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Asiedu K. Neurophysiology of corneal neuropathic pain and emerging pharmacotherapeutics. J Neurosci Res 2024; 102:e25285. [PMID: 38284865 DOI: 10.1002/jnr.25285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 11/12/2023] [Accepted: 12/02/2023] [Indexed: 01/30/2024]
Abstract
The altered activity generated by corneal neuronal injury can result in morphological and physiological changes in the architecture of synaptic connections in the nervous system. These changes can alter the sensitivity of neurons (both second-order and higher-order projection) projecting pain signals. A complex process involving different cell types, molecules, nerves, dendritic cells, neurokines, neuropeptides, and axon guidance molecules causes a high level of sensory rearrangement, which is germane to all the phases in the pathomechanism of corneal neuropathic pain. Immune cells migrating to the region of nerve injury assist in pain generation by secreting neurokines that ensure nerve depolarization. Furthermore, excitability in the central pain pathway is perpetuated by local activation of microglia in the trigeminal ganglion and alterations of the descending inhibitory modulation for corneal pain arriving from central nervous system. Corneal neuropathic pain may be facilitated by dysfunctional structures in the central somatosensory nervous system due to a lesion, altered synaptogenesis, or genetic abnormality. Understanding these important pathways will provide novel therapeutic insight.
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Affiliation(s)
- Kofi Asiedu
- School of Optometry & Vision Science, University of New South Wales, Sydney, New South Wales, Australia
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Alemi H, Wang S, Blanco T, Kahale F, Singh RB, Ortiz G, Musayeva A, Yuksel E, Pang K, Deshpande N, Dohlman TH, Jurkunas UV, Yin J, Dana R. The Neuropeptide α-Melanocyte-Stimulating Hormone Prevents Persistent Corneal Edema following Injury. THE AMERICAN JOURNAL OF PATHOLOGY 2024; 194:150-164. [PMID: 37827217 PMCID: PMC10768537 DOI: 10.1016/j.ajpath.2023.09.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 09/03/2023] [Accepted: 09/12/2023] [Indexed: 10/14/2023]
Abstract
Corneal endothelial cells (CEnCs) regulate corneal hydration and maintain tissue transparency through their barrier and pump function. However, these cells exhibit limited regenerative capacity following injury. Currently, corneal transplantation is the only established therapy for restoring endothelial function, and there are no pharmacologic interventions available for restoring endothelial function. This study investigated the efficacy of the neuropeptide α-melanocyte-stimulating hormone (α-MSH) in promoting endothelial regeneration during the critical window between ocular injury and the onset of endothelial decompensation using an established murine model of injury using transcorneal freezing. Local administration of α-MSH following injury prevented corneal edema and opacity, reduced leukocyte infiltration, and limited CEnC apoptosis while promoting their proliferation. These results suggest that α-MSH has a proregenerative and cytoprotective function on CEnCs and shows promise as a therapy for the prevention and management of corneal endothelial dysfunction.
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Affiliation(s)
- Hamid Alemi
- Laboratory of Corneal Immunology, Transplantation and Regeneration, Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts
| | - Shudan Wang
- Laboratory of Corneal Immunology, Transplantation and Regeneration, Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts
| | - Tomas Blanco
- Laboratory of Corneal Immunology, Transplantation and Regeneration, Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts
| | - Francesca Kahale
- Laboratory of Corneal Immunology, Transplantation and Regeneration, Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts
| | - Rohan B Singh
- Laboratory of Corneal Immunology, Transplantation and Regeneration, Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts
| | - Gustavo Ortiz
- Laboratory of Corneal Immunology, Transplantation and Regeneration, Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts
| | - Aytan Musayeva
- Laboratory of Corneal Immunology, Transplantation and Regeneration, Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts
| | - Erdem Yuksel
- Laboratory of Corneal Immunology, Transplantation and Regeneration, Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts
| | - Kunpeng Pang
- Laboratory of Corneal Immunology, Transplantation and Regeneration, Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts
| | - Neha Deshpande
- Laboratory of Corneal Immunology, Transplantation and Regeneration, Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts
| | - Thomas H Dohlman
- Laboratory of Corneal Immunology, Transplantation and Regeneration, Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts
| | - Ula V Jurkunas
- Laboratory of Corneal Immunology, Transplantation and Regeneration, Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts
| | - Jia Yin
- Laboratory of Corneal Immunology, Transplantation and Regeneration, Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts
| | - Reza Dana
- Laboratory of Corneal Immunology, Transplantation and Regeneration, Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts.
