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Song A, Zhao N, Hilpert DC, Perry C, Baur JA, Wallace DC, Schaefer PM. Visualizing subcellular changes in the NAD(H) pool size versus redox state using fluorescence lifetime imaging microscopy of NADH. Commun Biol 2024; 7:428. [PMID: 38594590 PMCID: PMC11004000 DOI: 10.1038/s42003-024-06123-7] [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: 02/28/2023] [Accepted: 03/29/2024] [Indexed: 04/11/2024] Open
Abstract
NADH autofluorescence imaging is a promising approach for visualizing energy metabolism at the single-cell level. However, it is sensitive to the redox ratio and the total NAD(H) amount, which can change independently from each other, for example with aging. Here, we evaluate the potential of fluorescence lifetime imaging microscopy (FLIM) of NADH to differentiate between these modalities.We perform targeted modifications of the NAD(H) pool size and ratio in cells and mice and assess the impact on NADH FLIM. We show that NADH FLIM is sensitive to NAD(H) pool size, mimicking the effect of redox alterations. However, individual components of the fluorescence lifetime are differently impacted by redox versus pool size changes, allowing us to distinguish both modalities using only FLIM. Our results emphasize NADH FLIM's potential for evaluating cellular metabolism and relative NAD(H) levels with high spatial resolution, providing a crucial tool for our understanding of aging and metabolism.
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Affiliation(s)
- Angela Song
- Center for Mitochondrial and Epigenomic Medicine, Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Nicole Zhao
- Center for Mitochondrial and Epigenomic Medicine, Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Diana C Hilpert
- Department of Biological Sciences, Dartmouth College, Hanover, NH, USA
| | - Caroline Perry
- Department of Physiology and Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Joseph A Baur
- Department of Physiology and Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Douglas C Wallace
- Center for Mitochondrial and Epigenomic Medicine, Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, USA.
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| | - Patrick M Schaefer
- Center for Mitochondrial and Epigenomic Medicine, Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, USA.
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2
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Dwivedi SK, Arachchige DL, Waters M, Jaeger S, Mahmoud M, Olowolagba AM, Tucker DR, Geborkoff MR, Werner T, Luck RL, Godugu B, Liu H. Near-infrared Absorption and Emission Probes with Optimal Connection Bridges for Live Monitoring of NAD(P)H Dynamics in Living Systems. SENSORS AND ACTUATORS. B, CHEMICAL 2024; 402:135073. [PMID: 38559378 PMCID: PMC10976508 DOI: 10.1016/j.snb.2023.135073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Two NAD(P)H-biosensing probes consisting of 1,3,3-trimethyl-3H-indolium and 3-quinolinium acceptors, linked by thiophene, A, and 3,4-ethylenedioxythiophene, B, bridges are detailed. We synthesized probes C and D, replacing the thiophene connection in probe A with phenyl and 2,1,3-benzothiadiazole units, respectively. Probe E was prepared by substituting probe A's 3-quinolinium unit with a 1-methylquinoxalin-1-ium unit. Solutions are non-fluorescent but in the presence of NADH, exhibit near-infrared fluorescence at 742.1 nm and 727.2 nm for probes A and B, respectively, and generate absorbance signals at 690.6 nm and 685.9 nm. In contrast, probes C and D displayed pronounced interference from NADH fluorescence at 450 nm, whereas probe E exhibited minimal fluorescence alterations in response to NAD(P)H. Pre-treatment of A549 cells with glucose in the presence of probe A led to a significant increase in fluorescence intensity. Additionally, subjecting probe A to lactate and pyruvate molecules resulted in opposite changes in NAD(P)H levels, with lactate causing a substantial increase in fluorescence intensity, conversely, pyruvate resulted in a sharp decrease. Treatment of A549 cells with varying concentrations of the drugs cisplatin, gemcitabine, and camptothecin (5, 10, and 20 μM) led to a concentration-dependent increase in intracellular fluorescence intensity, signifying a rise in NAD(P)H levels. Finally, fruit fly larvae were treated with different concentrations of NADH and cisplatin illustrating applicability to live organisms. The results demonstrated a direct correlation between fluorescence intensity and the concentration of NADH and cisplatin, respectively, further confirming the efficacy of probe A in sensing changes in NAD(P)H levels within a whole organism.
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Affiliation(s)
- Sushil K Dwivedi
- Department of Chemistry, Michigan Technological University, Houghton, MI 49931
- Health Research Institute, Michigan Technological University, Houghton, MI 49931
| | - Dilka Liyana Arachchige
- Department of Chemistry, Michigan Technological University, Houghton, MI 49931
- Health Research Institute, Michigan Technological University, Houghton, MI 49931
| | - May Waters
- Department of Chemistry, Michigan Technological University, Houghton, MI 49931
- Health Research Institute, Michigan Technological University, Houghton, MI 49931
| | - Sophia Jaeger
- Department of Chemistry, Michigan Technological University, Houghton, MI 49931
- Health Research Institute, Michigan Technological University, Houghton, MI 49931
| | - Mohamed Mahmoud
- Department of Chemistry, Michigan Technological University, Houghton, MI 49931
- Health Research Institute, Michigan Technological University, Houghton, MI 49931
| | - Adenike Mary Olowolagba
- Department of Chemistry, Michigan Technological University, Houghton, MI 49931
- Health Research Institute, Michigan Technological University, Houghton, MI 49931
| | - Daniel R Tucker
- Department of Chemistry, Michigan Technological University, Houghton, MI 49931
| | - Micaela R Geborkoff
- Department of Biological Sciences, Michigan Technological University, Houghton, MI 49931
| | - Thomas Werner
- Department of Biological Sciences, Michigan Technological University, Houghton, MI 49931
| | - Rudy L Luck
- Department of Chemistry, Michigan Technological University, Houghton, MI 49931
| | - Bhaskar Godugu
- Department of Chemistry, University of Pittsburgh, Chevron Science Center, 219 Parkman Avenue, Pittsburgh, PA 15260
| | - Haiying Liu
- Department of Chemistry, Michigan Technological University, Houghton, MI 49931
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3
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Gong L, Liang J, Xie L, Zhang Z, Mei Z, Zhang W. Metabolic Reprogramming in Gliocyte Post-cerebral Ischemia/ Reperfusion: From Pathophysiology to Therapeutic Potential. Curr Neuropharmacol 2024; 22:1672-1696. [PMID: 38362904 DOI: 10.2174/1570159x22666240131121032] [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: 08/21/2023] [Revised: 12/08/2023] [Accepted: 12/13/2023] [Indexed: 02/17/2024] Open
Abstract
Ischemic stroke is a leading cause of disability and death worldwide. However, the clinical efficacy of recanalization therapy as a preferred option is significantly hindered by reperfusion injury. The transformation between different phenotypes of gliocytes is closely associated with cerebral ischemia/ reperfusion injury (CI/RI). Moreover, gliocyte polarization induces metabolic reprogramming, which refers to the shift in gliocyte phenotype and the overall transformation of the metabolic network to compensate for energy demand and building block requirements during CI/RI caused by hypoxia, energy deficiency, and oxidative stress. Within microglia, the pro-inflammatory phenotype exhibits upregulated glycolysis, pentose phosphate pathway, fatty acid synthesis, and glutamine synthesis, whereas the anti-inflammatory phenotype demonstrates enhanced mitochondrial oxidative phosphorylation and fatty acid oxidation. Reactive astrocytes display increased glycolysis but impaired glycogenolysis and reduced glutamate uptake after CI/RI. There is mounting evidence suggesting that manipulation of energy metabolism homeostasis can induce microglial cells and astrocytes to switch from neurotoxic to neuroprotective phenotypes. A comprehensive understanding of underlying mechanisms and manipulation strategies targeting metabolic pathways could potentially enable gliocytes to be reprogrammed toward beneficial functions while opening new therapeutic avenues for CI/RI treatment. This review provides an overview of current insights into metabolic reprogramming mechanisms in microglia and astrocytes within the pathophysiological context of CI/RI, along with potential pharmacological targets. Herein, we emphasize the potential of metabolic reprogramming of gliocytes as a therapeutic target for CI/RI and aim to offer a novel perspective in the treatment of CI/RI.
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Affiliation(s)
- Lipeng Gong
- Key Laboratory of Hunan Province for Integrated Traditional Chinese and Western Medicine on Prevention and Treatment of Cardio-Cerebral Diseases, College of Integrated Traditional Chinese Medicine and Western Medicine, Hunan University of Chinese Medicine, Changsha, Hunan 410208, China
| | - Junjie Liang
- Key Laboratory of Hunan Province for Integrated Traditional Chinese and Western Medicine on Prevention and Treatment of Cardio-Cerebral Diseases, College of Integrated Traditional Chinese Medicine and Western Medicine, Hunan University of Chinese Medicine, Changsha, Hunan 410208, China
| | - Letian Xie
- Key Laboratory of Hunan Province for Integrated Traditional Chinese and Western Medicine on Prevention and Treatment of Cardio-Cerebral Diseases, College of Integrated Traditional Chinese Medicine and Western Medicine, Hunan University of Chinese Medicine, Changsha, Hunan 410208, China
| | - Zhanwei Zhang
- Department of Neurosurgery, First Affiliated Hospital of Hunan University of Traditional Chinese Medicine, Changsha, Hunan 410007, China
| | - Zhigang Mei
- Key Laboratory of Hunan Province for Integrated Traditional Chinese and Western Medicine on Prevention and Treatment of Cardio-Cerebral Diseases, College of Integrated Traditional Chinese Medicine and Western Medicine, Hunan University of Chinese Medicine, Changsha, Hunan 410208, China
- Third-Grade Pharmacological Laboratory on Chinese Medicine Approved by State Administration of Traditional Chinese Medicine, College of Medicine and Health Sciences, China Three Gorges University, Yichang, Hubei 443002, China
| | - Wenli Zhang
- School of Pharmacy, Hunan University of Chinese Medicine, Changsha, Hunan 410208, China
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4
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Alterations in metabolic flux in migraine and the translational relevance. J Headache Pain 2022; 23:127. [PMID: 36175833 PMCID: PMC9523955 DOI: 10.1186/s10194-022-01494-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 09/10/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Migraine is a highly prevalent disorder with significant economical and personal burden. Despite the development of effective therapeutics, the causes which precipitate migraine attacks remain elusive. Clinical studies have highlighted altered metabolic flux and mitochondrial function in patients. In vivo animal experiments can allude to the metabolic mechanisms which may underlie migraine susceptibility. Understanding the translational relevance of these studies are important to identifying triggers, biomarkers and therapeutic targets in migraine. MAIN BODY Functional imaging studies have suggested that migraineurs feature metabolic syndrome, exhibiting hallmark features including upregulated oxidative phosphorylation yet depleted available free energy. Glucose hypometabolism is also evident in migraine patients and can lead to altered neuronal hyperexcitability such as the incidence of cortical spreading depression (CSD). The association between obesity and increased risk, frequency and worse prognosis of migraine also highlights lipid dysregulation in migraine pathology. Calcitonin gene related peptide (CGRP) has demonstrated an important role in sensitisation and nociception in headache, however its role in metabolic regulation in connection with migraine has not been thoroughly explored. Whether impaired metabolic function leads to increased release of peptides such as CGRP or excessive nociception leads to altered flux is yet unknown. CONCLUSION Migraine susceptibility may be underpinned by impaired metabolism resulting in depleted energy stores and altered neuronal function. This review discusses both clinical and in vivo studies which provide evidence of altered metabolic flux which contribute toward pathophysiology. It also reviews the translational relevance of animal studies in identifying targets of biomarker or therapeutic development.
