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Gkouvi A, Tsiogkas SG, Bogdanos DP, Gika H, Goulis DG, Grammatikopoulou MG. Proteomics in Patients with Fibromyalgia Syndrome: A Systematic Review of Observational Studies. Curr Pain Headache Rep 2024; 28:565-586. [PMID: 38652420 PMCID: PMC11271354 DOI: 10.1007/s11916-024-01244-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/16/2024] [Indexed: 04/25/2024]
Abstract
PURPOSE OF REVIEW Fibromyalgia syndrome (FMS) is a disease of unknown pathophysiology, with the diagnosis being based on a set of clinical criteria. Proteomic analysis can provide significant biological information for the pathophysiology of the disease but may also reveal biomarkers for diagnosis or therapeutic targets. The present systematic review aims to synthesize the evidence regarding the proteome of adult patients with FMS using data from observational studies. RECENT FINDINGS An extensive literature search was conducted in MEDLINE/PubMed, CENTRAL, and clinicaltrials.gov from inception until November 2022. The study protocol was published in OSF. Two independent reviewers evaluated the studies and extracted data. The quality of studies was assessed using the modified Newcastle-Ottawa scale adjusted for proteomic research. Ten studies fulfilled the protocol criteria, identifying 3328 proteins, 145 of which were differentially expressed among patients with FMS against controls. The proteins were identified in plasma, serum, cerebrospinal fluid, and saliva samples. The control groups included healthy individuals and patients with pain (inflammatory and non-inflammatory). The most important proteins identified involved transferrin, α-, β-, and γ-fibrinogen chains, profilin-1, transaldolase, PGAM1, apolipoprotein-C3, complement C4A and C1QC, immunoglobin parts, and acute phase reactants. Weak correlations were observed between proteins and pain sensation, or quality of life scales, apart from the association of transferrin and a2-macroglobulin with moderate-to-severe pain sensation. The quality of included studies was moderate-to-good. FMS appears to be related to protein dysregulation in the complement and coagulation cascades and the metabolism of iron. Several proteins may be dysregulated due to the excessive oxidative stress response.
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Affiliation(s)
- Arriana Gkouvi
- Unit of Immunonutrition and Clinical Nutrition, Department of Rheumatology and Clinical Immunology, Faculty of Medicine, School of Health Sciences, University of Thessaly, Biopolis, Larissa, Greece
| | - Sotirios G Tsiogkas
- Unit of Immunonutrition and Clinical Nutrition, Department of Rheumatology and Clinical Immunology, Faculty of Medicine, School of Health Sciences, University of Thessaly, Biopolis, Larissa, Greece
| | - Dimitrios P Bogdanos
- Unit of Immunonutrition and Clinical Nutrition, Department of Rheumatology and Clinical Immunology, Faculty of Medicine, School of Health Sciences, University of Thessaly, Biopolis, Larissa, Greece.
| | - Helen Gika
- Center for Interdisciplinary Research and Innovation (CIRI-AUTH), Biomic_AUTh, Balkan Center Thermi B1.4, GR-57001, Thessaloniki, Greece
- Laboratory of Forensic Medicine and Toxicology, School of Medicine, Aristotle University of Thessaloniki, GR-54124, Thessaloniki, Greece
| | - Dimitrios G Goulis
- Unit of Reproductive Endocrinology, 1st Department of Obstetrics and Gynecology, Medical School, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Maria G Grammatikopoulou
- Unit of Immunonutrition and Clinical Nutrition, Department of Rheumatology and Clinical Immunology, Faculty of Medicine, School of Health Sciences, University of Thessaly, Biopolis, Larissa, Greece
- Unit of Reproductive Endocrinology, 1st Department of Obstetrics and Gynecology, Medical School, Aristotle University of Thessaloniki, Thessaloniki, Greece
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Chen Z, Wang D, Yu Q, Johnson J, Shipman R, Zhong X, Huang J, Yu Q, Zetterberg H, Asthana S, Carlsson C, Okonkwo O, Li L. In-Depth Site-Specific O-Glycosylation Analysis of Glycoproteins and Endogenous Peptides in Cerebrospinal Fluid (CSF) from Healthy Individuals, Mild Cognitive Impairment (MCI), and Alzheimer's Disease (AD) Patients. ACS Chem Biol 2022; 17:3059-3068. [PMID: 34964596 PMCID: PMC9240109 DOI: 10.1021/acschembio.1c00932] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Site-specific O-glycoproteome mapping in complex biological systems provides a molecular basis for understanding the structure-function relationships of glycoproteins and their roles in physiological and pathological processes. Previous O-glycoproteome analysis in cerebrospinal fluid (CSF) focused on sialylated glycoforms, while missing information on other glycosylation types. In order to achieve an unbiased O-glycosylation profile, we developed an integrated strategy combining universal boronic acid enrichment, high-pH fractionation, and electron-transfer and higher-energy collision dissociation (EThcD) for enhanced intact O-glycopeptide analysis. We applied this strategy to analyze the O-glycoproteome in CSF, resulting in the identification of 308 O-glycopeptides from 110 O-glycoproteins, covering both sialylated and nonsialylated glycoforms. To our knowledge, this is the largest data set of O-glycoproteins and O-glycosites reported for CSF to date. We also developed a peptidomics workflow that utilized the EThcD and a three-step database searching strategy for comprehensive PTM analysis of endogenous peptides, including N-glycosylation, O-glycosylation, and other common peptide PTMs. Interestingly, among the 1411 endogenous peptides identified, 89 were O-glycosylated, and only one N-glycosylated peptide was found, indicating that CSF endogenous peptides were predominantly O-glycosylated. Analyses of the O-glycoproteome and endogenous peptidome PTMs were also conducted in the CSF of MCI and AD patients to provide a landscape of glycosylation patterns in different disease states. Our results showed a decreasing trend in fucosylation and an increasing trend of endogenous peptide O-glycosylation, which may play an important role in AD progression.
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Affiliation(s)
- Zhengwei Chen
- Department of Chemistry, University of Wisconsin, Madison, WI 53706, USA
| | - Danqing Wang
- Department of Chemistry, University of Wisconsin, Madison, WI 53706, USA
| | - Qing Yu
- School of Pharmacy, University of Wisconsin, Madison, WI 53705, USA
| | - Jillian Johnson
- School of Pharmacy, University of Wisconsin, Madison, WI 53705, USA
| | - Richard Shipman
- Applied Science Program, University of Wisconsin-Stout, Menomonie, WI 54751, USA
| | - Xiaofang Zhong
- School of Pharmacy, University of Wisconsin, Madison, WI 53705, USA
| | - Junfeng Huang
- School of Pharmacy, University of Wisconsin, Madison, WI 53705, USA
| | - Qinying Yu
- School of Pharmacy, University of Wisconsin, Madison, WI 53705, USA
| | - Henrik Zetterberg
- Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, 43180, Mölndal, Sweden,Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, 43180, Mölndal, Sweden,Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, United Kingdom,UK Dementia Research Institute at UCL, London, WC1E 6BT, United Kingdom
| | - Sanjay Asthana
- School of Medicine and Public Health, University of Wisconsin, Madison, WI 53726, USA
| | - Cynthia Carlsson
- School of Medicine and Public Health, University of Wisconsin, Madison, WI 53726, USA
| | - Ozioma Okonkwo
- School of Medicine and Public Health, University of Wisconsin, Madison, WI 53726, USA
| | - Lingjun Li
- Department of Chemistry, University of Wisconsin, Madison, WI 53706, USA,School of Pharmacy, University of Wisconsin, Madison, WI 53705, USA,Correspondence: Professor Lingjun Li, School of Pharmacy and Department of Chemistry, University of Wisconsin-Madison, 777 Highland Avenue, Madison, Wisconsin 53705-2222, , Fax: +1-608-262-5345, Phone: +1-608-265-8491
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Aryal DK, Rodriguiz RM, Nguyen NL, Pease MW, Morgan DJ, Pintar J, Fricker LD, Wetsel WC. Mice lacking proSAAS display alterations in emotion, consummatory behavior and circadian entrainment. GENES, BRAIN, AND BEHAVIOR 2022; 21:e12827. [PMID: 35878875 PMCID: PMC9444949 DOI: 10.1111/gbb.12827] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 07/07/2022] [Accepted: 07/07/2022] [Indexed: 11/30/2022]
Abstract
ProSAAS is a neuroendocrine protein that is cleaved by neuropeptide-processing enzymes into more than a dozen products including the bigLEN and PEN peptides, which bind and activate the receptors GPR171 and GPR83, respectively. Previous studies have suggested that proSAAS-derived peptides are involved in physiological functions that include body weight regulation, circadian rhythms and anxiety-like behavior. In the present study, we find that proSAAS knockout mice display robust anxiety-like behaviors in the open field, light-dark emergence and elevated zero maze tests. These mutant mice also show a reduction in cued fear and an impairment in fear-potentiated startle, indicating an important role for proSAAS-derived peptides in emotional behaviors. ProSAAS knockout mice exhibit reduced water consumption and urine production relative to wild-type controls. No differences in food consumption and overall energy expenditure were observed between the genotypes. However, the respiratory exchange ratio was elevated in the mutants during the light portion of the light-dark cycle, indicating decreased fat metabolism during this period. While proSAAS knockout mice show normal circadian patterns of activity, even upon long-term exposure to constant darkness, they were unable to shift their circadian clock upon exposure to a light pulse. Taken together, these results show that proSAAS-derived peptides modulate a wide range of behaviors including emotion, metabolism and the regulation of the circadian clock.
