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Dmitriev RI, Intes X, Barroso MM. Luminescence lifetime imaging of three-dimensional biological objects. J Cell Sci 2021; 134:1-17. [PMID: 33961054 PMCID: PMC8126452 DOI: 10.1242/jcs.254763] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
A major focus of current biological studies is to fill the knowledge gaps between cell, tissue and organism scales. To this end, a wide array of contemporary optical analytical tools enable multiparameter quantitative imaging of live and fixed cells, three-dimensional (3D) systems, tissues, organs and organisms in the context of their complex spatiotemporal biological and molecular features. In particular, the modalities of luminescence lifetime imaging, comprising fluorescence lifetime imaging (FLI) and phosphorescence lifetime imaging microscopy (PLIM), in synergy with Förster resonance energy transfer (FRET) assays, provide a wealth of information. On the application side, the luminescence lifetime of endogenous molecules inside cells and tissues, overexpressed fluorescent protein fusion biosensor constructs or probes delivered externally provide molecular insights at multiple scales into protein-protein interaction networks, cellular metabolism, dynamics of molecular oxygen and hypoxia, physiologically important ions, and other physical and physiological parameters. Luminescence lifetime imaging offers a unique window into the physiological and structural environment of cells and tissues, enabling a new level of functional and molecular analysis in addition to providing 3D spatially resolved and longitudinal measurements that can range from microscopic to macroscopic scale. We provide an overview of luminescence lifetime imaging and summarize key biological applications from cells and tissues to organisms.
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Affiliation(s)
- Ruslan I. Dmitriev
- Tissue Engineering and Biomaterials Group, Department of
Human Structure and Repair, Faculty of Medicine and Health Sciences,
Ghent University, Ghent 9000,
Belgium
| | - Xavier Intes
- Department of Biomedical Engineering, Center for
Modeling, Simulation and Imaging for Medicine (CeMSIM),
Rensselaer Polytechnic Institute, Troy, NY
12180-3590, USA
| | - Margarida M. Barroso
- Department of Molecular and Cellular
Physiology, Albany Medical College,
Albany, NY 12208, USA
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2
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Ranawat H, Pal S, Mazumder N. Recent trends in two-photon auto-fluorescence lifetime imaging (2P-FLIM) and its biomedical applications. Biomed Eng Lett 2019; 9:293-310. [PMID: 31456890 PMCID: PMC6694381 DOI: 10.1007/s13534-019-00119-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 05/30/2019] [Accepted: 06/27/2019] [Indexed: 02/07/2023] Open
Abstract
Two photon fluorescence microscopy and the numerous technical advances to it have served as valuable tools in biomedical research. The fluorophores (exogenous or endogenous) absorb light and emit lower energy photons than the absorption energy and the emission (fluorescence) signal is measured using a fluorescence decay graph. Additionally, high spatial resolution images can be acquired in two photon fluorescence lifetime imaging (2P-FLIM) with improved penetration depth which helps in detection of fluorescence signal in vivo. 2P-FLIM is a non-invasive imaging technique in order to visualize cellular metabolic, by tracking intrinsic fluorophores present in it, such as nicotinamide adenine dinucleotide, flavin adenine dinucleotide and tryptophan etc. 2P-FLIM of these molecules enable the visualization of metabolic alterations, non-invasively. This comprehensive review discusses the numerous applications of 2P-FLIM towards cancer, neuro-degenerative, infectious diseases, and wound healing.
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Affiliation(s)
- Harsh Ranawat
- Department of Biophysics, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka 576104 India
| | - Sagnik Pal
- Department of Biophysics, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka 576104 India
| | - Nirmal Mazumder
- Department of Biophysics, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka 576104 India
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3
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Witte R, Andriasyan V, Georgi F, Yakimovich A, Greber UF. Concepts in Light Microscopy of Viruses. Viruses 2018; 10:E202. [PMID: 29670029 PMCID: PMC5923496 DOI: 10.3390/v10040202] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 04/12/2018] [Accepted: 04/16/2018] [Indexed: 12/11/2022] Open
Abstract
Viruses threaten humans, livestock, and plants, and are difficult to combat. Imaging of viruses by light microscopy is key to uncover the nature of known and emerging viruses in the quest for finding new ways to treat viral disease and deepening the understanding of virus–host interactions. Here, we provide an overview of recent technology for imaging cells and viruses by light microscopy, in particular fluorescence microscopy in static and live-cell modes. The review lays out guidelines for how novel fluorescent chemical probes and proteins can be used in light microscopy to illuminate cells, and how they can be used to study virus infections. We discuss advantages and opportunities of confocal and multi-photon microscopy, selective plane illumination microscopy, and super-resolution microscopy. We emphasize the prevalent concepts in image processing and data analyses, and provide an outlook into label-free digital holographic microscopy for virus research.