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5
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Hilzenrat G, Gill ET, McArthur SL. Imaging approaches for monitoring three-dimensional cell and tissue culture systems. JOURNAL OF BIOPHOTONICS 2022; 15:e202100380. [PMID: 35357086 DOI: 10.1002/jbio.202100380] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 03/27/2022] [Accepted: 03/28/2022] [Indexed: 06/14/2023]
Abstract
The past decade has seen an increasing demand for more complex, reproducible and physiologically relevant tissue cultures that can mimic the structural and biological features of living tissues. Monitoring the viability, development and responses of such tissues in real-time are challenging due to the complexities of cell culture physical characteristics and the environments in which these cultures need to be maintained in. Significant developments in optics, such as optical manipulation, improved detection and data analysis, have made optical imaging a preferred choice for many three-dimensional (3D) cell culture monitoring applications. The aim of this review is to discuss the challenges associated with imaging and monitoring 3D tissues and cell culture, and highlight topical label-free imaging tools that enable bioengineers and biophysicists to non-invasively characterise engineered living tissues.
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Affiliation(s)
- Geva Hilzenrat
- Bioengineering Engineering Group, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, Victoria, Australia
- Biomedical Manufacturing, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Clayton, Victoria, Australia
| | - Emma T Gill
- Bioengineering Engineering Group, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, Victoria, Australia
- Biomedical Manufacturing, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Clayton, Victoria, Australia
| | - Sally L McArthur
- Bioengineering Engineering Group, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, Victoria, Australia
- Biomedical Manufacturing, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Clayton, Victoria, Australia
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6
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Razumtcev A, Li M, Rong J, Teng CC, Pfluegl C, Taylor LS, Simpson GJ. Label-Free Autofluorescence-Detected Mid-Infrared Photothermal Microscopy of Pharmaceutical Materials. Anal Chem 2022; 94:6512-6520. [PMID: 35446548 DOI: 10.1021/acs.analchem.1c05504] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Label-free autofluorescence-detected photothermal mid-IR (AF-PTIR) microscopy is demonstrated experimentally and applied to test the distribution of active pharmaceutical ingredients (APIs) in a mixture containing representative pharmaceutical excipients. Two-photon excited UV-fluorescence (TPE-UVF) supports autofluorescence of native aromatic moieties using visible-light optics. Thermal modulation of the fluorescence quantum yield serves to report on infrared absorption, enabling infrared spectroscopy in the fingerprint region with a spatial resolution dictated by fluorescence. AF-PTIR provides high selectivity and sensitivity in image contrast for aromatic APIs, complementing broadly applicable optical photothermal IR (O-PTIR) microscopy based on photothermal modulation of refractive index/scattering. Mapping the API distribution is critical in designing processes for powdered dosage form manufacturing, with high spatial variance potentially producing variability in both delivered dosage and product efficacy. The ubiquity of aromatic moieties within API candidates suggests the viability of AF-PTIR in combination with O-PTIR to improve the confidence of chemical classification in spatially heterogeneous dosage forms.
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Affiliation(s)
- Aleksandr Razumtcev
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Minghe Li
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Jiayue Rong
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Chu C Teng
- Pendar Technologies, 30 Spinelli Place, Cambridge, Massachusetts 02138, United States
| | - Christian Pfluegl
- Pendar Technologies, 30 Spinelli Place, Cambridge, Massachusetts 02138, United States
| | - Lynne S Taylor
- Physical and Industrial Pharmacy, Purdue University, West Lafayette, Indiana 47907, United States
| | - Garth J Simpson
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
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7
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Pham DL, Miller CR, Myers MS, Myers DM, Hansen LA, Nichols MG. Development and characterization of phasor-based analysis for FLIM to evaluate the metabolic and epigenetic impact of HER2 inhibition on squamous cell carcinoma cultures. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-210187R. [PMID: 34628733 PMCID: PMC8501457 DOI: 10.1117/1.jbo.26.10.106501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 09/14/2021] [Indexed: 06/13/2023]
Abstract
SIGNIFICANCE Deranged metabolism and dysregulated growth factor signaling are closely associated with abnormal levels of proliferation, a recognized hallmark in tumorigenesis. Fluorescence lifetime imaging microscopy (FLIM) of endogenous nicotinamide adenine dinucleotide (NADH), a key metabolic coenzyme, offers a non-invasive, diagnostic indicator of disease progression, and treatment response. The model-independent phasor analysis approach leverages FLIM to rapidly evaluate cancer metabolism in response to targeted therapy. AIM We combined lifetime and phasor FLIM analysis to evaluate the influence of human epidermal growth factor receptor 2 (HER2) inhibition, a prevalent cancer biomarker, on both nuclear and cytoplasmic NAD(P)H of two squamous cell carcinoma (SCC) cultures. While better established, the standard lifetime analysis approach is relatively slow and potentially subject to intrinsic fitting errors and model assumptions. Phasor FLIM analysis offers a rapid, model-independent alternative, but the sensitivity of the bound NAD(P)H fraction to growth factor signaling must also be firmly established. APPROACH Two SCC cultures with low- and high-HER2 expression, were imaged using multiphoton-excited NAD(P)H FLIM, with and without treatment of the HER2 inhibitor AG825. Cells were challenged with mitochondrial inhibition and uncoupling to investigate AG825's impact on the overall metabolic capacity. Phasor FLIM and lifetime fitting analyses were compared within nuclear and cytoplasmic compartments to investigate epigenetic and metabolic impacts of HER2 inhibition. RESULTS NAD(P)H fluorescence lifetime and bound fraction consistently decreased following HER2 inhibition in both cell lines. High-HER2 SCC74B cells displayed a more significant response than low-HER2 SCC74A in both techniques. HER2 inhibition induced greater changes in nuclear than cytoplasmic compartments, leading to an increase in NAD(P)H intensity and concentration. CONCLUSIONS The use of both, complementary FLIM analysis techniques together with quantitative fluorescence intensity revealed consistent, quantitative changes in NAD(P)H metabolism associated with inhibition of growth factor signaling in SCC cell lines. HER2 inhibition promoted increased reliance on oxidative phosphorylation in both cell lines.
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Affiliation(s)
- Dan L. Pham
- Creighton University, Department of Physics, Omaha, Nebraska, United States
| | | | - Molly S. Myers
- Creighton University, Department of Physics, Omaha, Nebraska, United States
| | - Dominick M. Myers
- Creighton University, Department of Biomedical Sciences, Omaha, Nebraska, United States
| | - Laura A. Hansen
- Creighton University, Department of Biomedical Sciences, Omaha, Nebraska, United States
| | - Michael G. Nichols
- Creighton University, Department of Physics, Omaha, Nebraska, United States
- Creighton University, Department of Biomedical Sciences, Omaha, Nebraska, United States
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8
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Gorbunova IA, Sasin ME, Golyshev DP, Semenov AA, Smolin AG, Beltukov YM, Vasyutinskii OS. Two-Photon Excited Fluorescence Dynamics in Enzyme-Bound NADH: the Heterogeneity of Fluorescence Decay Times and Anisotropic Relaxation. J Phys Chem B 2021; 125:9692-9707. [PMID: 34410128 DOI: 10.1021/acs.jpcb.1c04226] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The dynamics of polarized fluorescence in NADH in alcohol dehydrogenase (ADH) in buffer solution has been studied using the TCSPC spectroscopy. A global fit procedure was used for determination of the fluorescence parameters from experiment. The interpretation of the results obtained was supported by ab initio calculations of the NADH structure. A theoretical model was developed describing the polarized fluorescence decay in ADH-NADH complexes that considered several interaction scenarios. A comparative analysis of the polarization-insensitive fluorescence decay using multiexponential fitting models has been carried out. As shown, the origin of a significant enhancement of the decay time in the ADH-NADH complex can be attributed to the decrease of nonradiative relaxation rates in the nicotinamide ring in the conditions of the apolar binding site environment. The existence of a single decay time in the ADH-NADH complex in comparison with two decay times observed in free NADH was attributed to a single NADH unfolded conformation in the ADH binding site. Comparison of the experimental data with the theoretical model suggested the existence of an anisotropic relaxation time of about 1 ns that is related with the rotation of fluorescence transition dipole moment due to the rearrangement of the excited state NADH nuclear configuration.
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Affiliation(s)
| | - Maxim E Sasin
- Ioffe Institute, 26 Polytekhnicheskaya, St. Petersburg, 194021, Russia
| | - Dmitrii P Golyshev
- Ioffe Institute, 26 Polytekhnicheskaya, St. Petersburg, 194021, Russia.,Peter the Great St.Petersburg Polytechnic University, 29 Polytechnicheskaya, St. Petersburg, 195251, Russia
| | | | - Andrey G Smolin
- Ioffe Institute, 26 Polytekhnicheskaya, St. Petersburg, 194021, Russia
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9
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Heidelman M, Dhakal B, Gikunda M, Silva KPT, Risal L, Rodriguez AI, Abe F, Urayama P. Cellular NADH and NADPH Conformation as a Real-Time Fluorescence-Based Metabolic Indicator under Pressurized Conditions. Molecules 2021; 26:5020. [PMID: 34443607 PMCID: PMC8402201 DOI: 10.3390/molecules26165020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/15/2021] [Accepted: 08/16/2021] [Indexed: 11/25/2022] Open
Abstract
Cellular conformation of reduced pyridine nucleotides NADH and NADPH sensed using autofluorescence spectroscopy is presented as a real-time metabolic indicator under pressurized conditions. The approach provides information on the role of pressure in energy metabolism and antioxidant defense with applications in agriculture and food technologies. Here, we use spectral phasor analysis on UV-excited autofluorescence from Saccharomyces cerevisiae (baker's yeast) to assess the involvement of one or multiple NADH- or NADPH-linked pathways based on the presence of two-component spectral behavior during a metabolic response. To demonstrate metabolic monitoring under pressure, we first present the autofluorescence response to cyanide (a respiratory inhibitor) at 32 MPa. Although ambient and high-pressure responses remain similar, pressure itself also induces a response that is consistent with a change in cellular redox state and ROS production. Next, as an example of an autofluorescence response altered by pressurization, we investigate the response to ethanol at ambient, 12 MPa, and 30 MPa pressure. Ethanol (another respiratory inhibitor) and cyanide induce similar responses at ambient pressure. The onset of non-two-component spectral behavior upon pressurization suggests a change in the mechanism of ethanol action. Overall, results point to new avenues of investigation in piezophysiology by providing a way of visualizing metabolism and mitochondrial function under pressurized conditions.
