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Cullen PF, Gammerdinger WJ, Ho Sui SJ, Mazumder AG, Sun D. Transcriptional profiling of retinal astrocytes identifies a specific marker and points to functional specialization. Glia 2024. [PMID: 38785355 DOI: 10.1002/glia.24571] [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: 01/03/2024] [Revised: 04/19/2024] [Accepted: 05/13/2024] [Indexed: 05/25/2024]
Abstract
Astrocyte heterogeneity is an increasingly prominent research topic, and studies in the brain have demonstrated substantial variation in astrocyte form and function, both between and within regions. In contrast, retinal astrocytes are not well understood and remain incompletely characterized. Along with optic nerve astrocytes, they are responsible for supporting retinal ganglion cell axons and an improved understanding of their role is required. We have used a combination of microdissection and Ribotag immunoprecipitation to isolate ribosome-associated mRNA from retinal astrocytes and investigate their transcriptome, which we also compared to astrocyte populations in the optic nerve. Astrocytes from these regions are transcriptionally distinct, and we identified retina-specific astrocyte genes and pathways. Moreover, although they share much of the "classical" gene expression patterns of astrocytes, we uncovered unexpected variation, including in genes related to core astrocyte functions. We additionally identified the transcription factor Pax8 as a highly specific marker of retinal astrocytes and demonstrated that these astrocytes populate not only the retinal surface, but also the prelaminar region at the optic nerve head. These findings are likely to contribute to a revised understanding of the role of astrocytes in the retina.
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Affiliation(s)
- Paul F Cullen
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, USA
| | - William J Gammerdinger
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Shannan J Ho Sui
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Arpan Guha Mazumder
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, USA
| | - Daniel Sun
- Department of Ophthalmology, Schepens Eye Research Institute of Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, USA
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2
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Xu H, Zhang LB, Luo YY, Wang L, Zhang YP, Chen PQ, Ba XY, Han J, Luo H. Synaptotagmins family affect glucose transport in retinal pigment epithelial cells through their ubiquitination-mediated degradation and glucose transporter-1 regulation. World J Diabetes 2024; 15:958-976. [PMID: 38766439 PMCID: PMC11099358 DOI: 10.4239/wjd.v15.i5.958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 01/22/2024] [Accepted: 03/11/2024] [Indexed: 05/10/2024] Open
Abstract
BACKGROUND Synaptotagmins (SYTs) are a family of 17 membrane transporters that function as calcium ion sensors during the release of Ca2+-dependent neurotransmitters and hormones. However, few studies have reported whether members of the SYT family play a role in glucose uptake in diabetic retinopathy (DR) through Ca2+/glucose transporter-1 (GLUT1) and the possible regulatory mechanism of SYTs. AIM To elucidate the role of the SYT family in the regulation of glucose transport in retinal pigment epithelial cells and explore its potential as a therapeutic target for the clinical management of DR. METHODS DR was induced by streptozotocin in C57BL/6J mice and by high glucose medium in human retinal pigment epithelial cells (ARPE-19). Bioinformatics analysis, reverse transcriptase-polymerase chain reaction, Western blot, flow cytometry, ELISA, HE staining, and TUNEL staining were used for analysis. RESULTS Six differentially expressed proteins (SYT2, SYT3, SYT4, SYT7, SYT11, and SYT13) were found between the DR and control groups, and SYT4 was highly expressed. Hyperglycemia induces SYT4 overexpression, manipulates Ca2+ influx to induce GLUT1 fusion with the plasma membrane, promotes abnormal expression of the glucose transporter GLUT1 and excessive glucose uptake, induces ARPE-19 cell apoptosis, and promotes DR progression. Parkin deficiency inhibits the proteasomal degradation of SYT4 in DR, resulting in SYT4 accumulation and enhanced GLUT1 fusion with the plasma membrane, and these effects were blocked by oe-Parkin treatment. Moreover, dysregulation of the myelin transcription factor 1 (Myt1)-induced transcription of SYT4 in DR further activated the SYT4-mediated stimulus-secretion coupling process, and this process was inhibited in the oe-MYT1-treated group. CONCLUSION Our study reveals the key role of SYT4 in regulating glucose transport in retinal pigment epithelial cells during the pathogenesis of DR and the underlying mechanism and suggests potential therapeutic targets for clinical DR.
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Affiliation(s)
- Hong Xu
- Department of Ophthalmology, The People’s Hospital of Chuxiong Yi Autonomous Prefecture & The Fourth Affiliated Hospital of Dali University, Chuxiong Yi Autonomous Prefecture 675000, Yunnan Province, China
| | - Li-Bo Zhang
- Department of Ophthalmology, The People’s Hospital of Chuxiong Yi Autonomous Prefecture & The Fourth Affiliated Hospital of Dali University, Chuxiong Yi Autonomous Prefecture 675000, Yunnan Province, China
| | - Yi-Yi Luo
- Precision Medicine Center of Chuxiong Yi Autonomous Prefecture, The People’s Hospital of Chuxiong Yi Autonomous Prefecture & The Fourth Affiliated Hospital of Dali University, Chuxiong Yi Autonomous Prefecture 675000, Yunnan Province, China
| | - Ling Wang
- Department of Endocrinology, The People’s Hospital of Chuxiong Yi Autonomous Prefecture & The Fourth Affiliated Hospital of Dali University, Chuxiong Yi Autonomous Prefecture 675000, Yunnan Province, China
| | - Ye-Pin Zhang
- Department of Pathology, The People’s Hospital of Chuxiong Yi Autonomous Prefecture & The Fourth Affiliated Hospital of Dali University, Chuxiong Yi Autonomous Prefecture 675000, Yunnan Province, China
| | - Pei-Qi Chen
- Department of Endocrinology, The People’s Hospital of Chuxiong Yi Autonomous Prefecture & The Fourth Affiliated Hospital of Dali University, Chuxiong Yi Autonomous Prefecture 675000, Yunnan Province, China
| | - Xue-Ying Ba
- Precision Medicine Center of Chuxiong Yi Autonomous Prefecture, The People’s Hospital of Chuxiong Yi Autonomous Prefecture & The Fourth Affiliated Hospital of Dali University, Chuxiong Yi Autonomous Prefecture 675000, Yunnan Province, China
| | - Jian Han
- Precision Medicine Center of Chuxiong Yi Autonomous Prefecture, The People’s Hospital of Chuxiong Yi Autonomous Prefecture & The Fourth Affiliated Hospital of Dali University, Chuxiong Yi Autonomous Prefecture 675000, Yunnan Province, China
| | - Heng Luo
- Department of Ophthalmology, The People’s Hospital of Chuxiong Yi Autonomous Prefecture & The Fourth Affiliated Hospital of Dali University, Chuxiong Yi Autonomous Prefecture 675000, Yunnan Province, China
- Precision Medicine Center of Chuxiong Yi Autonomous Prefecture, The People’s Hospital of Chuxiong Yi Autonomous Prefecture & The Fourth Affiliated Hospital of Dali University, Chuxiong Yi Autonomous Prefecture 675000, Yunnan Province, China
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Chen Y, Zizmare L, Calbiague V, Wang L, Yu S, Herberg FW, Schmachtenberg O, Paquet-Durand F, Trautwein C. Retinal metabolism displays evidence for uncoupling of glycolysis and oxidative phosphorylation via Cori-, Cahill-, and mini-Krebs-cycle. eLife 2024; 12:RP91141. [PMID: 38739438 PMCID: PMC11090511 DOI: 10.7554/elife.91141] [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] [Indexed: 05/14/2024] Open
Abstract
The retina consumes massive amounts of energy, yet its metabolism and substrate exploitation remain poorly understood. Here, we used a murine explant model to manipulate retinal energy metabolism under entirely controlled conditions and utilised 1H-NMR spectroscopy-based metabolomics, in situ enzyme detection, and cell viability readouts to uncover the pathways of retinal energy production. Our experimental manipulations resulted in varying degrees of photoreceptor degeneration, while the inner retina and retinal pigment epithelium were essentially unaffected. This selective vulnerability of photoreceptors suggested very specific adaptations in their energy metabolism. Rod photoreceptors were found to rely strongly on oxidative phosphorylation, but only mildly on glycolysis. Conversely, cone photoreceptors were dependent on glycolysis but insensitive to electron transport chain decoupling. Importantly, photoreceptors appeared to uncouple glycolytic and Krebs-cycle metabolism via three different pathways: (1) the mini-Krebs-cycle, fuelled by glutamine and branched chain amino acids, generating N-acetylaspartate; (2) the alanine-generating Cahill-cycle; (3) the lactate-releasing Cori-cycle. Moreover, the metabolomics data indicated a shuttling of taurine and hypotaurine between the retinal pigment epithelium and photoreceptors, likely resulting in an additional net transfer of reducing power to photoreceptors. These findings expand our understanding of retinal physiology and pathology and shed new light on neuronal energy homeostasis and the pathogenesis of neurodegenerative diseases.
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Affiliation(s)
- Yiyi Chen
- Institute for Ophthalmic Research, University of TübingenTuebingenGermany
| | - Laimdota Zizmare
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, University of TübingenTuebingenGermany
- Core Facility Metabolomics, Faculty of Medicine, University of TübingenTuebingenGermany
| | - Victor Calbiague
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de ValparaísoValparaísoChile
| | - Lan Wang
- Institute for Ophthalmic Research, University of TübingenTuebingenGermany
| | - Shirley Yu
- Institute for Ophthalmic Research, University of TübingenTuebingenGermany
| | - Fritz W Herberg
- Biochemistry Department, University of KasselTuebingenGermany
| | - Oliver Schmachtenberg
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de ValparaísoValparaísoChile
| | | | - Christoph Trautwein
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, University of TübingenTuebingenGermany
- Core Facility Metabolomics, Faculty of Medicine, University of TübingenTuebingenGermany
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Calbiague-Garcia V, Chen Y, Cádiz B, Tapia F, Paquet-Durand F, Schmachtenberg O. Extracellular lactate as an alternative energy source for retinal bipolar cells. J Biol Chem 2024; 300:106794. [PMID: 38403245 PMCID: PMC10966802 DOI: 10.1016/j.jbc.2024.106794] [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: 12/22/2023] [Revised: 02/11/2024] [Accepted: 02/16/2024] [Indexed: 02/27/2024] Open
Abstract
Retinal bipolar and amacrine cells receive visual information from photoreceptors and participate in the first steps of image processing in the retina. Several studies have suggested the operation of aerobic glycolysis and a lactate shuttle system in the retina due to the high production of this metabolite under aerobic conditions. However, whether bipolar cells form part of this metabolic circuit remains unclear. Here, we show that the monocarboxylate transporter 2 is expressed and functional in inner retinal neurons. Additionally, we used genetically encoded FRET nanosensors to demonstrate the ability of inner retinal neurons to consume extracellular lactate as an alternative to glucose. In rod bipolar cells, lactate consumption allowed cells to maintain the homeostasis of ions and electrical responses. We also found that lactate synthesis and transporter inhibition caused functional alterations and an increased rate of cell death. Overall, our data shed light on a notable but still poorly understood aspect of retinal metabolism.
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Affiliation(s)
- Victor Calbiague-Garcia
- PhD Program in Neuroscience, Universidad de Valparaíso, Valparaíso, Chile; CINV, Instituto de Biología, Universidad de Valparaíso, Valparaíso, Chile.
| | - Yiyi Chen
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Bárbara Cádiz
- CINV, Instituto de Biología, Universidad de Valparaíso, Valparaíso, Chile
| | - Felipe Tapia
- CINV, Instituto de Biología, Universidad de Valparaíso, Valparaíso, Chile
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5
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Shahhossein-Dastjerdi S, Koina ME, Fatseas G, Arfuso F, Chan-Ling T. Autophagy and Exocytosis of Lipofuscin Into the Basolateral Extracellular Space of Human Retinal Pigment Epithelium From Fetal Development to Adolescence. Invest Ophthalmol Vis Sci 2024; 65:32. [PMID: 38648041 PMCID: PMC11044829 DOI: 10.1167/iovs.65.4.32] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 03/06/2024] [Indexed: 04/25/2024] Open
Abstract
Purpose To undertake the first ultrastructural characterization of human retinal pigment epithelial (RPE) differentiation from fetal development to adolescence. Methods Ten fetal eyes and three eyes aged six, nine, and 17 years were examined in the temporal retina adjacent to the optic nerve head by transmission electron microscopy. The area, number, and distribution of RPE organelles were quantified and interpreted within the context of adjacent photoreceptors, Bruch's membrane, and choriocapillaris maturation. Results Between eight to 12 weeks' gestation (WG), pseudostratified columnar epithelia with apical tight junctions differentiate to a simple cuboidal epithelium with random distribution of melanosomes and mitochondria. Between 12 to 26 WG, cells enlarge and show long apical microvilli and apicolateral junctional complexes. Coinciding with eye opening at 26 WG, melanosomes migrate apically whereas mitochondria distribute to perinuclear regions, with the first appearance of phagosomes, complex granules, and basolateral extracellular space (BES) formation. Significantly, autophagy and heterophagy, as evidenced by organelle recycling, and the gold standard of ultrastructural evidence for autophagy of double-membrane autophagosomes and mitophagosomes were evident from 32 WG, followed by basal infoldings of RPE cell membrane at 36 WG. Lipofuscin formation and deposition into the BES evident at six years increased at 17 years. Conclusions We provide compelling ultrastructural evidence that heterophagy and autophagy begins in the third trimester of human fetal development and that deposition of cellular byproducts into the extracellular space of RPE takes place via exocytosis. Transplanted RPE cells must also demonstrate the capacity to subserve autophagic and heterophagic functions for effective disease mitigation.
