Showing 51 - 75 of 1813 results
51.
Selective optogenetic inhibition of Gαq or Gαi signaling by minimal RGS domains disrupts circuit functionality and circuit formation.
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Lockyer, JL
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Reading, A
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Vicenzi, S
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Zbela, A
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Viswanathan, S
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Delandre, C
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Newland, JW
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McMullen, JPD
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Marshall, OJ
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Gasperini, R
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Foa, L
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Lin, JY
Abstract:
Optogenetic techniques provide genetically targeted, spatially and temporally precise approaches to correlate cellular activities and physiological outcomes. In the nervous system, G protein-coupled receptors (GPCRs) have essential neuromodulatory functions through binding extracellular ligands to induce intracellular signaling cascades. In this work, we develop and validate an optogenetic tool that disrupts Gαq signaling through membrane recruitment of a minimal regulator of G protein signaling (RGS) domain. This approach, Photo-induced Gα Modulator-Inhibition of Gαq (PiGM-Iq), exhibited potent and selective inhibition of Gαq signaling. Using PiGM-Iq we alter the behavior of Caenorhabditis elegans and Drosophila with outcomes consistent with GPCR-Gαq disruption. PiGM-Iq changes axon guidance in cultured dorsal root ganglia neurons in response to serotonin. PiGM-Iq activation leads to developmental deficits in zebrafish embryos and larvae resulting in altered neuronal wiring and behavior. Furthermore, by altering the minimal RGS domain, we show that this approach is amenable to Gαi signaling. Our unique and robust optogenetic Gα inhibiting approaches complement existing neurobiological tools and can be used to investigate the functional effects neuromodulators that signal through GPCR and trimeric G proteins.
52.
ERK synchronizes embryonic cleavages in Drosophila.
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Yang, L
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Zhu, A
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Aman, JM
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Denberg, D
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Kilwein, MD
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Marmion, RA
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Johnson, ANT
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Veraksa, A
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Singh, M
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Wühr, M
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Shvartsman, SY
Abstract:
Extracellular-signal-regulated kinase (ERK) signaling controls development and homeostasis and is genetically deregulated in human diseases, including neurocognitive disorders and cancers. Although the list of ERK functions is vast and steadily growing, the full spectrum of processes controlled by any specific ERK activation event remains unknown. Here, we show how ERK functions can be systematically identified using targeted perturbations and global readouts of ERK activation. Our experimental model is the Drosophila embryo, where ERK signaling at the embryonic poles has thus far only been associated with the transcriptional patterning of the future larva. Through a combination of live imaging and phosphoproteomics, we demonstrated that ERK activation at the poles is also critical for maintaining the speed and synchrony of embryonic cleavages. The presented approach to interrogating phosphorylation networks identifies a hidden function of a well-studied signaling event and sets the stage for similar studies in other organisms.
53.
Cryo-EM structures of a bathy phytochrome histidine kinase reveal a unique light-dependent activation mechanism.
Abstract:
Phytochromes are photoreceptor proteins in plants, fungi, and bacteria. They can adopt two photochromic states with differential biochemical responses. The structural changes transducing the signal from the chromophore to the biochemical output modules are poorly understood due to challenges in capturing structures of the dynamic, full-length protein. Here, we present cryoelectron microscopy (cryo-EM) structures of the phytochrome from Pseudomonas aeruginosa (PaBphP) in its resting (Pfr) and photoactivated (Pr) state. The kinase-active Pr state has an asymmetric, dimeric structure, whereas the kinase-inactive Pfr state opens up. This behavior is different from other known phytochromes and we explain it with the unusually short connection between the photosensory and output modules. Multiple sequence alignment of this region suggests evolutionary optimization for different modes of signal transduction in sensor proteins. The results establish a new mechanism for light-sensing by phytochrome histidine kinases and provide input for the design of optogenetic phytochrome variants.
54.
Programming mammalian cell behaviors by physical cues.
