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Fjaervoll HK, Fjaervoll KA, Yang M, Reiten OK, Bair J, Lee C, Utheim TP, Dartt D. Purinergic agonists increase [Ca 2+] i in rat conjunctival goblet cells through ryanodine receptor type 3. Am J Physiol Cell Physiol 2024; 327:C830-C843. [PMID: 39099424 PMCID: PMC11427011 DOI: 10.1152/ajpcell.00291.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2024] [Revised: 07/08/2024] [Accepted: 07/24/2024] [Indexed: 08/06/2024]
Abstract
ATP and benzoylbenzoyl-ATP (BzATP) increase free cytosolic Ca2+ concentration ([Ca2+]i) in conjunctival goblet cells (CGCs) resulting in mucin secretion. The purpose of this study was to investigate the source of the Ca2+i mobilized by ATP and BzATP. First-passage cultured rat CGCs were incubated with Fura-2/AM, and [Ca2+]i was measured under several conditions with ATP and BzATP stimulation. The following conditions were used: 1) preincubation with the Ca2+ chelator EGTA, 2) preincubation with the SERCA inhibitor thapsigargin (10-6 M), which depletes ER Ca2+ stores, 3) preincubation with phospholipase C (PLC) or protein kinase A (PKA) inhibitor, or 4) preincubation with the voltage-gated calcium channel antagonist nifedipine (10-5 M) and the ryanodine receptor (RyR) antagonist dantrolene (10-5 M). Immunofluorescence microscopy (IF) and quantitative reverse transcription polymerase chain reaction (RT-qPCR) were used to investigate RyR presence in rat and human CGCs. ATP-stimulated peak [Ca2+]i was significantly lower after chelating Ca2+i with 2 mM EGTA in Ca2+-free buffer. The peak [Ca2+]i increase in CGCs preincubated with thapsigargin, the PKA inhibitor H89, nifedipine, and dantrolene, but not the PLC inhibitor, was reduced for ATP at 10-5 M and BzATP at 10-4 M. Incubating CGCs with dantrolene alone decreased [Ca2+]i and induced CGC cell death at a high concentration. RyR3 was detected in rat and human CGCs with IF and RT-qPCR. We conclude that ATP- and BzATP-induced Ca2+i increases originate from the ER and that RyR3 may be an essential regulator of CGC [Ca2+]i. This study contributes to the understanding of diseases arising from defective Ca2+ signaling in nonexcitable cells.NEW & NOTEWORTHY ATP and benzoylbenzoyl-ATP (BzATP) induce mucin secretion through an increase in free cytosolic calcium concentration ([Ca2+]i) in conjunctival goblet cells (CGCs). The mechanisms through which ATP and BzATP increase [Ca2+]i in CGCs are unclear. Ryanodine receptors (RyRs) are fundamental in [Ca2+]i regulation in excitable cells. Herein, we find that ATP and BzATP increase [Ca2+]i through the activation of protein kinase A, voltage-gated calcium channels, and RyRs, and that RyRs are crucial for nonexcitable CGCs' Ca2+i homeostasis.
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Affiliation(s)
- Haakon K Fjaervoll
- Division of Head, Neck and Reconstructive Surgery, Faculty of Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
- Department of Plastic and Reconstructive Surgery, Oslo University Hospital, Oslo, Norway
| | - Ketil A Fjaervoll
- Division of Head, Neck and Reconstructive Surgery, Faculty of Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
- Department of Plastic and Reconstructive Surgery, Oslo University Hospital, Oslo, Norway
| | - Menglu Yang
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States
| | - Ole K Reiten
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States
| | - Jeffrey Bair
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States
| | - Changrim Lee
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States
| | - Tor P Utheim
- Division of Head, Neck and Reconstructive Surgery, Faculty of Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
- Department of Plastic and Reconstructive Surgery, Oslo University Hospital, Oslo, Norway
| | - Darlene Dartt
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States
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Epigallocatechin-3-gallate mobilizes intracellular Ca 2+ in prostate cancer cells through combined Ca 2+ entry and Ca 2+-induced Ca 2+ release. Life Sci 2020; 258:118232. [PMID: 32781066 DOI: 10.1016/j.lfs.2020.118232] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/31/2020] [Accepted: 08/05/2020] [Indexed: 12/28/2022]
Abstract
AIMS To elucidate the mechanism by which (-)-epigallocatechin-3-gallate (EGCG) mediates intracellular Ca2+ increase in androgen-independent prostate cancer (PCa) cells. MAIN METHODS Following exposure to different doses of EGCG, viability of DU145 and PC3 PCa cells was evaluated by MTT assay and the intracellular Ca2+ dynamics by the fluorescent Ca2+ chelator Fura-2. The expression of different channels was investigated by qPCR analysis and sulfhydryl bonds by Ellman's assay. KEY FINDINGS EGCG inhibited DU145 and PC3 proliferation with IC50 = 46 and 56 μM, respectively, and induced dose-dependent peaks of internal Ca2+ that were dependent on extracellular Ca2+. The expression of TRPC4 and TRPC6 channels was revealed by qPCR in PC3 cells, but lack of effect by modulators and blockers ruled out an exclusive role for these, as well as for voltage-dependent T-type Ca2+ channels. Application of dithiothreitol and catalase and sulfhydryl (SH) measurements showed that EGCG-induced Ca2+ rise depends on SH oxidation, while the effect of EGTA, dantrolene, and the PLC inhibitor U73122 suggested that EGCG-induced Ca2+ influx acts as a trigger for Ca2+-induced Ca2+ release, involving both ryanodine and IP3 receptors. Different from EGCG, ATP caused a rapid Ca2+ increase, which was independent of external Ca2+, but sensitive to U73122. SIGNIFICANCE EGCG induces an internal Ca2+ increase in PCa cells by a multi-step mechanism. As dysregulation of cytosolic Ca2+ is directly linked to apoptosis in PCa cells, these data confirm the possibility of using EGCG as a synergistic adjuvant in combined therapies for recalcitrant malignancies like androgen-independent PCa.
