1
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Wang XW, Yuan LJ, Yang Y, Zhang M, Chen WF. IGF-1 inhibits MPTP/MPP +-induced autophagy on dopaminergic neurons through the IGF-1R/PI3K-Akt-mTOR pathway and GPER. Am J Physiol Endocrinol Metab 2020; 319:E734-E743. [PMID: 32865008 DOI: 10.1152/ajpendo.00071.2020] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Autophagy dysfunctions are involved in the pathogenesis of Parkinson's disease (PD). In the present study, we aimed to evaluate the involvement of G protein-coupled estrogen receptor (GPER) in the inhibitory effect of insulin-like growth factor-1 (IGF-1) against excessive autophagy in PD animal and cellular models. 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) treatment significantly induced mouse movement disorder and decreased the protein level of tyrosine hydroxylase (TH) in the substantia nigra (SN) and dopamine (DA) content in striatum. Along with the dopamine neuron injury, we observed significant upregulations of microtubule-associated light chain-3 II (LC3-II) and α-synuclein as well as a downregulation of P62 in MPTP-treated mice. These changes could be restored by IGF-1 pretreatment. Cotreatment with IGF-1R antagonist JB-1 or GPER antagonist G15 could block the neuroprotective effects of IGF-1. 1-Methy-4-phenylpyridinium (MPP+) treatment could also excessively activate autophagy along with the reduction of cell viability in SH-SY5Y cells. IGF-1 could inhibit the neurotoxicity through promoting the phosphorylation of Akt and mammalian target of rapamycin (mTOR), which could also be antagonized by JB-1 or G15. These data suggest that IGF-1 inhibits MPTP/MPP+-induced autophagy on dopaminergic neurons through the IGF-1R/PI3K-Akt-mTOR pathway and GPER.
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Affiliation(s)
- Xiao-Wen Wang
- Department of Physiology, Shandong Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines, Physiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Liang-Jie Yuan
- Department of Physiology, Shandong Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines, Physiology, School of Basic Medicine, Qingdao University, Qingdao, China
- School of Basic Medicine, Shandong First Medical University and Shandong Academy of Medical Sciences, Taian, China
| | - Ye Yang
- Department of Physiology, Shandong Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines, Physiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Mei Zhang
- Department of Physiology, Shandong Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines, Physiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Wen-Fang Chen
- Department of Physiology, Shandong Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines, Physiology, School of Basic Medicine, Qingdao University, Qingdao, China
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2
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Azcoitia I, Barreto GE, Garcia-Segura LM. Molecular mechanisms and cellular events involved in the neuroprotective actions of estradiol. Analysis of sex differences. Front Neuroendocrinol 2019; 55:100787. [PMID: 31513774 DOI: 10.1016/j.yfrne.2019.100787] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 08/27/2019] [Accepted: 09/07/2019] [Indexed: 12/12/2022]
Abstract
Estradiol, either from peripheral or central origin, activates multiple molecular neuroprotective and neuroreparative responses that, being mediated by estrogen receptors or by estrogen receptor independent mechanisms, are initiated at the membrane, the cytoplasm or the cell nucleus of neural cells. Estrogen-dependent signaling regulates a variety of cellular events, such as intracellular Ca2+ levels, mitochondrial respiratory capacity, ATP production, mitochondrial membrane potential, autophagy and apoptosis. In turn, these molecular and cellular actions of estradiol are integrated by neurons and non-neuronal cells to generate different tissue protective responses, decreasing blood-brain barrier permeability, oxidative stress, neuroinflammation and excitotoxicity and promoting synaptic plasticity, axonal growth, neurogenesis, remyelination and neuroregeneration. Recent findings indicate that the neuroprotective and neuroreparative actions of estradiol are different in males and females and further research is necessary to fully elucidate the causes for this sex difference.
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Affiliation(s)
- Iñigo Azcoitia
- Department of Cell Biology, Faculty of Biology, Universidad Complutense de Madrid, 28040 Madrid, Spain; Centro de Investigación Biomédica en Red Fragilidad y Envejecimiento Saludables (CIBERFES), Instituto de Salud Carlos III, Avenida Monforte de Lemos, 3-5, 28029 Madrid, Spain.
| | - George E Barreto
- Department of Biological Sciences, School of Natural Sciences, University of Limerick, Limerick, Ireland.
| | - Luis M Garcia-Segura
- Centro de Investigación Biomédica en Red Fragilidad y Envejecimiento Saludables (CIBERFES), Instituto de Salud Carlos III, Avenida Monforte de Lemos, 3-5, 28029 Madrid, Spain; Instituto Cajal, CSIC, Avenida Doctor Arce 37, 28002 Madrid, Spain.
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3
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Yuan LJ, Wang XW, Wang HT, Zhang M, Sun JW, Chen WF. G protein-coupled estrogen receptor is involved in the neuroprotective effect of IGF-1 against MPTP/MPP +-induced dopaminergic neuronal injury. J Steroid Biochem Mol Biol 2019; 192:105384. [PMID: 31175966 DOI: 10.1016/j.jsbmb.2019.105384] [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: 01/08/2019] [Revised: 03/21/2019] [Accepted: 05/26/2019] [Indexed: 12/20/2022]
Abstract
Insulin-like growth factor-1 (IGF-1), an endogenous peptide, exerts important role in brain development, neurogenesis and neuroprotection. There are accumulating evidence for the interaction of IGF-1 and 17β-estradiol systems. IGF-1/IGF-1 receptor (IGF-1R) signaling has been reported to regulate G-protein estrogen receptor (GPER) expression in cancer cells. Whether GPER is involved in the neuroprotective effect of IGF-1 against MPTP/MPP+-induced dopaminergic neuronal injury remains unclear. We showed that IGF-1 could improve MPTP-induced motor deficits and ameliorate the decreased contents of DA and its metabolites in striatum as well as the loss of TH-IR neurons in the substantia nigra (SN). IGF-1 pretreatment also reversed the changes of Bcl-2 and Bax protein expressions in SN in MPTP mice. These effects were abolished by IGF-1 receptor (IGF-1R) antagonist JB-1 or GPER antagonist G15 except the inhibitory effect of G15 on Bax protein expression. Moreover, IGF-1 pretreatment enhanced cell survival against MPP+-induced neurotoxicity in SH-SY5Y cells. IGF-1 exerted anti-apoptotic effects by restoring MPP+-induced changes of Bcl-2 and Bax protein expressions as well as mitochondria membrane potential. Co-treatment with JB-1 or G15 could block these effects. Furthermore, IGF-1 regulated the protein expression of GPER through activation of phosphatidylinositol 3-kinase (PI3-K) and mitogen-activated protein kinase (MAPK) signaling pathways. Overall, we show for the first time that GPER may contribute to the neuroprotective effects of IGF-1 against MPTP/MPP+-induced dopaminergic neuronal injury.
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MESH Headings
- 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine/adverse effects
- Animals
- Behavior, Animal/drug effects
- Disease Models, Animal
- Dopaminergic Neurons/drug effects
- Dopaminergic Neurons/metabolism
- Dopaminergic Neurons/pathology
- Humans
- Insulin-Like Growth Factor I/pharmacology
- Male
- Mice
- Mice, Inbred C57BL
- Neuroblastoma/etiology
- Neuroblastoma/metabolism
- Neuroblastoma/pathology
- Neuroblastoma/prevention & control
- Neuroprotective Agents/pharmacology
- Neurotoxins/adverse effects
- Parkinson Disease/etiology
- Parkinson Disease/metabolism
- Parkinson Disease/pathology
- Parkinson Disease/prevention & control
- Receptors, Estrogen/genetics
- Receptors, Estrogen/metabolism
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Signal Transduction/drug effects
- Tumor Cells, Cultured
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Affiliation(s)
- Liang-Jie Yuan
- Department of Physiology and Pathophysiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao, 266071, China; School of Basic Medicine, Shandong First Medical University (Taishan Medical University), Taian, China
| | - Xiao-Wen Wang
- Department of Physiology and Pathophysiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao, 266071, China
| | - Hao-Tian Wang
- Department of Physiology and Pathophysiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao, 266071, China
| | - Mei Zhang
- Department of Physiology and Pathophysiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao, 266071, China
| | - Jia-Wen Sun
- Department of Physiology and Pathophysiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao, 266071, China
| | - Wen-Fang Chen
- Department of Physiology and Pathophysiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao, 266071, China.
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4
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Williamson TT, Ding B, Zhu X, Frisina RD. Hormone replacement therapy attenuates hearing loss: Mechanisms involving estrogen and the IGF-1 pathway. Aging Cell 2019; 18:e12939. [PMID: 30845368 PMCID: PMC6516159 DOI: 10.1111/acel.12939] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 12/18/2018] [Accepted: 01/06/2019] [Indexed: 12/14/2022] Open
Abstract
Estradiol (E) is a multitasking hormone that plays a prominent role in the reproductive system, and also contributes to physiological and growth mechanisms throughout the body. Frisina and colleagues have previously demonstrated the beneficial effects of this hormone, with E‐treated subjects maintaining low auditory brainstem response (ABR) thresholds relative to control subjects (Proceedings of the National Academy of Sciences of the United States of America, 2006;103:14246; Hearing Research, 2009;252:29). In the present study, we evaluated the functionality of the peripheral and central auditory systems in female CBA/CaJ middle‐aged mice during and after long‐term hormone replacement therapy (HRT) via electrophysiological and molecular techniques. Surprisingly, there are very few investigations about the side effects of HRT in the auditory system after it has been discontinued. Our results show that the long‐term effects of HRT are permanent on ABR thresholds and ABR gap‐in‐noise (GIN) amplitude levels. E‐treated animals had lower thresholds and higher amplitude values compared to other hormone treatment subject groups. Interestingly, progesterone (P)‐treated animals had ABR thresholds that increased but amplitude levels that remained relatively the same throughout treatment. These results were consistent with qPCR experiments that displayed high levels of IGF‐1R in the stria vascularis (SV) of both E and P animal groups compared to combination treatment (E + P) animals. IGF‐1R plays a vital role in mediating anti‐apoptotic responses via the PI3K/AKT pathway. Overall, our findings gain insights into the neuro‐protective properties of E hormone treatments as well as expand the scientific knowledge base to help women decide whether HRT is the right choice for them.
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Affiliation(s)
- Tanika T. Williamson
- Departments of Chemical & Biomedical and Medical Engineering, Global Center for Hearing & Speech Research University of South Florida Tampa Florida
| | - Bo Ding
- Departments of Communication Sciences & Disorders, Global Center for Hearing & Speech Research University of South Florida Tampa Florida
| | - Xiaoxia Zhu
- Departments of Chemical & Biomedical and Medical Engineering, Global Center for Hearing & Speech Research University of South Florida Tampa Florida
| | - Robert D. Frisina
- Departments of Chemical & Biomedical and Medical Engineering, Global Center for Hearing & Speech Research University of South Florida Tampa Florida
- Departments of Communication Sciences & Disorders, Global Center for Hearing & Speech Research University of South Florida Tampa Florida
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5
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Taylor MA, Kan HL, Gollapudi BB, Marty MS. An in vitro developmental neurotoxicity screening assay for retinoic acid-induced neuronal differentiation using the human NT2/D1 cell line. Neurotoxicology 2019; 73:258-264. [PMID: 30980846 DOI: 10.1016/j.neuro.2019.04.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Revised: 03/04/2019] [Accepted: 04/08/2019] [Indexed: 10/27/2022]
Abstract
Traditional approaches (e.g., neurobehavior, neuropathology) can detect alterations in apical endpoints indicative of developmental neurotoxicity (DNT). However, there is an increasing desire to understand mode-of-action (MOA) for DNT effects; thus, this short communication describes initial work on a neuronal differentiation assay. Basically, our laboratory used the human NT2/D1 cell line to develop an assay to evaluate toxicants for effects on all-trans retinoic acid (RA)-induced neuronal differentiation. Based on literature reports, we selected a neuronal protein, neuronal class III β-tubulin (β3-tubulin), as a marker of differentiation. For this assay, cultured RA-treated NT2 cells were trypsinized to individual cells, methanol fixed, and labeled with a β3-tubulin specific monoclonal antibody (TUJ1). Characterization studies using 100,000 cells/sample showed that NT2 cells had appreciable expression of β3-tubulin starting around day 7 of the differentiation process with a peak expression noted around day 12. Methylmercury, 22(R)-hydroxycholesterol, N-(4-hydroxyphenol)retinamide (4HPR), and 9-cis retinoic acid were selected as initial test compounds. Of these, only 9-cis RA, which is known to affect the RA pathway, was positive for specific impacts on differentiation. These results demonstrate the feasibility of using a flow cytometry method targeting specific cellular biomarkers for evaluating effects on neuronal differentiation. Additional assays are needed to detect compounds targeting other (non-RA) neuronal differentiation pathways. Ultimately, a battery of in vitro assays would be needed to evaluate the potential MOAs involved in altered neuronal differentiation.
