1
|
Sánchez ML, Coveñas R. The Galaninergic System: A Target for Cancer Treatment. Cancers (Basel) 2022; 14:3755. [PMID: 35954419 PMCID: PMC9367524 DOI: 10.3390/cancers14153755] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 07/28/2022] [Accepted: 07/29/2022] [Indexed: 12/14/2022] Open
Abstract
The aim of this review is to show the involvement of the galaninergic system in neuroendocrine (phaeochromocytomas, insulinomas, neuroblastic tumors, pituitary tumors, small-cell lung cancer) and non-neuroendocrine (gastric cancer, colorectal cancer, head and neck squamous cell carcinoma, glioma) tumors. The galaninergic system is involved in tumorigenesis, invasion/migration of tumor cells and angiogenesis, and this system has been correlated with tumor size/stage/subtypes, metastasis and recurrence rate. In the galaninergic system, epigenetic mechanisms have been related with carcinogenesis and recurrence rate. Galanin (GAL) exerts both proliferative and antiproliferative actions in tumor cells. GAL receptors (GALRs) mediate different signal transduction pathways and actions, depending on the particular G protein involved and the tumor cell type. In general, the activation of GAL1R promoted an antiproliferative effect, whereas the activation of GAL2R induced antiproliferative or proliferative actions. GALRs could be used in certain tumors as therapeutic targets and diagnostic markers for treatment, prognosis and surgical outcome. The current data show the importance of the galaninergic system in the development of certain tumors and suggest future potential clinical antitumor applications using GAL agonists or antagonists.
Collapse
Affiliation(s)
- Manuel Lisardo Sánchez
- Laboratorio de Neuroanatomía de los Sistema Peptidérgicos (Lab. 14), Instituto de Neurociencias de Castilla y León (INCYL), Universidad de Salamanca, c/Pintor Fernando Gallego 1, 37007 Salamanca, Spain;
| | - Rafael Coveñas
- Laboratorio de Neuroanatomía de los Sistema Peptidérgicos (Lab. 14), Instituto de Neurociencias de Castilla y León (INCYL), Universidad de Salamanca, c/Pintor Fernando Gallego 1, 37007 Salamanca, Spain;
- Grupo GIR USAL: BMD (Bases Moleculares del Desarrollo), University of Salamanca, 37007 Salamanca, Spain
| |
Collapse
|
2
|
Molecular and Cellular Mechanisms of Perineural Invasion in Oral Squamous Cell Carcinoma: Potential Targets for Therapeutic Intervention. Cancers (Basel) 2021; 13:cancers13236011. [PMID: 34885121 PMCID: PMC8656475 DOI: 10.3390/cancers13236011] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 11/23/2021] [Accepted: 11/25/2021] [Indexed: 12/11/2022] Open
Abstract
Simple Summary Squamous cell carcinoma is the most common type of oral cavity cancer. It can spread along and invade nerves in a process called perineural invasion. Perineural invasion can increase the chances of tumor recurrence and reduce survival in patients with oral cancer. Understanding how oral cancer interacts with nerves to facilitate perineural invasion is an important area of research. Targeting key events that contribute to perineural invasion in oral cavity cancer may reduce tumor recurrence and improve survival. In this review, we describe the impact of perineural invasion in oral cancer and the mechanisms that contribute to perineural invasion. Highlighting the key events of perineural invasion is important for the identification and testing of novel therapies for oral cancer with perineural invasion. Abstract The most common oral cavity cancer is squamous cell carcinoma (SCC), of which perineural invasion (PNI) is a significant prognostic factor associated with decreased survival and an increased rate of locoregional recurrence. In the classical theory of PNI, cancer was believed to invade nerves directly through the path of least resistance in the perineural space; however, more recent evidence suggests that PNI requires reciprocal signaling interactions between tumor cells and nerve components, particularly Schwann cells. Specifically, head and neck SCC can express neurotrophins and neurotrophin receptors that may contribute to cancer migration towards nerves, PNI, and neuritogenesis towards cancer. Through reciprocal signaling, recent studies also suggest that Schwann cells may play an important role in promoting PNI by migrating toward cancer cells, intercalating, and dispersing cancer, and facilitating cancer migration toward nerves. The interactions of neurotrophins with their high affinity receptors is a new area of interest in the development of pharmaceutical therapies for many types of cancer. In this comprehensive review, we discuss diagnosis and treatment of oral cavity SCC, how PNI affects locoregional recurrence and survival, and the impact of adjuvant therapies on tumors with PNI. We also describe the molecular and cellular mechanisms associated with PNI, including the expression of neurotrophins and their receptors, and highlight potential targets for therapeutic intervention for PNI in oral SCC.
Collapse
|
3
|
Hökfelt T, Barde S, Xu ZQD, Kuteeva E, Rüegg J, Le Maitre E, Risling M, Kehr J, Ihnatko R, Theodorsson E, Palkovits M, Deakin W, Bagdy G, Juhasz G, Prud’homme HJ, Mechawar N, Diaz-Heijtz R, Ögren SO. Neuropeptide and Small Transmitter Coexistence: Fundamental Studies and Relevance to Mental Illness. Front Neural Circuits 2018; 12:106. [PMID: 30627087 PMCID: PMC6309708 DOI: 10.3389/fncir.2018.00106] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 11/05/2018] [Indexed: 12/31/2022] Open
Abstract
Neuropeptides are auxiliary messenger molecules that always co-exist in nerve cells with one or more small molecule (classic) neurotransmitters. Neuropeptides act both as transmitters and trophic factors, and play a role particularly when the nervous system is challenged, as by injury, pain or stress. Here neuropeptides and coexistence in mammals are reviewed, but with special focus on the 29/30 amino acid galanin and its three receptors GalR1, -R2 and -R3. In particular, galanin's role as a co-transmitter in both rodent and human noradrenergic locus coeruleus (LC) neurons is addressed. Extensive experimental animal data strongly suggest a role for the galanin system in depression-like behavior. The translational potential of these results was tested by studying the galanin system in postmortem human brains, first in normal brains, and then in a comparison of five regions of brains obtained from depressed people who committed suicide, and from matched controls. The distribution of galanin and the four galanin system transcripts in the normal human brain was determined, and selective and parallel changes in levels of transcripts and DNA methylation for galanin and its three receptors were assessed in depressed patients who committed suicide: upregulation of transcripts, e.g., for galanin and GalR3 in LC, paralleled by a decrease in DNA methylation, suggesting involvement of epigenetic mechanisms. It is hypothesized that, when exposed to severe stress, the noradrenergic LC neurons fire in bursts and release galanin from their soma/dendrites. Galanin then acts on somato-dendritic, inhibitory galanin autoreceptors, opening potassium channels and inhibiting firing. The purpose of these autoreceptors is to act as a 'brake' to prevent overexcitation, a brake that is also part of resilience to stress that protects against depression. Depression then arises when the inhibition is too strong and long lasting - a maladaption, allostatic load, leading to depletion of NA levels in the forebrain. It is suggested that disinhibition by a galanin antagonist may have antidepressant activity by restoring forebrain NA levels. A role of galanin in depression is also supported by a recent candidate gene study, showing that variants in genes for galanin and its three receptors confer increased risk of depression and anxiety in people who experienced childhood adversity or recent negative life events. In summary, galanin, a neuropeptide coexisting in LC neurons, may participate in the mechanism underlying resilience against a serious and common disorder, MDD. Existing and further results may lead to an increased understanding of how this illness develops, which in turn could provide a basis for its treatment.
