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Gordon GR. Neurovascular coupling during hypercapnia in cerebral blood flow regulation. Nat Commun 2024; 15:7636. [PMID: 39223137 PMCID: PMC11368962 DOI: 10.1038/s41467-024-50165-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2024] [Accepted: 06/28/2024] [Indexed: 09/04/2024] Open
Affiliation(s)
- Grant R Gordon
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada.
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2
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Ma P, Sternson S, Chen Y. The promise and peril of comparing fluorescence lifetime in biology revealed by simulations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.20.572686. [PMID: 38187652 PMCID: PMC10769356 DOI: 10.1101/2023.12.20.572686] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Signaling dynamics are crucial in biological systems, and biosensor-based real-time imaging has revolutionized their analysis. Fluorescence lifetime imaging microscopy (FLIM) excels over the widely used fluorescence intensity imaging by allowing the measurement of absolute signal levels, independent of sensor concentration. This capability enables the comparison of signaling dynamics across different animals, body regions, and timeframes. However, FLIM's advantage can be compromised by factors like autofluorescence in biological experiments. To address this, we introduce FLiSimBA, a flexible computational framework for realistic F luorescence Li fetime Sim ulation for B iological A pplications. Through simulations, we analyze the signal-to-noise ratios of fluorescence lifetime data, determining measurement uncertainty and providing necessary error bars for lifetime measurements. Furthermore, we challenge the belief that fluorescence lifetime is unaffected by sensor expression and establish quantitative limits to this insensitivity in biological applications. Additionally, we propose innovations, notably multiplexed dynamic imaging that combines fluorescence intensity and lifetime measurements. This innovation can transform the number of signals that can be simultaneously monitored, thereby enabling a systems approach in studying signaling dynamics. Thus, by incorporating diverse factors into our simulation framework, we uncover surprises, identify limitations, and propose advancements for fluorescence lifetime imaging in biology. This quantitative framework supports rigorous experimental design, facilitates accurate data interpretation, and paves the way for technological advancements in fluorescence lifetime imaging.
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3
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Pedre B. A guide to genetically-encoded redox biosensors: State of the art and opportunities. Arch Biochem Biophys 2024; 758:110067. [PMID: 38908743 DOI: 10.1016/j.abb.2024.110067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Revised: 06/18/2024] [Accepted: 06/19/2024] [Indexed: 06/24/2024]
Abstract
Genetically-encoded redox biosensors have become invaluable tools for monitoring cellular redox processes with high spatiotemporal resolution, coupling the presence of the redox-active analyte with a change in fluorescence signal that can be easily recorded. This review summarizes the available fluorescence recording methods and presents an in-depth classification of the redox biosensors, organized by the analytes they respond to. In addition to the fluorescent protein-based architectures, this review also describes the recent advances on fluorescent, chemigenetic-based redox biosensors and other emerging chemigenetic strategies. This review examines how these biosensors are designed, the biosensors sensing mechanism, and their practical advantages and disadvantages.
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Affiliation(s)
- Brandán Pedre
- Biochemistry, Molecular and Structural Biology Unit, Department of Chemistry, KU Leuven, Belgium.
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4
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Roman B, Mastoor Y, Sun J, Villanueva HC, Hinojosa G, Springer D, Liu JC, Murphy E. MICU3 Regulates Mitochondrial Calcium and Cardiac Hypertrophy. Circ Res 2024; 135:26-40. [PMID: 38747181 PMCID: PMC11189743 DOI: 10.1161/circresaha.123.324026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 05/01/2024] [Indexed: 06/22/2024]
Abstract
BACKGROUND Calcium (Ca2+) uptake by mitochondria occurs via the mitochondrial Ca2+ uniporter. Mitochondrial Ca2+ uniporter exists as a complex, regulated by 3 MICU (mitochondrial Ca2+ uptake) proteins localized in the intermembrane space: MICU1, MICU2, and MICU3. Although MICU3 is present in the heart, its role is largely unknown. METHODS We used CRISPR-Cas9 to generate a mouse with global deletion of MICU3 and an adeno-associated virus (AAV9) to overexpress MICU3 in wild-type mice. We examined the role of MICU3 in regulating mitochondrial calcium ([Ca2+]m) in ex vivo hearts using an optical method following adrenergic stimulation in perfused hearts loaded with a Ca2+-sensitive fluorophore. Additionally, we studied how deletion and overexpression of MICU3, respectively, impact cardiac function in vivo by echocardiography and the molecular composition of the mitochondrial Ca2+ uniporter complex via Western blot, immunoprecipitation, and Blue native-PAGE analysis. Finally, we measured MICU3 expression in failing human hearts. RESULTS MICU3 knock out hearts and cardiomyocytes exhibited a significantly smaller increase in [Ca2+]m than wild-type hearts following acute isoproterenol infusion. In contrast, heart with overexpression of MICU3 exhibited an enhanced increase in [Ca2+]m compared with control hearts. Echocardiography analysis showed no significant difference in cardiac function in knock out MICU3 mice relative to wild-type mice at baseline. However, mice with overexpression of MICU3 exhibited significantly reduced ejection fraction and fractional shortening compared with control mice. We observed a significant increase in the ratio of heart weight to tibia length in hearts with overexpression of MICU3 compared with controls, consistent with hypertrophy. We also found a significant decrease in MICU3 protein and expression in failing human hearts. CONCLUSIONS Our results indicate that increased and decreased expression of MICU3 enhances and reduces, respectively, the uptake of [Ca2+]m in the heart. We conclude that MICU3 plays an important role in regulating [Ca2+]m physiologically, and overexpression of MICU3 is sufficient to induce cardiac hypertrophy, making MICU3 a possible therapeutic target.
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Affiliation(s)
- Barbara Roman
- Cardiac Physiology Lab NHLBI, NIH, Bethesda, Maryland
| | - Yusuf Mastoor
- Cardiac Physiology Lab NHLBI, NIH, Bethesda, Maryland
| | - Junhui Sun
- Cardiac Physiology Lab NHLBI, NIH, Bethesda, Maryland
| | - Hector Chapoy Villanueva
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN
| | | | | | - Julia C. Liu
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN
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5
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Lira RB, Dillingh LS, Schuringa JJ, Yahioglu G, Suhling K, Roos WH. Fluorescence lifetime imaging microscopy of flexible and rigid dyes probes the biophysical properties of synthetic and biological membranes. Biophys J 2024; 123:1592-1609. [PMID: 38702882 PMCID: PMC11214022 DOI: 10.1016/j.bpj.2024.04.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 03/22/2024] [Accepted: 04/30/2024] [Indexed: 05/06/2024] Open
Abstract
Sensing of the biophysical properties of membranes using molecular reporters has recently regained widespread attention. This was elicited by the development of new probes of exquisite optical properties and increased performance, combined with developments in fluorescence detection. Here, we report on fluorescence lifetime imaging of various rigid and flexible fluorescent dyes to probe the biophysical properties of synthetic and biological membranes at steady state as well as upon the action of external membrane-modifying agents. We tested the solvatochromic dyes Nile red and 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine-N-(7-nitro-2-1,3-benzoxadiazol-4-yl) (ammonium salt) (NBD), the viscosity sensor Bodipy C12, the flipper dye FliptR, as well as the dyes 3,3'-dioctadecyloxacarbocyanine perchlorate (DiO), Bodipy C16, lissamine-rhodamine, and Atto647, which are dyes with no previous reported environmental sensitivity. The performance of the fluorescent probes, many of which are commercially available, was benchmarked with well-known environmental reporters, with Nile red and Bodipy C12 being specific reporters of medium hydration and viscosity, respectively. We show that some widely used ordinary dyes with no previous report of sensing capabilities can exhibit competing performance compared to highly sensitive commercially available or custom-based solvatochromic dyes, molecular rotors, or flipper in a wide range of biophysics experiments. Compared to other methods, fluorescence lifetime imaging is a minimally invasive and nondestructive method with optical resolution. It enables biophysical mapping at steady state or assessment of the changes induced by membrane-active molecules at subcellular level in both synthetic and biological membranes when intensity measurements fail to do so. The results have important consequences for the specific choice of the sensor and take into consideration factors such as probe sensitivity, response to environmental changes, ease and speed of data analysis, and the probe's intracellular distribution, as well as potential side effects induced by labeling and imaging.
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Affiliation(s)
- Rafael B Lira
- Moleculaire Biofysica, Zernike Instituut, Rijksuniversiteit Groningen, Groningen, the Netherlands.
| | - Laura S Dillingh
- Moleculaire Biofysica, Zernike Instituut, Rijksuniversiteit Groningen, Groningen, the Netherlands; Department of Hematology, Universitair Medisch Centrum Groningen & Rijksuniversiteit Groningen, Groningen, the Netherlands
| | - Jan-Jacob Schuringa
- Department of Hematology, Universitair Medisch Centrum Groningen & Rijksuniversiteit Groningen, Groningen, the Netherlands
| | | | - Klaus Suhling
- Department of Physics, King's College London, Strand, London, UK.
| | - Wouter H Roos
- Moleculaire Biofysica, Zernike Instituut, Rijksuniversiteit Groningen, Groningen, the Netherlands
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6
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Hara Y, Ichiraku A, Matsuda T, Sakane A, Sasaki T, Nagai T, Horikawa K. High-affinity tuning of single fluorescent protein-type indicators by flexible linker length optimization in topology mutant. Commun Biol 2024; 7:705. [PMID: 38851844 PMCID: PMC11162441 DOI: 10.1038/s42003-024-06394-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 05/29/2024] [Indexed: 06/10/2024] Open
Abstract
Genetically encoded Ca2+ indicators (GECIs) are versatile for live imaging of cellular activities. Besides the brightness and dynamic range of signal change of GECIs, Ca2+ affinity is another critical parameter for successful Ca2+ imaging, as the concentration range of Ca2+ dynamics differs from low nanomolar to sub-millimolar depending on the celltype and organism. However, ultrahigh-affinity GECIs, particularly the single fluorescent protein (1FP)-type, are lacking. Here, we report a simple strategy that increases Ca2+ affinity through the linker length optimization in topology mutants of existing 1FP-type GECIs. The resulting ultrahigh-affinity GECIs, CaMPARI-nano, BGECO-nano, and RCaMP-nano (Kd = 17-25 nM), enable unique biological applications, including the detection of low nanomolar Ca2+ dynamics, highlighting active signaling cells, and multi-functional imaging with other second messengers. The linker length optimization in topology mutants could be applied to other 1FP-type indicators of glutamate and potassium, rendering it a widely applicable technique for modulating indicator affinity.