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Barrett JN, Rincon S, Singh J, Matthewman C, Pasos J, Barrett EF, Rajguru SM. Pulsed infrared releases Ca 2+ from the endoplasmic reticulum of cultured spiral ganglion neurons. J Neurophysiol 2018; 120:509-524. [PMID: 29668377 DOI: 10.1152/jn.00740.2017] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Inner ear spiral ganglion neurons were cultured from day 4 postnatal mice and loaded with a fluorescent Ca2+ indicator (fluo-4, -5F, or -5N). Pulses of infrared radiation (IR; 1,863 nm, 200 µs, 200-250 Hz for 2-5 s, delivered via an optical fiber) produced a rapid, transient temperature increase of 6-12°C (above a baseline of 24-30°C). These IR pulse trains evoked transient increases in both nuclear and cytosolic Ca2+ concentration ([Ca2+]) of 0.20-1.4 µM, with a simultaneous reduction of [Ca2+] in regions containing endoplasmic reticulum (ER). IR-induced increases in cytosolic [Ca2+] continued in medium containing no added Ca2+ (±Ca2+ buffers) and low [Na+], indicating that the [Ca2+] increase was mediated by release from intracellular stores. Consistent with this hypothesis, the IR-induced [Ca2+] response was prolonged and eventually blocked by inhibition of ER Ca2+-ATPase with cyclopiazonic acid, and was also inhibited by a high concentration of ryanodine and by inhibitors of inositol (1,4,5)-trisphosphate (IP3)-mediated Ca2+ release (xestospongin C and 2-aminoethoxydiphenyl borate). The thermal sensitivity of the response suggested involvement of warmth-sensitive transient receptor potential (TRP) channels. The IR-induced [Ca2+] increase was inhibited by TRPV4 inhibitors (HC-067047 and GSK-2193874), and immunostaining of spiral ganglion cultures demonstrated the presence of TRPV4 and TRPM2 that colocalized with ER marker GRP78. These results suggest that the temperature sensitivity of IR-induced [Ca2+] elevations is conferred by TRP channels on ER membranes, which facilitate Ca2+ efflux into the cytosol and thereby contribute to Ca2+-induced Ca2+-release via IP3 and ryanodine receptors. NEW & NOTEWORTHY Infrared radiation-induced photothermal effects release Ca2+ from the endoplasmic reticulum of primary spiral ganglion neurons. This Ca2+ release is mediated by activation of transient receptor potential (TRPV4) channels and involves amplification by Ca2+-induced Ca2+-release. The neurons immunostained for warmth-sensitive channels, TRPV4 and TRPM2, which colocalize with endoplasmic reticulum. Pulsed infrared radiation provides a novel experimental tool for releasing intracellular Ca2+, studying Ca2+ regulatory mechanisms, and influencing neuronal excitability.
