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Vargas-Pinilla P, S Oliveira Fam B, Medina Tavares G, Lima T, Landau L, Paré P, de Cássia Aleixo Tostes R, Pissinatti A, Falótico T, Costa-Neto C, Maestri R, Bortolini MC. From molecular variations to behavioral adaptations: Unveiling adaptive epistasis in primate oxytocin system. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2024:e24947. [PMID: 38783700 DOI: 10.1002/ajpa.24947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 04/12/2024] [Accepted: 04/24/2024] [Indexed: 05/25/2024]
Abstract
OBJECTIVE Our primary objective was to investigate the variability of oxytocin (OT) and the GAMEN binding motif within the LNPEP oxytocinase in primates. MATERIALS AND METHODS We sequenced the LNPEP segment encompassing the GAMEN motif in 34 Platyrrhini species, with 21 of them also sequenced for the OT gene. Our dataset was supplemented with primate sequences of LNPEP, OT, and the oxytocin receptor (OTR) sourced from public databases. Evolutionary analysis and coevolution predictions were made followed by the macroevolution analysis of relevant amino acids associated with phenotypic traits, such as mating systems, parental care, and litter size. To account for phylogenetic structure, we utilized two distinct statistical tests. Additionally, we calculated binding energies focusing on the interaction between Callithtrix jacchus VAMEN and Pro8OT. RESULTS We identified two novel motifs (AAMEN and VAMEN), challenging the current knowledge of motif conservation in placental mammals. Coevolution analysis demonstrated a correlation between GAMEN, AAMEN, and VAMEN and their corresponding OTs and OTRs. Callithrix jacchus exhibited a higher binding energy between VAMEN and Pro8OT than orthologous molecules found in humans (GAMEN and Leu8OT). DISCUSSION The coevolution of AAMEN and VAMEN with their corresponding OTs and OTRs suggests a functional relationship that could have contributed to specific reproductive and adaptive behaviors, including paternal care, social monogamy, and twin births, prominent traits in Cebidae species, such as marmosets and tamarins. Our findings underscore the coevolution of taxon-specific amino acids among the three studied molecules, shedding light on the oxytocinergic system as an adaptive epistatic repertoire in primates.
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Affiliation(s)
- Pedro Vargas-Pinilla
- Laboratory of Human and Molecular Evolution, Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Departamento de Farmacologia, Faculdade de Medicina, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Bibiana S Oliveira Fam
- Laboratory of Human and Molecular Evolution, Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Laboratório de Medicina Genômica, Centro de Pesquisa Experimental (CPE), Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Gustavo Medina Tavares
- Laboratory of Human and Molecular Evolution, Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Thaynara Lima
- Laboratory of Human and Molecular Evolution, Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Luane Landau
- Laboratory of Human and Molecular Evolution, Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Department of Biological Sciences, University at Buffalo, Buffalo, New York, USA
| | - Pâmela Paré
- Laboratory of Human and Molecular Evolution, Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | | | | | - Tiago Falótico
- Escola de Artes, Ciências e Humanidades, Universidade de São Paulo, São Paulo, Brazil
| | - Cláudio Costa-Neto
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Renan Maestri
- Laboratório de Ecomorfologia e Macroevolução, Departamento de Ecologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Maria Cátira Bortolini
- Laboratory of Human and Molecular Evolution, Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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Engen K, Lundbäck T, Yadav A, Puthiyaparambath S, Rosenström U, Gising J, Jenmalm-Jensen A, Hallberg M, Larhed M. Inhibition of Insulin-Regulated Aminopeptidase by Imidazo [1,5-α]pyridines-Synthesis and Evaluation. Int J Mol Sci 2024; 25:2516. [PMID: 38473764 DOI: 10.3390/ijms25052516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 02/15/2024] [Accepted: 02/16/2024] [Indexed: 03/14/2024] Open
Abstract
Inhibition of insulin-regulated aminopeptidase (IRAP) has been shown to improve cognitive functions in several animal models. Recently, we performed a screening campaign of approximately 10,000 compounds, identifying novel small-molecule-based compounds acting as inhibitors of the enzymatic activity of IRAP. Here we report on the chemical synthesis, structure-activity relationships (SAR) and initial characterization of physicochemical properties of a series of 48 imidazo [1,5-α]pyridine-based inhibitors, including delineation of their mode of action as non-competitive inhibitors with a small L-leucine-based IRAP substrate. The best compound displays an IC50 value of 1.0 µM. We elucidate the importance of two chiral sites in these molecules and find they have little impact on the compound's metabolic stability or physicochemical properties. The carbonyl group of a central urea moiety was initially believed to mimic substrate binding to a catalytically important Zn2+ ion in the active site, although the plausibility of this binding hypothesis is challenged by observation of excellent selectivity versus the closely related aminopeptidase N (APN). Taken together with the non-competitive inhibition pattern, we also consider an alternative model of allosteric binding.