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Affiliation(s)
- Dipendra K. Aryal
- Department of Psychiatry and Behavioral SciencesDuke University Medical CenterDurhamNorth CarolinaUSA
| | - Ramona M. Rodriguiz
- Department of Psychiatry and Behavioral SciencesDuke University Medical CenterDurhamNorth CarolinaUSA,Department of Psychiatry and Behavioral Sciences, Mouse Behavioral and Neuroendocrine Analysis Core FacilityDuke University Medical CenterDurhamNorth CarolinaUSA
| | - Ngoc Lien Nguyen
- Department of Psychiatry and Behavioral SciencesDuke University Medical CenterDurhamNorth CarolinaUSA
| | - Matthew W. Pease
- Department of Psychiatry and Behavioral SciencesDuke University Medical CenterDurhamNorth CarolinaUSA
| | - Daniel J. Morgan
- Department of Anesthesiology and Perioperative Medicine, Pennsylvania StateUniversity College of MedicineHersheyPennsylvaniaUSA
| | - John Pintar
- Department of Neuroscience and Cell BiologyRutgers Robert Wood Johnson Medical SchoolPiscatawayNew JerseyUSA
| | - Lloyd D. Fricker
- Departments of Molecular Pharmacology and NeuroscienceAlbert Einstein College of MedicineBronxNew YorkUSA
| | - William C. Wetsel
- Department of Psychiatry and Behavioral Sciences, Mouse Behavioral and Neuroendocrine Analysis Core FacilityDuke University Medical CenterDurhamNorth CarolinaUSA,Department of Cell BiologyDuke University Medical CenterDurhamNorth CarolinaUSA,Department of NeurobiologyDuke University Medical CenterDurhamNCUSA
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Mack SM, Gomes I, Fakira AK, Duarte ML, Gupta A, Fricker L, Devi LA. GPR83 engages endogenous peptides from two distinct precursors to elicit differential signaling. Mol Pharmacol 2022; 102:MOLPHARM-AR-2022-000487. [PMID: 35605991 PMCID: PMC9341263 DOI: 10.1124/molpharm.122.000487] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 04/28/2022] [Accepted: 05/03/2022] [Indexed: 09/11/2023] Open
Abstract
PEN is an abundant neuropeptide that activates GPR83, a G protein-coupled receptor that is considered a novel therapeutic target due to its roles in regulation of feeding, reward, and anxiety-related behaviors. The major form of PEN in the brain is 22 residues in length. Previous studies have identified shorter forms of PEN in mouse brain and neuroendocrine cells; these shorter forms were named PEN18, PEN19 and PEN20, with the number reflecting the length of the peptide. The C-terminal five residues of PEN20 are identical to the C-terminus of a procholecystokinin (proCCK)-derived peptide, named proCCK56-62, that is present in mouse brain. ProCCK56-62 is highly conserved across species although it has no homology to the bioactive cholecystokinin domain. ProCCK56-62 and a longer form, proCCK56-63 were tested for their ability to engage GPR83. Both peptides bind GPR83 with high affinity, activate second messenger pathways, and induce ligand-mediated receptor endocytosis. Interestingly, the shorter PEN peptides, ProCC56-62, and ProCCK56-63 differentially activate signal transduction pathways. Whereas PEN22 and PEN20 facilitate receptor coupling to Gai, PEN18, PEN19 and ProCCK peptides facilitate coupling to Gas. Furthermore, the ProCCK peptides exhibit dose dependent Ga subtype selectivity in that they faciliate coupling to Gas at low concentrations and Gai at high concentrations. These data demonstrate that peptides derived from two distinct peptide precursors can differentially activate GPR83, and that GPR83 exhibits Ga subtype preference depending on the nature and concentration of the peptide. These results are consistent with the emerging idea that endogenous neuropeptides function as biased ligands. Significance Statement We found that peptides derived from proCCK bind and activate GPR83, a G protein-coupled receptor that is known to bind peptides derived from proSAAS. Different forms of the proCCK- and proSAAS-derived peptides show biased agonism, activating Gas or Gai depending on the length of the peptide and/or its concentration.
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Affiliation(s)
- Seshat M Mack
- Department of Pharmacological Sciences, Mount Sinai School of Medicine, United States
| | - Ivone Gomes
- Department of Pharmacology & Systems Therapeutics, Mount Sinai School of Medicine, United States
| | - Amanda K Fakira
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, United States
| | - Mariana L Duarte
- Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, United States
| | - Achla Gupta
- Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, United States
| | - Lloyd Fricker
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, United States
| | - Lakshmi A Devi
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, United States
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Chaplot K, Jarvela TS, Lindberg I. Secreted Chaperones in Neurodegeneration. Front Aging Neurosci 2020; 12:268. [PMID: 33192447 PMCID: PMC7481362 DOI: 10.3389/fnagi.2020.00268] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 08/03/2020] [Indexed: 12/11/2022] Open
Abstract
Protein homeostasis, or proteostasis, is a combination of cellular processes that govern protein quality control, namely, protein translation, folding, processing, and degradation. Disruptions in these processes can lead to protein misfolding and aggregation. Proteostatic disruption can lead to cellular changes such as endoplasmic reticulum or oxidative stress; organelle dysfunction; and, if continued, to cell death. A majority of neurodegenerative diseases involve the pathologic aggregation of proteins that subverts normal neuronal function. While prior reviews of neuronal proteostasis in neurodegenerative processes have focused on cytoplasmic chaperones, there is increasing evidence that chaperones secreted both by neurons and other brain cells in the extracellular - including transsynaptic - space play important roles in neuronal proteostasis. In this review, we will introduce various secreted chaperones involved in neurodegeneration. We begin with clusterin and discuss its identification in various protein aggregates, and the use of increased cerebrospinal fluid (CSF) clusterin as a potential biomarker and as a potential therapeutic. Our next secreted chaperone is progranulin; polymorphisms in this gene represent a known genetic risk factor for frontotemporal lobar degeneration, and progranulin overexpression has been found to be effective in reducing Alzheimer's- and Parkinson's-like neurodegenerative phenotypes in mouse models. We move on to BRICHOS domain-containing proteins, a family of proteins containing highly potent anti-amyloidogenic activity; we summarize studies describing the biochemical mechanisms by which recombinant BRICHOS protein might serve as a therapeutic agent. The next section of the review is devoted to the secreted chaperones 7B2 and proSAAS, small neuronal proteins which are packaged together with neuropeptides and released during synaptic activity. Since proteins can be secreted by both classical secretory and non-classical mechanisms, we also review the small heat shock proteins (sHsps) that can be secreted from the cytoplasm to the extracellular environment and provide evidence for their involvement in extracellular proteostasis and neuroprotection. Our goal in this review focusing on extracellular chaperones in neurodegenerative disease is to summarize the most recent literature relating to neurodegeneration for each secreted chaperone; to identify any common mechanisms; and to point out areas of similarity as well as differences between the secreted chaperones identified to date.
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Affiliation(s)
| | | | - Iris Lindberg
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, University of Maryland, Baltimore, Baltimore, MD, United States
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6
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Royds J, Conroy MJ, Dunne MR, Cassidy H, Matallanas D, Lysaght J, McCrory C. Examination and characterisation of burst spinal cord stimulation on cerebrospinal fluid cellular and protein constituents in patient responders with chronic neuropathic pain - A Pilot Study. J Neuroimmunol 2020; 344:577249. [PMID: 32361148 DOI: 10.1016/j.jneuroim.2020.577249] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 03/11/2020] [Accepted: 04/21/2020] [Indexed: 12/19/2022]
Abstract
INTRODUCTION Patients with neuropathic pain have altered proteomic and neuropeptide constituents in cerebrospinal fluid (CSF) compared to controls. Tonic spinal cord stimulation (SCS) has demonstrated differential expression of neuropeptides in CSF before and after treatment suggesting potential mechanisms of action. Burst-SCS is an evidence-based paraesthesia free waveform utilised for neuropathic pain with a potentially different mechanistic action to tonic SCS. This study examines the dynamic biological changes of CSF at a cellular and proteome level after Burst-SCS. METHODS Patients with neuropathic pain selected for SCS had CSF sampled prior to implant of SCS and following 8 weeks of continuous Burst-SCS. Baseline and 8-week pain scores with demographics were recorded. T cell frequencies were analysed by flow cytometry, proteome analysis was performed using mass spectrometry and secreted cytokines, chemokines and neurotrophins were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS 4 patients (2 females, 2 males) with a mean age of 51 years (+/-SEM 2.74, SD 5.48) achieved a reduction in pain of >50% following 8 weeks of Burst-SCS. Analysis of the CSF proteome indicated a significant alteration in protein expression most related to synapse assembly and immune regulators. There was significantly lower expression of the proteins: growth hormone A1 (PRL), somatostatin (SST), nucleobindin-2 (NUCB2), Calbindin (CALB1), acyl-CoA binding protein (DBI), proSAAS (PCSK1N), endothelin-3 (END3) and cholecystokinin (CCK) after Burst-SCS. The concentrations of secreted chemokines and cytokines and the frequencies of T cells were not significantly changed following Burst-SCS. CONCLUSION This study characterised the alteration in the CSF proteome in response to burst SCS in vivo. Functional analysis indicated that the alterations in the CSF proteome is predominately linked to synapse assembly and immune effectors. Individual protein analysis also suggests potential supraspinal mechanisms.
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Affiliation(s)
- Jonathan Royds
- Department of Pain Medicine, St. James Hospital, Dublin and School of Medicine, Trinity College Dublin, Ireland.
| | - Melissa J Conroy
- Department of Surgery, Trinity Translational Medicine Institute, St. James's Hospital and Trinity College Dublin, Dublin 8, Ireland
| | - Margaret R Dunne
- Department of Surgery, Trinity Translational Medicine Institute, St. James's Hospital and Trinity College Dublin, Dublin 8, Ireland
| | - Hilary Cassidy
- Systems Biology Ireland, School of Medicine, University College Dublin, Dublin 4, Ireland
| | - David Matallanas
- Systems Biology Ireland, School of Medicine, University College Dublin, Dublin 4, Ireland
| | - Joanne Lysaght
- Department of Surgery, Trinity Translational Medicine Institute, St. James's Hospital and Trinity College Dublin, Dublin 8, Ireland
| | - Connail McCrory
- Department of Pain Medicine, St. James Hospital, Dublin and School of Medicine, Trinity College Dublin, Ireland
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Mack SM, Gomes I, Devi LA. Neuropeptide PEN and Its Receptor GPR83: Distribution, Signaling, and Regulation. ACS Chem Neurosci 2019; 10:1884-1891. [PMID: 30726666 DOI: 10.1021/acschemneuro.8b00559] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Neuropeptides are chemical messengers that act to regulate a number of physiological processes, including feeding, reward, pain, and memory, among others. PEN is one of the most abundant hypothalamic neuropeptides; however, until recently, its target receptor remained unknown. In this Review, we summarize recent developments in research focusing on PEN and its receptor GPR83. We describe the studies leading to the deorphanization of GPR83 as the receptor for PEN. We also describe the signaling mediated by the PEN-GPR83 system, as well as the physiological roles in which PEN-GPR83 has been implicated. As studies have suggested a role for the PEN-GPR83 system in food intake and body weight regulation, as well as in drug addiction and reward disorders, a thorough understanding of this novel neuropeptide-receptor system will help identify novel therapeutic targets to treat pathophysiological conditions involving PEN-GPR83.
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Affiliation(s)
- Seshat M. Mack
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
| | - Ivone Gomes
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
| | - Lakshmi A. Devi
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
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Abstract
The organs require oxygen and other types of nutrients (amino acids, sugars, and lipids) to function, the heart consuming large amounts of fatty acids for oxidation and adenosine triphosphate (ATP) generation.
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Khoonsari PE, Musunri S, Herman S, Svensson CI, Tanum L, Gordh T, Kultima K. Systematic analysis of the cerebrospinal fluid proteome of fibromyalgia patients. J Proteomics 2019; 190:35-43. [DOI: 10.1016/j.jprot.2018.04.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 03/28/2018] [Accepted: 04/05/2018] [Indexed: 01/08/2023]
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Lueptow LM, Devi LA, Fakira AK. Targeting the Recently Deorphanized Receptor GPR83 for the Treatment of Immunological, Neuroendocrine and Neuropsychiatric Disorders. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2018; 159:1-25. [PMID: 30340784 DOI: 10.1016/bs.pmbts.2018.07.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
G-protein coupled receptors (GPCRs) are a superfamily of receptors responsible for initiation of a myriad of intracellular signaling cascades. Currently, GPCRs represent approximately 34% of marketed pharmaceuticals, a large portion of which have no known endogenous ligand. These orphan GPCRs represent a large pool of novel targets for drug development. Very recently, the neuropeptide PEN, derived from the proteolytic processing of the precursor proSAAS, has been identified as a selective, high-affinity endogenous ligand for the orphan receptor, GPR83. GPR83 is highly expressed in the brain, spleen and thymus, indicating that this receptor may be a target to treat neurological and immune disorders. In the brain GPR83 is expressed in regions involved in the reward pathway, stress/anxiety responses, learning and memory and metabolism. However, the cell type specific expression of GPR83 in these regions has only recently begun to be characterized. In the immune system, GPR83 expression is regulated by Foxp3 in T-regulatory cells that are involved in autoimmune responses. Moreover, in the brain this receptor is regulated by interactions with other GPCRs, such as the recently deorphanized receptor, GPR171, and other hypothalamic receptors such as MC4R and GHSR. The following review will summarize the properties of GPR83 and highlight its known and potential significance in health and disease, as well as its promise as a novel target for drug development.