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Affiliation(s)
- Martin Heidelman
- Department of Physics, Miami University, Oxford, OH 45056, USA; (M.H.); (B.D.); (M.G.); (K.P.T.S.); (L.R.); (A.I.R.)
| | - Bibek Dhakal
- Department of Physics, Miami University, Oxford, OH 45056, USA; (M.H.); (B.D.); (M.G.); (K.P.T.S.); (L.R.); (A.I.R.)
| | - Millicent Gikunda
- Department of Physics, Miami University, Oxford, OH 45056, USA; (M.H.); (B.D.); (M.G.); (K.P.T.S.); (L.R.); (A.I.R.)
| | - Kalinga Pavan Thushara Silva
- Department of Physics, Miami University, Oxford, OH 45056, USA; (M.H.); (B.D.); (M.G.); (K.P.T.S.); (L.R.); (A.I.R.)
| | - Laxmi Risal
- Department of Physics, Miami University, Oxford, OH 45056, USA; (M.H.); (B.D.); (M.G.); (K.P.T.S.); (L.R.); (A.I.R.)
| | - Andrew I. Rodriguez
- Department of Physics, Miami University, Oxford, OH 45056, USA; (M.H.); (B.D.); (M.G.); (K.P.T.S.); (L.R.); (A.I.R.)
| | - Fumiyoshi Abe
- Department of Chemistry and Biological Science, College of Science and Engineering, Aoyama Gakuin University, Sagamihara 252-5258, Japan;
| | - Paul Urayama
- Department of Physics, Miami University, Oxford, OH 45056, USA; (M.H.); (B.D.); (M.G.); (K.P.T.S.); (L.R.); (A.I.R.)
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10
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Sternisha SM, Mukherjee P, Alex A, Chaney EJ, Barkalifa R, Wan B, Lee JH, Rico-Jimenez J, Žurauskas M, Spillman DR, Sripada SA, Marjanovic M, Arp Z, Galosy SS, Bhanushali DS, Hood SR, Bose S, Boppart SA. Longitudinal monitoring of cell metabolism in biopharmaceutical production using label-free fluorescence lifetime imaging microscopy. Biotechnol J 2021; 16:e2000629. [PMID: 33951311 DOI: 10.1002/biot.202000629] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 04/12/2021] [Accepted: 04/28/2021] [Indexed: 11/11/2022]
Abstract
Chinese hamster ovary (CHO) cells are routinely used in the biopharmaceutical industry for production of therapeutic monoclonal antibodies (mAbs). Although multiple offline and time-consuming measurements of spent media composition and cell viability assays are used to monitor the status of culture in biopharmaceutical manufacturing, the day-to-day changes in the cellular microenvironment need further in-depth characterization. In this study, two-photon fluorescence lifetime imaging microscopy (2P-FLIM) was used as a tool to directly probe into the health of CHO cells from a bioreactor, exploiting the autofluorescence of intracellular nicotinamide adenine dinucleotide phosphate (NAD(P)H), an enzymatic cofactor that determines the redox state of the cells. A custom-built multimodal microscope with two-photon FLIM capability was utilized to monitor changes in NAD(P)H fluorescence for longitudinal characterization of a changing environment during cell culture processes. Three different cell lines were cultured in 0.5 L shake flasks and 3 L bioreactors. The resulting FLIM data revealed differences in the fluorescence lifetime parameters, which were an indicator of alterations in metabolic activity. In addition, a simple principal component analysis (PCA) of these optical parameters was able to identify differences in metabolic progression of two cell lines cultured in bioreactors. Improved understanding of cell health during antibody production processes can result in better streamlining of process development, thereby improving product titer and verification of scale-up. To our knowledge, this is the first study to use FLIM as a label-free measure of cellular metabolism in a biopharmaceutically relevant and clinically important CHO cell line.
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Affiliation(s)
- Shawn M Sternisha
- Biopharm Product Development, GlaxoSmithKline, King of Prussia, Pennsylvania, USA
| | - Prabuddha Mukherjee
- GSK Center for Optical Molecular Imaging, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Aneesh Alex
- GSK Center for Optical Molecular Imaging, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,In vitro/In vivo Translation, Research, GlaxoSmithKline, Collegeville, Pennsylvania, USA
| | - Eric J Chaney
- GSK Center for Optical Molecular Imaging, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Ronit Barkalifa
- GSK Center for Optical Molecular Imaging, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Boyong Wan
- Biopharm Product Development, GlaxoSmithKline, King of Prussia, Pennsylvania, USA
| | - Jang Hyuk Lee
- GSK Center for Optical Molecular Imaging, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Jose Rico-Jimenez
- GSK Center for Optical Molecular Imaging, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Mantas Žurauskas
- GSK Center for Optical Molecular Imaging, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Darold R Spillman
- GSK Center for Optical Molecular Imaging, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Sobhana A Sripada
- Biopharm Product Development, GlaxoSmithKline, King of Prussia, Pennsylvania, USA.,Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina, USA
| | - Marina Marjanovic
- GSK Center for Optical Molecular Imaging, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Zane Arp
- GSK Center for Optical Molecular Imaging, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Sybille S Galosy
- Biopharm Product Development, GlaxoSmithKline, King of Prussia, Pennsylvania, USA
| | | | - Steve R Hood
- GSK Center for Optical Molecular Imaging, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,GlaxoSmithKline Research and Development, Stevenage, Hertfordshire, UK
| | - Sayantan Bose
- Biopharm Product Development, GlaxoSmithKline, King of Prussia, Pennsylvania, USA
| | - Stephen A Boppart
- GSK Center for Optical Molecular Imaging, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
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11
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Tissue Imaging and Quantification Relying on Endogenous Contrast. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 3233:257-288. [PMID: 34053031 DOI: 10.1007/978-981-15-7627-0_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Cell-matrix interactions play an important role in regulating a variety of essential processes in multicellular organisms, and are closely associated with numerous diseases. Modified interactions have major effects upon key features of both cells and extracellular matrix (ECM), and a thorough understanding of changes in these features can lead to critically important insights of diseases as well as the identification of effective therapeutic targets. Here, we summarize recent advances in quantitative, optical imaging of cellular metabolism and ECM spatial organization using endogenous sources of contrast. Specifically, we focus on the two-photon excited fluorescence (TPEF) imaging of autofluorescent cellular coenzymes, NAD(P)H and FAD, for the extraction of metabolic information described by optical biomarkers including cellular redox state, NAD(P)H fluorescence lifetime, and mitochondrial clustering. We show representative applications in assessing adipose tissue function and detecting malignant lesions in human skin, and further demonstrate that a combination of these optical metrics can provide complementary insights into the underlying biological mechanisms. In addition, we review the development of quantitative analysis methods to extract spatial orientation and organization metrics of collagen fibers, a major ECM component, and demonstrate applications of these approaches in two and three dimensions in several diseases, including would healing, osteoarthritis and cancer, as well as assessments of matrix remodeling in hormone-regulated engineered breast tissues. Finally, we summarize this chapter and discuss important research directions that we expect will evolve in the near future.
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12
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Wang P, Hecht F, Ossato G, Tille S, Fraser SE, Junge JA. Complex wavelet filter improves FLIM phasors for photon starved imaging experiments. BIOMEDICAL OPTICS EXPRESS 2021; 12:3463-3473. [PMID: 34221672 PMCID: PMC8221945 DOI: 10.1364/boe.420953] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/22/2021] [Accepted: 03/30/2021] [Indexed: 05/11/2023]
Abstract
Fluorescence lifetime imaging microscopy (FLIM) with phasor analysis provides easy visualization and analysis of fluorophores' lifetimes which is valuable for multiple applications including metabolic imaging, STED imaging, FRET imaging and functional imaging. However, FLIM imaging typically suffers from low photon budgets, leading to unfavorable signal to noise ratios which in many cases prevent extraction of information from the data. Traditionally, median filters are applied in phasor analysis to tackle this problem. This unfortunately degrades high spatial frequency FLIM information in the phasor analysis. These high spatial frequency components are typically edges of features and puncta, which applies to membranes, mitochondria, granules and small organelles in a biological sample. To tackle this problem, we propose a filtering strategy with complex wavelet filtering and Anscombe transform for FLIM phasor analysis. This filtering strategy preserves fine structures and reports accurate lifetimes in photon starved FLIM imaging. Moreover, this filter outperforms median filters and makes FLIM imaging with lower laser power and faster imaging possible.
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Affiliation(s)
- P. Wang
- Translational Imaging Center, Dornsife School of Letters, Arts, and Sciences, University of Southern California, 1002 Childs Way, Los Angeles, CA 90089, USA
| | - F. Hecht
- Leica Microsystems CMS GmbH, Am Friedensplatz 3, Mannheim 68165, Germany
| | - G. Ossato
- Leica Microsystems CMS GmbH, Am Friedensplatz 3, Mannheim 68165, Germany
| | - S. Tille
- Leica Microsystems CMS GmbH, Am Friedensplatz 3, Mannheim 68165, Germany
| | - S. E. Fraser
- Translational Imaging Center, Dornsife School of Letters, Arts, and Sciences, University of Southern California, 1002 Childs Way, Los Angeles, CA 90089, USA
| | - J. A. Junge
- Translational Imaging Center, Dornsife School of Letters, Arts, and Sciences, University of Southern California, 1002 Childs Way, Los Angeles, CA 90089, USA
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13
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Chen H, Yu J, Men X, Zhang J, Ding Z, Jiang Y, Wu C, Chiu DT. Reversible Ratiometric NADH Sensing Using Semiconducting Polymer Dots. Angew Chem Int Ed Engl 2021; 60:12007-12012. [PMID: 33730372 PMCID: PMC8119375 DOI: 10.1002/anie.202100774] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Indexed: 11/10/2022]
Abstract
Reduced nicotinamide adenine dinucleotide (NADH) is a key coenzyme in living cells due to its role as an electron carrier in redox reactions, and its concentration is an important indicator of cell metabolic state. Abnormal NADH levels are associated with age-related metabolic diseases and neurodegenerative disorders, creating a demand for a simple, rapid analytical method for point-of-care NADH sensing. Here we develop a series of NADH-sensitive semiconducting polymer dots (Pdots) as nanoprobes for NADH measurement, and test their performance in vitro and in vivo. NADH sensing is based on electron transfer from semiconducting polymer chains in the Pdot to NADH upon UV excitation, quenching Pdot fluorescence emission. In polyfluorene-based Pdots, this mechanism resulted in an on-off NADH sensor; in DPA-CNPPV Pdots, UV excitation resulted in NADH-sensitive emission at two wavelengths, enabling ratiometric detection. Ratiometric NADH detection using DPA-CNPPV Pdots exhibits high sensitivity (3.1 μM limit of detection), excellent selectivity versus other analytes, reversibility, and a fast response (less than 5 s). We demonstrate applications of the ratiometric NADH-sensing Pdots including smartphone-based NADH imaging for point-of-care use.
