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Yang F, Almasieh M, Levin LA. In Vivo Imaging of Secondary Neurodegeneration Associated With Phosphatidylserine Externalization Along Axotomized Axons. Invest Ophthalmol Vis Sci 2024; 65:24. [PMID: 38345553 PMCID: PMC10866172 DOI: 10.1167/iovs.65.2.24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 12/11/2023] [Indexed: 02/15/2024] Open
Abstract
Purpose Axonal degeneration in acute and chronic disorders is well-characterized, comprising retrograde (proximal) and Wallerian (distal) degeneration, but the mechanism of propagation remains less understood. Methods Laser injury with a diode-pumped solid-state 532 nm laser was used to axotomize retinal ganglion cell axons. We used confocal in vivo imaging to demonstrate that phosphatidylserine externalization is a biomarker of early axonal degeneration after selective intraretinal axotomy. Results Quantitative dynamic analysis revealed that the rate of axonal degeneration was fastest within 40 minutes, then decreased exponentially afterwards. Axonal degeneration was constrained within the same axotomized axonal bundles. Remarkably, axon degeneration arising from the site of injury induced a secondary degeneration of distal normal axons. Conclusions Axonal degeneration in vivo is a progressive process associated with phosphatidylserine externalization, which can propagate not only along the axon but to adjacent uninjured axons. This finding has implications for acute and chronic neurodegenerative disorders associated with axonal injury.
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Affiliation(s)
- Fan Yang
- Department of Ophthalmology and Visual Sciences, McGill University, Montreal, Canada
| | - Mohammadali Almasieh
- Department of Ophthalmology and Visual Sciences, McGill University, Montreal, Canada
| | - Leonard A. Levin
- Department of Ophthalmology and Visual Sciences, McGill University, Montreal, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, Canada
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2
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You W, Knoops K, Boesten I, Berendschot TTJM, van Zandvoort MAMJ, Benedikter BJ, Webers CAB, Reutelingsperger CPM, Gorgels TGMF. A time window for rescuing dying retinal ganglion cells. Cell Commun Signal 2024; 22:88. [PMID: 38297331 PMCID: PMC10832163 DOI: 10.1186/s12964-023-01427-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 12/08/2023] [Indexed: 02/02/2024] Open
Abstract
BACKGROUND Retinal ganglion cell (RGC) degeneration and death cause vision loss in patients with glaucoma. Regulated cell death, once initiated, is generally considered to be an irreversible process. Recently, we showed that, by timely removing the cell death stimulus, stressed neuronal PC12 cells can recover from phosphatidylserine (PS) exposure, nuclear shrinkage, DNA damage, mitochondrial fragmentation, mitochondrial membrane potential loss, and retraction of neurites, all hallmarks of an activated cell death program. Whether the cell death process can be reversed in neurons of the central nervous system, like RGCs, is still unknown. Here, we studied reversibility of the activated cell death program in primary rat RGCs (prRGCs). METHODS prRGCs were exposed to ethanol (5%, vol/vol) to induce cell death. At different stages of the cell death process, ethanol was removed by washing and injured prRGCs were further cultured in fresh medium to see whether they recovered. The dynamics of single cells were monitored by high-resolution live-cell spinning disk microscopy. PS exposure, mitochondrial structure, membrane potential, and intracellular Ca2+ were revealed by annexin A5-FITC, Mito-tracker, TMRM, and Fluo 8-AM staining, respectively. The distribution of cytochrome c was investigated by immunofluorescence. The ultrastructure of mitochondria was studied by electron microscopy. RESULTS Analysis of temporal relationships between mitochondrial changes and PS exposure showed that fragmentation of the mitochondrial network and loss of mitochondrial membrane potential occurred before PS exposure. Mitochondrial changes proceeded caspase-independently, while PS exposure was caspase dependent. Interestingly, prRGCs recovered quickly from these mitochondrial changes but not from PS exposure at the plasma membrane. Correlative light and electron microscopy showed that stress-induced decrease in mitochondrial area, length and cristae number was reversible. Intracellular Ca2+ was elevated during this stage of reversible mitochondrial injury, but there was no sign of mitochondrial cytochrome c release. CONCLUSIONS Our study demonstrates that RGCs with impaired mitochondrial structure and function can fully recover if there is no mitochondrial cytochrome c release yet, and no PS is exposed at the plasma membrane. This finding indicates that there is a time window for rescuing dying or injured RGCs, by simply removing the cell death stimulus. Video Abstract.
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Affiliation(s)
- Wenting You
- University Eye Clinic Maastricht UMC+, Maastricht University Medical Center+, Maastricht, 6229 HX, The Netherlands
- Department of Biochemistry, CARIM School for Cardiovascular Disease, Maastricht University, Maastricht, 6229 ER, The Netherlands
- Department of Mental Health and Neuroscience, Maastricht University, Maastricht, 6229 ER, The Netherlands
| | - Kèvin Knoops
- The Microscopy CORE lab, Maastricht Multimodal Molecular Imaging Institute, Maastricht University, Maastricht, 6229 ER, The Netherlands
| | - Iris Boesten
- University Eye Clinic Maastricht UMC+, Maastricht University Medical Center+, Maastricht, 6229 HX, The Netherlands
| | - Tos T J M Berendschot
- University Eye Clinic Maastricht UMC+, Maastricht University Medical Center+, Maastricht, 6229 HX, The Netherlands
| | - Marc A M J van Zandvoort
- Department of Molecular Cell Biology, CARIM School for Cardiovascular Disease, Maastricht University, Maastricht, 6229 ER, The Netherlands
- Institute of Molecular Cardiovascular Research (IMCAR), Universitätsklinikum Aachen, 52074, Aachen, Germany
| | - Birke J Benedikter
- University Eye Clinic Maastricht UMC+, Maastricht University Medical Center+, Maastricht, 6229 HX, The Netherlands
| | - Carroll A B Webers
- University Eye Clinic Maastricht UMC+, Maastricht University Medical Center+, Maastricht, 6229 HX, The Netherlands
| | - Chris P M Reutelingsperger
- Department of Biochemistry, CARIM School for Cardiovascular Disease, Maastricht University, Maastricht, 6229 ER, The Netherlands.
| | - Theo G M F Gorgels
- University Eye Clinic Maastricht UMC+, Maastricht University Medical Center+, Maastricht, 6229 HX, The Netherlands.
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3
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Du Y, Cai M, Mu J, Li X, Song Y, Yuan X, Hua X, Guo S. Type I Collagen-Adhesive and ROS-Scavenging Nanoreactors Enhanced Retinal Ganglion Cell Survival in an Experimental Optic Nerve Crush Model. Macromol Rapid Commun 2023; 44:e2300389. [PMID: 37661804 DOI: 10.1002/marc.202300389] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 08/30/2023] [Indexed: 09/05/2023]
Abstract
Traumatic optic neuropathy (TON) is a severe condition characterized by retinal ganglion cell (RGC) death, often leading to irreversible vision loss, and the death of RGCs is closely associated with oxidative stress. Unfortunately, effective treatment options for TON are lacking. To address this, catalase (CAT) is encapsulated in a tannic acid (TA)/poly(ethylenimine)-crosslinked hollow nanoreactor (CAT@PTP), which exhibited enhanced anchoring in the retina due to TA-collagen adhesion. The antioxidative activity of both CAT and TA synergistically eliminated reactive oxygen species (ROS) to save RGCs in the retina, thereby treating TON. In vitro experiments demonstrated that the nanoreactors preserve the enzymatic activity of CAT and exhibit high adhesion to type I collagen. The combination of CAT and TA-based nanoreactors enhanced ROS elimination while maintaining high biocompatibility. In an optic nerve crush rat model, CAT@PTP is effectively anchored to the retina via TA-collagen adhesion after a single vitreous injection, and RGCs are significantly preserved without adverse events. CAT@PTP exhibited a protective effect on retinal function. Given the abundance of collagen that exists in ocular tissues, these findings may contribute to the further application of this multifunctional nanoreactor in ocular diseases to improve therapeutic efficacy and reduce adverse effects.