Abstract:
In recent decades, the field of synthetic biology has witnessed remarkable progress, driving advances in both research and practical applications. One pivotal area of development involves the design of transgene switches capable of precisely regulating specified outputs and controlling cell behaviors in response to physical cues, which encompass light, magnetic fields, temperature, mechanical forces, ultrasound, and electricity. In this review, we delve into the cutting-edge progress made in the field of physically controlled protein expression in engineered mammalian cells, exploring the diverse genetic tools and synthetic strategies available for engineering targeting cells to sense these physical cues and generate the desired outputs accordingly. We discuss the precision and efficiency limitations inherent in these tools, while also highlighting their immense potential for therapeutic applications.
55.
Genetic code expansion, click chemistry, and light-activated PI3K reveal details of membrane protein trafficking downstream of receptor tyrosine kinases.
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Koh, DS
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Stratiievska, A
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Jana, S
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Otto, SC
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Swanson, TM
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Nhim, A
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Carlson, S
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Raza, M
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Naves, LA
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Senning, EN
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Mehl, RA
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Gordon, SE
Abstract:
Ligands such as insulin, epidermal growth factor, platelet-derived growth factor, and nerve growth factor (NGF) initiate signals at the cell membrane by binding to receptor tyrosine kinases (RTKs). Along with G-protein-coupled receptors, RTKs are the main platforms for transducing extracellular signals into intracellular signals. Studying RTK signaling has been a challenge, however, due to the multiple signaling pathways to which RTKs typically are coupled, including MAP/ERK, PLCγ, and Class 1A phosphoinositide 3-kinases (PI3K). The multi-pronged RTK signaling has been a barrier to isolating the effects of any one downstream pathway. Here, we used optogenetic activation of PI3K to decouple its activation from other RTK signaling pathways. In this context, we used genetic code expansion to introduce a click chemistry noncanonical amino acid into the extracellular side of membrane proteins. Applying a cell-impermeant click chemistry fluorophore allowed us to visualize delivery of membrane proteins to the plasma membrane in real time. Using these approaches, we demonstrate that activation of PI3K, without activating other pathways downstream of RTK signaling, is sufficient to traffic the TRPV1 ion channels and insulin receptors to the plasma membrane.
56.
Optogenetic control of kinesin-1, -2, -3 and dynein reveals their specific roles in vesicular transport.
Abstract:
Each cargo in a cell employs a unique set of motor proteins for its transport. To dissect the roles of each type of motor, we developed optogenetic inhibitors of endogenous kinesin-1, -2, -3 and dynein motors and examined their effect on the transport of early endosomes, late endosomes, and lysosomes. While kinesin-1, -3, and dynein transport vesicles at all stages of endocytosis, kinesin-2 primarily drives late endosomes and lysosomes. Transient optogenetic inhibition of kinesin-1 or dynein causes both early and late endosomes to move more processively by relieving competition with opposing motors. Kinesin-2 and -3 support long-range transport, and optogenetic inhibition reduces the distances that their cargoes move. These results suggest that the directionality of transport is controlled through regulating kinesin-1 and dynein activity. On vesicles transported by several kinesin and dynein motors, modulating the activity of a single type of motor on the cargo is sufficient to direct motility.
57.
Sequential delivery of photosensitizers and checkpoint inhibitors by engineered bacteria for enhanced cancer photodynamic immunotherapy.