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Affiliation(s)
- Haobin Chen
- Department of Chemistry and Bioengineering, University of Washington, Seattle, WA, 98195, USA
| | - Jiangbo Yu
- Department of Chemistry and Bioengineering, University of Washington, Seattle, WA, 98195, USA
| | - Xiaoxiao Men
- Department of Biomedical Engineering, Southern University Science and Technology, Shenzhen, Guangdong, 510855, China
| | - Jicheng Zhang
- Department of Chemistry and Bioengineering, University of Washington, Seattle, WA, 98195, USA
| | - Zhaoyang Ding
- Department of Chemistry and Bioengineering, University of Washington, Seattle, WA, 98195, USA
| | - Yifei Jiang
- Department of Chemistry and Bioengineering, University of Washington, Seattle, WA, 98195, USA
| | - Changfeng Wu
- Department of Biomedical Engineering, Southern University Science and Technology, Shenzhen, Guangdong, 510855, China
| | - Daniel T. Chiu
- Department of Chemistry and Bioengineering, University of Washington, Seattle, WA, 98195, USA
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14
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Grech O, Mollan SP, Wakerley BR, Fulton D, Lavery GG, Sinclair AJ. The Role of Metabolism in Migraine Pathophysiology and Susceptibility. Life (Basel) 2021; 11:415. [PMID: 34062792 PMCID: PMC8147354 DOI: 10.3390/life11050415] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 04/22/2021] [Accepted: 04/29/2021] [Indexed: 01/07/2023] Open
Abstract
Migraine is a highly prevalent and disabling primary headache disorder, however its pathophysiology remains unclear, hindering successful treatment. A number of key secondary headache disorders have headaches that mimic migraine. Evidence has suggested a role of mitochondrial dysfunction and an imbalance between energetic supply and demand that may contribute towards migraine susceptibility. Targeting these deficits with nutraceutical supplementation may provide an additional adjunctive therapy. Neuroimaging techniques have demonstrated a metabolic phenotype in migraine similar to mitochondrial cytopathies, featuring reduced free energy availability and increased metabolic rate. This is reciprocated in vivo when modelling a fundamental mechanism of migraine aura, cortical spreading depression. Trials assessing nutraceuticals successful in the treatment of mitochondrial cytopathies including magnesium, coenzyme q10 and riboflavin have also been conducted in migraine. Although promising results have emerged from nutraceutical trials in patients with levels of minerals or vitamins below a critical threshold, they are confounded by lacking control groups or cohorts that are not large enough to be representative. Energetic imbalance in migraine may be relevant in driving the tissue towards maximum metabolic capacity, leaving the brain lacking in free energy. Personalised medicine considering an individual's deficiencies may provide an approach to ameliorate migraine.
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Affiliation(s)
- Olivia Grech
- Metabolic Neurology, Institute of Metabolism and Systems Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK; (O.G.); (B.R.W.); (G.G.L.)
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TH, UK
| | - Susan P. Mollan
- Birmingham Neuro-Ophthalmology Unit, University Hospitals Birmingham NHS Foundation Trust, Birmingham B15 2TH, UK;
| | - Benjamin R. Wakerley
- Metabolic Neurology, Institute of Metabolism and Systems Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK; (O.G.); (B.R.W.); (G.G.L.)
- Department of Neurology, Queen Elizabeth Hospital, University Hospitals Birmingham NHS Trust, Birmingham B15 2TH, UK
| | - Daniel Fulton
- Institute of Inflammation and Ageing, University of Birmingham, Birmingham B15 2TT, UK;
| | - Gareth G. Lavery
- Metabolic Neurology, Institute of Metabolism and Systems Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK; (O.G.); (B.R.W.); (G.G.L.)
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TH, UK
| | - Alexandra J. Sinclair
- Metabolic Neurology, Institute of Metabolism and Systems Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK; (O.G.); (B.R.W.); (G.G.L.)
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TH, UK
- Department of Neurology, Queen Elizabeth Hospital, University Hospitals Birmingham NHS Trust, Birmingham B15 2TH, UK
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15
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Chen H, Yu J, Men X, Zhang J, Ding Z, Jiang Y, Wu C, Chiu DT. Reversible Ratiometric NADH Sensing Using Semiconducting Polymer Dots. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202100774] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Haobin Chen
- Department of Chemistry and Bioengineering University of Washington Seattle WA 98195 USA
| | - Jiangbo Yu
- Department of Chemistry and Bioengineering University of Washington Seattle WA 98195 USA
| | - Xiaoxiao Men
- Department of Biomedical Engineering Southern University Science and Technology Shenzhen Guangdong 510855 China
| | - Jicheng Zhang
- Department of Chemistry and Bioengineering University of Washington Seattle WA 98195 USA
| | - Zhaoyang Ding
- Department of Chemistry and Bioengineering University of Washington Seattle WA 98195 USA
| | - Yifei Jiang
- Department of Chemistry and Bioengineering University of Washington Seattle WA 98195 USA
| | - Changfeng Wu
- Department of Biomedical Engineering Southern University Science and Technology Shenzhen Guangdong 510855 China
| | - Daniel T. Chiu
- Department of Chemistry and Bioengineering University of Washington Seattle WA 98195 USA
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16
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Short AH, Al Aayedi N, Gaire M, Kreider M, Wong CK, Urayama P. Distinguishing chemically induced NADPH- and NADH-related metabolic responses using phasor analysis of UV-excited autofluorescence. RSC Adv 2021; 11:18757-18767. [PMID: 35478622 PMCID: PMC9033505 DOI: 10.1039/d1ra02648h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Accepted: 05/17/2021] [Indexed: 11/21/2022] Open
Abstract
NADPH and NADH are well known for their role in antioxidant defense and energy metabolism, respectively, however distinguishing their cellular autofluorescence signals is a challenge due to their nearly identical optical properties. Recent studies applying spectral phasor analysis to autofluorescence emission during chemically induced metabolic responses showed that two-component spectral behavior, i.e., spectral change acting as a superposition of two spectra, depended on whether one or multiple metabolic pathways were affected. Here, we use this property of spectral behavior to show that metabolic responses primarily involving NADPH or NADH can be distinguished. We start by observing that the cyanide-induced response at micro- and millimolar concentrations does not follow mutual two-component spectral behavior, suggesting their response mechanisms differ. While respiratory inhibition at millimolar cyanide concentration is well known and associated with the NADH pool, we find the autofluorescence response at micromolar cyanide concentration exhibits two-component spectral behavior with NADPH-linked EGCG- and peroxide-induced responses, suggesting an association with the NADPH pool. What emerges is a spectral phasor map useful for distinguishing cellular autofluorescence responses related to oxidative stress versus cellular respiration. A phasor approach was used to show that chemically induced cellular autofluorescence responses linked to NADPH and NADH pathways can be distinguished.![]()
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Affiliation(s)
| | | | - Madhu Gaire
- Department of Physics
- Miami University
- Oxford
- USA
| | - Max Kreider
- Department of Physics
- Miami University
- Oxford
- USA
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17
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Microglial metabolic flexibility supports immune surveillance of the brain parenchyma. Nat Commun 2020; 11:1559. [PMID: 32214088 PMCID: PMC7096448 DOI: 10.1038/s41467-020-15267-z] [Citation(s) in RCA: 135] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 02/27/2020] [Indexed: 02/07/2023] Open
Abstract
Microglia are highly motile cells that continuously monitor the brain environment and respond to damage-associated cues. While glucose is the main energy substrate used by neurons in the brain, the nutrients metabolized by microglia to support surveillance of the parenchyma remain unexplored. Here, we use fluorescence lifetime imaging of intracellular NAD(P)H and time-lapse two-photon imaging of microglial dynamics in vivo and in situ, to show unique aspects of the microglial metabolic signature in the brain. Microglia are metabolically flexible and can rapidly adapt to consume glutamine as an alternative metabolic fuel in the absence of glucose. During insulin-induced hypoglycemia in vivo or in aglycemia in acute brain slices, glutaminolysis supports the maintenance of microglial process motility and damage-sensing functions. This metabolic shift sustains mitochondrial metabolism and requires mTOR-dependent signaling. This remarkable plasticity allows microglia to maintain their critical surveillance and phagocytic roles, even after brain neuroenergetic homeostasis is compromised. Glucose is the main source of fuel in the brain. Here, the authors show that in the absence of glucose, glutamine is required for microglia to maintain their immune surveillance function.
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18
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Cao R, Wallrabe H, Periasamy A. Multiphoton FLIM imaging of NAD(P)H and FAD with one excitation wavelength. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:1-16. [PMID: 31920048 PMCID: PMC6951488 DOI: 10.1117/1.jbo.25.1.014510] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 12/12/2019] [Indexed: 05/07/2023]
Abstract
Two-photon fluorescence lifetime imaging microscopy (FLIM) is widely used to capture autofluorescence signals from cellular components to investigate dynamic physiological changes in live cells and tissues. Among these intrinsic fluorophores, nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) and flavin adenine dinucleotide (FAD)-essential coenzymes in cellular respiration-have been used as intrinsic fluorescent biomarkers for metabolic states in cancer and other pathologies. Traditional FLIM imaging for NAD(P)H, FAD, and in particular fluorescence lifetime redox ratio (FLIRR) requires a sequential multiwavelength excitation to avoid spectral bleed-through (SBT). This sequential imaging complicates image acquisition, may introduce motion artifacts, and reduce temporal resolution. Testing several two-photon excitation wavelengths in combination with optimized emission filters, we have proved a FLIM imaging protocol, allowing simultaneous image acquisition with a single 800-nm wavelength excitation for NADH and FAD with negligible SBT. As a first step, standard NADH and FAD single and mixed solutions were tested that mimic biological sample conditions. After these optimization steps, the assay was applied to two prostate cancer live cell lines: African-American (AA) and Caucasian-American (LNCaP), used in our previous publications. FLIRR result shows that, in cells, the 800-nm two-photon excitation wavelength is suitable for NADH and FAD FLIM imaging with negligible SBT. While NAD(P)H signals are decreased, sufficient photons are present for accurate lifetime fitting and FAD signals are measurably increased at lower laser power, compared with the common 890-nm excitation conditions. This single wavelength excitation allows a simplification of NADH and FAD FLIM imaging data analysis, decreasing the total imaging time. It also avoids motion artifacts and increases temporal resolution. This simplified assay will also make it more suitable to be applied in a clinical setting.
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Affiliation(s)
- Ruofan Cao
- University of Virginia, WM Keck Center for Cellular Imaging, Department of Biology, Charlottesville, Virginia, United States
| | - Horst Wallrabe
- University of Virginia, WM Keck Center for Cellular Imaging, Department of Biology, Charlottesville, Virginia, United States
| | - Ammasi Periasamy
- University of Virginia, WM Keck Center for Cellular Imaging, Department of Biology, Charlottesville, Virginia, United States
- University of Virginia, Department of Biomedical Engineering, Charlottesville, Virginia, United States
- Address all correspondence to Ammasi Periasamy, E-mail:
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19
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Ranjit S, Malacrida L, Stakic M, Gratton E. Determination of the metabolic index using the fluorescence lifetime of free and bound nicotinamide adenine dinucleotide using the phasor approach. JOURNAL OF BIOPHOTONICS 2019; 12:e201900156. [PMID: 31194290 PMCID: PMC6842045 DOI: 10.1002/jbio.201900156] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 06/09/2019] [Accepted: 06/12/2019] [Indexed: 05/05/2023]
Abstract
The fluorescence lifetime of nicotinamide adenine dinucleotide (NADH) is commonly used in conjunction with the phasor approach as a molecular biomarker to provide information on cellular metabolism of autofluorescence imaging of cells and tissue. However, in the phasor approach, the bound and free lifetime defining the phasor metabolic trajectory is a subject of debate. The fluorescence lifetime of NADH increases when bound to an enzyme, in contrast to the short multiexponential lifetime displayed by NADH in solution. The extent of fluorescence lifetime increase depends on the enzyme to which NADH is bound. With proper preparation of lactate dehydrogenase (LDH) using oxalic acid (OA) as an allosteric factor, bound NADH to LDH has a lifetime of 3.4 ns and is positioned on the universal semicircle of the phasor plot, inferring a monoexponential lifetime for this species. Surprisingly, measurements in the cellular environments with different metabolic states show a linear trajectory between free NADH at about 0.37 ns and bound NADH at 3.4 ns. These observations support that in a cellular environment, a 3.4 ns value could be used for bound NADH lifetime. The phasor analysis of many cell types shows a linear combination of fractional contributions of free and bound species NADH.
