Qr: switch:"BphS"
Showing 1 - 25 of 63 results
1.
Optogenetic tools for optimizing key signalling nodes in synthetic biology.
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Tian, Y
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Xu, S
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Ye, Z
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Liu, H
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Wei, D
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Zabed, HM
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Yun, J
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Zhang, G
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Zhang, Y
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Zhang, C
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Liu, R
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Li, J
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Qi, X
Abstract:
The modification of key enzymes for chemical production plays a crucial role in enhancing the yield of targeted products. However, manipulating key nodes in specific signalling pathways remains constrained by traditional gene overexpression or knockout strategies. Discovering and designing optogenetic tools enable us to regulate enzymatic activity or gene expression at key nodes in a spatiotemporal manner, rather than relying solely on chemical induction throughout production processes. In this review, we discuss the recent applications of optogenetic tools in the regulation of microbial metabolites, plant sciences and disease therapies. We categorize optogenetic tools into five classes based on their distinct applications. First, light-induced gene expression schedules can balance the trade-off between chemical production and cell growth phases. Second, light-triggered liquid-liquid phase separation (LLPS) modules provide opportunities to co-localize and condense key enzymes for enhancing catalytic efficiency. Third, light-induced subcellular localized photoreceptors enable the relocation of protein of interest across various subcellular compartments, allowing for the investigation of their dynamic regulatory processes. Fourth, light-regulated enzymes can dynamically regulate production of cyclic nucleotides or investigate endogenous components similar with conditional depletion or recovery function of protein of interest. Fifth, light-gated ion channels and pumps can be utilized to investigate dynamic ion signalling cascades in both animals and plants, or to boost ATP accumulation for enhancing biomass or bioproduct yields in microorganisms. Overall, this review aims to provide a comprehensive overview of optogenetic strategies that have the potential to advance both basic research and bioindustry within the field of synthetic biology.
2.
Capitalizing on mechanistic insights to power design of future-ready intracellular optogenetics tools.
Abstract:
Intracellular optogenetics represents a rapidly advancing biotechnology that enables precise, reversible control of protein activity, signaling dynamics, and cellular behaviours using genetically encoded, light-responsive systems. Originally pioneered in neuroscience through channelrhodopsins to manipulate neuronal excitability, the field has since expanded into diverse intracellular applications with broad implications for medicine, agriculture, and biomanufacturing. Key to these advances are photoreceptors such as cryptochrome 2 (CRY2), light-oxygen-voltage (LOV) domains, and phytochromes, which undergo conformational changes upon illumination to trigger conditional protein-protein interactions, localization shifts, or phase transitions. Recent engineering breakthroughs-including the creation of red-light responsive systems such as MagRed that exploit endogenous biliverdin-have enhanced tissue penetration, minimized phototoxicity, and expanded applicability to complex biological systems. This review provides an overarching synthesis of the molecular principles underlying intracellular optogenetic actuators, including the photophysical basis of light-induced conformational changes, oligomerization, and signaling control. We highlight strategies that employ domain fusions, rational mutagenesis, and synthetic circuits to extend their utility across biological and industrial contexts. We also critically assess current limitations, such as chromophore dependence, light delivery challenges, and safety considerations, so as to frame realistic paths towards translation. Looking ahead, future opportunities include multi-colour and multiplexed systems, integration with high-throughput omics and artificial intelligence, and development of non-invasive modalities suited for in vivo and industrial applications. Intracellular optogenetics is thus emerging as a versatile platform technology, with the potential to reshape how we interrogate biology and engineer cells for therapeutic, agricultural, and environmental solutions.
3.
Optogenetic enzymes: A deep dive into design and impact.
Abstract:
Optogenetically regulated enzymes offer unprecedented spatiotemporal control over protein activity, intermolecular interactions, and intracellular signaling. Many design strategies have been developed for their fabrication based on the principles of intrinsic allostery, oligomerization or 'split' status, intracellular compartmentalization, and steric hindrance. In addition to employing photosensory domains as part of the traditional optogenetic toolset, the specificity of effector domains has also been leveraged for endogenous applications. Here, we discuss the dynamics of light activation while providing a bird's eye view of the crafting approaches, targets, and impact of optogenetic enzymes in orchestrating cellular functions, as well as the bottlenecks and an outlook into the future.
