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Apoptosis Detection in Retinal Ganglion Cells Using Quantitative Changes in Multichannel Fluorescence Colocalization. BIOSENSORS 2022; 12:bios12090693. [PMID: 36140078 PMCID: PMC9496076 DOI: 10.3390/bios12090693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 08/05/2022] [Accepted: 08/18/2022] [Indexed: 11/17/2022]
Abstract
KcapTR488 is a dual-fluorophore peptide sensor for the real-time reporting of programmed cell death by fluorescence imaging. KcapTR488 contains a nuclear localization sequence (NLS) conjugated with Texas Red, a caspase-cleavable sequence (DEVD), and a C-terminus conjugated to Alexa Fluor 488 (AF488). The synthesis and preliminary evaluation in cellulo of KcapTR488 for monitoring cell death by fluorescence imaging has been previously reported, but its utility in vivo has yet to be tested or validated. Herein, in vitro solution experiments verified the intramolecular fluorescence resonance energy transfer (FRET) between the two fluorophores and enabled a quantitative analysis of enzyme rates and selectivity. The sensor delivery kinetics in live rat models were quantified by ex vivo fluorescence microscopy. Studies in healthy control retinas demonstrated that KcapTR488 concentrated in the nucleus of retinal ganglion cells (RGC), with a strong colocalization of red and green fluorescence signals producing robust FRET signals, indicating an intact reporter. By contrast, using an acute but mild NMDA-induced retinal injury model, dual-color confocal ex vivo microscopy of cleaved KcapTR488 identified sensor activation as early as 2 h after injection. Quantitative changes in fluorescence colocalization were superior to changes in FRET for monitoring injury progression. Longitudinal monitoring revealed that the NLS-Texas Red fragment of the cleaved sensor moved out of the cell body, down the axon, and exited the retina, consistent with anterograde axonal transport. Thus, KcapTR488 may be a powerful tool to study RGC death pathways in live preclinical models of glaucoma.
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2
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Tools and Biomarkers for the Study of Retinal Ganglion Cell Degeneration. Int J Mol Sci 2022; 23:ijms23084287. [PMID: 35457104 PMCID: PMC9025234 DOI: 10.3390/ijms23084287] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 04/03/2022] [Accepted: 04/08/2022] [Indexed: 11/17/2022] Open
Abstract
The retina is part of the central nervous system, its analysis may provide an idea of the health and functionality, not only of the retina, but also of the entire central nervous system, as has been shown in Alzheimer’s or Parkinson’s diseases. Within the retina, the ganglion cells (RGC) are the neurons in charge of processing and sending light information to higher brain centers. Diverse insults and pathological states cause degeneration of RGC, leading to irreversible blindness or impaired vision. RGCs are the measurable endpoints in current research into experimental therapies and diagnosis in multiple ocular pathologies, like glaucoma. RGC subtype classifications are based on morphological, functional, genetical, and immunohistochemical aspects. Although great efforts are being made, there is still no classification accepted by consensus. Moreover, it has been observed that each RGC subtype has a different susceptibility to injury. Characterizing these subtypes together with cell death pathway identification will help to understand the degenerative process in the different injury and pathological models, and therefore prevent it. Here we review the known RGC subtypes, as well as the diagnostic techniques, probes, and biomarkers for programmed and unprogrammed cell death in RGC.
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3
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Gammon ST, Engel BJ, Gores GJ, Cressman E, Piwnica-Worms D, Millward SW. Mistiming Death: Modeling the Time-Domain Variability of Tumor Apoptosis and Implications for Molecular Imaging of Cell Death. Mol Imaging Biol 2021; 22:1310-1323. [PMID: 32519246 DOI: 10.1007/s11307-020-01509-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
PURPOSE Apoptosis, in the context of cancer, is a form of programmed cell death induced by chemotherapy, radiotherapy, and immunotherapy. As this is a central pathway in treatment response, considerable effort has been expended on the development of molecular imaging agents to non-invasively measure tumor apoptosis prior to quantitative changes in tumor dimensions. Despite these efforts, clinical trials directed at imaging apoptosis by PET, SPECT, and MRI have failed to robustly predict response to treatment with high sensitivity and specificity. Although these shortcomings may be linked to probe design, we propose that the combination of variability in the timing of maximal in vivo tumor apoptosis and sub-optimal sampling times fundamentally limits the predictive power of PET/SPECT apoptosis imaging. PROCEDURES Herein, we surveyed the literature describing the time course of therapy-induced tumor apoptosis in vivo and used these data to construct a mathematical model describing the onset, duration, amplitude, and variability of the apoptotic response. Uncertainty in the underlying time of initiation of tumor apoptosis was simulated by Gaussian, uniform, and Landau distributions centered at the median time-to-maximum apoptotic rate derived from the literature. We then computationally sampled these models for various durations to simulate PET/SPECT imaging agents with variable effective half-lives. RESULTS Models with a narrow Gaussian distribution of initiation times for tumor apoptosis predicted high contrast ratios and strong predictive values for all effective tracer half-lives. However, when uncertainty in apoptosis initiation times were simulated with uniform and Landau distributions, high contrast ratios and predictive values were only obtained with extremely long imaging windows (days). The imaging contrast ratios predicted in these models were consistent with those seen in pre-clinical apoptosis PET/SPECT imaging studies and suggest that uncertainty in the timing of tumor cell death plays a significant role in the maximal contrast obtainable. Moreover, when uncertainty in both apoptosis initiation and imaging start times were simulated, the predicted contrast ratios were dramatically reduced for all tracer half-lives. CONCLUSIONS These studies illustrate the effect of uncertainty of apoptosis initiation on the predictive power of PET/SPECT apoptosis imaging agents and suggest that long integration times are required to surmount uncertainty in the time domain of this biological process.