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Affiliation(s)
| | - H Lynn Kan
- The Dow Chemical Company, Midland, MI, USA
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6
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Zsarnovszky A, Kiss D, Jocsak G, Nemeth G, Toth I, Horvath TL. Thyroid hormone- and estrogen receptor interactions with natural ligands and endocrine disruptors in the cerebellum. Front Neuroendocrinol 2018; 48:23-36. [PMID: 28987779 DOI: 10.1016/j.yfrne.2017.10.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 09/06/2017] [Accepted: 10/04/2017] [Indexed: 10/18/2022]
Abstract
Although the effects of phytoestrogens on brain function is widely unknown, they are often regarded as "natural" and thus as harmless. However, the effects of phytoestrogens or environmental pollutants on brain function is underestimated. Estrogen (17beta-estradiol, E2) and thyroid hormones (THs) play pivotal roles in brain development. In the mature brain, these hormones regulate metabolism on cellular and organismal levels. Thus, E2 and THs do not only regulate the energy metabolism of the entire organism, but simultaneously also regulate important homeostatic parameters of neurons and glia in the CNS. It is, therefore, obvious that the mechanisms through which these hormones exert their effects are pleiotropic and include both intra- and intercellular actions. These hormonal mechanisms are versatile, and the experimental investigation of simultaneous hormone-induced mechanisms is technically challenging. In addition, the normal physiological settings of metabolic parameters depend on a plethora of interactions of the steroid hormones. In this review, we discuss conceptual and experimental aspects of the gonadal and thyroid hormones as they relate to in vitro models of the cerebellum.
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Affiliation(s)
- Attila Zsarnovszky
- Department of Animal Physiology and Animal Health, Faculty of Agricultural and Environmental Sciences, Szent István University, Páter Károly u. 1, H-2100 Gödöllő, Hungary; Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT, USA.
| | - David Kiss
- Departments of Physiology and Biochemistry, University of Veterinary Medicine, Budapest 1078, Hungary
| | - Gergely Jocsak
- Departments of Physiology and Biochemistry, University of Veterinary Medicine, Budapest 1078, Hungary
| | - Gabor Nemeth
- Department of Obstetrics and Gynecology, University of Szeged, School of Medicine, Szeged, Hungary
| | - Istvan Toth
- Departments of Physiology and Biochemistry, University of Veterinary Medicine, Budapest 1078, Hungary
| | - Tamas L Horvath
- Department of Animal Physiology and Animal Health, Faculty of Agricultural and Environmental Sciences, Szent István University, Páter Károly u. 1, H-2100 Gödöllő, Hungary; Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT, USA; Departments of Anatomy and Histology, University of Veterinary Medicine, Budapest 1078, Hungary.
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7
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Cambiasso MJ, Cisternas CD, Ruiz-Palmero I, Scerbo MJ, Arevalo MA, Azcoitia I, Garcia-Segura LM. Interaction of sex chromosome complement, gonadal hormones and neuronal steroid synthesis on the sexual differentiation of mammalian neurons. J Neurogenet 2017; 31:300-306. [DOI: 10.1080/01677063.2017.1390572] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Maria Julia Cambiasso
- Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC-CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
- Departamento de Biología Bucal, Facultad de Odontología, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Carla Daniela Cisternas
- Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC-CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
- Departamento de Biología Bucal, Facultad de Odontología, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Isabel Ruiz-Palmero
- CSIC, Instituto Cajal, Madrid, Spain
- Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain
| | - Maria Julia Scerbo
- Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC-CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
- Departamento de Biología Bucal, Facultad de Odontología, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Maria Angeles Arevalo
- CSIC, Instituto Cajal, Madrid, Spain
- Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain
| | - Iñigo Azcoitia
- Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain
- Department of Cell Biology, Faculty of Biology, Universidad Complutense, Ciudad Universitaria, Madrid, Spain
| | - Luis M. Garcia-Segura
- CSIC, Instituto Cajal, Madrid, Spain
- Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain
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8
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Xiao H, Deng M, Yang B, Tang J, Hu Z. Role of glycogen synthase kinase 3 in ischemia-induced blood-brain barrier disruption in aged female rats. J Neurochem 2017; 142:194-203. [PMID: 28440874 DOI: 10.1111/jnc.14051] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 03/20/2017] [Accepted: 04/06/2017] [Indexed: 12/19/2022]
Abstract
Estrogen receptors have protective effects against ischemic brain injury. However, the molecular mechanisms underlying this phenomenon have yet to be well studied. Given that inhibition of glycogen synthase kinase (GSK3) can reduce cerebral ischemia/reperfusion injury, we hypothesized that estrogen receptors-mediated protective effects against ischemia-induced blood-brain barrier (BBB) disruption involve inhibition of GSK3. Thus, we evaluated GSK3 expression in the brain of ovariectomized female rats, and examined the effects of intracerebroventricular pre-treatments of SB216763, GSK3 inhibitor, on BBB permeability following middle cerebral artery occlusion (MCAO). We also examined the role of specific estrogen receptor subtype in regulation of GSK3 expression and BBB permeability after MCAO. We found that ovariectomized female rats exhibited increased mRNA levels of estrogen receptor α (ERα) and estrogen receptor β (ERβ), and increased protein levels of GSK3β but not GSK3α in brain cortical areas. Furthermore, intracerebroventricular pre-treatments of SB216763 dose-dependently attenuated brain infarction volume, brain water contents, neurological deficits, and BBB disruption, and increased tight junction protein ZO-1 and occludin expression at 24 h following MCAO. Finally, activation of ERβ but not ERα dose-dependently decreased GSK3β expression at 24 h following MCAO. This was associated with increased tight junction protein expression and improved neurological scores. Thus, our study suggested that activation of ERβ may protect against brain ischemia-induced BBB disruption by inhibiting GSK3β-mediated signaling.
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Affiliation(s)
- Han Xiao
- Department of Neurology, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Mingyang Deng
- Department of Hematology, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Binbin Yang
- Department of Neurology, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Jianguang Tang
- Department of Neurology, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Zhiping Hu
- Department of Neurology, The Second Xiangya Hospital, Central South University, Changsha, China
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9
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Daftary SS, Gore AC. IGF-1 in the Brain as a Regulator of Reproductive Neuroendocrine Function. Exp Biol Med (Maywood) 2016; 230:292-306. [PMID: 15855296 DOI: 10.1177/153537020523000503] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Given the close relationship among neuroendocrine systems, it Is likely that there may be common signals that coordinate the acquisition of adult reproductive function with other homeo-static processes. In this review, we focus on central nervous system insulin-like growth factor-1 (IGF-1) as a signal controlling reproductive function, with possible links to somatic growth, particularly during puberty. In vertebrates, the appropriate neurosecretion of the decapeptide gonadotropin-releas-ing hormone (GnRH) plays a critical role in the progression of puberty. Gonadotropin-releasing hormone is released in pulses from neuroterminals in the median eminence (ME), and each GnRH pulse triggers the production of the gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH). These pituitary hormones in turn stimulate the synthesis and release of sex steroids by the gonads. Any factor that affects GnRH or gonadotropin pulsatility is important for puberty and reproductive function and, among these factors, the neurotrophic factor IGF-1 is a strong candidate. Although IGF-1 is most commonly studied as the tertiary peripheral hormone in the somatotropic axis via its synthesis in the liver, IGF-1 Is also synthesIzed in the brain, within neurons and glia. In neuroendocrine brain regions, central IGF-1 plays roles in the regulation of neuroendocrine functions, including direct actions on GnRH neurons. Moreover, GnRH neurons themselves co-express IGF-1 and the IGF-1 receptor, and this expression is developmentally regulated. Here, we examine the role of IGF-1 acting in the hypothalamus as a critical link between reproductive and other neuroendocrine functions.
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Affiliation(s)
- Shabrine S Daftary
- Department of Pharmacology and Biological Chemistry, Mount Sinai School of Medicine, New York, NY 10029, USA
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10
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Galván-Ramírez MDLL, Gutiérrez-Maldonado AF, Verduzco-Grijalva F, Jiménez JMD. The role of hormones on Toxoplasma gondii infection: a systematic review. Front Microbiol 2014; 5:503. [PMID: 25346725 PMCID: PMC4191157 DOI: 10.3389/fmicb.2014.00503] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 09/08/2014] [Indexed: 11/16/2022] Open
Abstract
Background:Toxoplasma gondii is the causal agent of toxoplasmosis in which one third of the world's population has been infected. In pregnant women, it may cause abortion and severe damage to the fetal central nervous system. During pregnancy, the prevalence of toxoplasmosis increases throughout the second and third quarter of gestation, simultaneously progesterone and 17β-estradiol also increase. Thus, it has been suggested that these hormones can aggravate or reduce parasite reproduction. The aim of this study was reviewing the relationship between hormones and infection caused by T. gondii in several experimental animal models and humans, focused mainly on: (a) congenital transmission, (b) parasite reproduction, (c) strain virulence, (d) levels of hormone in host induced by T. gondii infection, and (e) participation of hormone receptors in T. gondii infection. Are the hormones specific modulators of T. gondii infection? A systematic review methodology was used to consult several databases (Pub Med, Lilacs, Medline, Science direct, Scielo, Ebsco, Sprinker, Wiley, and Google Scholar) dated from September, 2013 to March, 2014. Results: Thirty studies were included; eight studies in humans and 22 in animals and cell cultures. In the human studies, the most studied hormones were testosterone, progesterone, prolactin, and 17β-estradiol. Type I (RH and BK) and Type II (Prugniaud, SC, ME49, T45, P78, and T38) were the most frequent experimental strains. Conclusions: Thirty-five years have passed since the first studies regarding T. gondii infection and its relationship with hormones. This systematic review suggests that hormones modulate T. gondii infection in different animal models. However, given that data were not comparable, further studies are required to determine the mechanism of hormone action in the T. gondii infectious process.