4.
Improving the Response of Microbial Fuel Cell-Based Biosensing through Optogenetic Enhancement of Electroactive Biofilms.
Abstract:
Early detection of pollutants in water discharge is an integral part of environmental monitoring. Electroactive biofilm (EAB)-enabled, microbial fuel cell (MFC)-based biosensors facilitate self-powered online pollutant detection. However, as EABs are highly dynamic, naturally formed EABs as sensing and transducing elements limit the performance of MFC-based biosensors. Here, we report a fast-response and sensitive MFC-based biosensor enabled by enhancing Shewanella oneidensis biofilms on the electrode using an optogenetic approach. We incorporated a near-infrared (NIR) light-responsive synthetic bis(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) module into S. oneidensis to promote biofilm formation on the anode under NIR light. The biosensors with enhanced EABs exhibited a rapid and sensitive response to Cr(VI), reducing the sensing time from approximately 30 min to just 3 min. This improved sensing performance was maintained over three sensing cycles, even with fluctuating Cr(VI) concentrations. Based on the analyses of the electrode biofilms and extracellular polymeric substance matrices, different Cr(VI) response mechanisms for the normal and enhanced EABs were proposed; enhanced EAB's massive dispersal by Cr(VI) was the cause of the improved response of the biosensors. Such improved response still held in the natural water matrix. This proof-of-concept study provides valuable insights into controlling electrode biofilm dynamics for the rapid and robust early detection of pollutants using MFC-based biosensors.
5.
Empowering bacteria with light: Optogenetically engineered bacteria for light-controlled disease theranostics and regulation.
Abstract:
Bacterial therapy has emerged as a promising approach for disease treatment due to its environmental sensitivity, immunogenicity, and modifiability. However, the clinical application of engineered bacteria is limited by differences of expression levels in patients and possible off-targeting. Optogenetics, which combines optics and genetics, offers key advantages such as remote controllability, non-invasiveness, and precise spatiotemporal control. By utilizing optogenetic tools, the behavior of engineered bacteria can be finely regulated, enabling on-demand control of the dosage and location of their therapeutic products. In this review, we highlight the latest advancements in the optogenetic engineering of bacteria for light-controlled disease theranostics and therapeutic regulation. By constructing a three-dimensional analytical framework of “sense-produce-apply”, we begin by discussing the key components of bacterial optogenetic systems, categorizing them based on their photosensitive protein response to blue, green, and red light. Next, we introduce innovative light-producing tools that extend beyond traditional light sources. Then, special emphasis is placed on the biomedical applications of optogenetically engineered bacteria in treating diseases such as cancer, intestinal inflammation and systemic disease regulation. Finally, we address the challenges and future prospects of bacterial optogenetics, outlining potential directions for enhancing the safety and efficacy of light-controlled bacterial therapies. This review aims to provide insights and strategies for researchers working to advance the application of optogenetically engineered bacteria in drug delivery, precision medicine and therapeutic regulation.
6.
Insight into Optogenetics for Diabetes Management.
Abstract:
Optogenetics is an interdisciplinary field wherein optical and genetic engineering methods are employed together to impart photounresponsive cells (usually of higher animals) the ability to respond to light through expression of light-sensitive proteins sourced generally from algae or bacteria. It enables precise spatiotemporal control of various cellular activities through light stimulation. Recently, emerging as a synthetic biology-based approach for diabetes management, optogenetics can provide user-control of hormonal secretion by photoactivation of a suitably modified cell. For around a decade, studies have been performed on the applicability of various light-sensitive proteins and their incorporation into pancreatic and nonpancreatic cells for photoinduced insulin secretion. Further, in vivo studies demonstrated amelioration of diabetes in mouse models through photoactivation of the implanted engineered cells. Here, we attempt to highlight the various optogenetic approaches explored in terms of influencing the insulin secretion pathway at different points in light of the natural insulin secretion pathway in pancreatic β cells. We also discuss how transgenic cells of both pancreatic as well as nonpancreatic origin are exploited for photoinduced secretion of insulin. Recent advances on integration of “smart” technologies for remote control of light irradiation and thereby insulin secretion from implanted engineered cells in preclinical models are also described. Additionally, the need for further comprehensive studies on irradiation parameters, red-shifted opsins, and host–cell interaction is stressed to realize the full potential of optogenetics as a clinically applicable modality providing user-controlled “on demand” hormonal secretion for better management of diabetes.