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Affiliation(s)
- Seth T Gammon
- Department of Cancer Systems Imaging, UT MD Anderson Cancer Center, Houston, TX, USA
| | - Brian J Engel
- Department of Cancer Systems Imaging, UT MD Anderson Cancer Center, Houston, TX, USA
| | | | - Erik Cressman
- Department of Interventional Radiology, UT MD Anderson Cancer Center, Houston, TX, USA
| | - David Piwnica-Worms
- Department of Cancer Systems Imaging, UT MD Anderson Cancer Center, Houston, TX, USA
| | - Steven W Millward
- Department of Cancer Systems Imaging, UT MD Anderson Cancer Center, Houston, TX, USA.
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4
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Park SJ, Woon QTS, Er JC, Wong BH, Liu X, Kang NY, Barathi VA, Silver DL, Chang YT. Application of Neuron-Selective Fluorescent Probe, NeuA, To Identify Mouse Retinal Degeneration. Chembiochem 2021; 22:1915-1919. [PMID: 33617145 DOI: 10.1002/cbic.202100011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Revised: 02/20/2021] [Indexed: 11/09/2022]
Abstract
The retina is part of the central nerve system (CNS) and has various interneurons and sensory neurons such as photoreceptor cells. Retinitis pigmentosa (RP) is an inherited condition that is characterized by photoreceptor degeneration. Herein, we developed a fluorescent probe-NeuA-for detecting retinal neuronal cells and applied NeuA to discriminate between healthy and RP retinas. The staining pattern of NeuA in the retinas of healthy and RP mouse models was examined in vitro, ex vivo and in vivo using confocal microscopy, the fluorescent fundus microscopy and optical coherent tomography (OCT). NeuA strongly stained the outer segment layer of photoreceptor cells and some bipolar cells in the healthy retina, but there was only weak staining in the photoreceptor degenerated retinas. Therefore, NeuA probe can be used as the detecting RP tools in the preclinical conditions.
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Affiliation(s)
- Sung-Jin Park
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research, Singapore, 138667, Republic of Singapore
| | - Queenie Tan Shu Woon
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore, 169856, Republic of Singapore
| | - Jun Cheng Er
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research, Singapore, 138667, Republic of Singapore
| | - Bernice H Wong
- Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, 169857, Republic of Singapore
| | - Xiao Liu
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Nam-Young Kang
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research, Singapore, 138667, Republic of Singapore.,Department of Creative IT Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Veluchamy A Barathi
- Singapore Eye Research Institute, Singapore, 169856, Republic of Singapore.,Eye-ACP, Duke-NUS Graduate Medical School, Singapore, 169857, Republic of Singapore.,Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119228, Republic of Singapore
| | - David L Silver
- Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, 169857, Republic of Singapore
| | - Young-Tae Chang
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research, Singapore, 138667, Republic of Singapore.,Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea.,Center for Self-assembly and Complexity, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
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5
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Kelada M, Hill D, Yap TE, Manzar H, Cordeiro MF. Innovations and revolutions in reducing retinal ganglion cell loss in glaucoma. EXPERT REVIEW OF OPHTHALMOLOGY 2020. [DOI: 10.1080/17469899.2021.1835470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Mary Kelada
- The Imperial College Ophthalmic Research Group (ICORG), Imperial College London NW1 5QH, UK
| | - Daniel Hill
- Glaucoma and Retinal Neurodegeneration Group, UCL Institute of Ophthalmology, London, UK
| | - Timothy E. Yap
- The Imperial College Ophthalmic Research Group (ICORG), Imperial College London NW1 5QH, UK
- The Western Eye Hospital, Imperial College Healthcare NHS Trust (ICHNT), London, UK
| | - Haider Manzar
- The Imperial College Ophthalmic Research Group (ICORG), Imperial College London NW1 5QH, UK
| | - M. Francesca Cordeiro
- The Imperial College Ophthalmic Research Group (ICORG), Imperial College London NW1 5QH, UK
- Glaucoma and Retinal Neurodegeneration Group, UCL Institute of Ophthalmology, London, UK
- The Western Eye Hospital, Imperial College Healthcare NHS Trust (ICHNT), London, UK
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6
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Le Roux LG, Qiu X, Jacobsen MC, Pagel MD, Gammon ST, R. Piwnica-Worms D, Schellingerhout D. Axonal Transport as an In Vivo Biomarker for Retinal Neuropathy. Cells 2020; 9:cells9051298. [PMID: 32456061 PMCID: PMC7291064 DOI: 10.3390/cells9051298] [Citation(s) in RCA: 2] [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: 03/26/2020] [Revised: 05/17/2020] [Accepted: 05/18/2020] [Indexed: 02/03/2023] Open
Abstract
