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Merkler DJ, Hawley AJ, Eipper BA, Mains RE. Peptidylglycine α-amidating monooxygenase as a therapeutic target or biomarker for human diseases. Br J Pharmacol 2022; 179:3306-3324. [PMID: 35124797 PMCID: PMC9177522 DOI: 10.1111/bph.15815] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 01/10/2022] [Accepted: 01/12/2022] [Indexed: 01/20/2024] Open
Abstract
Peptides play a key role in controlling many physiological and neurobiological pathways. Many bioactive peptides require a C-terminal α-amide for full activity. The bifunctional enzyme catalysing α-amidation, peptidylglycine α-amidating monooxygenase (PAM), is the sole enzyme responsible for amidated peptide biosynthesis, from Chlamydomonas reinhardtii to Homo sapiens. Many neuronal and endocrine functions are dependent upon amidated peptides; additional amidated peptides are growth promoters in tumours. The amidation reaction occurs in two steps, glycine α-hydroxylation followed by dealkylation to generate the α-amide product. Currently, most potentially useful inhibitors target the first reaction, which is rate-limiting. PAM is a membrane-bound enzyme that visits the cell surface during peptide secretion. PAM is then used again in the biosynthetic pathway, meaning that cell-impermeable inhibitors or inactivators could have therapeutic value for the treatment of cancer or psychiatric abnormalities. To date, inhibitor design has not fully exploited the structures and mechanistic details of PAM.
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Affiliation(s)
- David J Merkler
- Department of Chemistry, University of South Florida, 4202 E. Fowler Ave., Tampa, FL 33620, USA
| | - Aidan J Hawley
- Department of Chemistry, University of South Florida, 4202 E. Fowler Ave., Tampa, FL 33620, USA
| | - Betty A Eipper
- Department of Molecular Biology & Biophysics, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT, 06030 USA
- Department of Neuroscience, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT, 06030 USA
| | - Richard E Mains
- Department of Neuroscience, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT, 06030 USA
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2
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Wen MH, Xie X, Huang PS, Yang K, Chen TY. Crossroads between membrane trafficking machinery and copper homeostasis in the nerve system. Open Biol 2021; 11:210128. [PMID: 34847776 PMCID: PMC8633785 DOI: 10.1098/rsob.210128] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Imbalanced copper homeostasis and perturbation of membrane trafficking are two common symptoms that have been associated with the pathogenesis of neurodegenerative and neurodevelopmental diseases. Accumulating evidence from biophysical, cellular and in vivo studies suggest that membrane trafficking orchestrates both copper homeostasis and neural functions-however, a systematic review of how copper homeostasis and membrane trafficking interplays in neurons remains lacking. Here, we summarize current knowledge of the general trafficking itineraries for copper transporters and highlight several critical membrane trafficking regulators in maintaining copper homeostasis. We discuss how membrane trafficking regulators may alter copper transporter distribution in different membrane compartments to regulate intracellular copper homeostasis. Using Parkinson's disease and MEDNIK as examples, we further elaborate how misregulated trafficking regulators may interplay parallelly or synergistically with copper dyshomeostasis in devastating pathogenesis in neurodegenerative diseases. Finally, we explore multiple unsolved questions and highlight the existing challenges to understand how copper homeostasis is modulated through membrane trafficking.
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Affiliation(s)
- Meng-Hsuan Wen
- Department of Chemistry, University of Houston, Houston, TX 77204, USA
| | - Xihong Xie
- Department of Chemistry, University of Houston, Houston, TX 77204, USA
| | - Pei-San Huang
- Department of Chemistry, University of Houston, Houston, TX 77204, USA
| | - Karen Yang
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Tai-Yen Chen
- Department of Chemistry, University of Houston, Houston, TX 77204, USA
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3
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Powers KG, Ma XM, Eipper BA, Mains RE. Cell-type specific knockout of peptidylglycine α-amidating monooxygenase reveals specific behavioral roles in excitatory forebrain neurons and cardiomyocytes. GENES BRAIN AND BEHAVIOR 2020; 20:e12699. [PMID: 32902163 DOI: 10.1111/gbb.12699] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 09/05/2020] [Accepted: 09/07/2020] [Indexed: 01/11/2023]
Abstract
Neuropeptides and peptide hormones play a crucial role in integrating the many factors that affect physiologic and cognitive processes. The potency of many of these peptides requires an amidated amino acid at the C-terminus; a single enzyme, peptidylglycine α-amidating monooxygenase (PAM), catalyzes this modification. Anxiety-like behavior is known to be altered in mice with a single functional Pam allele (Pam+/- ) and in mice unable to express Pam in excitatory forebrain neurons (PamEmx1-cKO/cKO ) or in cardiomyocytes (PamMyh6-cKO/cKO ). Examination of PAM-positive and glutamic acid decarboxylase 67 (GAD)-positive cells in the amygdala of PamEmx1-cKO/cKO mice demonstrated the absence of PAM in pyramidal neurons and its continued presence in GAD-positive interneurons, suggestive of altered excitatory/inhibitory balance. Additional behavioral tests were used to search for functional alterations in these cell-type specific knockout mice. PamEmx1-cKO/cKO mice exhibited a less focused search pattern for the Barnes Maze escape hole than control or PamMyh6-cKO/cKO mice. While wildtype mice favor interacting with novel objects as opposed to familiar objects, both PamEmx1-cKO/cKO and PamMyh6-cKO/cKO mice exhibited significantly less interest in the novel object. Since PAM levels in the central nervous system of PamMyh6-cKO/cKO mice are unaltered, the behavioral effect observed in these mice may reflect their inability to produce atrial granules and the resulting reduction in serum levels of atrial natriuretic peptide. In the sociability test, male mice of all three genotypes spent more time with same-sex stranger mice; while control females showed no preference for stranger mice, female PamEmx1-cKO/cKO mice showed preference for same-sex stranger mice in all trials.