7.
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.
8.
Optogenetics in pancreatic islets: Actuators and effects.
Abstract:
The Islets of Langerhans reside within the endocrine pancreas as highly vascularised micro-organs that are responsible for the secretion of key hormones, such as insulin and glucagon. Islet function relies on a range of dynamic molecular processes that include calcium (Ca2+) waves, hormone pulses, and complex interactions between islet cell types. Dysfunction of these processes results in poor maintenance of blood glucose homeostasis and is a hallmark of diabetes. Very recently, the development of optogenetic methods that rely on light-sensitive molecular actuators has allowed perturbing islet function with near physiological spatio-temporal acuity. These actuators harness natural photoreceptor proteins and their engineered variants to manipulate mouse and human cells that are not normally light-responsive. Until recently, optogenetics in islet biology has primarily focused on hormone production and secretion; however, studies on further aspects of islet function, including paracrine regulation between islet cell types and dynamics within intracellular signaling pathways are emerging. Here, we discuss the applicability of optogenetics to islets cells and comprehensively review seminal as well as recent work on optogenetic actuators and their effects in islet function and diabetes mellitus (DM).
9.
Optogenetic therapeutic strategies for diabetes mellitus.
Abstract:
Diabetes mellitus (DM) is a common chronic disease affecting humans globally. It is characterized by abnormally elevated blood glucose levels due to the failure of insulin production or reduction of insulin sensitivity and functionality. Insulin and glucagon-like peptide (GLP)-1 replenishment or improvement of insulin resistance are the two major strategies to treat diabetes. Recently, optogenetics that uses genetically encoded light-sensitive proteins to precisely control cell functions has been regarded as a novel therapeutic strategy for diabetes. Here, we summarize the latest development of optogenetics and its integration with synthetic biology approaches to produce light-responsive cells for insulin/GLP-1 production, amelioration of insulin resistance and neuromodulation of insulin secretion. In addition, we introduce the development of cell encapsulation and delivery methods and smart bioelectronic devices for the in vivo application of optogenetics-based cell therapy in diabetes. The remaining challenges for optogenetics-based cell therapy in the clinical translational study are also discussed.
10.
Ultrafast Primary Dynamics and Isomerization Mechanism of a Far-Red Sensing Cyanobacteriochrome.
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Niu, K
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Wang, D
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Zhang, Y
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Biju, L
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Liu, N
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Wang, X
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Wang, L
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Ren, Z
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Lu, F
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Yang, X
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Zhong, D
Abstract:
Far-red cyanobacteriochromes (CBCRs) are bilin-based photosensory proteins that promise to be novel optical agents in optogenetics and deep tissue imaging. Recent structural studies of a far-red CBCR 2551g3 have revealed a unique all-Z,syn chromophore conformation in the far-red-absorbing Pfr state. Understanding the photoswitching mechanism through bilin photoisomerization is important for developing novel biomedical applications. Here, we employ femtosecond spectroscopy and site-directed mutagenesis to systematically characterize the dynamics of wild-type 2551g3 and four critical mutants in the 15Z Pfr state. We captured local relaxations in several picoseconds and isomerization dynamics in hundreds of picoseconds. Most mutants exhibited faster local relaxation, while their twisting dynamics and photoproducts depend on specific protein-chromophore interactions around the D-ring and C-ring. These results collectively reveal a unique dynamic pattern of excited-state evolution arising from a relatively rigid protein environment, thereby elucidating the molecular mechanism of Pfr-state photoisomerization in far-red CBCRs.
11.
Antidiabetic Close Loop Based on Wearable DNA-Hydrogel Glucometer and Implantable Optogenetic Cells.
