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Livnat I, Tai HC, Jansson ET, Bai L, Romanova EV, Chen TT, Yu K, Chen SA, Zhang Y, Wang ZY, Liu DD, Weiss KR, Jing J, Sweedler JV. A d-Amino Acid-Containing Neuropeptide Discovery Funnel. Anal Chem 2016; 88:11868-11876. [PMID: 27788334 PMCID: PMC5144109 DOI: 10.1021/acs.analchem.6b03658] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
![]()
A receptor binding
class of d-amino acid-containing peptides
(DAACPs) is formed in animals from an enzymatically mediated post-translational
modification of ribosomally translated all-l-amino acid peptides.
Although this modification can be required for biological actions,
detecting it is challenging because DAACPs have the same mass as their
all-l-amino acid counterparts. We developed a suite of mass
spectrometry (MS) protocols for the nontargeted discovery of DAACPs
and validated their effectiveness using neurons from Aplysia
californica. The approach involves the following three steps,
with each confirming and refining the hits found in the prior step.
The first step is screening for peptides resistant to digestion by
aminopeptidase M. The second verifies the presence of a chiral amino
acid via acid hydrolysis in deuterium chloride, labeling with Marfey’s
reagent, and liquid chromatography–mass spectrometry to determine
the chirality of each amino acid. The third involves synthesizing
the putative DAACPs and comparing them to the endogenous standards.
Advantages of the method, the d-amino acid-containing neuropeptide
discovery funnel, are that it is capable of detecting the d-form of any common chiral amino acid, and the first two steps do
not require peptide standards. Using these protocols, we report that
two peptides from the Aplysia achatin-like neuropeptide
precursor exist as GdYFD and SdYADSKDEESNAALSDFA.
Interestingly, GdYFD was bioactive in the Aplysia feeding and locomotor circuits but SdYADSKDEESNAALSDFA
was not. The discovery funnel provides an effective means to characterize
DAACPs in the nervous systems of animals in a nontargeted manner.
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Affiliation(s)
| | | | | | | | | | - Ting-Ting Chen
- 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, Jiangsu 210046, 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, Jiangsu 210046, China
| | - Song-An Chen
- 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, Jiangsu 210046, China
| | - Yan 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, Jiangsu 210046, China
| | - Zheng-Yang Wang
- 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, Jiangsu 210046, China
| | - Dan-Dan Liu
- 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, Jiangsu 210046, China
| | - Klaudiusz R Weiss
- Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai , New York, New York 10029, 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, Jiangsu 210046, China.,Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai , New York, New York 10029, United States
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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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Wardman JH, Gomes I, Bobeck EN, Stockert JA, Kapoor A, Bisignano P, Gupta A, Mezei M, Kumar S, Filizola M, Devi LA. Identification of a small-molecule ligand that activates the neuropeptide receptor GPR171 and increases food intake. Sci Signal 2016; 9:ra55. [PMID: 27245612 DOI: 10.1126/scisignal.aac8035] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Several neuropeptide systems in the hypothalamus, including neuropeptide Y and agouti-related protein (AgRP), control food intake. Peptides derived from proSAAS, a precursor implicated in the regulation of body weight, also control food intake. GPR171 is a heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptor (GPCR) for BigLEN (b-LEN), a peptide derived from proSAAS. To facilitate studies exploring the physiological role of GPR171, we sought to identify small-molecule ligands for this receptor by performing a virtual screen of a compound library for interaction with a homology model of GPR171. We identified MS0015203 as an agonist of GPR171 and demonstrated the selectivity of MS0015203 for GPR171 by testing the binding of this compound to 80 other membrane proteins, including family A GPCRs. Reducing the expression of GPR171 by shRNA (short hairpin RNA)-mediated knockdown blunted the cellular and tissue response to MS0015203. Peripheral injection of MS0015203 into mice increased food intake and body weight, and these responses were significantly attenuated in mice with decreased expression of GPR171 in the hypothalamus. Together, these results suggest that MS0015203 is a useful tool to probe the pharmacological and functional properties of GPR171 and that ligands targeting GPR171 may eventually lead to therapeutics for food-related disorders.
