Eye Diseases Commons^™

Modeling Inherited Retinal Disease In Zebrafish, Meet Patel

Theses and Dissertations--Biology

Inherited retinal diseases (IRDs) affect millions of people worldwide. Majority of IRDs are caused by degeneration of rod and cone photoreceptor cells (PRCs) due to gene mutations. The overarching goal of my dissertation is to model and evaluate the molecular role of various gene candidates involved in IRDs such as cone rod dystrophy (CRD) and retinitis pigmentosa (RP).

Mutations in CDHR1, a photoreceptor specific cadherin have been associated with CRD and recapitulated in mouse CDHR1 knockouts. However, the molecular function of CDHR1 remains unknown. CDHR1 has been shown to localize at the leading edge of murine rod nascent outer segment …

Ocular Blood Flow And Retinal Vascular Reactivity In Alzheimer’S Disease: A Systematic Review Of Retinal Images, Tori Sayers, Alexa Nichols, Amin Ibrahim, Igor Zwir, Andrew Tsin, Lorena Flores-Hernandez, Gladys E. Maestre, Jesus D. Melgarejo

Research Colloquium

Background: Alzheimer’s disease (AD) is the most common form of dementia and one of the leading causes of disability and death in the United States¹. Research efforts aim to identify pathological changes that may help support earlier detection of AD and lead to more accessible tools for monitoring disease progression². The retina is being explored as a potential non-invasive marker of AD, reflecting the shared embryology and microvasculature features between the retina and the brain. Although research has focused on structural changes in retinal vessel diameters and density, few studies have evaluated functional markers of retinal …

Zika Virus Impairs Autophagic Flux In Trabecular Meshwork, And Inhibition Of Autophagy Restricts Ocular Viral Transmission And Associated Pathology, Faraz Ahmad, Prince Kumar, Pallav Singh, Trupti Joshi, Pawan Kumar Singh

Biomedical Sciences

Zika virus (ZIKV) is the lone member of Flavivirus family known to cause congenital glaucoma following in utero exposure. The molecular mechanisms of ZIKV-induced glaucoma remain elusive, with no known therapeutic modalities. Autophagy plays a dual role in viral infections and glaucoma pathogenesis. However, how ZIKV  interferes with autophagic pathways in the trabecular meshwork (TM) and whether autophagy contributes to ZIKV-induced ocular complications remains elusive. Here, we investigated the role of autophagy in ZIKV ocular pathogenesis utilizing a primary human trabecular meshwork cells (HTMC) and IFNAR1-/- mouse model of ocular infection. Our results show that ZIKV permissively infects HTMC, elicits …

Integrating Bulk And Single-Cell Transcriptomics To Investigate Intratumor Heterogeneity, Shuai Guo

Dissertations and Theses (Open Access)

Cancers are heterogeneous mixtures of tumor and surrounding cells, where each component comprises multiple distinct sub-types and/or states. Understanding the cell-type-specific contributions is critical for advancing cancer biology, yet high-throughput expression profiles from tumor tissues only represent combined signals from all diverse cellular sources. Bulk deconvolution with single-cell/nucleus (sc/sn) RNA-seq data has emerged as a powerful approach to dissect both cellular composition and cell-type-specific expression patterns, yet the technological discrepancy across sequencing platforms limits accuracy.

To systematically evaluate the impact of platform discrepancies on bulk deconvolution, we first generated a benchmark dataset of 24 healthy retinas with paired bulk and …

Contribution Of Pannexin Channels To Afterimage Signals In The Amphibian Retina, Yufei Liu, Nick Libian, Zheng Jiang, Wen Shen

Faculty, Staff and Students Publications

Pannexin 1 (Panx1) forms large-pore, single-membrane channels that connect the intracellular and extracellular environments, permitting the passage of ions and small molecules such as ATP. Panx1 channels are involved in diverse signaling pathways that contribute to various physiological processes, including sensory processing, although their precise mechanisms of action remain incompletely understood. This study reveals a Panx1-mediated mechanism regulating visual signal processing in the amphibian retina. Using immunolabeling and confocal imaging, we localized Panx1 channels in the cone-dominated On-bipolar cells, specifically at both somas and axon terminals. Whole-cell patch-clamp recordings showed that these channels have high permeability to Cl⁻ ions, which …

