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Garcia-Sanchez J, Lin D, Liu WW. Mechanosensitive ion channels in glaucoma pathophysiology. Vision Res 2024; 223:108473. [PMID: 39180975 PMCID: PMC11398070 DOI: 10.1016/j.visres.2024.108473] [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: 06/17/2024] [Revised: 08/05/2024] [Accepted: 08/07/2024] [Indexed: 08/27/2024]
Abstract
Force sensing is a fundamental ability that allows cells and organisms to interact with their physical environment. The eye is constantly subjected to mechanical forces such as blinking and eye movements. Furthermore, elevated intraocular pressure (IOP) can cause mechanical strain at the optic nerve head, resulting in retinal ganglion cell death (RGC) in glaucoma. How mechanical stimuli are sensed and affect cellular physiology in the eye is unclear. Recent studies have shown that mechanosensitive ion channels are expressed in many ocular tissues relevant to glaucoma and may influence IOP regulation and RGC survival. Furthermore, variants in mechanosensitive ion channel genes may be associated with risk for primary open angle glaucoma. These findings suggest that mechanosensitive channels may be important mechanosensors mediating cellular responses to pressure signals in the eye. In this review, we focus on mechanosensitive ion channels from three major channel families-PIEZO, two-pore potassium and transient receptor potential channels. We review the key properties of these channels, their effects on cell function and physiology, and discuss their possible roles in glaucoma pathophysiology.
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Affiliation(s)
- Julian Garcia-Sanchez
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Danting Lin
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Wendy W Liu
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA.
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2
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Akiba R, Lind Boniec S, Knecht S, Uyama H, Tu HY, Baba T, Takahashi M, Mandai M, Wong RO. Cellular and circuit remodeling of the primate foveal midget pathway after acute photoreceptor loss. Proc Natl Acad Sci U S A 2024; 121:e2413104121. [PMID: 39231211 PMCID: PMC11406236 DOI: 10.1073/pnas.2413104121] [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: 06/30/2024] [Accepted: 08/01/2024] [Indexed: 09/06/2024] Open
Abstract
The retinal fovea in human and nonhuman primates is essential for high acuity and color vision. Within the fovea lies specialized circuitry in which signals from a single cone photoreceptor are largely conveyed to one ON and one OFF type midget bipolar cell (MBC), which in turn connect to a single ON or OFF midget ganglion cell (MGC), respectively. Restoring foveal vision requires not only photoreceptor replacement but also appropriate reconnection with surviving ON and OFF MBCs and MGCs. However, our current understanding of the effects of cone loss on the remaining foveal midget pathway is limited. We thus used serial block-face electron microscopy to determine the degree of plasticity and potential remodeling of this pathway in adult Macaca fascicularis several months after acute photoreceptor loss upon photocoagulation. We reconstructed MBC structure and connectivity within and adjacent to the region of cone loss. We found that MBC dendrites within the scotoma retracted and failed to reach surviving cones to form new connections. However, both surviving cones and ON and OFF MBC dendrites at the scotoma border exhibited remodeling, suggesting that these neurons can demonstrate plasticity and rewiring at maturity. At six months postlesion, disconnected OFF MBCs clearly lost output ribbon synapses with their postsynaptic partners, whereas the majority of ON MBCs maintained their axonal ribbon numbers, suggesting differential timing or extent in ON and OFF midget circuit remodeling after cone loss. Our findings raise rewiring considerations for cell replacement approaches in the restoration of foveal vision.
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Affiliation(s)
- Ryutaro Akiba
- Department of Biological Structure, University of Washington, Seattle, WA 98195
- Laboratory for Retinal Regeneration, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan
- Department of Ophthalmology and Visual Sciences, Chiba University Graduate School of Medicine, Chiba 260-8677, Japan
| | - Shane Lind Boniec
- Department of Biological Structure, University of Washington, Seattle, WA 98195
| | - Sharm Knecht
- Department of Biological Structure, University of Washington, Seattle, WA 98195
| | - Hirofumi Uyama
- Laboratory for Retinal Regeneration, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan
| | - Hung-Ya Tu
- Laboratory for Retinal Regeneration, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Osaka 565-0871, Japan
| | - Takayuki Baba
- Department of Ophthalmology and Visual Sciences, Chiba University Graduate School of Medicine, Chiba 260-8677, Japan
| | - Masayo Takahashi
- Laboratory for Retinal Regeneration, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan
- Research Center, Kobe City Eye Hospital Research Center, Kobe, Hyogo 650-0047, Japan
| | - Michiko Mandai
- Laboratory for Retinal Regeneration, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan
- Research Center, Kobe City Eye Hospital Research Center, Kobe, Hyogo 650-0047, Japan
| | - Rachel O Wong
- Department of Biological Structure, University of Washington, Seattle, WA 98195
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Scott MTW, Xu H, Yakovleva A, Tibshirani R, Goldberg JL, Norcia AM. Glaucoma classification through SSVEP derived ON- and OFF-pathway features. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.08.22.24312443. [PMID: 39228700 PMCID: PMC11370506 DOI: 10.1101/2024.08.22.24312443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/05/2024]
Abstract
Recent evidence from small animal models and human electrophysiology suggests that the OFF-pathway is more vulnerable to glaucomatous insult than the ON-pathway. Thus, OFF-pathway based measurements of visual function may be useful in the diagnosis of Glaucoma. The steady-state visually evoked potential (SSVEP) can be used to non-invasively make such functional measurements. Here, we examine whether OFF- and ON-pathway biasing SSVEP measurements differently predict glaucoma diagnosis using a large cohort of 98 glaucoma patients and 71 controls. Using both a logistic regression with k-fold cross-validation and a random forest classifier, we show that OFF-pathway biasing features produce a small improvement in predictive accuracy over ON-pathway biasing features. However, despite our inclusion of many more response features and the retention of both participants' eyes, our classifier did not perform as well as previous reports that used the isolated-check VEP. This is likely a result of the relatively small amount of data we collected for each participant, but may also be explained by the absence of any train-test splitting in preexisting work. Nevertheless, our results support further exploration of the diagnostic potential of OFF-pathway biasing functional biomarkers for glaucoma.
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Affiliation(s)
| | - Hui Xu
- Department of Statistics, Stanford University
| | - Alexandra Yakovleva
- Spencer Center for Vision Research, Byers Eye Institute, Department of Ophthalmology, Stanford University
| | | | - Jeffrey L Goldberg
- Spencer Center for Vision Research, Byers Eye Institute, Department of Ophthalmology, Stanford University
| | - Anthony M Norcia
- Wu-Tsai Neurosciences Institute, Department of Psychology, Stanford University
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4
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El Hajji S, Shiga Y, Belforte N, Solorio YC, Tastet O, D’Onofrio P, Dotigny F, Prat A, Arbour N, Fortune B, Di Polo A. Insulin restores retinal ganglion cell functional connectivity and promotes visual recovery in glaucoma. SCIENCE ADVANCES 2024; 10:eadl5722. [PMID: 39110798 PMCID: PMC11305393 DOI: 10.1126/sciadv.adl5722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Accepted: 06/28/2024] [Indexed: 08/10/2024]
Abstract
Dendrite pathology and synaptic loss result in neural circuit dysfunction, a common feature of neurodegenerative diseases. There is a lack of strategies that target dendritic and synaptic regeneration to promote neurorecovery. We show that daily human recombinant insulin eye drops stimulate retinal ganglion cell (RGC) dendrite and synapse regeneration during ocular hypertension, a risk factor to develop glaucoma. We demonstrate that the ribosomal protein p70S6 kinase (S6K) is essential for insulin-dependent dendritic regrowth. Furthermore, S6K phosphorylation of the stress-activated protein kinase-interacting protein 1 (SIN1), a link between the mammalian target of rapamycin complexes 1 and 2 (mTORC1/2), is required for insulin-induced dendritic regeneration. Using two-photon microscopy live retinal imaging, we show that insulin rescues single-RGC light-evoked calcium (Ca2+) dynamics. We further demonstrate that insulin enhances neuronal survival and retina-brain connectivity leading to improved optomotor reflex-elicited behaviors. Our data support that insulin is a compelling pro-regenerative strategy with potential clinical implications for the treatment and management of glaucoma.
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Affiliation(s)
- Sana El Hajji
- Department of Neuroscience, Université de Montréal, PO box 6128, Station centre-ville, Montreal, Quebec, Canada
- Neuroscience Division, Centre de recherche du Centre Hospitalier de l’Université de Montréal (CR-CHUM), 900 Saint Denis Street, Montreal, Quebec, Canada
| | - Yukihiro Shiga
- Department of Neuroscience, Université de Montréal, PO box 6128, Station centre-ville, Montreal, Quebec, Canada
- Neuroscience Division, Centre de recherche du Centre Hospitalier de l’Université de Montréal (CR-CHUM), 900 Saint Denis Street, Montreal, Quebec, Canada
| | - Nicolas Belforte
- Department of Neuroscience, Université de Montréal, PO box 6128, Station centre-ville, Montreal, Quebec, Canada
- Neuroscience Division, Centre de recherche du Centre Hospitalier de l’Université de Montréal (CR-CHUM), 900 Saint Denis Street, Montreal, Quebec, Canada
| | - Yves Carpentier Solorio
- Department of Neuroscience, Université de Montréal, PO box 6128, Station centre-ville, Montreal, Quebec, Canada
- Neuroscience Division, Centre de recherche du Centre Hospitalier de l’Université de Montréal (CR-CHUM), 900 Saint Denis Street, Montreal, Quebec, Canada
| | - Olivier Tastet
- Department of Neuroscience, Université de Montréal, PO box 6128, Station centre-ville, Montreal, Quebec, Canada
- Neuroscience Division, Centre de recherche du Centre Hospitalier de l’Université de Montréal (CR-CHUM), 900 Saint Denis Street, Montreal, Quebec, Canada
| | - Philippe D’Onofrio
- Department of Neuroscience, Université de Montréal, PO box 6128, Station centre-ville, Montreal, Quebec, Canada
- Neuroscience Division, Centre de recherche du Centre Hospitalier de l’Université de Montréal (CR-CHUM), 900 Saint Denis Street, Montreal, Quebec, Canada
| | - Florence Dotigny
- Department of Neuroscience, Université de Montréal, PO box 6128, Station centre-ville, Montreal, Quebec, Canada
- Neuroscience Division, Centre de recherche du Centre Hospitalier de l’Université de Montréal (CR-CHUM), 900 Saint Denis Street, Montreal, Quebec, Canada
| | - Alexandre Prat
- Department of Neuroscience, Université de Montréal, PO box 6128, Station centre-ville, Montreal, Quebec, Canada
- Neuroscience Division, Centre de recherche du Centre Hospitalier de l’Université de Montréal (CR-CHUM), 900 Saint Denis Street, Montreal, Quebec, Canada
| | - Nathalie Arbour
- Department of Neuroscience, Université de Montréal, PO box 6128, Station centre-ville, Montreal, Quebec, Canada
- Neuroscience Division, Centre de recherche du Centre Hospitalier de l’Université de Montréal (CR-CHUM), 900 Saint Denis Street, Montreal, Quebec, Canada
| | - Brad Fortune
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Health, Portland, OR, USA
| | - Adriana Di Polo
- Department of Neuroscience, Université de Montréal, PO box 6128, Station centre-ville, Montreal, Quebec, Canada
- Neuroscience Division, Centre de recherche du Centre Hospitalier de l’Université de Montréal (CR-CHUM), 900 Saint Denis Street, Montreal, Quebec, Canada
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5
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Du R, Wang P, Tian N. CD3ζ-Mediated Signaling Protects Retinal Ganglion Cells in Glutamate Excitotoxicity of the Retina. Cells 2024; 13:1006. [PMID: 38920637 PMCID: PMC11201742 DOI: 10.3390/cells13121006] [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: 03/30/2024] [Revised: 05/28/2024] [Accepted: 06/06/2024] [Indexed: 06/27/2024] Open
Abstract
Excessive levels of glutamate activity could potentially damage and kill neurons. Glutamate excitotoxicity is thought to play a critical role in many CNS and retinal diseases. Accordingly, glutamate excitotoxicity has been used as a model to study neuronal diseases. Immune proteins, such as major histocompatibility complex (MHC) class I molecules and their receptors, play important roles in many neuronal diseases, while T-cell receptors (TCR) are the primary receptors of MHCI. We previously showed that a critical component of TCR, CD3ζ, is expressed by mouse retinal ganglion cells (RGCs). The mutation of CD3ζ or MHCI molecules compromises the development of RGC structure and function. In this study, we investigated whether CD3ζ-mediated molecular signaling regulates RGC death in glutamate excitotoxicity. We show that mutation of CD3ζ significantly increased RGC survival in NMDA-induced excitotoxicity. In addition, we found that several downstream molecules of TCR, including Src (proto-oncogene tyrosine-protein kinase) family kinases (SFKs) and spleen tyrosine kinase (Syk), are expressed by RGCs. Selective inhibition of an SFK member, Hck, or Syk members, Syk or Zap70, significantly increased RGC survival in NMDA-induced excitotoxicity. These results provide direct evidence to reveal the underlying molecular mechanisms that control RGC death under disease conditions.
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Affiliation(s)
- Rui Du
- Department of Ophthalmology and Visual Science, University of Utah School of Medicine, Salt Lake City, UT 84132, USA; (R.D.); (P.W.)
| | - Ping Wang
- Department of Ophthalmology and Visual Science, University of Utah School of Medicine, Salt Lake City, UT 84132, USA; (R.D.); (P.W.)
| | - Ning Tian
- Department of Ophthalmology and Visual Science, University of Utah School of Medicine, Salt Lake City, UT 84132, USA; (R.D.); (P.W.)
- Department of Neurobiology, University of Utah, Salt Lake City, UT 84132, USA
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84132, USA
- Veterans Affairs Medical Center, Salt Lake City, UT 84148, USA
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Tsai YC, Lee HP, Tsung TH, Chen YH, Lu DW. Unveiling Novel Structural Biomarkers for the Diagnosis of Glaucoma. Biomedicines 2024; 12:1211. [PMID: 38927418 PMCID: PMC11200849 DOI: 10.3390/biomedicines12061211] [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: 04/29/2024] [Revised: 05/21/2024] [Accepted: 05/28/2024] [Indexed: 06/28/2024] Open
Abstract
Glaucoma, a leading cause of irreversible blindness, poses a significant global health burden. Early detection is crucial for effective management and prevention of vision loss. This study presents a collection of novel structural biomarkers in glaucoma diagnosis. By employing advanced imaging techniques and data analysis algorithms, we now can recognize indicators of glaucomatous progression. Many research studies have revealed a correlation between the structural changes in the eye or brain, particularly in the optic nerve head and retinal nerve fiber layer, and the progression of glaucoma. These biomarkers demonstrate value in distinguishing glaucomatous eyes from healthy ones, even in the early stages of the disease. By facilitating timely detection and monitoring, they hold the potential to mitigate vision impairment and improve patient outcomes. This study marks an advancement in the field of glaucoma, offering a promising avenue for enhancing the diagnosis and possible management.