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Affiliation(s)
- Saeed Shahhossein-Dastjerdi
- Bosch Institute, The University of Sydney, Sydney, Australia
- Now at Cell, Tissue & Organ Bank, Forensic Medicine Research Centre, Tehran, Iran
| | - Mark E. Koina
- Department of Anatomical Pathology, ACT Pathology, The Canberra Hospital, Canberra, Australia
| | - George Fatseas
- Bosch Institute, The University of Sydney, Sydney, Australia
| | - Frank Arfuso
- School of Human Sciences, The University of Western Australia, Crawley, Australia
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Karaosmanoglu B, Imren G, Utine E, Taylan Sekeroglu H, Taskiran EZ. Allele-specific antisense oligonucleotides for the treatment of BEST1-related dominantly inherited retinal diseases: An in vitro model. Exp Eye Res 2024; 241:109833. [PMID: 38369231 DOI: 10.1016/j.exer.2024.109833] [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: 06/08/2023] [Revised: 10/22/2023] [Accepted: 02/15/2024] [Indexed: 02/20/2024]
Abstract
Retinal dystrophies are a common health problem worldwide that are currently incurable due to the inability of retinal cells to regenerate. Inherited retinal diseases (IRDs) are a diverse group of disorders characterized by progressive vision loss caused by photoreceptor cell dysfunction. The eye has always been an attractive organ for the development of novel therapies due to its independent access to the systemic pathway. Moreover, anti-sense oligonucleotides (ASOs), which facilitate manipulation of unwanted mRNAs via degradation or splicing, are undergoing rapid development and have been clinically deployed for the treatment of several diseases. The primary aim of this study was to establish a reliable in vitro model utilizing induced photoreceptor-like cells (PRCs) for assessing the efficacy and safety of ASOs targeting the BEST1 gene. Despite advances in gene therapy, effective treatments for a broad range of IRDs remain limited. An additional aim was to develop an in vitro model for evaluating RNA-based therapeutics, specifically ASOs, for the treatment in IRDs. Firstly, a cell culture model was established by induction of PRCs from dermal fibroblasts via direct programming. The induced PRCs were characterized at both the transcriptomic and protein level. Then, a common single nucleotide polymorphism (SNP) was identified in the BEST1 gene (rs1800007) for targeting with ASOs. ASOs were designed using the GapmeR strategy to target multiple alleles of this SNP, which is potentially suitable for a large proportion of the population. The efficacy and possible off-target effects of these ASOs were also analyzed in the induced PRC model. The findings show that the selected ASOs achieved allele-specific mRNA degradation with virtually no off-target effects on the global transcriptome profile, indicating their potential as safe and effective therapeutic agents. The presented in vitro model is a valuable platform for testing personalized IRD treatments and should inspire further research on RNA-based therapeutics. To the best of our knowledge this study is the first to test RNA-based therapeutics involving the use of ASOs in an induced PRC model. Based on the present findings, it will be possible to establish an ex vivo disease model using dermal fibroblast samples from affected individuals. In other words, the disease model and the ASOs that were successfully designed in this study can serve as a useful platform for the testing of personalized treatments for IRDs.
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Affiliation(s)
- Beren Karaosmanoglu
- Hacettepe University, Faculty of Medicine, Department of Medical Genetics, Turkey
| | - Gozde Imren
- Hacettepe University, Faculty of Medicine, Department of Medical Genetics, Turkey
| | - Eda Utine
- Hacettepe University, Faculty of Medicine, Department of Pediatric Genetics, Turkey
| | | | - Ekim Z Taskiran
- Hacettepe University, Faculty of Medicine, Department of Medical Genetics, Turkey.
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Faust CD, Klettner CA, Toso M, Hageman GS, Eames I, Luthert PJ, Zouache MA. The vascular geometry of the choriocapillaris is associated with spatially heterogeneous molecular exchange with the outer retina. J Physiol 2024; 602:1273-1295. [PMID: 38513000 DOI: 10.1113/jp285050] [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: 07/06/2023] [Accepted: 02/14/2024] [Indexed: 03/23/2024] Open
Abstract
Vision relies on the continuous exchange of material between the photoreceptors, retinal pigment epithelium and choriocapillaris, a dense microvascular bed located underneath the outer retina. The anatomy and physiology of the choriocapillaris and their association with retinal homeostasis have proven difficult to characterize, mainly because of the unusual geometry of this vascular bed. By analysing tissue dissected from 81 human eyes, we show that the thickness of the choriocapillaris does not vary significantly over large portions of the macula or with age. Assessments of spatial variations in the anatomy of the choriocapillaris in three additional human eyes indicate that the location of arteriolar and venular vessels connected to the plane of the choriocapillaris is non-random, and that venular insertions cluster around arteriolar ones. Mathematical models built upon these anatomical analyses reveal that the choriocapillaris contains regions where the transport of passive elements is dominated by diffusion, and that these diffusion-limited regions represent areas of reduced exchange with the outer retina. The width of diffusion-limited regions is determined by arterial flow rate and the relative arrangement of arteriolar and venular insertions. These analyses demonstrate that the apparent complexity of the choriocapillaris conceals a fine balance between several anatomical and functional parameters to effectively support homeostasis of the outer retina. KEY POINTS: The choriocapillaris is the capillary bed supporting the metabolism of photoreceptors and retinal pigment epithelium, two critical components of the visual system located in the outer part of the retina. The choriocapillaris has evolved a planar multipolar vascular geometry that differs markedly from the branched topology of most vasculatures in the human body. Here, we report that this planar multipolar vascular geometry is associated with spatially heterogenous molecular exchange between choriocapillaris and outer retina. Our data and analyses highlight a necessary balance between choriocapillaris anatomical and functional parameters to effectively support homeostasis of the outer retina.
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Affiliation(s)
- Caitlin D Faust
- John A. Moran Eye Center, Department of Ophthalmology & Visual Sciences, University of Utah, Salt Lake City, Utah, USA
| | | | - Marc Toso
- John A. Moran Eye Center, Department of Ophthalmology & Visual Sciences, University of Utah, Salt Lake City, Utah, USA
| | - Gregory S Hageman
- John A. Moran Eye Center, Department of Ophthalmology & Visual Sciences, University of Utah, Salt Lake City, Utah, USA
| | - Ian Eames
- Department of Mechanical Engineering, University College London, London, UK
| | - Philip J Luthert
- Institute of Ophthalmology, University College London, London, UK
| | - Moussa A Zouache
- John A. Moran Eye Center, Department of Ophthalmology & Visual Sciences, University of Utah, Salt Lake City, Utah, USA
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8
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Fei Y, Jo JJ, Chen S, Ledesma-Gil G, Otero-Marquez O, Mordechaev E, Le B, Tong Y, Tai K, Lema G, Rosen RB, Agarwal VV, Smith RT. Quantifying cardiac dysfunction and valvular heart disease associated with subretinal drusenoid deposits in age-related macular degeneration. Eur J Ophthalmol 2024:11206721241244413. [PMID: 38545630 DOI: 10.1177/11206721241244413] [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: 04/17/2024]
Abstract
BACKGROUND/AIMS Demonstrate through objective multidisciplinary imaging that subretinal drusenoid deposits (SDDs) in age-related macular degeneration (AMD) are linked to both coexistent valvular heart disease (VHD) and reduced systemic perfusion via cardiac index (CI). METHODS Post-hoc analysis of cross-sectional study. 200 intermediate AMD (iAMD) subjects were assigned by masked readers to two groups: SDD (with or without drusen) and drusen (only) based on multimodal ophthalmic imaging. 65 transthoracic echocardiograms (TTEs) reports were available for cardiologist evaluation of VHD severity of the four cardiac valves and the presences of precursor lesions of aortic sclerosis (ASc) and mitral annular calcification (MAC). Necessary parameters to calculate CI were also obtained. Univariate testing was performed using Fisher's Exact test and t-test. RESULTS 82.6% (19/23) of the iAMD subjects with at least one moderate/severe VHD had concurrent SDDs (p = 0.0040). All cases of aortic regurgitation (6/6, p = 0.0370) and mitral regurgitation (13/13, p = 0.0004) were found with coexisting SDDs. Stenotic VHD was not significantly associated with SDDs, however 70.7% of subjects with ASc (29/41, p = 0.0108) and 76.0% of subjects with MAC (19/25, 0.0377) had coexisting SDDs. CI was available in 48 subjects and was significantly below normal levels in the SDD cohort (mean CI SDD 1.95 ± 0.60 L/min/m2, non-SDD 2.71 ± 0.73 L/min/m2, p = 0.0004). CONCLUSIONS Several specific VHDs have been found associated with the SDD form of AMD. Decreased systemic perfusion as measured by CI was also associated with SDDs, which supports a perfusion hypothesis of SDD pathogenesis. Further research is warranted to understand the relationship between cardiovascular disease and SDDs.
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Affiliation(s)
- Yang Fei
- Ophthalmology, New York Eye and Ear Infirmary of Mount Sinai, New York, NY, USA
| | - Jason J Jo
- Ophthalmology, New York Eye and Ear Infirmary of Mount Sinai, New York, NY, USA
| | - Sophie Chen
- Ophthalmology, New York Eye and Ear Infirmary of Mount Sinai, New York, NY, USA
| | - Gerardo Ledesma-Gil
- Retina Department, Institute of Ophthalmology Fundación Conde de Valenciana, Mexico, Mexico
| | | | - Emanuel Mordechaev
- Ophthalmology, New York Eye and Ear Infirmary of Mount Sinai, New York, NY, USA
| | - Brandon Le
- Ophthalmology, New York Eye and Ear Infirmary of Mount Sinai, New York, NY, USA
| | - Yuehong Tong
- New York Eye and Ear Infirmary of Mount Sinai, New York, NY, USA
| | - Katy Tai
- Ophthalmology, New York Eye and Ear Infirmary of Mount Sinai, New York, NY, USA
| | - Gareth Lema
- Vitreoretinal Surgery, New York Eye and Ear Infirmary of Mount Sinai, New York, NY, USA
| | - Richard B Rosen
- Ophthalmology, New York Eye and Ear Infirmary of Mount Sinai, New York, NY, USA
| | | | - Roland Theodore Smith
- New York Eye and Ear Infirmary of Mount Sinai, New York, NY, USA
- Icahn School of Medicine at Mount Sinai, New York, NY, USA
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Du X, Butler AG, Chen HY. Cell-cell interaction in the pathogenesis of inherited retinal diseases. Front Cell Dev Biol 2024; 12:1332944. [PMID: 38500685 PMCID: PMC10944940 DOI: 10.3389/fcell.2024.1332944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 02/06/2024] [Indexed: 03/20/2024] Open
Abstract
The retina is part of the central nervous system specialized for vision. Inherited retinal diseases (IRD) are a group of clinically and genetically heterogenous disorders that lead to progressive vision impairment or blindness. Although each disorder is rare, IRD accumulatively cause blindness in up to 5.5 million individuals worldwide. Currently, the pathophysiological mechanisms of IRD are not fully understood and there are limited treatment options available. Most IRD are caused by degeneration of light-sensitive photoreceptors. Genetic mutations that abrogate the structure and/or function of photoreceptors lead to visual impairment followed by blindness caused by loss of photoreceptors. In healthy retina, photoreceptors structurally and functionally interact with retinal pigment epithelium (RPE) and Müller glia (MG) to maintain retinal homeostasis. Multiple IRD with photoreceptor degeneration as a major phenotype are caused by mutations of RPE- and/or MG-associated genes. Recent studies also reveal compromised MG and RPE caused by mutations in ubiquitously expressed ciliary genes. Therefore, photoreceptor degeneration could be a direct consequence of gene mutations and/or could be secondary to the dysfunction of their interaction partners in the retina. This review summarizes the mechanisms of photoreceptor-RPE/MG interaction in supporting retinal functions and discusses how the disruption of these processes could lead to photoreceptor degeneration, with an aim to provide a unique perspective of IRD pathogenesis and treatment paradigm. We will first describe the biology of retina and IRD and then discuss the interaction between photoreceptors and MG/RPE as well as their implications in disease pathogenesis. Finally, we will summarize the recent advances in IRD therapeutics targeting MG and/or RPE.
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Affiliation(s)
| | | | - Holly Y. Chen
- Department of Cell, Developmental and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
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10
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Liebold F, Adler W, Jansen S, Klussmann JP, Meyer M, Nehrlich L, Schmitz J, Vingerhoets A, Heindl LM, Hinkelbein J. Evaluation of colour vision impairment during acute hypobaric hypoxia in aviation medicine: a randomized controlled trial. J Physiol Sci 2024; 74:6. [PMID: 38311742 PMCID: PMC10840265 DOI: 10.1186/s12576-024-00898-4] [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: 09/16/2023] [Accepted: 01/18/2024] [Indexed: 02/06/2024]
Abstract
The digitization of aircraft cockpits places high demands on the colour vision of pilots. The present study investigates colour vision changes upon acute exposure to hypobaric hypoxia. The digital Waggoner Computerized Color Vision Test and the Waggoner D-15 were performed by 54 healthy volunteers in a decompression chamber. Respective altitude levels were sea level, 10,000 or 15,000 ft for exposure periods of 15 and 60 min, respectively. As for 60 min of exposure a significant decrease in colour perception was found between subjects at 15,000 ft as compared to the control group as well as between subjects at 15,000 ft as compared to subjects at 10,000 ft. No significant difference was found in the comparison within the 15,000 ft groups across time points pre-, peri-, and post-exposure. Thus, pilots appear to experience only minor colour vision impairment up to an exposure altitude of 15,000 ft over 60 min of exposure.
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Affiliation(s)
- F Liebold
- Department of Anaesthesiology und Intensive Care Medicine, University Hospital and Faculty of Medicine Cologne, Cologne, Germany.
- Department of Anaesthesiology und Intensive Care Medicine, University Hospital and Faculty of Medicine Leipzig, Liebigstraße 20, 04103, Leipzig, Germany.
| | - W Adler
- Institute for Medical Informatics, Biometry and Epidemiology (IMBE), Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - S Jansen
- Department of Otorhinolaryngology, University Hospital and Faculty of Medicine Cologne, Cologne, Germany
| | - J P Klussmann
- Department of Otorhinolaryngology, University Hospital and Faculty of Medicine Cologne, Cologne, Germany
| | - M Meyer
- Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Essen, University of Duisburg-Essen, Duisburg, Germany
| | - L Nehrlich
- Department of Anaesthesiology und Intensive Care Medicine, University Hospital and Faculty of Medicine Cologne, Cologne, Germany
| | - J Schmitz
- Department of Anaesthesiology und Intensive Care Medicine, University Hospital and Faculty of Medicine Cologne, Cologne, Germany
- Department of Sleep and Human Factor, German Aerospace Centre, Linder Höhe, 51147, Cologne, Germany
| | - A Vingerhoets
- Department of Medical and Clinical Psychology, Tilburg University, Tilburg, Netherlands
| | - L M Heindl
- Department of Ophthalmology, University Hospital and Faculty of Medicine Cologne, Cologne, Germany
| | - J Hinkelbein
- Johannes Wesling Klinikum Minden, University Hospital, Ruhr University Bochum, Bochum, Germany
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11
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Neriyanuri S, Bedggood P, Symons RCA, Metha AB. Validation of an automated method for studying retinal capillary blood flow. BIOMEDICAL OPTICS EXPRESS 2024; 15:802-817. [PMID: 38404315 PMCID: PMC10890846 DOI: 10.1364/boe.504074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 12/13/2023] [Accepted: 12/28/2023] [Indexed: 02/27/2024]
Abstract
Two major approaches for tracking cellular motion across a range of biological tissues are the manual labelling of cells, and automated analysis of spatiotemporal information represented in a kymograph. Here we compare these two approaches for the measurement of retinal capillary flow, a particularly noisy application due to the low intrinsic contrast of single red blood cells (erythrocytes). Image data were obtained using a flood-illuminated adaptive optics ophthalmoscope at 750 nm, allowing the acquisition of flow information over several cardiac cycles which provided key information in evaluating tracking accuracy. Our results show that in addition to being much faster, the automated method is more accurate in the face of rapid flow and reduced image contrast. This study represents the first validation of commonly used kymograph approaches to capillary flow analysis.
