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Yoon MC, Ames J, Mosier C, Jiang Z, Podvin S, O’Donoghue AJ, Hook V. Distinct Dibasic Cleavage Specificities of Neuropeptide-Producing Cathepsin L and Cathepsin V Cysteine Proteases Compared to PC1/3 and PC2 Serine Proteases. ACS Chem Neurosci 2022; 13:245-256. [PMID: 34986304 DOI: 10.1021/acschemneuro.1c00653] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Neuropeptides, functioning as peptide neurotransmitters and hormones, are generated from proneuropeptide precursors by proteolytic processing at dibasic residue sites (i.e., KR, RK, KK, RR). The cysteine proteases cathepsin L and cathepsin V, combined with the serine proteases proprotein convertases 1 and 2 (PC1/3 and PC2), participate in proneuropeptide processing to generate active neuropeptides. To compare the dibasic cleavage properties of these proteases, this study conducted global, unbiased substrate profiling of these processing proteases using a diverse peptide library in multiplex substrate profiling by mass spectrometry (MSP-MS) assays. MSP-MS utilizes a library of 228 14-mer peptides designed to contain all possible protease cleavage sites, including the dibasic residue sites of KR, RK, KK, and RR. The comprehensive MSP-MS analyses demonstrated that cathepsin L and cathepsin V cleave at the N-terminal side and between the dibasic residues (e.g., ↓K↓R, ↓R↓K, and K↓K), with a preference for hydrophobic residues at the P2 position of the cleavage site. In contrast, the serine proteases PC1/3 and PC2 displayed cleavage at the C-terminal side of dibasic residues of a few peptide substrates. Further analyses with a series of dipeptide-AMC and tripeptide-AMC substrates containing variant dibasic sites with hydrophobic P2 residues indicated the preferences of cathepsin L and cathepsin V to cleave between dibasic residue sites with preferences for flanking hydrophobic residues at the P2 position consisting of Leu, Trp, Phe, and Tyr. Such hydrophobic amino acids reside in numerous proneuropeptides such as pro-NPY and proenkephalin that are known to be processed by cathepsin L. Notably, cathepsin L displayed the highest specific activity that was 10-, 64-, and 1268-fold greater than cathepsin V, PC1/3, and PC2, respectively. Peptide-AMC substrates with dibasic residues confirmed that PC1/3 and P2 cleaved almost exclusively at the C-terminal side of dibasic residues. These data demonstrate distinct dibasic cleavage site properties and a broad range of proteolytic activities of cathepsin L and cathepsin V, compared to PC1/3 and PC2, which participate in producing neuropeptides for cell-cell communication.
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Affiliation(s)
- Michael C. Yoon
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Dr. MC0657, La Jolla, California 92093, United States
| | - Janneca Ames
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Dr. MC0657, La Jolla, California 92093, United States
| | - Charles Mosier
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Dr. MC0657, La Jolla, California 92093, United States
| | - Zhenze Jiang
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Dr. MC0657, La Jolla, California 92093, United States
| | - Sonia Podvin
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Dr. MC0657, La Jolla, California 92093, United States
| | - Anthony J. O’Donoghue
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Dr. MC0657, La Jolla, California 92093, United States
| | - Vivian Hook
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Dr. MC0657, La Jolla, California 92093, United States
- Department of Neurosciences and Department of Pharmacology, University of California, San Diego, La Jolla, California 92093, United States
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Ramzy A, Kieffer TJ. Altered islet prohormone processing: A cause or consequence of diabetes? Physiol Rev 2021; 102:155-208. [PMID: 34280055 DOI: 10.1152/physrev.00008.2021] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Peptide hormones are first produced as larger precursor prohormones that require endoproteolytic cleavage to liberate the mature hormones. A structurally conserved but functionally distinct family of nine prohormone convertase enzymes (PCs) are responsible for cleavage of protein precursors of which PC1/3 and PC2 are known to be exclusive to neuroendocrine cells and responsible for prohormone cleavage. Differential expression of PCs within tissues define prohormone processing; whereas glucagon is the major product liberated from proglucagon via PC2 in pancreatic α-cells, proglucagon is preferentially processed by PC1/3 in intestinal L cells to produce glucagon-like peptides 1 and 2 (GLP-1, GLP-2). Beyond our understanding of processing of islet prohormones in healthy islets, there is convincing evidence that proinsulin, proIAPP, and proglucagon processing is altered during prediabetes and diabetes. There is predictive value of elevated circulating proinsulin or proinsulin : C-peptide ratio for progression to type 2 diabetes and elevated proinsulin or proinsulin : C-peptide is predictive for development of type 1 diabetes in at risk groups. After onset of diabetes, patients have elevated circulating proinsulin and proIAPP and proinsulin may be an autoantigen in type 1 diabetes. Further, preclinical studies reveal that α-cells have altered proglucagon processing during diabetes leading to increased GLP-1 production. We conclude that despite strong associative data, current evidence is inconclusive on the potential causal role of impaired prohormone processing in diabetes, and suggest that future work should focus on resolving the question of whether altered prohormone processing is a causal driver or merely a consequence of diabetes pathology.
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Affiliation(s)
- Adam Ramzy
- Laboratory of Molecular and Cellular Medicine, Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - Timothy J Kieffer
- Laboratory of Molecular and Cellular Medicine, Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada.,Department of Surgery, University of British Columbia, Vancouver, BC, Canada.,School of Biomedical Engineering, University of British Columbia, Vancouver, BC, Canada
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Jiang Z, Lietz CB, Podvin S, Yoon MC, Toneff T, Hook V, O’Donoghue AJ. Differential Neuropeptidomes of Dense Core Secretory Vesicles (DCSV) Produced at Intravesicular and Extracellular pH Conditions by Proteolytic Processing. ACS Chem Neurosci 2021; 12:2385-2398. [PMID: 34153188 PMCID: PMC8267839 DOI: 10.1021/acschemneuro.1c00133] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
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Neuropeptides mediate
cell–cell signaling in the nervous
and endocrine systems. The neuropeptidome is the spectrum of peptides
generated from precursors by proteolysis within dense core secretory
vesicles (DCSV). DCSV neuropeptides and contents are released to the
extracellular environment where further processing for neuropeptide
formation may occur. To assess the DCSV proteolytic capacity for production
of neuropeptidomes at intravesicular pH 5.5 and extracellular pH 7.2,
neuropeptidomics, proteomics, and protease assays were conducted using
chromaffin granules (CG) purified from adrenal medulla. CG are an
established model of DCSV. The CG neuropeptidome consisted of 1239
unique peptides derived from 15 proneuropeptides that were colocalized
with 64 proteases. Distinct CG neuropeptidomes were generated at the
internal DCSV pH of 5.5 compared to the extracellular pH of 7.2. Class-specific
protease inhibitors differentially regulated neuropeptidome production
involving aspartic, cysteine, serine, and metallo proteases. The substrate
cleavage properties of CG proteases were assessed by multiplex substrate
profiling by mass spectrometry (MSP-MS) that uses a synthetic peptide
library containing diverse cleavage sites for endopeptidases and exopeptidases.
Parallel inhibitor-sensitive cleavages for neuropeptidome production
and peptide library proteolysis led to elucidation of six CG proteases
involved in neuropeptidome production, represented by cathepsins A,
B, C, D, and L and carboxypeptidase E (CPE). The MSP-MS profiles of
these six enzymes represented the majority of CG proteolytic cleavages
utilized for neuropeptidome production. These findings provide new
insight into the DCSV proteolytic system for production of distinct
neuropeptidomes at the internal CG pH of 5.5 and at the extracellular
pH of 7.2.
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Affiliation(s)
- Zhenze Jiang
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - Christopher B. Lietz
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
| | - Sonia Podvin
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
| | - Michael C. Yoon
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
| | - Thomas Toneff
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
| | - Vivian Hook
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
- Department of Neuroscience and Department of Pharmacology, University of California, San Diego, La Jolla, California 92093, United States
| | - Anthony J. O’Donoghue
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
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Saidi M, Beaudry F. Targeted high-resolution quadrupole-Orbitrap mass spectrometry analyses reveal a significant reduction of tachykinin and opioid neuropeptides level in PC1 and PC2 mutant mouse spinal cords. Neuropeptides 2017; 65:37-44. [PMID: 28476408 DOI: 10.1016/j.npep.2017.04.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 03/09/2017] [Accepted: 04/13/2017] [Indexed: 12/30/2022]
Abstract
Tachykinin and opioid neuropeptides play a fundamental role in pain transmission, modulation and inhibition. The proteolysis control of endogenous tachykinin and opioid neuropeptides has a significant impact on pain perception. The role of proprotein convertases (PCs) in the proteolysis of proneuropeptides was previously established but very few studies have shown the direct impact of PCs on the regulation of specific tachykinin and opioid peptides in the central nervous system. There is an increasing interest in the therapeutic targeting of PCs for the treatment of pain but it is imperative to assess the impact of PCs on the pronociceptive and the endogenous opioid systems. The objective of this study was to determine the relative concentration of targeted neuropeptides in the spinal cord of WT, PC1-/+ and PC2-/+ animals to establish the impact of a restricted PCs activity on the regulation of specific neuropeptides. The analysis of tachykinin and opioid neuropeptides were performed on a HPLC-MS/MS (High-Resolution Quadrupole-Orbitrap Mass Spectrometer). The results revealed a significant decrease of Dyn A (p<0.01), Leu-Enk (p<0.001), Met-Enk (p<0.001), Tach58-71 (p<0.05), SP (p<0.01) and NKA (p<0.001) concentrations in both, PC1-/+ and PC2-/+ animals. Therefore, the modulation of PCs activity has an important impact on specific pronociceptive peptides (SP and NKA), but the results also shown that endogenous opioid system is hindered and consequently it will affect significantly the pain modulatory pathways. These observations may have insightful impact on future analgesic drug developments and therapeutic strategies.
