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Kostyuk AI, Rapota DD, Morozova KI, Fedotova AA, Jappy D, Semyanov AV, Belousov VV, Brazhe NA, Bilan DS. Modern optical approaches in redox biology: Genetically encoded sensors and Raman spectroscopy. Free Radic Biol Med 2024; 217:68-115. [PMID: 38508405 DOI: 10.1016/j.freeradbiomed.2024.03.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 02/10/2024] [Accepted: 03/13/2024] [Indexed: 03/22/2024]
Abstract
The objective of the current review is to summarize the current state of optical methods in redox biology. It consists of two parts, the first is dedicated to genetically encoded fluorescent indicators and the second to Raman spectroscopy. In the first part, we provide a detailed classification of the currently available redox biosensors based on their target analytes. We thoroughly discuss the main architecture types of these proteins, the underlying engineering strategies for their development, the biochemical properties of existing tools and their advantages and disadvantages from a practical point of view. Particular attention is paid to fluorescence lifetime imaging microscopy as a possible readout technique, since it is less prone to certain artifacts than traditional intensiometric measurements. In the second part, the characteristic Raman peaks of the most important redox intermediates are listed, and examples of how this knowledge can be implemented in biological studies are given. This part covers such fields as estimation of the redox states and concentrations of Fe-S clusters, cytochromes, other heme-containing proteins, oxidative derivatives of thiols, lipids, and nucleotides. Finally, we touch on the issue of multiparameter imaging, in which biosensors are combined with other visualization methods for simultaneous assessment of several cellular parameters.
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Affiliation(s)
- Alexander I Kostyuk
- M.M. Shemyakin and Yu.A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia; Pirogov Russian National Research Medical University, 117997, Moscow, Russia
| | - Diana D Rapota
- M.M. Shemyakin and Yu.A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - Kseniia I Morozova
- Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, 119234, Russia
| | - Anna A Fedotova
- M.M. Shemyakin and Yu.A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia; Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, 119234, Russia
| | - David Jappy
- Federal Center of Brain Research and Neurotechnologies, Federal Medical Biological Agency, Moscow, 117997, Russia
| | - Alexey V Semyanov
- M.M. Shemyakin and Yu.A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia; Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, 119234, Russia; Sechenov First Moscow State Medical University, Moscow, 119435, Russia; College of Medicine, Jiaxing University, Jiaxing, Zhejiang Province, 314001, China
| | - Vsevolod V Belousov
- M.M. Shemyakin and Yu.A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia; Pirogov Russian National Research Medical University, 117997, Moscow, Russia; Federal Center of Brain Research and Neurotechnologies, Federal Medical Biological Agency, Moscow, 117997, Russia; Life Improvement by Future Technologies (LIFT) Center, Skolkovo, Moscow, 143025, Russia
| | - Nadezda A Brazhe
- M.M. Shemyakin and Yu.A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia; Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, 119234, Russia.
| | - Dmitry S Bilan
- M.M. Shemyakin and Yu.A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia; Pirogov Russian National Research Medical University, 117997, Moscow, Russia.
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Costa S, Fang Q, Farrell T, Dao E, Farquharson M. Time-resolved fluorescence and diffuse reflectance for lung squamous carcinoma margin detection. Lasers Surg Med 2024; 56:279-287. [PMID: 38357847 DOI: 10.1002/lsm.23761] [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: 09/11/2023] [Revised: 12/26/2023] [Accepted: 01/13/2024] [Indexed: 02/16/2024]
Abstract
OBJECTIVES A major challenge in non-small cell lung cancer surgery is the occurrence of positive tumor margins. This may lead to the need for additional surgeries and has been linked to poor patient prognosis. This study aims to develop an in vivo surgical tool that can differentiate cancerous from noncancerous lung tissue at the margin. METHODS A time-resolved fluorescence and diffuse reflectance bimodal device was used to measure the lifetime, spectra, and intensities of endogenous fluorophores as well as optical properties of lung tissue. The tumor and fibrotic tissue data, each containing 36 samples, was obtained from patients who underwent surgical removal of lung tissue after being diagnosed with squamous carcinoma but before any other treatment was administered. The normal lung tissue data were obtained from nine normal tissue samples. RESULTS The results show a statistically significant difference between cancerous and noncancerous tissue. The results also show a difference in metabolic related optical properties between fibrotic and normal lung tissue samples. CONCLUSIONS This work demonstrates the feasibility of a device that can differentiate cancerous and noncancerous lung tissue for patients diagnosed with squamous cell carcinoma.
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Affiliation(s)
- Sarah Costa
- Department of Physics, McMaster University, Ontario, Hamilton, Canada
| | - Qiyin Fang
- Department of Engineering Physics, Faculty of Engineering, McMaster University, Ontario, Hamilton, Canada
| | - Thomas Farrell
- Radiation Physics Program, Juravinski Cancer Centre, Ontario, Hamilton, Canada
| | - Erica Dao
- Department of Physics, McMaster University, Ontario, Hamilton, Canada
| | - Michael Farquharson
- Department of Interdisciplinary Science, McMaster University, Ontario, Hamilton, Canada
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3
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Gnaiger E. Complex II ambiguities-FADH 2 in the electron transfer system. J Biol Chem 2024; 300:105470. [PMID: 38118236 PMCID: PMC10772739 DOI: 10.1016/j.jbc.2023.105470] [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: 07/03/2023] [Revised: 11/01/2023] [Accepted: 11/06/2023] [Indexed: 12/22/2023] Open
Abstract
The prevailing notion that reduced cofactors NADH and FADH2 transfer electrons from the tricarboxylic acid cycle to the mitochondrial electron transfer system creates ambiguities regarding respiratory Complex II (CII). CII is the only membrane-bound enzyme in the tricarboxylic acid cycle and is part of the electron transfer system of the mitochondrial inner membrane feeding electrons into the coenzyme Q-junction. The succinate dehydrogenase subunit SDHA of CII oxidizes succinate and reduces the covalently bound prosthetic group FAD to FADH2 in the canonical forward tricarboxylic acid cycle. However, several graphical representations of the electron transfer system depict FADH2 in the mitochondrial matrix as a substrate to be oxidized by CII. This leads to the false conclusion that FADH2 from the β-oxidation cycle in fatty acid oxidation feeds electrons into CII. In reality, dehydrogenases of fatty acid oxidation channel electrons to the Q-junction but not through CII. The ambiguities surrounding Complex II in the literature and educational resources call for quality control, to secure scientific standards in current communications of bioenergetics, and ultimately support adequate clinical applications. This review aims to raise awareness of the inherent ambiguity crisis, complementing efforts to address the well-acknowledged issues of credibility and reproducibility.