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Affiliation(s)
- Srividya Neriyanuri
- Department of Optometry and Vision Sciences, The University of Melbourne, VIC 3053, Australia
| | - Phillip Bedggood
- Department of Optometry and Vision Sciences, The University of Melbourne, VIC 3053, Australia
| | - R. C. Andrew Symons
- Department of Optometry and Vision Sciences, The University of Melbourne, VIC 3053, Australia
- Department of Surgery, The University of Melbourne, VIC 3053, Australia
- Centre for Eye Research (CERA), VIC 3002, Australia
- Department of Surgery, Alfred Hospital, Monash University, VIC 3004, Australia
| | - Andrew B. Metha
- Department of Optometry and Vision Sciences, The University of Melbourne, VIC 3053, Australia
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12
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Yang Z, Yan L, Zhang W, Qi J, An W, Yao K. Dyschromatopsia: a comprehensive analysis of mechanisms and cutting-edge treatments for color vision deficiency. Front Neurosci 2024; 18:1265630. [PMID: 38298913 PMCID: PMC10828017 DOI: 10.3389/fnins.2024.1265630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Accepted: 01/02/2024] [Indexed: 02/02/2024] Open
Abstract
Color blindness is a retinal disease that mainly manifests as a color vision disorder, characterized by achromatopsia, red-green color blindness, and blue-yellow color blindness. With the development of technology and progress in theory, extensive research has been conducted on the genetic basis of color blindness, and various approaches have been explored for its treatment. This article aims to provide a comprehensive review of recent advances in understanding the pathological mechanism, clinical symptoms, and treatment options for color blindness. Additionally, we discuss the various treatment approaches that have been developed to address color blindness, including gene therapy, pharmacological interventions, and visual aids. Furthermore, we highlight the promising results from clinical trials of these treatments, as well as the ongoing challenges that must be addressed to achieve effective and long-lasting therapeutic outcomes. Overall, this review provides valuable insights into the current state of research on color blindness, with the intention of informing further investigation and development of effective treatments for this disease.
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Affiliation(s)
- Zihao Yang
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Lin Yan
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Wenliang Zhang
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Jia Qi
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Wenjing An
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Kai Yao
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
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13
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Wang J, Sadlak N, Fiorello MG, Desai M, Yi J. Macular Oxygen Saturation in Glaucoma Using Retinal Oximetry of Visible Light Optical Coherence Tomography. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.12.20.23300300. [PMID: 38196641 PMCID: PMC10775404 DOI: 10.1101/2023.12.20.23300300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
Purpose Oxygen saturation (sO2) plays a critical role in retinal pathophysiology, especially at the macula, which undergoes significant energy consumption. While macular damage has been suggested to be involved in early-stage glaucoma, there has been no report to date on non-invasive macular sO2 in glaucoma. Therefore, we conducted this study to compare macular sO2 associated with other clinical measurements between normal and glaucoma subjects and evaluate whether there are significant differences. Method This is a cross-sectional study. We used visible light optical coherence tomography (VIS-OCT) for retinal oximetry in perifoveal vessels. The subjects from groups of normal, suspect/pre-perimetric glaucoma (GS/PPG) and perimetric glaucoma (PG) were scanned using VIS-OCT in the macular region with a sampling density of 512×256 in an area of 5×5 mm2. 48 eyes (16 normal, 17 GS/PPG and 15 PG) were included for the analysis. For each eye, we measured the sO2 of arterioles (AsO2), venules (VsO2), and calculated the difference between arterioles and venules (A-V sO2=AsO2-VsO2), oxygen extraction (OE=(AsO2-VsO2)/AsO2 ×100%). Additionally, we included Zeiss Cirrus OCT scans and 24-2 visual field test (VFT) for clinical benchmark. One-way ANOVA was used to compare the differences among the three groups. Spearman correlation tests were used for correlation sO2 markers to standard metrics including the thickness of ganglion cell layer and inner plexiform layer (GCL+IPL), circumpapillary retinal nerve fiber layer (cpRNFL) and mean deviation (MD) in VFT. Result Significant differences were found among three groups for all VIS-OCT, Zeiss OCT, and VFT variables. Macular AsO2, A-V sO2, OE decreased, and VsO2 increased along with severity. Macular AsO2 and A-V sO2 were statistically correlated with GCL+IPL and cpRNFL in all eyes, as well as only PG eyes. Within PG eyes, the correlation between AsO2 and GCL+IPL is dominant in more damaged lower hemifield. Conclusion The GS/PPG and PG subjects had significantly higher macular VsO2, lower A-V sO2 and OE indicating less oxygen consumption. The sO2 measured by retinal oximetry of VIS-OCT can be a potential metric for the early diagnosis of glaucoma.
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Affiliation(s)
- Jingyu Wang
- Department of Ophthalmology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Natalie Sadlak
- Department of Ophthalmology, Boston Medical Center, Boston, MA, USA
| | | | - Manishi Desai
- Department of Ophthalmology, Boston Medical Center, Boston, MA, USA
| | - Ji Yi
- Department of Ophthalmology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
- Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, MA, USA
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
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14
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Menger KE, Logan A, Luhmann UF, Smith AJ, Wright AF, Ali RR, Murphy MP. In vivo measurement of mitochondrial ROS production in mouse models of photoreceptor degeneration. REDOX BIOCHEMISTRY AND CHEMISTRY 2023; 5-6:None. [PMID: 38046619 PMCID: PMC10686909 DOI: 10.1016/j.rbc.2023.100007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 07/18/2023] [Accepted: 07/24/2023] [Indexed: 12/05/2023]
Abstract
Retinitis pigmentosa (RP) is a disease characterised by photoreceptor cell death. It can be initiated by mutations in a number of different genes, primarily affecting rods, which will die first, resulting in loss of night vision. The secondary death of cones then leads to loss of visual acuity and blindness. We set out to investigate whether increased mitochondrial reactive oxygen species (ROS) formation, plays a role in this sequential photoreceptor degeneration. To do this we measured mitochondrial H2O2 production within mouse eyes in vivo using the mass spectrometric probe MitoB. We found higher levels of mitochondrial ROS that preceded photoreceptor loss in four mouse models of RP: Pde6brd1/rd1; Prhp2rds/rds; RPGR-/-; Cln6nclf. In contrast, there was no increase in mitochondrial ROS in loss of function models of vision loss (GNAT-/-, OGC), or where vision loss was not due to photoreceptor death (Cln3). Upregulation of Nrf2 transcriptional activity with dimethylfumarate (DMF) lowered mitochondrial ROS in RPGR-/- mice. These findings have important implications for the mechanism and treatment of RP.
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Affiliation(s)
- Katja E. Menger
- UCL Institute of Ophthalmology, Bath St, London, EC1V 9EL, UK
| | - Angela Logan
- MRC-Mitochondrial Biology Unit, The Keith Peters Building, University of Cambridge, Cambridge, CB2 0XY, UK
| | | | | | - Alan F. Wright
- MRC Human Genetics Unit, Western General Hospital, University of Edinburgh, Edinburgh, EH4 2XU, UK
| | - Robin R. Ali
- UCL Institute of Ophthalmology, Bath St, London, EC1V 9EL, UK
| | - Michael P. Murphy
- MRC-Mitochondrial Biology Unit, The Keith Peters Building, University of Cambridge, Cambridge, CB2 0XY, UK
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15
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Sezai T, Murphy MJ, Riddell N, Nguyen V, Crewther SG. Visual Processing During the Interictal Period Between Migraines: A Meta-Analysis. Neuropsychol Rev 2023; 33:765-782. [PMID: 36115887 PMCID: PMC10770263 DOI: 10.1007/s11065-022-09562-3] [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: 10/20/2021] [Accepted: 07/20/2022] [Indexed: 10/14/2022]
Abstract
Migraine is a poorly understood neurological disorder and a leading cause of disability in young adults, particularly women. Migraines are characterized by recurring episodes of severe pulsating unilateral headache and usually visual symptoms. Currently there is some disagreement in the electrophysiological literature regarding the universality of all migraineurs exhibiting physiological visual impairments also during interictal periods (i.e., the symptom free period between migraines). Thus, this meta-analysis investigated the evidence for altered visual function as measured electrophysiologically via pattern-reversal visual evoked potential (VEP) amplitudes and habituation in adult migraineurs with or without visual aura and controls in the interictal period. Twenty-three studies were selected for random effects meta-analysis which demonstrated slightly diminished VEP amplitudes in the early fast conducting P100 component but not in N135, and substantially reduced habituation in the P100 and the N135 in migraineurs with and without visual aura symptoms compared to controls. No statistical differences were found between migraineurs with and without aura, possibly due to inadequate studies. Overall, insufficient published data and substantial heterogeneity between studies was observed for all latency components of pattern-reversal VEP, highlighting the need for further electrophysiological experimentation and more targeted temporal analysis of visual function, in episodic migraineurs.
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Affiliation(s)
- Timucin Sezai
- Department of Psychology and Counselling, School of Psychology and Public Health, La Trobe University, Melbourne, VIC, 3086, Australia
| | - Melanie J Murphy
- Department of Psychology and Counselling, School of Psychology and Public Health, La Trobe University, Melbourne, VIC, 3086, Australia
| | - Nina Riddell
- Department of Psychology and Counselling, School of Psychology and Public Health, La Trobe University, Melbourne, VIC, 3086, Australia
| | - Vinh Nguyen
- Department of Psychology and Counselling, School of Psychology and Public Health, La Trobe University, Melbourne, VIC, 3086, Australia
| | - Sheila G Crewther
- Department of Psychology and Counselling, School of Psychology and Public Health, La Trobe University, Melbourne, VIC, 3086, Australia.
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16
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Böhm EW, Buonfiglio F, Voigt AM, Bachmann P, Safi T, Pfeiffer N, Gericke A. Oxidative stress in the eye and its role in the pathophysiology of ocular diseases. Redox Biol 2023; 68:102967. [PMID: 38006824 DOI: 10.1016/j.redox.2023.102967] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 11/10/2023] [Accepted: 11/14/2023] [Indexed: 11/27/2023] Open
Abstract
Oxidative stress occurs through an imbalance between the generation of reactive oxygen species (ROS) and the antioxidant defense mechanisms of cells. The eye is particularly exposed to oxidative stress because of its permanent exposure to light and due to several structures having high metabolic activities. The anterior part of the eye is highly exposed to ultraviolet (UV) radiation and possesses a complex antioxidant defense system to protect the retina from UV radiation. The posterior part of the eye exhibits high metabolic rates and oxygen consumption leading subsequently to a high production rate of ROS. Furthermore, inflammation, aging, genetic factors, and environmental pollution, are all elements promoting ROS generation and impairing antioxidant defense mechanisms and thereby representing risk factors leading to oxidative stress. An abnormal redox status was shown to be involved in the pathophysiology of various ocular diseases in the anterior and posterior segment of the eye. In this review, we aim to summarize the mechanisms of oxidative stress in ocular diseases to provide an updated understanding on the pathogenesis of common diseases affecting the ocular surface, the lens, the retina, and the optic nerve. Moreover, we discuss potential therapeutic approaches aimed at reducing oxidative stress in this context.
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Affiliation(s)
- Elsa Wilma Böhm
- Department of Ophthalmology, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstrasse 1, 55131, Mainz, Germany.
| | - Francesco Buonfiglio
- Department of Ophthalmology, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstrasse 1, 55131, Mainz, Germany
| | - Anna Maria Voigt
- Department of Ophthalmology, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstrasse 1, 55131, Mainz, Germany
| | - Philipp Bachmann
- Department of Ophthalmology, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstrasse 1, 55131, Mainz, Germany
| | - Tarek Safi
- Department of Ophthalmology, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstrasse 1, 55131, Mainz, Germany
| | - Norbert Pfeiffer
- Department of Ophthalmology, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstrasse 1, 55131, Mainz, Germany
| | - Adrian Gericke
- Department of Ophthalmology, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstrasse 1, 55131, Mainz, Germany.
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17
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Gao S, Gao S, Wang Y, Li N, Yang Z, Yao H, Chen Y, Cheng Y, Zhong Y, Shen X. Inhibition of Ferroptosis Ameliorates Photoreceptor Degeneration in Experimental Diabetic Mice. Int J Mol Sci 2023; 24:16946. [PMID: 38069270 PMCID: PMC10707664 DOI: 10.3390/ijms242316946] [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: 10/07/2023] [Revised: 11/19/2023] [Accepted: 11/27/2023] [Indexed: 12/18/2023] Open
Abstract
Diabetic retinopathy (DR) is a leading cause of vision impairment in the working-age population worldwide. Various modes of photoreceptor cell death contribute to the development of DR, including apoptosis and autophagy. However, whether ferroptosis is involved in the pathogenesis of photoreceptor degeneration in DR is still unclear. High-glucose (HG)-stimulated 661W cells and diabetic mice models were used for in vitro and in vivo experiments, respectively. The levels of intracellular iron, glutathione (GSH), reactive oxygen species (ROS), lipid peroxidation (MDA), and ferroptosis-related proteins (GPX4, SLC7A11, ACSL4, FTH1, and NCOA4) were quantified to indicate ferroptosis. The effect of ferroptosis inhibition was also assessed. Our data showed the levels of iron, ROS, and MDA were enhanced and GSH concentration was reduced in HG-induced 661W cells and diabetic retinas. The expression of GPX4 and SLC7A11 was downregulated, while the expression of ACSL4, FTH1, and NCOA4 was upregulated in the 661W cells cultured under HG conditions and in the photoreceptor cells in diabetic mice. Furthermore, the administration of the ferroptosis inhibitor ferrostatin-1 (Fer-1) obviously alleviated ferroptosis-related changes in HG-cultured 661W cells and in retinal photoreceptor cells in diabetic mice. Taken together, our findings suggest that ferroptosis is involved in photoreceptor degeneration in the development of the early stages of DR.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Xi Shen
- Department of Ophthalmology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No. 197, Ruijin 2nd Road, Shanghai 200025, China; (S.G.)
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18
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Knight LJ, Martis RM, Donaldson PJ, Acosta ML, Lim JC. Changes in glutamate and glutamine distributions in the retinas of cystine/glutamate antiporter knockout mice. Mol Vis 2023; 29:274-288. [PMID: 38222448 PMCID: PMC10784226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Accepted: 11/02/2023] [Indexed: 01/16/2024] Open
Abstract
Purpose The cystine/glutamate antiporter is involved in the export of intracellular glutamate in exchange for extracellular cystine. Glutamate is the main neurotransmitter in the retina and plays a key metabolic role as a major anaplerotic substrate in the tricarboxylic acid cycle to generate adenosine triphosphate (ATP). In addition, glutamate is also involved in the outer plexiform glutamate-glutamine cycle, which links photoreceptors and supporting Müller cells and assists in maintaining photoreceptor neurotransmitter supply. In this study, we investigated the role of xCT, the light chain subunit responsible for antiporter function, in glutamate pathways in the mouse retina using an xCT knockout mouse. As xCT is a glutamate exporter, we hypothesized that loss of xCT function may influence the presynaptic metabolism of photoreceptors and postsynaptic levels of glutamate. Methods Retinas of C57BL/6J wild-type (WT) and xCT knockout (KO) mice of either sex were analyzed from 6 weeks to 12 months of age. Biochemical assays were used to determine the effect of loss of xCT on glycolysis and energy metabolism by measuring lactate dehydrogenase activity and ATP levels. Next, biochemical assays were used to measure whole-tissue glutamate and glutamine levels, while silver-intensified immunogold labeling was performed on 6-week and 9-month-old retinas to visualize and quantify the distribution of glutamate, glutamine, and related neurochemical substrates gamma-aminobutyric acid (GABA) and glycine in the different layers of the retina. Results Biochemical analysis revealed that loss of xCT function did not alter the lactate dehydrogenase activity, ATP levels, or glutamate and glutamine contents in whole retinas in any age group. However, at 6 weeks of age, the xCT KO retinas revealed altered glutamate distribution compared with the age-matched WT retinas, with accumulation of glutamate in the photoreceptors and outer plexiform layer. In addition, at 6 weeks and 9 months of age, the xCT KO retinas also showed altered glutamine distribution compared with the WT retinas, with glutamine labeling significantly decreased in Müller cell bodies. No significant difference in GABA or glycine distribution were found between the WT and xCT KO retinas at 6 weeks or 9 months of age. Conclusion Loss of xCT function results in glutamate metabolic disruption through the accumulation of glutamate in photoreceptors and a reduced uptake of glutamate by Müller cells, which in turn decreases glutamine production. These findings support the idea that xCT plays a role in the presynaptic metabolism of photoreceptors and postsynaptic levels of glutamate and derived neurotransmitters in the retina.
