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Smith HE, Mackenzie AM, Seddon C, Mould R, Kalampouka I, Malakar P, Needham SR, Beis K, Bell JD, Nunn A, Botchway SW. The use of NADH anisotropy to investigate mitochondrial cristae alignment. Sci Rep 2024; 14:5980. [PMID: 38472304 DOI: 10.1038/s41598-024-55780-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 02/26/2024] [Indexed: 03/14/2024] Open
Abstract
Life may be expressed as the flow of electrons, protons, and other ions, resulting in large potential difference. It is also highly photo-sensitive, as a large proportion of the redox capable molecules it relies on are chromophoric. It is thus suggestive that a key organelle in eukaryotes, the mitochondrion, constantly adapt their morphology as part of the homeostatic process. Studying unstained in vivo nano-scale structure in live cells is technically very challenging. One option is to study a central electron carrier in metabolism, reduced nicotinamide adenine dinucleotide (NADH), which is fluorescent and mostly located within mitochondria. Using one and two-photon absorption (340-360 nm and 730 nm, respectively), fluorescence lifetime imaging and anisotropy spectroscopy of NADH in solution and in live cells, we show that mitochondria do indeed appear to be aligned and exhibit high anisotropy (asymmetric directionality). Aqueous solution of NADH showed an anisotropy of ~ 0.20 compared to fluorescein or coumarin of < 0.1 and 0.04 in water respectively and as expected for small organic molecules. The anisotropy of NADH also increased further to 0.30 in the presence of proteins and 0.42 in glycerol (restricted environment) following two-photon excitation, suggesting more ordered structures. Two-photon NADH fluorescence imaging of Michigan Cancer Foundation-7 (MCF7) also showed strong anisotropy of 0.25 to 0.45. NADH has a quantum yield of fluorescence of 2% compared to more than 40% for photoionisation (electron generation), when exposed to light at 360 nm and below. The consequence of such highly ordered and directional NADH patterns with respect to electron ejection upon ultra-violet (UV) excitation could be very informative-especially in relation to ascertaining the extent of quantum effects in biology, including electron and photonic cascade, communication and modulation of effects such as spin and tunnelling.
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Affiliation(s)
- Holly E Smith
- UKRI, STFC, Central Laser Facility, Rutherford Appleton Laboratory, Oxfordshire, OX11 0QX, UK
| | - Alasdair M Mackenzie
- UKRI, STFC, Central Laser Facility, Rutherford Appleton Laboratory, Oxfordshire, OX11 0QX, UK
| | - Chloe Seddon
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
- Rutherford Appleton Laboratory, Research Complex at Harwell, Didcot, Oxfordshire, OX11 0FA, UK
| | - Rhys Mould
- School of Life Sciences, Research Centre for Optimal Health, University of Westminster, London, W1W 6UW, UK
| | - Ifi Kalampouka
- School of Life Sciences, Research Centre for Optimal Health, University of Westminster, London, W1W 6UW, UK
| | - Partha Malakar
- UKRI, STFC, Central Laser Facility, Rutherford Appleton Laboratory, Oxfordshire, OX11 0QX, UK
| | - Sarah R Needham
- UKRI, STFC, Central Laser Facility, Rutherford Appleton Laboratory, Oxfordshire, OX11 0QX, UK
| | - Konstantinos Beis
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
- Rutherford Appleton Laboratory, Research Complex at Harwell, Didcot, Oxfordshire, OX11 0FA, UK
| | - Jimmy D Bell
- School of Life Sciences, Research Centre for Optimal Health, University of Westminster, London, W1W 6UW, UK
| | - Alistair Nunn
- School of Life Sciences, Research Centre for Optimal Health, University of Westminster, London, W1W 6UW, UK
| | - Stanley W Botchway
- UKRI, STFC, Central Laser Facility, Rutherford Appleton Laboratory, Oxfordshire, OX11 0QX, UK.