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Liu, X
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Fan, Y
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Zhang, X
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Li, L
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Yang, C
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Ma, X
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Bai, G
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Sun, D
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Wang, Y
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Wang, J
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Li, Y
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Shi, Y
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Liu, J
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Zhang, Y
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Wang, H
Abstract:
Engineered bacteria-based cancer therapy has increasingly been considered to be a promising therapeutic strategy due to the development of synthetic biology. Wherein, engineering bacteria-mediated photodynamic therapy (PDT)-immunotherapy shows greater advantages and potential in treatment efficiency than monotherapy. However, the unsustainable regeneration of photosensitizers (PSs) and weak immune responses limit the therapeutic efficiency. Herein, we developed an engineered bacteria-based delivery system for sequential delivery of PSs and checkpoint inhibitors in cancer PDT-immunotherapy. The biosynthetic pathway of 5-aminolevulinic acid (5-ALA) was introduced into Escherichia coli, yielding a supernatant concentration of 172.19 mg/L after 10 h of growth. And another strain was endowed with the light-controllable releasement of anti-programmed cell death-ligand 1 nanobodies (anti-PD-L1). This system exhibited a collaborative effect, where PDT initiated tumor cell death and the released tumor cell fragments stimulated immunity, followed by the elimination of residual tumor cells. The tumor inhibition rate reached 74.97%, and the portion of activated T cells and inflammatory cytokines were reinforced. The results demonstrated that the engineered bacteria-based collaborative system could sequentially deliver therapeutic substance and checkpoint inhibitors, and achieve good therapeutic therapy. This paper will provide a new perspective for the cancer PDT-immunotherapy.
58.
Optogenetic tools for inducing organelle membrane rupture.
Abstract:
Disintegration of organelle membranes induces various cellular responses and has pathological consequences, including autoinflammatory diseases and neurodegeneration. Establishing methods to induce membrane rupture of organelles of interest is essential to analyze the downstream effects of membrane rupture; however, the spatiotemporal induction of rupture of specific membranes remains challenging. Here, we develop a series of optogenetic tools to induce organelle membrane rupture by using engineered Bcl-2-associated X protein (BAX), whose primary function is to form membrane pores in the outer mitochondrial membrane (OMM) during apoptosis. When BAX is forced to target mitochondria, lysosomes, or the endoplasmic reticulum (ER) by replacing its C-terminal transmembrane domain (TMD) with organelle-targeting sequences, the BAX mutants rupture their target membranes. To regulate the activity of organelle-targeted BAX, the photosensitive light-oxygen-voltage-sensing 2 (LOV2) domain is fused to the N-terminus of BAX. The resulting LOV2–BAX fusion protein exhibits blue light–dependent membrane-rupture activity on various organelles, including mitochondria, the ER, and lysosomes. Thus, LOV2–BAX enables spatiotemporal induction of membrane rupture across a broad range of organelles, expanding research opportunities on the consequences of organelle membrane disruption.
59.
Bacteria-based cascade in situ near-infrared nano-optogenetically induced photothermal tumor therapy.
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Hu, X
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Chen, J
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Qiu, Y
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Chen, S
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Liu, Y
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Yu, X
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Liu, Y
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Yang, X
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Zhang, Y
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Zhu, Y
Abstract:
Rationale: Optogenetically engineered facultative anaerobic bacteria exhibit a favorable tendency to colonize at solid tumor sites and spatiotemporally-programmable therapeutics release abilities, attracting extensive attention in precision tumor therapy. However, their therapeutic efficacy is moderate. Conventional photothermal agents with high tumor ablation capabilities exhibit low tumor targeting efficiency, resulting in significant off-target side effects. The combination of optogenetics and photothermal therapy may offer both tumor-targeting and excellent tumor-elimination capabilities, which unfortunately has rarely been investigated. Herein, we construct a bacteria-based cascade near-infrared optogentical-photothermal system (EcNαHL-UCNPs) for enhanced tumor therapy. Methods: EcNαHL-UCNPs consists of an optogenetically engineered Escherichia coli Nissle 1917 (EcN) conjugated with lanthanide-doped upconversion nanoparticles (UCNPs), which are capable of locally secreting α-hemolysin (αHL), a pore-forming protein, in responsive to NIR irradiation. Anti-tumor effects of EcNαHL-UCNPs were determined in both H22 and 4T1 tumors. Results: The αHL not only eliminates tumor cells, but more importantly disrupts endothelium to form thrombosis as an in situ photothermal agent in tumors. The in situ formed thrombosis significantly potentiates the photothermic ablation of H22 tumors upon subsequent NIR light irradiation. Besides, αHL secreted by EcNαHL-UCNPs under NIR light irradiation not only inhibits 4T1 tumor growth, but also suppresses metastasis of 4T1 tumor via inducing the immune response. Conclusion: Our studies highlight bacteria-based cascade optogenetical-photothermal system for precise and effective tumor therapy.