Diabetic Retinopathy: A Pathophysiological Discussion, Nathanael C. Nicholls

Senior Honors Theses

Diabetic retinopathy is a severe complication of diabetes that is capable of causing vision loss or blindness. As a result of hyperglycemia, the disease increases oxidative stress and activates biochemical processes such as the Hippo pathway and the complement system to cause significant damage to the retina. Overexpression of BTG1 and microRNA-183 enables activation of biochemical pathways that lead to negative effects on the retinal vascular endothelium including angiogenesis and inflammation. Conventional methods of diagnosis for diabetic retinopathy include fundus examination, nucleoside detection, and optical coherence tomography angiography. Photocoagulation and hormonal intravitreal injection are the most popular current treatments, while …

Htr1b Is Necessary For Normal Retinal Function In Mice, Solomon E Gibson, Xiaofeng Tao, Guofu Shen, Justin Ma, Yong H Park, Maria Polo-Prieto, Benjamin J Frankfort

Faculty, Staff and Students Publications

Introduction: Serotonin (5-HT) is a neurotransmitter that is involved in retinal development, physiology, and vision, yet the specific contribution of individual 5-HT receptors to retinal function is poorly characterized. We identified 5-HT receptor 1B (Htr1b) as a potential key regulator of serotonergic signaling in the retina.

Methods: Htr1b localization was examined using RNAseq and in situ labeling. Retinal structure was assessed using histology and SD-OCT. Visual function was evaluated using optomotor behavioral experiments. Retinal function was characterized in vivo using electroretinography (ERG) and ex vivo using multielectrode array (MEA) recordings.

Results: Htr1b transcript and HTR1B protein localized primarily …

Altered Outer Retinal Structure, Electrophysiology And Visual Perception In Parkinson's Disease, Katie K N Tran, Pei Ying Lee, David I Finkelstein, Allison M Mckendrick, Bao N Nguyen, Bang V Bui, Christine T O Nguyen

Faculty, Staff and Student Publications

BACKGROUND: Visual biomarkers of Parkinson's disease (PD) are attractive as the retina is an outpouching of the brain. Although inner retinal neurodegeneration in PD is well-established this has overlap with other neurodegenerative diseases and thus outer retinal (photoreceptor) measures warrant further investigation.

OBJECTIVE: To examine in a cross-sectional study whether clinically implementable measures targeting outer retinal function and structure can differentiate PD from healthy ageing and whether these are sensitive to intraday levodopa (L-DOPA) dosing.

METHODS: Centre-surround perceptual contrast suppression, macular visual field sensitivity, colour discrimination, light-adapted electroretinography and optical coherence tomography (OCT) were tested in PD participants (n = …

The Atoh1-Cre Knock-In Allele Ectopically Labels A Subpopulation Of Amacrine Cells And Bipolar Cells In Mouse Retina, Sih-Rong Wu, Huda Y Zoghbi

Duncan NRI Faculty and Staff Publications

The retina has diverse neuronal cell types derived from a common pool of retinal progenitors. Many molecular drivers, mostly transcription factors, have been identified to promote different cell fates. In Drosophila, atonal is required for specifying photoreceptors. In mice, there are two closely related atonal homologs, Atoh1 and Atoh7. While Atoh7 is known to promote the genesis of retinal ganglion cells, there is no study on the function of Atoh1 in retinal development. Here, we crossed Atoh1^Cre/+ mice to mice carrying a Cre-dependent TdTomato reporter to track potential Atoh1-lineage neurons in retinas. We characterized a heterogeneous …

Insulin In Combination With N-Acetylcysteine Protects Hypoxia-Induced Toxicity In 661w Cells, Lili M. Guerra, Laura Valdez, Benxu Cheng, Andrew Tsin