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2
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Li L, Hong S, Kang D, Huang X, Zhang S, Zhang Z, Zhou Y, Chen J. Two-photon imaging reveals histopathological changes in the gastric tumor microenvironment induced by neoadjuvant treatment. BIOMEDICAL OPTICS EXPRESS 2023; 14:5085-5096. [PMID: 37854573 PMCID: PMC10581806 DOI: 10.1364/boe.501519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 08/27/2023] [Accepted: 09/01/2023] [Indexed: 10/20/2023]
Abstract
There is a close association between tumor response and survival in gastric cancer patients after receiving neoadjuvant treatment. An accurate and rapid assessment of therapeutic efficacy would be helpful for subsequent treatments and individual prognosis. At present, pathological examination is the gold standard for evaluating treatment response, however, it requires additional staining and the process is tedious, labor-intensive, as well as time-consuming. Here, we introduce a label-free imaging technique, two-photon imaging, to evaluate histopathological changes induced by pre-operative therapy, with a focus on assessing tumor regression as well as stromal response. Imaging data show that two-photon imaging allows label-free, rapid visualization of various aspects of pathological alterations in tumor microenvironment such as fibrotic reaction, inflammatory cell infiltration, mucinous response, isolated residual tumor cells. Moreover, a semi-automatic image processing approach is developed to extract the collagen morphological features, and statistical results show that there are significant differences in collagen area, length, width, cross-link space between the gastric cancer tissues with and without treatment. With the advent of a portable, miniaturized two-photon imaging device, we have enough reason to believe that this technique will become as an important auxiliary diagnostic tool in assessing neoadjuvant treatment response and thereby tailoring the most appropriate therapy strategies for the patients.
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Affiliation(s)
- Lianhuang Li
- Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou 350007, China
| | - Shichai Hong
- Department of Gastric Surgery, Fujian Medical University Union Hospital, Fuzhou 350001, China
- Department of Vascular Surgery, Zhongshan Hospital (Xiamen), Fudan University, Xiamen 361015, China
| | - Deyong Kang
- Department of Pathology, Fujian Medical University Union Hospital, Fuzhou 350001, China
| | - Xingxin Huang
- Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou 350007, China
| | - Shichao Zhang
- Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou 350007, China
| | - Zhenlin Zhang
- Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou 350007, China
| | - Yongjian Zhou
- Department of Gastric Surgery, Fujian Medical University Union Hospital, Fuzhou 350001, China
| | - Jianxin Chen
- Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou 350007, China
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3
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Buckley DP, Migaud ME, Tanner JJ. Conformational Preferences of Pyridone Adenine Dinucleotides from Molecular Dynamics Simulations. Int J Mol Sci 2022; 23:11866. [PMID: 36233167 PMCID: PMC9570408 DOI: 10.3390/ijms231911866] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 09/23/2022] [Accepted: 10/01/2022] [Indexed: 11/25/2022] Open
Abstract
Pyridone adenine dinucleotides (ox-NADs) are redox inactive derivatives of the enzyme cofactor and substrate nicotinamide adenine dinucleotide (NAD) that have a carbonyl group at the C2, C4, or C6 positions of the nicotinamide ring. These aberrant cofactor analogs accumulate in cells under stress and are potential inhibitors of enzymes that use NAD(H). We studied the conformational landscape of ox-NADs in solution using molecular dynamics simulations. Compared to NAD+ and NADH, 2-ox-NAD and 4-ox-NAD have an enhanced propensity for adopting the anti conformation of the pyridone ribose group, whereas 6-ox-NAD exhibits greater syn potential. Consequently, 2-ox-NAD and 4-ox-NAD have increased preference for folding into compact conformations, whereas 6-ox-NAD is more extended. ox-NADs have distinctive preferences for the orientation of the pyridone amide group, which are driven by intramolecular hydrogen bonding and steric interactions. These conformational preferences are compared to those of protein-bound NAD(H). Our results may help in identifying enzymes targeted by ox-NADs.
