Developmental Biology 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 …

Investigating The Role Of Chd7 And Sox11 In Retinal Cell Development And The Ocular Complications Of Charge Syndrome, Laura Krueger

Theses and Dissertations--Biology

Proper formation of the visual system requires the precise interaction of several embryonic cell lineages, including the neuroectoderm (forms the retina and retinal pigment epithelium), surface ectoderm (forms the lens), mesoderm and cranial neural crest cells (form the ocular blood vessels and anterior ocular structures). When this process is disrupted structural birth defects such as coloboma result, leading to pediatric visual deficits. Ocular developmental defects are often present in larger syndromic disorders. One example is CHARGE syndrome, a genetic disorder characterized by coloboma, heart defects, choanal atresia, growth retardation, genital abnormalities, and ear abnormalities. Pathogenic variants in CHD7 have been …

The Role Of Sox4 In Ocular Morphogenesis And Retinal Differentiation, Rebecca Petersen

Theses and Dissertations--Biology

Visual impairment ranges from mild forms that can be corrected with glasses to more severe cases that result in permanent loss of vision. Microphthalmia, anophthalmia, and coloboma (collectively referred to as MAC) account for 11% of cases of pediatric blindness and are a result of improper ocular morphogenesis. Retinitis Pigmentosa (RP) is a retinal degenerative disease that affects 1 in 3000 people worldwide. It is a progressive disorder that initially begins with loss of vision in low light settings due to rod photoreceptor degeneration but progresses to complete blindness upon loss of cone photoreceptors. Currently, there is no cure for …

Understanding The Effects Of Embryonic Hyperglycemia On Retinal Development And Maintenance, Kayla Titialii-Torres

Theses and Dissertations--Biology

Hundreds of millions of people are affected by diabetes worldwide. Whether they are diagnosed with prediabetes or Type I or II diabetes, there are a variety of mechanisms in the pathogenesis of diabetes. Diabetes is a disease which consists of recurring states of hyperglycemia that can be difficult to manage due to either lack of insulin production or improper utilization of insulin. While these mechanisms of action differ, complications induced by diabetes occur in both poorly regulated Type I and II. Common complications of diabetes include nerve damage, kidney damage, and eye damage. Eye damage specifically is called diabetic retinopathy …

Analysis Of Adult Neural Retina Extracellular Vesicle Release, Rna Transport And Proteomic Cargo, Jason Mighty, Jing Zhou, Alberto Benito-Martin, Sami Sauma, Samer Hanna, Onyekwere Onwumere, Cui Shi, Martin Muntzel, Moira Sauane, Michael Young, Henrik Molina, Dianne Cox, Stephen Redenti

Publications and Research

PURPOSE. Extracellular vesicles (EVs) contain RNA and protein cargo reflective of the genotype and phenotype of the releasing cell of origin. Adult neural retina EV release, RNA transfer, and proteomic cargo are the focus of this study.

METHODS. Adult wild-type mouse retinae were cultured and released EV diameters and concentrations quantified using Nanosight. Immunogold transmission electron microscopy (TEM) was used to image EV ultrastructure and marker protein localization. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to analyze retinal cell transcripts present in EVs. Super-resolution microscopy was used to image fluorescent (green) RNA and (red) lipid membrane labeled EVs, released …

Molecular Analysis Of Cone Photoreceptor Genesis From A Specific Retinal Progenitor Population, Diego F. Buenaventura

Dissertations, Theses, and Capstone Projects

There are two types of photosensitive cells of the retina that contribute to image formation: Cone photoreceptors that mediate color discrimination and rods that provide photosensitivity in low-light conditions. Given the importance of cones in high acuity and color vision, deficiencies in this cell type that result from ailments such as retinitis pigmentosa and macular degeneration can lead to a debilitating loss of vision. Currently, one of the most pressing goals in the field of retinal development is the elucidation of the gene regulatory networks (GRN) involved in inducing an undifferentiated cell into becoming a functional cone photoreceptor.

Recently, an …

Characterizing Epigenetic Regulation In The Developing Chicken Retina, Bejan Abbas Rasoul

Masters Theses, 2010-2019

The retina, the sensory neuronal tissue within the eye, is composed of three layers of neuronal cells connected by two synaptic layers lining the inside of the anterior portion of the eye. Multipotent retinal precursor cells are genetically homogeneous and differentiate into mature retinal neurons due to differential gene expression. Differences in gene expression have been correlated with epigenetic modifications such as DNA methylation. DNA methylation of upstream regulatory elements is associated with transcriptional silencing of gene expression. Years of research in retinal development has identified the numerous genes expressed during the main steps of retinal development, however, it is …

Modeling 3d Retinogenesis In Mouse Embryonic Stem Cells Following Crispr-Mediated Crx Knockdown, Pooja Prasad

Dissertations, Masters Theses, Capstones, and Culminating Projects

An emerging technology known as three-dimensional (3D) tissue engineering has allowed scientists to mimic tissues found in vivo. Previous studies indicate that it is possible to differentiate dissociated mouse embryonic stem cells (mESCs) into 3D retinal tissues in vitro (Bertacchi, 2015; Eiraku, 2012). The newly differentiated retinal tissues are said to encompass all of the major components found in retinal tissues. The generation of in vitro 3D tissues holds great potential in terms of patient-specific disease modeling. Although various diseases have been well-studied in animal models, there are limitations with regards to patient-specificity. The generation of animal models to study …