60.
Induction of bacterial expression at the mRNA level by light.
Abstract:
Vital organismal processes, including development, differentiation and adaptation, involve altered gene expression. Although expression is frequently controlled at the transcriptional stage, various regulation mechanisms operate at downstream levels. Here, we leverage the photoreceptor NmPAL to optogenetically induce RNA refolding and the translation of bacterial mRNAs. Blue-light-triggered NmPAL binding disrupts a cis-repressed mRNA state, thereby relieves obstruction of translation initiation, and upregulates gene expression. Iterative probing and optimization of the circuit, dubbed riboptoregulator, enhanced induction to 30-fold. Given action at the mRNA level, the riboptoregulator can differentially regulate individual structural genes within polycistronic operons. Moreover, it is orthogonal to and can be wed with other gene-regulatory circuits for nuanced and more stringent gene-expression control. We thus advance the pAurora2 circuit that combines transcriptional and translational mechanisms to optogenetically increase bacterial gene expression by >1000-fold. The riboptoregulator strategy stands to upgrade numerous regulatory circuits and widely applies to expression control in microbial biotechnology, synthetic biology and materials science.
61.
Prior Fc receptor activation primes macrophages for increased sensitivity to IgG via long-term and short-term mechanisms.
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Bond, A
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Fiaz, S
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Rollins, K
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Nario, JEQ
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Snyder, ET
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Atkins, DJ
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Rosen, SJ
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Granados, A
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Dey, SS
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Wilson, MZ
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Morrissey, MA
Abstract:
Macrophages measure the "eat-me" signal immunoglobulin G (IgG) to identify targets for phagocytosis. We tested whether prior encounters with IgG influence macrophage appetite. IgG is recognized by the Fc receptor. To temporally control Fc receptor activation, we engineered an Fc receptor that is activated by the light-induced oligomerization of Cry2, triggering phagocytosis. Using this tool, we demonstrate that subthreshold Fc receptor activation primes mouse bone-marrow-derived macrophages to be more sensitive to IgG in future encounters. Macrophages that have previously experienced subthreshold Fc receptor activation eat more IgG-bound human cancer cells. Increased phagocytosis occurs by two discrete mechanisms-a short- and long-term priming. Long-term priming requires new protein synthesis and Erk activity. Short-term priming does not require new protein synthesis and correlates with an increase in Fc receptor mobility. Our work demonstrates that IgG primes macrophages for increased phagocytosis, suggesting that therapeutic antibodies may become more effective after initial priming doses.
62.
Dimerization activates the Inversin complex in C. elegans.
Abstract:
Genetic, colocalization, and biochemical studies suggest that the ankyrin repeat-containing proteins Inversin (INVS) and ANKS6 function with the NEK8 kinase to control tissue patterning and maintain organ physiology. It is unknown whether these three proteins assemble into a static “Inversin complex” or one that adopts multiple bioactive forms. Through characterization of hyperactive alleles in C. elegans, we discovered that the Inversin complex is activated by dimerization. Genome engineering of an RFP tag onto the nematode homologues of INVS (MLT-4) and NEK8 (NEKL-2) induced a gain-of-function, cyst-like phenotype that was suppressed by monomerization of the fluorescent tag. Stimulated dimerization of MLT-4 or NEKL-2 using optogenetics was sufficient to recapitulate the phenotype of a constitutively active Inversin complex. Further, dimerization of NEKL-2 bypassed a lethal MLT-4 mutant, demonstrating that the dimeric form is required for function. We propose that dynamic switching between at least two functionally distinct states–-an active dimer and an inactive monomer–-gates the output of the Inversin complex.
63.
Rapid and reversible dissolution of biomolecular condensates using light-controlled recruitment of a solubility tag.