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Affiliation(s)
- David P. Buckley
- Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA
| | - Marie E. Migaud
- Mitchell Cancer Institute, Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL 36604, USA
| | - John J. Tanner
- Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA
- Department of Chemistry, University of Missouri, Columbia, MO 65211, USA
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4
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Song F, Ou X, Chou TY, Liu J, Gao H, Zhang R, Huang X, Zhao Z, Sun J, Chen S, Lam JWY, Tang BZ. Oxygen Quenching-Resistant Nanoaggregates with Aggregation-Induced Delayed Fluorescence for Time-Resolved Mapping of Intracellular Microviscosity. ACS NANO 2022; 16:6176-6184. [PMID: 35318852 DOI: 10.1021/acsnano.1c11661] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Microviscosity is a fundamental parameter in the biophysics of life science and governs numerous cellular processes. Thus, the development of real-time quantitative monitoring of microviscosity inside cells is important. The traditional probes for detecting microviscosity via time-resolved luminescence imaging (TRLI) are generally disturbed by autofluorescence or surrounding oxygen in cells. Herein, we developed loose packing nanoaggregates with aggregation-induced delayed fluorescence (FKP-POA and FKP-PTA) and free from the effect of oxygen and autofluorescence for viscosity mapping via TRLI. The feasibility of FKP-PTA nanoparticles (NPs) for microviscosity mapping through TRLI was demonstrated by monitoring the variation of microviscosity inside HepG2 cancer cells, which demonstrated a value change from 14.9 cP to 216.9 cP during the apoptosis. This indicates that FKP-PTA NP can be used as a probe for cellular microviscosity mapping to help people to understand the physiologically dynamic microenvironment. The present results are expected to promote the advancement of diagnostic and therapeutic methods to cope with related diseases.
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Affiliation(s)
- Fengyan Song
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China
- Department of Chemical Biology, School of Life Science and Chemistry, Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China
| | - Xinwen Ou
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China
| | - Tsu Yu Chou
- Ming Wai Lau Centre for Reparative Medicine, Karolinska Institutet, Hong Kong 999077, China
| | - Junkai Liu
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China
| | - Hui Gao
- School of Aeronautic Science and Engineering, Beihang University, Beijing 100191, China
| | - Ruoyao Zhang
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China
- Institute of Engineering Medicine, Beijing Institute of Technology, Beijing 100081, China
| | - Xiaolin Huang
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China
- State Key Laboratory of Food Science and Technology and School of Food Science and Technology, Nanchang University, Nanchang 330047, P. R. China
| | - Zujin Zhao
- State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China
| | - Jianwei Sun
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China
| | - Sijie Chen
- Ming Wai Lau Centre for Reparative Medicine, Karolinska Institutet, Hong Kong 999077, China
| | - Jacky W Y Lam
- Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China
| | - Ben Zhong Tang
- School of Science and Engineering, Shenzhen Institute of Aggregate Science and Technology, The Chinese University of Hong Kong, Shenzhen, Guangdong 518172, China
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5
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Cao S, Li H, Liu Y, Zhang M, Wang M, Zhou Z, Chen J, Zhang S, Xu J, Knutson JR. Femtosecond Fluorescence Spectra of NADH in Solution: Ultrafast Solvation Dynamics. J Phys Chem B 2020; 124:771-776. [PMID: 31941277 PMCID: PMC7477843 DOI: 10.1021/acs.jpcb.9b10656] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The ultrafast solvation dynamics of reduced nicotinamide adenine dinucleotide (NADH) free in solution has been investigated, using both a femtosecond upconversion spectrophotofluorometer and a picosecond time-correlated single-photon counting (TCSPC) apparatus. The familiar time constant of solvent relaxation originating in "bulk water" was found to be ∼1.4 ps, revealing ultrafast solvent reorientation upon excitation. We also found a slower spectral relaxation process with an apparent time of 27 ps, suggesting there could either be dissociable "biological water" hydration sites on the surface of NADH or internal dielectric rearrangements of the flexible solvated molecule on that timescale. In contrast, the femtosecond fluorescence anisotropy measurement revealed that rotational diffusion happened on two different timescales (3.6 ps (local) and 141 ps (tumbling)); thus, any dielectric rearrangement scenario for the 27 ps relaxation must occur without significant chromophore oscillator rotation. The coexistence of quasi-static self quenching (QSSQ) with the slower relaxation is also discussed.
