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Tang J, Mou M, Zheng X, Yan J, Pan Z, Zhang J, Li B, Yang Q, Wang Y, Zhang Y, Gao J, Li S, Yang H, Zhu F. Strategy for Identifying a Robust Metabolomic Signature Reveals the Altered Lipid Metabolism in Pituitary Adenoma. Anal Chem 2024; 96:4745-4755. [PMID: 38417094 DOI: 10.1021/acs.analchem.3c03796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2024]
Abstract
Despite the well-established connection between systematic metabolic abnormalities and the pathophysiology of pituitary adenoma (PA), current metabolomic studies have reported an extremely limited number of metabolites associated with PA. Moreover, there was very little consistency in the identified metabolite signatures, resulting in a lack of robust metabolic biomarkers for the diagnosis and treatment of PA. Herein, we performed a global untargeted plasma metabolomic profiling on PA and identified a highly robust metabolomic signature based on a strategy. Specifically, this strategy is unique in (1) integrating repeated random sampling and a consensus evaluation-based feature selection algorithm and (2) evaluating the consistency of metabolomic signatures among different sample groups. This strategy demonstrated superior robustness and stronger discriminative ability compared with that of other feature selection methods including Student's t-test, partial least-squares-discriminant analysis, support vector machine recursive feature elimination, and random forest recursive feature elimination. More importantly, a highly robust metabolomic signature comprising 45 PA-specific differential metabolites was identified. Moreover, metabolite set enrichment analysis of these potential metabolic biomarkers revealed altered lipid metabolism in PA. In conclusion, our findings contribute to a better understanding of the metabolic changes in PA and may have implications for the development of diagnostic and therapeutic approaches targeting lipid metabolism in PA. We believe that the proposed strategy serves as a valuable tool for screening robust, discriminating metabolic features in the field of metabolomics.
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Affiliation(s)
- Jing Tang
- College of Pharmaceutical Sciences, The Second Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang University, Hangzhou 310058, China
- Department of Bioinformatics, Chongqing Medical University, Chongqing 400016, China
| | - Minjie Mou
- College of Pharmaceutical Sciences, The Second Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang University, Hangzhou 310058, China
| | - Xin Zheng
- Multidisciplinary Center for Pituitary Adenoma of Chongqing, Department of Neuosurgery, Xinqiao Hospital, Army Medical University, Chongqing 400037, China
| | - Jin Yan
- Multidisciplinary Center for Pituitary Adenoma of Chongqing, Department of Neuosurgery, Xinqiao Hospital, Army Medical University, Chongqing 400037, China
| | - Ziqi Pan
- College of Pharmaceutical Sciences, The Second Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang University, Hangzhou 310058, China
| | - Jinsong Zhang
- College of Pharmaceutical Sciences, The Second Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang University, Hangzhou 310058, China
| | - Bo Li
- School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, China
| | - Qingxia Yang
- School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, China
| | - Yunxia Wang
- College of Pharmaceutical Sciences, The Second Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang University, Hangzhou 310058, China
| | - Ying Zhang
- College of Pharmaceutical Sciences, The Second Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang University, Hangzhou 310058, China
| | - Jianqing Gao
- College of Pharmaceutical Sciences, The Second Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang University, Hangzhou 310058, China
| | - Song Li
- Multidisciplinary Center for Pituitary Adenoma of Chongqing, Department of Neuosurgery, Xinqiao Hospital, Army Medical University, Chongqing 400037, China
| | - Hui Yang
- Multidisciplinary Center for Pituitary Adenoma of Chongqing, Department of Neuosurgery, Xinqiao Hospital, Army Medical University, Chongqing 400037, China
| | - Feng Zhu
- College of Pharmaceutical Sciences, The Second Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang University, Hangzhou 310058, China
- Innovation Institute for Artificial Intelligence in Medicine of Zhejiang University, Alibaba-Zhejiang University Joint Research Center of Future Digital Healthcare, Hangzhou 330110, China
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Ouyang Q, Hu S, Li L, Ran M, Zhu J, Zhao Y, Hu B, Hu J, He H, Li L, Wang J. Integrated mRNA and miRNA transcriptome analysis provides novel insights into the molecular mechanisms underlying goose pituitary development during the embryo-to-hatchling transition. Poult Sci 2021; 100:101380. [PMID: 34358958 PMCID: PMC8350522 DOI: 10.1016/j.psj.2021.101380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 07/01/2021] [Accepted: 07/04/2021] [Indexed: 11/25/2022] Open
Abstract
It is well established that the endocrine system plays a pivotal role in preparing the avian embryos for the abrupt switch from chorioallantoic to pulmonary respiration during the critical embryo-to-hatchling transition. However, as the master gland of the endocrine system, there has been little research focusing on the molecular mechanisms controlling the development and function of the pituitary gland during the peri-hatch period in birds. In the present study, we aimed to determine the genome-wide mRNA and miRNA transcriptome profiles of the pituitary during the embryo-to-hatchling transition period from embryonic day 22 (E22) to post-hatching day 6 (P6) in the goose (Anser cygnoides). Of note, expression of Anser_cygnoides_newGene_32456 and LOC106031011 were significantly different among these 4 stages (i.e., E22, E26, P2, and P6). Meanwhile, the neuroactive ligand-receptor interaction pathway was significantly enriched by the DEGs commonly identified among three pairwise comparisons. At the miRNA transcriptome level, there were not commonly identified DE miRNAs among these 4 stages, while the 418 of their predicted target genes were mutually shared. Both the target genes of DE miRNAs in each comparison and these 418 shared target genes were significantly enriched in the ECM-receptor interaction and focal adhesion pathways. In the predicted miRNA-mRNA interaction networks of these 2 pathways, novel_miRNA_467, novel_miRNA_154, and novel_miRNA_340 were the hub miRNAs. In addition, multiple DE miRNAs also showed predicted target relationships with the DEGs associated with extracellular matrix (ECM) components. Among them, expression of novel_miR_120, tgu-miR-92-3p, and novel_miR_398 was significantly negatively correlated with that of LAMC3 (laminin subunit gamma3), suggesting that these miRNAs may regulate pituitary tissue remodeling and functional changes through targeting LAMC3 during development. These identified DE mRNAs and miRNAs as well as their predicted interaction networks involved in regulation of tissue remodeling and cellular functions were most likely to play critical roles in facilitating the embryo-to-hatchling transition. These results provide novel insights into the early developmental process of avian pituitary gland and will help better understand the underlying molecular mechanisms.