Abstract:
Biomolecular condensates are broadly implicated in both normal cellular regulation and disease. Consequently, several chemical biology and optogenetic approaches have been developed to induce phase separation of a protein of interest. However, few tools are available to perform the converse function - dissolving a condensate of interest on demand. Such a tool would aid in testing whether the condensate plays specific functional roles. Here we show that light-gated recruitment of a solubilizing domain, maltose-binding protein (MBP), results in rapid and controlled dissolution of condensates formed from proteins of interest. Our optogenetic MBP-based dissolution strategy (OptoMBP) is rapid, reversible, and can be spatially controlled with subcellular precision. We also provide a proof-of-principle application of OptoMBP by disrupting condensation of the oncogenic fusion protein FUS-CHOP and reverting FUS-CHOP driven transcriptional changes. We envision that the OptoMBP system could be broadly useful for disrupting constitutive protein condensates to probe their biological functions.
64.
Stress pathway outputs are encoded by pH-dependent clustering of kinase components.
Abstract:
Signal processing by intracellular kinases controls near all biological processes but how signal pathway functions evolve with changed cellular context is poorly understood. Functional specificity of c-Jun N-terminal Kinases (JNK) are partly encoded by signal strength. Here we reveal that intracellular pH (pHi) is a significant component of the JNK network and defines signal response to specific stimuli. We show pHi regulates JNK activity in response to cell stress, with the relationship between pHi and JNK activity dependent on specific stimuli and upstream kinases activated. Using the optogenetic clustering tag CRY2, we show that an increase in pHi promotes the light-induced phase transition of ASK1 to augment JNK activation. While increased pHi similarly promoted CRY2-tagged JNK2 to form light-induced condensates, this attenuated JNK activity. Mathematical modelling of feedback signalling incorporating pHi and differential contributions by ASK1 and JNK2 condensates was sufficient to delineate signal responses to specific stimuli. Taking pHi and ASK1/JNK2 signal contributions into consideration may delineate oncogenic versus tumour suppressive JNK functions and cancer cell drug responses.
65.
Optogenetic control of phosphate-responsive genes using single component fusion proteins in Saccharomyces cerevisiae.
Abstract:
Blue light illumination can be detected by Light-Oxygen-Voltage (LOV) photosensing proteins and translated into a range of biochemical responses, facilitating the generation of novel optogenetic tools to control cellular function. Here we develop new variants of our previously described VP-EL222 light-dependent transcription factor and apply them to study the phosphate-responsive signaling (PHO) pathway in the budding yeast Saccharomyces cerevisiae, exemplifying the utilities of these new tools. Focusing first on the VP-EL222 protein itself, we quantified the tunability of gene expression as a function of light intensity and duration, and demonstrated that this system can tolerate the addition of substantially larger effector domains without impacting function. We further demonstrated the utility of several EL222-driven transcriptional controllers in both plasmid and genomic settings, using the PHO5 and PHO84 promoters in their native chromosomal contexts as examples. These studies highlight the utility of light-controlled gene activation using EL222 tethered to either artificial transcription domains or yeast activator proteins (Pho4). Similarly, we demonstrate the ability to optogenetically repress gene expression with EL222 fused to the yeast Ume6 protein. We finally investigated the effects of moving EL222 recruitment sites to different locations within the PHO5 and PHO84 promoters, as well as determining how this artificial light-controlled regulation could be integrated with the native controls dependent on inorganic phosphate (Pi) availability. Taken together, our work expands the applicability of these versatile optogenetic tools in the types of functionality they can deliver and biological questions that can be probed.
66.
Optogenetic inhibition of light-captured alcohol-taking striatal engrams facilitates extinction and suppresses reinstatement.
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Vierkant, V
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Xie, X
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Huang, Z
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He, L
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Bancroft, E
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Wang, X
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Nguyen, T
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Srinivasan, R
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Zhou, Y
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Wang, J
Abstract:
Alcohol use disorder (AUD) is a complex condition, and it remains unclear which specific neuronal substrates mediate alcohol-seeking and -taking behaviors. Engram cells and their related ensembles, which encode learning and memory, may play a role in this process. We aimed to assess the precise neural substrates underlying alcohol-seeking and -taking behaviors and determine how they may affect one another.
