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Nitasha R Phatak, Dorota L Stankowska, Raghu R Krishnamoorthy
PURPOSE: Brn3b is a class IV POU domain transcription factor that plays an important role in the development of retinal ganglion cells (RGCs), RGC survival, and particularly axon growth and pathfinding. Our previous study demonstrated that recombinant adenoassociated virus serotype 2 (rAAV-2)-mediated overexpression of Brn3b in RGCs promoted neuroprotection in a rodent model of glaucoma. However, the mechanisms underlying neuroprotection of RGCs in rats overexpressing Brn3b in animal models of glaucoma remain largely unknown...
2016: Molecular Vision
Miruna Georgiana Ghinia, Elena Novelli, Szilard Sajgo, Tudor Constantin Badea, Enrica Strettoi
Ganglion cells (GCs), the retinal output neurons, receive synaptic inputs from bipolar and amacrine cells in the inner plexiform layer (IPL) and send information to the brain nuclei via the optic nerve. Although GCs constitute less than 1% of the total retinal cells, they occur in numerous types and are the first neurons formed during retinal development. Using Brn3a and Brn3b mutant mice in which the alkaline phosphatase gene was knocked-in (Badea et al., 2009a; Badea and Nathans, 2011), we studied the general effects upon gene removal on the retinal neuropil together with the consequences of lack of development of large numbers of GCs onto the remaining retinal neurons of the same class...
July 8, 2016: Journal of Comparative Neurology
Varsha Jain, Ipsit Srivastava, Shriya Palchaudhuri, Manvi Goel, Sumit K Sinha-Mahapatra, Narender K Dhingra
Pupillary light reflex (PLR) is an important clinical tool to assess the integrity of visual pathways. The available evidence suggests that melanopsin-expressing retinal ganglion cells (mRGCs) mediate PLR-driven by the classical photoreceptors (rods and cones) at low irradiances and by melanopsin activation at high irradiances. However, genetic or pharmacological elimination of melanopsin does not completely abolish PLR at high irradiances, raising the possibility that classical photoreceptors may have a role even at high irradiances...
2016: PloS One
Fei Deng, Mengfei Chen, Ying Liu, Huiling Hu, Yunfan Xiong, Chaochao Xu, Yuchun Liu, Kangjun Li, Jing Zhuang, Jian Ge
PURPOSE: As an alternative and desirable approach for regenerative medicine, human induced pluripotent stem cell (hiPSC) technology raises the possibility of developing patient-tailored cell therapies to treat intractable degenerative diseases in the future. This study was undertaken to guide human Tenon's capsule fibroblasts-derived iPSCs (TiPSCs) to differentiate along the retinal ganglion cell (RGC) lineage, aiming at producing appropriate cellular material for RGC regeneration. METHODS: By mimicking RGC genesis, we deliberately administered the whole differentiation process and directed the stage-specific differentiation of human TiPSCs toward an RGC fate via manipulation of the retinal inducers (DKK1+Noggin+Lefty A) alongside master gene (Atoh7) sequentially...
2016: Molecular Vision
Chunsheng Qu, Dandan Bian, Xue Li, Jian Xiao, Chunping Wu, Yue Li, Tian Jiang, Xiangtian Zhou, Jia Qu, Jie-Guang Chen
Retinal ganglion cells (RGCs) are projection neurons in the neural retina that relay visual information from the environment to the central nervous system. The early expression of MATH5 endows the post-mitotic precursors with RGC competence and leads to the activation ofBrn3bthat marks committed RGCs. Nevertheless, this fate commitment process and, specifically, regulation ofBrn3bremain elusive. To explore the molecular mechanisms underlying RGC generation in the mouse retina, we analyzed the expression and function of Fez family zinc finger 2 (FEZF2), a transcription factor critical for the development of projection neurons in the cerebral cortex...
April 1, 2016: Journal of Biological Chemistry
K A Fernandes, S J Bloomsburg, C J Miller, S A Billingslea, M M Merrill, R W Burgess, R T Libby, P G Fuerst
The Down syndrome cell adhesion molecule gene (Dscam) is required for normal dendrite patterning and promotes developmental cell death in the mouse retina. Loss-of-function studies indicate that Dscam is required for refinement of retinal ganglion cell (RGC) axons in the lateral geniculate nucleus, and in this study we report and describe a requirement for Dscam in the maintenance of RGC axon projections within the retina. Mouse Dscam loss of function phenotypes related to retinal ganglion cell axon outgrowth and targeting have not been previously reported, despite the abundance of axon phenotypes reported in Drosophila Dscam1 loss and gain of function models...
March 2016: Molecular and Cellular Neurosciences
Szilard Sajgo, Seid Ali, Octavian Popescu, Tudor Constantin Badea
During development, transcription factor combinatorial codes define a large variety of morphologically and physiologically distinct neurons. Such a combinatorial code has been proposed for the differentiation of projection neurons of the somatic and visceral components of cranial nerves. It is possible that individual neuronal cell types are not specified by unique transcription factors but rather emerge through the intersection of their expression domains. Brn3a, Brn3b, and Brn3c, in combination with each other and/or transcription factors of other families, can define subgroups of retinal ganglion cells (RGC), spiral and vestibular ganglia, inner ear and vestibular hair cell neurons in the vestibuloacoustic system, and groups of somatosensory neurons in the dorsal root ganglia...