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Affiliation(s)
- Yusuke Hara
- Department of Optical Imaging, Advanced Research Promotion Center, Tokushima University, 3-18-15 Kuramoto, Tokushima, Tokushima, 770-8503, Japan
| | - Aya Ichiraku
- Department of Optical Imaging, Advanced Research Promotion Center, Tokushima University, 3-18-15 Kuramoto, Tokushima, Tokushima, 770-8503, Japan
| | - Tomoki Matsuda
- Department of Biomolecular Science and Engineering, SANKEN, Osaka University, Mihogaoka 8-1, Ibaraki, Osaka, 567-0047, Japan
| | - Ayuko Sakane
- Department of Biochemistry, Tokushima University Graduate School of Medicine, 3-18-15 Kuramoto, Tokushima, Tokushima, 770-8503, Japan
- Division of Interdisciplinary Researches for Medicine and Photonics, Institute of Post-LED Photonics (pLED), Tokushima University, 3-18-15 Kuramoto, Tokushima, Tokushima, 770-8503, Japan
| | - Takuya Sasaki
- Department of Biochemistry, Tokushima University Graduate School of Medicine, 3-18-15 Kuramoto, Tokushima, Tokushima, 770-8503, Japan
| | - Takeharu Nagai
- Department of Biomolecular Science and Engineering, SANKEN, Osaka University, Mihogaoka 8-1, Ibaraki, Osaka, 567-0047, Japan
- Institute for Open and Transdisciplinary Research Initiatives, Osaka University, Yamadaoka 2-1, Suita, Osaka, 565-0871, Japan
| | - Kazuki Horikawa
- Department of Optical Imaging, Advanced Research Promotion Center, Tokushima University, 3-18-15 Kuramoto, Tokushima, Tokushima, 770-8503, Japan.
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7
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Mastoor Y, Harata M, Silva K, Liu C, Combs CA, Roman B, Murphy E. Monitoring mitochondrial calcium in cardiomyocytes during coverslip hypoxia using a fluorescent lifetime indicator. JOURNAL OF MOLECULAR AND CELLULAR CARDIOLOGY PLUS 2024; 8:100074. [PMID: 38854449 PMCID: PMC11156168 DOI: 10.1016/j.jmccpl.2024.100074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
An increase in mitochondrial calcium via the mitochondrial calcium uniporter (MCU) has been implicated in initiating cell death in the heart during ischemia-reperfusion (I/R) injury. Measurement of calcium during I/R has been challenging due to the pH sensitivity of indicators coupled with the fall in pH during I/R. The development of a pH-insensitive indicator, mitochondrial localized Turquoise Calcium fluorescence Lifetime Sensor (mito-TqFLITS), allows for quantifying mitochondrial calcium during I/R via fluorescent lifetime imaging. Mitochondrial calcium was monitored using mito-TqFLITS, in neonatal mouse ventricular myocytes (NMVM) isolated from germline MCU-KO mice and MCUfl/fl treated with CRE-recombinase to acutely knockout MCU. To simulate ischemia, a coverslip was placed on a monolayer of NMVMs to prevent access to oxygen and nutrients. Reperfusion was induced by removing the coverslip. Mitochondrial calcium increases threefold during coverslip hypoxia in MCU-WT. There is a significant increase in mitochondrial calcium during coverslip hypoxia in germline MCU-KO, but it is significantly lower than in MCU-WT. We also found that compared to WT, acute MCU-KO resulted in no difference in mitochondrial calcium during coverslip hypoxia and reoxygenation. To determine the role of mitochondrial calcium uptake via MCU in initiating cell death, we used propidium iodide to measure cell death. We found a significant increase in cell death in both the germline MCU-KO and acute MCU-KO, but this was similar to their respective WTs. These data demonstrate the utility of mito-TqFLITS to monitor mitochondrial calcium during simulated I/R and further show that germline loss of MCU attenuates the rise in mitochondrial calcium during ischemia but does not reduce cell death.
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Affiliation(s)
- Yusuf Mastoor
- Laboratory of Cardiac Physiology, Cardiovascular Branch, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD 20892
- These authors contributed equally
| | - Mikako Harata
- Laboratory of Cardiac Physiology, Cardiovascular Branch, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD 20892
- These authors contributed equally
| | - Kavisha Silva
- Laboratory of Cardiac Physiology, Cardiovascular Branch, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD 20892
| | - Chengyu Liu
- Transgenic Core, National Heart, Lung, and Blood Institute, NIH, Bethesda 20892
| | - Christian A. Combs
- Light Microscopy Core, National Heart, Lung, and Blood Institute, NIH, Bethesda 20892
| | - Barbara Roman
- Laboratory of Cardiac Physiology, Cardiovascular Branch, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD 20892
| | - Elizabeth Murphy
- Laboratory of Cardiac Physiology, Cardiovascular Branch, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD 20892
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8
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Kapitany V, Fatima A, Zickus V, Whitelaw J, McGhee E, Insall R, Machesky L, Faccio D. Single-sample image-fusion upsampling of fluorescence lifetime images. SCIENCE ADVANCES 2024; 10:eadn0139. [PMID: 38781345 PMCID: PMC11114222 DOI: 10.1126/sciadv.adn0139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 04/17/2024] [Indexed: 05/25/2024]
Abstract
Fluorescence lifetime imaging microscopy (FLIM) provides detailed information about molecular interactions and biological processes. A major bottleneck for FLIM is image resolution at high acquisition speeds due to the engineering and signal-processing limitations of time-resolved imaging technology. Here, we present single-sample image-fusion upsampling, a data-fusion approach to computational FLIM super-resolution that combines measurements from a low-resolution time-resolved detector (that measures photon arrival time) and a high-resolution camera (that measures intensity only). To solve this otherwise ill-posed inverse retrieval problem, we introduce statistically informed priors that encode local and global correlations between the two "single-sample" measurements. This bypasses the risk of out-of-distribution hallucination as in traditional data-driven approaches and delivers enhanced images compared, for example, to standard bilinear interpolation. The general approach laid out by single-sample image-fusion upsampling can be applied to other image super-resolution problems where two different datasets are available.
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Affiliation(s)
- Valentin Kapitany
- School of Physics & Astronomy, University of Glasgow, Glasgow G12 8QQ, UK
| | - Areeba Fatima
- School of Physics & Astronomy, University of Glasgow, Glasgow G12 8QQ, UK
| | - Vytautas Zickus
- School of Physics & Astronomy, University of Glasgow, Glasgow G12 8QQ, UK
- Department of Laser Technologies, Center for Physical Sciences and Technology, LT-10257 Vilnius, Lithuania
| | | | - Ewan McGhee
- School of Physics & Astronomy, University of Glasgow, Glasgow G12 8QQ, UK
- Cancer Research UK, Beatson Institute, Glasgow, UK
| | | | | | - Daniele Faccio
- School of Physics & Astronomy, University of Glasgow, Glasgow G12 8QQ, UK
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9
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Deepa SS, Thadathil N, Corral J, Mohammed S, Pham S, Rose H, Kinter MT, Richardson A, Díaz-García CM. MLKL overexpression leads to Ca 2+ and metabolic dyshomeostasis in a neuronal cell model. Cell Calcium 2024; 119:102854. [PMID: 38430790 PMCID: PMC10990772 DOI: 10.1016/j.ceca.2024.102854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 01/25/2024] [Accepted: 02/05/2024] [Indexed: 03/05/2024]
Abstract
The necroptotic effector molecule MLKL accumulates in neurons over the lifespan of mice, and its downregulation has the potential to improve cognition through neuroinflammation, and changes in the abundance of synaptic proteins and enzymes in the central nervous system. Notwithstanding, direct evidence of cell-autonomous effects of MLKL expression on neuronal physiology and metabolism are lacking. Here, we tested whether the overexpression of MLKL in the absence of cell death in the neuronal cell line Neuro-2a recapitulates some of the hallmarks of aging at the cellular level. Using genetically-encoded fluorescent biosensors, we monitored the cytosolic and mitochondrial Ca2+ levels, along with the cytosolic concentrations of several metabolites involved in energy metabolism (lactate, glucose, ATP) and oxidative stress (oxidized/reduced glutathione). We found that MLKL overexpression marginally decreased cell viability, however, it led to reduced cytosolic and mitochondrial Ca2+ elevations in response to Ca2+ influx from the extracellular space. On the contrary, Ca2+ signals were elevated after mobilizing Ca2+ from the endoplasmic reticulum. Transient elevations in cytosolic Ca2+, mimicking neuronal stimulation, lead to higher lactate levels and lower glucose concentrations in Neuro-2a cells when overexpressing MLKL, which suggest enhanced neuronal glycolysis. Despite these alterations, energy levels and glutathione redox state in the cell bodies remained largely preserved after inducing MLKL overexpression for 24-48 h. Taken together, our proof-of-concept experiments are consistent with the hypothesis that MLKL overexpression in the absence of cell death contributes to both Ca2+ and metabolic dyshomeostasis, which are cellular hallmarks of brain aging.
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Affiliation(s)
- Sathyaseelan S Deepa
- Department of Biochemistry and Physiology, University of Oklahoma Health Sciences Center, OK, USA; Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, OK, USA; Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
| | - Nidheesh Thadathil
- Department of Biochemistry and Physiology, University of Oklahoma Health Sciences Center, OK, USA
| | - Jorge Corral
- Department of Biochemistry and Physiology, University of Oklahoma Health Sciences Center, OK, USA; Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, OK, USA
| | - Sabira Mohammed
- Department of Biochemistry and Physiology, University of Oklahoma Health Sciences Center, OK, USA; Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, OK, USA; Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Sophia Pham
- Department of Biochemistry and Physiology, University of Oklahoma Health Sciences Center, OK, USA; Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, OK, USA
| | - Hadyn Rose
- Department of Biochemistry and Physiology, University of Oklahoma Health Sciences Center, OK, USA; Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, OK, USA
| | - Michael T Kinter
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Arlan Richardson
- Department of Biochemistry and Physiology, University of Oklahoma Health Sciences Center, OK, USA; Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, OK, USA; Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Oklahoma City VA Medical Center, Oklahoma City, OK, USA
| | - Carlos Manlio Díaz-García
- Department of Biochemistry and Physiology, University of Oklahoma Health Sciences Center, OK, USA; Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, OK, USA; Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, OK, USA.
