Cellular mechanical forces are regulated by Rho GTPases. Here the authors develop an optogenetic system to control the spatiotemporal activity of RhoA, and show that directing a RhoA activator to the plasma membrane causes contraction and YAP nuclear localization, whereas directing it to the mitochondria causes relaxation.
Light-controlled Biology Methods in Nature Communications
Light-controlled technologies to probe and manipulate cellular activity have revolutionized basic life science research fields ranging from cell biology to neuroscience. These technologies are also being investigated as potential therapeutic approaches for illnesses like stroke and cancer. This cross-disciplinary collection brings together Nature Communications articles from biotechnology, optics, neuroscience, cell biology, and medicine that develop or apply light-controlled technologies.
In the Cell Biology section, we highlight articles that use engineered light-sensitive proteins or new inorganic and organic optical sensors to gain insight into cellular processes such as intracellular signaling. Neuroscience is another discipline that has been revolutionized by light-controlled technologies, with optogenetics allowing neuroscientists to control genetically defined sets of neurons, and optical imaging of neuronal structure and activity during behavior becoming possible on larger scales. We highlight research and methods with especial relevance to the brain in the Neuroscience section. Although many light-controlled techniques now exist, methods developers continue to optimize and extend these non-invasive technologies (moving beyond light-control into thermo-, magneto- and sono- control), as we showcase in the Tool Development section. Finally, the Therapies section highlights Nature Communications papers that leverage light-controlled methods for disease applications.
This collection will be updated regularly with studies published in Nature Communications that feature new development and uses of light-controlled biology methods.
Cellular imaging by targeted assembly of hot-spot SERS and photoacoustic nanoprobes using split-fluorescent protein scaffolds
Traditional methods for the assembly of plasmonic nanoparticles into photo-responsive probes suffer from multiple problems. Here the authors use split fluorescent protein fragments as molecular glue to form stable nanoclusters for surface enhanced Raman scattering and photoacoustic imaging in live cells.
The International Synthetic Yeast Sc2.0 project has built Cre recombinase sites into synthetic chromosomes, enabling rapid genome evolution. Here the authors demonstrate L-SCRaMbLE, a light-controlled recombinase tool with improved control over recombination events.
Existing pH-sensitive red fluorescent protein probes don’t perform well in monitoring exocytosis and endocytosis. Here, the authors combine organic dyes with self-labeling tags or antibodies to develop semisynthetic protein conjugates that can image synaptic vesicle fusion events in living cells.
Fluorescence sensing in biological environments is prone to background signal interference. Here the authors design a photochromic fluorescent glycoprobe for light-controlled photo-switchable cell imaging and photo-activated target recognition, resulting in an increased sensing precision.
Cell-permeable organic fluorescent probes for live-cell long-term super-resolution imaging reveal lysosome-mitochondrion interactions
Studying interactions between lysosomes and mitochondria in living cells is difficult due to the limitations of existing probes. Here, the authors develop new cell-permeable fluorescent probes to image the dynamics of lysosomes and their physical interactions with mitochondria using super-resolution microscopy.
The ability to quantify the organization of cell membrane molecules is limited by the density of labeling and experimental conditions. Here, the authors use super-resolution optical fluctuation (SOFI) for molecular density and clustering analyses, and investigate nanoscale distribution of CD4 glycoprotein.
Guided morphogenesis through optogenetic activation of Rho signalling during early Drosophila embryogenesis
Optogenetics is opening the possibility to not only perturb morphogenesis, but also to guide it. Here, the authors use this technique to reconstruct epithelial folding in Drosophila embryos and study the relationship between strength of Rho activation, apical constrictions, and tissue invagination.
Changes to subsets of dendritic spines are thought to be important for memory formation. Here, the authors develop a hybrid RNA/protein tool that allows for optogenetic stimulation of single synapses that have been tagged in an activity-dependent manner
Next generation histology methods for three-dimensional imaging of fresh and archival human brain tissues
Current available tissue clearing techniques are mostly used for rodent tissues. Here, the authors develop OPTIClear solution for fresh and archival human brain tissue clearing and establish associated protocols for three-dimensional histological investigations.
An automated platform for high-throughput mouse behavior and physiology with voluntary head-fixation
Transgenic approaches and improvements in functional imaging have necessitated an advance in the behavioral toolkit. Here the authors describe an automated high-throughput voluntary head fixation system for training mice on complex psychophysical decision tasks compatible with concurrent two-photon microscopy.
Designing a norepinephrine optical tracer for imaging individual noradrenergic synapses and their activity in vivo
The noradrenergic system plays numerous physiological roles but tools to study it are scarce. Here the authors develop a fluorescent analogue of norepinephrine that can be used to label noradrenergic neurons and the synaptic vesicles, and use it to measure single synaptic vesicle release sites in living mice.
Layer-specific optogenetic activation of pyramidal neurons causes beta–gamma entrainment of neonatal networks
Oscillations in cortical activity during development are important for functional maturation. Here, the authors use optogenetics in neonatal mice to determine a causal role for pyramidal cell firing in different prelimbic cortex layers in generating beta–gamma range activity.
Bioluminescence resonance energy transfer (BRET) has been mostly employed in imaging applications. Here the authors use BRET to activate a ruthenium-based photocatalyst and perform a bioorthogonal chemical reaction, which can be used to uncage small molecule drugs in a cellular context.