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Affiliation(s)
- Kathryn G Powers
- Department of Neuroscience, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Xin-Ming Ma
- Department of Neuroscience, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Betty A Eipper
- Department of Neuroscience, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Richard E Mains
- Department of Neuroscience, University of Connecticut Health Center, Farmington, Connecticut, USA
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4
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Chen YC, Mains RE, Eipper BA, Hoffman BG, Czyzyk TA, Pintar JE, Verchere CB. PAM haploinsufficiency does not accelerate the development of diet- and human IAPP-induced diabetes in mice. Diabetologia 2020; 63:561-576. [PMID: 31984442 PMCID: PMC7864590 DOI: 10.1007/s00125-019-05060-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Accepted: 10/28/2019] [Indexed: 12/17/2022]
Abstract
AIMS/HYPOTHESIS Peptide hormones are first synthesised as larger, inactive precursors that are converted to their active forms by endopeptidase cleavage and post-translational modifications, such as amidation. Recent, large-scale genome-wide studies have suggested that two coding variants of the amidating enzyme, peptidylglycine α-amidating monooxygenase (PAM), are associated with impaired insulin secretion and increased type 2 diabetes risk. We aimed to elucidate the role of PAM in modulating beta cell peptide amidation, beta cell function and the development of diabetes. METHODS PAM transcript and protein levels were analysed in mouse islets following induction of endoplasmic reticulum (ER) or cytokine stress, and PAM expression patterns were examined in human islets. To study whether haploinsufficiency of PAM accelerates the development of diabetes, Pam+/- and Pam+/+ mice were fed a low-fat diet (LFD) or high-fat diet (HFD) and glucose homeostasis was assessed. Since aggregates of the PAM substrate human islet amyloid polypeptide (hIAPP) lead to islet inflammation and beta cell failure, we also investigated whether PAM haploinsufficiency accelerated hIAPP-induced diabetes and islet amyloid formation in Pam+/- and Pam+/+ mice with beta cell expression of hIAPP. RESULTS Immunostaining revealed high expression of PAM in alpha, beta and delta cells in human pancreatic islets. Pam mRNA and PAM protein expression were reduced in mouse islets following administration of an HFD, and in isolated islets following induction of ER stress with thapsigargin, or cytokine stress with IL-1β, IFN-γ and TFN-α. Despite Pam+/- only having 50% PAM expression and enzyme activity as compared with Pam+/+ mice, glucose tolerance and body mass composition were comparable in the two models. After 24 weeks of HFD, both Pam+/- and Pam+/+ mice had insulin resistance and impaired glucose tolerance, but no differences in glucose tolerance, insulin sensitivity or plasma insulin levels were observed in PAM haploinsufficient mice. Islet amyloid formation and beta cell function were also similar in Pam+/- and Pam+/+ mice with beta cell expression of hIAPP. CONCLUSIONS/INTERPRETATION Haploinsufficiency of PAM in mice does not accelerate the development of diet-induced obesity or hIAPP transgene-induced diabetes.
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MESH Headings
- Amidine-Lyases/genetics
- Amidine-Lyases/physiology
- Animals
- Cells, Cultured
- Diabetes Mellitus, Experimental/genetics
- Diabetes Mellitus, Experimental/pathology
- Diabetes Mellitus, Type 2/genetics
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/pathology
- Disease Progression
- Epistasis, Genetic/physiology
- Female
- Genetic Predisposition to Disease
- Haploinsufficiency
- Humans
- Insulin-Secreting Cells/metabolism
- Insulin-Secreting Cells/pathology
- Islet Amyloid Polypeptide/genetics
- Islet Amyloid Polypeptide/physiology
- Islets of Langerhans/metabolism
- Islets of Langerhans/pathology
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Mixed Function Oxygenases/genetics
- Mixed Function Oxygenases/physiology
- Rats
- Rats, Inbred Lew
- Risk Factors
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Affiliation(s)
- Yi-Chun Chen
- Department of Surgery, University of British Columbia and BC Children's Hospital Research Institute, 950 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada
| | - Richard E Mains
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT, USA
| | - Betty A Eipper
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT, USA
| | - Brad G Hoffman
- Department of Surgery, University of British Columbia and BC Children's Hospital Research Institute, 950 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada
| | - Traci A Czyzyk
- Division of Cardio-renal and Metabolic Disease, Merck Research Laboratories, San Francisco, CA, USA
| | - John E Pintar
- Department of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, USA
| | - C Bruce Verchere
- Department of Surgery, University of British Columbia and BC Children's Hospital Research Institute, 950 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada.
- Department of Pathology and Laboratory Medicine, University of British Columbia and BC Children's Hospital Research Institute, Vancouver, BC, Canada.
- Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, BC, Canada.
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5
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Perez-Siles G, Cutrupi A, Ellis M, Kuriakose J, La Fontaine S, Mao D, Uesugi M, Takata RI, Speck-Martins CE, Nicholson G, Kennerson ML. Modelling the pathogenesis of X-linked distal hereditary motor neuropathy using patient-derived iPSCs. Dis Model Mech 2020; 13:13/2/dmm041541. [PMID: 31969342 PMCID: PMC6994953 DOI: 10.1242/dmm.041541] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 11/26/2019] [Indexed: 11/20/2022] Open
Abstract
ATP7A encodes a copper-transporting P-type ATPase and is one of 23 genes in which mutations produce distal hereditary motor neuropathy (dHMN), a group of diseases characterized by length-dependent axonal degeneration of motor neurons. We have generated induced pluripotent stem cell (iPSC)-derived motor neurons from a patient with the p.T994I ATP7A gene mutation as an in vitro model for X-linked dHMN (dHMNX). Patient motor neurons show a marked reduction of ATP7A protein levels in the soma when compared to control motor neurons and failed to upregulate expression of ATP7A under copper-loading conditions. These results recapitulate previous findings obtained in dHMNX patient fibroblasts and in primary cells from a rodent model of dHMNX, indicating that patient iPSC-derived motor neurons will be an important resource for studying the role of copper in the pathogenic processes that lead to axonal degeneration in dHMNX.