Collapse
Affiliation(s)
- Tomas Hökfelt
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Swapnali Barde
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Zhi-Qing David Xu
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
- Department of Neurobiology, Beijing Key Laboratory of Neural Regeneration and Repair, Beijing Laboratory of Brain Disorders (Ministry of Science and Technology), Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Eugenia Kuteeva
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Joelle Rüegg
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
- The Center for Molecular Medicine, Stockholm, Sweden
- Swedish Toxicology Sciences Research Center, Swetox, Södertälje, Sweden
| | - Erwan Le Maitre
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Mårten Risling
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Jan Kehr
- Pronexus Analytical AB, Solna, Sweden
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Robert Ihnatko
- Department of Clinical Chemistry, Linköping University, Linköping, Sweden
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Elvar Theodorsson
- Department of Clinical Chemistry, Linköping University, Linköping, Sweden
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Miklos Palkovits
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - William Deakin
- Neuroscience and Psychiatry Unit, University of Manchester, Manchester, United Kingdom
| | - Gyorgy Bagdy
- Department of Pharmacodynamics, Semmelweis University, Budapest, Hungary
- MTA-SE Neuropsychopharmacology and Neurochemistry Research Group, Hungarian Academy of Sciences, Semmelweis University, Budapest, Hungary
- NAP 2-SE New Antidepressant Target Research Group, Hungarian Brain Research Program, Semmelweis University, Budapest, Hungary
| | - Gabriella Juhasz
- Neuroscience and Psychiatry Unit, University of Manchester, Manchester, United Kingdom
- Department of Pharmacodynamics, Semmelweis University, Budapest, Hungary
- SE-NAP2 Genetic Brain Imaging Migraine Research Group, Hungarian Brain Research Program, Semmelweis University, Budapest, Hungary
| | | | - Naguib Mechawar
- Douglas Hospital Research Centre, Verdun, QC, Canada
- Department of Psychiatry, McGill University, Montreal, QC, Canada
| | | | - Sven Ove Ögren
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| |
Collapse
|
4
|
Fang P, He B, Shi M, Kong G, Dong X, Zhu Y, Bo P, Zhang Z. The regulative effect of galanin family members on link of energy metabolism and reproduction. Peptides 2015; 71:240-9. [PMID: 26188174 DOI: 10.1016/j.peptides.2015.07.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Revised: 06/27/2015] [Accepted: 07/03/2015] [Indexed: 12/22/2022]
Abstract
It is essential for the species survival that an efficient coordination between energy storage and reproduction through endocrine regulation. The neuropeptide galanin, one of the endocrine hormones, can potently coordinate energy metabolism and the activities of hypothalamic-pituitary-gonadal reproductive axis to adjust synthesis and release of metabolic and reproductive hormones in animals and humans. However, few papers have summarized the regulative effect of the galanin family members on the link of energy storage and reproduction as yet. To address this issue, this review attempts to summarize the current information available about the regulative effect of galanin, galanin-like peptide and alarin on the metabolic and reproductive events, with special emphasis on the interactions between galanin and hypothalamic gonadotropin-releasing hormone, pituitary luteinizing hormone and ovarian hormones. This research line will further deepen our understanding of the physiological roles of the galanin family in regulating the link of energy metabolism and reproduction.
Collapse
Affiliation(s)
- Penghua Fang
- Department of Physiology, Nanjing University of Chinese Medicine Hanlin College, Taizhou 225300, China; Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225001, China
| | - Biao He
- Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225001, China
| | - Mingyi Shi
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou 225001, China; Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225001, China
| | - Guimei Kong
- Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225001, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, China
| | - Xiaoyun Dong
- Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225001, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, China
| | - Yan Zhu
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou 225001, China
| | - Ping Bo
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou 225001, China; Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225001, China.
| | - Zhenwen Zhang
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou 225001, China; Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225001, China.
| |
Collapse
|
5
|
Freimann K, Kurrikoff K, Langel Ü. Galanin receptors as a potential target for neurological disease. Expert Opin Ther Targets 2015. [PMID: 26220265 DOI: 10.1517/14728222.2015.1072513] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
INTRODUCTION Galanin is a 29/30 amino acid long neuropeptide that is widely expressed in the brains of many mammals. Galanin exerts its biological activities through three different G protein-coupled receptors, GalR1, GalR2 and GalR3. The widespread distribution of galanin and its receptors in the CNS and the various physiological and pharmacological effects of galanin make the galanin receptors attractive drug targets. AREAS COVERED This review provides an overview of the role of galanin and its receptors in the CNS, the involvement of the galaninergic system in various neurological diseases and the development of new galanin receptor-specific ligands. EXPERT OPINION Recent advances and novel approaches in migrating the directions of subtype-selective ligand development and chemical modifications of the peptide backbone highlight the importance of the galanin neurochemical system as a potential target for drug development.