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Michalickova D, Kramarikova I, Ozturk HK, Kucera T, Vacik T, Hrncir T, Kutinova Canova N, Sima M, Slanar O. Detection of galanin receptors in the spinal cord in experimental autoimmune encephalomyelitis. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2023; 167:36-42. [PMID: 35147137 DOI: 10.5507/bp.2022.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 01/28/2022] [Indexed: 11/23/2022] Open
Abstract
AIMS The neuropeptide galanin is a widely distributed neurotransmitter/neuromodulator that regulates a variety of physiological processes and also participates in the regulation of stress responses. The aims of the present study were to investigate the expression of galanin receptors (GalR1, GalR2, GalR3) in the spinal cords in a murine model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE) using qPCR analysis and to determine GalR1 cellular localization (oligodendrocytes, microglia, astrocytes, ependymal cells, and endothelial cells in the capillaries) by immunohistochemistry. METHODS Twelve samples from the EAE group and 14 samples from the control group were analyzed. Spinal cords samples were obtained at the peak of the EAE disease. RESULTS The GalR1 mRNA level was significantly decreased in the EAE mice compared with the controls (P=0.016), whereas the mRNA levels of GalR2 and GalR3 were not significantly different for the EAE and the control mice. No significant correlations were found between the severity of the EAE disease and the mRNA levels of GalR1, GalR2 and GalR3. Immunochemical detection of the GalR1 revealed its expression in the ependymal and endothelial cells. Additionally, a weak GalR1 immunoreactivity was occasionally detected in the oligodendrocytes. CONCLUSION This study provides additional evidence of galanin involvement in EAE pathophysiology, but this has to be further investigated.
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Affiliation(s)
- Danica Michalickova
- Institute of Pharmacology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Czech Republic
| | - Ivana Kramarikova
- Institute of Pharmacology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Czech Republic
| | - Hatice Kubra Ozturk
- Institute of Pharmacology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Czech Republic
| | - Tomas Kucera
- Institute of Histology and Embryology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Czech Republic
| | - Tomas Vacik
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital in Prague, Czech Republic
| | - Tomas Hrncir
- Institute of Microbiology, Czech Academy of Sciences, Novy Hradek, Czech Republic
| | - Nikolina Kutinova Canova
- Institute of Pharmacology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Czech Republic
| | - Martin Sima
- Institute of Pharmacology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Czech Republic
| | - Ondrej Slanar
- Institute of Pharmacology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Czech Republic
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Ortega JT, Parmar T, Jastrzebska B. Galanin receptor 3 - A new pharmacological target in retina degeneration. Pharmacol Res 2023; 188:106675. [PMID: 36693600 PMCID: PMC9918719 DOI: 10.1016/j.phrs.2023.106675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 01/16/2023] [Accepted: 01/20/2023] [Indexed: 01/22/2023]
Abstract
The neuropeptide galanin receptor 3 (GALR3) is a class A G protein-coupled receptor (GPCR) broadly expressed in the nervous system, including the retina. GALR3 is involved in the modulation of immune and inflammatory responses. Tight control of these processes is critical for maintaining homeostasis in the retina and is required to sustain vision. Here, we investigated the role of GALR3 in retina pathologies triggered by bright light and P23H mutation in the rhodopsin (RHO) gene, associated with the activation of oxidative stress and inflammatory responses. We used a multiphase approach involving pharmacological inhibition of GALR3 with its antagonist SNAP-37889 and genetic depletion of GALR3 to modulate the GALR3 signaling. Our in vitro experiments in the retinal pigment epithelium-derived cells (ARPE19) susceptible to all-trans-retinal toxicity indicated that GALR3 could be involved in the cellular stress response to this phototoxic product. Indeed, blocking the GALR3 signaling in Abca4-/-/Rdh8-/- and wild-type Balb/cJ mice, sensitive to bright light-induced retina damage, protected retina health in these mice exposed to light. The retina morphology and function were substantially improved, and stress response processes were reduced in these mouse models compared to the controls. Furthermore, in P23H Rho knock-in mice, a model of retinitis pigmentosa (RP), both pharmacological inhibition and genetic ablation of GALR3 prolonged the survival of photoreceptors. These results indicate that GALR3 signaling contributes to acute light-induced and chronic RP-linked retinopathies. Together, this work provides the pharmacological knowledge base to evaluate GALR3 as a potential target for developing novel therapies to combat retinal degeneration.
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Affiliation(s)
- Joseph T Ortega
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44106, USA
| | - Tanu Parmar
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44106, USA
| | - Beata Jastrzebska
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44106, USA.