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Affiliation(s)
- Luis J Knight
- Department of Physiology, School of Medical Sciences, University of Auckland
- New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Renita M Martis
- Department of Physiology, School of Medical Sciences, University of Auckland
- School of Optometry and Vision Science, University of Auckland
- New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Paul J Donaldson
- Department of Physiology, School of Medical Sciences, University of Auckland
- New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Monica L Acosta
- School of Optometry and Vision Science, University of Auckland
- New Zealand National Eye Centre, University of Auckland, New Zealand
- Centre for Brain Research, University of Auckland, New Zealand
| | - Julie C Lim
- Department of Physiology, School of Medical Sciences, University of Auckland
- New Zealand National Eye Centre, University of Auckland, New Zealand
- Centre for Brain Research, University of Auckland, New Zealand
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19
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Gierke K, Lux UT, Regus-Leidig H, Brandstätter JH. The first synapse in vision in the aging mouse retina. Front Cell Neurosci 2023; 17:1291054. [PMID: 38026697 PMCID: PMC10654782 DOI: 10.3389/fncel.2023.1291054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 10/20/2023] [Indexed: 12/01/2023] Open
Abstract
Vision is our primary sense, and maintaining it throughout our lifespan is crucial for our well-being. However, the retina, which initiates vision, suffers from an age-related, irreversible functional decline. What causes this functional decline, and how it might be treated, is still unclear. Synapses are the functional hub for signal transmission between neurons, and studies have shown that aging is widely associated with synaptic dysfunction. In this study, we examined the first synapse of the visual system - the rod and cone photoreceptor ribbon synapse - in the mouse retina using light and electron microscopy at 2-3 months, ~1 year, and >2 years of age. We asked, whether age-related changes in key synaptic components might be a driver of synaptic dysfunction and ultimately age-related functional decline during normal aging. We found sprouting of horizontal and bipolar cells, formation of ectopic photoreceptor ribbon synapses, and a decrease in the number of rod photoreceptors and photoreceptor ribbon synapses in the aged retina. However, the majority of the photoreceptors did not show obvious changes in the structural components and protein composition of their ribbon synapses. Noteworthy is the increase in mitochondrial size in rod photoreceptor terminals in the aged retina.
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Affiliation(s)
| | | | | | - Johann Helmut Brandstätter
- Animal Physiology/Neurobiology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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20
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Afiat BC, Zhao D, Wong VHY, Perera ND, Turner BJ, Nguyen CTO, Bui BV. Age-related deficits in retinal autophagy following intraocular pressure elevation in autophagy reporter mouse model. Neurobiol Aging 2023; 131:74-87. [PMID: 37586253 DOI: 10.1016/j.neurobiolaging.2023.07.009] [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: 01/18/2023] [Revised: 07/12/2023] [Accepted: 07/13/2023] [Indexed: 08/18/2023]
Abstract
This study quantified age-related changes to retinal autophagy using the CAG-RFP-EGFP-LC3 autophagy reporter mice and considered how aging impacts autophagic responses to acute intraocular pressure (IOP) stress. IOP was elevated to 50 mm Hg for 30 minutes in 3-month-old and 12-month-old CAG-RFP-EGFP-LC3 (n = 7 per age group) and Thy1-YFPh transgenic mice (n = 3 per age group). Compared with younger eyes, older eyes showed diminished basal autophagy in the outer retina, while the inner retina was unaffected. Autophagic flux (red:yellow puncta ratio) was elevated in the inner plexiform layer. Three days following IOP elevation, older eyes showed poorer functional recovery, most notably in ganglion cell responses compared to younger eyes (12 months old: -33.4 ± 5.3% vs. 3 months mice: -13.4 ± 4.5%). This paralleled a reduced capacity to upregulate autophagic puncta volume in the inner retina in older eyes, a response that was seen in younger eyes. Age-related decline in basal and stress-induced autophagy in the retina is associated with greater retinal ganglion cells' susceptibility to IOP elevation.
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Affiliation(s)
- Brianna C Afiat
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Da Zhao
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Vickie H Y Wong
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Nirma D Perera
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Bradley J Turner
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Christine T O Nguyen
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Bang V Bui
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia.
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21
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Herrera I, Fernandes JAL, Shir-Mohammadi K, Levesque J, Mattar P. Lamin A upregulation reorganizes the genome during rod photoreceptor degeneration. Cell Death Dis 2023; 14:701. [PMID: 37880237 PMCID: PMC10600220 DOI: 10.1038/s41419-023-06224-x] [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: 01/26/2023] [Revised: 10/10/2023] [Accepted: 10/16/2023] [Indexed: 10/27/2023]
Abstract
Neurodegenerative diseases are accompanied by dynamic changes in gene expression, including the upregulation of hallmark stress-responsive genes. While the transcriptional pathways that impart adaptive and maladaptive gene expression signatures have been the focus of intense study, the role of higher order nuclear organization in this process is less clear. Here, we examine the role of the nuclear lamina in genome organization during the degeneration of rod photoreceptors. Two proteins had previously been shown to be necessary and sufficient to tether heterochromatin at the nuclear envelope. The lamin B receptor (Lbr) is expressed during development, but downregulates upon rod differentiation. A second tether is the intermediate filament lamin A (LA), which is not normally expressed in murine rods. Here, we show that in the rd1 model of retinitis pigmentosa, LA ectopically upregulates in rod photoreceptors at the onset of degeneration. LA upregulation correlated with increased heterochromatin tethering at the nuclear periphery in rd1 rods, suggesting that LA reorganizes the nucleus. To determine how heterochromatin tethering affects the genome, we used in vivo electroporation to misexpress LA or Lbr in mature rods in the absence of degeneration, resulting in the restoration of conventional nuclear architecture. Using scRNA-seq, we show that reorganizing the nucleus via LA/Lbr misexpression has relatively minor effects on rod gene expression. Next, using ATAC-seq, we show that LA and Lbr both lead to marked increases in genome accessibility. Novel ATAC-seq peaks tended to be associated with stress-responsive genes. Together, our data reveal that heterochromatin tethers have a global effect on genome accessibility, and suggest that heterochromatin tethering primes the photoreceptor genome to respond to stress.
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Affiliation(s)
- Ivana Herrera
- Ottawa Hospital Research Institute (OHRI), Ottawa, ON, K1H 8L6, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
| | - José Alex Lourenço Fernandes
- Ottawa Hospital Research Institute (OHRI), Ottawa, ON, K1H 8L6, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
| | - Khatereh Shir-Mohammadi
- Ottawa Hospital Research Institute (OHRI), Ottawa, ON, K1H 8L6, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
| | - Jasmine Levesque
- Ottawa Hospital Research Institute (OHRI), Ottawa, ON, K1H 8L6, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
| | - Pierre Mattar
- Ottawa Hospital Research Institute (OHRI), Ottawa, ON, K1H 8L6, Canada.
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada.
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Sakti DH, Cornish EE, Nash BM, Jamieson RV, Grigg JR. IMPDH1-associated autosomal dominant retinitis pigmentosa: natural history of novel variant Lys314Gln and a comprehensive literature search. Ophthalmic Genet 2023; 44:437-455. [PMID: 37259572 DOI: 10.1080/13816810.2023.2215310] [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: 01/27/2023] [Revised: 05/11/2023] [Accepted: 05/14/2023] [Indexed: 06/02/2023]
Abstract
BACKGROUND Inosine monophosphate dehydrogenase (IMPDH) is a key regulatory enzyme in the de novo synthesis of the purine base guanine. Mutations in the inosine monophosphate dehydrogenase 1 gene (IMPDH1) are causative for RP10 autosomal dominant retinitis pigmentosa (adRP). This study reports a novel variant in a family with IMPDH1-associated retinopathy. We also performed a comprehensive review of all reported IMPDH1 disease causing variants with their associated phenotype. MATERIALS AND METHODS Multimodal imaging and functional studies documented the phenotype including best-corrected visual acuity (BCVA), fundus photograph, fundus autofluorescence (FAF), full field electroretinogram (ffERG), optical coherence tomography (OCT) and visual field (VF) data were collected. A literature search was performed in the PubMed and LOVD repositories. RESULTS We report 3 cases from a 2-generation family with a novel heterozygous likely pathogenic variant p. (Lys314Gln) (exon 10). The ophthalmic phenotype showed diffuse outer retinal atrophy with mild pigmentary changes with sparse pigmentary changes. FAF showed early macular involvement with macular hyperautofluorescence (hyperAF) surrounded by hypoAF. Foveal ellipsoid zone island can be found in the youngest patient but not in the older ones. The literature review identified a further 56 heterozygous, 1 compound heterozygous, and 2 homozygous variant. The heterozygous group included 43 missense, 3 in-frame, 1 nonsense, 2 frameshift, 1 synonymous, and 6 intronic variants. Exon 10 was noted as a hotspot harboring 18 variants. CONCLUSIONS We report a novel IMPDH1 variant. IMPDH1-associated retinopathy presents most frequently in the first decade of life with early macular involvement.
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Affiliation(s)
- Dhimas H Sakti
- Save Sight Institute, University of Sydney, Sydney, New South Wales, Australia
- Department of Ophthalmology, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Elisa E Cornish
- Save Sight Institute, University of Sydney, Sydney, New South Wales, Australia
- Eye Genetics Research Unit, Children's Medical Research Institute, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Benjamin M Nash
- Eye Genetics Research Unit, Children's Medical Research Institute, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
- Sydney Genome Diagnostics, Western Sydney Genetics Program, Sydney Children's Hospitals Network, Sydney, New South Wales, Australia
| | - Robyn V Jamieson
- Eye Genetics Research Unit, Children's Medical Research Institute, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - John R Grigg
- Save Sight Institute, University of Sydney, Sydney, New South Wales, Australia
- Eye Genetics Research Unit, Children's Medical Research Institute, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
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23
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Zhu Q, Cao X, Zhang Y, Zhou Y, Zhang J, Zhang X, Zhu Y, Xue L. Repeated Low-Level Red-Light Therapy for Controlling Onset and Progression of Myopia-a Review. Int J Med Sci 2023; 20:1363-1376. [PMID: 37786442 PMCID: PMC10542022 DOI: 10.7150/ijms.85746] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Accepted: 07/10/2023] [Indexed: 10/04/2023] Open
Abstract
Repeated low-level red-light (RLRL), characterized by increased energy supply and cellular metabolism, thus enhancing metabolic repair processes, has gained persistent worldwide attention in recent years as a new novel scientific approach for therapeutic application in myopia. This therapeutic revolution led by RLRL therapy is due to significant advances in bioenergetics and photobiology, for instance, enormous progresses in photobiomodulation regulated by cytochrome c oxidase, the primary photoreceptor of the light in the red to near infrared regions of the electromagnetic spectrum, as the primary mechanism of action in RLRL therapy. This oxidase is also a key mitochondrial enzyme for cellular bioenergetics, especially for the nerve cells in the retina and brain. In addition, dopamine (DA)-enhanced release of nitric oxide may also be involved in controlling myopia by activation of nitric oxide synthase, enhancing cGMP signaling. Recent evidence has also suggested that RLRL may inhibit myopia progression by inhibiting spherical equivalent refraction (SER) progression and axial elongation without adverse effects. In this review, we provide scientific evidence for RLRL therapy as a unique paradigm to control myopia and support the theory that targeting neuronal energy metabolism may constitute a major target for the neurotherapeutics of myopia, with emphasis on its molecular, cellular, and nervous tissue levels, and the potential benefits of RLRL therapy for myopia.
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Affiliation(s)
- Qin Zhu
- Department of Pediatric Ophthalmology, Affiliated Hospital of Yunnan University, Kunming 650021, China
| | - Xuejun Cao
- Department of Ophthalmology, the First Affiliated Hospital of Kunming Medical University, Kunming 650031, China
| | - Yuan Zhang
- BioTissue (Tissue Tech, Inc.), Ocular Surface Center, and Ocular Surface Research & Education Foundation, Miami, FL, 33126 USA
| | - Yuan Zhou
- Department of Pediatric Ophthalmology, Affiliated Hospital of Yunnan University, Kunming 650021, China
| | - Jieying Zhang
- Department of Pediatric Ophthalmology, Affiliated Hospital of Yunnan University, Kunming 650021, China
| | - Xiaofan Zhang
- Department of Pediatric Ophthalmology, Affiliated Hospital of Yunnan University, Kunming 650021, China
| | - Yingting Zhu
- BioTissue (Tissue Tech, Inc.), Ocular Surface Center, and Ocular Surface Research & Education Foundation, Miami, FL, 33126 USA
| | - Liping Xue
- Department of Pediatric Ophthalmology, Affiliated Hospital of Yunnan University, Kunming 650021, China
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24
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Song H, Fisher J, Özen AC, Akin B, Schumann S, Bock M. Quantification of regional CMRO 2 in human brain using dynamic 17O-MRI at 3T. Z Med Phys 2023:S0939-3889(23)00086-7. [PMID: 37558527 DOI: 10.1016/j.zemedi.2023.07.004] [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: 03/31/2023] [Revised: 07/12/2023] [Accepted: 07/14/2023] [Indexed: 08/11/2023]
Abstract
OBJECTIVE To investigate the feasibility of cerebral metabolic rate of oxygen consumption (CMRO2) measurements with MRI at 3 Tesla in different brain regions. METHODS CMRO2 represents a key indicator of the physiological state of brain tissue. Dynamic 17O-MRI with inhalation of isotopically enriched 17O gas has been used to quantify global CMRO2 in brain white (WM) and gray matter (GM). However, global CMRO2 can only reflect the overall oxygen metabolism of the brain and cannot provide enough information on local tissue oxygen metabolism. To investigate the feasibility of determination of regional CMRO2 at a clinical 3 T MRI system, CMRO2 values in frontal, parietal and occipital WM and GM were determined in 5 healthy volunteers and compared to evaluate the regional differences of oxygen metabolism in WM and GM. Additionally, regional CMRO2 values were determined in deep brain structures including thalamus, dorsal striatum, caudate nucleus and insula cortex and in the cerebella, and compared with literature values from 15O-PET studies. RESULTS In cortical GM the determined CMRO2 values were in good agreement with the literature, whereas values in WM were about 32-48% higher than literature values. Regional analysis revealed a significantly higher CMRO2 in the occipital GM compared to the frontal and parietal GM. By contrast, no significant difference of CMRO2 was observed across the WM. In addition, CMRO2 in deep brain structures was lower compared to literature values and in the cerebella a good hemispheric symmetry of the tissue oxygen metabolism was found. CONCLUSION Dynamic 17O-MRI enables direct, non-invasive determination of regional CMRO2 in brain structures in healthy volunteers at 3T.