We illuminate a possible explanatory pathophysiologic mechanism for retinal cellular neuropathy by means of a novel diagnostic method using ophthalmoscopic imaging and a molecular imaging agent targeted to fast axonal transport. The retinal neuropathies are a group of diseases with damage to retinal neural elements. Retinopathies lead to blindness but are typically diagnosed late, when substantial neuronal loss and vision loss have already occurred. We devised a fluorescent imaging agent based on the non-toxic C fragment of tetanus toxin (TTc), which is taken up and transported in neurons using the highly conserved fast axonal transport mechanism. TTc serves as an imaging biomarker for normal axonal transport and demonstrates impairment of axonal transport early in the course of an N-methyl-D-aspartic acid (NMDA)-induced excitotoxic retinopathy model in rats. Transport-related imaging findings were dramatically different between normal and retinopathic eyes prior to presumed neuronal cell death. This proof-of-concept study provides justification for future clinical translation.
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Affiliation(s)
- Lucia G. Le Roux
- Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX 77054, USA; (X.Q.); (M.D.P.); (S.T.G.); (D.R.P.-W.)
- Correspondence: ; Tel.: +713-563-5338
| | - Xudong Qiu
- Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX 77054, USA; (X.Q.); (M.D.P.); (S.T.G.); (D.R.P.-W.)
| | - Megan C. Jacobsen
- Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA;
| | - Mark D. Pagel
- Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX 77054, USA; (X.Q.); (M.D.P.); (S.T.G.); (D.R.P.-W.)
| | - Seth T. Gammon
- Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX 77054, USA; (X.Q.); (M.D.P.); (S.T.G.); (D.R.P.-W.)
| | - David R. Piwnica-Worms
- Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX 77054, USA; (X.Q.); (M.D.P.); (S.T.G.); (D.R.P.-W.)
| | - Dawid Schellingerhout
- Department of Neuroradiology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA;
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7
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Shamsher E, Davis BM, Yap TE, Guo L, Cordeiro MF. Neuroprotection in glaucoma: old concepts, new ideas. EXPERT REVIEW OF OPHTHALMOLOGY 2019. [DOI: 10.1080/17469899.2019.1604222] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Ehtesham Shamsher
- Department of Visual Neuroscience, University College London Institute of Ophthalmology, London, UK
| | - Benjamin M. Davis
- Department of Visual Neuroscience, University College London Institute of Ophthalmology, London, UK
- The Imperial College Ophthalmic Research Group (ICORG), Imperial College London, London
| | - Timothy E. Yap
- The Imperial College Ophthalmic Research Group (ICORG), Imperial College London, London
- The Western Eye Hospital, Imperial College Healthcare NHS Trust, London, UK
| | - Li Guo
- Department of Visual Neuroscience, University College London Institute of Ophthalmology, London, UK
| | - Maria Francesca Cordeiro
- Department of Visual Neuroscience, University College London Institute of Ophthalmology, London, UK
- The Imperial College Ophthalmic Research Group (ICORG), Imperial College London, London
- The Western Eye Hospital, Imperial College Healthcare NHS Trust, London, UK
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8
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9
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Luo ZW, Wang HT, Wang N, Sheng WW, Jin M, Lu Y, Bai YJ, Zou SQ, Pang YL, Xu H, Zhang X. Establishment of an adult zebrafish model of retinal neurodegeneration induced by NMDA. Int J Ophthalmol 2019; 12:1250-1261. [PMID: 31456914 PMCID: PMC6694058 DOI: 10.18240/ijo.2019.08.04] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 05/31/2019] [Indexed: 02/07/2023] Open
Abstract
AIM To establish a model of retinal neurodegeneration induced by N-Methyl-D-aspartic acid (NMDA) in adult zebrafish. METHODS We compared the effects of three different NMDA delivery methods on retinal neurodegeneration in adult zebrafish: immersion (I.M.), intravitreal injection (I.V.), and intraperitoneal injection (I.P.), and examined retinal pathology and degeneration by hematoxylin and eosin and TUNEL staining in the treated zebrafish. Effects of the NMDA receptor antagonist MK-801 and the natural product resveratrol on NMDA-induced retinal neurodegeneration were also assessed. RESULTS The thickened inner retina was seen in histology with 100 µmol/L NMDA by I.M. administration. Significant apoptosis in the retinal ganglion cell layer and retinal thickness reduction occurred in 0.5 mol/L NMDA I.P. administration group.Seizure-like behavioral changes, but no retinal histological alteration occurred in 16 mg/kg NMDA I.P. administration group. Resveratrol and MK-801 prevented NMDA-induced retinal neurodegeneration in the zebrafish. CONCLUSION Among the three drug administration methods, I.V. injection of NMDA is the most suitable for establishment of an acute retinal damage model in zebrafish. I.M. with NMDA is likely the best for use as a chronic retinal damage model. I.P. treatment with NMDA causes brain damage. Resveratrol and MK801 may be a clinically valuable treatment for retinal neurodegeneration.
