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Fonollosa A, Valcarcel M, Salado C, Pereiro X, Vecino E. Effect of somatostatin on human retinal pigment epithelial cells permeability. Exp Eye Res 2019; 184:15-23. [PMID: 30978347 DOI: 10.1016/j.exer.2019.04.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 03/05/2019] [Accepted: 04/05/2019] [Indexed: 11/28/2022]
Abstract
PURPOSE To assess the effect of somatostatin (SST) on the permeability of human retinal pigment epithelial cells. METHODS We conducted two experiments, exposing cells from human-fetal retinal pigment epithelium (hfRPE) cultures to vascular endothelial growth factor (VEGF), with or without SST pretreatment, in one, and to hypoxic conditions, again with or without SST pretreatment, in the other. The paracellular permeability of hfRPE was assessed by measuring transepithelial electrical resistance (TER) and fluorescein isothiocyanate-sodium (FITC-sodium) flux. Immunochemistry analysis was used to assess the expression of occludin and Zonula occludens-1(ZO-1). RESULTS Both VEGF and hypoxia increased permeability of the hfRPE, as measured by TER and tracer flux, and decreased occludin and ZO-1staining, as measured by immunochemistry. Pretreatment of cultures with SST partially counteracted these effects. CONCLUSIONS Somatostatin may play a role in the regulation of permeability across retinal pigment epithelium. It may act as an anti-permeability factor in the retina through the enhancement of tight junction function.
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Affiliation(s)
- Alex Fonollosa
- Begiker-Ophthalmology Research Group, Department of Ophthalmology, Faculty of Medicine and Nursing, BioCruces Health Research Institute, Cruces Hospital, University of the Basque Country UPV/EHU, Bilbao, Spain; Experimental Ophthalmo-Biology Group, Department Cell Biology and Histology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain.
| | - Maria Valcarcel
- Innoprot SL, Parque Científico y Tecnológico de Bizkaia, Derio, Spain
| | - Clarisa Salado
- Innoprot SL, Parque Científico y Tecnológico de Bizkaia, Derio, Spain
| | - Xandra Pereiro
- Experimental Ophthalmo-Biology Group, Department Cell Biology and Histology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain
| | - Elena Vecino
- Experimental Ophthalmo-Biology Group, Department Cell Biology and Histology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain
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Nocera S, Simon A, Fiquet O, Chen Y, Gascuel J, Datiche F, Schneider N, Epelbaum J, Viollet C. Somatostatin Serves a Modulatory Role in the Mouse Olfactory Bulb: Neuroanatomical and Behavioral Evidence. Front Behav Neurosci 2019; 13:61. [PMID: 31024270 PMCID: PMC6465642 DOI: 10.3389/fnbeh.2019.00061] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 03/12/2019] [Indexed: 11/30/2022] Open
Abstract
Somatostatin (SOM) and somatostatin receptors (SSTR1-4) are present in all olfactory structures, including the olfactory bulb (OB), where SOM modulates physiological gamma rhythms and olfactory discrimination responses. In this work, histological, viral tracing and transgenic approaches were used to characterize SOM cellular targets in the murine OB. We demonstrate that SOM targets all levels of mitral dendritic processes in the OB with somatostatin receptor 2 (SSTR2) detected in the dendrites of previously uncharacterized mitral-like cells. We show that inhibitory interneurons of the glomerular layer (GL) express SSTR4 while SSTR3 is confined to the granule cell layer (GCL). Furthermore, SOM cells in the OB receive synaptic inputs from olfactory cortical afferents. Behavioral studies demonstrate that genetic deletion of SSTR4, SSTR2 or SOM differentially affects olfactory performance. SOM or SSTR4 deletion have no major effect on olfactory behavioral performances while SSTR2 deletion impacts olfactory detection and discrimination behaviors. Altogether, these results describe novel anatomical and behavioral contributions of SOM, SSTR2 and SSTR4 receptors in olfactory processing.
