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https://www.readbyqxmd.com/read/27917311/rock-inhibition-promotes-attachment-proliferation-and-wound-closure-in-human-embryonic-stem-cell-derived-retinal-pigmented-epithelium
#1
Roxanne H Croze, William J Thi, Dennis O Clegg
PURPOSE: Nonexudative (dry) age-related macular degeneration (AMD), a leading cause of blindness in the elderly, is associated with the loss of retinal pigmented epithelium (RPE) cells and the development of geographic atrophy, which are areas devoid of RPE cells and photoreceptors. One possible treatment option would be to stimulate RPE attachment and proliferation to replace dying/dysfunctional RPE and bring about wound repair. Clinical trials are underway testing injections of RPE cells derived from pluripotent stem cells to determine their safety and efficacy in treating AMD...
November 2016: Translational Vision Science & Technology
https://www.readbyqxmd.com/read/27916682/adaptive-optics-optical-coherence-tomography-in-glaucoma
#2
REVIEW
Zachary M Dong, Gadi Wollstein, Bo Wang, Joel S Schuman
Since the introduction of commercial optical coherence tomography (OCT) systems, the ophthalmic imaging modality has rapidly expanded and it has since changed the paradigm of visualization of the retina and revolutionized the management and diagnosis of neuro-retinal diseases, including glaucoma. OCT remains a dynamic and evolving imaging modality, growing from time-domain OCT to the improved spectral-domain OCT, adapting novel image analysis and processing methods, and onto the newer swept-source OCT and the implementation of adaptive optics (AO) into OCT...
December 1, 2016: Progress in Retinal and Eye Research
https://www.readbyqxmd.com/read/27914990/presence-of-melanopsin-in-human-crystalline-lens-epithelial-cells-and-its-role-in-melatonin-synthesis
#3
Hanan Awad Alkozi, Xiaoyu Wang, Maria Jesus Perez de Lara, Jesus Pintor
Melanopsin is a non-image forming photoreceptor known to be present in the retina and it is considered to have light regulated tasks among other functions. In the present work, melanopsin presence in human lens epithelial cells as well as in human lens tissue is described for the first time. Moreover, studying the concentration of melatonin and its synthesising enzyme AANAT proved a clear link between melanopsin activation and the suppression of melatonin synthesis. Melanopsin sensitivity to specific wavelength (465-480 nm, blue) was confirmed after making temporal studies incubating lens epithelial cells under light, red, green, blue and total darkness for 2, 4, 8, 12 h and analysing the concentration of both melatonin and its synthesising enzyme AANAT, discovering that melatonin levels after submitting cells to total darkness are significantly higher to ones submitted to white or specifically blue light (***p < 0...
November 30, 2016: Experimental Eye Research
https://www.readbyqxmd.com/read/27911923/morphology-and-hydraulic-architecture-of-vitis-vinifera-l-cv-syrah-and-torront%C3%A3-s-riojano-plants-are-unaffected-by-variations-in-red-to-far-red-ratio
#4
Carina Verónica González, María Florencia Jofré, Hernán F Vila, Markus Stoffel, Rubén Bottini, Carla Valeria Giordano
Plants have evolved an array of specific photoreceptors to acclimate to the light environment. By sensing light signals, photoreceptors modulate plant morphology, carbon- and water-physiology, crop yield and quality of harvestable organs, among other responses. Many cultural practices and crop management decisions alter light quantity and quality perceived by plants cultivated in the field. Under full sunlight, phytochromes perceive high red to far red ratios (R:FR; 1.1), whereas overhead or lateral low R:FR (below 1...
2016: PloS One
https://www.readbyqxmd.com/read/27911706/using-induced-pluripotent-stem-cells-to-understand-retinal-ciliopathy-disease-mechanisms-and-develop-therapies
#5
REVIEW
David A Parfitt, Amelia Lane, Conor Ramsden, Katarina Jovanovic, Peter J Coffey, Alison J Hardcastle, Michael E Cheetham
The photoreceptor cells in the retina have a highly specialised sensory cilium, the outer segment (OS), which is important for detecting light. Mutations in cilia-related genes often result in retinal degeneration. The ability to reprogramme human cells into induced pluripotent stem cells and then differentiate them into a wide range of different cell types has revolutionised our ability to study human disease. To date, however, the challenge of producing fully differentiated photoreceptors in vitro has limited the application of this technology in studying retinal degeneration...