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Affiliation(s)
- María de la Luz Galván-Ramírez
- Neurophysiology Laboratory, Department of Physiology, Health Sciences University Center, University of Guadalajara Guadalajara, Jalisco, Mexico
| | - Adrián Fernando Gutiérrez-Maldonado
- Neurophysiology Laboratory, Department of Physiology, Health Sciences University Center, University of Guadalajara Guadalajara, Jalisco, Mexico
| | - Fabiola Verduzco-Grijalva
- Neurophysiology Laboratory, Department of Physiology, Health Sciences University Center, University of Guadalajara Guadalajara, Jalisco, Mexico
| | - Judith Marcela Dueñas Jiménez
- Neurophysiology Laboratory, Department of Physiology, Health Sciences University Center, University of Guadalajara Guadalajara, Jalisco, Mexico
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11
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Antagonism of brain insulin-like growth factor-1 receptors blocks estradiol effects on memory and levels of hippocampal synaptic proteins in ovariectomized rats. Psychopharmacology (Berl) 2014; 231:899-907. [PMID: 24146138 PMCID: PMC3945205 DOI: 10.1007/s00213-013-3310-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 09/27/2013] [Indexed: 01/01/2023]
Abstract
RATIONALE Treatment with estradiol, the primary estrogen produced by the ovaries, enhances hippocampus-dependent spatial memory and increases levels of hippocampal synaptic proteins in ovariectomized rats. Increasing evidence indicates that the ability of estradiol to impact the brain and behavior is dependent upon its interaction with insulin-like growth factor-1 (IGF-1). OBJECTIVE The goal of the current experiment was to test the hypothesis that the ability of estradiol to impact hippocampus-dependent memory and levels of hippocampal synaptic proteins is dependent on its interaction with IGF-1. METHODS Adult rats were ovariectomized and implanted with estradiol or control capsules and trained on a radial-maze spatial memory task. After training, rats were implanted with intracerebroventricular cannulae attached to osmotic minipumps (flow rate 0.15 μl/h). Half of each hormone treatment group received continuous delivery of JB1 (300 μg/ml), an IGF-1 receptor antagonist, and half received delivery of aCSF vehicle. Rats were tested on trials in the radial-arm maze during which delays were imposed between the fourth and fifth arm choices. Hippocampal levels of synaptic proteins were measured by western blotting. RESULTS Estradiol treatment resulted in significantly enhanced memory. JB1 blocked that enhancement. Estradiol treatment resulted in significantly increased hippocampal levels of postsynaptic density protein 95 (PSD-95), spinophilin, and synaptophysin. JB1 blocked the estradiol-induced increase of PSD-95 and spinophilin and attenuated the increase of synaptophysin. CONCLUSIONS Results support a role for IGF-1 receptor activity in estradiol-induced enhancement of spatial memory that may be dependent on changes in synapse structure in the hippocampus brought upon by estradiol/IGF-1 interactions.
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Park S, Nozaki K, Smith JA, Krause JS, Banik NL. Cross-talk between IGF-1 and estrogen receptors attenuates intracellular changes in ventral spinal cord 4.1 motoneuron cells because of interferon-gamma exposure. J Neurochem 2013; 128:904-18. [PMID: 24188094 DOI: 10.1111/jnc.12520] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 10/16/2013] [Accepted: 10/21/2013] [Indexed: 12/26/2022]
Abstract
Insulin-like growth factor-1 (IGF-1) is a neuroprotective growth factor that promotes neuronal survival by inhibition of apoptosis. To examine whether IGF-1 exerts cytoprotective effects against extracellular inflammatory stimulation, ventral spinal cord 4.1 (VSC4.1) motoneuron cells were treated with interferon-gamma (IFN-γ). Our data demonstrated apoptotic changes, increased calpain:calpastatin and Bax:Bcl-2 ratios, and expression of apoptosis-related proteases (caspase-3 and -12) in motoneurons rendered by IFN-γ in a dose-dependent manner. Post-treatment with IGF-1 attenuated these changes. In addition, IGF-1 treatment of motoneurons exposed to IFN-γ decreased expression of inflammatory markers (cyclooxygenase-2 and nuclear factor-kappa B:inhibitor of kappa B ratio). Furthermore, IGF-1 attenuated the loss of expression of IGF-1 receptors (IGF-1Rα and IGF-1Rβ) and estrogen receptors (ERα and ERβ) induced by IFN-γ. To determine whether the protective effects of IGF-1 are associated with ERs, ERs antagonist ICI and selective siRNA targeted against ERα and ERβ were used in VSC4.1 motoneurons. Distinctive morphological changes were observed following siRNA knockdown of ERα and ERβ. In particular, apoptotic cell death assessed by TUNEL assay was enhanced in both ERα and ERβ-silenced VSC4.1 motoneurons following IFN-γ and IGF-1 exposure. These results suggest that IGF-1 protects motoneurons from inflammatory insult by a mechanism involving pivotal interactions with ERα and ERβ.
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Affiliation(s)
- Sookyoung Park
- Department of Neurosciences, Division of Neurology, College of Health Professions, Medical University of South Carolina, Charleston, South Carolina, USA
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13
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Pérez C, Navarro A, Martínez E, Ordóñez C, Del Valle E, Tolivia J. Age-related changes of apolipoprotein D expression in female rat central nervous system with chronic estradiol treatment. AGE (DORDRECHT, NETHERLANDS) 2012; 34:895-904. [PMID: 21761133 PMCID: PMC3682073 DOI: 10.1007/s11357-011-9286-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Accepted: 06/21/2011] [Indexed: 05/31/2023]
Abstract
Aging is associated with a reduction in metabolic functions, increased incidence of neurodegenerative diseases, and memory or cognitive dysfunction. With aging, a decrease in plasma estrogen levels, related to loss of gonadal function, occurs in females. Estrogens have neuroprotective effects and estradiol treatment improves some aspects of neuronal homeostasis affected by aging. In other way, recent studies show that apo D can play a neuroprotective role in some neuropathologies and during aging. The possible relation between estradiol treatment and the expression of apo D, during aging in the CNS, was investigated in female rats. Our results confirm an expression of apo D zone-dependent, in relation with aging, and an overexpression of apo D related to ovariectomy and estradiol treatment. This overexpression strengthens the idea that apo D plays a neuroprotective role in the CNS.
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Affiliation(s)
- Cristina Pérez
- Department of Morphology and Cellular Biology, 8ª Planta Facultad de Medicina, University of Oviedo, c/ Julián Clavería s/n, Oviedo, 33006 Spain
| | - Ana Navarro
- Department of Morphology and Cellular Biology, 8ª Planta Facultad de Medicina, University of Oviedo, c/ Julián Clavería s/n, Oviedo, 33006 Spain
| | - Eva Martínez
- Department of Morphology and Cellular Biology, 8ª Planta Facultad de Medicina, University of Oviedo, c/ Julián Clavería s/n, Oviedo, 33006 Spain
| | - Cristina Ordóñez
- Department of Morphology and Cellular Biology, 8ª Planta Facultad de Medicina, University of Oviedo, c/ Julián Clavería s/n, Oviedo, 33006 Spain
| | - Eva Del Valle
- Department of Morphology and Cellular Biology, 8ª Planta Facultad de Medicina, University of Oviedo, c/ Julián Clavería s/n, Oviedo, 33006 Spain
| | - Jorge Tolivia
- Department of Morphology and Cellular Biology, 8ª Planta Facultad de Medicina, University of Oviedo, c/ Julián Clavería s/n, Oviedo, 33006 Spain
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Arevalo MA, Ruiz-Palmero I, Scerbo MJ, Acaz-Fonseca E, Cambiasso MJ, Garcia-Segura LM. Molecular mechanisms involved in the regulation of neuritogenesis by estradiol: Recent advances. J Steroid Biochem Mol Biol 2012; 131:52-6. [PMID: 21971420 DOI: 10.1016/j.jsbmb.2011.09.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Revised: 09/19/2011] [Accepted: 09/21/2011] [Indexed: 12/13/2022]
Abstract
This review analyzes the signaling mechanisms activated by estradiol to regulate neuritogenesis in several neuronal populations. Estradiol regulates axogenesis by the activation of the mitogen activated protein kinase (MAPK) cascade through estrogen receptor α located in the plasma membrane. In addition, estradiol regulates MAPK signaling via the activation of protein kinase C and by increasing the expression of brain derived neurotrophic factor and tyrosine kinase receptor B. Estradiol also interacts with the signaling of insulin-like growth factor-I receptor through estrogen receptor α, modulating the phosphoinositide-3 kinase signaling pathway, which contributes to the stabilization of microtubules. Finally, estradiol modulates dendritogenesis by the inhibition of Notch signaling, by a mechanism that, at least in hippocampal neurons, is mediated by G-protein coupled receptor 30. This article is part of a Special Issue entitled 'Neurosteroids'.
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15
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Scalise T, Győrffy A, Tóth I, Kiss D, Somogyi V, Goszleth G, Bartha T, Frenyó L, Zsarnovszky A. Ligand-induced changes in Oestrogen and thyroid hormone receptor expression in the developing rat cerebellum: A comparative quantitative PCR and Western blot study. Acta Vet Hung 2012; 60:263-84. [PMID: 22609997 DOI: 10.1556/avet.2012.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Oestrogen (E2) and thyroid hormones (THs) are key regulators of cerebellar development. Recent reports implicate a complex mechanism through which E2 and THs influence the expression levels of each other's receptors (ERs and TRs) to precisely mediate developmental signals and modulate signal strength. We examined the modulating effects of E2 and THs on the expression levels of their receptor mRNAs and proteins in cultured cerebellar cells obtained from 7-day-old rat pups. Cerebellar granule cell cultures were treated with either E2, THs or a combination of these hormones, and resulting receptor expression levels were determined by quantitative PCR and Western blot techniques. The results were compared to non-treated controls and to samples obtained from 14-day-old in situ cerebella. Additionally, we determined the glial effects on the regulation of ER-TR expression levels. The results show that (i) ER and TR expression depends on the combined presence of E2 and THs; (ii) glial cells mediate the hormonal regulation of neuronal ER-TR expression and (iii) loss of tissue integrity results in characteristic changes in ER-TR expression levels. These observations suggest that both E2 and THs, in adequate amounts, are required for the precise orchestration of cerebellar development and that alterations in the ratio of E2/THs may influence signalling mechanisms involved in neurodevelopment. Comparison of data from in vitro and in situ samples revealed a shift in receptor expression levels after loss of tissue integrity, suggesting that such adjusting/regenerative mechanisms may function after cerebellar tissue injury as well.
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Affiliation(s)
- Trudy Scalise
- 1 Szent István University Department of Physiology and Biochemistry, Faculty of Veterinary Sciences István u. 2 H-1078 Budapest Hungary
| | - Andrea Győrffy
- 1 Szent István University Department of Physiology and Biochemistry, Faculty of Veterinary Sciences István u. 2 H-1078 Budapest Hungary
| | - István Tóth
- 1 Szent István University Department of Physiology and Biochemistry, Faculty of Veterinary Sciences István u. 2 H-1078 Budapest Hungary
| | - Dávid Kiss
- 1 Szent István University Department of Physiology and Biochemistry, Faculty of Veterinary Sciences István u. 2 H-1078 Budapest Hungary
| | - Virág Somogyi
- 1 Szent István University Department of Physiology and Biochemistry, Faculty of Veterinary Sciences István u. 2 H-1078 Budapest Hungary
| | - Gréta Goszleth
- 1 Szent István University Department of Physiology and Biochemistry, Faculty of Veterinary Sciences István u. 2 H-1078 Budapest Hungary
| | - Tibor Bartha
- 1 Szent István University Department of Physiology and Biochemistry, Faculty of Veterinary Sciences István u. 2 H-1078 Budapest Hungary
| | - László Frenyó
- 1 Szent István University Department of Physiology and Biochemistry, Faculty of Veterinary Sciences István u. 2 H-1078 Budapest Hungary
| | - Attila Zsarnovszky
- 1 Szent István University Department of Physiology and Biochemistry, Faculty of Veterinary Sciences István u. 2 H-1078 Budapest Hungary
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Pillon D, Cadiou V, Angulo L, Duittoz AH. Maternal exposure to 17-alpha-ethinylestradiol alters embryonic development of GnRH-1 neurons in mouse. Brain Res 2012; 1433:29-37. [DOI: 10.1016/j.brainres.2011.11.030] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2011] [Revised: 11/07/2011] [Accepted: 11/11/2011] [Indexed: 11/16/2022]
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17
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Desai M, Li T, Ross MG. Fetal hypothalamic neuroprogenitor cell culture: preferential differentiation paths induced by leptin and insulin. Endocrinology 2011; 152:3192-201. [PMID: 21652728 PMCID: PMC3138224 DOI: 10.1210/en.2010-1217] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In response to temporally orchestrated growth factor stimulation, developing neural stem/progenitor cells undergo extensive self-renewal and then generate neurons and astrocytes. Fetal neonatal leptin and insulin deficiency results in reduced hypothalamic axonal pathways regulating appetite, which may predispose to offspring hyperphagia and obesity. Neural development of the arcuate nucleus, a key target of adiposity signals, leptin and insulin, is immature at birth. Hence, to explore proximate effects of leptin/insulin on hypothalamic development, we determined trophic and differentiation effects on neural stem/progenitor cells using a model of fetal hypothalamic neurospheres (NS). NS cultures were produced from embryonic d 20 fetal rats and passage 1 and passage 2 cells examined for proliferation and differentiation into neurons (neuronal nuclei, class IIIβ-tubulin, and doublecortin) and astrocytes (glial fibrillary acidic protein). Leptin-induced NS proliferation was significantly greater than that induced by insulin, although both effects were blocked by Notch, extracellular signal-regulated kinase, or signal transducer and activator of transcription 3 inhibition. Leptin preferentially induced neuronal, whereas insulin promoted astrocyte differentiation. Extracellular signal-regulated kinase inhibition suppressed both leptin and insulin-mediated differentiation, whereas signal transducer and activator of transcription inhibition only affected leptin-mediated responses. These findings demonstrate preferential and disparate differentiation paths induced by leptin and insulin. Altered fetal exposure to leptin or insulin, resulting from fetal growth restriction, macrosomia, or maternal diabetes, may potentially have marked effects on fetal brain development.