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Affiliation(s)
- Yuyuan Du
- Key Laboratory of Functional Polymer Materials of Ministry of Education, State Key Laboratory of Medicinal Chemical Biology, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Maoyu Cai
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, 300020, China
- Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Eye Institute, Tianjin Eye Hospital, Tianjin, 300020, China
| | - Jingqing Mu
- Aier Eye Institute, Changsha, 410015, China
- Tianjin Aier Eye Hospital, Tianjin, 300190, China
| | - Xingwei Li
- Key Laboratory of Functional Polymer Materials of Ministry of Education, State Key Laboratory of Medicinal Chemical Biology, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Yapeng Song
- Key Laboratory of Functional Polymer Materials of Ministry of Education, State Key Laboratory of Medicinal Chemical Biology, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Xiaoyong Yuan
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, 300020, China
- Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Eye Institute, Tianjin Eye Hospital, Tianjin, 300020, China
| | - Xia Hua
- Aier Eye Institute, Changsha, 410015, China
- Tianjin Aier Eye Hospital, Tianjin, 300190, China
| | - Shutao Guo
- Key Laboratory of Functional Polymer Materials of Ministry of Education, State Key Laboratory of Medicinal Chemical Biology, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin, 300071, China
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Maiese K. Cornerstone Cellular Pathways for Metabolic Disorders and Diabetes Mellitus: Non-Coding RNAs, Wnt Signaling, and AMPK. Cells 2023; 12:2595. [PMID: 37998330 PMCID: PMC10670256 DOI: 10.3390/cells12222595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 10/31/2023] [Accepted: 11/07/2023] [Indexed: 11/25/2023] Open
Abstract
Metabolic disorders and diabetes (DM) impact more than five hundred million individuals throughout the world and are insidious in onset, chronic in nature, and yield significant disability and death. Current therapies that address nutritional status, weight management, and pharmacological options may delay disability but cannot alter disease course or functional organ loss, such as dementia and degeneration of systemic bodily functions. Underlying these challenges are the onset of aging disorders associated with increased lifespan, telomere dysfunction, and oxidative stress generation that lead to multi-system dysfunction. These significant hurdles point to the urgent need to address underlying disease mechanisms with innovative applications. New treatment strategies involve non-coding RNA pathways with microRNAs (miRNAs) and circular ribonucleic acids (circRNAs), Wnt signaling, and Wnt1 inducible signaling pathway protein 1 (WISP1) that are dependent upon programmed cell death pathways, cellular metabolic pathways with AMP-activated protein kinase (AMPK) and nicotinamide, and growth factor applications. Non-coding RNAs, Wnt signaling, and AMPK are cornerstone mechanisms for overseeing complex metabolic pathways that offer innovative treatment avenues for metabolic disease and DM but will necessitate continued appreciation of the ability of each of these cellular mechanisms to independently and in unison influence clinical outcome.
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Affiliation(s)
- Kenneth Maiese
- Cellular and Molecular Signaling, New York, NY 10022, USA
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5
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Maiese K. The impact of aging and oxidative stress in metabolic and nervous system disorders: programmed cell death and molecular signal transduction crosstalk. Front Immunol 2023; 14:1273570. [PMID: 38022638 PMCID: PMC10663950 DOI: 10.3389/fimmu.2023.1273570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Accepted: 10/23/2023] [Indexed: 12/01/2023] Open
Abstract
Life expectancy is increasing throughout the world and coincides with a rise in non-communicable diseases (NCDs), especially for metabolic disease that includes diabetes mellitus (DM) and neurodegenerative disorders. The debilitating effects of metabolic disorders influence the entire body and significantly affect the nervous system impacting greater than one billion people with disability in the peripheral nervous system as well as with cognitive loss, now the seventh leading cause of death worldwide. Metabolic disorders, such as DM, and neurologic disease remain a significant challenge for the treatment and care of individuals since present therapies may limit symptoms but do not halt overall disease progression. These clinical challenges to address the interplay between metabolic and neurodegenerative disorders warrant innovative strategies that can focus upon the underlying mechanisms of aging-related disorders, oxidative stress, cell senescence, and cell death. Programmed cell death pathways that involve autophagy, apoptosis, ferroptosis, and pyroptosis can play a critical role in metabolic and neurodegenerative disorders and oversee processes that include insulin resistance, β-cell function, mitochondrial integrity, reactive oxygen species release, and inflammatory cell activation. The silent mating type information regulation 2 homolog 1 (Saccharomyces cerevisiae) (SIRT1), AMP activated protein kinase (AMPK), and Wnt1 inducible signaling pathway protein 1 (WISP1) are novel targets that can oversee programmed cell death pathways tied to β-nicotinamide adenine dinucleotide (NAD+), nicotinamide, apolipoprotein E (APOE), severe acute respiratory syndrome (SARS-CoV-2) exposure with coronavirus disease 2019 (COVID-19), and trophic factors, such as erythropoietin (EPO). The pathways of programmed cell death, SIRT1, AMPK, and WISP1 offer exciting prospects for maintaining metabolic homeostasis and nervous system function that can be compromised during aging-related disorders and lead to cognitive impairment, but these pathways have dual roles in determining the ultimate fate of cells and organ systems that warrant thoughtful insight into complex autofeedback mechanisms.
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Affiliation(s)
- Kenneth Maiese
- Innovation and Commercialization, National Institutes of Health, Bethesda, MD, United States
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Maiese K. Cognitive Impairment in Multiple Sclerosis. Bioengineering (Basel) 2023; 10:871. [PMID: 37508898 PMCID: PMC10376413 DOI: 10.3390/bioengineering10070871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 07/19/2023] [Accepted: 07/21/2023] [Indexed: 07/30/2023] Open
Abstract
Almost three million individuals suffer from multiple sclerosis (MS) throughout the world, a demyelinating disease in the nervous system with increased prevalence over the last five decades, and is now being recognized as one significant etiology of cognitive loss and dementia. Presently, disease modifying therapies can limit the rate of relapse and potentially reduce brain volume loss in patients with MS, but unfortunately cannot prevent disease progression or the onset of cognitive disability. Innovative strategies are therefore required to address areas of inflammation, immune cell activation, and cell survival that involve novel pathways of programmed cell death, mammalian forkhead transcription factors (FoxOs), the mechanistic target of rapamycin (mTOR), AMP activated protein kinase (AMPK), the silent mating type information regulation 2 homolog 1 (Saccharomyces cerevisiae) (SIRT1), and associated pathways with the apolipoprotein E (APOE-ε4) gene and severe acute respiratory syndrome coronavirus (SARS-CoV-2). These pathways are intertwined at multiple levels and can involve metabolic oversight with cellular metabolism dependent upon nicotinamide adenine dinucleotide (NAD+). Insight into the mechanisms of these pathways can provide new avenues of discovery for the therapeutic treatment of dementia and loss in cognition that occurs during MS.
