation by calmodulin/RGS2 interactions. The identification of a critical negative feedback circuit exemplifies the utility of optogenetic approaches for interrogating RGS/GPCR biology and calcium encoding principles through temporally precise molecular gain-of-function.
72.

Bioprinting Living Biofilms through Optogenetic Manipulation.

blue red BlrP1 BphS P. aeruginosa Control of cell-cell / cell-material interactions Immediate control of second messengers Multichromatic
ACS Synth Biol, 18 Apr 2018 DOI: 10.1021/acssynbio.8b00003 Link to full text
Abstract: In this paper, we present a new strategy for microprinting dense bacterial communities with a prescribed organization on a substrate. Unlike conventional bioprinting techniques that require bioinks, through optogenetic manipulation, we directly manipulated the behaviors of Pseudomonas aeruginosa to allow these living bacteria to autonomically form patterned biofilms following prescribed illumination. The results showed that through optogenetic manipulation, patterned bacterial communities with high spatial resolution (approximately 10 μm) could be constructed in 6 h. Thus, optogenetic manipulation greatly increases the range of available bioprinting techniques.
73.

Cyanobacteriochrome-based photoswitchable adenylyl cyclases (cPACs) for broad spectrum light regulation of cAMP levels in cells.

violet cPAC E. coli in vitro Immediate control of second messengers
J Biol Chem, 9 Apr 2018 DOI: 10.1074/jbc.ra118.002258 Link to full text
Abstract: Class III adenylyl cyclases generate the ubiquitous second messenger cAMP from ATP often in response to environmental or cellular cues. During evolution, soluble adenylyl-cyclase catalytic domains have been repeatedly juxtaposed with signal-input domains to place cAMP synthesis under the control of a wide variety of these environmental and endogenous signals. Adenylyl cyclases with light-sensing domains have proliferated in photosynthetic species depending on light as an energy source, yet are also widespread in non-photosynthetic species. Among such naturally occurring light sensors, several flavin-based photoactivated adenylyl cyclases (PACs) have been adopted as optogenetic tools to manipulate cellular processes with blue light. In this report, we report the discovery of a cyanobacteriochrome-based photoswitchable adenylyl cyclase (cPAC) from the cyanobacterium Microcoleussp. PCC 7113. Unlike flavin-dependent PACs, which must thermally decay to be deactivated, cPAC exhibited a bistable photocycle whose adenylyl cyclase could be reversibly activated and inactivated by blue and green light, respectively. Through domain exchange experiments, we also document the ability to extend the wavelength-sensing specificity of cPAC into the near IR. In summary, our work has uncovered a cyanobacteriochrome-based adenylyl cyclase that holds great potential for design of bistable photoswitchable adenylyl cyclases to fine-tune cAMP-regulated processes in cells. tissues, and whole organisms with light across the visible spectrum and into near IR.
74.

Rewiring Calcium Signaling for Precise Transcriptional Reprogramming.

blue AsLOV2 LOVTRAP HEK293T HeLa Endogenous gene expression Immediate control of second messengers
ACS Synth Biol, 6 Mar 2018 DOI: 10.1021/acssynbio.7b00467 Link to full text
Abstract: Tools capable of modulating gene expression in living organisms are very useful for interrogating the gene regulatory network and controlling biological processes. The catalytically inactive CRISPR/Cas9 (dCas9), when fused with repressive or activating effectors, functions as a versatile platform to reprogram gene transcription at targeted genomic loci. However, without temporal control, the application of these reprogramming tools will likely cause off-target effects and lack strict reversibility. To overcome this limitation, we report herein the development of a chemical or light-inducible transcriptional reprogramming device that combines photoswitchable genetically encoded calcium actuators with dCas9 to control gene expression. By fusing an engineered Ca2+-responsive NFAT fragment with dCas9 and transcriptional coactivators, we harness the power of light to achieve photoinducible transcriptional reprogramming in mammalian cells. This synthetic system (designated CaRROT) can also be used to document calcium-dependent activity in mammals after exposure to ligands or chemicals that would elicit calcium response inside cells.
75.

Optogenetics reprogramming of planktonic cells for biofilm formation.

red BphS P. aeruginosa Control of cytoskeleton / cell motility / cell shape Control of cell-cell / cell-material interactions Immediate control of second messengers
bioRxiv, 4 Dec 2017 DOI: 10.1101/229229 Link to full text
Abstract: Single-cell behaviors play essential roles during early-stage biofilms formation. In this study, we evaluated whether biofilm formation could be guided by precisely manipulating single cells behaviors. Thus, we established an illumination method to precisely manipulate the type IV pili (TFP) mediated motility and microcolony formation of Pseudomonas aeruginosa by using a combination of a high-throughput bacterial tracking algorithm, optogenetic manipulation and adaptive microscopy. We termed this method as Adaptive Tracking Illumination (ATI). We reported that ATI enables the precise manipulation of TFP mediated motility and microcolony formation during biofilm formation by manipulating bis-(3′-5′)-cyclic dimeric guanosine monophosphate (c-di-GMP) levels in single cells. Moreover, we showed that the spatial organization of single cells in mature biofilms can be controlled using ATI. Thus, the established method (i.e., ATI) can markedly promote ongoing studies of biofilms.
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