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Affiliation(s)
- Mina Desai
- Perinatal Research Laboratories, Department of Obstetrics and Gynecology, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California 90095, USA.
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Short- and long-term treatment with estradiol or progesterone modifies the expression of GFAP, MAP2 and Tau in prefrontal cortex and hippocampus. Life Sci 2011; 89:123-8. [PMID: 21683086 DOI: 10.1016/j.lfs.2011.05.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Revised: 03/16/2011] [Accepted: 05/25/2011] [Indexed: 11/21/2022]
Abstract
AIMS We analyzed the effects of the short- and long-term administration of estradiol (E2) or progesterone (P4) after ovariectomy on the expression of MAP2, Tau and GFAP in prefrontal cortex and hippocampus. MAIN METHODS Sprague Dawley rats were ovariectomized and immediately treated with E2 or P4 for 2 or 18 weeks. At the end of treatments, hippocampus and prefrontal cortex were excised, proteins were extracted and MAP2, Tau and GFAP were analyzed by Western blot. KEY FINDINGS MAP2 and Tau content was not modified by E2 in the prefrontal cortex. On the contrary, P4 decreased MAP2 content after a short-term treatment, while it increased that of MAP2 and TAU in this brain region after a long-term treatment. E2 increased MAP2 content in hippocampus. In this region, short-term administration of P4 increased that of MAP2. GFAP content was diminished after a long-term administration of P4 in hippocampus. SIGNIFICANCE Current data emphasize the importance of short- and long-term sex steroid treatment on neuronal and glial cytoskeletal proteins expression.
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Ruiz-Palmero I, Simon-Areces J, Garcia-Segura LM, Arevalo MA. Notch/neurogenin 3 signalling is involved in the neuritogenic actions of oestradiol in developing hippocampal neurones. J Neuroendocrinol 2011; 23:355-64. [PMID: 21251092 DOI: 10.1111/j.1365-2826.2011.02110.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The ovarian hormone oestradiol promotes neuritic outgrowth in different neuronal types, by mechanisms that remain elusive. Recent studies have shown that the Notch-regulated transcription factor neurogenin 3 controls neuritogenesis. In the present study, we assessed whether oestradiol regulates neurogenin 3 in primary hippocampal neurones. As expected, neuritogenesis was increased in the cultures treated with oestradiol. However, the neuritogenic action of oestradiol was not prevented by ICI 182,780, an antagonist of classical oestrogen receptors (ERs). Oestradiol decreased the expression of Hairy and Enhancer of Split-1, a Notch-regulated gene that negatively controls the expression on neurogenin 3. Furthermore, oestradiol increased the expression of neurogenin 3 and regulated its distribution between the neuronal cell nucleus and the cytoplasm. The effect of oestradiol on neurogenin 3 expression was not blocked by antagonists of classical nuclear ER-mediated transcription and was not imitated by selective agonists of nuclear ERs. By contrast, G1, a ligand of G protein receptor 30/G protein-coupled ER, fully reproduced the effect of oestradiol on neuritogenesis, neurogenin 3 expression and neurogenin 3 subcellular localisation. Moreover, knockdown of neurogenin 3 in neurones by transfection with small interference RNA for neurogenin 3 completely abrogated the neuritogenic actions of oestradiol and G1. These results suggest that oestradiol regulates neurogenin 3 in primary hippocampal neurones by a nonclassical steroid signalling mechanism, which involves the down-regulation of Notch activity and the activation of G protein receptor 30/G protein-coupled ER or of other unknown G1 targets. In addition, our findings indicate that neurogenin 3 participates in the neuritogenic mechanisms of oestradiol in hippocampal neurones.
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Hiney JK, Srivastava VK, Dees WL. Manganese induces IGF-1 and cyclooxygenase-2 gene expressions in the basal hypothalamus during prepubertal female development. Toxicol Sci 2011; 121:389-96. [PMID: 21402727 DOI: 10.1093/toxsci/kfr057] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Precocious puberty is a significant child health problem, especially in girls, because 95% of cases are idiopathic. Our earlier studies demonstrated that low-dose levels of manganese (Mn) caused precocious puberty via stimulating the secretion of luteinizing hormone-releasing hormone (LHRH). Because glial-neuronal communications are important for the activation of LHRH secretion at puberty, we investigated the effects of prepubertal Mn exposure on specific glial-derived puberty-related genes known to affect neuronal LHRH release. Animals were supplemented with MnCl(2) (10 mg/kg) or saline by gastric gavage from day 12 until day 22 or day 29, then decapitated, and brains removed. The site of LHRH release is the medial basal hypothalamus (MBH), and tissues from this area were analyzed by real-time PCR for transforming growth factor α (TGFα), insulin-like growth factor-1 (IGF-1), and cyclooxygenase-2 (COX-2) messenger RNA levels. Protein levels for IGF-1 receptor (IGF-1R) were measured by Western blot analysis. LHRH gene expression was measured in the preoptic area/anteroventral periventricular (POA/AVPV) region. In the MBH, at 22 days, IGF-1 gene expression was increased (p < 0.05) with a concomitant increase (p < 0.05) in IGF-1R protein expression. Mn also increased (p < 0.01) COX-2 gene expression. At 29 days, the upregulation of IGF-1 (p < 0.05) and COX-2 (p < 0.05) continued in the MBH. At this time, we observed increased (p < 0.05) LHRH gene expression in the POA/AVPV. Additionally, Mn stimulated prostaglandin E(2) and LHRH release from 29-day-old median eminences incubated in vitro. These results demonstrate that Mn, through the upregulation of IGF-1 and COX-2, may promote maturational events and glial-neuronal communications facilitating the increased neurosecretory activity, including that of LHRH, resulting in precocious pubertal development.
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Affiliation(s)
- Jill K Hiney
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine, Texas A&M University, College Station, Texas 77843-4458, USA
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21
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Arevalo MA, Ruiz-Palmero I, Simon-Areces J, Acaz-Fonseca E, Azcoitia I, Garcia-Segura LM. Estradiol meets notch signaling in developing neurons. Front Endocrinol (Lausanne) 2011; 2:21. [PMID: 22654797 PMCID: PMC3356013 DOI: 10.3389/fendo.2011.00021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Accepted: 07/31/2011] [Indexed: 01/04/2023] Open
Abstract
The transmembrane receptor Notch, a master developmental regulator, controls gliogenesis, neurogenesis, and neurite development in the nervous system. Estradiol, acting as a hormonal signal or as a neurosteroid, also regulates these developmental processes. Here we review recent evidence indicating that estradiol and Notch signaling interact in developing hippocampal neurons by a mechanism involving the putative membrane receptor G protein-coupled receptor 30. This interaction is relevant for the control of neuronal differentiation, since the downregulation of Notch signaling by estradiol results in the upregulation of neurogenin 3, which in turn promotes dendritogenesis.
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Affiliation(s)
| | - Isabel Ruiz-Palmero
- Instituto Cajal, Consejo Superior de Investigaciones CientíficasMadrid, Spain
| | - Julia Simon-Areces
- Instituto Cajal, Consejo Superior de Investigaciones CientíficasMadrid, Spain
| | | | - Iñigo Azcoitia
- Facultad de Biología, Biología Celular, Universidad Complutense de MadridMadrid, Spain
| | - Luis Miguel Garcia-Segura
- Instituto Cajal, Consejo Superior de Investigaciones CientíficasMadrid, Spain
- *Correspondence: Luis Miguel Garcia-Segura, Instituto Cajal, Consejo Superior de Investigaciones Científicas, Avenida Doctor Arce 37, E-28002 Madrid, Spain. e-mail:
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Interactions of estradiol and insulin-like growth factor-I signalling in the nervous system: new advances. PROGRESS IN BRAIN RESEARCH 2010; 181:251-72. [PMID: 20478442 DOI: 10.1016/s0079-6123(08)81014-x] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Estradiol and insulin-like growth factor-I (IGF-I) interact in the brain to regulate a variety of developmental and neuroplastic events. Some of these interactions are involved in the control of hormonal homeostasis and reproduction. However, the interactions may also potentially impact on affection and cognition by the regulation of adult neurogenesis in the hippocampus and by promoting neuroprotection under neurodegenerative conditions. Recent studies suggest that the interaction of estradiol and IGF-I is also relevant for the control of cholesterol homeostasis in neural cells. The molecular mechanisms involved in the interaction of estradiol and IGF-I include the cross-regulation of the expression of estrogen and IGF-I receptors, the regulation of estrogen receptor-mediated transcription by IGF-I and the regulation of IGF-I receptor signalling by estradiol. Current investigations are evidencing the role exerted by key signalling molecules, such as glycogen synthase kinase 3 and beta-catenin, in the cross-talk of estrogen receptors and IGF-I receptors in neural cells.
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Xu L, Chen WF, Wong MS. Ginsenoside Rg1 protects dopaminergic neurons in a rat model of Parkinson's disease through the IGF-I receptor signalling pathway. Br J Pharmacol 2009; 158:738-48. [PMID: 19703168 DOI: 10.1111/j.1476-5381.2009.00361.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND AND PURPOSE We have shown that ginsenoside Rg1 is a novel class of potent phytoestrogen and activates insulin-like growth factor-I receptor (IGF-IR) signalling pathway in human breast cancer MCF-7 cells. The present study tested the hypothesis that the neuroprotective actions of Rg1 involved activation of the IGF-IR signalling pathway in a rat model of Parkinson's disease, induced by 6-hydroxydopamine (6-OHDA). EXPERIMENTAL APPROACH Ovariectomized rats were infused unilaterally with 6-OHDA into the medial forebrain bundle to lesion the nigrostriatal dopamine pathway and treated with Rg1 (1.5 h after 6-OHDA injections) in the absence or presence of the IGF-IR antagonist JB-1 (1 h before Rg1 injections). The rotational behaviour induced by apomorphine and the dopamine content in the striatum were studied. Protein and gene expression of tyrosine hydroxylase, dopamine transporter and Bcl-2 in the substantia nigra were also determined. KEY RESULTS Rg1 treatment ameliorated the rotational behaviour induced by apomorphine in our model of nigrostriatal injury. This effect was partly blocked by JB-1. 6-OHDA significantly decreased the dopamine content of the striatum and treatment with Rg1 reversed this decrease. Treatment with Rg1 of 6-OHDA-lesioned rats reduced neurotoxicity, as measured by tyrosine hydroxylase, dopamine transporter and Bcl-2 protein and gene level in the substantia nigra. These effects were abolished by JB-1. CONCLUSIONS AND IMPLICATIONS These data provide the first evidence that Rg1 has neuroprotective effects on dopaminergic neurons in the 6-OHDA model of nigrostriatal injury and its actions might involve activation of the IGF-IR signalling pathway.
