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Biological Signals 1997Recent progress in research on retinal circadian rhythmicity is reviewed. Important advances include the discovery that circadian oscillators are present in the retinas... (Review)
Review
Recent progress in research on retinal circadian rhythmicity is reviewed. Important advances include the discovery that circadian oscillators are present in the retinas of diverse vertebrate species, and evidence that circadian rhythmicity is generated by the photoreceptor cells. Research on the cellular and molecular mechanisms of photoreceptor circadian rhythms has revealed that expression of a subset of genes associated with photoreception, melatonin synthesis and transcriptional control are regulated by a circadian oscillator. Finally, it has been found that cAMP mimics darkness in resetting the phase of the retinal photoreceptor circadian oscillator, suggesting that it may be a component of a transduction pathway for entrainment of the oscillator.
Topics: Animals; Biological Clocks; Circadian Rhythm; Humans; Photoreceptor Cells
PubMed: 9500656
DOI: 10.1159/000109129 -
Development, Growth & Differentiation Sep 2018Blindness caused by the disconnection between photoreceptor cells and the brain can be cured by restoring this connection through the transplantation of retinal...
Blindness caused by the disconnection between photoreceptor cells and the brain can be cured by restoring this connection through the transplantation of retinal precursor neurons. However, even after transplanting these cells, it is still unclear how to guide the axons over the long distance from the retina to the brain. To establish a method of guiding the axons of transplanted neurons, we used the Drosophila visual system. By testing different conditions, including the dissociation and preincubation length, we have successfully established a method to transplant photoreceptor precursor cells isolated from the developing eye discs of third-instar larvae into the adult retina. Moreover, we overexpressed N-cadherin (CadN) in the transplant, since it is known to be broadly expressed in the optic lobe well after developmental stages, continuing through adult stages. We found that promoting the cell adhesive properties using CadN enhances the axonal length of the grafted photoreceptor neurons and therefore is useful for future transplantation. We tested the overexpression of a CadN::Frazzled chimeric receptor and found that there was no difference in axonal length from our wild-type transplants, suggesting that the intracellular domain of CadN is necessary for axonal elongation. Altogether, using the Drosophila visual system, we have established an excellent platform for exploring the molecules required for proper axon extension of transplanted neuronal cells. Future studies building from this platform will be useful for regenerative therapy of the human nervous system based on transplantation.
Topics: Animals; Drosophila; Photoreceptor Cells; Retina
PubMed: 29989152
DOI: 10.1111/dgd.12545 -
Current Drug Targets 2020Photoreceptor loss is a major cause of blindness around the world. Stem cell therapy offers a new strategy in retina degenerative disease. Retinal progenitors can be... (Review)
Review
Photoreceptor loss is a major cause of blindness around the world. Stem cell therapy offers a new strategy in retina degenerative disease. Retinal progenitors can be derived from embryonic stem cells (ESC) in vitro, but cannot be processed to a mature state. In addition, the adult recipient retina presents a very different environment than the photoreceptor precursor donor. It seems that modulation of the recipient environment by ectopic development regulated growth factors for transplanted cells could generate efficient putative photoreceptors. The purpose of this review article was to investigate the signaling pathway of growth factors including: insulin-like growth factors (IGFs), fibroblast growth factors (FGF), Nerve growth factor (NGF), Brain-derived neurotrophic factor (BDNF), Taurin and Retinoic acid (RA) involved in the differentiation of neuroretina cell, like; photoreceptor and retinal progenitor cells. Given the results available in the related literature, the differentiation efficacy of ESCs toward the photoreceptor and retinal neurons and the important role of growth factors in activating signaling pathways such as Akt, Ras/Raf1/ and ERKs also inhibit the ASK1/JNK apoptosis pathway. Manipulating differentiated culture, growth factors can influence photoreceptor transplantation efficiency in retinal degenerative disease.
Topics: Animals; Cell Differentiation; Humans; Intercellular Signaling Peptides and Proteins; Photoreceptor Cells; Regeneration; Retina; Stem Cells; Vision Disorders
PubMed: 31755378
DOI: 10.2174/1389450120666191121103831 -
Reviews of Physiology, Biochemistry and... 1994
Review
Topics: Adaptation, Physiological; Animals; Calcium; Cyclic GMP; Photoreceptor Cells; Signal Transduction
PubMed: 7984873
DOI: 10.1007/BFb0030910 -
Current Opinion in Neurobiology Aug 1994Vertebrate and invertebrate photoreceptors respond with great speed and sensitivity to the onset of light; however, they also adapt quickly to constant light or a... (Review)
Review
Vertebrate and invertebrate photoreceptors respond with great speed and sensitivity to the onset of light; however, they also adapt quickly to constant light or a reduction of illumination. During the past year or so, new information has become available concerning the molecular mechanisms by which photoreceptors recover from and adapt to stimuli. These data have identified mechanisms that inactivate nearly every step of the vertebrate and invertebrate phototransduction pathways. Light-induced changes in the concentration of intracellular Ca2+ play an important role in photoreceptor recovery and adaptation. Recently, several proteins that may mediate the effects of Ca2+ on phototransduction have been identified.
Topics: Adaptation, Physiological; Animals; Humans; Photoreceptor Cells; Photoreceptor Cells, Invertebrate; Signal Transduction
PubMed: 7812135
DOI: 10.1016/0959-4388(94)90047-7 -
Visual Neuroscience Sep 2014Vision loss caused by the death of photoreceptors is the leading cause of irreversible blindness in the developed world. Rapid advances in stem cell biology and... (Review)
Review
Vision loss caused by the death of photoreceptors is the leading cause of irreversible blindness in the developed world. Rapid advances in stem cell biology and techniques in cell transplantation have made photoreceptor replacement by transplantation a very plausible therapeutic strategy. These advances include the demonstration of restoration of vision following photoreceptor transplantation and the generation of transplantable populations of donor cells from stem cells. In this review, we present a brief overview of the recent progress in photoreceptor transplantation. We then consider in more detail some of the challenges presented by the degenerating retinal environment that must play host to these transplanted cells, how these may influence transplanted photoreceptor cell integration and survival, and some of the progress in developing strategies to circumnavigate these issues.