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Affiliation(s)
- Mouna Saidi
- Groupe de Recherche en Pharmacologie Animal du Québec (GREPAQ), Département de biomédecine vétérinaire, Faculté de médecine vétérinaire, Université de Montréal, St-Hyacinthe, Québec, Canada
| | - Francis Beaudry
- Groupe de Recherche en Pharmacologie Animal du Québec (GREPAQ), Département de biomédecine vétérinaire, Faculté de médecine vétérinaire, Université de Montréal, St-Hyacinthe, Québec, Canada.
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Saidi M, Kamali S, Beaudry F. Characterization of Substance P processing in mouse spinal cord S9 fractions using high-resolution Quadrupole-Orbitrap mass spectrometry. Neuropeptides 2016; 59:47-55. [PMID: 27344070 DOI: 10.1016/j.npep.2016.06.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 06/13/2016] [Accepted: 06/16/2016] [Indexed: 11/17/2022]
Abstract
Tachykinins are a family of pronociceptive neuropeptides with a specific role in pain and inflammation. Several mechanisms regulate endogenous tachykinins and Substance P (SP) levels, including the differential expression of protachykinin mRNA and the controlled secretion of tachykinins from neurons. Proteolysis is suspected to regulate extracellular SP concentrations but few studies were conducted on the metabolism of proneuropeptides and neuropeptides. Here, we provide evidence that proteolysis controls SP levels in the spinal cord leading to the formation of active C-terminal fragments. Using high-resolution mass spectrometry, specific tachykinins fragments were characterized and quantified. The metabolic stability of β-Tachykinin58-71 and SP were very short resulting in half-life of 5.7 and 3.5min respectively. Several C-terminal fragments were identified, including SP3-11, SP5-11 and SP8-11, which conserve affinity for the Neurokinin 1 receptor. Interestingly, the metabolic stability of C-terminal fragments was significantly superior. Two specific Prolyl endopeptidase inhibitors were used and showed a significant reduction in the rate of formation of SP3-11 and SP5-11 providing strong evidence that Prolyl endopeptidase is involved into N-terminal processing of SP in the spinal cord.
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Affiliation(s)
- Mouna Saidi
- Groupe de Recherche en Pharmacologie Animal du Québec (GREPAQ), Département de Biomédecine Vétérinaire, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada
| | - Soufiane Kamali
- Groupe de Recherche en Pharmacologie Animal du Québec (GREPAQ), Département de Biomédecine Vétérinaire, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada
| | - Francis Beaudry
- Groupe de Recherche en Pharmacologie Animal du Québec (GREPAQ), Département de Biomédecine Vétérinaire, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada.
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6
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Stijnen P, Ramos-Molina B, O'Rahilly S, Creemers JWM. PCSK1 Mutations and Human Endocrinopathies: From Obesity to Gastrointestinal Disorders. Endocr Rev 2016; 37:347-71. [PMID: 27187081 DOI: 10.1210/er.2015-1117] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Prohormone convertase 1/3, encoded by the PCSK1 gene, is a serine endoprotease that is involved in the processing of a variety of proneuropeptides and prohormones. Humans who are homozygous or compound heterozygous for loss-of-function mutations in PCSK1 exhibit a variable and pleiotropic syndrome consisting of some or all of the following: obesity, malabsorptive diarrhea, hypogonadotropic hypogonadism, altered thyroid and adrenal function, and impaired regulation of plasma glucose levels in association with elevated circulating proinsulin-to-insulin ratio. Recently, more common variants in the PCSK1 gene have been found to be associated with alterations in body mass index, increased circulating proinsulin levels, and defects in glucose homeostasis. This review provides an overview of the endocrinopathies and other disorders observed in prohormone convertase 1/3-deficient patients, discusses the possible biochemical basis for these manifestations of the disease, and proposes a model whereby certain missense mutations in PCSK1 may result in proteins with a dominant negative action.
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Affiliation(s)
- Pieter Stijnen
- Laboratory for Biochemical Neuroendocrinology (P.S., B.R.-M., J.W.M.C.), Department of Human Genetics, KU Leuven, Leuven 3000, Belgium; and Medical Research Council (MRC) Metabolic Diseases Unit (S.O.), Wellcome Trust-MRC Institute of Metabolic Science, National Institute for Health Research, Cambridge Biomedical Research Centre, Addenbrooke's Hospital, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - Bruno Ramos-Molina
- Laboratory for Biochemical Neuroendocrinology (P.S., B.R.-M., J.W.M.C.), Department of Human Genetics, KU Leuven, Leuven 3000, Belgium; and Medical Research Council (MRC) Metabolic Diseases Unit (S.O.), Wellcome Trust-MRC Institute of Metabolic Science, National Institute for Health Research, Cambridge Biomedical Research Centre, Addenbrooke's Hospital, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - Stephen O'Rahilly
- Laboratory for Biochemical Neuroendocrinology (P.S., B.R.-M., J.W.M.C.), Department of Human Genetics, KU Leuven, Leuven 3000, Belgium; and Medical Research Council (MRC) Metabolic Diseases Unit (S.O.), Wellcome Trust-MRC Institute of Metabolic Science, National Institute for Health Research, Cambridge Biomedical Research Centre, Addenbrooke's Hospital, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - John W M Creemers
- Laboratory for Biochemical Neuroendocrinology (P.S., B.R.-M., J.W.M.C.), Department of Human Genetics, KU Leuven, Leuven 3000, Belgium; and Medical Research Council (MRC) Metabolic Diseases Unit (S.O.), Wellcome Trust-MRC Institute of Metabolic Science, National Institute for Health Research, Cambridge Biomedical Research Centre, Addenbrooke's Hospital, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
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7
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Orduna AR, Beaudry F. Characterization of endoproteolytic processing of dynorphins by proprotein convertases using mouse spinal cord S9 fractions and mass spectrometry. Neuropeptides 2016; 57:85-94. [PMID: 26578270 DOI: 10.1016/j.npep.2015.10.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 10/09/2015] [Accepted: 10/11/2015] [Indexed: 12/21/2022]
Abstract
Dynorphins are important neuropeptides with a central role in nociception and pain alleviation. Many mechanisms regulate endogenous dynorphin concentrations, including proteolysis. Proprotein convertases (PCs) are widely expressed in the central nervous system and specifically cleave at C-terminal of either a pair of basic amino acids, or a single basic residue. The proteolysis control of endogenous big dynorphin (BDyn) and dynorphin A (Dyn A) levels has a profound impact on pain perception and the role of PCs remain unclear. The objective of this study was to decipher the role of PC1 and PC2 in the proteolysis control of BDyn and Dyn A levels using cellular fractions of spinal cords from wild-type (WT), PC1(-/+) and PC2(-/+) animals and mass spectrometry. Our results clearly demonstrate that both PC1 and PC2 are involved in the proteolysis regulation of BDyn and Dyn A with a more important role for PC1. C-terminal processing of BDyn generates specific peptide fragments dynorphin 1-19, dynorphin 1-13, dynorphin 1-11 and dynorphin 1-7, and C-terminal processing of Dyn A generates dynorphin 1-13, dynorphin 1-11 and dynorphin 1-7, all these peptide fragments are associated with PC1 or PC2 processing. Moreover, the proteolysis of BDyn leads to the formation of Dyn A and Leu-Enk, two important opioid peptides. The rate of formation of both is significantly reduced in cellular fractions of spinal cord mutant mice. As a consequence, even the partial inhibition of PC1 or PC2 may impair the endogenous opioid system.
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Affiliation(s)
- Alberto Ruiz Orduna
- Groupe de Recherche en Pharmacologie Animal du Québec (GREPAQ), Faculté de Médecine Vétérinaire, Département de Biomédecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada
| | - Francis Beaudry
- Groupe de Recherche en Pharmacologie Animal du Québec (GREPAQ), Faculté de Médecine Vétérinaire, Département de Biomédecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada.
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Turpeinen H, Ortutay Z, Pesu M. Genetics of the first seven proprotein convertase enzymes in health and disease. Curr Genomics 2014; 14:453-67. [PMID: 24396277 PMCID: PMC3867721 DOI: 10.2174/1389202911314050010] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 09/13/2013] [Accepted: 09/14/2013] [Indexed: 12/16/2022] Open
Abstract
Members of the substilisin/kexin like proprotein convertase (PCSK) protease family cleave and convert immature pro-proteins into their biologically active forms. By cleaving for example prohormones, cytokines and cell membrane proteins, PCSKs participate in maintaining the homeostasis in a healthy human body. Conversely, erratic enzymatic function is thought to contribute to the pathogenesis of a wide variety of diseases, including obesity and hypercholestrolemia. The first characterized seven PCSK enzymes (PCSK1-2, FURIN, PCSK4-7) process their substrates at a motif made up of paired basic amino acid residues. This feature results in a variable degree of biochemical redundancy in vitro, and consequently, shared substrate molecules between the different PCSK enzymes. This redundancy has confounded our understanding of the specific biological functions of PCSKs. The physiological roles of these enzymes have been best illustrated by the phenotypes of genetically engineered mice and patients that carry mutations in the PCSK genes. Recent developments in genome-wide methodology have generated a large amount of novel information on the genetics of the first seven proprotein convertases. In this review we summarize the reported genetic alterations and their associated phenotypes.