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Affiliation(s)
- Kenneth Maiese
- Cellular and Molecular Signaling, New York, NY 10022, USA
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7
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Torrens JN, Hetzer SM, Evanson NK. Brief Oxygen Exposure after Traumatic Brain Injury Hastens Recovery and Promotes Adaptive Chronic Endoplasmic Reticulum Stress Responses. Int J Mol Sci 2023; 24:9831. [PMID: 37372978 DOI: 10.3390/ijms24129831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 06/02/2023] [Accepted: 06/05/2023] [Indexed: 06/29/2023] Open
Abstract
Traumatic brain injury (TBI) is a major public health concern, particularly in adolescents who have a higher mortality and incidence of visual pathway injury compared to adult patients. Likewise, we have found disparities between adult and adolescent TBI outcomes in rodents. Most interestingly, adolescents suffer a prolonged apneic period immediately post-injury, leading to higher mortality; therefore, we implemented a brief oxygen exposure paradigm to circumvent this increased mortality. Adolescent male mice experienced a closed-head weight-drop TBI and were then exposed to 100% O2 until normal breathing returned or recovered in room air. We followed mice for 7 and 30 days and assessed their optokinetic response; retinal ganglion cell loss; axonal degeneration; glial reactivity; and retinal ER stress protein levels. O2 reduced adolescent mortality by 40%, improved post-injury visual acuity, and reduced axonal degeneration and gliosis in optical projection regions. ER stress protein expression was altered in injured mice, and mice given O2 utilized different ER stress pathways in a time-dependent manner. Finally, O2 exposure may be mediating these ER stress responses through regulation of the redox-sensitive ER folding protein ERO1α, which has been linked to a reduction in the toxic effects of free radicals in other animal models of ER stress.
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Affiliation(s)
- Jordyn N Torrens
- Division of Pediatric Rehabilitation Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Shelby M Hetzer
- Neuroscience Graduate Program, University of Cincinnati, Cincinnati, OH 45267, USA
| | - Nathan K Evanson
- Division of Pediatric Rehabilitation Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
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8
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Maiese K. Cellular Metabolism: A Fundamental Component of Degeneration in the Nervous System. Biomolecules 2023; 13:816. [PMID: 37238686 PMCID: PMC10216724 DOI: 10.3390/biom13050816] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 05/05/2023] [Accepted: 05/10/2023] [Indexed: 05/28/2023] Open
Abstract
It is estimated that, at minimum, 500 million individuals suffer from cellular metabolic dysfunction, such as diabetes mellitus (DM), throughout the world. Even more concerning is the knowledge that metabolic disease is intimately tied to neurodegenerative disorders, affecting both the central and peripheral nervous systems as well as leading to dementia, the seventh leading cause of death. New and innovative therapeutic strategies that address cellular metabolism, apoptosis, autophagy, and pyroptosis, the mechanistic target of rapamycin (mTOR), AMP activated protein kinase (AMPK), growth factor signaling with erythropoietin (EPO), and risk factors such as the apolipoprotein E (APOE-ε4) gene and coronavirus disease 2019 (COVID-19) can offer valuable insights for the clinical care and treatment of neurodegenerative disorders impacted by cellular metabolic disease. Critical insight into and modulation of these complex pathways are required since mTOR signaling pathways, such as AMPK activation, can improve memory retention in Alzheimer's disease (AD) and DM, promote healthy aging, facilitate clearance of β-amyloid (Aß) and tau in the brain, and control inflammation, but also may lead to cognitive loss and long-COVID syndrome through mechanisms that can include oxidative stress, mitochondrial dysfunction, cytokine release, and APOE-ε4 if pathways such as autophagy and other mechanisms of programmed cell death are left unchecked.
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Affiliation(s)
- Kenneth Maiese
- Cellular and Molecular Signaling, New York, NY 10022, USA
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9
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Torrens JN, Hetzer SM, Evanson NK. Brief oxygen exposure after traumatic brain injury speeds recovery and promotes adaptive chronic endoplasmic reticulum stress responses. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.09.540060. [PMID: 37214818 PMCID: PMC10197672 DOI: 10.1101/2023.05.09.540060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Traumatic brain injury (TBI) is a major public health concern particularly in adolescents who have a higher mortality and incidence of visual pathway injury compared to adult patients. Likewise, we have found disparities between adult and adolescent TBI outcomes in rodents. Most interestingly, adolescents suffer a prolonged apneic period immediately post injury leading to higher mortality; so, we implemented a brief oxygen exposure paradigm to circumvent this increased mortality. Adolescent male mice experienced a closed-head weight-drop TBI then were exposed to 100% O 2 until normal breathing returned or recovered in room air. We followed mice for 7- and 30-days and assessed their optokinetic response; retinal ganglion cell loss; axonal degeneration; glial reactivity; and retinal ER stress protein levels. O 2 reduced adolescent mortality by 40%, improved post-injury visual acuity, and reduced axonal degeneration and gliosis in optic projection regions. ER stress protein expression was altered in injured mice, and mice given O 2 utilized different ER-stress pathways in a time dependent manner. Finally, O 2 exposure may be mediating these ER stress responses through regulation of the redox-sensitive ER folding protein ERO1α, which has been linked to a reduction in the toxic effects of free radicals in other animal models of ER stress.
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10
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Levin LA, Patrick C, Choudry NB, Sharif NA, Goldberg JL. Neuroprotection in neurodegenerations of the brain and eye: Lessons from the past and directions for the future. Front Neurol 2022; 13:964197. [PMID: 36034312 PMCID: PMC9412944 DOI: 10.3389/fneur.2022.964197] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 07/20/2022] [Indexed: 12/24/2022] Open
Abstract
BackgroundNeurological and ophthalmological neurodegenerative diseases in large part share underlying biology and pathophysiology. Despite extensive preclinical research on neuroprotection that in many cases bridges and unifies both fields, only a handful of neuroprotective therapies have succeeded clinically in either.Main bodyUnderstanding the commonalities among brain and neuroretinal neurodegenerations can help develop innovative ways to improve translational success in neuroprotection research and emerging therapies. To do this, analysis of why translational research in neuroprotection fails necessitates addressing roadblocks at basic research and clinical trial levels. These include optimizing translational approaches with respect to biomarkers, therapeutic targets, treatments, animal models, and regulatory pathways.ConclusionThe common features of neurological and ophthalmological neurodegenerations are useful for outlining a path forward that should increase the likelihood of translational success in neuroprotective therapies.