Topics: Animals; Humans; Photoreceptor Cells; Retina; Vision Disorders
PubMed: 24945529
DOI: 10.1017/S0952523814000200 -
Journal of the Royal Society, Interface Apr 2010The sensory basis of magnetoreception in animals still remains a mystery. One hypothesis of magnetoreception is that photochemical radical pair reactions can transduce...
The sensory basis of magnetoreception in animals still remains a mystery. One hypothesis of magnetoreception is that photochemical radical pair reactions can transduce magnetic information in specialized photoreceptor cells, possibly involving the photoreceptor molecule cryptochrome. This hypothesis triggered a considerable amount of research in the past decade. Here, we present an updated picture of the radical-pair photoreceptor hypothesis. In our review, we will focus on insights that can assist biologists in their search for the elusive magnetoreceptors.
Topics: Animals; Electromagnetic Fields; Humans; Magnetics; Models, Biological; Orientation; Perception; Photoreceptor Cells
PubMed: 20129953
DOI: 10.1098/rsif.2009.0456.focus -
The Journal of Comparative Neurology Dec 2019Visual opsins coupled with G -type G protein have been considered to be responsible for the vision in mollusks. Recent transcriptomic studies, however, revealed the...
Visual opsins coupled with G -type G protein have been considered to be responsible for the vision in mollusks. Recent transcriptomic studies, however, revealed the presence of opsin mRNA belonging to different groups of opsin subfamilies in the eyes of mollusks. In the present study, we found that at least three different opsins, G -coupled rhodopsin, opsin5A, and xenopsin, are co-expressed in the rhabdomeric photoreceptor cell in the eyes of the terrestrial slug Limax valentianus. These opsins were all localized to the microvilli of the rhabdomere. Co-expression of rhodopsin and opsin5A mRNA was also demonstrated by dual fluorescence in situ hybridization. Co-expression of multiple opsins in the rhabdomeric photoreceptors cells may explain the previously reported shift in the action spectra of the electroretinogram of eyes of Limax flavus between the light- and dark-adapted states, which was also reproduced in the present study in L. valentianus.
Topics: Animals; Gastropoda; Gene Expression; HEK293 Cells; Humans; Opsins; Photoreceptor Cells; Photoreceptor Cells, Invertebrate; Phylogeny
PubMed: 31226228
DOI: 10.1002/cne.24732 -
Investigative Ophthalmology & Visual... Mar 1986Intact rod photoreceptors were dissociated from pronase-treated whole retinas of adult mice by repeated passage through a plastic pipette tip. Hemocytometer counts of...
Intact rod photoreceptors were dissociated from pronase-treated whole retinas of adult mice by repeated passage through a plastic pipette tip. Hemocytometer counts of the cell suspensions indicate that, during a series of ten dissociation steps, a total of about 1-2 million intact photoreceptor cells are dissociated from one adult mouse retina, with less than 5% contamination from Müller cells and neurons of the inner retina. Visual cells with rod outer segments (ROS) and synaptic terminals are released in each step, but they occur in the greatest number during the sixth to ninth steps; detached ROS are released most frequently in the early steps, and neurons of the inner retinal layers appear in the later steps of dissociation. Nuclei are found in each step. Cell intactness was estimated by Trypan blue and Erythrosin B exclusion and by microscopic analysis using differential interference optics or scanning electron microscopy. The cells bind lectins (concanavalin A, Ricinis communis, and wheat germ agglutinin but not peanut agglutinin), displaying surface topography like that observed in situ. The metabolic capacity of dissociated cells was assessed by measuring the utilization of 32P inorganic phosphate for the synthesis of phospholipids and for the light-dependent phosphorylation of rhodopsin. Mature photoreceptor cells were estimated to contain, on average, 6.4 X 10(-12) g DNA, 2.3 X 10(-12) g RNA and 42-64 X 10(-12) g protein. The dissociation procedure provides a population of photoreceptor cells that appears suitable for microscopic, electrophysiological, and biochemical analysis.
Topics: Animals; Cells, Cultured; Mice; Mice, Inbred C57BL; Microscopy, Electron, Scanning; Photoreceptor Cells; Pronase; Retina
PubMed: 3949460
DOI: No ID Found -
Trends in Endocrinology and Metabolism:... Jan 2019Ubiquitous in non-mammalian vertebrates, extra-retinal photoreceptors (ERPs) have been linked to an array of physiological, metabolic, behavioral, and morphological... (Comparative Study)
Comparative Study Review
Ubiquitous in non-mammalian vertebrates, extra-retinal photoreceptors (ERPs) have been linked to an array of physiological, metabolic, behavioral, and morphological changes. However, the mechanisms and functional roles of ERPs remain one of the enduring questions of modern biology. In this review article, we use a comparative framework to identify conserved roles and distributions of ERPs, highlighting knowledge gaps. We conclude that ERP research can be divided into two largely unconnected categories: (i) identification and localization of photoreceptors and (ii) linkage of non-retinal light reception to behavioral and physiological processes, particularly endocrine systems. However, the emergence of novel gene editing and silencing techniques is enabling the unification of ERP research by allowing the bridging of this divide.
Topics: Animals; Behavior, Animal; Brain; Opsins; Photoperiod; Photoreceptor Cells; Vertebrates
PubMed: 30522810
DOI: 10.1016/j.tem.2018.10.005