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Affiliation(s)
- Hao Song
- Division of Medical Physics, Department of Diagnostic and Interventional Radiology, University Medical Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
| | - Johannes Fisher
- Division of Medical Physics, Department of Diagnostic and Interventional Radiology, University Medical Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ali Caglar Özen
- Division of Medical Physics, Department of Diagnostic and Interventional Radiology, University Medical Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Burak Akin
- Section on Functional Imaging Methods, NIMH, NIH, Bethesda, MD, USA
| | - Stefan Schumann
- Department of Anesthesiology and Critical Care, University Medical Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Michael Bock
- Division of Medical Physics, Department of Diagnostic and Interventional Radiology, University Medical Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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25
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Marti-Marca A, Vilà-Balló A, Cerda-Company X, Ikumi N, Torres-Ferrus M, Caronna E, Gallardo VJ, Alpuente A, Torralba Cuello M, Soto-Faraco S, Pozo-Rosich P. Exploring sensory sensitivity, cortical excitability, and habituation in episodic migraine, as a function of age and disease severity, using the pattern-reversal task. J Headache Pain 2023; 24:104. [PMID: 37545005 PMCID: PMC10405481 DOI: 10.1186/s10194-023-01618-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 06/20/2023] [Indexed: 08/08/2023] Open
Abstract
BACKGROUND Migraine is a cyclic, neurosensory disorder characterized by recurrent headaches and altered sensory processing. The latter is manifested in hypersensitivity to visual stimuli, measured with questionnaires and sensory thresholds, as well as in abnormal cortical excitability and a lack of habituation, assessed with visual evoked potentials elicited by pattern-reversal stimulation. Here, the goal was to determine whether factors such as age and/or disease severity may exert a modulatory influence on sensory sensitivity, cortical excitability, and habituation. METHODS Two similar experiments were carried out, the first comparing 24 young, episodic migraine patients and 28 healthy age- and gender-matched controls and the second 36 middle-aged, episodic migraine patients and 30 healthy age- and gender-matched controls. A neurologist confirmed the diagnoses. Migraine phases were obtained using eDiaries. Sensory sensitivity was assessed with the Sensory Perception Quotient and group comparisons were carried out. We obtained pattern-reversal visual evoked potentials and calculated the N1-P1 Peak-to-Peak amplitude. Two linear mixed-effects models were fitted to these data. The first model had Block (first block, last block) and Group (patients, controls) as fixed factors, whereas the second model had Trial (all trials) and Group as fixed factors. Participant was included as a random factor in both. N1-P1 first block amplitude was used to assess cortical excitability and habituation was defined as a decrease of N1-P1 amplitude across Blocks/Trials. Both experiments were performed interictally. RESULTS The final samples consisted of 18 patients with episodic migraine and 27 headache-free controls (first experiment) and 19 patients and 29 controls (second experiment). In both experiments, patients reported increased visual hypersensitivity on the Sensory Perception Quotient as compared to controls. Regarding N1-P1 peak-to-peak data, there was no main effect of Group, indicating no differences in cortical excitability between groups. Finally, significant main effects of both Block and Trial were found indicating habituation in both groups, regardless of age and headache frequency. CONCLUSIONS The results of this study yielded evidence for significant hypersensitivity in patients but no significant differences in either habituation or cortical excitability, as compared to headache-free controls. Although the alterations in patients may be less pronounced than originally anticipated they demonstrate the need for the definition and standardization of optimal methodological parameters.
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Affiliation(s)
- Angela Marti-Marca
- Headache and Neurological Pain Research Group, Vall d'Hebron Institute of Research (VHIR), Department of Medicine, Universitat Autonoma Barcelona, Barcelona, Spain
| | - Adrià Vilà-Balló
- Headache and Neurological Pain Research Group, Vall d'Hebron Institute of Research (VHIR), Department of Medicine, Universitat Autonoma Barcelona, Barcelona, Spain
| | - Xim Cerda-Company
- Headache and Neurological Pain Research Group, Vall d'Hebron Institute of Research (VHIR), Department of Medicine, Universitat Autonoma Barcelona, Barcelona, Spain
| | - Nara Ikumi
- Headache and Neurological Pain Research Group, Vall d'Hebron Institute of Research (VHIR), Department of Medicine, Universitat Autonoma Barcelona, Barcelona, Spain
| | - Marta Torres-Ferrus
- Headache and Neurological Pain Research Group, Vall d'Hebron Institute of Research (VHIR), Department of Medicine, Universitat Autonoma Barcelona, Barcelona, Spain
- Headache Unit, Department of Neurology, Hospital Universitari Vall d'Hebron, Barcelona, Spain
| | - Edoardo Caronna
- Headache and Neurological Pain Research Group, Vall d'Hebron Institute of Research (VHIR), Department of Medicine, Universitat Autonoma Barcelona, Barcelona, Spain
| | - Victor J Gallardo
- Headache and Neurological Pain Research Group, Vall d'Hebron Institute of Research (VHIR), Department of Medicine, Universitat Autonoma Barcelona, Barcelona, Spain
| | - Alicia Alpuente
- Headache and Neurological Pain Research Group, Vall d'Hebron Institute of Research (VHIR), Department of Medicine, Universitat Autonoma Barcelona, Barcelona, Spain
- Headache Unit, Department of Neurology, Hospital Universitari Vall d'Hebron, Barcelona, Spain
| | - Mireia Torralba Cuello
- Multisensory Research Group, Center for Brain and Cognition, Pompeu Fabra University, 08005, Barcelona, Spain
| | - Salvador Soto-Faraco
- Multisensory Research Group, Center for Brain and Cognition, Pompeu Fabra University, 08005, Barcelona, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), 08010, Barcelona, Spain
| | - Patricia Pozo-Rosich
- Headache and Neurological Pain Research Group, Vall d'Hebron Institute of Research (VHIR), Department of Medicine, Universitat Autonoma Barcelona, Barcelona, Spain.
- Headache Unit, Department of Neurology, Hospital Universitari Vall d'Hebron, Barcelona, Spain.
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26
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Wang J, Ji Y, Ai C, Chen JR, Gan D, Zhang J, Mo JQ, Guan MX. Optimized allotopic expression of mitochondrial ND6 transgene restored complex I and apoptosis deficiencies caused by LHON-linked ND6 14484T > C mutation. J Biomed Sci 2023; 30:63. [PMID: 37537557 PMCID: PMC10399063 DOI: 10.1186/s12929-023-00951-1] [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: 03/09/2023] [Accepted: 07/11/2023] [Indexed: 08/05/2023] Open
Abstract
BACKGROUND Leber's hereditary optic neuropathy (LHON) is a maternally inherited eye disease due to mutations in mitochondrial DNA. However, there is no effective treatment for this disease. LHON-linked ND6 14484T > C (p.M64V) mutation caused complex I deficiency, diminished ATP production, increased production of reactive oxygen species (ROS), elevated apoptosis, and impaired mitophagy. Here, we investigated if the allotopic expression of human mitochondrial ND6 transgene corrected the mitochondrial dysfunctions due to LHON-associated m.14484T > C mutation. METHODS Nucleus-versions of ND6 was generated by changing 6 non-universal codons with universal codons and added to mitochondrial targeting sequence of COX8. Stable transfectants were generated by transferring human ND6 cDNA expressed in a pCDH-puro vector into mutant cybrids carrying the m.14484T > C mutation and control cybrids. The effect of allotopic expression of ND6 on oxidative phosphorylation (OXPHOS) was evaluated using Blue Native gel electrophoresis and extracellular flux analyzer. Assessment of ROS production in cell lines was performed by flow cytometry with MitoSOX Red reagent. Analyses for apoptosis and mitophagy were undertaken via flow cytometry, TUNEL and immunofluorescence assays. RESULTS The transfer of human ND6 into the cybrids carrying the m.14484T > C mutation raised the levels of ND6, ND1 and ND4L but did not change the levels of other mitochondrial proteins. The overexpression of ND6 led to 20~23% increases in the assembly and activity of complex I, and ~ 53% and ~ 33% increases in the levels of mitochondrial ATP and ΔΨm in the mutant cybrids bearing m.14484T > C mutation. Furthermore, mutant cybrids with overexpression of ND6 exhibited marked reductions in the levels of mitochondrial ROS. Strikingly, ND6 overexpression markedly inhibited the apoptosis process and restored impaired mitophagy in the cells carrying m.14484T > C mutation. However, overexpression of ND6 did not affect the ND6 level and mitochondrial functions in the wild-type cybrids, indicating that this ND6 level appeared to be the maximum threshold level to maintain the normal cell function. CONCLUSION We demonstrated that allotopic expression of nucleus-versions of ND6 restored complex I, apoptosis and mitophagy deficiencies caused by the m.14484T > C mutation. The restoration of m.14484T > C mutation-induced mitochondrial dysfunctions by overexpression of ND6 is a step toward therapeutic interventions for LHON and mitochondrial diseases.
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Affiliation(s)
- Jing Wang
- Center for Mitochondrial Biomedicine, The Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine and National Clinical Research Center for Child Health, Hangzhou, Zhejiang, China
- Institute of Genetics, Zhejiang University School of Medicine, 866 Yuhangtang Road, Hangzhou, Zhejiang, China
| | - Yanchun Ji
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine and National Clinical Research Center for Child Health, Hangzhou, Zhejiang, China
- Institute of Genetics, Zhejiang University School of Medicine, 866 Yuhangtang Road, Hangzhou, Zhejiang, China
| | - Cheng Ai
- Institute of Genetics, Zhejiang University School of Medicine, 866 Yuhangtang Road, Hangzhou, Zhejiang, China
| | - Jia-Rong Chen
- Center for Mitochondrial Biomedicine, The Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine and National Clinical Research Center for Child Health, Hangzhou, Zhejiang, China
- Institute of Genetics, Zhejiang University School of Medicine, 866 Yuhangtang Road, Hangzhou, Zhejiang, China
| | - Dingyi Gan
- Institute of Genetics, Zhejiang University School of Medicine, 866 Yuhangtang Road, Hangzhou, Zhejiang, China
| | - Juanjuan Zhang
- Institute of Genetics, Zhejiang University School of Medicine, 866 Yuhangtang Road, Hangzhou, Zhejiang, China
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Jun Q Mo
- Department of Pathology, Rady Children's Hospital, University of California at San Diego School of Medicine, San Diego, California, USA
| | - Min-Xin Guan
- Center for Mitochondrial Biomedicine, The Fourth Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine and National Clinical Research Center for Child Health, Hangzhou, Zhejiang, China.
- Institute of Genetics, Zhejiang University School of Medicine, 866 Yuhangtang Road, Hangzhou, Zhejiang, China.
- Zhejiang Provincial Key Laboratory of Genetic and Developmental Disorders, Hangzhou, Zhejiang, China.
- Key Lab of Reproductive Genetics, Ministry of Education of PRC, Zhejiang University, Hangzhou, Zhejiang, China.
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27
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O'Neill AG, Burrell AL, Zech M, Elpeleg O, Harel T, Edvardson S, Mor-Shaked H, Rippert AL, Nomakuchi T, Izumi K, Kollman JM. Neurodevelopmental disorder mutations in the purine biosynthetic enzyme IMPDH2 disrupt its allosteric regulation. J Biol Chem 2023; 299:105012. [PMID: 37414152 PMCID: PMC10407431 DOI: 10.1016/j.jbc.2023.105012] [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: 05/09/2023] [Revised: 06/23/2023] [Accepted: 06/28/2023] [Indexed: 07/08/2023] Open
Abstract
Inosine 5' monophosphate dehydrogenase (IMPDH) is a critical regulatory enzyme in purine nucleotide biosynthesis that is inhibited by the downstream product GTP. Multiple point mutations in the human isoform IMPDH2 have recently been associated with dystonia and other neurodevelopmental disorders, but the effect of the mutations on enzyme function has not been described. Here, we report the identification of two additional missense variants in IMPDH2 from affected individuals and show that all of the disease-associated mutations disrupt GTP regulation. Cryo-EM structures of one IMPDH2 mutant suggest this regulatory defect arises from a shift in the conformational equilibrium toward a more active state. This structural and functional analysis provides insight into IMPDH2-associated disease mechanisms that point to potential therapeutic approaches and raises new questions about fundamental aspects of IMPDH regulation.
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Affiliation(s)
- Audrey G O'Neill
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
| | - Anika L Burrell
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
| | - Michael Zech
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany; Institute of Human Genetics, School of Medicine, Technical University of Munich, Munich, Germany
| | - Orly Elpeleg
- Department of Genetics, Hadassah Medical Center, Jerusalem, Israel; Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Tamar Harel
- Department of Genetics, Hadassah Medical Center, Jerusalem, Israel; Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Simon Edvardson
- Alyn Hospital, Hebrew University School of Medicine, Jerusalem, Israel
| | - Hagar Mor-Shaked
- Department of Genetics, Hadassah Medical Center, Jerusalem, Israel; Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Alyssa L Rippert
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Tomoki Nomakuchi
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Kosuke Izumi
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Justin M Kollman
- Department of Biochemistry, University of Washington, Seattle, Washington, USA.
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28
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Neriyanuri S, Bedggood P, Symons RCA, Metha AB. Flow Heterogeneity and Factors Contributing to the Variability in Retinal Capillary Blood Flow. Invest Ophthalmol Vis Sci 2023; 64:15. [PMID: 37450310 DOI: 10.1167/iovs.64.10.15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2023] Open
Abstract
Purpose Capillary flow plays an important role in the nourishment and maintenance of healthy neural tissue and can be observed directly and non-invasively in the living human retina. Despite their importance, patterns of normal capillary flow are not well understood due to limitations in spatial and temporal resolution of imaging data. Methods Capillary flow characteristics were studied in the retina of three healthy young individuals using a high-resolution adaptive optics ophthalmoscope. Imaging with frame rates of 200 to 300 frames per second was sufficient to capture details of the single-file flow of red blood cells in capillaries over the course of about 3 seconds. Results Erythrocyte velocities were measured from 72 neighboring vessels of the parafoveal capillary network for each subject. We observed strong variability among vessels within a given subject, and even within a given imaged field, across a range of capillary flow parameters including maximum and minimum velocities, pulsatility, abruptness of the systolic peak, and phase of the cardiac cycle. The observed variability was not well explained by "local" factors such as the vessel diameter, tortuosity, length, linear cell density, or hematocrit of the vessel. Within a vessel, a moderate relation between the velocities and hematocrit was noted, suggesting a redistribution of plasma between cells with changes in flow. Conclusions These observations advance our fundamental understanding of normal capillary physiology and raise questions regarding the potential role of network-level effects in explaining the observed flow heterogeneity.