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Affiliation(s)
- Gonzalo Perez-Siles
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Sydney, 2139 NSW, Australia .,Sydney Medical School, University of Sydney, Sydney, 2050 NSW, Australia
| | - Anthony Cutrupi
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Sydney, 2139 NSW, Australia.,Sydney Medical School, University of Sydney, Sydney, 2050 NSW, Australia
| | - Melina Ellis
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Sydney, 2139 NSW, Australia
| | - Jakob Kuriakose
- School of Life Sciences, University of Technology Sydney, Sydney, 2007 NSW, Australia
| | - Sharon La Fontaine
- Centre for Cellular and Molecular Biology, School of Life and Environmental Sciences, Deakin University, Burwood, 3125 VIC, Australia
| | - Di Mao
- Institute for Integrated Cell-Material Sciences and Institute for Chemical Research, Kyoto University, Kyoto 606-8302, Japan
| | - Motonari Uesugi
- Institute for Integrated Cell-Material Sciences and Institute for Chemical Research, Kyoto University, Kyoto 606-8302, Japan
| | - Reinaldo I Takata
- Sarah Network Rehabilitation Hospitals, Brasilia, 70297-400 DF, Brazil
| | | | - Garth Nicholson
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Sydney, 2139 NSW, Australia.,Sydney Medical School, University of Sydney, Sydney, 2050 NSW, Australia.,Molecular Medicine Laboratory, Concord Repatriation General Hospital, Sydney, 2139 NSW, Australia
| | - Marina L Kennerson
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Sydney, 2139 NSW, Australia .,Sydney Medical School, University of Sydney, Sydney, 2050 NSW, Australia.,Molecular Medicine Laboratory, Concord Repatriation General Hospital, Sydney, 2139 NSW, Australia
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6
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Chen YC, Taylor AJ, Verchere CB. Islet prohormone processing in health and disease. Diabetes Obes Metab 2018; 20 Suppl 2:64-76. [PMID: 30230179 DOI: 10.1111/dom.13401] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 05/30/2018] [Accepted: 05/30/2018] [Indexed: 12/15/2022]
Abstract
Biosynthesis of peptide hormones by pancreatic islet endocrine cells is a tightly orchestrated process that is critical for metabolic homeostasis. Like neuroendocrine peptides, insulin and other islet hormones are first synthesized as larger precursor molecules that are processed to their mature secreted products through a series of proteolytic cleavages, mediated by the prohormone convertases Pc1/3 and Pc2, and carboxypeptidase E. Additional posttranslational modifications including C-terminal amidation of the β-cell peptide islet amyloid polypeptide (IAPP) by peptidyl-glycine α-amidating monooxygenase (Pam) may also occur. Genome-wide association studies (GWAS) have showed genetic linkage of these processing enzymes to obesity, β-cell dysfunction, and type 2 diabetes (T2D), pointing to their important roles in metabolism and blood glucose regulation. In both type 1 diabetes (T1D) and T2D, and in the face of metabolic or inflammatory stresses, islet prohormone processing may become impaired; indeed elevated proinsulin:insulin (PI:I) ratios are a hallmark of the β-cell dysfunction in T2D. Recent studies suggest that genetic or acquired defects in proIAPP processing may lead to the production and secretion of incompletely processed forms of proIAPP that could contribute to T2D pathogenesis, and additionally that impaired processing of both PI and proIAPP may be characteristic of β-cell dysfunction in T1D. In islet α-cells, the prohormone proglucagon is normally processed to bioactive glucagon by Pc2 but may express Pc1/3 under certain conditions leading to production of GLP-1(7-36NH2 ). A better understanding of how β-cell processing of PI and proIAPP, as well as α-cell processing of proglucagon, are impacted by genetic susceptibility and in the face of diabetogenic stresses, may lead to new therapeutic approaches for improving islet function in diabetes.
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Affiliation(s)
- Yi-Chun Chen
- Department of Surgery, BC Children's Hospital Research Institute and University of British Columbia, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, BC Children's Hospital Research Institute and University of British Columbia, Vancouver, British Columbia, Canada
| | - Austin J Taylor
- Department of Surgery, BC Children's Hospital Research Institute and University of British Columbia, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, BC Children's Hospital Research Institute and University of British Columbia, Vancouver, British Columbia, Canada
| | - C Bruce Verchere
- Department of Surgery, BC Children's Hospital Research Institute and University of British Columbia, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, BC Children's Hospital Research Institute and University of British Columbia, Vancouver, British Columbia, Canada
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7
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New insights into the pharmacogenomics of antidepressant response from the GENDEP and STAR*D studies: rare variant analysis and high-density imputation. THE PHARMACOGENOMICS JOURNAL 2017; 18:413-421. [DOI: 10.1038/tpj.2017.44] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 06/02/2017] [Accepted: 06/07/2017] [Indexed: 12/27/2022]
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8
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Abstract
Copper is an essential trace metal that is required for several important biological processes, however, an excess of copper can be toxic to cells. Therefore, systemic and cellular copper homeostasis is tightly regulated, but dysregulation of copper homeostasis may occur in disease states, resulting either in copper deficiency or copper overload and toxicity. This chapter will give an overview on the biological roles of copper and of the mechanisms involved in copper uptake, storage, and distribution. In addition, we will describe potential mechanisms of the cellular toxicity of copper and copper oxide nanoparticles. Finally, we will summarize the current knowledge on the connection of copper toxicity with neurodegenerative diseases.