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Affiliation(s)
- Suman Ranjit
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, California
| | - Leonel Malacrida
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, California
- Departamento de Fisiopatología, Hospital de Clínicas, Universidad de la República, Montevideo, Uruguay
| | - Milka Stakic
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, California
| | - Enrico Gratton
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, California
- Corresponding author ()
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20
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York EM, Weilinger NL, LeDue JM, MacVicar BA. Green fluorescent protein emission obscures metabolic fluorescent lifetime imaging of NAD(P)H. BIOMEDICAL OPTICS EXPRESS 2019; 10:4381-4394. [PMID: 31565496 PMCID: PMC6757450 DOI: 10.1364/boe.10.004381] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 05/10/2019] [Accepted: 05/17/2019] [Indexed: 05/23/2023]
Abstract
Autofluorescence of endogenous molecules can provide valuable insights in both basic research and clinical applications. One such technique is fluorescence lifetime imaging (FLIM) of NAD(P)H, which serves as a correlate of glycolysis and electron transport chain rates in metabolically active tissue. A powerful advantage of NAD(P)H-FLIM is the ability to measure cell-specific metabolism within heterogeneous tissues. Cell-type specific identification is most commonly achieved with directed green fluorescent protein (GFP) expression. However, we demonstrate that NAD(P)H-FLIM should not be analyzed in GFP-expressing cells, as GFP molecules themselves emit photons in the blue spectrum with short fluorescence lifetimes when imaged using two-photon excitation at 750 nm. This is substantially different from the reported GFP emission wavelength and lifetime after two-photon excitation at 910 nm. These blue GFP photons are indistinguishable from free NAD(P)H by both emission spectra and fluorescence lifetime. Therefore, NAD(P)H-FLIM in GFP-expressing cells will lead to incorrect interpretations of metabolic rates, and thus, these techniques should not be combined.
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Affiliation(s)
- Elisa M York
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, British Columbia, Canada
| | - Nicholas L Weilinger
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, British Columbia, Canada
| | - Jeffrey M LeDue
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, British Columbia, Canada
| | - Brian A MacVicar
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, British Columbia, Canada
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21
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Loukanov A. Two-photon microscopy assessment of the overall energy metabolism alteration of amoeba in hypertonic environment. Microsc Res Tech 2019; 82:1728-1734. [PMID: 31283087 DOI: 10.1002/jemt.23338] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 05/23/2019] [Accepted: 06/24/2019] [Indexed: 01/20/2023]
Abstract
In this study, a two-photon fluorescence microscopic imaging technique is reported for assessment the effect of dynamic hypertonic environment on the overall energy metabolism alteration and adaptation of soil-living amoeba Dictyostelium discoideum. For that purpose the fluorescence intensity of mitochondrial reduced nicotinamide adenine dinucleotide (NADH) was monitored and quantified in order to evaluate the corresponded metabolic state of monolayer cultured cells. The two-photon excitation of NADH with 720 nm near infrared irradiation produced blue fluorescence emission with maximum wavelength centered at 460 nm. The benefits of reported noninvasive microscopic technique are the significantly less cellular damage and avoiding the excitation of other biomolecules except of NADH. It enabled to acquire data for NADH levels of the observed cells on agar plate specimen and hypertonic nutrition media in a Petri dish. The method demonstrated also good sensitivity, reproducibility and the obtained results revealed that D. discoideum species form aggregation in hypertonic environment within several minutes with aim to survive. The formed aggregate had amorphous shape and it consisted from dozen amoeba cells, which kept their NADH amount in constant level for few hours. The reported imaging method might be applicable in various studies for characterization of metabolic events and assessment of the cell energy balance in hypertonic environment.
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Affiliation(s)
- Alexandre Loukanov
- Division of Strategic Research and Development, Graduate School of Science and Engineering, Saitama University, Saitama, Japan.,Laboratory of Engineering NanoBiotechnology, Department of Engineering Geoecology, University of Mining and Geology "St. Ivan Rilski", Sofia, Bulgaria
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22
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Theurey P, Connolly NMC, Fortunati I, Basso E, Lauwen S, Ferrante C, Moreira Pinho C, Joselin A, Gioran A, Bano D, Park DS, Ankarcrona M, Pizzo P, Prehn JHM. Systems biology identifies preserved integrity but impaired metabolism of mitochondria due to a glycolytic defect in Alzheimer's disease neurons. Aging Cell 2019; 18:e12924. [PMID: 30793475 PMCID: PMC6516149 DOI: 10.1111/acel.12924] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 12/14/2018] [Accepted: 01/21/2019] [Indexed: 01/09/2023] Open
Abstract
Mitochondrial dysfunction is implicated in most neurodegenerative diseases, including Alzheimer's disease (AD). We here combined experimental and computational approaches to investigate mitochondrial health and bioenergetic function in neurons from a double transgenic animal model of AD (PS2APP/B6.152H). Experiments in primary cortical neurons demonstrated that AD neurons had reduced mitochondrial respiratory capacity. Interestingly, the computational model predicted that this mitochondrial bioenergetic phenotype could not be explained by any defect in the mitochondrial respiratory chain (RC), but could be closely resembled by a simulated impairment in the mitochondrial NADH flux. Further computational analysis predicted that such an impairment would reduce levels of mitochondrial NADH, both in the resting state and following pharmacological manipulation of the RC. To validate these predictions, we utilized fluorescence lifetime imaging microscopy (FLIM) and autofluorescence imaging and confirmed that transgenic AD neurons had reduced mitochondrial NAD(P)H levels at rest, and impaired power of mitochondrial NAD(P)H production. Of note, FLIM measurements also highlighted reduced cytosolic NAD(P)H in these cells, and extracellular acidification experiments showed an impaired glycolytic flux. The impaired glycolytic flux was identified to be responsible for the observed mitochondrial hypometabolism, since bypassing glycolysis with pyruvate restored mitochondrial health. This study highlights the benefits of a systems biology approach when investigating complex, nonintuitive molecular processes such as mitochondrial bioenergetics, and indicates that primary cortical neurons from a transgenic AD model have reduced glycolytic flux, leading to reduced cytosolic and mitochondrial NAD(P)H and reduced mitochondrial respiratory capacity.
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Affiliation(s)
- Pierre Theurey
- Department of Biomedical Sciences University of Padua Padua Italy
| | - Niamh M. C. Connolly
- Department of Physiology & Medical Physics Royal College of Surgeons in Ireland Dublin Ireland
| | | | - Emy Basso
- Department of Biomedical Sciences University of Padua Padua Italy
- Neuroscience Institute – Italian National Research Council (CNR) Padua Italy
| | - Susette Lauwen
- Department of Physiology & Medical Physics Royal College of Surgeons in Ireland Dublin Ireland
| | | | - Catarina Moreira Pinho
- Center for Alzheimer Research, Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society Karolinska Institutet Stockholm Sweden
| | - Alvin Joselin
- Brain & Mind Research Institute University of Ottawa Ottawa Ontario Canada
| | - Anna Gioran
- German Center for Neurodegenerative Diseases (DZNE) Bonn Germany
| | - Daniele Bano
- German Center for Neurodegenerative Diseases (DZNE) Bonn Germany
| | - David S. Park
- Brain & Mind Research Institute University of Ottawa Ottawa Ontario Canada
| | - Maria Ankarcrona
- Center for Alzheimer Research, Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society Karolinska Institutet Stockholm Sweden
| | - Paola Pizzo
- Department of Biomedical Sciences University of Padua Padua Italy
- Neuroscience Institute – Italian National Research Council (CNR) Padua Italy
| | - Jochen H. M. Prehn
- Department of Physiology & Medical Physics Royal College of Surgeons in Ireland Dublin Ireland
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23
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Chacko JV, Eliceiri KW. Autofluorescence lifetime imaging of cellular metabolism: Sensitivity toward cell density, pH, intracellular, and intercellular heterogeneity. Cytometry A 2019; 95:56-69. [PMID: 30296355 PMCID: PMC6329636 DOI: 10.1002/cyto.a.23603] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 08/14/2018] [Accepted: 08/20/2018] [Indexed: 12/14/2022]
Abstract
Autofluorescence imaging (AFI) has greatly accelerated in the last decade, way past its origins in detecting endogenous signals in biological tissues to identify differences between samples. There are many endogenous fluorescence sources of contrast but the most robust and widely utilized have been those associated with metabolism. The intrinsically fluorescent metabolic cofactors nicotinamide adenine dinucleotide (NAD+ /NADH) and flavin adenine dinucleotide (FAD/FADH2 ) have been utilized in a number of AFI applications including basic research, clinical, and pharmaceutical studies. Fluorescence lifetime imaging microscopy (FLIM) has emerged as one of the more powerful AFI tools for NADH and FAD characterization due to its unique ability to noninvasively detect metabolite bound and free states and quantitate cellular redox ratio. However, despite this widespread biological use, many standardization methods are still needed to extend FLIM-based AFI into a fully robust research and clinical diagnostic tools. FLIM is sensitive to a wide range of factors in the fluorophore microenvironment, and there are a number of analysis variables as well. To this end, there has been an emphasis on developing imaging standards and ways to make the image acquisition and analysis more consistent. However, biological conditions during FLIM-based AFI imaging are rarely considered as key sources of FLIM variability. Here, we present several experimental factors with supporting data of the cellular microenvironment such as confluency, pH, inter-/intracellular heterogeneity, and choice of cell line that need to be considered for accurate quantitative FLIM-based AFI measurement of cellular metabolism. © 2018 International Society for Advancement of Cytometry.
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Affiliation(s)
- Jenu V. Chacko
- Laboratory for Optical and Computational Instrumentation, University of Wisconsin at Madison, Madison WI, USA
| | - Kevin W. Eliceiri
- Laboratory for Optical and Computational Instrumentation, University of Wisconsin at Madison, Madison WI, USA
- Biomedical Engineering Department, University of Wisconsin at Madison, Madison WI, USA
- Morgridge Institute for Research, Madison WI, USA
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24
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Schaefer PM, Kalinina S, Rueck A, von Arnim CAF, von Einem B. NADH Autofluorescence-A Marker on its Way to Boost Bioenergetic Research. Cytometry A 2018; 95:34-46. [PMID: 30211978 DOI: 10.1002/cyto.a.23597] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 07/20/2018] [Accepted: 08/04/2018] [Indexed: 12/20/2022]
Abstract
More than 60 years ago, the idea was introduced that NADH autofluorescence could be used as a marker of cellular redox state and indirectly also of cellular energy metabolism. Fluorescence lifetime imaging microscopy of NADH autofluorescence offers a marker-free readout of the mitochondrial function of cells in their natural microenvironment and allows different pools of NADH to be distinguished within a cell. Despite its many advantages in terms of spatial resolution and in vivo applicability, this technique still requires improvement in order to be fully useful in bioenergetics research. In the present review, we give a summary of technical and biological challenges that have so far limited the spread of this powerful technology. To help overcome these challenges, we provide a comprehensible overview of biological applications of NADH imaging, along with a detailed summary of valid imaging approaches that may be used to tackle many biological questions. This review is meant to provide all scientists interested in bioenergetics with support on how to embed successfully NADH imaging in their research. © 2018 International Society for Advancement of Cytometry.