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Affiliation(s)
- Srividya Neriyanuri
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Phillip Bedggood
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - R C Andrew Symons
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
- Department of Surgery, The University of Melbourne, Parkville, Victoria, Australia
- Centre for Eye Research Australia, East Melbourne, Victoria, Australia
- Department of Surgery, Alfred Hospital, Monash University, Melbourne, Victoria, Australia
| | - Andrew B Metha
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
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29
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Wang X, Zhu X, Huang G, Wu L, Meng Z, Wu Y. Knockout of PERK protects rat Müller glial cells against OGD-induced endoplasmic reticulum stress-related apoptosis. BMC Ophthalmol 2023; 23:286. [PMID: 37353739 DOI: 10.1186/s12886-023-03022-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 06/06/2023] [Indexed: 06/25/2023] Open
Abstract
BACKGROUND The pathological basis for many retinal diseases, retinal ischemia is also one of the most common causes of visual impairment. Numerous ocular diseases have been linked to Endoplasmic reticulum(ER)stress. However, there is still no clear understanding of the relationship between ER stress and Müller glial cells during retinal ischemia and hypoxia. This study examined the effects of ER stress on autophagy and apoptosis-related proteins, as well as the microtubule-related protein tau in rMC-1 cells. METHODS rMC-1 cells were cultured in vitro. RT-PCR、immunofluorescence and Western blotting revealed the expression levels of associated mRNAs and proteins, and the CCK-8 and flow cytometry assays detected cell apoptosis. RESULTS The results showed that under OGD(Oxygen-glucose deprivation) conditions, the number of rMC-1 cells was decreased, the PERK/eIF2a pathway was activated, and the expressions of p-tau, LC3、Beclin1 and Caspase-12 proteins were increased. After the PERK knockout, the expression of the above proteins was decreased, and the apoptosis was also decreased. CONCLUSION According to the findings of this study, specific downregulation of PERK expression had an anti-apoptotic effect on OGD-conditioned rMC-1 cells. There is a possibility that this is one of the mechanisms of MG cell apoptosis during retinal ischemic injury.
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Affiliation(s)
- Xiaorui Wang
- Department of Ophthalmology, Second Affiliated Hospital of Fujian Medical University, No.950, Donghai Street, Quanzhou, 362000, Fujian Province, China
| | - Xinxing Zhu
- Department of Ophthalmology, Second Affiliated Hospital of Fujian Medical University, No.950, Donghai Street, Quanzhou, 362000, Fujian Province, China
| | - Guangqian Huang
- Department of Ophthalmology, Second Affiliated Hospital of Fujian Medical University, No.950, Donghai Street, Quanzhou, 362000, Fujian Province, China
| | - Lili Wu
- Department of Ophthalmology, Second Affiliated Hospital of Fujian Medical University, No.950, Donghai Street, Quanzhou, 362000, Fujian Province, China
| | - Zhiyong Meng
- Department of Ophthalmology, Second Affiliated Hospital of Fujian Medical University, No.950, Donghai Street, Quanzhou, 362000, Fujian Province, China
| | - Yuyu Wu
- Department of Ophthalmology, Second Affiliated Hospital of Fujian Medical University, No.950, Donghai Street, Quanzhou, 362000, Fujian Province, China.
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30
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Nag TC, Sharma B, Gorla S. Glycogen in retinal horizontal cells of the African mud catfish Clarias gariepinus (Burchell, 1822) and its physiological significance. Tissue Cell 2023; 83:102140. [PMID: 37329686 DOI: 10.1016/j.tice.2023.102140] [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: 02/17/2023] [Revised: 06/09/2023] [Accepted: 06/10/2023] [Indexed: 06/19/2023]
Abstract
This paper reports on glycogen store in the retinal horizontal cells (HC) of the African mud catfish Clarias gariepinus, as seen by histochemical reaction with periodic acid Schiff (PAS) and transmission electron microscopy in light- as well as dark-adapted state. Glycogen is abundant in the large somata and less in their axons, characterised ultrastructurally by many microtubules and extensive gap junctions interconnecting them. There was no apparent difference in glycogen content in HC somata between light- and dark adaptation, but the axons clearly showed absence of glycogen in dark condition. The HC somata (presynaptic) make synapses with dendrites in the outer plexiform layer. Müller cell inner processes, which contain more densely packed glycogen, invest the HC. Other cells of the inner nuclear layer do not show any appreciable content of glycogen. Rods, but not cones, contain abundant glycogen in their inner segments and synaptic terminals. It is likely that glycogen is used as energy substrate in hypoxia for this species that dwell muddy aquatic environment with low oxygen content. They appear to have high energy demand, and a high glycogen content in HC could act as a ready source to fulfil physiological processes, like microtubule-based transport of cargo from the large somata to axons and the maintenance of electrical activities across the gap junctions between the axonal processes. It is also likely that they can supplement glucose to the neighbouring inner nuclear layer neurons, which are clearly devoid of glycogen.
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Affiliation(s)
- Tapas C Nag
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi, India.
| | - Bhaskar Sharma
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi, India
| | - Shilpa Gorla
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi, India
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Yu DY, Mehnert A, Balaratnasingam C, Yu PK, Hein M, An D, Cringle SJ. An assessment of microvascular hemodynamics in human macula. Sci Rep 2023; 13:7550. [PMID: 37160984 PMCID: PMC10169832 DOI: 10.1038/s41598-023-33490-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 04/13/2023] [Indexed: 05/11/2023] Open
Abstract
An adequate blood supply to meet the energy demands is essential for any tissue, particularly for high energy demand tissues such as the retina. A critical question is: How is the dynamic match between neuronal demands and blood supply achieved? We present a quantitative assessment of temporal and spatial variations in perfusion in the macular capillary network in 10 healthy human subjects using a non-invasive and label-free imaging technique. The assessment is based on the calculation of the coefficient of variation (CoV) of the perfusion signal from arterioles, venules and capillaries from a sequence of optical coherence tomography angiography images centred on the fovea. Significant heterogeneity of the spatial and temporal variation was found within arterioles, venules and capillary networks. The CoV values of the capillaries and smallest vessels were significantly higher than that in the larger vessels. Our results demonstrate the presence of significant heterogeneity of spatial and temporal variation within each element of the macular microvasculature, particularly in the capillaries and finer vessels. Our findings suggest that the dynamic match between neuronal demands and blood supply is achieved by frequent alteration of local blood flow evidenced by capillary perfusion variations both spatially and temporally in the macular region.
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Affiliation(s)
- Dao-Yi Yu
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, Australia.
- Lions Eye Institute, 2 Verdun St, Nedlands, Perth, WA, 6009, Australia.
| | - Andrew Mehnert
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, Australia
- Lions Eye Institute, 2 Verdun St, Nedlands, Perth, WA, 6009, Australia
| | - Chandrakumar Balaratnasingam
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, Australia
- Lions Eye Institute, 2 Verdun St, Nedlands, Perth, WA, 6009, Australia
- Sir Charles Gairdner Hospital, Perth, Australia
| | - Paula K Yu
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, Australia
- Lions Eye Institute, 2 Verdun St, Nedlands, Perth, WA, 6009, Australia
| | - Martin Hein
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, Australia
- Lions Eye Institute, 2 Verdun St, Nedlands, Perth, WA, 6009, Australia
| | - Dong An
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, Australia
- Lions Eye Institute, 2 Verdun St, Nedlands, Perth, WA, 6009, Australia
| | - Stephen J Cringle
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, Australia
- Lions Eye Institute, 2 Verdun St, Nedlands, Perth, WA, 6009, Australia
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Kaynezhad P, Tachtsidis I, Sivaprasad S, Jeffery G. Watching the human retina breath in real time and the slowing of mitochondrial respiration with age. Sci Rep 2023; 13:6445. [PMID: 37081065 PMCID: PMC10119193 DOI: 10.1038/s41598-023-32897-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 04/04/2023] [Indexed: 04/22/2023] Open
Abstract
The retina has the greatest metabolic demand in the body particularly in dark adaptation when its sensitivity is enhanced. This requires elevated level of perfusion to sustain mitochondrial activity. However, mitochondrial performance declines with age leading to reduced adaptive ability. We assessed human retina metabolism in vivo using broad band near-infrared spectroscopy (bNIRS), which records colour changes in mitochondria and blood as retinal metabolism shifts in response to changes in environmental luminance. We demonstrate a significant sustained rise in mitochondrial oxidative metabolism in the first 3 min of darkness in subjects under 50 years old. This was not seen in those over 50 years. Choroidal oxygenation declines in < 50 s as mitochondrial metabolism increases, but gradually rises in the > 50 s. Significant group differences in blood oxygenation are apparent in the first 6 min, consistent with mitochondrial demand leading hemodynamic changes. A greater coupling between mitochondrial oxidative metabolism with hemodynamics is revealed in subjects older than 50, possibly due to reduced capacity in the older retina. Rapid in vivo assessment of retinal metabolism with bNIRS provides a route to understanding fundamental physiology and early identification of retinal disease before pathology is established.
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Affiliation(s)
- Pardis Kaynezhad
- Institute of Ophthalmology, University College London, 11-43 Bath St, London, EC1V9EL, UK
| | - Ilias Tachtsidis
- Department of Medical Physics and Biomedical Engineering, University College London, Gower St, London, WC1E6BT, UK
| | - Sobha Sivaprasad
- Institute of Ophthalmology, University College London, 11-43 Bath St, London, EC1V9EL, UK
| | - Glen Jeffery
- Institute of Ophthalmology, University College London, 11-43 Bath St, London, EC1V9EL, UK.
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O'Neill AG, Burrell AL, Zech M, Elpeleg O, Harel T, Edvardson S, Shaked HM, Rippert AL, Nomakuchi T, Izumi K, Kollman JM. Point mutations in IMPDH2 which cause early-onset neurodevelopmental disorders disrupt enzyme regulation and filament structure. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.15.532669. [PMID: 36993700 PMCID: PMC10055058 DOI: 10.1101/2023.03.15.532669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Inosine 5' monophosphate dehydrogenase (IMPDH) is a critical regulatory enzyme in purine nucleotide biosynthesis that is inhibited by the downstream product GTP. Multiple point mutations in the human isoform IMPDH2 have recently been associated with dystonia and other neurodevelopmental disorders, but the effect of the mutations on enzyme function has not been described. Here, we report identification of two additional affected individuals with missense variants in IMPDH2 and show that all of the disease-associated mutations disrupt GTP regulation. Cryo-EM structures of one IMPDH2 mutant suggest this regulatory defect arises from a shift in the conformational equilibrium toward a more active state. This structural and functional analysis provides insight into IMPDH2-associated disease mechanisms that point to potential therapeutic approaches and raises new questions about fundamental aspects of IMPDH regulation.
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Affiliation(s)
- Audrey G O'Neill
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Anika L Burrell
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Michael Zech
- Institute of Neurogenomics, Helmholtz Zentrum München, 85764 Munich, Germany
- Institute of Human Genetics, School of Medicine, Technical University of Munich, 81675 Munich, Germany
| | - Orly Elpeleg
- Department of Genetics, Hadassah Medical Center, Jerusalem, Israel
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Tamar Harel
- Department of Genetics, Hadassah Medical Center, Jerusalem, Israel
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Simon Edvardson
- Alyn Hospital, Hebrew University School of Medicine, Jerusalem, Israel
| | - Hagar Mor Shaked
- Department of Genetics, Hadassah Medical Center, Jerusalem, Israel
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Alyssa L Rippert
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Tomoki Nomakuchi
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Kosuke Izumi
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Justin M Kollman
- Department of Biochemistry, University of Washington, Seattle, WA, USA
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Todorova V, Stauffacher MF, Ravotto L, Nötzli S, Karademir D, Ebner LJA, Imsand C, Merolla L, Hauck SM, Samardzija M, Saab AS, Barros LF, Weber B, Grimm C. Deficits in mitochondrial TCA cycle and OXPHOS precede rod photoreceptor degeneration during chronic HIF activation. Mol Neurodegener 2023; 18:15. [PMID: 36882871 PMCID: PMC9990367 DOI: 10.1186/s13024-023-00602-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 02/03/2023] [Indexed: 03/09/2023] Open
Abstract
BACKGROUND Major retinal degenerative diseases, including age-related macular degeneration, diabetic retinopathy and retinal detachment, are associated with a local decrease in oxygen availability causing the formation of hypoxic areas affecting the photoreceptor (PR) cells. Here, we addressed the underlying pathological mechanisms of PR degeneration by focusing on energy metabolism during chronic activation of hypoxia-inducible factors (HIFs) in rod PR. METHODS We used two-photon laser scanning microscopy (TPLSM) of genetically encoded biosensors delivered by adeno-associated viruses (AAV) to determine lactate and glucose dynamics in PR and inner retinal cells. Retinal layer-specific proteomics, in situ enzymatic assays and immunofluorescence studies were used to analyse mitochondrial metabolism in rod PRs during chronic HIF activation. RESULTS PRs exhibited remarkably higher glycolytic flux through the hexokinases than neurons of the inner retina. Chronic HIF activation in rods did not cause overt change in glucose dynamics but an increase in lactate production nonetheless. Furthermore, dysregulation of the oxidative phosphorylation pathway (OXPHOS) and tricarboxylic acid (TCA) cycle in rods with an activated hypoxic response decelerated cellular anabolism causing shortening of rod photoreceptor outer segments (OS) before onset of cell degeneration. Interestingly, rods with deficient OXPHOS but an intact TCA cycle did not exhibit these early signs of anabolic dysregulation and showed a slower course of degeneration. CONCLUSION Together, these data indicate an exceeding high glycolytic flux in rods and highlight the importance of mitochondrial metabolism and especially of the TCA cycle for PR survival in conditions of increased HIF activity.
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Affiliation(s)
- Vyara Todorova
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, University of Zurich, Wagistrasse 14, 8952, Schlieren, Switzerland
| | - Mia Fee Stauffacher
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, University of Zurich, Wagistrasse 14, 8952, Schlieren, Switzerland
| | - Luca Ravotto
- Institute of Pharmacology and Toxicology and Neuroscience Center Zurich, University and ETH Zurich, Winterthurerstr. 190, 8057, Zurich, Switzerland
| | - Sarah Nötzli
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, University of Zurich, Wagistrasse 14, 8952, Schlieren, Switzerland
| | - Duygu Karademir
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, University of Zurich, Wagistrasse 14, 8952, Schlieren, Switzerland
| | - Lynn J A Ebner
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, University of Zurich, Wagistrasse 14, 8952, Schlieren, Switzerland
| | - Cornelia Imsand
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, University of Zurich, Wagistrasse 14, 8952, Schlieren, Switzerland
| | - Luca Merolla
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, University of Zurich, Wagistrasse 14, 8952, Schlieren, Switzerland
| | - Stefanie M Hauck
- Metabolomics and Proteomics Core, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Ingolstädter Landstraße 1, 85764, Munich, Germany
| | - Marijana Samardzija
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, University of Zurich, Wagistrasse 14, 8952, Schlieren, Switzerland
| | - Aiman S Saab
- Institute of Pharmacology and Toxicology and Neuroscience Center Zurich, University and ETH Zurich, Winterthurerstr. 190, 8057, Zurich, Switzerland
| | - L Felipe Barros
- Centro de Estudios Científicos (CECs), Valdivia, Chile.,Universidad San Sebastián, Valdivia, Chile
| | - Bruno Weber
- Institute of Pharmacology and Toxicology and Neuroscience Center Zurich, University and ETH Zurich, Winterthurerstr. 190, 8057, Zurich, Switzerland
| | - Christian Grimm
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, University of Zurich, Wagistrasse 14, 8952, Schlieren, Switzerland.