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Kiezun J, Kiezun M, Krazinski BE, Paukszto L, Koprowicz-Wielguszewska A, Kmiec Z, Godlewski J. Galanin Receptors (GALR1, GALR2, and GALR3) Immunoexpression in Enteric Plexuses of Colorectal Cancer Patients: Correlation with the Clinico-Pathological Parameters. Biomolecules 2022; 12:biom12121769. [PMID: 36551197 PMCID: PMC9775555 DOI: 10.3390/biom12121769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 11/25/2022] [Accepted: 11/25/2022] [Indexed: 11/29/2022] Open
Abstract
Galanin (GAL) is an important neurotransmitter released by the enteric nervous system (ENS) neurons located in the muscularis externa and submucosa enteric plexuses that acts by binding to GAL receptors 1, 2 and 3 (GALR1, 2 and 3). In our previous studies, the GAL immunoexpression was compared in colorectal cancer (CRC) tissue and the adjacent parts of the large intestine wall including myenteric and submucosal plexuses. Recently we have also found that expression levels of GALR1 and GALR3 proteins are elevated in CRC tissue as compared with their expression in epithelial cells of unchanged mucosa. Moreover, higher GALR3 immunoreactivity in CRC cells correlated with better prognosis of CRC patients. To understand the distribution of GALRs in enteric plexuses distal and close to CRC invasion, in the present study we decided to evaluate GALRs expression within the myenteric and submucosal plexuses located proximally and distally to the cancer invasion and correlated the GALRs expression levels with the clinico-pathological data of CRC patients. The immunohistochemical and immunofluorescent methods showed only slightly decreased immunoexpression of GALR1 and GALR3 in myenteric plexuses close to cancer but did not reveal any correlation in the immunoexpression of all three GAL receptors in myenteric plexuses and tumour progression. No significant changes were found between the expression levels of GALRs in submucosal plexuses distal and close to the tumour. However, elevated GALR1 expression in submucosal plexuses in vicinity of CRC correlated with poor prognosis, higher tumour grading and shorter overall survival. When myenteric plexuses undergo morphological and functional alterations characteristic for atrophy, GALRs maintain or only slightly decrease their expression status. In contrast, the correlation between high expression of GALR1 in the submucosal plexuses and overall survival of CRC patients suggest that GAL and GALRs can act as a components of local neuro-paracrine pro-proliferative pathways accelerating the invasion and metastasis of cancer cell. The obtained results suggest an important role of GALR1 in submucosal plexuses function during the progression of CRC and imply that GALR1 expression in submucosal plexuses of ENS could be an important predictive factor for CRC progression.
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Affiliation(s)
- Jacek Kiezun
- Department of Human Histology and Embryology, School of Medicine, University of Warmia and Mazury in Olsztyn, Warszawska Street 30, 10-082 Olsztyn, Poland
- Correspondence: ; Tel.: +48-89-524-53-06
| | - Marta Kiezun
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Oczapowskiego Street 1a, 10-719 Olsztyn, Poland
| | - Bartlomiej Emil Krazinski
- Department of Human Histology and Embryology, School of Medicine, University of Warmia and Mazury in Olsztyn, Warszawska Street 30, 10-082 Olsztyn, Poland
| | - Lukasz Paukszto
- Department of Botany and Nature Protection, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Plac Łódzki 1, 10-719 Olsztyn, Poland
| | - Anna Koprowicz-Wielguszewska
- Department of Human Histology and Embryology, School of Medicine, University of Warmia and Mazury in Olsztyn, Warszawska Street 30, 10-082 Olsztyn, Poland
| | - Zbigniew Kmiec
- Department of Histology, Faculty of Medicine, Medical University of Gdansk, Sklodowskiej-Curie Street 3a, 80-211 Gdansk, Poland
| | - Janusz Godlewski
- Department of Human Histology and Embryology, School of Medicine, University of Warmia and Mazury in Olsztyn, Warszawska Street 30, 10-082 Olsztyn, Poland
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Puri S, Kenyon BM, Hamrah P. Immunomodulatory Role of Neuropeptides in the Cornea. Biomedicines 2022; 10:1985. [PMID: 36009532 PMCID: PMC9406019 DOI: 10.3390/biomedicines10081985] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/11/2022] [Accepted: 08/12/2022] [Indexed: 12/21/2022] Open
Abstract
The transparency of the cornea along with its dense sensory innervation and resident leukocyte populations make it an ideal tissue to study interactions between the nervous and immune systems. The cornea is the most densely innervated tissue of the body and possesses both immune and vascular privilege, in part due to its unique repertoire of resident immune cells. Corneal nerves produce various neuropeptides that have a wide range of functions on immune cells. As research in this area expands, further insights are made into the role of neuropeptides and their immunomodulatory functions in the healthy and diseased cornea. Much remains to be known regarding the details of neuropeptide signaling and how it contributes to pathophysiology, which is likely due to complex interactions among neuropeptides, receptor isoform-specific signaling events, and the inflammatory microenvironment in disease. However, progress in this area has led to an increase in studies that have begun modulating neuropeptide activity for the treatment of corneal diseases with promising results, necessitating the need for a comprehensive review of the literature. This review focuses on the role of neuropeptides in maintaining the homeostasis of the ocular surface, alterations in disease settings, and the possible therapeutic potential of targeting these systems.