Transposon-Mediated Stable Suppression Of Gene Expression In The Developing Chick Retina, Masaru Nakamoto, Chizu Nakamoto

Biology Faculty Publications

The embryonic chick has long been a favorite model system for in vivo studies of vertebrate development. However, a major technical limitation of the chick embryo has been the lack of efficient loss-of-function approaches for analyses of gene functions. Here, we describe a methodology in which a transgene encoding artificial microRNA sequences is introduced into embryonic chick retinal cells by in ovo electroporation and integrated into the genome using the Tol2 transposon system. We show that this methodology can induce potent and stable suppression of gene expression. This technique therefore provides a rapid and robust loss-of-function approach for studies of …

Mechanics Of Early Retina And Lens Development In The Embryo, Alina Oltean

McKelvey School of Engineering Graduate Student Theses & Dissertations

Mechanical forces play an essential role in morphogenesis, the shaping of embryonic structures. This research focuses mainly on eye development, a problem that has been studied for decades using a variety of approaches. However, the mechanics of the early stages of eye formation remain incompletely understood.

The embryonic eyes begin as bilateral protrusions called optic vesicles (OVs) that grow outward from the anterior end of the brain tube. The optic vesicles contact and adhere to the overlying surface ectoderm (SE) via extracellular matrix (ECM). Then, both layers thicken in the region of contact to form the retinal and lens placodes, …

Efficient In Vitro Development Of Photoreceptors From Human Pluripotent Stem Cells, Joseph C. Reynolds

Dissertations, Masters Theses, Capstones, and Culminating Projects

Degeneration of the rod and cone photoreceptors in the human retina is among the most common causes of blindness. Replacing these damaged photoreceptors may help to restore vision. Repairing the damaged retina relies on the insertion of new, healthy cells. Embryonic stem (ES) cells and induced pluripotent stem (iPS) cells are two possible sources of photoreceptors to restore vision. Previous data shows that human ES cells and iPS cells can be differentiated into photoreceptors and transplanted into the eye to restore some vision. However, this process is inefficient, and costly. Here, we show a new method for inducing photoreceptor production …

Dual Functions For Insulinoma-Associated 1 In Retinal Development, Marie A. Forbes-Osborne

Theses and Dissertations--Biology

Proper visual system function requires tightly controlled proliferation of a pool of relatively homogeneous retinal progenitor cells, followed by the stepwise specification and differentiation of multiple distinct cell types. These retinal cells, both neuronal and glial, must be generated in the correct numbers, and the correct laminar location to permit the formation of synaptic connections between individual cell types. After synapses are made, constant signaling is required as part of normal retinal function, and to maintain cellular identity and connectivity. These processes rely on both extrinsic and intrinsic signaling, with regulation of gene expression by cascades of transcription factors having …

Cell Cycle Regulation Of Retinal Progenitors; A Role For The Nance-Horan Syndrome Protein In Retinogenesis, Paul J. Vorster

Theses and Dissertations

The Nance-Horan syndrome gene (NHS) plays a role in lens, eye and brain development. To date, the function of NHS remains unclear. Recent evidence showed that p53 isoform, Δ113p53, inhibits abnormal cell growth during organogenesis. We show that NHS is expressed in the retinas of Danio rerio and Xenopus tropicalis during key stages of retinogenesis, and that knockdown of the gene resulted in a small eye phenotype in both species. Initially, knockdown of nhsb in zebrafish had no visible defects at 24hpf. But examination of the retina at 48hpf, we see a marked difference in size compared to control embryos. …

Characterization Of Adult Zebrafish Retinal Regeneration Following Two Different Damage Models, Jennifer Lee Thomas

Wayne State University Dissertations

Unlike mammals, zebrafish can regenerate all of their retinal neurons through Müller glial cells, which respond to retinal damage by re-entering the cell cycle to create clusters of progenitor cells. The progenitors continue to proliferate as they migrate to the site of damage, where they ultimately differentiate into new retinal neurons. In contrast, Müller glia of the mammalian retina respond to injury with reactive gliosis, which if persistent, can lead to loss of Müller cell function and devastating vision loss. Despite this, multiple lines of evidence suggest that mammalian Müller glial cells possess a latent ability to regenerate retinal neurons. …

Loss-Of-Function Analysis Of Epha Receptors In Retinotectal Mapping, David Feldheim, Masaru Nakamoto, Miriam Osterfield, Nicholas Gale, Thomas Dechiara, Rajat Rohatgi, George Yancopoulos, John Flanagan

Biology Faculty Publications

EphA tyrosine kinases are thought to act as topographically specific receptors in the well-characterized projection map from the retina to the tectum. Here, we describe a loss-of-function analysis of EphA receptors in retinotectal mapping. Expressing patches of a cytoplasmically truncated EphA3 receptor in chick retina caused temporal axons to have reduced responsiveness to posterior tectal repellent activity in vitro  and to shift more posteriorly within the map in vivo . A gene disruption of mouse EphA5, replacing the intracellular domain with beta-galactosidase, reduced in vitro  responsiveness of temporal axons to posterior target membranes. It also caused map abnormalities in vivo …