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Affiliation(s)
- Yu-Chien Tsai
- Department of Ophthalmology, Tri-Service General Hospital, National Defense Medical Center, Taipei 114, Taiwan
- Department of Ophthalmology, Taoyuan Armed Forces General Hospital, Taoyuan 325, Taiwan
| | - Hsin-Pei Lee
- Department of Ophthalmology, Tri-Service General Hospital, National Defense Medical Center, Taipei 114, Taiwan
| | - Ta-Hsin Tsung
- Department of Ophthalmology, Tri-Service General Hospital, National Defense Medical Center, Taipei 114, Taiwan
| | - Yi-Hao Chen
- Department of Ophthalmology, Tri-Service General Hospital, National Defense Medical Center, Taipei 114, Taiwan
| | - Da-Wen Lu
- Department of Ophthalmology, Tri-Service General Hospital, National Defense Medical Center, Taipei 114, Taiwan
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7
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Becker S, L'Ecuyer Z, Jones BW, Zouache MA, McDonnell FS, Vinberg F. Modeling complex age-related eye disease. Prog Retin Eye Res 2024; 100:101247. [PMID: 38365085 PMCID: PMC11268458 DOI: 10.1016/j.preteyeres.2024.101247] [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: 08/15/2023] [Revised: 01/31/2024] [Accepted: 02/02/2024] [Indexed: 02/18/2024]
Abstract
Modeling complex eye diseases like age-related macular degeneration (AMD) and glaucoma poses significant challenges, since these conditions depend highly on age-related changes that occur over several decades, with many contributing factors remaining unknown. Although both diseases exhibit a relatively high heritability of >50%, a large proportion of individuals carrying AMD- or glaucoma-associated genetic risk variants will never develop these diseases. Furthermore, several environmental and lifestyle factors contribute to and modulate the pathogenesis and progression of AMD and glaucoma. Several strategies replicate the impact of genetic risk variants, pathobiological pathways and environmental and lifestyle factors in AMD and glaucoma in mice and other species. In this review we will primarily discuss the most commonly available mouse models, which have and will likely continue to improve our understanding of the pathobiology of age-related eye diseases. Uncertainties persist whether small animal models can truly recapitulate disease progression and vision loss in patients, raising doubts regarding their usefulness when testing novel gene or drug therapies. We will elaborate on concerns that relate to shorter lifespan, body size and allometries, lack of macula and a true lamina cribrosa, as well as absence and sequence disparities of certain genes and differences in their chromosomal location in mice. Since biological, rather than chronological, age likely predisposes an organism for both glaucoma and AMD, more rapidly aging organisms like small rodents may open up possibilities that will make research of these diseases more timely and financially feasible. On the other hand, due to the above-mentioned anatomical and physiological features, as well as pharmacokinetic and -dynamic differences small animal models are not ideal to study the natural progression of vision loss or the efficacy and safety of novel therapies. In this context, we will also discuss the advantages and pitfalls of alternative models that include larger species, such as non-human primates and rabbits, patient-derived retinal organoids, and human organ donor eyes.
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Affiliation(s)
- Silke Becker
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
| | - Zia L'Ecuyer
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
| | - Bryan W Jones
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
| | - Moussa A Zouache
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
| | - Fiona S McDonnell
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA; Biomedical Engineering, University of Utah, Salt Lake City, UT, USA
| | - Frans Vinberg
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA; Biomedical Engineering, University of Utah, Salt Lake City, UT, USA.
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8
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Pang JJ. The Variety of Mechanosensitive Ion Channels in Retinal Neurons. Int J Mol Sci 2024; 25:4877. [PMID: 38732096 PMCID: PMC11084373 DOI: 10.3390/ijms25094877] [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: 02/27/2024] [Revised: 04/16/2024] [Accepted: 04/20/2024] [Indexed: 05/13/2024] Open
Abstract
Alterations in intraocular and external pressure critically involve the pathogenesis of glaucoma, traumatic retinal injury (TRI), and other retinal disorders, and retinal neurons have been reported to express multiple mechanical-sensitive channels (MSCs) in recent decades. However, the role of MSCs in visual functions and pressure-related retinal conditions has been unclear. This review will focus on the variety and functional significance of the MSCs permeable to K+, Na+, and Ca2+, primarily including the big potassium channel (BK); the two-pore domain potassium channels TRAAK and TREK; Piezo; the epithelial sodium channel (ENaC); and the transient receptor potential channels vanilloid TRPV1, TRPV2, and TRPV4 in retinal photoreceptors, bipolar cells, horizontal cells, amacrine cells, and ganglion cells. Most MSCs do not directly mediate visual signals in vertebrate retinas. On the other hand, some studies have shown that MSCs can open in physiological conditions and regulate the activities of retinal neurons. While these data reasonably predict the crossing of visual and mechanical signals, how retinal light pathways deal with endogenous and exogenous mechanical stimulation is uncertain.
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Affiliation(s)
- Ji-Jie Pang
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX 77030, USA
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Fahrenthold BK, Cavanaugh MR, Tamhankar M, Lam BL, Feldon SE, Johnson BA, Huxlin KR. Training in Cortically Blinded Fields Appears to Confer Patient-Specific Benefit Against Retinal Thinning. Invest Ophthalmol Vis Sci 2024; 65:29. [PMID: 38635245 PMCID: PMC11033601 DOI: 10.1167/iovs.65.4.29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 03/06/2024] [Indexed: 04/19/2024] Open
Abstract
Purpose Damage to the adult primary visual cortex (V1) causes vision loss in the contralateral hemifield, initiating a process of transsynaptic retrograde degeneration (TRD). Here, we examined retinal correlates of TRD using a new metric to account for global changes in inner retinal thickness and asked if perceptual training in the intact or blind field impacts its progression. Methods We performed a meta-analysis of optical coherence tomography data in 48 participants with unilateral V1 stroke and homonymous visual defects who completed clinical trial NCT03350919. After measuring the thickness of the macular ganglion cell and inner plexiform layer (GCL-IPL) and the peripapillary retinal nerve fiber layer (RNFL), we computed individual laterality indices (LI) at baseline and after ∼6 months of daily motion discrimination training in the intact or blind field. Increasingly positive LI denoted greater layer thinning in retinal regions affected versus unaffected by the cortical damage. Results Pretraining, the affected GCL-IPL and RNFL were thinner than their unaffected counterparts, generating LI values positively correlated with time since stroke. Participants trained in their intact field exhibited increased LIGCL-IPL. Those trained in their blind field had no significant change in LIGCL-IPL. LIRNFL did not change in either group. Conclusions Relative shrinkage of the affected versus unaffected macular GCL-IPL can be reliably measured at an individual level and increases with time post-V1 stroke. Relative thinning progressed during intact-field training but appeared to be halted by training within the blind field, suggesting a potentially neuroprotective effect of this simple behavioral intervention.
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Affiliation(s)
- Berkeley K. Fahrenthold
- Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, New York, United States
| | - Matthew R. Cavanaugh
- Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, New York, United States
| | - Madhura Tamhankar
- Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Byron L. Lam
- Bascom Palmer Eye Institute, University of Miami, Miami, Florida, United States
| | - Steven E. Feldon
- Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, New York, United States
| | - Brent A. Johnson
- Department of Biostatistics and Computational Biology, University of Rochester, Rochester, New York, United States
| | - Krystel R. Huxlin
- Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, New York, United States
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10
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Ji S, Peng Y, Liu J, Xu P, Tang S. Human adipose tissue-derived stem cell extracellular vesicles attenuate ocular hypertension-induced retinal ganglion cell damage by inhibiting microglia- TLR4/MAPK/NF-κB proinflammatory cascade signaling. Acta Neuropathol Commun 2024; 12:44. [PMID: 38504301 PMCID: PMC10953184 DOI: 10.1186/s40478-024-01753-8] [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: 01/22/2024] [Accepted: 03/07/2024] [Indexed: 03/21/2024] Open
Abstract
Microglia-mediated neuroinflammatory responses are recognized as a predominant factor during high intraocular pressure (IOP)-induced retinal and optic nerve injury along with potential therapeutic targets for the disease. Our previous research indicated that mesenchymal stem cell (MSC) treatment could reduce high IOP-induced neuroinflammatory responses through the TLR4 pathway in a rat model without apparent cell replacement and differentiation, suggesting that the anti-neuroinflammatory properties of MSCs are potentially mediated by paracrine signaling. This study aimed to evaluate the anti-neuroinflammatory effect of human adipose tissue-derived extracellular vesicles (ADSC-EVs) in microbead-induced ocular hypertension (OHT) animals and to explore the underlying mechanism since extracellular vesicles (EVs) are the primary transporters for cell secretory action. The anti-neuroinflammatory effect of ADSC-EVs on LPS-stimulated BV-2 cells in vitro and OHT-induced retinal and optic nerve injury in vivo was investigated. According to the in vitro research, ADSC-EV treatment reduced LPS-induced microglial activation and the TLR4/NF-κB proinflammatory cascade response axis in BV-2 cells, such as CD68, iNOS, TNF-α, IL-6, and IL-1β, TLR4, p-38 MAPK, NF-κB. According to the in vivo data, intravitreal injection of ADSC-EVs promoted RGC survival and function, reduced microglial activation, microglial-derived neuroinflammatory responses, and TLR4/MAPK/NF-κB proinflammatory cascade response axis in the OHT mice. Our findings provide preliminary evidence for the RGC protective and microglia-associated neuroinflammatory reduction effects of ADSC-EVs by inhibiting the TLR4/MAPK/NF-κB proinflammatory cascade response in OHT mice, indicating the therapeutic potential ADSC-EVs or adjunctive therapy for glaucoma.
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Affiliation(s)
- Shangli Ji
- Aier Eye Hospital, Jinan University, 510632, Guangzhou, Guangdong, China
- Guangzhou Aier Eye Hospital, 510010, Guangzhou, Guangdong, China
| | - Yanfang Peng
- Aier Eye Institute, 410015, Changsha, Hunan, China
| | - Jian Liu
- Department of Ophthalmology, The Second Xiangya Hospital, Central South University, 410011, Changsha, Hunan, China
| | - Pang Xu
- Aier Eye Hospital, Jinan University, 510632, Guangzhou, Guangdong, China
| | - Shibo Tang
- Aier Eye Hospital, Jinan University, 510632, Guangzhou, Guangdong, China.
- Guangzhou Aier Eye Hospital, 510010, Guangzhou, Guangdong, China.
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11
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Pitha I, Du L, Nguyen TD, Quigley H. IOP and glaucoma damage: The essential role of optic nerve head and retinal mechanosensors. Prog Retin Eye Res 2024; 99:101232. [PMID: 38110030 PMCID: PMC10960268 DOI: 10.1016/j.preteyeres.2023.101232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 12/10/2023] [Accepted: 12/11/2023] [Indexed: 12/20/2023]
Abstract
There are many unanswered questions on the relation of intraocular pressure to glaucoma development and progression. IOP itself cannot be distilled to a single, unifying value, because IOP level varies over time, differs depending on ocular location, and can be affected by method of measurement. Ultimately, IOP level creates mechanical strain that affects axonal function at the optic nerve head which causes local extracellular matrix remodeling and retinal ganglion cell death - hallmarks of glaucoma and the cause of glaucomatous vision loss. Extracellular tissue strain at the ONH and lamina cribrosa is regionally variable and differs in magnitude and location between healthy and glaucomatous eyes. The ultimate targets of IOP-induced tissue strain in glaucoma are retinal ganglion cell axons at the optic nerve head and the cells that support axonal function (astrocytes, the neurovascular unit, microglia, and fibroblasts). These cells sense tissue strain through a series of signals that originate at the cell membrane and alter cytoskeletal organization, migration, differentiation, gene transcription, and proliferation. The proteins that translate mechanical stimuli into molecular signals act as band-pass filters - sensing some stimuli while ignoring others - and cellular responses to stimuli can differ based on cell type and differentiation state. Therefore, to fully understand the IOP signals that are relevant to glaucoma, it is necessary to understand the ultimate cellular targets of IOP-induced mechanical stimuli and their ability to sense, ignore, and translate these signals into cellular actions.
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Affiliation(s)
- Ian Pitha
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; Center for Nanomedicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; Glaucoma Center of Excellence, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Liya Du
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Thao D Nguyen
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Mechanical Engineering, The Johns Hopkins University, Baltimore, MD, USA
| | - Harry Quigley
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; Glaucoma Center of Excellence, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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Grannonico M, Miller DA, Liu M, Krause MA, Savier E, Erisir A, Netland PA, Cang J, Zhang HF, Liu X. Comparative In Vivo Imaging of Retinal Structures in Tree Shrews, Humans, and Mice. eNeuro 2024; 11:ENEURO.0373-23.2024. [PMID: 38538082 PMCID: PMC10972737 DOI: 10.1523/eneuro.0373-23.2024] [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: 09/17/2023] [Revised: 02/29/2024] [Accepted: 03/07/2024] [Indexed: 04/01/2024] Open
Abstract
Rodent models, such as mice and rats, are commonly used to examine retinal ganglion cell damage in eye diseases. However, as nocturnal animals, rodent retinal structures differ from primates, imposing significant limitations in studying retinal pathology. Tree shrews (Tupaia belangeri) are small, diurnal paraprimates that exhibit superior visual acuity and color vision compared with mice. Like humans, tree shrews have a dense retinal nerve fiber layer (RNFL) and a thick ganglion cell layer (GCL), making them a valuable model for investigating optic neuropathies. In this study, we applied high-resolution visible-light optical coherence tomography to characterize the tree shrew retinal structure in vivo and compare it with that of humans and mice. We quantitatively characterize the tree shrew's retinal layer structure in vivo, specifically examining the sublayer structures within the inner plexiform layer (IPL) for the first time. Next, we conducted a comparative analysis of retinal layer structures among tree shrews, mice, and humans. We then validated our in vivo findings in the tree shrew inner retina using ex vivo confocal microscopy. The in vivo and ex vivo analyses of the shrew retina build the foundation for future work to accurately track and quantify the retinal structural changes in the IPL, GCL, and RNFL during the development and progression of human optic diseases.
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Affiliation(s)
- Marta Grannonico
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904
| | - David A Miller
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208
| | - Mingna Liu
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904
| | - Michael A Krause
- Departments of Ophthalmology, University of Virginia, Charlottesville, Virginia 22904
| | - Elise Savier
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904
| | - Alev Erisir
- Psychology, University of Virginia, Charlottesville, Virginia 22904
- Program in Fundamental Neuroscience, University of Virginia, Charlottesville, Virginia 22904
| | - Peter A Netland
- Departments of Ophthalmology, University of Virginia, Charlottesville, Virginia 22904
| | - Jianhua Cang
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904
- Psychology, University of Virginia, Charlottesville, Virginia 22904
- Program in Fundamental Neuroscience, University of Virginia, Charlottesville, Virginia 22904
| | - Hao F Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208
| | - Xiaorong Liu
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904
- Psychology, University of Virginia, Charlottesville, Virginia 22904
- Program in Fundamental Neuroscience, University of Virginia, Charlottesville, Virginia 22904
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13
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Di Pierdomenico J, Gallego-Ortega A, Norte-Muñoz M, Vidal-Villegas B, Bravo I, Boluda-Ruiz M, Bernal-Garro JM, Fernandez-Bueno I, Pastor-Jimeno JC, Villegas-Pérez MP, Avilés-Trigueros M, de Los Ríos C, Vidal-Sanz M. Evaluation of the neuroprotective efficacy of the gramine derivative ITH12657 against NMDA-induced excitotoxicity in the rat retina. Front Neuroanat 2024; 18:1335176. [PMID: 38415017 PMCID: PMC10898249 DOI: 10.3389/fnana.2024.1335176] [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: 11/08/2023] [Accepted: 01/16/2024] [Indexed: 02/29/2024] Open
Abstract
Purpose The aim of this study was to investigate, the neuroprotective effects of a new Gramine derivative named: ITH12657, in a model of retinal excitotoxicity induced by intravitreal injection of NMDA. Methods Adult Sprague Dawley rats received an intravitreal injection of 100 mM NMDA in their left eye and were treated daily with subcutaneous injections of ITH12657 or vehicle. The best dose-response, therapeutic window study, and optimal treatment duration of ITH12657 were studied. Based on the best survival of Brn3a + RGCs obtained from the above-mentioned studies, the protective effects of ITH12657 were studied in vivo (retinal thickness and full-field Electroretinography), and ex vivo by quantifying the surviving population of Brn3a + RGCs, αRGCs and their subtypes α-ONsRGCs, α-ONtRGCs, and α-OFFRGCs. Results Administration of 10 mg/kg ITH12657, starting 12 h before NMDA injection and dispensed for 3 days, resulted in the best significant protection of Brn3a + RGCs against NMDA-induced excitotoxicity. In vivo, ITH12657-treated rats showed significant preservation of retinal thickness and functional protection against NMDA-induced retinal excitotoxicity. Ex vivo results showed that ITH12657 afforded a significant protection against NMDA-induced excitotoxicity for the populations of Brn3a + RGC, αRGC, and αONs-RGC, but not for the population of αOFF-RGC, while the population of α-ONtRGC was fully resistant to NMDA-induced excitotoxicity. Conclusion Subcutaneous administration of ITH12657 at 10 mg/kg, initiated 12 h before NMDA-induced retinal injury and continued for 3 days, resulted in the best protection of Brn3a + RGCs, αRGC, and αONs-RGC against excitotoxicity-induced RGC death. The population of αOFF-RGCs was extremely sensitive while α-ONtRGCs were fully resistant to NMDA-induced excitotoxicity.