April 1, 2016: Journal of Comparative Neurology
Ratnesh K Singh, Ramya K Mallela, Pamela K Cornuet, Aaron N Reifler, Andrew P Chervenak, Michael D West, Kwoon Y Wong, Igor O Nasonkin
Stem cell-based therapy of retinal degenerative conditions is a promising modality to treat blindness, but requires new strategies to improve the number of functionally integrating cells. Grafting semidifferentiated retinal tissue rather than progenitors allows preservation of tissue structure and connectivity in retinal grafts, mandatory for vision restoration. Using human embryonic stem cells (hESCs), we derived retinal tissue growing in adherent conditions consisting of conjoined neural retina and retinal pigment epithelial (RPE) cells and evaluated cell fate determination and maturation in this tissue...
December 1, 2015: Stem Cells and Development
Dana Morzaev, James D Nicholson, Tomm Caspi, Shirel Weiss, Edith Hochhauser, Nitza Goldenberg-Cohen
BACKGROUND: This study aims to investigate the role of the inflammatory response following optic nerve crush (ONC) in knockout mice for the toll-like receptor-4 gene (TLR4-/-) compared to wild-type (WT) mice. METHODS: ONC was induced in TLR4-/- and C57BL6 WT mice. Histological sections of the retina and optic nerve were analysed on days 1, 3 or 21 after injury. Molecular analysis with real-time quantitative polymerase chain reaction was used to study the expression of CD45, tumour necrosis-alpha (TNF-α) and glial fibrillary acidic protein, as well as retinal ganglion cell (RGC) markers THY-1 and Brn3b...
September 2015: Clinical & Experimental Ophthalmology
Taku Tanaka, Tadashi Yokoi, Fuminobu Tamalu, Shu-Ichi Watanabe, Sachiko Nishina, Noriyuki Azuma
We generated self-induced retinal ganglion cells (RGCs) with functional axons from human induced pluripotent stem cells. After development of the optic vesicle from the induced stem cell embryoid body in three-dimensional culture, conversion to two-dimensional culture, achieved by supplementation with BDNF, resulted in differentiation of RGCs at a rate of nearly 90% as indicated by a marginal subregion of an extruded clump of cells, suggesting the formation of an optic vesicle. Axons extended radially from the margin of the clump...
2015: Scientific Reports
Dorota L Stankowska, Alena Z Minton, Margaret A Rutledge, Brett H Mueller, Nitasha R Phatak, Shaoqing He, Hai-Ying Ma, Michael J Forster, Thomas Yorio, Raghu R Krishnamoorthy
PURPOSE: Glaucoma is an optic neuropathy commonly associated with elevated intraocular pressure (IOP), leading to optic nerve head (ONH) cupping, axon loss, and apoptosis of retinal ganglion cells (RGCs), which could ultimately result in blindness. Brn3b is a class-4 POU domain transcription factor that plays a key role in RGC development, axon outgrowth, and pathfinding. Previous studies suggest that a decrease in Brn3b levels occurs in animal models of glaucoma. The goal of this study was to determine if adeno-associated virus (AAV)-directed overexpression of the Brn3b protein could have neuroprotective effects following elevated IOP-mediated neurodegeneration...
February 2015: Investigative Ophthalmology & Visual Science
Masayoshi Yukita, Shigeki Machida, Koji M Nishiguchi, Satoru Tsuda, Yu Yokoyama, Masayuki Yasuda, Kazuichi Maruyama, Toru Nakazawa
PURPOSE: Optic nerve crush (ONC) and subsequent axonal damage can be used in rodents to study the mechanism of retinal ganglion cell (RGC) degeneration. Here, we examined electroretinograms (ERGs) in post-ONC mice to investigate changes in the positive scotopic threshold response (pSTR). We then compared these changes with molecular and morphological changes to identify early objective biomarkers of RGC dysfunction. METHODS: Fifty 12-week-old C57BL/6 mice were included...
April 2015: Documenta Ophthalmologica. Advances in Ophthalmology
Reza Roozafzoon, Alireza Lashay, Mohammad Vasei, Jafar Ai, Ahad Khoshzaban, Saeed Heidari Keshel, Zahra Barabadi, Hoda Bahrami
The loss of retinal ganglion cells (RGCs) in majority of retinal degenerative diseases is the first seen pathological event. A lot of studies aim to discover suitable cell sources to replace lost and damaged RGCs. Among them dental pulp stem cells (DPSCs) have a great potential of differentiating into neuronal lineages as well as RGCs. Moreover, three-dimensional (3D) networks and its distribution for growing and differentiation of stem cells as much as possible mimic to native tissue holds great potential in retinal tissue engineering...