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Affiliation(s)
- Sonia Nocera
- INSERM, UMR 894-Center for Psychiatry and Neuroscience (CPN), Paris, France
- Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Axelle Simon
- INSERM, UMR 894-Center for Psychiatry and Neuroscience (CPN), Paris, France
- Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Oriane Fiquet
- INSERM, UMR 894-Center for Psychiatry and Neuroscience (CPN), Paris, France
- Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Ying Chen
- INSERM, UMR 894-Center for Psychiatry and Neuroscience (CPN), Paris, France
- Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Jean Gascuel
- CNRS UMR 6265—Centre des Sciences du Goût et de l’Alimentation (CSGA), Dijon, France
| | - Frédérique Datiche
- CNRS UMR 6265—Centre des Sciences du Goût et de l’Alimentation (CSGA), Dijon, France
| | - Nanette Schneider
- CNRS UMR 6265—Centre des Sciences du Goût et de l’Alimentation (CSGA), Dijon, France
| | - Jacques Epelbaum
- INSERM, UMR 894-Center for Psychiatry and Neuroscience (CPN), Paris, France
- Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Cécile Viollet
- INSERM, UMR 894-Center for Psychiatry and Neuroscience (CPN), Paris, France
- Université Paris Descartes-Sorbonne Paris Cité, Paris, France
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Hernández C, Simó-Servat O, Simó R. Somatostatin and diabetic retinopathy: current concepts and new therapeutic perspectives. Endocrine 2014; 46:209-14. [PMID: 24627166 DOI: 10.1007/s12020-014-0232-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 02/28/2014] [Indexed: 12/15/2022]
Abstract
Somatostatin (SST) is abundantly produced by the human retina, and the main source is the retinal pigment epithelium (RPE). SST exerts relevant functions in the retina (neuromodulation, angiostatic, and anti-permeability actions) by interacting with SST receptors (SSTR) that are also expressed in the retina. In the diabetic retina, a downregulation of SST production does exist. In this article, we give an overview of the mechanisms by which this deficit of SST participates in the main pathogenic mechanisms involved in diabetic retinopathy (DR): neurodegeneration, neovascularization, and vascular leakage. In view of the relevant SST functions in the retina and the reduction of SST production in the diabetic eye, SST replacement has been proposed as a new target for treatment of DR. This could be implemented by intravitreous injections of SST analogs or gene therapy, but this is an aggressive route for the early stages of DR. Since topical administration of SST has been effective in preventing retinal neurodegeneration in STZ-induced diabetic rats, it seems reasonable to test this new approach in humans. In this regard, the results of the ongoing clinical trial EUROCONDOR will provide useful information. In conclusion, SST is a natural neuroprotective and antiangiogenic factor synthesized by the retina which is downregulated in the diabetic eye and, therefore, its replacement seems a rational approach for treating DR. However, clinical trials will be needed to establish the exact position of targeting SST in the treatment of this disabling complication of diabetes.
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Affiliation(s)
- Cristina Hernández
- Diabetes and Metabolism Research Unit, Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Pg. Vall d'Hebron 119-129.08035, Barcelona, Spain
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Cervia D, Catalani E, Dal Monte M, Casini G. Vascular endothelial growth factor in the ischemic retina and its regulation by somatostatin. J Neurochem 2012; 120:818-29. [DOI: 10.1111/j.1471-4159.2011.07622.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Papadaki T, Tsilimbaris M, Pallikaris I, Thermos K. Somatostatin receptor activation (sst(1) -sst(5) ) differentially influences human retinal pigment epithelium cell viability. Acta Ophthalmol 2010; 88:e228-33. [PMID: 20632998 DOI: 10.1111/j.1755-3768.2010.01945.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
PURPOSE To investigate the differential effects of somatostatin and its receptors (sst(1-5) ) on the viability of cultured human retinal pigment epithelium (hRPE) cells. METHODS MTT [3 (4, 5-dimethylthiazol-2yl)-2, 5 diphenyltetrazolium bromide], APO Percentage(TM) and trypan blue assays were performed to assess the mechanisms via which somatostatin (10(-10) -10(-4) m) and selective receptor (sst(1-5) ) ligands (10(-12) -10(-4) m) affect cell viability. The effect of orthovanadate (phosphatase inhibitor, 10(-7) -10(-5) m) on somatostatin's (10(-5) m) actions was examined, and western blot analysis was employed to determine the presence of ssts and phosphotyrosine phosphatase SHP-1 in human RPE cells. RESULTS Somatostatin and selective ligands for the five somatostatin receptor subtypes (sst(1-5) ) decreased cell viability in a concentration-dependent manner. The observed decrease in cell number was partly because of apoptosis via the activation of sst(1) and sst(5) receptors. Activation of sst(2) , sst(3) and sst(4) receptors led to inhibition of cell growth that did not involve apoptosis, but rather antiproliferative actions. SHP-1 was found in the human RPE cells and sodium orthovanadate reversed somatostatin's actions. CONCLUSIONS This study provides new information regarding the involvement of ssts in human RPE cell viability and suggests that a pathway involving the phosphotyrosine phosphatase may mediate somatostatin's actions.
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Affiliation(s)
- Thekla Papadaki
- Department of Pharmacology, Faculty of Medicine, University of Crete, Crete, Greece
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Somatostatin analogues as therapeutics in retinal disease. Pharmacol Ther 2009; 122:324-33. [DOI: 10.1016/j.pharmthera.2009.03.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Accepted: 03/24/2009] [Indexed: 12/30/2022]
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Cervia D, Martini D, Ristori C, Catalani E, Timperio AM, Bagnoli P, Casini G. Modulation of the neuronal response to ischaemia by somatostatin analogues in wild-type and knock-out mouse retinas. J Neurochem 2008; 106:2224-35. [PMID: 18624922 DOI: 10.1111/j.1471-4159.2008.05556.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Somatostatin acts at five G protein-coupled receptors, sst(1)-sst(5). In mouse ischaemic retinas, the over-expression of sst(2) (as in sst(1) knock-out mice) results in the reduction of cell death and glutamate release. In this study, we reported that, in wild-type retinas, somatostatin, the multireceptor ligand pasireotide and the sst(2) agonist octreotide decreased ischaemia-induced cell death and that octreotide also decreased glutamate release. In contrast, cell death was increased by blocking sst(2) with cyanamide. In sst(2) over-expressing ischaemic retinas, somatostatin analogues increased cell death, and octreotide also increased glutamate release. To explain this reversal of the anti-ischaemic effect of somatostatin agonists in the presence of sst(2) over-expression, we tested sst(2) desensitisation because of internalisation or altered receptor function. We observed that (i) sst(2) was not internalised, (ii) among G protein-coupled receptor kinases (GRKs) and regulators of G protein signalling (RGSs), GRK1 and RGS1 expression increased following ischaemia, (iii) both GRK1 and RGS1 were down-regulated by octreotide in wild-type ischaemic retinas, (iv) octreotide down-regulated GRK1 but not RGS1 in sst(2) over-expressing ischaemic retinas. These results demonstrate that sst(2) activation protects against retinal ischaemia. However, in the presence of sst(2) over-expression sst(2) is functionally desensitised by agonists, possibly because of sustained RGS1 levels.