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Affiliation(s)
- Leonard A. Levin
- Departments of Ophthalmology and Visual Sciences, Neurology & Neurosurgery, McGill University, Montreal, QC, Canada
- *Correspondence: Leonard A. Levin
| | | | - Nozhat B. Choudry
- Global Alliances and External Research, Ophthalmology Innovation Center, Santen Inc., Emeryville, CA, United States
| | - Najam A. Sharif
- Global Alliances and External Research, Ophthalmology Innovation Center, Santen Inc., Emeryville, CA, United States
| | - Jeffrey L. Goldberg
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University, Palo Alto, CA, United States
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Maiese K. Pyroptosis, Apoptosis, and Autophagy: Critical Players of Inflammation and Cell Demise in the Nervous System. Curr Neurovasc Res 2022; 19:241-244. [PMID: 35909267 DOI: 10.2174/1567202619666220729093449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Almasieh M, Faris H, Levin LA. Pivotal roles for membrane phospholipids in axonal degeneration. Int J Biochem Cell Biol 2022; 150:106264. [PMID: 35868612 DOI: 10.1016/j.biocel.2022.106264] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 07/16/2022] [Accepted: 07/17/2022] [Indexed: 10/17/2022]
Abstract
Membrane phospholipids are critical components of several signaling pathways. Maintained in a variety of asymmetric distributions, their trafficking across the membrane can be induced by intra-, extra-, and intercellular events. A familiar example is the externalization of phosphatidylserine from the inner leaflet to the outer leaflet in apoptosis, inducing phagocytosis of the soma. Recently, it has been recognized that phospholipids in the axonal membrane may be a signal for axonal degeneration, regeneration, or other processes. This review focuses on key recent developments and areas for ongoing investigations. KEY FACTS: Phosphatidylserine externalization propagates along an axon after axonal injury and is delayed in the Wallerian degeneration slow (WldS) mutant. The ATP8A2 flippase mutant has spontaneous axonal degeneration. Microdomains of axonal degeneration in spheroid bodies have differential externalization of phosphatidylserine and phosphatidylethanolamine. Phospholipid trafficking could represent a mechanism for coordinated axonal degeneration and elimination, i.e. axoptosis, analogous to apoptosis of the cell body.
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Affiliation(s)
- Mohammadali Almasieh
- Department of Ophthalmology and Visual Sciences, McGill University, Montreal, Canada
| | - Hannah Faris
- Department of Ophthalmology and Visual Sciences, McGill University, Montreal, Canada
| | - Leonard A Levin
- Department of Ophthalmology and Visual Sciences, McGill University, Montreal, Canada; Department of Neurology and Neurosurgery, McGill University, Montreal, Canada.
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Yao S, Zhou Q, Yang M, Li Y, Jin X, Guo Q, Yang L, Qin F, Lei B. Multi-mtDNA Variants May Be a Factor Contributing to Mitochondrial Function Variety in the Skin-Derived Fibroblasts of Leber's Hereditary Optic Neuropathy Patients. Front Mol Neurosci 2022; 15:920221. [PMID: 35909448 PMCID: PMC9326446 DOI: 10.3389/fnmol.2022.920221] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 06/13/2022] [Indexed: 12/17/2022] Open
Abstract
Heterogeneity is a major feature of Leber's hereditary optic neuropathy (LHON) and has a significant impact on the manifestation and diagnosis of the disease. This study explored whether multiple variations in mitochondrial genes were associated with the heterogeneity, mainly phenotypic heterogeneity. Ophthalmic examinations were conducted in two probands with LHON with G11778A and multiple mitochondrial DNA gene (mtDNA) variants. Skin fibroblast cell lines were generated from patients and age- and sex-matched controls. ROS levels, mitochondrial membrane potential, cell energy respiration, and metabolic functions were measured. Flow cytometry and cell viability tests were performed to evaluate the cell apoptosis levels and fate. We found that cells with more mtDNA variants had higher ROS levels, lower mitochondrial membrane potential, and weaker respiratory function. Flow cytometry and cell viability testing showed that multiple mtDNA variants are associated with different levels of cell viability and apoptosis. In conclusion, we found that skin-derived fibroblast cells from G11778A LHON patients could be used as models for LHON research. Multi-mtDNA variants contribute to mitochondrial function variety, which may be associated with heterogeneity in patients with LHON.
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Affiliation(s)
- Shun Yao
- Henan Provincial People's Hospital, Zhengzhou University People's Hospital, Zhengzhou, China
- Henan Eye Institute, Henan Eye Hospital, Henan Provincial People's Hospital, Zhengzhou, China
| | - Qingru Zhou
- Henan Provincial People's Hospital, Zhengzhou University People's Hospital, Zhengzhou, China
- Henan Eye Institute, Henan Eye Hospital, Henan Provincial People's Hospital, Zhengzhou, China
- Academy of Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Mingzhu Yang
- Henan Provincial People's Hospital, Zhengzhou University People's Hospital, Zhengzhou, China
- Henan Eye Institute, Henan Eye Hospital, Henan Provincial People's Hospital, Zhengzhou, China
| | - Ya Li
- Henan Provincial People's Hospital, Zhengzhou University People's Hospital, Zhengzhou, China
- Henan Eye Institute, Henan Eye Hospital, Henan Provincial People's Hospital, Zhengzhou, China
| | - Xiuxiu Jin
- Henan Provincial People's Hospital, Zhengzhou University People's Hospital, Zhengzhou, China
- Henan Eye Institute, Henan Eye Hospital, Henan Provincial People's Hospital, Zhengzhou, China
| | - Qingge Guo
- Henan Provincial People's Hospital, Zhengzhou University People's Hospital, Zhengzhou, China
- Henan Eye Institute, Henan Eye Hospital, Henan Provincial People's Hospital, Zhengzhou, China
| | - Lin Yang
- Henan Provincial People's Hospital, Zhengzhou University People's Hospital, Zhengzhou, China
- Henan Eye Institute, Henan Eye Hospital, Henan Provincial People's Hospital, Zhengzhou, China
- Academy of Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Fangyuan Qin
- Henan Provincial People's Hospital, Zhengzhou University People's Hospital, Zhengzhou, China
| | - Bo Lei
- Henan Provincial People's Hospital, Zhengzhou University People's Hospital, Zhengzhou, China
- Henan Eye Institute, Henan Eye Hospital, Henan Provincial People's Hospital, Zhengzhou, China
- Academy of Medical Sciences, Zhengzhou University, Zhengzhou, China
- *Correspondence: Bo Lei
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Geva M, Gershoni-Emek N, Naia L, Ly P, Mota S, Rego AC, Hayden MR, Levin LA. Neuroprotection of retinal ganglion cells by the sigma-1 receptor agonist pridopidine in models of experimental glaucoma. Sci Rep 2021; 11:21975. [PMID: 34753986 PMCID: PMC8578336 DOI: 10.1038/s41598-021-01077-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 10/20/2021] [Indexed: 12/21/2022] Open
Abstract
Optic neuropathies such as glaucoma are characterized by retinal ganglion cell (RGC) degeneration and death. The sigma-1 receptor (S1R) is an attractive target for treating optic neuropathies as it is highly expressed in RGCs, and its absence causes retinal degeneration. Activation of the S1R exerts neuroprotective effects in models of retinal degeneration. Pridopidine is a highly selective and potent S1R agonist in clinical development. We show that pridopidine exerts neuroprotection of retinal ganglion cells in two different rat models of glaucoma. Pridopidine strongly binds melanin, which is highly expressed in the retina. This feature of pridopidine has implications to its ocular distribution, bioavailability, and effective dose. Mitochondria dysfunction is a key contributor to retinal ganglion cell degeneration. Pridopidine rescues mitochondrial function via activation of the S1R, providing support for the potential mechanism driving its neuroprotective effect in retinal ganglion cells.
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Affiliation(s)
| | | | - Luana Naia
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Department of Neurobiology, Care Science and Society, Karolinska Institutet, Stockholm, Sweden
| | - Philip Ly
- The Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Sandra Mota
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Ana Cristina Rego
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- FMUC-Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Michael R Hayden
- Prilenia Therapeutics, Herzliya, Israel
- The Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Leonard A Levin
- Department of Ophthalmology and Visual Sciences, McGill University, Montreal, Canada.
- Department of Neurology and Neurosurgery, McGill University, Montreal, Canada.
- Montreal Neurological Institute, McGill University, Montreal, Canada.