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Affiliation(s)
- Hannu Turpeinen
- Immunoregulation, Institute of Biomedical Technology, University of Tampere, and BioMediTech, Tampere, Finland
| | - Zsuzsanna Ortutay
- Immunoregulation, Institute of Biomedical Technology, University of Tampere, and BioMediTech, Tampere, Finland
| | - Marko Pesu
- Immunoregulation, Institute of Biomedical Technology, University of Tampere, and BioMediTech, Tampere, Finland; ; Fimlab laboratories, Pirkanmaa Hospital District, Finland
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Lu WD, Funkelstein L, Toneff T, Reinheckel T, Peters C, Hook V. Cathepsin H functions as an aminopeptidase in secretory vesicles for production of enkephalin and galanin peptide neurotransmitters. J Neurochem 2012; 122:512-22. [PMID: 22582844 PMCID: PMC3417130 DOI: 10.1111/j.1471-4159.2012.07788.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Peptide neurotransmitters function as key intercellular signaling molecules in the nervous system. These peptides are generated in secretory vesicles from proneuropeptides by proteolytic processing at dibasic residues, followed by removal of N- and/or C-terminal basic residues to form active peptides. Enkephalin biosynthesis from proenkephalin utilizes the cysteine protease cathepsin L and the subtilisin-like prohormone convertase 2 (PC2). Cathepsin L generates peptide intermediates with N-terminal basic residue extensions, which must be removed by an aminopeptidase. In this study, we identified cathepsin H as an aminopeptidase in secretory vesicles that produces (Met)enkephalin (ME) by sequential removal of basic residues from KR-ME and KK-ME, supported by in vivo knockout of the cathepsin H gene. Localization of cathepsin H in secretory vesicles was demonstrated by immunoelectron microscopy and immunofluorescence deconvolution microscopy. Purified human cathepsin H sequentially removes N-terminal basic residues to generate ME, with peptide products characterized by nano-LC-MS/MS tandem mass spectrometry. Cathepsin H shows highest activities for cleaving N-terminal basic residues (Arg and Lys) among amino acid fluorogenic substrates. Notably, knockout of the cathepsin H gene results in reduction of ME in mouse brain. Cathepsin H deficient mice also show a substantial decrease in galanin peptide neurotransmitter levels in brain. These results illustrate a role for cathepsin H as an aminopeptidase for enkephalin and galanin peptide neurotransmitter production.
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Affiliation(s)
- Weiya Douglas Lu
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, CA, USA
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Funkelstein L, Lu WD, Koch B, Mosier C, Toneff T, Taupenot L, O'Connor DT, Reinheckel T, Peters C, Hook V. Human cathepsin V protease participates in production of enkephalin and NPY neuropeptide neurotransmitters. J Biol Chem 2012; 287:15232-41. [PMID: 22393040 PMCID: PMC3346103 DOI: 10.1074/jbc.m111.310607] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Revised: 02/23/2012] [Indexed: 12/11/2022] Open
Abstract
Proteases are required for processing precursors into active neuropeptides that function as neurotransmitters for cell-cell communication. This study demonstrates the novel function of human cathepsin V protease for producing the neuropeptides enkephalin and neuropeptide Y (NPY). Cathepsin V is a human-specific cysteine protease gene. Findings here show that expression of cathepsin V in neuroendocrine PC12 cells and human neuronal SK-N-MC cells results in production of (Met)enkephalin from proenkephalin. Gene silencing of cathepsin V by siRNA in human SK-N-MC cells results in reduction of (Met)enkephalin by more than 80%, illustrating the prominent role of cathepsin V for neuropeptide production. In vitro processing of proenkephalin by cathepsin V occurs at dibasic residue sites to generate enkephalin-containing peptides and an ∼24-kDa intermediate present in human brain. Cathepsin V is present in human brain cortex and hippocampus where enkephalin and NPY are produced and is present in purified human neuropeptide secretory vesicles. Colocalization of cathepsin V with enkephalin and NPY in secretory vesicles of human neuroblastoma cells was illustrated by confocal microscopy. Furthermore, expression of cathepsin V with proNPY results in NPY production. These findings indicate the unique function of human cathepsin V for producing enkephalin and NPY neuropeptides required for neurotransmission in health and neurological diseases.
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Affiliation(s)
- Lydiane Funkelstein
- From the Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, California 92093
| | - W. Douglas Lu
- From the Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, California 92093
| | - Britta Koch
- the Institut für Molekulare Medizin und Zellforschung, Albert-Ludwigs Universitat, Freiburg, Germany D-79104 Freiburg
| | - Charles Mosier
- From the Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, California 92093
| | - Thomas Toneff
- From the Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, California 92093
| | - Laurent Taupenot
- the Department of Medicine, University of California, San Diego, California 92093
| | - Daniel T. O'Connor
- the Department of Medicine, University of California, San Diego, California 92093
| | - Thomas Reinheckel
- the Institut für Molekulare Medizin und Zellforschung, Albert-Ludwigs Universitat, Freiburg, Germany D-79104 Freiburg
- BIOSS Centre for Biological Signaling Studies, D-79104 Freiburg, Germany, and
| | - Christoph Peters
- the Institut für Molekulare Medizin und Zellforschung, Albert-Ludwigs Universitat, Freiburg, Germany D-79104 Freiburg
- BIOSS Centre for Biological Signaling Studies, D-79104 Freiburg, Germany, and
| | - Vivian Hook
- From the Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, California 92093
- the Department of Medicine, University of California, San Diego, California 92093
- the Departments of of Neurosciences, Pharmacology, and Medicine, University of California, San Diego, La Jolla, California 92093
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Hook V, Funkelstein L, Wegrzyn J, Bark S, Kindy M, Hook G. Cysteine Cathepsins in the secretory vesicle produce active peptides: Cathepsin L generates peptide neurotransmitters and cathepsin B produces beta-amyloid of Alzheimer's disease. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2011; 1824:89-104. [PMID: 21925292 DOI: 10.1016/j.bbapap.2011.08.015] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2011] [Revised: 08/26/2011] [Accepted: 08/29/2011] [Indexed: 12/01/2022]
Abstract
Recent new findings indicate significant biological roles of cysteine cathepsin proteases in secretory vesicles for production of biologically active peptides. Notably, cathepsin L in secretory vesicles functions as a key protease for proteolytic processing of proneuropeptides (and prohormones) into active neuropeptides that are released to mediate cell-cell communication in the nervous system for neurotransmission. Moreover, cathepsin B in secretory vesicles has been recently identified as a β-secretase for production of neurotoxic β- amyloid (Aβ) peptides that accumulate in Alzheimer's disease (AD), participating as a notable factor in the severe memory loss in AD. These secretory vesicle functions of cathepsins L and B for production of biologically active peptides contrast with the well-known role of cathepsin proteases in lysosomes for the degradation of proteins to result in their inactivation. The unique secretory vesicle proteome indicates proteins of distinct functional categories that provide the intravesicular environment for support of cysteine cathepsin functions. Features of the secretory vesicle protein systems insure optimized intravesicular conditions that support the proteolytic activity of cathepsins. These new findings of recently discovered biological roles of cathepsins L and B indicate their significance in human health and disease. This article is part of a Special Issue entitled: Proteolysis 50 years after the discovery of lysosome.
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Affiliation(s)
- Vivian Hook
- Skaggs School of Pharmacy and Pharmaceutical Sciences, Dept. of Neurosciences, Univ. of Calif., San Diego, USA.
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Gagnon J, Mayne J, Chen A, Raymond A, Woulfe J, Mbikay M, Chrétien M. PCSK2-null mice exhibit delayed intestinal motility, reduced refeeding response and altered plasma levels of several regulatory peptides. Life Sci 2011; 88:212-7. [DOI: 10.1016/j.lfs.2010.11.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Revised: 10/10/2010] [Accepted: 11/08/2010] [Indexed: 11/24/2022]
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Funkelstein L, Beinfeld M, Minokadeh A, Zadina J, Hook V. Unique biological function of cathepsin L in secretory vesicles for biosynthesis of neuropeptides. Neuropeptides 2010; 44:457-66. [PMID: 21047684 PMCID: PMC3058267 DOI: 10.1016/j.npep.2010.08.003] [Citation(s) in RCA: 39] [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] [Received: 05/18/2010] [Revised: 08/05/2010] [Accepted: 08/30/2010] [Indexed: 11/18/2022]
Abstract
Neuropeptides are essential for cell-cell communication in the nervous and neuroendocrine systems. Production of active neuropeptides requires proteolytic processing of proneuropeptide precursors in secretory vesicles that produce, store, and release neuropeptides that regulate physiological functions. This review describes recent findings indicating the prominent role of cathepsin L in secretory vesicles for production of neuropeptides from their protein precursors. The role of cathepsin L in neuropeptide production was discovered using the strategy of activity-based probes for proenkephalin-cleaving activity for identification of the enzyme protein by mass spectrometry. The novel role of cathepsin L in secretory vesicles for neuropeptide production has been demonstrated in vivo by cathepsin L gene knockout studies, cathepsin L gene expression in neuroendocrine cells, and notably, cathepsin L localization in neuropeptide-containing secretory vesicles. Cathepsin L is involved in producing opioid neuropeptides consisting of enkephalin, β-endorphin, and dynorphin, as well as in generating the POMC-derived peptide hormones ACTH and α-MSH. In addition, NPY, CCK, and catestatin neuropeptides utilize cathepsin L for their biosynthesis. The neuropeptide-synthesizing functions of cathepsin L represent its unique activity in secretory vesicles, which contrasts with its role in lysosomes. Interesting evaluations of protease gene knockout studies in mice that lack cathepsin L compared to those lacking PC1/3 and PC2 (PC, prohormone convertase) indicate the key role of cathepsin L in neuropeptide production. Therefore, dual cathepsin L and prohormone convertase protease pathways participate in neuropeptide production. Significantly, the recent new findings indicate cathepsin L as a novel 'proprotein convertase' for production of neuropeptides that mediate cell-cell communication in health and disease.