Research Colloquium

Background: Proliferative diabetic retinopathy (PDR) is the leading cause of blindness among working-age adults. Photoreceptors are the most numerous and metabolically demanding cells in the retina thus oxygen is essential for retinal function. It has been reported that photoreceptors found in rat retina are specifically vulnerable to hypoxia. Hypoxia-induced metabolic stress leads to photoreceptor atrophy and retinopathy. Furthermore, photoreceptor cell death is known to occur mainly through apoptosis. However, the protection of hypoxia-induced-cytotoxicity in cone photoreceptor cells has not been investigated extensively. The aim of this study was to determine whether co-treatment of insulin and the N-Acetyl-L-Cysteine (NAC) (a free …

Soy Isoflavone Reduces Lps-Induced Acute Lung Injury Via Increasing Aquaporin 1 And Aquaporin 5 In Rats, Yuan-Hao Lee, W Wade Kothmann, Ya-Ping Lin, Alice Z Chuang, Jeffrey S Diamond, John O'Brien

Faculty, Staff and Student Publications

Synaptic plasticity is a fundamental feature of the CNS that controls the magnitude of signal transmission between communicating cells. Many electrical synapses exhibit substantial plasticity that modulates the degree of coupling within groups of neurons, alters the fidelity of signal transmission, or even reconfigures functional circuits. In several known examples, such plasticity depends on calcium and is associated with neuronal activity. Calcium-driven signaling is known to promote potentiation of electrical synapses in fish Mauthner cells, mammalian retinal AII amacrine cells, and inferior olive neurons, and to promote depression in thalamic reticular neurons. To measure local calcium dynamics

Non-Canonical Wnt Signaling In The Eye, Ruchi Shah, Cynthia Amador, Steven T Chun, Sean Ghiam, Mehrnoosh Saghizadeh, Andrei A Kramerov, Alexander V Ljubimov

Faculty, Staff and Student Publications

Wnt signaling comprises a group of complex signal transduction pathways that play critical roles in cell proliferation, differentiation, and apoptosis during development, as well as in stem cell maintenance and adult tissue homeostasis. Wnt pathways are classified into two major groups, canonical (β-catenin-dependent) or non-canonical (β-catenin-independent). Most previous studies in the eye have focused on canonical Wnt signaling, and the role of non-canonical signaling remains poorly understood. Additionally, the crosstalk between canonical and non-canonical Wnt signaling in the eye has hardly been explored. In this review, we present an overview of available data on ocular non-canonical Wnt signaling, including developmental …

Overcoming The Challenges To Clinical Development Of X-Linked Retinitis Pigmentosa Therapies: Proceedings Of An Expert Panel, David G Birch, Janet K Cheetham, Stephen P Daiger, Carel Hoyng, Christine Kay, Ian M Macdonald, Mark E Pennesi, Lori S Sullivan

Faculty, Staff and Student Publications

X-linked retinitis pigmentosa (XLRP) is a rare inherited retinal disease manifesting as impaired night vision and peripheral vision loss that progresses to legal blindness. Although several trials of ocular gene therapy for XLRP have been conducted or are in progress, there is currently no approved treatment. In July 2022, the Foundation Fighting Blindness convened an expert panel to examine relevant research and make recommendations for overcoming the challenges and capitalizing on the opportunities in conducting clinical trials of RPGR-targeted therapy for XLRP. Data presented concerned RPGR structure and mutation types known to cause XLRP, RPGR mutation-associated retinal phenotype diversity, patterns …

Effects Of Different Spectrum Of Leds On Retinal Degeneration Through Regulating Endoplasmic Reticulum Stress, Wenyi Chen, Rong Lin, Kunhong Xiao, Kun Yuan, Zhongjiang Chen, Yan Huang

Faculty, Staff and Student Publications

PURPOSE: To evaluate the impact of full-spectrum light-emitting diodes (LEDs) on albino guinea pigs' retina and investigate the roles of short-wavelength opsin (S-opsin) and endoplasmic reticulum (ER) stress in light-induced retinal degeneration (LIRD).