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Abstract
BACKGROUND To describe the clinical presentation with a focus on ocular manifestations and response to riboflavin supplementation of 3 patients with riboflavin transporter deficiency (RTD) caused by mutations in SLC52A2 ( SLC52A2- RTD). METHODS This is a retrospective review of records of 3 children (aged 18, n = 2 and age = 8, n = 1) with SLC52A2- RTD. Patients underwent comprehensive ophthalmic evaluations including color vision testing, pattern visual-evoked potentials (pVEPs, 1 patient) and spectral domain optical coherence tomography (SD-OCT) imaging. Patients received riboflavin supplements from the time of the molecular diagnosis of RTD. RESULTS Two unrelated 18-year-old patients with SLC52A2- RTD had a symptomatic onset with sensorineural hearing loss and auditory neuropathy/dys-synchrony since age 3 and 11, respectively. On examination 7 years after symptomatic onset, they showed subnormal visual acuities (20/30 and 20/60, both eyes, respectively), preserved color vision, and a thin but measurable retinal ganglion cell layer (GCL) and nerve fiber (RNFL). The inner and outer nuclear layers were normal. The asymptomatic SLC52A2- positive brother of one of these patients started riboflavin supplementation right after the molecular diagnosis and had normal vision and SD-OCTs 7 years later. Onset of riboflavin supplementation in one of the 2 symptomatic cases resulted in acute improvement of the pattern visual-evoked potential and vision. CONCLUSIONS Retinal ganglion cells and their axons are uniquely susceptible to RTD compared with other highly energy-dependent retinal neurons, such as photoreceptors, raising the possibility for alternative mechanisms of disease or protection. Riboflavin supplementation results in acute functional improvement of vision and long-term preservation of GCL and RNFL if initiated early.
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Tigert LR, Porteus CS. Invited review - the effects of anthropogenic abiotic stressors on the sensory systems of fishes. Comp Biochem Physiol A Mol Integr Physiol 2023; 277:111366. [PMID: 36586568 DOI: 10.1016/j.cbpa.2022.111366] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Revised: 12/04/2022] [Accepted: 12/27/2022] [Indexed: 12/30/2022]
Abstract
Climate change is a growing global issue with many countries and institutions declaring a climate state of emergency. Excess CO2 from anthropogenic sources and changes in land use practices are contributing to many detrimental changes, including increased global temperatures, ocean acidification and hypoxic zones along coastal habitats. All senses are important for aquatic animals, as it is how they can perceive and respond to their environment. Some of these environmental challenges have been shown to impair their sensory systems, including the olfactory, visual, and auditory systems. While most of the research is focused on how ocean acidification affects olfaction, there is also evidence that it negatively affects vision and hearing. The effects that temperature and hypoxia have on the senses have also been investigated, but to a much lesser extent in comparison to ocean acidification. This review assembles the known information on how these anthropogenic challenges affect the sensory systems of fishes, but also highlights what gaps in knowledge remain with suggestions for immediate action. Olfaction, vision, otolith, pH, freshwater, seawater, marine, central nervous system, electrophysiology, mechanism.
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Affiliation(s)
- Liam R Tigert
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON M1C 1A4, Canada.
| | - Cosima S Porteus
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON M1C 1A4, Canada. https://twitter.com/cosimaporteus
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Abstract
The eye is the window through which light is transmitted and visual sensory signalling originates. It is also a window through which elements of the cardiovascular and nervous systems can be directly inspected, using ophthalmoscopy or retinal imaging. Measurements of ocular parameters may therefore offer important information on the physiology and homeostasis of these two important systems. Here we report the results of a genetic characterisation of retinal vasculature. Four genome-wide association studies performed on different aspects of retinal vasculometry phenotypes, such as arteriolar and venular tortuosity and width, found significant similarities between retinal vascular characteristics and cardiometabolic health. Our analyses identified 119 different regions of association with traits of retinal vasculature, including 89 loci associated arteriolar tortuosity, the strongest of which was rs35131825 (p = 2.00×10-108), 2 loci with arteriolar width (rs12969347, p = 3.30×10-09 and rs5442, p = 1.9E-15), 17 other loci associated with venular tortuosity and 11 novel associations with venular width. Our causal inference analyses also found that factors linked to arteriolar tortuosity cause elevated diastolic blood pressure and not vice versa.
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Elseady WS, Keshk WA, Negm WA, Elkhalawany W, Elhanafy H, Ibrahim MAA, Radwan DA. Saffron extract attenuates Sofosbuvir-induced retinal neurodegeneration in albino rat. Anat Rec (Hoboken) 2023; 306:422-436. [PMID: 35451203 DOI: 10.1002/ar.24942] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 03/27/2022] [Accepted: 04/11/2022] [Indexed: 01/25/2023]
Abstract
Sofosbuvir is a novel drug candidate for the treatment of hepatitis C viral infection; however, vision loss is one of its growing adverse effects. Saffron is a natural biomolecule with a high antioxidant potential that has been efficiently used in some diseases caused by oxidative stress. This study evaluated Sofosbuvir's neurodegenerative effect on the retina of albino rat and examined the potential protective role of saffron aqueous extract. Twenty-one adult male albino rats were randomly divided into three groups: Control, Sofosbuvir-treated (41.1 mg/kg /day for 6 weeks), and Sofosbuvir + Saffron co-treated groups. Retinal specimens were biochemically analyzed for malondialdehyde (MDA), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) levels. In addition, light and transmission electron microscopic examination, as well as immunohistochemical staining for Caspase-3, COX-2, and GFAP were performed. Sofosbuvir treatment caused a significant increase in retinal MDA, IL-6, and TNF-α levels coupling with a significant decrease in retinal total antioxidant capacity level. Histopathological findings revealed disturbed retinal architecture, detached pigment epithelium, vacuolated photoreceptors, in addition to a significant decrease in the thicknesses of both outer and inner nuclear layers, and the number of ganglionic cells. Ultrastructural examination revealed extensive degenerative changes in all retinal layers. Caspase-3, COX-2, and GFAP immunohistochemical expressions were significantly increased. Meanwhile, concomitant treatment with Saffron significantly improved retinal redox status, inflammation, histological, and ultrastructural parameters. Saffron may protect the retina from the hazardous effects of Sofosbuvir. Saffron could be used as an adjuvant therapy to protect patients receiving Sofosbuvir from retinal damage.
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Affiliation(s)
- Walaa S Elseady
- Anatomy and Embryology Department, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Walaa A Keshk
- Department of Medical Biochemistry, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Walaa A Negm
- Pharmacognosy Department, Faculty of Pharmacy, Tanta University, Tanta, Egypt
| | - Walaa Elkhalawany
- Tropical Medicine & Infectious Diseases Department, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Hend Elhanafy
- Anatomy and Embryology Department, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Marwa A A Ibrahim
- Department of Histology and Cell Biology, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Doaa A Radwan
- Anatomy and Embryology Department, Faculty of Medicine, Tanta University, Tanta, Egypt
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Ortega JT, Parmar T, Jastrzebska B. Galanin receptor 3 - A new pharmacological target in retina degeneration. Pharmacol Res 2023; 188:106675. [PMID: 36693600 PMCID: PMC9918719 DOI: 10.1016/j.phrs.2023.106675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 01/16/2023] [Accepted: 01/20/2023] [Indexed: 01/22/2023]
Abstract
The neuropeptide galanin receptor 3 (GALR3) is a class A G protein-coupled receptor (GPCR) broadly expressed in the nervous system, including the retina. GALR3 is involved in the modulation of immune and inflammatory responses. Tight control of these processes is critical for maintaining homeostasis in the retina and is required to sustain vision. Here, we investigated the role of GALR3 in retina pathologies triggered by bright light and P23H mutation in the rhodopsin (RHO) gene, associated with the activation of oxidative stress and inflammatory responses. We used a multiphase approach involving pharmacological inhibition of GALR3 with its antagonist SNAP-37889 and genetic depletion of GALR3 to modulate the GALR3 signaling. Our in vitro experiments in the retinal pigment epithelium-derived cells (ARPE19) susceptible to all-trans-retinal toxicity indicated that GALR3 could be involved in the cellular stress response to this phototoxic product. Indeed, blocking the GALR3 signaling in Abca4-/-/Rdh8-/- and wild-type Balb/cJ mice, sensitive to bright light-induced retina damage, protected retina health in these mice exposed to light. The retina morphology and function were substantially improved, and stress response processes were reduced in these mouse models compared to the controls. Furthermore, in P23H Rho knock-in mice, a model of retinitis pigmentosa (RP), both pharmacological inhibition and genetic ablation of GALR3 prolonged the survival of photoreceptors. These results indicate that GALR3 signaling contributes to acute light-induced and chronic RP-linked retinopathies. Together, this work provides the pharmacological knowledge base to evaluate GALR3 as a potential target for developing novel therapies to combat retinal degeneration.
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Affiliation(s)
- Joseph T Ortega
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44106, USA
| | - Tanu Parmar
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44106, USA
| | - Beata Jastrzebska
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44106, USA.
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Seeing the future: Connectome strength and network efficiency in visual network predict individual ability of episodic future thinking. Neuropsychologia 2023; 179:108451. [PMID: 36535422 DOI: 10.1016/j.neuropsychologia.2022.108451] [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: 04/08/2022] [Revised: 11/10/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022]
Abstract
Episodic future thinking (EFT) refers to the critical ability that enables people to construct and pre-experience the vivid mental imagery about future events, which impacts on the decision-making for individuals and group. Although EFT is generally believed to have a visual nature by theorists, little neuroscience evidence has been provided to verify this assumption. Here, by employing the approach of connectome-based predictive modeling (CPM) and graph-theoretical analysis, we analyzed resting-state functional brain image from 191 participants to predict their variability of EFT ability (leave-one-out cross-validation), and validated the results by applying different parcellation schemas and feature selection thresholds. At the connectome strength level, CPM-based analysis revealed that EFT ability could be predicted by the connectome strength of visual network. Besides, at the network level, graph-theoretical analysis showed that EFT ability could be predicted by the network efficiency of visual network. Moreover, these findings were replicated using different parcellation schemas and feature selection thresholds. These results robustly and collectively supported that the visual network might be one of the neural substrates underlying EFT ability from a comprehensive perspective of resting-state functional connectivity strength and the neural network. This study provides indications on how the function of visual network supports EFT ability, and enhances our understanding of the EFT ability from a neural basis perspective.
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Zheng H, Zhang X, Tian L, Liu B, He X, Wang L, Ding S, Guo Y, Cai J. Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes with an MT-TL1 m.3243A>G point mutation: Neuroradiological features and their implications for underlying pathogenesis. Front Neurosci 2023; 16:1028762. [PMID: 36685235 PMCID: PMC9853426 DOI: 10.3389/fnins.2022.1028762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 12/13/2022] [Indexed: 01/07/2023] Open
Abstract
Objective Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) is one of the most common inherited mitochondrial disorders. Due to the high clinical and genetic heterogeneity of MELAS, it is still a major challenge for clinicians to accurately diagnose the disease at an early stage. Herein, we evaluated the neuroimaging findings of MELAS with an m.3243A>G mutation in MT-TL1 and analyzed the possible underlying pathogenesis of stroke-like episodes. Materials and methods Fifty-nine imaging studies in 24 patients who had a confirmed genetic diagnosis of m.3243A>G (MT-TL1; tRNA Leu) associated with MELAS were reviewed in our case series. The anatomic location, morphological features, signal/intensity characteristics and temporal evolution of lesions were analyzed on magnetic resonance imaging (MRI), and computed tomography (CT) images. The supplying vessels and metabolite content of the lesions were also evaluated by using MR angiography (MRA)/CT angiography (CTA), and MR spectroscopy (MRS), respectively. Results The lesions were most commonly located in the posterior brain, with 37 (37/59, 63%) in the occipital lobe, 32 (32/59, 54%) in the parietal lobe, and 30 (30/59, 51%) in the temporal lobe. The signal characteristics of the lesions varied and evolved over time. Bilateral basal ganglia calcifications were found in 6 of 9 (67%) patients who underwent CT. Cerebral and cerebellar atrophy were found in 38/59 (64%) and 40/59 (68%) patients, respectively. Lesion polymorphism was found in 37/59 (63%) studies. MRS showed elevated lactate doublet peaks in 9/10 (90%) cases. MRA or CTA revealed that the lesion-related arteries were slightly dilated compared with those of the contralateral side in 4 of 6 (67%) cases. Conclusion The imaging features of MELAS vary depending on the disease stage. Polymorphic lesions in a single imaging examination should be considered a diagnostic clue for MELAS. Stroke-like episodes may be involved in a complex pathogenetic process, including mitochondrial angiopathy, mitochondrial cytopathy, and neuronal excitotoxicity.
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Affiliation(s)
- Helin Zheng
- Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Department of Radiology, National Clinical Research Center for Child Health and Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Xuemei Zhang
- Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Department of Medical Affairs, National Clinical Research Center for Child Health and Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Lu Tian
- Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Department of Radiology, National Clinical Research Center for Child Health and Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Bo Liu
- Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Department of Radiology, National Clinical Research Center for Child Health and Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Xiaoya He
- Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Department of Radiology, National Clinical Research Center for Child Health and Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Longlun Wang
- Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Department of Radiology, National Clinical Research Center for Child Health and Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Shuang Ding
- Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Department of Radiology, National Clinical Research Center for Child Health and Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Yi Guo
- Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Department of Pediatric Neurology, National Clinical Research Center for Child Health and Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China,*Correspondence: Yi Guo,
| | - Jinhua Cai
- Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Department of Radiology, National Clinical Research Center for Child Health and Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China,Jinhua Cai,
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Chen Y, Zizmare L, Trautwein C, Paquet-Durand F. Measuring the Release of Lactate from Wild-Type and rd1 Mouse Retina. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1415:429-434. [PMID: 37440068 DOI: 10.1007/978-3-031-27681-1_63] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
The retina has the highest energy consumption of any tissue in the human body. Remarkably, to satisfy its energy demand, the retina appears to rely mostly on aerobic glycolysis, which results in the production and release of large amounts of lactate. In the present study, we compared two different methods to assess lactate release from in vitro organotypic retinal explants cultured under entirely controlled, serum-free conditions. We used a standard lactate assay kit and 1H-nuclear magnetic resonance (NMR) spectroscopy-based analysis. We found that during the culturing of retinal explants derived from wild-type mice, lactate was released in large amounts and that the two different methods agreed well with each other. When comparing wild-type retina with degenerating rd1 mouse retina, we found the latter to release significantly higher amounts of lactate. Hence, degenerating retina may have an even higher energy demand and metabolic rate compared to healthy retina. We conclude that the use of lactate measurement can be a reliable and simple readout to evaluate ongoing retinal metabolism.