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15
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Yong Y, Hunter-Chang S, Stepanova E, Deppmann C. Axonal spheroids in neurodegeneration. Mol Cell Neurosci 2021; 117:103679. [PMID: 34678457 PMCID: PMC8742877 DOI: 10.1016/j.mcn.2021.103679] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 10/12/2021] [Accepted: 10/15/2021] [Indexed: 10/20/2022] Open
Abstract
Axonal spheroids are bubble-like biological features that form on most degenerating axons, yet little is known about their influence on degenerative processes. Their formation and growth has been observed in response to various degenerative triggers such as injury, oxidative stress, inflammatory factors, and neurotoxic molecules. They often contain cytoskeletal elements and organelles, and, depending on the pathological insult, can colocalize with disease-related proteins such as amyloid precursor protein (APP), ubiquitin, and motor proteins. Initial formation of axonal spheroids depends on the disruption of axonal and membrane tension governed by cytoskeleton structure and calcium levels. Shortly after spheroid formation, the engulfment signal phosphatidylserine (PS) is exposed on the outer leaflet of spheroid plasma membrane, suggesting an important role for axonal spheroids in phagocytosis and debris clearance during degeneration. Spheroids can grow until they rupture, allowing pro-degenerative factors to exit the axon into extracellular space and accelerating neurodegeneration. Though much remains to be discovered in this area, axonal spheroid research promises to lend insight into the etiologies of neurodegenerative disease, and may be an important target for therapeutic intervention. This review summarizes over 100 years of work, describing what is known about axonal spheroid structure, regulation and function.
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Affiliation(s)
- Yu Yong
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA
| | - Sarah Hunter-Chang
- Neuroscience Graduate Program, University of Virginia, Charlottesville, VA 22903, USA
| | - Ekaterina Stepanova
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA
| | - Christopher Deppmann
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA; Neuroscience Graduate Program, University of Virginia, Charlottesville, VA 22903, USA.
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16
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Faris H, Almasieh M, Levin LA. Axonal degeneration induces distinct patterns of phosphatidylserine and phosphatidylethanolamine externalization. Cell Death Discov 2021; 7:247. [PMID: 34535640 PMCID: PMC8448818 DOI: 10.1038/s41420-021-00641-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/17/2021] [Accepted: 08/26/2021] [Indexed: 11/28/2022] Open
Abstract
Axonal degeneration is a common feature of multiple neurodegenerative diseases, yet the mechanisms underlying its various manifestations are incompletely understood. We previously demonstrated that axonal degeneration is associated with externalization of phosphatidylserine (PS), which precedes morphological evidence of degeneration, is redox-sensitive, and is delayed in Wallerian degeneration slow (WldS) mutant animals. Phosphatidylethanolamine (PE) is the other major membrane phospholipid in the inner leaflet of the cell membrane, and given that PS signals apoptosis, phagocytosis, and degeneration, we hypothesized that PS and PE membrane dynamics play distinct roles in axonal degeneration. To test this hypothesis, axonal degeneration was induced with calcium ionophores in postnatal rat retinal ganglion cells, and PS- and PE-specific fluorescent probes used to measure their externalization over time. In untreated cells, cell-surface PS was prominent in the cell body alone. Elevation of intracellular calcium with calcium ionophores resulted in significantly increased levels of PS externalization in the cell body, axon, and axon growth cone. Unlike PS, cell-surface PE was diffusely distributed in untreated cells, with comparable levels across the soma, axons, and axon terminals. After exposure to calcium ionophores, PE externalization significantly increased in the cell body and axon. Elevated intracellular calcium also resulted in the formation of axonal blebs which exclusively contained externalized PS, but not PE. Together, these results indicated distinct patterns of externalized PS and PE in normal and degenerating neurons, suggesting a differential role for these phospholipids in transducing neuronal injury.
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Affiliation(s)
- Hannah Faris
- Department of Ophthalmology and Visual Sciences, McGill University, Montreal, Canada
| | - Mohammadali Almasieh
- Department of Ophthalmology and Visual Sciences, McGill University, Montreal, Canada
| | - Leonard A Levin
- Department of Ophthalmology and Visual Sciences, McGill University, Montreal, Canada. .,Department of Neurology and Neurosurgery, McGill University, Montreal, Canada.
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17
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Maiese K. Nicotinamide as a Foundation for Treating Neurodegenerative Disease and Metabolic Disorders. Curr Neurovasc Res 2021; 18:134-149. [PMID: 33397266 PMCID: PMC8254823 DOI: 10.2174/1567202617999210104220334] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 12/18/2020] [Accepted: 12/22/2020] [Indexed: 02/06/2023]
Abstract
Neurodegenerative disorders impact more than one billion individuals worldwide and are intimately tied to metabolic disease that can affect another nine hundred individuals throughout the globe. Nicotinamide is a critical agent that may offer fruitful prospects for neurodegenerative diseases and metabolic disorders, such as diabetes mellitus. Nicotinamide protects against multiple toxic environments that include reactive oxygen species exposure, anoxia, excitotoxicity, ethanolinduced neuronal injury, amyloid (Aß) toxicity, age-related vascular disease, mitochondrial dysfunction, insulin resistance, excess lactate production, and loss of glucose homeostasis with pancreatic β-cell dysfunction. However, nicotinamide offers cellular protection in a specific concentration range, with dosing outside of this range leading to detrimental effects. The underlying biological pathways of nicotinamide that involve the silent mating type information regulation 2 homolog 1 (Saccharomyces cerevisiae) (SIRT1), the mechanistic target of rapamycin (mTOR), AMP activated protein kinase (AMPK), and mammalian forkhead transcription factors (FoxOs) may offer insight for the clinical translation of nicotinamide into a safe and efficacious therapy through the modulation of oxidative stress, apoptosis, and autophagy. Nicotinamide is a highly promising target for the development of innovative strategies for neurodegenerative disorders and metabolic disease, but the benefits of this foundation depend greatly on gaining a further understanding of nicotinamide's complex biology.
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Affiliation(s)
- Kenneth Maiese
- Cellular and Molecular Signaling, New York, New York 10022
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18
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Abstract
The global increase in lifespan noted not only in developed nations, but also in large developing countries parallels an observed increase in a significant number of non-communicable diseases, most notable neurodegenerative disorders. Neurodegenerative disorders present a number of challenges for treatment options that do not resolve disease progression. Furthermore, it is believed by the year 2030, the services required to treat cognitive disorders in the United States alone will exceed $2 trillion annually. Mammalian forkhead transcription factors, silent mating type information regulation 2 homolog 1 (Saccharomyces cerevisiae), the mechanistic target of rapamycin, and the pathways of autophagy and apoptosis offer exciting avenues to address these challenges by focusing upon core cellular mechanisms that may significantly impact nervous system disease. These pathways are intimately linked such as through cell signaling pathways involving protein kinase B and can foster, sometimes in conjunction with trophic factors, enhanced neuronal survival, reduction in toxic intracellular accumulations, and mitochondrial stability. Feedback mechanisms among these pathways also exist that can oversee reparative processes in the nervous system. However, mammalian forkhead transcription factors, silent mating type information regulation 2 homolog 1, mechanistic target of rapamycin, and autophagy can lead to cellular demise under some scenarios that may be dependent upon the precise cellular environment, warranting future studies to effectively translate these core pathways into successful clinical treatment strategies for neurodegenerative disorders.