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Affiliation(s)
| | - Sviatlana Kalinina
- Core Facility Confocal and Multiphoton Microscopy, Ulm University, Ulm, Germany
| | - Angelika Rueck
- Core Facility Confocal and Multiphoton Microscopy, Ulm University, Ulm, Germany
| | - Christine A F von Arnim
- Department of Neurology, Ulm University, Ulm, Germany.,Clinic for Neurogeriatrics and Neurological Rehabilitation, University- and Rehabilitation Hospital Ulm, Ulm, Germany
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25
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Hartl BA, Ma HSW, Sridharan S, Hansen KS, Kent MS, Gorin F, Fragoso RC, Marcu L. Label-free fluorescence lifetime spectroscopy detects radiation-induced necrotic changes in live brain in real-time. BIOMEDICAL OPTICS EXPRESS 2018; 9:3559-3580. [PMID: 30338140 PMCID: PMC6191615 DOI: 10.1364/boe.9.003559] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 04/28/2018] [Accepted: 05/22/2018] [Indexed: 05/21/2023]
Abstract
Current clinical imaging modalities do not reliably identify brain tissue regions with necrosis following radiotherapy. This creates challenges for stereotaxic biopsies and surgical-decision making. Time-resolved fluorescence spectroscopy (TRFS) provides a means to rapidly identify necrotic tissue by its distinct autofluorescence signature resulting from tissue breakdown and altered metabolic profiles in regions with radiation damage. Studies conducted in a live animal model of radiation necrosis demonstrated that necrotic tissue is characterized by respective increases of 27% and 108% in average lifetime and redox ratio, when compared with healthy tissue. Moreover, radiation-damaged tissue not visible by MRI but confirmed by histopathology, was detected by TRFS. Current results demonstrate the ability of TRFS to identify radiation-damaged brain tissue in real-time and indicates its potential to assist with surgical guidance and MRI-guided biopsy procedures.
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Affiliation(s)
- Brad A. Hartl
- Department of Biomedical Engineering, University of California, Davis, CA 95616,
USA
| | - Htet S. W. Ma
- Department of Biomedical Engineering, University of California, Davis, CA 95616,
USA
| | - Shamira Sridharan
- Department of Biomedical Engineering, University of California, Davis, CA 95616,
USA
| | - Katherine S. Hansen
- Department of Surgical and Radiological Sciences, University of California Davis School of Veterinary Medicine, Davis, CA 95616,
USA
| | - Michael S. Kent
- Department of Surgical and Radiological Sciences, University of California Davis School of Veterinary Medicine, Davis, CA 95616,
USA
| | - Fredric Gorin
- Department of Neurology, University of California Davis School of Medicine, Sacramento, CA 95817,
USA
| | - Ruben C. Fragoso
- Department of Radiation Oncology, University of California Davis School of Medicine, Sacramento, CA 95817,
USA
| | - Laura Marcu
- Department of Biomedical Engineering, University of California, Davis, CA 95616,
USA
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26
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Evers M, Salma N, Osseiran S, Casper M, Birngruber R, Evans CL, Manstein D. Enhanced quantification of metabolic activity for individual adipocytes by label-free FLIM. Sci Rep 2018; 8:8757. [PMID: 29884881 PMCID: PMC5993796 DOI: 10.1038/s41598-018-27093-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 05/24/2018] [Indexed: 01/07/2023] Open
Abstract
Fluorescence lifetime imaging microscopy (FLIM) of intrinsic fluorophores such as nicotinamide adenine dinucleotide (NADH) allows for label-free quantification of metabolic activity of individual cells over time and in response to various stimuli, which is not feasible using traditional methods due to their destructive nature and lack of spatial information. This study uses FLIM to measure pharmacologically induced metabolic changes that occur during the browning of white fat. Adipocyte browning increases energy expenditure, making it a desirable prospect for treating obesity and related disorders. Expanding from the traditional two-lifetime model of NADH to a four-lifetime model using exponential fitting and phasor analysis of the fluorescence decay results in superior metabolic assessment compared to traditional FLIM analysis. The four lifetime components can also be mapped to specific cellular compartments to create a novel optical ratio that quantitatively reflects changes in mitochondrial and cytosolic NADH concentrations and binding states. This widely applicable approach constitutes a powerful tool for studies where monitoring cellular metabolism is of key interest.
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Affiliation(s)
- Michael Evers
- Cutaneous Biology Research Center, Department of Dermatology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA. .,Institute of Biomedical Optics, University of Lübeck, Lübeck, 23562, Germany.
| | - Nunciada Salma
- Cutaneous Biology Research Center, Department of Dermatology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA
| | - Sam Osseiran
- Wellman Center for Photomedicine, Department of Dermatology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA
| | - Malte Casper
- Cutaneous Biology Research Center, Department of Dermatology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA.,Institute of Biomedical Optics, University of Lübeck, Lübeck, 23562, Germany
| | - Reginald Birngruber
- Institute of Biomedical Optics, University of Lübeck, Lübeck, 23562, Germany
| | - Conor L Evans
- Wellman Center for Photomedicine, Department of Dermatology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA
| | - Dieter Manstein
- Cutaneous Biology Research Center, Department of Dermatology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA.
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27
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Protein-bound NAD(P)H Lifetime is Sensitive to Multiple Fates of Glucose Carbon. Sci Rep 2018; 8:5456. [PMID: 29615678 PMCID: PMC5883019 DOI: 10.1038/s41598-018-23691-x] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 03/19/2018] [Indexed: 12/12/2022] Open
Abstract
While NAD(P)H fluorescence lifetime imaging (FLIM) can detect changes in flux through the TCA cycle and electron transport chain (ETC), it remains unclear whether NAD(P)H FLIM is sensitive to other potential fates of glucose. Glucose carbon can be diverted from mitochondria by the pentose phosphate pathway (via glucose 6-phosphate dehydrogenase, G6PDH), lactate production (via lactate dehydrogenase, LDH), and rejection of carbon from the TCA cycle (via pyruvate dehydrogenase kinase, PDK), all of which can be upregulated in cancer cells. Here, we demonstrate that multiphoton NAD(P)H FLIM can be used to quantify the relative concentrations of recombinant LDH and malate dehydrogenase (MDH) in solution. In multiple epithelial cell lines, NAD(P)H FLIM was also sensitive to inhibition of LDH and PDK, as well as the directionality of LDH in cells forced to use pyruvate versus lactate as fuel sources. Among the parameters measurable by FLIM, only the lifetime of protein-bound NAD(P)H (τ2) was sensitive to these changes, in contrast to the optical redox ratio, mean NAD(P)H lifetime, free NAD(P)H lifetime, or the relative amount of free and protein-bound NAD(P)H. NAD(P)H τ2 offers the ability to non-invasively quantify diversions of carbon away from the TCA cycle/ETC, which may support mechanisms of drug resistance.
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28
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Liu Z, Pouli D, Alonzo CA, Varone A, Karaliota S, Quinn KP, Münger K, Karalis KP, Georgakoudi I. Mapping metabolic changes by noninvasive, multiparametric, high-resolution imaging using endogenous contrast. SCIENCE ADVANCES 2018; 4:eaap9302. [PMID: 29536043 PMCID: PMC5846284 DOI: 10.1126/sciadv.aap9302] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Monitoring subcellular functional and structural changes associated with metabolism is essential for understanding healthy tissue development and the progression of numerous diseases, including cancer, diabetes, and cardiovascular and neurodegenerative disorders. Unfortunately, established methods for this purpose either are destructive or require the use of exogenous agents. Recent work has highlighted the potential of endogenous two-photon excited fluorescence (TPEF) as a method to monitor subtle metabolic changes; however, mechanistic understanding of the connections between the detected optical signal and the underlying metabolic pathways has been lacking. We present a quantitative approach to detecting both functional and structural metabolic biomarkers noninvasively, relying on endogenous TPEF from two coenzymes, NADH (reduced form of nicotinamide adenine dinucleotide) and FAD (flavin adenine dinucleotide). We perform multiparametric analysis of three optical biomarkers within intact, living cells and three-dimensional tissues: cellular redox state, NADH fluorescence lifetime, and mitochondrial clustering. We monitor the biomarkers in cells and tissues subjected to metabolic perturbations that trigger changes in distinct metabolic processes, including glycolysis and glutaminolysis, extrinsic and intrinsic mitochondrial uncoupling, and fatty acid oxidation and synthesis. We demonstrate that these optical biomarkers provide complementary insights into the underlying biological mechanisms. Thus, when used in combination, these biomarkers can serve as a valuable tool for sensitive, label-free identification of changes in specific metabolic pathways and characterization of the heterogeneity of the elicited responses with single-cell resolution.
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Affiliation(s)
- Zhiyi Liu
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA
| | - Dimitra Pouli
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA
| | - Carlo A. Alonzo
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA
| | - Antonio Varone
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA
| | | | - Kyle P. Quinn
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR 72701, USA
| | - Karl Münger
- Developmental, Molecular and Chemical Biology, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, MA 02111, USA
| | - Katia P. Karalis
- Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Irene Georgakoudi
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA
- Corresponding author.
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29
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Maltas J, Palo D, Wong CK, Stefan S, O'Connor J, Al Aayedi N, Gaire M, Kinn D, Urayama P. A metabolic interpretation for the response of cellular autofluorescence to chemical perturbations assessed using spectral phasor analysis. RSC Adv 2018; 8:41526-41535. [PMID: 35559319 PMCID: PMC9092013 DOI: 10.1039/c8ra07691j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Accepted: 11/29/2018] [Indexed: 12/05/2022] Open
Abstract
Analytical approaches for sensing cellular NADH conformation from autofluorescence signals have significance because NADH is a metabolic indicator and endogenous biomarker. Recently, spectral detection of multiple cellular NADH forms during chemically-induced metabolic response was reported, however because NADH is solvatochromic and the spectral change is small, the possibility of a non-metabolic interpretation needs to be considered. Here we investigate the response of UV-excited autofluorescence to a range of well-known chemicals affecting fermentation, respiration, and oxidative-stress pathways in Saccharomyces cerevisiae. The two-component nature of the spectral response is assessed using phasor analysis. By considering a series of physically similar and dissimilar chemicals acting on multiple pathways, we show how the two-component nature of a spectral response is of metabolic origin, indicative of whether a single or several pathways have been affected. The two-component nature of the autofluorescence response is indicative of whether a single or several pathways are affected.![]()
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Affiliation(s)
- Jeff Maltas
- Department of Physics
- Miami University
- Oxford
- USA
| | - Dylan Palo
- Department of Physics
- Miami University
- Oxford
- USA
| | | | | | | | | | - Madhu Gaire
- Department of Physics
- Miami University
- Oxford
- USA
| | - Diana Kinn
- Department of Physics
- Miami University
- Oxford
- USA
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30
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Schaefer PM, Hilpert D, Niederschweiberer M, Neuhauser L, Kalinina S, Calzia E, Rueck A, von Einem B, von Arnim CAF. Mitochondrial matrix pH as a decisive factor in neurometabolic imaging. NEUROPHOTONICS 2017; 4:045004. [PMID: 29181426 PMCID: PMC5685807 DOI: 10.1117/1.nph.4.4.045004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 10/16/2017] [Indexed: 06/07/2023]
Abstract
Alterations of cellular bioenergetics are a common feature in most neurodegenerative disorders. However, there is a selective vulnerability of different brain regions, cell types, and even mitochondrial populations to these metabolic disturbances. Thus, the aim of our study was to establish and validate an in vivo metabolic imaging technique to screen for mitochondrial function on the subcellular level. Based on nicotinamide adenine dinucleotide (phosphate) fluorescence lifetime imaging microscopy [NAD(P)H FLIM], we performed a quantitative correlation to high-resolution respirometry. Thereby, we revealed mitochondrial matrix pH as a decisive factor in imaging NAD(P)H redox state. By combining both parameters, we illustrate a quantitative, high-resolution assessment of mitochondrial function in metabolically modified cells as well as in an amyloid precursor protein-overexpressing model of Alzheimer's disease. Our metabolic imaging technique provides the basis for dissecting mitochondrial deficits not only in a range of neurodegenerative diseases, shedding light onto bioenergetic failures of cells remaining in their metabolic microenvironment.