Collapse
Affiliation(s)
- Krista Freimann
- a 1 University of Tartu, Institute of Technology , Tartu, Estonia +372 737 4871 ;
| | - Kaido Kurrikoff
- b 2 University of Tartu, Institute of Technology , Tartu, Estonia
| | - Ülo Langel
- c 3 University of Tartu, Institute of Technology , Tartu, Estonia.,d 4 Stockholm University, Arrhenius Laboratories for Natural Science, Department of Neurochemistry , Stockholm, Sweden
| |
Collapse
|
6
|
Martins RST, Pinto PIS, Guerreiro PM, Zanuy S, Carrillo M, Canário AVM. Novel galanin receptors in teleost fish: identification, expression and regulation by sex steroids. Gen Comp Endocrinol 2014; 205:109-20. [PMID: 25016048 DOI: 10.1016/j.ygcen.2014.06.030] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2013] [Revised: 06/24/2014] [Accepted: 06/30/2014] [Indexed: 10/25/2022]
Abstract
In fish, the onset of puberty, the transition from juvenile to sexually reproductive adult animals, is triggered by the activation of pituitary gonadotropin secretion and its timing is influenced by external and internal factors that include the growth/adiposity status of the animal. Kisspeptins have been implicated in the activation of puberty but peripheral signals coming from the immature gonad or associated to the metabolic/nutritional status are also thought to be involved. Therefore we hypothesize the importance of the galinergic system in the brain and testis of pre-pubertal male sea bass as a candidate to translate the signals leading to activation of testicular maturation. Here, the transcripts for four galanin receptors (GALR), named GALR1a, 1b, 2a and 2b, were isolated from European sea bass, Dicentrarchus labrax. Phylogenetic analysis confirmed the previously reported duplication of GALR1 in teleost fish, and unravelled the duplication of GALR2 in teleost fish and in some tetrapod species. Comparison with human showed that the key amino acids involved in ligand binding are present in the corresponding GALR1 and GALR2 orthologs. Transcripts for all four receptors are expressed in brain and testes of adult fish with GALR1a and GALR1b abundant in testes and hardly detected in ovaries. In order to investigate whether GALR1 dimorphic expression was dependent on steroid context we evaluated the effect of 11-ketotestosterone and 17β-estradiol treatments on the receptor expression in brain and testes of pre-pubertal males. Interestingly, steroid treatments had no effect on the expression of GALRs in the brain while in the testes, GALR1a and GALR1b were significantly up regulated by 11KT. Altogether, these results support a role for the galaninergic system, in particular the GALR1 paralog, in fish reproductive function.
Collapse
Affiliation(s)
- Rute S T Martins
- Centre of Marine Sciences (CCMAR), University of Algarve, 8005-139 Faro, Portugal.
| | - Patrícia I S Pinto
- Centre of Marine Sciences (CCMAR), University of Algarve, 8005-139 Faro, Portugal.
| | - Pedro M Guerreiro
- Centre of Marine Sciences (CCMAR), University of Algarve, 8005-139 Faro, Portugal.
| | - Silvia Zanuy
- Institute of Aquaculture Torre de la Sal (IATS-CSIC), 12595 Castellon, Spain.
| | - Manuel Carrillo
- Institute of Aquaculture Torre de la Sal (IATS-CSIC), 12595 Castellon, Spain.
| | - Adelino V M Canário
- Centre of Marine Sciences (CCMAR), University of Algarve, 8005-139 Faro, Portugal.
| |
Collapse
|
7
|
Webling KEB, Runesson J, Bartfai T, Langel Ü. Galanin receptors and ligands. Front Endocrinol (Lausanne) 2012; 3:146. [PMID: 23233848 PMCID: PMC3516677 DOI: 10.3389/fendo.2012.00146] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 11/08/2012] [Indexed: 12/13/2022] Open
Abstract
The neuropeptide galanin was first discovered 30 years ago. Today, the galanin family consists of galanin, galanin-like peptide (GALP), galanin-message associated peptide (GMAP), and alarin and this family has been shown to be involved in a wide variety of biological and pathological functions. The effect is mediated through three GPCR subtypes, GalR1-3. The limited number of specific ligands to the galanin receptor subtypes has hindered the understanding of the individual effects of each receptor subtype. This review aims to summarize the current data of the importance of the galanin receptor subtypes and receptor subtype specific agonists and antagonists and their involvement in different biological and pathological functions.
Collapse
Affiliation(s)
- Kristin E. B. Webling
- Department of Neurochemistry, Arrhenius Laboratories for Natural Science, Stockholm UniversityStockholm, Sweden
- *Correspondence: Kristin E. B. Webling, Department of Neurochemistry, Arrhenius Laboratories for Natural Science, Stockholm University, Svante Arrheniusv. 21A, 10691 Stockholm, Sweden. e-mail:
| | - Johan Runesson
- Department of Neurochemistry, Arrhenius Laboratories for Natural Science, Stockholm UniversityStockholm, Sweden
| | - Tamas Bartfai
- Molecular and Integrative Neurosciences Department, The Scripps Research InstituteLa Jolla, CA, USA
| | - Ülo Langel
- Department of Neurochemistry, Arrhenius Laboratories for Natural Science, Stockholm UniversityStockholm, Sweden
- Institute of Technology, University of TartuTartu, Estonia
| |
Collapse
|
8
|
Sugimoto T, Seki N, Shimizu S, Kikkawa N, Tsukada J, Shimada H, Sasaki K, Hanazawa T, Okamoto Y, Hata A. The galanin signaling cascade is a candidate pathway regulating oncogenesis in human squamous cell carcinoma. Genes Chromosomes Cancer 2009; 48:132-42. [PMID: 18973137 DOI: 10.1002/gcc.20626] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
To identify putative biomarkers in squamous cell carcinoma (SCC), a survey of parallel chromosomal alterations and gene expression studies in 10 SCC cell lines were performed using array-comparative genomic hybridization (CGH) and oligo-microarray techniques. The most frequent changes were gains of 11q13.1-13.3 and losses of 18q12.1-23 in SCC. Furthermore, the expression levels of the sets of genes at both these loci in SCC were measured using microarray analysis. By combining the array-CGH with the microarray data, 10 genes at 11q13.1-13.3 and 6 genes at 18q12.1-23 whose expression correlated with chromosomal alterations were identified. To verify the expression levels of the identified genes, we used expression analysis data derived from our earlier study of clinical specimens. In clinical samples, six genes (GAL, GSTP1, MRPL11, MRPL21, SF3B2, and YIF1A) at 11q13.1-13.3 and one gene (GALR1) at 18q23 showed a significant difference between normal and tumor samples. GAL, coding for the neuropeptide galanin, and GALR1, a galanin receptor, were identified as candidate genes of oncogenesis in SCC. The expression levels of GAL, GALR1, GALR2, and GALR3 were confirmed by real-time PCR. The expression ratio between GAL and GALR1 showed a significant negative correlation. GALR1 is a G-protein-coupled receptor that activates GTP-binding proteins to trigger signaling cascades such as the mitogen-activated protein kinase pathway, and is a well-established mitogenic pathway. This further supports the hypothesis that the genes involved in the GAL signaling cascade are candidates for regulation of oncogenesis in SCC.
