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Johnson SC, Annamdevula NS, Leavesley SJ, Francis CM, Rich TC. Hyperspectral imaging and dynamic region of interest tracking approaches to quantify localized cAMP signals. Biochem Soc Trans 2024; 52:191-203. [PMID: 38334148 PMCID: PMC11115359 DOI: 10.1042/bst20230352] [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: 11/15/2023] [Revised: 01/10/2024] [Accepted: 01/15/2024] [Indexed: 02/10/2024]
Abstract
Cyclic adenosine monophosphate (cAMP) is a ubiquitous second messenger known to orchestrate a myriad of cellular functions over a wide range of timescales. In the last 20 years, a variety of single-cell sensors have been developed to measure second messenger signals including cAMP, Ca2+, and the balance of kinase and phosphatase activities. These sensors utilize changes in fluorescence emission of an individual fluorophore or Förster resonance energy transfer (FRET) to detect changes in second messenger concentration. cAMP and kinase activity reporter probes have provided powerful tools for the study of localized signals. Studies relying on these and related probes have the potential to further revolutionize our understanding of G protein-coupled receptor signaling systems. Unfortunately, investigators have not been able to take full advantage of the potential of these probes due to the limited signal-to-noise ratio of the probes and the limited ability of standard epifluorescence and confocal microscope systems to simultaneously measure the distributions of multiple signals (e.g. cAMP, Ca2+, and changes in kinase activities) in real time. In this review, we focus on recently implemented strategies to overcome these limitations: hyperspectral imaging and adaptive thresholding approaches to track dynamic regions of interest (ROI). This combination of approaches increases signal-to-noise ratio and contrast, and allows identification of localized signals throughout cells. These in turn lead to the identification and quantification of intracellular signals with higher effective resolution. Hyperspectral imaging and dynamic ROI tracking approaches offer investigators additional tools with which to visualize and quantify multiplexed intracellular signaling systems.
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Affiliation(s)
- Santina C Johnson
- Department of Pharmacology, Frederick P. Whiddon College of Medicine, University of South Alabama, Mobile, AL, U.S.A
- Center for Lung Biology, Frederick P. Whiddon College of Medicine, University of South Alabama, Mobile, AL, U.S.A
| | - Naga S Annamdevula
- Department of Pharmacology, Frederick P. Whiddon College of Medicine, University of South Alabama, Mobile, AL, U.S.A
- Department of Physiology and Cell Biology, Frederick P. Whiddon College of Medicine, University of South Alabama, Mobile, AL, U.S.A
- Center for Lung Biology, Frederick P. Whiddon College of Medicine, University of South Alabama, Mobile, AL, U.S.A
| | - Silas J Leavesley
- Department of Pharmacology, Frederick P. Whiddon College of Medicine, University of South Alabama, Mobile, AL, U.S.A
- Center for Lung Biology, Frederick P. Whiddon College of Medicine, University of South Alabama, Mobile, AL, U.S.A
- Chemical and Biomolecular Engineering, University of South Alabama, Mobile, AL, U.S.A
| | - C Michael Francis
- Department of Physiology and Cell Biology, Frederick P. Whiddon College of Medicine, University of South Alabama, Mobile, AL, U.S.A
- Center for Lung Biology, Frederick P. Whiddon College of Medicine, University of South Alabama, Mobile, AL, U.S.A
| | - Thomas C Rich
- Department of Pharmacology, Frederick P. Whiddon College of Medicine, University of South Alabama, Mobile, AL, U.S.A
- Center for Lung Biology, Frederick P. Whiddon College of Medicine, University of South Alabama, Mobile, AL, U.S.A
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Pfahl A, Polat ST, Köhler H, Gockel I, Melzer A, Chalopin C. Switchable LED-based laparoscopic multispectral system for rapid high-resolution perfusion imaging. JOURNAL OF BIOMEDICAL OPTICS 2023; 28:126002. [PMID: 38094710 PMCID: PMC10718192 DOI: 10.1117/1.jbo.28.12.126002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 11/03/2023] [Accepted: 11/08/2023] [Indexed: 12/18/2023]
Abstract
Significance Multispectral imaging (MSI) is an approach for real-time, quantitative, and non-invasive tissue perfusion measurements. Current laparoscopic systems based on mosaic sensors or filter wheels lack high spatial resolution or acceptable frame rates. Aim To develop a laparoscopic system for MSI-based color video and tissue perfusion imaging during gastrointestinal surgery without compromising spatial or temporal resolution. Approach The system was built with 14 switchable light-emitting diodes in the visible and near-infrared spectral range, a 4K image sensor, and a 10 mm laparoscope. Illumination patterns were created for tissue oxygenation and hemoglobin content monitoring. The system was calibrated to a clinically approved laparoscopic hyperspectral system using linear regression models and evaluated in an occlusion study with 36 volunteers. Results The root mean squared errors between the MSI and reference system were 0.073 for hemoglobin content, 0.039 for oxygenation in deeper tissue layers, and 0.093 for superficial oxygenation. The spatial resolution at a working distance of 45 mm was 156 μ m . The effective frame rate was 20 fps. Conclusions High-resolution perfusion monitoring was successfully achieved. Hardware optimizations will increase the frame rate. Parameter optimizations through alternative illumination patterns, regression, or assumed tissue models are planned. Intraoperative measurements must confirm the suitability during surgery.