October 15, 2016: Biochemical Society Transactions
https://www.readbyqxmd.com/read/27911705/disease-mechanisms-of-x-linked-retinitis-pigmentosa-due-to-rp2-and-rpgr-mutations
#6
REVIEW
Rodanthi Lyraki, Roly Megaw, Toby Hurd
Photoreceptor degeneration is the prominent characteristic of retinitis pigmentosa (RP), a heterogeneous group of inherited retinal dystrophies resulting in blindness. Although abnormalities in many pathways can cause photoreceptor degeneration, one of the most important causes is defective protein transport through the connecting cilium, the structure that connects the biosynthetic inner segment with the photosensitive outer segment of the photoreceptors. The majority of patients with X-linked RP have mutations in the retinitis pigmentosa GTPase regulator (RPGR) or RP2 genes, the protein products of which are both components of the connecting cilium and associated with distinct mechanisms of protein delivery to the outer segment...
October 15, 2016: Biochemical Society Transactions
https://www.readbyqxmd.com/read/27911422/-diagnostic-potential-of-optical-coherence-tomography-for-small-choroidal-melanomas
#7
A F Brovkina, A S Stoyukhina, I V Musatkina
AIM: To investigate the sequence of OCT manifestations in choroidal melanoma (CM) with account to its growth. MATERIAL AND METHODS: A total of 28 CM patients were examined. Of them, 18 patients with early CM, 10 - with medium-sized CM. The mean patient age at diagnosis was 60.54±5.31 years. Tumor location was macular (15 eyes) or perimacular (13 eyes), its prominence varied from 0.98 to 4.9 mm and basal diameter - from 5.08 to 18.9 mm. Additionally to OCT, tumor autofluorescence was studied in all cases...
2016: Vestnik Oftalmologii
https://www.readbyqxmd.com/read/27909686/lipofuscins-prepared-by-modification-of-photoreceptor-cells-via-glycation-or-lipid-peroxidation-show-the-similar-phototoxicity
#8
Alexander Dontsov, Anna Koromyslova, Mikhail Ostrovsky, Natalia Sakina
AIM: To investigate the effect of two ways of lipofuscin production (lipid peroxidation and glycation) on lipofuscin fluorescence characteristics and phototoxicity and to compare them with the properties of natural lipofuscin. METHODS: Model lipofuscins were prepared on the basis of bovine photoreceptor outer segments (POS) with bisretinoid A2E addition. One set of samples was prepared from POS modified by lipid peroxidation, while another set from POS modified by glycation with fructose...
November 20, 2016: World Journal of Experimental Medicine
https://www.readbyqxmd.com/read/27906179/pink1-dependent-phosphorylation-of-pink1-and-parkin-is-essential-for-mitochondrial-quality-control
#9
Na Zhuang, Lin Li, She Chen, Tao Wang
Mitochondrial dysfunction has been linked to the pathogenesis of a large number of inherited diseases in humans, including Parkinson's disease, the second most common neurodegenerative disorder. The Parkinson's disease genes pink1 and parkin, which encode a mitochondrially targeted protein kinase, and an E3 ubiquitin ligase, respectively, participate in a key mitochondrial quality-control pathway that eliminates damaged mitochondria. In the current study, we established an in vivo PINK1/Parkin-induced photoreceptor neuron degeneration model in Drosophila with the aim of dissecting the PINK1/Parkin pathway in detail...
December 1, 2016: Cell Death & Disease
https://www.readbyqxmd.com/read/27903903/novel-roles-of-hp1a-and-mcm10-in-dna-replication-genome-maintenance-and-photoreceptor-cell-differentiation
#10
Nicole Vo, Dang Ngoc Anh Suong, Natsuki Yoshino, Hideki Yoshida, Sue Cotterill, Masamitsu Yamaguchi
Both Mcm10 and HP1a are known to be required for DNA replication. However, underlying mechanism is not clarified yet especially for HP1. Knockdown of both HP1a and Mcm10 genes inhibited the progression of S phase in Drosophila eye imaginal discs. Proximity Ligation Assay (PLA) demonstrated that HP1a is in close proximity to DNA replication proteins including Mcm10, RFC140 and DNA polymerase ϵ 255 kDa subunit in S-phase. This was further confirmed by co-immunoprecipitation assay. The PLA signals between Mcm10 and HP1a are specifically observed in the mitotic cycling cells, but not in the endocycling cells...