METHODS: Three-week-old albino guinea pigs (n = 30) were distributed into five groups under 12/12 light/dark cycles with indoor natural light (NC; 300-500 lux, n = 6), full-spectrum LEDs (FL; 300 lux, n = 6; 3000 lux, n = 6), and commercial cold-white LEDs (CL; 300 lux, n = 6; 3000 lux, n = 6) and raised for 28 days. Hematoxylin and eosin staining and transmission electron …

High Energy Blue Light Induces Oxidative Stress And Retinal Cell Apoptosis, Jessica Malinsky

Capstone Showcase

Blue light (BL) is a high energy, short wavelength spanning 400 to 500 nm. Found in technological and environmental forms, BL has been shown to induce photochemical damage of the retina by reactive oxygen species (ROS) production. Excess ROS leads to oxidative stress, which disrupts retinal mitochondrial structure and function. As mitochondria amply occupy photoreceptors, they also contribute to oxidative stress due to their selectively significant absorption of BL at 400 to 500 nm. ROS generation that induces oxidative stress subsequently promotes retinal mitochondrial apoptosis. BL filtering and preventative mechanisms have been suggested to improve or repair BL-induced retinal damage, …

Examining The Effects Of Hyperglycemia On Retinal Regeneration, Emmanuella Ec Kyllians

Theses and Dissertations--Biology

Diabetes is a disease that affects how the body processes glucose, leading to a cascade of other complications, one of which is diabetic retinopathy (DR). DR is a neurovascular disease that affects the retina and research has revealed the role of retinal neurodegeneration in its development. Animal models like zebrafish have emerged as important tools for studying the molecular and cellular mechanisms underlying DR. On the other hand, retinitis pigmentosa (RP) is a degenerative disease that involves the progressive degeneration of rods and cones, and hyperglycemia has been found to impair regeneration. Therefore, this study aims to examine the effects …

Heat Shock Protein 90 (Hsp90) System In Health And Disease., Daniella Munezero

Graduate Theses, Dissertations, and Problem Reports (ETD)

Cells rely on heat shock proteins (HSP) to facilitate and regulate the folding of the substrate proteins into their native state, and degradation if misfolding cannot be prevented. HSP90, a member of the HSP family, is a potential target for treatment of cancer and neurodegenerative diseases. Unfortunately, several clinical trials for cancer treatment have been discontinued due to cell toxicity accompanying HSP90 inhibition. HSP90 has four distinct but structurally similar paralogs. HSP90 inhibitors target all the paralogs despite increasing proof of functional differences among the paralogs. Understanding the in vivo function of HSP90 and the role played by each paralog …

Stephen Massey: A Career In Visual Neuroscience, Stephen L Mills, David W Marshak

Faculty, Staff and Student Publications

This review is a memoir by Dr. Stephen C. Massey's longtime collaborator, Dr. Stephen L. Mills, and written, for the most part, in the first person. It also serves as an introduction to the virtual festschrift to celebrate Dr. Massey's retirement. and. The references cited here are only a few of the highlights of Dr. Massey's distinguished career. A complete list is found here: https://pubmed.ncbi.nlm.nih.gov/?term=massey+sc+%28retina+or+photoreceptors%29&sort=date.

Retinal Alpha-Synuclein Accumulation Correlates With Retinal Dysfunction And Structural Thinning In The A53t Mouse Model Of Parkinson’S Disease, Katie K N Tran, Vickie H Y Wong, Anh Hoang, David I Finkelstein, Bang V Bui, Christine T O Nguyen

Faculty, Staff and Student Publications

Abnormal alpha-synuclein (α-SYN) protein deposition has long been recognized as one of the pathological hallmarks of Parkinson's disease's (PD). This study considers the potential utility of PD retinal biomarkers by investigating retinal changes in a well characterized PD model of α-SYN overexpression and how these correspond to the presence of retinal α-SYN. Transgenic A53T homozygous (HOM) mice overexpressing human α-SYN and wildtype (WT) control littermates were assessed at 4, 6, and 14  months of age (male and female,

Effects Of Dietary Ω-3 Polyunsaturated Fatty Acids (N-3 Pufa) In Light Sensitivity Of Retinas Of Mice Models To Prevent Retinal Damage, Aaron Eugene Rice

Longitudinal Scholar's Project

Light-induced retinal degeneration (LIRD) causes photoreceptor cell death in albino mice after exposure to high intensity light for a set period of time (6-24 hours). This causes retinal photoreceptor cell death through apoptosis. From several previous studies, Dr. Mandal’s lab concluded that de novo biosynthesis of ceramide mediates photoreceptor cell death in a LIRD model. Previous studies in Dr. Mandal’s lab has shown that mouse models with higher endogenous ω-3 Polyunsaturated Fatty Acids (n-3 PUFA) generates less ceramide upon neuronal injury and prevent neurodegeneration (Mol Neurobio 2021). There are currently not many available effective therapies for retinal degeneration in humans …