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Affiliation(s)
- Lydiane Funkelstein
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093, USA
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Collins JJ, Hou X, Romanova EV, Lambrus BG, Miller CM, Saberi A, Sweedler JV, Newmark PA. Genome-wide analyses reveal a role for peptide hormones in planarian germline development. PLoS Biol 2010; 8:e1000509. [PMID: 20967238 PMCID: PMC2953531 DOI: 10.1371/journal.pbio.1000509] [Citation(s) in RCA: 195] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Accepted: 08/25/2010] [Indexed: 12/02/2022] Open
Abstract
Genomic/peptidomic analyses of the planarian Schmidtea mediterranea identifies >200 neuropeptides and uncovers a conserved neuropeptide required for proper maturation and maintenance of the reproductive system. Bioactive peptides (i.e., neuropeptides or peptide hormones) represent the largest class of cell-cell signaling molecules in metazoans and are potent regulators of neural and physiological function. In vertebrates, peptide hormones play an integral role in endocrine signaling between the brain and the gonads that controls reproductive development, yet few of these molecules have been shown to influence reproductive development in invertebrates. Here, we define a role for peptide hormones in controlling reproductive physiology of the model flatworm, the planarian Schmidtea mediterranea. Based on our observation that defective neuropeptide processing results in defects in reproductive system development, we employed peptidomic and functional genomic approaches to characterize the planarian peptide hormone complement, identifying 51 prohormone genes and validating 142 peptides biochemically. Comprehensive in situ hybridization analyses of prohormone gene expression revealed the unanticipated complexity of the flatworm nervous system and identified a prohormone specifically expressed in the nervous system of sexually reproducing planarians. We show that this member of the neuropeptide Y superfamily is required for the maintenance of mature reproductive organs and differentiated germ cells in the testes. Additionally, comparative analyses of our biochemically validated prohormones with the genomes of the parasitic flatworms Schistosoma mansoni and Schistosoma japonicum identified new schistosome prohormones and validated half of all predicted peptide-encoding genes in these parasites. These studies describe the peptide hormone complement of a flatworm on a genome-wide scale and reveal a previously uncharacterized role for peptide hormones in flatworm reproduction. Furthermore, they suggest new opportunities for using planarians as free-living models for understanding the reproductive biology of flatworm parasites. Flatworms cause diseases affecting hundreds of millions of people, so understanding what influences their reproductive activity is of fundamental importance. Neurally derived signals have been suggested to coordinate sexual reproduction in free-living flatworms, yet the neuroendocrine signaling repertoire has not been characterized comprehensively for any flatworm. Neuropeptides are a large diverse group of cell-cell signaling molecules and play many roles in vertebrate reproductive development; however, little is known about their function in reproductive development among invertebrates. Here we use biochemical and bioinformatic techniques to identify bioactive peptides in the genome of the planarian flatworm Schmidtea mediterranea and identify 51 genes encoding >200 peptides. Analysis of these genes in both sexual and asexual strains of S. mediterranea identified a neuropeptide Y superfamily member as important for the normal development and maintenance of the planarian reproductive system. We suggest that understanding peptide hormone function in planarian reproduction could have practical implications in the treatment of parasitic flatworms.
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Affiliation(s)
- James J. Collins
- Howard Hughes Medical Institute and Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Xiaowen Hou
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Elena V. Romanova
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Bramwell G. Lambrus
- Howard Hughes Medical Institute and Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Claire M. Miller
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Amir Saberi
- Howard Hughes Medical Institute and Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Jonathan V. Sweedler
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Phillip A. Newmark
- Howard Hughes Medical Institute and Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- * E-mail:
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Genetic deficiency for proprotein convertase subtilisin/kexin type 2 in mice is associated with decreased adiposity and protection from dietary fat-induced body weight gain. Int J Obes (Lond) 2010; 34:1599-607. [PMID: 20498660 DOI: 10.1038/ijo.2010.90] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND Proprotein convertase subtilisin/xexin type 2 (PCSK2) is an endoproteinase responsible for proteolytic activation of a number of precursors to active neuropeptides and peptide hormones, known to influence glucose homeostasis, food intake and ultimately body mass. In this study, we examined the consequences of PCSK2 deficiency on these phenotypic traits. STUDY DESIGN Weight gain with age under diets of different fat contents was monitored. White adipose tissue (WAT) and muscle masses were evaluated. Plasma levels of triglycerides, leptin, ghrelin, insulin and proglucagon-derived peptides were measured as well as leptin and acetyl coenzyme-α carboxylase (ACCα) mRNA levels in adipose tissue. RESULTS Compared with their Pcsk2 (+/+) littermates, Pcsk2 (-/-) mice weighed significantly less as weanlings and as adults. As adults, they carried noticeably less fat mass, with similar lean muscle mass: their plasma leptin level and adipose tissue leptin mRNA level were accordingly lower. PCSK2 deficiency did not affect food intake or the level of the orexigenic hormone ghrelin. However, PCSK2 deficiency resulted in decreased plasma triglycerides and reduced ACCα mRNA levels in WAT. Interestingly, unlike their Pcsk2 (+/+) littermates, Pcsk2 (-/-) were resistant to enhanced body weight gain when fed a high-fat diet. Consistent with a role of PCSK2 in body mass gain, diet-induced or genetically obese mice were found to contain significantly higher levels of PCSK2 mRNA in their brain and stomach than their lean counterparts. CONCLUSION Collectively, these results suggest that PCSK2 contributes to increase in body mass through the various regulatory peptides generated through its action. It represents a potential target in the prevention and treatment of obesity.
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Abstract
Vasoactive intestinal polypeptide (VIP) is derived from a 170 amino acid precursor which in addition is processed to preproVIP 22-79, PHI, preproVIP 111-122 and preproVIP 156-170. All preproVIP-derived peptides have been shown in normal tissue and VIP-producing cell lines and elevated quantities occur in plasma and tumour tissues from patients with VIP-producing tumours. In some tissues the dibasic cleavage site after PHI is uncleaved resulting in a C-terminally extended form, PHV. PHI and VIP are present in a 1:1 molar ratio in large dense core vesicles and released in roughly equimolar amounts. Carboxyamidation of VIP and PHI is not critical and glycine-extended forms of both peptides have been demonstrated. Pituitary adenylate cyclase activating polypeptide (PACAP) is derived from a 170 amino acid long precursor, which gives rise to PACAP 38, PACAP 27 and PACAP related peptide (PRP). All peptides are present in tissue, the dominating form being PACAP 38. Prohormone convertase (PC) 1 and 2 seem to be involved in the processing of PACAP, except in the testes and ovary, where the PACAP precursor is substrate for PC4.
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Zhang X, Pan H, Peng B, Steiner DF, Pintar JE, Fricker LD. Neuropeptidomic analysis establishes a major role for prohormone convertase-2 in neuropeptide biosynthesis. J Neurochem 2009; 112:1168-79. [PMID: 19968759 DOI: 10.1111/j.1471-4159.2009.06530.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Prohormone convertase 2 (PC2) functions in the generation of neuropeptides from their precursors. A quantitative peptidomics approach was used to evaluate the role of PC2 in the processing of peptides in a variety of brain regions. Altogether, 115 neuropeptides or other peptides derived from secretory pathway proteins were identified. These peptides arise from 28 distinct secretory pathway proteins, including proenkephalin, proopiomelanocortin, prodynorphin, protachykinin A and B, procholecystokinin, and many others. Forty one of the peptides found in wild-type (WT) mice were not detectable in any of the brain regions of PC2 knockout mice, and another 24 peptides were present at levels ranging from 20% to 79% of WT levels. Most of the other peptides were not substantially affected by the mutation, with levels ranging from 80% to 120% of WT levels, and only three peptides were found to increase in one or more brain regions of PC2 knockout mice. Taken together, these results are consistent with a broad role for PC2 in neuropeptide processing, but with functional redundancy for many of the cleavages. Comparison of the cleavage sites affected by the absence of PC2 confirms previous suggestions that sequences with a Trp, Tyr, and/or Pro in the P1' or P2' position are preferentially cleaved by PC2 and not by other enzymes present in the secretory pathway.
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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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Minokadeh A, Funkelstein L, Toneff T, Hwang SR, Beinfeld M, Reinheckel T, Peters C, Zadina J, Hook V. Cathepsin L participates in dynorphin production in brain cortex, illustrated by protease gene knockout and expression. Mol Cell Neurosci 2009; 43:98-107. [PMID: 19837164 DOI: 10.1016/j.mcn.2009.10.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Revised: 09/15/2009] [Accepted: 10/05/2009] [Indexed: 02/08/2023] Open
Abstract
Dynorphin opioid neuropeptides mediate neurotransmission for analgesia and behavioral functions. Dynorphin A, dynorphin B, and alpha-neoendorphin are generated from prodynorphin by proteolytic processing. This study demonstrates the significant role of the cysteine protease cathepsin L for producing dynorphins. Cathepsin L knockout mouse brains showed extensive decreases in dynorphin A, dynorphin B, and alpha-neoendorphin that were reduced by 75%, 83%, and 90%, respectively, compared to controls. Moreover, cathepsin L in brain cortical neurons was colocalized with dynorphins in secretory vesicles, the primary site of neuropeptide production. Cellular coexpression of cathepsin L with prodynorphin in PC12 cells resulted in increased production of dynorphins A and B. Comparative studies of PC1/3 and PC2 convertases showed that PC1/3 knockout mouse brains had a modest decrease in dynorphin A, and PC2 knockout mice showed a minor decrease in alpha-neoendorphin. Overall, these results demonstrate a prominent role for cathepsin L, jointly with PC1/3 and PC2, for production of dynorphins in brain.