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Affiliation(s)
- Simin Cao
- State Key Laboratory of Precision Spectroscopy , East China Normal University , Shanghai 200062 , China
| | - Haoyang Li
- State Key Laboratory of Precision Spectroscopy , East China Normal University , Shanghai 200062 , China
| | - Yangyi Liu
- State Key Laboratory of Precision Spectroscopy , East China Normal University , Shanghai 200062 , China
| | - Mengjie Zhang
- State Key Laboratory of Precision Spectroscopy , East China Normal University , Shanghai 200062 , China
| | - Mengyu Wang
- State Key Laboratory of Precision Spectroscopy , East China Normal University , Shanghai 200062 , China
| | - Zhongneng Zhou
- State Key Laboratory of Precision Spectroscopy , East China Normal University , Shanghai 200062 , China
| | - Jinquan Chen
- State Key Laboratory of Precision Spectroscopy , East China Normal University , Shanghai 200062 , China
| | - Sanjun Zhang
- State Key Laboratory of Precision Spectroscopy , East China Normal University , Shanghai 200062 , China
| | - Jianhua Xu
- State Key Laboratory of Precision Spectroscopy , East China Normal University , Shanghai 200062 , China
| | - Jay R Knutson
- Laboratory for Advanced Microscopy and Biophotonics, National Heart, Lung and Blood Institute , National Institutes of Health , Bethesda , Maryland 20892 , United States
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6
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Cadena-Caicedo A, Gonzalez-Cano B, López-Arteaga R, Esturau-Escofet N, Peon J. Ultrafast Fluorescence Signals from β-Dihydronicotinamide Adenine Dinucleotide: Resonant Energy Transfer in the Folded and Unfolded Forms. J Phys Chem B 2020; 124:519-530. [PMID: 31876417 DOI: 10.1021/acs.jpcb.9b10012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
β-Dihydronicotinamide adenine dinucleotide (NADH) plays a critical role in biological redox processes. Inside the cell, NADH can be in a folded or an unfolded conformation, depending on the chemical environment that surrounds it. It is known that selective excitation of adenine in NADH can induce energy transfer events from this nucleotide to the reduced nicotinamide chromophore. From the anticipated time scales, this process must compete with adenine's internal conversion channel, which is known to occur in the sub-picosecond time scale. In this work, we studied the dynamics of the excited states of both chromophores in NADH through the time resolution of the spontaneous emission from both nucleotides. Through these experiments, we extend the knowledge about the competition between the different photophysical channels both in the folded and unfolded states. The study involved the folded and unfolded states of NADH by experiments in water and methanol solutions. Our femtosecond fluorescence results were complemented by the first nuclear magnetic resonance through space magnetization transfer measurements on NADH, which establish the solvent-dependent folded versus unfolded states. We determined the dynamics of the excited states by direct excitation of dihydronicotinamide at 380 nm and adenine at 266 nm. From this, we were able to measure for the folded state, a time constant of 90 fs for energy transfer. Additionally, we determined that even in what is referred to as an unfolded state in methanol, non-negligible excitation transfer events do take place. Spontaneous emission anisotropy measurements were used in order to confirm the presence of a minor energy transfer channel in the methanol solutions where the unfolded state dominates.
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Affiliation(s)
- Andrea Cadena-Caicedo
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior , Ciudad Universitaria , Ciudad de México 04510 , Mexico
| | - Beatriz Gonzalez-Cano
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior , Ciudad Universitaria , Ciudad de México 04510 , Mexico
| | - Rafael López-Arteaga
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior , Ciudad Universitaria , Ciudad de México 04510 , Mexico
| | - Nuria Esturau-Escofet
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior , Ciudad Universitaria , Ciudad de México 04510 , Mexico
| | - Jorge Peon
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior , Ciudad Universitaria , Ciudad de México 04510 , Mexico
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7
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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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8
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Chen E, Esquerra RM, Meléndez PA, Chandrasekaran SS, Kliger DS. Microviscosity in E. coli Cells from Time-Resolved Linear Dichroism Measurements. J Phys Chem B 2018; 122:11381-11389. [PMID: 30118225 DOI: 10.1021/acs.jpcb.8b07362] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A protein's folding or function depends on its mobility through the viscous environment that is defined by the presence of macromolecules throughout the cell. The relevant parameter for this mobility is microviscosity-the viscosity on a time and distance scale that is important for protein folding/function movements. A quasi-null, ultrasensitive time-resolved linear dichroism (TRLD) spectroscopy is proving to be a useful tool for measurements of viscosity on this scale, with previous in vitro studies reporting on the microviscosities of crowded environments mimicked by high concentrations of different macromolecules. This study reports the microviscosity experienced by myoglobin in the E. coli cell's heterogeneous cytoplasm by using TRLD to measure rotational diffusion times. The results show that photolyzed deoxyMb ensembles randomize through environment-dependent rotational diffusion with a lifetime of 34 ± 6 ns. This value corresponds to a microviscosity of 2.82 ± 0.42 cP, which is consistent with previous reports of cytoplasmic viscosity in E. coli. The results of these TRLD studies in E. coli (1) provide a measurement of myoglobin mobility in the cytoplasm, (2) taken together with in vitro TRLD studies yield new insights into the nature of the cytoplasmic environment in cells, and (3) demonstrate the feasibility of TRLD as a probe of intracellular viscosity.