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Affiliation(s)
- Robert Witte
- Department of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
| | - Vardan Andriasyan
- Department of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
| | - Fanny Georgi
- Department of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
| | - Artur Yakimovich
- MRC Laboratory for Molecular Cell Biology, University College London, Gower St., London WC1E 6BT, UK.
| | - Urs F Greber
- Department of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
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4
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Becker W. Fluorescence lifetime imaging by multi-dimensional time correlated single photon counting. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.medpho.2015.02.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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5
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Wang SF, Chou YC, Mazumder N, Kao FJ, Nagy LD, Guengerich FP, Huang C, Lee HC, Lai PS, Ueng YF. 7-Ketocholesterol induces P-glycoprotein through PI3K/mTOR signaling in hepatoma cells. Biochem Pharmacol 2013; 86:548-60. [PMID: 23792120 PMCID: PMC4164904 DOI: 10.1016/j.bcp.2013.06.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 06/10/2013] [Accepted: 06/10/2013] [Indexed: 12/30/2022]
Abstract
7-Ketocholesterol (7-KC) is found at an elevated level in patients with cancer and chronic liver disease. The up-regulation of an efflux pump, P-glycoprotein (P-gp) leads to drug resistance. To elucidate the effect of 7-KC on P-gp, P-gp function and expression were investigated in hepatoma cell lines Huh-7 and HepG2 and in primary hepatocyte-derived HuS-E/2 cells. At a subtoxic concentration, 48-h exposure to 7-KC reduced the intracellular accumulation and cytotoxicity of P-gp substrate doxorubicin in hepatoma cells, but not in HuS-E/2 cells. In Huh-7 cells, 7-KC elevated efflux function through the activation of phosphatidylinositol 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) pathway. 7-KC activated the downstream protein synthesis initiation factor 4E-BP1 and induced P-gp expression post-transcriptionally. The stimulation of efflux was reversible and could not be prevented by N-acetyl cysteine. Total cellular ATP content remained the same, whereas the lactate production was increased and fluorescence lifetime of protein-bound NADH was shortened. These changes suggested a metabolic shift to glycolysis, but glycolytic inhibitors did not eliminate 7-KC-mediated P-gp induction. These results demonstrate that 7-KC induces P-gp through PI3K/mTOR signaling and decreased the cell-killing efficacy of doxorubicin in hepatoma cells.
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Affiliation(s)
- Sheng-Fan Wang
- National Research Institute of Chinese Medicine, No. 155-1, Li-Nong Street, Sec. 2, Taipei 112, Taiwan, ROC
- Department and Institute of Pharmacology, School of Medicine, National Yang-Ming University, No. 155, Li-Nong Street, Sec. 2,Taipei 112, Taiwan, ROC
- Department of Pharmacy, Taipei Veterans General Hospital, No. 201, Sec. 2, Shih-Pai Road, Taipei 112, Taiwan, ROC
| | - Yueh-Ching Chou
- Department and Institute of Pharmacology, School of Medicine, National Yang-Ming University, No. 155, Li-Nong Street, Sec. 2,Taipei 112, Taiwan, ROC
- Department of Pharmacy, Taipei Veterans General Hospital, No. 201, Sec. 2, Shih-Pai Road, Taipei 112, Taiwan, ROC
- Department of Pharmacy, Taipei Medical University, No. 250, Wuxing Street, Taipei 110, Taiwan, ROC
| | - Nirmal Mazumder
- Institute of Biophotonics, School of Biomedical Science and Engineering, National Yang-Ming University, No. 155, Li-Nong Street, Sec. 2, Taipei 112, Taiwan, ROC
| | - Fu-Jen Kao
- Institute of Biophotonics, School of Biomedical Science and Engineering, National Yang-Ming University, No. 155, Li-Nong Street, Sec. 2, Taipei 112, Taiwan, ROC
| | - Leslie D. Nagy
- Department of Biochemistry and Center in Molecular Toxicology, Vanderbilt University, School of Medicine, Nashville, TN 37232-0146, USA
| | - F. Peter Guengerich
