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.

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Showing 51 - 75 of 1744 results
51.

Genetically-stable engineered optogenetic gene switches modulate spatial cell morphogenesis in two- and three-dimensional tissue cultures.

blue red EL222 PhyB/PIF6 TULIP CHO-K1 HEK293 HEK293T HeLa Transgene expression Cell death Developmental processes
Nat Commun, 2 Dec 2024 DOI: 10.1038/s41467-024-54350-7 Link to full text
Abstract: Recent advances in tissue engineering have been remarkable, yet the precise control of cellular behavior in 2D and 3D cultures remains challenging. One approach to address this limitation is to genomically engineer optogenetic control of cellular processes into tissues using gene switches that can operate with only a few genomic copies. Here, we implement blue and red light-responsive gene switches to engineer genomically stable two- and three-dimensional mammalian tissue models. Notably, we achieve precise control of cell death and morphogen-directed patterning in 2D and 3D tissues by optogenetically regulating cell necroptosis and synthetic WNT3A signaling at high spatiotemporal resolution. This is accomplished using custom-built patterned LED systems, including digital mirrors and photomasks, as well as laser techniques. These advancements demonstrate the capability of precise spatiotemporal modulation in tissue engineering and open up new avenues for developing programmable 3D tissue and organ models, with significant implications for biomedical research and therapeutic applications.
52.

Image-guided optogenetic spatiotemporal tissue patterning using μPatternScope.

blue TULIP CHO-K1 HEK293 HEK293T Transgene expression Cell death
Nat Commun, 2 Dec 2024 DOI: 10.1038/s41467-024-54351-6 Link to full text
Abstract: In the field of tissue engineering, achieving precise spatiotemporal control over engineered cells is critical for sculpting functional 2D cell cultures into intricate morphological shapes. In this study, we engineer light-responsive mammalian cells and target them with dynamic light patterns to realize 2D cell culture patterning control. To achieve this, we developed μPatternScope (μPS), a modular framework for software-controlled projection of high-resolution light patterns onto microscope samples. μPS comprises hardware and software suite governing pattern projection and microscope maneuvers. Together with a 2D culture of the engineered cells, we utilize μPS for controlled spatiotemporal induction of apoptosis to generate desired 2D shapes. Furthermore, we introduce interactive closed-loop patterning, enabling a dynamic feedback mechanism between the measured cell culture patterns and the light illumination profiles to achieve the desired target patterning trends. Our work offers innovative tools for advanced tissue engineering applications through seamless fusion of optogenetics, optical engineering, and cybernetics.
53.

Optogenetically Induced Microtubule Acetylation Unveils the Molecular Dynamics of Actin-Microtubule Crosstalk in Directed Cell Migration.

blue AsLOV2 HeLa isolated MEFs Control of cytoskeleton / cell motility / cell shape
bioRxiv, 2 Dec 2024 DOI: 10.1101/2024.12.01.626286 Link to full text
Abstract: Microtubule acetylation is implicated in regulating cell motility, yet its physiological role in directional migration and the underlying molecular mechanisms have remained unclear. This knowledge gap has persisted primarily due to a lack of tools capable of rapidly manipulating microtubule acetylation in actively migrating cells. To overcome this limitation and elucidate the causal relationship between microtubule acetylation and cell migration, we developed a novel optogenetic actuator, optoTAT, which enables precise and rapid induction of microtubule acetylation within minutes in live cells. Using optoTAT, we observed striking and rapid responses at both molecular and cellular level. First, microtubule acetylation triggers release of the RhoA activator GEF-H1 from sequestration on microtubules. This release subsequently enhances actomyosin contractility and drives focal adhesion maturation. These subcellular processes collectively promote sustained directional cell migration. Our findings position GEF-H1 as a critical molecular responder to microtubule acetylation in the regulation of directed cell migration, revealing a dynamic crosstalk between the actin and microtubule cytoskeletal networks.
54.