Collapse
Affiliation(s)
- Takashi Sugimoto
- Department of Functional Genomics, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Hobson SA, Holmes FE, Kerr NCH, Pope RJP, Wynick D. Mice deficient for galanin receptor 2 have decreased neurite outgrowth from adult sensory neurons and impaired pain-like behaviour. J Neurochem 2006; 99:1000-10. [PMID: 17076662 PMCID: PMC2725756 DOI: 10.1111/j.1471-4159.2006.04143.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Expression of the neuropeptide galanin is markedly up-regulated within the adult dorsal root ganglia (DRG) following peripheral nerve injury. We have previously demonstrated that galanin knockout (Gal-KO) mice have a developmental loss of a subset of DRG neurons. Galanin also plays a trophic role in the adult animal, and the rate of peripheral nerve regeneration and neurite outgrowth is reduced in adult Gal-KO mice. Here we describe the characterization of mice with an absence of GalR2 gene transcription (GalR2-MUT) and demonstrate that they have a 15% decrease in the number of calcitonin gene-related peptide (CGRP) expressing neuronal profiles in the adult DRG, associated with marked deficits in neuropathic and inflammatory pain behaviours. Adult GalR2-MUT animals also have a one third reduction in neurite outgrowth from cultured DRG neurons that cannot be rescued by either galanin or a high-affinity GalR2/3 agonist. Galanin activates extracellular signal-regulated kinase (ERK) and Akt in adult wild-type (WT) mouse DRG. Intact adult DRG from GalR2-MUT animals have lower levels of pERK and higher levels of pAkt than are found in WT controls. These data suggest that a lack of GalR2 activation in Gal-KO and GalR2-MUT animals is responsible for the observed developmental deficits in the DRG, and the decrease in neurite outgrowth in the adult.
Collapse
MESH Headings
- Animals
- Behavior, Animal/physiology
- Blotting, Western
- Extracellular Signal-Regulated MAP Kinases/metabolism
- Genotype
- Immunohistochemistry
- Male
- Mice
- Mice, Knockout
- Neurites/physiology
- Neurons, Afferent/physiology
- Pain/genetics
- Pain/psychology
- Peripheral Nerve Injuries
- Phenotype
- Phosphorylation
- Proto-Oncogene Proteins c-akt/physiology
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Receptor, Galanin, Type 2/genetics
- Receptor, Galanin, Type 2/physiology
- Reverse Transcriptase Polymerase Chain Reaction
- Signal Transduction/genetics
- Signal Transduction/physiology
- Transcription, Genetic
Collapse
Affiliation(s)
- Sally-Ann Hobson
- Departments of Pharmacology and Clinical Science at South Bristol, Bristol University, Bristol, UK
| | - Fiona E. Holmes
- Departments of Pharmacology and Clinical Science at South Bristol, Bristol University, Bristol, UK
| | - Niall C. H. Kerr
- Departments of Pharmacology and Clinical Science at South Bristol, Bristol University, Bristol, UK
| | - Robert J. P. Pope
- Departments of Pharmacology and Clinical Science at South Bristol, Bristol University, Bristol, UK
| | - David Wynick
- Departments of Pharmacology and Clinical Science at South Bristol, Bristol University, Bristol, UK
| |
Collapse
|
10
|
Hilke S, Theodorsson A, Fetissov S, Aman K, Holm L, Hökfelt T, Theodorsson E. Estrogen induces a rapid increase in galanin levels in female rat hippocampal formation − possibly a nongenomic/indirect effect. Eur J Neurosci 2005; 21:2089-99. [PMID: 15869505 DOI: 10.1111/j.1460-9568.2005.04050.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Administration of 17beta-estradiol to ovariectomized rats increased the concentrations of galanin-like immunoreactivity (LI) in the hippocampal formation by 215% (P < 0.001) within 1 h. An increase of 125% (P < 0.05) was observed in the same brain region in the proestrous phase of a normal estrous cycle. Tamoxifen did not block the 17beta-estradiol-induced increase in the concentration of galanin-LI but resulted in a 62% decrease in the hypothalamus within 1 h. In vivo microdialysis in the dorsal hippocampal formation showed a decrease of extracellular galanin-LI (P < 0.001) 1-2 h after treatment with 17beta-estradiol, indicating a decreased release of galanin. For comparison, we studied the concentrations of neuropeptide Y, which were not influenced significantly in any of the regions studied. Taken together our results suggest that 17beta-estradiol inhibits galanin release, presumably from noradrenergic nerve terminals, and primarily via a nongenomic/indirect action, not necessarily involving the classical nuclear receptors ER-alpha or ER-beta. These rapid estrogen-induced changes in galanin release could influence transmitter signalling and plasticity in the hippocampal formation.
Collapse
Affiliation(s)
- Susanne Hilke
- Department of Biomedicine and Surgery, Division of Clinical Chemistry, Faculty of Health Sciences, University Hospital, SE-581 82 Linköping, Sweden.
| | | | | | | | | | | | | |
Collapse
|
11
|
Henson BS, Neubig RR, Jang I, Ogawa T, Zhang Z, Carey TE, D'Silva NJ. Galanin receptor 1 has anti-proliferative effects in oral squamous cell carcinoma. J Biol Chem 2005; 280:22564-71. [PMID: 15767248 DOI: 10.1074/jbc.m414589200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
In the United States, oral cancer accounts for more deaths annually than cervical cancer, leukemias, or Hodgkin's lymphoma. Studies have shown that aberrations of chromosome 18q develop with tumor progression and are associated with significantly decreased survival in head and neck cancer patients. The G-protein-coupled receptor, galanin receptor 1 (GALR1), maps to this region of chromosome 18q. Although the role of GALR1 has been well characterized in neuronal cells, little is known regarding this receptor in non-neuronal cells. In this study, the expression, mitogenic function, and signaling mechanism of GALR1 are investigated in normal and malignant oral epithelial cells. mRNA expression was determined via reverse transcriptase-PCR. Protein quantification was done via immunoblot analysis and enzyme-linked immunosorbent assay. For functional and signaling studies, an inhibitory antibody was generated to the N-terminal ligand binding domain of GALR1. GALR1 protein and mRNA expression and GAL secretion were detected at variable levels in immortalized human oral keratinocytes and human oropharyngeal squamous cell carcinoma cell lines. Upon competitive inhibition of GALR1, proliferation was up-regulated in immortalized and malignant keratinocytes. Furthermore, studies with the inhibitory antibody and U0126, the MAPK inhibitor, show that GALR1 inhibits proliferation in immortalized and malignant keratinocytes by inactivating the MAPK pathway. GALR1s inhibitory effects on proliferation in epithelial cells raises the possibility that inactivation or disregulation of this receptor can lead to uncontrolled proliferation and neoplastic transformation.