67.
Notch1 Phase Separation Coupled Percolation facilitates target gene expression and enhancer looping.
Abstract:
The Notch receptor is a pleiotropic signaling protein that translates intercellular ligand interactions into changes in gene expression via the nuclear localization of the Notch intracellular Domain (NICD). Using a combination of immunohistochemistry, RNA in situ, Optogenetics and super-resolution live imaging of transcription in human cells, we show that the N1ICD can form condensates that positively facilitate Notch target gene expression. We determined that N1ICD undergoes Phase Separation Coupled Percolation (PSCP) into transcriptional condensates, which recruit, enrich, and encapsulate a broad set of core transcriptional proteins. We show that the capacity for condensation is due to the intrinsically disordered transcriptional activation domain of the N1ICD. In addition, the formation of such transcriptional condensates acts to promote Notch-mediated super enhancer-looping and concomitant activation of the MYC protooncogene expression. Overall, we introduce a novel mechanism of Notch1 activity in which discrete changes in nuclear N1ICD abundance are translated into the assembly of transcriptional condensates that facilitate gene expression by enriching essential transcriptional machineries at target genomic loci.
68.
Reshaping tumor microenvironment by regulating local cytokines expression with a portable smart blue-light controlled device.
Abstract:
Cytokines have attracted sustained attention due to their multi-functional cellular response in immunotherapy. However, their application was limited to their short half-time, narrow therapeutic window, and undesired side effects. To address this issue, we developed a portable smart blue-light controlled (PSLC) device based on optogenetic technology. By combining this PSLC device with blue-light controlled gene modules, we successfully achieved the targeted regulation of cytokine expression within the tumor microenvironment. To alter the tumor microenvironment of solid tumors, pro-inflammatory cytokines were selected as blue-light controlled molecules. The results show that blue-light effectively regulates the expression of pro-inflammatory cytokines both in vitro and in vivo. This strategy leads to enhanced and activated tumor-infiltrating immune cells, which facilitated to overcome the immunosuppressive microenvironment, resulting in significant tumor shrinkage in tumor-bearing mice. Hence, our study offers a unique strategy for cytokine therapy and a convenient device for animal studies in optogenetic immunotherapy.
69.
Optogenetic Strategies for Optimizing the Performance of Phospholipids Biosensors.
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Yao, Y
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Lou, X
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Jin, L
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Sun, W
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Liu, J
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Chen, Y
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Cheng, S
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Zhao, T
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Ke, S
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Zhang, L
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Xu, Y
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He, L
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Li, H
Abstract:
High-performance biosensors play a crucial role in elucidating the intricate spatiotemporal regulatory roles and dynamics of membrane phospholipids. However, enhancing the sensitivity and imaging performance remains a significant challenge. Here, optogenetic-based strategies are presented to optimize phospholipid biosensors. These strategies involves presequestering unbound biosensors in the cell nucleus and regulating their cytosolic levels with blue light to minimize background signal interference in phospholipid detection, particularly under conditions of high expression levels of biosensor. Furthermore, optically controlled phase separation and the SunTag system are employed to generate punctate probes for substrate detection, thereby amplifying biosensor signals and enhancing visualization of the detection process. These improved phospholipid biosensors hold great potential for enhancing the understanding of the spatiotemporal dynamics and regulatory roles of membrane lipids in live cells and the methodological insights in this study might be valuable for developing other high-performance biosensors.
70.
An Integrated Optogenetic and Bioelectronic Platform for Regulating Cardiomyocyte Function.