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10
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Parry HA, Willingham TB, Giordano KA, Kim Y, Qazi S, Knutson JR, Combs CA, Glancy B. Impact of capillary and sarcolemmal proximity on mitochondrial structure and energetic function in skeletal muscle. J Physiol 2024; 602:1967-1986. [PMID: 38564214 PMCID: PMC11068488 DOI: 10.1113/jp286246] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 03/08/2024] [Indexed: 04/04/2024] Open
Abstract
Mitochondria within skeletal muscle cells are located either between the muscle contractile apparatus (interfibrillar mitochondria, IFM) or beneath the cell membrane (subsarcolemmal mitochondria, SSM), with several structural and functional differences reported between IFM and SSM. However, recent 3D imaging studies demonstrate that mitochondria are particularly concentrated in the proximity of capillaries embedded in sarcolemmal grooves rather than in proximity to the sarcolemma itself (paravascular mitochondria, PVM). To evaluate the impact of capillary vs. sarcolemmal proximity, we compared the structure and function of skeletal muscle mitochondria located either lateral to embedded capillaries (PVM), adjacent to the sarcolemma but not in PVM pools (SSM) or interspersed between sarcomeres (IFM). Mitochondrial morphology and interactions were assessed by 3D electron microscopy coupled with machine learning segmentation, whereas mitochondrial energy conversion was assessed by two-photon microscopy of mitochondrial membrane potential, content, calcium, NADH redox and flux in live, intact cells. Structurally, although PVM and SSM were similarly larger than IFM, PVM were larger, rounder and had more physical connections to neighbouring mitochondria compared to both IFM and SSM. Functionally, PVM had similar or greater basal NADH flux compared to SSM and IFM, respectively, despite a more oxidized NADH pool and a greater membrane potential, signifying a greater activation of the electron transport chain in PVM. Together, these data indicate that proximity to capillaries has a greater impact on resting mitochondrial energy conversion and distribution in skeletal muscle than the sarcolemma alone. KEY POINTS: Capillaries have a greater impact on mitochondrial energy conversion in skeletal muscle than the sarcolemma. Paravascular mitochondria are larger, and the outer mitochondrial membrane is more connected with neighbouring mitochondria. Interfibrillar mitochondria are longer and have greater contact sites with other organelles (i.e. sarcoplasmic reticulum and lipid droplets). Paravascular mitochondria have greater activation of oxidative phosphorylation than interfibrillar mitochondria at rest, although this is not regulated by calcium.
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Affiliation(s)
- Hailey A. Parry
- National Lung, Blood, and Heart Institute, National Institutes of Health, Bethesda, MD, USA
| | - T. Bradley Willingham
- National Lung, Blood, and Heart Institute, National Institutes of Health, Bethesda, MD, USA
- Shephard Center’s Virginia C. Crawford Research Institute, Atlanta, GA, USA
| | | | - Yuho Kim
- National Lung, Blood, and Heart Institute, National Institutes of Health, Bethesda, MD, USA
- University of Massachusetts, Lowell, MA,USA
| | - Shureed Qazi
- National Lung, Blood, and Heart Institute, National Institutes of Health, Bethesda, MD, USA
| | - Jay R. Knutson
- National Lung, Blood, and Heart Institute, National Institutes of Health, Bethesda, MD, USA
| | - Christian A. Combs
- National Lung, Blood, and Heart Institute, National Institutes of Health, Bethesda, MD, USA
| | - Brian Glancy
- National Lung, Blood, and Heart Institute, National Institutes of Health, Bethesda, MD, USA
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
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11
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Jensen GC, Janis MK, Nguyen HN, David OW, Zastrow ML. Fluorescent Protein-Based Sensors for Detecting Essential Metal Ions across the Tree of Life. ACS Sens 2024; 9:1622-1643. [PMID: 38587931 PMCID: PMC11073808 DOI: 10.1021/acssensors.3c02695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/10/2024]
Abstract
Genetically encoded fluorescent metal ion sensors are powerful tools for elucidating metal dynamics in living systems. Over the last 25 years since the first examples of genetically encoded fluorescent protein-based calcium indicators, this toolbox of probes has expanded to include other essential and non-essential metal ions. Collectively, these tools have illuminated fundamental aspects of metal homeostasis and trafficking that are crucial to fields ranging from neurobiology to human nutrition. Despite these advances, much of the application of metal ion sensors remains limited to mammalian cells and tissues and a limited number of essential metals. Applications beyond mammalian systems and in vivo applications in living organisms have primarily used genetically encoded calcium ion sensors. The aim of this Perspective is to provide, with the support of historical and recent literature, an updated and critical view of the design and use of fluorescent protein-based sensors for detecting essential metal ions in various organisms. We highlight the historical progress and achievements with calcium sensors and discuss more recent advances and opportunities for the detection of other essential metal ions. We also discuss outstanding challenges in the field and directions for future studies, including detecting a wider variety of metal ions, developing and implementing a broader spectral range of sensors for multiplexing experiments, and applying sensors to a wider range of single- and multi-species biological systems.
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Affiliation(s)
- Gary C Jensen
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
| | - Makena K Janis
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
| | - Hazel N Nguyen
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
| | - Ogonna W David
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
| | - Melissa L Zastrow
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
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12
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Aggarwal A, Sunil S, Bendifallah I, Moon M, Drobizhev M, Zarowny L, Zheng J, Wu SY, Lohman AW, Tebo AG, Emiliani V, Podgorski K, Shen Y, Campbell RE. Blue-shifted genetically encoded Ca 2+ indicator with enhanced two-photon absorption. NEUROPHOTONICS 2024; 11:024207. [PMID: 38577628 PMCID: PMC10993905 DOI: 10.1117/1.nph.11.2.024207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 03/04/2024] [Accepted: 03/06/2024] [Indexed: 04/06/2024]
Abstract
Significance Genetically encoded calcium ion (Ca 2 + ) indicators (GECIs) are powerful tools for monitoring intracellular Ca 2 + concentration changes in living cells and model organisms. In particular, GECIs have found particular utility for monitoring the transient increase of Ca 2 + concentration that is associated with the neuronal action potential. However, the palette of highly optimized GECIs for imaging of neuronal activity remains relatively limited. Expanding the selection of available GECIs to include new colors and distinct photophysical properties could create new opportunities for in vitro and in vivo fluorescence imaging of neuronal activity. In particular, blue-shifted variants of GECIs are expected to have enhanced two-photon brightness, which would facilitate multiphoton microscopy. Aim We describe the development and applications of T-GECO1-a high-performance blue-shifted GECI based on the Clavularia sp.-derived mTFP1. Approach We use protein engineering and extensive directed evolution to develop T-GECO1. We characterize the purified protein and assess its performance in vitro using one-photon excitation in cultured rat hippocampal neurons, in vivo using one-photon excitation fiber photometry in mice, and ex vivo using two-photon Ca 2 + imaging in hippocampal slices. Results The Ca 2 + -bound state of T-GECO1 has an excitation peak maximum of 468 nm, an emission peak maximum of 500 nm, an extinction coefficient of 49,300 M - 1 cm - 1 , a quantum yield of 0.83, and two-photon brightness approximately double that of EGFP. The Ca 2 + -dependent fluorescence increase is 15-fold, and the apparent K d for Ca 2 + is 82 nM. With two-photon excitation conditions at 850 nm, T-GECO1 consistently enabled the detection of action potentials with higher signal-to-noise (SNR) than a late generation GCaMP variant. Conclusions T-GECO1 is a high-performance blue-shifted GECI that, under two-photon excitation conditions, provides advantages relative to late generation GCaMP variants.
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Affiliation(s)
- Abhi Aggarwal
- University of Alberta, Department of Chemistry, Edmonton, Alberta, Canada
- Allen Institute for Neural Dynamics, Seattle, Washington, United States
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, Virginia, United States
- University of Calgary, Hotchkiss Brain Institute, Department of Cell Biology and Anatomy Calgary, Alberta, Canada
| | - Smrithi Sunil
- Allen Institute for Neural Dynamics, Seattle, Washington, United States
| | | | - Michael Moon
- University of Alberta, Department of Chemistry, Edmonton, Alberta, Canada
| | - Mikhail Drobizhev
- Montana State University, Department of Microbiology and Cell Biology, Bozeman, Montana, United States
| | - Landon Zarowny
- University of Alberta, Department of Chemistry, Edmonton, Alberta, Canada
| | - Jihong Zheng
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, Virginia, United States
| | - Sheng-Yi Wu
- University of Alberta, Department of Chemistry, Edmonton, Alberta, Canada
| | - Alexander W. Lohman
- University of Calgary, Hotchkiss Brain Institute, Department of Cell Biology and Anatomy Calgary, Alberta, Canada
| | - Alison G. Tebo
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, Virginia, United States
| | | | - Kaspar Podgorski
- Allen Institute for Neural Dynamics, Seattle, Washington, United States
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, Virginia, United States
| | - Yi Shen
- University of Alberta, Department of Chemistry, Edmonton, Alberta, Canada
| | - Robert E. Campbell
- University of Alberta, Department of Chemistry, Edmonton, Alberta, Canada
- Université Laval, CERVO Brain Research Center, Department of Biochemistry, Microbiology, and Bioinformatics, Québec, Québec, Canada
- University of Tokyo, Department of Chemistry, Tokyo, Japan
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13
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Simpson EH, Akam T, Patriarchi T, Blanco-Pozo M, Burgeno LM, Mohebi A, Cragg SJ, Walton ME. Lights, fiber, action! A primer on in vivo fiber photometry. Neuron 2024; 112:718-739. [PMID: 38103545 PMCID: PMC10939905 DOI: 10.1016/j.neuron.2023.11.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 10/16/2023] [Accepted: 11/15/2023] [Indexed: 12/19/2023]
Abstract
Fiber photometry is a key technique for characterizing brain-behavior relationships in vivo. Initially, it was primarily used to report calcium dynamics as a proxy for neural activity via genetically encoded indicators. This generated new insights into brain functions including movement, memory, and motivation at the level of defined circuits and cell types. Recently, the opportunity for discovery with fiber photometry has exploded with the development of an extensive range of fluorescent sensors for biomolecules including neuromodulators and peptides that were previously inaccessible in vivo. This critical advance, combined with the new availability of affordable "plug-and-play" recording systems, has made monitoring molecules with high spatiotemporal precision during behavior highly accessible. However, while opening exciting new avenues for research, the rapid expansion in fiber photometry applications has occurred without coordination or consensus on best practices. Here, we provide a comprehensive guide to help end-users execute, analyze, and suitably interpret fiber photometry studies.