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Affiliation(s)
- Felix Bulcke
- Center for Biomolecular Interactions Bremen, Faculty 2 (Biology/Chemistry), University of Bremen, Bremen, Germany
- Center for Environmental Research and Sustainable Technology, Bremen, Germany
| | - Ralf Dringen
- Center for Biomolecular Interactions Bremen, Faculty 2 (Biology/Chemistry), University of Bremen, Bremen, Germany
- Center for Environmental Research and Sustainable Technology, Bremen, Germany
| | - Ivo Florin Scheiber
- Center for Biomolecular Interactions Bremen, Faculty 2 (Biology/Chemistry), University of Bremen, Bremen, Germany.
- Center for Environmental Research and Sustainable Technology, Bremen, Germany.
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9
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Lu L, Pandey AK, Houseal MT, Mulligan MK. The Genetic Architecture of Murine Glutathione Transferases. PLoS One 2016; 11:e0148230. [PMID: 26829228 PMCID: PMC4734686 DOI: 10.1371/journal.pone.0148230] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 01/14/2016] [Indexed: 12/17/2022] Open
Abstract
Glutathione S-transferase (GST) genes play a protective role against oxidative stress and may influence disease risk and drug pharmacokinetics. In this study, massive multiscalar trait profiling across a large population of mice derived from a cross between C57BL/6J (B6) and DBA2/J (D2)—the BXD family—was combined with linkage and bioinformatic analyses to characterize mechanisms controlling GST expression and to identify downstream consequences of this variation. Similar to humans, mice show a wide range in expression of GST family members. Variation in the expression of Gsta4, Gstt2, Gstz1, Gsto1, and Mgst3 is modulated by local expression QTLs (eQTLs) in several tissues. Higher expression of Gsto1 in brain and liver of BXD strains is strongly associated (P < 0.01) with inheritance of the B6 parental allele whereas higher expression of Gsta4 and Mgst3 in brain and liver, and Gstt2 and Gstz1 in brain is strongly associated with inheritance of the D2 parental allele. Allele-specific assays confirmed that expression of Gsto1, Gsta4, and Mgst3 are modulated by sequence variants within or near each gene locus. We exploited this endogenous variation to identify coexpression networks and downstream targets in mouse and human. Through a combined systems genetics approach, we provide new insight into the biological role of naturally occurring variants in GST genes.
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Affiliation(s)
- Lu Lu
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, 38106, United States of America
- Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, 226001, China
| | - Ashutosh K. Pandey
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, 38106, United States of America
| | - M. Trevor Houseal
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, 38106, United States of America
| | - Megan K. Mulligan
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, 38106, United States of America
- * E-mail:
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10
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Maureira C, Letelier JC, Alvarez O, Delgado R, Vergara C. Copper enhances cellular and network excitabilities, and improves temporal processing in the rat hippocampus. Eur J Neurosci 2015; 42:3066-80. [PMID: 26470005 DOI: 10.1111/ejn.13104] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 10/03/2015] [Indexed: 11/27/2022]
Abstract
Copper, an ion with many important metabolic functions, has also been proposed to have a role as modulator on neuronal function, mostly based on its effects on voltage- and neurotransmitter-gated conductance as well as on neurological symptoms of patients with altered copper homeostasis. Nevertheless, the mechanisms by which copper exerts its neuromodulatory effects have not been clearly established in a functional neuronal network. Using rat hippocampus slices as a neuronal network model, the effects of copper in the range of 10-100 nm were tested on the intrinsic, synaptic and network properties of the CA1 region. Most of the previously described effects of this cation were in the micromolar range of copper concentrations. The current results indicate that copper is a multifaceted neuromodulator, having effects that may be grouped into two categories: (i) activity enhancement, by modulating synaptic communication and action potential (AP) conductances; and (ii) temporal processing and correlation extraction, by improving reliability and depressing inhibition. Specifically it was found that copper hyperpolarizes AP firing threshold, enhances neuronal and network excitability, modifies CA3-CA1 pathway gain, enhances the frequency of spontaneous synaptic events, decreases inhibitory network activity, and improves AP timing reliability. Moreover, copper chelation by bathocuproine decreases spontaneous network spiking activity. These results allow the proposal that copper affects the network activity from cellular to circuit levels on a moment-by-moment basis, and should be considered a crucial functional component of hippocampal neuronal circuitry.
