Photoreceptor Shedding Is Initiated by Light in the Frog Retina

Basinger, Scott F.; Hoffman, Rosemary T.; Matthes, Michael T.

doi:10.1126/science.1086510

Cited by 206 publications

(85 citation statements)

References 6 publications

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“…Recently, it became evident that cGMP is one of the important second messengers together with Ca++-ions to inform the stimulus from the site of bleached rhodopsin by light on the disc membranes to the permeability mechanism of Na+-ions on the plasmalemma of the photoreceptor outer segments (for references, see 27,29,31,34). Biochemically much higher activity of guanylate cyclase has been found in the photoreceptor outer segments (2,16,25,35) together with cGMP-PDEase (8-10, 17, 24) than for adenylate cyclase or cAMPPDEase. Our cytochemical results in the photoreceptor outer segments confirm these biochemical results showing the dominancy of cGMP synthesizing and degrading enzyme activities.…”

Section: Discussionmentioning

confidence: 99%

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Localization of cyclase and cyclic nucleotide phosphodiesterase activities in retinal pigment epithelial cells of the guinea pig.

Ueno¹,

Ueck

1988

Acta Histochem. Cytochem

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The localization of cyclic nucleotide synthesizing-(adenylate cyclase and guanylate cyclase) and degrading-(cAMP-and cGMP-phosphodiesterase) enzyme activities was studied histo-and cytochemically in the retinal pigment epithelial cells (RPE) by means of newly developed methods. Adenylate cyclase activity was localized on the apical plasmalemma and gap junctions of the RPE, but not on the outer segments of the photoreceptors held by apical plasmalemma of the RPE. Guanylate cyclase activity was observed on the apical plasmalemma and gap junctions of the RPE, and also intensely on the disc and plasma membranes of the photoreceptor outer segments. cAMP-phosphodiesterase activity was localized on the apical plasmalemma of the RPE, but no reaction products were seen on the gap junctions and on the outer segments. In contrast, intense cGMP-phosphodieterase activity was observed both on the apical plasmalemma of the RPE and in the outer segments. There were no notable reaction precipitates on the gap junctions of the RPE.In the control experiments, cAMP-and cGMP-phosphodiesterase activity was drastically inhibited both in the RPE and outer segments by 2 mM IBMX or 5 mM theophyline, two potent inhibitors to cyclic nucleotide phosphodiesterse. No such specific potent inhibitors exist for cyclase. The results are discussed in connection with the phagocytotic activity and other important functions of the RPE cells.It is well established in several vertebrate species that retinal pigment epithelial cells (RPE) play an essential role in the process of renewal of photoreceptor outer segments through the phagocytosis of shed outer segments. Both shedding of the outer segments of rods (6,22,36) and cones (2,19,20) and phagocytosis by the RPE cells show a daily rhythm. In invertebrate this shedding is under the control of the central nervous system (7), whereas in the higher verteblates the circadian oscillator seems of exist within the eye (13, 15). A possible involvement of cyclic adenosine monophosphate (cAMP) (3,4,11,18) or cyclic guanosine monophosphate (cGMP) (23) has been discussed as intracellular second messengers of the clock system which controls phagocytosis of the RPE. Melatonine and taurine were claimed to be the exgenous factors which control the enzyme activities mediating the cAMP and cGMP 45

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Section: Discussionmentioning

confidence: 99%

“…Both shedding of the outer segments of rods (6,22,36) and cones (2,19,20) and phagocytosis by the RPE cells show a daily rhythm. In invertebrate this shedding is under the control of the central nervous system (7), whereas in the higher verteblates the circadian oscillator seems of exist within the eye (13,15).…”

mentioning

confidence: 99%

Localization of cyclase and cyclic nucleotide phosphodiesterase activities in retinal pigment epithelial cells of the guinea pig.

Ueno¹,

Ueck

1988

Acta Histochem. Cytochem

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“…15 At the same time, it has been well established that physiological light exposure is implicated in the initiation and promotion of OS shedding by photoreceptor cells, and the shed OS are phagocytosed by RPE cells. [16][17][18][19][20][21] Based on this previous evidence, we speculated that exposure to IPL could increase VEGF expression in mouse RPE in vivo. VEGF protein produced in RPE is released basolaterally into the choroidal vasculature, an event implicated in both the maintenance of the choroidal vasculature 16,22 and the pathological CNV.…”

Section: Ipl Upregulates Vegf Expression In Rpe Of Wt Micementioning

confidence: 99%

Intense Physiological Light Upregulates Vascular Endothelial Growth Factor and Enhances Choroidal Neovascularization via Peroxisome Proliferator-Activated Receptor γ Coactivator-1α in Mice

Ueta

Inoue

Yuda

et al. 2012

ATVB

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Objectives— Toxicity of intense light to facilitate the development of neovascular age-related macular degeneration has been a health concern although the mechanism remains unclear. Methods and Results— Effects of intense, but within physiological range, light on retinal pigment epithelium, a major pathogenic origin of age-related macular degeneration were studied in mice. Intense physiological light upregulated vascular endothelial growth factor (VEGF) expression in retinal pigment epithelium, independent of circadian rhythm, which resulted in enhancement of choroidal neovascularization. In rd1/rd1 mice or Crx −/− mice that do not possess outer segment structure, light exposure did not induce VEGF, indicating that VEGF upregulation by light depended on increased outer segment phagocytosis by retinal pigment epithelium. In retinal pigment epithelium cells phagocytosing increased amount of outer segment, peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) not hypoxia-inducible factor-1α was induced, leading to VEGF upregulation. The VEGF upregulation and choroidal neovascularization enhancement were abrogated in PGC-1α −/− mice and estrogen-related receptor-α −/− mice, indicating the involvement of PGC-1α/estrogen-related receptor-α pathway. Conclusions— Intense physiological light is involved in choroidal neovascularization through excess outer segment phagocy-tosis and VEGF upregulation mediated by PGC-1α in vivo.

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“…37 In addition, photoreceptors periodically shed their distal ciliary tips containing the bleached photopigment. 38 Such shedding triggers replenishment of the ciliary membrane and associated proteins at the proximal end. It is estimated that approximately 2,000 molecules of rhodopsin are transported per minute in a normal human retina.…”

Section: Small Gtpases In Ciliary Protein Traffickingmentioning

confidence: 99%

Role of small GTPases in polarized vesicle transport to primary cilium

Rao¹,

Khanna²

2015

RRB

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Small GTPases play crucial roles in regulating polarized vesicle trafficking in a cell. These molecules are involved in diverse pathways and regulate cell shape, organelle integrity, and cell signaling. One of the most important cellular signaling centers is the primary or sensory cilium. Small GTPases orchestrate a diverse set of events to not only generate these structures but also mediate their function and maintenance during the life of the cell. In this review, we will discuss the various small GTPases involved in regulating cilia biogenesis and function and their involvement in human diseases.

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Photoreceptor Shedding Is Initiated by Light in the Frog Retina

Cited by 206 publications

References 6 publications

Localization of cyclase and cyclic nucleotide phosphodiesterase activities in retinal pigment epithelial cells of the guinea pig.

Localization of cyclase and cyclic nucleotide phosphodiesterase activities in retinal pigment epithelial cells of the guinea pig.

Intense Physiological Light Upregulates Vascular Endothelial Growth Factor and Enhances Choroidal Neovascularization via Peroxisome Proliferator-Activated Receptor γ Coactivator-1α in Mice

Role of small GTPases in polarized vesicle transport to primary cilium

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