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Affiliation(s)
- Eleanor H Simpson
- Department of Psychiatry, Columbia University Medical Center, New York, NY, USA; New York State Psychiatric Institute, New York, NY, USA.
| | - Thomas Akam
- Department of Experimental Psychology, University of Oxford, Oxford, UK; Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, UK.
| | - Tommaso Patriarchi
- Institute of Pharmacology and Toxicology, University of Zürich, Zürich, Switzerland; Neuroscience Center Zürich, University and ETH Zürich, Zürich, Switzerland.
| | - Marta Blanco-Pozo
- Department of Experimental Psychology, University of Oxford, Oxford, UK; Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, UK
| | - Lauren M Burgeno
- Department of Experimental Psychology, University of Oxford, Oxford, UK; Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Ali Mohebi
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Stephanie J Cragg
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA
| | - Mark E Walton
- Department of Experimental Psychology, University of Oxford, Oxford, UK; Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, UK
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14
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Rohner VL, Lamothe-Molina PJ, Patriarchi T. Engineering, applications, and future perspectives of GPCR-based genetically encoded fluorescent indicators for neuromodulators. J Neurochem 2024; 168:163-184. [PMID: 38288673 DOI: 10.1111/jnc.16045] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 12/20/2023] [Accepted: 12/22/2023] [Indexed: 02/23/2024]
Abstract
This review explores the evolving landscape of G-protein-coupled receptor (GPCR)-based genetically encoded fluorescent indicators (GEFIs), with a focus on their development, structural components, engineering strategies, and applications. We highlight the unique features of this indicator class, emphasizing the importance of both the sensing domain (GPCR structure and activation mechanism) and the reporting domain (circularly permuted fluorescent protein (cpFP) structure and fluorescence modulation). Further, we discuss indicator engineering approaches, including the selection of suitable cpFPs and expression systems. Additionally, we showcase the diversity and flexibility of their application by presenting a summary of studies where such indicators were used. Along with all the advantages, we also focus on the current limitations as well as common misconceptions that arise when using these indicators. Finally, we discuss future directions in indicator engineering, including strategies for screening with increased throughput, optimization of the ligand-binding properties, structural insights, and spectral diversity.
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Affiliation(s)
- Valentin Lu Rohner
- Institute of Pharmacology and Toxicology, University of Zürich, Zürich, Switzerland
| | | | - Tommaso Patriarchi
- Institute of Pharmacology and Toxicology, University of Zürich, Zürich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
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15
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Ma P, Chen P, Tilden EI, Aggarwal S, Oldenborg A, Chen Y. Fast and slow: Recording neuromodulator dynamics across both transient and chronic time scales. SCIENCE ADVANCES 2024; 10:eadi0643. [PMID: 38381826 PMCID: PMC10881037 DOI: 10.1126/sciadv.adi0643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 01/17/2024] [Indexed: 02/23/2024]
Abstract
Neuromodulators transform animal behaviors. Recent research has demonstrated the importance of both sustained and transient change in neuromodulators, likely due to tonic and phasic neuromodulator release. However, no method could simultaneously record both types of dynamics. Fluorescence lifetime of optical reporters could offer a solution because it allows high temporal resolution and is impervious to sensor expression differences across chronic periods. Nevertheless, no fluorescence lifetime change across the entire classes of neuromodulator sensors was previously known. Unexpectedly, we find that several intensity-based neuromodulator sensors also exhibit fluorescence lifetime responses. Furthermore, we show that lifetime measures in vivo neuromodulator dynamics both with high temporal resolution and with consistency across animals and time. Thus, we report a method that can simultaneously measure neuromodulator change over transient and chronic time scales, promising to reveal the roles of multi-time scale neuromodulator dynamics in diseases, in response to therapies, and across development and aging.
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Affiliation(s)
- Pingchuan Ma
- Department of Neuroscience, Washington University, St. Louis, MO 63110, USA
- Ph.D. Program in Neuroscience, Washington University, St. Louis, MO 63110, USA
| | - Peter Chen
- Department of Neuroscience, Washington University, St. Louis, MO 63110, USA
- Master’s Program in Biomedical Engineering, Washington University, St. Louis, MO 63110, USA
| | - Elizabeth I. Tilden
- Department of Neuroscience, Washington University, St. Louis, MO 63110, USA
- Ph.D. Program in Neuroscience, Washington University, St. Louis, MO 63110, USA
| | - Samarth Aggarwal
- Department of Neuroscience, Washington University, St. Louis, MO 63110, USA
| | - Anna Oldenborg
- Department of Neuroscience, Washington University, St. Louis, MO 63110, USA
| | - Yao Chen
- Department of Neuroscience, Washington University, St. Louis, MO 63110, USA
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16
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Ma C, Mohr JM, Lauer G, Metternich JT, Neutsch K, Ziebarth T, Reiner A, Kruss S. Ratiometric Imaging of Catecholamine Neurotransmitters with Nanosensors. NANO LETTERS 2024; 24:2400-2407. [PMID: 38345220 DOI: 10.1021/acs.nanolett.3c05082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
Neurotransmitters are important signaling molecules in the brain and are relevant in many diseases. Measuring them with high spatial and temporal resolutions in biological systems is challenging. Here, we develop a ratiometric fluorescent sensor/probe for catecholamine neurotransmitters on the basis of near-infrared (NIR) semiconducting single wall carbon nanotubes (SWCNTs). Phenylboronic acid (PBA)-based quantum defects are incorporated into them to interact selectively with catechol moieties. These PBA-SWCNTs are further modified with poly(ethylene glycol) phospholipids (PEG-PL) for biocompatibility. Catecholamines, including dopamine, do not affect the intrinsic E11 fluorescence (990 nm) of these (PEG-PL-PBA-SWCNT) sensors. In contrast, the defect-related E11* emission (1130 nm) decreases by up to 35%. Furthermore, this dual functionalization allows tuning selectivity by changing the charge of the PEG polymer. These sensors are not taken up by cells, which is beneficial for extracellular imaging, and they are functional in brain slices. In summary, we use dual functionalization of SWCNTs to create a ratiometric biosensor for dopamine.
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Affiliation(s)
- Chen Ma
- Department of Chemistry, Ruhr University Bochum, Bochum, North Rhine-Westphalia 44801, Germany
| | - Jennifer Maria Mohr
- Department of Chemistry, Ruhr University Bochum, Bochum, North Rhine-Westphalia 44801, Germany
| | - German Lauer
- Department of Biology and Biotechnology, Ruhr University Bochum, Bochum, North Rhine-Westphalia 44801, Germany
| | - Justus Tom Metternich
- Department of Chemistry, Ruhr University Bochum, Bochum, North Rhine-Westphalia 44801, Germany
- Fraunhofer Institute for Microelectronic Circuits and Systems, Duisburg, North Rhine-Westphalia 47057, Germany
| | - Krisztian Neutsch
- Department of Chemistry, Ruhr University Bochum, Bochum, North Rhine-Westphalia 44801, Germany
| | - Tim Ziebarth
- Department of Biology and Biotechnology, Ruhr University Bochum, Bochum, North Rhine-Westphalia 44801, Germany
| | - Andreas Reiner
- Department of Biology and Biotechnology, Ruhr University Bochum, Bochum, North Rhine-Westphalia 44801, Germany
| | - Sebastian Kruss
- Department of Chemistry, Ruhr University Bochum, Bochum, North Rhine-Westphalia 44801, Germany
- Fraunhofer Institute for Microelectronic Circuits and Systems, Duisburg, North Rhine-Westphalia 47057, Germany
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17
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Sekhon H, Ha JH, Presti MF, Procopio SB, Jarvis AR, Mirsky PO, John AM, Loh SN. Adaptable, turn-on maturation (ATOM) fluorescent biosensors for multiplexed detection in cells. Nat Methods 2023; 20:1920-1929. [PMID: 37945909 PMCID: PMC11080272 DOI: 10.1038/s41592-023-02065-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 10/04/2023] [Indexed: 11/12/2023]
Abstract
A grand challenge in biosensor design is to develop a single-molecule, fluorescent protein-based platform that can be easily adapted to recognize targets of choice. Here, we created a family of adaptable, turn-on maturation (ATOM) biosensors consisting of a monobody (circularly permuted at one of two positions) or a nanobody (circularly permuted at one of three positions) inserted into a fluorescent protein at one of three surface loops. Multiplexed imaging of live human cells coexpressing cyan, yellow and red ATOM sensors detected biosensor targets that were specifically localized to various subcellular compartments. Fluorescence activation involved ligand-dependent chromophore maturation with turn-on ratios of up to 62-fold in cells and 100-fold in vitro. Endoplasmic reticulum- and mitochondria-localized ATOM sensors detected ligands that were targeted to those organelles. The ATOM design was validated with three monobodies and one nanobody inserted into distinct fluorescent proteins, suggesting that customized ATOM sensors can be generated quickly.
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Affiliation(s)
- Harsimranjit Sekhon
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Jeung-Hoi Ha
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Maria F Presti
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Spencer B Procopio
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Ava R Jarvis
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Paige O Mirsky
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Anna M John
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Stewart N Loh
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA.
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18
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Ghafouri E, Bigdeli M, Khalafiyan A, Amirkhani Z, Ghanbari R, Hasan A, Khanahmad H, Boshtam M, Makvandi P. Unmasking the complex roles of hypocalcemia in cancer, COVID-19, and sepsis: Engineered nanodelivery and diagnosis. ENVIRONMENTAL RESEARCH 2023; 238:116979. [PMID: 37660871 DOI: 10.1016/j.envres.2023.116979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 08/20/2023] [Accepted: 08/23/2023] [Indexed: 09/05/2023]
Abstract
Calcium (Ca2+) homeostasis is essential for maintaining physiological processes in the body. Disruptions in Ca2+ signaling can lead to various pathological conditions including inflammation, fibrosis, impaired immune function, and accelerated senescence. Hypocalcemia, a common symptom in diseases such as acute respiratory distress syndrome (ARDS), cancer, septic shock, and COVID-19, can have both potential protective and detrimental effects. This article explores the multifaceted role of Ca2+ dysregulation in inflammation, fibrosis, impaired immune function, and accelerated senescence, contributing to disease severity. Targeting Ca2+ signaling pathways may provide opportunities to develop novel therapeutics for age-related diseases and combat viral infections. However, the role of Ca2+ in viral infections is complex, and evidence suggests that hypocalcemia may have a protective effect against certain viruses, while changes in Ca2+ homeostasis can influence susceptibility to viral infections. The effectiveness and safety of Ca2+ supplements in COVID-19 patients remain a subject of ongoing research and debate. Further investigations are needed to understand the intricate interplay between Ca2+ signaling and disease pathogenesis.