Differential Susceptibility Of Retinal Neurons To The Loss Of Mitochondrial Biogenesis Factor Nrf1, Takae Kiyama, Ching-Kang Chen, Annie Zhang, Chai-An Mao

Faculty, Staff and Student Publications

The retina, the accessible part of the central nervous system, has served as a model system to study the relationship between energy utilization and metabolite supply. When the metabolite supply cannot match the energy demand, retinal neurons are at risk of death. As the powerhouse of eukaryotic cells, mitochondria play a pivotal role in generating ATP, produce precursors for macromolecules, maintain the redox homeostasis, and function as waste management centers for various types of metabolic intermediates. Mitochondrial dysfunction has been implicated in the pathologies of a number of degenerative retinal diseases. It is well known that photoreceptors are particularly vulnerable …

Glaucoma Alters The Morphology Of Mouse Melanopsin-Containing Retinal Ganglion Cells, Kristin Keenan

Williams Honors College, Honors Research Projects

Melanopsin ganglion cells are intrinsically photosensitive ganglion cells in the mammalian retina. These cells mediate aspects of non-image forming vision to help regular circadian rhythm. Glaucoma is an eye disease involving an increase in intraocular pressure that has been linked to irregular circadian rhythm. This project will investigate the impact glaucoma has on these melanopsin ganglion cells at different pathological timepoints. This will be performed by using dissection, immunohistochemistry, and computer imaging methods to visualize, trace, and measure the cells’ morphologies in both control and glaucomatous retinas at different timepoints of disease to analyze if glaucoma has a significant effect …

Review Of Evidence For Environmental Causes Of Uveal Coloboma, Evan B Selzer, Delphine Blain, Robert B Hufnagel, Philip J Lupo, Laura E Mitchell, Brian P Brooks

Faculty, Staff and Student Publications

Uveal coloboma is a condition defined by missing ocular tissues and is a significant cause of childhood blindness. It occurs from a failure of the optic fissure to close during embryonic development and may lead to missing parts of the iris, ciliary body, retina, choroid, and optic nerve. Because there is no treatment for coloboma, efforts have focused on prevention. While several genetic causes of coloboma have been identified, little definitive research exists regarding the environmental causes of this condition. We review the current literature on environmental factors associated with coloboma in an effort to guide future research and preventative …

Structure And Dynamics Of Photoreceptor Sensory Cilia, Theodore G Wensel, Valencia L Potter, Abigail Moye, Zhixian Zhang, Michael A Robichaux

Faculty, Staff and Students Publications

The rod and cone photoreceptor cells of the vertebrate retina have highly specialized structures that enable them to carry out their function of light detection over a broad range of illumination intensities with optimized spatial and temporal resolution. Most prominent are their unusually large sensory cilia, consisting of outer segments packed with photosensitive disc membranes, a connecting cilium with many features reminiscent of the primary cilium transition zone, and a pair of centrioles forming a basal body which serves as the platform upon which the ciliary axoneme is assembled. These structures form a highway through which an enormous flux of …

Use Of Intravitreal Methotrexate Infusion In Complicated Retinal Detachment For Prevention Of Proliferative Vitreoretinopathy In A Pilot Study, Sana Jahangir, Tehmina Jahangir, Muhammad H. Ali, Qasim Lateef, Uzma Hamza, Haroon Tayyab

Section of Ophthalmology

Objective: The objective of this pilot study was to evaluate the efficacy and safety of per-operative intravitreal methotrexate (MTX) infusion during vitrectomy in patients of retinal detachment (RD) with advanced grade proliferative vitreoretinopathy (PVR).
Methods: In this prospective interventional case series, we included patients with Grade C PVR, recurrent RD, and open globe trauma. All patients underwent standard single surgeon operated 23-gauge pars plana vitrectomy (PPV) with 80mg of MTX in 1000mL of irrigation fluid. All patients were followed up after four months to assess the final status of retinal attachment and visual acuity. Ethical review board permission was sought …