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Affiliation(s)
| | | | - María Norte-Muñoz
- Departamento de Oftalmología, Universidad de Murcia e IMIB-Arrixaca, Murcia, Spain
| | | | - Isaac Bravo
- Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa, Madrid, Spain
- Departamento de Ciencias Básicas de la Salud, Universidad Rey Juan Carlos, Alcorcón, Spain
| | - María Boluda-Ruiz
- Departamento de Oftalmología, Universidad de Murcia e IMIB-Arrixaca, Murcia, Spain
| | | | - Iván Fernandez-Bueno
- Instituto Universitario de Oftalmobiología Aplicada (IOBA), Retina Group, Universidad de Valladolid, Valladolid, Spain
| | - Jose Carlos Pastor-Jimeno
- Instituto Universitario de Oftalmobiología Aplicada (IOBA), Retina Group, Universidad de Valladolid, Valladolid, Spain
| | | | | | - Cristobal de Los Ríos
- Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa, Madrid, Spain
- Departamento de Ciencias Básicas de la Salud, Universidad Rey Juan Carlos, Alcorcón, Spain
| | - Manuel Vidal-Sanz
- Departamento de Oftalmología, Universidad de Murcia e IMIB-Arrixaca, Murcia, Spain
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14
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Shinozaki Y, Namekata K, Guo X, Harada T. Glial cells as a promising therapeutic target of glaucoma: beyond the IOP. FRONTIERS IN OPHTHALMOLOGY 2024; 3:1310226. [PMID: 38983026 PMCID: PMC11182302 DOI: 10.3389/fopht.2023.1310226] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 12/18/2023] [Indexed: 07/11/2024]
Abstract
Glial cells, a type of non-neuronal cell found in the central nervous system (CNS), play a critical role in maintaining homeostasis and regulating CNS functions. Recent advancements in technology have paved the way for new therapeutic strategies in the fight against glaucoma. While intraocular pressure (IOP) is the most well-known modifiable risk factor, a significant number of glaucoma patients have normal IOP levels. Because glaucoma is a complex, multifactorial disease influenced by various factors that contribute to its onset and progression, it is imperative that we consider factors beyond IOP to effectively prevent or slow down the disease's advancement. In the realm of CNS neurodegenerative diseases, glial cells have emerged as key players due to their pivotal roles in initiating and hastening disease progression. The inhibition of dysregulated glial function holds the potential to protect neurons and restore brain function. Consequently, glial cells represent an enticing therapeutic candidate for glaucoma, even though the majority of glaucoma research has historically concentrated solely on retinal ganglion cells (RGCs). In addition to the neuroprotection of RGCs, the proper regulation of glial cell function can also facilitate structural and functional recovery in the retina. In this review, we offer an overview of recent advancements in understanding the non-cell-autonomous mechanisms underlying the pathogenesis of glaucoma. Furthermore, state-of-the-art technologies have opened up possibilities for regenerating the optic nerve, which was previously believed to be incapable of regeneration. We will also delve into the potential roles of glial cells in the regeneration of the optic nerve and the restoration of visual function.
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Affiliation(s)
- Youichi Shinozaki
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Kazuhiko Namekata
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Xiaoli Guo
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Takayuki Harada
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
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15
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Zueva MV, Neroeva NV, Zhuravleva AN, Bogolepova AN, Kotelin VV, Fadeev DV, Tsapenko IV. Fractal Phototherapy in Maximizing Retina and Brain Plasticity. ADVANCES IN NEUROBIOLOGY 2024; 36:585-637. [PMID: 38468055 DOI: 10.1007/978-3-031-47606-8_31] [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: 03/13/2024]
Abstract
The neuroplasticity potential is reduced with aging and impairs during neurodegenerative diseases and brain and visual system injuries. This limits the brain's capacity to repair the structure and dynamics of its activity after lesions. Maximization of neuroplasticity is necessary to provide the maximal CNS response to therapeutic intervention and adaptive reorganization of neuronal networks in patients with degenerative pathology and traumatic injury to restore the functional activity of the brain and retina.Considering the fractal geometry and dynamics of the healthy brain and the loss of fractality in neurodegenerative pathology, we suggest that the application of self-similar visual signals with a fractal temporal structure in the stimulation therapy can reactivate the adaptive neuroplasticity and enhance the effectiveness of neurorehabilitation. This proposition was tested in the recent studies. Patients with glaucoma had a statistically significant positive effect of fractal photic therapy on light sensitivity and the perimetric MD index, which shows that methods of fractal stimulation can be a novel nonpharmacological approach to neuroprotective therapy and neurorehabilitation. In healthy rabbits, it was demonstrated that a long-term course of photostimulation with fractal signals does not harm the electroretinogram (ERG) and retina structure. Rabbits with modeled retinal atrophy showed better dynamics of the ERG restoration during daily stimulation therapy for a week in comparison with the controls. Positive changes in the retinal function can indirectly suggest the activation of its adaptive plasticity and the high potential of stimulation therapy with fractal visual stimuli in a nonpharmacological neurorehabilitation, which requires further study.
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Affiliation(s)
- Marina V Zueva
- Department of Clinical Physiology of Vision, Helmholtz National Medical Research Center of Eye Diseases, Moscow, Russia
| | - Natalia V Neroeva
- Department of Pathology of the Retina and Optic Nerve, Helmholtz National Medical Research Center of Eye Diseases, Moscow, Russia
| | - Anastasia N Zhuravleva
- Department of Glaucoma, Helmholtz National Medical Research Center of Eye Diseases, Moscow, Russia
| | - Anna N Bogolepova
- Department of neurology, neurosurgery and medical genetics, Pirogov Russian National Research Medical University, Moscow, Russia
| | - Vladislav V Kotelin
- Department of Clinical Physiology of Vision, Helmholtz National Medical Research Center of Eye Diseases, Moscow, Russia
| | - Denis V Fadeev
- Scientific Experimental Center Department, Helmholtz National Medical Research Center of Eye Diseases, Moscow, Russia
| | - Irina V Tsapenko
- Department of Clinical Physiology of Vision, Helmholtz National Medical Research Center of Eye Diseases, Moscow, Russia
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16
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Fahrenthold BK, Cavanaugh MR, Tamhankar M, Lam BL, Feldon SE, Johnson BA, Huxlin KR. Training in cortically-blind fields confers patient-specific benefit against retinal thinning after occipital stroke. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.12.19.23298260. [PMID: 38196617 PMCID: PMC10775322 DOI: 10.1101/2023.12.19.23298260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
Purpose Damage to the adult primary visual cortex (V1) causes vision loss in the contralateral hemifield, initiating a process of trans-synaptic retrograde degeneration (TRD). Here, we examined retinal correlates of TRD using a new metric to account for global changes in inner retinal thickness, and asked if perceptual training in the intact or blind field impacts its progression. Methods We performed a meta-analysis of optical coherence tomography (OCT) data in 48 participants with unilateral V1 stroke and homonymous visual defects, who completed clinical trial NCT03350919. After measuring the thickness of the macular ganglion cell and inner plexiform layers (GCL-IPL), and the peripapillary retinal nerve fiber layer (RNFL), we computed individual laterality indices (LI) at baseline and after ~6 months of daily motion discrimination training in the intact- or blind-field. Increasingly positive LI denoted greater layer thinning in retinal regions affected versus unaffected by the cortical damage. Results Pre-training, the affected GCL-IPL and RNFL were thinner than their unaffected counterparts, generating LI values positively correlated with time since stroke. Participants trained in their intact-field exhibited increased LIGCL-IPL. Those trained in their blind-field had no significant change in LIGCL-IPL. LIRNFL did not change in either group. Conclusions Relative shrinkage of the affected versus unaffected macular GCL-IPL can be reliably measured at an individual level and increases with time post-V1 stroke. Relative thinning progressed during intact-field training, but appeared to be halted by training within the blind field, suggesting a potentially neuroprotective effect of this simple behavioral intervention.
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Affiliation(s)
- Berkeley K. Fahrenthold
- Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, NY, USA
| | - Matthew R. Cavanaugh
- Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, NY, USA
| | - Madhura Tamhankar
- Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, USA
| | - Byron L. Lam
- Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA
| | - Steven E. Feldon
- Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, NY, USA
| | - Brent A. Johnson
- Department of Biostatistics and Computational Biology, University of Rochester, Rochester, NY, USA
| | - Krystel R. Huxlin
- Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, NY, USA
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17
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Zuo Z, Zhang Z, Zhang S, Fan B, Li G. The Molecular Mechanisms Involved in Axonal Degeneration and Retrograde Retinal Ganglion Cell Death. DNA Cell Biol 2023; 42:653-667. [PMID: 37819746 DOI: 10.1089/dna.2023.0180] [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] [Indexed: 10/13/2023] Open
Abstract
Axonal degeneration is a pathologic change common to multiple retinopathies and optic neuropathies. Various pathologic factors, such as mechanical injury, inflammation, and ischemia, can damage retinal ganglion cell (RGC) somas and axons, eventually triggering axonal degeneration and RGC death. The molecular mechanisms of somal and axonal degeneration are distinct but also overlap, and axonal degeneration can result in retrograde somal degeneration. While the mitogen-activated protein kinase pathway acts as a central node in RGC axon degeneration, several newly discovered molecules, such as sterile alpha and Toll/interleukin-1 receptor motif-containing protein 1 and nicotinamide mononucleotide adenylyltransferase 2, also play a critical role in this pathological process following different types of injury. Therefore, we summarize the types of injury that cause RGC axon degeneration and retrograde RGC death and important underlying molecular mechanisms, providing a reference for the identification of targets for protecting axons and RGCs.
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Affiliation(s)
- Zhaoyang Zuo
- Department of Ophthalmology, Second Hospital of Jilin University, Changchun, China
| | - Ziyuan Zhang
- Department of Ophthalmology, Second Hospital of Jilin University, Changchun, China
| | - Siming Zhang
- Department of Ophthalmology, Second Hospital of Jilin University, Changchun, China
| | - Bin Fan
- Department of Ophthalmology, Second Hospital of Jilin University, Changchun, China
| | - Guangyu Li
- Department of Ophthalmology, Second Hospital of Jilin University, Changchun, China
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18
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Choe S, Jang M, Kim YK, Park KH, Jeoung JW. Clinical usefulness of layer-by-layer deviation maps of Spectralis OCT: comparison with Cirrus OCT. Br J Ophthalmol 2023; 107:1645-1651. [PMID: 36002236 DOI: 10.1136/bjo-2022-321054] [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: 01/04/2022] [Accepted: 07/31/2022] [Indexed: 11/03/2022]
Abstract
BACKGROUND/AIMS To compare the diagnostic abilities of Spectralis (Heidelberg Engineering, Heidelberg, Germany) and Cirrus (Carl Zeiss Meditec, Dublin, California, USA) spectral domain-optical coherence tomography (OCT) for retinal nerve fibre layer (RNFL) defect detection among patients with preperimetric glaucoma (PPG) and early glaucoma (EG). METHODS In this cross-sectional study, a total of 144 eyes (47 healthy, 43 PPG, 54 EG; MD≥-6 dB) of 144 participants underwent Spectralis and Cirrus OCT on the same day. The presence of RNFL defect on red-free RNFL photography and the respective deviation maps of Spectralis and Cirrus OCT was rated. Areas under the receiver operating characteristic curves (AUCs), sensitivities and specificities were analysed for each deviation layer to discriminate healthy eyes from PPG and EG eyes. RESULTS The RNFL, ganglion cell layer (GCL) and retinal layers of Spectralis OCT and the RNFL and macular ganglion cell-inner plexiform layer of Cirrus OCT showed high diagnostic performance (all AUCs >0.8) in discriminating PPG and EG eyes from healthy eyes. Among them, RNFL layer of Cirrus OCT had the largest AUC (0.840 for PPG, 0.959 for EG) but showed no statistical differences from RNFL and retinal layers of Spectralis OCT. The inner plexiform layer (IPL) of Spectralis OCT had the smallest AUC (0.563 for PPG, 0.799 for EG). CONCLUSIONS The Spectralis and Cirrus OCT deviation maps showed good diagnostic abilities except for the IPL layer of Spectralis. In the clinical setting, both Spectralis and Cirrus OCT can be useful for detection of RNFL defects in PPG and EG eyes.
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Affiliation(s)
- Sooyeon Choe
- Department of Ophthalmology, Seoul National University Hospital, Seoul, South Korea
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, South Korea
| | - Mirinae Jang
- Department of Ophthalmology, Seoul National University Hospital, Seoul, South Korea
| | - Young Kook Kim
- Department of Ophthalmology, Seoul National University Hospital, Seoul, South Korea
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, South Korea
| | - Ki Ho Park
- Department of Ophthalmology, Seoul National University Hospital, Seoul, South Korea
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, South Korea
| | - Jin Wook Jeoung
- Department of Ophthalmology, Seoul National University Hospital, Seoul, South Korea
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, South Korea
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19
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Boccuni I, Bas-Orth C, Bruehl C, Draguhn A, Fairless R. Glutamate transporter contribution to retinal ganglion cell vulnerability in a rat model of multiple sclerosis. Neurobiol Dis 2023; 187:106306. [PMID: 37734623 DOI: 10.1016/j.nbd.2023.106306] [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: 05/19/2023] [Revised: 09/05/2023] [Accepted: 09/18/2023] [Indexed: 09/23/2023] Open
Abstract
Glial glutamate transporters actively participate in neurotransmission and have a fundamental role in determining the ambient glutamate concentration in the extracellular space. Their expression is dynamically regulated in many diseases, including experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis. In EAE, a downregulation has been reported which may render neurons more susceptible to glutamate excitotoxicity. In this study, we have investigated the expression of GLAST (EAAT1) and GLT-1 (EAAT2) in the retina of Brown Norway rats following induction of myelin oligodendrocyte glycoprotein (MOG)-EAE, which results in retinal ganglion cell (RGC) degeneration and dysfunction. In addition, we tested whether AAV-mediated overexpression of GLAST in the retina can protect RGCs from degeneration. To address the impact of glutamate transporter modulation on RGCs, we performed whole-cell recordings and measured tonic NMDA receptor-mediated currents in the absence and presence of a glutamate-uptake blocker. We report that αOFF-RGCs show larger tonic glutamate-induced currents than αON-RGCs, in line with their greater vulnerability under neuroinflammatory conditions. We further show that increased AAV-mediated expression of GLAST in the retina does indeed protect RGCs from degeneration during the inflammatory disease. Collectively, our study highlights the neuroprotective role of glutamate transporters in the EAE retina and provides a characterization of tonic glutamate-currents of αRGCs. The larger effects of increased extracellular glutamate concentration on the αOFF-subtype may underlie its enhanced vulnerability to degeneration.
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Affiliation(s)
- Isabella Boccuni
- Institute of Physiology and Pathophysiology, University of Heidelberg, Heidelberg 69120, Germany
| | - Carlos Bas-Orth
- Institute of Anatomy and Cell Biology, University of Heidelberg, Heidelberg 69120, Germany
| | - Claus Bruehl
- Institute of Physiology and Pathophysiology, University of Heidelberg, Heidelberg 69120, Germany
| | - Andreas Draguhn
- Institute of Physiology and Pathophysiology, University of Heidelberg, Heidelberg 69120, Germany
| | - Richard Fairless
- Department of Neurology, University Clinic Heidelberg, Heidelberg 69120, Germany; Clinical Cooperation Unit (CCU) Neurooncology, German Cancer Consortium (DKTK), German Cancer Research Center (DFKZ), Heidelberg 69120, Germany.