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Affiliation(s)
- Elham Ghafouri
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | | | - Anis Khalafiyan
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Zohre Amirkhani
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Roham Ghanbari
- School of Chemistry, College of Science, University of Tehran, Tehran, Iran
| | - Anwarul Hasan
- Department of Mechanical and Industrial Engineering, Qatar University, Doha 2713, Qatar; Biomedical Research Center, Qatar University, Doha 2713, Qatar
| | - Hossein Khanahmad
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
| | - Maryam Boshtam
- Isfahan Cardiovascular Research Center, Cardiovascular Research Institute, Isfahan University of Medical Sciences, Isfahan, Iran.
| | - Pooyan Makvandi
- The Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou People's Hospital, Quzhou, 324000, Zhejiang, China; School of Engineering, Institute for Bioengineering, The University of Edinburgh, Edinburgh, EH9 3JL, UK.
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19
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Vu CQ, Arai S. Quantitative Imaging of Genetically Encoded Fluorescence Lifetime Biosensors. BIOSENSORS 2023; 13:939. [PMID: 37887132 PMCID: PMC10605767 DOI: 10.3390/bios13100939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 10/16/2023] [Accepted: 10/17/2023] [Indexed: 10/28/2023]
Abstract
Genetically encoded fluorescence lifetime biosensors have emerged as powerful tools for quantitative imaging, enabling precise measurement of cellular metabolites, molecular interactions, and dynamic cellular processes. This review provides an overview of the principles, applications, and advancements in quantitative imaging with genetically encoded fluorescence lifetime biosensors using fluorescence lifetime imaging microscopy (go-FLIM). We highlighted the distinct advantages of fluorescence lifetime-based measurements, including independence from expression levels, excitation power, and focus drift, resulting in robust and reliable measurements compared to intensity-based approaches. Specifically, we focus on two types of go-FLIM, namely Förster resonance energy transfer (FRET)-FLIM and single-fluorescent protein (FP)-based FLIM biosensors, and discuss their unique characteristics and benefits. This review serves as a valuable resource for researchers interested in leveraging fluorescence lifetime imaging to study molecular interactions and cellular metabolism with high precision and accuracy.
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Affiliation(s)
- Cong Quang Vu
- WPI Nano Life Science Institute, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Satoshi Arai
- WPI Nano Life Science Institute, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
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20
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Aggarwal A, Sunil S, Bendifallah I, Moon M, Drobizhev M, Zarowny L, Zheng J, Wu SY, Lohman AW, Tebo AG, Emiliani V, Podgorski K, Shen Y, Campbell RE. A blue-shifted genetically encoded Ca 2+ indicator with enhanced two-photon absorption. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.12.562058. [PMID: 37905143 PMCID: PMC10614751 DOI: 10.1101/2023.10.12.562058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Significance Genetically encoded calcium ion (Ca2+) indicators (GECIs) are powerful tools for monitoring intracellular Ca2+ concentration changes in living cells and model organisms. In particular, GECIs have found particular utility for monitoring the transient increase of Ca2+ concentration that is associated with the neuronal action potential. However, the palette of highly optimized GECIs for imaging of neuronal activity remains relatively limited. Expanding the selection of available GECIs to include new colors and distinct photophysical properties could create new opportunities for in vitro and in vivo fluorescence imaging of neuronal activity. In particular, blue-shifted variants of GECIs are expected to have enhanced two-photon brightness, which would facilitate multiphoton microscopy. Aim We describe the development and applications of T-GECO1 - a high-performance blue-shifted GECI based on the Clavularia sp.-derived mTFP1. Approach We used protein engineering and extensive directed evolution to develop T-GECO1. We characterize the purified protein and assess its performance in vitro using one-photon excitation in cultured rat hippocampal neurons, in vivo using one-photon excitation fiber photometry in mice, and ex vivo using two-photon Ca2+ imaging in hippocampal slices. Results The Ca2+-bound state of T-GECO1 has an excitation peak maximum of 468 nm, an emission peak maximum of 500 nm, an extinction coefficient of 49,300 M-1cm-1, a quantum yield of 0.83, and two-photon brightness approximately double that of EGFP. The Ca2+-dependent fluorescence increase is 15-fold and the apparent Kd for Ca2+ is 82 nM. With two-photon excitation conditions at 850 nm, T-GECO1 consistently enabled detection of action potentials with higher signal-to-noise (SNR) than a late generation GCaMP variant. Conclusion T-GECO1 is a high performance blue-shifted GECI that, under two-photon excitation conditions, provides advantages relative to late generation GCaMP variants.
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Affiliation(s)
- Abhi Aggarwal
- University of Alberta, Department of Chemistry, Edmonton, Alberta, Canada
- Allen Institute for Neural Dynamics, Seattle, Washington, United States of America
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, Virginia, United States of America
- University of Calgary, Department of Cell Biology and Anatomy and Hotchkiss Brain Institute, Calgary, Alberta, Canada
| | - Smrithi Sunil
- Allen Institute for Neural Dynamics, Seattle, Washington, United States of America
| | | | - Michael Moon
- University of Alberta, Department of Chemistry, Edmonton, Alberta, Canada
| | - Mikhail Drobizhev
- Montana State University, Department of Microbiology and Cell Biology, Bozeman, Montana, United States of America
| | - Landon Zarowny
- University of Alberta, Department of Chemistry, Edmonton, Alberta, Canada
| | - Jihong Zheng
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, Virginia, United States of America
| | - Sheng-Yi Wu
- University of Alberta, Department of Chemistry, Edmonton, Alberta, Canada
| | - Alexander W. Lohman
- University of Calgary, Department of Cell Biology and Anatomy and Hotchkiss Brain Institute, Calgary, Alberta, Canada
| | - Alison G. Tebo
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, Virginia, United States of America
| | | | - Kaspar Podgorski
- Allen Institute for Neural Dynamics, Seattle, Washington, United States of America
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, Virginia, United States of America
| | - Yi Shen
- University of Alberta, Department of Chemistry, Edmonton, Alberta, Canada
| | - Robert E. Campbell
- University of Alberta, Department of Chemistry, Edmonton, Alberta, Canada
- Université Laval, CERVO Brain Research Center and Department of Biochemistry, Microbiology, and Bioinformatics, Québec, Québec, Canada
- The University of Tokyo, Department of Chemistry, Bunkyo-ku, Tokyo, Japan
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21
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Mo Y, Zhou H, Xu J, Chen X, Li L, Zhang S. Genetically encoded fluorescence lifetime biosensors: overview, advances, and opportunities. Analyst 2023; 148:4939-4953. [PMID: 37721109 DOI: 10.1039/d3an01201h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/19/2023]
Abstract
Genetically encoded biosensors based on fluorescent proteins (FPs) are powerful tools for tracking analytes and cellular events with high spatial and temporal resolution in living cells and organisms. Compared with intensiometric readout and ratiometric readout, fluorescence lifetime readout provides absolute measurements, independent of the biosensor expression level and instruments. Thus, genetically encoded fluorescence lifetime biosensors play a vital role in facilitating accurate quantitative assessments within intricate biological systems. In this review, we first provide a concise description of the categorization and working mechanism of genetically encoded fluorescence lifetime biosensors. Subsequently, we elaborate on the combination of the fluorescence lifetime imaging technique and lifetime analysis methods with fluorescence lifetime biosensors, followed by their application in monitoring the dynamics of environment parameters, analytes and cellular events. Finally, we discuss worthwhile considerations for the design, optimization and development of fluorescence lifetime-based biosensors from three representative cases.
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Affiliation(s)
- Yidan Mo
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No. 500, Dongchuan Rd, Shanghai 200241, China
| | - Huangmei Zhou
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No. 500, Dongchuan Rd, Shanghai 200241, China
| | - Jinming Xu
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No. 500, Dongchuan Rd, Shanghai 200241, China
| | - Xihang Chen
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No. 500, Dongchuan Rd, Shanghai 200241, China
| | - Lei Li
- School of Science, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu, 214122, China.
| | - Sanjun Zhang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No. 500, Dongchuan Rd, Shanghai 200241, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
- NYU-ECNU Institute of Physics at NYU Shanghai, No. 3663, North Zhongshan Rd, Shanghai 200062, China.
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22
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Xu S, Momin M, Ahmed S, Hossain A, Veeramuthu L, Pandiyan A, Kuo CC, Zhou T. Illuminating the Brain: Advances and Perspectives in Optoelectronics for Neural Activity Monitoring and Modulation. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2303267. [PMID: 37726261 DOI: 10.1002/adma.202303267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 05/30/2023] [Indexed: 09/21/2023]
Abstract
Optogenetic modulation of brain neural activity that combines optical and electrical modes in a unitary neural system has recently gained robust momentum. Controlling illumination spatial coverage, designing light-activated modulators, and developing wireless light delivery and data transmission are crucial for maximizing the use of optical neuromodulation. To this end, biocompatible electrodes with enhanced optoelectrical performance, device integration for multiplexed addressing, wireless transmission, and multimodal operation in soft systems have been developed. This review provides an outlook for uniformly illuminating large brain areas while spatiotemporally imaging the neural responses upon optoelectrical stimulation with little artifacts. Representative concepts and important breakthroughs, such as head-mounted illumination, multiple implanted optical fibers, and micro-light-delivery devices, are discussed. Examples of techniques that incorporate electrophysiological monitoring and optoelectrical stimulation are presented. Challenges and perspectives are posed for further research efforts toward high-density optoelectrical neural interface modulation, with the potential for nonpharmacological neurological disease treatments and wireless optoelectrical stimulation.
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Affiliation(s)
- Shumao Xu
- Department of Engineering Science and Mechanics, Center for Neural Engineering, The Pennsylvania State University, Pennsylvania, 16802, USA
| | - Marzia Momin
- Department of Engineering Science and Mechanics, Center for Neural Engineering, The Pennsylvania State University, Pennsylvania, 16802, USA
| | - Salahuddin Ahmed
- Department of Engineering Science and Mechanics, Center for Neural Engineering, The Pennsylvania State University, Pennsylvania, 16802, USA
| | - Arafat Hossain
- Department of Electrical Engineering, The Pennsylvania State University, Pennsylvania, 16802, USA
| | - Loganathan Veeramuthu
- Department of Molecular Science and Engineering, National Taipei University of Technology, Taipei, 10608, Republic of China
| | - Archana Pandiyan
- Department of Molecular Science and Engineering, National Taipei University of Technology, Taipei, 10608, Republic of China
| | - Chi-Ching Kuo
- Department of Molecular Science and Engineering, National Taipei University of Technology, Taipei, 10608, Republic of China
| | - Tao Zhou
- Department of Engineering Science and Mechanics, Center for Neural Engineering, The Pennsylvania State University, Pennsylvania, 16802, USA
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23
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Barroso M, Monaghan MG, Niesner R, Dmitriev RI. Probing organoid metabolism using fluorescence lifetime imaging microscopy (FLIM): The next frontier of drug discovery and disease understanding. Adv Drug Deliv Rev 2023; 201:115081. [PMID: 37647987 PMCID: PMC10543546 DOI: 10.1016/j.addr.2023.115081] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 04/20/2023] [Accepted: 08/24/2023] [Indexed: 09/01/2023]
Abstract
Organoid models have been used to address important questions in developmental and cancer biology, tissue repair, advanced modelling of disease and therapies, among other bioengineering applications. Such 3D microenvironmental models can investigate the regulation of cell metabolism, and provide key insights into the mechanisms at the basis of cell growth, differentiation, communication, interactions with the environment and cell death. Their accessibility and complexity, based on 3D spatial and temporal heterogeneity, make organoids suitable for the application of novel, dynamic imaging microscopy methods, such as fluorescence lifetime imaging microscopy (FLIM) and related decay time-assessing readouts. Several biomarkers and assays have been proposed to study cell metabolism by FLIM in various organoid models. Herein, we present an expert-opinion discussion on the principles of FLIM and PLIM, instrumentation and data collection and analysis protocols, and general and emerging biosensor-based approaches, to highlight the pioneering work being performed in this field.