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Affiliation(s)
- Sudan Puri
- Center for Translational Ocular Immunology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA 02111, USA
- Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA 02111, USA
| | - Brendan M. Kenyon
- Center for Translational Ocular Immunology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA 02111, USA
- Program in Neuroscience, Graduate School of Biomedical Sciences, Tufts University, Boston, MA 02111, USA
| | - Pedram Hamrah
- Center for Translational Ocular Immunology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA 02111, USA
- Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA 02111, USA
- Program in Neuroscience, Graduate School of Biomedical Sciences, Tufts University, Boston, MA 02111, USA
- Departments of Immunology and Neuroscience, Tufts University School of Medicine, Boston, MA 02111, USA
- Cornea Service, Tufts New England Eye Center, Boston, MA 02111, USA
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7
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Kiezun J, Godlewski J, Krazinski BE, Kozielec Z, Kmiec Z. Galanin Receptors (GalR1, GalR2, and GalR3) Expression in Colorectal Cancer Tissue and Correlations to the Overall Survival and Poor Prognosis of CRC Patients. Int J Mol Sci 2022; 23:ijms23073735. [PMID: 35409094 PMCID: PMC8998502 DOI: 10.3390/ijms23073735] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 02/23/2022] [Accepted: 03/25/2022] [Indexed: 01/11/2023] Open
Abstract
Colorectal cancer (CRC) is the second most common cause of cancer in women and the third in men. The postoperative pathomorphological evaluation of patients with CRC is extremely important for future therapeutic decisions. Although our previous studies demonstrated high galanin (GAL) presence within tumor tissue and an elevated concentration of GAL in the serum of CRC patients, to date, there is a lack of data regarding GAL receptor (GalR) protein expression in CRC cells. Therefore, the aim of this study was to evaluate the presence of all three types of GalRs (GalR1, GalR2 and GalR3) within epithelial cells of the human colon and CRC tissue with the use of the immunohistochemical method and to correlate the results with the clinical-pathological data. We found stronger immunoreactivity of GalR1 and GalR3 in CRC cells compared to epithelial cells of the unchanged mucosa of the large intestine. No differences in the GalR2 protein immunoreactivity between the studied tissues were noted. We also found that the increased immunoexpression of the GalR3 in CRC tissue correlated with the better prognosis and longer survival (p < 0.0079) of CRC patients (n = 55). The obtained results suggest that GalR3 may play the role of a prognostic factor for CRC patients. Based on data from the TCGA-COAD project deposited in the GDC Data Portal, we also found that GalR mRNA in cancer samples and the adjacent normal tissue did not correlate with immunoexpression of the GalR proteins in CRC cells and epithelial cells of the unchanged mucosa.
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MESH Headings
- Colorectal Neoplasms/genetics
- Female
- Humans
- Male
- RNA, Messenger/metabolism
- Receptor, Galanin, Type 1/metabolism
- Receptor, Galanin, Type 2/genetics
- Receptor, Galanin, Type 2/metabolism
- Receptor, Galanin, Type 3/metabolism
- Receptors, Galanin/genetics
- Receptors, Galanin/metabolism
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Affiliation(s)
- Jacek Kiezun
- Department of Human Histology and Embryology, Faculty of Medical Sciences, University of Warmia and Mazury in Olsztyn, 10-082 Olsztyn, Poland; (J.G.); (B.E.K.)
- Correspondence: ; Tel.: +48-89-524-53-06
| | - Janusz Godlewski
- Department of Human Histology and Embryology, Faculty of Medical Sciences, University of Warmia and Mazury in Olsztyn, 10-082 Olsztyn, Poland; (J.G.); (B.E.K.)
| | - Bartlomiej E. Krazinski
- Department of Human Histology and Embryology, Faculty of Medical Sciences, University of Warmia and Mazury in Olsztyn, 10-082 Olsztyn, Poland; (J.G.); (B.E.K.)
| | - Zygmunt Kozielec
- Department of Pathomorphology, Faculty of Medical Sciences, University of Warmia and Mazury in Olsztyn, 10-561 Olsztyn, Poland;
| | - Zbigniew Kmiec
- Department of Histology, Faculty of Medicine, Medical University of Gdansk, 80-211 Gdansk, Poland;
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Kuipers A, Balaskó M, Pétervári E, Koller A, Brunner SM, Moll GN, Kofler B. Intranasal Delivery of a Methyllanthionine-Stabilized Galanin Receptor-2-Selective Agonist Reduces Acute Food Intake. Neurotherapeutics 2021; 18:2737-2752. [PMID: 34859381 PMCID: PMC8804135 DOI: 10.1007/s13311-021-01155-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/30/2021] [Indexed: 11/27/2022] Open
Abstract
The regulatory (neuro)peptide galanin is widely distributed in the central and peripheral nervous systems, where it mediates its effects via three G protein-coupled receptors (GAL1-3R). Galanin has a vast diversity of biological functions, including modulation of feeding behavior. However, the clinical application of natural galanin is not practicable due to its rapid in vivo breakdown by peptidases and lack of receptor subtype specificity. Much effort has been put into the development of receptor-selective agonists and antagonists, and while receptor selectivity has been attained to some degree, most ligands show overlapping affinity. Therefore, we aimed to develop a novel ligand with specificity to a single galanin receptor subtype and increased stability. To achieve this, a lanthionine amino acid was enzymatically introduced into a galanin-related peptide. The residue's subsequent cyclization created a conformational constraint which increased the peptide's receptor specificity and proteolytic resistance. Further exchange of certain other amino acids resulted in a novel methyllanthionine-stabilized galanin receptor agonist, a G1pE-T3N-S6A-G12A-methyllanthionine[13-16]-galanin-(1-17) variant, termed M89b. M89b has exclusive specificity for GAL2R and a prolonged half-life in serum. Intranasal application of M89b to unfasted rats significantly reduced acute 24 h food intake inducing a drop in body weight. Combined administration of M89b and M871, a selective GAL2R antagonist, abolished the anorexigenic effect of M89b, indicating that the effect of M89b on food intake is indeed mediated by GAL2R. This is the first demonstration of in vivo activity of an intranasally administered lanthipeptide. Consequently, M89b is a promising candidate for clinical application as a galanin-related peptide-based therapeutic.