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20
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Zhao M, Toma K, Kinde B, Li L, Patel AK, Wu KY, Lum MR, Tan C, Hooper JE, Kriegstein AR, La Torre A, Liao YJ, Welsbie DS, Hu Y, Han Y, Duan X. Osteopontin drives retinal ganglion cell resiliency in glaucomatous optic neuropathy. Cell Rep 2023; 42:113038. [PMID: 37624696 PMCID: PMC10591811 DOI: 10.1016/j.celrep.2023.113038] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 06/28/2023] [Accepted: 08/11/2023] [Indexed: 08/27/2023] Open
Abstract
Chronic neurodegeneration and acute injuries lead to neuron losses via diverse processes. We compared retinal ganglion cell (RGC) responses between chronic glaucomatous conditions and the acute injury model. Among major RGC subclasses, αRGCs and intrinsically photosensitive RGCs (ipRGCs) preferentially survive glaucomatous conditions, similar to findings in the retina subject to axotomy. Focusing on an αRGC intrinsic factor, Osteopontin (secreted phosphoprotein 1 [Spp1]), we found an ectopic neuronal expression of Osteopontin (Spp1) in other RGCs subject to glaucomatous conditions. This contrasted with the Spp1 downregulation subject to axotomy. αRGC-specific Spp1 elimination led to significant αRGC loss, diminishing their resiliency. Spp1 overexpression led to robust neuroprotection of susceptible RGC subclasses under glaucomatous conditions. In contrast, Spp1 overexpression did not significantly protect RGCs subject to axotomy. Additionally, SPP1 marked adult human RGC subsets with large somata and SPP1 expression in the aqueous humor correlated with glaucoma severity. Our study reveals Spp1's role in mediating neuronal resiliency in glaucoma.
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Affiliation(s)
- Mengya Zhao
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA 94158, USA
| | - Kenichi Toma
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA 94158, USA
| | - Benyam Kinde
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA 94158, USA.
| | - Liang Li
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Amit K Patel
- Viterbi Family Department of Ophthalmology, University of California San Diego, San Diego, CA 92037, USA
| | - Kong-Yan Wu
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA 94158, USA
| | - Matthew R Lum
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA 94158, USA
| | - Chengxi Tan
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA 94158, USA
| | - Jody E Hooper
- Department of Pathology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Arnold R Kriegstein
- Department of Neurology and The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California San Francisco, San Francisco, CA 94143, USA
| | - Anna La Torre
- Department of Cell Biology and Human Anatomy, University of California, Davis, Davis, CA 95616, USA
| | - Yaping Joyce Liao
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Derek S Welsbie
- Viterbi Family Department of Ophthalmology, University of California San Diego, San Diego, CA 92037, USA
| | - Yang Hu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA.
| | - Ying Han
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA 94158, USA.
| | - Xin Duan
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA 94158, USA.
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21
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Maes ME, Donahue RJ, Schlamp CL, Marola OJ, Libby RT, Nickells RW. BAX activation in mouse retinal ganglion cells occurs in two temporally and mechanistically distinct steps. Mol Neurodegener 2023; 18:67. [PMID: 37752598 PMCID: PMC10521527 DOI: 10.1186/s13024-023-00659-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 09/15/2023] [Indexed: 09/28/2023] Open
Abstract
BACKGROUND Pro-apoptotic BAX is a central mediator of retinal ganglion cell (RGC) death after optic nerve damage. BAX activation occurs in two stages including translocation of latent BAX to the mitochondrial outer membrane (MOM) and then permeabilization of the MOM to facilitate the release of apoptotic signaling molecules. As a critical component of RGC death, BAX is an attractive target for neuroprotective therapies and an understanding of the kinetics of BAX activation and the mechanisms controlling the two stages of this process in RGCs is potentially valuable in informing the development of a neuroprotective strategy. METHODS The kinetics of BAX translocation were assessed by both static and live-cell imaging of a GFP-BAX fusion protein introduced into RGCs using AAV2-mediated gene transfer in mice. Activation of BAX was achieved using an acute optic nerve crush (ONC) protocol. Live-cell imaging of GFP-BAX was achieved using explants of mouse retina harvested 7 days after ONC. Kinetics of translocation in RGCs were compared to GFP-BAX translocation in 661W tissue culture cells. Permeabilization of GFP-BAX was assessed by staining with the 6A7 monoclonal antibody, which recognizes a conformational change in this protein after MOM insertion. Assessment of individual kinases associated with both stages of activation was made using small molecule inhibitors injected into the vitreous either independently or in concert with ONC surgery. The contribution of the Dual Leucine Zipper-JUN-N-Terminal Kinase cascade was evaluated using mice with a double conditional knock-out of both Mkk4 and Mkk7. RESULTS ONC induces the translocation of GFP-BAX in RGCs at a slower rate and with less intracellular synchronicity than 661W cells, but exhibits less variability among mitochondrial foci within a single cell. GFP-BAX was also found to translocate in all compartments of an RGC including the dendritic arbor and axon. Approximately 6% of translocating RGCs exhibited retrotranslocation of BAX immediately following translocation. Unlike tissue culture cells, which exhibit simultaneous translocation and permeabilization, RGCs exhibited a significant delay between these two stages, similar to detached cells undergoing anoikis. Translocation, with minimal permeabilization could be induced in a subset of RGCs using an inhibitor of Focal Adhesion Kinase (PF573228). Permeabilization after ONC, in a majority of RGCs, could be inhibited with a broad spectrum kinase inhibitor (sunitinib) or a selective inhibitor for p38/MAPK14 (SB203580). Intervention of DLK-JNK axis signaling abrogated GFP-BAX translocation after ONC. CONCLUSIONS A comparison between BAX activation kinetics in tissue culture cells and in cells of a complex tissue environment shows distinct differences indicating that caution should be used when translating findings from one condition to the other. RGCs exhibit both a delay between translocation and permeabilization and the ability for translocated BAX to be retrotranslocated, suggesting several stages at which intervention of the activation process could be exploited in the design of a therapeutic strategy.
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Affiliation(s)
- Margaret E Maes
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, 1300 University Avenue, Madison, WI, 53706, USA
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Ryan J Donahue
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, 1300 University Avenue, Madison, WI, 53706, USA
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, USA
| | - Cassandra L Schlamp
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, 1300 University Avenue, Madison, WI, 53706, USA
| | - Olivia J Marola
- Department of Ophthalmology, University of Rochester Medical Center, Rochester, NY, USA
| | - Richard T Libby
- Department of Ophthalmology, University of Rochester Medical Center, Rochester, NY, USA
| | - Robert W Nickells
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, 1300 University Avenue, Madison, WI, 53706, USA.
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, USA.
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22
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Soucy JR, Aguzzi EA, Cho J, Gilhooley MJ, Keuthan C, Luo Z, Monavarfeshani A, Saleem MA, Wang XW, Wohlschlegel J, Baranov P, Di Polo A, Fortune B, Gokoffski KK, Goldberg JL, Guido W, Kolodkin AL, Mason CA, Ou Y, Reh TA, Ross AG, Samuels BC, Welsbie D, Zack DJ, Johnson TV. Retinal ganglion cell repopulation for vision restoration in optic neuropathy: a roadmap from the RReSTORe Consortium. Mol Neurodegener 2023; 18:64. [PMID: 37735444 PMCID: PMC10514988 DOI: 10.1186/s13024-023-00655-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 09/07/2023] [Indexed: 09/23/2023] Open
Abstract
Retinal ganglion cell (RGC) death in glaucoma and other optic neuropathies results in irreversible vision loss due to the mammalian central nervous system's limited regenerative capacity. RGC repopulation is a promising therapeutic approach to reverse vision loss from optic neuropathies if the newly introduced neurons can reestablish functional retinal and thalamic circuits. In theory, RGCs might be repopulated through the transplantation of stem cell-derived neurons or via the induction of endogenous transdifferentiation. The RGC Repopulation, Stem Cell Transplantation, and Optic Nerve Regeneration (RReSTORe) Consortium was established to address the challenges associated with the therapeutic repair of the visual pathway in optic neuropathy. In 2022, the RReSTORe Consortium initiated ongoing international collaborative discussions to advance the RGC repopulation field and has identified five critical areas of focus: (1) RGC development and differentiation, (2) Transplantation methods and models, (3) RGC survival, maturation, and host interactions, (4) Inner retinal wiring, and (5) Eye-to-brain connectivity. Here, we discuss the most pertinent questions and challenges that exist on the path to clinical translation and suggest experimental directions to propel this work going forward. Using these five subtopic discussion groups (SDGs) as a framework, we suggest multidisciplinary approaches to restore the diseased visual pathway by leveraging groundbreaking insights from developmental neuroscience, stem cell biology, molecular biology, optical imaging, animal models of optic neuropathy, immunology & immunotolerance, neuropathology & neuroprotection, materials science & biomedical engineering, and regenerative neuroscience. While significant hurdles remain, the RReSTORe Consortium's efforts provide a comprehensive roadmap for advancing the RGC repopulation field and hold potential for transformative progress in restoring vision in patients suffering from optic neuropathies.
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Affiliation(s)
- Jonathan R Soucy
- Department of Ophthalmology, Schepens Eye Research Institute of Mass. Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Erika A Aguzzi
- The Institute of Ophthalmology, University College London, London, England, UK
| | - Julie Cho
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Michael James Gilhooley
- The Institute of Ophthalmology, University College London, London, England, UK
- Moorfields Eye Hospital, London, England, UK
| | - Casey Keuthan
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ziming Luo
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Aboozar Monavarfeshani
- Center for Brain Science and Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
- Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA
| | - Meher A Saleem
- Bascom Palmer Eye Institute, University of Miami Health System, Miami, FL, USA
| | - Xue-Wei Wang
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | - Petr Baranov
- Department of Ophthalmology, Schepens Eye Research Institute of Mass. Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Adriana Di Polo
- Department of Neuroscience, University of Montreal, Montreal, QC, Canada
- University of Montreal Hospital Research Centre, Montreal, QC, Canada
| | - Brad Fortune
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Health, Portland, OR, USA
| | - Kimberly K Gokoffski
- Department of Ophthalmology, Roski Eye Institute, University of Southern California, Los Angeles, CA, USA
| | - Jeffrey L Goldberg
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - William Guido
- Department of Anatomical Sciences and Neurobiology, School of Medicine, University of Louisville, Louisville, KY, USA
| | - Alex L Kolodkin
- The Solomon H Snyder, Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Carol A Mason
- Departments of Pathology and Cell Biology, Neuroscience, and Ophthalmology, College of Physicians and Surgeons, Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Yvonne Ou
- Department of Ophthalmology, University of California, San Francisco, CA, USA
| | - Thomas A Reh
- Department of Biological Structure, University of Washington, Seattle, WA, USA
| | - Ahmara G Ross
- Departments of Ophthalmology and Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Brian C Samuels
- Department of Ophthalmology and Visual Sciences, Callahan Eye Hospital, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Derek Welsbie
- Shiley Eye Institute and Viterbi Family Department of Ophthalmology, University of California, San Diego, CA, USA
| | - Donald J Zack
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, 21287 MD, USA
- Departments of Neuroscience, Molecular Biology & Genetics, and Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Thomas V Johnson
- Departments of Neuroscience, Molecular Biology & Genetics, and Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Cellular & Molecular Medicine Program, Johns Hopkins University School of Medicine, Baltimore, 21287 MD, USA.
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23
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Shang X, Reche J, Lincke JB, Häner NU, Lever M, Böhm MR, Bormann C, Zinkernagel MS, Unterlauft JD. Stage specific glaucomatous changes of the macula recorded using spectral domain optical coherence tomography. Photodiagnosis Photodyn Ther 2023; 43:103673. [PMID: 37380114 DOI: 10.1016/j.pdpdt.2023.103673] [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: 04/03/2023] [Revised: 05/18/2023] [Accepted: 06/22/2023] [Indexed: 06/30/2023]
Abstract
BACKGROUND This study aimed to compare the thickness of different macular retinal layers in glaucomatous eyes and healthy controls, and evaluate the diagnostic performance of spectral domain optical coherence tomography (SD-OCT) parameters. METHODS In this cross-sectional comparative study, 48 glaucomatous eyes and 44 healthy controls were included. The thickness of the total retina and all retinal layers were obtained using the Early Treatment Diagnostic Retinopathy Study (ETDRS) grid. The minimal and average values of outer and inner ETDRS-rings were calculated. The diagnostic performance for detection of glaucoma was evaluated using the area under the receiver operating characteristic curve (AUC). RESULTS The thickness of the total retina, ganglion cell layer (GCL), and inner-plexiform layer (IPL) was significantly thinner in glaucomatous eyes in all sectors except the center (all p<0.05). The thickness of retinal nerve fiber layer (RNFL) was significantly thinner in the glaucoma group except in the center, nasal inner, and temporal outer sectors (all p<0.05). Layer thinning advanced with glaucoma severity. The minimal outer GCL thickness showed the highest AUC value for discrimination between glaucomatous eyes and healthy controls(0.955). The minimal outer IPL showed the highest AUC value for discriminating early-stage glaucomatous eyes from healthy controls (0.938). CONCLUSIONS Glaucomatous eyes were found to have significant thinning in the macular region. GCL and IPL showed high ability to discriminate glaucomatous and early-stage glaucomatous eyes from controls. Applying the minimal value to the ETDRS grid has the potential to provide good diagnostic abilities in glaucoma screening.
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Affiliation(s)
- Xiao Shang
- Department of Ophthalmology, Inselspital Bern University Hospital, University of Bern, Freiburgstrasse 15, Bern 3010, Switzerland
| | - Jelena Reche
- Department of Ophthalmology, Inselspital Bern University Hospital, University of Bern, Freiburgstrasse 15, Bern 3010, Switzerland
| | - Joel-Benjamin Lincke
- Department of Ophthalmology, Inselspital Bern University Hospital, University of Bern, Freiburgstrasse 15, Bern 3010, Switzerland
| | - Nathanael Urs Häner
- Department of Ophthalmology, Inselspital Bern University Hospital, University of Bern, Freiburgstrasse 15, Bern 3010, Switzerland
| | - Mael Lever
- University Eye Hospital Essen, Hufelandstrasse 55, Essen 45147, Germany
| | - Michael Rr Böhm
- University Eye Hospital Essen, Hufelandstrasse 55, Essen 45147, Germany
| | - Caroline Bormann
- University Eye Hospital Leipzig, University of Leipzig, Liebigstrasse 10, Leipzig 04105, Germany
| | - Martin S Zinkernagel
- Department of Ophthalmology, Inselspital Bern University Hospital, University of Bern, Freiburgstrasse 15, Bern 3010, Switzerland
| | - Jan Darius Unterlauft
- Department of Ophthalmology, Inselspital Bern University Hospital, University of Bern, Freiburgstrasse 15, Bern 3010, Switzerland.
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24
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Soliño M, Yu A, Della Santina L, Ou Y. Large-scale survey of excitatory synapses reveals sublamina-specific and asymmetric synapse disassembly in a neurodegenerative circuit. iScience 2023; 26:107262. [PMID: 37609630 PMCID: PMC10440711 DOI: 10.1016/j.isci.2023.107262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 05/09/2023] [Accepted: 06/27/2023] [Indexed: 08/24/2023] Open
Abstract
In the nervous system, parallel circuits are organized in part by the lamina-specific compartmentalization of synaptic connections. In sensory systems such as mammalian retina, degenerating third-order neurons remodel their local presynaptic connectivity with second-order neurons. To determine whether there are sublamina-specific perturbations after injury of adult retinal ganglion cells, we comprehensively analyzed excitatory synapses across the inner plexiform layer (IPL) where bipolar cells connect to ganglion cells. Here, we show that pre- and postsynaptic component loss occurs throughout the IPL in a sublamina-dependent fashion after transient intraocular pressure elevation. Partnered synaptic components are lost as neurodegeneration progresses, while unpartnered synaptic components remain stable. Furthermore, presynaptic components are either lost first or simultaneously with the postsynaptic component. Our results demonstrate that this degenerating neural circuit exhibits differential vulnerability of excitatory synapses depending on IPL depth, highlighting the ordered disassembly of synapses that is specific to laminar compartments of the retina.