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Affiliation(s)
- Margarida Barroso
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY 12208, USA
| | - Michael G Monaghan
- Department of Mechanical, Manufacturing and Biomedical Engineering, Trinity College Dublin, Dublin 02, Ireland
| | - Raluca Niesner
- Dynamic and Functional In Vivo Imaging, Freie Universität Berlin and Biophysical Analytics, German Rheumatism Research Center, Berlin, Germany
| | - Ruslan I Dmitriev
- Tissue Engineering and Biomaterials Group, Department of Human Structure and Repair, Faculty of Medicine and Health Sciences, Ghent University, C. Heymanslaan 10, 9000 Ghent, Belgium; Ghent Light Microscopy Core, Ghent University, 9000 Ghent, Belgium.
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24
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Hellweg L, Edenhofer A, Barck L, Huppertz MC, Frei MS, Tarnawski M, Bergner A, Koch B, Johnsson K, Hiblot J. A general method for the development of multicolor biosensors with large dynamic ranges. Nat Chem Biol 2023; 19:1147-1157. [PMID: 37291200 PMCID: PMC10449634 DOI: 10.1038/s41589-023-01350-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 04/25/2023] [Indexed: 06/10/2023]
Abstract
Fluorescent biosensors enable the study of cell physiology with spatiotemporal resolution; yet, most biosensors suffer from relatively low dynamic ranges. Here, we introduce a family of designed Förster resonance energy transfer (FRET) pairs with near-quantitative FRET efficiencies based on the reversible interaction of fluorescent proteins with a fluorescently labeled HaloTag. These FRET pairs enabled the straightforward design of biosensors for calcium, ATP and NAD+ with unprecedented dynamic ranges. The color of each of these biosensors can be readily tuned by changing either the fluorescent protein or the synthetic fluorophore, which enables simultaneous monitoring of free NAD+ in different subcellular compartments following genotoxic stress. Minimal modifications of these biosensors furthermore allow their readout to be switched to fluorescence intensity, fluorescence lifetime or bioluminescence. These FRET pairs thus establish a new concept for the development of highly sensitive and tunable biosensors.
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Affiliation(s)
- Lars Hellweg
- Department of Chemical Biology, Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Anna Edenhofer
- Department of Chemical Biology, Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Lucas Barck
- Department of Chemical Biology, Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Magnus-Carsten Huppertz
- Department of Chemical Biology, Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Michelle S Frei
- Department of Chemical Biology, Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Miroslaw Tarnawski
- Protein Expression and Characterization Facility, Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Andrea Bergner
- Department of Chemical Biology, Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Birgit Koch
- Department of Chemical Biology, Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Kai Johnsson
- Department of Chemical Biology, Max Planck Institute for Medical Research, Heidelberg, Germany
- Institute of Chemical Sciences and Engineering (ISIC), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Julien Hiblot
- Department of Chemical Biology, Max Planck Institute for Medical Research, Heidelberg, Germany.
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25
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Farrants H, Shuai Y, Lemon WC, Hernandez CM, Yang S, Patel R, Qiao G, Frei MS, Grimm JB, Hanson TL, Tomaska F, Turner GC, Stringer C, Keller PJ, Beyene AG, Chen Y, Liang Y, Lavis LD, Schreiter ER. A modular chemigenetic calcium indicator enables in vivo functional imaging with near-infrared light. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.18.549527. [PMID: 37503182 PMCID: PMC10370049 DOI: 10.1101/2023.07.18.549527] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Genetically encoded fluorescent calcium indicators have revolutionized neuroscience and other biological fields by allowing cellular-resolution recording of physiology during behavior. However, we currently lack bright, genetically targetable indicators in the near infrared that can be used in animals. Here, we describe WHaloCaMP, a modular chemigenetic calcium indicator built from bright dye-ligands and protein sensor domains that can be genetically targeted to specific cell populations. Fluorescence change in WHaloCaMP results from reversible quenching of the bound dye via a strategically placed tryptophan. WHaloCaMP is compatible with rhodamine dye-ligands that fluoresce from green to near-infrared, including several dye-ligands that efficiently label the central nervous system in animals. When bound to a near-infrared dye-ligand, WHaloCaMP1a is more than twice as bright as jGCaMP8s, and shows a 7× increase in fluorescence intensity and a 2.1 ns increase in fluorescence lifetime upon calcium binding. We use WHaloCaMP1a with near-infrared fluorescence emission to image Ca2+ responses in flies and mice, to perform three-color multiplexed functional imaging of hundreds of neurons and astrocytes in zebrafish larvae, and to quantitate calcium concentration using fluorescence lifetime imaging microscopy (FLIM).
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Affiliation(s)
- Helen Farrants
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Yichun Shuai
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - William C Lemon
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | | | - Shang Yang
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Ronak Patel
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Guanda Qiao
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Michelle S Frei
- Department of Chemical Biology, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
| | - Jonathan B Grimm
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Timothy L Hanson
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Filip Tomaska
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Glenn C Turner
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Carsen Stringer
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Philipp J Keller
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Abraham G Beyene
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Yao Chen
- Department of Neuroscience, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Yajie Liang
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Luke D Lavis
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Eric R Schreiter
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
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26
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Zheng Y, Li Y. Past, present, and future of tools for dopamine detection. Neuroscience 2023:S0306-4522(23)00295-6. [PMID: 37419404 DOI: 10.1016/j.neuroscience.2023.06.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 06/26/2023] [Accepted: 06/29/2023] [Indexed: 07/09/2023]
Abstract
Dopamine (DA) is a critical neuromodulator involved in various brain functions. To understand how DA regulates neural circuits and behaviors in the physiological and pathological conditions, it is essential to have tools that enable the direct detection of DA dynamics in vivo. Recently, genetically encoded DA sensors based on G protein-coupled receptors revolutionized this field, as it allows us to track in vivo DA dynamic with unprecedented spatial-temporal resolution, high molecular specificity, and sub-second kinetics. In this review, we first summarize traditional DA detection methods. Then we focus on the development of genetically encoded DA sensors and feature its significance to understanding dopaminergic neuromodulation across diverse behaviors and species. Finally, we present our perspectives about the future direction of the next-generation DA sensors and extend their potential applications. Overall, this review offers a comprehensive perspective on the past, present, and future of DA detection tools, with important implications for the study of DA functions in health and disease.
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Affiliation(s)
- Yu Zheng
- Peking-Tsinghua Center for Life Sciences, 100871 Beijing, China
| | - Yulong Li
- Peking-Tsinghua Center for Life Sciences, 100871 Beijing, China; State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, 100871 Beijing, China; PKU-IDG/McGovern Institute for Brain Research, 100871 Beijing, China; National Biomedical Imaging Center, Peking University, 100871 Beijing, China.
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27
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Bowman AJ, Huang C, Schnitzer MJ, Kasevich MA. Wide-field fluorescence lifetime imaging of neuron spiking and subthreshold activity in vivo. Science 2023; 380:1270-1275. [PMID: 37347862 PMCID: PMC10361454 DOI: 10.1126/science.adf9725] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 05/16/2023] [Indexed: 06/24/2023]
Abstract
The development of voltage-sensitive fluorescent probes suggests fluorescence lifetime as a promising readout for electrical activity in biological systems. Existing approaches fail to achieve the speed and sensitivity required for voltage imaging in neuroscience applications. We demonstrated that wide-field electro-optic fluorescence lifetime imaging microscopy (EO-FLIM) allows lifetime imaging at kilohertz frame-acquisition rates, spatially resolving action potential propagation and subthreshold neural activity in live adult Drosophila. Lifetime resolutions of <5 picoseconds at 1 kilohertz were achieved for single-cell voltage recordings. Lifetime readout is limited by photon shot noise, and the method provides strong rejection of motion artifacts and technical noise sources. Recordings revealed local transmembrane depolarizations, two types of spikes with distinct fluorescence lifetimes, and phase locking of spikes to an external mechanical stimulus.
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Affiliation(s)
- Adam J. Bowman
- Physics Department, Stanford University; 382 Via Pueblo Mall, Stanford, California 94305, USA
| | - Cheng Huang
- James H. Clark Center, Stanford University; 318 Campus Dr., Stanford, CA 94305, USA
- Present Address: Department of Neuroscience, Washington University School of Medicine St. Louis, MO 63110, USA
| | - Mark J. Schnitzer
- James H. Clark Center, Stanford University; 318 Campus Dr., Stanford, CA 94305, USA
- CNC Program, Stanford University; Stanford, CA, USA
- Howard Hughes Medical Institute, Stanford University; Stanford, CA, USA
| | - Mark A. Kasevich
- Physics Department, Stanford University; 382 Via Pueblo Mall, Stanford, California 94305, USA
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28
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Olsen RH, English JG. Advancements in G protein-coupled receptor biosensors to study GPCR-G protein coupling. Br J Pharmacol 2023; 180:1433-1443. [PMID: 36166832 PMCID: PMC10511148 DOI: 10.1111/bph.15962] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 09/12/2022] [Accepted: 09/15/2022] [Indexed: 11/28/2022] Open
Abstract
Enzymatic and cellular signalling biosensors are used to decipher the activities of complex biological systems. Biosensors for monitoring G protein-coupled receptors (GPCRs), the most drugged class of proteins in the human body, are plentiful and vary in utility, form and function. Their applications have continually expanded our understanding of this important protein class. Here, we briefly summarize a subset of this field with accelerating importance: transducer biosensors measuring receptor-coupling and selectivity, with an emphasis on sensors measuring receptor association and activation of heterotrimeric signalling complexes.