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Affiliation(s)
- Anneke Kuipers
- Lanthio Health B.V., Rozenburglaan 13B, 9727 DL, Groningen, Netherlands
| | - Márta Balaskó
- Institute for Translational Medicine, Medical School, University of Pécs, 12 Szigeti út, H-7624, Pécs, Hungary
| | - Erika Pétervári
- Institute for Translational Medicine, Medical School, University of Pécs, 12 Szigeti út, H-7624, Pécs, Hungary
| | - Andreas Koller
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Muellner Hauptstr. 48, 5020, Salzburg, Austria
- Research Program for Experimental Ophthalmology, Department of Ophthalmology and Optometry, University Hospital of the Paracelsus Medical University, Salzburg, Austria
| | - Susanne M Brunner
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Muellner Hauptstr. 48, 5020, Salzburg, Austria
- Research Program for Experimental Ophthalmology, Department of Ophthalmology and Optometry, University Hospital of the Paracelsus Medical University, Salzburg, Austria
| | - Gert N Moll
- Lanthio Health B.V., Rozenburglaan 13B, 9727 DL, Groningen, Netherlands
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, Netherlands
| | - Barbara Kofler
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Muellner Hauptstr. 48, 5020, Salzburg, Austria.
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Ruiz-Lozano RE, Hernandez-Camarena JC, Loya-Garcia D, Merayo-Lloves J, Rodriguez-Garcia A. The molecular basis of neurotrophic keratopathy: Diagnostic and therapeutic implications. A review. Ocul Surf 2021; 19:224-240. [DOI: 10.1016/j.jtos.2020.09.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 09/13/2020] [Accepted: 09/22/2020] [Indexed: 12/11/2022]
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10
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Markasz L, Olsson KW, Holmström G, Sindelar R. Cluster Analysis of Early Postnatal Biochemical Markers May Predict Development of Retinopathy of Prematurity. Transl Vis Sci Technol 2020; 9:14. [PMID: 33344058 PMCID: PMC7726592 DOI: 10.1167/tvst.9.13.14] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 10/19/2020] [Indexed: 12/15/2022] Open
Abstract
Purpose Growth factors and inflammatory and angiogenetic proteins are involved in the development of retinopathy of prematurity (ROP). However, no early biochemical markers are in clinical use to predict ROP. By performing cluster analysis of multiple biomarkers, we aimed to determine patient groups with high and low risk for developing ROP. Methods In total, 202 protein markers in plasma were quantified by proximity extension assay from 35 extremely preterm infants on day 2 of life. Infants were sorted in groups by automated two-dimensional hierarchical clustering of all biomarkers. ROP was classified as stages I to III with or without surgical treatment. Predictive biomarkers were evaluated by analysis of variance and detected differences by two-sided paired t-test with Bonferroni corrections for multiple comparisons. Results Differences in 39 biochemical markers divided infants without ROP into two control groups (control 1, n = 7; control 2, n = 5; P < 0.05). Sixty-six biochemical markers defined differences between the control groups (n = 13) and all ROP infants (n = 23; P < 0.05). PARK7, VIM, MPO, CD69, and NEMO were markedly increased in control 1 compared to all ROP infants (P < 0.001). Lower TNFRSF4 and higher HER2 and GAL appeared in infants with ROP as compared to control 1 and/or 2 (P < 0.05, respectively). Conclusions Our data suggest that early elevated levels of PARK7, VIM, MPO, CD69, and NEMO may be associated with lower risk of developing ROP. Lower levels of TNFRSF4 with higher levels of HER2 and GAL may predict ROP development. Translational Relevance Cluster analysis of early postnatal biomarkers may help to identify infants with low or high risk of developing ROP.