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Affiliation(s)
- Carlos Maureira
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago 7800003, Chile
| | - Juan Carlos Letelier
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago 7800003, Chile
| | - Osvaldo Alvarez
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago 7800003, Chile
| | - Ricardo Delgado
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago 7800003, Chile
| | - Cecilia Vergara
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago 7800003, Chile
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11
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Carlson K, Pomerantz SC, Vafa O, Naso M, Strohl W, Mains RE, Eipper BA. Optimizing production of Fc-amidated peptides by Chinese hamster ovary cells. BMC Biotechnol 2015; 15:95. [PMID: 26475607 PMCID: PMC4609047 DOI: 10.1186/s12896-015-0210-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Accepted: 10/01/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Amidation of the carboxyl terminal of many peptides is essential for full biological potency, often increasing receptor binding and stability. The single enzyme responsible for this reaction is peptidylglycine α-amidating monooxygenase (PAM: EC 1.14.17.3), a copper- and ascorbate-dependent Type I membrane protein. METHODS To make large amounts of high molecular weight amidated product, Chinese hamster ovary (CHO) cells were engineered to express exogenous PAM. To vary access of the enzyme to its substrate, exogenous PAM was targeted to the endoplasmic reticulum, trans-Golgi network, endosomes and lysosomes or to the lumen of the secretory pathway. RESULTS PAM was equally active when targeted to each intracellular location and assayed in homogenates. Immunocytochemical analyses of CHO cells and a pituitary cell line demonstrated that targeting of exogenous PAM was partially successful. PAM substrates generated by expressing peptidylglycine substrates (glucagon-like peptide 1-Gly, peptide YY-Gly and neuromedin U-Gly) fused to the C-terminus of immunoglobulin Fc in CHO cell lines producing targeted PAM. The extent of amidation of the Fc-peptides was determined by mass spectrometry and amidation-specific enzyme immunoassays. Amidation was inhibited by copper chelation, but was not enhanced by the addition of additional copper or ascorbate. CONCLUSIONS Peptide amidation was increased over endogenous levels by exogenous PAM, and targeting PAM to the endoplasmic reticulum or trans-Golgi network increased peptide amidation compared to endogenous CHO PAM.
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Affiliation(s)
- Kristina Carlson
- Department of Neuroscience, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT, 06030-3401, USA.
| | - Steven C Pomerantz
- Biologics Research, Biotechnology Center of Excellence, Janssen Research & Development, LLC, Spring House, PA, 19477, USA.
| | - Omid Vafa
- Biologics Research, Biotechnology Center of Excellence, Janssen Research & Development, LLC, Spring House, PA, 19477, USA.
| | - Michael Naso
- Biologics Research, Biotechnology Center of Excellence, Janssen Research & Development, LLC, Spring House, PA, 19477, USA.
| | - William Strohl
- Biologics Research, Biotechnology Center of Excellence, Janssen Research & Development, LLC, Spring House, PA, 19477, USA.
| | - Richard E Mains
- Department of Neuroscience, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT, 06030-3401, USA.
| | - Betty A Eipper
- Department of Neuroscience, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT, 06030-3401, USA. .,Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT, 06030, USA.
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12
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Lal D, Ruppert AK, Trucks H, Schulz H, de Kovel CG, Kasteleijn-Nolst Trenité D, Sonsma ACM, Koeleman BP, Lindhout D, Weber YG, Lerche H, Kapser C, Schankin CJ, Kunz WS, Surges R, Elger CE, Gaus V, Schmitz B, Helbig I, Muhle H, Stephani U, Klein KM, Rosenow F, Neubauer BA, Reinthaler EM, Zimprich F, Feucht M, Møller RS, Hjalgrim H, De Jonghe P, Suls A, Lieb W, Franke A, Strauch K, Gieger C, Schurmann C, Schminke U, Nürnberg P, Sander T. Burden analysis of rare microdeletions suggests a strong impact of neurodevelopmental genes in genetic generalised epilepsies. PLoS Genet 2015; 11:e1005226. [PMID: 25950944 PMCID: PMC4423931 DOI: 10.1371/journal.pgen.1005226] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 04/16/2015] [Indexed: 01/06/2023] Open
Abstract
Genetic generalised epilepsy (GGE) is the most common form of genetic epilepsy, accounting for 20% of all epilepsies. Genomic copy number variations (CNVs) constitute important genetic risk factors of common GGE syndromes. In our present genome-wide burden analysis, large (≥ 400 kb) and rare (< 1%) autosomal microdeletions with high calling confidence (≥ 200 markers) were assessed by the Affymetrix SNP 6.0 array in European case-control cohorts of 1,366 GGE patients and 5,234 ancestry-matched controls. We aimed to: 1) assess the microdeletion burden in common GGE syndromes, 2) estimate the relative contribution of recurrent microdeletions at genomic rearrangement hotspots and non-recurrent microdeletions, and 3) identify potential candidate genes for GGE. We found a significant excess of microdeletions in 7.3% of GGE patients compared to 4.0% in controls (P = 1.8 x 10-7; OR = 1.9). Recurrent microdeletions at seven known genomic hotspots accounted for 36.9% of all microdeletions identified in the GGE cohort and showed a 7.5-fold increased burden (P = 2.6 x 10-17) relative to controls. Microdeletions affecting either a gene previously implicated in neurodevelopmental disorders (P = 8.0 x 10-18, OR = 4.6) or an evolutionarily conserved brain-expressed gene related to autism spectrum disorder (P = 1.3 x 10-12, OR = 4.1) were significantly enriched in the GGE patients. Microdeletions found only in GGE patients harboured a high proportion of genes previously associated with epilepsy and neuropsychiatric disorders (NRXN1, RBFOX1, PCDH7, KCNA2, EPM2A, RORB, PLCB1). Our results demonstrate that the significantly increased burden of large and rare microdeletions in GGE patients is largely confined to recurrent hotspot microdeletions and microdeletions affecting neurodevelopmental genes, suggesting a strong impact of fundamental neurodevelopmental processes in the pathogenesis of common GGE syndromes.