- Department of Biochemistry and Center in Molecular Toxicology, Vanderbilt University, School of Medicine, Nashville, TN 37232-0146, USA
| | - Cheng Huang
- National Research Institute of Chinese Medicine, No. 155-1, Li-Nong Street, Sec. 2, Taipei 112, Taiwan, ROC
| | - Hsin-Chen Lee
- Department and Institute of Pharmacology, School of Medicine, National Yang-Ming University, No. 155, Li-Nong Street, Sec. 2,Taipei 112, Taiwan, ROC
| | - Ping-Shan Lai
- Department of Chemistry, College of Science, National Chung Hsin University, 250 Kuo Kuang Rd., Taichung 402, Taiwan, ROC
| | - Yune-Fang Ueng
- National Research Institute of Chinese Medicine, No. 155-1, Li-Nong Street, Sec. 2, Taipei 112, Taiwan, ROC
- Department and Institute of Pharmacology, School of Medicine, National Yang-Ming University, No. 155, Li-Nong Street, Sec. 2,Taipei 112, Taiwan, ROC
- Institute of Medical Sciences, Taipei Medical University, No. 250, Wuxing Street, Taipei 110, Taiwan, ROC
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Bek EJ, McMinn PC. The Pathogenesis and Prevention of Encephalitis due to Human Enterovirus 71. Curr Infect Dis Rep 2012; 14:397-407. [PMID: 22639066 DOI: 10.1007/s11908-012-0267-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Human enterovirus 71 (HEV71) has emerged as a major cause of viral encephalitis in Southeast Asia, with increased epidemic activity observed since 1997. This is reflected in a large increase in scientific publications relating directly to HEV71. New research is elucidating details of the viral life cycle, confirming similarities between HEV71 and other enteroviruses. Scavenger receptor B2 (SCARB2) is a receptor for HEV71, although other receptors are likely to be identified. Currently, the only strategies to prevent HEV71-associated disease are early diagnosis and aggressive supportive management of identified cases. As more information emerges regarding the molecular processes of HEV71 infection, further advances may lead to the development of effective antiviral treatments and ultimately a vaccine-protection strategy. The protective efficacies of several inactivated HEV71 vaccines have been confirmed in animal models, suggesting that an effective vaccine may become available in the next decade.
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Affiliation(s)
- Emily Jane Bek
- Infectious Diseases and Immunology, Sydney Medical School, The University of Sydney, Blackburn Building D06, Sydney, NSW, 2006, Australia
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7
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Buryakina TY, Su PT, Syu W, Chang CA, Fan HF, Kao FJ. Metabolism of HeLa cells revealed through autofluorescence lifetime upon infection with enterohemorrhagic Escherichia coli. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:101503. [PMID: 23223979 DOI: 10.1117/1.jbo.17.10.101503] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Fluorescence lifetime imaging microscopy (FLIM) is a sensitive technique in monitoring functional and conformational states of nicotinamide adenine dinucleotide reduced (NADH) and flavin adenine dinucleotide (FAD),main compounds participating in oxidative phosphorylation in cells. In this study, we have applied FLIM to characterize the metabolic changes in HeLa cells upon bacterial infection and made comparison with the results from the cells treated with staurosporine (STS), a well-known apoptosis inducer. The evolving of NADH's average autofluorescence lifetime during the 3 h after infection with enterohemorragic Escherichia coli (EHEC) or STS treatment has been observed. The ratio of the short and the long lifetime components' relative contributions of NADH increases with time, a fact indicating cellular metabolic activity, such as a decrease of oxidative phosphorylation over the course of infection, while opposite dynamics is observed in FAD. Being associated with mitochondria, FAD lifetimes and redox ratio could indicate heterogeneous mitochondrial function, microenvironment with bacterial infection, and further pathway to cell death. The redox ratios for both EHEC-infected and STS-treated HeLa cells have been observed and these observations also indicate possible apoptosis induced by bacterial infection.