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Affiliation(s)
| | - Justin G. English
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84132 USA
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29
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Aggarwal A, Liu R, Chen Y, Ralowicz AJ, Bergerson SJ, Tomaska F, Mohar B, Hanson TL, Hasseman JP, Reep D, Tsegaye G, Yao P, Ji X, Kloos M, Walpita D, Patel R, Mohr MA, Tillberg PW, Looger LL, Marvin JS, Hoppa MB, Konnerth A, Kleinfeld D, Schreiter ER, Podgorski K. Glutamate indicators with improved activation kinetics and localization for imaging synaptic transmission. Nat Methods 2023; 20:925-934. [PMID: 37142767 PMCID: PMC10250197 DOI: 10.1038/s41592-023-01863-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Accepted: 03/21/2023] [Indexed: 05/06/2023]
Abstract
The fluorescent glutamate indicator iGluSnFR enables imaging of neurotransmission with genetic and molecular specificity. However, existing iGluSnFR variants exhibit low in vivo signal-to-noise ratios, saturating activation kinetics and exclusion from postsynaptic densities. Using a multiassay screen in bacteria, soluble protein and cultured neurons, we generated variants with improved signal-to-noise ratios and kinetics. We developed surface display constructs that improve iGluSnFR's nanoscopic localization to postsynapses. The resulting indicator iGluSnFR3 exhibits rapid nonsaturating activation kinetics and reports synaptic glutamate release with decreased saturation and increased specificity versus extrasynaptic signals in cultured neurons. Simultaneous imaging and electrophysiology at individual boutons in mouse visual cortex showed that iGluSnFR3 transients report single action potentials with high specificity. In vibrissal sensory cortex layer 4, we used iGluSnFR3 to characterize distinct patterns of touch-evoked feedforward input from thalamocortical boutons and both feedforward and recurrent input onto L4 cortical neuron dendritic spines.
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Affiliation(s)
- Abhi Aggarwal
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
- Allen Institute for Neural Dynamics, Seattle, WA, USA
| | - Rui Liu
- Department of Physics, University of California, San Diego, La Jolla, CA, USA
| | - Yang Chen
- Institute of Neuroscience and Cluster for Systems Neurology (SyNergy), Technical University of Munich (TUM), Munich, Germany
| | - Amelia J Ralowicz
- Department of Biological Sciences, Dartmouth College, Hanover, NH, USA
| | | | - Filip Tomaska
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
- Department of Physiology, Second Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Boaz Mohar
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Timothy L Hanson
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Jeremy P Hasseman
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Daniel Reep
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Getahun Tsegaye
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Pantong Yao
- Neurosciences Graduate Program, University of California San Diego, La Jolla, CA, USA
| | - Xiang Ji
- Department of Physics, University of California, San Diego, La Jolla, CA, USA
| | - Marinus Kloos
- Institute of Neuroscience and Cluster for Systems Neurology (SyNergy), Technical University of Munich (TUM), Munich, Germany
| | - Deepika Walpita
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Ronak Patel
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Manuel A Mohr
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
- Department of Biosystems Science and Engineering, Swiss Federal Institute of Technology (ETH) Zurich, Basel, Switzerland
| | - Paul W Tillberg
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Loren L Looger
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
- Howard Hughes Medical Institute, Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA
| | - Jonathan S Marvin
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Michael B Hoppa
- Department of Biological Sciences, Dartmouth College, Hanover, NH, USA
| | - Arthur Konnerth
- Institute of Neuroscience and Cluster for Systems Neurology (SyNergy), Technical University of Munich (TUM), Munich, Germany
| | - David Kleinfeld
- Department of Physics, University of California, San Diego, La Jolla, CA, USA
- Section of Neurobiology, University of California, San Diego, La Jolla, CA, USA
| | - Eric R Schreiter
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Kaspar Podgorski
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA.
- Allen Institute for Neural Dynamics, Seattle, WA, USA.
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30
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Mahlandt EK, Kreider-Letterman G, Chertkova AO, Garcia-Mata R, Goedhart J. Cell-based optimization and characterization of genetically encoded location-based biosensors for Cdc42 or Rac activity. J Cell Sci 2023; 136:jcs260802. [PMID: 37226883 PMCID: PMC10234108 DOI: 10.1242/jcs.260802] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 04/13/2023] [Indexed: 05/26/2023] Open
Abstract
Rac (herein referring to the Rac family) and Cdc42 are Rho GTPases that regulate the formation of lamellipoda and filopodia, and are therefore crucial in processes such as cell migration. Relocation-based biosensors for Rac and Cdc42 have not been characterized well in terms of their specificity or affinity. In this study, we identify relocation sensor candidates for both Rac and Cdc42. We compared their (1) ability to bind the constitutively active Rho GTPases, (2) specificity for Rac and Cdc42, and (3) relocation efficiency in cell-based assays. Subsequently, the relocation efficiency was improved by a multi-domain approach. For Rac1, we found a sensor candidate with low relocation efficiency. For Cdc42, we found several sensors with sufficient relocation efficiency and specificity. These optimized sensors enable the wider application of Rho GTPase relocation sensors, which was showcased by the detection of local endogenous Cdc42 activity at assembling invadopodia. Moreover, we tested several fluorescent proteins and HaloTag for their influence on the recruitment efficiency of the Rho location sensor, to find optimal conditions for a multiplexing experiment. This characterization and optimization of relocation sensors will broaden their application and acceptance.
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Affiliation(s)
- Eike K. Mahlandt
- Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | | | - Anna O. Chertkova
- Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Rafael Garcia-Mata
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606, USA
| | - Joachim Goedhart
- Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
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31
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Sekhon H, Ha JH, Presti MF, Procopio SB, Mirsky PO, John AM, Loh SN. Adaptable, Turn-On Monobody (ATOM) Fluorescent Biosensors for Multiplexed Detection in Cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.28.534597. [PMID: 37034669 PMCID: PMC10081266 DOI: 10.1101/2023.03.28.534597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
A grand challenge in biosensor design is to develop a single molecule, fluorescent protein-based platform that can be easily adapted to recognize targets of choice. Conceptually, this can be achieved by fusing a small, antibody-like binding domain to a fluorescent protein in such a way that target binding activates fluorescence. Although this design is simple to envision, its execution is not obvious. Here, we created a family of adaptable, turn-on monobody (ATOM) biosensors consisting of a monobody, circularly permuted at one of two positions, inserted into a fluorescent protein at one of three surface loops. Multiplexed imaging of live human cells co-expressing cyan, yellow, and red ATOM sensors detected the biosensor targets (WDR5, SH2, and hRAS proteins) that were localized to the nucleus, cytoplasm, and plasma membrane, respectively, with high specificity. ER- and mitochondria-localized ATOM sensors also detected ligands that were targeted to those organelles. Fluorescence activation involved ligand-dependent chromophore maturation with fluorescence turn-on ratios of >20-fold in cells and up to 100-fold in vitro . The sensing mechanism was validated with three arbitrarily chosen monobodies inserted into jellyfish as well as anemone lineages of fluorescent proteins, suggesting that ATOM sensors with different binding specificities and additional colors can be generated relatively quickly.
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32
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Van Thillo T, Van Deuren V, Dedecker P. Smart genetically-encoded biosensors for the chemical monitoring of living systems. Chem Commun (Camb) 2023; 59:520-534. [PMID: 36519509 DOI: 10.1039/d2cc05363b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Genetically-encoded biosensors provide the all-optical and non-invasive visualization of dynamic biochemical events within living systems, which has allowed the discovery of profound new insights. Twenty-five years of biosensor development has steadily improved their performance and has provided us with an ever increasing biosensor repertoire. In this feature article, we present recent advances made in biosensor development and provide a perspective on the future direction of the field.
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Affiliation(s)
- Toon Van Thillo
- Department of Chemistry, KU Leuven, Celestijnenlaan 200G, 3001 Leuven, Belgium.
| | - Vincent Van Deuren
- Department of Chemistry, KU Leuven, Celestijnenlaan 200G, 3001 Leuven, Belgium.
| | - Peter Dedecker
- Department of Chemistry, KU Leuven, Celestijnenlaan 200G, 3001 Leuven, Belgium.
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33
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Mamontova AV, Simonyan TR, Bogdanov AM. Prospects of Genetically Encoded Flim Indicators for the Quantitative Assessment of Intracellular Parameters. Mol Biol 2022. [DOI: 10.1134/s0026893322050090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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34
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Vecchia MD, Conte-Daban A, Cappe B, Vandenberg W, Vandenabeele P, Riquet FB, Dedecker P. Spectrally Tunable Förster Resonance Energy Transfer-Based Biosensors Using Organic Dye Grafting. ACS Sens 2022; 7:2920-2927. [PMID: 36162130 DOI: 10.1021/acssensors.2c00066] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Biosensors based on Förster resonance energy transfer (FRET) have revolutionized cellular biology by allowing the direct measurement of biochemical processes in situ. Many genetically encoded sensors make use of fluorescent proteins that are limited in spectral versatility and that allow few ways to change the spectral properties once the construct has been created. In this work, we developed genetically encoded FRET biosensors based on the chemigenetic SNAP and HaloTag domains combined with matching organic fluorophores. We found that the resulting constructs can display comparable responses, kinetics, and reversibility compared to their fluorescent protein-based ancestors, but with the added advantage of spectral versatility, including the availability of red-shifted dye pairs. However, we also find that the introduction of these tags can alter the sensor readout, showing that careful validation is required before applying such constructs in practice. Overall, our approach delivers an innovative methodology that can readily expand the spectral variety and versatility of FRET-based biosensors.