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Affiliation(s)
- Eefei Chen
- Department of Chemistry and Biochemistry , University of California , Santa Cruz , California 95064 , United States
| | - Raymond M Esquerra
- Department of Chemistry and Biochemistry , San Francisco State University , San Francisco , California 94132 , United States
| | - Philipp A Meléndez
- Department of Chemistry and Biochemistry , San Francisco State University , San Francisco , California 94132 , United States
| | - Sita S Chandrasekaran
- Department of Chemistry and Biochemistry , San Francisco State University , San Francisco , California 94132 , United States
| | - David S Kliger
- Department of Chemistry and Biochemistry , University of California , Santa Cruz , California 95064 , United States
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9
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Blacker TS, Duchen MR. Investigating mitochondrial redox state using NADH and NADPH autofluorescence. Free Radic Biol Med 2016; 100:53-65. [PMID: 27519271 PMCID: PMC5145803 DOI: 10.1016/j.freeradbiomed.2016.08.010] [Citation(s) in RCA: 208] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 08/02/2016] [Accepted: 08/08/2016] [Indexed: 11/27/2022]
Abstract
The redox states of the NAD and NADP pyridine nucleotide pools play critical roles in defining the activity of energy producing pathways, in driving oxidative stress and in maintaining antioxidant defences. Broadly speaking, NAD is primarily engaged in regulating energy-producing catabolic processes, whilst NADP may be involved in both antioxidant defence and free radical generation. Defects in the balance of these pathways are associated with numerous diseases, from diabetes and neurodegenerative disease to heart disease and cancer. As such, a method to assess the abundance and redox state of these separate pools in living tissues would provide invaluable insight into the underlying pathophysiology. Experimentally, the intrinsic fluorescence of the reduced forms of both redox cofactors, NADH and NADPH, has been used for this purpose since the mid-twentieth century. In this review, we outline the modern implementation of these techniques for studying mitochondrial redox state in complex tissue preparations. As the fluorescence spectra of NADH and NADPH are indistinguishable, interpreting the signals resulting from their combined fluorescence, often labelled NAD(P)H, can be complex. We therefore discuss recent studies using fluorescence lifetime imaging microscopy (FLIM) which offer the potential to discriminate between the two separate pools. This technique provides increased metabolic information from cellular autofluorescence in biomedical investigations, offering biochemical insights into the changes in time-resolved NAD(P)H fluorescence signals observed in diseased tissues.
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Affiliation(s)
- Thomas S Blacker
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK; Department of Physics and Astronomy, University College London, London WC1E 6BT, UK
| | - Michael R Duchen
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
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10
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The phasor-FLIM fingerprints reveal shifts from OXPHOS to enhanced glycolysis in Huntington Disease. Sci Rep 2016; 6:34755. [PMID: 27713486 PMCID: PMC5054433 DOI: 10.1038/srep34755] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 09/15/2016] [Indexed: 01/21/2023] Open
Abstract
Huntington disease (HD) is an autosomal neurodegenerative disorder caused by the expansion of Polyglutamine (polyQ) in exon 1 of the Huntingtin protein. Glutamine repeats below 36 are considered normal while repeats above 40 lead to HD. Impairment in energy metabolism is a common trend in Huntington pathogenesis; however, this effect is not fully understood. Here, we used the phasor approach and Fluorescence Lifetime Imaging Microscopy (FLIM) to measure changes between free and bound fractions of NADH as a indirect measure of metabolic alteration in living cells. Using Phasor-FLIM, pixel maps of metabolic alteration in HEK293 cell lines and in transgenic Drosophila expressing expanded and unexpanded polyQ HTT exon1 in the eye disc were developed. We found a significant shift towards increased free NADH, indicating an increased glycolytic state for cells and tissues expressing the expanded polyQ compared to unexpanded control. In the nucleus, a further lifetime shift occurs towards higher free NADH suggesting a possible synergism between metabolic dysfunction and transcriptional regulation. Our results indicate that metabolic dysfunction in HD shifts to increased glycolysis leading to oxidative stress and cell death. This powerful label free method can be used to screen native HD tissue samples and for potential drug screening.