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Affiliation(s)
- Li Xu
- Department of Physiology, Medical College of Qingdao University, Qingdao, China
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Marin R, Díaz M, Alonso R, Sanz A, Arévalo MA, Garcia-Segura LM. Role of estrogen receptor alpha in membrane-initiated signaling in neural cells: interaction with IGF-1 receptor. J Steroid Biochem Mol Biol 2009; 114:2-7. [PMID: 19167493 DOI: 10.1016/j.jsbmb.2008.12.014] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2008] [Accepted: 12/31/2008] [Indexed: 12/25/2022]
Abstract
The mechanisms of action of estradiol in the nervous system involve nuclear-initiated steroid signaling and membrane-initiated steroid signaling. Estrogen receptors (ERs) are involved in both mechanisms. ERalpha interacts with the signaling of IGF-1 receptor in neural cells: ERalpha transcriptional activity is regulated by IGF-1 receptor signaling and estradiol regulates IGF-1 receptor signaling. The interaction between ERalpha and the IGF-1 receptor in the brain may occur at the plasma membrane of neurons and glial cells. Caveolin-1 may provide the scaffolding for the interaction of different membrane-associated molecules, including voltage-dependent anion channel, ERalpha and IGF-I receptor.
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Affiliation(s)
- Raquel Marin
- Laboratory of Cellular Neurobiology, Department of Physiology & Institute of Biomedical Technologies, University of La Laguna, School of Medicine, Santa Cruz de Tenerife, Spain
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Hiney JK, Srivastava VK, Pine MD, Les Dees W. Insulin-like growth factor-I activates KiSS-1 gene expression in the brain of the prepubertal female rat. Endocrinology 2009; 150:376-84. [PMID: 18703622 PMCID: PMC2630893 DOI: 10.1210/en.2008-0954] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Accepted: 08/05/2008] [Indexed: 11/19/2022]
Abstract
KiSS-1 gene expression has been shown to increase as puberty approaches, and its peptide products, kisspeptins, are involved in LHRH secretion at puberty. Factors contributing to increased KiSS-1 expression, however, have not been identified; thus, the purpose of this study was to assess whether IGF-I could induce transcription of this gene in prepubertal female rats. IGF-I or saline was centrally administered to immature rats that were killed 2, 4, and 6 h later. Real-time PCR revealed that IGF-I induced (P < 0.01) KiSS-1 gene expression at 6 h in a tissue fragment that contained both the anteroventral periventricular (AVPV) and arcuate (ARC) nuclei. Subsequently, the AVPV and ARC nuclei were separated to assess whether region-specific effects could be identified. IGF-I stimulated (P < 0.01) KiSS-1 gene expression in the AVPV nucleus at 6 h after injection, with no change observed in the ARC nucleus. Serum estradiol (E2) levels were not altered at any time point after IGF-I, demonstrating that the increased KiSS-1 expression observed was not caused by an elevation in E2. Additionally, the IGF-I action to induce KiSS-1 gene expression in the AVPV nucleus was further demonstrated when the IGF-I was administered systemically. E2 appears to play an important permissive role because 1-d ovariectomized rats responded to IGF-I with increased (P < 0.01) KiSS-1 expression, whereas, 20 d after ovariectomy, when the E2 levels had fallen below assay sensitivity, the IGF-I was unable to induce KiSS-1 expression. The IGF-I effect was further demonstrated by showing that the IGF-I receptor antagonist, JB-1, blocked the IGF-I-induced increase in KiSS-1 expression. Collectively, these data indicate that IGF-I is an activator of the KiSS-1 gene in the prepubertal female rat.
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Affiliation(s)
- Jill K Hiney
- Department of Integrative Biosciences, College of Veterinary Medicine, Texas A&M University, College Station, Texas 77843-4458, USA
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Agça E, Batailler M, Tillet Y, Chemineau P, Duittoz AH. Modulation of estrogen receptors during development inhibits neurogenesis of precursors to GnRH-1 neurones: in vitro studies with explants of ovine olfactory placode. Brain Res 2008; 1223:34-41. [PMID: 18597744 DOI: 10.1016/j.brainres.2008.05.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2008] [Revised: 05/05/2008] [Accepted: 05/13/2008] [Indexed: 11/29/2022]
Abstract
The aim of the present study was to explore the putative effects of agonists and antagonists of the estradiol receptor on the early phase of GnRH-1 neuron development. To address this question we used an in vitro model of GnRH-1 neurons using cultured olfactory placode from sheep embryos on day 26 of gestation. Previous studies on this model have shown that in vitro the development of GnRH-1 neurons mimics in vivo development up to the start of pulsatile GnRH-1 secretion, To address the effects of modulating the estrogen receptor, cultures were treated with the endogenous and synthetic ligands of estradiol receptors: 17beta-estradiol, 17alpha-estradiol and tamoxifen. Neurogenesis was measured by incorporation of [(3)H]-thymidine. Morphometric parameters were evaluated by image analysis. The main results are that antagonism of estradiol receptors induced an important decrease in neurogenesis but had little effect on morphometric parameters, suggesting that during this early phase of development, maternal estrogens are important to achieve correct development of the GnRH-1 neuronal network.
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Affiliation(s)
- Esma Agça
- Université de Tours, Physiologie de la Reproduction et des Comportements, IFR135, UMR 6175 INRA, CNRS, Haras Nationaux, Nouzilly, France
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Cosma M, Bailey J, Miles JM, Bowers CY, Veldhuis JD. Pituitary and/or peripheral estrogen-receptor alpha regulates follicle-stimulating hormone secretion, whereas central estrogenic pathways direct growth hormone and prolactin secretion in postmenopausal women. J Clin Endocrinol Metab 2008; 93:951-8. [PMID: 18089703 PMCID: PMC2266945 DOI: 10.1210/jc.2007-1322] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Estradiol (E(2)) stimulates GH and prolactin secretion and suppresses FSH secretion in postmenopausal women. Whether central nervous system (CNS) or pituitary mechanisms (or both) mediate such actions is not known. OBJECTIVE Our objective was to distinguish between hypothalamic and pituitary or peripheral (hepatic) actions of E2. SETTING This study was performed in an academic medical center. DESIGN This was a double-blind, prospectively randomized, placebo (Pl)-controlled study. METHODS The capability of a selective, noncompetitive, non-CNS permeant estrogen receptor (ER)-alpha antagonist, fulvestrant (FUL) to antagonize the effects of transdermal E2 and Pl on GH, prolactin, and FSH secretion was assessed in 43 women (ages 50-80 yr) in a four parallel-cohort study. Each woman received four secretagogue infusions to stimulate GH secretion. IGF-I and its binding proteins were measured secondarily. RESULTS Administration of Pl/E2 increased GH and prolactin concentrations by 100%, and suppressed FSH concentrations by more than 50% (each P<or=0.004 compared with Pl/Pl). Treatment with FUL/E2 compared with Pl/E2 partially relieved estrogen's inhibition of FSH secretion (P=0.041), without altering E2's stimulation of prolactin secretion. ANOVA further revealed that: 1) estrogen milieu (P=0.014) and secretagogue type (P<0.001) each determined GH concentrations; 2) FUL/Pl suppressed IGF-I concentrations (P<0.001); 3) FUL abrogated estrogen's elevation of IGF binding protein-1 concentrations (P<0.001); and 4) FUL did not oppose estrogen's suppression of IGF binding protein-3 concentrations (P<0.001). SUMMARY AND CONCLUSIONS Responses to a non-CNS permeant ERalpha antagonist indicate that E2 inhibits FSH secretion in part via pituitary/peripheral ERalpha, drives prolactin output via nonpituitary/nonperipheral-ERalpha effects, and directs GH secretion and IGF-I-binding proteins by complex mechanisms.
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Affiliation(s)
- Mihaela Cosma
- Endocrine Research Unit, Department of Internal Medicine, Mayo Medical and Graduate Schools of Medicine, Mayo Clinic, 200 First Street S.W., Rochester, Minnesota 55905, USA
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Ottinger MA, Lavoie E, Thompson N, Barton A, Whitehouse K, Barton M, Abdelnabi M, Quinn M, Panzica G, Viglietti-Panzica C. Neuroendocrine and behavioral effects of embryonic exposure to endocrine disrupting chemicals in birds. ACTA ACUST UNITED AC 2007; 57:376-85. [PMID: 18006066 DOI: 10.1016/j.brainresrev.2007.08.011] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2007] [Revised: 08/26/2007] [Accepted: 08/28/2007] [Indexed: 10/22/2022]
Abstract
Endocrine disrupting chemicals (EDCs) exert hormone-like activity in vertebrates and exposure to these compounds may induce both short- and long-term deleterious effects including functional alterations that contribute to decreased reproduction and fitness. An overview of the effects of a number of EDCs, including androgenic and estrogenic compounds, will be considered. Many studies have been conducted in the precocial Japanese quail, which provides an excellent avian model for testing these compounds. Long-term impacts have also been studied by raising a subset of animals through maturation. The EDCs examined included estradiol, androgen active compounds, soy phytoestrogens, and atrazine. Effects on behavior and hypothalamic neuroendocrine systems were examined. All EDCs impaired reproduction, regardless of potential mechanism of action. Male sexual behavior proved to be a sensitive index of EDC exposure and embryonic exposure to a variety of EDCs consistently resulted in impaired male sexual behavior. Several hypothalamic neural systems proved to be EDC responsive, including arginine vasotocin (VT), catecholamines, and gonadotropin releasing hormone system (GnRH-I). Finally, EDCs are known to impact both the immune and thyroid systems; these effects are significant for assessing the overall impact of EDCs on the fitness of avian populations. Therefore, exposure to EDCs during embryonic development has consequences beyond impaired function of the reproductive axis. In conclusion, behavioral alterations have the advantage of revealing both direct and indirect effects of exposure to an EDC and in some cases can provide a valuable clue into functional deficits at different physiological levels.
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Affiliation(s)
- Mary Ann Ottinger
- Department of Animal and Avian Sciences, University of Maryland College Park, MD 20742, USA.
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29
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Mendez P, Wandosell F, Garcia-Segura LM. Cross-talk between estrogen receptors and insulin-like growth factor-I receptor in the brain: cellular and molecular mechanisms. Front Neuroendocrinol 2006; 27:391-403. [PMID: 17049974 DOI: 10.1016/j.yfrne.2006.09.001] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2006] [Revised: 08/11/2006] [Accepted: 09/01/2006] [Indexed: 01/02/2023]
Abstract
Accumulating evidence suggests that insulin-like growth factor-I (IGF-I) and estradiol interact to regulate neural function. In this review, we focus on the cellular and molecular mechanisms involved in this interaction. The expression of estrogen receptors (ERs) and IGF-I receptor is cross-regulated in the central nervous system and many neurons and astrocytes coexpress both receptors. Furthermore, estradiol activates IGF-I receptor and its intracellular signaling. This effect may involve classical ERs since recent findings suggest that ERalpha may affect IGF-I actions in the brain by a direct interaction with some of the components of IGF-I signaling. In turn, IGF-I may regulate ER transcriptional activity in neuronal cells. In conclusion, ERs appear to be part of the signaling mechanism of IGF-I, and IGF-I receptor part of the mechanism of estradiol signaling in the nervous system.