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Hu L, Wang N, Bryant JD, Liu L, Xie L, West AP, Walsh AJ. Label-free spatially maintained measurements of metabolic phenotypes in cells. Front Bioeng Biotechnol 2023; 11:1293268. [PMID: 38090715 PMCID: PMC10715269 DOI: 10.3389/fbioe.2023.1293268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 11/14/2023] [Indexed: 02/01/2024] Open
Abstract
Metabolic reprogramming at a cellular level contributes to many diseases including cancer, yet few assays are capable of measuring metabolic pathway usage by individual cells within living samples. Here, autofluorescence lifetime imaging is combined with single-cell segmentation and machine-learning models to predict the metabolic pathway usage of cancer cells. The metabolic activities of MCF7 breast cancer cells and HepG2 liver cancer cells were controlled by growing the cells in culture media with specific substrates and metabolic inhibitors. Fluorescence lifetime images of two endogenous metabolic coenzymes, reduced nicotinamide adenine dinucleotide (NADH) and oxidized flavin adenine dinucleotide (FAD), were acquired by a multi-photon fluorescence lifetime microscope and analyzed at the cellular level. Quantitative changes of NADH and FAD lifetime components were observed for cells using glycolysis, oxidative phosphorylation, and glutaminolysis. Conventional machine learning models trained with the autofluorescence features classified cells as dependent on glycolytic or oxidative metabolism with 90%-92% accuracy. Furthermore, adapting convolutional neural networks to predict cancer cell metabolic perturbations from the autofluorescence lifetime images provided improved performance, 95% accuracy, over traditional models trained via extracted features. Additionally, the model trained with the lifetime features of cancer cells could be transferred to autofluorescence lifetime images of T cells, with a prediction that 80% of activated T cells were glycolytic, and 97% of quiescent T cells were oxidative. In summary, autofluorescence lifetime imaging combined with machine learning models can detect metabolic perturbations between glycolysis and oxidative metabolism of living samples at a cellular level, providing a label-free technology to study cellular metabolism and metabolic heterogeneity.
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Affiliation(s)
- Linghao Hu
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, United States
| | - Nianchao Wang
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, United States
| | - Joshua D. Bryant
- Microbial Pathogenesis and Immunology, Health Science Center, Texas A&M University, College Station, TX, United States
| | - Lin Liu
- Department of Nutrition, Texas A&M University, College Station, TX, United States
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, United States
| | - Linglin Xie
- Department of Nutrition, Texas A&M University, College Station, TX, United States
| | - A. Phillip West
- Microbial Pathogenesis and Immunology, Health Science Center, Texas A&M University, College Station, TX, United States
| | - Alex J. Walsh
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, United States
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Klontz E, Obi JO, Wang Y, Glendening G, Carr J, Tsibouris C, Buddula S, Nallar S, Soares AS, Beckett D, Redzic JS, Eisenmesser E, Palm C, Schmidt K, Scudder AH, Obiorah T, Essuman K, Milbrandt J, Diantonio A, Ray K, Snyder MLD, Deredge D, Snyder GA. The structure of NAD + consuming protein Acinetobacter baumannii TIR domain shows unique kinetics and conformations. J Biol Chem 2023; 299:105290. [PMID: 37758001 PMCID: PMC10641520 DOI: 10.1016/j.jbc.2023.105290] [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: 05/25/2023] [Revised: 09/05/2023] [Accepted: 09/13/2023] [Indexed: 09/29/2023] Open
Abstract
Toll-like and interleukin-1/18 receptor/resistance (TIR) domain-containing proteins function as important signaling and immune regulatory molecules. TIR domain-containing proteins identified in eukaryotic and prokaryotic species also exhibit NAD+ hydrolase activity in select bacteria, plants, and mammalian cells. We report the crystal structure of the Acinetobacter baumannii TIR domain protein (AbTir-TIR) with confirmed NAD+ hydrolysis and map the conformational effects of its interaction with NAD+ using hydrogen-deuterium exchange-mass spectrometry. NAD+ results in mild decreases in deuterium uptake at the dimeric interface. In addition, AbTir-TIR exhibits EX1 kinetics indicative of large cooperative conformational changes, which are slowed down upon substrate binding. Additionally, we have developed label-free imaging using the minimally invasive spectroscopic method 2-photon excitation with fluorescence lifetime imaging, which shows differences in bacteria expressing native and mutant NAD+ hydrolase-inactivated AbTir-TIRE208A protein. Our observations are consistent with substrate-induced conformational changes reported in other TIR model systems with NAD+ hydrolase activity. These studies provide further insight into bacterial TIR protein mechanisms and their varying roles in biology.
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Affiliation(s)
- Erik Klontz
- Division of Vaccine Research, Institute of Human Virology, School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | - Juliet O Obi
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, USA
| | - Yajing Wang
- Division of Vaccine Research, Institute of Human Virology, School of Medicine, University of Maryland, Baltimore, Maryland, USA; Department of Physiology, School of Basic Medical Sciences and Clinical Pharmacy, China Pharmaceutical University, Nanjing, P.R. China
| | - Gabrielle Glendening
- Division of Vaccine Research, Institute of Human Virology, School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | - Jahid Carr
- Division of Vaccine Research, Institute of Human Virology, School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | - Constantine Tsibouris
- Division of Vaccine Research, Institute of Human Virology, School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | - Sahthi Buddula
- Division of Vaccine Research, Institute of Human Virology, School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | - Shreeram Nallar
- Division of Vaccine Research, Institute of Human Virology, School of Medicine, University of Maryland, Baltimore, Maryland, USA; Department of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | - Alexei S Soares
- Brookhaven National Laboratory, National Synchrotron Light Source II, Structural Biology Program, Upton, New York, USA
| | - Dorothy Beckett
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland, USA
| | - Jasmina S Redzic
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Colorado Denver, School of Medicine, Aurora, Colorado, USA
| | - Elan Eisenmesser
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Colorado Denver, School of Medicine, Aurora, Colorado, USA
| | - Cheyenne Palm
- Department of Biological Sciences, Towson University, Towson, Maryland, USA
| | - Katrina Schmidt
- Department of Biological Sciences, Towson University, Towson, Maryland, USA
| | - Alexis H Scudder
- Department of Biological Sciences, Towson University, Towson, Maryland, USA
| | - Trinity Obiorah
- Department of Biological Sciences, Towson University, Towson, Maryland, USA
| | - Kow Essuman
- Department of Developmental Biology, Washington University School of Medicine, St Louis, Missouri, USA; Department of Neurosurgery, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Jeffrey Milbrandt
- Department of Developmental Biology, Washington University School of Medicine, St Louis, Missouri, USA
| | - Aaron Diantonio
- Department of Developmental Biology, Washington University School of Medicine, St Louis, Missouri, USA
| | - Krishanu Ray
- Division of Vaccine Research, Institute of Human Virology, School of Medicine, University of Maryland, Baltimore, Maryland, USA; Department of Biochemistry and Molecular Biology at the University of Maryland, School of Medicine, Baltimore, Maryland, USA
| | | | - Daniel Deredge
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, USA
| | - Greg A Snyder
- Division of Vaccine Research, Institute of Human Virology, School of Medicine, University of Maryland, Baltimore, Maryland, USA; Department of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, Maryland, USA.
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He G, Liu M, Wang F, Sun S, Cao Y, Sun Y, Ma S, Wang Y. Non-invasive assessment of hair regeneration in androgenetic alopecia mice in vivo using two-photon and second harmonic generation imaging. BIOMEDICAL OPTICS EXPRESS 2023; 14:5870-5885. [PMID: 38021124 PMCID: PMC10659803 DOI: 10.1364/boe.503312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 09/15/2023] [Accepted: 09/20/2023] [Indexed: 12/01/2023]
Abstract
The identification of crucial targets for hair regrowth in androgenetic alopecia (AGA) involves determining important characteristics and different stages during the process of hair follicle regeneration. Traditional methods for assessing key features and different stages of hair follicle primarily involve taking skin tissue samples and determining them through various staining or other methods. However, non-invasive assessment methods have been long sought. Therefore, in this study, endogenous fluorescence signals from skin keratin and second harmonic signals from skin collagen fibers were utilized as probes, two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) imaging techniques were employed to non-invasively assess hair shafts and collagen fibers in AGA mice in vivo. The TPEF imaging technique revealed that the alternation of new and old hair shafts and the different stages of the growth period in AGA mice were delayed. In addition, SHG imaging found testosterone reduced hair follicle area and miniaturized hair follicles. The non-invasive TPEF and SHG imaging techniques provided important methodologies for determining significant characteristics and different stages of the growth cycle in AGA mice, which will facilitate future non-invasive assessments on human scalps in vivo and reduce the use of animal testing.