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Affiliation(s)
- Davide Cervia
- Department of Environmental Sciences, University of Tuscia, Largo dell'Università snc, Viterbo.
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Zeyda T, Hochgeschwender U. Null mutant mouse models of somatostatin and cortistatin, and their receptors. Mol Cell Endocrinol 2008; 286:18-25. [PMID: 18206294 DOI: 10.1016/j.mce.2007.11.029] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2007] [Revised: 08/25/2007] [Accepted: 11/28/2007] [Indexed: 01/08/2023]
Abstract
Somatostatin (somatotropin release inhibitory factor, SRIF) and the related cortistatin (CST) are multifunctional peptide molecules attributed with neurohormone, neurotransmitter/modulator, and autocrine/paracrine actions. The physiological responses of SRIF and CST are mediated by five widely distributed G protein-coupled receptors (sst1-5) which have been implicated in regulating numerous biological processes. Much of the information on the effects of somatostatin has been gained through pharmacological studies with analogs and antagonists. The possibility of targeted mutagenesis in the mouse has resulted, over the last 10 years, in the generation of mouse models which genetically lack somatostatin ligands or receptors. We will review here the mouse models generated, the studies undertaken with them, and what has been learned so far.
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Affiliation(s)
- T Zeyda
- John A. Burns School of Medicine, Honolulu, HI, USA
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Cervia D, Casini G, Bagnoli P. Physiology and pathology of somatostatin in the mammalian retina: a current view. Mol Cell Endocrinol 2008; 286:112-22. [PMID: 18242820 DOI: 10.1016/j.mce.2007.12.009] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2007] [Revised: 10/11/2007] [Accepted: 12/12/2007] [Indexed: 12/30/2022]
Abstract
In the retina, peptidergic signalling participates in multiple circuits of visual information processing. The neuropeptide somatostatin (SRIF) is localised to amacrine cells and, in some instances, in a subset of ganglion cells. The variegated expression patterns of SRIF receptors (sst(1)-sst(5)) and the variety of signalling mechanisms activated by retinal SRIF suggest that this peptide may exert multiple actions on retinal neurons and on retinal physiology, although our current understanding reflects a rather complicated picture. SRIF, mostly through sst(2), may act as a positive factor in the retina by regulating retinal homeostasis and protecting neurons against damage. In this respect, SRIF analogues seem to constitute a promising therapeutic arsenal to cure different retinal diseases, as for instance, ischemic and diabetic retinopathies. However, further investigations are needed not only to fully understand the functional role of the SRIF system in the retina but also to exploit new chemical space for drug-like molecules.
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Affiliation(s)
- Davide Cervia
- Department of Environmental Sciences, University of Tuscia, Viterbo, Italy
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Thermos K. Novel signals mediating the functions of somatostatin: the emerging role of NO/cGMP. Mol Cell Endocrinol 2008; 286:49-57. [PMID: 18384933 DOI: 10.1016/j.mce.2008.02.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2007] [Revised: 02/11/2008] [Accepted: 02/12/2008] [Indexed: 11/16/2022]
Abstract
The neuropeptide somatostatin is a cyclic tetradecapeptide, which is widely distributed in the peripheral and central nervous system. It mediates a plethora of physiological actions and functions as a neurotransmitter, neuromodulator or trophic factor. Somatostatin activates six receptor subtypes that are expressed differentially in different tissues and are coupled to diverse signalling pathways. In order to elucidate the functional role of the individual receptor subtypes, many investigations focused on the assignment of each receptor to a particular signalling pathway. Signalling pathways involving enzyme (adenylate cyclase, phospholipases, phosphatases) and ion channel systems in native and recombinant receptor systems have been extensively studied. A one to one situation (receptor/pathway) has yet to be established, thus justifying the diverse actions of somatostatin. Recently, a NO/cGMP pathway has been shown to mediate the functions of somatostatin and its receptors. This review will present the findings that support the emerging role of NO/cGMP as a novel signal in SRIF's actions in retinal physiology and somatotroph release.
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Affiliation(s)
- Kyriaki Thermos
- University of Crete, Faculty of Medicine, Department of Basic Sciences, Laboratory of Pharmacology, Heraklion, Crete, Greece.
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