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Affiliation(s)
- John N Barrett
- Department of Physiology and Biophysics, University of Miami , Miami, Florida.,Neuroscience Program, University of Miami , Miami, Florida
| | - Samantha Rincon
- Department of Biomedical Engineering, University of Miami , Miami, Florida
| | - Jayanti Singh
- Department of Otolaryngology, University of Miami , Miami, Florida
| | | | - Julio Pasos
- Department of Otolaryngology, University of Miami , Miami, Florida
| | - Ellen F Barrett
- Department of Physiology and Biophysics, University of Miami , Miami, Florida.,Neuroscience Program, University of Miami , Miami, Florida
| | - Suhrud M Rajguru
- Department of Biomedical Engineering, University of Miami , Miami, Florida.,Department of Otolaryngology, University of Miami , Miami, Florida
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Aguilar-Roblero R, Quinto D, Báez-Ruíz A, Chávez JL, Belin AC, Díaz-Muñoz M, Michel S, Lundkvist G. Ryanodine-sensitive intracellular Ca 2+ channels are involved in the output from the SCN circadian clock. Eur J Neurosci 2016; 44:2504-2514. [PMID: 27529310 PMCID: PMC5053303 DOI: 10.1111/ejn.13368] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 08/03/2016] [Accepted: 08/09/2016] [Indexed: 01/07/2023]
Abstract
The suprachiasmatic nuclei (SCN) contain the major circadian clock responsible for generation of circadian rhythms in mammals. The time measured by the molecular circadian clock must eventually be translated into a neuronal firing rate pattern to transmit a meaningful signal to other tissues and organs in the animal. Previous observations suggest that circadian modulation of ryanodine receptors (RyR) is a key element of the output pathway from the molecular circadian clock. To directly test this hypothesis, we studied the effects of RyR activation and inhibition on real time expression of PERIOD2::LUCIFERASE, intracellular calcium levels and spontaneous firing frequency in mouse SCN neurons. Furthermore, we determined whether the RyR-2 mRNA is expressed with a daily variation in SCN neurons. We provide evidence that pharmacological manipulation of RyR in mice SCN neurons alters the free [Ca2+ ]i in the cytoplasm and the spontaneous firing without affecting the molecular clock mechanism. Our data also show a daily variation in RyR-2 mRNA from single mouse SCN neurons with highest levels during the day. Together, these results confirm the hypothesis that RyR-2 is a key element of the circadian clock output from SCN neurons.
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Affiliation(s)
- Raúl Aguilar-Roblero
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Ciudad Universitaria, Coyoacan, Mexico City D.F, 04510, México.
| | - Daniel Quinto
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Ciudad Universitaria, Coyoacan, Mexico City D.F, 04510, México
| | - Adrian Báez-Ruíz
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Juriquilla Querétaro, México
| | - José Luis Chávez
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Ciudad Universitaria, Coyoacan, Mexico City D.F, 04510, México
| | | | - Mauricio Díaz-Muñoz
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Juriquilla Querétaro, México
| | - Stephan Michel
- Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands
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Martínez-Ramírez AS, Vázquez-Cuevas FG. Purinergic signaling in the ovary. Mol Reprod Dev 2015; 82:839-48. [PMID: 26275037 DOI: 10.1002/mrd.22537] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 08/05/2015] [Indexed: 01/27/2023]
Abstract
Adenosine triphosphate (ATP) is released from the cell by multiple mechanisms. The extracellular form of this purine is processed by ectonucleotidases, resulting in a variety of dephosphorylated metabolites that can bind to specific receptors found in the membrane of target cells; such purinergic signaling is important as an autocrine-paracrine intercellular communication system that influences tissue physiology. In this review, we summarize the studies analyzing purinergic activity in the ovary, which can modulate cellular physiology-including sensitivity to gonadotropins-in several ovarian cell types, including the cumulus-cell complex, granulosa cells, theca cells, and the ovarian surface epithelium. These functions support a role for ATP as an important intra-ovarian messenger, and open new lines of research that can improve our understanding of mechanisms regulating ovarian function and the fine-tuning of folliculogenesis.
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Affiliation(s)
- Angélica S Martínez-Ramírez
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Juriquilla Querétaro, Querétaro, México
| | - Francisco G Vázquez-Cuevas
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Juriquilla Querétaro, Querétaro, México
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Abstract
Adenosine-5'-triphosphate is released by neuroendocrine, endocrine, and other cell types and acts as an extracellular agonist for ligand-gated P2X cationic channels and G protein-coupled P2Y receptors in numerous organs and tissues, including the endocrine system. The breakdown of ATP by ectonucleotidases not only terminates its extracellular messenger functions, but also provides a pathway for the generation of two additional agonists: adenosine 5'-diphosphate, acting via some P2Y receptors, and adenosine, a native agonist for G protein-coupled adenosine receptors, also expressed in the endocrine system. This article provides a review of purinergic signaling pathways in the hypothalamic magnocellular neurosecretory cells and neurohypophysis, hypothalamic parvocellular neuroendocrine system, adenohypophysis, and effector glands organized in five axes: hypothalamic-pituitary-gonadal, hypothalamic-pituitary-thyroid, hypothalamic-pituitary-adrenal, hypothalamic-pituitary-growth hormone, and hypothalamic-pituitary-prolactin. We attempted to summarize current knowledge of purinergic receptor subtypes expressed in the endocrine system, including their roles in intracellular signaling, hormone secretion, and other cell functions. We also briefly review the release mechanism for adenosine-5'-triphosphate by neuroendocrine, endocrine and surrounding cells, the enzymes involved in adenosine-5'-triphosphate hydrolysis to adenosine-5'-diphosphate and adenosine, and the relevance of this pathway for sequential activation of receptors and termination of signaling.