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Affiliation(s)
- Manuel Soliño
- Department of Ophthalmology, University of California San Francisco School of Medicine, San Francisco, CA 94143, USA
| | - Alfred Yu
- Department of Ophthalmology, University of California San Francisco School of Medicine, San Francisco, CA 94143, USA
| | - Luca Della Santina
- Department of Ophthalmology, University of California San Francisco School of Medicine, San Francisco, CA 94143, USA
- College of Optometry, University of Houston, Houston, TX 77204, USA
| | - Yvonne Ou
- Department of Ophthalmology, University of California San Francisco School of Medicine, San Francisco, CA 94143, USA
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25
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Shiga Y, Nishida T, Jeoung JW, Di Polo A, Fortune B. Optical Coherence Tomography and Optical Coherence Tomography Angiography: Essential Tools for Detecting Glaucoma and Disease Progression. FRONTIERS IN OPHTHALMOLOGY 2023; 3:1217125. [PMID: 37982032 PMCID: PMC10655832 DOI: 10.3389/fopht.2023.1217125] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 07/03/2023] [Indexed: 11/21/2023]
Abstract
Early diagnosis and detection of disease progression are critical to successful therapeutic intervention in glaucoma, the leading cause of irreversible blindness worldwide. Optical coherence tomography (OCT) is a non-invasive imaging technique that allows objective quantification in vivo of key glaucomatous structural changes in the retina and the optic nerve head (ONH). Advances in OCT technology have increased the scan speed and enhanced image quality, contributing to early glaucoma diagnosis and monitoring, as well as the visualization of critically important structures deep within the ONH, such as the lamina cribrosa. OCT angiography (OCTA) is a dye-free technique for noninvasively assessing ocular microvasculature, including capillaries within each plexus serving the macula, peripapillary retina and ONH regions, as well as the deeper vessels of the choroid. This layer-specific assessment of the microvasculature has provided evidence that retinal and choroidal vascular impairments can occur during early stages of glaucoma, suggesting that OCTA-derived measurements could be used as biomarkers for enhancing detection of glaucoma and its progression, as well as to reveal novel insights about pathophysiology. Moreover, these innovations have demonstrated that damage to the macula, a critical region for the vision-related quality of life, can be observed in the early stages of glaucomatous eyes, leading to a paradigm shift in glaucoma monitoring. Other advances in software and hardware, such as artificial intelligence-based algorithms, adaptive optics, and visible-light OCT, may further benefit clinical management of glaucoma in the future. This article reviews the utility of OCT and OCTA for glaucoma diagnosis and disease progression detection, emphasizes the importance of detecting macula damage in glaucoma, and highlights the future perspective of OCT and OCTA. We conclude that the OCT and OCTA are essential glaucoma detection and monitoring tools, leading to clinical and economic benefits for patients and society.
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Affiliation(s)
- Yukihiro Shiga
- Neuroscience Division, Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec H2X 0A9, Canada
- Department of Neuroscience, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Takashi Nishida
- Hamilton Glaucoma Center, Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California, San Diego, La Jolla, California 92093, USA
| | - Jin Wook Jeoung
- Department of Ophthalmology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Adriana Di Polo
- Neuroscience Division, Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec H2X 0A9, Canada
- Department of Neuroscience, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Brad Fortune
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Health, 1225 NE Second Avenue, Portland, Oregon 97232, USA
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26
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Sharif NA. Identifying new drugs and targets to treat rapidly elevated intraocular pressure for angle closure and secondary glaucomas to curb visual impairment and prevent blindness. Exp Eye Res 2023; 232:109444. [PMID: 36958427 DOI: 10.1016/j.exer.2023.109444] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 02/23/2023] [Accepted: 03/16/2023] [Indexed: 03/25/2023]
Abstract
A multitude of pharmacological compounds have been shown to lower and control intraocular pressure (IOP) in numerous species of animals and human subjects after topical ocular dosing or via other routes of administration. Most researchers have been interested in finding drug candidates that exhibit a relatively long duration of action from a chronic therapeutic use perspective, for example to treat ocular hypertension (OHT), primary open-angle glaucoma and even normotensive glaucoma. However, it is equally important to seek and characterize treatment modalities which offer a rapid onset of action to help provide fast relief from quickly rising IOP that occurs in certain eye diseases. These include acute angle-closure glaucoma, primary angle-closure glaucoma, uveitic and inflammatory glaucoma, medication-induced OHT, and other secondary glaucomas induced by eye injury or infection which can cause partial or complete loss of eyesight. Such fast-acting agents can delay or prevent the need for ocular surgery which is often used to lower the dangerously raised IOP. This research survey was therefore directed at identifying agents from the literature that demonstrated ocular hypotensive activity, normalizing and unifying the data, determining their onset of action and rank ordering them on the basis of rapidity of action starting within 30-60 min and lasting up to at least 3-4 h post topical ocular dosing in different animal species. This research revealed a few health authority-approved drugs and some investigational compounds that appear to meet the necessary criteria of fast onset of action coupled with significant efficacy to reduce elevated IOP (by ≥ 20%, preferably by >30%). However, translation of the novel animal-based findings to the human conditions remains to be demonstrated but represent viable targets, especially EP2-receptor agonists (e.g. omidenepag isopropyl; AL-6598; butaprost), mixed activity serotonin/dopamine receptor agonists (e.g. cabergoline), rho kinase inhibitors (e.g. AMA0076, Y39983), CACNA2D1-gene product inhibitors (e.g. pregabalin), melatonin receptor agonists, and certain K+-channel openers (e.g. nicorandil, pinacidil). Other drug candidates and targets were also identified and will be discussed.
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Affiliation(s)
- Najam A Sharif
- Institute of Ophthalmology, University College London (UCL), London, UK; Imperial College of Science and Technology, St. Mary's Campus, London, UK; Eye-ACP Duke-National University of Singapore Medical School, Singapore; Singapore Eye Research Institute (SERI), Singapore; Department of Pharmacy Sciences, Creighton University, Omaha, NE, USA; Department of Pharmacology and Neuroscience, University of North Texas Health Sciences Center, Fort Worth, Texas, USA; Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Texas Southern University, Houston, Texas, USA; Ophthalmology Innovation Center, Santen Inc USA, Emeryville, CA, USA.
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27
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Kumar S, Akopian A, Bloomfield SA. Neuroprotection of Retinal Ganglion Cells Suppresses Microglia Activation in a Mouse Model of Glaucoma. Invest Ophthalmol Vis Sci 2023; 64:24. [PMID: 37318444 DOI: 10.1167/iovs.64.7.24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023] Open
Abstract
Purpose Microglial activation has been implicated in many neurodegenerative eye diseases, but the interrelationship between cell loss and microglia activation remains unclear. In glaucoma, there is no consensus yet whether microglial activation precedes or is a consequence of retinal ganglion cell (RGC) degeneration. We therefore investigated the temporal and spatial appearance of activated microglia in retina and their correspondence to RGC degeneration in glaucoma. Methods We used an established microbead occlusion model of glaucoma in mouse whereby intraocular pressure (IOP) was elevated. Specific antibodies were used to immunolabel microglia in resting and activated states. To block retinal gap junction (GJ) communication, which has been shown previously to provide significant neuroprotection of RGCs, the GJ blocker meclofenamic acid was administered or connexin36 (Cx36) GJ subunits were ablated genetically. We then studied microglial activation at different time points after microbead injection in control and neuroprotected retinas. Results Histochemical analysis of flatmount retinas revealed major changes in microglia morphology, density, and immunoreactivity in microbead-injected eyes. An early stage of microglial activation followed IOP elevation, as indicated by changes in morphology and cell density, but preceded RGC death. In contrast, the later stage of microglia activation, associated with upregulation of major histocompatibility complex class II expression, corresponded temporally to the initial loss of RGCs. However, we found that protection of RGCs afforded by GJ blockade or genetic ablation largely suppressed microglial changes at all stages of activation in glaucomatous retinas. Conclusions Together, our data strongly suggest that microglia activation in glaucoma is a consequence, rather than a cause, of initial RGC degeneration and death.
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Affiliation(s)
- Sandeep Kumar
- Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, New York, United States
| | - Abram Akopian
- Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, New York, United States
| | - Stewart A Bloomfield
- Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, New York, United States
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28
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Maes ME, Donahue RJ, Schlamp CL, Marola OJ, Libby RT, Nickells R. BAX activation in mouse retinal ganglion cells occurs in two temporally and mechanistically distinct steps. RESEARCH SQUARE 2023:rs.3.rs-2846437. [PMID: 37292963 PMCID: PMC10246290 DOI: 10.21203/rs.3.rs-2846437/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Background Pro-apoptotic BAX is a central mediator of retinal ganglion cell (RGC) death after optic nerve damage. BAX activation occurs in two stages including translocation of latent BAX to the mitochondrial outer membrane (MOM) and then permeabilization of the MOM to facilitate the release of apoptotic signaling molecules. As a critical component of RGC death, BAX is an attractive target for neuroprotective therapies and an understanding of the kinetics of BAX activation and the mechanisms controlling the two stages of this process in RGCs is potentially valuable in informing the development of a neuroprotective strategy. Methods The kinetics of BAX translocation were assessed by both static and live-cell imaging of a GFP-BAX fusion protein introduced into RGCs using AAV2-mediated gene transfer in mice. Activation of BAX was achieved using an acute optic nerve crush (ONC) protocol. Live-cell imaging of GFP-BAX was achieved using explants of mouse retina harvested 7 days after ONC. Kinetics of translocation in RGCs were compared to GFP-BAX translocation in 661W tissue culture cells. Permeabilization of GFP-BAX was assessed by staining with the 6A7 monoclonal antibody, which recognizes a conformational change in this protein after MOM insertion. Assessment of individual kinases associated with both stages of activation was made using small molecule inhibitors injected into the vitreous either independently or in concert with ONC surgery. The contribution of the Dual Leucine Zipper-JUN-N-Terminal Kinase cascade was evaluated using mice with a double conditional knock-out of both Mkk4 and Mkk7 . Results ONC induces the translocation of GFP-BAX in RGCs at a slower rate and with less intracellular synchronicity than 661W cells, but exhibits less variability among mitochondrial foci within a single cell. GFP-BAX was also found to translocate in all compartments of an RGC including the dendritic arbor and axon. Approximately 6% of translocating RGCs exhibited retrotranslocation of BAX immediately following translocation. Unlike tissue culture cells, which exhibit simultaneous translocation and permeabilization, RGCs exhibited a significant delay between these two stages, similar to detached cells undergoing anoikis. Translocation, with minimal permeabilization could be induced in a subset of RGCs using an inhibitor of Focal Adhesion Kinase (PF573228). Permeabilization after ONC, in a majority of RGCs, could be inhibited with a broad spectrum kinase inhibitor (sunitinib) or a selective inhibitor for p38/MAPK14 (SB203580). Intervention of DLK-JNK axis signaling abrogated GFP-BAX translocation after ONC. Conclusions A comparison between BAX activation kinetics in tissue culture cells and in cells of a complex tissue environment shows distinct differences indicating that caution should be used when translating findings from one condition to the other. RGCs exhibit both a delay between translocation and permeabilization and the ability for translocated BAX to be retrotranslocated, suggesting several stages at which intervention of the activation process could be exploited in the design of a therapeutic strategy.
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29
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Lagali PS, Shanmugalingam U, Baker AN, Mezey N, Smith PD, Coupland SG, Tsilfidis C. Assessment of the uniform field electroretinogram for mouse retinal ganglion cell functional analysis. Doc Ophthalmol 2023:10.1007/s10633-023-09933-y. [PMID: 37106219 DOI: 10.1007/s10633-023-09933-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 03/26/2023] [Indexed: 04/29/2023]
Abstract
PURPOSE The uniform field electroretinogram (UF-ERG) has been suggested as an alternative to the pattern electroretinogram (PERG) for non-invasive assessment of retinal ganglion cell (RGC) function in primates. We evaluated the validity of the UF-ERG to assess mouse RGC activity in vivo. METHODS Unilateral optic nerve crush (ONC) was performed on adult C57BL/6J mice. Contralateral eyes with uncrushed optic nerves and eyes from surgically naive mice served as experimental controls. Electrophysiological visual assessment was performed at 12 weeks post-ONC. Flash-mediated visual-evoked cortical potentials (VEPs) were measured to confirm the robustness of the ONC procedure. Full-field flash ERGs were used to interrogate photoreceptor and retinal bipolar cell function. RGC function was assessed with pattern ERGs. Summed onset and offset UF-ERG responses to alternating dark and light uniform field flash stimuli of different intensities and wavelengths were recorded from ONC and control eyes, and relative differences were compared to the PERG results. Following electrophysiological analysis, RGC loss was monitored by immunohistochemical staining of the RGC marker protein, RBPMS, in post-mortem retinal tissues. RESULTS ONC dramatically impacts RGC integrity and optic nerve function, demonstrated by reduced RGC counts and near complete elimination of VEPs. ONC did not affect scotopic ERG a-wave and b-wave amplitudes, while PERG amplitudes of eyes subjected to ONC were reduced by approximately 50% compared to controls. Summation of ON and OFF UF-ERG responses did not reveal statistically significant differences between ONC and control eyes, regardless of visual stimulus. CONCLUSIONS PERG responses are markedly impaired upon ONC, while UF-ERG responses are not significantly affected by surgical trauma to RGC axons in mice. The more closely related pattern and uniform field ERGs recorded in primates suggests species-specific differences in RGC features or subpopulations corresponding to PERG and UF-ERG response generators, limiting the utility of the UF-ERG for mouse RGC functional analysis.
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Affiliation(s)
- Pamela S Lagali
- Neuroscience Program, Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada
- University of Ottawa Eye Institute, The Ottawa Hospital, Ottawa, ON, K1H 8L6, Canada
| | | | - Adam N Baker
- Neuroscience Program, Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada
- University of Ottawa Eye Institute, The Ottawa Hospital, Ottawa, ON, K1H 8L6, Canada
| | - Natalie Mezey
- Department of Neuroscience, Carleton University, Ottawa, ON, Canada
| | - Patrice D Smith
- Department of Neuroscience, Carleton University, Ottawa, ON, Canada
| | - Stuart G Coupland
- University of Ottawa Eye Institute, The Ottawa Hospital, Ottawa, ON, K1H 8L6, Canada
- Department of Ophthalmology, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
| | - Catherine Tsilfidis
- Neuroscience Program, Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada.
- University of Ottawa Eye Institute, The Ottawa Hospital, Ottawa, ON, K1H 8L6, Canada.
- Department of Ophthalmology, University of Ottawa, Ottawa, ON, K1H 8M5, Canada.
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada.
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Tang VTS, Symons RCA, Fourlanos S, Guest D, McKendrick AM. Contrast Increment and Decrement Processing in Individuals With and Without Diabetes. Invest Ophthalmol Vis Sci 2023; 64:26. [PMID: 37083950 PMCID: PMC10132322 DOI: 10.1167/iovs.64.4.26] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/22/2023] Open
Abstract
Purpose Animal models suggest that ON retinal ganglion cells (RGCs) may be more vulnerable to diabetic insult than OFF cells. Using three psychophysical tasks to infer the function of ON and OFF RGCs, we hypothesized that functional responses to contrast increments will be preferentially affected in early diabetes mellitus (DM) compared to contrast decrement responses. Methods Fifty-two people with DM (type 1 or type 2) (mean age = 34.8 years, range = 18-60 years) and 48 age-matched controls (mean age = 35.4 years, range = 18-60 years) participated. Experiment 1 measured contrast sensitivity to increments and decrements at four visual field locations. Experiments 2 and 3 measured visual temporal processing using (i) a response time (RT) task, and (ii) a temporal order judgment task. Mean RT and accuracy were collected for experiment 2, whereas experiment 3 measured temporal thresholds. Results For experiment 1, the DM group showed reduced increment and decrement contrast sensitivity (F (1, 97) = 4.04, P = 0.047) especially for the central location. For experiment 2, those with DM demonstrated slower RT and lower response accuracies to increments and decrements (increments: U = 780, P = 0.01, decrements: U = 749, P = 0.005). For experiment 3, performance was similar between groups (F (1, 91) = 2.52, P = 0.137). Conclusions When assessed cross-sectionally, nonselective functional consequences of retinal neuron damage are present in early DM, particularly for foveal testing. Whether increment-decrement functional indices relate to diabetic retinopathy (DR) progression or poorer visual prognosis in DM requires further study.