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Man, T
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Yu, G
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Zhu, F
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Huang, Y
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Wang, Y
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Su, Y
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Deng, S
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Pei, H
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Li, L
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Ye, H
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Wan, Y
Abstract:
Diabetes mellitus and its associated secondary complications have become a pressing global healthcare issue. The current integrated theranostic plan involves a glucometer-tandem pump. However, external condition-responsive insulin delivery systems utilizing rigid glucose sensors pose challenges in on-demand, long-term insulin administration. To overcome these challenges, we present a novel model of antidiabetic management based on printable metallo-nucleotide hydrogels and optogenetic engineering. The conductive hydrogels were self-assembled by bioorthogonal chemistry using oligonucleotides, carbon nanotubes, and glucose oxidase, enabling continuous glucose monitoring in a broad range (0.5-40 mM). The optogenetically engineered cells were enabled glucose regulation in type I diabetic mice via a far-red light-induced transgenic expression of insulin with a month-long avidity. Combining with a microchip-integrated microneedle patch, a prototyped close-loop system was constructed. The glucose levels detected by the sensor were received and converted by a wireless controller to modulate far-infrared light, thereby achieving on-demand insulin expression for several weeks. This study sheds new light on developing next-generation diagnostic and therapy systems for personalized and digitalized precision medicine.
12.
Lighting the way: recent developments and applications in molecular optogenetics.
Abstract:
Molecular optogenetics utilizes genetically encoded, light-responsive protein switches to control the function of molecular processes. Over the last two years, there have been notable advances in the development of novel optogenetic switches, their utilization in elucidating intricate signaling pathways, and their progress toward practical applications in biotechnological processes, material sciences, and therapeutic applications. In this review, we discuss these areas, offer insights into recent developments, and contemplate future directions.
13.
Crucial Residue for Tuning Thermal Relaxation Kinetics in the Biliverdin-binding Cyanobacteriochrome Photoreceptor Revealed by Site-saturation Mutagenesis.
Abstract:
Cyanobacteriochromes (CBCRs) are cyanobacterial photoreceptors distantly related to the phytochromes sensing red and far-red light reversibly. Only the cGMP phosphodiesterase/Adenylate cyclase/FhlA (GAF) domain is needed for chromophore incorporation and proper photoconversion. The CBCR GAF domains covalently ligate linear tetrapyrrole chromophores and show reversible photoconversion between two light-absorbing states. In most cases, the two light-absorbing states are stable under dark conditions, but in some cases, the photoproduct state undergoes thermal relaxation back to the dark-adapted state during thermal relaxation. In this study, we examined the engineered CBCR GAF domain, AnPixJg2_BV4. AnPixJg2_BV4 covalently binds biliverdin IX-alpha (BV) and shows reversible photoconversion between a far-red-absorbing Pfr dark-adapted state and an orange-absorbing Po photoproduct state. Because the BV is an intrinsic chromophore of mammalian cells and absorbs far-red light penetrating into deep tissues, BV-binding CBCR molecules are useful for the development of optogenetic and bioimaging tools used in mammals. To obtain a better developmental platform molecule, we performed site-saturation random mutagenesis on the Phe319 position. We succeeded in obtaining variant molecules with higher chromophore-binding efficiency and higher molar extinction coefficient. Furthermore, we observed a wide variation in thermal relaxation kinetics, with an 81-fold difference between the slowest and fastest rates. Both molecules with relatively slow and fast thermal relaxation would be advantageous for optogenetic control.
14.
Unlocking the potential of optogenetics in microbial applications.
Abstract:
Optogenetics is a powerful approach that enables researchers to use light to dynamically manipulate cellular behavior. Since the first published use of optogenetics in synthetic biology, the field has expanded rapidly, yielding a vast array of tools and applications. Despite its immense potential for achieving high spatiotemporal precision, optogenetics has predominantly been employed as a substitute for conventional chemical inducers. In this short review, we discuss key features of microbial optogenetics and highlight applications for understanding biology, cocultures, bioproduction, biomaterials, and therapeutics, in which optogenetics is more fully utilized to realize goals not previously possible by other methods.
15.
A programmable protease-based protein secretion platform for therapeutic applications.