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Wright MF, Bowdridge E, McDermott EL, Richardson S, Scheidler J, Syed Q, Bush T, Inskeep EK, Flores JA. Mechanisms of intracellular calcium homeostasis in developing and mature bovine corpora lutea. Biol Reprod 2014; 90:55. [PMID: 24501170 DOI: 10.1095/biolreprod.113.113662] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Although calcium (Ca(2+)) is accepted as an intracellular mediator of prostaglandin F2 alpha (PGF2alpha) actions on luteal cells, studies defining mechanisms of Ca(2+) homeostasis in bovine corpora lutea (CL) are lacking. The increase in intracellular Ca(2+) concentration ([Ca(2+)]i) induced by PGF2alpha in steroidogenic cells from mature CL is greater than in those isolated from developing CL. Our hypothesis is that differences in signal transduction associated with developing and mature CL contribute to the increased efficacy of PGF2alpha to induce a Ca(2+) signal capable of inducing regression in mature CL. To test this hypothesis, major genes participating in Ca(2+) homeostasis in the bovine CL were identified, and expression of mRNA, protein, or activity, in the case of phospholipase Cbeta (PLCbeta), in developing and mature bovine CL was compared. In addition, we examined the contribution of external and internal Ca(2+) to the PGF2alpha stimulated rise in [Ca(2+)]i in LLCs isolated from developing and mature bovine CL. Three differences were identified in mechanisms of calcium homeostasis between developing and mature CL, which could account for the lesser increase in [Ca(2+)]i in response to PGF2alpha in developing than in mature CL. First, there were lower concentrations of inositol 1,4,5-trisphosphate (IP3) after similar PGF2alpha challenge, indicating reduced phospholipase C beta (PLCbeta) activity, in developing than mature CL. Second, there was an increased expression of sorcin (SRI) in developing than in mature CL. This cytoplasmic Ca(2+) binding protein modulates the endoplasmic reticulum (ER) Ca(2+) release channel, ryanodine receptor (RyR), to be in the closed configuration. Third, there was greater expression of ATP2A2 or SERCA, which causes calcium reuptake into the ER, in developing than in mature CL. Developmental differences in expression detected in whole CL were confirmed by Western blots using protein samples from steroidogenic cells isolated from developing and mature CL. Localization of these genes in steroidogenic luteal cells was confirmed by immunohistochemistry. Therefore, it is concluded that the cellular mechanisms that allow PGF2alpha to induce a calcium signal of greater magnitude in mature than in developing CL involve 1) greater PLCbeta activity with enhanced generation of IP3, 2) an enhanced Ca(2+) release from the ER via unrestrained RYR2 due to a decrease in SRI expression, and 3) a reduction in calcium reuptake to the ER due to lower expression of ATP2A2. Accordingly, the increase in [Ca(2+)]i induced by PGF2alpha in mature large steroidogenic cells had less dependency from extracellular calcium than in those isolated from immature CL.