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Affiliation(s)
- Annekatrin Pfahl
- Leipzig University, Faculty of Medicine, Innovation Center Computer Assisted Surgery, Leipzig, Germany
| | - Süleyman T. Polat
- Leipzig University, Faculty of Medicine, Innovation Center Computer Assisted Surgery, Leipzig, Germany
| | - Hannes Köhler
- Leipzig University, Faculty of Medicine, Innovation Center Computer Assisted Surgery, Leipzig, Germany
| | - Ines Gockel
- University Hospital of Leipzig, Department of Visceral, Transplant, Thoracic, and Vascular Surgery, Leipzig, Germany
| | - Andreas Melzer
- Leipzig University, Faculty of Medicine, Innovation Center Computer Assisted Surgery, Leipzig, Germany
- University of Dundee, School of Medicine, Institute for Medical Science and Technology, Dundee, United Kingdom
| | - Claire Chalopin
- Leipzig University, Faculty of Medicine, Innovation Center Computer Assisted Surgery, Leipzig, Germany
- University of Applied Sciences and Arts, Faculty of Engineering and Health, Göttingen, Germany
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Sun J, Wu Z, Wang L, Yao Q, Li M, Yao G. Adaptive denoising hyperspectral data for visualization enhancement of intraoperative tissue. JOURNAL OF BIOPHOTONICS 2022; 15:e202200083. [PMID: 35460593 DOI: 10.1002/jbio.202200083] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Revised: 04/21/2022] [Accepted: 04/22/2022] [Indexed: 06/14/2023]
Abstract
The vast amount of reflectance information obtained from the hyperspectral imaging devices offers great opportunities for investigating the function and structure of human tissue. However, the captured hyperspectral data often contain various noises due to the intrinsic imperfection of associated electrical and optical imaging components. This work proposed an automatic total variation algorithm to suppress the noises while preserving the details of the spectral and spatial information. The variation of spectral images at neighboring bands was calculated for regulating the total variation of hyperspectral data so that the spectral-dependent noises can be treated differentially across all bands. Experimental results demonstrated that the proposed method could effectively remove the spectral noises, especially near the ends of those extreme bands. The noise suppressed hyperspectral data could then be used for the visualization enhancement on pathophysiological conditions of intraoperative observed anatomies such as the vessels of brain tissues.
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Affiliation(s)
- Jiuai Sun
- School of Medical Imaging, Shanghai University of Medicine and Health Sciences, Shanghai, China
| | - Zhonghang Wu
- School of Medical Imaging, Shanghai University of Medicine and Health Sciences, Shanghai, China
| | - Le Wang
- Academy for Engineering and Technology, Fudan University, Shanghai, China
| | - Qi Yao
- Academy for Engineering and Technology, Fudan University, Shanghai, China
- Research and Development Department, Zhongshan Fudan Joint Innovation Center, Guangdong, China
| | - Min Li
- Academy for Engineering and Technology, Fudan University, Shanghai, China
| | - Guangyu Yao
- Department of Thoracic Surgery, Zhongshan Hospital, Shanghai, China
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Browning CM, Mayes S, Mayes SA, Rich TC, Leavesley SJ. Microscopy is better in color: development of a streamlined spectral light path for real-time multiplex fluorescence microscopy. BIOMEDICAL OPTICS EXPRESS 2022; 13:3751-3772. [PMID: 35991911 PMCID: PMC9352297 DOI: 10.1364/boe.453657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 05/24/2022] [Accepted: 05/26/2022] [Indexed: 06/15/2023]
Abstract
Spectroscopic image data has provided molecular discrimination for numerous fields including: remote sensing, food safety and biomedical imaging. Despite the various technologies for acquiring spectral data, there remains a trade-off when acquiring data. Typically, spectral imaging either requires long acquisition times to collect an image stack with high spectral specificity or acquisition times are shortened at the expense of fewer spectral bands or reduced spatial sampling. Hence, new spectral imaging microscope platforms are needed to help mitigate these limitations. Fluorescence excitation-scanning spectral imaging is one such new technology, which allows more of the emitted signal to be detected than comparable emission-scanning spectral imaging systems. Here, we have developed a new optical geometry that provides spectral illumination for use in excitation-scanning spectral imaging microscope systems. This was accomplished using a wavelength-specific LED array to acquire spectral image data. Feasibility of the LED-based spectral illuminator was evaluated through simulation and benchtop testing and assessment of imaging performance when integrated with a widefield fluorescence microscope. Ray tracing simulations (TracePro) were used to determine optimal optical component selection and geometry. Spectral imaging feasibility was evaluated using a series of 6-label fluorescent slides. The LED-based system response was compared to a previously tested thin-film tunable filter (TFTF)-based system. Spectral unmixing successfully discriminated all fluorescent components in spectral image data acquired from both the LED and TFTF systems. Therefore, the LED-based spectral illuminator provided spectral image data sets with comparable information content so as to allow identification of each fluorescent component. These results provide proof-of-principle demonstration of the ability to combine output from many discrete wavelength LED sources using a double-mirror (Cassegrain style) optical configuration that can be further modified to allow for high speed, video-rate spectral image acquisition. Real-time spectral fluorescence microscopy would allow monitoring of rapid cell signaling processes (i.e., Ca2+ and other second messenger signaling) and has potential to be translated to clinical imaging platforms.