Collapse
MESH Headings
- Animals
- Antibodies/chemistry
- Antineoplastic Agents/pharmacology
- Binding, Competitive
- Butadienes/pharmacology
- CHO Cells
- Carcinoma, Squamous Cell/drug therapy
- Carcinoma, Squamous Cell/pathology
- Cell Proliferation/drug effects
- Cell Transformation, Neoplastic
- Cells, Cultured
- Chromosomes, Human, Pair 18
- Cricetinae
- Culture Media, Conditioned/pharmacology
- Enzyme Activation
- Enzyme Inhibitors/pharmacology
- Enzyme-Linked Immunosorbent Assay
- Galanin/chemistry
- Humans
- Immunoblotting
- Keratinocytes/cytology
- Keratinocytes/metabolism
- Ligands
- MAP Kinase Signaling System
- Models, Biological
- Mouth Neoplasms/drug therapy
- Nitriles/pharmacology
- Protein Binding
- Protein Structure, Tertiary
- RNA, Messenger/metabolism
- Receptor, Galanin, Type 1/chemistry
- Receptor, Galanin, Type 1/metabolism
- Receptor, Galanin, Type 2/metabolism
- Receptor, Galanin, Type 3/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Signal Transduction
- Time Factors
- Transfection
- Up-Regulation
Collapse
Affiliation(s)
- Bradley S Henson
- Department of Oral Medicine, Pathology, and Oncology, University of Michigan School of Dentistry, Ann Arbor, 48109-0506, USA
| | | | | | | | | | | | | |
Collapse
|
12
|
|
13
|
Larm JA, Shen PJ, Gundlach AL. Differential galanin receptor-1 and galanin expression by 5-HT neurons in dorsal raphé nucleus of rat and mouse: evidence for species-dependent modulation of serotonin transmission. Eur J Neurosci 2003; 17:481-93. [PMID: 12581166 DOI: 10.1046/j.1460-9568.2003.02471.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Galanin and galanin receptors are widely expressed by neurons in rat brain that either synthesize/release and/or are responsive to, classical transmitters such as gamma-aminobutyric acid, acetylcholine, noradrenaline, histamine, dopamine and serotonin (5-hydroxytryptamine, 5-HT). The dorsal raphé nucleus (DRN) contains approximately 50% of the 5-HT neurons in the rat brain and a high percentage of these cells coexpress galanin and are responsive to exogenous galanin in vitro. However, the precise identity of the galanin receptor(s) present on these 5-HT neurons has not been previously established. Thus, the current study used a polyclonal antibody for the galanin receptor-1 (GalR1) to examine the possible expression of this receptor within the DRN of the rat and for comparative purposes also in the mouse. In the rat, intense GalR1-immunoreactivity (IR) was detected in a substantial population of 5-HT-immunoreactive neurons in the DRN, with prominent receptor immunostaining associated with soma and proximal dendrites. GalR1-IR was also observed in many cells within the adjacent median raphé nucleus. In mouse DRN, neurons exhibited similar levels and distribution of 5-HT-IR to that in the rat, but GalR1-IR was undetectable. Consistent with this, galanin and GalR1 mRNA were also undetectable in mouse DRN by in situ hybridization histochemistry, despite the detection of GalR1 mRNA (and GalR1-IR) in adjacent cells in the periaqueductal grey and other midbrain areas. 5-HT neuron activity in the DRN is primarily regulated via 5-HT1A autoreceptors, via inhibition of adenylate cyclase and activation of inward-rectifying K+ channels. Notably, the GalR1 receptor subtype signals via identical mechanisms and our findings establish that galanin modulates 5-HT neuron activity in the DRN of the rat via GalR1 (auto)receptors. However, these studies also identify important species differences in the relationship between midbrain galanin and 5-HT systems, which should prompt further investigations in relation to comparative human neurochemistry and which have implications for studies of animal models of relevant neurological conditions such as stress, anxiety and depression.
Collapse
Affiliation(s)
- Jari A Larm
- Howard Florey Institute of Experimental Physiology and Medicine, Austin & Repatriation Medical Centre, The University of Melbourne, Victoria, Australia
| | | | | |
Collapse
|
14
|
Jacoby AS, Hort YJ, Constantinescu G, Shine J, Iismaa TP. Critical role for GALR1 galanin receptor in galanin regulation of neuroendocrine function and seizure activity. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 2002; 107:195-200. [PMID: 12487125 DOI: 10.1016/s0169-328x(02)00451-5] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The GALR1 galanin receptor is expressed at high levels within the central nervous system. To determine which specific actions of galanin are mediated by GALR1, we have developed mice with an insertional inactivating mutation within the gene encoding GALR1 (Galr1). Homozygous Galr1-/- mice are viable and capable of breeding. They exhibit no significant difference in growth rate relative to Galr1+/+ controls but have reduced circulating levels of insulin-like growth factor-I (IGF-I) and exhibit spontaneous tonic-clonic seizures. The phenotype of these mice identifies a critical role for GALR1 in neuroendocrine regulation and in mediating the anti-seizure activity of galanin.
Collapse
|
15
|
Abstract
The neuropeptide galanin has a widespread but no means ubiquitous expression pattern in the nervous and endocrine systems. Profound changes in the levels and distribution of the peptide occur in a range of path-physiological situations including nerve injury or damage and alterations in the circulating levels of a number of hormones. There is now a substantial body of work to indicate that galanin plays an important biological role as a regulator of neurotransmitter and hormone release in the adult. The recent generation of mice carrying a loss-of-function mutation within the galanin gene has allowed us new insights into the physiological actions of galanin. In this manuscript we detail three sets of data relating to the major phenotypic effects thus far delineated, putting them in the context of existing published data. These studies demonstrate that galanin acts as a developmental and trophic factor to subsets of neurons in the nervous and neuroendocrine systems.