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Affiliation(s)
- Vanessa Thien Sze Tang
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Australia
| | - Robert Charles Andrew Symons
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Australia
- Department of Surgery, The University of Melbourne, Parkville, Australia
- Centre for Eye Research Australia, East Melbourne, Australia
- Department of Surgery, Alfred Hospital, Monash University, Australia
| | - Spiros Fourlanos
- Department Diabetes and Endocrinology, Royal Melbourne Hospital, Parkville, Australia
- Department Medicine, Royal Melbourne Hospital, The University of Melbourne, Parkville, Australia
- Australian Centre for Accelerating Diabetes Innovations, The University of Melbourne, Parkville, Australia
| | - Daryl Guest
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Australia
| | - Allison Maree McKendrick
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Australia
- Division of Optometry, University of Western Australia, Perth, Australia
- Lions Eye Institute, Nedlands, Australia
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Boal AM, McGrady NR, Holden JM, Risner ML, Calkins DJ. Retinal ganglion cells adapt to ionic stress in experimental glaucoma. Front Neurosci 2023; 17:1142668. [PMID: 37051140 PMCID: PMC10083336 DOI: 10.3389/fnins.2023.1142668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 03/10/2023] [Indexed: 03/28/2023] Open
Abstract
IntroductionIdentification of early adaptive and maladaptive neuronal stress responses is an important step in developing targeted neuroprotective therapies for degenerative disease. In glaucoma, retinal ganglion cells (RGCs) and their axons undergo progressive degeneration resulting from stress driven by sensitivity to intraocular pressure (IOP). Despite therapies that can effectively manage IOP many patients progress to vision loss, necessitating development of neuronal-based therapies. Evidence from experimental models of glaucoma indicates that early in the disease RGCs experience altered excitability and are challenged with dysregulated potassium (K+) homeostasis. Previously we demonstrated that certain RGC types have distinct excitability profiles and thresholds for depolarization block, which are associated with sensitivity to extracellular K+.MethodsHere, we used our inducible mouse model of glaucoma to investigate how RGC sensitivity to K+ changes with exposure to elevated IOP.ResultsIn controls, conditions of increased K+ enhanced membrane depolarization, reduced action potential generation, and widened action potentials. Consistent with our previous work, 4 weeks of IOP elevation diminished RGC light-and current-evoked responses. Compared to controls, we found that IOP elevation reduced the effects of increased K+ on depolarization block threshold, with IOP-exposed cells maintaining greater excitability. Finally, IOP elevation did not alter axon initial segment dimensions, suggesting that structural plasticity alone cannot explain decreased K+ sensitivity.DiscussionThus, in response to prolonged IOP elevation RGCs undergo an adaptive process that reduces sensitivity to changes in K+ while diminishing excitability. These experiments give insight into the RGC response to IOP stress and lay the groundwork for mechanistic investigation into targets for neuroprotective therapy.
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Luminance Contrast Shifts Dominance Balance between ON and OFF Pathways in Human Vision. J Neurosci 2023; 43:993-1007. [PMID: 36535768 PMCID: PMC9908321 DOI: 10.1523/jneurosci.1672-22.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 11/14/2022] [Accepted: 12/10/2022] [Indexed: 12/23/2022] Open
Abstract
Human vision processes light and dark stimuli in visual scenes with separate ON and OFF neuronal pathways. In nature, stimuli lighter or darker than their local surround have different spatial properties and contrast distributions (Ratliff et al., 2010; Cooper and Norcia, 2015; Rahimi-Nasrabadi et al., 2021). Similarly, in human vision, we show that luminance contrast affects the perception of lights and darks differently. At high contrast, human subjects of both sexes locate dark stimuli faster and more accurately than light stimuli, which is consistent with a visual system dominated by the OFF pathway. However, at low contrast, they locate light stimuli faster and more accurately than dark stimuli, which is consistent with a visual system dominated by the ON pathway. Luminance contrast was strongly correlated with multiple ON/OFF dominance ratios estimated from light/dark ratios of performance errors, missed targets, or reaction times (RTs). All correlations could be demonstrated at multiple eccentricities of the central visual field with an ON-OFF perimetry test implemented in a head-mounted visual display. We conclude that high-contrast stimuli are processed faster and more accurately by OFF pathways than ON pathways. However, the OFF dominance shifts toward ON dominance when stimulus contrast decreases, as expected from the higher-contrast sensitivity of ON cortical pathways (Kremkow et al., 2014; Rahimi-Nasrabadi et al., 2021). The results highlight the importance of contrast polarity in visual field measurements and predict a loss of low-contrast vision in humans with ON pathway deficits, as demonstrated in animal models (Sarnaik et al., 2014).SIGNIFICANCE STATEMENT ON and OFF retino-thalamo-cortical pathways respond differently to luminance contrast. In both animal models and humans, low contrasts drive stronger responses from ON pathways, whereas high contrasts drive stronger responses from OFF pathways. We demonstrate that these ON-OFF pathway differences have a correlate in human vision. At low contrast, humans locate light targets faster and more accurately than dark targets but, as contrast increases, dark targets become more visible than light targets. We also demonstrate that contrast is strongly correlated with multiple light/dark ratios of visual performance in central vision. These results provide a link between neuronal physiology and human vision while emphasizing the importance of stimulus polarity in measurements of visual fields and contrast sensitivity.
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Križaj D, Cordeiro S, Strauß O. Retinal TRP channels: Cell-type-specific regulators of retinal homeostasis and multimodal integration. Prog Retin Eye Res 2023; 92:101114. [PMID: 36163161 PMCID: PMC9897210 DOI: 10.1016/j.preteyeres.2022.101114] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 08/03/2022] [Accepted: 08/08/2022] [Indexed: 02/05/2023]
Abstract
Transient receptor potential (TRP) channels are a widely expressed family of 28 evolutionarily conserved cationic ion channels that operate as primary detectors of chemical and physical stimuli and secondary effectors of metabotropic and ionotropic receptors. In vertebrates, the channels are grouped into six related families: TRPC, TRPV, TRPM, TRPA, TRPML, and TRPP. As sensory transducers, TRP channels are ubiquitously expressed across the body and the CNS, mediating critical functions in mechanosensation, nociception, chemosensing, thermosensing, and phototransduction. This article surveys current knowledge about the expression and function of the TRP family in vertebrate retinas, which, while dedicated to transduction and transmission of visual information, are highly susceptible to non-visual stimuli. Every retinal cell expresses multiple TRP subunits, with recent evidence establishing their critical roles in paradigmatic aspects of vertebrate vision that include TRPM1-dependent transduction of ON bipolar signaling, TRPC6/7-mediated ganglion cell phototransduction, TRP/TRPL phototransduction in Drosophila and TRPV4-dependent osmoregulation, mechanotransduction, and regulation of inner and outer blood-retina barriers. TRP channels tune light-dependent and independent functions of retinal circuits by modulating the intracellular concentration of the 2nd messenger calcium, with emerging evidence implicating specific subunits in the pathogenesis of debilitating diseases such as glaucoma, ocular trauma, diabetic retinopathy, and ischemia. Elucidation of TRP channel involvement in retinal biology will yield rewards in terms of fundamental understanding of vertebrate vision and therapeutic targeting to treat diseases caused by channel dysfunction or over-activation.
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Affiliation(s)
- David Križaj
- Departments of Ophthalmology, Neurobiology, and Bioengineering, University of Utah, Salt Lake City, USA
| | - Soenke Cordeiro
- Institute of Physiology, Faculty of Medicine, Christian-Albrechts-University Kiel, Germany
| | - Olaf Strauß
- Experimental Ophthalmology, Department of Ophthalmology, Charité - Universitätsmedizin Berlin, a Corporate Member of Freie Universität, Humboldt-University, The Berlin Institute of Health, Berlin, Germany.
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Kovalevskaya MA, Antonyan VB, Muntianova EV, Zueva MV. Risk factors as glaucoma predictors in myopic students. RUSSIAN OPHTHALMOLOGICAL JOURNAL 2022. [DOI: 10.21516/2072-0076-2022-15-4-30-37] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Purpose: identification of early risk factors — predictors of POAG development in students with myopic refraction based on questionnaire and functional test data and the effects of fractal photostimulation (FS). Material and methods. The study involved two clinical groups: the main group of 24 students (48 eyes) with mild to moderate myopia, averagely aged 21.3 ± 0.7 years, and the comparison group (according to FS effects) of 29 patients (58 eyes) with an established diagnosis of stage I–III POAG, averagely aged 58 ± 18 years, and a control group consisting of 66 people (132 eyes, mean age 21.2 ± 1.3 years). The case history of patients and typical complaints were found in questionnaire data. For the two clinical groups, the impact of 10 low-intensity FS sessions was evaluated. Results. A set of features viewed as risk factors for POAG development was determined using the data of the questionaries filled in by the main and comparison groups. The changes in mean IOP values measured before and after an FS course were found to be greater in POAG patients than in myopic students. FS was shown to contribute to IOP stabilization in patients with pre-existing morphological and functional glaucoma changes and the occurrence of accompanying pathologies such as vasospasm, blood pressure fluctuations, and migraine-like pain. After a course of FS, overall photosensitivity increased significantly as compared with the baseline in students with mild and moderate myopia (p < 0.05). Also, a positive effect of an FS course on MD indices in patients with stages IIa and IIIa POAG was confirmed. Conclusion. The research results confirm the need to identify clinical and functional predictors of POAG with a progressive glaucomatous process in students with myopic refraction.
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Affiliation(s)
| | | | | | - M. V. Zueva
- Helmholtz National Medical Research Center of Eye Diseases
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Mohammadi M, Su E, Chew L, Mohammadzadeh V, Caprioli J, Weiss RE, Nouri-Mahdavi K. Comparison of Ganglion Cell Layer and Inner Plexiform Layer Rates of Change in Suspected and Established Glaucoma. Am J Ophthalmol 2022; 249:12-20. [PMID: 36516918 PMCID: PMC10106372 DOI: 10.1016/j.ajo.2022.12.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 11/28/2022] [Accepted: 12/05/2022] [Indexed: 12/14/2022]
Abstract
PURPOSE We compared ganglion cell layer (GCL) and inner plexiform layer (IPL) rates of change (RoC) in patients with glaucoma suspect (GS) and established glaucoma (EG) to test the hypothesis that IPL thickness changes would occur earlier than GCL changes in eyes with early damage. DESIGN Prospective, cohort study. METHODS A total of 64 GS eyes (46 patients) and 112 EG eyes (112 patients) with ≥2 years of follow-up and ≥3 macular optical coherence tomography scans were included. GCL and IPL superpixel thickness measurements were exported. A Bayesian hierarchical model with random intercepts/slopes and random residual variances was fitted to estimate RoC in individual superpixels. Normalized RoC and proportions of superpixels with significantly negative and positive GCL and IPL RoC were compared within the groups. RESULTS The average (SD) follow-up time and number of scans were 3.5 (0.7) years and 4.2 (1.0), respectively, in the GS group and 3.6 (0.4) years and 7.3 (1.1) in the EG group. Mean (SD) normalized RoC was faster for GCL than IPL (-0.69 [0.05] vs -0.33 [0.04]) in the GS group, whereas it was faster for IPL (-0.47 [0.03] vs -0.28 [0.02]) in EG eyes. GCL RoC were significantly negative in 24 of 36 superpixels compared with 8 of 36 for IPL (P < .001) in GS eyes. In the EG group, 23 of 36 superpixels had significant negative IPL RoC compared with 13 of 36 superpixels for GCL (P = .006). CONCLUSIONS GCL thickness is more likely to demonstrate change over time compared with IPL in glaucoma suspects. There is no evidence of preferential IPL thinning in eyes with suspected early glaucoma damage.
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Affiliation(s)
- Massood Mohammadi
- From the Glaucoma Division, Stein Eye Institute, David Geffen School of Medicine (M.M., L.C., V.M., J.C., K.N-M.), University of California Los Angeles, Los Angeles, California, USA
| | - Erica Su
- Department of Biostatistics, Fielding School of Public Health (E.S., R.E.W.), University of California Los Angeles, Los Angeles, California, USA
| | - Leila Chew
- From the Glaucoma Division, Stein Eye Institute, David Geffen School of Medicine (M.M., L.C., V.M., J.C., K.N-M.), University of California Los Angeles, Los Angeles, California, USA
| | - Vahid Mohammadzadeh
- From the Glaucoma Division, Stein Eye Institute, David Geffen School of Medicine (M.M., L.C., V.M., J.C., K.N-M.), University of California Los Angeles, Los Angeles, California, USA
| | - Joseph Caprioli
- From the Glaucoma Division, Stein Eye Institute, David Geffen School of Medicine (M.M., L.C., V.M., J.C., K.N-M.), University of California Los Angeles, Los Angeles, California, USA
| | - Robert E Weiss
- Department of Biostatistics, Fielding School of Public Health (E.S., R.E.W.), University of California Los Angeles, Los Angeles, California, USA
| | - Kouros Nouri-Mahdavi
- From the Glaucoma Division, Stein Eye Institute, David Geffen School of Medicine (M.M., L.C., V.M., J.C., K.N-M.), University of California Los Angeles, Los Angeles, California, USA.
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Garner MA, Strickland RG, Girkin CA, Gross AK. Mechanisms of retinal ganglion cell injury following acute increases in intraocular pressure. FRONTIERS IN OPHTHALMOLOGY 2022; 2:1007103. [PMID: 38983517 PMCID: PMC11182138 DOI: 10.3389/fopht.2022.1007103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 10/26/2022] [Indexed: 07/11/2024]
Abstract
The maintenance of intraocular pressure (IOP) is critical to preserving the pristine optics required for vision. Disturbances in IOP can directly impact the optic nerve and retina, and inner retinal injury can occur following acute and chronic IOP elevation. There are a variety of animal models that have been developed to study the effects of acute and chronic elevation of IOP on the retina, retinal ganglion cell (RGC) morphology, intracellular signaling, gene expression changes, and survival. Acute IOP models induce injury that allows for the study of RGC response to well characterized injury and potential recovery. This review will focus on the initial impact of acute IOP elevation on RGC injury and recovery as these early responses may be the best targets for potential therapeutic interventions to promote RGC survival in glaucoma.