Dynamic heterogeneity in an E. coli stress response regulon mediates gene activation and antimicrobial peptide tolerance.

green CcaS/CcaR E. coli Endogenous gene expression Control of cell-cell / cell-material interactions
bioRxiv, 2 Dec 2024 DOI: 10.1101/2024.11.27.625634 Link to full text
Abstract: The bacterial stress response is an intricately regulated system that plays a critical role in cellular resistance to drug treatment. The complexity of this response is further complicated by cell-to-cell heterogeneity in the expression of bacterial stress response genes. These genes are often organized into networks comprising one or more transcriptional regulators that control expression of a suite of downstream genes. While the expression heterogeneity of many of these upstream regulators has been characterized, the way in which this variability affects the larger downstream stress response remains hard to predict, prompting two key questions. First, how does heterogeneity and expression noise in stress response regulators propagate to the diverse downstream genes in their regulons. Second, when expression levels vary, how do multiple downstream genes act together to protect cells from stress. To address these questions, we focus on the transcription factor PhoP, a critical virulence regulator which coordinates pathogenicity in several gram-negative species. We use optogenetic stimulation to precisely control PhoP expression levels and examine how variations in PhoP affect the downstream activation of genes in the PhoP regulon. We find that these downstream genes exhibit differences both in mean expression level and sensitivity to increasing levels of PhoP. These response functions can also vary between individual cells, increasing heterogeneity in the population. We tie these variations to cell survival when bacteria are exposed to a clinically-relevant antimicrobial peptide, showing that high expression of the PhoP-regulon gene pmrD provides a protective effect against Polymyxin B. Overall, we demonstrate that even subtle heterogeneity in expression of a stress response regulator can have clear consequences for enabling bacteria to survive stress.
55.

Optogenetic manipulation of nuclear Dorsal reveals temporal requirements and consequences for transcription.

blue AsLOV2 D. melanogaster in vivo Developmental processes
bioRxiv, 28 Nov 2024 DOI: 10.1101/2024.11.28.623729 Link to full text
Abstract: Morphogen gradients convey essential spatial information during tissue patterning. While both concentration and timing of morphogen exposure are crucial, how cells interpret these graded inputs remains challenging to address. We employed an optogenetic system to acutely and reversibly modulate the nuclear concentration of the morphogen Dorsal (DL), homologue of NF-κB, which orchestrates dorso-ventral patterning in the Drosophila embryo. By controlling DL nuclear concentration while simultaneously recording target gene outputs in real time, we identified a critical window for DL action that is required to instruct patterning, and characterized the resulting effect on spatio-temporal transcription of target genes in terms of timing, coordination, and bursting. We found that a transient decrease in nuclear DL levels at nuclear cycle 13 leads to reduced expression of the mesoderm-associated gene snail (sna) and partial derepression of the neurogenic ectoderm-associated target short gastrulation (sog) in ventral regions. Surprisingly, the mispatterning elicited by this transient change in DL is detectable at the level of single cell transcriptional bursting kinetics, specifically affecting long inter-burst durations. Our approach of using temporally-resolved and reversible modulation of a morphogen in vivo, combined with mathematical modeling, establishes a framework for understanding the stimulus-response relationships that govern embryonic patterning.
56.

A sensitive red/far-red photoswitch for controllable gene therapy in mouse models of metabolic diseases.

red DrBphP FnBphP PnBphP ATDC-5 Hana3A HEK293T HeLa hMSCs mouse in vivo Transgene expression Endogenous gene expression
Nat Commun, 27 Nov 2024 DOI: 10.1038/s41467-024-54781-2 Link to full text
Abstract: Red light optogenetic systems are in high demand for the precise control of gene expression for gene- and cell-based therapies. Here, we report a red/far-red light-inducible photoswitch (REDLIP) system based on the chimeric photosensory protein FnBphP (Fn-REDLIP) or PnBphP (Pn-REDLIP) and their interaction partner LDB3, which enables efficient dynamic regulation of gene expression with a timescale of seconds without exogenous administration of a chromophore in mammals. We use the REDLIP system to establish the REDLIP-mediated CRISPR-dCas9 (REDLIPcas) system, enabling optogenetic activation of endogenous target genes in mammalian cells and mice. The REDLIP system is small enough to support packaging into adeno-associated viruses (AAVs), facilitating its therapeutic application. Demonstrating its capacity to treat metabolic diseases, we show that an AAV-delivered Fn-REDLIP system achieved optogenetic control of insulin expression to effectively lower blood glucose levels in type 1 diabetes model mice and control an anti-obesity therapeutic protein (thymic stromal lymphopoietin, TSLP) to reduce body weight in obesity model mice. REDLIP is a compact and sensitive optogenetic tool for reversible and non-invasive control that can facilitate basic biological and biomedical research.
57.

Engineering of LOV-domains for their use as protein tags.

blue LOV domains Review
Arch Biochem Biophys, 24 Nov 2024 DOI: 10.1016/j.abb.2024.110228 Link to full text
Abstract: Light-Oxygen-Voltage (LOV) domains are the protein-based light switches used in nature to trigger and regulate various processes. They allow light signals to be converted into metabolic signaling cascades. Various LOV-domain proteins have been characterized in the last few decades and have been used to develop light-sensitive tools in cell biology research. LOV-based applications exploit the light-driven regulation of effector elements to activate signaling pathways, activate genes, or locate proteins within cells. A relatively new application of an engineered small LOV-domain protein called miniSOG (mini singlet oxygen generator) is based on the light-induced formation of reactive oxygen species (ROS). The first miniSOG was engineered from a LOV domain from Arabidopsis thaliana. This engineered 14 kDa light-responsive flavin-containing protein can be exploited as protein tag for the light-triggered localized production of ROS. Such tunable ROS production by miniSOG or similarly redesigned LOV-domains can be of use in studies focused on subcellular phenomena but may also allow new light-fueled catalytic processes. This review provides an overview of the discovery of LOV domains and their development into tools for cell biology. It also highlights recent advancements in engineering LOV domains for various biotechnological applications and cell biology studies.
58.

Red Light Responsive Cre Recombinase for Bacterial Optogenetics.

blue red PhyA/FHY1 VVD E. coli Nucleic acid editing Multichromatic
ACS Synth Biol, 19 Nov 2024 DOI: 10.1021/acssynbio.4c00388 Link to full text
Abstract: Optogenetic tools have been used in a wide range of microbial engineering applications that benefit from the tunable, spatiotemporal control that light affords. However, the majority of current optogenetic constructs for bacteria respond to blue light, limiting the potential for multichromatic control. In addition, other wavelengths offer potential benefits over blue light, including improved penetration of dense cultures and reduced potential for toxicity. In this study, we introduce OptoCre-REDMAP, a red light inducible Cre recombinase system in Escherichia coli. This system harnesses the plant photoreceptors PhyA and FHY1 and a split version of Cre recombinase to achieve precise control over gene expression and DNA excision. We optimized the design by modifying the start codon of Cre and characterized the impact of different levels of induction to find conditions that produced minimal basal expression in the dark and induced full activation within 4 h of red light exposure. We characterized the system's sensitivity to ambient light, red light intensity, and exposure time, finding OptoCre-REDMAP to be reliable and flexible across a range of conditions. In coculture experiments with OptoCre-REDMAP and the blue light responsive OptoCre-VVD, we found that the systems responded orthogonally to red and blue light inputs. Direct comparisons between red and blue light induction with OptoCre-REDMAP and OptoCre-VVD demonstrated the superior penetration properties of red light. OptoCre-REDMAP's robust and selective response to red light makes it suitable for advanced synthetic biology applications, particularly those requiring precise multichromatic control.
59.

Src kinase slows collective rotation of confined epithelial cell monolayers.

blue CRY2/CIB1 MDCK Signaling cascade control Control of cell-cell / cell-material interactions
Soft Matter, 15 Nov 2024 DOI: 10.1039/d4sm00827h Link to full text
Abstract: Collective cell migration is key during development, wound healing, and metastasis and relies on coordinated cell behaviors at the group level. Src kinase is a key signalling protein for the physiological functions of epithelia, as it regulates many cellular processes, including adhesion, motility, and mechanotransduction. Its overactivation is associated with cancer aggressiveness. Here, we take advantage of optogenetics to precisely control Src activation in time and show that its pathological-like activation slows the collective rotation of epithelial cells confined into circular adhesive patches. We interpret velocity, force, and stress data during period of non-activation and period of activation of Src thanks to a hydrodynamic description of the cell assembly as a polar active fluid. Src activation leads to a 2-fold decrease in the ratio of polar angle to friction, which could result from increased adhesiveness at the cell-substrate interface. Measuring internal stress allows us to show that active stresses are subdominant compared to traction forces. Our work reveals the importance of fine-tuning the level of Src activity for coordinated collective behaviors.
60.

Spatiotemporal control of subcellular O-GlcNAc signaling using Opto-OGT.

blue CRY2/CIB1 CRY2/CRY2 Cos-7 HEK293T Signaling cascade control
Nat Chem Biol, 14 Nov 2024 DOI: 10.1038/s41589-024-01770-7 Link to full text
Abstract: The post-translational modification of intracellular proteins through O-linked β-N-acetylglucosamine (O-GlcNAc) is a conserved regulatory mechanism in multicellular organisms. Catalyzed by O-GlcNAc transferase (OGT), this dynamic modification has an essential role in signal transduction, gene expression, organelle function and systemic physiology. Here, we present Opto-OGT, an optogenetic probe that allows for precise spatiotemporal control of OGT activity through light stimulation. By fusing a photosensitive cryptochrome protein to OGT, Opto-OGT can be robustly and reversibly activated with high temporal resolution by blue light and exhibits minimal background activity without illumination. Transient activation of Opto-OGT results in mTORC activation and AMPK suppression, which recapitulate nutrient-sensing signaling. Furthermore, Opto-OGT can be customized to localize to specific subcellular sites. By targeting OGT to the plasma membrane, we demonstrate the downregulation of site-specific AKT phosphorylation and signaling outputs in response to insulin stimulation. Thus, Opto-OGT is a powerful tool for defining the role of O-GlcNAcylation in cell signaling and physiology.
61.

Light-Induced Nanobody-Mediated Targeted Protein Degradation for Metabolic Flux Control.

blue EL222 S. cerevisiae Signaling cascade control Transgene expression
ACS Synth Biol, 11 Nov 2024 DOI: 10.1021/acssynbio.4c00552 Link to full text
Abstract: In metabolic engineering, increasing chemical production usually involves manipulating the expression levels of key enzymes. However, limited synthetic tools exist for modulating enzyme activity beyond the transcription level. Inspired by natural post-translational mechanisms, we present targeted enzyme degradation mediated by optically controlled nanobodies. We applied this method to a branched biosynthetic pathway, deoxyviolacein, and observed enhanced product specificity and yield. We then extend the biosynthesis pathway to violacein and show how simultaneous degradation of two target enzymes can further shift production profiles. Through the redirection of metabolic flux, we demonstrate how targeted enzyme degradation can be used to minimize unwanted intermediates and boost the formation of desired products.
62.

Assays to measure small molecule Hsp70 agonist activity in vitro and in vivo.

blue CRY2olig HEK293 Organelle manipulation
Anal Biochem, 9 Nov 2024 DOI: 10.1016/j.ab.2024.115712 Link to full text
Abstract: Hsp70 prevents protein aggregation and is cytoprotective, but sustained Hsp70 overexpression is problematic. Therefore, we characterized small molecule agonists that augment Hsp70 activity. Because cumbersome assays were required to assay agonists, we developed cell-based and in vivo assays in which disease-associated consequences of Hsp70 activation can be quantified. One assay uses an optogenetic system in which the formation of TDP-43 inclusions can be controlled, and the second assay employs a zebrafish model for acute kidney injury (AKI). These complementary assays will facilitate future work to identify new Hsp70 agonists as well as optimized agonist derivatives.
63.

Complex optogenetic spatial patterning with split recombinase.

blue Magnets HEK293T Transgene expression
bioRxiv, 8 Nov 2024 DOI: 10.1101/2024.11.07.622567 Link to full text
Abstract: Light is a powerful and flexible input into engineered biological systems and is particularly well-suited for spatially controlling genetic circuits. While many light-responsive molecular effectors have been developed, there remains a gap in the feasibility of using them to spatially define cell fate. We addressed this problem by employing recombinase as a sensitive light-switchable circuit element which can permanently program cell fate in response to transient illumination. We show that by combining recombinase switches with hardware for precise spatial illumination, large scale heterogeneous populations of cells can be generated in situ with high resolution. We envision that this approach will enable new types of multicellular synthetic circuit engineering where the role of initial cell patterning can be directly studied with both high throughput and tight control.
64.

Dysfunctional RNA binding protein induced neurodegeneration is attenuated by inhibition of the integrated stress response.

blue CRY2/CRY2 Neuro-2a Organelle manipulation Neuronal activity control
Biochim Biophys Acta Mol Basis Dis, 7 Nov 2024 DOI: 10.1016/j.bbadis.2024.167562 Link to full text
Abstract: Dysfunction of the RNA binding protein heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) contributes to neurodegeneration, the primary cause of permanent disability in multiple sclerosis (MS). To better understand the role of hnRNP A1 dysfunction in the pathogenesis of neurodegeneration, we utilized optogenetics-driven hnRNP A1 clustering to model its dysfunction in neuron-like differentiated Neuro-2A cells. hnRNP A1 clustering activates the integrated stress response (ISR) and results in a neurodegenerative phenotype marked by decreased neuronal protein translation and neurite loss. Small molecule inhibition of the ISR with either PERKi (GSK2606414) or ISRIB (integrated stress response inhibitor) attenuated both the decrease in neuronal translation and neurite loss, without affecting hnRNP A1 clustering. We then confirmed a strong association between hnRNP A1 clustering and ISR activation in neurons from MS brains. These data illustrate that hnRNP A1 dysfunction promotes neurodegeneration by activation of the ISR in vitro and in vivo, thus revealing a novel therapeutic target to reduce neurodegeneration and subsequent disability in MS.
65.

Drug Discovery for Diseases with High Unmet Need Through Perturbation of Biomolecular Condensates.

blue Cryptochromes LOV domains Review
J Mol Biol, 6 Nov 2024 DOI: 10.1016/j.jmb.2024.168855 Link to full text
Abstract: Biomolecular condensates (BMCs), play significant roles in organizing cellular functions in the absence of membranes through phase separation events involving RNA, proteins, and RNA-protein complexes. These membrane-less organelles form dynamic multivalent weak interactions, often involving intrinsically disordered proteins or regions (IDPs/IDRs). However, the nature of these crucial interactions, how most of these organelles are organized and are functional, remains unknown. Aberrant condensates have been implicated in neurodegenerative diseases and various cancers, presenting novel therapeutic opportunities for small molecule condensate modulators. Recent advancements in optogenetic technologies, particularly Corelet, enable precise manipulation of BMC dynamics within living cells, facilitating high-throughput screening for small molecules that target these complex structures. By elucidating the molecular mechanisms governing BMC formation and function, this innovative approach holds promise to unlock therapeutic strategies against previously "undruggable" protein targets, paving the way for effective interventions in disease.
66.

Optimizing HMG-CoA Synthase Expression for Enhanced Limonene Production in Escherichia coli through Temporal Transcription Modulation Using Optogenetics.

blue VVD E. coli in silico Endogenous gene expression
ACS Synth Biol, 5 Nov 2024 DOI: 10.1021/acssynbio.4c00432 Link to full text
Abstract: Overexpression of a single enzyme in a multigene heterologous pathway may be out of balance with the other enzymes in the pathway, leading to accumulated toxic intermediates, imbalanced carbon flux, reduced productivity of the pathway, or an inhibited growth phenotype. Therefore, optimal, balanced, and synchronized expression levels of enzymes in a particular metabolic pathway is critical to maximize production of desired compounds while maintaining cell fitness in a growing culture. Furthermore, the optimal intracellular concentration of an enzyme is determined by the expression strength, specific timing/duration, and degradation rate of the enzyme. Here, we modulated the intracellular concentration of a key enzyme, namely HMG-CoA synthase (HMGS), in the heterologous mevalonate pathway by tuning its expression level and period of transcription to enhance limonene production in Escherichia coli. Facilitated by the tuned blue-light inducible BLADE/pBad system, we observed that limonene production was highest (160 mg/L) with an intermediate transcription level of HMGS from moderate light illumination (41 au, 150 s ON/150 s OFF) throughout the growth. Owing to the easy penetration and removal of blue-light illumination from the growing culture which is hard to obtain using conventional chemical-based induction, we further explored different induction patterns of HMGS under strong light illumination (2047 au, 300 s ON) for different durations along the growth phases. We identified a specific timing of HMGS expression in the log phase (3-9 h) that led to optimal limonene production (200 mg/L). This is further supported by a mathematical model that predicts several periods of blue-light illumination (3-9 h, 0-9 h, 3-12 h, 0-12 h) to achieve an optimal expression level of HMGS that maximizes limonene production and maintains cell fitness. Compared to moderate and prolonged transcription (41 au, 150 s ON/150 s OFF, 0-73 h), strong but time-limited transcription (2047 au, 300 s ON, 3-9 h) of HMGS could maintain its optimal intracellular concentration and further increased limonene production up to 92% (250 mg/L) in the longer incubation (up to 73 h) without impacting cell fitness. This work has provided new insight into the "right amount" and "just-in-time" expression of a critical metabolite enzyme in the upper module of the mevalonate pathway using optogenetics. This study would complement previous findings in modulating HMGS expression and potentially be applicable to heterologous production of other terpenoids in E. coli.
67.

CELF2 promotes tau exon 10 inclusion via hinge domain-mediated nuclear condensation.

blue CRY2/CRY2 HEK293T Endogenous gene expression Organelle manipulation
bioRxiv, 3 Nov 2024 DOI: 10.1101/2024.11.02.621395 Link to full text
Abstract: Alternative splicing is a fundamental process that contributes to the functional diversity and complexity of proteins. The regulation of each alternative splicing event involves the coordinated action of multiple RNA-binding proteins, creating a diverse array of alternatively spliced products. Dysregulation of alternative splicing is associated with various diseases, including neurodegeneration. Here we demonstrate that CELF2, a splicing regulator and a GWAS-identified risk factor for Alzheimer’s disease, binds to mRNAs associated with neurodegenerative diseases, with a specific interaction observed in the intron adjacent to exon 10 on Tau mRNA. Loss of CELF2 in the mouse brain results in a decreased inclusion of Tau exon 10, leading to a reduced 4R:3R ratio. Further exploration shows that the hinge domain of CELF2 possesses an intrinsically disordered region (IDR), which mediates CELF2 condensation and function. The functionality of IDR in regulating CELF2 function is underscored by its substitutability with IDRs from FUS and TAF15. Using TurboID we identified proteins that interact with CELF2 through its IDR. We revealed that CELF2 co-condensate with NOVA2 and SFPQ, which coordinate with CELF2 to regulate the alternative splicing of Tau exon 10. A negatively charged residue within the IDR (D388), which is conserved among CELF proteins, is critical for CELF2 condensate formation, interactions with NOVA2 and SFPQ, and function in regulating tau exon 10 splicing. Our data allow us to propose that CELF2 regulates Tau alternative splicing by forming condensates through its IDR with other splicing factors, and that the composition of the proteins within the condensates determines the outcomes of alternative splicing events.
68.

Optogenetic patterning generates multi-strain biofilms with spatially distributed antibiotic resistance.

blue YtvA E. coli Control of cell-cell / cell-material interactions
Nat Commun, 1 Nov 2024 DOI: 10.1038/s41467-024-53546-1 Link to full text
Abstract: Spatial organization of microbes in biofilms enables crucial community function such as division of labor. However, quantitative understanding of such emergent community properties remains limited due to a scarcity of tools for patterning heterogeneous biofilms. Here we develop a synthetic optogenetic toolkit 'Multipattern Biofilm Lithography' for rational engineering and orthogonal patterning of multi-strain biofilms, inspired by successive adhesion and phenotypic differentiation in natural biofilms. We apply this toolkit to profile the growth dynamics of heterogeneous biofilm communities, and observe the emergence of spatially modulated commensal relationships due to shared antibiotic protection against the beta-lactam ampicillin. Supported by biophysical modeling, these results yield in-vivo measurements of key parameters, e.g., molecular beta-lactamase production per cell and length scale of antibiotic zone of protection. Our toolbox and associated findings provide quantitative insights into the spatial organization and distributed antibiotic protection within biofilms, with direct implications for future biofilm research and engineering.
69.

Cell-cell junctions in focus - imaging junctional architectures and dynamics at high resolution.

blue red LOV domains Phytochromes Review
J Cell Sci, 31 Oct 2024 DOI: 10.1242/jcs.262041 Link to full text
Abstract: Studies utilizing electron microscopy and live fluorescence microscopy have significantly enhanced our understanding of the molecular mechanisms that regulate junctional dynamics during homeostasis, development and disease. To fully grasp the enormous complexity of cell-cell adhesions, it is crucial to study the nanoscale architectures of tight junctions, adherens junctions and desmosomes. It is important to integrate these junctional architectures with the membrane morphology and cellular topography in which the junctions are embedded. In this Review, we explore new insights from studies using super-resolution and volume electron microscopy into the nanoscale organization of these junctional complexes as well as the roles of the junction-associated cytoskeleton, neighboring organelles and the plasma membrane. Furthermore, we provide an overview of junction- and cytoskeletal-related biosensors and optogenetic probes that have contributed to these advances and discuss how these microscopy tools enhance our understanding of junctional dynamics across cellular environments.
70.

Light-Based Juxtacrine Signaling Between Synthetic Cells.

blue iLID in vitro Control of cell-cell / cell-material interactions
Small Sci, 30 Oct 2024 DOI: 10.1002/smsc.202400401 Link to full text
Abstract: Cell signaling through direct physical cell–cell contacts plays vital roles in biology during development, angiogenesis, and immune response. Intercellular communication mechanisms between synthetic cells constructed from the bottom up are majorly reliant on diffusible chemical signals, thus limiting the range of responses in receiver cells. Engineering contact-dependent signaling between synthetic cells promises to unlock more complicated signaling schemes with spatial responses. Herein, a light-activated contact-dependent communication scheme for synthetic cells is designed and demonstrated. A split luminescent protein is utilized to limit signal generation exclusively to contact interfaces of synthetic cells, driving the recruitment of a photoswitchable protein in receiver cells, akin to juxtacrine signaling in living cells. The modular design not only demonstrates contact-dependent communication between synthetic cells but also provides a platform for engineering orthogonal contact-dependent signaling mechanisms.
71.

Light inducible gene expression system for Streptomyces.

green TtCBD Streptomyces Transgene expression
Sci Rep, 28 Oct 2024 DOI: 10.1038/s41598-024-76860-6 Link to full text
Abstract: The LitR/CarH family comprises adenosyl B12-based photosensory transcriptional regulators that control light-inducible carotenoid production in nonphototrophic bacteria. In this study, we established a blue-green light-inducible hyperexpression system using LitR and its partner ECF-type sigma factor LitS in streptomycin-producing Streptomyces griseus NBRC 13350. The constructed multiple-copy number plasmid, pLit19, carried five genetic elements: pIJ101rep, the thiostrepton resistance gene, litR, litS, and σLitS-recognized light-inducible crtE promoter. Streptomyces griseus transformants harboring pLit19 exhibited a light-dependent hyper-production of intracellular reporter enzymes including catechol-2,3-dioxygenase and β-glucuronidase, extracellular secreted enzymes including laccase and transglutaminase, and secondary metabolites including melanin, flaviolin, and indigoidine. Cephamycin-producing Streptomyces sp. NBRC 13304, carrying an entire actinorhodin gene cluster, exhibited light-dependent actinorhodin production after the introduction of the pLit19 shuttle-type plasmid with the pathway-specific activator actII-ORF4. Insertion of sti fragment derived from Streptomyces phaeochromogenes pJV1 plasmid into pLit19 increased its light sensitivity, allowing gene expression under weak light irradiation. The two constructed Escherichia coli-Streptomyces shuttle-type pLit19 plasmids were found to have abilities similar to those of pLit19. We successfully established an optogenetically controlled hyperproduction system for S. griseus NBRC 13350 and Streptomyces sp. NBRC 13304.
72.

Optogenetic dissection of transcriptional repression in a multicellular organism.

blue AsLOV2 D. melanogaster in vivo Endogenous gene expression Developmental processes
Nat Commun, 26 Oct 2024 DOI: 10.1038/s41467-024-53539-0 Link to full text
Abstract: Transcriptional control is fundamental to cellular function. However, despite knowing that transcription factors can repress or activate specific genes, how these functions are implemented at the molecular level has remained elusive, particularly in the endogenous context of developing animals. Here, we combine optogenetics, single-cell live-imaging, and mathematical modeling to study how a zinc-finger repressor, Knirps, induces switch-like transitions into long-lived quiescent states. Using optogenetics, we demonstrate that repression is rapidly reversible (~1 min) and memoryless. Furthermore, we show that the repressor acts by decreasing the frequency of transcriptional bursts in a manner consistent with an equilibrium binding model. Our results provide a quantitative framework for dissecting the in vivo biochemistry of eukaryotic transcriptional regulation.
73.

Optogenetic Control of Condensates: Principles and Applications.

blue red UV BLUF domains Cryptochromes LOV domains Phytochromes UV receptors Review
J Mol Biol, 24 Oct 2024 DOI: 10.1016/j.jmb.2024.168835 Link to full text
Abstract: Biomolecular condensates appear throughout cell physiology and pathology, but the specific role of condensation or its dynamics is often difficult to determine. Optogenetics offers an expanding toolset to address these challenges, providing tools to directly control condensation of arbitrary proteins with precision over their formation, dissolution, and patterning in space and time. In this review, we describe the current state of the field for optogenetic control of condensation. We survey the proteins and their derivatives that form the foundation of this toolset, and we discuss the factors that distinguish them to enable appropriate selection for a given application. We also describe recent examples of the ways in which optogenetic condensation has been used in both basic and applied studies. Finally, we discuss important design considerations when engineering new proteins for optogenetic condensation, and we preview future innovations that will further empower this toolset in the coming years.
74.

Optogenetically engineered Septin-7 enhances immune cell infiltration of tumor spheroids.

blue AsLOV2 Cos-7 MDA-MB-231 NK-92 primary mouse T cells Control of cytoskeleton / cell motility / cell shape Control of cell-cell / cell-material interactions
Proc Natl Acad Sci U S A, 23 Oct 2024 DOI: 10.1073/pnas.2405717121 Link to full text
Abstract: Chimeric antigen receptor T cell therapies have achieved great success in eradicating some liquid tumors, whereas the preclinical results in treating solid tumors have proven less decisive. One of the principal challenges in solid tumor treatment is the physical barrier composed of a dense extracellular matrix, which prevents immune cells from penetrating the tissue to attack intratumoral cancer cells. Here, we improve immune cell infiltration into solid tumors by manipulating septin-7 functions in cells. Using protein allosteric design, we reprogram the three-dimensional structure of septin-7 and insert a blue light-responsive light-oxygen-voltage-sensing domain 2 (LOV2), creating a light-controllable septin-7-LOV2 hybrid protein. Blue light inhibits septin-7 function in live cells, inducing extended cell protrusions and cell polarization, enhancing cell transmigration efficiency through confining spaces. We genetically edited human natural killer cell line (NK92) and mouse primary CD8+ T-cells expressing the engineered protein, and we demonstrated improved penetration and cytotoxicity against various tumor spheroid models. Our proposed strategy to enhance immune cell infiltration is compatible with other methodologies and therefore, could be used in combination to further improve cell-based immunotherapies against solid tumors.
75.

Photo-tunable hydrogels reveal cellular sensing of rapid rigidity changes through the accumulation of mechanical signaling molecules.

blue PYP CCD 841 CoN hMSCs Control of cytoskeleton / cell motility / cell shape Control of cell-cell / cell-material interactions
Cell Stem Cell, 21 Oct 2024 DOI: 10.1016/j.stem.2024.09.016 Link to full text
Abstract: Cells use traction forces to sense mechanical cues in their environment. While the molecular clutch model effectively explains how cells exert more forces on stiffer substrates, it falls short in addressing their adaptation to dynamic mechanical fluctuations prevalent in tissues and organs. Here, using hydrogel with photo-responsive rigidity, we show that cells' response to rigidity changes is frequency dependent. Strikingly, at certain frequencies, cellular traction forces exceed those on static substrates 4-fold stiffer, challenging the established molecular clutch model. We discover that the discrepancy between the rapid adaptation of traction forces and the slower deactivation of mechanotransduction signaling proteins results in their accumulation, thereby enhancing long-term cellular traction in dynamic settings. Consequently, we propose a new model that melds immediate mechanosensing with extended mechanical signaling. Our study underscores the significance of dynamic rigidity in the development of synthetic biomaterials, emphasizing the importance of considering both immediate and prolonged cellular responses.
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