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Affiliation(s)
| | - Diana Hilpert
- Ulm University, Department of Neurology, Ulm, Germany
| | | | | | - Sviatlana Kalinina
- Ulm University, Core Facility Confocal and Multiphoton Microscopy, Ulm, Germany
| | - Enrico Calzia
- University Medical School, Institute of Anesthesiological Pathophysiology and Process Engineering, Ulm, Germany
| | - Angelika Rueck
- Ulm University, Core Facility Confocal and Multiphoton Microscopy, Ulm, Germany
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31
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Rehman AU, Anwer AG, Gosnell ME, Mahbub SB, Liu G, Goldys EM. Fluorescence quenching of free and bound NADH in HeLa cells determined by hyperspectral imaging and unmixing of cell autofluorescence. BIOMEDICAL OPTICS EXPRESS 2017; 8:1488-1498. [PMID: 28663844 PMCID: PMC5480559 DOI: 10.1364/boe.8.001488] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 01/12/2017] [Accepted: 02/06/2017] [Indexed: 05/06/2023]
Abstract
Carbonyl cyanide-p-trifluoro methoxyphenylhydrazone (FCCP) is a well-known mitochondrial uncoupling agent. We examined FCCP-induced fluorescence quenching of reduced nicotinamide adenine dinucleotide / nicotinamide adenine dinucleotide phosphate (NAD(P)H) in solution and in cultured HeLa cells in a wide range of FCCP concentrations from 50 to 1000µM. A non-invasive label-free method of hyperspectral imaging of cell autofluorescence combined with unsupervised unmixing was used to separately isolate the emissions of free and bound NAD(P)H from cell autofluorescence. Hyperspectral image analysis of FCCP-treated HeLa cells confirms that this agent selectively quenches fluorescence of free and bound NAD(P)H in a broad range of concentrations. This is confirmed by the measurements of average NAD/NADH and NADP/NADPH content in cells. FCCP quenching of free NAD(P)H in cells and in solution is found to be similar, but quenching of bound NAD(P)H in cells is attenuated compared to solution quenching possibly due to a contribution from the metabolic and/or antioxidant response in cells. Chemical quenching of NAD(P)H fluorescence by FCCP validates the results of unsupervised unmixing of cell autofluorescence.
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Affiliation(s)
- Aziz Ul Rehman
- ARC Centre of Excellence in Nanoscale Biophotonics, Macquarie University, Sydney, 2109, New South Wales, Australia
- Biophotonics Laboratory, National Institute of Lasers and Optronics, Lehtrar Road, Islamabad 45650, Pakistan
| | - Ayad G. Anwer
- ARC Centre of Excellence in Nanoscale Biophotonics, Macquarie University, Sydney, 2109, New South Wales, Australia
| | - Martin E. Gosnell
- ARC Centre of Excellence in Nanoscale Biophotonics, Macquarie University, Sydney, 2109, New South Wales, Australia
- Quantitative Pty Ltd, ABN 17 165 684 186, Australia
| | - Saabah B. Mahbub
- ARC Centre of Excellence in Nanoscale Biophotonics, Macquarie University, Sydney, 2109, New South Wales, Australia
| | - Guozhen Liu
- ARC Centre of Excellence in Nanoscale Biophotonics, Macquarie University, Sydney, 2109, New South Wales, Australia
- Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, China
| | - Ewa M. Goldys
- ARC Centre of Excellence in Nanoscale Biophotonics, Macquarie University, Sydney, 2109, New South Wales, Australia
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32
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Avci P, Freire F, Banvolgyi A, Mylonakis E, Wikonkal NM, Hamblin MR. Sodium ascorbate kills Candida albicans in vitro via iron-catalyzed Fenton reaction: importance of oxygenation and metabolism. Future Microbiol 2016; 11:1535-1547. [PMID: 27855492 DOI: 10.2217/fmb-2016-0063] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
AIM Ascorbate can inhibit growth and even decrease viability of various microbial species including Candida albicans. However the optimum conditions and the mechanism of action are unclear. Materials/methodology: Candida albicans shaken for 90 min in a buffered solution of ascorbate (90 mM) gave a 5-log reduction of cell viability, while there was no killing without shaking, in growth media with different carbon sources or at 4°C. Killing was inhibited by the iron chelator 2,2'-bipyridyl. Hydroxyphenyl fluorescein probe showed the intracellular generation of hydroxyl radicals. RESULTS/CONCLUSION Ascorbate-mediated killing of C. albicans depends on oxygenation and metabolism, involves iron-catalyzed generation of hydroxyl radicals via Fenton reaction and depletion of intracellular NADH. Ascorbate could serve as a component of a topical antifungal therapy.
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Affiliation(s)
- Pinar Avci
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Dermatology, Harvard Medical School, Boston, MA 02115, USA.,Department of Dermatology, Venerology & Dermato-Oncology, Semmelweis University, Budapest 1085, Hungary
| | - Fernanda Freire
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Biosciences & Oral Diagnosis, Institute of Science & Technology, Universidade Estadual Paulista (UNESP), São José dos Campos, São Paulo 12245-000, Brazil
| | - Andras Banvolgyi
- Department of Dermatology, Venerology & Dermato-Oncology, Semmelweis University, Budapest 1085, Hungary
| | - Eleftherios Mylonakis
- Infectious Diseases Division, Warren Alpert Medical School of Brown University, Rhode Island Hospital, Providence, RI 02912, USA
| | - Norbert M Wikonkal
- Department of Dermatology, Venerology & Dermato-Oncology, Semmelweis University, Budapest 1085, Hungary
| | - Michael R Hamblin
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Dermatology, Harvard Medical School, Boston, MA 02115, USA.,Harvard-MIT Division of Health Sciences & Technology, Cambridge, MA 02139, USA
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33
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Bilan DS, Belousov VV. Genetically encoded probes for NAD +/NADH monitoring. Free Radic Biol Med 2016; 100:32-42. [PMID: 27387770 DOI: 10.1016/j.freeradbiomed.2016.06.018] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 06/04/2016] [Accepted: 06/18/2016] [Indexed: 12/18/2022]
Abstract
NAD+ and NADH participate in many metabolic reactions. The NAD+/NADH ratio is an important parameter reflecting the general metabolic and redox state of different types of cells. For a long time, in situ and in vivo NAD+/NADH monitoring has been hampered by the lack of suitable tools. The recent development of genetically encoded indicators based on fluorescent proteins linked to specific nucleotide-binding domains has already helped to address this monitoring problem. In this review, we will focus on four available indicators: Peredox, Frex family probes, RexYFP and SoNar. Each indicator has advantages and limitations. We will also discuss the most important points that should be considered when selecting a suitable indicator for certain experimental conditions.
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Affiliation(s)
- Dmitry S Bilan
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia
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34
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Datta R, Heylman C, George SC, Gratton E. Label-free imaging of metabolism and oxidative stress in human induced pluripotent stem cell-derived cardiomyocytes. BIOMEDICAL OPTICS EXPRESS 2016; 7:1690-701. [PMID: 27231614 PMCID: PMC4871074 DOI: 10.1364/boe.7.001690] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 03/29/2016] [Accepted: 03/29/2016] [Indexed: 05/20/2023]
Abstract
In this work we demonstrate a label-free optical imaging technique to assess metabolic status and oxidative stress in human induced pluripotent stem cell-derived cardiomyocytes by two-photon fluorescence lifetime imaging of endogenous fluorophores. Our results show the sensitivity of this method to detect shifts in metabolism and oxidative stress in the cardiomyocytes upon pathological stimuli of hypoxia and cardiotoxic drugs. This non-invasive imaging technique could prove beneficial for drug development and screening, especially for in vitro cardiac models created from stem cell-derived cardiomyocytes and to study the pathogenesis of cardiac diseases and therapy.
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Affiliation(s)
- Rupsa Datta
- Laboratory for Fluorescence Dynamic, University of California, Biomedical Engineering, Irvine, California 92617, USA
| | - Christopher Heylman
- Laboratory for Fluorescence Dynamic, University of California, Biomedical Engineering, Irvine, California 92617, USA
| | - Steven C. George
- Washington University in St. Louis, Biomedical Engineering, St. Louis, Missouri, 63130, USA
| | - Enrico Gratton
- Laboratory for Fluorescence Dynamic, University of California, Biomedical Engineering, Irvine, California 92617, USA
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35
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Maltas J, Amer L, Long Z, Palo D, Oliva A, Folz J, Urayama P. Autofluorescence from NADH Conformations Associated with Different Metabolic Pathways Monitored Using Nanosecond-Gated Spectroscopy and Spectral Phasor Analysis. Anal Chem 2015; 87:5117-24. [PMID: 25919968 DOI: 10.1021/ac504386x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cellular NADH conformation is increasingly recognized as an endogenous optical biomarker and metabolic indicator. Recently, we reported a real-time approach for tracking metabolism on the basis of the quantification of UV-excited autofluorescence spectrum shape. Here, we use nanosecond-gated spectral acquisition, combined with spectrum-shape quantification, to monitor the long excited-state lifetime autofluorescence (usually associated with protein-bound NADH conformations) separately from the autofluorescence signal as a whole. We observe that the autofluorescence response induced by two NADH-oxidation inhibitors—cyanide and ethanol—are similar in Saccharomyces cerevisiae when monitored using time-integrated detection but easily distinguished using time-gated detection. Results are consistent with the observation of multiple NADH conformations as assessed using spectral phasor analysis. Further, because well-known oxidation inhibitors are used, changes in spectrum shape can be associated with NADH conformations involved in the different metabolic pathways, giving bioanalytic utility to the spectral responses.
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36
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Vidugiriene J, Leippe D, Sobol M, Vidugiris G, Zhou W, Meisenheimer P, Gautam P, Wennerberg K, Cali JJ. Bioluminescent cell-based NAD(P)/NAD(P)H assays for rapid dinucleotide measurement and inhibitor screening. Assay Drug Dev Technol 2015; 12:514-26. [PMID: 25506801 DOI: 10.1089/adt.2014.605] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Abstract The central role of nicotinamide adenine dinucleotides in cellular energy metabolism and signaling makes them important nodes that link the metabolic state of cells with energy homeostasis and gene regulation. In this study, we describe the implementation of cell-based bioluminescence assays for rapid and sensitive measurement of those important redox cofactors. We show that the sensitivity of the assays (limit of detection ∼0.5 nM) enables the selective detection of total amounts of nonphosphorylated or phosphorylated dinucleotides directly in cell lysates. The total amount of NAD+NADH or NADP+NADPH levels can be detected in as low as 300 or 600 cells/well, respectively. The signal remains linear up to 5,000 cells/well with the maximum signal-to-background ratios ranging from 100 to 200 for NAD+NADH and from 50 to 100 for NADP+NADPH detection. The assays are robust (Z' value >0.7) and the inhibitor response curves generated using a known NAD biosynthetic pathway inhibitor FK866 correlate well with the reported data. More importantly, by multiplexing the dinucleotide detection assays with a fluorescent nonmetabolic cell viability assay, we show that dinucleotide levels can be decreased dramatically (>80%) by FK866 treatment before changes in cell viability are detected. The utility of the assays to identify modulators of intracellular nicotinamide adenine dinucleotide levels was further confirmed using an oncology active compound library, where novel dinucleotide regulating compounds were identified. For example, the histone deacetylase inhibitor entinostat was a potent inhibitor of cellular nicotinamide adenine dinucleotides, whereas the selective estrogen receptor modulator raloxifene unexpectedly caused a twofold increase in cellular nicotinamide adenine dinucleotide levels.