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Affiliation(s)
- Qingyuan Ouyang
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China
| | - Shenqiang Hu
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China.
| | - Li Li
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China
| | - Mingxia Ran
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China
| | - Jiaran Zhu
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China
| | - Yiting Zhao
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China
| | - Bo Hu
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China
| | - Jiwei Hu
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China
| | - Hua He
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China
| | - Liang Li
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China
| | - Jiwen Wang
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China
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Zhao M, Scott S, Evans KW, Yuca E, Saridogan T, Zheng X, Wang H, Korkut A, Cruz Pico CX, Demirhan M, Kirby B, Kopetz S, Diala I, Lalani AS, Piha-Paul S, Meric-Bernstam F. Combining Neratinib with CDK4/6, mTOR, and MEK Inhibitors in Models of HER2-positive Cancer. Clin Cancer Res 2021; 27:1681-1694. [PMID: 33414137 PMCID: PMC8075007 DOI: 10.1158/1078-0432.ccr-20-3017] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 10/16/2020] [Accepted: 12/23/2020] [Indexed: 11/16/2022]
Abstract
PURPOSE Neratinib is an irreversible, pan-HER tyrosine kinase inhibitor that is FDA approved for HER2-overexpressing/amplified (HER2+) breast cancer. In this preclinical study, we explored the efficacy of neratinib in combination with inhibitors of downstream signaling in HER2+ cancers in vitro and in vivo. EXPERIMENTAL DESIGN Cell viability, colony formation assays, and Western blotting were used to determine the effect of neratinib in vitro. In vivo efficacy was assessed with patient-derived xenografts (PDX): two breast, two colorectal, and one esophageal cancer (with HER2 mutations). Four PDXs were derived from patients who received previous HER2-targeted therapy. Proteomics were assessed through reverse phase protein arrays and network-level adaptive responses were assessed through Target Score algorithm. RESULTS In HER2+ breast cancer cells, neratinib was synergistic with multiple agents, including mTOR inhibitors everolimus and sapanisertib, MEK inhibitor trametinib, CDK4/6 inhibitor palbociclib, and PI3Kα inhibitor alpelisib. We tested efficacy of neratinib with everolimus, trametinib, or palbociclib in five HER2+ PDXs. Neratinib combined with everolimus or trametinib led to a 100% increase in median event-free survival (EFS; tumor doubling time) in 25% (1/4) and 60% (3/5) of models, respectively, while neratinib with palbociclib increased EFS in all five models. Network analysis of adaptive responses demonstrated upregulation of EGFR and HER2 signaling in response to CDK4/6, mTOR, and MEK inhibition, possibly providing an explanation for the observed synergies with neratinib. CONCLUSIONS Taken together, our results provide strong preclinical evidence for combining neratinib with CDK4/6, mTOR, and MEK inhibitors for the treatment of HER2+ cancer.
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Affiliation(s)
- Ming Zhao
- Department of Investigational Cancer Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Stephen Scott
- Department of Investigational Cancer Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Kurt W Evans
- Department of Investigational Cancer Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Erkan Yuca
- Department of Investigational Cancer Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Turcin Saridogan
- Department of Investigational Cancer Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Xiaofeng Zheng
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Heping Wang
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Anil Korkut
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Christian X Cruz Pico
- Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Mehmet Demirhan
- Department of Investigational Cancer Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Bryce Kirby
- Department of Investigational Cancer Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Scott Kopetz
- Department of Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | | | | | - Sarina Piha-Paul
- Department of Investigational Cancer Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Funda Meric-Bernstam
- Department of Investigational Cancer Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas.
- Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
- Department of Breast Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
- Institute of Personalized Cancer Therapy, The University of Texas MD Anderson Cancer Center, Houston, Texas
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Zemková H, Stojilkovic SS. Neurotransmitter receptors as signaling platforms in anterior pituitary cells. Mol Cell Endocrinol 2018; 463:49-64. [PMID: 28684290 PMCID: PMC5752632 DOI: 10.1016/j.mce.2017.07.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 06/29/2017] [Accepted: 07/02/2017] [Indexed: 02/07/2023]
Abstract
The functions of anterior pituitary cells are controlled by two major groups of hypothalamic and intrapituitary ligands: one exclusively acts on G protein-coupled receptors and the other activates both G protein-coupled receptors and ligand-gated receptor channels. The second group of ligands operates as neurotransmitters in neuronal cells and their receptors are termed as neurotransmitter receptors. Most information about pituitary neurotransmitter receptors was obtained from secretory studies, RT-PCR analyses of mRNA expression and immunohistochemical and biochemical analyses, all of which were performed using a mixed population of pituitary cells. However, recent electrophysiological and imaging experiments have characterized γ-aminobutyric acid-, acetylcholine-, and ATP-activated receptors and channels in single pituitary cell types, expanding this picture and revealing surprising differences in their expression between subtypes of secretory cells and between native and immortalized pituitary cells. The main focus of this review is on the electrophysiological and pharmacological properties of these receptors and their roles in calcium signaling and calcium-controlled hormone secretion.
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Affiliation(s)
- Hana Zemková
- Department of Cellular and Molecular Neuroendocrinology, Institute of Physiology, ASCR, Prague, Czech Republic.
| | - Stanko S Stojilkovic
- Sections on Cellular Signaling, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD, USA
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Amyloid-beta neurotoxicity and clearance are both regulated by glial group II metabotropic glutamate receptors. Neuropharmacology 2017; 123:274-286. [DOI: 10.1016/j.neuropharm.2017.05.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 05/05/2017] [Accepted: 05/07/2017] [Indexed: 11/20/2022]
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Abstract
This review compares the biological and physiological function of Sigma receptors [σRs] and their potential therapeutic roles. Sigma receptors are widespread in the central nervous system and across multiple peripheral tissues. σRs consist of sigma receptor one (σ1R) and sigma receptor two (σ2R) and are expressed in numerous regions of the brain. The sigma receptor was originally proposed as a subtype of opioid receptors and was suggested to contribute to the delusions and psychoses induced by benzomorphans such as SKF-10047 and pentazocine. Later studies confirmed that σRs are non-opioid receptors (not an µ opioid receptor) and play a more diverse role in intracellular signaling, apoptosis and metabolic regulation. σ1Rs are intracellular receptors acting as chaperone proteins that modulate Ca2+ signaling through the IP3 receptor. They dynamically translocate inside cells, hence are transmembrane proteins. The σ1R receptor, at the mitochondrial-associated endoplasmic reticulum membrane, is responsible for mitochondrial metabolic regulation and promotes mitochondrial energy depletion and apoptosis. Studies have demonstrated that they play a role as a modulator of ion channels (K+ channels; N-methyl-d-aspartate receptors [NMDAR]; inositol 1,3,5 triphosphate receptors) and regulate lipid transport and metabolism, neuritogenesis, cellular differentiation and myelination in the brain. σ1R modulation of Ca2+ release, modulation of cardiac myocyte contractility and may have links to G-proteins. It has been proposed that σ1Rs are intracellular signal transduction amplifiers. This review of the literature examines the mechanism of action of the σRs, their interaction with neurotransmitters, pharmacology, location and adverse effects mediated through them.