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Affiliation(s)
- Marco Dalla Vecchia
- Lab for NanoBiology, Department of Chemistry, 3001 Leuven, Belgium.,Molecular Signaling and Cell Death Unit, Department of Biomedical Molecular Biology, Ghent University, 9052 Ghent, Belgium.,Cell Death and Inflammation Unit, VIB-UGent Center for Inflammation Research (IRC), Technologiepark 71, Zwijnaarde, 9052 Ghent, Belgium
| | | | - Benjamin Cappe
- Molecular Signaling and Cell Death Unit, Department of Biomedical Molecular Biology, Ghent University, 9052 Ghent, Belgium.,Cell Death and Inflammation Unit, VIB-UGent Center for Inflammation Research (IRC), Technologiepark 71, Zwijnaarde, 9052 Ghent, Belgium
| | - Wim Vandenberg
- Lab for NanoBiology, Department of Chemistry, 3001 Leuven, Belgium
| | - Peter Vandenabeele
- Molecular Signaling and Cell Death Unit, Department of Biomedical Molecular Biology, Ghent University, 9052 Ghent, Belgium.,Cell Death and Inflammation Unit, VIB-UGent Center for Inflammation Research (IRC), Technologiepark 71, Zwijnaarde, 9052 Ghent, Belgium
| | - Franck B Riquet
- Molecular Signaling and Cell Death Unit, Department of Biomedical Molecular Biology, Ghent University, 9052 Ghent, Belgium.,Cell Death and Inflammation Unit, VIB-UGent Center for Inflammation Research (IRC), Technologiepark 71, Zwijnaarde, 9052 Ghent, Belgium.,Université de Lille, CNRS, UMR 8523-PhLAM-Physique des Lasers Atomes et Molécules, 59000 Lille, France
| | - Peter Dedecker
- Lab for NanoBiology, Department of Chemistry, 3001 Leuven, Belgium
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35
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Mou L, Mandal K, Mecwan MM, Hernandez AL, Maity S, Sharma S, Herculano RD, Kawakita S, Jucaud V, Dokmeci MR, Khademhosseini A. Integrated biosensors for monitoring microphysiological systems. LAB ON A CHIP 2022; 22:3801-3816. [PMID: 36074812 PMCID: PMC9635816 DOI: 10.1039/d2lc00262k] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Microphysiological systems (MPSs), also known as organ-on-a-chip models, aim to recapitulate the functional components of human tissues or organs in vitro. Over the last decade, with the advances in biomaterials, 3D bioprinting, and microfluidics, numerous MPSs have emerged with applications to study diseased and healthy tissue models. Various organs have been modeled using MPS technology, such as the heart, liver, lung, and blood-brain barrier. An important aspect of in vitro modeling is the accurate phenotypical and functional characterization of the modeled organ. However, most conventional characterization methods are invasive and destructive and do not allow continuous monitoring of the cells in culture. On the other hand, microfluidic biosensors enable in-line, real-time sensing of target molecules with an excellent limit of detection and in a non-invasive manner, thereby effectively overcoming the limitation of the traditional techniques. Consequently, microfluidic biosensors have been increasingly integrated into MPSs and used for in-line target detection. This review discusses the state-of-the-art microfluidic biosensors by providing specific examples, detailing their main advantages in monitoring MPSs, and highlighting current developments in this field. Finally, we describe the remaining challenges and potential future developments to advance the current state-of-the-art in integrated microfluidic biosensors.
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Affiliation(s)
- Lei Mou
- Terasaki Institute for Biomedical Innovation, 1018 Westwood Blvd, Los Angeles, California, USA.
- Department of Clinical Laboratory, Third Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, No. 63 Duobao Road, Liwan District, Guangzhou, Guangdong, P. R. China
| | - Kalpana Mandal
- Terasaki Institute for Biomedical Innovation, 1018 Westwood Blvd, Los Angeles, California, USA.
| | - Marvin Magan Mecwan
- Terasaki Institute for Biomedical Innovation, 1018 Westwood Blvd, Los Angeles, California, USA.
| | - Ana Lopez Hernandez
- Terasaki Institute for Biomedical Innovation, 1018 Westwood Blvd, Los Angeles, California, USA.
| | - Surjendu Maity
- Terasaki Institute for Biomedical Innovation, 1018 Westwood Blvd, Los Angeles, California, USA.
| | - Saurabh Sharma
- Terasaki Institute for Biomedical Innovation, 1018 Westwood Blvd, Los Angeles, California, USA.
| | - Rondinelli Donizetti Herculano
- Terasaki Institute for Biomedical Innovation, 1018 Westwood Blvd, Los Angeles, California, USA.
- Department of Bioprocess and Biotechnology Engineering, School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara, SP 14801-902, Brazil
| | - Satoru Kawakita
- Terasaki Institute for Biomedical Innovation, 1018 Westwood Blvd, Los Angeles, California, USA.
| | - Vadim Jucaud
- Terasaki Institute for Biomedical Innovation, 1018 Westwood Blvd, Los Angeles, California, USA.
| | - Mehmet Remzi Dokmeci
- Terasaki Institute for Biomedical Innovation, 1018 Westwood Blvd, Los Angeles, California, USA.
| | - Ali Khademhosseini
- Terasaki Institute for Biomedical Innovation, 1018 Westwood Blvd, Los Angeles, California, USA.
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Kempmann A, Gensch T, Offenhäusser A, Tihaa I, Maybeck V, Balfanz S, Baumann A. The Functional Characterization of GCaMP3.0 Variants Specifically Targeted to Subcellular Domains. Int J Mol Sci 2022; 23:ijms23126593. [PMID: 35743038 PMCID: PMC9223625 DOI: 10.3390/ijms23126593] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 05/31/2022] [Accepted: 06/06/2022] [Indexed: 11/16/2022] Open
Abstract
Calcium (Ca2+) ions play a pivotal role in physiology and cellular signaling. The intracellular Ca2+ concentration ([Ca2+]i) is about three orders of magnitude lower than the extracellular concentration, resulting in a steep transmembrane concentration gradient. Thus, the spatial and the temporal dynamics of [Ca2+]i are ideally suited to modulate Ca2+-mediated cellular responses to external signals. A variety of highly sophisticated methods have been developed to gain insight into cellular Ca2+ dynamics. In addition to electrophysiological measurements and the application of synthetic dyes that change their fluorescent properties upon interaction with Ca2+, the introduction and the ongoing development of genetically encoded Ca2+ indicators (GECI) opened a new era to study Ca2+-driven processes in living cells and organisms. Here, we have focused on one well-established GECI, i.e., GCaMP3.0. We have systematically modified the protein with sequence motifs, allowing localization of the sensor in the nucleus, in the mitochondrial matrix, at the mitochondrial outer membrane, and at the plasma membrane. The individual variants and a cytosolic version of GCaMP3.0 were overexpressed and purified from E. coli cells to study their biophysical properties in solution. All versions were examined to monitor Ca2+ signaling in stably transfected cell lines and in primary cortical neurons transduced with recombinant Adeno-associated viruses (rAAV). In this comparative study, we provide evidence for a robust approach to reliably trace Ca2+ signals at the (sub)-cellular level with pronounced temporal resolution.
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Affiliation(s)
- Annika Kempmann
- Institute of Biological Information Processing, IBI-1, Research Center Jülich, 52428 Jülich, Germany; (A.K.); (T.G.); (S.B.)
| | - Thomas Gensch
- Institute of Biological Information Processing, IBI-1, Research Center Jülich, 52428 Jülich, Germany; (A.K.); (T.G.); (S.B.)
| | - Andreas Offenhäusser
- Institute of Biological Information Processing, IBI-3, Research Center Jülich, 52428 Jülich, Germany; (A.O.); (I.T.); (V.M.)
| | - Irina Tihaa
- Institute of Biological Information Processing, IBI-3, Research Center Jülich, 52428 Jülich, Germany; (A.O.); (I.T.); (V.M.)
| | - Vanessa Maybeck
- Institute of Biological Information Processing, IBI-3, Research Center Jülich, 52428 Jülich, Germany; (A.O.); (I.T.); (V.M.)
| | - Sabine Balfanz
- Institute of Biological Information Processing, IBI-1, Research Center Jülich, 52428 Jülich, Germany; (A.K.); (T.G.); (S.B.)
| | - Arnd Baumann
- Institute of Biological Information Processing, IBI-1, Research Center Jülich, 52428 Jülich, Germany; (A.K.); (T.G.); (S.B.)
- Correspondence: ; Tel.: +49-2461-614014
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Koveal D, Rosen PC, Meyer DJ, Díaz-García CM, Wang Y, Cai LH, Chou PJ, Weitz DA, Yellen G. A high-throughput multiparameter screen for accelerated development and optimization of soluble genetically encoded fluorescent biosensors. Nat Commun 2022; 13:2919. [PMID: 35614105 PMCID: PMC9133083 DOI: 10.1038/s41467-022-30685-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 05/11/2022] [Indexed: 12/30/2022] Open
Abstract
Genetically encoded fluorescent biosensors are powerful tools used to track chemical processes in intact biological systems. However, the development and optimization of biosensors remains a challenging and labor-intensive process, primarily due to technical limitations of methods for screening candidate biosensors. Here we describe a screening modality that combines droplet microfluidics and automated fluorescence imaging to provide an order of magnitude increase in screening throughput. Moreover, unlike current techniques that are limited to screening for a single biosensor feature at a time (e.g. brightness), our method enables evaluation of multiple features (e.g. contrast, affinity, specificity) in parallel. Because biosensor features can covary, this capability is essential for rapid optimization. We use this system to generate a high-performance biosensor for lactate that can be used to quantify intracellular lactate concentrations. This biosensor, named LiLac, constitutes a significant advance in metabolite sensing and demonstrates the power of our screening approach.
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Affiliation(s)
- Dorothy Koveal
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Paul C Rosen
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Dylan J Meyer
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Carlos Manlio Díaz-García
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Yongcheng Wang
- Department of Physics and John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
- Liangzhu Laboratory, Zhejiang University Medical Center, 1369 West Wenyi Road, Hangzhou, 311121, China
| | - Li-Heng Cai
- Department of Physics and John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
- Department of Materials Science and Engineering, University of Virginia, Charlottesville, VA, USA
| | - Peter J Chou
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, USA
| | - David A Weitz
- Department of Physics and John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Gary Yellen
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA.
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Absolute measurement of cellular activities using photochromic single-fluorophore biosensors and intermittent quantification. Nat Commun 2022; 13:1850. [PMID: 35387971 PMCID: PMC8986857 DOI: 10.1038/s41467-022-29508-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 03/18/2022] [Indexed: 11/20/2022] Open
Abstract
Genetically-encoded biosensors based on a single fluorescent protein are widely used to visualize analyte levels or enzymatic activities in cells, though usually to monitor relative changes rather than absolute values. We report photochromism-enabled absolute quantification (PEAQ) biosensing, a method that leverages the photochromic properties of biosensors to provide an absolute measure of the analyte concentration or activity. We develop proof-of-concept photochromic variants of the popular GCaMP family of Ca2+ biosensors, and show that these can be used to resolve dynamic changes in the absolute Ca2+ concentration in live cells. We also develop intermittent quantification, a technique that combines absolute aquisitions with fast fluorescence acquisitions to deliver fast but fully quantitative measurements. We also show how the photochromism-based measurements can be expanded to situations where the absolute illumination intensities are unknown. In principle, PEAQ biosensing can be applied to other biosensors with photochromic properties, thereby expanding the possibilities for fully quantitative measurements in complex and dynamic systems. Biosensors often report relative rather than absolute values. Here the authors report a method that utilises the photochromic properties of biosensors to provide an absolute measure of the analyte concentration or activity: photochromism-enabled absolute quantification (PEAQ) biosensing.
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