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Affiliation(s)
- Dennis Lal
- Cologne Center for Genomics (CCG), University of Cologne, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
- Department of Neuropediatrics, University Medical Center Giessen and Marburg, Giessen, Germany
- EPICURE Consortium
| | - Ann-Kathrin Ruppert
- Cologne Center for Genomics (CCG), University of Cologne, Cologne, Germany
- EPICURE Consortium
| | - Holger Trucks
- Cologne Center for Genomics (CCG), University of Cologne, Cologne, Germany
- EPICURE Consortium
| | - Herbert Schulz
- Cologne Center for Genomics (CCG), University of Cologne, Cologne, Germany
- EPICURE Consortium
| | - Carolien G. de Kovel
- EPICURE Consortium
- Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Anja C. M. Sonsma
- EPICURE Consortium
- Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Bobby P. Koeleman
- EPICURE Consortium
- Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Dick Lindhout
- EPICURE Consortium
- Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
- SEIN Epilepsy Institute in the Netherlands, Hoofddorp, The Netherlands
| | - Yvonne G. Weber
- EPICURE Consortium
- Department of Neurology and Epileptology, Hertie Institute of Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Holger Lerche
- EPICURE Consortium
- Department of Neurology and Epileptology, Hertie Institute of Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Claudia Kapser
- EPICURE Consortium
- Department of Neurology, University of Munich Hospital—Großhadern, Munich, Germany
| | - Christoph J. Schankin
- EPICURE Consortium
- Department of Neurology, University of Munich Hospital—Großhadern, Munich, Germany
| | - Wolfram S. Kunz
- EPICURE Consortium
- Department of Epileptology, University Clinics Bonn, Bonn, Germany
| | - Rainer Surges
- EPICURE Consortium
- Department of Epileptology, University Clinics Bonn, Bonn, Germany
| | - Christian E. Elger
- EPICURE Consortium
- Department of Epileptology, University Clinics Bonn, Bonn, Germany
| | - Verena Gaus
- EPICURE Consortium
- Department of Neurology, Charité University Medicine, Campus Virchow Clinic, Berlin, Germany
| | - Bettina Schmitz
- EPICURE Consortium
- Department of Neurology, Charité University Medicine, Campus Virchow Clinic, Berlin, Germany
- Department of Neurology, Vivantes Humboldt-Klinikum, Berlin, Germany
| | - Ingo Helbig
- EPICURE Consortium
- Department of Neuropediatrics, University Medical Center Schleswig-Holstein (Kiel Campus), Kiel, Germany
| | - Hiltrud Muhle
- EPICURE Consortium
- Department of Neuropediatrics, University Medical Center Schleswig-Holstein (Kiel Campus), Kiel, Germany
| | - Ulrich Stephani
- EPICURE Consortium
- Department of Neuropediatrics, University Medical Center Schleswig-Holstein (Kiel Campus), Kiel, Germany
| | - Karl M. Klein
- EPICURE Consortium
- Epilepsy-Center Hessen, Department of Neurology, Philipps-University Marburg, Marburg, Germany
- Epilepsy Center Frankfurt Rhein-Main, Department of Neurology, Johann Wolfgang Goethe University Frankfurt, Frankfurt, Germany
| | - Felix Rosenow
- EPICURE Consortium
- Epilepsy-Center Hessen, Department of Neurology, Philipps-University Marburg, Marburg, Germany
- Epilepsy Center Frankfurt Rhein-Main, Department of Neurology, Johann Wolfgang Goethe University Frankfurt, Frankfurt, Germany
| | - Bernd A. Neubauer
- Department of Neuropediatrics, University Medical Center Giessen and Marburg, Giessen, Germany
| | - Eva M. Reinthaler
- EPICURE Consortium
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Fritz Zimprich
- EPICURE Consortium
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Martha Feucht
- EPICURE Consortium
- Department of Pediatrics and Neonatology, Medical University of Vienna, Vienna, Austria
| | - Rikke S. Møller
- EPICURE Consortium
- Department of Neurology, Danish Epilepsy Centre, Dianalund, Denmark
- Institute for Regional Health Services, University of Southern Denmark, Odense, Denmark
| | - Helle Hjalgrim
- EPICURE Consortium
- Department of Neurology, Danish Epilepsy Centre, Dianalund, Denmark
- Institute for Regional Health Services, University of Southern Denmark, Odense, Denmark
| | - Peter De Jonghe
- EPICURE Consortium
- Neurogenetics Group, VIB Department of Molecular Genetics, University of Antwerp, Antwerp, Belgium
- Laboratory of Neurogenetics, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium
| | - Arvid Suls
- EPICURE Consortium
- Neurogenetics Group, VIB Department of Molecular Genetics, University of Antwerp, Antwerp, Belgium
- Laboratory of Neurogenetics, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium
| | - Wolfgang Lieb
- Institute of Epidemiology and Biobank Popgen, Christian Albrechts University, Kiel, Germany
| | - Andre Franke
- Institute of Clinical Molecular Biology, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Konstantin Strauch
- Institute of Genetic Epidemiology, Helmholtz Zentrum München—German Research Center for Environmental Health, Neuherberg, Germany
- Institute of Medical Informatics, Biometry and Epidemiology, and Chair of Genetic Epidemiology, Ludwig-Maximilians-University, Munich, Germany
| | - Christian Gieger
- Institute of Genetic Epidemiology, Helmholtz Zentrum München—German Research Center for Environmental Health, Neuherberg, Germany
- Research Unit of Molecular Epidemiology, Helmholtz Zentrum München—German Research Center for Environmental Health, Neuherberg, Germany
- Institute of Epidemiology II, Helmholtz Zentrum München—German Research Center for Environmental Health, Neuherberg, Germany
| | - Claudia Schurmann
- Interfaculty Institute for Genetics and Functional Genomics, Ernst Moritz Arndt University, Greifswald, Germany
| | - Ulf Schminke
- Department of Neurology, University Medicine Greifswald, Ernst Moritz Arndt University, Greifswald, Germany
| | - Peter Nürnberg
- Cologne Center for Genomics (CCG), University of Cologne, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
- EPICURE Consortium
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | | | - Thomas Sander
- Cologne Center for Genomics (CCG), University of Cologne, Cologne, Germany
- EPICURE Consortium
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Zlatic S, Comstra HS, Gokhale A, Petris MJ, Faundez V. Molecular basis of neurodegeneration and neurodevelopmental defects in Menkes disease. Neurobiol Dis 2015; 81:154-61. [PMID: 25583185 DOI: 10.1016/j.nbd.2014.12.024] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 12/04/2014] [Accepted: 12/23/2014] [Indexed: 12/16/2022] Open
Abstract
ATP7A mutations impair copper metabolism resulting in three distinct genetic disorders in humans. These diseases are characterized by neurological phenotypes ranging from intellectual disability to neurodegeneration. Severe ATP7A loss-of-function alleles trigger Menkes disease, a copper deficiency condition where systemic and neurodegenerative phenotypes dominate clinical outcomes. The pathogenesis of these manifestations has been attributed to the hypoactivity of a limited number of copper-dependent enzymes, a hypothesis that we refer as the oligoenzymatic pathogenic hypothesis. This hypothesis, which has dominated the field for 25 years, only explains some systemic Menkes phenotypes. However, we argue that this hypothesis does not fully account for the Menkes neurodegeneration or neurodevelopmental phenotypes. Here, we propose revisions of the oligoenzymatic hypothesis that could illuminate the pathogenesis of Menkes neurodegeneration and neurodevelopmental defects through unsuspected overlap with other neurological conditions including Parkinson's, intellectual disability, and schizophrenia.