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Affiliation(s)
- Karin Engen
- Department of Medicinal Chemistry, Uppsala University, BMC, P.O. Box 574, SE-751 23 Uppsala, Sweden
| | - Thomas Lundbäck
- Chemical Biology Consortium Sweden (CBCS), Science for Life Laboratory, Department of Medical Biochemistry and Biophysics, Division of Chemical Biology and Genome Engineering, Karolinska Institutet, Tomtebodavägen 23A, SE-171 65 Solna, Sweden
- Mechanistic & Structural Biology, Discovery Sciences, R&D, AstraZeneca, SE-431 83 Mölndal, Sweden
| | - Anubha Yadav
- The Beijer Laboratory, Science for Life Laboratory, Department of Medicinal Chemistry, Uppsala University, BMC, P.O. Box 574, SE-751 23 Uppsala, Sweden
| | - Sharathna Puthiyaparambath
- The Beijer Laboratory, Science for Life Laboratory, Department of Medicinal Chemistry, Uppsala University, BMC, P.O. Box 574, SE-751 23 Uppsala, Sweden
| | - Ulrika Rosenström
- Department of Medicinal Chemistry, Uppsala University, BMC, P.O. Box 574, SE-751 23 Uppsala, Sweden
| | - Johan Gising
- The Beijer Laboratory, Science for Life Laboratory, Department of Medicinal Chemistry, Uppsala University, BMC, P.O. Box 574, SE-751 23 Uppsala, Sweden
| | - Annika Jenmalm-Jensen
- Chemical Biology Consortium Sweden (CBCS), Science for Life Laboratory, Department of Medical Biochemistry and Biophysics, Division of Chemical Biology and Genome Engineering, Karolinska Institutet, Tomtebodavägen 23A, SE-171 65 Solna, Sweden
| | - Mathias Hallberg
- The Beijer Laboratory, Department of Pharmaceutical Biosciences, Neuropharmacology and Addiction Research, Uppsala University, BMC, P.O. Box 591, SE-751 24 Uppsala, Sweden
| | - Mats Larhed
- The Beijer Laboratory, Science for Life Laboratory, Department of Medicinal Chemistry, Uppsala University, BMC, P.O. Box 574, SE-751 23 Uppsala, Sweden
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Vear A, Thalmann C, Youngs K, Hannan N, Gaspari T, Chai SY. Development of a sandwich ELISA to detect circulating, soluble IRAP as a potential disease biomarker. Sci Rep 2023; 13:17565. [PMID: 38001104 PMCID: PMC10673851 DOI: 10.1038/s41598-023-44038-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 10/03/2023] [Indexed: 11/26/2023] Open
Abstract
There is growing interest in the use of the enzyme, insulin regulated aminopeptidase (IRAP), as a biomarker for conditions such as cardio-metabolic diseases and ischemic stroke, with upregulation in its tissue expression in these conditions. However, quantification of circulating IRAP has been hampered by difficulties in detecting release of the truncated, soluble form of this enzyme into the blood stream. The current study aimed to develop a sandwich ELISA using novel antibodies directed towards the soluble portion of IRAP (sIRAP), to improve accuracy in detection and quantification of low levels of sIRAP in plasma. A series of novel anti-IRAP antibodies were developed and found to be highly specific for sIRAP in Western blots. A sandwich ELISA was then optimised using two distinct antibody combinations to detect sIRAP in the low nanogram range (16-500 ng/ml) with a sensitivity of 9 ng/ml and intra-assay variability < 10%. Importantly, the clinical validity of the ELISA was verified by the detection of significant increases in the levels of sIRAP throughout gestation in plasma samples from pregnant women. The specific and sensitive sandwich ELISA described in this study has the potential to advance the development of IRAP as a biomarker for certain diseases.