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Bolonduro, OA
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Chen, Z
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Fucetola, CP
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Lai, YR
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Cote, M
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Kajola, RO
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Rao, AA
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Liu, H
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Tzanakakis, ES
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Timko, BP
Abstract:
Bioelectronic medicine is emerging as a powerful approach for restoring lost endogenous functions and addressing life-altering maladies such as cardiac disorders. Systems that incorporate both modulation of cellular function and recording capabilities can enhance the utility of these approaches and their customization to the needs of each patient. Here is report an integrated optogenetic and bioelectronic platform for stable and long-term stimulation and monitoring of cardiomyocyte function in vitro. Optical inputs are achieved through the expression of a photoactivatable adenylyl cyclase, that when irradiated with blue light causes a dose-dependent and time-limited increase in the secondary messenger cyclic adenosine monophosphate with subsequent rise in autonomous cardiomyocyte beating rate. Bioelectronic readouts are obtained through a multi-electrode array that measures real-time electrophysiological responses at 32 spatially-distinct locations. Irradiation at 27 µW mm-2 results in a 14% elevation of the beating rate within 20-25 min, which remains stable for at least 2 h. The beating rate can be cycled through "on" and "off" light states, and its magnitude is a monotonic function of irradiation intensity. The integrated platform can be extended to stretchable and flexible substrates, and can open new avenues in bioelectronic medicine, including closed-loop systems for cardiac regulation and intervention, for example, in the context of arrythmias.
71.
Spatial ciliary signaling regulates the dorsal/ventral regionalization of human brain organoids.
Abstract:
Regionalization of the brain is a fundamental question in human developmental biology. Primary cilia are known for a critical organelle for dorsal/ventral fate of brain formation in mice, but little is known about how signaling in the primary cilia regulate regionalization of the human brain. Here, we found that signaling in the primary cilia function in regionalization of the brain using brain organoids derived from human induced pluripotent stem (iPS) cells. Deletion of a ciliary GTPase, ARL13B, induced partially ventralized neural stem cells in the dorsal cortical organoids, despite using a guided dorsal cortical organoid differentiation protocol. Mechanistically, ARL13B knockout (KO) neural stem cells decreased ciliary localization of GPR161, a negative regulator of SHH signaling in primary cilia and increased SONIC HEDGEHOG (SHH) signaling. GPR161 deletion also induced ventralized neural stem cells in the dorsal cortical organoids, despite using the guided differentiation protocol. GPR161 deletion increased SHH signaling mediated by decreased GLI3 repressor formation. Pharmacological treatment to increase cAMP levels rescued GLI3 repressor formation and the differentiation of dorsal neural stem cells in GPR161 KO brain organoids. Importantly, elevating the amount of ciliary cAMP by optogenetics restored the generation of dorsal neural stem cells in GPR161 KO brain organoids. These data indicate that spatial ciliary signaling, the ARL13B-GPR161-cAMP axis in primary cilia, is a fundamental regulator of the dorsal/ventral regionalization of the human brain.
72.
Intracellular tau fragment droplets serve as seeds for tau fibrils.
Abstract:
Intracellular tau aggregation requires a local protein concentration increase, referred to as "droplets". However, the cellular mechanism for droplet formation is poorly understood. Here, we expressed OptoTau, a P301L mutant tau fused with CRY2olig, a light-sensitive protein that can form homo-oligomers. Under blue light exposure, OptoTau increased tau phosphorylation and was sequestered in aggresomes. Suppressing aggresome formation by nocodazole formed tau granular clusters in the cytoplasm. The granular clusters disappeared by discontinuing blue light exposure or 1,6-hexanediol treatment suggesting that intracellular tau droplet formation requires microtubule collapse. Expressing OptoTau-ΔN, a species of N-terminal cleaved tau observed in the Alzheimer's disease brain, formed 1,6-hexanediol and detergent-resistant tau clusters in the cytoplasm with blue light stimulation. These intracellular stable tau clusters acted as a seed for tau fibrils in vitro. These results suggest that tau droplet formation and N-terminal cleavage are necessary for neurofibrillary tangles formation in neurodegenerative diseases.
73.
TPM4 condensates glycolytic enzymes to fuel actin reorganization under hyperosmotic stress.