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Affiliation(s)
- Lindsay M Lueptow
- Department of Pharmacological Sciences, Freidman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Lakshmi A Devi
- Department of Pharmacological Sciences, Freidman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States.
| | - Amanda K Fakira
- Department of Pharmacological Sciences, Freidman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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Checco JW, Zhang G, Yuan WD, Yu K, Yin SY, Roberts-Galbraith RH, Yau PM, Romanova EV, Jing J, Sweedler JV. Molecular and Physiological Characterization of a Receptor for d-Amino Acid-Containing Neuropeptides. ACS Chem Biol 2018. [PMID: 29543428 PMCID: PMC5962930 DOI: 10.1021/acschembio.8b00167] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
![]()
Neuropeptides
in several animals undergo an unusual post-translational
modification, the isomerization of an amino acid residue from the l-stereoisomer to the d-stereoisomer. The resulting d-amino acid-containing peptide (DAACP) often displays biological
activity higher than that of its all-l-residue analogue,
with the d-residue being critical for function in many cases.
However, little is known about the full physiological roles played
by DAACPs, and few studies have examined the interaction of DAACPs
with their cognate receptors. Here, we characterized the signaling
of several DAACPs derived from a single neuropeptide prohormone, the Aplysia californica achatin-like neuropeptide precursor
(apALNP), at their putative receptor, the achatin-like neuropeptide
receptor (apALNR). We first used quantitative polymerase chain reaction
and in situ hybridization experiments to demonstrate
receptor (apALNR) expression throughout the central
nervous system; on the basis of the expression pattern, we identified
novel physiological functions that may be mediated by apALNR. To gain
insight into ligand signaling through apALNR, we created a library
of native and non-native neuropeptide analogues derived from apALNP
(the neuropeptide prohormone) and evaluated them for activity in cells
co-transfected with apALNR and the promiscuous Gα
subunit Gα-16. Several of these neuropeptide
analogues were also evaluated for their ability to induce circuit
activity in a well-defined neural network associated with feeding
behavior in intact ganglia from Aplysia. Our results
reveal the specificity of apALNR and provide strong evidence that
this receptor mediates diverse physiological functions throughout
the central nervous system. Finally, we show that some native apALNP-derived
DAACPs exhibit enhanced stability toward endogenous proteases, suggesting
that the d-residues in these DAACPs may increase the peptide
lifetime, in addition to influencing receptor specificity, in the
nervous system. Ultimately, these studies provide insight into signaling
at one of the few known DAACP-specific receptors and advance our understanding
of the roles that l- to d-residue isomerization
play in neuropeptide signaling.
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Affiliation(s)
- James W. Checco
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Guo Zhang
- State Key Laboratory of Pharmaceutical Biotechnology, Collaborative Innovation Center of Chemistry for Life Sciences, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Advanced Institute for Life Sciences, School of Life Sciences, Nanjing University, Nanjing, China
| | - Wang-ding Yuan
- State Key Laboratory of Pharmaceutical Biotechnology, Collaborative Innovation Center of Chemistry for Life Sciences, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Advanced Institute for Life Sciences, School of Life Sciences, Nanjing University, Nanjing, China
| | - Ke Yu
- State Key Laboratory of Pharmaceutical Biotechnology, Collaborative Innovation Center of Chemistry for Life Sciences, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Advanced Institute for Life Sciences, School of Life Sciences, Nanjing University, Nanjing, China
| | - Si-yuan Yin
- State Key Laboratory of Pharmaceutical Biotechnology, Collaborative Innovation Center of Chemistry for Life Sciences, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Advanced Institute for Life Sciences, School of Life Sciences, Nanjing University, Nanjing, China
| | - Rachel H. Roberts-Galbraith
- Department of Cell and Developmental Biology, Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Peter M. Yau
- Roy J. Carver Biotechnology Center, Protein Sciences Facility, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Elena V. Romanova
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Jian Jing
- State Key Laboratory of Pharmaceutical Biotechnology, Collaborative Innovation Center of Chemistry for Life Sciences, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Advanced Institute for Life Sciences, School of Life Sciences, Nanjing University, Nanjing, China
| | - Jonathan V. Sweedler
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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Abstract
Neuropeptides are the largest class of intercellular signaling molecules, contributing to a wide variety of physiological processes. Neuropeptide receptors are therapeutic targets for a broad range of drugs, including medications to treat pain, addiction, sleep disorders, and nausea. In addition to >100 peptides with known functions, many peptides have been identified in mammalian brain for which the cognate receptors have not been identified. Similarly, dozens of "orphan" G protein-coupled receptors have been identified in the mammalian genome. While it would seem straightforward to match the orphan peptides and receptors, this is not always easily accomplished. In this review we focus on peptides named PEN and big LEN, which are among the most abundant neuropeptides in mouse brain, and their recently identified receptors: GPR83 and GPR171. These receptors are co-expressed in some brain regions and are able to interact. Because PEN and big LEN are produced from the same precursor protein and co-secreted, the interaction of GPR83 and GPR171 is physiologically relevant. In addition to interactions of these two peptides/receptors, PEN and LEN are co-localized with neuropeptide Y and Agouti-related peptide in neurons that regulate feeding. In this review, using these peptide receptors as an example, we highlight the multiple modes of regulation of receptors and present the emerging view that neuropeptides function combinatorially to generate a network of signaling messages. The complexity of neuropeptides, receptors, and their signaling pathways is important to consider both in the initial deorphanization of peptides and receptors, and in the subsequent development of therapeutic applications.
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Affiliation(s)
- Lloyd D Fricker
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, United States
| | - Lakshmi A Devi
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States.
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Greenwood MP, Greenwood M, Romanova EV, Mecawi AS, Paterson A, Sarenac O, Japundžić-Žigon N, Antunes-Rodrigues J, Paton JFR, Sweedler JV, Murphy D. The effects of aging on biosynthetic processes in the rat hypothalamic osmoregulatory neuroendocrine system. Neurobiol Aging 2018; 65:178-191. [PMID: 29494864 PMCID: PMC5878011 DOI: 10.1016/j.neurobiolaging.2018.01.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 07/11/2017] [Accepted: 01/16/2018] [Indexed: 11/21/2022]
Abstract
Elderly people exhibit a diminished capacity to cope with osmotic challenges such as dehydration. We have undertaken a detailed molecular analysis of arginine vasopressin (AVP) biosynthetic processes in the supraoptic nucleus (SON) of the hypothalamus and secretory activity in the posterior pituitary of adult (3 months) and aged (18 months) rats, to provide a comprehensive analysis of age-associated changes to the AVP system. By matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis, we identified differences in pituitary peptides, including AVP, in adult and aged rats under both basal and dehydrated states. In the SON, increased Avp gene transcription, coincided with reduced Avp promoter methylation in aged rats. Based on transcriptome data, we have previously characterized a number of novel dehydration-induced regulatory factors involved in the response of the SON to osmotic cues. We found that some of these increase in expression with age, while dehydration-induced expression of these genes in the SON was attenuated in aged rats. In summary, we show that aging alters the rat AVP system at the genome, transcriptome, and peptidome levels. These alterations however did not affect circulating levels of AVP in basal or dehydrated states.
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Affiliation(s)
| | | | - Elena V Romanova
- Department of Chemistry and the Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Andre S Mecawi
- School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil; Department of Physiology, University of Malaya, Kuala Lumpur, Malaysia; Department of Physiological Sciences, Institute of Biological and Health Sciênces, Federal Rural University of Rio de Janeiro, Seropedica, Brazil
| | - Alex Paterson
- School of Clinical Sciences, University of Bristol, Bristol, England
| | - Olivera Sarenac
- School of Clinical Sciences, University of Bristol, Bristol, England; Institute of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Nina Japundžić-Žigon
- Institute of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | | | - Julian F R Paton
- School of Physiology and Pharmacology, University of Bristol, Bristol, England
| | - Jonathan V Sweedler
- Department of Chemistry and the Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - David Murphy
- School of Clinical Sciences, University of Bristol, Bristol, England; Department of Physiology, University of Malaya, Kuala Lumpur, Malaysia
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The neural chaperone proSAAS blocks α-synuclein fibrillation and neurotoxicity. Proc Natl Acad Sci U S A 2016; 113:E4708-15. [PMID: 27457957 DOI: 10.1073/pnas.1601091113] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Emerging evidence strongly suggests that chaperone proteins are cytoprotective in neurodegenerative proteinopathies involving protein aggregation; for example, in the accumulation of aggregated α-synuclein into the Lewy bodies present in Parkinson's disease. Of the various chaperones known to be associated with neurodegenerative disease, the small secretory chaperone known as proSAAS (named after four residues in the amino terminal region) has many attractive properties. We show here that proSAAS, widely expressed in neurons throughout the brain, is associated with aggregated synuclein deposits in the substantia nigra of patients with Parkinson's disease. Recombinant proSAAS potently inhibits the fibrillation of α-synuclein in an in vitro assay; residues 158-180, containing a largely conserved element, are critical to this bioactivity. ProSAAS also exhibits a neuroprotective function; proSAAS-encoding lentivirus blocks α-synuclein-induced cytotoxicity in primary cultures of nigral dopaminergic neurons, and recombinant proSAAS blocks α-synuclein-induced cytotoxicity in SH-SY5Y cells. Four independent proteomics studies have previously identified proSAAS as a potential cerebrospinal fluid biomarker in various neurodegenerative diseases. Coupled with prior work showing that proSAAS blocks β-amyloid aggregation into fibrils, this study supports the idea that neuronal proSAAS plays an important role in proteostatic processes. ProSAAS thus represents a possible therapeutic target in neurodegenerative disease.