Collapse
Affiliation(s)
- D Wynick
- University Research Centre for Neuroendocrinology, Bristol University, Marlborough Street, Bristol, BS2 8HW
| | | |
Collapse
|
16
|
Counts SE, Perez SE, Kahl U, Bartfai T, Bowser RP, Deecher DC, Mash DC, Crawley JN, Mufson EJ. Galanin: neurobiologic mechanisms and therapeutic potential for Alzheimer's disease. CNS DRUG REVIEWS 2001; 7:445-70. [PMID: 11830760 PMCID: PMC6741671 DOI: 10.1111/j.1527-3458.2001.tb00210.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The neuropeptide galanin (GAL) is widely distributed in the mammalian CNS. Several lines of evidence suggest that GAL may play a critical role in cognitive processes such as memory and attention through an inhibitory modulation of cholinergic basal forebrain activity. Furthermore, GAL fibers hyperinnervate remaining cholinergic basal forebrain neurons in Alzheimer's disease (AD). This suggests that GAL activity impacts cholinergic dysfunction in advanced AD. Pharmacological and in vitro autoradiographic studies indicate the presence of heterogeneous populations of GAL receptor (GALR) sites in the basal forebrain which bind GAL with both high and low affinity. Interestingly, we have recently observed that GALR binding sites increase in the anterior basal forebrain in late-stage AD. Three G protein-coupled GALRs have been identified to date that signal through a diverse array of effector pathways in vitro, including adenylyl cyclase inhibition and phospholipase C activation. The repertoire and distribution of GALR expression in the basal forebrain remains unknown, as does the nature of GAL and GALR plasticity in the AD basal forebrain. Recently, GAL knockout and overexpressing transgenic mice have been generated to facilitate our understanding of GAL activity in basal forebrain function. GAL knockout mice result in fewer cholinergic basal forebrain neurons and memory deficits. On the other hand, mice overexpressing GAL display hyperinnervation of basal forebrain and memory deficits. These data highlight the need to explore further the putative mechanisms by which GAL signaling might be beneficial or deleterious for cholinergic cell survival and activity within basal forebrain. This information will be critical to understanding whether pharmacological manipulation of GALRs would be effective for the amelioration of cognitive deficits in AD.
Collapse
Affiliation(s)
- Scott E. Counts
- Department of Neurological Sciences, Rush‐Presbyterian‐St. Luke's Medical Center, Chicago, IL, USA
| | - Sylvia E. Perez
- Department of Neurological Sciences, Rush‐Presbyterian‐St. Luke's Medical Center, Chicago, IL, USA
| | - Ulrika Kahl
- Department of Neuropharmacology, The Scripps Research Institute, La Jolla, CA, USA
| | - Tamas Bartfai
- Department of Neuropharmacology, The Scripps Research Institute, La Jolla, CA, USA
| | - Robert P. Bowser
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | | | - Deborah C. Mash
- Department of Neurology, University of Miami School of Medicine, Miami, FL, USA
| | - Jacqueline N. Crawley
- Section on Behavioral Neuropharmacology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Elliott J. Mufson
- Department of Neurological Sciences, Rush‐Presbyterian‐St. Luke's Medical Center, Chicago, IL, USA
| |
Collapse
|
17
|
Jacoby AS, Holmes FE, Hort YJ, Shine J, Iismaa TP. Phenotypic analysis ofGalr1 knockout mice reveals a role for GALR1 galanin receptor in modulating seizure activity but not nerve regeneration. ACTA ACUST UNITED AC 2001. [DOI: 10.1007/bf02446510] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
18
|
Zachariou V, Georgescu D, Kansal L, Merriam P, Picciotto MR. Galanin receptor 1 gene expression is regulated by cyclic AMP through a CREB-dependent mechanism. J Neurochem 2001; 76:191-200. [PMID: 11145992 DOI: 10.1046/j.1471-4159.2001.00018.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The galanin receptor-1 (GalR1) protein belongs to a family of G protein-coupled receptors for the neuropeptide galanin (GalR1, GalR2 and GalR3) distributed throughout the central and peripheral nervous system. Activation of galanin receptors by their ligands results in increased feeding, impaired learning, enhanced opiate analgesia and decreased opiate place preference. We have shown that opiate withdrawal, which is known to increase levels of cAMP in the locus coeruleus (LC), results in an increase in the number of galanin binding sites and the level of GalR1 mRNA in the LC. We have isolated a 3.6-kb fragment 5' of the inititiation codon of the mouse GalR1 gene and generated a series of deletion mutations of this fragment driving expression of luciferase for use in transient transfection assays in PC12 and Cath.a cell lines. Treatment with forskolin, but not dideoxyforskolin, up-regulates GalR1 transcription, likely through elevation of cAMP levels. The region between - 1050 and - 700 base pairs upstream of exon one is necessary both for basal activity of the GalR1 promoter and for forskolin-mediated increases in transcription. The forskolin effect can be blocked by simultaneous mutation of a CRE-like site and a CRE/DRE-like site, but not mutation of either site alone. Gel shift and super-shift experiments demonstrate that the transcription factor CREB can bind to both sites and is likely to be responsible for the cAMP-mediated increase in GalR1 promoter activity. This study provides a molecular mechanism for the increased GalR1 expression in the LC seen following opiate withdrawal.
Collapse
Affiliation(s)
- V Zachariou
- Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut 06508, USA
| | | | | | | | | |
Collapse
|
19
|
Abstract
The neuropeptide galanin, which is widely expressed in brain and peripheral tissues, exerts a broad range of physiological effects. Pharmacological studies using peptide analogues have led to speculation about multiple galanin receptor subtypes. Since 1994, a total of three G-protein-coupled receptor (GPCR) subtypes for galanin have been cloned (GAL1, gal2 and gal3). Potent, selective antagonists are yet to be found for any of the cloned receptors. Major challenges in this field include linking the receptor clones with each of the known physiological actions of galanin and evaluating the evidence for additional galanin receptor subtypes.