Abstract:
Cell-based therapies represent potent enabling technologies in biomedical science. However, current genetic control systems for engineered-cell therapies are predominantly based on the transcription or translation of therapeutic outputs. Here we report a protease-based rapid protein secretion system (PASS) that regulates the secretion of pretranslated proteins retained in the endoplasmic reticulum (ER) owing to an ER-retrieval signal. Upon cleavage by inducible proteases, these proteins are secreted. Three PASS variants (chemPASS, antigenPASS and optoPASS) are developed. With chemPASS, we demonstrate the reversal of hyperglycemia in diabetic mice within minutes via drug-induced insulin secretion. AntigenPASS-equipped cells recognize the tumor antigen and secrete granzyme B and perforin, inducing targeted cell apoptosis. Finally, results from mouse models of diabetes, hypertension and inflammatory pain demonstrate light-induced, optoPASS-mediated therapeutic peptide secretion within minutes, conferring anticipated therapeutic benefits. PASS is a flexible platform for rapid delivery of therapeutic proteins that can facilitate the development and adoption of cell-based precision therapies.
16.
Current Trends of Bacterial and Fungal Optoproteins for Novel Optical Applications.
Abstract:
Photoproteins, luminescent proteins or optoproteins are a kind of light-response protein responsible for the conversion of light into biochemical energy that is used by some bacteria or fungi to regulate specific biological processes. Within these specific proteins, there are groups such as the photoreceptors that respond to a given light wavelength and generate reactions susceptible to being used for the development of high-novel applications, such as the optocontrol of metabolic pathways. Photoswitchable proteins play important roles during the development of new materials due to their capacity to change their conformational structure by providing/eliminating a specific light stimulus. Additionally, there are bioluminescent proteins that produce light during a heatless chemical reaction and are useful to be employed as biomarkers in several fields such as imaging, cell biology, disease tracking and pollutant detection. The classification of these optoproteins from bacteria and fungi as photoreceptors or photoresponse elements according to the excitation-emission spectrum (UV-Vis-IR), as well as their potential use in novel applications, is addressed in this article by providing a structured scheme for this broad area of knowledge.
17.
Remotely Controllable Engineered Bacteria for Targeted Therapy of Pseudomonas aeruginosa Infection.
Abstract:
Pseudomonas aeruginosa (P. aeruginosa) infection has become an intractable problem worldwide due to the decreasing efficacy of the mainstay therapy, antibiotic treatment. Hence, exploring new drugs and therapies to address this issue is crucial. Here, we construct a chimeric pyocin (ChPy) to specifically kill P. aeruginosa and engineer a near-infrared (NIR) light-responsive strain to produce and deliver this drug. Our engineered bacterial strain can continuously produce ChPy in the absence of light and release it to kill P. aeruginosa via remotely and precisely controlled bacterial lysis induced by NIR light. We demonstrate that our engineered bacterial strain is effective in P. aeruginosa-infected wound therapy in the mouse model, as it eradicated PAO1 in mouse wounds and shortened the wound healing time. Our work presents a potentially spatiotemporal and noninvasively controlled therapeutic strategy of engineered bacteria for the targeted treatment of P. aeruginosa infections.
18.
The clinical potential of optogenetic interrogation of pathogenesis.
Abstract:
Opsin-based optogenetics has emerged as a powerful biomedical tool using light to control protein conformation. Such capacity has been initially demonstrated to control ion flow across the cell membrane, enabling precise control of action potential in excitable cells such as neurons or muscle cells. Further advancement in optogenetics incorporates a greater variety of photoactivatable proteins and results in flexible control of biological processes, such as gene expression and signal transduction, with commonly employed light sources such as LEDs or lasers in optical microscopy. Blessed by the precise genetic targeting specificity and superior spatiotemporal resolution, optogenetics offers new biological insights into physiological and pathological mechanisms underlying health and diseases. Recently, its clinical potential has started to be capitalized, particularly for blindness treatment, due to the convenient light delivery into the eye.
19.
Programming the lifestyles of engineered bacteria for cancer therapy.