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Gomes I, Bobeck EN, Margolis EB, Gupta A, Sierra S, Fakira AK, Fujita W, Müller TD, Müller A, Tschöp MH, Kleinau G, Fricker LD, Devi LA. Identification of GPR83 as the receptor for the neuroendocrine peptide PEN. Sci Signal 2016; 9:ra43. [PMID: 27117253 DOI: 10.1126/scisignal.aad0694] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
PEN is an abundant peptide in the brain that has been implicated in the regulation of feeding. We identified a receptor for PEN in mouse hypothalamus and Neuro2A cells. PEN bound to and activated GPR83, a G protein (heterotrimeric guanine nucleotide)-binding protein)-coupled receptor (GPCR). Reduction of GPR83 expression in mouse brain and Neuro2A cells reduced PEN binding and signaling, consistent with GPR83 functioning as the major receptor for PEN. In some brain regions, GPR83 colocalized with GPR171, a GPCR that binds the neuropeptide bigLEN, another neuropeptide that is involved in feeding and is generated from the same precursor protein as is PEN. Coexpression of these two receptors in cell lines altered the signaling properties of each receptor, suggesting a functional interaction. Our data established PEN as a neuropeptide that binds GPR83 and suggested that these two ligand-receptor systems-PEN-GPR83 and bigLEN-GPR171-may be functionally coupled in the regulation of feeding.
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Affiliation(s)
- Ivone Gomes
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Erin N Bobeck
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Elyssa B Margolis
- Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Achla Gupta
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Salvador Sierra
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Amanda K Fakira
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Wakako Fujita
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Timo D Müller
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany. Division of Metabolic Diseases, Department of Medicine, Technische Universität München, 80333 Munich, Germany
| | - Anne Müller
- Institut für Experimentelle Pädiatrische Endokrinologie, Charité-Universitätsmedizin, 13125 Berlin, Germany
| | - Matthias H Tschöp
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany. Division of Metabolic Diseases, Department of Medicine, Technische Universität München, 80333 Munich, Germany
| | - Gunnar Kleinau
- Institut für Experimentelle Pädiatrische Endokrinologie, Charité-Universitätsmedizin, 13125 Berlin, Germany
| | - Lloyd D Fricker
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Lakshmi A Devi
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA. Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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16
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Ramos-Molina B, Martin MG, Lindberg I. PCSK1 Variants and Human Obesity. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2016; 140:47-74. [PMID: 27288825 DOI: 10.1016/bs.pmbts.2015.12.001] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PCSK1, encoding prohormone convertase 1/3 (PC1/3), was one of the first genes linked to monogenic early-onset obesity. PC1/3 is a protease involved in the biosynthetic processing of a variety of neuropeptides and prohormones in endocrine tissues. PC1/3 activity is essential for the activating cleavage of many peptide hormone precursors implicated in the regulation of food ingestion, glucose homeostasis, and energy homeostasis, for example, proopiomelanocortin, proinsulin, proglucagon, and proghrelin. A large number of genome-wide association studies in a variety of different populations have now firmly established a link between three PCSK1 polymorphisms frequent in the population and increased risk of obesity. Human subjects with PC1/3 deficiency, a rare autosomal-recessive disorder caused by the presence of loss-of-function mutations in both alleles, are obese and display a complex set of endocrinopathies. Increasing numbers of genetic diagnoses of infants with persistent diarrhea has recently led to the finding of many novel PCSK1 mutations. PCSK1-deficient infants experience severe intestinal malabsorption during the first years of life, requiring controlled nutrition; these children then become hyperphagic, with associated obesity. The biochemical characterization of novel loss-of-function PCSK1 mutations has resulted in the discovery of new pathological mechanisms affecting the cell biology of the endocrine cell beyond simple loss of enzyme activity, for example, dominant-negative effects of certain mutants on wild-type PC1/3 protein, and activation of the cellular unfolded protein response by endoplasmic reticulum-retained mutants. A better understanding of these molecular and cellular pathologies may illuminate possible treatments for the complex endocrinopathy of PCSK1 deficiency, including obesity.
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Affiliation(s)
- B Ramos-Molina
- Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - M G Martin
- Department of Pediatrics, Division of Gastroenterology and Nutrition, Mattel Children's Hospital and the David Geffen School of Medicine, Los Angeles, CA, United States of America
| | - I Lindberg
- Department of Anatomy and Neurobiology, University of Maryland, Baltimore, MD, United States of America.
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17
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Wardman JH, Fricker LD. ProSAAS-derived peptides are differentially processed and sorted in mouse brain and AtT-20 cells. PLoS One 2014; 9:e104232. [PMID: 25148519 PMCID: PMC4141687 DOI: 10.1371/journal.pone.0104232] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 07/08/2014] [Indexed: 11/18/2022] Open
Abstract
ProSAAS is the precursor for some of the most abundant peptides found in mouse brain and other tissues, including peptides named SAAS, PEN, and LEN. Both SAAS and LEN are found in big and little forms due to differential processing. Initial processing of proSAAS is mediated by furin (and/or furin-like enzymes) and carboxypeptidase D, while the smaller forms are generated by secretory granule prohormone convertases and carboxypeptidase E. In mouse hypothalamus, PEN and big LEN colocalize with neuropeptide Y. In the present study, little LEN and SAAS were detected in mouse hypothalamus but not in cell bodies of neuropeptide Y-expressing neurons. PEN and big LEN show substantial colocalization in hypothalamus, but big LEN and little LEN do not. An antiserum to SAAS that detects both big and little forms of this peptide did not show substantial colocalization with PEN or big LEN. To further study this, the AtT-20 cells mouse pituitary corticotrophic cell line was transfected with rat proSAAS and the distribution of peptides examined. As found in mouse hypothalamus, only some of the proSAAS-derived peptides colocalized with each other in AtT-20 cells. The two sites within proSAAS that are known to be efficiently cleaved by furin were altered by site-directed mutagenesis to convert the P4 Arg into Lys; this change converts the sequences from furin consensus sites into prohormone convertase consensus sites. Upon expression of the mutated form of proSAAS in AtT-20 cells, there was significantly more colocalization of proSAAS-derived peptides PEN and SAAS. Taken together, these results indicate that proSAAS is initially cleaved in the Golgi or trans-Golgi network by furin and/or furin-like enzymes and the resulting fragments are sorted into distinct vesicles and further processed by additional enzymes into the mature peptides.
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Affiliation(s)
- Jonathan H. Wardman
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Lloyd D. Fricker
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, United States of America
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
- * E-mail:
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18
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Southey BR, Lee JE, Zamdborg L, Atkins N, Mitchell JW, Li M, Gillette MU, Kelleher NL, Sweedler JV. Comparing label-free quantitative peptidomics approaches to characterize diurnal variation of peptides in the rat suprachiasmatic nucleus. Anal Chem 2013; 86:443-52. [PMID: 24313826 PMCID: PMC3886391 DOI: 10.1021/ac4023378] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Mammalian
circadian rhythm is maintained by the suprachiasmatic nucleus (SCN)
via an intricate set of neuropeptides and other signaling molecules.
In this work, peptidomic analyses from two times of day were examined
to characterize variation in SCN peptides using three different label-free
quantitation approaches: spectral count, spectra index and SIEVE.
Of the 448 identified peptides, 207 peptides were analyzed by two
label-free methods, spectral count and spectral index. There were
24 peptides with significant (adjusted p-value <
0.01) differential peptide abundances between daytime and nighttime,
including multiple peptides derived from secretogranin II, cocaine
and amphetamine regulated transcript, and proprotein convertase subtilisin/kexin
type 1 inhibitor. Interestingly, more peptides were analyzable and
had significantly different abundances between the two time points
using the spectral count and spectral index methods than with a prior
analysis using the SIEVE method with the same data. The results of
this study reveal the importance of using the appropriate data analysis
approaches for label-free relative quantitation of peptides. The detection
of significant changes in so rich a set of neuropeptides reflects
the dynamic nature of the SCN and the number of influences such as
feeding behavior on circadian rhythm. Using spectral count and spectral
index, peptide level changes are correlated to time of day, suggesting
their key role in circadian function.
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Affiliation(s)
- Bruce R Southey
- Department of Animal Sciences, ‡Department of Chemistry, §Institute for Genomic Biology, ∥Neuroscience Program, ⊥Department of Cell and Developmental Biology, and ¶Beckman Institute, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
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GPR171 is a hypothalamic G protein-coupled receptor for BigLEN, a neuropeptide involved in feeding. Proc Natl Acad Sci U S A 2013; 110:16211-6. [PMID: 24043826 DOI: 10.1073/pnas.1312938110] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Multiple peptide systems, including neuropeptide Y, leptin, ghrelin, and others, are involved with the control of food intake and body weight. The peptide LENSSPQAPARRLLPP (BigLEN) has been proposed to act through an unknown receptor to regulate body weight. In the present study, we used a combination of ligand-binding and receptor-activity assays to characterize a Gαi/o protein-coupled receptor activated by BigLEN in the mouse hypothalamus and Neuro2A cells. We then selected orphan G protein-coupled receptors expressed in the hypothalamus and Neuro2A cells and tested each for activation by BigLEN. G protein-coupled receptor 171 (GPR171) is activated by BigLEN, but not by the C terminally truncated peptide LittleLEN. The four C-terminal amino acids of BigLEN are sufficient to bind and activate GPR171. Overexpression of GPR171 leads to an increase, and knockdown leads to a decrease, in binding and signaling by BigLEN and the C-terminal peptide. In the hypothalamus GPR171 expression complements the expression of BigLEN, and its level and activity are elevated in mice lacking BigLEN. In mice, shRNA-mediated knockdown of hypothalamic GPR171 leads to a decrease in BigLEN signaling and results in changes in food intake and metabolism. The combination of GPR171 shRNA together with neutralization of BigLEN peptide by antibody absorption nearly eliminates acute feeding in food-deprived mice. Taken together, these results demonstrate that GPR171 is the BigLEN receptor and that the BigLEN-GPR171 system plays an important role in regulating responses associated with feeding and metabolism in mice.
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20
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Dimatelis JJ, Russell VA, Stein DJ, Daniels WM. Effects of maternal separation and methamphetamine exposure on protein expression in the nucleus accumbens shell and core. Metab Brain Dis 2012; 27:363-75. [PMID: 22451087 DOI: 10.1007/s11011-012-9295-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Accepted: 03/15/2012] [Indexed: 12/14/2022]
Abstract
Early life adversity has been suggested to predispose an individual to later drug abuse. The core and shell sub-regions of the nucleus accumbens are differentially affected by both stressors and methamphetamine. This study aimed to characterize and quantify methamphetamine-induced protein expression in the shell and core of the nucleus accumbens in animals exposed to maternal separation during early development. Isobaric tagging (iTRAQ) which enables simultaneous identification and quantification of peptides with tandem mass spectrometry (MS/MS) was used. We found that maternal separation altered more proteins involved in structure and redox regulation in the shell than in the core of the nucleus accumbens, and that maternal separation and methamphetamine had differential effects on signaling proteins in the shell and core. Compared to maternal separation or methamphetamine alone, the maternal separation/methamphetamine combination altered more proteins involved in energy metabolism, redox regulatory processes and neurotrophic proteins. Methamphetamine treatment of rats subjected to maternal separation caused a reduction of cytoskeletal proteins in the shell and altered cytoskeletal, signaling, energy metabolism and redox proteins in the core. Comparison of maternal separation/methamphetamine to methamphetamine alone resulted in decreased cytoskeletal proteins in both the shell and core and increased neurotrophic proteins in the core. This study confirms that both early life stress and methamphetamine differentially affect the shell and core of the nucleus accumbens and demonstrates that the combination of early life adversity and later methamphetamine use results in more proteins being affected in the nucleus accumbens than either treatment alone.