Collapse
Affiliation(s)
- T A Branchek
- Synaptic Pharmaceutical Corporation, 215 College Road, Paramus, NJ 07652, USA.
| | | | | | | |
Collapse
|
20
|
Rezaei K, Saar K, Soomets U, Valkna A, Näsman J, Zorko M, Akerman K, Schroeder T, Bartfai T, Langel U. Role of third intracellular loop of galanin receptor type 1 in signal transduction. Neuropeptides 2000; 34:25-31. [PMID: 10688965 DOI: 10.1054/npep.1999.0782] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
To determine the domains essential for G-protein coupling of the human galanin receptor type 1 (GalR1), we have used both GalR1 mutants and synthetic receptor-derived peptides in(125)I-galanin and [(35)S]-GTPgammaS binding studies. Replacement of potential phosphorylation sites by Leu in the third intracellular loop (IC3) of GalR1 did not affect K(D)values for the receptor. Peptides derived form the IC3 loop, and especially the N-terminal part of it were able to increase the rate of [(35)S]-GTPgammaS binding to the trimeric Gialpha1beta1gamma2, but not to Gsalphabeta1gamma2, whereas the peptides corresponding to the IC1 and IC2 loops had no such effect. IC3 loop peptides also inhibited the binding of(125)I-galanin to GalR1 in membranes from Rin m5F cells. Our results suggest that the IC3 loop of GalR1, especially its N-terminal part, defines the coupling of the receptor to the Gialpha1beta1gamma2 protein and consequently, to the signal transduction cascade.
Collapse
MESH Headings
- Amino Acid Sequence
- Amino Acid Substitution
- Animals
- Binding Sites
- Cell Line
- Cell Membrane/metabolism
- GTP-Binding Protein alpha Subunits, Gi-Go/metabolism
- GTP-Binding Protein alpha Subunits, Gs/metabolism
- Galanin/metabolism
- Guanosine 5'-O-(3-Thiotriphosphate)/metabolism
- Humans
- Kinetics
- Leucine
- Models, Molecular
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Peptide Fragments/chemistry
- Peptide Fragments/pharmacology
- Phosphorylation
- Protein Structure, Secondary
- Receptor, Galanin, Type 1
- Receptors, Galanin
- Receptors, Neuropeptide/chemistry
- Receptors, Neuropeptide/metabolism
- Recombinant Proteins/chemistry
- Recombinant Proteins/metabolism
- Signal Transduction/physiology
- Spodoptera
- Transfection
Collapse
Affiliation(s)
- K Rezaei
- Department of Neurochemistry and Neurotoxicology, Stockholm University, Stockholm, S-10691, Sweden
| | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Abstract
The development of a strain of galanin knockout mice has provided confirmation of a neuroendocrine role for galanin, as well as supporting results of previous physiological investigations indicating a role for galanin in analgesia and neuropathic pain, and potentially in neuronal growth and regeneration processes. Whether elevation of galanin expression in neurodegenerative disorders such as Alzheimer's disease represents a survival response or exacerbates functional deficit in afflicted individuals remains to be determined. More detailed analysis of the phenotype of the galanin knockout mouse should provide insights into the physiological role of galanin in memory and learning processes, as well as in hypothalamic function and other aspects of neuroendocrine regulation. Biochemical and molecular cloning efforts have demonstrated that the multiplicity of actions of galanin is matched by complexity in the distribution and regulation of galanin and its receptors. A focus on characterisation of galanin receptors has resulted in the molecular cloning of three receptor subtypes to date. The distribution and functional properties of these receptors have not yet been fully elucidated, currently precluding assignment of discrete functions of galanin to any one receptor subtype. It is not currently possible to reconcile available pharmacological data using analogs of galanin and chimeric peptides in functional assay systems with the pharmacological properties of cloned receptor subtypes. This highlights the value of further knockout approaches targeting galanin receptor subtypes, but also raises the possibility of the existence of additional receptor subtypes that have yet to be cloned, or that receptor activity may be modulated by regulatory molecules that remain to be identified. The development of receptor subtype-specific compounds remains a high priority to advance work in this area. The ability to selectively modulate the many different actions of galanin, through a clearer understanding of receptor structure-function relationships and neuronal distribution, promises to provide important insights into the molecular and cellular basis of galanin action in normal physiology, and may provide lead compounds with therapeutic application in the prevention and treatment of a range of disorders.
Collapse
Affiliation(s)
- T P Iismaa
- Neurobiology Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | | |
Collapse
|
22
|
Abstract
Galanin was first isolated 15 years ago. Diversity of galanin receptors has been suspected from the study of native tissues and functional responses to galanin and galanin-like peptides in vitro and in vivo. The recent application of molecular biologic techniques to clone galanin receptors has extended this diversity. So far, three galanin receptor subtypes, GALR1, GALR2, and GALR3, have been cloned from both human and rat. Their molecular structure, pharmacologic profiles, tissue distribution, and signal transduction properties have been partially elucidated.
Collapse
Affiliation(s)
- T Branchek
- Synaptic Pharmaceutical Corporation, Paramus, New Jersey 07652, USA.
| | | | | |
Collapse
|
23
|
Iismaa TP, Fathi Z, Hort YJ, Iben LG, Dutton JL, Baker E, Sutherland GR, Shine J. Structural organization and chromosomal localization of three human galanin receptor genes. Ann N Y Acad Sci 1998; 863:56-63. [PMID: 9928159 DOI: 10.1111/j.1749-6632.1998.tb10683.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Human galanin receptor subtypes GALR1, GALR2, and GALR3 are encoded by separate genes that are located on human chromosomes 18q23, 17q25.3, and 22q13.1, respectively. The exon:intron organization of the gene encoding GALR2 (GALNR2) and GALR3 (GALNR3) is conserved, with exon 1 encoding the NH2-terminus to the end of transmembrane domain 3 and exon 2 encoding the remainder of the receptor, from the second intracellular loop to the COOH-terminus. This conservation of structural organization is indicative of a common evolutionary origin for GALNR2 and GALNR3. The exon:intron organization of the gene encoding GALR1 (GALNR1) is different from that of GALNR2 and GALNR3, with exon 1 encoding the NH2-terminus to the end of transmembrane domain 5, exon 2 encoding the third intracellular loop, and exon 3 encoding the remainder of the receptor, from transmembrane domain 6 to the COOH-terminus. The structural organization of GALNR1 suggests convergent evolution for this gene and represents a structural organization that is unique among genes encoding G-protein-coupled receptors.