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Affiliation(s)
- Colin G Rousseaux
- a Department of Pathology and Laboratory Medicine , University of Ottawa , Ottawa , ON , Canada and
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Pituitary volume in schizophrenia spectrum disorders. Schizophr Res 2013; 146:301-7. [PMID: 23522905 PMCID: PMC3760333 DOI: 10.1016/j.schres.2013.02.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 02/14/2013] [Accepted: 02/20/2013] [Indexed: 11/22/2022]
Abstract
INTRODUCTION There is converging evidence supporting hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis in schizophrenia spectrum disorders (SSD), such as schizotypal personality disorder (SPD), first-episode schizophrenia (FESZ) and chronic schizophrenia (CHSZ). Such an aberrant HPA activity might have volumetric consequences on the pituitary gland. However, previous magnetic resonance imaging (MRI) studies assessing pituitary volume (PV) in SSD are conflicting. The main objective of this study was to examine further PV in SSD. METHODS PV were manually traced on structural MRIs in 137 subjects, including subjects with SPD (n = 40), FESZ (n = 15), CHSZ (n = 15), and HC (n = 67). We used an ANCOVA to test PV between groups and gender while controlling for inter-subject variability in age, years of education, socioeconomic status, and whole brain volume. RESULTS Overall, women had larger PV than men, and within the male sample all SSD subjects had smaller PV than HC, statistically significant only for the SPD group. In addition, dose of medication, illness duration and age of onset were not associated with PV. CONCLUSION Chronic untreated HPA hyperactivity might account for smaller PV in SPD subjects, whereas the absence of PV changes in FESZ and CHSZ patients might be related to the normalizing effects of antipsychotics on PV. SPD studies offer a way to examine HPA related alterations in SSD without the potential confounds of medication effects.
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Dong L, Quindlen JC, Lipschutz DE, Winkelstein BA. Whiplash-like facet joint loading initiates glutamatergic responses in the DRG and spinal cord associated with behavioral hypersensitivity. Brain Res 2012; 1461:51-63. [PMID: 22578356 DOI: 10.1016/j.brainres.2012.04.026] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 04/05/2012] [Accepted: 04/13/2012] [Indexed: 12/25/2022]
Abstract
The cervical facet joint and its capsule are a common source of neck pain from whiplash. Mechanical hyperalgesia elicited by painful facet joint distraction is associated with spinal neuronal hyperexcitability that can be induced by transmitter/receptor systems that potentiate the synaptic activation of neurons. This study investigated the temporal response of a glutamate receptor and transporters in the dorsal root ganglia (DRG) and spinal cord. Bilateral C6/C7 facet joint distractions were imposed in the rat either to produce behavioral sensitivity or without inducing any sensitivity. Neuronal metabotropic glutamate receptor-5 (mGluR5) and protein kinase C-epsilon (PKCε) expression in the DRG and spinal cord were evaluated on days 1 and 7. Spinal expression of a glutamate transporter, excitatory amino acid carrier 1 (EAAC1), was also quantified at both time points. Painful distraction produced immediate behavioral hypersensitivity that was sustained for 7 days. Increased expression of mGluR5 and PKCε in the DRG was not evident until day 7 and only following painful distraction; this increase was observed in small-diameter neurons. Only painful facet joint distraction produced a significant increase (p<0.001) in neuronal mGluR5 over time, and this increase also was significantly elevated (p≤0.05) over responses in the other groups at day 7. However, there were no differences in spinal PKCε expression on either day or between groups. Spinal EAAC1 expression was significantly increased (p<0.03) only in the nonpainful groups on day 7. Results from this study suggest that spinal glutamatergic plasticity is selectively modulated in association with facet-mediated pain.
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Affiliation(s)
- Ling Dong
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
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Leuze C, Kimura Y, Kershaw J, Shibata S, Saga T, Chuang KH, Shimoyama I, Aoki I. Quantitative measurement of changes in calcium channel activity in vivo utilizing dynamic manganese-enhanced MRI (dMEMRI). Neuroimage 2011; 60:392-9. [PMID: 22227885 DOI: 10.1016/j.neuroimage.2011.12.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Revised: 10/24/2011] [Accepted: 12/15/2011] [Indexed: 10/14/2022] Open
Abstract
The ability of manganese ions (Mn(2+)) to enter cells through calcium ion (Ca(2+)) channels has been used for depolarization dependent brain functional imaging with manganese-enhanced MRI (MEMRI). The purpose of this study was to quantify changes to Mn(2+) uptake in rat brain using a dynamic manganese-enhanced MRI (dMEMRI) scanning protocol with the Patlak and Logan graphical analysis methods. The graphical analysis was based on a three-compartment model describing the tissue and plasma concentration of Mn. Mn(2+) uptake was characterized by the total distribution volume of manganese (Mn) inside tissue (V(T)) and the unidirectional influx constant of Mn(2+) from plasma to tissue (K(i)). The measurements were performed on the anterior (APit) and posterior (PPit) parts of the pituitary gland, a region with an incomplete blood brain barrier. Modulation of Ca(2+) channel activity was performed by administration of the stimulant glutamate and the inhibitor verapamil. It was found that the APit and PPit showed different Mn(2+) uptake characteristics. While the influx of Mn(2+) into the PPit was reversible, Mn(2+) was found to be irreversibly trapped in the APit during the course of the experiment. In the PPit, an increase of Mn(2+) uptake led to an increase in V(T) (from 2.8±0.3 ml/cm(3) to 4.6±1.2 ml/cm(3)) while a decrease of Mn(2+) uptake corresponded to a decrease in V(T) (from 2.8±0.3 ml/cm(3) to 1.4±0.3 ml/cm(3)). In the APit, an increase of Mn(2+) uptake led to an increase in K(i) (from 0.034±0.009 min(-1) to 0.049±0.012 min(-1)) while a decrease of Mn(2+) uptake corresponded to a decrease in K(i) (from 0.034±0.009 min(-1) to 0.019±0.003 min(-1)). This work demonstrates that graphical analysis applied to dMEMRI data can quantitatively measure changes to Mn(2+) uptake following modulation of neural activity.