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Affiliation(s)
- Stephanie Zlatic
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA
| | | | - Avanti Gokhale
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA
| | - Michael J Petris
- Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA
| | - Victor Faundez
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA; Center for Social Translational Neuroscience, Emory University, Atlanta, GA 30322, USA.
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14
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Castro PA, Ramirez A, Sepúlveda FJ, Peters C, Fierro H, Waldron J, Luza S, Fuentealba J, Muñoz FJ, De Ferrari GV, Bush AI, Aguayo LG, Opazo CM. Copper-uptake is critical for the down regulation of synapsin and dynamin induced by neocuproine: modulation of synaptic activity in hippocampal neurons. Front Aging Neurosci 2014; 6:319. [PMID: 25520655 PMCID: PMC4253966 DOI: 10.3389/fnagi.2014.00319] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 10/30/2014] [Indexed: 01/08/2023] Open
Abstract
Extracellular and intracellular copper and zinc regulate synaptic activity and plasticity, which may impact brain functionality and human behavior. We have found that a metal coordinating molecule, Neocuproine, transiently increases free intracellular copper and zinc levels (i.e., min) in hippocampal neurons as monitored by Phen Green and FluoZin-3 fluorescence, respectively. The changes in free intracellular zinc induced by Neocuproine were abolished by the presence of a non-permeant copper chelator, Bathocuproine (BC), indicating that copper influx is needed for the action of Neocuproine on intracellular Zn levels. Moreover, Neocuproine decreased the mRNA levels of Synapsin and Dynamin, and did not affect the expression of Bassoon, tubulin or superoxide dismutase (SOD). Western blot analysis showed that protein levels of synapsin and dynamin were also down regulated in the presence of Neocuproine and that these changes were accompanied by a decrease in calcium transients and neuronal activity. Furthermore, Neocuproine decreased the number of active neurons, effect that was blocked by the presence of BC, indicating that copper influx is needed for the action of Neocuproine. We finally show that Neocuproine blocks the epileptiform-like activity induced by bicuculline in hippocampal neurons. Collectively, our data indicates that presynaptic protein configuration and function of primary hippocampal neurons is sensitive to transient changes in transition metal homeostasis. Therefore, small molecules able to coordinate transition metals and penetrate the blood-brain barrier might modify neurotransmission at the Central Nervous System (CNS). This might be useful to establish therapeutic approaches to control the neuronal hyperexcitabiltity observed in brain conditions that are associated to copper dyshomeotasis such as Alzheimer’s and Menkes diseases. Our work also opens a new avenue to find novel and effective antiepilepsy drugs based in metal coordinating molecules.