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Affiliation(s)
- Anika Vear
- Department of Physiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Claudia Thalmann
- Department of Physiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Kristina Youngs
- Department of Physiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Natalie Hannan
- Department of Obstetrics and Gynaecology, University of Melbourne, Heidelberg, VIC, 3084, Australia
- Mercy Perinatal, Mercy Hospital for Women, Heidelberg, VIC, 3084, Australia
| | - Tracey Gaspari
- Department of Pharmacology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Siew Yeen Chai
- Department of Physiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia.
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Sui L, Guo HC. Enhanced recombinant expression and purification of human IRAP for biochemical and crystallography studies. Biochem Biophys Rep 2021; 27:101042. [PMID: 34169156 PMCID: PMC8207215 DOI: 10.1016/j.bbrep.2021.101042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 06/01/2021] [Accepted: 06/02/2021] [Indexed: 11/25/2022] Open
Abstract
Insulin-regulated aminopeptidase (IRAP) in humans is a membrane bound enzyme that has multiple functions. It was first described as a companion protein of the insulin-responsive glucose transporter, Glut4, in specialized vesicles. The protein has subsequently been shown to be identical to the oxytocinase/aminopeptidase or the angiotensin IV (Ang IV) receptor (AT4 receptor). Some AT4 ligand peptides, such as Ang IV and LVV-hemorphin-7, have been shown to act as IRAP inhibitors that exert memory-enhancing properties. As such IRAP has been a target for developing cognitive enhancers. To facilitate detailed mechanistic studies of IRAP catalysis and inhibition, and to pave the way for biophysical and structural studies of IRAP in complex with peptide inhibitors, we report here an optimized expression and purification system using High Five insect cells. We also report biochemical characterizations of the purified recombinant IRAP with a standard aminopeptidase substrate and an optimized IRAP peptide inhibitor with a Ki of 98 nM.
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Key Words
- AT4, Ang IV receptor
- Ang IV, angiotensin IV
- Cognitive enhancers
- Crystallization
- ERAP, endoplasmic reticulum aminopeptidase
- Expression and purification
- IEX, ion exchange chromatography
- IMAC, immobilized metal ion affinity chromatography
- IRAP, insulin-regulated aminopeptidase
- Insulin-regulated aminopeptidase (IRAP)
- L-AMC, leucine 7-amido-4-methylcoumarin
- LVV-H7, LVV-hemorphin-7
- MHC-I, major histocompatibility complex class I
- Peptide inhibitor
- SEC, size exclusion chromatography
- Substrate affinity
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Affiliation(s)
- Lufei Sui
- Department of Biological Sciences, University of Massachusetts Lowell, 1 University Avenue, Lowell, MA, 01854, USA
| | - Hwai-Chen Guo
- Department of Biological Sciences, University of Massachusetts Lowell, 1 University Avenue, Lowell, MA, 01854, USA
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Insulin-regulated aminopeptidase deficiency impairs cardiovascular adaptations and placental development during pregnancy. Clin Sci (Lond) 2021; 134:3213-3228. [PMID: 33252660 PMCID: PMC7733041 DOI: 10.1042/cs20201233] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/09/2020] [Accepted: 11/30/2020] [Indexed: 01/22/2023]
Abstract
Insulin-regulated aminopeptidase (IRAP), an enzyme that cleaves vasoactive peptides including oxytocin and vasopressin, is suggested to play a role in pregnancy and the onset of preeclampsia. Our aim was to examine the contribution of IRAP to arterial pressure regulation and placental development during pregnancy in mice. Mean arterial pressure and heart rate were measured via radiotelemetry in 12-week-old female wild-type and IRAP knockout mice. Females were time-mated with males of the same genotype. Placentae were collected at embryonic day 18.5 for histological analysis. Basal heart rate was ∼40 bpm lower in IRAP knockout females compared with wild-type females. The increase in heart rate across gestation was greater in IRAP knockout females than wild-type females. Neither basal nor gestational mean arterial pressure was different between wildtype and IRAP knockout females. Urine output and water intake of IRAP knockout mice were ∼45% less than wild-type mice at late gestation. IRAP deficiency had no effect on fetal weight. Morphological assessment of placentae revealed that IRAP deficiency was associated with reduced labyrinth surface area and accumulation of glycogen in the junctional zone. Our data demonstrate that IRAP deficiency alters maternal fluid handling and impairs placental labyrinth expansion at late gestation, indicating that IRAP contributes to the normal adaptions to pregnancy.