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Affiliation(s)
- Christoph Leuze
- Molecular Imaging Centre, National Institute of Radiological Sciences, Chiba, Japan
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Durand D, Caruso C, Carniglia L, Lasaga M. Metabotropic glutamate receptor 3 activation prevents nitric oxide-induced death in cultured rat astrocytes. J Neurochem 2010; 112:420-33. [PMID: 20085613 DOI: 10.1111/j.1471-4159.2009.06469.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Altered glial function may contribute to the initiation or progression of neuronal death in neurodegenerative diseases. Thus, modulation of astrocyte death may be essential for preventing pathological processes in the CNS. In recent years, metabotropic glutamate receptor (mGluR) activation has emerged as a key target for neuroprotection. We investigated the effect of subtype 3 mGluR (mGluR3) activation on nitric oxide (NO)-induced astroglial death. A mGluR3 selective agonist, LY379268, reduced inducible NO synthase expression and NO release induced by bacterial lipopolysaccharide and interferon-gamma in cultured rat astrocytes. In turn, a NO donor (diethylenetriamine/NO) induced apoptotic-like death in cultured astrocytes, which showed apoptotic morphology and DNA fragmentation, but no caspase 3 activation. LY379268 prevented astrocyte death induced by NO exposure, which correlates with a reduction in: phosphatidylserine externalization, p53 and Bax activation and mitochondrial permeability. The reported effects of LY379268 were prevented by the mGluR3 antagonist (s)-alpha-ethylglutamic acid. All together, these findings show the protective effect of mGluR3 activation on astroglial death and provide further evidence of a role of these receptors in preventing CNS injury triggered by several inflammatory processes associated with dysregulated NO production.
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Affiliation(s)
- Daniela Durand
- Research Center in Reproduction, School of Medicine, University of Buenos Aires, Buenos Aires, Argentina
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Kocsis ZS, Molnár CS, Watanabe M, Daneels G, Moechars D, Liposits Z, Hrabovszky E. Demonstration of vesicular glutamate transporter-1 in corticotroph cells in the anterior pituitary of the rat. Neurochem Int 2009; 56:479-86. [PMID: 20025917 DOI: 10.1016/j.neuint.2009.12.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2009] [Accepted: 12/11/2009] [Indexed: 11/30/2022]
Abstract
Recent immunohistochemical studies of the rat adenohypophysis identified type-2 vesicular glutamate transporter (VGLUT2), a marker for glutamatergic neuronal phenotype, in high percentages of adenohypophysial gonadotrophs and thyrotrophs. The presence and molecular identity of amino acid neurotransmitters in the remaining hormone producing cell types are unknown. In the present study we addressed the putative synthesis of another glutamatergic marker, VGLUT1 by adenohypophysial cells. Immunohistochemical studies revealed VGLUT1 immunoreactivity in a small subset of polygonal medium-sized cells in the anterior lobe. Western blot analysis revealed a single major 60 kDa protein band in the adenohypophysis. Furthermore, the expression of VGLUT1 mRNA was confirmed by reverse transcription-polymerase chain reaction followed by sequence analysis of the amplicon. In contrast with rats which only showed VGLUT1 signal in the anterior lobe of the pituitary, mice contained high levels of VGLUT1 immunoreactivity in the intermediate, in addition to the anterior lobe. No signal was present in VGLUT1-knockout mice, providing evidence for specificity. In rats, results of colocalization studies with dual-immunofluorescent labeling provided evidence for VGLUT1 immunoreactivity in 45.9% of corticotrophs and 7.7% of luteinizing hormone beta-immunopositive gonadotrophs. Cells of the other peptide hormone phenotypes were devoid of VGLUT1 signal. A few cells in the adenohypophysis expressed both VGLUT1 and VGLUT2 immunoreactivities. The presence of the glutamate markers VGLUT1 and VGLUT2 in distinct populations of peptide hormone-secreting hypophysial cells highly indicates the involvement of endogenous glutamate release in autocrine/paracrine regulatory mechanisms. The biological function of adenohypophysial glutamate will require clarification.
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Affiliation(s)
- Zsuzsa S Kocsis
- Laboratory of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest 1083, Hungary
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Daily pattern of pituitary glutamine, glutamate, and aspartate content disrupted by cadmium exposure. Amino Acids 2009; 38:1165-72. [PMID: 19636671 DOI: 10.1007/s00726-009-0327-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Accepted: 07/13/2009] [Indexed: 10/20/2022]
Abstract
Cadmium is a neurotoxic heavy metal and is considered endocrine disruptor. In this work, we investigate the effects of cadmium on the 24 h changes of aspartate, glutamate, and glutamine content in the pituitary. Adult male Sprague-Dawley rats were treated with 25 or 50 mg/l of cadmium chloride (CdCl(2)) in the drinking water for 30 days. Metal exposure with the lowest dose induced the disappearance of the nocturnal peak of anterior pituitary amino acid content, and the appearance of a peak of glutamine concentration during the resting phase of the photoperiod. After exposure to 50 mg/l of CdCl(2), the peaks of anterior pituitary amino acid content at 12:00 and 00:00 h disappeared, and two minimal values at these same hours and a peak at 08:00 h appeared. In the posterior pituitary, cadmium treatment with the lowest dose induced the appearance of a peak of aspartate and glutamate concentration at 12:00 h, and the disappearance of the peak of glutamine content at 16:00 h. After exposure to 50 mg/l of CdCl(2) aspartate and glutamate daily pattern presented two maximal values between 00:00 and 04:00 h, and the metal abolished glutamine daily pattern. These results suggest that cadmium disrupted aspartate, glutamate, and glutamine daily pattern in the pituitary.