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Affiliation(s)
- Mary Anne Garner
- Department of Neurobiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Ryan G. Strickland
- Department of Neurobiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Christopher A. Girkin
- Department of Neurobiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Alecia K. Gross
- Department of Neurobiology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
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Pitale PM, Shen G, Sigireddi RR, Polo-Prieto M, Park YH, Gibson SE, Westenskow PD, Channa R, Frankfort BJ. Selective vulnerability of the intermediate retinal capillary plexus precedes retinal ganglion cell loss in ocular hypertension. Front Cell Neurosci 2022; 16:1073786. [PMID: 36545655 PMCID: PMC9760765 DOI: 10.3389/fncel.2022.1073786] [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: 10/18/2022] [Accepted: 11/15/2022] [Indexed: 12/08/2022] Open
Abstract
Introduction: Glaucoma, a disease of retinal ganglion cell (RGC) injury and potentially devastating vision loss, is associated with both ocular hypertension (OHT) and reduced ocular blood flow. However, the relationship between OHT and retinal capillary architecture is not well understood. In this project, we studied microvasculature damage in mice exposed to mild levels of induced OHT. Methods: Mild OHT was induced with the microbead model for 2 weeks. At this time point, some retinas were immunostained with CD31 (endothelium), Collagen IV (basement membrane), and RBPMS (RGCs) for z-stack confocal microscopy. We processed these confocal images to distinguish the three retinal capillary plexi (superficial, intermediate, and deep). We manually counted RGC density, analyzed vascular complexity, and identified topographical and spatial vascular features of the retinal capillaries using a combination of novel manual and automated workflows. Other retinas were dissociated and immunopanned to isolate RGCs and amacrine cells (ACs) for hypoxia gene array analysis. Results: RGC counts were normal but there was decreased overall retinal capillary complexity. This reduced complexity could be explained by abnormalities in the intermediate retinal capillary plexus (IRCP) that spared the other plexi. Capillary junction density, vessel length, and vascular area were all significantly reduced, and the number of acellular capillaries was dramatically increased. ACs, which share a neurovascular unit (NVU) with the IRCP, displayed a marked increase in the relative expression of many hypoxia-related genes compared to RGCs from the same preparations. Discussion: We have discovered a rapidly occurring, IRCP-specific, OHT-induced vascular phenotype that precedes RGC loss. AC/IRCP NVU dysfunction may be a mechanistic link for early vascular remodeling in glaucoma.
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Affiliation(s)
- Priyamvada M. Pitale
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, United States
| | - Guofu Shen
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, United States
| | - Rohini R. Sigireddi
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, United States
| | - Maria Polo-Prieto
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, United States
| | - Yong H. Park
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, United States
| | - Solomon E. Gibson
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, United States,Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States
| | - Peter D. Westenskow
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, United States
| | - Roomasa Channa
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, United States
| | - Benjamin J. Frankfort
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, United States,Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States,*Correspondence: Benjamin J. Frankfort
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Gallego-Ortega A, Norte-Muñoz M, Di Pierdomenico J, Avilés-Trigueros M, de la Villa P, Valiente-Soriano FJ, Vidal-Sanz M. Alpha retinal ganglion cells in pigmented mice retina: number and distribution. Front Neuroanat 2022; 16:1054849. [PMID: 36530520 PMCID: PMC9751430 DOI: 10.3389/fnana.2022.1054849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 11/07/2022] [Indexed: 12/03/2022] Open
Abstract
Purpose: To identify and characterize numerically and topographically the population of alpha retinal ganglion cells (αRGCs) and their subtypes, the sustained-response ON-center αRGCs (ONs-αRGCs), which correspond to the type 4 intrinsically photosensitive RGCs (M4-ipRGCs), the transient-response ON-center αRGCs (ONt-αRGCs), the sustained-response OFF-center αRGCs (OFFs-αRGCs), and the transient-response OFF-center αRGCs (OFFt-αRGCs) in the adult pigmented mouse retina.Methods: The αRGC population and its subtypes were studied in flat-mounted retinas and radial sections immunodetected against non-phosphorylated high molecular weight neurofilament subunit (SMI-32) or osteopontin (OPN), two αRGCs pan-markers; Calbindin, expressed in ONs-αRGCs, and amacrines; T-box transcription factor T-brain 2 (Tbr2), a key transcriptional regulator for ipRGC development and maintenance, expressed in ipRGCs and GABA-displaced amacrine cells; OPN4, an anti-melanopsin antibody; or Brn3a and Brn3c, markers of RGCs. The total population of RGCs was counted automatically and αRGCs and its subtypes were counted manually, and color-coded neighborhood maps were used for their topographical representation.Results: The total mean number of αRGCs per retina is 2,252 ± 306 SMI32+αRGCs and 2,315 ± 175 OPN+αRGCs (n = 10), representing 5.08% and 5.22% of the total number of RGCs traced from the optic nerve, respectively. αRGCs are distributed throughout the retina, showing a higher density in the temporal hemiretina. ONs-αRGCs represent ≈36% [841 ± 110 cells (n = 10)] of all αRGCs and are located throughout the retina, with the highest density in the temporal region. ONt-αRGCs represent ≈34% [797 ± 146 cells (n = 10)] of all αRGCs and are mainly located in the central retinal region. OFF-αRGCs represent the remaining 32% of total αRGCs and are divided equally between OFFs-αRGCs and OFFt-αRGCs [363 ± 50 cells (n = 10) and 376 ± 36 cells (n = 10), respectively]. OFFs-αRGCs are mainly located in the supero-temporal peripheral region of the retina and OFFt-αRGCs in the mid-peripheral region of the retina, especially in the infero-temporal region.Conclusions: The combination of specific antibodies is a useful tool to identify and study αRGCs and their subtypes. αRGCs are distributed throughout the retina presenting higher density in the temporal area. The sustained ON and OFF response subtypes are mainly located in the periphery while the transient ON and OFF response subtypes are found in the central regions of the retina.
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Affiliation(s)
- Alejandro Gallego-Ortega
- Department of Ophthalmology, Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca (IMIB-Arrixaca), Universidad de Murcia, Murcia, Spain
| | - María Norte-Muñoz
- Department of Ophthalmology, Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca (IMIB-Arrixaca), Universidad de Murcia, Murcia, Spain
| | - Johnny Di Pierdomenico
- Department of Ophthalmology, Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca (IMIB-Arrixaca), Universidad de Murcia, Murcia, Spain
| | - Marcelino Avilés-Trigueros
- Department of Ophthalmology, Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca (IMIB-Arrixaca), Universidad de Murcia, Murcia, Spain
| | - Pedro de la Villa
- Department of Systems Biology, Laboratory of Visual Neurophysiology, School of Medicine and Health Sciences, University of Alcalá, Alcalá de Henares, Spain
- Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Hospital Ramón y Cajal, Madrid, Spain
| | - Francisco Javier Valiente-Soriano
- Department of Ophthalmology, Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca (IMIB-Arrixaca), Universidad de Murcia, Murcia, Spain
- *Correspondence: Manuel Vidal-Sanz Francisco Javier Valiente-Soriano
| | - Manuel Vidal-Sanz
- Department of Ophthalmology, Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca (IMIB-Arrixaca), Universidad de Murcia, Murcia, Spain
- *Correspondence: Manuel Vidal-Sanz Francisco Javier Valiente-Soriano
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Li L, Feng X, Fang F, Miller DA, Zhang S, Zhuang P, Huang H, Liu P, Liu J, Sredar N, Liu L, Sun Y, Duan X, Goldberg JL, Zhang HF, Hu Y. Longitudinal in vivo Ca 2+ imaging reveals dynamic activity changes of diseased retinal ganglion cells at the single-cell level. Proc Natl Acad Sci U S A 2022; 119:e2206829119. [PMID: 36409915 PMCID: PMC9889883 DOI: 10.1073/pnas.2206829119] [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: 04/19/2022] [Accepted: 10/05/2022] [Indexed: 11/22/2022] Open
Abstract
Retinal ganglion cells (RGCs) are heterogeneous projection neurons that convey distinct visual features from the retina to brain. Here, we present a high-throughput in vivo RGC activity assay in response to light stimulation using noninvasive Ca2+ imaging of thousands of RGCs simultaneously in living mice. Population and single-cell analyses of longitudinal RGC Ca2+ imaging reveal distinct functional responses of RGCs and unprecedented individual RGC activity conversions during traumatic and glaucomatous degeneration. This study establishes a foundation for future in vivo RGC function classifications and longitudinal activity evaluations using more advanced imaging techniques and visual stimuli under normal, disease, and neural repair conditions. These analyses can be performed at both the population and single-cell levels using temporal and spatial information, which will be invaluable for understanding RGC pathophysiology and identifying functional biomarkers for diverse optic neuropathies.
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Affiliation(s)
- Liang Li
- Spencer Center for Vision Research, Department of Ophthalmology, Byers Eye Institute at Stanford University School of Medicine, Palo Alto, CA94304
| | - Xue Feng
- Spencer Center for Vision Research, Department of Ophthalmology, Byers Eye Institute at Stanford University School of Medicine, Palo Alto, CA94304
| | - Fang Fang
- Spencer Center for Vision Research, Department of Ophthalmology, Byers Eye Institute at Stanford University School of Medicine, Palo Alto, CA94304
- Department of Ophthalmology, The Second Xiangya Hospital, Central South University, Changsha410011, China
| | - David A. Miller
- Department of Biomedical Engineering, Northwestern University, Evanston, IL60208
| | - Shaobo Zhang
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA94143
| | - Pei Zhuang
- Spencer Center for Vision Research, Department of Ophthalmology, Byers Eye Institute at Stanford University School of Medicine, Palo Alto, CA94304
| | - Haoliang Huang
- Spencer Center for Vision Research, Department of Ophthalmology, Byers Eye Institute at Stanford University School of Medicine, Palo Alto, CA94304
| | - Pingting Liu
- Spencer Center for Vision Research, Department of Ophthalmology, Byers Eye Institute at Stanford University School of Medicine, Palo Alto, CA94304
| | - Junting Liu
- Spencer Center for Vision Research, Department of Ophthalmology, Byers Eye Institute at Stanford University School of Medicine, Palo Alto, CA94304
| | - Nripun Sredar
- Spencer Center for Vision Research, Department of Ophthalmology, Byers Eye Institute at Stanford University School of Medicine, Palo Alto, CA94304
| | - Liang Liu
- Spencer Center for Vision Research, Department of Ophthalmology, Byers Eye Institute at Stanford University School of Medicine, Palo Alto, CA94304
| | - Yang Sun
- Spencer Center for Vision Research, Department of Ophthalmology, Byers Eye Institute at Stanford University School of Medicine, Palo Alto, CA94304
| | - Xin Duan
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA94143
| | - Jeffrey L. Goldberg
- Spencer Center for Vision Research, Department of Ophthalmology, Byers Eye Institute at Stanford University School of Medicine, Palo Alto, CA94304
| | - Hao F. Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, IL60208
| | - Yang Hu
- Spencer Center for Vision Research, Department of Ophthalmology, Byers Eye Institute at Stanford University School of Medicine, Palo Alto, CA94304
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Norcia AM, Yakovleva A, Jehangir N, Goldberg JL. Preferential Loss of Contrast Decrement Responses in Human Glaucoma. Invest Ophthalmol Vis Sci 2022; 63:16. [PMID: 36264656 PMCID: PMC9587510 DOI: 10.1167/iovs.63.11.16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 08/14/2022] [Indexed: 11/24/2022] Open
Abstract
Purpose The purpose of this study was to determine whether glaucoma in human patients produces preferential damage to OFF visual pathways, as suggested by animal experimental models, patient electroretinogram (ERG), and retinal imaging data. Methods Steady-state visual evoked potentials (SSVEPs) were recorded monocularly from 50 patients with glaucoma and 28 age-similar controls in response to equal Weber contrast increments and decrements presented using 2.73 hertz (Hz) sawtooth temporal waveforms. Results The eyes of patients with glaucoma were separated into mild (better than -6 decibel [dB] mean deviation; n = 28) and moderate to severe (worse than -6 dB mean deviation, n = 22) groups based on their Humphrey 24-2 visual field measurements. Response amplitudes and phases from the two glaucoma-severity groups were compared to controls at the group level. SSVEP amplitudes were depressed in both glaucoma groups, more so in the moderate to severe glaucoma group. The differences between controls and the moderate-severe glaucoma groups were more statistically reliable for decrements than for increments. Mean responses to decremental sawtooth stimuli were larger than those to increments in controls and in the mild glaucoma but not in the moderate to severe glaucoma group at the first harmonic. OFF/decrement responses at the first harmonic were faster in controls, but not in patients. Conclusions The observed pattern of preferential loss of decremental responses in human glaucoma is consistent with prior reports of selective damage to OFF retinal ganglion cells in murine models and in data from human ERG and retinal imaging. These data motivate pursuit of SSVEP as a biomarker for glaucoma progression.
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Affiliation(s)
- Anthony M. Norcia
- Department of Psychology, Wu Tsai Neurosciences Institute, Stanford University, Stanford, California, United States
| | - Alexandra Yakovleva
- Spencer Center for Vision Research, Byers Eye Institute, Department of Ophthalmology, Stanford University, Stanford, California, United States
| | - Naz Jehangir
- Spencer Center for Vision Research, Byers Eye Institute, Department of Ophthalmology, Stanford University, Stanford, California, United States
| | - Jeffrey L. Goldberg
- Spencer Center for Vision Research, Byers Eye Institute, Department of Ophthalmology, Stanford University, Stanford, California, United States
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McGrady NR, Holden JM, Ribeiro M, Boal AM, Risner ML, Calkins DJ. Axon hyperexcitability in the contralateral projection following unilateral optic nerve crush in mice. Brain Commun 2022; 4:fcac251. [PMID: 36267329 PMCID: PMC9576152 DOI: 10.1093/braincomms/fcac251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 08/02/2022] [Accepted: 10/01/2022] [Indexed: 11/07/2022] Open
Abstract
Optic neuropathies are characterized by degeneration of retinal ganglion cell axonal projections to the brain, including acute conditions like optic nerve trauma and progressive conditions such as glaucoma. Despite different aetiologies, retinal ganglion cell axon degeneration in traumatic optic neuropathy and glaucoma share common pathological signatures. We compared how early pathogenesis of optic nerve trauma and glaucoma influence axon function in the mouse optic projection. We assessed pathology by measuring anterograde axonal transport from retina to superior colliculus, current-evoked optic nerve compound action potential and retinal ganglion cell density 1 week following unilateral optic nerve crush or intraocular pressure elevation. Nerve crush reduced axon transport, compound axon potential and retinal ganglion cell density, which were unaffected by intraocular pressure elevation. Surprisingly, optic nerves contralateral to crush demonstrated 5-fold enhanced excitability in compound action potential compared with naïve nerves. Enhanced excitability in contralateral sham nerves is not due to increased accumulation of voltage-gated sodium channel 1.6, or ectopic voltage-gated sodium channel 1.2 expression within nodes of Ranvier. Our results indicate hyperexcitability is driven by intrinsic responses of αON-sustained retinal ganglion cells. We found αON-sustained retinal ganglion cells in contralateral, sham and eyes demonstrated increased responses to depolarizing currents compared with those from naïve eyes, while light-driven responses remained intact. Dendritic arbours of αON-sustained retinal ganglion cells of the sham eye were like naïve, but soma area and non-phosphorylated neurofilament H increased. Current- and light-evoked responses of sham αOFF-sustained retinal ganglion cells remained stable along with somato-dendritic morphologies. In retinas directly affected by crush, light responses of αON- and αOFF-sustained retinal ganglion cells diminished compared with naïve cells along with decreased dendritic field area or branch points. Like light responses, αOFF-sustained retinal ganglion cell current-evoked responses diminished, but surprisingly, αON-sustained retinal ganglion cell responses were similar to those from naïve retinas. Optic nerve crush reduced dendritic length and area in αON-sustained retinal ganglion cells in eyes ipsilateral to injury, while crush significantly reduced dendritic branching in αOFF-sustained retinal ganglion cells. Interestingly, 1 week of intraocular pressure elevation only affected αOFF-sustained retinal ganglion cell physiology, depolarizing resting membrane potential in cells of affected eyes and blunting current-evoked responses in cells of saline-injected eyes. Collectively, our results suggest that neither saline nor sham surgery provide a true control, chronic versus acute optic neuropathies differentially affect retinal ganglion cells composing the ON and OFF pathways, and acute stress can have near-term effects on the contralateral projection.