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Affiliation(s)
- Ardalan Minokadeh
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, USA
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20
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Pro-protein convertase-2/carboxypeptidase-E mediated neuropeptide processing of RGC-5 cell after in vitro ischemia. Neurosci Bull 2009; 25:7-14. [PMID: 19190683 DOI: 10.1007/s12264-009-1027-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
OBJECTIVE To observe the change of the neuropeptide pro-protein processing system in the ischemic retina ganglion cell-5 (RGC-5) cells, pro-protein convertase-2 (PC2), carboxypeptidase-E (CPE) and preproneuropeptide Y (preproNPY) protein levels in the ischemic RGC-5 cells and conditioned medium were analyzed. METHODS The RGC-5 cell was differentiated in 0.1 mumol/L staurosporine for 24 h and then stressed by different doses of oxygen and glucose deprivation (OGD). The acute or chronic OGD-induced cell death rates were obtained by using PI or TUNEL staining. The protein expression levels were determined by using the Western blot method and PC2 activity analysis. RESULTS The ischemia caused substantial cell death in an OGD dose-dependent manner. In the cells, proPC2 and preproNPY protein levels gradually increased whereas proCPE gradually decreased. After OGD, PC2 activity was decreased. In the conditioned medium, proPC2 and PC2 proteins gradually decreased whereas proCPE, CPE, and preproNPY proteins gradually increased. CONCLUSION These results demonstrated that OGD inhibited the neuropeptide pro-protein processing system by reducing PC2 activity and the maturation of proPC2. The aggregation of the pro-proteins and the increase of the active CPE excision adversely exacerbated the cell injury. The pro-protein processing system might play a critical role in the ischemic stress of RGC-5 cells.
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Tang SS, Zhang JH, Liu HX, Li HZ. PC2/CPE-mediated pro-protein processing in tumor cells and its differentiated cells or tissues. Mol Cell Endocrinol 2009; 303:43-9. [PMID: 19428990 PMCID: PMC7116944 DOI: 10.1016/j.mce.2009.01.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2008] [Revised: 01/22/2009] [Accepted: 01/27/2009] [Indexed: 11/26/2022]
Abstract
Pro-protein convertase-2 (PC2) and carboxypeptidase-E (CPE) proteins are two major members of the pro-protein convertases that involve in the maturation of protein precursor. By using PC2 activity, immunocytochemistry (ICC) and Western blot method, PC2, CPE and preproNPY protein expression levels were compared among mature retina tissue, RGC-5 cells and its differentiated cells, or brain cortex tissue, NS20Y tumor cells and its differentiated cells, or mature breast tissue, breast tumor cell RM1 and breast adenocarcinoma tissue. The experimental results indicated that the differentiated cells or tissues had higher or highest PC2 activity. In the comparative experiments, more PC2 protein expression in the mature tissues and more CPE and preproNPY protein expression in the tumor cells or tumor tissue were observed, but no expression of preproNPY protein was observed in the mature tissues. Compared with NS20Y or RGC-5 undifferentiated cells, its differentiated cells showed less proPC2, more proCPE and more preproNPY protein expressions. The results demonstrated that the mature tissues showed stronger PC2/CPE-mediated pro-protein processing ability than the tumor cells or tissue. The results also showed that the artificial differentiation of RGC-5 or NS20Y cells was different from maturation of its corresponding normal tissue.
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Affiliation(s)
- Song-Shan Tang
- Department of Biochemistry, School of Basic Courses, Guangdong Pharmaceutical University, Guangzhou, China.
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22
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Bark SJ, Lu WD, Hook V. Linear and accurate quantitation of proenkephalin-derived peptides by isotopic labeling with internal standards and mass spectrometry. Anal Biochem 2009; 389:18-26. [PMID: 19289094 DOI: 10.1016/j.ab.2009.03.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2008] [Revised: 02/13/2009] [Accepted: 03/08/2009] [Indexed: 11/27/2022]
Abstract
Proenkephalin (PE) represents the precursor protein of the active peptide neurotransmitter enkephalin. Quantitative analysis of peptides and proteins is an objective of mass spectrometry-based studies of biological systems and will be important for studying the proteolytic conversion of proproteins to active enkephalin and neuropeptides. The goal of this study was to define and optimize quantitation of different amounts of tryptic peptides derived from PE using light (H4, 4 hydrogens) and heavy (D4, 4 deuteriums) succinic anhydride for isotopic labeling of peptides analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Comparisons were made between PE-derived peptides with and without internal standards. Importantly, incorporation of internal standards of known amounts of heavy isotope-labeled tryptic peptides of PE provided linear calibration plots with accurate quantitation. In contrast, comparison of light and heavy isotope-labeled peptides without internal standards produced variable and inaccurate nonlinear isotopic ratio comparisons of PE-derived peptides. These results demonstrate that use of internal standards composed of a defined amount(s) of standard peptides (PE-derived tryptic peptides) is necessary for high-quality linear quantitation of peptides by isotopic labeling and MS/MS.
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Affiliation(s)
- Steven J Bark
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, 9500 Gilman Drive, MC-744, San Diego, La Jolla, CA 92093, USA.
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Funkelstein L, Toneff T, Hwang SR, Reinheckel T, Peters C, Hook V. Cathepsin L participates in the production of neuropeptide Y in secretory vesicles, demonstrated by protease gene knockout and expression. J Neurochem 2008; 106:384-91. [PMID: 18410501 DOI: 10.1111/j.1471-4159.2008.05408.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Neuropeptide Y (NPY) functions as a peptide neurotransmitter and as a neuroendocrine hormone. The active NPY peptide is generated in secretory vesicles by proteolytic processing of proNPY. Novel findings from this study show that cathepsin L participates as a key proteolytic enzyme for NPY production in secretory vesicles. Notably, NPY levels in cathepsin L knockout (KO) mice were substantially reduced in brain and adrenal medulla by 80% and 90%, respectively. Participation of cathepsin L in producing NPY predicts their colocalization in secretory vesicles, a primary site of NPY production. Indeed, cathepsin L was colocalized with NPY in brain cortical neurons and in chromaffin cells of adrenal medulla, demonstrated by immunofluorescence confocal microscopy. Immunoelectron microscopy confirmed the localization of cathepsin L with NPY in regulated secretory vesicles of chromaffin cells. Functional studies showed that coexpression of proNPY with cathepsin L in neuroendocrine PC12 cells resulted in increased production of NPY. Furthermore, in vitro processing indicated cathepsin L processing of proNPY at paired basic residues. These findings demonstrate a role for cathepsin L in the production of NPY from its proNPY precursor. These studies illustrate the novel biological role of cathepsin L in the production of NPY, a peptide neurotransmitter, and neuroendocrine hormone.
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Affiliation(s)
- Lydiane Funkelstein
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093-0744, USA
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Hook V, Funkelstein L, Lu D, Bark S, Wegrzyn J, Hwang SR. Proteases for processing proneuropeptides into peptide neurotransmitters and hormones. Annu Rev Pharmacol Toxicol 2008; 48:393-423. [PMID: 18184105 PMCID: PMC2731677 DOI: 10.1146/annurev.pharmtox.48.113006.094812] [Citation(s) in RCA: 185] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Peptide neurotransmitters and peptide hormones, collectively known as neuropeptides, are required for cell-cell communication in neurotransmission and for regulation of endocrine functions. Neuropeptides are synthesized from protein precursors (termed proneuropeptides or prohormones) that require proteolytic processing primarily within secretory vesicles that store and secrete the mature neuropeptides to control target cellular and organ systems. This review describes interdisciplinary strategies that have elucidated two primary protease pathways for prohormone processing consisting of the cysteine protease pathway mediated by secretory vesicle cathepsin L and the well-known subtilisin-like proprotein convertase pathway that together support neuropeptide biosynthesis. Importantly, this review discusses important areas of current and future biomedical neuropeptide research with respect to biological regulation, inhibitors, structural features of proneuropeptide and protease interactions, and peptidomics combined with proteomics for systems biological approaches. Future studies that gain in-depth understanding of protease mechanisms for generating active neuropeptides will be instrumental for translational research to develop pharmacological strategies for regulation of neuropeptide functions. Pharmacological applications for neuropeptide research may provide valuable therapeutics in health and disease.
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Affiliation(s)
- Vivian Hook
- Skaggs School of Pharmacy and Pharmaceutical Sciences, and Department of Neuroscience, Pharmacology, and Medicine, School of Medicine, University of California-San Diego, La Jolla, CA 92093-0744, USA.
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25
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Husson SJ, Janssen T, Baggerman G, Bogert B, Kahn-Kirby AH, Ashrafi K, Schoofs L. Impaired processing of FLP and NLP peptides in carboxypeptidase E (EGL-21)-deficient Caenorhabditis elegans as analyzed by mass spectrometry. J Neurochem 2007; 102:246-60. [PMID: 17564681 DOI: 10.1111/j.1471-4159.2007.04474.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Biologically active peptides are synthesized from inactive pre-proproteins or peptide precursors by the sequential actions of processing enzymes. Proprotein convertases cleave the precursor at pairs of basic amino acids, which are then removed from the carboxyl terminus of the generated fragments by a specific carboxypeptidase. Caenorhabditis elegans strains lacking proprotein convertase EGL-3 display a severely impaired neuropeptide profile (Husson et al. 2006, J. Neurochem.98, 1999-2012). In the present study, we examined the role of the C. elegans carboxypeptidase E orthologue EGL-21 in the processing of peptide precursors. More than 100 carboxy-terminally extended neuropeptides were detected in egl-21 mutant strains. These findings suggest that EGL-21 is a major carboxypeptidase involved in the processing of FMRFamide-like peptide (FLP) precursors and neuropeptide-like protein (NLP) precursors. The impaired peptide profile of egl-3 and egl-21 mutants is reflected in some similar phenotypes. They both share a severe widening of the intestinal lumen, locomotion defects, and retention of embryos. In addition, egl-3 animals have decreased intestinal fat content. Taken together, these results suggest that EGL-3 and EGL-21 are key enzymes for the proper processing of neuropeptides that control egg-laying, locomotion, fat storage and the nutritional status.