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Affiliation(s)
- Jonathan H Wardman
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - 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
| | - Jennifer A Stockert
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Abhijeet Kapoor
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Paola Bisignano
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Achla Gupta
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Mihaly Mezei
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Sanjai Kumar
- Department of Chemistry and Biochemistry, Queens College, Flushing, NY 11367, USA
| | - Marta Filizola
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Lakshmi A Devi
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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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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55
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Fricker LD. Limitations of Mass Spectrometry-Based Peptidomic Approaches. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2015; 26:1981-91. [PMID: 26305799 PMCID: PMC6597174 DOI: 10.1007/s13361-015-1231-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 07/02/2015] [Accepted: 07/03/2015] [Indexed: 05/23/2023]
Abstract
Mass spectrometry-based peptidomic approaches are powerful techniques to detect and identify the peptide content of biological samples. The present study investigated the limitations of peptidomic approaches using trimethylammonium butyrate isotopic tags to quantify relative peptide levels and Mascot searches to identify peptides. Data were combined from previous studies on human cell lines or mouse tissues. The combined databases contain 2155 unique peptides ranging in mass from 444 to 8765 Da, with the vast majority between 1 and 3 kDa. The amino acid composition of the identified peptides generally reflected the frequency in the Eukaryotic proteome with the exception of Cys, which was not present in any of the identified peptides in the free-SH form but was detected at low frequency as a disulfide with Cys residues, a disulfide with glutathione, or as S-cyanocysteine. To test if the low detection rate of peptides smaller than 500 Da, larger than 3 kDa, or containing Cys was a limitation of the peptidomics procedure, tryptic peptides of known proteins were processed for peptidomics using the same approach used for human cell lines and mouse tissues. The identified tryptic peptides ranged from 516 to 2418 Da, whereas the theoretical digest ranged from 217 to 7559 Da. Peptides with Cys were rarely detected and, if present, the Cys was usually modified S-cyanocysteine. Additionally, peptides with mono- and di-iodo Tyr and His were identified. Taken together, there are limitations of peptidomic techniques, and awareness of these limitations is important to properly use and interpret results. Graphical Abstract ᅟ.
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Affiliation(s)
- Lloyd D Fricker
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY, 10461, USA.
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Tein K, Kasvandik S, Kõks S, Vasar E, Terasmaa A. Prohormone convertase 2 activity is increased in the hippocampus of Wfs1 knockout mice. Front Mol Neurosci 2015; 8:45. [PMID: 26379490 PMCID: PMC4548212 DOI: 10.3389/fnmol.2015.00045] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 08/10/2015] [Indexed: 12/17/2022] Open
Abstract
Background: Mutations in WFS1 gene cause Wolfram syndrome, which is a rare autosomal recessive disorder, characterized by diabetes insipidus, diabetes mellitus, optic nerve atrophy, and deafness. The WFS1 gene product wolframin is located in the endoplasmic reticulum. Mice lacking this gene exhibit disturbances in the processing and secretion of peptides, such as vasopressin and insulin. In the brain, high levels of the wolframin protein have been observed in the hippocampus, amygdala, and limbic structures. The aim of this study was to investigate the effect of Wfs1 knockout (KO) on peptide processing in mouse hippocampus. A peptidomic approach was used to characterize individual peptides in the hippocampus of wild-type and Wfs1 KO mice. Results: We identified 126 peptides in hippocampal extracts and the levels of 10 peptides differed between Wfs1 KO and wild-type mice at P < 0.05. The peptide with the largest alteration was little-LEN, which level was 25 times higher in the hippocampus of Wfs1 KO mice compared to wild-type mice. Processing (cleavage) of little-LEN from the Pcsk1n gene product proSAAS involves prohormone convertase 2 (PC2). Thus, PC2 activity was measured in extracts prepared from the hippocampus of Wfs1 KO mice. The activity of PC2 in Wfs1 mutant mice was significantly higher (149.9 ± 2.3%, p < 0.0001, n = 8) than in wild-type mice (100.0 ± 7.0%, n = 8). However, Western blot analysis showed that protein levels of 7B2, proPC2 and PC2 were same in both groups, and so were gene expression levels. Conclusion: Processing of proSAAS is altered in the hippocampus of Wfs1-KO mice, which is caused by increased activity of PC2. Increased activity of PC2 in Wfs1 KO mice is not caused by alteration in the levels of PC2 protein. Our results suggest a functional link between Wfs1 and PC2. Thus, the detailed molecular mechanism of the role of Wfs1 in the regulation of PC2 activity needs further investigation.