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Affiliation(s)
- Nolan R McGrady
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, AA7103 MCN/VUIIS, 1161 21st Ave. S., Nashville, TN 37232, USA
| | - Joseph M Holden
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, AA7103 MCN/VUIIS, 1161 21st Ave. S., Nashville, TN 37232, USA
| | - Marcio Ribeiro
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, AA7103 MCN/VUIIS, 1161 21st Ave. S., Nashville, TN 37232, USA
| | - Andrew M Boal
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, AA7103 MCN/VUIIS, 1161 21st Ave. S., Nashville, TN 37232, USA
| | - Michael L Risner
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, AA7103 MCN/VUIIS, 1161 21st Ave. S., Nashville, TN 37232, USA
| | - David J Calkins
- Correspondence to: David J. Calkins, PhD AA7103 MCN/VUIIS 1161 21st Ave. S., Nashville, TN 37232, USA E-mail:
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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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Gao J, Provencio I, Liu X. Intrinsically photosensitive retinal ganglion cells in glaucoma. Front Cell Neurosci 2022; 16:992747. [PMID: 36212698 PMCID: PMC9537624 DOI: 10.3389/fncel.2022.992747] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 09/05/2022] [Indexed: 11/30/2022] Open
Abstract
Glaucoma is a group of eye diseases afflicting more than 70 million people worldwide. It is characterized by damage to retinal ganglion cells (RGCs) that ultimately leads to the death of the cells and vision loss. The diversity of RGC types has been appreciated for decades, and studies, including ours, have shown that RGCs degenerate and die in a type-specific manner in rodent models of glaucoma. The type-specific loss of RGCs results in differential damage to visual and non-visual functions. One type of RGC, the intrinsically photosensitive retinal ganglion cell (ipRGC), expressing the photopigment melanopsin, serves a broad array of non-visual responses to light. Since its discovery, six subtypes of ipRGC have been described, each contributing to various image-forming and non-image-forming functions such as circadian photoentrainment, the pupillary light reflex, the photic control of mood and sleep, and visual contrast sensitivity. We recently demonstrated a link between type-specific ipRGC survival and behavioral deficits in a mouse model of chronic ocular hypertension. This review focuses on the type-specific ipRGC degeneration and associated behavioral changes in animal models and glaucoma patients. A better understanding of how glaucomatous insult impacts the ipRGC-based circuits will have broad impacts on improving the treatment of glaucoma-associated non-visual disorders.
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Affiliation(s)
- Jingyi Gao
- Department of Biology, University of Virginia, Charlottesville, VA, United States
| | - Ignacio Provencio
- Department of Biology, University of Virginia, Charlottesville, VA, United States
- Department of Ophthalmology, University of Virginia, Charlottesville, VA, United States
- Program in Fundamental Neuroscience, University of Virginia, Charlottesville, VA, United States
| | - Xiaorong Liu
- Department of Biology, University of Virginia, Charlottesville, VA, United States
- Department of Ophthalmology, University of Virginia, Charlottesville, VA, United States
- Program in Fundamental Neuroscience, University of Virginia, Charlottesville, VA, United States
- Department of Psychology, University of Virginia, Charlottesville, VA, United States
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Meah A, Boodram V, Bucinca-Cupallari F, Lim H. Axonal architecture of the mouse inner retina revealed by second harmonic generation. PNAS NEXUS 2022; 1:pgac160. [PMID: 36106183 PMCID: PMC9463061 DOI: 10.1093/pnasnexus/pgac160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 08/11/2022] [Indexed: 01/29/2023]
Abstract
We describe a novel method for visualizing the network of axons in the unlabeled fresh wholemount retina. The intrinsic radiation of second harmonic generation (SHG) was utilized to visualize single axons of all major retinal neurons, i.e., photoreceptors, horizontal cells, bipolar cells, amacrine cells, and the retinal ganglion cells. The cell types of SHG+ axons were determined using transgenic GFP/YFP mice. New findings were obtained with retinal SHG imaging: Müller cells do not maintain uniformly polarized microtubules in the processes; SHG+ axons of bipolar cells terminate in the inner plexiform layer (IPL) in a subtype-specific manner; a subset of amacrine cells, presumably the axon-bearing types, emits SHG; and the axon-like neurites of amacrine cells provide a cytoskeletal scaffolding for the IPL stratification. To demonstrate the utility, retinal SHG imaging was applied to testing whether the inner retina is preserved in glaucoma, using DBA/2 mice as a model of glaucoma and DBA/2-Gpnmb+ as the nonglaucomatous control. It was found that the morphology of the inner retina was largely intact in glaucoma and the presynaptic compartments to the retinal ganglion cells were uncompromised. It proves retinal SHG imaging as a promising technology for studying the physiological and diseased retinas in 3D.
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Affiliation(s)
- Arafat Meah
- Department of Physics and Astronomy, Hunter College, New York, NY 10065, USA
| | - Vinessia Boodram
- Department of Physics and Astronomy, Hunter College, New York, NY 10065, USA
| | - Festa Bucinca-Cupallari
- Department of Physics and Astronomy, Hunter College, New York, NY 10065, USA,The Graduate Centre of the City University of New York, New York, NY 10065, USA
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Boal AM, McGrady NR, Risner ML, Calkins DJ. Sensitivity to extracellular potassium underlies type-intrinsic differences in retinal ganglion cell excitability. Front Cell Neurosci 2022; 16:966425. [PMID: 35990894 PMCID: PMC9390602 DOI: 10.3389/fncel.2022.966425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 07/20/2022] [Indexed: 11/13/2022] Open
Abstract
Neuronal type-specific physiologic heterogeneity can be driven by both extrinsic and intrinsic mechanisms. In retinal ganglion cells (RGCs), which carry visual information from the retina to central targets, evidence suggests intrinsic properties shaping action potential (AP) generation significantly impact the responses of RGCs to visual stimuli. Here, we explored how differences in intrinsic excitability further distinguish two RCG types with distinct presynaptic circuits, alpha ON-sustained (αON-S) cells and alpha OFF-sustained (αOFF-S) cells. We found that αOFF-S RGCs are more excitable to modest depolarizing currents than αON-S RGCs but excitability plateaued earlier as depolarization increased (i.e., depolarization block). In addition to differences in depolarization block sensitivity, the two cell types also produced distinct AP shapes with increasing stimulation. αOFF-S AP width and variability increased with depolarization magnitude, which correlated with the onset of depolarization block, while αON-S AP width and variability remained stable. We then tested if differences in depolarization block observed in αON-S and αOFF-S RGCs were due to sensitivity to extracellular potassium. We found αOFF-S RGCs more sensitive to increased extracellular potassium concentration, which shifted αON-S RGC excitability to that of αOFF-S cells under baseline potassium conditions. Finally, we investigated the influence of the axon initial segment (AIS) dimensions on RGC spiking. We found that the relationship between AIS length and evoked spike rate varied not only by cell type, but also by the strength of stimulation, suggesting AIS structure alone cannot fully explain the observed differences RGC excitability. Thus, sensitivity to extracellular potassium contributes to differences in intrinsic excitability, a key factor that shapes how RGCs encode visual information.
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46
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Kimball EC, Quillen S, Pease ME, Keuthan C, Nagalingam A, Zack DJ, Johnson TV, Quigley HA. Aquaporin 4 is not present in normal porcine and human lamina cribrosa. PLoS One 2022; 17:e0268541. [PMID: 35709078 PMCID: PMC9202842 DOI: 10.1371/journal.pone.0268541] [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: 11/29/2021] [Accepted: 05/03/2022] [Indexed: 02/02/2023] Open
Abstract
Aquaporin 4 is absent from astrocytes in the rodent optic nerve head, despite high expression in the retina and myelinated optic nerve. The purpose of this study was to quantify regional aquaporin channel expression in astrocytes of the porcine and human mouse optic nerve (ON). Ocular tissue sections were immunolabeled for aquaporins 1(AQP1), 4(AQP4), and 9(AQP9), myelin basic protein (MBP), glial fibrillary acidic protein (GFAP) and alpha-dystroglycan (αDG) for their presence in retina, lamina, myelin transition zone (MTZ, region just posterior to lamina) and myelinated ON (MON). Semi- quantification of AQP4 labeling & real-time quantitative PCR (qPCR) data were analyzed in retina and ON tissue. Porcine and control human eyes had abundant AQP4 in Müller cells, retinal astrocytes, and myelinated ON (MON), but minimal expression in the lamina cribrosa. AQP1 and AQP9 were present in retina, but not in the lamina. Immunolabeling of GFAP and αDG was similar in lamina, myelin transition zone (MTZ) and MON regions. Semi-quantitative AQP4 labeling was at background level in lamina, increasing in the MTZ, and highest in the MON (lamina vs MTZ, MON; p≤0.05, p≤0.01, respectively). Expression of AQP4 mRNA was minimal in lamina and substantial in MTZ and MON, while GFAP mRNA expression was uniform among the lamina, MTZ, and MON regions. Western blot assay showed AQP4 protein expression in the MON samples, but none was detected in the lamina tissue. The minimal presence of AQP4 in the lamina is a specific regional phenotype of astrocytes in the mammalian optic nerve head.
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Affiliation(s)
- Elizabeth C. Kimball
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Sarah Quillen
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Mary E. Pease
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Casey Keuthan
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Aru Nagalingam
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Donald J. Zack
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Thomas V. Johnson
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Harry A. Quigley
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
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Lee PY, Zhao D, Wong VHY, Chrysostomou V, Crowston JG, Bui BV. The Effect of Aging on Retinal Function and Retinal Ganglion Cell Morphology Following Intraocular Pressure Elevation. Front Aging Neurosci 2022; 14:859265. [PMID: 35645783 PMCID: PMC9133539 DOI: 10.3389/fnagi.2022.859265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 04/04/2022] [Indexed: 11/13/2022] Open
Abstract
Aging and elevated intraocular pressure (IOP) are two major risk factors for glaucomatous optic neuropathy; a condition characterized by the selective, progressive injury, and subsequent loss of retinal ganglion cells (RGCs). We examined how age modified the capacity for RGCs to functionally recover following a reproducible IOP elevation (50 mmHg for 30 min). We found that RGC functional recovery (measured using electroretinography) was complete by 7 days in 3-month-old mice but was delayed in 12-month-old mice until 14 days. At the 7-day recovery endpoint when RGC function had recovered in young but not older eyes, we examined RGC structural responses to IOP-related stress by analyzing RGC dendritic morphology. ON-RGC cell volume was attenuated following IOP elevation in both young and older mice. We also found that following IOP elevation OFF-RGC dendritic morphology became less complex per cell volume in young mice, an effect that was not observed in older eyes. Our data suggest that adaptations in OFF-RGCs in young eyes were associated with better functional recovery 7 days after IOP elevation. Loss of RGC cellular adaptations may account for delayed functional recovery in older eyes.
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Affiliation(s)
- Pei Ying Lee
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Da Zhao
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Vickie H. Y. Wong
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Vicki Chrysostomou
- Singapore Eye Research Institute, Singapore, Singapore,Duke-NUS Medical School, Singapore, Singapore
| | - Jonathan G. Crowston
- Singapore Eye Research Institute, Singapore, Singapore,Duke-NUS Medical School, Singapore, Singapore
| | - Bang V. Bui
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, VIC, Australia,*Correspondence: Bang V. Bui,
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Boccuni I, Fairless R. Retinal Glutamate Neurotransmission: From Physiology to Pathophysiological Mechanisms of Retinal Ganglion Cell Degeneration. Life (Basel) 2022; 12:638. [PMID: 35629305 PMCID: PMC9147752 DOI: 10.3390/life12050638] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 04/22/2022] [Accepted: 04/22/2022] [Indexed: 12/12/2022] Open
Abstract
Glutamate neurotransmission and metabolism are finely modulated by the retinal network, where the efficient processing of visual information is shaped by the differential distribution and composition of glutamate receptors and transporters. However, disturbances in glutamate homeostasis can result in glutamate excitotoxicity, a major initiating factor of common neurodegenerative diseases. Within the retina, glutamate excitotoxicity can impair visual transmission by initiating degeneration of neuronal populations, including retinal ganglion cells (RGCs). The vulnerability of RGCs is observed not just as a result of retinal diseases but has also been ascribed to other common neurodegenerative and peripheral diseases. In this review, we describe the vulnerability of RGCs to glutamate excitotoxicity and the contribution of different glutamate receptors and transporters to this. In particular, we focus on the N-methyl-d-aspartate (NMDA) receptor as the major effector of glutamate-induced mechanisms of neurodegeneration, including impairment of calcium homeostasis, changes in gene expression and signalling, and mitochondrial dysfunction, as well as the role of endoplasmic reticular stress. Due to recent developments in the search for modulators of NMDA receptor signalling, novel neuroprotective strategies may be on the horizon.
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Affiliation(s)
- Isabella Boccuni
- Institute for Physiology and Pathophysiology, Heidelberg University, 69120 Heidelberg, Germany
- Department of Neurology, University Clinic Heidelberg, 69120 Heidelberg, Germany;
| | - Richard Fairless
- Department of Neurology, University Clinic Heidelberg, 69120 Heidelberg, Germany;
- Clinical Cooperation Unit (CCU) Neurooncology, German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
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Ramamoorthy P, Alexander NL, Frankfort BJ. Abnormal perception of pattern-induced flicker colors in subjects with glaucoma. J Vis 2022; 22:5. [PMID: 35133432 PMCID: PMC8842510 DOI: 10.1167/jov.22.2.5] [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] [Indexed: 12/03/2022] Open
Abstract
Pattern-induced flicker colors (PIFCs) are subjective colors that can be elicited with rotation of an achromatic stimulus such as the Benham disk. The perceptive mechanisms underlying PIFCs are not well-understood, but are thought to be generated primarily by retinal cell types which may be dysfunctional in glaucoma. Using a custom computer-based system, we tested PIFC perception across several Benham disk parameters, including the rates of acceleration and deceleration, rotational direction, and image contrast in both control and glaucoma subjects. We defined the Benham perception limit (BPL) during acceleration as the rotational speed at which PIFCs were first detected (Benham perception limit for acceleration) and the BPL during deceleration as the rotational speed at which PIFCs were extinguished (Benham perception limit for deceleration). In general, we found that glaucoma subjects perceived PIFCs less frequently than control subjects. For all subjects, we found that slower rates of acceleration and deceleration resulted in a lower Benham perception limit for acceleration and a higher Benham perception limit for deceleration, suggesting that PIFCs were both more easily detected and extinguished. Finally, subjects with glaucoma required increased rotational speeds during acceleration to detect PIFCs under certain conditions. Further study is needed to determine if these findings can be used to enhance clinical detection strategies.
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Affiliation(s)
| | - Nicole L Alexander
- Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA.,
| | - Benjamin J Frankfort
- Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA.,Department of Neuroscience, Baylor College of Medicine, Houston, Texas, USA.,
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50
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Differential susceptibility of retinal ganglion cell subtypes against neurodegenerative diseases. Graefes Arch Clin Exp Ophthalmol 2022; 260:1807-1821. [PMID: 35038014 DOI: 10.1007/s00417-022-05556-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 11/27/2021] [Accepted: 01/06/2022] [Indexed: 12/15/2022] Open
Abstract
Retinal ganglion cells (RGCs) are essential to propagate external visual information from the retina to the brain. Death of RGCs is speculated to be closely correlated with blinding retinal diseases, such as glaucoma and traumatic optic neuropathy (TON). Emerging innovative technologies have helped refine and standardize the classification of RGCs; at present, they are classified into more than 40 subpopulations in mammals. These RGC subtypes are identified by a combination of anatomical morphologies, electrophysiological functions, and genetic profiles. Increasing evidence suggests that neurodegenerative diseases do not collectively affect the RGCs. In fact, which RGC subtype exhibits the strongest or weakest susceptibility is hotly debated. Although a consensus has not yet been reached, it is certain that assorted RGCs display differential susceptibility against irreversible degeneration. Interestingly, a single RGC subtype can exhibit various vulnerabilities to optic nerve damage in diverse injury models. Thus, elucidating how susceptible RGC subtypes are to various injuries can protect vulnerable RGCs from damage and improve the possibility of preventing and treating visual impairment caused by neurodegenerative diseases. In this review, we summarize in detail the progress and status quo of research on the type-specific susceptibility of RGCs and point out current limitations and the possible directions for future research in this field.
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