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Affiliation(s)
- Gaiying He
- Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Menghua Liu
- School of Life Science, Beijing University of Chinese Medicine, Beijing 102488, China
| | - Fenglong Wang
- School of Life Science, Beijing University of Chinese Medicine, Beijing 102488, China
| | - Shuqing Sun
- Institute of Biopharmaceutical and Healthcare Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Yu Cao
- Institute of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing 100091, China
| | - Yanan Sun
- Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Shuhua Ma
- Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Yi Wang
- Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing 100700, China
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Snyder GA, Kumar S, Lewis GK, Ray K. Two-photon fluorescence lifetime imaging microscopy of NADH metabolism in HIV-1 infected cells and tissues. Front Immunol 2023; 14:1213180. [PMID: 37662898 PMCID: PMC10468605 DOI: 10.3389/fimmu.2023.1213180] [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: 04/27/2023] [Accepted: 07/21/2023] [Indexed: 09/05/2023] Open
Abstract
Rapid detection of microbial-induced cellular changes during the course of an infection is critical to understanding pathogenesis and immunological homeostasis. In the last two decades, fluorescence imaging has received significant attention for its ability to help characterize microbial induced cellular and tissue changes in in vitro and in vivo settings. However, most of these methods rely on the covalent conjugation of large exogenous probes and detection methods based on intensity-based imaging. Here, we report a quantitative, intrinsic, label-free, and minimally invasive method based on two-photon fluorescence lifetime (FLT) imaging microscopy (2p-FLIM) for imaging 1,4-dihydro-nicotinamide adenine dinucleotide (NADH) metabolism of virally infected cells and tissue sections. To better understand virally induced cellular and tissue changes in metabolism we have used 2p-FLIM to study differences in NADH intensity and fluorescence lifetimes in HIV-1 infected cells and tissues. Differences in NADH fluorescence lifetimes are associated with cellular changes in metabolism and changes in cellular metabolism are associated with HIV-1 infection. NADH is a critical co-enzyme and redox regulator and an essential biomarker in the metabolic processes. Label-free 2p-FLIM application and detection of NADH fluorescence using viral infection systems are in their infancy. In this study, the application of the 2p-FLIM assay and quantitative analyses of HIV-1 infected cells and tissue sections reveal increased fluorescence lifetime and higher enzyme-bound NADH fraction suggesting oxidative phosphorylation (OxPhos) compared to uninfected cells and tissues. 2p-FLIM measurements improve signal to background, fluorescence specificity, provide spatial and temporal resolution of intracellular structures, and thus, are suitable for quantitative studies of cellular functions and tissue morphology. Furthermore, 2p-FLIM allows distinguishing free and bound populations of NADH by their different fluorescence lifetimes within single infected cells. Accordingly, NADH fluorescence measurements of individual single cells should provide necessary insight into the heterogeneity of metabolic activity of infected cells. Implementing 2p-FLIM to viral infection systems measuring NADH fluorescence at the single or subcellular level within a tissue can provide visual evidence, localization, and information in a real-time diagnostic or therapeutic metabolic workflow.
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Affiliation(s)
- Greg A. Snyder
- Division of Vaccine Research, Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Sameer Kumar
- Division of Vaccine Research, Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - George K. Lewis
- Division of Vaccine Research, Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Krishanu Ray
- Division of Vaccine Research, Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, United States
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Zhang C, Le Dévédec SE, Ali A, Hankemeier T. Single-cell metabolomics by mass spectrometry: ready for primetime? Curr Opin Biotechnol 2023; 82:102963. [PMID: 37356380 DOI: 10.1016/j.copbio.2023.102963] [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: 02/08/2023] [Revised: 04/17/2023] [Accepted: 05/23/2023] [Indexed: 06/27/2023]
Abstract
Single-cell metabolomics (SCMs) is a powerful tool for studying cellular heterogeneity by providing insight into the differences between individual cells. With the development of a set of promising SCMs pipelines, this maturing technology is expected to be widely used in biomedical research. However, before SCMs is ready for primetime, there are some challenges to overcome. In this review, we summarize the trends and challenges in the development of SCMs. We also highlight the latest methodologies, applications, and sketch the perspective for integration with other omics and imaging approaches.
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Affiliation(s)
- Congrou Zhang
- Metabolomics and Analytics Center, Leiden Academic Centre of Drug Research, Leiden University, Leiden, the Netherlands
| | - Sylvia E Le Dévédec
- Division of Drug Discovery and Safety, Leiden Academic Centre of Drug Research, Leiden University, Leiden, the Netherlands
| | - Ahmed Ali
- Metabolomics and Analytics Center, Leiden Academic Centre of Drug Research, Leiden University, Leiden, the Netherlands.
| | - Thomas Hankemeier
- Metabolomics and Analytics Center, Leiden Academic Centre of Drug Research, Leiden University, Leiden, the Netherlands.
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9
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Penjweini R, Pasut A, Roarke B, Alspaugh G, Sackett DL, Knutson JR. High resolution spatial investigation of intracellular oxygen in muscle cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.18.548845. [PMID: 37781589 PMCID: PMC10541121 DOI: 10.1101/2023.07.18.548845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
Molecular oxygen (O 2 ) is one of the most functionally relevant metabolites. O 2 is essential for mito-chondrial aerobic respiration. Changes in O 2 affect muscle metabolism and play a critical role in the maintenance of skeletal muscle mass, with lack of sufficient O 2 resulting in detrimental loss of muscle mass and function. How exactly O 2 is used by muscle cells is less known, mainly due to the lack of tools to address O 2 dynamics at the cellular level. Here we discuss a new imaging method for the real time quantification of intracellular O 2 in muscle cells based on a genetically encoded O 2 -responsive sensor, Myoglobin-mCherry. We show that we can spatially resolve and quantify intracellular O 2 concentration in single muscle cells and that the spatiotemporal O 2 gradient measured by the sensor is linked to, and reflects, functional metabolic changes occurring during the process of muscle differentiation. Highlights Real time quantitation of intracellular oxygen with spatial resolutionIdentification of metabolically active sites in single cellsOxygen metabolism is linked to muscle differentiation.
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10
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Mori MP, Penjweini R, Ma J, Alspaugh G, Andreoni A, Kim YC, Wang PY, Knutson JR, Hwang PM. Mitochondrial respiration reduces exposure of the nucleus to oxygen. J Biol Chem 2023; 299:103018. [PMID: 36796514 PMCID: PMC10011062 DOI: 10.1016/j.jbc.2023.103018] [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: 04/05/2022] [Revised: 01/23/2023] [Accepted: 01/24/2023] [Indexed: 02/16/2023] Open
Abstract
The endosymbiotic theory posits that ancient eukaryotic cells engulfed O2-consuming prokaryotes, which protected them against O2 toxicity. Previous studies have shown that cells lacking cytochrome c oxidase (COX), required for respiration, have increased DNA damage and reduced proliferation, which could be improved by reducing O2 exposure. With recently developed fluorescence lifetime microscopy (FLIM)-based probes demonstrating that the mitochondrial compartment has lower [O2] than the cytosol, we hypothesized that the perinuclear distribution of mitochondria in cells may create a barrier for O2 to access the nuclear core, potentially affecting cellular physiology and maintaining genomic integrity. To test this hypothesis, we utilized myoglobin (MB)-mCherry FLIM O2 sensors without subcellular targeting ("cytosol") or with targeting to the mitochondrion or nucleus for measuring their localized O2 homeostasis. Our results showed that, similar to the mitochondria, the nuclear [O2] was reduced by ∼20-40% compared to the cytosol under imposed O2 levels of ∼0.5-18.6%. Pharmacologic inhibition of respiration increased nuclear O2 levels, and reconstituting O2 consumption by COX reversed this increase. Similarly, genetic disruption of respiration by deleting SCO2, a gene essential for COX assembly, or restoring COX activity in SCO2-/- cells by transducing with SCO2 cDNA also replicated these changes in nuclear O2 levels. The results were further supported by the expression of genes known to be affected by cellular O2 availability. Our study reveals the potential for dynamic regulation of nuclear O2 levels by mitochondrial respiratory activity, which in turn could affect oxidative stress and cellular processes such as neurodegeneration and aging.