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Affiliation(s)
- J J Dimatelis
- Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Observatory, 7925 Cape Town, South Africa.
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22
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Murphy D, Konopacka A, Hindmarch C, Paton JFR, Sweedler JV, Gillette MU, Ueta Y, Grinevich V, Lozic M, Japundzic-Zigon N. The hypothalamic-neurohypophyseal system: from genome to physiology. J Neuroendocrinol 2012; 24:539-53. [PMID: 22448850 PMCID: PMC3315060 DOI: 10.1111/j.1365-2826.2011.02241.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The elucidation of the genomes of a large number of mammalian species has produced a huge amount of data on which to base physiological studies. These endeavours have also produced surprises, not least of which has been the revelation that the number of protein coding genes needed to make a mammal is only 22 333 (give or take). However, this small number belies an unanticipated complexity that has only recently been revealed as a result of genomic studies. This complexity is evident at a number of levels: (i) cis-regulatory sequences; (ii) noncoding and antisense mRNAs, most of which have no known function; (iii) alternative splicing that results in the generation of multiple, subtly different mature mRNAs from the precursor transcript encoded by a single gene; and (iv) post-translational processing and modification. In this review, we examine the steps being taken to decipher genome complexity in the context of gene expression, regulation and function in the hypothalamic-neurohypophyseal system (HNS). Five unique stories explain: (i) the use of transcriptomics to identify genes involved in the response to physiological (dehydration) and pathological (hypertension) cues; (ii) the use of mass spectrometry for single-cell level identification of biological active peptides in the HNS, and to measure in vitro release; (iii) the use of transgenic lines that express fusion transgenes enabling (by cross-breeding) the generation of double transgenic lines that can be used to study vasopressin (AVP) and oxytocin (OXT) neurones in the HNS, as well as their neuroanatomy, electrophysiology and activation upon exposure to any given stimulus; (iv) the use of viral vectors to demonstrate that somato-dendritically released AVP plays an important role in cardiovascular homeostasis by binding to V1a receptors on local somata and dendrites; and (v) the use of virally-mediated optogenetics to dissect the role of OXT and AVP in the modulation of a wide variety of behaviours.
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Affiliation(s)
- D Murphy
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol, Bristol, UK.
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Wardman JH, Berezniuk I, Di S, Tasker JG, Fricker LD. ProSAAS-derived peptides are colocalized with neuropeptide Y and function as neuropeptides in the regulation of food intake. PLoS One 2011; 6:e28152. [PMID: 22164236 PMCID: PMC3229528 DOI: 10.1371/journal.pone.0028152] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Accepted: 11/02/2011] [Indexed: 11/28/2022] Open
Abstract
ProSAAS is the precursor of a number of peptides that have been proposed to function as neuropeptides. Because proSAAS mRNA is highly expressed in the arcuate nucleus of the hypothalamus, we examined the cellular localization of several proSAAS-derived peptides in the mouse hypothalamus and found that they generally colocalized with neuropeptide Y (NPY), but not α-melanocyte stimulating hormone. However, unlike proNPY mRNA, which is upregulated by food deprivation in the mediobasal hypothalamus, neither proSAAS mRNA nor proSAAS-derived peptides were significantly altered by 1–2 days of food deprivation in wild-type mice. Furthermore, while proSAAS mRNA levels in the mediobasal hypothalamus were significantly lower in Cpefat/fat mice as compared to wild-type littermates, proNPY mRNA levels in the mediobasal hypothalamus and in other subregions of the hypothalamus were not significantly different between wild-type and Cpefat/fat mice. Intracerebroventricular injections of antibodies to two proSAAS-derived peptides (big LEN and PEN) significantly reduced food intake in fasted mice, while injections of antibodies to two other proSAAS-derived peptides (little LEN and little SAAS) did not. Whole-cell patch clamp recordings of parvocellular neurons in the hypothalamic paraventricular nucleus, a target of arcuate NPY projections, showed that big LEN produced a rapid and reversible inhibition of synaptic glutamate release that was spike independent and abolished by blocking postsynaptic G protein activity, suggesting the involvement of a postsynaptic G protein-coupled receptor and the release of a retrograde synaptic messenger. Taken together with previous studies, these findings support a role for proSAAS-derived peptides such as big LEN as neuropeptides regulating food intake.
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Affiliation(s)
- Jonathan H. Wardman
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, New York, United States of America
| | - Iryna Berezniuk
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, New York, United States of America
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, New York, United States of America
| | - Shi Di
- Department of Cell and Molecular Biology, Tulane University, New Orleans, Louisiana, United States of America
| | - Jeffrey G. Tasker
- Department of Cell and Molecular Biology, Tulane University, New Orleans, Louisiana, United States of America
- Neuroscience Program, Tulane University, New Orleans, Louisiana, United States of America
| | - Lloyd D. Fricker
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, New York, United States of America
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, New York, United States of America
- * E-mail:
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25
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Atkins N, Mitchell JW, Romanova EV, Morgan DJ, Cominski TP, Ecker JL, Pintar JE, Sweedler JV, Gillette MU. Circadian integration of glutamatergic signals by little SAAS in novel suprachiasmatic circuits. PLoS One 2010; 5:e12612. [PMID: 20830308 PMCID: PMC2935382 DOI: 10.1371/journal.pone.0012612] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Accepted: 08/03/2010] [Indexed: 12/03/2022] Open
Abstract
Background Neuropeptides are critical integrative elements within the central circadian clock in the suprachiasmatic nucleus (SCN), where they mediate both cell-to-cell synchronization and phase adjustments that cause light entrainment. Forward peptidomics identified little SAAS, derived from the proSAAS prohormone, among novel SCN peptides, but its role in the SCN is poorly understood. Methodology/Principal Findings Little SAAS localization and co-expression with established SCN neuropeptides were evaluated by immunohistochemistry using highly specific antisera and stereological analysis. Functional context was assessed relative to c-FOS induction in light-stimulated animals and on neuronal circadian rhythms in glutamate-stimulated brain slices. We found that little SAAS-expressing neurons comprise the third most abundant neuropeptidergic class (16.4%) with unusual functional circuit contexts. Little SAAS is localized within the densely retinorecipient central SCN of both rat and mouse, but not the retinohypothalamic tract (RHT). Some little SAAS colocalizes with vasoactive intestinal polypeptide (VIP) or gastrin-releasing peptide (GRP), known mediators of light signals, but not arginine vasopressin (AVP). Nearly 50% of little SAAS neurons express c-FOS in response to light exposure in early night. Blockade of signals that relay light information, via NMDA receptors or VIP- and GRP-cognate receptors, has no effect on phase delays of circadian rhythms induced by little SAAS. Conclusions/Significance Little SAAS relays signals downstream of light/glutamatergic signaling from eye to SCN, and independent of VIP and GRP action. These findings suggest that little SAAS forms a third SCN neuropeptidergic system, processing light information and activating phase-shifts within novel circuits of the central circadian clock.
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Affiliation(s)
- Norman Atkins
- Neuroscience Program, University of Illinois, Urbana, Illinois, United States of America
| | - Jennifer W. Mitchell
- Department of Cell and Developmental Biology, University of Illinois, Urbana, Illinois, United States of America
| | - Elena V. Romanova
- Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana, Illinois, United States of America
| | - Daniel J. Morgan
- Department of Cell Biology and Neuroscience, University of Medicine and Dentistry of New Jersey, Newark, New Jersey, United States of America
| | - Tara P. Cominski
- Department of Cell Biology and Neuroscience, University of Medicine and Dentistry of New Jersey, Newark, New Jersey, United States of America
| | - Jennifer L. Ecker
- Department of Biology, The Johns Hopkins University, Baltimore, Maryland, United States of America
| | - John E. Pintar
- Department of Cell Biology and Neuroscience, University of Medicine and Dentistry of New Jersey, Newark, New Jersey, United States of America
| | - Jonathan V. Sweedler
- Neuroscience Program, University of Illinois, Urbana, Illinois, United States of America
- Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana, Illinois, United States of America
- Department of Chemistry, University of Illinois, Urbana, Illinois, United States of America
| | - Martha U. Gillette
- Neuroscience Program, University of Illinois, Urbana, Illinois, United States of America
- Department of Cell and Developmental Biology, University of Illinois, Urbana, Illinois, United States of America
- Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana, Illinois, United States of America
- * E-mail:
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26
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Morgan DJ, Wei S, Gomes I, Czyzyk T, Mzhavia N, Pan H, Devi LA, Fricker LD, Pintar JE. The propeptide precursor proSAAS is involved in fetal neuropeptide processing and body weight regulation. J Neurochem 2010; 113:1275-84. [PMID: 20367757 DOI: 10.1111/j.1471-4159.2010.06706.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Mice with a targeted mutation in proSAAS have been generated to investigate whether peptides derived from this precursor could function as an inhibitor of prohormone convertase 1/3 (PC1/3) in vivo as well as to determine any alternate roles for proSAAS in nervous and endocrine tissues. Fetal mice lacking proSAAS exhibit complete, adult-like processing of prodynorphin in the prenatal brain instead of the incomplete processing seen in the brains of wild-type fetal mice where inhibitory proSAAS intermediates are transiently accumulated. This study provides evidence that proSAAS is directly involved in the prenatal regulation of neuropeptide processing in vivo. However, adult mice lacking proSAAS have normal levels of all peptides detected using a peptidomics approach, suggesting that PC1/3 activity is not affected by the absence of proSAAS in adult mice. ProSAAS knockout mice exhibit decreased locomotion and a male-specific 10-15% decrease in body weight, but maintain normal fasting blood glucose levels and are able to efficiently clear glucose from the blood in response to a glucose challenge. This work suggests that proSAAS-derived peptides can inhibit PC1/3 in embryonic brain, but in the adult brain proSAAS peptides may function as neuropeptides that regulate body weight and potentially other behaviors.