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Affiliation(s)
- Pablo Mendez
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), E-28002 Madrid, Spain
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30
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Turgeon JL, Carr MC, Maki PM, Mendelsohn ME, Wise PM. Complex actions of sex steroids in adipose tissue, the cardiovascular system, and brain: Insights from basic science and clinical studies. Endocr Rev 2006; 27:575-605. [PMID: 16763155 DOI: 10.1210/er.2005-0020] [Citation(s) in RCA: 188] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Recent publications describing the results of the Women's Health Initiative (WHI) and other studies reporting the impact of hormone therapy on aging women have spurred reexamination of the broad use of estrogens and progestins during the postmenopausal years. Here, we review the complex pharmacology of these hormones, the diverse and sometimes opposite effects that result from the use of different estrogenic and progestinic compounds, given via different delivery routes in different concentrations and treatment sequence, and to women of different ages and health status. We examine our new and growing appreciation of the role of estrogens in the immune system and the inflammatory response, and we pose the concept that estrogen's interface with this system may be at the core of some of the effects on multiple physiological systems, such as the adipose/metabolic system, the cardiovascular system, and the central nervous system. We compare and contrast clinical and basic science studies as we focus on the actions of estrogens in these systems because the untoward effects of hormone therapy reported in the WHI were not expected. The broad interpretation and publicity of the results of the WHI have resulted in a general condemnation of all hormone replacement in postmenopausal women. In fact, careful review of the extensive literature suggests that data resulting from the WHI and other recent studies should be interpreted within the narrow context of the study design. We argue that these results should encourage us to perform new studies that take advantage of a dialogue between basic scientists and clinician scientists to ensure appropriate design, incorporation of current knowledge, and proper interpretation of results. Only then will we have a better understanding of what hormonal compounds should be used in which populations of women and at what stages of menopausal/postmenopausal life.
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Affiliation(s)
- Judith L Turgeon
- Department of Internal Medicine, Division of Endocrinology, Clinical Nutrition, and Vascular Medicine, University of California Davis, Davis, California 95616, USA.
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31
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Mendez P, Garcia-Segura LM. Phosphatidylinositol 3-kinase and glycogen synthase kinase 3 regulate estrogen receptor-mediated transcription in neuronal cells. Endocrinology 2006; 147:3027-39. [PMID: 16497810 DOI: 10.1210/en.2005-1224] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In addition to 17beta-estradiol binding, estrogen receptor (ER) transcriptional activity could be controlled by intracellular kinase signaling pathways activated by growth factors. In this report we present evidence suggesting that glycogen synthase kinase 3 (GSK3), an effector kinase of the phosphatidylinositol 3-kinase (PI3K) pathway, may affect ERalpha activity in N2a neuroblastoma cells. LiCl, sodium valproate, and SB415286, three inhibitors of GSK3, dose-dependently blocked ERalpha-mediated transcription. In contrast, overexpression of wild-type GSK3, but not of a mutant inactive form, increased ER-dependent gene expression. Pharmacological or genetic inhibition of the PI3K/Akt pathway, whose activity is inversely correlated with that of GSK3, increased ERalpha-mediated transcription, and this effect was blocked by GSK3 inhibitors. As in other cell types, IGF-I increased ERalpha activity in absence of estradiol by a mechanism independent of PI3K. In contrast, IGF-I decreased ERalpha activity in the presence of estradiol, and this effect was mediated by PI3K. We also observed a regulated interaction between beta-catenin, one of the main GSK3 nuclear targets, and ERalpha. Transfection with a nondegradable mutant of beta-catenin blocked the increase in ERalpha transcriptional activity induced by the PI3K inhibitor wortmannin, suggesting a role for beta-catenin in estrogen signaling. In addition, we investigated the regulation of ER protein levels as a potential mechanism for its regulation by the PI3K/GSK3 pathway; GSK3 blockade increased ERalpha protein stability, whereas PI3K inhibition decreased it. In summary, our findings suggest that ER-dependent gene expression in N2a cells is controlled by the PI3K/Akt/GSK3 signaling pathway.
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Affiliation(s)
- Pablo Mendez
- Instituto Cajal, Cajero Superior de Investigaciones, E-28002 Madrid, Spain
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32
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Dubal DB, Rau SW, Shughrue PJ, Zhu H, Yu J, Cashion AB, Suzuki S, Gerhold LM, Bottner MB, Dubal SB, Merchanthaler I, Kindy MS, Wise PM. Differential modulation of estrogen receptors (ERs) in ischemic brain injury: a role for ERalpha in estradiol-mediated protection against delayed cell death. Endocrinology 2006; 147:3076-84. [PMID: 16527848 DOI: 10.1210/en.2005-1177] [Citation(s) in RCA: 153] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Estradiol enhances plasticity and survival of the injured brain. Our previous work demonstrates that physiological levels of estradiol protect against cerebral ischemia in the young and aging brain through actions involving estrogen receptors (ERs) and alterations in gene expression. The major goal of this study was to establish mechanisms of neuroprotective actions induced by low levels of estradiol. We first examined effects of estradiol on the time-dependent evolution of ischemic brain injury. Because estradiol is known to influence apoptosis, we hypothesized that it acts to decrease the delayed phase of cell death observed after middle cerebral artery occlusion (MCAO). Furthermore, because ERs are pivotal to neuroprotection, we examined the temporal expression profiles of both ER subtypes, ERalpha and ERbeta, after MCAO and delineated potential roles for each receptor in estradiol-mediated neuroprotection. We quantified cell death in brains at various times after MCAO and analyzed ER expression by RT-PCR, in situ hybridization, and immunohistochemistry. We found that during the first 24 h, the mechanisms of estradiol-induced neuroprotection after MCAO are limited to attenuation of delayed cell death and do not influence immediate cell death. Furthermore, we discovered that ERs exhibit distinctly divergent profiles of expression over the evolution of injury, with ERalpha induction occurring early and ERbeta modulation occurring later. Finally, we provide evidence for a new and functional role for ERalpha in estradiol-mediated protection of the injured brain. These findings indicate that physiological levels of estradiol protect against delayed cell death after stroke-like injury through mechanisms requiring ERalpha.
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Affiliation(s)
- Dena B Dubal
- Department of Physiology, University of Kentucky College of Medicine, Lexington, Kentucky 40536, USA
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33
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Chen WF, Lau WS, Cheung PY, Guo DA, Wong MS. Activation of insulin-like growth factor I receptor-mediated pathway by ginsenoside Rg1. Br J Pharmacol 2006; 147:542-51. [PMID: 16415910 PMCID: PMC1616975 DOI: 10.1038/sj.bjp.0706640] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Ginsenoside Rg1, an active ingredient in ginseng, was previously shown to be a novel class of potent phytoestrogen. The present study aims at investigating the molecular mechanisms involved in mediating its actions in human breast cancer (MCF-7) cells. Rg1 (1 pM) stimulates cell proliferation (P<0.01) and estrogen-responsive pS2 mRNA expression (P<0.05) without alteration of estrogen receptor alpha (ERalpha) protein or mRNA expression in MCF-7 cells. In addition, 10(-14)-10(-4) M of Rg1 does not demonstrate specific binding to ERalpha. We hypothesize that Rg1 may exert its actions in MCF-7 cell via the activation of crosstalk between ER- and insulin growth factor I receptor (IGF-IR)-dependent pathways. The results indicate that Rg1 significantly increases IGF-IR expression and IGF-IR promoter activity in MCF-7 cells (P<0.05). Cotreatment of MCF-7 cells with 1 muM of estrogen antagonist ICI 182,780 completely abolishes the effects of Rg1 on IGF-IR expression.Furthermore, Rg1 enhances tyrosine phosphorylation of IRS-1 in MCF-7 cells upon IGF-I stimulation and the activation of IRS-1 phosphorylation is also ER-dependent. Taken together, our results suggest that Rg1 not only increases IGF-IR expression but also enhances IGF-IR-mediated signaling pathways in MCF-7 cells. The stimulation of IGF-IR expression by Rg1 in MCF-7 cells appears to require ER, and its actions might involve ligand-independent activation of ER.
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Affiliation(s)
- Wen-Fang Chen
- Central Laboratory of the Institute of Molecular Technology for Drug Discovery and Synthesis, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, People's Republic of China
- Department of Physiology, Medical College of Qingdao University, Qingdao 266021, People's Republic of China
| | - Wai-Sum Lau
- Central Laboratory of the Institute of Molecular Technology for Drug Discovery and Synthesis, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, People's Republic of China
- State Key Laboratory of Chinese Medicine and Molecular Pharmacology, Shenzhen 518057, People's Republic of China
| | - Pik-Yuen Cheung
- Central Laboratory of the Institute of Molecular Technology for Drug Discovery and Synthesis, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, People's Republic of China
| | - De-An Guo
- Shanghai Research Center for TCM Modernization, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 201203, People's Republic of China
| | - Man-Sau Wong
- Central Laboratory of the Institute of Molecular Technology for Drug Discovery and Synthesis, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, People's Republic of China
- State Key Laboratory of Chinese Medicine and Molecular Pharmacology, Shenzhen 518057, People's Republic of China
- Author for correspondence:
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Manavathi B, Kumar R. Steering estrogen signals from the plasma membrane to the nucleus: Two sides of the coin. J Cell Physiol 2006; 207:594-604. [PMID: 16270355 DOI: 10.1002/jcp.20551] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Estrogen mediate its biological effects through its association with estrogen receptors (ERs). They also regulate the expression of a variety of genes involved in distinct physiological processes, including development, metabolism, and reproduction. In addition, emerging data suggest that the estrogen-estrogen receptor complex can also function as a cytoplasmic signaling molecule and may influence processes such as cardiovascular protection, bone preservation, neuroprotection, and proliferation of various cell types. Such extranuclear or nongenomic signaling pathways are rapid and supposedly independent of transcription. A recent exciting finding was that G-coupled membrane protein receptor, GPR30, an alternative to the classical ERs, is also involved in the rapid signaling of estrogen through its direct association with estrogen. These new findings combined with the recent advances in the cytoplasmic functions of proline, glutamic acid, luecine rich protein 1 (PELP1), and metastatic tumor antigen 1 short form (MTA1s) have opened a new spectrum and raised several new concerns in the field of estrogen biology and put the attention to unveil many unknown mechanistic actions of estrogen in cellular physiology. In this review, we briefly summarize what is currently known of the cellular mechanisms and physiology of estrogen's nongenomic actions in various cellular systems used by ERs.
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35
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Mendez P, Cardona-Gomez GP, Garcia-Segura LM. Interactions of insulin-like growth factor-I and estrogen in the brain. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2005; 567:285-303. [PMID: 16370144 DOI: 10.1007/0-387-26274-1_12] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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36
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Veldhuis JD, Erickson D, Iranmanesh A, Miles JM, Bowers CY. Sex-steroid control of the aging somatotropic axis. Endocrinol Metab Clin North Am 2005; 34:877-93, viii. [PMID: 16310628 DOI: 10.1016/j.ecl.2005.07.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Johannes D Veldhuis
- Endocrine Research Unit, Department of Internal Medicine, Mayo School of Graduate Medical Education, General Clinical Research Center, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
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37
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Amantea D, Russo R, Bagetta G, Corasaniti MT. From clinical evidence to molecular mechanisms underlying neuroprotection afforded by estrogens. Pharmacol Res 2005; 52:119-32. [PMID: 15967377 DOI: 10.1016/j.phrs.2005.03.002] [Citation(s) in RCA: 153] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2005] [Accepted: 03/14/2005] [Indexed: 11/15/2022]
Abstract
Recent studies have highlighted that female sex hormones represent potential neuroprotective agents against damage produced by acute and chronic injuries in the adult brain. Clinical reports have documented the effectiveness of estrogens to attenuate symptoms associated with Parkinson's disease, and to reduce the risk of Alzheimer's disease and cerebrovascular stroke. This evidence is corroborated by numerous experimental studies documenting the protective role of female sex hormones both in vitro and in vivo. Accordingly, estrogens have been shown to promote survival and differentiation of several neuronal populations maintained in culture, and to reduce cell death associated with excitotoxicity, oxidative stress, serum deprivation or exposure to beta-amyloid. The neuroprotective effects of estrogens have been widely documented in animal models of neurological disorders, such as Alzheimer's and Parkinson's diseases, as well as cerebral ischemia. Although estrogens are known to exert several direct effects on neurones, the cellular and molecular mechanisms implicated in their protective actions on the brain are not completely understood. Thus, on the basis of clinical and experimental evidence, in this review, we discuss recent findings concerning the neuronal effects of estrogens that may contribute to their neuroprotective actions. Both estrogen receptor-dependent and -independent mechanisms will be described. These include modulation of cell death regulators, such as Bcl-2, Akt and calpain, as well as interaction with growth factors, such as BDNF, NGF, IGF-I and their receptors. The anti-inflammatory effects of estrogens will also be described, namely their ability to reduce brain levels of inflammatory mediators, cytokines and chemokines. Finally, a brief overview about receptor-independent mechanisms of neuroprotection will aim at describing the antioxidant effects of estrogens, as well as their ability to modulate neurotransmission.