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Affiliation(s)
- Patricio A Castro
- Department of Physiology and Membrane Biology, Shriners Hospital for Children Northern California, University of California at Davis School of Medicine California, USA
| | - Alejandra Ramirez
- Laboratorio de Neurofisiología, Departamento de Fisiología, Facultad de Ciencias Biológicas, Universidad de Concepción Concepción, Chile ; Oxidation Biology Laboratory, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne Parkville, Melbourne, Victoria, Australia
| | - Fernando J Sepúlveda
- Laboratorio de Neurofisiología, Departamento de Fisiología, Facultad de Ciencias Biológicas, Universidad de Concepción Concepción, Chile
| | - Christian Peters
- Laboratorio de Neurofisiología, Departamento de Fisiología, Facultad de Ciencias Biológicas, Universidad de Concepción Concepción, Chile
| | - Humberto Fierro
- Laboratorio de Neurofisiología, Departamento de Fisiología, Facultad de Ciencias Biológicas, Universidad de Concepción Concepción, Chile
| | - Javier Waldron
- Laboratorio de Neurofisiología, Departamento de Fisiología, Facultad de Ciencias Biológicas, Universidad de Concepción Concepción, Chile
| | - Sandra Luza
- Oxidation Biology Laboratory, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne Parkville, Melbourne, Victoria, Australia
| | - Jorge Fuentealba
- Laboratorio de Neurofisiología, Departamento de Fisiología, Facultad de Ciencias Biológicas, Universidad de Concepción Concepción, Chile
| | - Francisco J Muñoz
- Laboratory of Molecular Physiology and Channelopathies, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra Barcelona, Spain
| | - Giancarlo V De Ferrari
- Center for Biomedical Research and FONDAP Center for Genome Regulation, Universidad Andrés Bello Santiago, Chile
| | - Ashley I Bush
- Oxidation Biology Laboratory, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne Parkville, Melbourne, Victoria, Australia
| | - Luis G Aguayo
- Laboratorio de Neurofisiología, Departamento de Fisiología, Facultad de Ciencias Biológicas, Universidad de Concepción Concepción, Chile
| | - Carlos M Opazo
- Oxidation Biology Laboratory, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne Parkville, Melbourne, Victoria, Australia
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15
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Gaier ED, Kleppinger A, Ralle M, Covault J, Mains RE, Kenny AM, Eipper BA. Genetic determinants of amidating enzyme activity and its relationship with metal cofactors in human serum. BMC Endocr Disord 2014; 14:58. [PMID: 25022877 PMCID: PMC4113131 DOI: 10.1186/1472-6823-14-58] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Accepted: 07/07/2014] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND α-amidation is a final, essential step in the biosynthesis of about half of all peptide hormones and neurotransmitters. Peptidylglycine α-amidating monooxygenase (PAM), with enzymatic domains that utilize Cu and Zn, is the only enzyme that catalyzes this reaction. PAM activity is detected in serum, but its significance and utility as a clinical biomarker remain unexplored. METHODS We used well-established enzymatic assays specific for the peptidylglycine-α -hydroxylating monooxygenase (PHM) and peptidyl-α-hydroxyglycine α-amidating lyase (PAL) domains of PAM to quantify amidating activity in the sera of 144 elderly men. Relationships between PHM and PAL activity and serum levels of their respective active-site metals, Cu and Zn, were analyzed. Study participants were also genotyped for eight non-coding single nucleotide polymorphisms (SNPs) in PAM, and relationships between genotype and serum enzyme activity and metal levels were analyzed. RESULTS Serum PHM and PAL activities were normally distributed and correlated linearly with each other. Serum PAL activity, but not serum PHM activity, correlated with serum Cu; neither activity correlated with serum Zn. Study subjects possessing the minor alleles for rs32680 had lower PHM and PAL activities, and subjects with minor alleles for rs11952361 and rs10515341 had lower PHM activities. CONCLUSIONS Our results characterize large variation in serum amidating activity and provide unique insight into its potential origin and determinants. Common non-coding polymorphisms affect serum amidating activity and Cu levels. Serum amidating activity should be explored as a biomarker for functionality in the elderly and in additional study groups.
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Affiliation(s)
- Eric D Gaier
- Department of Neuroscience, University of Connecticut Health Center, 06030 Farmington, CT, USA
| | - Alison Kleppinger
- Center on Aging, University of Connecticut Health Center, 06030 Farmington, CT, USA
| | - Martina Ralle
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, 97239 Portland, OR, USA
| | - Jonathan Covault
- Department of Neuroscience, University of Connecticut Health Center, 06030 Farmington, CT, USA
- Department of Psychiatry, University of Connecticut Health Center, 06030 Farmington, CT, USA
| | - Richard E Mains
- Department of Neuroscience, University of Connecticut Health Center, 06030 Farmington, CT, USA
| | - Anne M Kenny
- Center on Aging, University of Connecticut Health Center, 06030 Farmington, CT, USA
| | - Betty A Eipper
- Department of Neuroscience, University of Connecticut Health Center, 06030 Farmington, CT, USA
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16
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Opazo CM, Greenough MA, Bush AI. Copper: from neurotransmission to neuroproteostasis. Front Aging Neurosci 2014; 6:143. [PMID: 25071552 PMCID: PMC4080678 DOI: 10.3389/fnagi.2014.00143] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 06/16/2014] [Indexed: 01/23/2023] Open
Abstract
Copper is critical for the Central Nervous System (CNS) development and function. In particular, different studies have shown the effect of copper at brain synapses, where it inhibits Long Term Potentation (LTP) and receptor pharmacology. Paradoxically, according to recent studies copper is required for a normal LTP response. Copper is released at the synaptic cleft, where it blocks glutamate receptors, which explain its blocking effects on excitatory neurotransmission. Our results indicate that copper also enhances neurotransmission through the accumulation of PSD95 protein, which increase the levels of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors located at the plasma membrane of the post-synaptic density. Thus, our findings represent a novel mechanism for the action of copper, which may have implications for the neurophysiology and neuropathology of the CNS. These data indicate that synaptic configuration is sensitive to transient changes in transition metal homeostasis. Our results suggest that copper increases GluA1 subunit levels of the AMPA receptor through the anchorage of AMPA receptors to the plasma membrane as a result of PSD-95 accumulation. Here, we will review the role of copper on neurotransmission of CNS neurons. In addition, we will discuss the potential mechanisms by which copper could modulate neuronal proteostasis (“neuroproteostasis”) in the CNS with focus in the Ubiquitin Proteasome System (UPS), which is particularly relevant to neurological disorders such as Alzheimer’s disease (AD) where copper and protein dyshomeostasis may contribute to neurodegeneration. An understanding of these mechanisms may ultimately lead to the development of novel therapeutic approaches to control metal and synaptic alterations observed in AD patients.
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Affiliation(s)
- Carlos M Opazo
- Oxidation Biology Laboratory, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne Melbourne, VIC, Australia
| | - Mark A Greenough
- Oxidation Biology Laboratory, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne Melbourne, VIC, Australia
| | - Ashley I Bush
- Oxidation Biology Laboratory, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne Melbourne, VIC, Australia
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