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Affiliation(s)
- Steven J Husson
- Functional Genomics and Proteomics Unit, Department of Biology, Katholieke Universiteit Leuven, Leuven, Belgium.
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Bataille D. Pro-protein convertases in intermediary metabolism: islet hormones, brain/gut hormones and integrated physiology. J Mol Med (Berl) 2007; 85:673-84. [PMID: 17356847 DOI: 10.1007/s00109-007-0167-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2006] [Revised: 01/18/2007] [Accepted: 01/25/2007] [Indexed: 11/24/2022]
Abstract
Many peptide hormones implicated in the regulation of intermediary metabolism arise from larger precursors called prohormones. These precursors are cut into pieces by proprotein convertases, more precisely those called prohormone convertases (PCs) that cleave at the C terminus of basic doublets. The remaining basic amino acids are eliminated by a specialized carboxypeptidase, leading to the active hormone. This processing may provide, from a single precursor, several peptides with different biological activities depending on the site(s) of cleavage on the precursor. When the processing is tissue-specific, this mechanism allows to produce, from a single protein, different sets of hormones depending on the tissue considered, leading to novel regulatory processes. The archetype of such a pluripotent prohormone in the field of intermediary metabolism is pro-glucagon that, when cut by PC1 in intestinal L cells, produces four different peptides with different specificities [glicentin, oxyntomodulin (OXM), glucagon-like peptide-1, and glucagon-like peptide-2], whereas, when cut by PC2 in the alpha cells of the endocrine pancreas, glucagon is produced and, through the supplementary action of NRD convertase, a fragment of glucagon (miniglucagon) with original properties.
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Affiliation(s)
- Dominique Bataille
- Inserm U376, CHU Arnaud-de-Villeneuve, 34295, Montpellier Cedex 05, France.
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Hwang SR, Garza C, Mosier C, Toneff T, Wunderlich E, Goldsmith P, Hook V. Cathepsin L expression is directed to secretory vesicles for enkephalin neuropeptide biosynthesis and secretion. J Biol Chem 2007; 282:9556-9563. [PMID: 17244622 DOI: 10.1074/jbc.m605510200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Proteases within secretory vesicles are required for conversion of neuropeptide precursors into active peptide neurotransmitters and hormones. This study demonstrates the novel cellular role of the cysteine protease cathepsin L for producing the (Met)enkephalin peptide neurotransmitter from proenkephalin (PE) in the regulated secretory pathway of neuroendocrine PC12 cells. These findings were achieved by coexpression of PE and cathepsin L cDNAs in PC12 cells with analyses of PE-derived peptide products. Expression of cathepsin L resulted in highly increased cellular levels of (Met)enkephalin, resulting from the conversion of PE to enkephalin-containing intermediates of 23, 18-19, 8-9, and 4.5 kDa that were similar to those present in vivo. Furthermore, expression of cathepsin L with PE resulted in increased amounts of nicotine-induced secretion of (Met)enkephalin. These results indicate increased levels of (Met)enkephalin within secretory vesicles of the regulated secretory pathway. Importantly, cathespin L expression was directed to secretory vesicles, demonstrated by colocalization of cathepsin L-DsRed fusion protein with enkephalin and chromogranin A neuropeptides that are present in secretory vesicles. In vivo studies also showed that cathepsin L in vivo was colocalized with enkephalin. The newly defined secretory vesicle function of cathepsin L for biosynthesis of active enkephalin opioid peptide contrasts with its function in lysosomes for protein degradation. These findings demonstrate cathepsin L as a distinct cysteine protease pathway for producing the enkephalin member of neuropeptides.
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Affiliation(s)
- Shin-Rong Hwang
- Skaggs School of Pharmacy and Pharmaceutical Sciences and Departments of Pharmacology, Neuroscience, and Medicine, School of Medicine, University of California, San Diego, La Jolla, California 92093
| | - Christina Garza
- Skaggs School of Pharmacy and Pharmaceutical Sciences and Departments of Pharmacology, Neuroscience, and Medicine, School of Medicine, University of California, San Diego, La Jolla, California 92093
| | - Charles Mosier
- Skaggs School of Pharmacy and Pharmaceutical Sciences and Departments of Pharmacology, Neuroscience, and Medicine, School of Medicine, University of California, San Diego, La Jolla, California 92093
| | - Thomas Toneff
- Skaggs School of Pharmacy and Pharmaceutical Sciences and Departments of Pharmacology, Neuroscience, and Medicine, School of Medicine, University of California, San Diego, La Jolla, California 92093
| | | | - Paul Goldsmith
- College of Pharmacy, Touro University, Vallejo, California 94592
| | - Vivian Hook
- Skaggs School of Pharmacy and Pharmaceutical Sciences and Departments of Pharmacology, Neuroscience, and Medicine, School of Medicine, University of California, San Diego, La Jolla, California 92093.
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Hook VYH. Unique neuronal functions of cathepsin L and cathepsin B in secretory vesicles: biosynthesis of peptides in neurotransmission and neurodegenerative disease. Biol Chem 2006; 387:1429-39. [PMID: 17081116 DOI: 10.1515/bc.2006.179] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Proteases are required for the production of peptide neurotransmitters and toxic peptides in neurodegenerative diseases. Unique roles of the cysteine proteases cathepsin L and cathepsin B in secretory vesicles for the production of biologically active peptides have been demonstrated in recent studies. Secretory vesicle cathepsin L participates in the proteolytic conversion of proenkephalin into the active enkephalin, an opioid peptide neurotransmitter that mediates pain relief. Moreover, recent findings provide evidence that cathepsin B in regulated secretory vesicles participates in the production of toxic beta-amyloid peptides that are known to accumulate extracellularly in Alzheimer's disease brains. The neurobiological functions of cathepsins L and B demonstrate that these secretory vesicle cysteine proteases produce biologically active peptides. These results demonstrate newly identified roles for cathepsins L and B in neurosecretory vesicles in the production of biologically active peptides.
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Affiliation(s)
- Vivian Y H Hook
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, School of Medicine, University of California at San Diego, La Jolla, 92093-0744, USA.
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Husson SJ, Clynen E, Baggerman G, Janssen T, Schoofs L. Defective processing of neuropeptide precursors in Caenorhabditis elegans lacking proprotein convertase 2 (KPC-2/EGL-3): mutant analysis by mass spectrometry. J Neurochem 2006; 98:1999-2012. [PMID: 16945111 DOI: 10.1111/j.1471-4159.2006.04014.x] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Biologically active peptides are synthesized as larger inactive proprotein peptide precursors which are processed by the concerted action of a cascade of enzymes. Among the proprotein convertases, PC2 is widely expressed in neuro-endocrine tissues and has been proposed to be the major convertase involved in the biosynthesis of neuropeptides. In this study, we have examined the role of the Caenorhabditis elegans orthologue PC2/EGL-3 in the processing of proprotein peptide precursors. We recently isolated and identified 60 endogenous peptides in the nematode C. elegans by two-dimensional nanoscale liquid chromatography - quadrupole time-of-flight tandem mass spectrometry. In the present study, we compare the peptide profile of different C. elegans strains, including PC2/EGL-3 mutants. For this purpose, we used an offline approach in which HPLC fractions are analysed by a matrix-assisted laser desorption ionisation - time of flight mass spectrometer. This differential peptidomic approach unambiguously provides evidence for the role of PC2/EGL-3 in the processing of FMRFamide-like peptide (FLP) precursors and neuropeptide-like protein (NLP) precursors in nematodes.
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Affiliation(s)
- Steven J Husson
- Laboratory of Developmental Physiology, Genomics and Proteomics, Katholieke Universiteit Leuven, Leuven, Belgium.
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Croissandeau G, Wahnon F, Yashpal K, Seidah NG, Coderre TJ, Chrétien M, Mbikay M. Increased stress-induced analgesia in mice lacking the proneuropeptide convertase PC2. Neurosci Lett 2006; 406:71-5. [PMID: 16905251 DOI: 10.1016/j.neulet.2006.07.031] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2006] [Revised: 07/04/2006] [Accepted: 07/06/2006] [Indexed: 11/20/2022]
Abstract
Many neuropeptides involved in pain perception are generated by endoproteolytic cleavages of their precursor proteins by the proprotein convertases PC1 and PC2. To investigate the role of PC2 in nociception and analgesia, we tested wild-type and PC2-null mice for their responses to mechanical and thermal nociceptive stimuli, before and after a short swim in cold or warm water. Basal responses and responses after a cold swim were similar between the two groups. However, after a short forced swim in warm water, PC2-null mice were significantly less responsive to the stimuli than wild-type mice, an indication of increased opioid-mediated stress-induced analgesia. The enhanced analgesia in PC2-null mice may be caused by an accumulation of opioid precursor processing intermediates with potent analgesic effects, or by loss of anti-opioid peptides.