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Affiliation(s)
- Mateus Prates Mori
- Cardiovascular Branch, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Rozhin Penjweini
- Laboratory of Advanced Microscopy and Biophotonics, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Jin Ma
- Cardiovascular Branch, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Greg Alspaugh
- Laboratory of Advanced Microscopy and Biophotonics, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Alessio Andreoni
- Laboratory of Advanced Microscopy and Biophotonics, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA; Department of Biochemistry and Molecular Medicine, University of California, Davis, California, USA
| | - Young-Chae Kim
- Cardiovascular Branch, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Ping-Yuan Wang
- Cardiovascular Branch, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Jay R Knutson
- Laboratory of Advanced Microscopy and Biophotonics, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Paul M Hwang
- Cardiovascular Branch, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA.
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11
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Litvinov I, Salova A, Aksenov N, Kornilova E, Belyaeva T. Microenvironmental Impact on InP/ZnS-Based Quantum Dots in In Vitro Models and in Living Cells: Spectrally- and Time-Resolved Luminescence Analysis. Int J Mol Sci 2023; 24:ijms24032699. [PMID: 36769021 PMCID: PMC9916881 DOI: 10.3390/ijms24032699] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/15/2023] [Accepted: 01/21/2023] [Indexed: 02/04/2023] Open
Abstract
Quantum dots (QDs) have attracted great attention as tools for theranostics that combine the possibility of simultaneous biological target visualization and medicine delivery. Here, we address whether core/shell InP/ZnS QDs (InP-QDs) may be an alternative to toxic Cd-based QDs. We analyze InP-QD photophysical characteristics in cell culture medium, salt solutions, and directly in the cells. It was demonstrated that InP-QDs were internalized into endolysosomes in HeLa and A549 cells with dynamics similar to Cd-based QDs of the same design, but the two cell lines accumulated them with different efficiencies. InP-QDs were reliably detected in the endosomes despite their low quantum yields. Cell culture medium efficiently decreased the InP-QD photoluminescence lifetime by 50%, acidic pH (4.0) had a moderate effect (20-25% reduction), and quenching by salt solutions typical of intra-endosomal medium composition resulted in a decrease of about 10-15%. The single-vesicle fluorescence-lifetime imaging microscopy analysis of QDs inside and outside the cells shows that the scatter between endosomes in the same cell can be significant, which indicates the complex impact of the abovementioned factors on the state of InP-QDs. The PI test and MTT test demonstrate that InP-QDs are toxic for both cell lines at concentrations higher than 20 nM. Possible reasons for InP-QD toxicity are discussed.
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Affiliation(s)
- Ilia Litvinov
- Institute of Cytology, Russian Academy of Sciences,194064 Saint Petersburg, Russia
| | - Anna Salova
- Institute of Cytology, Russian Academy of Sciences,194064 Saint Petersburg, Russia
| | - Nikolay Aksenov
- Institute of Cytology, Russian Academy of Sciences,194064 Saint Petersburg, Russia
| | - Elena Kornilova
- Institute of Cytology, Russian Academy of Sciences,194064 Saint Petersburg, Russia
- Higher School of Biomedical Systems and Technologies, Peter the Great St. Petersburg Polytechnic University, 195251 Saint Petersburg, Russia
- Correspondence: ; Tel.: +7-921-302-59-05
| | - Tatiana Belyaeva
- Institute of Cytology, Russian Academy of Sciences,194064 Saint Petersburg, Russia
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12
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Computational Modeling and Imaging of the Intracellular Oxygen Gradient. Int J Mol Sci 2022; 23:ijms232012597. [PMID: 36293452 PMCID: PMC9604273 DOI: 10.3390/ijms232012597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 10/13/2022] [Accepted: 10/17/2022] [Indexed: 11/30/2022] Open
Abstract
Computational modeling can provide a mechanistic and quantitative framework for describing intracellular spatial heterogeneity of solutes such as oxygen partial pressure (pO2). This study develops and evaluates a finite-element model of oxygen-consuming mitochondrial bioenergetics using the COMSOL Multiphysics program. The model derives steady-state oxygen (O2) distributions from Fickian diffusion and Michaelis–Menten consumption kinetics in the mitochondria and cytoplasm. Intrinsic model parameters such as diffusivity and maximum consumption rate were estimated from previously published values for isolated and intact mitochondria. The model was compared with experimental data collected for the intracellular and mitochondrial pO2 levels in human cervical cancer cells (HeLa) in different respiratory states and under different levels of imposed pO2. Experimental pO2 gradients were measured using lifetime imaging of a Förster resonance energy transfer (FRET)-based O2 sensor, Myoglobin-mCherry, which offers in situ real-time and noninvasive measurements of subcellular pO2 in living cells. On the basis of these results, the model qualitatively predicted (1) the integrated experimental data from mitochondria under diverse experimental conditions, and (2) the impact of changes in one or more mitochondrial processes on overall bioenergetics.
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13
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Advances in measuring cancer cell metabolism with subcellular resolution. Nat Methods 2022; 19:1048-1063. [PMID: 36008629 DOI: 10.1038/s41592-022-01572-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Accepted: 07/05/2022] [Indexed: 11/08/2022]
Abstract
Characterizing metabolism in cancer is crucial for understanding tumor biology and for developing potential therapies. Although most metabolic investigations analyze averaged metabolite levels from all cell compartments, subcellular metabolomics can provide more detailed insight into the biochemical processes associated with the disease. Methodological limitations have historically prevented the wider application of subcellular metabolomics in cancer research. Recently, however, ways to distinguish and identify metabolic pathways within organelles have been developed, including state-of-the-art methods to monitor metabolism in situ (such as mass spectrometry-based imaging, Raman spectroscopy and fluorescence microscopy), to isolate key organelles via new approaches and to use tailored isotope-tracing strategies. Herein, we examine the advantages and limitations of these developments and look to the future of this field of research.
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14
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McCulley DJ, Jensen EA, Sucre JMS, McKenna S, Sherlock LG, Dobrinskikh E, Wright CJ. Racing against time: leveraging preclinical models to understand pulmonary susceptibility to perinatal acetaminophen exposures. Am J Physiol Lung Cell Mol Physiol 2022; 323:L1-L13. [PMID: 35503238 PMCID: PMC9208439 DOI: 10.1152/ajplung.00080.2022] [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: 03/07/2022] [Revised: 04/20/2022] [Accepted: 04/25/2022] [Indexed: 11/22/2022] Open
Abstract
Over the past decade, clinicians have increasingly prescribed acetaminophen (APAP) for patients in the neonatal intensive care unit (NICU). Acetaminophen has been shown to reduce postoperative opiate burden, and may provide similar efficacy for closure of the patent ductus arteriosus (PDA) as nonsteroidal anti-inflammatory drugs (NSAIDs). Despite these potential benefits, APAP exposures have spread to increasingly less mature infants, a highly vulnerable population for whom robust pharmacokinetic and pharmacodynamic data for APAP are lacking. Concerningly, preclinical studies suggest that perinatal APAP exposures may result in unanticipated adverse effects that are unique to the developing lung. In this review, we discuss the clinical observations linking APAP exposures to adverse respiratory outcomes and the preclinical data demonstrating a developmental susceptibility to APAP-induced lung injury. We show how clinical observations linking perinatal APAP exposures to pulmonary injury have been taken to the bench to produce important insights into the potential mechanisms underlying these findings. We argue that the available data support a more cautious approach to APAP use in the NICU until large randomized controlled trials provide appropriate safety and efficacy data.