November 29, 2016: Nucleic Acids Research
https://www.readbyqxmd.com/read/27901468/loss-of-frataxin-activates-the-iron-sphingolipid-pdk1-mef2-pathway-in-mammals
#11
Kuchuan Chen, Tammy Szu-Yu Ho, Guang Lin, Kai Li Tan, Matthew N Rasband, Hugo J Bellen
Friedreich's ataxia (FRDA) is an autosomal recessive neurodegenerative disease caused by mutations in Frataxin (FXN). Loss of FXN causes impaired mitochondrial function and iron homeostasis. An elevated production of reactive oxygen species (ROS) was previously proposed to contribute to the pathogenesis of FRDA. We recently showed that loss of frataxin homolog (fh), a Drosophila homolog of FXN, causes a ROS independent neurodegeneration in flies (Chen et al., 2016). In fh mutants, iron accumulation in the nervous system enhances the synthesis of sphingolipids, which in turn activates 3-phosphoinositide dependent protein kinase-1 (Pdk1) and myocyte enhancer factor-2 (Mef2) to trigger neurodegeneration of adult photoreceptors...
November 30, 2016: ELife
https://www.readbyqxmd.com/read/27901172/conformational-states-of-hamp-domains-interacting-with-sensory-rhodopsin-membrane-systems-an-integrated-all-atom-and-coarse-grained-molecular-dynamics-simulation-approach
#12
Bikash Ranjan Sahoo, Toshimichi Fujiwara
Understanding the downstream signaling mechanism of sensory rhodopsin and its cognate transducer complex (srII-htrII) has long been a challenge in the field of photoreceptor research. Here, an integration of all-atom and coarse-grained (CG) molecular dynamics (MD) simulations in different srII-htrII complex states is carried out. It is shown that the cytoplasmic four-helix HAMP dimer gives rise to a gear-box model interaction with discrete hydrophobic packing in Natronomonas pharaonis (Np). Structural analysis in all-atom and CG-MD reveals a stable conformational state in the physiological environment (323 K and 1...
November 30, 2016: Molecular BioSystems
https://www.readbyqxmd.com/read/27901042/transplanted-photoreceptor-precursors-transfer-proteins-to-host-photoreceptors-by-a-mechanism-of-cytoplasmic-fusion
#13
Mandeep S Singh, Jasmin Balmer, Alun R Barnard, Sher A Aslam, Daniela Moralli, Catherine M Green, Alona Barnea-Cramer, Isabel Duncan, Robert E MacLaren
Photoreceptor transplantation is a potential future treatment for blindness caused by retinal degeneration. Photoreceptor transplantation restores visual responses in end-stage retinal degeneration, but has also been assessed in non-degenerate retinas. In the latter scenario, subretinal transplantation places donor cells beneath an intact host outer nuclear layer (ONL) containing host photoreceptors. Here we show that host cells are labelled with the donor marker through cytoplasmic transfer-94±4.1% of apparently well-integrated donor cells containing both donor and host markers...
November 30, 2016: Nature Communications
https://www.readbyqxmd.com/read/27900566/autophagy-regulates-death-of-retinal-pigment-epithelium-cells-in-age-related-macular-degeneration
#14
REVIEW
Kai Kaarniranta, Paulina Tokarz, Ali Koskela, Jussi Paterno, Janusz Blasiak
Age-related macular degeneration (AMD) is an eye disease underlined by the degradation of retinal pigment epithelium (RPE) cells, photoreceptors, and choriocapillares, but the exact mechanism of cell death in AMD is not completely clear. This mechanism is important for prevention of and therapeutic intervention in AMD, which is a hardly curable disease. Present reports suggest that both apoptosis and pyroptosis (cell death dependent on caspase-1) as well as necroptosis (regulated necrosis dependent on the proteins RIPK3 and MLKL, caspase-independent) can be involved in the AMD-related death of RPE cells...
November 29, 2016: Cell Biology and Toxicology
https://www.readbyqxmd.com/read/27899366/optical-coherence-tomography-angiography-of-foveal-hypoplasia
#15
Kaivon Pakzad-Vaezi, Pearse Keane, João Nobre Cardoso, Catherine Egan, Adnan Tufail
AIMS: To discuss foveal development in the context of detailed retinal vasculature imaging in foveal hypoplasia using optical coherence tomography angiography. METHODS: In this case series, the optical coherence tomography angiography results of four patients with idiopathic foveal hypoplasia and two patients with foveal hypoplasia secondary to oculocutaneous albinism are presented. RESULTS: Cases with intact visual acuity demonstrated lower grades of foveal hypoplasia on optical coherence tomography, while those with poor vision demonstrated high grades of foveal hypoplasia...