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Affiliation(s)
- Gilles Croissandeau
- Ottawa Health Research Institute, The Ottawa Hospital, 725 Parkdale Avenue, University of Ottawa, Ottawa, Ontario K1Y 4E9, Canada
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Pan H, Che FY, Peng B, Steiner DF, Pintar JE, Fricker LD. The role of prohormone convertase-2 in hypothalamic neuropeptide processing: a quantitative neuropeptidomic study. J Neurochem 2006; 98:1763-77. [PMID: 16903874 DOI: 10.1111/j.1471-4159.2006.04067.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Prohormone convertase (PC) 1/3 and 2 are involved in the generation of neuropeptides from their precursors. A quantitative peptidomic approach was used to explore the role PC2 plays in the processing of hypothalamic peptides. In this approach, extracts from mice lacking PC2 activity and from wild-type littermates were labeled with isotopic tags, combined, fractionated on a reverse phase HPLC column, and analyzed by electrospray ionization mass spectrometry. Altogether, 53 neuropeptides or other peptides derived from secretory pathway proteins were identified and sequenced using tandem mass spectrometry. These peptides arise from 21 distinct proteins: proenkephalin, proopiomelanocortin, prodynorphin, protachykinin A and B, procholecystokinin, promelanin-concentrating hormone, proneurotensin, proneuropeptide Y, provasopressin, pronociceptin/orphanin, prothyrotropin-releasing hormone, cocaine- and amphetamine-regulated transcript, chromogranin A and B, secretogranin II, prohormone convertase 1 and 2, propeptidyl-amidating monooxygenase, and proteins designated proSAAS and VGF. Approximately one third of the peptides found in wild-type mice were not detectable in PC2 knock-out mice, and another third were present at levels ranging from 25 to 75% of wild-type levels. Comparison of the cleavage sites suggests that sequences with a Trp, Tyr and/or Pro in the P1' or P2' position, or a basic residue in the P3 position, are preferentially cleaved by PC2 and not by other enzymes present in the secretory pathway.
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Affiliation(s)
- Hui Pan
- Department of Pharmacology, Albert Einstein College of Medicine, Bronx, New York, USA
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Helwig M, Khorooshi RMH, Tups A, Barrett P, Archer ZA, Exner C, Rozman J, Braulke LJ, Mercer JG, Klingenspor M. PC1/3 and PC2 gene expression and post-translational endoproteolytic pro-opiomelanocortin processing is regulated by photoperiod in the seasonal Siberian hamster (Phodopus sungorus). J Neuroendocrinol 2006; 18:413-25. [PMID: 16684131 DOI: 10.1111/j.1365-2826.2006.01431.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A remarkable feature of the seasonal adaptation displayed by the Siberian hamster (Phodopus sungorus) is the ability to decrease food intake and body weight (by up to 40%) in response to shortening photoperiod. The regulating neuroendocrine systems involved in this adaptation and their neuroanatomical and molecular bases are poorly understood. We investigated the effect of photoperiod on the expression of prohormone convertases 1 (PC1/3) and 2 (PC2) and the endoproteolytic processing of the neuropeptide precursor pro-opiomelanocortin (POMC) within key energy balance regulating centres of the hypothalamus. We compared mRNA levels and protein distribution of PC1/3, PC2, POMC, adrenocorticotrophic hormone (ACTH), alpha-melanocyte-stimulating hormone (MSH), beta-endorphin and orexin-A in selected hypothalamic areas of long day (LD, 16:8 h light:dark), short day (SD, 8:16 h light:dark) and natural-day (ND, photoperiod depending on time of the year) acclimated Siberian hamsters. The gene expression of PC2 was significantly higher within the arcuate nucleus (ARC, P < 0.01) in SD and in ND (versus LD), and is reflected in the day length profile between October and April in the latter. PC1/3 gene expression in the ARC and lateral hypothalamus was higher in ND but not in SD compared to the respective LD controls. The immunoreactivity of PC1/3 cleaved neuropeptide ACTH in the ARC and PC1/3-colocalised orexin-A in the lateral hypothalamus were not affected by photoperiod changes. However, increased levels of PC2 mRNA and protein were associated with higher abundance of the mature neuropeptides alpha-MSH and beta-endorphin (P < 0.01) in SD. This study provides a possible explanation for previous paradoxical findings showing lower food intake in SD associated with decreased POMC mRNA levels. Our results suggest that a major part of neuroendocrine body weight control in seasonal adaptation may be effected by post-translational processing mediated by the prohormone convertases PC1/3 and PC2, in addition to regulation of gene expression of neuropeptide precursors.
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Affiliation(s)
- M Helwig
- Molecular Endocrinology Group, Division of Obesity and Metabolic Health, Rowett Research Institute, Aberdeen Centre for Energy Regulation and Obesity, Aberdeen, UK.
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33
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Hook VYH. Protease pathways in peptide neurotransmission and neurodegenerative diseases. Cell Mol Neurobiol 2006; 26:449-69. [PMID: 16724274 DOI: 10.1007/s10571-006-9047-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2006] [Accepted: 03/03/2006] [Indexed: 02/01/2023]
Abstract
1. Recent research demonstrates the critical importance of neuroproteases for the production of peptide neurotransmitters, and for the production of toxic peptides in major neurodegenerative diseases that include Alzheimer's (AD) and Huntington's diseases. This review describes the strategies utilized to identify the appropriate proteases responsible for producing active peptides for neurotransmission, with application of such approaches for defining protease mechanisms in neurodegenerative diseases. 2. Integration of multidisciplinary approaches in neurobiology, biochemistry, chemistry, proteomics, molecular biology, and genetics has been utilized for neuroprotease studies. These investigations have identified secretory vesicle cathepsin L for the production of the enkephalin opioid peptide neurotransmitter and other neuropeptides. Furthermore, new results using these strategies have identified secretory vesicle cathepsin B for the production of beta-amyloid (Abeta) in the major regulated secretory pathway that provides activity-dependent secretion of Abeta peptides, which accumulate in AD. 3. CNS neuroproteases that participate in peptide neurotransmission and in neurodegenerative diseases represent new candidate drug targets that may be explored in future research for the development of novel therapeutic agents for neurological conditions.
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Affiliation(s)
- Vivian Y H Hook
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Drive MC 0744, La Jolla, CA 92093-0324, USA.
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Drakenberg K, Nikoshkov A, Horváth MC, Fagergren P, Gharibyan A, Saarelainen K, Rahman S, Nylander I, Bakalkin G, Rajs J, Keller E, Hurd YL. Mu opioid receptor A118G polymorphism in association with striatal opioid neuropeptide gene expression in heroin abusers. Proc Natl Acad Sci U S A 2006; 103:7883-8. [PMID: 16682632 PMCID: PMC1472539 DOI: 10.1073/pnas.0600871103] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2006] [Indexed: 01/25/2023] Open
Abstract
Mu opioid receptors are critical for heroin dependence, and A118G SNP of the mu opioid receptor gene (OPRM1) has been linked with heroin abuse. In our population of European Caucasians (n = 118), approximately 90% of 118G allelic carriers were heroin users. Postmortem brain analyses showed the OPRM1 genotype associated with transcription, translation, and processing of the human striatal opioid neuropeptide system. Whereas down-regulation of preproenkephalin and preprodynorphin genes was evident in all heroin users, the effects were exaggerated in 118G subjects and were most prominent for preproenkephalin in the nucleus accumbens shell. Reduced opioid neuropeptide transcription was accompanied by increased dynorphin and enkephalin peptide concentrations exclusively in 118G heroin subjects, suggesting that the peptide processing is associated with the OPRM1 genotype. Abnormal gene expression related to peptide convertase and ubiquitin/proteosome regulation was also evident in heroin users. Taken together, alterations in opioid neuropeptide systems might underlie enhanced opiate abuse vulnerability apparent in 118G individuals.
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Affiliation(s)
| | | | - Monika Cs Horváth
- Sections of *Psychiatry and
- Department of Pharmaceutical Biosciences, Division of Pharmacology, Uppsala University, S-751 24 Uppsala, Sweden; and
| | | | - Anna Gharibyan
- Alcohol and Drug Dependence Research, Department of Clinical Neuroscience, and
| | | | - Sadia Rahman
- Department of Pharmaceutical Biosciences, Division of Pharmacology, Uppsala University, S-751 24 Uppsala, Sweden; and
| | - Ingrid Nylander
- Department of Pharmaceutical Biosciences, Division of Pharmacology, Uppsala University, S-751 24 Uppsala, Sweden; and
| | - Georgy Bakalkin
- Alcohol and Drug Dependence Research, Department of Clinical Neuroscience, and
| | - Jovan Rajs
- Department of Forensic Medicine, Karolinska Institutet, S-171 76 Stockholm, Sweden
| | - Eva Keller
- Department of Forensic Medicine, Semmelweis University, HU 1091, Budapest, Hungary
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Abstract
The nervous system represents a key area for development of novel therapeutic agents for the treatment of neurological and neurodegenerative diseases. Recent research has demonstrated the critical importance of neuroproteases for the production of specific peptide neurotransmitters and for the production of toxic peptides in major neurodegenerative diseases that include Alzheimer, Huntington, and Parkinson diseases. This review illustrates the successful criteria that have allowed identification of proteases responsible for converting protein precursors into active peptide neurotransmitters, consisting of dual cysteine protease and subtilisin-like protease pathways in neuroendocrine cells. These peptide neurotransmitters are critical regulators of neurologic conditions, including analgesia and cognition, and numerous behaviors. Importantly, protease pathways also represent prominent mechanisms in neurodegenerative diseases, especially Alzheimer, Huntington, and Parkinson diseases. Recent studies have identified secretory vesicle cathepsin B as a novel beta-secretase for production of the neurotoxic beta-amyloid (Abeta) peptide of Alzheimer disease. Moreover, inhibition of cathepsin B reduces Abeta peptide levels in brain. These neuroproteases potentially represent new drug targets that should be explored in future pharmaceutical research endeavors for drug discovery.