Collapse
MESH Headings
- Amino Acid Sequence
- Chromosome Mapping
- Chromosomes, Human, Pair 17
- Chromosomes, Human, Pair 18
- Chromosomes, Human, Pair 22
- Exons
- Genome, Human
- Humans
- Introns
- Molecular Sequence Data
- Receptors, Galanin
- Receptors, Neuropeptide/genetics
- Sequence Alignment
- Sequence Analysis, DNA
Collapse
Affiliation(s)
- T P Iismaa
- Neurobiology Program, Garvan Institute of Medical Research, St. Vincent's Hospital, Sydney NSW, Australia.
| | | | | | | | | | | | | | | |
Collapse
|
24
|
Engelis A, Mozgis DZ, Pine KA, Shine J, Iismaa TP, Pilmane M. Expression of galanin and the GALR1 galanin receptor subtype in the colon of children with paradoxical fecal incontinence. Ann N Y Acad Sci 1998; 863:425-9. [PMID: 9928190 DOI: 10.1111/j.1749-6632.1998.tb10714.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- A Engelis
- Latvian Medical Academy, State Children's Hospital, Riga, Latvia
| | | | | | | | | | | |
Collapse
|
25
|
Benya RV, Matkowskyj KA, Danilkovich A, Hecht G. Galanin causes Cl- secretion in the human colon. Potential significance of inflammation-associated NF-kappa B activation on galanin-1 receptor expression and function. Ann N Y Acad Sci 1998; 863:64-77. [PMID: 9928160 DOI: 10.1111/j.1749-6632.1998.tb10684.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Galanin is widely distributed in enteric nerves and nerve terminals throughout the gastrointestinal (GI) tract. Within the GI tract galanin is best known for its ability to alter smooth muscle contractility and regulate intestinal motility. However, recent studies also indicate that galanin can modulate epithelial ion transport. We previously showed that epithelial cells lining the human GI tract, including those of colonic origin, express Gal1 galanin receptors (Gal1-R). We herein demonstrate that epithelial cells lining the human colon only express Gal1-R receptors and do not express other galanin receptor subtypes. We previously showed that Gal1-R expression was transcriptionally regulated by the transcription factor NF-kappa B. Consistent with this transcription factor being activated in a number of inflammatory conditions, we show increased colonic Gal1-R expression in patients with colitis due to a variety of causes. To further evaluate the physiology of Gal1-R activation, we studied this receptor expressed by the human colon epithelial cell line T84. Gal1-R activation resulted in a dose-dependent increase in Cl- secretion; whereas infection of T84 cells with pathogens known to activate NF-kappa B augmented Gal1-R expression and Cl- secretion. Thus, galanin acts as a secretagogue in epithelial cells lining the human colon, with alterations in Gal1-R expression possibly playing an important role in the diarrhea associated with various inflammatory processes affecting the GI tract.
Collapse
Affiliation(s)
- R V Benya
- Department of Medicine, University of Illinois at Chicago 60612, USA.
| | | | | | | |
Collapse
|
26
|
Wang S, Ghibaudi L, Hashemi T, He C, Strader C, Bayne M, Davis H, Hwa JJ. The GalR2 galanin receptor mediates galanin-induced jejunal contraction, but not feeding behavior, in the rat: differentiation of central and peripheral effects of receptor subtype activation. FEBS Lett 1998; 434:277-82. [PMID: 9742938 DOI: 10.1016/s0014-5793(98)00957-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The neuropeptide galanin mediates a diverse array of physiological functions through activation of specific receptors. Roles of the three recently cloned galanin receptors (GalRs) in rat intestinal contraction and food intake were examined using GalR-selective ligands and the results were compared with the pharmacological profiles of defined GalRs. The action profile of these ligands in jejunal contraction resembled only that of GalR2 and only a high level of GalR2 mRNA was detected in the tissue, supporting GalR2 as the receptor mediating jejunal contraction. The action profile for food intake in rats excluded GalR2, GalR3 and the putative pituitary galanin receptor as the 'feeding receptor', suggesting that either GalR1 or an unidentified GalR is responsible for mediating this function.
Collapse
Affiliation(s)
- S Wang
- Department of CNS/CV Biological Research, Schering-Plough Research Institute, Kenilworth, NJ 07033, USA.
| | | | | | | | | | | | | | | |
Collapse
|
27
|
Fathi Z, Battaglino PM, Iben LG, Li H, Baker E, Zhang D, McGovern R, Mahle CD, Sutherland GR, Iismaa TP, Dickinson KE, Zimanyi IA. Molecular characterization, pharmacological properties and chromosomal localization of the human GALR2 galanin receptor. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1998; 58:156-69. [PMID: 9685625 DOI: 10.1016/s0169-328x(98)00116-8] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The neuropeptide galanin mediates a diverse spectrum of biological activities by interacting with specific G protein-coupled receptors. We have used homology genomic library screening and polymerase chain reaction (PCR) techniques to isolate both genomic and cDNA clones encoding the human homolog of the recently cloned rat GALR2 galanin receptor. By fluorescence in situ hybridization, the gene encoding human GALR2 (GALNR2) has been localized to chromosome 17q25.3. The two coding exons of the human GALNR2 gene, interrupted by an intron positioned at the end of transmembrane domain III, encode a 387 amino acid G protein-coupled receptor with 87% overall amino acid identity with rat GALR2. In HEK-293 cells stably expressing human GALR2, binding of [125I]porcine galanin is saturable and can be displaced by galanin, amino-terminal galanin fragments and chimeric galanin peptides but not by carboxy-terminal galanin fragments. In HEK-293 cells, human GALR2 couples both to Galphaq/11 to stimulate phospholipase C and increase intracellular calcium levels and to Galphai/o to inhibit forskolin-stimulated intracellular cAMP accumulation. A wide tissue distribution is observed by reverse transcriptase (RT)-PCR analysis, with human GALR2 mRNA being detected in many areas of the human central nervous system as well as in peripheral tissues.
Collapse
MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Cell Line
- Chromosome Mapping
- Chromosomes, Human, Pair 17
- Cloning, Organism
- DNA, Complementary
- GTP-Binding Proteins/metabolism
- Galanin/metabolism
- Humans
- In Situ Hybridization, Fluorescence
- Kinetics
- Molecular Sequence Data
- Phosphatidylinositols/metabolism
- Rats
- Receptors, Galanin
- Receptors, Neuropeptide/biosynthesis
- Receptors, Neuropeptide/genetics
- Receptors, Neuropeptide/metabolism
- Recombinant Proteins/biosynthesis
- Recombinant Proteins/metabolism
- Sequence Alignment
- Sequence Homology, Amino Acid
- Swine
- Transfection
Collapse
Affiliation(s)
- Z Fathi
- Neuroscience Drug Discovery, Bristol-Myers Squibb Pharmaceutical Research Institute, 5 Research Parkway, Wallingford, CT 06492, USA.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Galanin Receptors: Recent Developments and Potential Use as Therapeutic Targets. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 1998. [DOI: 10.1016/s0065-7743(08)61070-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
|