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Affiliation(s)
- Zhi-Wen Luo
- Affiliated Eye Hospital of Nanchang University; Jiangxi Research Institute of Ophthalmology & Visual Science, Nanchang 330006, Jiangxi Province, China
- Queen Mary School of Nanchang University, Nanchang 330031, Jiangxi Province, China
| | - Han-Tsing Wang
- Institute of Life Science, Nanchang University, Nanchang 330031, Jiangxi Province, China
- Jiangxi Provincial Collaborative Innovation Center for Cardiovascular, Digestive and Neuropsychiatric Diseases, Nanchang 330031, Jiangxi Province, China
| | - Ning Wang
- Affiliated Eye Hospital of Nanchang University; Jiangxi Research Institute of Ophthalmology & Visual Science, Nanchang 330006, Jiangxi Province, China
- Queen Mary School of Nanchang University, Nanchang 330031, Jiangxi Province, China
| | - Wei-Wei Sheng
- Affiliated Eye Hospital of Nanchang University; Jiangxi Research Institute of Ophthalmology & Visual Science, Nanchang 330006, Jiangxi Province, China
- Queen Mary School of Nanchang University, Nanchang 330031, Jiangxi Province, China
| | - Ming Jin
- Affiliated Eye Hospital of Nanchang University; Jiangxi Research Institute of Ophthalmology & Visual Science, Nanchang 330006, Jiangxi Province, China
| | - Ye Lu
- Affiliated Eye Hospital of Nanchang University; Jiangxi Research Institute of Ophthalmology & Visual Science, Nanchang 330006, Jiangxi Province, China
| | - Yi-Jiang Bai
- Affiliated Eye Hospital of Nanchang University; Jiangxi Research Institute of Ophthalmology & Visual Science, Nanchang 330006, Jiangxi Province, China
- Queen Mary School of Nanchang University, Nanchang 330031, Jiangxi Province, China
| | - Su-Qi Zou
- Institute of Life Science, Nanchang University, Nanchang 330031, Jiangxi Province, China
- Jiangxi Provincial Collaborative Innovation Center for Cardiovascular, Digestive and Neuropsychiatric Diseases, Nanchang 330031, Jiangxi Province, China
| | - Yu-Lian Pang
- Affiliated Eye Hospital of Nanchang University; Jiangxi Research Institute of Ophthalmology & Visual Science, Nanchang 330006, Jiangxi Province, China
| | - Hong Xu
- Institute of Life Science, Nanchang University, Nanchang 330031, Jiangxi Province, China
- Jiangxi Provincial Collaborative Innovation Center for Cardiovascular, Digestive and Neuropsychiatric Diseases, Nanchang 330031, Jiangxi Province, China
| | - Xu Zhang
- Affiliated Eye Hospital of Nanchang University; Jiangxi Research Institute of Ophthalmology & Visual Science, Nanchang 330006, Jiangxi Province, China
- Jiangxi Provincial Collaborative Innovation Center for Cardiovascular, Digestive and Neuropsychiatric Diseases, Nanchang 330031, Jiangxi Province, China
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10
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Yang E, Al-Mugheiry TS, Normando EM, Cordeiro MF. Real-Time Imaging of Retinal Cell Apoptosis by Confocal Scanning Laser Ophthalmoscopy and Its Role in Glaucoma. Front Neurol 2018; 9:338. [PMID: 29867744 PMCID: PMC5962659 DOI: 10.3389/fneur.2018.00338] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 04/27/2018] [Indexed: 12/31/2022] Open
Abstract
Glaucoma is one of the leading causes of irreversible blindness in the world. It is characterized by the progressive loss of retinal ganglion cells (RGCs), mainly through the process of apoptosis. Glaucoma patients often come to clinical attention when irreversible loss of visual function has been already established; therefore, early recognition of RGC apoptosis is inordinately important in disease prevention. The novel technology called Detection of Apoptosing Retinal Cells (DARC) allows real-time in vivo quantification of apoptosing cells through the use of a fluorescent biomarker and a confocal scanning ophthalmoscope. A recent Phase I clinical trial has evaluated the safety of DARC and its ability to detect retinal apoptosis in glaucoma patients and healthy volunteers. Results suggest that DARC may have potential in the early detection of glaucoma, which could help alleviate the medical, social, and economic burden associated with this blinding condition.