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Seeman P, Guan HC. Phencyclidine and glutamate agonist LY379268 stimulate dopamine D2High receptors: D2 basis for schizophrenia. Synapse 2009; 62:819-28. [PMID: 18720422 DOI: 10.1002/syn.20561] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
It has previously been reported that the glutamate ionotropic antagonist phencyclidine directly inhibits the release of prolactin in anterior pituitary cells in culture, suggesting that phencyclidine has a dopamine (DA)-like action on prolactin-releasing cells. It has also been reported that the glutamate metabotropic agonist LY379268 can stimulate the incorporation of [35S]GTP-gamma-S into DA D2Long receptors. The present study was done to examine whether such glutamatergic drugs had similar actions on the DA D2Short receptor. The present results show that phencyclidine, ketamine, and LY379268 also stimulated the incorporation of [35S]GTP-gamma-S into D2Short receptors. The proportion of D2Long and D2Short receptors existing in the high-affinity state were both markedly reduced by NaCl. While phencyclidine and LY379268 each stimulated the incorporation of GTP-gamma-S into D2Long and D2Short receptors, this stimulation was reduced by NaCl, with D2Short being much more sensitive than D2Long to the inhibition by NaCl. The binding of phencyclidine and LY379268 to D2High receptors in vivo was directly confirmed by the i.v. injection of phencyclidine and LY379268 in which 50% inhibited the binding of [3H]PHNO to the striatum ex vivo at 0.25 and 1.5 mg/kg, respectively. The results confirm that glutamate agonists and antagonists have a significant affinity for DA D2High receptors. The psychotogenic action of phencyclidine may stem from a combination or synergistic action of glutamate receptor antagonism and DA D2 agonism. In addition, the antipsychotic clinical action of LY379268 congeners such as LY404039 may be related to a combined or synergistic action of glutamate receptor stimulation together with a partial DA agonist action that reduces endogenous DA neurotransmission.
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Affiliation(s)
- Philip Seeman
- Department of Pharmacology, University of Toronto, Toronto, Ontario, Canada.
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15
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Seeman P, Battaglia G, Corti C, Corsi M, Bruno V. Glutamate receptor mGlu2 and mGlu3 knockout striata are dopamine supersensitive, with elevated D2(High) receptors and marked supersensitivity to the dopamine agonist (+)PHNO. Synapse 2009; 63:247-51. [PMID: 19084908 DOI: 10.1002/syn.20607] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The finding that the mGlu2/3 metabotropic glutamate receptor agonist, LY404039, improves clinical symptoms in schizophrenia warrants a search for a possible interaction between mGlu2/3 receptors and dopamine D2 receptors. Here, this topic is examined in striatal tissue of mice lacking either mGlu2 or mGlu3 receptor. Such mice are known to be behaviorally supersensitive to dopamine receptor agonists. Therefore, to determine the basis of this dopamine supersensitivity, the proportion of dopamine D2(High) receptors was measured in the striata of mGlu2 and mGlu3 receptor knockout mice. The proportion of D2(High) receptors was found to be elevated by 220% in the striata of both knockouts. To measure the functional dopamine supersensitivity, the D2 agonist (+)PHNO was used to stimulate the incorporation of GTP-gamma-S in the striatal homogenates in the presence of drugs that blocked the dopamine D1, D3, and D5 receptors. Compared with control striata, the mGlu2 receptor knockout tissues were 67-fold more sensitive to (+)PHNO, while the mGlu3 receptor knockout tissues were 17-fold more sensitive. These data suggest that group II mGlu receptors-mGlu2 receptors in particular-may normally regulate D2 receptors by reducing the proportion of high-affinity D2 receptors in membranes. Such regulation may contribute to the antipsychotic action of mGlu2/3 receptor agonists.
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Affiliation(s)
- Philip Seeman
- Department of Pharmacology, Medical Science Building, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada.
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16
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Durand D, Pampillo M, Caruso C, Lasaga M. Role of metabotropic glutamate receptors in the control of neuroendocrine function. Neuropharmacology 2008; 55:577-83. [PMID: 18616955 DOI: 10.1016/j.neuropharm.2008.06.022] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2008] [Revised: 05/23/2008] [Accepted: 06/12/2008] [Indexed: 11/25/2022]
Abstract
Glutamate exerts its effects through binding and activation of two classes of specific receptors: ionotropic (iGluRs) and metabotropic (mGluRs). Group I mGluR includes mGluR1 and mGluR5 subtypes, group II includes mGluR2 and mGluR3 subtypes and group III includes the subtypes mGluR 4, 6, 7 and 8. Glutamate and its receptors are found in all key hypothalamic areas critically involved in reproduction and neuroendocrine function. To date, considerable data support an important role for iGluRs in the control of neuroendocrine function; however, the role of mGluRs as regulators of hypothalamic-pituitary function has not been clearly elucidated. mGluRs could be exerting a fine tune on the release of hypothalamic factors that regulate hormone release such as Substance P, GABA, alpha-MSH and CRH. Group II mGluR exert a direct inhibitory effect on anterior pituitary prolactin and GH secretion. Moreover, some group II mGluR agonists, like LY 354,740 and LY 379,268, can modulate PRL secretion from the anterior pituitary through their actions as dopamine receptor agonists. Evidence suggests a role for group III mGluR subtypes in stress-related behavioral disorders. Several reports indicate that selective ligands for mGluR subtypes have potential for the treatment of a wide variety of neurological and psychiatric disorders, including depression, anxiety disorders, schizophrenia, epilepsy and Alzheimer's disease among others. Since converging lines of evidence suggest a role for mGluRs subtypes in neuroendocrine regulation of hormone secretion, mGluRs neuroendocrine actions must be taken in consideration to insure proper treatment of these diseases. Moreover, discovery of selective agonists provides an opportunity to investigate the physiological role of mGluR subtypes and to directly test the neuroendocrine actions of mGluRs. Finally, mGluRs selective agonists may have an impact in the treatment of conditions involving chronic stress, such as depression and anxiety disorders, since they regulate neuroendocrine stress circuits involving the HPA axis and stress-sensitive hormones such as oxytocin and prolactin. This review aims to provide a survey of our current understanding of the effects of mGluR activation on neuroendocrine function.