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Affiliation(s)
- Daniel J Morgan
- Department of Neuroscience and Cell Biology, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA
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27
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Watson E, Fargali S, Okamoto H, Sadahiro M, Gordon RE, Chakraborty T, Sleeman MW, Salton SR. Analysis of knockout mice suggests a role for VGF in the control of fat storage and energy expenditure. BMC PHYSIOLOGY 2009; 9:19. [PMID: 19863797 PMCID: PMC2774661 DOI: 10.1186/1472-6793-9-19] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Accepted: 10/28/2009] [Indexed: 11/29/2022]
Abstract
Background Previous studies of mixed background mice have demonstrated that targeted deletion of Vgf produces a lean, hypermetabolic mouse that is resistant to diet-, lesion-, and genetically-induced obesity. To investigate potential mechanism(s) and site(s) of action of VGF, a neuronal and endocrine secreted protein and neuropeptide precursor, we further analyzed the metabolic phenotypes of two independent VGF knockout lines on C57Bl6 backgrounds. Results Unlike hyperactive VGF knockout mice on a mixed C57Bl6-129/SvJ background, homozygous mutant mice on a C57Bl6 background were hypermetabolic with similar locomotor activity levels to Vgf+/Vgf+ mice, during day and night cycles, indicating that mechanism(s) other than hyperactivity were responsible for their increased energy expenditure. In Vgf-/Vgf- knockout mice, morphological analysis of brown and white adipose tissues (BAT and WAT) indicated decreased fat storage in both tissues, and decreased adipocyte perimeter and area in WAT. Changes in gene expression measured by real-time RT-PCR were consistent with increased fatty acid oxidation and uptake in BAT, and increased lipolysis, decreased lipogenesis, and brown adipocyte differentiation in WAT, suggesting that increased sympathetic nervous system activity in Vgf-/Vgf- mice may be associated with or responsible for alterations in energy expenditure and fat storage. In addition, uncoupling protein 1 (UCP1) and UCP2 protein levels, mitochondrial number, and mitochondrial cristae density were upregulated in Vgf-/Vgf- BAT. Using immunohistochemical and histochemical techniques, we detected VGF in nerve fibers innervating BAT and Vgf promoter-driven reporter expression in cervical and thoracic spinal ganglia that project to and innervate the chest wall and tissues including BAT. Moreover, VGF peptide levels were quantified by radioimmunoassay in BAT, and were found to be down-regulated by a high fat diet. Lastly, despite being hypermetabolic, VGF knockout mice were cold intolerant. Conclusion We propose that VGF and/or VGF-derived peptides modulate sympathetic outflow pathways to regulate fat storage and energy expenditure.
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Affiliation(s)
- Elizabeth Watson
- Department of Neuroscience, Mount Sinai School of Medicine, New York, NY, USA.
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28
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Lee JC, Hook V. Proteolytic fragments of chromogranins A and B represent major soluble components of chromaffin granules, illustrated by two-dimensional proteomics with NH(2)-terminal Edman peptide sequencing and MALDI-TOF MS. Biochemistry 2009; 48:5254-62. [PMID: 19405523 DOI: 10.1021/bi9002953] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Neuroendocrine chromaffin granules of adrenal medulla represent regulated secretory vesicles that secrete neuropeptides and catecholamines which mediate cell-cell communication for physiological functions. This study addressed the identification of the major proteins in these secretory vesicles that provide dynamic storage and secretion of bioactive molecules. Proteins of the soluble compartment of the vesicles were separated by two-dimensional gels and subjected to NH(2)-terminal Edman sequencing for identification and determination of NH(2)-termini. Results showed that proteolytic fragments of chromogranin A (CgA) and chromogranin B (CgB) represent the major proteins of these secretory vesicles. These fragments resulted from cleavage of their respective precursor proteins at dibasic and monobasic sites, which is consistent with the known cleavage specificities of prohormone processing enzymes. MALDI-TOF MS analyses of protein spots similar in molecular weight that possessed a range of pI values were represented by molecular forms of CgA and CgB proteins. These findings indicate the high prevalence of endogenous CgA and CgB proteolytic fragments that function in chromaffin secretory vesicles for release of bioactive molecules for cell-cell communication.
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Affiliation(s)
- Jean C Lee
- Department of Medicine, University of California at San Diego, La Jolla, California 92093, USA
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29
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Zhang X, Che FY, Berezniuk I, Sonmez K, Toll L, Fricker LD. Peptidomics of Cpe(fat/fat) mouse brain regions: implications for neuropeptide processing. J Neurochem 2008; 107:1596-613. [PMID: 19014391 DOI: 10.1111/j.1471-4159.2008.05722.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Quantitative peptidomics was used to compare levels of peptides in wild type (WT) and Cpe(fat/fat) mice, which lack carboxypeptidase E (CPE) activity because of a point mutation. Six different brain regions were analyzed: amygdala, hippocampus, hypothalamus, prefrontal cortex, striatum, and thalamus. Altogether, 111 neuropeptides or other peptides derived from secretory pathway proteins were identified in WT mouse brain extracts by tandem mass spectrometry, and another 47 peptides were tentatively identified based on mass and other criteria. Most secretory pathway peptides were much lower in Cpe(fat/fat) mouse brain, relative to WT mouse brain, indicating that CPE plays a major role in their biosynthesis. Other peptides were only partially reduced in the Cpe(fat/fat) mice, indicating that another enzyme (presumably carboxypeptidase D) contributes to their biosynthesis. Approximately 10% of the secretory pathway peptides were present in the Cpe(fat/fat) mouse brain at levels similar to those in WT mouse brain. Many peptides were greatly elevated in the Cpe(fat/fat) mice; these peptide processing intermediates with C-terminal Lys and/or Arg were generally not detectable in WT mice. Taken together, these results indicate that CPE contributes, either directly or indirectly, to the production of the majority of neuropeptides.
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Affiliation(s)
- Xin Zhang
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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30
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Gouraud SS, Heesom K, Yao ST, Qiu J, Paton JFR, Murphy D. Dehydration-induced proteome changes in the rat hypothalamo-neurohypophyseal system. Endocrinology 2007; 148:3041-52. [PMID: 17412804 DOI: 10.1210/en.2007-0181] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The hypothalamo-neurohypophyseal system (HNS) mediates neuroendocrine responses to dehydration through the action of the antidiuretic hormone vasopressin (VP). VP is synthesized as part of a prepropeptide in magnocellular neurons of the hypothalamic supraoptic nucleus (SON) and paraventricular nucleus. This precursor is processed during transport to axon terminals in the posterior pituitary gland, in which biologically active VP is stored until mobilized for secretion by electrical activity evoked by osmotic cues. During release, VP travels through the blood stream to specific receptor targets located in the kidney in which it increases the permeability of the collecting ducts to water, reducing the renal excretion of water, thus promoting water conservation. The HNS undergoes a dramatic function-related plasticity during dehydration. We hypothesize that alterations in steady-state protein levels might be partially responsible for this remodeling. We investigated dehydration-induced changes in the SON and pituitary neurointermediate lobe (NIL) proteomes using two-dimensional fluorescence difference gel electrophoresis. Seventy proteins were altered by dehydration, including 45 in the NIL and 25 in the SON. Using matrix-assisted laser desorption/ionization mass spectrometry, we identified six proteins in the NIL (four down, two up) and nine proteins in the SON (four up, five down) that are regulated as a consequence of chronic dehydration. Results for five of these proteins, namely Hsp1alpha (heat shock protein 1alpha), NAP22 (neuronal axonal membrane protein 22), GRP58 (58 kDa glucose regulated protein), calretinin, and ProSAAS (proprotein convertase subtilisin/kexin type 1 inhibitor), have been confirmed using independent methods such as semiquantitative Western blotting, two-dimensional Western blotting, enzyme-linked immunoassay, and immunohistochemistry. These proteins may have roles in regulating and effecting HNS remodeling.
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Affiliation(s)
- S S Gouraud
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, Department of Biochemistry Proteomics Facility, Bristol Heart Institute, University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol BS1 3NY, United Kingdom
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31
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Boonen K, Baggerman G, D'Hertog W, Husson SJ, Overbergh L, Mathieu C, Schoofs L. Neuropeptides of the islets of Langerhans: a peptidomics study. Gen Comp Endocrinol 2007; 152:231-41. [PMID: 17559849 DOI: 10.1016/j.ygcen.2007.05.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2006] [Revised: 04/19/2007] [Accepted: 05/01/2007] [Indexed: 10/23/2022]
Abstract
Neuropeptides from the endocrine pancreas (the islets of Langerhans) play an important role in the regulation of blood glucose levels. Therefore, our aim is to identify the "peptidome" (the in vivo peptide profile at a certain time) of the pancreatic islets, which is beneficial for medical progress related to the treatment of diabetes. So far, there are few neuropeptides isolated and sequenced from the endocrine pancreas and mainly in situ hybridisation and immunocytochemical techniques have been used to demonstrate the occurrence of peptides in the pancreas. These techniques do not allow for unequivocal identification of peptides. In contrary, mass spectrometry identifies peptides unambiguously. We have analysed the peptidome of the islets using peptidomics, i.e. a combination of liquid chromatography, mass spectrometry and bioinformatics. We are able to identify the peptidome of islets extracts. We not only confirm the presence of peptides with a well-known effect on blood glucose levels, but also identify new peptides, which are unknown to affect blood glucose levels.
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Affiliation(s)
- Kurt Boonen
- Laboratory of Developmental Physiology, Genomics and Proteomics, KU Leuven, Belgium.
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32
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Décaillot FM, Che FY, Fricker LD, Devi LA. Peptidomics of Cpefat/fat mouse hypothalamus and striatum: effect of chronic morphine administration. J Mol Neurosci 2007; 28:277-84. [PMID: 16691015 DOI: 10.1385/jmn:28:3:277] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2005] [Revised: 11/15/2005] [Accepted: 11/22/2005] [Indexed: 11/11/2022]
Abstract
Chronic morphine administration is known to affect several neuropeptide systems, and this could contribute to the behavioral effects of opiates. To quantitate global changes in neuropeptide levels upon chronic morphine administration, we took advantage of a method that allows selective isolation of neuropeptides from brains of mice lacking carboxypeptidase E (Cpefat/fat mice), a critical enzyme in the generation of many neuroendocrine peptides. We used a differential labeling procedure with stable isotopic tags and mass spectrometry to quantitate the relative changes in a number of hypothalamic and striatal peptides in Cpefat/fat mice chronically treated with morphine. A total of 27 distinct peptides were detected in hypothalamus and striatum. Of these, 27 were identified by mass spectrometry-based sequencing, 1 was tentatively identified by the mass and charge, and 9 were not identified. The identified peptides included fragments of proenkephalin, prothyrotropin-releasing hormone, secretogranin II, chromogranin Aand B, protachykinin B, provasopressin, promelanin concentrating hormone, and pro-SAAS. Upon morphine administration, although the levels of most of the peptides were unaltered (within a factor of 1.3 to 0.7 compared with saline control), the levels of a small number of peptides did show consistent changes (increased or decreased by 1.3-fold or more) in hypothalamus and/or striatum. Taken together, these results provide interesting insights into endogenous neuropeptide systems that are modulated by morphine and suggest further experiments to link candidate peptides with long-term effects of morphine.
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Affiliation(s)
- Fabien M Décaillot
- Department of Pharmacology and Biological Chemistry, Mount Sinai School of Medicine, New York, NY, USA
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33
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Dowell JA, Heyden WV, Li L. Rat Neuropeptidomics by LC−MS/MS and MALDI−FTMS: Enhanced Dissection and Extraction Techniques Coupled with 2D RP-RP HPLC. J Proteome Res 2006; 5:3368-75. [PMID: 17137338 DOI: 10.1021/pr0603452] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Recently developed sample preparation techniques employing microwave irradiation have enabled the comprehensive study of endogenous mammalian neuropeptides. These methods reduce interference from post-mortem protein degradation by deactivating proteases via heat denaturation. Alternatively, we have developed a protocol using cryostat dissection and a boiling extraction buffer to achieve a similar effect. This novel methodology greatly reduces post-mortem protein contamination and increases neuropeptide identification without the use of specialized equipment. In addition, a 2D HPLC scheme employing differential pH selectivity in the first and second dimensions has been used to enhance neuropeptidome coverage. By using our novel dissection protocol in tandem with 2D RP-RP HPLC, we were able to identify a total of 56 peptides from known neuropeptide precursors, including 17 previously unidentified peptides. The use of cryostat dissection and two-dimensional RP-RP HPLC enhances the detection of novel neuropeptides by deactivating proteases and reducing sample complexity.