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Affiliation(s)
- Tatyana Yu Buryakina
- Institute of Biophotonics, National Yang-Ming University, 155 Linong Street, Section 2, Taipei 11221, Taiwan
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8
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Adbul Rahim NA, Pelet S, Kamm RD, So PTC. Methodological considerations for global analysis of cellular FLIM/FRET measurements. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:026013. [PMID: 22463045 PMCID: PMC3382354 DOI: 10.1117/1.jbo.17.2.026013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Revised: 12/18/2011] [Accepted: 12/27/2011] [Indexed: 05/29/2023]
Abstract
Global algorithms can improve the analysis of fluorescence energy transfer (FRET) measurement based on fluorescence lifetime microscopy. However, global analysis of FRET data is also susceptible to experimental artifacts. This work examines several common artifacts and suggests remedial experimental protocols. Specifically, we examined the accuracy of different methods for instrument response extraction and propose an adaptive method based on the mean lifetime of fluorescent proteins. We further examined the effects of image segmentation and a priori constraints on the accuracy of lifetime extraction. Methods to test the applicability of global analysis on cellular data are proposed and demonstrated. The accuracy of global fitting degrades with lower photon count. By systematically tracking the effect of the minimum photon count on lifetime and FRET prefactors when carrying out global analysis, we demonstrate a correction procedure to recover the correct FRET parameters, allowing us to obtain protein interaction information even in dim cellular regions with photon counts as low as 100 per decay curve.
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Affiliation(s)
- Nur Aida Adbul Rahim
- Massachusetts Institute of Technology, Department of Mechanical Engineering, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139
| | - Serge Pelet
- Massachusetts Institute of Technology, Department of Biological Engineering, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139
| | - Roger D. Kamm
- Massachusetts Institute of Technology, Department of Mechanical Engineering, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139
- Massachusetts Institute of Technology, Department of Biological Engineering, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139
| | - Peter T. C. So
- Massachusetts Institute of Technology, Department of Mechanical Engineering, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139
- Massachusetts Institute of Technology, Department of Biological Engineering, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139
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9
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Lin PY, Lyu HC, Hsu CYS, Chang CS, Kao FJ. Imaging carious dental tissues with multiphoton fluorescence lifetime imaging microscopy. BIOMEDICAL OPTICS EXPRESS 2010; 2:149-58. [PMID: 21326645 PMCID: PMC3028490 DOI: 10.1364/boe.2.000149] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Revised: 12/07/2010] [Accepted: 12/16/2010] [Indexed: 05/30/2023]
Abstract
In this study, multiphoton excitation was utilized to image normal and carious dental tissues noninvasively. Unique structures in dental tissues were identified using the available multimodality (second harmonic, autofluorescence, and fluorescence lifetime analysis) without labeling. The collagen in dentin exhibits a strong second harmonic response. Both dentin and enamel emit strong autofluorescence that reveals in detail morphological features (such as dentinal tubules and enamel rods) and, despite their very similar spectral profiles, can be differentiated by lifetime analysis. Specifically, the carious dental tissue exhibits a greatly reduced autofluorescence lifetime, which result is consistent with the degree of demineralization, determined by micro-computed tomography. Our findings suggest that two-photon excited fluorescence lifetime imaging may be a promising tool for diagnosing and monitoring dental caries.
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Affiliation(s)
- Po-Yen Lin
- Institute of Biophotonics, National Yang-Ming University, Taipei 11221, Taiwan
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Hong-Chou Lyu
- Institute of Biophotonics, National Yang-Ming University, Taipei 11221, Taiwan
| | - Chin-Ying Stephen Hsu
- Department of Preventive Dentistry, Faculty of Dentistry, National University Health System, National University of Singapore, Singapore 119074
| | | | - Fu-Jen Kao
- Institute of Biophotonics, National Yang-Ming University, Taipei 11221, Taiwan
- Department of Photonics, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
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10
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Peng T. Strategies for antiviral screening targeting early steps of virus infection. Virol Sin 2010; 25:281-93. [PMID: 20960301 PMCID: PMC8227918 DOI: 10.1007/s12250-010-3135-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2010] [Accepted: 05/06/2010] [Indexed: 12/31/2022] Open
Abstract
Viral infection begins with the entry of the virus into the host target cell and initiates replication. For this reason, the virus entry machinery is an excellent target for antiviral therapeutics. In general, a virus life cycle includes several major steps: cell-surface attachment, entry, replication, assembly, and egress, while some viruses involve another stage called latency. The early steps of the virus life cycle include virus attachment, receptor binding, and entry. These steps involve the initial interactions between a virus and the host cell and thus are major determinants of the tropism of the virus infection, the nature of the virus replication, and the diseases resulting from the infection. Owing to the pathological importance of these early steps in the progress of viral infectious diseases, the development of inhibitors against these steps has been the focus of the pharmaceutical industry. In this review, Herpes Simplex Virus (HSV), Hepatitis C Virus (HCV), and Human Enterovirus 71 (EV71) were used as representatives of enveloped DNA, enveloped RNA, and non-enveloped viruses, respectively. The current mechanistic understanding of their attachment and entry, and the strategies for antagonist screenings are summarized herein.