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Affiliation(s)
- Elizabeth Yang
- The Western Eye Hospital, Imperial College Healthcare NHS Trust, London, United Kingdom.,The Imperial College Ophthalmic Research Group (ICORG), Imperial College London, London, United Kingdom
| | - Toby S Al-Mugheiry
- Queen Elizabeth Hospital, King's Lynn NHS Foundation Trust, Norfolk, United Kingdom
| | - Eduardo M Normando
- The Western Eye Hospital, Imperial College Healthcare NHS Trust, London, United Kingdom.,The Imperial College Ophthalmic Research Group (ICORG), Imperial College London, London, United Kingdom.,Insitute of Ophthalmology, University College London, London, United Kingdom
| | - Maria F Cordeiro
- The Western Eye Hospital, Imperial College Healthcare NHS Trust, London, United Kingdom.,The Imperial College Ophthalmic Research Group (ICORG), Imperial College London, London, United Kingdom.,Insitute of Ophthalmology, University College London, London, United Kingdom
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11
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Smith CA, Chauhan BC. In vivo imaging of adeno-associated viral vector labelled retinal ganglion cells. Sci Rep 2018; 8:1490. [PMID: 29367685 PMCID: PMC5784170 DOI: 10.1038/s41598-018-19969-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 01/11/2018] [Indexed: 01/10/2023] Open
Abstract
A defining characteristic of optic neuropathies, such as glaucoma, is progressive loss of retinal ganglion cells (RGCs). Current clinical tests only provide weak surrogates of RGC loss, but the possibility of optically visualizing RGCs and quantifying their rate of loss could represent a radical advance in the management of optic neuropathies. In this study we injected two different adeno-associated viral (AAV) vector serotypes in the vitreous to enable green fluorescent protein (GFP) labelling of RGCs in wild-type mice for in vivo and non-invasive imaging. GFP-labelled cells were detected by confocal scanning laser ophthalmoscopy 1-week post-injection and plateaued in density at 4 weeks. Immunohistochemical analysis 5-weeks post-injection revealed labelling specificity to RGCs to be significantly higher with the AAV2-DCX-GFP vector compared to the AAV2-CAG-GFP vector. There were no adverse functional or structural effects of the labelling method as determined with electroretinography and optical coherence tomography, respectively. The RGC-specific positive and negative scotopic threshold responses had similar amplitudes between control and experimental eyes, while inner retinal thickness was also unchanged after injection. As a positive control experiment, optic nerve transection resulted in a progressive loss of labelled RGCs. AAV vectors provide strong and long-lasting GFP labelling of RGCs without detectable adverse effects.
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Affiliation(s)
- Corey A Smith
- Department of Physiology and Biophysics, Dalhousie University, 5850 College Street, PO Box 15000, Halifax, Nova Scotia, B3H 4R2, Canada.,Retina and Optic Nerve Research Laboratory, Dalhousie University, 5850 College Street, PO Box 15000, Halifax, Nova Scotia, B3H 4R2, Canada
| | - Balwantray C Chauhan
- Department of Physiology and Biophysics, Dalhousie University, 5850 College Street, PO Box 15000, Halifax, Nova Scotia, B3H 4R2, Canada. .,Retina and Optic Nerve Research Laboratory, Dalhousie University, 5850 College Street, PO Box 15000, Halifax, Nova Scotia, B3H 4R2, Canada. .,Department of Ophthalmology and Visual Sciences, Dalhousie University, 1276 South Park Street, 2W Victoria, Halifax, Nova Scotia, B3H 2Y9, Canada.
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12
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Wang R, Fang D. Detection of phosphatidylserine in the plasma membrane of single apoptotic cells using electrochemiluminescence. RSC Adv 2017. [DOI: 10.1039/c6ra28031e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Phosphatidylserine in the plasma membrane of single apoptotic cells was detected using luminol electrochemiluminescence.