Abstract:
Bacteria can be genetically engineered to act as therapeutic delivery vehicles in the treatment of tumors, killing cancer cells or activating the immune system. This is known as bacteria-mediated cancer therapy (BMCT). Tumor invasion, colonization and tumor regression are major biological events, which are directly associated with antitumor effects and are uncontrollable due to the influence of tumor microenvironments during the BMCT process. Here, we developed a genetic circuit for dynamically programming bacterial lifestyles (planktonic, biofilm or lysis), to precisely manipulate the process of bacterial adhesion, colonization and drug release in the BMCT process, via hierarchical modulation of the lighting power density of near-infrared (NIR) light. The deep tissue penetration of NIR offers us a modality for spatio-temporal and non-invasive control of bacterial genetic circuits in vivo. By combining computational modeling with a high-throughput characterization device, we optimized the genetic circuits in engineered bacteria to program the process of bacterial lifestyle transitions by altering the illumination scheme of NIR. Our results showed that programming intratumoral bacterial lifestyle transitions allows precise control of multiple key steps throughout the BMCT process and therapeutic efficacy can be greatly improved by controlling the localization and dosage of therapeutic agents via optimizing the illumination scheme.
20.
Measurement of Secreted Embryonic Alkaline Phosphatase.
Abstract:
Secreted reporters have been demonstrated to be simple and useful tools for analyzing transcriptional regulation in mammalian cells. The distinctive feature of these assays is the ability to detect reporter gene expression in the culture supernatant without affecting the cell physiology or leading to cell lysis, which allows repeated experimentation and sampling of the culture medium using the same cell cultures. Secreted embryonic alkaline phosphatase (SEAP) is one of the most widely used reporter, which can be easily detected using colorimetry following incubation with a substrate, such as p-nitrophenol phosphate. In this report, we present detailed procedures for detection and quantification of the SEAP reporter. We believe that this step-by-step protocol can be easily used by researchers to monitor and measure molecular genetic events in a variety of mammalian cells due to its simplicity and ease of handling. Graphical abstract Schematic overview of the workflow described in this protocol.
21.
Optogenetic-controlled immunotherapeutic designer cells for post-surgical cancer immunotherapy.
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Yu, Y
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Wu, X
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Wang, M
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Liu, W
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Zhang, L
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Zhang, Y
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Hu, Z
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Zhou, X
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Jiang, W
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Zou, Q
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Cai, F
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Ye, H
Abstract:
Surgical resection is the main treatment option for most solid tumors, yet cancer recurrence after surgical resection remains a significant challenge in cancer therapy. Recent advances in cancer immunotherapy are enabling radical cures for many tumor patients, but these technologies remain challenging to apply because of side effects related to uncontrollable immune system activation. Here, we develop far-red light-controlled immunomodulatory engineered cells (FLICs) that we load into a hydrogel scaffold, enabling the precise optogenetic control of cytokines release (IFN-β, TNF-α, and IL-12) upon illumination. Experiments with a B16F10 melanoma resection mouse model show that FLICs-loaded hydrogel implants placed at the surgical wound site achieve sustainable release of immunomodulatory cytokines, leading to prevention of tumor recurrence and increased animal survival. Moreover, the FLICs-loaded hydrogel implants elicit long-term immunological memory that prevents against tumor recurrence. Our findings illustrate that this optogenetic perioperative immunotherapy with FLICs-loaded hydrogel implants offers a safe treatment option for solid tumors based on activating host innate and adaptive immune systems to inhibit tumor recurrence after surgery. Beyond extending the optogenetics toolbox for immunotherapy, we envision that our optogenetic-controlled living cell factory platform could be deployed for other biomedical contexts requiring precision induction of bio-therapeutic dosage.
22.
Light-regulated gene expression in Bacteria: Fundamentals, advances, and perspectives.