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Affiliation(s)
- Tao Peng
- State Key Laboratory of Respiratory Diseases, Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.
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11
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Abstract
Over the past decade, Human enterovirus (HEV)71 has emerged as a highly significant cause of viral encephalitis in the south-east Asian region. A pattern of increased epidemic activity has been observable since 1997, the cause of which is unclear. Ongoing investigations into the molecular basis of HEV71 infection and virulence, in particular viral translation and replication, have confirmed similarities between HEV71 and other enteroviruses, including the prototype species Poliovirus, but more work is required in this field. Although several putative receptors for HEV71 have been identified, it remains likely that other, as yet unidentified, receptors exist. Work in several established animal models for HEV71 infection has confirmed the protective efficacy of several inactivated vaccines. As more information emerges regarding the molecular processes involved in HEV71 infection, further advances may lead to the development of more effective antiviral treatments and, ultimately, a vaccine protection strategy.
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Affiliation(s)
- Emily J Bek
- Infectious Diseases & Immunology, Sydney Medical School, Blackburn Building D06, The University of Sydney, NSW 2006, Australia
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12
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Li X, Kao FJ, Chuang CC, He S. Enhancing fluorescence of quantum dots by silica-coated gold nanorods under one- and two-photon excitation. OPTICS EXPRESS 2010; 18:11335-46. [PMID: 20588995 DOI: 10.1364/oe.18.011335] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Nano-composites of quantum dots (QDs) and gold nanorods (GNRs) or silica-coated GNRs (GNRs_SiO2) were synthesized. The attached GNRs modify the excitation intensity and spontaneous emission of QDs through the surface plasmonic effects. The fluorescence from QDs is enhanced and can be optimized by modifying the thickness of silica coated on GNRs, under both one- and two-photon excitations. The measurements of fluorescence intensity and lifetime demonstrate that the enhancement may be attributed to the matching of the localized surface plasmon resonance of GNR to the excitation wavelength. In addition to enhancing QD-fluorescence in QD-GNR@SiO2, GNRs also present as an effective contrast agent for bio-imaging, through light scattering and or two-photon emission, as well as for photo-thermal therapy. The composite's multifunctional characteristics are highly valuable and to be exploited in bio-applications.
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Affiliation(s)
- Xin Li
- Centre for Optical and Electromagnetic Research, State Key Laboratory for Modern Optical Instrumentation, Zhejiang University, Hangzhou, PR China
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13
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Affiliation(s)
- Mikhail Y. Berezin
- Department of Radiology, Washington University School of Medicine, 4525 Scott Ave, St. Louis, USA, Tel. 314-747-0701, 314-362-8599, fax 314-747-5191
| | - Samuel Achilefu
- Department of Radiology, Washington University School of Medicine, 4525 Scott Ave, St. Louis, USA, Tel. 314-747-0701, 314-362-8599, fax 314-747-5191
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Ghukasyan V, Hsu CC, Liu CR, Kao FJ, Cheng TH. Fluorescence lifetime dynamics of enhanced green fluorescent protein in protein aggregates with expanded polyglutamine. JOURNAL OF BIOMEDICAL OPTICS 2010; 15:016008. [PMID: 20210454 DOI: 10.1117/1.3290821] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Protein aggregation is one of the characteristic steps in a number of neurodegenerative diseases eventually leading to neuronal death and thorough study of aggregation is required for the development of effective therapy. We apply fluorescence lifetime imaging for the characterization of the fluorescence dynamics of the enhanced green fluorescent protein (eGFP) in fusion with the polyQ-expanded polyglutamine stretch. At the expansion of polyQ above 39 residues, it has an inherent propensity to form amyloid-like fibrils and aggregates, and is responsible for Huntington's disease. The results of the experiments show that expression of the eGFP in fusion with the 97Q protein leads to the decrease of the eGFP fluorescence lifetime by approximately 300 ps. This phenomenon does not appear in Hsp104-deficient cells, where the aggregation in polyQ is prevented. We demonstrate that the lifetime decrease observed is related to the aggregation per se and discuss the possible role of refractive index and homo-FRET in these dynamics.