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Affiliation(s)
- Vivian Y H Hook
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, USA
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36
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Beinfeld MC, Blum A, Vishnuvardhan D, Fanous S, Marchand JE. Cholecystokinin Levels in Prohormone Convertase 2 Knock-out Mouse Brain Regions Reveal a Complex Phenotype of Region-specific Alterations. J Biol Chem 2005; 280:38410-5. [PMID: 16174778 DOI: 10.1074/jbc.m500055200] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Prohormone convertase 2 is widely co-localized with cholecystokinin in rodent brain. To examine its role in cholecystokinin processing, cholecystokinin levels were measured in dissected brain regions from prohormone convertase 2 knock-out mice. Cholecystokinin levels were lower in hippocampus, septum, thalamus, mesencephalon, and pons in knock-out mice than wild-type mice. In cerebral cortex, cortex-related structures and olfactory bulb, cholecystokinin levels were higher than wild type. Female mice were more affected by the loss of prohormone convertase 2 than male mice. The decrease in cholecystokinin levels in these brain regions shows that prohormone convertase 2 is important for cholecystokinin processing. Quantitative polymerase chain reaction measurements were performed to examine the relationship between peptide levels and cholecystokinin and enzyme expression. They revealed that cholecystokinin and prohormone convertase 1 mRNA levels in cerebral cortex and olfactory bulb were actually lower in knock-out than wild type, whereas their expression in other brain regions of knock-out mouse brain was the same as wild type. Female mice frequently had higher expression of cholecystokinin and prohormone convertase 1, 2, and 5 mRNA than male mice. The loss of prohormone convertase 2 alters CCK processing in specific brain regions. This loss also appears to trigger compensatory mechanisms in cerebral cortex and olfactory bulb that produce elevated levels of cholecystokinin but do not involve increased expression of cholecystokinin, prohormone convertase 1 or 5 mRNA.
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Affiliation(s)
- Margery C Beinfeld
- Departments of Pharmacology and Experimental Therapeutics, Tufts University School of Medicine, Boston, Massachusetts 02111, USA.
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Hook V, Yasothornsrikul S, Greenbaum D, Medzihradszky KF, Troutner K, Toneff T, Bundey R, Logrinova A, Reinheckel T, Peters C, Bogyo M. Cathepsin L and Arg/Lys aminopeptidase: a distinct prohormone processing pathway for the biosynthesis of peptide neurotransmitters and hormones. Biol Chem 2005; 385:473-80. [PMID: 15255178 DOI: 10.1515/bc.2004.055] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Peptide neurotransmitters and hormones are synthesized as protein precursors that require proteolytic processing to generate smaller, biologically active peptides that are secreted to mediate neurotransmission and hormone actions. Neuropeptides within their precursors are typically flanked by pairs of basic residues, as well as by monobasic residues. In this review, evidence for secretory vesicle cathepsin L and Arg/Lys aminopeptidase as a distinct proteolytic pathway for processing the prohormone proenkephalin is presented. Cleavage of prohormone processing sites by secretory vesicle cathepsin L occurs at the NH2-terminal side of dibasic residues, as well as between the dibasic residues, resulting in peptide intermediates with Arg or Lys extensions at their NH2-termini. A subsequent Arg/Lys aminopeptidase step is then required to remove NH2-terminal basic residues to generate the final enkephalin neuropeptide. The cathepsin L and Arg/Lys aminopeptidase prohormone processing pathway is distinct from the proteolytic pathway mediated by the subtilisin-like prohormone convertases 1/3 and 2 (PC1/3 and PC2) with carboxypeptidase E/H. Differences in specific cleavage sites at paired basic residue sites distinguish these two pathways. These two proteolytic pathways demonstrate the increasing complexity of regulatory mechanisms for the production of peptide neurotransmitters and hormones.
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Affiliation(s)
- Vivian Hook
- Buck Institute for Age Research, Novato, CA 94945, USA.
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Weitemier AZ, Tsivkovskaia NO, Ryabinin AE. Urocortin 1 distribution in mouse brain is strain-dependent. Neuroscience 2005; 132:729-40. [PMID: 15837134 DOI: 10.1016/j.neuroscience.2004.12.047] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/31/2004] [Indexed: 11/29/2022]
Abstract
Urocortin 1 has been implicated in a number of specific behaviors, which include energy balance, stress reactivity and ethanol consumption. To elucidate genetically influenced differences in the mouse urocortin 1 system, we performed immunohistochemical characterization of urocortin 1 distribution in C57BL/6J and DBA/2J mouse brain. Urocortin 1 analysis reveals strain-dependent differences in distribution of urocortin 1 immunoreactive neurons and neuronal fibers. In both strains, the highest number of urocortin 1-positive neurons was observed in the Edinger-Westphal nucleus and lateral superior olive. Urocortin 1-positive neurons were detected in the dorsal nucleus of the lateral lemniscus of DBA/2J mice, but were absent in the C57BL/6J strain. Differences in urocortin 1 fibers were detected in many areas throughout the brain, and were most apparent in the septal areas, thalamic areas, several midbrain regions, and medulla. Strain-dependent distribution of urocortin 1-containing cells and fibers suggests that differences in this neuropeptide system may underlie differences in behavior and physiological responses between these strains. Further, we found that in both mouse strains, urocortin 1 in the Edinger-Westphal nucleus and choline acetyltransferase are not coexpressed. We show that the urocortin 1-positive neurons of this brain area form a separate population of cells that we propose to be called the non-preganglionic Edinger-Westphal nucleus.
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Affiliation(s)
- A Z Weitemier
- Department of Behavioral Neuroscience, Orego Health and Science University, Portland, OR 97239, USA.
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Savontaus E, Breen TL, Kim A, Yang LM, Chua SC, Wardlaw SL. Metabolic effects of transgenic melanocyte-stimulating hormone overexpression in lean and obese mice. Endocrinology 2004; 145:3881-91. [PMID: 15117873 DOI: 10.1210/en.2004-0263] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The proopiomelanocortin-derived peptide, alpha-MSH, inhibits feeding via melanocortin receptors in the hypothalamus and genetic defects inactivating the melanocortin system have been shown to lead to obesity in experimental animals and humans. To determine whether long-term melanocortinergic activation has significant effects on body weight and composition and insulin sensitivity, transgenic mice overexpressing N-terminal proopiomelanocortin, including alpha- and gamma(3)-MSH, under the control of the cytomegalovirus-promoter were generated. The transgene was expressed in multiple tissues including the hypothalamus, in which both alpha-MSH and gamma(3)-MSH levels were increased approximately 2-fold, compared with wild-type controls. Transgene homozygous mice were also crossed with obese leptin receptor-deficient db(3J) and obese yellow A(y) mice. MSH overexpression led to uniform, dose- dependent darkening of coat color. MSH overexpression reduced weight gain and adiposity and improved glucose tolerance in lean male mice. In female transgenic mice, there was no significant effect on body weight, but there was a significant decrease in insulin levels. Obesity was attenuated in obese db(3J)/db(3J) male and female mice, but there was no improvement in glucose metabolism. In contrast, the MSH transgene improved glucose tolerance in male A(y) mice. These results support the hypothesis that long-term melanocortinergic activation could serve as a potential strategy for anti-obesity and/or antidiabetic therapy.
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Affiliation(s)
- Eriika Savontaus
- Department of Medicine and Pediatrics, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA
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40
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Yasothornsrikul S, Greenbaum D, Medzihradszky KF, Toneff T, Bundey R, Miller R, Schilling B, Petermann I, Dehnert J, Logvinova A, Goldsmith P, Neveu JM, Lane WS, Gibson B, Reinheckel T, Peters C, Bogyo M, Hook V. Cathepsin L in secretory vesicles functions as a prohormone-processing enzyme for production of the enkephalin peptide neurotransmitter. Proc Natl Acad Sci U S A 2003; 100:9590-5. [PMID: 12869695 PMCID: PMC170962 DOI: 10.1073/pnas.1531542100] [Citation(s) in RCA: 174] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Multistep proteolytic mechanisms are essential for converting proprotein precursors into active peptide neurotransmitters and hormones. Cysteine proteases have been implicated in the processing of proenkephalin and other neuropeptide precursors. Although the papain family of cysteine proteases has been considered the primary proteases of the lysosomal degradation pathway, more recent studies indicate that functions of these enzymes are linked to specific biological processes. However, few protein substrates have been described for members of this family. We show here that secretory vesicle cathepsin L is the responsible cysteine protease of chromaffin granules for converting proenkephalin to the active enkephalin peptide neurotransmitter. The cysteine protease activity was identified as cathepsin L by affinity labeling with an activity-based probe for cysteine proteases followed by mass spectrometry for peptide sequencing. Production of [Met]enkephalin by cathepsin L occurred by proteolytic processing at dibasic and monobasic prohormone-processing sites. Cellular studies showed the colocalization of cathepsin L with [Met]enkephalin in secretory vesicles of neuroendocrine chromaffin cells by immunofluorescent confocal and immunoelectron microscopy. Functional localization of cathepsin L to the regulated secretory pathway was demonstrated by its cosecretion with [Met]enkephalin. Finally, in cathepsin L gene knockout mice, [Met]enkephalin levels in brain were reduced significantly; this occurred with an increase in the relative amounts of enkephalin precursor. These findings indicate a previously uncharacterized biological role for secretory vesicle cathepsin L in the production of [Met]enkephalin, an endogenous peptide neurotransmitter.
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