Abstract:
Numerous photoreceptors and genetic circuits emerged over the past two decades and now enable the light-dependent i.e., optogenetic, regulation of gene expression in bacteria. Prompted by light cues in the near-ultraviolet to near-infrared region of the electromagnetic spectrum, gene expression can be up- or downregulated stringently, reversibly, non-invasively, and with precision in space and time. Here, we survey the underlying principles, available options, and prominent examples of optogenetically regulated gene expression in bacteria. While transcription initiation and elongation remain most important for optogenetic intervention, other processes e.g., translation and downstream events, were also rendered light-dependent. The optogenetic control of bacterial expression predominantly employs but three fundamental strategies: light-sensitive two-component systems, oligomerization reactions, and second-messenger signaling. Certain optogenetic circuits moved beyond the proof-of-principle and stood the test of practice. They enable unprecedented applications in three major areas. First, light-dependent expression underpins novel concepts and strategies for enhanced yields in microbial production processes. Second, light-responsive bacteria can be optogenetically stimulated while residing within the bodies of animals, thus prompting the secretion of compounds that grant health benefits to the animal host. Third, optogenetics allows the generation of precisely structured, novel biomaterials. These applications jointly testify to the maturity of the optogenetic approach and serve as blueprints bound to inspire and template innovative use cases of light-regulated gene expression in bacteria. Researchers pursuing these lines can choose from an ever-growing, versatile, and efficient toolkit of optogenetic circuits.
23.
An adaptive tracking illumination system for optogenetic control of single bacterial cells.
Abstract:
Single-cell behaviors are essential during early-stage biofilm formation. In this study, we aimed to evaluate whether single-cell behaviors could be precisely and continuously manipulated by optogenetics. We thus established adaptive tracking illumination (ATI), a novel illumination method to precisely manipulate the gene expression and bacterial behavior of Pseudomonas aeruginosa on the surface at the single-cell level by using the combination of a high-throughput bacterial tracking algorithm, optogenetic manipulation, and adaptive microscopy. ATI enables precise gene expression control by manipulating the optogenetic module gene expression and type IV pili (TFP)-mediated motility and microcolony formation during biofilm formation through bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) level modifications in single cells. Moreover, we showed that the spatial organization of single cells in mature biofilms could be controlled using ATI. Therefore, this novel method we established might markedly answer various questions or resolve problems in microbiology. KEY POINTS: • High-resolution spatial and continuous optogenetic control of individual bacteria. • Phenotype-specific optogenetic control of individual bacteria. • Capacity to control biologically relevant processes in engineered single cells.
24.
Optogenetics for transcriptional programming and genetic engineering.
Abstract:
Optogenetics combines genetics and biophotonics to enable noninvasive control of biological processes with high spatiotemporal precision. When engineered into protein machineries that govern the cellular information flow as depicted in the central dogma, multiple genetically encoded non-opsin photosensory modules have been harnessed to modulate gene transcription, DNA or RNA modifications, DNA recombination, and genome engineering by utilizing photons emitting in the wide range of 200-1000 nm. We present herein generally applicable modular strategies for optogenetic engineering and highlight latest advances in the broad applications of opsin-free optogenetics to program transcriptional outputs and precisely manipulate the mammalian genome, epigenome, and epitranscriptome. We also discuss current challenges and future trends in opsin-free optogenetics, which has been rapidly evolving to meet the growing needs in synthetic biology and genetics research.
25.
A Self-Powered Optogenetic System for Implantable Blood Glucose Control.
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Liu, Z
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Zhou, Y
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Qu, X
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Xu, L
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Zou, Y
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Shan, Y
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Shao, J
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Wang, C
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Liu, Y
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Xue, J
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Jiang, D
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Fan, Y
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Li, Z
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Ye, H
Abstract:
Diabetes treatment and rehabilitation are usually a lifetime process. Optogenetic engineered designer cell-therapy holds great promise in regulating blood glucose homeostasis. However, portable, sustainable, and long-term energy supplementation has previously presented a challenge for the use of optogenetic stimulation in vivo. Herein, we purpose a self-powered optogenetic system (SOS) for implantable blood glucose control. The SOS consists of a biocompatible far-red light (FRL) source, FRL-triggered transgene-expressing cells, a power management unit, and a flexible implantable piezoelectric nanogenerator (i-PENG) to supply long-term energy by converting biomechanical energy into electricity. Our results show that this system can harvest energy from body movement and power the FRL source, which then significantly enhanced production of a short variant of human glucagon-like peptide 1 (shGLP-1) in vitro and in vivo. Indeed, diabetic mice equipped with the SOS showed rapid restoration of blood glucose homeostasis, improved glucose, and insulin tolerance. Our results suggest that the SOS is sufficiently effective in self-powering the modulation of therapeutic outputs to control glucose homeostasis and, furthermore, present a new strategy for providing energy in optogenetic-based cell therapy.