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Affiliation(s)
- Yiyi Chen
- Cell Death Mechanism Group, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Laimdota Zizmare
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, University of Tübingen, Tübingen, Germany
| | - Christoph Trautwein
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, University of Tübingen, Tübingen, Germany
| | - François Paquet-Durand
- Cell Death Mechanism Group, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.
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Dumanska H, Veselovsky N. Protein kinase C mediates hypoxia-induced long-term potentiation of NMDA neurotransmission in the visual retinocollicular pathway. Front Cell Neurosci 2023; 17:1141689. [PMID: 36909286 PMCID: PMC9998674 DOI: 10.3389/fncel.2023.1141689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 02/13/2023] [Indexed: 03/14/2023] Open
Abstract
The identification of processes and mechanisms underlying the early stage of hypoxic injury of the retinocollicular pathway may be beneficial for the future prevention and treatment of navigation, orientation, and visual attention impairments. Previously, we have demonstrated that short-term hypoxia led to long-term potentiation (LTP) of NMDA neurotransmission in the background of long-term depression of GABAA retinocollicular transmission. Here, we sought to obtain insight into the mechanisms of hypoxia-induced LTP of NMDA retinocollicular neurotransmission and the role of the protein kinase C (PKC) signaling pathway in it. To investigate these, we recorded pharmacologically isolated NMDA transmission in cocultivated pairs of rat retinal ganglion cells and superficial superior colliculus neurons under normoxic and hypoxic conditions, using the paired patch-clamp technique and method of fast local superfusion. We tested the involvement of the PKC by adding the potent and selective inhibitor chelerythrine chloride (ChC, 5 μM). We observed that hypoxia-induced LTP of NMDA neurotransmission is associated with the shortening of current kinetics. We also found that the PKC signaling pathway mediates hypoxia-induced LTP and associated shortening of NMDA currents. The ChC completely blocked the induction of LTP by hypoxia and associated kinetic changes. Contrary effects of ChC were observed with already induced LTP. ChC led to the reversal of LTP to the initial synaptic strength but the current kinetics remain irreversibly shortened. Our results show that ChC is a promising agent for the prevention and treatment of hypoxic injuries of NMDA retinocollicular neurotransmission and provide necessary electrophysiological basics for further research.
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Affiliation(s)
- Hanna Dumanska
- Department of Neuronal Network Physiology, Bogomoletz Institute of Physiology, National Academy of Science of Ukraine, Kyiv, Ukraine
| | - Nikolai Veselovsky
- Department of Neuronal Network Physiology, Bogomoletz Institute of Physiology, National Academy of Science of Ukraine, Kyiv, Ukraine
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Chen Y, Dong Y, Yan J, Wang L, Yu S, Jiao K, Paquet-Durand F. Single-Cell Transcriptomic Profiling in Inherited Retinal Degeneration Reveals Distinct Metabolic Pathways in Rod and Cone Photoreceptors. Int J Mol Sci 2022; 23:12170. [PMID: 36293024 PMCID: PMC9603353 DOI: 10.3390/ijms232012170] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 09/28/2022] [Accepted: 10/08/2022] [Indexed: 08/31/2023] Open
Abstract
The cellular mechanisms underlying hereditary photoreceptor degeneration are still poorly understood. The aim of this study was to systematically map the transcriptional changes that occur in the degenerating mouse retina at the single cell level. To this end, we employed single-cell RNA-sequencing (scRNA-seq) and retinal degeneration-1 (rd1) mice to profile the impact of the disease mutation on the diverse retinal cell types during early post-natal development. The transcriptome data allowed to annotate 43,979 individual cells grouped into 20 distinct clusters. We further characterized cluster-specific metabolic and biological changes in individual cell types. Our results highlight Ca2+-signaling as relevant to hereditary photoreceptor degeneration. Although metabolic reprogramming in retina, known as the 'Warburg effect', has been documented, further metabolic changes were noticed in rd1 mice. Such metabolic changes in rd1 mutation was likely regulated through mitogen-activated protein kinase (MAPK) pathway. By combining single-cell transcriptomes and immunofluorescence staining, our study revealed cell type-specific changes in gene expression, as well as interplay between Ca2+-induced cell death and metabolic pathways.
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Affiliation(s)
- Yiyi Chen
- Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany
- Graduate Training Centre of Neuroscience, University of Tübingen, 72076 Tübingen, Germany
| | - Yujie Dong
- Yunnan Eye Institute & Key Laboratory of Yunnan Province, 650021 Kunming, China
| | - Jie Yan
- Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany
- Graduate Training Centre of Neuroscience, University of Tübingen, 72076 Tübingen, Germany
| | - Lan Wang
- Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany
- Graduate Training Centre of Neuroscience, University of Tübingen, 72076 Tübingen, Germany
| | - Shirley Yu
- Graduate Training Centre of Neuroscience, University of Tübingen, 72076 Tübingen, Germany
| | - Kangwei Jiao
- Yunnan Eye Institute & Key Laboratory of Yunnan Province, 650021 Kunming, China
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MicroRNA-150 (miR-150) and Diabetic Retinopathy: Is miR-150 Only a Biomarker or Does It Contribute to Disease Progression? Int J Mol Sci 2022; 23:ijms232012099. [PMID: 36292956 PMCID: PMC9603433 DOI: 10.3390/ijms232012099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 10/05/2022] [Accepted: 10/06/2022] [Indexed: 11/18/2022] Open
Abstract
Diabetic retinopathy (DR) is a chronic disease associated with diabetes mellitus and is a leading cause of visual impairment among the working population in the US. Clinically, DR has been diagnosed and treated as a vascular complication, but it adversely impacts both neural retina and retinal vasculature. Degeneration of retinal neurons and microvasculature manifests in the diabetic retina and early stages of DR. Retinal photoreceptors undergo apoptosis shortly after the onset of diabetes, which contributes to the retinal dysfunction and microvascular complications leading to vision impairment. Chronic inflammation is a hallmark of diabetes and a contributor to cell apoptosis, and retinal photoreceptors are a major source of intraocular inflammation that contributes to vascular abnormalities in diabetes. As the levels of microRNAs (miRs) are changed in the plasma and vitreous of diabetic patients, miRs have been suggested as biomarkers to determine the progression of diabetic ocular diseases, including DR. However, few miRs have been thoroughly investigated as contributors to the pathogenesis of DR. Among these miRs, miR-150 is downregulated in diabetic patients and is an endogenous suppressor of inflammation, apoptosis, and pathological angiogenesis. In this review, how miR-150 and its downstream targets contribute to diabetes-associated retinal degeneration and pathological angiogenesis in DR are discussed. Currently, there is no effective treatment to stop or reverse diabetes-caused neural and vascular degeneration in the retina. Understanding the molecular mechanism of the pathogenesis of DR may shed light for the future development of more effective treatments for DR and other diabetes-associated ocular diseases.
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Sladen PE, Jovanovic K, Guarascio R, Ottaviani D, Salsbury G, Novoselova T, Chapple JP, Yu-Wai-Man P, Cheetham ME. Modelling autosomal dominant optic atrophy associated with OPA1 variants in iPSC-derived retinal ganglion cells. Hum Mol Genet 2022; 31:3478-3493. [PMID: 35652445 PMCID: PMC9558835 DOI: 10.1093/hmg/ddac128] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 05/11/2022] [Accepted: 05/26/2022] [Indexed: 11/14/2022] Open
Abstract
Autosomal dominant optic atrophy (DOA) is the most common inherited optic neuropathy, characterized by the preferential loss of retinal ganglion cells (RGCs), resulting in optic nerve degeneration and progressive bilateral central vision loss. More than 60% of genetically confirmed patients with DOA carry variants in the nuclear OPA1 gene, which encodes for a ubiquitously expressed, mitochondrial GTPase protein. OPA1 has diverse functions within the mitochondrial network, facilitating inner membrane fusion and cristae modelling, regulating mitochondrial DNA maintenance and coordinating mitochondrial bioenergetics. There are currently no licensed disease-modifying therapies for DOA and the disease mechanisms driving RGC degeneration are poorly understood. Here, we describe the generation of isogenic, heterozygous OPA1 null induced pluripotent stem cell (iPSC) (OPA1+/-) through clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 gene editing of a control cell line, in conjunction with the generation of DOA patient-derived iPSC carrying OPA1 variants, namely, the c.2708_2711delTTAG variant (DOA iPSC), and previously reported missense variant iPSC line (c.1334G>A, DOA plus [DOA]+ iPSC) and CRISPR/Cas9 corrected controls. A two-dimensional (2D) differentiation protocol was used to study the effect of OPA1 variants on iPSC-RGC differentiation and mitochondrial function. OPA1+/-, DOA and DOA+ iPSC showed no differentiation deficit compared to control iPSC lines, exhibiting comparable expression of all relevant markers at each stage of differentiation. OPA1+/- and OPA1 variant iPSC-RGCs exhibited impaired mitochondrial homeostasis, with reduced bioenergetic output and compromised mitochondrial DNA maintenance. These data highlight mitochondrial deficits associated with OPA1 dysfunction in human iPSC-RGCs, and establish a platform to study disease mechanisms that contribute to RGC loss in DOA, as well as potential therapeutic interventions.
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Affiliation(s)
- Paul E Sladen
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | | | | | - Daniele Ottaviani
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
- Department of Biology, University of Padua, and Veneto Institute of Molecular Medicine, Padua 35129, Italy
| | - Grace Salsbury
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UK
| | - Tatiana Novoselova
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UK
| | - J Paul Chapple
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UK
| | - Patrick Yu-Wai-Man
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
- Cambridge Eye Unit, Addenbrooke’s Hospital, Cambridge University Hospital, Cambridge CB2 0QQ, UK
- Cambridge Centre for Brain Repair and MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0PY, UK
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McCormick LR, Levin LA, Oesch NW. Reduced Oxygen Impairs Photobehavior in Marine Invertebrate Larvae. THE BIOLOGICAL BULLETIN 2022; 243:255-271. [PMID: 36548968 DOI: 10.1086/717565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
AbstractOrganisms in coastal waters experience naturally high oxygen variability and steep oxygen gradients with depth, in addition to ocean deoxygenation. They often undergo diel vertical migration involving a change in irradiance that initiates a visual behavior. Retinal function has been shown to be highly sensitive to oxygen loss; here we assess whether visual behavior (photobehavior) in paralarvae of the squid Doryteuthis opalescens and the octopus Octopus bimaculatus is affected by low oxygen conditions, using a novel behavioral paradigm. Larvae showed an irradiance-dependent, descending photobehavior after extinction of the light stimulus, measured through the change in vertical position of larvae in the chamber. The magnitude of photobehavior was decreased as oxygen was reduced, and the response was entirely gone at <6.4 kPa partial pressure of oxygen (<74.7 μmol kg-1 at 15.3 °C) in D. opalescens paralarvae. Oxygen also affected photobehavior in O. bimaculatus paralarvae. The mean vertical velocity of paralarvae was unaffected by exposure to reduced oxygen, indicating that oxygen deficits selectively affect vision prior to locomotion. These findings suggest that variable and declining oxygen conditions in coastal upwelling areas and elsewhere will impair photobehavior and likely affect the distribution, migration behavior, and survival of highly visual marine species.
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Van Hook MJ. Influences of Glaucoma on the Structure and Function of Synapses in the Visual System. Antioxid Redox Signal 2022; 37:842-861. [PMID: 35044228 PMCID: PMC9587776 DOI: 10.1089/ars.2021.0253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 12/31/2021] [Indexed: 11/12/2022]
Abstract
Significance: Glaucoma is an age-related neurodegenerative disorder of the visual system associated with sensitivity to intraocular pressure (IOP). It is the leading irreversible cause of vision loss worldwide, and vision loss results from damage and dysfunction of the retinal output neurons known as retinal ganglion cells (RGCs). Recent Advances: Elevated IOP and optic nerve injury triggers pruning of RGC dendrites, altered morphology of excitatory inputs from presynaptic bipolar cells, and disrupted RGC synaptic function. Less is known about RGC outputs, although evidence to date indicates that glaucoma is associated with altered mitochondrial and synaptic structure and function in RGC-projection targets in the brain. These early functional changes likely contribute to vision loss and might be a window into early diagnosis and treatment. Critical Issues: Glaucoma affects different RGC populations to varying extents and along distinct time courses. The influence of glaucoma on RGC synaptic function as well as the mechanisms underlying these effects remain to be determined. Since RGCs are an especially energetically demanding population of neurons, altered intracellular axon transport of mitochondria and mitochondrial function might contribute to RGC synaptic dysfunction in the retina and brain as well as RGC vulnerability in glaucoma. Future Directions: The mechanisms underlying differential RGC vulnerability remain to be determined. Moreover, the timing and mechanisms of RGCs synaptic dysfunction and degeneration will provide valuable insight into the disease process in glaucoma. Future work will be able to capitalize on these findings to better design diagnostic and therapeutic approaches to detect disease and prevent vision loss. Antioxid. Redox Signal. 37, 842-861.
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Affiliation(s)
- Matthew J. Van Hook
- Department of Ophthalmology & Visual Science and Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, Nebraska, USA
- Department of Cellular & Integrative Physiology, Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, Nebraska, USA
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Buey RM, Fernández‐Justel D, Jiménez A, Revuelta JL. The gateway to guanine nucleotides: Allosteric regulation of IMP dehydrogenases. Protein Sci 2022; 31:e4399. [PMID: 36040265 PMCID: PMC9375230 DOI: 10.1002/pro.4399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 07/07/2022] [Accepted: 07/19/2022] [Indexed: 11/12/2022]
Abstract
Inosine 5′‐monophosphate dehydrogenase (IMPDH) is an evolutionarily conserved enzyme that mediates the first committed step in de novo guanine nucleotide biosynthetic pathway. It is an essential enzyme in purine nucleotide biosynthesis that modulates the metabolic flux at the branch point between adenine and guanine nucleotides. IMPDH plays key roles in cell homeostasis, proliferation, and the immune response, and is the cellular target of several drugs that are widely used for antiviral and immunosuppressive chemotherapy. IMPDH enzyme is tightly regulated at multiple levels, from transcriptional control to allosteric modulation, enzyme filamentation, and posttranslational modifications. Herein, we review recent developments in our understanding of the mechanisms of IMPDH regulation, including all layers of allosteric control that fine‐tune the enzyme activity.
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Affiliation(s)
- Rubén M. Buey
- Metabolic Engineering Group, Department of Microbiology and Genetics Universidad de Salamanca Salamanca Spain
| | - David Fernández‐Justel
- Metabolic Engineering Group, Department of Microbiology and Genetics Universidad de Salamanca Salamanca Spain
| | - Alberto Jiménez
- Metabolic Engineering Group, Department of Microbiology and Genetics Universidad de Salamanca Salamanca Spain
| | - José L. Revuelta
- Metabolic Engineering Group, Department of Microbiology and Genetics Universidad de Salamanca Salamanca Spain
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