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Affiliation(s)
- Karin Tein
- Department of Physiology, Institute of Biomedicine and Translational Medicine, University of Tartu Tartu, Estonia
| | - Sergo Kasvandik
- Proteomics core facility, Institute of Technology, University of Tartu Tartu, Estonia
| | - Sulev Kõks
- Department of Pathophysiology, Institute of Biomedicine and Translational Medicine, University of Tartu Tartu, Estonia ; Department of Reproductive Biology, Estonian University of Life Sciences Tartu, Estonia
| | - Eero Vasar
- Department of Physiology, Institute of Biomedicine and Translational Medicine, University of Tartu Tartu, Estonia
| | - Anton Terasmaa
- Department of Physiology, Institute of Biomedicine and Translational Medicine, University of Tartu Tartu, Estonia
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Urban DJ, Roth BL. DREADDs (designer receptors exclusively activated by designer drugs): chemogenetic tools with therapeutic utility. Annu Rev Pharmacol Toxicol 2014; 55:399-417. [PMID: 25292433 DOI: 10.1146/annurev-pharmtox-010814-124803] [Citation(s) in RCA: 436] [Impact Index Per Article: 43.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In the past decade, emerging synthetic biology technologies such as chemogenetics have dramatically transformed how pharmacologists and systems biologists deconstruct the involvement of G protein-coupled receptors (GPCRs) in a myriad of physiological and translational settings. Here we highlight a specific chemogenetic application that extends the utility of the concept of RASSLs (receptors activated solely by synthetic ligands): We have dubbed it DREADDs (designer receptors exclusively activated by designer drugs). As we show in this review, DREADDs are now used ubiquitously to modulate GPCR activity noninvasively in vivo. Results from these studies have directly implicated GPCR signaling in a large number of therapeutically relevant contexts. We also highlight recent applications of DREADD technology that have illuminated GPCR signaling processes that control pathways relevant to the treatment of eating disorders, obesity, and obesity-associated metabolic abnormalities. Additionally, we provide an overview of the potential utility of chemogenetic technologies for transformative therapeutics.
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58
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Gupta A, Fujita W, Gomes I, Bobeck E, Devi LA. Endothelin-converting enzyme 2 differentially regulates opioid receptor activity. Br J Pharmacol 2014; 172:704-19. [PMID: 24990314 DOI: 10.1111/bph.12833] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 06/17/2014] [Accepted: 06/24/2014] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND AND PURPOSE Opioid receptor function is modulated by post-activation events such as receptor endocytosis, recycling and/or degradation. While it is generally understood that the peptide ligand gets co-endocytosed with the receptor, relatively few studies have investigated the role of the endocytosed peptide and peptide processing enzymes in regulating receptor function. In this study, we focused on endothelin-converting enzyme 2 (ECE2), a member of the neprilysin family of metallopeptidases that exhibits an acidic pH optimum, localizes to an intracellular compartment and selectively processes neuropeptides including opioid peptides in vitro, and examined its role in modulating μ receptor recycling and resensitization. EXPERIMENTAL APPROACH The effect of ECE2 inhibition on hydrolysis of the endocytosed peptide was examined using thin-layer chromatography and on μ opioid receptor trafficking using either elisa or microscopy. The effect of ECE2 inhibition on receptor signalling was measured using a cAMP assay and, in vivo, on antinociception induced by intrathecally administered opioids by the tail-flick assay. KEY RESULTS The highly selective ECE2 inhibitor, S136492, significantly impaired μ receptor recycling and signalling by only those ligands that are ECE2 substrates and this was seen both in heterologous cells and in cells endogenously co-expressing μ receptors with ECE2. We also found that ECE2 inhibition attenuated antinociception mediated only by opioid peptides that are ECE2 substrates. CONCLUSIONS AND IMPLICATIONS These results suggest that ECE2, by selectively processing endogenous opioid peptides in the endocytic compartment, plays a role in modulating opioid receptor activity. LINKED ARTICLES This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2.
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Affiliation(s)
- A Gupta
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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59
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Khatib N, Gaidhane S, Gaidhane AM, Khatib M, Simkhada P, Gode D, Zahiruddin QS. Ghrelin: ghrelin as a regulatory Peptide in growth hormone secretion. J Clin Diagn Res 2014; 8:MC13-7. [PMID: 25302229 DOI: 10.7860/jcdr/2014/9863.4767] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 06/12/2014] [Indexed: 12/19/2022]
Abstract
BACKGROUND Ghrelin is a type of growth hormone (GH) secretagogue that stimulates the release of GH. It is a first hormone linking gastrointestinal-pituitary axis. OBJECTIVE This review highlights the interaction of ghrelin with GHRH and somatostatin to regulate the secretion of GH and intends to explore the possible physiological role of the ghrelin-pituitary-GH axis linkage system. OBSERVATION Ghrelin is highly conserved among species and is classified into octanoylated (C8:0), decanoylated (C10:0), decenoylated (C10:1) and nonacylated,ghrelin. Acylated ghrelin is the major active form of human ghrelin. The primary production site of ghrelin is the stomach, and it interacts with stomach ghrelin as well as hypothalamic GHRH and somatostatin in the regulation of pituitary GH secretion. Ghrelin stimulate GH release through the GHS receptor to increase intracellular Ca2+ ([Ca2+] levels via IP3 signal transduction pathway. Ghrelin is a specific endogenous ligand for the GHS receptor and provides a definitive proof of the occurance of a GHS-GHS receptor signalling system in the regulation of GH secretion. CONCLUSION Studies suggests that ghrelin is a powerful pharmacological agent that exerts a potent, time-dependent stimulation of pulsatile secretion of GH.