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11
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He S, Ye C, Sun Q, Leung CK, Qu JY. Label-free nonlinear optical imaging of mouse retina. BIOMEDICAL OPTICS EXPRESS 2015; 6:1055-66. [PMID: 25798325 PMCID: PMC4361420 DOI: 10.1364/boe.6.001055] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 02/14/2015] [Accepted: 02/16/2015] [Indexed: 05/18/2023]
Abstract
A nonlinear optical (NLO) microscopy system integrating stimulated Raman scattering (SRS), two-photon excited fluorescence (TPEF) and second-harmonic generation (SHG) was developed to image fresh mouse retinas. The morphological and functional details of various retinal layers were revealed by the endogenous NLO signals. Particularly, high resolution label-free imaging of retinal neurons and nerve fibers in the ganglion cell and nerve fiber layers was achieved by capturing endogenous SRS and TPEF signals. In addition, the spectral and temporal analysis of TPEF images allowed visualization of different fluorescent components in the retinal pigment epithelium (RPE). Fluorophores with short TPEF lifetime, such as A2E, can be differentiated from other long-lifetime components in the RPE. The NLO imaging method would provide important information for investigation of retinal ganglion cell degeneration and holds the potential to study the biochemical processes of visual cycle in the RPE.
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Affiliation(s)
- Sicong He
- Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong,
China
- Center of Systems Biology and Human Health, School of Science and Institute for Advanced Study, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR,
China
- These authors contributed equally to this work
| | - Cong Ye
- Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Kowloon, Hong Kong,
China
- These authors contributed equally to this work
| | - Qiqi Sun
- Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong,
China
- Center of Systems Biology and Human Health, School of Science and Institute for Advanced Study, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR,
China
| | - Christopher K.S. Leung
- Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Kowloon, Hong Kong,
China
| | - Jianan Y. Qu
- Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong,
China
- Center of Systems Biology and Human Health, School of Science and Institute for Advanced Study, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR,
China
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Rath D, Panda S. Contribution of rotational diffusivity towards the transport of antigens in heterogeneous immunosensors. Analyst 2015; 140:6579-87. [DOI: 10.1039/c5an00803d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Quantification of rotational diffusivities of biomarkers and their contribution to the overall transport using time resolved fluorescence anisotropy method would enable higher capture efficiency in heterogeneous immunosensors.
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Affiliation(s)
- Dharitri Rath
- Department of Chemical Engineering
- Indian Institute of Technology Kanpur
- Kanpur – 208 016
- India
- Centre for Environmental Sciences and Engineering
| | - Siddhartha Panda
- Department of Chemical Engineering
- Indian Institute of Technology Kanpur
- Kanpur – 208 016
- India
- Centre for Environmental Sciences and Engineering
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Blacker TS, Mann ZF, Gale JE, Ziegler M, Bain AJ, Szabadkai G, Duchen MR. Separating NADH and NADPH fluorescence in live cells and tissues using FLIM. Nat Commun 2014; 5:3936. [PMID: 24874098 PMCID: PMC4046109 DOI: 10.1038/ncomms4936] [Citation(s) in RCA: 342] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 04/23/2014] [Indexed: 02/07/2023] Open
Abstract
NAD is a key determinant of cellular energy metabolism. In contrast, its phosphorylated form, NADP, plays a central role in biosynthetic pathways and antioxidant defence. The reduced forms of both pyridine nucleotides are fluorescent in living cells but they cannot be distinguished, as they are spectrally identical. Here, using genetic and pharmacological approaches to perturb NAD(P)H metabolism, we find that fluorescence lifetime imaging (FLIM) differentiates quantitatively between the two cofactors. Systematic manipulations to change the balance between oxidative and glycolytic metabolism suggest that these states do not directly impact NAD(P)H fluorescence decay rates. The lifetime changes observed in cancers thus likely reflect shifts in the NADPH/NADH balance. Using a mathematical model, we use these experimental data to quantify the relative levels of NADH and NADPH in different cell types of a complex tissue, the mammalian cochlea. This reveals NADPH-enriched populations of cells, raising questions about their distinct metabolic roles. NAD and NADP play fundamentally different roles in cellular metabolism, and yet these pyridine nucleotides cannot be distinguished spectroscopically in living cells. Blacker et al. demonstrate that fluorescence lifetime imaging can be used to quantify NADPH/NADH balance in cultured cells and in the mammalian cochlea.