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Affiliation(s)
- David J McCulley
- Division of Neonatology, Department of Pediatrics, University of California, San Diego, California
| | - Erik A Jensen
- Division of Neonatology, Department of Pediatrics, The Children's Hospital of Philadelphia, The University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | | | - Sarah McKenna
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | - Laura G Sherlock
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | - Evgenia Dobrinskikh
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
- Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado
| | - Clyde J Wright
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
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15
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Wu CC, Wang CJ, Chang CLT, Shiku H, Wang YR, Yan JD, Ding SJ. Dissolved Oxygen-Sensing Chip Integrating an Open Container Connected with a Position-Raised Channel for Estimation of Cellular Mitochondrial Activity. ACS Sens 2022; 7:1808-1818. [PMID: 35748570 DOI: 10.1021/acssensors.1c02287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The measurement of oxygen consumption of adherent cells is a profoundly important issue for estimating the bioenergetic health and metabolism activity of cells. The study describes the construction of a microfluidic chip consisting of an open container connected with a position-raised channel and dissolved oxygen (DO)-sensing gold ultramicroelectrodes for quantifying the oxygen consumption rate (OCR) of adherent cells. The microfluidic chip design can reduce the action of shear force on the adherent cells during medium replacement. The residual concentration of analytes in the open container was only 4.4% after solution replacement via the position-raised channel. The DO reduction current measured by ultramicroelectrodes averaged in the range of 40-60 s presented high reproducibility with a 1.1% relative standard deviation suitable for OCR calculation. After short-term (90 min) cultivation, the microfluidic chip can monitor the time-dependent change in the OCR of 3T3-L1 cells for several hours by repeatedly replacing the culture medium or with the stimulation of different mitochondrial inhibitors. The presented microfluidic cell-based chip has great promise for drug screening and chemosensitivity testing by measuring OCR to evaluate the mitochondrial function of adherent cells.
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Affiliation(s)
- Ching-Chou Wu
- Department of Bio-Industrial Mechatronics Engineering, National Chung Hsing University, Taichung City 402, Taiwan.,Innovation and Development Center of Sustainable Agriculture, National Chung Hsing University, Taichung City 402, Taiwan
| | - Chieh-Jen Wang
- Department of Bio-Industrial Mechatronics Engineering, National Chung Hsing University, Taichung City 402, Taiwan
| | | | - Hitoshi Shiku
- Graduate School of Engineering, Tohoku University, 6-6-11 Aramaki-aza Aoba, Aoba-ku, Sendai 980-8579, Japan
| | - Yu-Ren Wang
- Department of Bio-Industrial Mechatronics Engineering, National Chung Hsing University, Taichung City 402, Taiwan
| | - Jia-De Yan
- Department of Bio-Industrial Mechatronics Engineering, National Chung Hsing University, Taichung City 402, Taiwan
| | - Shinn-Jyh Ding
- Department of Dentistry, Chung Shan Medical University Hospital, Taichung City 402, Taiwan, ROC.,Institute of Oral Science, Chung Shan Medical University, Taichung City 402, Taiwan
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16
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Penjweini R, Roarke B, Alspaugh G, Link KA, Andreoni A, Mori MP, Hwang PM, Sackett DL, Knutson JR. Intracellular imaging of metmyoglobin and oxygen using new dual purpose probe EYFP-Myoglobin-mCherry. JOURNAL OF BIOPHOTONICS 2022; 15:e202100166. [PMID: 34689421 PMCID: PMC8901566 DOI: 10.1002/jbio.202100166] [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: 05/29/2021] [Revised: 10/04/2021] [Accepted: 10/13/2021] [Indexed: 06/13/2023]
Abstract
The biological relevance of nitric oxide (NO) and reactive oxygen species (ROS) in signaling, metabolic regulation, and disease treatment has become abundantly clear. The dramatic change in NO/ROS processing that accompanies a changing oxygen landscape calls for new imaging tools that can provide cellular details about both [O2 ] and the production of reactive species. Myoglobin oxidation to the met state by NO/ROS is a known sensor with absorbance changes in the visible range. We previously employed Förster resonance energy transfer to read out the deoxygenation/oxygenation of myoglobin, creating the subcellular [O2 ] sensor Myoglobin-mCherry. We now add the fluorescent protein EYFP to this sensor to create a novel probe that senses both met formation, a proxy for ROS/NO exposure, and [O2 ]. Since both proteins are present in the construct, it can also relieve users from the need to measure fluorescence lifetime, making [O2 ] sensing available to a wider group of laboratories.
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Affiliation(s)
- Rozhin Penjweini
- Laboratory of Advanced Microscopy and Biophotonics, National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health (NIH), Bethesda, MD 20892-1412
| | - Branden Roarke
- Laboratory of Advanced Microscopy and Biophotonics, National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health (NIH), Bethesda, MD 20892-1412
| | - Greg Alspaugh
- Laboratory of Advanced Microscopy and Biophotonics, National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health (NIH), Bethesda, MD 20892-1412
| | - Katie A. Link
- Laboratory of Advanced Microscopy and Biophotonics, National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health (NIH), Bethesda, MD 20892-1412
| | - Alessio Andreoni
- Laboratory of Advanced Microscopy and Biophotonics, National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health (NIH), Bethesda, MD 20892-1412
- Laboratory of Optical Neurophysiology, Department of Biochemistry and Molecular Medicine, University of California Davis, Tupper Hall, Davis, CA 95616
| | - Mateus P. Mori
- Laboratory of Cardiovascular and Cancer Genetics, NHLBI, NIH, Bethesda, MD 20892-1412
| | - Paul M. Hwang
- Laboratory of Cardiovascular and Cancer Genetics, NHLBI, NIH, Bethesda, MD 20892-1412
| | - Dan L. Sackett
- Cytoskeletal Dynamics Group, Division of Basic and Translational Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda MD, 20892-0924
| | - Jay R. Knutson
- Laboratory of Advanced Microscopy and Biophotonics, National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health (NIH), Bethesda, MD 20892-1412
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17
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Abstract
FLASH radiotherapy is a novel technique that has been shown in numerous preclinical in vivo studies to have the potential to be the next important improvement in cancer treatment. However, the biological mechanisms responsible for the selective FLASH sparing effect of normal tissues are not yet known. An optimal translation of FLASH radiotherapy into the clinic would require a good understanding of the specific beam parameters that induces a FLASH effect, environmental conditions affecting the response, and the radiobiological mechanisms involved. Even though the FLASH effect has generally been considered as an in vivo effect, studies finding these answers would be difficult and ethically challenging to carry out solely in animals. Hence, suitable in vitro studies aimed towards finding these answers are needed. In this review, we describe and summarise several in vitro assays that have been used or could be used to finally elucidate the mechanisms behind the FLASH effect.