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Affiliation(s)
- Rui Wang
- School of Pharmacy
- Nanjing Medical University
- China
| | - Danjun Fang
- School of Pharmacy
- Nanjing Medical University
- China
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13
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Davis BM, Crawley L, Pahlitzsch M, Javaid F, Cordeiro MF. Glaucoma: the retina and beyond. Acta Neuropathol 2016; 132:807-826. [PMID: 27544758 PMCID: PMC5106492 DOI: 10.1007/s00401-016-1609-2] [Citation(s) in RCA: 159] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 08/02/2016] [Accepted: 08/10/2016] [Indexed: 12/31/2022]
Abstract
Over 60 million people worldwide are diagnosed with glaucomatous optic neuropathy, which is estimated to be responsible for 8.4 million cases of irreversible blindness globally. Glaucoma is associated with characteristic damage to the optic nerve and patterns of visual field loss which principally involves the loss of retinal ganglion cells (RGCs). At present, intraocular pressure (IOP) presents the only modifiable risk factor for glaucoma, although RGC and vision loss can continue in patients despite well-controlled IOP. This, coupled with the present inability to diagnose glaucoma until relatively late in the disease process, has led to intense investigations towards the development of novel techniques for the early diagnosis of disease. This review outlines our current understanding of the potential mechanisms underlying RGC and axonal loss in glaucoma. Similarities between glaucoma and other neurodegenerative diseases of the central nervous system are drawn before an overview of recent developments in techniques for monitoring RGC health is provided, including recent progress towards the development of RGC specific contrast agents. The review concludes by discussing techniques to assess glaucomatous changes in the brain using MRI and the clinical relevance of glaucomatous-associated changes in the visual centres of the brain.
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Affiliation(s)
| | - Laura Crawley
- Western Eye Hospital, Imperial College Healthcare NHS Trust, 153-173 Marylebone Road, London, UK
| | | | - Fatimah Javaid
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, UK
| | - Maria Francesca Cordeiro
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, UK.
- Western Eye Hospital, Imperial College Healthcare NHS Trust, 153-173 Marylebone Road, London, UK.
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14
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Mead B, Tomarev S. Evaluating retinal ganglion cell loss and dysfunction. Exp Eye Res 2016; 151:96-106. [PMID: 27523467 DOI: 10.1016/j.exer.2016.08.006] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 08/09/2016] [Accepted: 08/10/2016] [Indexed: 12/16/2022]
Abstract
Retinal ganglion cells (RGC) bear the sole responsibility of propagating visual stimuli to the brain. Their axons, which make up the optic nerve, project from the retina to the brain through the lamina cribrosa and in rodents, decussate almost entirely at the optic chiasm before synapsing at the superior colliculus. For many traumatic and degenerative ocular conditions, the dysfunction and/or loss of RGC is the primary determinant of visual loss and are the measurable endpoints in current research into experimental therapies. To actually measure these endpoints in rodent models, techniques must ascertain both the quantity of surviving RGC and their functional capacity. Quantification techniques include phenotypic markers of RGC, retrogradely transported fluorophores and morphological measurements of retinal thickness whereas functional assessments include electroretinography (flash and pattern) and visual evoked potential. The importance of the accuracy and reliability of these techniques cannot be understated, nor can the relationship between RGC death and dysfunction. The existence of up to 30 types of RGC complicates the measuring process, particularly as these may respond differently to disease and treatment. Since the above techniques may selectively identify and ignore particular subpopulations, their appropriateness as measures of RGC survival and function may be further limited. This review discusses the above techniques in the context of their subtype specificity.
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Affiliation(s)
- Ben Mead
- Section of Retinal Ganglion Cell Biology, Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Stanislav Tomarev
- Section of Retinal Ganglion Cell Biology, Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA
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Tsuda S, Tanaka Y, Kunikata H, Yokoyama Y, Yasuda M, Ito A, Nakazawa T. Real-time imaging of RGC death with a cell-impermeable nucleic acid dyeing compound after optic nerve crush in a murine model. Exp Eye Res 2016; 146:179-188. [PMID: 27013099 DOI: 10.1016/j.exer.2016.03.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 12/16/2015] [Accepted: 03/17/2016] [Indexed: 11/16/2022]
Abstract
The retinal ganglion cells (RGCs) are the main source of therapeutic targets for neuroprotective glaucoma treatment, and evaluating RGCs is key for effective glaucoma care. Thus, we developed a minimally invasive, quick, real-time method to evaluate RGC death in mice. In this article we describe the details of our method, report new results obtained from C57BL/6J mice, and report that our method was usable in wild type (WT) and knockout (KO) mice lacking an RGC-death-suppressing gene. It used a non-invasive confocal scanning laser ophthalmoscope (cSLO) and a low molecular weight, photo-switching, cell-impermeant, fluorescent nucleic acid dyeing compound, SYTOX orange (SO). The RGCs were retrogradely labeled with Fluorogold (FG), the optic nerve was crushed (ONC), and SO was injected into the vitreous. After ten minutes, RGC death was visualized with cSLO in vivo. The retinas were then extracted and flat mounted for histological observation. SO-labeled RGCs were counted in vivo and FG-labeled RGCs were counted in retinal flat mounts. The time course of RGC death was examined in Calpastatin KO mice and wild type (WT) mice. Our in vivo imaging method revealed that SO-positive dead RGCs were mainly present from 4 to 6 days after ONC, and the peak of RGC death was after 5 days. Moreover, the number of SO-positive dead RGCs after 5 days differed significantly in the Calpastatin KO mice and the WT mice. Counting FG-labeled RGCs in isolated retinas confirmed these results. Thus, real-time imaging with SO was able to quickly quantify ONC-induced RGC death. This technique may aid research into RGC death and the development of new neuroprotective therapies for glaucoma.