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Affiliation(s)
- James A Dowell
- School of Pharmacy and Department of Chemistry, University of Wisconsin-Madison, 777 Highland Avenue, Madison, Wisconsin 53705-2222, USA
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34
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Chakraborty TR, Tkalych O, Nanno D, Garcia AL, Devi LA, Salton SRJ. Quantification of VGF- and pro-SAAS-derived peptides in endocrine tissues and the brain, and their regulation by diet and cold stress. Brain Res 2006; 1089:21-32. [PMID: 16631141 DOI: 10.1016/j.brainres.2006.02.124] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2005] [Revised: 12/13/2005] [Accepted: 02/26/2006] [Indexed: 11/23/2022]
Abstract
Two novel granin-like polypeptides, VGF and pro-SAAS, which are stored in and released from secretory vesicles and are expressed widely in nervous, endocrine, and neuroendocrine tissues, play roles in the regulation of body weight, feeding, and energy expenditure. Both VGF and pro-SAAS are cleaved into peptide fragments, several of which are biologically active. We utilized a highly sensitive and specific radioimmunoassay (RIA) to immunoreactive, pro-SAAS-derived PEN peptides, developed another against immunoreactive, VGF-derived AQEE30 peptides, and quantified these peptides in various mouse tissues and brain regions. Immunoreactive AQEE30 was most abundant in the pituitary, while brain levels were highest in hypothalamus, striatum, and frontal cortex. Immunoreactive PEN levels were highest in the pancreas and spinal cord, and in brain, PEN was most abundant in striatum, hippocampus, pons and medulla, and cortex. Since both peptides were expressed in hypothalamus, a region of the brain that controls feeding and energy expenditure, double label immunofluorescence studies were employed. These demonstrated that 42% of hypothalamic arcuate neurons coexpress VGF and SAAS peptides, and that the intracellular distributions of these peptides in arcuate neurons differed. By RIA, cold stress increased immunoreactive AQEE30 and PEN peptide levels in female but not male hypothalamus, while a high fat diet increased AQEE30 and PEN peptide levels in female but not male hippocampus. VGF and SAAS-derived peptides are therefore widely expressed in endocrine, neuroendocrine, and neural tissues, can be accurately quantified by RIA, and are differentially regulated in the brain by diet and cold stress.
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Affiliation(s)
- Tandra R Chakraborty
- Fishberg Department of Neuroscience, Mount Sinai School of Medicine, New York, NY 10029, USA
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35
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Fricker LD, Lim J, Pan H, Che FY. Peptidomics: identification and quantification of endogenous peptides in neuroendocrine tissues. MASS SPECTROMETRY REVIEWS 2006; 25:327-44. [PMID: 16404746 DOI: 10.1002/mas.20079] [Citation(s) in RCA: 170] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Neuropeptides perform a large variety of functions as intercellular signaling molecules. While most proteomic studies involve digestion of the proteins with trypsin or other proteases, peptidomics studies usually analyze the native peptide forms. Neuropeptides can be studied by using mass spectrometry for identification and quantitation. In many cases, mass spectrometry provides an understanding of the precise molecular form of the native peptide, including post-translational cleavages and other modifications. Quantitative peptidomics studies generally use differential isotopic tags to label two sets of extracted peptides, as done with proteomic studies, except that the Cys-based reagents typically used for quantitation of proteins are not suitable because most peptides lack Cys residues. Instead, a number of amine-specific labels have been created and some of these are useful for peptide quantitation by mass spectrometry. In this review, peptidomics techniques are discussed along with the major findings of many recent studies and future directions for the field.
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Affiliation(s)
- Lloyd D Fricker
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
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36
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Morgan DJ, Mzhavia N, Peng B, Pan H, Devi LA, Pintar JE. Embryonic gene expression and pro-protein processing of proSAAS during rodent development. J Neurochem 2005; 93:1454-62. [PMID: 15935061 DOI: 10.1111/j.1471-4159.2005.03138.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In vitro assays have demonstrated that peptides derived from the recently-identified proSAAS precursor inhibit prohormone convertase 1 (PC1) suggesting that this novel peptide may function as an endogenous inhibitor of PC1. To further understand the role of proSAAS in vivo, we have investigated the expression of proSAAS mRNA and processing of proSAAS during pre- and early postnatal rodent development. In situ hybridization showed that, by embryonic day 12.5 (e12.5) in the rat, proSAAS mRNA was present in essentially all differentiating neurons in the mantle layer of the myelencephalon, metencephalon, diencephalon, spinal cord and several sympathetic ganglia. During later stages of prenatal development, widespread proSAAS expression continues in post-mitotic neurons of both the CNS and PNS and begins in endocrine cells of the anterior and intermediate pituitary. Although proSAAS expression overlaps with PC1 in several regions, its overall expression pattern is significantly more extensive, suggesting that proSAAS may be multifunctional during development. Processed forms of proSAAS are present by at least mid-gestation with marked accumulation of two C-terminal forms, comprising the PC1 inhibitory fragment of proSAAS.
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Affiliation(s)
- Daniel J Morgan
- Department of Neuroscience and Cell Biology, University of Medicine and Dentistry of New Jersey, Piscataway, New Jersey, USA
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37
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Pan H, Nanno D, Che FY, Zhu X, Salton SR, Steiner DF, Fricker LD, Devi LA. Neuropeptide processing profile in mice lacking prohormone convertase-1. Biochemistry 2005; 44:4939-48. [PMID: 15779921 DOI: 10.1021/bi047852m] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Prohormone convertase 1 (PC1; also known as PC3) is believed to be responsible for the processing of many neuropeptide precursors. To look at the role PC1 plays in neuropeptide processing in brain and pituitary, we used radioimmunoassays (RIA) as well as quantitative peptidomic methods and examined changes in the levels of multiple neuropeptide products in PC1 knockout (KO) mice. The processing of proenkephalin was impaired in PC1 KO mouse brains with a decrease in the level of Met-Enkephalin immunoreactivity (ir-Met-Enk) and an accumulation of higher molecular weight processing intermediates containing ir-Met-Enk. Processing of the neuropeptide precursor VGF was also affected in PC1 KO mouse brains with a decrease in the level of an endogenous 3 kDa C-terminal peptide. In contrast, the processing of proSAAS into PEN was not altered in PC1 KO mouse brains. Quantitative mass spectrometry was used to analyze a number of peptides derived from proopiomelanocortin (POMC), provasopressin, prooxytocin, chromogranin A, chromogranin B, and secretogranin II. Among them, the levels of oxytocin and peptides derived from chromogranin A and B dramatically decreased in the PC1 KO mouse pituitaries, while the levels of peptides derived from proopiomelanocortin and provasopressin did not show substantial changes. In conclusion, these results support the notion that PC1 plays a key role in the processing of multiple neuroendocrine peptide precursors and also reveal the presence of a redundant system in the processing of a number of physiologically important bioactive peptides.
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Affiliation(s)
- Hui Pan
- Department of Pharmacology and Biological Chemistry, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York 10029, USA
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38
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Feng Y, Reznik SE, Fricker LD. ProSAAS and prohormone convertase 1 are broadly expressed during mouse development. Gene Expr Patterns 2005; 1:135-40. [PMID: 15018810 DOI: 10.1016/s1567-133x(02)00002-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2001] [Accepted: 01/03/2002] [Indexed: 11/18/2022]
Abstract
ProSAAS (encoded by mouse gene Pcsk1n) is a recently described neuroendocrine secretory pathway protein that is cleaved into smaller peptides that may function in cell-cell signalling. ProSAAS and its processing intermediates are also potent inhibitors of prohormone convertase 1 (PC1), which is encoded by mouse gene Pcsk1. In order to gain insight into the function of proSAAS, we have examined the distribution of several proSAAS-derived peptides and PC1 by immunohistochemistry throughout mouse development. The distribution patterns of both SAAS and PC1 are broad from E9 to E11, with some enrichment in neural tube-derived tissues. By E15, the expression of SAAS is largely restricted to neuroendocrine tissues known to produce bioactive peptides. In general, the expression pattern of PC1 overlaps with that of SAAS and other proSAAS-derived peptides, consistent with the hypothesis that proSAAS functions as an endogenous PC1 inhibitor.
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Affiliation(s)
- Yun Feng
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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39
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Che FY, Yuan Q, Kalinina E, Fricker LD. Peptidomics of Cpe fat/fat mouse hypothalamus: effect of food deprivation and exercise on peptide levels. J Biol Chem 2004; 280:4451-61. [PMID: 15572367 DOI: 10.1074/jbc.m411178200] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Carboxypeptidase E is a major enzyme in the biosynthesis of numerous neuroendocrine peptides. Previously, we developed a technique for the isolation of neuropeptide-processing intermediates from mice that lack carboxypeptidase E activity (Cpe fat/fat mice) due to a naturally occurring point mutation. In the present study, we used a differential labeling procedure with stable isotopic tags and mass spectrometry to quantitate the relative changes in a number of hypothalamic peptides in Cpe fat/fat mice in two different paradigms that each cause an approximately 10% decrease in body mass. One paradigm involved a 2-day fast under normal sedentary conditions (i.e. standard mouse cages); the other involved giving mice access to an exercise wheel for 4 weeks with free access to food. Approximately 50 peptides were detected in both studies, and over 80 peptides were detected in at least one of the two studies. Twenty-eight peptides were increased >50% by food deprivation, and some of these were increased by 2- to 3-fold. In contrast, only three peptides were increased >50% in the group with exercise wheels, and many peptides showed a slight 15-30% decrease upon exercise. Approximately one-half of the peptides detected in both studies were identified by tandem mass spectrometry. Peptides found to be elevated by food deprivation but not exercise included a number of fragments of proenkephalin, prothyrotropin-releasing hormone, secretogranin II, chromogranin B, and pro-SAAS. Taken together, the differential regulation of these peptides in the two paradigms suggests that the regulation is not due to the lower body weight but to the manner in which the paradigms achieved this lower body weight.