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Affiliation(s)
- Craig M. Browning
- Chemical and Biomolecular Engineering, University of South Alabama, AL 36688, USA
- Systems Engineering, University of South Alabama, AL 36688, USA
- These authors contributed equally to this work
| | - Samantha Mayes
- Chemical and Biomolecular Engineering, University of South Alabama, AL 36688, USA
- These authors contributed equally to this work
| | - Samuel A. Mayes
- Chemical and Biomolecular Engineering, University of South Alabama, AL 36688, USA
- Systems Engineering, University of South Alabama, AL 36688, USA
| | - Thomas C. Rich
- Pharmacology, University of South Alabama, AL 36688, USA
- Center for Lung Biology, University of South Alabama, AL 36688, USA
| | - Silas J. Leavesley
- Chemical and Biomolecular Engineering, University of South Alabama, AL 36688, USA
- Pharmacology, University of South Alabama, AL 36688, USA
- Center for Lung Biology, University of South Alabama, AL 36688, USA
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Johnson S, Pleshinger D, Jalkh J, Ijaz Z, Annamdevula N, Britain AL, Francis CM, Deshpande D, Leavesley SJ, Rich TC. Measurement of agonist-induced Ca 2+ signals in human airway smooth muscle cells using excitation scan-based hyperspectral imaging and image analysis approaches. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2022; 11964:119640J. [PMID: 35755606 PMCID: PMC9215168 DOI: 10.1117/12.2608276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Ca2+ and cAMP are ubiquitous second messengers known to differentially regulate a variety of cellular functions over a wide range of timescales. Studies from a variety of groups support the hypothesis that these signals can be localized to discrete locations within cells, and that this subcellular localization is a critical component of signaling specificity. However, to date, it has been difficult to track second messenger signals at multiple locations. To overcome this limitation, we utilized excitation scan-based hyperspectral imaging approaches to track second messenger signals as well as labeled cellular structures and/or proteins in the same cell. We have previously reported that hyperspectral imaging techniques improve the signal-to-noise ratios of both fluorescence measurements, and are thus well suited for the measurement of localized Ca2+ signals. We investigated the spatial spread and intensities of agonist-induced Ca2+ signals in primary human airway smooth muscle cells (HASMCs) using the Ca2+ indicator Cal520. We measured responses triggered by three agonists, carbachol, histamine, and chloroquine. We utilized custom software coded in MATLAB and Python to assess agonist induced changes in Ca2+ levels. Software algorithms removed the background and applied correction coefficients to spectral data prior to linear unmixing, spatial and temporal filtering, adaptive thresholding, and automated region of interest (ROI) detection. All three agonists triggered transient Ca2+ responses that were spatially and temporally complex. We are currently analyzing differences in both ROI area and intensity distributions triggered by these agonists. This work was supported by NIH awards P01HL066299, K25HL136869, and R01HL137030 and NSF award MRI1725937.
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Affiliation(s)
| | | | - Josephine Jalkh
- Biomedical Sciences, University of South Alabama, Mobile, AL 36688
| | - Zara Ijaz
- Pharmacology, University of South Alabama, Mobile, AL 36688
| | | | | | - C. Michael Francis
- Physiology and Cell Biology, University of South Alabama, Mobile, AL 36688
| | - Deepak Deshpande
- Center for Translational Medicine, Thomas Jefferson University, Philadelphia, PA 19107
| | - Silas J. Leavesley
- Pharmacology, University of South Alabama, Mobile, AL 36688,Chemical and Biomolecular Engineering, University of South Alabama, Mobile, AL 36688
| | - Thomas C. Rich
- Pharmacology, University of South Alabama, Mobile, AL 36688
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