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Affiliation(s)
- Thomas S Blacker
- 1] Centre for Mathematics and Physics in the Life Sciences and Experimental Biology, University College London, London WC1E 6BT, UK [2] Research Department of Cell & Developmental Biology, University College London, London WC1E 6BT, UK [3] Department of Physics and Astronomy, University College London, London WC1E 6BT, UK
| | - Zoe F Mann
- 1] Research Department of Cell & Developmental Biology, University College London, London WC1E 6BT, UK [2] UCL Ear Institute, University College London, London WC1X 8EE, UK
| | - Jonathan E Gale
- 1] Research Department of Cell & Developmental Biology, University College London, London WC1E 6BT, UK [2] UCL Ear Institute, University College London, London WC1X 8EE, UK
| | - Mathias Ziegler
- Department of Molecular Biology, University of Bergen, N-5008 Bergen, Norway
| | - Angus J Bain
- Department of Physics and Astronomy, University College London, London WC1E 6BT, UK
| | - Gyorgy Szabadkai
- 1] Research Department of Cell & Developmental Biology, University College London, London WC1E 6BT, UK [2] Department of Biomedical Sciences, University of Padua and CNR Neuroscience Institute, Padua 35121, Italy [3]
| | - Michael R Duchen
- 1] Research Department of Cell & Developmental Biology, University College London, London WC1E 6BT, UK [2]
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Warren SC, Margineanu A, Alibhai D, Kelly DJ, Talbot C, Alexandrov Y, Munro I, Katan M, Dunsby C, French PMW. Rapid global fitting of large fluorescence lifetime imaging microscopy datasets. PLoS One 2013; 8:e70687. [PMID: 23940626 PMCID: PMC3734241 DOI: 10.1371/journal.pone.0070687] [Citation(s) in RCA: 145] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Accepted: 06/20/2013] [Indexed: 12/18/2022] Open
Abstract
Fluorescence lifetime imaging (FLIM) is widely applied to obtain quantitative information from fluorescence signals, particularly using Förster Resonant Energy Transfer (FRET) measurements to map, for example, protein-protein interactions. Extracting FRET efficiencies or population fractions typically entails fitting data to complex fluorescence decay models but such experiments are frequently photon constrained, particularly for live cell or in vivo imaging, and this leads to unacceptable errors when analysing data on a pixel-wise basis. Lifetimes and population fractions may, however, be more robustly extracted using global analysis to simultaneously fit the fluorescence decay data of all pixels in an image or dataset to a multi-exponential model under the assumption that the lifetime components are invariant across the image (dataset). This approach is often considered to be prohibitively slow and/or computationally expensive but we present here a computationally efficient global analysis algorithm for the analysis of time-correlated single photon counting (TCSPC) or time-gated FLIM data based on variable projection. It makes efficient use of both computer processor and memory resources, requiring less than a minute to analyse time series and multiwell plate datasets with hundreds of FLIM images on standard personal computers. This lifetime analysis takes account of repetitive excitation, including fluorescence photons excited by earlier pulses contributing to the fit, and is able to accommodate time-varying backgrounds and instrument response functions. We demonstrate that this global approach allows us to readily fit time-resolved fluorescence data to complex models including a four-exponential model of a FRET system, for which the FRET efficiencies of the two species of a bi-exponential donor are linked, and polarisation-resolved lifetime data, where a fluorescence intensity and bi-exponential anisotropy decay model is applied to the analysis of live cell homo-FRET data. A software package implementing this algorithm, FLIMfit, is available under an open source licence through the Open Microscopy Environment.
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Affiliation(s)
- Sean C Warren
- Department of Chemistry, Institute for Chemical Biology, Imperial College London, London, United Kingdom.
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