February 6, 2015: Biochemical and Biophysical Research Communications
Francisco M Nadal-Nicolás, Manuel Salinas-Navarro, Manuel Jiménez-López, Paloma Sobrado-Calvo, María P Villegas-Pérez, Manuel Vidal-Sanz, Marta Agudo-Barriuso
We have studied in parallel the population of displaced retinal ganglion cells (dRGCs) and normally placed (orthotopic RGCs, oRGCs) in albino and pigmented rats. Using retrograde tracing from the optic nerve, from both superior colliculi (SC) or from the ipsilateral SC in conjunction with Brn3 and melanopsin immunodetection, we report for the first time their total number and topography as well as the number and distribution of those dRGCs and oRGCs that project ipsi- or contralaterally and/or that express any of the three Brn3 isoforms or melanopsin...
2014: Frontiers in Neuroanatomy
Budd A Tucker, Frances Solivan-Timpe, Ben R Roos, Kristin R Anfinson, Alan L Robin, Luke A Wiley, Robert F Mullins, John H Fingert
Duplication of theTBK1 gene causes normal tension glaucoma (NTG); however the mechanism by which this copy number variation leads to retinal ganglion cell death is poorly understood. The ability to use skin-derived induced pluripotent stem cells (iPSCs) to investigate the function or dysfunction of a mutant gene product in inaccessible tissues such as the retina now provides us with the ability to interrogate disease pathophysiology in vitro. iPSCs were generated from dermal fibroblasts obtained from a patient with TBK1-associated NTG, via viral transduction of the transcription factors OCT4, SOX2, KLF4, and c-MYC...
January 25, 2014: Journal of Stem Cell Research & Therapy
Vazhanthodi A Rasheed, Sreekumaran Sreekanth, Sivadasan B Dhanesh, Mundackal S Divya, Thulasi S Divya, Palakkottu K Akhila, Chandramohan Subashini, Krishnankutty Chandrika Sivakumar, Ani V Das, Jackson James
Differential regulation of Brn3b is essential for the Retinal Ganglion Cell (RGC) development in the two phases of retinal histogenesis. This biphasic Brn3b regulation is required first, during early retinal histogenesis for RGC fate specification and secondly, during late histogenesis, where Brn3b is needed for RGC axon guidance and survival. Here, we have looked into how the regulation of Brn3b at these two stages happens. We identified two miRNAs, miR-23a and miR-374, as regulators of Brn3b expression, during the early stage of RGC development...
December 2014: Developmental Neurobiology
Szilard Sajgo, Miruna Georgiana Ghinia, Melody Shi, Pinghu Liu, Lijin Dong, Nadia Parmhans, Octavian Popescu, Tudor Constantin Badea
BACKGROUND: Genetic targeting methods have greatly advanced our understanding of many of the 20 Retinal Ganglion Cell (RGC) types conveying visual information from the eyes to the brain. However, the complexity and partial overlap of gene expression patterns in RGCs call for genetic intersectional or sparse labeling strategies. Loci carrying the Cre recombinase in conjunction with conditional knock-out, reporter or other genetic tools can be used for targeted cell type ablation and functional manipulation of specific cell populations...
2014: PloS One
Hamidreza Riazifar, Yousheng Jia, Jing Chen, Gary Lynch, Taosheng Huang
The loss of retinal ganglion cells (RGCs) is the primary pathological change for many retinal degenerative diseases. Although there is currently no effective treatment for this group of diseases, cell transplantation to replace lost RGCs holds great potential. However, for the development of cell replacement therapy, better understanding of the molecular details involved in differentiating stem cells into RGCs is essential. In this study, a novel, stepwise chemical protocol is described for the differentiation of human embryonic stem cells and induced pluripotent stem cells into functional RGCs...
April 2014: Stem Cells Translational Medicine
Marek Pacal, Rod Bremner
BACKGROUND: Despite the disease relevance, understanding of human retinal development lags behind that of other species. We compared the kinetics of gene silencing or induction during ganglion cell development in human and murine retina. RESULTS: Induction of POU4F2 (BRN3B) marks ganglion cell commitment, and we detected this factor in S-phase progenitors that had already silenced Cyclin D1 and VSX2 (CHX10). This feature was conserved in human and mouse retina, and the fraction of Pou4f2+ murine progenitors labeled with a 30 min pulse of BrdU matched the fraction of ganglion cells predicted to be born in a half-hour period...
May 2014: Developmental Dynamics: An Official Publication of the American Association of Anatomists
Ma'ayan Semo, Carlos Gias, Ahmad Ahmado, Anthony Vugler
Maintenance of pupillary constriction in light-adapted rodents has traditionally been thought to involve a reflex between retina, brain and iris, with recent work identifying the melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs) as the major conduits for retinal input to the brain. There is also a less well-understood phenomenon whereby the iris of some mammals, including mice, will constrict to light when either the eye, or the iris itself is physically isolated from the brain...
February 2014: Experimental Eye Research
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