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Affiliation(s)
- Laszlo Markasz
- Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden
| | - Karl-Wilhelm Olsson
- Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden.,Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
| | - Gerd Holmström
- Department of Neuroscience/Ophthalmology, Uppsala University, Uppsala, Sweden
| | - Richard Sindelar
- Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden
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Falkenstetter S, Leitner J, Brunner SM, Rieder TN, Kofler B, Weis S. Galanin System in Human Glioma and Pituitary Adenoma. Front Endocrinol (Lausanne) 2020; 11:155. [PMID: 32265844 PMCID: PMC7105811 DOI: 10.3389/fendo.2020.00155] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 03/06/2020] [Indexed: 11/20/2022] Open
Abstract
Expression of neuropeptides and their corresponding receptors has been demonstrated in different cancer types, where they can play a role in tumor cell growth, invasion, and migration. Human galanin (GAL) is a 30-amino-acid regulatory neuropeptide which acts through three G protein-coupled receptors, GAL1-R, GAL2-R, and GAL3-R that differ in their signal transduction pathways. GAL and galanin receptors (GALRs) are expressed by different tumors, and direct involvement of GAL in tumorigenesis has been shown. Despite its strong expression in the central nervous system (CNS), the role of GAL in CNS tumors has not been extensively studied. To date, GAL peptide expression, GAL receptor binding and mRNA expression have been reported in glioma, meningioma, and pituitary adenoma. However, data on the cellular distribution of GALRs are sparse. The aim of the present study was to examine the expression of GAL and GALRs in different brain tumors by immunohistochemistry. Anterior pituitary gland (n = 7), pituitary adenoma (n = 9) and glioma of different WHO grades I-IV (n = 55) were analyzed for the expression of GAL and the three GALRs with antibodies recently extensively validated for specificity. While high focal GAL immunoreactivity was detected in up to 40% of cells in the anterior pituitary gland samples, only one pituitary adenoma showed focal GAL expression, at a low level. In the anterior pituitary, GAL1-R and GAL3-R protein expression was observed in up to 15% of cells, whereas receptor expression was not detected in pituitary adenoma. In glioma, diffuse and focal GAL staining was noticed in the majority of cases. GAL1-R was observed in eight out of nine glioma subtypes. GAL2-R immunoreactivity was not detected in glioma and pituitary adenoma, while GAL3-R expression was significantly associated to high-grade glioma (WHO grade IV). Most interestingly, expression of GAL and GALRs was observed in tumor-infiltrating immune cells, including neutrophils and glioma-associated macrophages/microglia. The presence of GALRs on tumor-associated immune cells, especially macrophages, indicates that GAL signaling contributes to homeostasis of the tumor microenvironment. Thus, our data indicate that GAL signaling in tumor-supportive myeloid cells could be a novel therapeutic target.
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MESH Headings
- Adenoma/genetics
- Adenoma/metabolism
- Adenoma/pathology
- Adolescent
- Adult
- Aged
- Aged, 80 and over
- Biomarkers, Tumor/genetics
- Biomarkers, Tumor/metabolism
- Brain Neoplasms/genetics
- Brain Neoplasms/metabolism
- Brain Neoplasms/pathology
- Child
- Child, Preschool
- Galanin/genetics
- Galanin/metabolism
- Gene Expression Regulation, Neoplastic
- Glioma/genetics
- Glioma/metabolism
- Glioma/pathology
- Humans
- Middle Aged
- Pituitary Neoplasms/genetics
- Pituitary Neoplasms/metabolism
- Pituitary Neoplasms/pathology
- Receptor, Galanin, Type 1/genetics
- Receptor, Galanin, Type 1/metabolism
- Receptor, Galanin, Type 2/genetics
- Receptor, Galanin, Type 2/metabolism
- Receptor, Galanin, Type 3/genetics
- Receptor, Galanin, Type 3/metabolism
- Receptors, Galanin/genetics
- Receptors, Galanin/metabolism
- Young Adult
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Affiliation(s)
- Sarah Falkenstetter
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Salzburg, Austria
| | - Julia Leitner
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Salzburg, Austria
| | - Susanne M. Brunner
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Salzburg, Austria
| | - Tim N. Rieder
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Salzburg, Austria
| | - Barbara Kofler
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Salzburg, Austria
- *Correspondence: Barbara Kofler
| | - Serge Weis
- Division of Neuropathology, Department of Pathology and Neuropathology, Neuromed, School of Medicine Campus, Kepler University Hospital, Johannes Kepler University, Linz, Austria
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12
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Brunner SM, Koller A, Stockinger J, Sternberg F, Leis S, Ernst F, Strasser P, Brodowicz B, Ebner S, Holub BS, Rauch I, Graf K, Lang R, Kofler B. Validation of antibody-based tools for galanin research. Peptides 2019; 120:170009. [PMID: 30196126 DOI: 10.1016/j.peptides.2018.08.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 08/02/2018] [Accepted: 08/22/2018] [Indexed: 12/17/2022]
Abstract
Antibodies are an integral biomedical tool, not only for research but also as therapeutic agents. However, progress can only be made with sensitive and specific antibodies. The regulatory (neuro)peptide galanin and its three endogenous receptors (GAL1-3-R) are widely distributed in the central and peripheral nervous systems, and in peripheral non-neuronal tissues. The galanin system has multiple biological functions, including feeding behavior, pain processing, nerve regeneration and inflammation, to name only a few. Galanin could serve as biomarker in these processes, and therefore its receptors are potential drug targets for various diseases. For that reason, it is of paramount interest to precisely measure galanin peptide levels in tissues and to determine the cellular and subcellular localization of galanin receptors. A plethora of antibodies and antibody-based tools, including radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA) kits, are commercially available to detect galanin and its receptors. However, many of them lack rigorous validation which casts doubt on their specificity. A goal of the present study was to raise awareness of the importance of validation of antibodies and antibody-based tools, with a specific focus on the galanin system. To that end, we tested and report here about commercially available antibodies against galanin and galanin receptors that appear specific to us. Furthermore, we investigated the validity of commercially available galanin ELISA kits. As the tested ELISAs failed to meet the validation requirements, we developed and validated a specific sandwich ELISA which can be used to detect full-length galanin in human plasma.