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Affiliation(s)
- Daniela Durand
- Research Center in Reproduction, School of Medicine, University of Buenos Aires, Paraguay 2155, Piso 10, 1121 Buenos Aires, Argentina
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17
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Abstract
L-glutamate, the main excitatory neurotransmitter, influences virtually all neurones of the neuroendocrine hypothalamus via synaptic mechanisms. Vesicular glutamate transporters (VGLUT1-3), which selectively accumulate L-glutamate into synaptic vesicles, provide markers with which to visualise glutamatergic neurones in histological preparations; excitatory neurones in the endocrine hypothalamus synthesise the VGLUT2 isoform. Results of recent dual-label in situ hybridisation studies indicate that glutamatergic neurones in the preoptic area and the hypothalamic paraventricular, supraoptic and periventricular nuclei include parvocellular and magnocellular neurosecretory neurones which secrete peptide neurohormones into the bloodstream to regulate endocrine functions. Neurosecretory terminals of GnRH, TRH, CRF-, somatostatin-, oxytocin- and vasopressin-secreting neurones contain VGLUT2 immunoreactivity, suggesting the co-release of glutamate with hypophysiotrophic peptides. The presence of VGLUT2 also indicates glutamate secretion from non-neuronal endocrine cells, including gonadotrophs and thyrotrophs of the anterior pituitary. Results of in vitro studies show that ionotropic glutamate receptor analogues can elicit hormone secretion at neuroendocrine/endocrine release sites. Structural constituents of the median eminence, adenohypophysis and neurohypophysis contain elements of glutamatergic transmission, including glutamate receptors and enzymes of the glutamate/glutamine cycle. The synthesis of VGLUT2 exhibits robust up-regulation in response to certain endocrine challenges, indicating that altered glutamatergic signalling may represent an important adaptive mechanism. This review article discusses the newly emerged non-synaptic role of glutamate in neuroendocrine and endocrine communication.
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Affiliation(s)
- E Hrabovszky
- Laboratory of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
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Seeman P, Caruso C, Lasaga M. Dopamine partial agonist actions of the glutamate receptor agonists LY 354,740 and LY 379,268. Synapse 2008; 62:154-8. [PMID: 18000815 DOI: 10.1002/syn.20482] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Because glutamate compounds alter the release of dopamine and prolactin, the present study examined whether group II metabotropic receptor agonists, LY 354,740 and LY 379,268, had any direct in vitro action on dopamine D2 receptors on rat striatal tissue, cloned D2Long receptors, and prolactin release from anterior pituitary cells. In competition versus the D2-specific ligand [(3)H]domperidone, LY 354,740 had a dissociation constant of 24 nM at D2(High) (the functional high-affinity state of dopamine D2 receptors), while the value for LY 379,268 was 21 nM. LY 354,740 also stimulated by 50% the incorporation of [(35)S]-GTP-gamma-S at a concentration of 120 nM, but its maximal stimulation was only 22% of the maximum elicited by dopamine. LY 379,268 stimulated by 50% the incorporation of [(35)S]-GTP-gamma-S at 280 nM, but its maximal stimulation was also only 22% of the maximum elicited by dopamine. However, both LY 354,740 and LY 379,268 potently inhibited the dopamine-induced incorporation of [(35)S]-GTP-gamma-S with inhibitory Ki values of 43 nM and 30 nM, respectively. The release of prolactin from rat isolated anterior pituitary cells in culture was 50% inhibited by 20 nM LY 379,268 and by 100 nM LY 354,740. These Ki values are similar to those known for the mGluR II receptor, suggesting that these compounds may have both glutamate and dopamine actions in vivo. The dopamine agonist and antagonist actions of these compounds indicate that these drugs have properties of a dopamine partial agonist, and may, therefore, have antipsychotic action.
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Affiliation(s)
- Philip Seeman
- Department of Pharmacology, Medical Science Building 4344, University of Toronto, Toronto, Ontario, Canada M5S 1A8.
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19
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Rousseaux CG. A Review of Glutamate Receptors II: Pathophysiology and Pathology. J Toxicol Pathol 2008. [DOI: 10.1293/tox.21.133] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Colin G. Rousseaux
- Department of Pathology and Laboratory Medicine, Faculty of Medicine, University of Ottawa
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Caruso C, Durand D, Schiöth HB, Rey R, Seilicovich A, Lasaga M. Activation of melanocortin 4 receptors reduces the inflammatory response and prevents apoptosis induced by lipopolysaccharide and interferon-gamma in astrocytes. Endocrinology 2007; 148:4918-26. [PMID: 17595227 DOI: 10.1210/en.2007-0366] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Alpha-MSH exerts an immunomodulatory action in the brain and may play a neuroprotective role acting through melanocortin 4 receptors (MC4Rs). In the present study, we show that MC4Rs are constitutively expressed in astrocytes as determined by immunocytochemistry, RT-PCR, and Western blot analysis. alpha-MSH (5 microm) reduced the nitric oxide production and the expression of inducible nitric oxide synthase (iNOS) induced by bacterial lipopolysaccharide (LPS, 1 microg/ml) plus interferon-gamma (IFN-gamma, 50 ng/ml) in cultured astrocytes after 24 h. alpha-MSH also attenuated the stimulatory effect of LPS/IFN-gamma on prostaglandin E(2) release and cyclooxygenase-2 (COX-2) expression. Treatment with HS024, a selective MC4R antagonist, blocked the antiinflammatory effects of alpha-MSH, suggesting a MC4R-mediated mechanism in the action of this melanocortin. In astrocytes, LPS/IFN-gamma treatment reduced cell viability, increased the number of terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling-positive cells and activated caspase-3. alpha-MSH prevented these apoptotic events, and this cytoprotective effect was abolished by HS024. LPS/IFN-gamma decreased Bcl-2, whereas it increased Bax protein expression in astrocytes, thus increasing the Bax/Bcl-2 ratio. Alpha-MSH produced a shift in Bax/Bcl-2 ratio toward astrocyte survival because it increased Bcl-2 expression and also prevented the effect of LPS/IFN-gamma on Bax and Bcl-2 expression. In summary, these findings suggest that alpha-MSH, through MC4R activation, attenuates LPS/IFN-gamma-induced inflammation by decreasing iNOS and COX-2 expression and prevents LPS/IFN-gamma-induced apoptosis of astrocytes by modulating the expression of proteins of the Bcl-2 family.