November 29, 2016: British Journal of Ophthalmology
https://www.readbyqxmd.com/read/27896899/characterization-of-a-novel-form-of-progressive-retinal-atrophy-in-whippet-dogs-a-clinical-electroretinographic-and-breeding-study
#16
André Tavares Somma, Juan Carlos Duque Moreno, Mario Teruo Sato, Blanche Dreher Rodrigues, Marianna Bacellar-Galdino, Laurence Mireille Occelli, Simon Michael Petersen-Jones, Fabiano Montiani-Ferreira
OBJECTIVE: To describe a form of progressive retinal atrophy (PRA) in Whippets including clinical, electroretinographic, optical coherence tomographic changes and pedigree analysis. ANIMALS STUDIED: Client-owned Whippet dogs (n = 51) living in Brazil. PROCEDURES: All animals were submitted for routine ophthalmic screening for presumed inherited ocular disease, which included the following: visual tests, such as obstacle course tests, in scotopic and photopic conditions, cotton ball test, dazzle reflex, ocular fundus evaluation by indirect ophthalmoscopy followed by fundus photography...
November 29, 2016: Veterinary Ophthalmology
https://www.readbyqxmd.com/read/27895995/photoreceptor-disc-shedding-in-the-living-human-eye
#17
Omer P Kocaoglu, Zhuolin Liu, Furu Zhang, Kazuhiro Kurokawa, Ravi S Jonnal, Donald T Miller
Cone photoreceptors undergo a daily cycle of renewal and shedding of membranous discs in their outer segments (OS), the portion responsible for light capture. These physiological processes are fundamental to maintaining photoreceptor health, and their dysfunction is associated with numerous retinal diseases. While both processes have been extensively studied in animal models and postmortem eyes, little is known about them in the living eye, in particular human. In this study, we report discovery of the optical signature associated with disc shedding using a method based on adaptive optics optical coherence tomography (AO-OCT) in conjunction with post-processing methods to track and monitor individual cone cells in 4D...
November 1, 2016: Biomedical Optics Express
https://www.readbyqxmd.com/read/27895654/a-comprehensive-phylogeny-reveals-functional-conservation-of-the-uv-b-photoreceptor-uvr8-from-green-algae-to-higher-plants
#18
María B Fernández, Vanesa Tossi, Lorenzo Lamattina, Raúl Cassia
Ultraviolet-B (UV-B) is present in sunlight (280-315 nm) and has diverse effects on living organisms. Low fluence rate of exposure induces a specific photomorphogenic response regulated by the UV-B response locus 8 (UVR8) receptor. UVR8 was first described in Arabidopsis thaliana. In the absence of stimuli it is located in the cytoplasm as a homodimer. However, upon UV-B irradiation, it switches to a monomer and interacts with the ubiquitin ligase E3 COP1 via the UVR8 β-propeller domain and the VP core. This induces the expression of the transcription factor HY5 leading to changes in the expression of genes associated with UV-B acclimation and stress tolerance...
2016: Frontiers in Plant Science
https://www.readbyqxmd.com/read/27894240/sumoylation-regulation-of-retina-development-and-functions
#19
L Zhang, D W-C Li
The structure and developmental mechanisms of vertebrate retina are highly conserved. One of the most distinctive events during retinogenesis is the temporally and spatially generation of seven types of retinal cells from the multipotent retinal progenitor cells. The importance and prevalence of SUMOylation in regulation of this process through modulation of gene expression and protein function diversity have been increasingly appreciated. Here, we review the biological significance of SUMOylation in retina development, examine how SUMOylation balances the proliferation and cell cycle exit of retinal progenitor cells, and finally discuss the molecular mechanisms mediating the specification of different retina neurons and photoreceptors through modulation of various transcription factors...
November 28, 2016: Current Molecular Medicine
https://www.readbyqxmd.com/read/27893887/retinal-neurodegeneration-in-diabetic-patients-without-diabetic-retinopathy
#20
Joana Tavares Ferreira, Marta Alves, Arnaldo Dias-Santos, Lívio Costa, Bruno Oliveira Santos, João Paulo Cunha, Ana Luísa Papoila, Luís Abegão Pinto
Purpose: To compare the thickness of all retinal layers between a nondiabetic group and diabetic patients without diabetic retinopathy (DR). Methods: Cross-sectional study, in which all subjects underwent an ophthalmic examination including optical coherence tomography. After automatic retinal segmentation, each retinal layer thickness (eight separate layers and overall thickness) was calculated in all nine Early Treatment Diabetic Retinopathy Study (ETDRS) areas...
November 1, 2016: Investigative Ophthalmology & Visual Science
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