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Affiliation(s)
- Vladimir Ghukasyan
- National Yang-Ming University, Institute of Biophotonics, Taipei, Taiwan
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15
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Lin WJ, Yang CY, Lin YC, Tsai MC, Yang CW, Tung CY, Ho PY, Kao FJ, Lin CH. Phafin2 modulates the structure and function of endosomes by a Rab5-dependent mechanism. Biochem Biophys Res Commun 2009; 391:1043-8. [PMID: 19995552 DOI: 10.1016/j.bbrc.2009.12.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2009] [Accepted: 12/03/2009] [Indexed: 12/20/2022]
Abstract
By regulating the amount of protein receptors on the cell membrane and the metabolisms of receptor-bound ligands, endocytosis represents one of the fundamental biological activities that regulate how cells respond to the environment. We report here that a Fab1-YotB-Vac1p-EEA1 (FYVE) domain-containing lipid associated protein, called Phafin2, is preferentially expressed in the human hepatocellular carcinoma (HCC) and is involved in the biogenesis of endosomes. Over-expression of Phafin2 or its FYVE domain results in the formation of enlarged endosomes that are still functional for endocytosis; the biogenesis of such abnormal organelles is mediated by phosphoinositide 3-kinases (PI3K) and Rab5 signaling. Using fluorescence resonance energy transfer measured by fluorescence lifetime imaging microscopy (FLIM-FRET), we further demonstrate in live cells that Phafin2 can directly activate Rab5. By modulating the receptor internalization/recycling and Rab5 activation, Phafin2 affects the density of membranous insulin receptors, and regulates the transcriptional activity of AP-1 that is downstream of the insulin signaling pathway. These results provide a vivid example that an endosome modulator, such as Phafin2, may control the cells' responses to the extracellular cues.
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Affiliation(s)
- Wen-Jie Lin
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan
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16
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Wang HW, Gukassyan V, Chen CT, Wei YH, Guo HW, Yu JS, Kao FJ. Differentiation of apoptosis from necrosis by dynamic changes of reduced nicotinamide adenine dinucleotide fluorescence lifetime in live cells. JOURNAL OF BIOMEDICAL OPTICS 2008; 13:054011. [PMID: 19021391 DOI: 10.1117/1.2975831] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Direct monitoring of cell death (i.e., apoptosis and necrosis) during or shortly after treatment is desirable in all cancer therapies to determine the outcome. Further differentiation of apoptosis from necrosis is crucial to optimize apoptosis-favored treatment protocols. We investigated the potential modality of using tissue intrinsic fluorescence chromophore, reduced nicotinamide adenine dinucleotide (NADH), for cell death detection. We imaged the fluorescence lifetime changes of NADH before and after staurosporine (STS)-induced mitochondria-mediated apoptosis and hydrogen peroxide (H2O2)-induced necrosis, respectively, using two-photon fluorescence lifetime imaging in live HeLa cells and 143B osteosarcoma. Time-lapsed lifetime images were acquired at the same site of cells. In untreated cells, the average lifetime of NADH fluorescence was approximately 1.3 ns. The NADH average fluorescence lifetime increased to approximately 3.5 ns within 15 min after 1 microM STS treatment and gradually decreased thereafter. The NADH fluorescence intensity increased within 15 min. In contrast, no significant dynamic lifetime change was found in cells treated with 1 mM H2O2. Our findings suggest that monitoring the NADH fluorescence lifetime may be a valuable noninvasive tool to detect apoptosis and distinguish apoptosis from necrosis for the optimization of apoptosis-favored treatment protocols and other clinical applications.
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Affiliation(s)
- Hsing-Wen Wang
- National Yang-Ming University, Institute of Biophotonics, Taipei, Taiwan.
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