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Affiliation(s)
- Diana Amantea
- Department of Pharmacobiology, University of Calabria, Via P. Bucci, Ed. Polifunzionale, Arcavacata di Rende (CS), Italy
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Alvarez-de-la-Rosa M, Silva I, Nilsen J, Pérez MM, García-Segura LM, Avila J, Naftolin F. Estradiol Prevents Neural Tau Hyperphosphorylation Characteristic of Alzheimer's Disease. Ann N Y Acad Sci 2005; 1052:210-24. [PMID: 16024764 DOI: 10.1196/annals.1347.016] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Alzheimer's disease (AD) is three times more prevalent in women than men, and epidemiological studies have shown that estrogen replacement in aging women forestalls the onset of AD. Hyperphosphorylation of the tau protein that forms the neurofibrillary tangles found in AD brains might be responsible for the breakdown of microtubules in affected neurons. The mechanisms by which tau protein is phosphorylated in the AD brain are not fully understood. Using a human neuroblastoma cell line (SH-SY5Y) and primary cultures of newborn male or female rat cerebral cortical neurons, we investigated the effect of 17beta-estradiol on tau protein expression and phosphorylation. We found that estradiol increased total tau and induced dephosphorylation at the proline-directed site of the molecule. Further, estradiol prevented okadaic acid-induced hyperphosphorylation of tau in both proline- and non-proline-directed sites, and antiestrogens blocked this effect. To our knowledge, this is the first report of an effect of estradiol on naturally occurring and induced tau phosphorylation. This assumes special significance because the estrogen action was found to be sexually dimorphic in rat cortical neurons and differentiation-sensitive in human neuroblastoma cells.
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Veiga S, Melcangi RC, Doncarlos LL, Garcia-Segura LM, Azcoitia I. Sex hormones and brain aging. Exp Gerontol 2005; 39:1623-31. [PMID: 15582278 DOI: 10.1016/j.exger.2004.05.008] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2004] [Accepted: 05/17/2004] [Indexed: 02/07/2023]
Abstract
Sex steroids exert pleiotropic effects in the nervous system, preserving neural function and promoting neuronal survival. Therefore, the age-related decrease in sex steroids may have a negative impact on neural function. Progesterone, testosterone and estradiol prevent neuronal loss in the central nervous system in different experimental animal models of neurodegeneration. Furthermore, progesterone and its reduced derivatives dihydroprogesterone and tetrahydroprogesterone reduce aging-associated morphological abnormalities of myelin and aging-associated myelin fiber loss in rat peripheral nerves. However, the results from hormone replacement studies in humans are thus far inconclusive. A possible alternative to hormonal replacement therapy is to increase local steroidogenesis by neural tissues, which express enzymes for steroid synthesis and metabolism. Proteins involved in the intramitochondrial trafficking of cholesterol, the first step in steroidogenesis, such as the peripheral-type benzodiazepine receptor and the steroidogenic acute regulatory protein, are up-regulated in the nervous system after injury. Furthermore, steroidogenic acute regulatory protein expression is increased in the brain of 24-month-old rats compared with young adult rats. This suggests that brain steroidogenesis may be modified in adaptation to neurodegenerative conditions and to the brain aging process. Furthermore, recent studies have shown that local formation of estradiol in the brain, by the enzyme aromatase, is neuroprotective. Therefore, steroidogenic acute regulatory protein, peripheral-type benzodiazepine receptor and aromatase are attractive pharmacological targets to promote neuroprotection in the aged brain.
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Affiliation(s)
- Sergio Veiga
- Instituto Cajal, CSIC, Avenida Doctor Arce 37, 28002 Madrid, Spain
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Topalli I, Etgen AM. Insulin-like growth factor-I receptor and estrogen receptor crosstalk mediates hormone-induced neurite outgrowth in PC12 cells. Brain Res 2005; 1030:116-24. [PMID: 15567343 DOI: 10.1016/j.brainres.2004.09.057] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2004] [Indexed: 01/08/2023]
Abstract
Estradiol (E(2)) and insulin-like growth factor-I (IGF-I) can act independently or in concert to promote neurite outgrowth in vivo and in cultured neurons. This study examined the role of crosstalk between estrogen receptor (ER)alpha and the IGF-I receptor as a critical mediator of hormone- and growth factor-dependent neurite outgrowth in a homogenous cell system. We used control PC12 cells and PC12 cells stably transfected with ER alpha, both of which express IGF-I receptor. Cells were treated for 1 week with vehicle, 1 nM E(2) or 100 ng/ml IGF-I alone or with E(2) or IGF-I in the presence of either the IGF-I receptor antagonist JB1 or the ER antagonist ICI 182,780. IGF-I significantly increased neurite outgrowth, as measured by the percentage of process-bearing cells, and absolute neurite length per cell in both control and ER alpha-transfected PC12 cells. In contrast, E(2) increased process formation and extension only in PC12 cells that were stably transfected with ER alpha. ICI 182,780 and JB1 blocked the IGF-I-induced increases in neurite length in both cell types. The efficacy of ICI 182,780 in control PC12 cells may have been due to the upregulation of ER alpha in these cells by the 7-day treatment with IGF-I. The ER and IGF-I receptor antagonists similarly blocked the E(2)-induced increase in neurite lengths in ER alpha-transfected cells. Immunofluorescent analysis of the cellular distribution of an axonal marker, phospho-neurofilament, verified that the processes extended by PC12 cells were neurites. These data suggest that receptor crosstalk between IGF-I receptors and ER alpha has an important role in neurite formation and extension even in a single-cell system.
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Affiliation(s)
- Ilir Topalli
- Department of Neuroscience, Forchheimer 113, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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Reyna-Neyra A, Arias C, Ferrera P, Morimoto S, Camacho-Arroyo I. Changes in the content and distribution of microtubule associated protein 2 in the hippocampus of the rat during the estrous cycle. ACTA ACUST UNITED AC 2004; 60:473-80. [PMID: 15307151 DOI: 10.1002/neu.20042] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The molecular mechanisms involved in the regulation of synaptic plasticity in the hippocampus during the estrous cycle of the rat are not completely understood. Because this process implicates changes in neuronal cytoskeleton organization, we analyzed the content of microtubule associated protein 2 (MAP2) and Tau in the hippocampus and the frontal cortex of the rat by Western blot, as well as the hippocampal distribution of MAP2 during the estrous cycle by immunohistochemistry. In the hippocampus the lowest content of MAP2 was found on diestrus day, and it significantly increased at proestrus. This increase was maintained on estrus and metestrus days. In the frontal cortex MAP2 content did not significantly change during the estrous cycle. In contrast, the content of Tau did not vary during the estrous cycle in either the hippocampus or the frontal cortex. The immunohistochemical analysis showed an increase in dendrite thickness and in dendritic branching in the CA1 region on proestrus day, as well as an aggregation of MAP2 in apical dendrites near to pyramidal somata on this day in comparison with diestrus. We suggest that changes in the content and neuronal distribution of MAP2 are involved in the structural changes that occur in the hippocampus of the rat during the estrous cycle, and that these variations are related to changes in estradiol and progesterone levels.
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Affiliation(s)
- Andrea Reyna-Neyra
- Departamento de Biología, Facultad de Química, Universidad Nacional Autónoma de México, 04510 México D.F., México
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El-Bakri NK, Islam A, Suliman I, Lindgren U, Winblad B, Adem A. Ovariectomy and gonadal hormone treatment: effects on insulin-like growth factor-1 receptors in the rat brain. Growth Horm IGF Res 2004; 14:388-393. [PMID: 15336232 DOI: 10.1016/j.ghir.2004.04.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2003] [Revised: 04/27/2004] [Accepted: 04/28/2004] [Indexed: 02/04/2023]
Abstract
Various studies demonstrate that estradiol regulates structure and function of adult neurons. Long-term effect of estradiol in terms of neuroprotection is less documented compared to short-term one. It is well documented that estradiol interacts with insulin-like growth factor-1 (IGF-I) in the brain. The present study examines the effect of ovariectomy and two doses of ovarian hormone treatment on IGF-I receptor density in the adult rat by receptor autoradiography using (125)I-IGF-I as a ligand. Our result showed that ovariectomy decreased IGF-I receptor density in hippocampus, hypothalamus and parietal cortex compared to that of the sham-operated group. Treatment with low or high dose estrogen restored IGF-I receptor density to the control levels in nearly all areas studied in this investigation. It seems that low dose estrogen has more pronounced effect than the high dose in restoring IGF-I receptor density. On the other hand, progesterone treatment in high but not in low dose restored IGF-I receptor density to that of the control. These results demonstrate that both estrogen and progesterone significantly affects IGF-I receptor density in different areas of the brain. These effects indicate a dose-dependent modulator effect of ovarian hormones on IGF-I activity in the brain.
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Affiliation(s)
- Nahid K El-Bakri
- Neurotec, Section of Experimental Geriatrics, Karolinska Institute, Huddinge University Hospital, B-84 S-141 86 Huddinge, Sweden.
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Brito VI, Carrer HF, Cambiasso MJ. Inhibition of tyrosine kinase receptor type B synthesis blocks axogenic effect of estradiol on rat hypothalamic neurones in vitro. Eur J Neurosci 2004; 20:331-7. [PMID: 15233742 DOI: 10.1111/j.1460-9568.2004.03485.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
17-beta-estradiol (E2) increases axonal growth and tyrosine kinase receptor (Trk)B levels of male-derived hypothalamic neurones in vitro. To investigate whether the axogenic response depends on the upregulation of TrkB, we analysed neuritic growth and neuronal polarization in cultures treated with an antisense oligonucleotide against TrkB mRNA. In cultures without E2, treatment with 7.5 or 10 micro m antisense reduced TrkB levels and the percentage of neurones showing an identifiable axon; the number and length of minor processes were increased. In cultures treated with 5 micro m antisense, morphometric parameters were normal although total TrkB levels were reduced. The same dose prevented the E2-dependent increase of TrkB levels and suppressed the axogenic effect of E2. These results indicate that TrkB is necessary for normal neuronal growth and maturation and further suggest that an increase in TrkB is necessary for E2 to exert its axogenic effect in male-derived neurones.
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Affiliation(s)
- V I Brito
- Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC-CONICET, Casilla de Correo 389, 5000 Córdoba, Argentina
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Hiney JK, Srivastava V, Dearth RK, Dees WL. Influence of estradiol on insulin-like growth factor-1-induced luteinizing hormone secretion. Brain Res 2004; 1013:91-7. [PMID: 15196971 DOI: 10.1016/j.brainres.2004.03.054] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/31/2004] [Indexed: 12/01/2022]
Abstract
Several studies suggest an interrelationship between estradiol (E2) and insulin-like growth factor-1 (IGF-1) at the hypothalamic level. The present study was designed to discern if the capability of IGF-1 to release LH and influence the timing of female puberty is influenced by E2. Twenty-eight-day-old female rats were ovariectomized (OVEX), then implanted with a third ventricular (3V) cannula. Two weeks later, these animals received subcutaneous (s.c.) injection of oil, or either one or two injections of E2 in the form of estradiol benzoate (1 microg). Forty-eight hours later, four basal blood samples were drawn then the animals received IGF-1 (200 ng) or saline via the 3V and four more blood samples were taken. Results indicated that E2 replacement lowered basal LH levels and IGF-1 induced a significant LH release in only animals that had E2 levels above 20 pg/ml. These levels of E2 were also associated with increases (p<0.05) in the expression of both IGF-1 receptor (IGF-1R) mRNA and protein. In order to further support the hypothesis that the action of IGF-1 at the time of puberty is influenced by E2, 24-day-old intact female rats received s.c. injection of sesame oil or 0.1 microg of E2. The next day, the E2-treated animals also received twice daily s.c. injections of either IGF-1 (500 ng) or saline until vaginal opening (VO) occurred. The animals that received E2 plus IGF-1 showed VO at 31.1 days, which was 2.5 days earlier (p<0.01) than E2-treated animals and 4 days earlier (p<0.001) than IGF-1-treated and saline control animals. Taken together, these results indicate that the hypothalamic action of IGF-1 to stimulate LH release and advance female pubertal development is dependent upon the influence of E2.