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Affiliation(s)
- Kenneth Maiese
- Cellular and Molecular Signaling New York, New York, NY, USA
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19
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Sapar ML, Ji H, Wang B, Poe AR, Dubey K, Ren X, Ni JQ, Han C. Phosphatidylserine Externalization Results from and Causes Neurite Degeneration in Drosophila. Cell Rep 2020; 24:2273-2286. [PMID: 30157423 PMCID: PMC6174084 DOI: 10.1016/j.celrep.2018.07.095] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 05/25/2018] [Accepted: 07/27/2018] [Indexed: 01/20/2023] Open
Abstract
Phagocytic clearance of degenerating dendrites or axons is critical for maintaining tissue homeostasis and preventing neuroinflammation. Externalized phosphatidylserine (PS) has been postulated to be an ‘‘eat-me’’ signal allowing recognition of degenerating neurites by phagocytes. Here we show that in Drosophila, PS is dynamically exposed on degenerating dendrites during developmental pruning and after physical injury, but PS exposure is suppressed when dendrite degeneration is genetically blocked. Ectopic PS exposure via phospholipid flippase knockout and scramblase overexpression induced PS exposure preferentially at distal dendrites and caused distinct modes of neurite loss that differ in larval sensory dendrites and in adult olfactory axons. Surprisingly, extracellular lactadherin that lacks the integrin-interaction domain induced phagocyte-dependent degeneration of PS-exposing dendrites, revealing an unidentified bridging function that potentiates phagocytes. Our findings establish a direct causal relationship between PS exposure and neurite degeneration in vivo. Using in vivo phosphatidylserine (PS) sensors, Sapar et al. reveal dynamic patterns of PS exposure on degenerating dendrites in Drosophila. Flippase knockout and scramblase overexpression lead to ectopic PS exposure on distal dendrites and context-dependent neurite degeneration. Lactadherin potentiates phagocytes to destruct PS-exposing dendrites, independent of its integrin-interaction domain.
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Affiliation(s)
- Maria L Sapar
- Weill Institute for Cell and Molecular Biology, Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Hui Ji
- Weill Institute for Cell and Molecular Biology, Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Bei Wang
- Weill Institute for Cell and Molecular Biology, Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Amy R Poe
- Weill Institute for Cell and Molecular Biology, Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Kush Dubey
- Weill Institute for Cell and Molecular Biology, Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Xingjie Ren
- Gene Regulatory Lab, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Jian-Quan Ni
- Gene Regulatory Lab, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Chun Han
- Weill Institute for Cell and Molecular Biology, Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
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20
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Faiq MA, Wollstein G, Schuman JS, Chan KC. Cholinergic nervous system and glaucoma: From basic science to clinical applications. Prog Retin Eye Res 2019; 72:100767. [PMID: 31242454 PMCID: PMC6739176 DOI: 10.1016/j.preteyeres.2019.06.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 06/19/2019] [Accepted: 06/21/2019] [Indexed: 02/08/2023]
Abstract
The cholinergic system has a crucial role to play in visual function. Although cholinergic drugs have been a focus of attention as glaucoma medications for reducing eye pressure, little is known about the potential modality for neuronal survival and/or enhancement in visual impairments. Citicoline, a naturally occurring compound and FDA approved dietary supplement, is a nootropic agent that is recently demonstrated to be effective in ameliorating ischemic stroke, traumatic brain injury, Parkinson's disease, Alzheimer's disease, cerebrovascular diseases, memory disorders and attention-deficit/hyperactivity disorder in both humans and animal models. The mechanisms of its action appear to be multifarious including (i) preservation of cardiolipin, sphingomyelin, and arachidonic acid contents of phosphatidylcholine and phosphatidylethanolamine, (ii) restoration of phosphatidylcholine, (iii) stimulation of glutathione synthesis, (iv) lowering glutamate concentrations and preventing glutamate excitotoxicity, (v) rescuing mitochondrial function thereby preventing oxidative damage and onset of neuronal apoptosis, (vi) synthesis of myelin leading to improvement in neuronal membrane integrity, (vii) improving acetylcholine synthesis and thereby reducing the effects of mental stress and (viii) preventing endothelial dysfunction. Such effects have vouched for citicoline as a neuroprotective, neurorestorative and neuroregenerative agent. Retinal ganglion cells are neurons with long myelinated axons which provide a strong rationale for citicoline use in visual pathway disorders. Since glaucoma is a form of neurodegeneration involving retinal ganglion cells, citicoline may help ameliorate glaucomatous damages in multiple facets. Additionally, trans-synaptic degeneration has been identified in humans and experimental models of glaucoma suggesting the cholinergic system as a new brain target for glaucoma management and therapy.
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Affiliation(s)
- Muneeb A Faiq
- Department of Ophthalmology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, United States
| | - Gadi Wollstein
- Department of Ophthalmology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, United States
| | - Joel S Schuman
- Department of Ophthalmology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, United States
| | - Kevin C Chan
- Department of Ophthalmology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, United States; Department of Radiology, New York University (NYU) School of Medicine, NYU Langone Health, New York, NY, United States; Center for Neural Science, Faculty of Arts and Science, New York University, New York, NY, United States.
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21
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Hirahara Y, Wakabayashi T, Koike T, Gamo K, Yamada H. Change in phospholipid species of retinal layer in traumatic optic neuropathy model. J Neurosci Res 2019; 98:325-337. [PMID: 31385342 DOI: 10.1002/jnr.24500] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 06/11/2019] [Accepted: 07/03/2019] [Indexed: 12/17/2022]
Abstract
Injured optic nerves induce death in almost all retinal ganglion cells (RGC) and cause a loss of axons. To date, we have studied injured RGC axon regeneration by using a traumatic optic nerve injury (TONI) rodent model, and we revealed that axonal regeneration is induced by the graft of an autologous peripheral nerve. The efficient approach to the regeneration of axons thus needs an environmental adjustment of RGC. However, the RGC environment induced by TONI remains unknown. Here, we analyzed female and male C57BL/6 mouse retinal tissue alterations in detail after TONI and focused on the major phospholipid species that are enriched in the whole retina. Reactive astrocyte accumulation, glia scar formation, and demyelination were observed in the injured optic nerve area, while RGC cell death, astrocyte accumulation, and Glial fibrillary acidic protein (GFAP) positive Müller cell increases were detected in the retinal layer. Furthermore, phosphatidylinositol (PI) 18:0/20:4 was localized to three nuclear layer structures: the ganglion cell layer (GCL), the inner nuclear layer (INL), and the outer nuclear layer (ONL) in control retina; however, the localization of 18:0/20:4 PI in TONI was disturbed. Meanwhile, phosphatidylserine (PS) 18:0/22:6 showed that the expression was specifically in the inner plexiform layer (IPL) with similar signal intensity in both cases. Other PS species and phosphatidylethanolamine (PE) were differentially localized in the retinal layer; however, the expressions of PE including docosahexaenoic acid (DHA) were affected by TONI. These results suggest that not only GCL but also other retinal layers were influenced by TONI.