Optogenetics, the optical stimulation of neurons, suffers from many technical challenges that limit the number of neurons that can be excited as well as their relative positions. Here, Pégard et al. develop a method to simultaneously stimulate an arbitrary number of neurons in 3D space with single neuron resolution.
Current approaches to thermogenetic manipulation of neuronal activity lack sufficient spatiotemporal resolution. Here the authors show that neurons expressing snake TRPA1 channels are activated at high temporal resolution with IR light and this technique can be used to elicit behaviour in zebrafish larvae.
Optogenetic applications would benefit from channelrhodopsins (ChRs) with faster photostimulation, increased tissue transparency and lower phototoxicity. Here, the authors develop fast red-shifted ChR variants and show the abilities for temporal precise spiking of cerebral interneurons and restoring auditory activity in deaf mice.
Non-destructive methods to image metabolism in situ in living tissues are limited. Here the authors combine deuterium oxide probing and stimulated Raman scattering microscopy to image lipid metabolic dynamics and protein synthesis in cells and in vivo in mice, C. elegans, and zebrafish.
Deep 2-photon imaging and artifact-free optogenetics through transparent graphene microelectrode arrays
Optical imaging and manipulation technologies cannot be easily integrated with electrical recordings due to generation of light-induced artifacts. Here the authors report the optimization of transparent graphene microelectrode fabrication to achieve artifact-free electrical recordings along with deep 2-photon imaging in vivo.
Click beetle luciferase mutant and near infrared naphthyl-luciferins for improved bioluminescence imaging
Red-shifted bioluminescence emission is needed to improve deep tissue imaging resolution. Here, the authors develop a click beetle red luciferase mutant and two naphthyl-luciferin substrates, and show the ability of the new luciferin/luciferase pairing for deep tissue multispectral tomography in mice.
Advanced diagnostic probes are required for monitoring disease progression. Here Galanzha et al. demonstrate a 22 nm plasmonic nanolaser to serve as a super-bright, biocompatible probe capable of generating stimulated emission directly inside living cells and animal tissue, while targeting cancer cells.
Current optogenetic inhibition methods like light-controlled ion pumps require high-intensity light and disrupt physiological ion gradients. Here, the authors somatically target the anion-conducting opsin GtACR to eliminate spiking in distal axons and improve photocurrents, thus enhancing its utility.
Optogenetic tools enable precise experimental control of the behaviour of cells. Here, the authors introduce a genetically-encoded two-protein system that enables silencing of excitable cells such as neurons and cardiomyocytes using blue light, and demonstrate its utility both in vitro and In vivo.
Designing split protein approaches is time consuming and often results in high background activity due to spontaneous assembly. Here the authors present an automated approach which uses a split energy scoring function to identify optimal protein split sites and reduces spontaneous assembly.
Methods to directly label active neurons are still lacking. Here the authors develop CaMPARI2, a photoconvertible fluorescent protein sensor for neuronal activity with improved brightness and calcium binding kinetics, as well as an antibody to amplify the activated sensor signal in fixed samples.
Optogenetics is a promising alternative approach for restoration of neuromuscular function. Here the authors establish a closed-loop functional optogenetic stimulation for the control of limb joint angle in murine models, which demonstrates improved control and less fatigue than electrical stimulation systems.
Noninvasive optical activation of Flp recombinase for genetic manipulation in deep mouse brain regions
Most approaches to control gene expression in vivo require generation of knock-in mouse lines and often lack spatiotemporal control. Here the authors develop a photo-activatable Flp recombinase system and demonstrate its use by controlling object-exploration behavior in mice through Cav3.1 silencing.
Stroke recovery requires circuit reorganization and therapeutic efforts have focused on rewiring cortical circuits after stroke, but what about thalamic inputs? Here, the authors examine how thalamocortical axons are affected by stroke and use optogenetic stimulation to promote recovery.
Targeting tumors with bacteria as vehicles for metabolite therapy suffers from low efficiency and robustness. Here, the authors combine carbon nitride with nitric oxide generation enzyme-positive E. coli for photo-controlled metabolite therapy (PMT) and observe increased effects both in vitro and in tumor-bearing mice.
Optogenetically stimulating intact rat corticospinal tract post-stroke restores motor control through regionalized functional circuit formation
Existing methods to improve motor function after stroke include non-specific neuromodulatory approaches. Here the authors use an automated method of analysis of reaching behaviour in rodents to show that optogenetic stimulation of intact corticospinal tract fibres leads to restoration of prior motor functions, rather than compensatory acquisition of new movements.
Impairments of spatial memory in an Alzheimer’s disease model via degeneration of hippocampal cholinergic synapses
Cholinergic neurons in the diagonal band of Broca degenerate early in Alzheimer’s disease. Here the authors show that in healthy mice, these cholinergic inputs innervate newborn neurons in the hippocampus, and that loss of this innervation in an Alzheimer’s disease model leads to impairments in spatial memory.
Top-down descending facilitation of spinal sensory excitatory transmission from the anterior cingulate cortex
It is known that descending facilitation of spinal responses may contribute to chronic pain, however many studies have focussed on brainstem mechanisms. Here the authors show that stimulation of the anterior cingulate cortex increases excitatory transmission in the dorsal horn, and that this may be via a direct pathway independent of the brainstem.