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Affiliation(s)
- Satoru Tsuda
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Japan
| | - Yuji Tanaka
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Japan
| | - Hiroshi Kunikata
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Japan; Department of Retinal Disease Control, Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Yu Yokoyama
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Japan
| | - Masayuki Yasuda
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Japan
| | - Azusa Ito
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Japan
| | - Toru Nakazawa
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Japan; Department of Retinal Disease Control, Tohoku University Graduate School of Medicine, Miyagi, Japan; Department of Advanced Ophthalmic Medicine, Tohoku University Graduate School of Medicine, Miyagi, Japan.
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Zaro JL, Shen WC. Cationic and amphipathic cell-penetrating peptides (CPPs): Their structures and in vivo studies in drug delivery. Front Chem Sci Eng 2015. [DOI: 10.1007/s11705-015-1538-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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17
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Advances in retinal ganglion cell imaging. Eye (Lond) 2015; 29:1260-9. [PMID: 26293138 DOI: 10.1038/eye.2015.154] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 06/29/2015] [Indexed: 12/18/2022] Open
Abstract
Glaucoma is one of the leading causes of blindness worldwide and will affect 79.6 million people worldwide by 2020. It is caused by the progressive loss of retinal ganglion cells (RGCs), predominantly via apoptosis, within the retinal nerve fibre layer and the corresponding loss of axons of the optic nerve head. One of its most devastating features is its late diagnosis and the resulting irreversible visual loss that is often predictable. Current diagnostic tools require significant RGC or functional visual field loss before the threshold for detection of glaucoma may be reached. To propel the efficacy of therapeutics in glaucoma, an earlier diagnostic tool is required. Recent advances in retinal imaging, including optical coherence tomography, confocal scanning laser ophthalmoscopy, and adaptive optics, have propelled both glaucoma research and clinical diagnostics and therapeutics. However, an ideal imaging technique to diagnose and monitor glaucoma would image RGCs non-invasively with high specificity and sensitivity in vivo. It may confirm the presence of healthy RGCs, such as in transgenic models or retrograde labelling, or detect subtle changes in the number of unhealthy or apoptotic RGCs, such as detection of apoptosing retinal cells (DARC). Although many of these advances have not yet been introduced to the clinical arena, their successes in animal studies are enthralling. This review will illustrate the challenges of imaging RGCs, the main retinal imaging modalities, the in vivo techniques to augment these as specific RGC-imaging tools and their potential for translation to the glaucoma clinic.
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Rasmussen CA, Kaufman PL. Exciting directions in glaucoma. Can J Ophthalmol 2015; 49:534-43. [PMID: 25433744 DOI: 10.1016/j.jcjo.2014.08.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 08/13/2014] [Indexed: 01/15/2023]
Abstract
Glaucoma is a complex, life-long disease that requires an individualized, multifaceted approach to treatment. Most patients will be started on topical ocular hypotensive eyedrop therapy, and over time multiple classes of drugs will be needed to control their intraocular pressure. The search for drugs with novel mechanisms of action, to treat those who do not achieve adequate intraocular pressure control with, or become refractory to, current therapeutics, is ongoing, as is the search for more efficient, targeted drug delivery methods. Gene-transfer and stem-cell applications for glaucoma therapeutics are moving forward. Advances in imaging technologies improve our understanding of glaucoma pathophysiology and enable more refined patient evaluation and monitoring, improving patient outcomes.