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Affiliation(s)
- Susanne M Brunner
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Muellner Hauptstraße 48, 5020, Salzburg, Austria.
| | - Andreas Koller
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Muellner Hauptstraße 48, 5020, Salzburg, Austria.
| | - Julia Stockinger
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Muellner Hauptstraße 48, 5020, Salzburg, Austria.
| | - Felix Sternberg
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Muellner Hauptstraße 48, 5020, Salzburg, Austria.
| | - Stefan Leis
- Department of Neurology, Christian Doppler Medical Centre and Centre for Cognitive Neuroscience, University Hospital of the Paracelsus Medical University, Ignaz-Harrer-Straße 79, 5020, Salzburg, Austria.
| | - Florian Ernst
- Department of Neurology, Christian Doppler Medical Centre and Centre for Cognitive Neuroscience, University Hospital of the Paracelsus Medical University, Ignaz-Harrer-Straße 79, 5020, Salzburg, Austria.
| | - Peter Strasser
- University Institute for Medical & Chemical Laboratory Diagnostic, University Hospital of the Paracelsus Medical University, Ignaz-Harrer-Straße 79, 5020, Salzburg, Austria.
| | - Bernhard Brodowicz
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Muellner Hauptstraße 48, 5020, Salzburg, Austria.
| | - Sabine Ebner
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Muellner Hauptstraße 48, 5020, Salzburg, Austria.
| | - Barbara S Holub
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Muellner Hauptstraße 48, 5020, Salzburg, Austria.
| | - Isabella Rauch
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Muellner Hauptstraße 48, 5020, Salzburg, Austria.
| | - Kerstin Graf
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Muellner Hauptstraße 48, 5020, Salzburg, Austria.
| | - Roland Lang
- Department of Dermatology, University Hospital of the Paracelsus Medical University, Muellner Hauptstraße 48, 5020, Salzburg, Austria.
| | - Barbara Kofler
- Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, University Hospital of the Paracelsus Medical University, Muellner Hauptstraße 48, 5020, Salzburg, Austria.
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13
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Galanin is a potent modulator of cytokine and chemokine expression in human macrophages. Sci Rep 2019; 9:7237. [PMID: 31076613 PMCID: PMC6510899 DOI: 10.1038/s41598-019-43704-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Accepted: 04/26/2019] [Indexed: 12/14/2022] Open
Abstract
The regulatory peptide galanin is broadly distributed in the central- and peripheral nervous systems as well as in non-neuronal tissues, where it exerts its diverse physiological functions via three G-protein-coupled receptors (GAL1-3-R). Regulatory peptides are important mediators of the cross-communication between the nervous- and immune systems and have emerged as a focus of new therapeutics for a variety of inflammatory diseases. Studies on inflammatory animal models and immune cells revealed both pro- and anti-inflammatory functions of galanin. Here, we probed specific immune-related functions of the galanin system and found galanin and GAL1-R and GAL2-R mRNA to be expressed in a range of human immune cells. In particular, macrophages displayed differentiation- and polarization-dependent expression of galanin and its receptors. Exposure to exogenous galanin affected the cytokine/chemokine expression profile of macrophages differently, depending on their differentiation and polarization, and mainly modulated the expression of chemokines (CCL2, CCL3, CCL5 and CXCL8) and anti-inflammatory cytokines (TGF-β, IL-10 and IL-1Ra), especially in type-1 macrophages. Cytokine/chemokine expression levels in interferon-gamma- and lipopolysaccharide-polarized macrophages were upregulated whereas in unpolarized macrophages they were downregulated upon galanin treatment for 20 hours. This study illuminates the regulation of important cytokines/chemokines in macrophages by galanin, depending on specific cell activation.
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14
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Sternberg F, Vidali S, Holub BS, Stockinger J, Brunner SM, Ebner S, Koller A, Trost A, Reitsamer HA, Schwarzenbacher D, Lang R, Kofler B. Lack of Galanin Receptor 3 Alleviates Psoriasis by Altering Vascularization, Immune Cell Infiltration, and Cytokine Expression. J Invest Dermatol 2018; 138:199-207. [PMID: 28844939 DOI: 10.1016/j.jid.2017.08.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 07/26/2017] [Accepted: 08/01/2017] [Indexed: 01/30/2023]
Abstract
The neuropeptide galanin is distributed in the central and peripheral nervous systems and in non-neuronal peripheral organs, including the skin. Galanin acts via three G protein-coupled receptors which, except galanin receptor 1, are expressed in various skin structures. The galanin system has been associated with inflammatory processes of the skin and of several other organs. Psoriasis is an inflammatory skin disease with increased neovascularization, keratinocyte hyperproliferation, a proinflammatory cytokine milieu, and immune cell infiltration. In this study, we showed that galanin receptor 3 is present in endothelial cells in human and murine dermal vessels and is co-expressed with nestin in neo-vessels of psoriatic patients. Moreover, in a murine psoriasis model, we showed that C57/BL6 mice lacking galanin receptor 3 display a milder course of psoriasis upon imiquimod treatment, leading to decreased disease severity, delayed neo-vascularization, reduced infiltration of neutrophils, and significantly lower levels of proinflammatory cytokines compared with wild-type mice. In contrast, galanin receptor 2-knockout animals did not differ significantly from wild type mice at both the macroscopic and molecular levels in their inflammatory response to imiquimod treatment. Our data indicate that galanin receptor 3, but not galanin receptor 2, plays an important role in psoriasis-like skin inflammation.