Neurovascular Regulation In Diabetic Retinopathy And Emerging Therapies, Liyang Ji, Hong Tian, Keith A Webster, Wei Li

Faculty, Staff and Students Publications

Diabetic retinopathy (DR) is the leading cause of vision loss in working adults in developed countries. The disease traditionally classified as a microvascular complication of diabetes is now widely recognized as a neurovascular disorder resulting from disruption of the retinal neurovascular unit (NVU). The NVU comprising retinal neurons, glia and vascular cells coordinately regulates blood flow, vascular density and permeability to maintain homeostasis. Disturbance of the NVU during DR can lead to vision-threatening clinical manifestations. A limited number of signaling pathways have been identified for intercellular communication within the NVU, including vascular endothelial growth factor (VEGF), the master switch for …

Retinal Regeneration In A Genetic Mouse Model Of Glaucoma, Joshua Paris

Masters Theses

Glaucoma is a degenerative retinal disease characterized by progressive loss of retinal ganglion cells (RGCs). Previous studies have shown that application of a specific α7 nicotinic acetylcholine receptor agonist, PNU-282987 (PNU), onto the murine retina induces neurogenesis of numerous retinal cell types, including RGCs. The aim of this study is to characterize the short-term and long-term effects of PNU in a glaucoma model. The effects of PNU were analyzed in a DBA/2J mouse model that auto-induces a glaucoma-like condition in adulthood. These mice manifest an elevated intraocular pressure (IOP) starting at 6 months, followed by loss of RGCs. To assess …

Addressing Artificial Intelligence Bias In Retinal Diagnostics, Philippe Burlina, Neil Joshi, William Paul, Katia D Pacheco, Neil M Bressler

Faculty, Staff and Students Publications

PURPOSE: This study evaluated generative methods to potentially mitigate artificial intelligence (AI) bias when diagnosing diabetic retinopathy (DR) resulting from training data imbalance or domain generalization, which occurs when deep learning systems (DLSs) face concepts at test/inference time they were not initially trained on.

METHODS: The public domain Kaggle EyePACS dataset (88,692 fundi and 44,346 individuals, originally diverse for ethnicity) was modified by adding clinician-annotated labels and constructing an artificial scenario of data imbalance and domain generalization by disallowing training (but not testing) exemplars for images of retinas with DR warranting referral (DR-referable) from darker-skin individuals, who presumably have greater …

Diagnostic Criteria For Detection Of Retinal Nerve Fibre Layer Thickness And Neuroretinal Rim Width Abnormalities In Glaucoma, Feihui Zheng, Marco Yu, Christopher Kai-Shun Leung

Faculty, Staff and Student Publications

BACKGROUND/AIMS: Although measurements of the Bruch's membrane opening minimum rim width (BMO-MRW) and retinal nerve fibre layer thickness (RNFLT) with optical coherence tomography (OCT) have been widely adopted in the diagnostic evaluation of glaucoma, there is no consensus on the diagnostic criteria to define BMO-MRW and RNFLT abnormalities. This study investigated the sensitivities and specificities of different diagnostic criteria based on the OCT classification reports for detection of glaucoma.

METHODS: 340 eyes of 137 patients with glaucoma and 87 healthy individuals, all with axial length ≤26mm, had global and sectoral BMO-MRW and RNFLT measured with Spectralis OCT (Heidelberg Engineering). Six …

Melanopsin-Expressing Retinal Ganglion Cells In Control Vs. Glaucomatous Retinas, Edward Hamad

Williams Honors College, Honors Research Projects

Glaucoma is a common cause of vision loss worldwide and has a large scope of symptoms, ranging from pupillary reflex defects to sleep disorders. These issues can be explained partially by a recently found subtype of retinal ganglion cells that express melanopsin, denoted melanopsin-expressing retinal ganglion cells or mRGCs for short. These cells function primarily as photoreceptors in the non-image forming pathway, but can receive input from rods and cones. Since mRGCs play a role in the pupillary reflex and regulation of the sleep-wake cycle, I investigated if glaucoma leads to the degeneration of these cells in a mouse model …