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From extraocular photoreception to pigment movement regulation: a new control mechanism of the lanternshark luminescence. Sci Rep 2020; 10:10195. [PMID: 32576969 PMCID: PMC7311519 DOI: 10.1038/s41598-020-67287-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 05/28/2020] [Indexed: 11/08/2022] Open
Abstract
The velvet belly lanternshark, Etmopterus spinax, uses counterillumination to disappear in the surrounding blue light of its marine environment. This shark displays hormonally controlled bioluminescence in which melatonin (MT) and prolactin (PRL) trigger light emission, while α-melanocyte-stimulating hormone (α-MSH) and adrenocorticotropic hormone (ACTH) play an inhibitory role. The extraocular encephalopsin (Es-Opn3) was also hypothesized to act as a luminescence regulator. The majority of these compounds (MT, α-MSH, ACTH, opsin) are members of the rapid physiological colour change that regulates the pigment motion within chromatophores in metazoans. Interestingly, the lanternshark photophore comprises a specific iris-like structure (ILS), partially composed of melanophore-like cells, serving as a photophore shutter. Here, we investigated the role of (i) Es-Opn3 and (ii) actors involved in both MT and α-MSH/ACTH pathways on the shark bioluminescence and ILS cell pigment motions. Our results reveal the implication of Es-Opn3, MT, inositol triphosphate (IP3), intracellular calcium, calcium-dependent calmodulin and dynein in the ILS cell pigment aggregation. Conversely, our results highlighted the implication of the α-MSH/ACTH pathway, involving kinesin, in the dispersion of the ILS cell pigment. The lanternshark luminescence then appears to be controlled by the balanced bidirectional motion of ILS cell pigments within the photophore. This suggests a functional link between photoreception and photoemission in the photogenic tissue of lanternsharks and gives precious insights into the bioluminescence control of these organisms.
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Abstract
Muscarinic agonists act mainly via muscarinic M₃ cholinoceptors to cause contraction of the iris sphincter, ciliary muscle and trabecular meshwork as well as increase outflow facility of aqueous humour. In the iris dilator, the effect of muscarinic agonists is species dependent but is predominantly relaxation via muscarinic M₃ receptors. In the conjunctiva, muscarinic agonists stimulate goblet cell secretion which contributes to the protective tear film. Muscarinic M₂ and M₃ receptors appear mainly involved. In the lens muscarinic agonists act via muscarinic M₁ receptors to produce depolarization and increase [Ca(2+)](i). All five subtypes of muscarinic receptor are present in the retina. In the developing retina, acetylcholine appears to limit purinergic stimulation of retinal development and decrease cell proliferation. In the adult retina acetylcholine and other muscarinic agonists may have complex effects, for example, enhancing light-evoked neuronal firing in transient ON retinal ganglion cells and inhibiting firing in OFF retinal ganglion cells. In the lacrimal gland, muscarinic agonists activate M₃ receptors on secretory globular acinar cells to stimulate tear secretion and also cause contraction of myoepithelial cells. In Sjögren's syndrome, antibodies to the muscarinic M₃ receptor disrupt normal gland function leading to xerophthalmia although the mechanism of action of the antibody is still not clear. Atropine and pirenzepine are useful in limiting the development of myopia in children probably by an action on muscarinic receptors in the sclera, although many other muscarinic receptor antagonists are not effective.
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Affiliation(s)
- Frederick Mitchelson
- Department of Pharmacology, University of Melbourne, Melbourne, VIC 3010, Australia.
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Nuckels RJ, Forstner MRJ, Capalbo-Pitts EL, García DM. Developmental expression of muscarinic receptors in the eyes of zebrafish. Brain Res 2011; 1405:85-94. [PMID: 21741623 DOI: 10.1016/j.brainres.2011.06.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2010] [Revised: 06/03/2011] [Accepted: 06/05/2011] [Indexed: 11/25/2022]
Abstract
In previous work, we have shown that light-adaptive pigment granule dispersion can be induced in vitro by treating retinal pigment epithelium (RPE) isolated from bluegill retina with acetylcholine or its analog carbachol and that these agents act through muscarinic receptors to induce pigment granule dispersion. RPE is a monolayer of tissue found between the neural retina and the choroid. In fish, RPE has long apical projections enmeshed with the distal part of photoreceptors, reaching down to the level of their nuclei. The RPE disperses melanin pigment granules into the apical projections to shield light-sensitive photoreceptor outer segments from photobleaching when fish are under bright-light conditions. During development, RPE begin to respond to light at 5days post-fertilization, raising the question of whether responsiveness is correlated to receptor expression. Here, we isolate, clone and sequence chrm-odd receptor genes in zebrafish, characterize them phylogenetically and observe their expression in the eyes of the zebrafish at different developmental stages using RT-PCR and immunofluorescence microscopy. We find that zebrafish express six unique chrm-odd receptor subtypes: chrm1a, chrm1b, chrm3a, chrm3b, chrm5a and chrm5b - and these receptors are differentially expressed during development. Our phylogenetic analysis confirms the assignments of chrm1b and chrm5b, isolated here, as well as other muscarinic receptor genes and their duplicates and suggests previously described muscarinic receptors may need to be reclassified. Differences between the expression patterns of ostensibly duplicated genes raise the possibility that subtle differences between the duplicates may enable refined regulation of specific developmental events.