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Affiliation(s)
- Carla Caruso
- Centro de Investigaciones en Reproducción, School of Medicine, University of Buenos Aires, Buenos Aires 1121ABG, Argentina
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Delgado-Rubín de Célix A, Chowen JA, Argente J, Frago LM. Growth hormone releasing peptide-6 acts as a survival factor in glutamate-induced excitotoxicity. J Neurochem 2006; 99:839-49. [PMID: 17076656 DOI: 10.1111/j.1471-4159.2006.04122.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Chronic systemic treatment given to adult male rats with growth hormone releasing peptide-6, an agonist of the ghrelin receptor, increases insulin-like growth factor I levels in various brain regions, including the hypothalamus and cerebellum. Furthermore, intracellular signalling cascades normally associated with anti-apoptotic actions are activated in the same areas and are coincident with decreased basal cell death. Because abnormally high concentrations of glutamate can lead to overexcitation of neurones leading to cell damage and/or death, we investigated whether administration of growth hormone releasing peptide-6 attenuates monosodium glutamate-induced apoptosis in the rat hypothalamus and cerebellum. Glutamate increased activation of caspase 9 followed by cleavage of caspase 7, which in turn fragmented poly(ADP-ribose) polymerase, terminating in cell death in both the hypothalamus and cerebellum. Growth hormone releasing peptide-6 reversed glutamate-induced cell death by decreasing activation of caspases 9 and 7 and poly(ADP-ribose) polymerase fragmentation. These results provide a better understanding of the neuroprotective role of growth hormone secretagogues and the mechanisms involved.
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Affiliation(s)
- Arancha Delgado-Rubín de Célix
- Universidad Autónoma de Madrid. Departament of Pediatrics. Hospital Infantil Universitario Niño Jesús, Departament of Endocrinology, Madrid, Spain
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22
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Debeljuk L, Lasaga M. Tachykinins and the control of prolactin secretion. Peptides 2006; 27:3007-19. [PMID: 16930771 DOI: 10.1016/j.peptides.2006.07.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2006] [Revised: 07/14/2006] [Accepted: 07/17/2006] [Indexed: 11/28/2022]
Abstract
Tachykinins are present in the pituitary gland and in brain areas involved in the control of the secretion of pituitary hormones. Tachykinins have been demonstrated to stimulate prolactin release acting directly on the anterior pituitary gland. These peptides have also been revealed to be able to act at the hypothalamic level, interacting with neurotransmitters and neuropeptides that have the potential to affect prolactin secretion. Tachykinins seem to act by stimulating or inhibiting the release of the factors that affect prolactin secretion. Among them, tachykinins have been demonstrated to stimulate oxytocin and vasopressin release, which in turn results in prolactin release. Tachykinins also potentiated the response to vasoactive intestinal peptide (VIP) and reinforced the action of glutamate, which in turn result in prolactin release. They have also been shown to interact with serotonin, a neurotransmitter involved in the control of prolactin secretion. In addition, tachykinins have been shown to inhibit GABA release, a neurotransmitter with prolactin-release inhibiting effect. This inhibition may result in an increased prolactin secretion by removal of the GABA inhibition. On the other hand, tachykinins have also been shown to stimulate dopamine release by the hypothalamus, an action that results in an inhibition of prolactin release. Dopamine is a well known inhibitor of prolactin secretion. In conclusion, although tachykinins have been shown to have a predominantly stimulatory effect on prolactin secretion, especially at the pituitary level, under some circumstances they may also exert an inhibitory influence on prolactin release, by stimulating dopamine release at the hypothalamic level.
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Affiliation(s)
- Luciano Debeljuk
- School of Allied Health (Anatomy and Physiology), College of Applied Sciences and Arts, Southern Illinois University, Carbondale, IL 62901, USA.
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23
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Hrabovszky E, Kalló I, Turi GF, May K, Wittmann G, Fekete C, Liposits Z. Expression of vesicular glutamate transporter-2 in gonadotrope and thyrotrope cells of the rat pituitary. Regulation by estrogen and thyroid hormone status. Endocrinology 2006; 147:3818-25. [PMID: 16675529 DOI: 10.1210/en.2005-1229] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Immunocytochemical studies of the rat adenohypophysis identified a cell population that exhibits immunoreactivity for type-2 vesicular glutamate transporter (VGLUT2), a marker for glutamatergic neuronal phenotype. The in situ hybridization detection of VGLUT2 mRNA expression in adenohypophysial cells verified that VGLUT2 immunoreactivity is due to local synthesis of authentic VGLUT2. Dual-immunofluorescent studies of the hypophyses from male rats showed the presence of VGLUT2 in high percentages of LH (93.3 +/- 1.3%)-, FSH (44.7 +/- 3.9%)-, and TSH (70.0 +/- 5.6%)-immunoreactive cells and its much lower incidence in cells of the prolactin, GH, and ACTH phenotypes. Quantitative in situ hybridization studies have established that the administration of a single dose of 17-beta-estradiol (20 microg/kg; sc) to ovariectomized rats significantly elevated VGLUT2 mRNA in the adenohypophysis 16 h postinjection. Thyroid hormone dependence of VGLUT2 expression was addressed by the comparison of hybridization signals in animal models of hypo- and hyperthyroidism to those in euthyroid controls. Although hyperthyroidism had no effect on VGLUT2 mRNA, hypothyroidism increased adenohypophysial VGLUT2 mRNA levels. This coincided with a decreased ratio of VGLUT2-immunoreactive TSH cells, regarded as a sign of enhanced secretion. The presence of the glutamate marker VGLUT2 in gonadotrope and thyrotrope cells, and its up-regulation by estrogen or hypothyroidism, address the possibility that endocrine cells of the adenohypophysis may cosecrete glutamate with peptide hormones in an estrogen- and thyroid status-regulated manner. The exact roles of endogenous glutamate observed primarily in gonadotropes and thyrotropes, including its putative involvement in autocrine/paracrine regulatory mechanisms, will require clarification.
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Affiliation(s)
- Erik Hrabovszky
- Laboratory of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Szigony u. 43, Budapest, 1083 Hungary.