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18
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Chen YI, Chang YJ, Liao SC, Nguyen TD, Yang J, Kuo YA, Hong S, Liu YL, Rylander HG, Santacruz SR, Yankeelov TE, Yeh HC. Generative adversarial network enables rapid and robust fluorescence lifetime image analysis in live cells. Commun Biol 2022; 5:18. [PMID: 35017629 PMCID: PMC8752789 DOI: 10.1038/s42003-021-02938-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 11/24/2021] [Indexed: 11/09/2022] Open
Abstract
Fluorescence lifetime imaging microscopy (FLIM) is a powerful tool to quantify molecular compositions and study molecular states in complex cellular environment as the lifetime readings are not biased by fluorophore concentration or excitation power. However, the current methods to generate FLIM images are either computationally intensive or unreliable when the number of photons acquired at each pixel is low. Here we introduce a new deep learning-based method termed flimGANE (fluorescence lifetime imaging based on Generative Adversarial Network Estimation) that can rapidly generate accurate and high-quality FLIM images even in the photon-starved conditions. We demonstrated our model is up to 2,800 times faster than the gold standard time-domain maximum likelihood estimation (TD_MLE) and that flimGANE provides a more accurate analysis of low-photon-count histograms in barcode identification, cellular structure visualization, Förster resonance energy transfer characterization, and metabolic state analysis in live cells. With its advantages in speed and reliability, flimGANE is particularly useful in fundamental biological research and clinical applications, where high-speed analysis is critical.
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Affiliation(s)
- Yuan-I Chen
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Yin-Jui Chang
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Shih-Chu Liao
- ISS, Inc., 1602 Newton Drive, Champaign, IL, 61822, USA
| | - Trung Duc Nguyen
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Jianchen Yang
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Yu-An Kuo
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Soonwoo Hong
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Yen-Liang Liu
- Master Program for Biomedical Engineering, China Medical University, Taichung, 406040, Taiwan
- Research Center for Cancer Biology, China Medical University, Taichung, 406040, Taiwan
| | - H Grady Rylander
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Samantha R Santacruz
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
- Institute for Neuroscience, The University of Texas at Austin, Austin, TX, 78712, USA
- Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Thomas E Yankeelov
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
- Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, TX, 78712, USA
- Department of Diagnostic Medicine, The University of Texas at Austin, Austin, TX, 78712, USA
- Department of Oncology, The University of Texas at Austin, Austin, TX, 78712, USA
- Livestrong Cancer Institutes, The University of Texas at Austin, Austin, TX, 78712, USA
- Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Hsin-Chih Yeh
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA.
- Texas Materials Institute, The University of Texas at Austin, Austin, TX, 78712, USA.
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19
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Penjweini R, Mori MP, Hwang PM, Sackett DL, Knutson JR. Fluorescence lifetime imaging of metMyoglobin formation due to nitric oxide stress. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2022; 11965:119650H. [PMID: 35463920 PMCID: PMC9022600 DOI: 10.1117/12.2608888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Myoglobin is a protein that is expressed quite unevenly among different cell types. Nevertheless, it has been widely acknowledged that the Fe3+ state of myoglobin, metmyoglobin (metMb) has a broad functional role in metabolism, oxidative/nitrative regulation and gene networks. Accordingly, real-time monitoring of oxygenated, deoxygenated and metMb proportions- or, more broadly, of the mechanisms by which metMb is formed, presents a promising line of research. We had previously introduced a Förster resonance energy transfer (FRET) method to read out the deoxygenation/oxygenation states of myoglobin, by creating the targetable oxygen (O2) sensor Myoglobin-mCherry. In this sensor, changes in myoglobin absorbance features that occur with lost O2 occupancy -or upon metMb production- control the FRET rate from the fluorescent protein to myoglobin. When O2 is bound, mCherry fluorescence is only slightly quenched, but if either O2 is released or met is produced, FRET will increase- and this rate competing with emission reduces both emission yield and lifetime. Nitric oxide (NO) is an important signal (but also a toxic molecule) that can oxidize myoglobin to metMb with absorbance increases in the red visible range. mCherry thus senses both met and deoxygenated myoglobin, which cannot be easily separated at hypoxia. In order to dissect this, we treat cells with NO and investigate how the Myoglobin-mCherry lifetime is affected by generating metMb. More discriminatory power is then achieved when the fluorescent protein EYFP is added to Myoglobin-mCherry, creating a sandwich probe whose lifetime can selectively respond to metMb while being indifferent to O2 occupancy.
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Affiliation(s)
- Rozhin Penjweini
- Laboratory of Advanced Microscopy and Biophotonics, National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health (NIH), Building 10, Room 5D14, Bethesda, MD 20892-1412
| | - Mateus P Mori
- Laboratory of Cardiovascular and Cancer Genetics, NHLBI, NIH, Bethesda, MD 20892-1412
| | - Paul M Hwang
- Laboratory of Cardiovascular and Cancer Genetics, NHLBI, NIH, Bethesda, MD 20892-1412
| | - Dan L Sackett
- Cytoskeletal Dynamics Group, Division of Basic and Translational Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), NIH, Building 9, Room 1E129, Bethesda MD, 20892-0924
| | - Jay R Knutson
- Laboratory of Advanced Microscopy and Biophotonics, National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health (NIH), Building 10, Room 5D14, Bethesda, MD 20892-1412
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20
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Ouyang Y, Liu Y, Wang ZM, Liu Z, Wu M. FLIM as a Promising Tool for Cancer Diagnosis and Treatment Monitoring. NANO-MICRO LETTERS 2021; 13:133. [PMID: 34138374 PMCID: PMC8175610 DOI: 10.1007/s40820-021-00653-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Accepted: 04/19/2021] [Indexed: 05/04/2023]
Abstract
Fluorescence lifetime imaging microscopy (FLIM) has been rapidly developed over the past 30 years and widely applied in biomedical engineering. Recent progress in fluorophore-dyed probe design has widened the application prospects of fluorescence. Because fluorescence lifetime is sensitive to microenvironments and molecule alterations, FLIM is promising for the detection of pathological conditions. Current cancer-related FLIM applications can be divided into three main categories: (i) FLIM with autofluorescence molecules in or out of a cell, especially with reduced form of nicotinamide adenine dinucleotide, and flavin adenine dinucleotide for cellular metabolism research; (ii) FLIM with Förster resonance energy transfer for monitoring protein interactions; and (iii) FLIM with fluorophore-dyed probes for specific aberration detection. Advancements in nanomaterial production and efficient calculation systems, as well as novel cancer biomarker discoveries, have promoted FLIM optimization, offering more opportunities for medical research and applications to cancer diagnosis and treatment monitoring. This review summarizes cutting-edge researches from 2015 to 2020 on cancer-related FLIM applications and the potential of FLIM for future cancer diagnosis methods and anti-cancer therapy development. We also highlight current challenges and provide perspectives for further investigation.
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Affiliation(s)
- Yuzhen Ouyang
- Hunan Provincial Tumor Hospital and the Affiliated Tumor Hospital of Xiangya Medical School, Central South University, Changsha, 410013, Hunan, People's Republic of China
- School of Physics and Electronics, Hunan Key Laboratory for Super-Microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, 410083, Hunan, People's Republic of China
- The Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute, Central South University, Changsha, 410008, Hunan, People's Republic of China
| | - Yanping Liu
- School of Physics and Electronics, Hunan Key Laboratory for Super-Microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, 410083, Hunan, People's Republic of China.
- Shenzhen Research Institute of Central South University, A510a, Virtual University Building, Nanshan District, Southern District, High-tech Industrial Park, Yuehai Street, Shenzhen, People's Republic of China.
- State Key Laboratory of High-Performance Complex Manufacturing, Central South University, 932 South Lushan Road, Changsha, 410083, Hunan, People's Republic of China.
| | - Zhiming M Wang
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, 610054, Sichuan, People's Republic of China
| | - Zongwen Liu
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, NSW, 2006, Australia.
| | - Minghua Wu
- Hunan Provincial Tumor Hospital and the Affiliated Tumor Hospital of Xiangya Medical School, Central South University, Changsha, 410013, Hunan, People's Republic of China.