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Affiliation(s)
- Richard J Nuckels
- Department of Biology, Texas State University-San Marcos, 601 University Drive, San Marcos, Texas 78666, USA.
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Tan J, Deng ZH, Liu SZ, Wang JT, Huang C. TGF-β2 in Human Retinal Pigment Epithelial Cells: Expression and Secretion Regulated by Cholinergic Signals In Vitro. Curr Eye Res 2009; 35:37-44. [DOI: 10.3109/02713680903374190] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Jia Tan
- Department of Ophthalmology, Xiangya Medical College, Central South University, Changsha, China
| | - Zhi-hong Deng
- Eye Center, Tianjin Medical University, Tianjin, China
| | - Shuang-zhen Liu
- Department of Ophthalmology, Xiangya Medical College, Central South University, Changsha, China
| | - Jian-tao Wang
- Eye Center, Tianjin Medical University, Tianjin, China
| | - Chen Huang
- Cancer Research Institute, Central South University, Changsha, China
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Seo JS, Kim MS, Park EM, Ahn SJ, Kim NY, Jung SH, Kim JW, Lee HH, Chung JK. Cloning and characterization of muscarinic receptor genes from the nile tilapia (Oreochromis niloticus). Mol Cells 2009; 27:383-90. [PMID: 19326086 DOI: 10.1007/s10059-009-0048-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2008] [Revised: 11/12/2008] [Accepted: 12/04/2008] [Indexed: 10/21/2022] Open
Abstract
To investigate the regulatory mechanism underlying the contractile response in the intestinal smooth muscle of the nile tilapia (Orechromis niloticus), we used pharmacologic and molecular approaches to identify the muscarinic subreceptors and the intracellular signaling pathways involved in this motility. Myography assays revealed that an M1- and M3-subtype selective antagonist, but not a M2-subtype selective antagonist, inhibited carbachol HCI (CCH)-induced intestinal smooth muscle contraction. In addition, a phospholipase C inhibitor, but not an adenylate cyclase inhibitor, blocked the contractile response to CCH. We also cloned five muscarinic genes (OnM2A, OnM2B, OnM3, OnM5A, and OnM5B) from the nile tilapia. In the phylogenetic analysis and sequence comparison to compare our putative gene products (OnMs) with the sequences obtained from the near complete teleost genomes, we unexpectedly found that the teleost fish have respectively two paralogous genes corresponding to each muscarinic subreceptor, and other teleost fish, except zebrafish, do not possess muscarinic subreceptor M1. In addition, the expression pattern of the nile tilapia muscarinic subreceptor transcripts during CCH-induced intestinal smooth muscle contraction in the proximal intestinal tissue was analyzed by real-time PCR surveys and it was demonstrated that CCH increased the OnMs m RNA expression rapidly and transiently.
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Affiliation(s)
- Jung Soo Seo
- Pathology Division, National Fisheries Research and Development Institute, Busan 619-902, Korea
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Sekiguchi-Tonosaki M, Obata M, Haruki A, Himi T, Kosaka J. Acetylcholine induces Ca2+ signaling in chicken retinal pigmented epithelial cells during dedifferentiation. Am J Physiol Cell Physiol 2009; 296:C1195-206. [PMID: 19244481 DOI: 10.1152/ajpcell.00423.2008] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Retinal pigmented epithelial cells exchange their cellular phenotypes into lens cells and neurons, via depigmented and non-epithelial-shaped dedifferentiated intermediates. Because these dedifferentiated cells can either revert to pigmented epithelial cells or transdifferentiate into lens cells and/or neurons, they are recognized as candidates for lens and retinal cell regeneration. The purpose of the present study was to elucidate the signal transduction pathways between chicken retinal pigmented epithelial cells and their dedifferentiated intermediates. We monitored intracellular Ca(2+) concentrations using Fluo-4-based Ca(2+) optical imaging and focused on cellular responses to the neurotransmitter acetylcholine. Muscarinic Ca(2+) mobilization was observed both in retinal pigmented epithelial cells and in dedifferentiated cells, and was inhibited by atropine. The muscarine-dependent acetylcholine response depended on Ca(2+) release from intracellular Ca(2+) stores, which was completely blocked by thapsigargin. In contrast, the nicotine-dependent acetylcholine response that led to Ca(2+) influx through L-type Ca(2+) channels was inhibited by alpha-bungarotoxin and attenuated by nifedipine, and it was detected only in the dedifferentiated intermediates. Application of (S)-(-)-BayK8644 elevated intracellular Ca(2+) both in retinal pigmented epithelial cells and in dedifferentiated intermediates; however, the nicotinic response was not observed in pigmented epithelial cells. Another L-type Ca(2+) channel blocker, diltiazem, also blocked the nicotine-dependent acetylcholine response in dedifferentiated cells and maintained the epithelial-like morphology of retinal pigmented epithelial cells. Our results indicate that an alternative acetylcholine signaling pathway is used during the dedifferentiation process of retinal pigmented epithelial cells.