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24
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Glucocorticoid-Inducible Glutamine Synthetase in GH Cells of Chick Embryos, Gallus domesticus: Ontogeny of Glutamine Synthetase, GH, and Pit-1 Protein in the Pituitary Gland. J Poult Sci 2006. [DOI: 10.2141/jpsa.43.266] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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25
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Maiese K, Chong ZZ, Li F. Driving cellular plasticity and survival through the signal transduction pathways of metabotropic glutamate receptors. Curr Neurovasc Res 2005; 2:425-46. [PMID: 16375723 PMCID: PMC2258008 DOI: 10.2174/156720205774962692] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Metabotropic glutamate receptors (mGluRs) share a common molecular morphology with other G protein-linked receptors, but there expression throughout the mammalian nervous system places these receptors as essential mediators not only for the initial development of an organism, but also for the vital determination of a cell's fate during many disorders in the nervous system that include amyotrophic lateral sclerosis, Parkinson's disease, Alzheimer's disease, Huntington's disease, Multiple Sclerosis, epilepsy, trauma, and stroke. Given the ubiquitous distribution of these receptors, the mGluR system impacts upon neuronal, vascular, and glial cell function and is activated by a wide variety of stimuli that includes neurotransmitters, peptides, hormones, growth factors, ions, lipids, and light. Employing signal transduction pathways that can modulate both excitatory and inhibitory responses, the mGluR system drives a spectrum of cellular pathways that involve protein kinases, endonucleases, cellular acidity, energy metabolism, mitochondrial membrane potential, caspases, and specific mitogen-activated protein kinases. Ultimately these pathways can converge to regulate genomic DNA degradation, membrane phosphatidylserine (PS) residue exposure, and inflammatory microglial activation. As we continue to push the envelope for our understanding of this complex and critical family of metabotropic receptors, we should be able to reap enormous benefits for both clinical disease as well as our understanding of basic biology in the nervous system.
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Affiliation(s)
- Kenneth Maiese
- Division of Cellular and Molecular Cerebral Ischemia, Department of Neurology, 8C-1 UHC, Wayne State University School of Medicine, 4201 St. Antoine, Detroit, MI 48201, USA.
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Hrabovszky E, Turi GF, Liposits Z. Presence of vesicular glutamate transporter-2 in hypophysiotropic somatostatin but not growth hormone-releasing hormone neurons of the male rat. Eur J Neurosci 2005; 21:2120-6. [PMID: 15869508 DOI: 10.1111/j.1460-9568.2005.04076.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Recent evidence indicates that hypophysiotropic gonadotropin-releasing hormone (GnRH), corticotropin-releasing hormone (CRH) and thyrotropin-releasing hormone (TRH) neurons of the adult male rat express mRNA and immunoreactivity for type-2 vesicular glutamate transporter (VGLUT2), a marker for glutamatergic neuronal phenotype. In the present study, we investigated the issue of whether these glutamatergic features are shared by growth hormone-releasing hormone (GHRH) neurons of the hypothalamic arcuate nucleus (ARH) and somatostatin (SS) neurons of the anterior periventricular nucleus (PVa), the two parvicellular neurosecretory systems that regulate anterior pituitary somatotrophs. Dual-label in situ hybridization studies revealed relatively few cells that expressed VGLUT2 mRNA in the ARH; the GHRH neurons were devoid of VGLUT2 hybridization signal. In contrast, VGLUT2 mRNA was expressed abundantly in the PVa; virtually all (97.5 +/- 0.4%) SS neurons showed labelling for VGLUT2 mRNA. In accordance with these hybridization results, dual-label immunofluorescent studies followed by confocal laser microscopic analysis of the median eminence established the absence of VGLUT2 immunoreactivity in GHRH terminals and its presence in many neurosecretory SS terminals. The GHRH terminals, in turn, were immunoreactive for the vesicular gamma-aminobutyric acid (GABA) transporter, used in these studies as a marker for GABA-ergic neuronal phenotype. Together, these results suggest the paradoxic cosecretion of the excitatory amino acid neurotransmitter glutamate with the inhibitory peptide SS and the cosecretion of the inhibitory amino acid neurotransmitter GABA with the stimulatory peptide GHRH. The mechanisms of action of intrinsic amino acids in hypophysiotropic neurosecretory systems require clarification.
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Affiliation(s)
- Erik Hrabovszky
- Laboratory of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Szigony u. 43., Budapest, 1083 Hungary.
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Deshpande M, Zheng J, Borgmann K, Persidsky R, Wu L, Schellpeper C, Ghorpade A. Role of activated astrocytes in neuronal damage: potential links to HIV-1-associated dementia. Neurotox Res 2005; 7:183-92. [PMID: 15897153 DOI: 10.1007/bf03036448] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
HIV-1-associated dementia (HAD) is an important complication of HIV-1 infection. Reactive astrogliosis is a key pathological feature in HAD brains and in other central nervous system (CNS) diseases. Activated astroglia may play a critical role in CNS inflammatory diseases such as HAD. In order to test the hypothesis that activated astrocytes cause neuronal injury, we stimulated primary human fetal astrocytes with HAD-relevant pro-inflammatory cytokine IL-1beta. IL-1beta-activated astrocytes induced apoptosis and significant changes in metabolic activity in primary human neurons. An FITC-conjugated pan-caspase inhibitor peptide FITC-VAD-FMK was used for confirming caspase activation in neurons. IL-1beta activation enhanced the expression of death protein FasL in astrocytes, suggesting that FasL is one of the potential factors responsible for neurotoxicity observed in HAD and other CNS diseases involving glial inflammation. Our data presented here add to the developing picture of role of activated glia in HAD pathogenesis.
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Affiliation(s)
- M Deshpande
- Laboratories of Cellular Neuroimmunology and Neurotoxicology, Center for Neurovirology and Neurodegenerative Disorders, Department of Pharmacology, University of Nebraska Medical Center, Omaha, Nebraska 68198-5215, USA
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Abstract
Although the psychotomimetic action of phencyclidine is often used to model a hypoglutamate theory of psychosis or schizophrenia, work also exists showing that phencyclidine has a significant affinity for the dopamine D2 receptor. The present study was done to determine whether phencyclidine has a direct functional dopamine-like action on cells. The effect of phencyclidine was tested on the release of prolactin from rat cultured anterior pituitary cells. It was found that the release of prolactin was 50% inhibited by 4 nM phencyclidine. This strong dopamine-like agonist action at the functional high-affinity state of the dopamine D2 receptor by the phencyclidine psychotomimetic is consistent with the dopamine hypothesis of psychosis.
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Affiliation(s)
- Philip Seeman
- Departments of Pharmacology and Psychiatry, University of Toronto, Medical Science Building, Ontario, Canada.
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