- School of Physics and Electronics, Hunan Key Laboratory for Super-Microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, 410083, Hunan, People's Republic of China.
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21
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Kalinina S, Freymueller C, Naskar N, von Einem B, Reess K, Sroka R, Rueck A. Bioenergetic Alterations of Metabolic Redox Coenzymes as NADH, FAD and FMN by Means of Fluorescence Lifetime Imaging Techniques. Int J Mol Sci 2021; 22:5952. [PMID: 34073057 PMCID: PMC8199032 DOI: 10.3390/ijms22115952] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 05/26/2021] [Accepted: 05/28/2021] [Indexed: 12/15/2022] Open
Abstract
Metabolic FLIM (fluorescence lifetime imaging) is used to image bioenergetic status in cells and tissue. Whereas an attribution of the fluorescence lifetime of coenzymes as an indicator for cell metabolism is mainly accepted, it is debated whether this is valid for the redox state of cells. In this regard, an innovative algorithm using the lifetime characteristics of nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) and flavin adenine dinucleotide (FAD) to calculate the fluorescence lifetime induced redox ratio (FLIRR) has been reported so far. We extended the FLIRR approach and present new results, which includes FLIM data of the various enzymes, such as NAD(P)H, FAD, as well as flavin mononucleotide (FMN). Our algorithm uses a two-exponential fitting procedure for the NAD(P)H autofluorescence and a three-exponential fit of the flavin signal. By extending the FLIRR approach, we introduced FLIRR1 as protein-bound NAD(P)H related to protein-bound FAD, FLIRR2 as protein-bound NAD(P)H related to free (unbound) FAD and FLIRR3 as protein-bound NAD(P)H related to protein-bound FMN. We compared the significance of extended FLIRR to the metabolic index, defined as the ratio of protein-bound NAD(P)H to free NAD(P)H. The statistically significant difference for tumor and normal cells was found to be highest for FLIRR1.
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Affiliation(s)
- Sviatlana Kalinina
- Core Facility Confocal and Multiphoton Microscopy, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany; (N.N.); (K.R.)
| | - Christian Freymueller
- Laser-Forschungslabor, LIFE Center, University Hospital, LMU Munich, Fraunhoferstrasse 20, 82152 Planegg, Germany; (C.F.); (R.S.)
- Department of Urology, University Hospital, LMU Munich, Marchioninistraße 15, 81377 Munich, Germany
| | - Nilanjon Naskar
- Core Facility Confocal and Multiphoton Microscopy, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany; (N.N.); (K.R.)
| | - Bjoern von Einem
- Zentrum Biomedizinische Forschung (ZBMF), Department of Neurology, Ulm University, Helmholtzstrasse, 8/1, 89081 Ulm, Germany;
| | - Kirsten Reess
- Core Facility Confocal and Multiphoton Microscopy, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany; (N.N.); (K.R.)
| | - Ronald Sroka
- Laser-Forschungslabor, LIFE Center, University Hospital, LMU Munich, Fraunhoferstrasse 20, 82152 Planegg, Germany; (C.F.); (R.S.)
- Department of Urology, University Hospital, LMU Munich, Marchioninistraße 15, 81377 Munich, Germany
| | - Angelika Rueck
- Core Facility Confocal and Multiphoton Microscopy, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany; (N.N.); (K.R.)
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22
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Schmitz R, Tweed K, Walsh C, Walsh AJ, Skala MC. Extracellular pH affects the fluorescence lifetimes of metabolic co-factors. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-210047LR. [PMID: 34032035 PMCID: PMC8144436 DOI: 10.1117/1.jbo.26.5.056502] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 05/11/2021] [Indexed: 06/12/2023]
Abstract
SIGNIFICANCE Autofluorescence measurements of the metabolic cofactors NADH and flavin adenine dinucleotide (FAD) provide a label-free method to quantify cellular metabolism. However, the effect of extracellular pH on flavin lifetimes is currently unknown. AIM To quantify the relationship between extracellular pH and the fluorescence lifetimes of FAD, flavin mononucleotide (FMN), and reduced nicotinamide adenine dinucleotide (phosphate) [NAD(P)H]. APPROACH Human breast cancer (BT474) and HeLa cells were placed in pH-adjusted media. Images of an intracellular pH indicator or endogenous fluorescence were acquired using two-photon fluorescence lifetime imaging. Fluorescence lifetimes of FAD and FMN in solutions were quantified over the same pH range. RESULTS The relationship between intracellular and extracellular pH was linear in both cell lines. Between extracellular pH 4 to 9, FAD mean lifetimes increased with increasing pH. NAD(P)H mean lifetimes decreased with increasing pH between extracellular pH 5 to 9. The relationship between NAD(P)H lifetime and extracellular pH differed between the two cell lines. Fluorescence lifetimes of FAD, FAD-cholesterol oxidase, and FMN solutions decreased, showed no trend, and showed no trend, respectively, with increasing pH. CONCLUSIONS Changes in endogenous fluorescence lifetimes with extracellular pH are mostly due to indirect changes within the cell rather than direct pH quenching of the endogenous molecules.
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Affiliation(s)
- Rebecca Schmitz
- Morgridge Institute for Research, Madison, Wisconsin, United States
- University of Wisconsin-Madison, Department of Biomedical Engineering, Madison, Wisconsin, United States
| | - Kelsey Tweed
- Morgridge Institute for Research, Madison, Wisconsin, United States
- University of Wisconsin-Madison, Department of Biomedical Engineering, Madison, Wisconsin, United States
| | - Christine Walsh
- Morgridge Institute for Research, Madison, Wisconsin, United States
| | - Alex J. Walsh
- Morgridge Institute for Research, Madison, Wisconsin, United States
- Texas A&M University, Department of Biomedical Engineering, College Station, Texas, United States
| | - Melissa C. Skala
- Morgridge Institute for Research, Madison, Wisconsin, United States
- University of Wisconsin-Madison, Department of Biomedical Engineering, Madison, Wisconsin, United States
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23
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André AC, Debande L, Marteyn BS. The selective advantage of facultative anaerobes relies on their unique ability to cope with changing oxygen levels during infection. Cell Microbiol 2021; 23:e13338. [PMID: 33813807 DOI: 10.1111/cmi.13338] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/18/2021] [Accepted: 03/19/2021] [Indexed: 12/19/2022]
Abstract
Bacteria, including those that are pathogenic, have been generally classified according to their ability to survive and grow in the presence or absence of oxygen: aerobic and anaerobic bacteria, respectively. Strict aerobes require oxygen to grow (e.g., Neisseria), and strict anaerobes grow exclusively without, and do not survive oxygen exposure (e.g., Clostridia); aerotolerant bacteria (e.g., Lactobacilli) are insensitive to oxygen exposure. Facultative anaerobes (e.g., E. coli) have the unique ability to grow in the presence or in the absence of oxygen and are thus well-adapted to these changing conditions, which may constitute an underestimated selective advantage for infection. In the WHO antibiotic-resistant 'priority pathogens' list, facultative anaerobes are overrepresented (8 among 12 listed pathogens), consistent with clinical studies performed in populations particularly susceptible to infectious diseases. Bacteria aerobic respiratory chain plays a central role in oxygen consumption, leading to the formation of hypoxic infectious sites (infectious hypoxia). Facultative anaerobes have developed a wide diversity of aerotolerance and anaerotolerance strategies in vivo. However, at a single cell level, the modulation of the intracellular oxygen level in host infected cells remains elusive and will be discussed in this review. In conclusion, the ability of facultative bacteria to evolve in the presence or the absence of oxygen is essential for their virulence strategy and constitute a selective advantage. TAKE AWAY: Most life-threatening pathogenic bacteria are facultative anaerobes. Only facultative anaerobes are aerotolerant, anaerotolerant and capable of consuming O2 . Facultative anaerobes induce and are well adapted to cellular hypoxia.