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Affiliation(s)
- Marietta F Wright
- Division of Animal and Nutritional Sciences, Davis College of Agriculture, Natural Resources and Design, West Virginia University, Morgantown, West Virginia
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Burnstock G. Purinergic signalling in endocrine organs. Purinergic Signal 2014; 10:189-231. [PMID: 24265070 PMCID: PMC3944044 DOI: 10.1007/s11302-013-9396-x] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 10/24/2013] [Indexed: 01/08/2023] Open
Abstract
There is widespread involvement of purinergic signalling in endocrine biology. Pituitary cells express P1, P2X and P2Y receptor subtypes to mediate hormone release. Adenosine 5'-triphosphate (ATP) regulates insulin release in the pancreas and is involved in the secretion of thyroid hormones. ATP plays a major role in the synthesis, storage and release of catecholamines from the adrenal gland. In the ovary purinoceptors mediate gonadotrophin-induced progesterone secretion, while in the testes, both Sertoli and Leydig cells express purinoceptors that mediate secretion of oestradiol and testosterone, respectively. ATP released as a cotransmitter with noradrenaline is involved in activities of the pineal gland and in the neuroendocrine control of the thymus. In the hypothalamus, ATP and adenosine stimulate or modulate the release of luteinising hormone-releasing hormone, as well as arginine-vasopressin and oxytocin. Functionally active P2X and P2Y receptors have been identified on human placental syncytiotrophoblast cells and on neuroendocrine cells in the lung, skin, prostate and intestine. Adipocytes have been recognised recently to have endocrine function involving purinoceptors.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF, UK,
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Burnstock G. Purinergic signalling in the reproductive system in health and disease. Purinergic Signal 2014; 10:157-87. [PMID: 24271059 PMCID: PMC3944041 DOI: 10.1007/s11302-013-9399-7] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 10/24/2013] [Indexed: 12/16/2022] Open
Abstract
There are multiple roles for purinergic signalling in both male and female reproductive organs. ATP, released as a cotransmitter with noradrenaline from sympathetic nerves, contracts smooth muscle via P2X1 receptors in vas deferens, seminal vesicles, prostate and uterus, as well as in blood vessels. Male infertility occurs in P2X1 receptor knockout mice. Both short- and long-term trophic purinergic signalling occurs in reproductive organs. Purinergic signalling is involved in hormone secretion, penile erection, sperm motility and capacitation, and mucous production. Changes in purinoceptor expression occur in pathophysiological conditions, including pre-eclampsia, cancer and pain.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF, UK,
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Rebello MR, Medler KF. Ryanodine receptors selectively contribute to the formation of taste-evoked calcium signals in mouse taste cells. Eur J Neurosci 2010; 32:1825-35. [PMID: 20955474 DOI: 10.1111/j.1460-9568.2010.07463.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The peripheral taste system uses multiple signaling pathways to transduce a stimulus into an output signal that activates afferent neurons. All of these signaling pathways depend on transient increases in intracellular calcium, but current understanding of these calcium signals is not well developed. Using molecular and physiological techniques, this study establishes that ryanodine receptors (RyRs), specifically isoform 1, are expressed in taste cells and that their physiological function differs among cell types employing different signaling pathways. RyR1 contributes to some taste-evoked signals that rely on calcium release from internal stores but can also supplement the calcium signal that is initiated by opening voltage-gated calcium channels. In taste cells expressing both signaling pathways, RyR1 contributes to the depolarization-induced calcium signal but not to the calcium signal that depends on calcium release from stores. These data suggest that RyR1 is an important regulator of calcium signaling and that its physiological role in taste cells is dictated by the nature of the calcium signaling mechanisms expressed.
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Affiliation(s)
- Michelle R Rebello
- Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA
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Costa RR, Varanda WA, Franci CR. A calcium-induced calcium release mechanism supports luteinizing hormone-induced testosterone secretion in mouse Leydig cells. Am J Physiol Cell Physiol 2010; 299:C316-23. [DOI: 10.1152/ajpcell.00521.2009] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Leydig cells are responsible for the synthesis and secretion of testosterone, processes controlled by luteinizing hormone (LH). Binding of LH to a G protein-coupled receptor in the plasma membrane results in an increase in cAMP and in intracellular Ca2+ concentration ([Ca2+]i). Here we show, using immunofluorescence, that Leydig cells express ryanodine receptors (RyRs) and inositol 1,4,5-trisphosphate receptors (IP3Rs). Measurements of intracellular calcium changes using the fluorescent calcium-sensitive dye fluo-3 and confocal microscopy show that both types of receptors are involved in a calcium-induced calcium release (CICR) mechanism, which amplifies the initial Ca2+ influx through plasma membrane T-type calcium channels (CaV3). The RyRs and IP3Rs are functional, as judged from both their activation by caffeine and IP3 and block by ryanodine and 2-aminoethoxydiphenyl borate (2-APB), respectively. RyRs are the principal players involved in the release of Ca2+ from the endoplasmic reticulum, as evidenced by the fact that global Ca2+ changes evoked by LH are readily blocked by 100 μM ryanodine but not by 2-APB or xestospongin C. Finally, steroid production by Leydig cells is inhibited by ryanodine but not by 2-APB. These results not only broaden our understanding of the role played by calcium in Leydig cells but also show, for the first time, that RyRs have an important role in determining testosterone secretion by the testis.