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Affiliation(s)
- Felix Sternberg
- Laura Bassi Centre of Expertise-THERAPEP, Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria
| | - Silvia Vidali
- Laura Bassi Centre of Expertise-THERAPEP, Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria
| | - Barbara S Holub
- Laura Bassi Centre of Expertise-THERAPEP, Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria; Department of Dermatology, Paracelsus Medical University, Salzburg, Austria
| | - Julia Stockinger
- Laura Bassi Centre of Expertise-THERAPEP, Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria
| | - Susanne M Brunner
- Laura Bassi Centre of Expertise-THERAPEP, Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria
| | - Sabine Ebner
- Laura Bassi Centre of Expertise-THERAPEP, Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria
| | - Andreas Koller
- Laura Bassi Centre of Expertise-THERAPEP, Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria
| | - Andrea Trost
- Department of Ophthalmology/Optometry, Research Program Experimental Ophthalmology, Paracelsus Medical University Salzburg, Austria
| | - Herbert A Reitsamer
- Department of Ophthalmology/Optometry, Research Program Experimental Ophthalmology, Paracelsus Medical University Salzburg, Austria
| | - David Schwarzenbacher
- Laura Bassi Centre of Expertise-THERAPEP, Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria
| | - Roland Lang
- Department of Dermatology, Paracelsus Medical University, Salzburg, Austria
| | - Barbara Kofler
- Laura Bassi Centre of Expertise-THERAPEP, Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria.
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15
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Kaser-Eichberger A, Trost A, Strohmaier C, Bogner B, Runge C, Bruckner D, Hohberger B, Jünemann A, Kofler B, Reitsamer HA, Schrödl F. Distribution of the neuro-regulatory peptide galanin in the human eye. Neuropeptides 2017; 64:85-93. [PMID: 27914762 DOI: 10.1016/j.npep.2016.11.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 11/22/2016] [Accepted: 11/22/2016] [Indexed: 02/07/2023]
Abstract
Galanin (GAL) is a neuro-regulatory peptide involved in many physiological and pathophysiological processes. While data of GAL origin/distribution in the human eye are rather fragmentary and since recently the presence of GAL-receptors in the normal human eye has been reported, we here systematically search for sources of ocular GAL in the human eye. Human eyes (n=14) were prepared for single- and double-immunohistochemistry of GAL and neurofilaments (NF). Cross- and flat-mount sections were achieved; confocal laser-scanning microscopy was used for documentation. In the anterior eye, GAL-immunoreactivity (GAL-IR) was detected in basal layers of corneal epithelium, endothelium, and in nerve fibers and keratinocytes of the corneal stroma. In the conjunctiva, GAL-IR was seen throughout all epithelial cell layers. In the iris, sphincter and dilator muscle and endothelium of iris vessels displayed GAL-IR. It was also detected in stromal cells containing melanin granules, while these were absent in others. In the ciliary body, ciliary muscle and pigmented as well as non-pigmented ciliary epithelium displayed GAL-IR. In the retina, GAL-IR was detected in cells associated with the ganglion cell layer, and in endothelial cells of retinal blood vessels. In the choroid, nerve fibers of the choroidal stroma as well as fibers forming boutons and surrounding choroidal blood vessels displayed GAL-IR. Further, the majority of intrinsic choroidal neurons were GAL-positive, as revealed by co-localization-experiments with NF, while a minority displayed NF- or GAL-IR only. GAL-IR was also detected in choroidal melanocytes, as identified by the presence of intracellular melanin-granules, as well as in cells lacking melanin-granules, most likely representing macrophages. GAL-IR was detected in numerous cells and tissues throughout the anterior and posterior eye and might therefore be an important regulatory peptide for many aspects of ocular control. Upcoming studies in diseased tissue will help to clarify the role of GAL in ocular homeostasis.
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Affiliation(s)
- Alexandra Kaser-Eichberger
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, Salzburg, Austria.
| | - Andrea Trost
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, Salzburg, Austria
| | - Clemens Strohmaier
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, Salzburg, Austria
| | - Barbara Bogner
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, Salzburg, Austria
| | - Christian Runge
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, Salzburg, Austria
| | - Daniela Bruckner
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, Salzburg, Austria
| | - Bettina Hohberger
- Dept. of Ophthalmology, University Erlangen-Nuremberg, Erlangen, Germany
| | - Anselm Jünemann
- Dept. of Ophthalmology, University Rostock, Rostock, Germany
| | - Barbara Kofler
- Laura-Bassi Centre of Expertise, THERAPEP, Research Program of Receptor Biochemistry and Tumor Metabolism, Dept. of Pediatrics, Paracelsus Medical University/SALK, Salzburg, Austria
| | - Herbert A Reitsamer
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, Salzburg, Austria; Director of the Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, Salzburg, Austria
| | - Falk Schrödl
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, Salzburg, Austria; Dept. of Anatomy, Paracelsus Medical University, Salzburg, Austria
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