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Affiliation(s)
- Antonin C André
- Institut de Biologie Moléculaire et Cellulaire, Architecture et Réactivité de l'ARN, CNRS UPR9002, Université de Strasbourg, Strasbourg, France.,Université de Paris, Paris, France
| | - Lorine Debande
- Institut de Biologie Moléculaire et Cellulaire, Architecture et Réactivité de l'ARN, CNRS UPR9002, Université de Strasbourg, Strasbourg, France
| | - Benoit S Marteyn
- Institut de Biologie Moléculaire et Cellulaire, Architecture et Réactivité de l'ARN, CNRS UPR9002, Université de Strasbourg, Strasbourg, France.,University of Strasbourg Institute for Advanced Study (USIAS), Strasbourg, France.,Institut Pasteur, Unité de Pathogenèse des Infections Vasculaires, Paris Cedex 15, France
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24
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Dobrinskikh E, Sherlock LG, Orlicky DJ, Zheng L, De Dios R, Balasubramaniyan D, Sizemore T, Butler B, Wright CJ. The developing murine lung is susceptible to acetaminophen toxicity. Am J Physiol Lung Cell Mol Physiol 2021; 320:L969-L978. [PMID: 33759579 DOI: 10.1152/ajplung.00072.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Acetaminophen (n-acetyl-p-aminophenol, APAP) use in the neonatal intensive care unit is rapidly increasing. Although APAP-related hepatotoxicity is rarely reported in the neonatal literature, other end-organ toxicity can occur with toxic exposures. APAP-induced lung injury has been reported with toxic exposures in adults, but whether this occurs in the developing lung is unknown. Therefore, we tested whether toxic APAP exposures would injure the developing lung. Neonatal C57BL/6 mice (PN7, early alveolar stage of lung development) were exposed to a dose of APAP known to cause hepatotoxicity in adult mice (280 mg/kg, IP). This exposure induced significant lung injury in the absence of identifiable hepatic toxicity. This injury was associated with increased pulmonary expression of Cyp2e1, the xenobiotic enzyme responsible for the toxic conversion of APAP. Exposure was associated with increased pulmonary expression of antioxidant response genes and decreased pulmonary glutathione peroxidase activity level. Furthermore, we observed an increase in pulmonary expression of proinflammatory cytokines and chemokines. Lastly, we were able to demonstrate that this toxic APAP exposure was associated with a shift in pulmonary metabolism away from glycolysis with increased oxidative phosphorylation, a finding consistent with increased mitochondrial workload, potentially leading to mitochondrial toxicity. This previously unrecognized injury and metabolic implications highlight the need to look beyond the liver and evaluate both the acute and long-term pulmonary implications of APAP exposure in the perinatal period.
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Affiliation(s)
- Evgenia Dobrinskikh
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado.,Division of Pulmonary Sciences and Critical Care, Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado
| | - Laura G Sherlock
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | - David J Orlicky
- Department of Pathology, University of Colorado School of Medicine, Aurora, Colorado
| | - Lijun Zheng
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | - Robyn De Dios
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | - Durga Balasubramaniyan
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | - Thom Sizemore
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | - Brittany Butler
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | - Clyde J Wright
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
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25
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Warpsinski G, Smith MJ, Srivastava S, Keeley TP, Siow RCM, Fraser PA, Mann GE. Nrf2-regulated redox signaling in brain endothelial cells adapted to physiological oxygen levels: Consequences for sulforaphane mediated protection against hypoxia-reoxygenation. Redox Biol 2020; 37:101708. [PMID: 32949969 PMCID: PMC7502377 DOI: 10.1016/j.redox.2020.101708] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 08/21/2020] [Accepted: 08/27/2020] [Indexed: 02/06/2023] Open
Abstract
Ischemic stroke is associated with a surge in reactive oxygen species generation during reperfusion. The narrow therapeutic window for the delivery of intravenous thrombolysis and endovascular thrombectomy limits therapeutic options for patients. Thus, understanding the mechanisms regulating neurovascular redox defenses are key for improved clinical translation. Our previous studies in a rodent model of ischemic stroke established that activation of Nrf2 defense enzymes by pretreatment with sulforaphane (SFN) affords protection against neurovascular and neurological deficits. We here further investigate SFN mediated protection in mouse brain microvascular endothelial cells (bEnd.3) adapted long-term (5 days) to hyperoxic (18 kPa) and normoxic (5 kPa) O2 levels. Using an O2-sensitive phosphorescent nanoparticle probe, we measured an intracellular O2 level of 3.4 ± 0.1 kPa in bEnd 3 cells cultured under 5 kPa O2. Induction of HO-1 and GCLM by SFN (2.5 μM) was significantly attenuated in cells adapted to 5 kPa O2, despite nuclear accumulation of Nrf2. To simulate ischemic stroke, bEnd.3 cells were adapted to 18 or 5 kPa O2 and subjected to hypoxia (1 kPa O2, 1 h) and reoxygenation. In cells adapted to 18 kPa O2, reoxygenation induced free radical generation was abrogated by PEG-SOD and significantly attenuated by pretreatment with SFN (2.5 μM). Silencing Nrf2 transcription abrogated HO-1 and NQO1 induction and led to a significant increase in reoxygenation induced free radical generation. Notably, reoxygenation induced oxidative stress, assayed using the luminescence probe L-012 and fluorescence probes MitoSOX™ Red and FeRhoNox™-1, was diminished in cells cultured under 5 kPa O2, indicating an altered redox phenotype in brain microvascular cells adapted to physiological normoxia. As redox and other intracellular signaling pathways are critically affected by O2, the development of antioxidant therapies targeting the Keap1-Nrf2 defense pathway in treatment of ischemia-reperfusion injury in stroke, coronary and renal disease will require in vitro studies conducted under well-defined O2 levels. Physiological normoxia alters the redox phenotype of murine microvascular brain endothelial cells. Intracellular GSH levels are lower in bEnd.3 cells adapted to 5 kPa versus 18 kPa O2. Nrf2 activated HO-1 and GCLM expression is attenuated under physiological normoxia. Sulforaphane protects against reoxygenation induced reactive oxygen species generation via Nrf2.
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Affiliation(s)
- Gabriela Warpsinski
- King's British Heart Foundation Centre for Research Excellence, School of Cardiovascular Medicine & Sciences, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London, SE1 9NH, UK
| | - Matthew J Smith
- King's British Heart Foundation Centre for Research Excellence, School of Cardiovascular Medicine & Sciences, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London, SE1 9NH, UK
| | - Salil Srivastava
- King's British Heart Foundation Centre for Research Excellence, School of Cardiovascular Medicine & Sciences, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London, SE1 9NH, UK
| | - Thomas P Keeley
- King's British Heart Foundation Centre for Research Excellence, School of Cardiovascular Medicine & Sciences, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London, SE1 9NH, UK
| | - Richard C M Siow
- King's British Heart Foundation Centre for Research Excellence, School of Cardiovascular Medicine & Sciences, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London, SE1 9NH, UK
| | - Paul A Fraser
- King's British Heart Foundation Centre for Research Excellence, School of Cardiovascular Medicine & Sciences, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London, SE1 9NH, UK
| | - Giovanni E Mann
- King's British Heart Foundation Centre for Research Excellence, School of Cardiovascular Medicine & Sciences, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London, SE1 9NH, UK.
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