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Affiliation(s)
- Nazli Khatib
- Associate Professor, Department of Physiology, Datta Meghe Institute of Medical Sciences , Sawangi (Meghe), Wardha, India
| | - Shilpa Gaidhane
- Assistant Professor, Department of Community Medicine, Datta Meghe Institute of Medical Sciences , Sawangi (Meghe), Wardha, India
| | - Abhay M Gaidhane
- Professor, Department of Community Medicine, J N Medical College, Datta Meghe Institute of Medical Sciences , Sawangi (Meghe), Wardha, India
| | - Mahanaaz Khatib
- Pharmacovigilance Co-ordinator, i3global , Pune Maharashtra, India
| | - Padam Simkhada
- Senior Lecturer, International Health School of Health and Related Research (ScHARR),University of Sheffield , UK
| | - Dilip Gode
- Vice Chancellor, Datta Meghe Institute of Medical Sciences , Sawangi (Meghe), Wardha, India
| | - Quazi Syed Zahiruddin
- Associate Dean, Professor, Department of Community Medicine, Datta Meghe Institute of Medical Sciences , Sawangi (Meghe), Wardha, India
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60
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Schrader M, Schulz-Knappe P, Fricker LD. Historical perspective of peptidomics. EUPA OPEN PROTEOMICS 2014. [DOI: 10.1016/j.euprot.2014.02.014] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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61
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Gupta A, Gomes I, Wardman J, Devi LA. Opioid receptor function is regulated by post-endocytic peptide processing. J Biol Chem 2014; 289:19613-26. [PMID: 24847082 DOI: 10.1074/jbc.m113.537704] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Most neuroendocrine peptides are generated in the secretory compartment by proteolysis of the precursors at classical cleavage sites consisting of basic residues by well studied endopeptidases belonging to the subtilisin superfamily. In contrast, a subset of bioactive peptides is generated by processing at non-classical cleavage sites that do not contain basic residues. Neither the peptidases responsible for non-classical cleavages nor the compartment involved in such processing has been well established. Members of the endothelin-converting enzyme (ECE) family are considered good candidate enzymes because they exhibit functional properties that are consistent with such a role. In this study we have explored a role for ECE2 in endocytic processing of δ opioid peptides and its effect on modulating δ opioid receptor function by using selective inhibitors of ECE2 that we had identified previously by homology modeling and virtual screening of a library of small molecules. We found that agonist treatment led to intracellular co-localization of ECE2 with δ opioid receptors. Furthermore, selective inhibitors of ECE2 and reagents that increase the pH of the acidic compartment impaired receptor recycling by protecting the endocytosed peptide from degradation. This, in turn, led to a substantial decrease in surface receptor signaling. Finally, we showed that treatment of primary neurons with the ECE2 inhibitor during recycling led to increased intracellular co-localization of the receptors and ECE2, which in turn led to decreased receptor recycling and signaling by the surface receptors. Together, these results support a role for differential modulation of opioid receptor signaling by post-endocytic processing of peptide agonists by ECE2.
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Affiliation(s)
- Achla Gupta
- From the Department of Pharmacology and Systems Therapeutics and
| | - Ivone Gomes
- From the Department of Pharmacology and Systems Therapeutics and
| | - Jonathan Wardman
- From the Department of Pharmacology and Systems Therapeutics and
| | - Lakshmi A Devi
- From the Department of Pharmacology and Systems Therapeutics and the Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029
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62
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Sapio MR, Fricker LD. Carboxypeptidases in disease: insights from peptidomic studies. Proteomics Clin Appl 2014; 8:327-37. [PMID: 24470285 DOI: 10.1002/prca.201300090] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 10/10/2013] [Accepted: 10/30/2013] [Indexed: 12/19/2022]
Abstract
Carboxypeptidases (CPs) perform many diverse physiological functions by removing C-terminal amino acids from proteins and peptides. Some CPs function in the degradation of proteins in the digestive tract while other enzymes play biosynthetic roles in the formation of neuropeptides and peptide hormones. Another set of CPs modify tubulin by removing amino acids from the C-terminus and from polyglutamyl side chains, thereby altering the properties of microtubules. This review focuses on three CPs: carboxypeptidase E, carboxypeptidase A6, and cytosolic carboxypeptidase 1. Naturally occurring mutations in all three of these enzymes are associated with disease phenotypes, ranging from obesity to epilepsy to neurodegeneration. Peptidomics is a useful tool to investigate the relationship between these mutations and alterations in peptide levels. This technique has also been used to define the function and characteristics of CPs. Results from peptidomics studies have helped to elucidate the function of CPs and clarify the biological underpinnings of pathologies by identifying peptides altered in disease states. This review describes the use of peptidomic techniques to gain insights into the normal function of CPs and the molecular defects caused by mutations in the enzymes.
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Affiliation(s)
- Matthew R Sapio
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA
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