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Affiliation(s)
- Mariko Sekiguchi-Tonosaki
- Dept. of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Okayama 700-8558, Japan
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Carbachol-mediated pigment granule dispersion in retinal pigment epithelium requires Ca2+ and calcineurin. BMC Cell Biol 2007; 8:53. [PMID: 18093324 PMCID: PMC2225403 DOI: 10.1186/1471-2121-8-53] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2007] [Accepted: 12/19/2007] [Indexed: 11/30/2022] Open
Abstract
Background Inside bluegill (Lepomis macrochirus) retinal pigment epithelial cells, pigment granules move in response to extracellular signals. During the process of aggregation, pigment motility is directed toward the cell nucleus; in dispersion, pigment is directed away from the nucleus and into long apical processes. A number of different chemicals have been found to initiate dispersion, and carbachol (an acetylcholine analog) is one example. Previous research indicates that the carbachol-receptor interaction activates a Gq-mediated pathway which is commonly linked to Ca2+ mobilization. The purpose of the present study was to test for involvement of calcium and to probe calcium-dependent mediators to reveal their role in carbachol-mediated dispersion. Results Carbachol-induced pigment granule dispersion was blocked by the calcium chelator BAPTA. In contrast, the calcium channel antagonist verapamil, and incubation in Ca2+-free medium failed to block carbachol-induced dispersion. The calcineurin inhibitor cypermethrin blocked carbachol-induced dispersion; whereas, two protein kinase C inhibitors (staurosporine and bisindolylmaleimide II) failed to block carbachol-induced dispersion, and the protein kinase C activator phorbol 12-myristate 13-acetate failed to elicit dispersion. Conclusion A rise in intracellular calcium is necessary for carbachol-induced dispersion; however, the Ca2+ requirement is not dependent on extracellular sources, implying that intracellular stores are sufficient to enable pigment granule dispersion to occur. Calcineurin is a likely Ca2+-dependent mediator involved in the signal cascade. Although the pathway leads to the generation of diacylglycerol and calcium (both required for the activation of certain PKC isoforms), our evidence does not support a significant role for PKC.
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Shmuel M, Nodel-Berner E, Hyman T, Rouvinski A, Altschuler Y. Caveolin 2 regulates endocytosis and trafficking of the M1 muscarinic receptor in MDCK epithelial cells. Mol Biol Cell 2007; 18:1570-85. [PMID: 17314410 PMCID: PMC1855036 DOI: 10.1091/mbc.e06-07-0618] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Clathrin and caveolins are known for their involvement in the internalization of numerous receptors. Here we show that in polarized epithelial Madin-Darby canine kidney cells, both the clathrin machinery and caveolins are involved in the endocytosis and delivery to the plasma membrane (PM) of the M1 muscarinic acetylcholine receptor (mAChR). We initially localized this receptor to the lateral membrane, where it accumulates proximal to the tight junctions. From there it is internalized through the clathrin-mediated pathway. In addition, the receptor may associate on the PM with caveolin (cav) 2 or in intracellular compartments with either cav 2, or monomeric or oligomeric cav 1. Association of the PM M1 mAChR with cav 2 inhibits receptor endocytosis through the clathrin-mediated pathway or retains the receptor in an intracellular compartment. This intracellular association attenuates receptor trafficking. Expression of cav 1 with cav 2 rescues the latter's inhibitory effect. The caveolins stimulate M1 mAChR oligomerization thus maintaining a constant amount of monomeric receptor. These results provide evidence that caveolins play a role in the attenuation of the M1 muscarinic receptor's intracellular trafficking to and from the PM.
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Affiliation(s)
- Miriam Shmuel
- Department of Pharmacology, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Efrat Nodel-Berner
- Department of Pharmacology, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Tehila Hyman
- Department of Pharmacology, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Alexander Rouvinski
- Department of Pharmacology, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Yoram Altschuler
- Department of Pharmacology, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
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