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Hallberg M, Larhed M. From Angiotensin IV to Small Peptidemimetics Inhibiting Insulin-Regulated Aminopeptidase. Front Pharmacol 2020; 11:590855. [PMID: 33178027 PMCID: PMC7593869 DOI: 10.3389/fphar.2020.590855] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 09/18/2020] [Indexed: 12/26/2022] Open
Abstract
It was reported three decades ago that intracerebroventricular injection of angiotensin IV (Ang IV, Val-Tyr-Ile-His-Pro-Phe) improved memory and learning in the rat. There are several explanations for these positive effects of the hexapeptide and related analogues on cognition available in the literature. In 2001, it was proposed that the insulin-regulated aminopeptidase (IRAP) is a main target for Ang IV and that Ang IV serves as an inhibitor of the enzyme. The focus of this review is the efforts to stepwise transform the hexapeptide into more drug-like Ang IV peptidemimetics serving as IRAP inhibitors. Moreover, the discovery of IRAP inhibitors by virtual and substance library screening and direct design applying knowledge of the structure of IRAP and of related enzymes is briefly presented.
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Affiliation(s)
- Mathias Hallberg
- The Beijer Laboratory, Division of Biological Research on Drug Dependence, Department of Pharmaceutical Biosciences, BMC, Uppsala University, Uppsala, Sweden
| | - Mats Larhed
- Department of Medicinal Chemistry, Science for Life Laboratory, BMC, Uppsala University, Uppsala, Sweden
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7
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Goto Y, Nakamura TJ, Ogawa K, Hattori A, Tsujimoto M. Reciprocal Expression Patterns of Placental Leucine Aminopeptidase/Insulin-Regulated Aminopeptidase and Vasopressin in the Murine Brain. Front Mol Biosci 2020; 7:168. [PMID: 32793633 PMCID: PMC7393517 DOI: 10.3389/fmolb.2020.00168] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 07/01/2020] [Indexed: 01/23/2023] Open
Abstract
Placental leucine aminopeptidase/insulin-regulated aminopeptidase (P-LAP/IRAP) regulates vasopressin and oxytocin levels in the brain and peripheral tissues by controlled degradation of these peptides. In this study, we determined the relationship between P-LAP/IRAP and vasopressin levels in subregions of the murine brain. P-LAP/IRAP expression was observed in almost all brain regions. The expression patterns of P-LAP/IRAP and vasopressin indicated that cells expressing one of these protein/peptide were distinct from those expressing the other, although there was significant overlap between the expression regions. In addition, we found reciprocal diurnal rhythm patterns in P-LAP/IRAP and arginine vasopressin (AVP) expression in the hippocampus and pituitary gland. Further, synchronously cultured PC12 cells on treatment with nerve growth factor (NGF) showed circadian expression patterns of P-LAP/IRAP and enzymatic activity during 24 h of incubation. Considering that vasopressin is one of the most efficient peptide substrates of P-LAP/IRAP, these results suggest a possible feedback loop between P-LAP/IRAP and vasopressin expression, that regulates the function of these substrate peptides of the enzyme via translocation of P-LAP/IRAP from intracellular vesicles to the plasma membrane in brain cells. These findings provide novel insights into the functions of P-LAP/IRAP in the brain and suggest the involvement of these peptides in modulation of brain AVP functions in hyperosmolality, memory, learning, and circadian rhythm.
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Affiliation(s)
- Yoshikuni Goto
- Faculty of Pharmaceutical Sciences, Teikyo Heisei University, Nakano, Japan
| | - Takahiro J Nakamura
- Laboratory of Animal Physiology, School of Agriculture, Meiji University, Kawasaki, Japan
| | - Kenji Ogawa
- Laboratory of Veterinary Epizootiology, Department of Veterinary Medicine, Nihon University, Fujisawa, Japan
| | - Akira Hattori
- Department of System Chemotherapy and Molecular Sciences, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Masafumi Tsujimoto
- Faculty of Pharmaceutical Sciences, Teikyo Heisei University, Nakano, Japan
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Engen K, Vanga SR, Lundbäck T, Agalo F, Konda V, Jensen AJ, Åqvist J, Gutiérrez-de-Terán H, Hallberg M, Larhed M, Rosenström U. Synthesis, