Qr: switch:"Cryptochromes"
Showing 1 - 25 of 839 results
1.
Light-induced spindle assembly through Aurora A clustering.
Abstract:
Animal cells assemble gigadalton-scale molecular complexes composed of ~200 proteins to build a functional centrosome during mitosis, ensuring faithful chromosome segregation. Although the molecular principles underlying centrosome assembly have been extensively studied, the minimal components required to reconstitute centrosome-like activity in living cells remain unknown. Here, we develop an optogenetic strategy that exploits Aurora A kinase clustering to assemble functional centrosome-like structures in human cells. Remarkably, these light-induced assemblies activate Aurora A, nucleate microtubules, and bypass the requirement for the canonical Aurora A scaffold Cep192. Mechanistically, we identify the evolutionarily conserved Aurora A partner TPX2 as an essential factor for Aurora A cluster-dependent microtubule nucleation. Furthermore, optogenetic Aurora A clustering significantly rescues spindle assembly defects associated with centrosome ablation. We term this approach Light-Induced Spindle Assembly (LISA). By directly coupling Aurora A activity to spatial clustering, LISA defines a minimal and tunable module capable of driving spindle assembly. More broadly, LISA provides a synthetic biology platform for dissecting the fundamental principles of Aurora A-dependent spindle assembly, a prominent feature of mitotic and meiotic spindle formation.
2.
Light-activated CRISPR/dCas9 nanomedicine for programmable control of renal fibrosis.
Abstract:
Renal fibrosis is the final common pathway of progressive chronic kidney disease and is maintained by spatially heterogeneous interactions among injured epithelial cells, activated fibroblasts, immune cells, extracellular matrix remodeling, metabolic stress, and persistent profibrotic transcriptional programs. Current therapies slow renal functional decline but do not directly control the regulatory circuits that stabilize maladaptive repair. Photoresponsive renal nanomedicine offers a potential strategy to add external control to anti-fibrotic intervention by combining kidney-directed delivery with light-gated release or activation of molecular payloads. This review examines the emerging interface between photoresponsive nanomaterials and CRISPR/dCas9-based gene regulation for renal fibrosis, with emphasis on upconversion nanoparticles, photoresponsive polymers, ROS- and pH-responsive matrices, optogenetic switches, and renal-compartment-directed carrier design. We argue that the most defensible therapeutic objective is not permanent genome editing or autonomous organ regeneration, but spatially confined, temporally limited, and reversible regulation of validated fibrotic or protective gene programs using CRISPRa, CRISPRi, or dCas9-based epigenome editors. The review therefore evaluates material requirements, optical-dosimetry constraints, payload architecture, renal biodistribution, target-selection logic, safety risks, and preclinical validation criteria. By defining the engineering and biological conditions required for controlled anti-fibrotic regulation, this framework positions photoresponsive renal nanomedicine as a translationally testable route toward localized modulation of fibrotic cell states rather than an overextended claim of kidney regeneration.
3.
Opto-CRISPR technologies in translational neuropharmacology.
Abstract:
Opto-CRISPR (optically controlled CRISPR/Cas) represents a major advancement in precision neurology by enabling localized gene editing within the nervous system at precise times and locations. While preclinical studies still rely largely on classical CRISPR/Cas systems, opto-CRISPR offers unprecedented opportunities to safely treat neurological diseases at their genetic roots. It achieves this by spatiotemporally correcting pathogenic mutations, halting toxic protein accumulation, repairing neurons, rebuilding neural circuitry, and accelerating drug discovery through highly realistic disease models. This review discusses this emerging field and its transformative potential for translational neuropharmacology, focusing on therapies for neurodevelopmental and neurodegenerative disorders. Opto-CRISPR is classified into four generations: Generation 1 (light-controlled Cas protein systems), Generation 2 (light-activated guide RNA systems), Generation 3 (light-controlled inhibitor systems), and Generation 4 (NIR upconversion and epigenetic multiplexing). Their working mechanisms, applications, advantages, and limitations are comprehensively described. We also critically discuss how opto-CRISPR offers distinct advantages over traditional biologics and remote modalities (e.g., small-molecule drugs, monoclonal antibodies, antisense oligonucleotides, viral-mediated gene therapy, magnetogenetics, and sonogenetics) in neuropharmacology. Finally, we address current challenges and the therapeutic outlook for the clinical translation of opto-CRISPR.
4.
Innovative Method for Evaluating the Optical Properties of Liquid-Liquid Phase Separations Using Laser Scanning Microscopic Spectroscopy.
Abstract:
Liquid-liquid phase separation (LLPS) plays a central role in intracellular compartmentalization and gene regulation. Although optogenetic optoDroplet systems are widely used to study LLPS in living cells, the mechanisms underlying the transition from dynamic liquid-like condensates to operationally defined gel-like assemblies remain poorly understood because intermediate assembly states are difficult to monitor in situ. Here, we developed a confocal laser microspectroscopy-based approach to characterize the assembly dynamics of the fused sarcomas (FUS)n-mCherry-CRY2 optoDroplet system in living NIH3T3 cells. Quantitative fluorescence analysis enabled the identification and discrimination of three distinct assembly states: monomeric, dimer/oligomer intermediate, and gel-like. Passive micro-rheology, fluorescence recovery after photobleaching (FRAP), and automated morphological analyses further demonstrated progressive reductions in molecular mobility and increasing structural rigidity during condensate maturation. Three-dimensional spatial analysis revealed that mature condensates exhibit a distinct core-shell organization consisting of an operationally defined gel-like core, a dimer/oligomer-rich intermediate layer, and an outer monomer-rich boundary layer with liquid-like properties. Upon cessation of blue-light stimulation, the outer layer rapidly dissolved, whereas the central gel-like core remained intact, indicating the acquisition of physical irreversibility. These findings establish fluorescence microspectroscopy as a quantitative approach for resolving molecular assembly states during condensate maturation and demonstrate that gelation proceeds from the condensate center toward the periphery. This framework provides new insights into pathological liquid-to-gel phase transitions associated with neurodegenerative diseases.
5.
From optical control to translational readiness: an evidence-tiered framework for optogenetics in neuromuscular and neurological disorders.
Abstract:
Optogenetics provides exceptional spatial, temporal, and cell-type specificity for manipulating biological function, but the ability to produce a light-evoked response does not by itself establish therapeutic relevance. Disease-oriented studies now span molecular assembly, neuronal excitability, neuromuscular transmission, circuit modulation, engineered human tissues, closed-loop control, and early human intervention, yet these outcomes support fundamentally different levels of inference. Here, we critically examine optogenetic applications across neuromuscular and neurological disorders and propose an evidence-tiered framework for distinguishing mechanistic causality, disease-relevant functional validation, in vivo therapeutic modulation, integrated translational system validation, and human clinical proof-of-concept. Neuromuscular disorders illustrate how optogenetics can connect molecular mechanisms and activity-dependent phenotypes to human motor-unit function, whereas studies in Parkinson's disease, Alzheimer's disease, Huntington's disease, stroke, and epilepsy primarily define causal pathways, network states, stimulation rules, and opportunities for clinically feasible neuromodulation. Human-derived motor-unit systems, organoids, and other bioengineered platforms provide important functional de-risking but should not be equated with clinical evidence. Retinal optogenetics currently provides the clearest human proof-of-concept, while its favorable anatomy limits generalization to deeper or distributed neural targets. We further show that translational progression depends on coordinated optimization of gene delivery, actuator performance, optical dosimetry, material-tissue compatibility, implant mechanics, sensing and feedback control, durability, safety, and clinically meaningful advantage over established therapies. Accordingly, optogenetic translation should be viewed as a coupled gene-material-device-control problem rather than as optical stimulation alone. This framework clarifies what different experimental designs demonstrate, where evidence remains incomplete, and which biological and engineering barriers must be resolved before optical specificity can be converted into durable clinical benefit.
6.
Nanotechnology-driven optogenetics for therapeutic grade interventions.
Abstract:
Optogenetics, a biotechnology that combines optical and genetic strategies to regulate cellular and tissue functions with high spatial and temporal precision, serves as a powerful tool-level regulatory technology widely employed to investigate cellular processes and elucidate disease mechanisms. Nanotechnology-driven optogenetics, which incorporates nanomaterials/nanostructures to improve the efficacy and broaden the applications of optogenetic systems, synergistically integrates the precision, tunability, and multifunctionality of nanotechnology with the spatiotemporal control inherent to optogenetics. The development not only enhances the flexibility and efficiency of optogenetic technology but also advances the field toward therapeutic-grade interventions. In this review, we summarize recent advances in nanotechnology-driven optogenetics, with a particular emphasis on three key areas: (1) nanostructured light sources for the precise activation of optogenetic systems, which include both externally light-stimulated systems and systems that operate independently of external light sources; (2) nanotechnology-enabled targeted delivery of light-sensitive proteins and genetic constructs to ensure efficient modulation of optogenetic pathways, which specifically involves the nanotechnology-assisted gene, protein, and recombinase enzyme delivery approaches; and (3) nanotechnology-driven therapeutic applications of optogenetics, including CAR T cell immunotherapy, cancer treatment, neurological interventions, and cardiac therapies. We further discuss the current challenges facing this emerging field and outline future research directions. This review aims not only to highlight recent breakthroughs but also to position nanotechnology-driven optogenetics as a promising tool for next-generation precision medicine.
7.
Protocol for optogenetic stimulation of cells under physical confinement.
Abstract:
Optogenetic approaches enable spatiotemporal control of signaling proteins, yet their integration with microfluidic assays to study confined cell migration remains challenging. Herein, we present a protocol for the optogenetic activation of PI3K/Akt signaling in confined cells. We detail procedures for applying stimulation to induce localized Akt activation at the cell's leading edge. This protocol enables real-time manipulation of subcellular signaling dynamics during confined migration. For additional information on the use of this protocol, please refer to Lee et al.1.
8.
A single-component optogenetic toolkit for reversible visualization and programmable control of microtubule dynamics.
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Lan, TH
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Ma, G
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Liu, X
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Duong, T
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Price, A
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Chiu, M
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Du, D
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Reiner, DJ
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Huang, Y
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Zhou, Y
Abstract:
Microtubules form dynamic cytoskeletal scaffolds essential for intracellular transport, organelle positioning, and spatial organization of signaling. Their architecture and function are continuously remodeled through the concerted actions of microtubule-associated proteins (MAPs), post-translational modifications (PTMs), and molecular motors. To precisely interrogate these processes in living systems, we developed a genetically encoded, single-component optogenetic platform for spatiotemporal control of microtubule organization and dynamics. By harnessing light-induced oligomerization to regulate microtubule association, this system supports reversible microtubule labeling and plus-end tracking, localized control of tubulin PTMs, optically regulated kinesin-driven cargo transport, and inducible microtubule severing within a unified design strategy. Using these tools, we reveal how local microtubule integrity governs lysosomal trafficking and endoplasmic reticulum (ER)-associated signaling dynamics. Collectively, this modular optogenetic toolkit bridges molecular design with cytoskeletal function, offering a versatile platform to dissect how dynamic cytoskeletal architectures coordinate intracellular organization, transport, and signaling.
9.
An optogenetic smart microscopy platform reveals signaling dynamics-dependent control over collective cell migration.
Abstract:
In cell biology, optical techniques can measure cells' internal states (biosensors) and stimulate cellular responses (optogenetics). Yet the design of all-optical experiments is often manual: a predetermined stimulus pattern is applied to cells, biosensors are measured over time, and data are processed offline. Here, we develop PyCLM, a Python-based suite enabling closed-loop measurement, image segmentation, and optogenetic control of thousands of cells per experiment. We showcase PyCLM on diverse applications, including performing feedback control on single cells and delivering developmental signaling patterns to Drosophila embryos. We compare single-cell versus tissue-scale optogenetic control of epithelial migration, revealing that fast and slow waves of receptor tyrosine kinase activity determine the direction of tissue movement, matching prior in vivo observations in zebrafish and mouse. PyCLM enables simple setup of dynamic experiments to probe cell and tissue properties and provides a first step toward real-time control of single-cell states at the tissue scale.
10.
Temporal and spatial control of phosphatidylinositides using optogenetics ameliorates behavioral deficits in an Alzheimer's disease mouse model.
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Costa, AP
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Acquarone, E
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Lazarian, A
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Herman, M
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Wartchow, KM
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Bartelo, N
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Dartora, WJ
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Krumsiek, J
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Li, XL
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Baskin, JM
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Arancio, O
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Hussaini, SA
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McIntire, LB
Abstract:
Deficits in levels of phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2] mediate Alzheimer's disease (AD) pathogenesis and etiology. The depletion of PI(4,5)P2 has been reported in AD in both human brain and animal models. Repletion of the synaptic pool of PI(4,5)P2, through haploinsufficiency of the degrading enzyme, Synaptojanin 1, ameliorated behavioral deficits in a mouse model of AD, in spite of accumulating amyloid. In order to refine the contribution of PI(4,5)P2 to AD, we used optogenetic translocation of the PI(4,5)P2-synthesizing enzyme, phosphoinositide phosphate 4 kinase2A (PIP4K2A) to the plasma membrane using light inducible dimerizable cryptochrome 2 (CRY-2) and the transcription factor CRY2-binding domain (CIBN) fused to the plasma membrane-targeting motif (CAAX). Spatiotemporally controlled production of phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2] at the plasma membrane induced amelioration of behavioral deficits in a mouse model of AD. Imaging mass spectrometry confirmed alteration of specific PI(4,5)P2 acyl species, di-oleate, indicating that precise PI(4,5)P2 species may ultimately be leveraged for therapeutic intervention.
11.
Mapping the dynamic plant interactome: from in vitro assays to in vivo quantitative approaches.
Abstract:
Protein-protein interactions underpin virtually all biological processes in plants, from signal transduction and immune responses to development and stress adaptation. Despite their fundamental importance, the plant interactome remains far from complete, and existing maps are systematically biased by the technical limitations inherent to conventional detection platforms.
12.
Astrocytic ankyrin-2 enables memory persistence in the mouse hippocampus.
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Kim, H
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Lim, J
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Kim, J
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Ozkan, E
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Kim, GH
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Park, H
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Park, MG
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Joo, B
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Lee, S
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Lee, KJ
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Kaang, BK
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Lee, CJ
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Koh, W
Abstract:
Memory persistence, the ability to retain information over time, is a fundamental feature of long-term memory. Although astrocytes contribute to synaptic plasticity, the molecular mechanisms by which they support memory persistence remain unclear. Here we show that astrocytic ankyrin-2 (Ank2) is required for memory persistence in adult mice. Astrocyte-specific deletion of Ank2 impaired remote memory without affecting recent memory and disrupted the maintenance of long-term potentiation. Loss of Ank2 reduced astrocyte contacts with engram neurons and impaired astrocyte morphogenesis driven by brain-derived neurotrophic factor (BDNF) signaling through the truncated tropomyosin receptor kinase B receptor (TrkB.T1) and inositol 1,4,5-trisphosphate receptor type 2 (IP3R2). Consistent with this mechanism, astrocytic Ank2 was required for the enhancement of memory persistence by hippocampal BDNF infusion. Furthermore, selective optogenetic activation of astrocytic TrkB.T1 signaling enhanced remote memory, demonstrating that astrocytic BDNF signaling is sufficient to promote memory persistence. These findings identify astrocytic Ank2 as a key regulator of long-term memory persistence.
13.
CD44 restricts EGFR mobility to polarize cytoskeletal signalling modules driving bleb-based migration.
Abstract:
Cells under high confinement migrate efficiently in low-adhesion environments by forming stable, polarized, hydrostatic pressure-driven leader blebs. Here we investigated the basis of polarized bleb morphology in metastatic melanoma cells migrating under low-adhesive and highly confined microenvironments. Using high-resolution live imaging, molecular perturbations and biosensors, we show that EGF signalling through PI3K stabilizes and maintains polarized leader blebs. EGFR and PI3K activities form a gradient within leader blebs that decreases from rear to front, promoting phosphatidylinositol 3,4,5-trisphosphate and Rac1-GTP accumulation at the bleb rear, whereas phosphatidylinositol 4,5-bisphosphate and RhoA-GTP concentrate at the bleb tip, the inverse of the organization observed in integrin-dependent mesenchymal migration. Optogenetic disruption of this gradient triggers bleb retraction, underscoring its functional importance. Mathematical modelling and experiments identified a mechanism whereby during bleb initiation, CD44 and ERM proteins restrict EGFR mobility within a membrane-apposed cortical actin meshwork at the bleb rear, establishing the EGFR-PI3K-Rac gradient. Together, these findings define the biophysical and molecular mechanisms that underlie polarity in bleb-based migration and highlight how alternative spatial organization of signalling modules supports distinct migration modes in different microenvironments.
14.
PIP2 stabilizes NaV1.5 gating and links receptor signaling to cardiac late sodium current.
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Gada, KD
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Kamuene, JM
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Cruz, AS
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Meng, Z
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Connolly, JG
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Ng, F
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Ma, X
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Chandrashekar, A
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Xu, Y
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Cui, M
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Plant, LD
Abstract:
The cardiac sodium channel NaV1.5 initiates each heartbeat by generating the rapid depolarizing upstroke of the action potential. Dysregulation of NaV1.5 gating can produce cardiac arrhythmias by slowing inactivation, increasing late sodium current (INa,L), and impairing electrical stability. Here, we show that phosphatidylinositol-4,5-bisphosphate (PIP2) is a critical membrane cofactor that stabilizes NaV1.5 gating. Acute PIP2 depletion in human iPSC-derived cardiomyocytes, produced by activation of endogenous AT1 receptors, activation of an engineered M3q-DREADD, or optogenetic recruitment of CRY2-pseudojanin, shifted voltage dependence, slowed fast inactivation, and increased INa,L. These effects were prevented by augmenting intracellular PIP2, required PLC activity when driven by Gq-coupled receptors, and were independent of downstream Ca2 or PKC signaling. Unlike the skeletal-muscle isoform NaV1.4, NaV1.5 displayed PIP2-dependent shifts in both activation and steady-state inactivation, indicating isoform-specific lipid coupling. Induced-fit docking and molecular dynamics simulations identified a PIP2-interaction interface between the domain IV voltage sensor and pore that contains disease-linked residues. The disease-reported variant R1644C weakened and redistributed the predicted PIP2-contact network, produced elevated basal INa,L, showed enhanced sensitivity to PIP2 depletion, and caused an approximately 30-fold reduction in apparent functional PIP2 sensitivity in excised patches. These findings define a lipid-dependent mechanism that stabilizes NaV1.5 gating and reveal how physiological Gq signaling and inherited channel variants can converge on the channel-PIP2 axis to promote proarrhythmic late sodium current.
15.
Chemically Induced Dimerization Systems: From FKBP/FRB Engineering to Expanded Biological Applications.
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Yuan, H
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Lin, S
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Lin, Z
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Li, S
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Zuo, X
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Yin, H
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Cheng, R
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Tang, Y
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Luo, Z
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Chen, M
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Zou, Q
Abstract:
The FKBP-based chemically induced dimerization (CID) technology is a fundamental tool for spatiotemporal precise modulation of protein functions in living cells, widely used in gene editing, protein function regulation, disease therapy, and drug development. However, its widespread application is limited by the inherent drawbacks including issues with immunosuppressive activity, stability, reversibility, and in vivo delivery. Recent years have seen remarkable progress in addressing these challenges: orthogonalization strategies eliminate immunosuppressive effects, fast-dissociating ligands and optogenetic systems enable reversible regulation, and protein engineering optimizes the FKBP/FRB domains to enhance stability and reduce immunogenicity. Moreover, integration with novel delivery technologies broadens its application scope greatly. This review summarizes the key optimization strategies and innovative applications of this technology in the cutting-edge biological research, aiming to reference the development of next-generation chemogenetic tools with higher precision, better safety, and greater application potential.
16.
Light-controlled CRISPR-dCas9 epigenome editing: advanced drug-delivery strategies and oncology applications.
Abstract:
Cancer is increasingly recognized as a disease of the dysregulated epigenome; however, current epi-drugs are blunt, systemically toxic instruments. Catalytically dead CRISPR nucleases (dCas9) linked to chromatin effectors have now made it possible not only to write and erase epigenetic marks at specified loci without double-strand breaks but also to add an element of optogenetics, or reversible and light-encoded control over the timing and localization of the editors. In this review, the technological underpinnings of light-controlled CRISPR-dCas9 epigenome editing, which include architectures of dCas9 scaffold and guide, blue-to-near-infrared photoswitches, and high-gain epigenetic effector designs, are synthesized, and viral, non-viral, and stimuli-responsive delivery platforms, which have to be co-optimized with clinical light interfaces, are discussed. We then outline four functional routes by which opto-epigenome editors may be used therapeutically in cancer: tumor suppressor reactivation; oncogene and super-enhancer repression with metabolic rewiring; control of cancer stem cell differentiation; and immunomodulation of the tumor microenvironment. Lastly, a translational roadmap is defined in terms of preclinical model tiers, biomarker strategies, regulatory and manufacturing factors, and future directions, including NIR and bioluminescent actuation, implantable μLED devices, and AI-guided closed-loop illumination. Together, these aspects constitute design principles for advancing light-addressable epigenome editors toward first-in-human studies and for integrating them into combination regimens as a new class of precision cancer therapeutics.
17.
Enhancing Optogenetics-Based Cancer Therapy Via Nanotechnology.
Abstract:
Optogenetics represents a promising frontier in precision cancer therapy by enabling spatiotemporal control over cellular behavior. However, its clinical application is limited by inefficient delivery of optogenetic components and poor tissue penetration of visible light. Recent advances in nanotechnology offer solutions to these challenges. Nanoscale drug delivery systems enhance the targeted delivery of optogenetic tools, while light-conversion nanomaterials enable deep-tissue activation. Besides, the integration of nanotechnology with optogenetics further facilitates the development of engineered living therapeutics, including immune cells and bacteria, allowing programmable and localized antitumor responses. Despite promising preclinical progress, key challenges remain in long-term biosafety, immunogenicity, and precise light dosing. Future progress will depend on interdisciplinary efforts combining biocompatible nanomaterials, protein engineering, and artificial intelligence to advance clinically viable optogenetic therapies and pave the way toward personalized cancer treatment. Collectively, the synergistic integration of optogenetics and nanotechnology holds potential for overcoming longstanding barriers in cancer treatment, paving the way for precision cancer therapeutics.
18.
Linear ubiquitin chain assembly complex contributes to NLRP3-mediated pyroptotic cell death.
Abstract:
Activation of the NLRP3 inflammasome by infectious or sterile insults culminates in pyroptosis, a lytic and highly inflammatory form of programmed cell death. A safeguarded two-step process tightly regulates pyroptosis: priming, which drives NF-κB signaling, followed by execution, ultimately leading to plasma membrane rupture. Linear (Met1-linked) ubiquitination, catalyzed by the E3 ligase complex LUBAC, was previously shown to participate in pyroptosis, but the underlying mechanisms are not fully understood. In this study, we show that Met1-linked ubiquitin chains can assemble during both priming and execution phases, independently of the inflammasome sensor NLRP3. Genetic deletion of the LUBAC enzymes or pharmacological inhibition impairs pyroptosis. Conversely, cell death is enhanced without the deubiquitinase OTULIN, which selectively removes linear ubiquitination. Finally, using an optogenetic model to bypass priming, we demonstrate that Met-1-linked ubiquitination is required for the execution phase of pyroptosis. These findings offer insights into the regulation of pyroptotic cell death by linear ubiquitination.
19.
Gene expression in synthetic biology: Going with the light.
Abstract:
Inducible expression of endogenous and foreign genes has been a pivotal driving force behind a lot many seminal breakthroughs in biotechnology. Synthetic biology, a very promising field, largely relies on transgene expression platforms which facilitate convenient and conditional regulation. Optogenetic approaches that exploit light to steer biological events, e.g., gene expression, with excellent spatiotemporal control, are often more precise compared to chemical induction. Light being an omnipresent environmental stimulus, serves as the ideal cue, and enables high spatiotemporal accuracy with respect to gene expression. In this review, we focus on different elements relevant to light-inducible gene expression - light-responsive promoters, light-regulated transcription factors, and photocaged inducers. Using light as a binary input function, we explore the essence of logic gates towards the development of gene expression circuits - thereby understanding the entanglement between optogenetics and synthetic biology. We primarily focus on prokaryotes, but also draw comparisons with analogous eukaryotic gene expression systems.
20.
Adhesion-driven rigidity transition decoupled from density-driven jamming triggers epithelial organization in embryonic tissues.
Abstract:
The active regulation of tissue material properties via phase transitions is central in morphogenesis. Transitions occur abruptly at critical points in different control parameters, such as cell density, shape or adhesion. Whether these parameters are interdependent, and perform redundant or distinct functions, is unknown. Here we show that depending on the co-regulation of multiple control parameters, a tissue not only tunes its deformability but also its morphogenetic trajectory. We theoretically define a phase diagram capturing the material states of zebrafish pluripotent tissues undergoing epiboly-a tissue movement occurring during gastrulation-and show that they simultaneously cross critical points in cell density, connectivity and adhesion strength. We then combine optogenetics, biophysical measurements and quantitative morphometrics to independently modulate each parameter in vivo, and identify adhesion as the main determinant of tissue rheology. Further decoupling adhesion from density and inducing adhesion-driven rigidification in unjammed pluripotent tissues is sufficient to switch their morphogenetic program and trigger epithelial organization. This switch in tissue reorganization is achieved via tricellular junction formation, followed by lumenogenesis and the initiation of apical polarity. Our work reveals that the nonlinear dynamics of emergent tissue mechanics are mechanisms of tissue organization and morphogenesis.
21.
Importin-β1 functions as a chromatin sensor to position the contractile ring for cytokinesis.
Abstract:
Cytokinesis, the final step of cell division, relies on ingression of a precisely positioned actomyosin ring. Chromatin-associated Ran-GTP fine-tunes ring position, although the mechanism remains unclear. We hypothesize that depletion of Ran-GTP between segregating chromosomes leads to equatorial enrichment of importins, promoting recruitment of the scaffold protein anillin. However, the role of importins during anaphase is not known. Here, we tested whether importins form a gradient in response to chromatin-associated Ran-GTP and regulate ring assembly in two cultured human cell lines. We endogenously tagged importin-β1 with mNeonGreen in hypotriploid HeLa cells and euploid HCT 116 cells. Live-cell imaging revealed that importin-β1 becomes transiently enriched between segregating chromosomes in anaphase HeLa cells, but not in HCT 116 cells. Using a newly developed optogenetic tool to rapidly disrupt importin-β1 function, we found that importin-β1 is required for ring ingression in HeLa cells. We speculated that the stronger requirement for importin-β1 in HeLa cells reflects differences in chromatin-to-cytosol ratio compared with HCT 116 cells, which could determine whether the Ran-GTP gradient reaches the cortex. Consistently, FLIM-FRET imaging showed that equatorially enriched importin-β1 is Ran-free in HeLa cells, but not in HCT 116 cells. A predictive model of the Ran-free importin-β1 gradient identified factors that modulate gradient formation, including chromatin-to-cytosol ratio. Experimentally decreasing or increasing the chromatin-to-cytosol ratio in HeLa and HCT 116 cells, respectively, altered importin-β1 and anillin localization to resemble the other cell type. Our findings suggest that highly aneuploid cancer cells may depend on importin-mediated anillin recruitment, representing a targetable weakness. VIDEO ABSTRACT.
22.
Inducible CRISPR/Cas systems in precision oncology: Current applications and future perspectives.
Abstract:
Inducible CRISPR/Cas systems enable spatiotemporal control of genome editing in response to chemical, optical, biological, or physical stimuli. By restricting genome-editing activity to defined conditions, these systems may reduce off-target exposure and immune burden while improving tumor-selective control, making them attractive tools for precision oncology.
23.
An Integrated Method for Photothrombotic Stroke Modeling and In Vivo Optrode Recording of Neuronal and Astrocytic Activity in Behaving Mice.
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Chen, S
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Zhang, W
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Huang, Z
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Zhang, J
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Huang, W
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Zheng, Y
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Ming, K
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Yu, L
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Yi, W
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Tang, X
Abstract:
Investigating astrocyte-neuron dynamics following ischemic stroke is essential for understanding post-stroke recovery mechanisms. However, current methodologies often fail to capture real-time interactions between neurons and astrocytes in animals executing specific behavioral tasks, limiting our ability to investigate the acute phase of stroke pathology. This protocol presents an integrated method that combines photothrombotic stroke modeling with simultaneous multichannel electrophysiology recording and fiber photometry in awake, behaving mice using a custom-fabricated optrode. The protocol includes focal ischemia induction via photothrombosis followed by simultaneous recording of neuronal spikes and astrocytic calcium transients. The optrode enables concurrent delivery of photothrombosis, calcium signal recording, and optogenetic manipulation without requiring separate surgical procedures. Representative results validate the success in simultaneous recording of astrocytic calcium signal and neuronal spiking. Optogenetic manipulation of astrocytes produces measurable changes in neuronal firing patterns (reduction in firing frequency of pyramidal neurons by 1.55 ± 0.45 Hz and interneuron by 3.64 ± 1.37 Hz compared to pre-optogenetic stimulation, n = 2), confirming that the system is capable of investigating astrocyte-neuron interactions. This integrated approach addresses critical gaps in stroke research methodology by providing real-time, multimodal recordings from the acute to chronic stage of stroke in behaving animals.
24.
Mapping the GDF15 arm of the integrated stress response in human cells and tissues.
Abstract:
Mitochondrial stress activates the integrated stress response (ISR) and triggers cell-cell communication through the secretion of the metabokine growth differentiation factor 15 (GDF15). However, the gene network underlying the ISR remains poorly defined across metabolically diverse cellular states and tissues. Using RNAseq data from fibroblasts subjected to eleven metabolic perturbations, including genetic and pharmacological mitochondrial OxPhos defects, we show that the ISR has multiple arms. To quantify the GDF15 arm of ISR activation in human cells, we developed an ISRGDF15 index. We validate the ISRGDF15 index in datasets from optogenetic and small molecule activation of ISR kinases, demonstrating its rapid kinetics preceding to GDF15 gene expression. We then deploy the ISRGDF15 index across 44 postmortem human tissues, confirm its correlation with age, and report that the ISRGDF15 is upregulated in the heart of individuals with acute causes of death in the emergency room, whereas it was upregulated in the brain of individuals who died after protracted hospital inpatient stays. These data highlight distinct arms of the ISR and clarify genes related to the GDF15 ISR arm, yielding an ISRGDF15 index that can be used to investigate tissue-specific and age-related ISR activation in both in vitro cultures and human tissues.
25.
Engineered Optogenetic Circuits In Yeast with Self-Sustained Outputs.
Abstract:
Optoswitches are of particular interest to the metabolic engineering community, as light has a superior advantage of tunability and reversibility. However, the light-shading effect at industrial scales remains an unsolved challenge. Here, we report optogenetic quorum-sensing (OptoQS) circuits to induce and maintain a sustained gene expression at the population level by transient light stimulation. In particular, we reprogram the pheromone-responsive G-protein coupled receptor (GPCR) signaling cascade in Saccharomyces cerevisiae to effectively record transient light inputs. Once the transient light input is recorded as a form of α-factor accumulation, the surrogate messenger can diffuse and transmit the signal across the cell population. Eventually, we successfully demonstrated the utility of the OptoQS circuit for metabolic regulation of 3-hydroxypropionate biosynthesis. Based on the promising results from OptoQS circuits, we envision that the flexibility of our design might be explored for the future fabrication of various genetic circuits to record other transient physical stimuli.