Abstract:
Actin homeostasis is fundamental for cell structure and consumes a large portion of cellular ATP. It has been documented in the literature that certain glycolytic enzymes can interact with actin, indicating an intricate interplay between the cytoskeleton and cellular metabolism. Here we report that hyperosmotic stress triggers actin severing and subsequent phase separation of the actin-binding protein TPM4. TPM4 condensates glycolytic enzymes such as HK2, PFKM, and PKM2, and adhere to and wrap around actin filaments. Notably, the condensates of TPM4 and glycolytic enzymes are enriched of NADH and ATP, suggestive of their functional importance in cell metabolism. At cellular level, actin filaments assembly is enhanced upon hyperosmotic stress and TPM4 condensation, while depletion of TPM4 impaired osmolarity-induced actin reorganization. At tissue level, co-localized condensates of TPM4 and glycolytic enzymes are observed in renal tissues subjected to hyperosmotic stress. Together, our findings suggest that stress-induced actin perturbation may act on TPM4 to organize glycolytic hubs that tether energy production to cytoskeletal reorganization.
74.
Multisite Assembly of Gateway Induced Clones (MAGIC): a flexible cloning toolbox with diverse applications in vertebrate model systems.
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Gillespie, W
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Zhang, Y
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Ruiz, OE
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Cerda III, J
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Ortiz-Guzman, J
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Turner, WD
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Largoza, G
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Sherman, M
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Mosser, LE
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Fujimoto, E
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Chien, CB
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Kwan, KM
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Arenkiel, BR
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Devine, WP
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Wythe, JD
Abstract:
Here we present the Multisite Assembly of Gateway Induced Clones (MAGIC) system, which harnesses site-specific recombination-based cloning via Gateway technology for rapid, modular assembly of between 1 and 3 “Entry” vector components, all into a fourth, standard high copy “Destination” plasmid backbone. The MAGIC toolkit spans a range of in vitro and in vivo uses, from directing tunable gene expression, to driving simultaneous expression of microRNAs and fluorescent reporters, to enabling site-specific recombinase-dependent gene expression. All MAGIC system components are directly compatible with existing multisite gateway Tol2 systems currently used in zebrafish, as well as existing eukaryotic cell culture expression Destination plasmids, and available mammalian lentiviral and adenoviral Destination vectors, allowing rapid cross-species experimentation. Moreover, herein we describe novel vectors with flanking piggyBac transposon elements for stable genomic integration in vitro or in vivo when used with piggyBac transposase. Collectively, the MAGIC system facilitates transgenesis in cultured mammalian cells, electroporated mouse and chick embryos, as well as in injected zebrafish embryos, enabling the rapid generation of innovative DNA constructs for biological research due to a shared, common plasmid platform.
75.
Self-powered triboelectric-responsive microneedles with controllable release of optogenetically engineered extracellular vesicles for intervertebral disc degeneration repair.
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Zhang, W
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Qin, X
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Li, G
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Zhou, X
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Li, H
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Wu, D
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Song, Y
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Zhao, K
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Wang, K
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Feng, X
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Tan, L
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Wang, B
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Sun, X
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Wen, Z
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Yang, C
Abstract:
Excessive exercise is an etiological factor of intervertebral disc degeneration (IVDD). Engineered extracellular vesicles (EVs) exhibit excellent therapeutic potential for disease-modifying treatments. Herein, we fabricate an exercise self-powered triboelectric-responsive microneedle (MN) assay with the sustainable release of optogenetically engineered EVs for IVDD repair. Mechanically, exercise promotes cytosolic DNA sensing-mediated inflammatory activation in senescent nucleus pulposus (NP) cells (the master cell population for IVD homeostasis maintenance), which accelerates IVDD. TREX1 serves as a crucial nuclease, and disassembly of TRAM1-TREX1 complex disrupts the subcellular localization of TREX1, triggering TREX1-dependent genomic DNA damage during NP cell senescence. Optogenetically engineered EVs deliver TRAM1 protein into senescent NP cells, which effectively reconstructs the elimination function of TREX1. Triboelectric nanogenerator (TENG) harvests mechanical energy and triggers the controllable release of engineered EVs. Notably, an optogenetically engineered EV-based targeting treatment strategy is used for the treatment of IVDD, showing promising clinical potential for the treatment of degeneration-associated disorders.