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Affiliation(s)
- Fa-Yun Che
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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40
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Czyzyk TA, Morgan DJ, Peng B, Zhang J, Karantzas A, Arai M, Pintar JE. Targeted mutagenesis of processing enzymes and regulators: Implications for development and physiology. J Neurosci Res 2003; 74:446-55. [PMID: 14598321 DOI: 10.1002/jnr.10792] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Traci A Czyzyk
- Department of Neuroscience and Cell Biology, UMDNJ-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA
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41
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Kikuchi K, Arawaka S, Koyama S, Kimura H, Ren CH, Wada M, Kawanami T, Kurita K, Daimon M, Kawakatsu S, Kadoya T, Goto K, Kato T. An N-terminal fragment of ProSAAS (a granin-like neuroendocrine peptide precursor) is associated with tau inclusions in Pick's disease. Biochem Biophys Res Commun 2003; 308:646-54. [PMID: 12914799 DOI: 10.1016/s0006-291x(03)01391-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The deposition of aggregated tau in cytoplasmic inclusions is one of the common neuropathological features in various dementing neurodegenerative disorders. At present, it remains unclear whether tau inclusions exert neurotoxicity or they are simply the consequence of neurodegeneration. In our approach for the analysis of the composition of tau inclusions, we detected the intense binding of anti-diacylglycerol kinase-zeta (DGK-zeta) antibodies to Pick bodies (PBs), which represent tau inclusions in Pick's disease. The polyclonal antibodies were found to cross-react with a 21-kDa protein, but not with tau or ubiquitin, on Western blots of normal human brain extracts. Analysis of the 21-kDa protein by two-dimensional-gel electrophoresis and mass-spectrometry revealed that the protein is an N-terminal fragment of proSAAS (a human granin-like neuroendocrine peptide precursor). Our results suggest that sequestration of the N-terminal fragment of proSAAS in intracellular PBs may cause a functional disturbance of neurons in Pick's disease.
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Affiliation(s)
- Kenji Kikuchi
- Third Department of Internal Medicine, Yamagata University School of Medicine, Japan
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Mzhavia N, Pan H, Che FY, Fricker LD, Devi LA. Characterization of endothelin-converting enzyme-2. Implication for a role in the nonclassical processing of regulatory peptides. J Biol Chem 2003; 278:14704-11. [PMID: 12560336 PMCID: PMC3862352 DOI: 10.1074/jbc.m211242200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Most neuroendocrine peptides are generated by proteolysis of the precursors at basic residue cleavage sites. Prohormone convertases belonging to the subtilisin family of serine proteases are primarily responsible for processing at these "classical sites." In addition to the classical cleavages, a subset of bioactive peptides is generated by processing at "nonclassical" sites. The proteases responsible for these cleavages have not been well explored. Members of several metalloprotease families have been proposed to be involved in nonclassical processing. Among them, endothelin-converting enzyme-2 (ECE-2) is a good candidate because it exhibits a neuroendocrine distribution and an acidic pH optimum. To examine the involvement of this protease in neuropeptide processing, we purified the recombinant enzyme and characterized its catalytic activity. Purified ECE-2 efficiently processes big endothelin-1 to endothelin-1 by cleavage between Trp(21) and Val(22) at acidic pH. To characterize the substrate specificity of ECE-2, we used mass spectrometry with a panel of 42 peptides as substrates to identify the products. Only 10 of these 42 peptides were processed by ECE-2. A comparison of residues around the cleavage site revealed that ECE-2 exhibits a unique cleavage site selectivity that is related to but distinct from that of ECE-1. ECE-2 tolerates a wide range of amino acids in the P1-position and prefers aliphatic/aromatic residues in the P1'-position. However, only a small fraction of the aliphatic/aromatic amino acid-containing sites were cleaved, indicating that there are additional constraints beyond the P1- and P1'-positions. The enzyme is able to generate a number of biologically active peptides from peptide intermediates, suggesting an important role for this enzyme in the biosynthesis of regulatory peptides. Also, ECE-2 processes proenkephalin-derived bovine adrenal medulla peptides, and this processing leads to peptide products known to have differential receptor selectivity. Finally, ECE-2 processes PEN-LEN, an endogenous inhibitor of prohormone convertase 1, into products that do not inhibit the enzyme. Taken together, these results are consistent with an important role for ECE-2 in the processing of regulatory peptides at nonclassical sites.
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Affiliation(s)
- Nino Mzhavia
- Department of Pharmacology and Biological Chemistry, Mount Sinai School of Medicine, New York, New York 10029
| | - Hui Pan
- Department of Pharmacology and Biological Chemistry, Mount Sinai School of Medicine, New York, New York 10029
| | - Fa-Yun Che
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Lloyd D. Fricker
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Lakshmi A. Devi
- Department of Pharmacology and Biological Chemistry, Mount Sinai School of Medicine, New York, New York 10029
- To whom correspondence should be addressed: Dept. of Pharmacology and Biological Chemistry, Box 1603, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029. Tel.: 212-241-8345; Fax: 212-996-7214;
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Che FY, Fricker LD. Quantitation of neuropeptides in Cpe(fat)/Cpe(fat) mice using differential isotopic tags and mass spectrometry. Anal Chem 2002; 74:3190-8. [PMID: 12141682 DOI: 10.1021/ac015681a] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Neuroendocrine peptides play important roles as intercellular messengers. We previously developed a technique to isolate and identify a large number of neuroendocrine peptides from Cpe(fat)/Cpe(fat) mice (Che, F.; et al. Proc. Natl. Acad. Sci. U.S.A. 2001, 98, 9971-6); these mice lack carboxypeptidase E activity and this defect causes an accumulation of neuropeptide intermediates that contain C-terminal Lys or Arg residues (Naggert, J. K.; et al. Nat. Genet. 1995, 10, 135-42). In the present study, we have developed a differential isotopic-labeling technique that can be used to quantitate changes in neuropeptide levels in Cpe(fat)/Cpe(fat) mouse tissues. Samples are treated with either the H6 or the D6 form of acetic anhydride, peptides that contain C-terminal basic amino acids are isolated by affinity chromatography on anhydrotrypsin agarose, and the isolated peptides are analyzed by mass spectrometry. Measurement of the regulation of pituitary peptides in response to dehydration showed a decrease in vasopressin. The general method described in this report should be widely applicable to a large number of neuroendocrine peptides, known and novel, in a variety of regulatory paradigms.
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Affiliation(s)
- Fa-yun Che
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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Abstract
Using a technique to identify substrates of the peptide processing enzyme carboxypeptidase E (CPE), several novel peptides were detected in the brain and pituitary of Cpe(fat)/Cpe(fat) mice and found to be derived from a single precursor, termed proSAAS. In order to gain further information regarding the potential physiological roles of these peptides, we have examined the distribution of two proSAAS-derived peptides, ARPVKEPRSLSAASAPLAETSTPLRL (SAAS) and LENSSPQAPARRLLPP (LEN), in rat neuroendocrine tissues using immunohistochemistry. Both peptides are detected throughout the brain, with the highest concentrations of SAAS peptide in the hypothalamus. In the hippocampus, both peptides are co-localized with prohormone convertase 1 in the dentate gyrus and CA1-3 region. In cerebellum, SAAS peptide is co-localized with prohormone convertase 1 in Purkinje and granular cells, whereas LEN is much more abundant in the Purkinje cells relative to the granular cells. Similarly, SAAS and prohormone convertase 1 are co-localized in the dorsal horn of the spinal cord, while LEN is mainly restricted to fibers of the white matter. In the pituitary, SAAS, LEN, and prohormone convertase 1 are detected in all three lobes. In the pancreas, SAAS, LEN, and prohormone convertase 1 are only detected in the islets, although the peptides are enriched in the peripheral cells (alpha and/or delta) while prohormone convertase 1 is only expressed in the inner cells (beta). Both SAAS and LEN are present in the adrenal medulla along with prohormone convertase 1. Taken together, these data are consistent with the proposed role for proSAAS as an endogenous inhibitor of prohormone convertase 1 in many, but not all cell types. However, the broader localization of the peptides allows for the possibility that they perform additional functions.
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Affiliation(s)
- Y Feng
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
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Mzhavia N, Qian Y, Feng Y, Che FY, Devi LA, Fricker LD. Processing of proSAAS in neuroendocrine cell lines. Biochem J 2002; 361:67-76. [PMID: 11742530 PMCID: PMC1222280 DOI: 10.1042/0264-6021:3610067] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
ProSAAS, a recently discovered granin-like protein, potently inhibits prohormone convertase (PC)1, and might also perform additional functions. In the present study, the processing of proSAAS was compared in two neuroendocrine cell lines overexpressing this protein: the AtT-20 mouse pituitary corticotrophic line and the PC12 rat adrenal phaeochromocytoma line. The processing of proSAAS was examined by pulse-chase analysis using [(3)H]leucine, by MS, and by chromatography and radioimmunoassay. Various smaller forms of proSAAS were detected, including peptides designated as little SAAS, PEN and big LEN. Because the PC-12 cells used in the present study do not express either PC1 or PC2, the finding that these cells efficiently cleave proSAAS indicates that these cleavages do not require either enzyme. Two of the peptides identified in AtT-20 media represent novel C-terminally truncated forms of PEN. In both cell lines, the secretion of the small proSAAS-derived peptides is stimulated by secretagogues. However, long-term treatment of wild-type AtT-20 cells with two different secretagogues (8-bromo-cAMP and a phorbol ester) does not affect levels of proSAAS mRNA; this treatment significantly increases PC1 mRNA by approx. 60-80%. The lack of co-regulation of proSAAS and PC1 mRNA implies that enzyme activity can be induced without an accompanying increase in the inhibitor. In addition, the finding that the peptides are secreted via the regulated pathway is consistent with the proposal that they may function as neuropeptides.
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Affiliation(s)
- Nino Mzhavia
- Department of Pharmacology, New York University School of Medicine, New York, NY 10016, U.S.A
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Basak A, Koch P, Dupelle M, Fricker LD, Devi LA, Chrétien M, Seidah NG. Inhibitory specificity and potency of proSAAS-derived peptides toward proprotein convertase 1. J Biol Chem 2001; 276:32720-8. [PMID: 11435430 DOI: 10.1074/jbc.m104064200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Prohormone convertase 1 (PC1), mediating the proteolytic processing of neural and endocrine precursors, is thought to be regulated by the neuroendocrine protein proSAAS. The PC1 inhibitory sequence is mostly confined within a 10-12-amino acid segment near the C terminus of the conserved human proSAAS and contains the critical KR(244) dibasic motif. Our results show that the decapeptide proSAAS-(235-244)( 235)VLGALLRVKR(244) is the most potent reversible competitive PC1-inhibitor (K(i) approximately 9 nm). The C-terminally extended proSAAS-(235-246) exhibits a 5-6-fold higher K(i) ( approximately 51 nm). The additional LE sequence at P1'-P2', resulted in a competitive substrate cleaved by PC1 at KR(244) downward arrowLE(246). Systematic alanine scanning and in some cases lysine scanning tested the contribution of each residue within proSAAS-(235-246) toward the PC1-inhibition's specificity and potency. The amino acids P1 Arg, P2 Lys, and P4 Arg are all critical for inhibition. Moreover, the aliphatic P3 Val and P5, P6, and P1' Leu significantly affect the degree of enzyme inactivation and PC1 specificity. Interestingly, a much longer N- and C-terminally extended endogenous rat proSAAS-(221-254) called little PenLen, was found to be a 3-fold less potent PC1 inhibitor with reduced selectivity but a much better substrate than proSAAS-(235-246). Molecular modeling studies and circular dichroism analysis indicate an extended and poly-l-proline II type structural conformation for proSAAS-(235-244), the most potent PC1 inhibitor, a feature not present in poor PC1 inhibitors.
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Affiliation(s)
- A Basak
- Laboratories of Molecular Medicine and Diseases of Ageing Center, Loeb Health Research Institute, The Ottawa Hospital, Ottawa, Ontario K1Y 4K9, Canada.
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