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Affiliation(s)
- Roberta Ribeiro Costa
- Department of Physiology, School of Medicine of Ribeirão Preto/University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Wamberto Antonio Varanda
- Department of Physiology, School of Medicine of Ribeirão Preto/University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Celso Rodrigues Franci
- Department of Physiology, School of Medicine of Ribeirão Preto/University of São Paulo, Ribeirão Preto, São Paulo, Brazil
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Vázquez-Martínez O, Loranca A, Palma-Tirado L, Wischin-Fuentes S, Villalobos-Leal M, Antaramián A, Riesgo-Escovar J, Hernández-Muñoz R, Díaz-Muñoz M. Time course of retinal degeneration associated with the absence of 1, 4, 5-inositol trisphosphate receptor in Drosophila melanogaster. Exp Biol Med (Maywood) 2010; 235:365-72. [DOI: 10.1258/ebm.2009.009300] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The absence of the inositol trisphosphate receptor is associated with a gradual retinal degeneration in Drosophila melanogaster. To characterize the time-course profile of this process, mosaic flies expressing a null allele of the itp gene in the eye were studied by electroretinograms and electronic microscopy. Membrane contour alterations, disrupted mitochondria, altered morphology and even loss of photoreceptors were increased progressively starting 5 d after hatching, were more evident during days 10–15 and promoted highly disorganized structures thereafter. The synaptic transmission and membrane potential of retinal cells were also significantly distorted, showing reduced ON and OFF transients as well as membrane potential from day 10 of hatching, and the functional defects became progressively more severe. Unexpectedly, these alterations were detected not only in the non-pigmented mutant ommatidia, but also in the pigmented ommatidia, including heterozygous and twin clones expressing 1, 4, 5-inositol trisphosphate receptor (IP3R). To explore the mechanism underlying this degenerative process, the progression of pro-oxidant and apoptotic reactions was characterized by immunohistochemical techniques. Mutant ommatidia showed intermittent episodes of increased pro-oxidant reactions (detected as adducts of 4-hydroxy-nonenal) throughout the fly's life. Similarly, several episodes of active caspase 3, an apoptotic effector, were evident with the same time pattern. Episodes of enhanced lipid peroxidation and apoptosis were also observed in the pigmented ommatidia of the mosaic eyes. The results indicate that photoreceptors lacking IP3R suffer episodes of increased lipid peroxidation, which eventually perturb the retinal subcellular organization and disrupt the phototransduction process and cell viability. Pigmented ommatidia also showed a similar pattern of damage, indicating that the degenerative process is non-autonomous and is so intense that it propagated to the non-mutant retinal cells in the mosaic eyes. In conclusion, ommatidia with a null mutation of IP3R degenerate by a process associated with intermittent lipid peroxidation and apoptotic activities.
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Affiliation(s)
- Olivia Vázquez-Martínez
- Instituto de Neurobiología, Km 15 Carretera QRO-SLP, Campus UNAM-Juriquilla, Querétaro 76230
| | - Angélica Loranca
- Instituto de Neurobiología, Km 15 Carretera QRO-SLP, Campus UNAM-Juriquilla, Querétaro 76230
| | - Lourdes Palma-Tirado
- Instituto de Neurobiología, Km 15 Carretera QRO-SLP, Campus UNAM-Juriquilla, Querétaro 76230
| | - Sabina Wischin-Fuentes
- Instituto de Neurobiología, Km 15 Carretera QRO-SLP, Campus UNAM-Juriquilla, Querétaro 76230
| | - Mónica Villalobos-Leal
- Instituto de Neurobiología, Km 15 Carretera QRO-SLP, Campus UNAM-Juriquilla, Querétaro 76230
| | - Anaid Antaramián
- Instituto de Neurobiología, Km 15 Carretera QRO-SLP, Campus UNAM-Juriquilla, Querétaro 76230
| | - Juan Riesgo-Escovar
- Instituto de Neurobiología, Km 15 Carretera QRO-SLP, Campus UNAM-Juriquilla, Querétaro 76230
| | - Rolando Hernández-Muñoz
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - Mauricio Díaz-Muñoz
- Instituto de Neurobiología, Km 15 Carretera QRO-SLP, Campus UNAM-Juriquilla, Querétaro 76230
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Wang J, Jiang L, Gao X, Ding H, Wang Q, Cheng J, Gao R, Xiao H. Fenvalerate-induced Ca2+ transients via both intracellular and extracellular way in mouse GC-2spd (ts) cells. Toxicology 2009; 259:122-32. [DOI: 10.1016/j.tox.2009.02.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2008] [Revised: 02/19/2009] [Accepted: 02/19/2009] [Indexed: 11/28/2022]
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15
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Saldaña C, Garay E, Rangel GE, Reyes LM, Arellano RO. Native ion current coupled to purinergic activation via basal and mechanically induced ATP release in Xenopus follicles. J Cell Physiol 2008; 218:355-65. [PMID: 18932209 DOI: 10.1002/jcp.21611] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Xenopus follicle-enclosed oocytes are endowed with purinergic receptors located in the follicular cell membrane; their stimulation by ATP elicits an electrical response that includes generation of a fast inward current (F(Cl)) carried by Cl(-). Here, it was found that mechanical stimulation of the follicle provoked a native electrical response named I(mec). This was dependent on coupling between oocyte and follicular cells, because I(mec) was eliminated by enzymatic defolliculation or application of uncoupling drugs, such as heptanol or carbenoxolone. Moreover, the characteristics of I(mec) suggested that it corresponded with opening of the Cl(-) channel involved in F(Cl). For example, I(mec) showed cross-talk with the membrane mechanism that activates the F(Cl) response and anionic selectivity similar to that displayed by F(Cl). Also like F(Cl), I(mec) was independent of extracellular or intracellular Ca(2+). Furthermore, I(mec) was inhibited by superfusion with a purinergic antagonist, suramin, or by an enzyme that rapidly hydrolyzes ATP, apyrase. The response to mechanical stimulation was reconstituted in defolliculated oocytes expressing P2X channels as an ATP sensor. Recently, it has been shown that ATP release from the Xenopus oocyte is triggered by mechanical stimulation. Together, these observations seemed to indicate that I(mec) is activated through a mechanism that involves oocyte release of ATP that diffuses and activates purinergic receptors in follicular cells, with subsequent opening of F(Cl) channels. Thus, I(mec) generation disclosed a paracrine communication system via ATP between the oocyte and its companion follicular cells that might be of physiological importance during the growth and development of the gamete.