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Affiliation(s)
- Yukie Hirahara
- Department of Anatomy, Kansai Medical University, Osaka, Japan
| | | | - Taro Koike
- Department of Anatomy, Kansai Medical University, Osaka, Japan
| | - Keizo Gamo
- Department of Anatomy, Kansai Medical University, Osaka, Japan
| | - Hisao Yamada
- Department of Anatomy, Kansai Medical University, Osaka, Japan
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22
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Sapar ML, Han C. Die in pieces: How Drosophila sheds light on neurite degeneration and clearance. J Genet Genomics 2019; 46:187-199. [PMID: 31080046 PMCID: PMC6541534 DOI: 10.1016/j.jgg.2019.03.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 03/24/2019] [Accepted: 03/26/2019] [Indexed: 01/08/2023]
Abstract
Dendrites and axons are delicate neuronal membrane extensions that undergo degeneration after physical injuries. In neurodegenerative diseases, they often degenerate prior to neuronal death. Understanding the mechanisms of neurite degeneration has been an intense focus of neurobiology research in the last two decades. As a result, many discoveries have been made in the molecular pathways that lead to neurite degeneration and the cell-cell interactions responsible for the subsequent clearance of neuronal debris. Drosophila melanogaster has served as a prime in vivo model system for identifying and characterizing the key molecular players in neurite degeneration, thanks to its genetic tractability and easy access to its nervous system. The knowledge learned in the fly provided targets and fuel for studies in other model systems that have further enhanced our understanding of neurodegeneration. In this review, we will introduce the experimental systems developed in Drosophila to investigate injury-induced neurite degeneration, and then discuss the biological pathways that drive degeneration. We will also cover what is known about the mechanisms of how phagocytes recognize and clear degenerating neurites, and how recent findings in this area enhance our understanding of neurodegenerative disease pathology.
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Affiliation(s)
- Maria L Sapar
- Weill Institute for Cell and Molecular Biology, Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14853, USA
| | - Chun Han
- Weill Institute for Cell and Molecular Biology, Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14853, USA.
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23
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Wang RR, Li CF, Wang DZ, Zhang CW, Liu GX. c-Jun N-terminal kinase 3 deficiency protects axotomized retinal ganglion cells via affecting mitochondria involved apoptosis pathway. Int J Ophthalmol 2019; 12:30-37. [PMID: 30662837 PMCID: PMC6326936 DOI: 10.18240/ijo.2019.01.05] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 11/05/2018] [Indexed: 11/23/2022] Open
Abstract
AIM To illustrate the isoform-specific role and mechanism of c-Jun N-terminal kinases (JNKs) in mouse optic nerve axotomy induced neurotrauma. METHODS We firstly investigated the expression of JNK1, JNK2, and JNK3 in the retinal ganglion cells (RGCs) by double-immunofluorescent staining. Then we created optic nerve axotomy model in wild type as well as JNK1, JNK2, JNK3, isoform specific gene deficiency mice. With that, we checked the protein expression profile of JNKs and its active form, and quantified the survival RGCs number by immunofluorescence staining. We further explored the molecules underlying isoform specific protective effect by real-time polymerase chain reaction (PCR) and Western blotting assay. RESULTS We found that all the three isoforms of JNKs were expressed in the RGCs. Deficiency of JNK3, but not JNK1 or JNK2, significantly alleviated optic nerve axotomy induced RGCs apoptosis. We further established that expression of Noxa, a pro-apoptotic member of BH3 family, was significantly suppressed only in JNK3 gene deficiency mice. But tumor necrosis factor receptor 1 (TNFR1) and Fas, two key modulators of death receptor mediated apoptosis pathway, did not display obvious change in the expression. CONCLUSION It is suggested that mitochondria mediated apoptosis, but not death receptor mediated apoptosis got involved in the JNK3 gene deficiency induced RGCs protection. Our study provides a novel insight into the isoform-specific role of JNKs in neurotrauma and indicates some cues for its therapeutics.
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Affiliation(s)
- Rong-Rong Wang
- Qingdao University, Qingdao 266000, Shandong Province, China
- Department of Ophthalmology, Jimo Traditional Chinese Medicine Hospital, Qingdao 266200, Shandong Province, China
| | - Cheng-Fang Li
- Department of Ophthalmology, Affiliated Qingdao Hiser Hospital of Qingdao University, Qingdao 266000, Shandong Province, China
| | - De-Zu Wang
- Department of Ophthalmology, Jimo Traditional Chinese Medicine Hospital, Qingdao 266200, Shandong Province, China
| | - Cheng-Wu Zhang
- Institute of Advanced Materials, Nanjing Tech University, Nanjing 211800, Jiangsu Province, China
| | - Gui-Xiang Liu
- Department of Ophthalmology, Affiliated Hospital of the Medical College of Qingdao University, Qingdao 266000, Shandong Province, China
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24
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Neumann B, Linton C, Giordano-Santini R, Hilliard MA. Axonal fusion: An alternative and efficient mechanism of nerve repair. Prog Neurobiol 2018; 173:88-101. [PMID: 30500382 DOI: 10.1016/j.pneurobio.2018.11.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 11/22/2018] [Accepted: 11/26/2018] [Indexed: 02/07/2023]
Abstract
Injuries to the nervous system can cause lifelong morbidity due to the disconnect that occurs between nerve cells and their cellular targets. Re-establishing these lost connections is the ultimate goal of endogenous regenerative mechanisms, as well as those induced by exogenous manipulations in a laboratory or clinical setting. Reconnection between severed neuronal fibers occurs spontaneously in some invertebrate species and can be induced in mammalian systems. This process, known as axonal fusion, represents a highly efficient means of repair after injury. Recent progress has greatly enhanced our understanding of the molecular control of axonal fusion, demonstrating that the machinery required for the engulfment of apoptotic cells is repurposed to mediate the reconnection between severed axon fragments, which are subsequently merged by fusogen proteins. Here, we review our current understanding of naturally occurring axonal fusion events, as well as those being ectopically produced with the aim of achieving better clinical outcomes.
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Affiliation(s)
- Brent Neumann
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne VIC 3800, Australia.
| | - Casey Linton
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Rosina Giordano-Santini
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Massimo A Hilliard
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia.
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25
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Alqawlaq S, Flanagan JG, Sivak JM. All roads lead to glaucoma: Induced retinal injury cascades contribute to a common neurodegenerative outcome. Exp Eye Res 2018; 183:88-97. [PMID: 30447198 DOI: 10.1016/j.exer.2018.11.005] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 11/02/2018] [Accepted: 11/06/2018] [Indexed: 11/25/2022]
Abstract
Glaucoma describes a distinct optic neuropathy with complex etiology and a variety of associated risk factors, but with similar pathological endpoints. Risk factors such as age, increased intraocular pressure (IOP), low mean arterial pressure, and autoimmune disease, can all be associated with death of retinal ganglion cells (RGCs) and optic nerve head remodeling. Today, IOP management remains the standard of care, even though IOP elevation is not pathognomonic of glaucoma, and patients can continue to lose vision despite effective IOP control. A contemporary view of glaucoma as a complex, neurodegenerative disease has developed, along with the recognition of a need for new disease modifying retinal treatment strategies and improved outcomes. However, the distinction between risk factors triggering the disease process and retinal injury responses is not always clear. In this review, we attempt to distinguish between the various triggers, and their association with subsequent key RGC injury mechanisms. We propose that distinct glaucomatous risk factors result in similar retinal and optic nerve injury cascades, including oxidative and metabolic stress, glial reactivity, and altered inflammatory responses, which induce common molecular signals to induce RGC apoptosis. This organization forms a coherent disease framework and presents conserved targets for therapeutic intervention that are not limited to specific risk factors.
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Affiliation(s)
- Samih Alqawlaq
- Department of Vision Science, Krembil Research Institute, University Health Network, Toronto, ON, Canada; Vision Science Research Program, Ophthalmology and Vision Science, University of Toronto, Toronto, ON, Canada; Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - John G Flanagan
- School of Optometry and Vision Science Program, University of California at Berkeley, Berkeley, CA, USA
| | - Jeremy M Sivak
- Department of Vision Science, Krembil Research Institute, University Health Network, Toronto, ON, Canada; Vision Science Research Program, Ophthalmology and Vision Science, University of Toronto, Toronto, ON, Canada; Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.