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Affiliation(s)
- Carol A Rasmussen
- Department of Ophthalmology & Visual Sciences, School of Medicine & Public Health, University of Wisconsin-Madison, Madison, WI, USA..
| | - Paul L Kaufman
- Department of Ophthalmology & Visual Sciences, School of Medicine & Public Health, University of Wisconsin-Madison, Madison, WI, USA
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van Duijnhoven SMJ, Robillard MS, Langereis S, Grüll H. Bioresponsive probes for molecular imaging: concepts and in vivo applications. CONTRAST MEDIA & MOLECULAR IMAGING 2015; 10:282-308. [PMID: 25873263 DOI: 10.1002/cmmi.1636] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 01/24/2015] [Accepted: 02/03/2015] [Indexed: 12/30/2022]
Abstract
Molecular imaging is a powerful tool to visualize and characterize biological processes at the cellular and molecular level in vivo. In most molecular imaging approaches, probes are used to bind to disease-specific biomarkers highlighting disease target sites. In recent years, a new subset of molecular imaging probes, known as bioresponsive molecular probes, has been developed. These probes generally benefit from signal enhancement at the site of interaction with its target. There are mainly two classes of bioresponsive imaging probes. The first class consists of probes that show direct activation of the imaging label (from "off" to "on" state) and have been applied in optical imaging and magnetic resonance imaging (MRI). The other class consists of probes that show specific retention of the imaging label at the site of target interaction and these probes have found application in all different imaging modalities, including photoacoustic imaging and nuclear imaging. In this review, we present a comprehensive overview of bioresponsive imaging probes in order to discuss the various molecular imaging strategies. The focus of the present article is the rationale behind the design of bioresponsive molecular imaging probes and their potential in vivo application for the detection of endogenous molecular targets in pathologies such as cancer and cardiovascular disease.
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Affiliation(s)
- Sander M J van Duijnhoven
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.,Department of Minimally Invasive Healthcare, Philips Research, Eindhoven, The Netherlands
| | - Marc S Robillard
- Department of Minimally Invasive Healthcare, Philips Research, Eindhoven, The Netherlands
| | - Sander Langereis
- Department of Minimally Invasive Healthcare, Philips Research, Eindhoven, The Netherlands
| | - Holger Grüll
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.,Department of Minimally Invasive Healthcare, Philips Research, Eindhoven, The Netherlands
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Bizrah M, Dakin SC, Guo L, Rahman F, Parnell M, Normando E, Nizari S, Davis B, Younis A, Cordeiro MF. A semi-automated technique for labeling and counting of apoptosing retinal cells. BMC Bioinformatics 2014; 15:169. [PMID: 24902592 PMCID: PMC4063694 DOI: 10.1186/1471-2105-15-169] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 05/14/2014] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Retinal ganglion cell (RGC) loss is one of the earliest and most important cellular changes in glaucoma. The DARC (Detection of Apoptosing Retinal Cells) technology enables in vivo real-time non-invasive imaging of single apoptosing retinal cells in animal models of glaucoma and Alzheimer's disease. To date, apoptosing RGCs imaged using DARC have been counted manually. This is time-consuming, labour-intensive, vulnerable to bias, and has considerable inter- and intra-operator variability. RESULTS A semi-automated algorithm was developed which enabled automated identification of apoptosing RGCs labeled with fluorescent Annexin-5 on DARC images. Automated analysis included a pre-processing stage involving local-luminance and local-contrast "gain control", a "blob analysis" step to differentiate between cells, vessels and noise, and a method to exclude non-cell structures using specific combined 'size' and 'aspect' ratio criteria. Apoptosing retinal cells were counted by 3 masked operators, generating 'Gold-standard' mean manual cell counts, and were also counted using the newly developed automated algorithm. Comparison between automated cell counts and the mean manual cell counts on 66 DARC images showed significant correlation between the two methods (Pearson's correlation coefficient 0.978 (p < 0.001), R Squared = 0.956. The Intraclass correlation coefficient was 0.986 (95% CI 0.977-0.991, p < 0.001), and Cronbach's alpha measure of consistency = 0.986, confirming excellent correlation and consistency. No significant difference (p = 0.922, 95% CI: -5.53 to 6.10) was detected between the cell counts of the two methods. CONCLUSIONS The novel automated algorithm enabled accurate quantification of apoptosing RGCs that is highly comparable to manual counting, and appears to minimise operator-bias, whilst being both fast and reproducible. This may prove to be a valuable method of quantifying apoptosing retinal cells, with particular relevance to translation in the clinic, where a Phase I clinical trial of DARC in glaucoma patients is due to start shortly.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - M Francesca Cordeiro
- Glaucoma and Retinal Neurodegeneration Group, UCL Institute of Ophthalmology, London, UK.
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Chong RS, Martin KR. Retinal ganglion cell dendrites and glaucoma: a case of missing the wood for the trees? EXPERT REVIEW OF OPHTHALMOLOGY 2014. [DOI: 10.1586/17469899.2014.917048] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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