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Affiliation(s)
- Carlos Saldaña
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, Mexico
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16
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Díaz-Muñoz M, de la Rosa Santander P, Juárez-Espinosa AB, Arellano RO, Morales-Tlalpan V. Granulosa cells express three inositol 1,4,5-trisphosphate receptor isoforms: cytoplasmic and nuclear Ca2+ mobilization. Reprod Biol Endocrinol 2008; 6:60. [PMID: 19068129 PMCID: PMC2631483 DOI: 10.1186/1477-7827-6-60] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Accepted: 12/09/2008] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Granulosa cells play an important endocrine role in folliculogenesis. They mobilize Ca2+ from intracellular stores by a coordinated action between 1,4,5 inositol trisphosphate and ryanodine receptors (IP3R and RyR). The aim of this study was to explore the isoforms of IP3Rs expressed in mouse C57BL/6 NHsd granulosa cells, characterizing their intranuclear localization and the relation with other Ca2+-handling proteins. METHODS Ovarian tissue and granulosa cells were analyzed by multiphotonic and confocal microscopy to determine the intracellular presence of IP3R types 1, 2 and 3, RyR, thapsigargin-sensitive Ca2+-ATPase, and endomembranes. Cellular fractionation and Western blot assays were also used to further confirm the nuclear occurrence of the three IP3R isoforms. Free nuclear and cytosolic Ca2+ concentrations were measured using Fluo-4 AM by confocal microscopy. RESULTS By using antibodies and specific fluorophores, was shown that granulosa cells endomembranes contain three isoforms of IP3R, the RyR, and the thapsigargin-sensitive Ca2+-ATPase (SERCA). Interestingly, all these proteins were also detected in the nuclear envelope and in well-defined intranuclear structures. Microsomal membranes depicted characteristic bands of the 3 types of IP3R, but also variants of lower molecular weight. Analysis of nuclear membranes and nucleoplasmic fraction confirmed the nuclear localization of the IP3R types 1, 2 and 3. We demonstrated ATP-induced Ca2+ transients in the nuclear and cytoplasmic compartments. Remarkably, the inhibitory effect on ATP-induced Ca2+ mobilization of brefeldin A was more accentuated in the cytoplasm than in the nucleus. CONCLUSION These findings provide evidence that granulosa cells, including nuclei, express the Ca2+-handling proteins that allow Ca2+ mobilization. All three IP3R were also detected in ovarian slices, including the nuclei of granulosa cells, suggesting that these cells use the three IP3R in situ to achieve their physiological responses.