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26
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Phosphatidylserine is a marker for axonal debris engulfment but its exposure can be decoupled from degeneration. Cell Death Dis 2018; 9:1116. [PMID: 30389906 PMCID: PMC6214901 DOI: 10.1038/s41419-018-1155-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 09/25/2018] [Accepted: 10/08/2018] [Indexed: 02/08/2023]
Abstract
Apoptotic cells expose Phosphatidylserine (PS), that serves as an “eat me” signal for engulfing cells. Previous studies have shown that PS also marks degenerating axonsduring developmental pruning or in response to insults (Wallerian degeneration), but the pathways that control PS exposure on degenerating axons are largely unknown. Here, we used a series of in vitro assays to systematically explore the regulation of PS exposure during axonal degeneration. Our results show that PS exposure is regulated by the upstream activators of axonal pruning and Wallerian degeneration. However, our investigation of signaling further downstream revealed divergence between axon degeneration and PS exposure. Importantly, elevation of the axonal energetic status hindered PS exposure, while inhibition of mitochondrial activity caused PS exposure, without degeneration. Overall, our results suggest that the levels of PS on the outer axonal membrane can be dissociated from the degeneration process and that the axonal energetic status plays a key role in the regulation of PS exposure.
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27
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The mechanistic target of rapamycin (mTOR) and the silent mating-type information regulation 2 homolog 1 (SIRT1): oversight for neurodegenerative disorders. Biochem Soc Trans 2018. [PMID: 29523769 DOI: 10.1042/bst20170121] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
As a result of the advancing age of the global population and the progressive increase in lifespan, neurodegenerative disorders continue to increase in incidence throughout the world. New strategies for neurodegenerative disorders involve the novel pathways of the mechanistic target of rapamycin (mTOR) and the silent mating-type information regulation 2 homolog 1 (Saccharomyces cerevisiae) (SIRT1) that can modulate pathways of apoptosis and autophagy. The pathways of mTOR and SIRT1 are closely integrated. mTOR forms the complexes mTOR Complex 1 and mTOR Complex 2 and can impact multiple neurodegenerative disorders that include Alzheimer's disease, Huntington's disease, and Parkinson's disease. SIRT1 can control stem cell proliferation, block neuronal injury through limiting programmed cell death, drive vascular cell survival, and control clinical disorders that include dementia and retinopathy. It is important to recognize that oversight of programmed cell death by mTOR and SIRT1 requires a fine degree of precision to prevent the progression of neurodegenerative disorders. Additional investigations and insights into these pathways should offer effective and safe treatments for neurodegenerative disorders.
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Maiese K. Novel Treatment Strategies for the Nervous System: Circadian Clock Genes, Non-coding RNAs, and Forkhead Transcription Factors. Curr Neurovasc Res 2018; 15:81-91. [PMID: 29557749 PMCID: PMC6021214 DOI: 10.2174/1567202615666180319151244] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Revised: 01/23/2018] [Accepted: 02/07/2018] [Indexed: 12/16/2022]
Abstract
BACKGROUND With the global increase in lifespan expectancy, neurodegenerative disorders continue to affect an ever-increasing number of individuals throughout the world. New treatment strategies for neurodegenerative diseases are desperately required given the lack of current treatment modalities. METHODS Here, we examine novel strategies for neurodegenerative disorders that include circadian clock genes, non-coding Ribonucleic Acids (RNAs), and the mammalian forkhead transcription factors of the O class (FoxOs). RESULTS Circadian clock genes, non-coding RNAs, and FoxOs offer exciting prospects to potentially limit or remove the significant disability and death associated with neurodegenerative disorders. Each of these pathways has an intimate relationship with the programmed death pathways of autophagy and apoptosis and share a common link to the silent mating type information regulation 2 homolog 1 (Saccharomyces cerevisiae) (SIRT1) and the mechanistic target of rapamycin (mTOR). Circadian clock genes are necessary to modulate autophagy, limit cognitive loss, and prevent neuronal injury. Non-coding RNAs can control neuronal stem cell development and neuronal differentiation and offer protection against vascular disease such as atherosclerosis. FoxOs provide exciting prospects to block neuronal apoptotic death and to activate pathways of autophagy to remove toxic accumulations in neurons that can lead to neurodegenerative disorders. CONCLUSION Continued work with circadian clock genes, non-coding RNAs, and FoxOs can offer new prospects and hope for the development of vital strategies for the treatment of neurodegenerative diseases. These innovative investigative avenues have the potential to significantly limit disability and death from these devastating disorders.
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Affiliation(s)
- Kenneth Maiese
- Cellular and Molecular Signaling, Newark, New Jersey 07101
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Rapino C, Tortolani D, Scipioni L, Maccarrone M. Neuroprotection by (endo)Cannabinoids in Glaucoma and Retinal Neurodegenerative Diseases. Curr Neuropharmacol 2018; 16:959-970. [PMID: 28738764 PMCID: PMC6120105 DOI: 10.2174/1570159x15666170724104305] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 07/14/2017] [Accepted: 07/21/2017] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Emerging neuroprotective strategies are being explored to preserve the retina from degeneration, that occurs in eye pathologies like glaucoma, diabetic retinopathy, age-related macular degeneration, and retinitis pigmentosa. Incidentally, neuroprotection of retina is a defending mechanism designed to prevent or delay neuronal cell death, and to maintain neural function following an initial insult, thus avoiding loss of vision. METHODS Numerous studies have investigated potential neuroprotective properties of plant-derived phytocannabinoids, as well as of their endogenous counterparts collectively termed endocannabinoids (eCBs), in several degenerative diseases of the retina. eCBs are a group of neuromodulators that, mainly by activating G protein-coupled type-1 and type-2 cannabinoid (CB1 and CB2) receptors, trigger multiple signal transduction cascades that modulate central and peripheral cell functions. A fine balance between biosynthetic and degrading enzymes that control the right concentration of eCBs has been shown to provide neuroprotection in traumatic, ischemic, inflammatory and neurotoxic damage of the brain. RESULTS Since the existence of eCBs and their binding receptors was documented in the retina of numerous species (from fishes to primates), their involvement in the visual processing has been demonstrated, more recently with a focus on retinal neurodegeneration and neuroprotection. CONCLUSION The aim of this review is to present a modern view of the endocannabinoid system, in order to discuss in a better perspective available data from preclinical studies on the use of eCBs as new neuroprotective agents, potentially useful to prevent glaucoma and retinal neurodegenerative diseases.
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Affiliation(s)
- Cinzia Rapino
- Address correspondence to these authors at the Faculty of Veterinary Medicine, University of Teramo, 64100 Teramo, Italy; Tel: +39 0861 266842;, E-mail: and the Department of Medicine, Campus Bio-Medico University of Rome, 00128 Rome, Italy; Tel: +39 06 225419169;, E-mail:
| | | | | | - Mauro Maccarrone
- Address correspondence to these authors at the Faculty of Veterinary Medicine, University of Teramo, 64100 Teramo, Italy; Tel: +39 0861 266842;, E-mail: and the Department of Medicine, Campus Bio-Medico University of Rome, 00128 Rome, Italy; Tel: +39 06 225419169;, E-mail:
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