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Affiliation(s)
- Jill K Hiney
- Department of Veterinary Anatomy and Public Health, College of Veterinary Medicine, Texas A&M University, College Station, TX, 77843-4458, USA
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Cardona-Gomez P, Perez M, Avila J, Garcia-Segura LM, Wandosell F. Estradiol inhibits GSK3 and regulates interaction of estrogen receptors, GSK3, and beta-catenin in the hippocampus. Mol Cell Neurosci 2004; 25:363-73. [PMID: 15033165 DOI: 10.1016/j.mcn.2003.10.008] [Citation(s) in RCA: 149] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2003] [Revised: 09/24/2003] [Accepted: 10/07/2003] [Indexed: 12/25/2022] Open
Abstract
Estrogens regulate a wide set of neuronal functions such as gene expression, survival and differentiation in a manner not very different from that exerted by neurotrophins or by growth factors. The best-studied hormonal action is the transcriptional activation mediated by estrogen receptors. However, the direct effects of estrogen on growth factor signaling have not been well clarified. The present data show that estradiol, in vivo, induces a transient activation of GSK3 in the adult female rat hippocampus, followed by a more sustained inhibition, as inferred from phosphorylation levels of Tau. Similar data was obtained from cultured hippocampal neurons when treated with the hormone. The transient activation was confirmed by direct measure of GSK3 kinase activity. In addition, our results show a novel complex of estrogen receptor alpha, GSK3, and beta-catenin. The presence of the hormone removes beta-catenin from this complex. There is a second complex, also affected by estradiol, in which Tau is associated with GSK3, beta-catenin, and elements of the PI3 kinase complex. Considering the role of GSK3 in neurodegeneration, our data suggest that part of the neuroprotective effects of estrogen may be due to the control of GSK3.
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Affiliation(s)
- P Cardona-Gomez
- Centro de Biología Molecular Severo Ochoa CSIC-Universidad Autónoma de Madrid, Madrid 28049, Spain
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Abstract
The ovarian steroid hormones have numerous effects on the brain, many of which are mediated, at least in part, by interaction with intracellular steroid hormone receptors acting as regulators of transcription. These intracellular steroid hormone receptors have often been considered to be activated solely by cognate hormone. However, during the past decade, numerous studies have shown that the receptors can be activated by neurotransmitters and intracellular signaling systems, through a process that does not require hormone. Although most of these have been in vitro experiments, others have been in vivo. Evidence from a wide variety of tissues and cells suggests that steroid hormone receptors are transcription factors that can be activated by a wide variety of factors, only one of which is cognate hormone. Furthermore, ligand-independent activation of neural steroid hormone receptors, rather than being a pharmacological or in vitro curiosity, seems to be a process that occurs in the normal physiology of animals. Thinking of steroid hormone receptors only as ligand-activated proteins may constrain our thinking about the many factors that may activate the receptors and cause receptor-dependent changes in neural gene expression and neuroendocrine function.
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Affiliation(s)
- Jeffrey D Blaustein
- Center for Neuroendocrine Studies, University of Massachusetts, Amherst, Massachusetts 01003, USA.
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Quesada A, Micevych PE. Estrogen interacts with the IGF-1 system to protect nigrostriatal dopamine and maintain motoric behavior after 6-hydroxdopamine lesions. J Neurosci Res 2004; 75:107-16. [PMID: 14689453 DOI: 10.1002/jnr.10833] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The most prominent neurochemical hallmark of Parkinson's disease (PD) is the loss of nigrostriatal dopamine (DA). Animal models of PD have concentrated on depleting DA and therapies have focused on maintaining or restoring DA. Within this context estrogen protects against 6-hydroxdopamine (6-OHDA) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) lesions of the nigrostriatal DA pathway. Present studies tested the hypothesis that neuroprotective estrogen actions involve activation of the insulin-like growth factor-1 (IGF-1) system. Ovariectomized rats were treated with either a single subcutaneous injection of 17beta-estradiol benzoate or centrally or peripherally IGF-1. All rats were infused unilaterally with 6-OHDA into the medial forebrain bundle (MFB) to lesion the nigrostriatal DA pathway. Tyrosine hydroxylase (TH) immunocytochemistry confirmed that rats injected with 6-OHDA had a massive loss of TH immunoreactivity in both the ipsilateral substantia nigra compacta (60% loss) and the striatum (>95% loss) compared to the contralateral side. Loss of TH immunoreactivity was correlated with loss of asymmetric forelimb movements, a behavioral assay for motor deficits. Pretreatment with estrogen or IGF-1 significantly prevented 6-OHDA-induced loss of substantia nigra compacta neurons (20% loss) and TH immunoreactivity in DA fibers in the striatum (<20% loss) and prevented the loss of asymmetric forelimb use. Blockage of IGF-1 receptors by intracerebroventricular JB-1, an IGF-1 receptor antagonist, attenuated both estrogen and IGF-1 neuroprotection of nigrostriatal DA neurons and motor behavior. These findings suggest that IGF-1 and estrogen acting through the IGF-1 system may be critical for neuroprotective effects of estrogen on nigrostriatal DA neurons in this model of PD.
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Affiliation(s)
- Arnulfo Quesada
- Department of Neurobiology, Laboratory of Neuroendocrinology, Brain Research Institute, David Geffen School of Medicine UCLA, Los Angeles, California 90095-1763, USA.
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Abstract
The ovarian hormone 17beta-estradiol (E2) is neuroprotective in animal models of neurodegenerative diseases. Some studies suggest that the neuroprotective effects of 17beta-estradiol are a consequence of its antioxidant activity that depend on the hydroxyl group in the C3 position of the A ring. As in other tissues, 17beta-estradiol is metabolized in the brain to 2-hydroxyestradiol (2OHE2) and 2-methoxyestradiol (2MEOHE2). These two molecules present the hydroxyl group in the A ring and have a higher antioxidant activity than 17beta-estradiol. To test the hypothesis that conversion to 2-hydroxyestradiol and 2-methoxyestradiol may mediate neuroprotective actions of 17beta-estradiol in vivo, we have assessed whether these molecules protect hilar hippocampal neurons from kainic acid toxicity. Ovariectomized Wistar rats received an i.p. injection of 1, 10 or 100 microg 17beta-estradiol, 2-hydroxyestradiol or 2-methoxyestradiol followed by an i.p. injection of kainic acid (7 mg/kg) or vehicle. Treatment with kainic acid resulted in a significant loss of hilar neurons. Only the highest dose tested of 17beta-estradiol (100 microg/rat) prevented kainic acid-induced neuronal loss. 2-Hydroxyestradiol and 2-methoxyestradiol did not protect hilar neurons from kainic acid, suggesting that the mechanism of neuroprotection by 17beta-estradiol in vivo is not mediated by its metabolism to catecholestrogens or methoxycatecholestrogens. Furthermore, 2-methoxyestradiol (100 microg/rat), by itself, resulted in a significant neuronal loss in the hilus that was detected 96 h after the treatment with the steroid. This finding suggests that endogenous metabolism of 17beta-estradiol to 2-methoxyestradiol may counterbalance the neuroprotective effects of the hormone.
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Affiliation(s)
- Ofir Picazo
- Escuela Superior de Medicina del Instituto Politécnico Nacional, Plan de San Luis y Diaz Mirón Col. Sto. Tomás 11340, México D.F., Mexico
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Haynes LE, Lendon CL, Barber DJ, Mitchell IJ. 17 Beta-oestradiol attenuates dexamethasone-induced lethal and sublethal neuronal damage in the striatum and hippocampus. Neuroscience 2003; 120:799-806. [PMID: 12895519 DOI: 10.1016/s0306-4522(03)00167-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Abnormal corticosteroid release is extensively associated with mood disorders. This association may result from the toxic actions of endogenous corticosteroids which can induce apoptosis of hippocampal neurons. Similarly, dexamethasone, a synthetic corticosteroid, can induce lethal and sublethal damage to rat hippocampal and striatal neurons and can result in steroid-induced psychoses in humans. The experiments reported here tested the hypothesis that pre-treatment with oestrogen would also attenuate dexamethasone-induced neuronal damage as oestrogens have neuroprotective actions against a variety of insults and falling levels of oestrogen are associated with increased vulnerability to mood disorders. Male Sprague-Dawley rats received three systemic injections which were a combination of vehicle, 17-beta-oestradiol (0.2 mg/kg, s.c.), the oestrogen receptor antagonist tamoxifen (10 mg/kg, s.c.) and dexamethasone (0.7 mg/kg, i.p.) and were killed 24 h after the final injection. Injections of dexamethasone (when preceded by vehicle injections) resulted in elevated levels of apoptosis and sub-lethal damage, as demonstrated by reduced levels of microtubule-associated protein-2-immunopositive neurons, in the striatum and hippocampus. This damage was regional with the dorsomedial caudate putamen and the dentate gyrus and CA1 and CA3 hippocampal sub-fields being particularly affected. Pretreatment with oestrogen substantially attenuated the dexamethasone-induced neuronal damage. This oestrogen-induced neuronal protection was in turn virtually eliminated by giving an initial injection of tamoxifen. These results suggest, therefore, that oestrogens can protect from corticosteroid-induced neuronal damage via an oestrogen receptor-mediated process.
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Affiliation(s)
- L E Haynes
- School of Biomedical Sciences, The Medical School, Queens Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK.
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Carrer HF, Cambiasso MJ, Brito V, Gorosito S. Neurotrophic Factors and Estradiol Interact To Control Axogenic Growth in Hypothalamic Neurons. Ann N Y Acad Sci 2003; 1007:306-16. [PMID: 14993063 DOI: 10.1196/annals.1286.029] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Previous work from our laboratory has shown that in cultures of hypothalamic neurons obtained from male fetuses at embryonic day 16, the axogenic response to estrogen (E2) is contingent on coculture with target glia or target glia-conditioned media (CM). Neither the estrogen receptor blockers tamoxifen nor ICI 182,780 prevented the axogenic effects of the hormone. Estradiol made membrane-impermeable by conjugation to a protein of high molecular weight (E2-BSA) preserved its axogenic capacity, suggesting the possibility of a membrane effect responsible for the action of E2. Western blot analysis of extracts from homogenates of cultured neurons grown with E2 and CM from target glia had more TrkB than cultures with CM alone or E2 alone. To further investigate the interaction between E2 and the neurotrophin receptors, we used a specific antisense oligonucleotide (AS) to prevent the estradiol-induced increase of TrkB. The effect of E2 was suppressed in cultures in which TrkB was down-regulated by the AS, showing decreased axonal elongation when compared with neurons treated with E2 without AS or with sense TrkB. In cultures grown with AS, the axonal length of E2-treated cultures was not different from cultures without E2. Evidence suggesting cross-talk between E2 and neurotrophic factor(s) prompted investigation of signaling along the MAPK cascade. Immuno blotting of E2-treated cultures showed increased levels of phosphorylated ERK1 and ERK2. UO126 but not LY294002 blocked E2-induced axonal elongation, suggesting that the MAPKs are involved in this response.
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Affiliation(s)
- H F Carrer
- Instituto de Investigación Médica M. y M. Ferreyra, INIMEC-CONICET, Casilla de Correo 389, 5000 Cordóba, Argentina.
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