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Affiliation(s)
- Mauricio Díaz-Muñoz
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Campus UNAM-Juriquilla, Querétaro 76230, QRO., México
| | - Patricia de la Rosa Santander
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Campus UNAM-Juriquilla, Querétaro 76230, QRO., México
| | - Anna Berenice Juárez-Espinosa
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Campus UNAM-Juriquilla, Querétaro 76230, QRO., México
| | - Rogelio O Arellano
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Campus UNAM-Juriquilla, Querétaro 76230, QRO., México
| | - Verónica Morales-Tlalpan
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Campus UNAM-Juriquilla, Querétaro 76230, QRO., México
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Saldaña C, Díaz-Muñoz M, Antaramián A, González-Gallardo A, García-Solís P, Morales-Tlalpan V. MCF-7 breast carcinoma cells express ryanodine receptor type 1: functional characterization and subcellular localization. Mol Cell Biochem 2008; 323:39-47. [DOI: 10.1007/s11010-008-9962-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2008] [Accepted: 11/13/2008] [Indexed: 11/29/2022]
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Aguilar-Roblero R, Mercado C, Alamilla J, Laville A, Díaz-Muñoz M. Ryanodine receptor Ca2+-release channels are an output pathway for the circadian clock in the rat suprachiasmatic nuclei. Eur J Neurosci 2007; 26:575-82. [PMID: 17686038 DOI: 10.1111/j.1460-9568.2007.05679.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Ryanodine-sensitive intracellular Ca2+ channels (RyRs) are present in suprachiasmatic nuclei (SCN) neurons, but the functions served by these channels are not known. Here we addressed whether mobilization of intracellular Ca2+ stores through the RyRs may be a link between the molecular clock and the firing rate in SCN neurons. Activation of the RyRs by administration of either 1 mM caffeine or 100 nM ryanodine increased the firing frequency, whereas inhibition of RyRs by 10 microM dantrolene or 80 microm ryanodine decreased firing rate. Similar results were obtained in experiments conducted at either midday or midnight. Furthermore, these effects were not mediated by synaptic transmission as blockade of GABA A, AMPA and NMDA receptors did not prevent the excitatory or inhibitory effects induced by either dose of ryanodine on SCN firing. We conclude that gating of RyRs is a key element of the intricate output pathway from the circadian clock within SCN neurons in rats.
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Affiliation(s)
- Raúl Aguilar-Roblero
- Departamento de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Apdo. Postal 70-253, México D.F. 04510, Mexico.
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19
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Shideman CR, Hu S, Peterson PK, Thayer SA. CCL5 evokes calcium signals in microglia through a kinase-, phosphoinositide-, and nucleotide-dependent mechanism. J Neurosci Res 2006; 83:1471-84. [PMID: 16547971 DOI: 10.1002/jnr.20839] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Microglia, the resident macrophages of the CNS, are responsible for the innate immune response in the brain and participate in the pathogenesis of certain neurodegenerative disorders. Chemokines initiate activation and migration of microglia. The beta-chemokine CCL5 induces an elevation in intracellular calcium concentration ([Ca(2+)](i)) in human microglia. Here, we examined the signal transduction pathway linking activation of chemokine receptor CCR5 to an elevation in [Ca(2+)](i) in cultured microglia by using pharmacological approaches in combination with Fura-2-based digital imaging. The CCL5-induced response required Janus kinase (Jak) activity and the stimulation of an inhibitory G protein. Multiple downstream signaling pathways were involved, including phosphatidylinositol 3-kinase (PI3K), Bruton's tyrosine kinase (Btk), and phospholipase C (PLC)-mediated release of Ca(2+) from inositol 1,4,5-trisphosphate (IP(3))-sensitive stores. Activation of both the kinase and the lipase pathways was required for eliciting the Ca(2+) response. However, the majority of the [Ca(2+)](i) increase was derived from sources activated by NAD metabolites. Cyclic ADP-ribose (cADPR) evoked Ca(2+) release from intracellular stores, and ADPR evoked Ca(2+) influx via a nimodipine-sensitive channel. Thus, a multistep cascade couples CCR5 activation to Ca(2+) increases in human microglia. Because changes in [Ca(2+)](i) affect chemotaxis, secretion, and gene expression, pharmacologic modulation of this pathway may alter inflammatory and degenerative processes in the CNS.
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MESH Headings
- Agammaglobulinaemia Tyrosine Kinase
- Calcium/metabolism
- Calcium Channels/drug effects
- Calcium Channels/metabolism
- Calcium Signaling/drug effects
- Calcium Signaling/immunology
- Cells, Cultured
- Chemokine CCL5
- Chemokines, CC/immunology
- Chemokines, CC/metabolism
- Chemokines, CC/pharmacology
- Cyclic ADP-Ribose/metabolism
- Encephalitis/immunology
- Encephalitis/metabolism
- Encephalitis/physiopathology
- GTP-Binding Protein alpha Subunits, Gi-Go/metabolism
- Humans
- Immunity, Innate/immunology
- Immunologic Surveillance/immunology
- Inositol 1,4,5-Trisphosphate/metabolism
- Janus Kinase 1
- Microglia/drug effects
- Microglia/immunology
- Microglia/metabolism
- NAD/metabolism
- Nerve Degeneration/immunology
- Nerve Degeneration/metabolism
- Nerve Degeneration/physiopathology
- Phosphatidylinositol 3-Kinases/metabolism
- Protein-Tyrosine Kinases/metabolism
- Receptors, CCR5/agonists
- Receptors, CCR5/immunology
- Receptors, CCR5/metabolism
- Signal Transduction/drug effects
- Signal Transduction/immunology
- Signal Transduction/physiology
- Type C Phospholipases/metabolism
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Affiliation(s)
- C R Shideman
- Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota, USA
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