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Horilova J, Cunderlikova B, Marcek Chorvatova A. Time- and spectrally resolved characteristics of flavin fluorescence in U87MG cancer cells in culture. JOURNAL OF BIOMEDICAL OPTICS 2015; 20:51017. [PMID: 25521208 DOI: 10.1117/1.jbo.20.5.051017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 11/11/2014] [Indexed: 06/04/2023]
Abstract
Early detection of cancer is crucial for the successful diagnostics of its presence and its subsequent treatment. To improve cancer detection, we tested the progressive multimodal optical imaging of U87MG cells in culture. A combination of steady-state spectroscopic methods with the time-resolved approach provides a new insight into the native metabolism when focused on endogenous tissue fluorescence. In this contribution, we evaluated the metabolic state of living U87MG cancer cells in culture by means of endogenous flavin fluorescence. Confocal microscopy and time-resolved fluorescence imaging were employed to gather spectrally and time-resolved images of the flavin fluorescence. We observed that flavin fluorescence in U87MG cells was predominantly localized outside the cell nucleus in mitochondria, while exhibiting a spectral maximum under 500 nm and fluorescence lifetimes under 1.4 ns, suggesting the presence of bound flavins. In some cells, flavin fluorescence was also detected inside the cell nuclei in the nucleoli, exhibiting longer fluorescence lifetimes and a red-shifted spectral maximum, pointing to the presence of free flavin. Extra-nuclear flavin fluorescence was diminished by 2-deoxyglucose, but failed to increase with 2,4-dinitrophenol, the uncoupler of oxidative phosphorylation, indicating that the cells use glycolysis, rather than oxidative phosphorylation for functioning. These gathered data are the first step toward monitoring the metabolic state of U87MG cancer cells.
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Affiliation(s)
- Julia Horilova
- International Laser Centre, Department of Biophotonics, Ilkovicova 3, Bratislava 841 04, SlovakiabPavol Jozef Safarik University, Department of Biophysics, Faculty of Science, Jesenna 5, Kosice 040 01, Slovakia
| | - Beata Cunderlikova
- International Laser Centre, Department of Biophotonics, Ilkovicova 3, Bratislava 841 04, SlovakiacComenius University, Institute of Medical Physics, Biophysics, Informatics and Telemedicine, Faculty of Medicine, Sasinkova 2, Bratislava 813 72, Slovakia
| | - Alzbeta Marcek Chorvatova
- International Laser Centre, Department of Biophotonics, Ilkovicova 3, Bratislava 841 04, SlovakiadUniversity of Ss. Cyril and Methodius, Department of Biotechnology, Faculty of Natural Sciences, Nám. J. Herdu 2, Trnava 917 01, Slovakia
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Zholudeva LV, Ward KG, Nichols MG, Smith HJ. Gentamicin differentially alters cellular metabolism of cochlear hair cells as revealed by NAD(P)H fluorescence lifetime imaging. JOURNAL OF BIOMEDICAL OPTICS 2015; 20:051032. [PMID: 25688541 PMCID: PMC4405084 DOI: 10.1117/1.jbo.20.5.051032] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 01/15/2015] [Indexed: 06/04/2023]
Abstract
Aminoglycoside antibiotics are implicated as culprits of hearing loss in more than 120,000 individuals annually. Research has shown that the sensory cells, but not supporting cells, of the cochlea are readily damaged and/or lost after use of such antibiotics. High-frequency outer hair cells (OHCs) show a greater sensitivity to antibiotics than high- and low-frequency inner hair cells (IHCs). We hypothesize that variations in mitochondrial metabolism account for differences in susceptibility. Fluorescence lifetime microscopy was used to quantify changes in NAD(P)H in sensory and supporting cells from explanted murine cochleae exposed to mitochondrial uncouplers, inhibitors, and an ototoxic antibiotic, gentamicin (GM). Changes in metabolic state resulted in a redistribution of NAD(P)H between subcellular fluorescence lifetime pools. Supporting cells had a significantly longer lifetime than sensory cells. Pretreatment with GM increased NAD(P)H intensity in high-frequency sensory cells, as well as the NAD(P)H lifetime within IHCs. GM specifically increased NAD(P)H concentration in high-frequency OHCs, but not in IHCs or pillar cells. Variations in NAD(P)H intensity in response to mitochondrial toxins and GM were greatest in high-frequency OHCs. These results demonstrate that GM rapidly alters mitochondrial metabolism, differentially modulates cell metabolism, and provides evidence that GM-induced changes in metabolism are significant and greatest in high-frequency OHCs.
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Affiliation(s)
- Lyandysha V. Zholudeva
- Drexel University, Department of Neurobiology and Anatomy, 2900 West Queen Lane, Philadelphia, Pennsylvania 19129, United States
| | - Kristina G. Ward
- Creighton University, Department of Physics, 2500 California Plaza, Omaha, Nebraska 68178, United States
| | - Michael G. Nichols
- Creighton University, Department of Physics, 2500 California Plaza, Omaha, Nebraska 68178, United States
- Creighton University, Department of Biomedical Sciences, 2500 California Plaza, Omaha, Nebraska 68178, United States
| | - Heather Jensen Smith
- Creighton University, Department of Biomedical Sciences, 2500 California Plaza, Omaha, Nebraska 68178, United States
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Dmitriev RI, Papkovsky DB. Intracellular probes for imaging oxygen concentration: how good are they? Methods Appl Fluoresc 2015; 3:034001. [DOI: 10.1088/2050-6120/3/3/034001] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Edmunds KJ, Gargiulo P. Imaging Approaches in Functional Assessment of Implantable Myogenic Biomaterials and Engineered Muscle Tissue. Eur J Transl Myol 2015; 25:4847. [PMID: 26913149 PMCID: PMC4749010 DOI: 10.4081/ejtm.2015.4847] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 01/21/2015] [Indexed: 12/13/2022] Open
Abstract
The fields of tissue engineering and regenerative medicine utilize implantable biomaterials and engineered tissues to regenerate damaged cells or replace lost tissues. There are distinct challenges in all facets of this research, but functional assessments and monitoring of such complex environments as muscle tissues present the current strategic priority. Many extant methods for addressing these questions result in the destruction or alteration of tissues or cell populations under investigation. Modern advances in non-invasive imaging modalities present opportunities to rethink some of the anachronistic methods, however, their standard employment may not be optimal when considering advancements in myology. New image analysis protocols and/or combinations of established modalities need to be addressed. This review focuses on efficacies and limitations of available imaging modalities to the functional assessment of implantable myogenic biomaterials and engineered muscle tissues.
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Affiliation(s)
- Kyle J. Edmunds
- Institute for Biomedical and Neural Engineering, University of Reykjavík
| | - Paolo Gargiulo
- Institute for Biomedical and Neural Engineering, University of Reykjavík
- University Hospital Landspítali, Reykjavík, Iceland
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Long Z, Maltas J, Zatt MC, Cheng J, Alquist EJ, Brest A, Urayama P. The real-time quantification of autofluorescence spectrum shape for the monitoring of mitochondrial metabolism. JOURNAL OF BIOPHOTONICS 2015; 8:247-257. [PMID: 24634364 DOI: 10.1002/jbio.201300207] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 02/14/2014] [Accepted: 02/18/2014] [Indexed: 06/03/2023]
Abstract
The cellular proportion of free and protein-bound NADH complexes is increasingly recognized as a metabolic indicator and biomarker. Because free and bound forms exhibit different fluorescence spectra, we consider whether autofluorescence shape sufficiently correlates with mitochondrial metabolism to be useful for monitoring in cellular suspensions. Several computational approaches for rapidly quantifying spectrum shape are used to detect Saccharomyces cereviseae response to oxygenation, and to the addition of mitochondrial functional modifiers and metabolic substrates. Observed changes appear consistent with previous studies probing free/protein-bound proportions, making this a potentially useful approach for the real-time monitoring of metabolism. (© 2015 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim).
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Affiliation(s)
- Zac Long
- Department of Physics, Miami University, Oxford, OH, USA
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Plotegher N, Stringari C, Jahid S, Veronesi M, Girotto S, Gratton E, Bubacco L. NADH fluorescence lifetime is an endogenous reporter of α-synuclein aggregation in live cells. FASEB J 2015; 29:2484-94. [PMID: 25713058 DOI: 10.1096/fj.14-260281] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 02/06/2015] [Indexed: 12/22/2022]
Abstract
α-Synuclein (aS) aggregation has been amply investigated for its involvement in Parkinson's disease because its amyloid fibrils are the main constituent of Lewy bodies, one of the hallmarks of the disease. aS aggregation was studied here in vitro and in cellular models to correlate aggregation products with toxicity mechanisms. Independent results published elsewhere suggested that aS overexpression and/or aggregation may impair cellular metabolism and cause mitochondrial damage. In this context, we report the characterization of changes in NADH fluorescence properties in vitro and in human embryonic kidney 293 cells upon aS aggregation. The application of the phasor approach to study NADH fluorescence lifetime and emission allowed us to identify changes that correlate with aS aggregation. In particular, the fraction of bound NADH, characterized by longer lifetimes in comparison to free NADH, is increased, and the maximum of the NADH emission is shifted toward shorter wavelengths in the presence of aggregating aS both in vitro and in cells. These data suggest that NADH binds to aggregated aS. NMR experiments in vitro substantiate such binding, which occurs during aggregation. NADH fluorescence is thus useful to detect aS aggregation and by extension the associated oxidative stress.
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Affiliation(s)
- Nicoletta Plotegher
- *Department of Biology, University of Padua, Padua, Italy; Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, Irvine, California, USA; and Department of Drug Discovery and Development, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Chiara Stringari
- *Department of Biology, University of Padua, Padua, Italy; Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, Irvine, California, USA; and Department of Drug Discovery and Development, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Sohail Jahid
- *Department of Biology, University of Padua, Padua, Italy; Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, Irvine, California, USA; and Department of Drug Discovery and Development, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Marina Veronesi
- *Department of Biology, University of Padua, Padua, Italy; Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, Irvine, California, USA; and Department of Drug Discovery and Development, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Stefania Girotto
- *Department of Biology, University of Padua, Padua, Italy; Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, Irvine, California, USA; and Department of Drug Discovery and Development, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Enrico Gratton
- *Department of Biology, University of Padua, Padua, Italy; Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, Irvine, California, USA; and Department of Drug Discovery and Development, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Luigi Bubacco
- *Department of Biology, University of Padua, Padua, Italy; Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, Irvine, California, USA; and Department of Drug Discovery and Development, Istituto Italiano di Tecnologia, Genoa, Italy
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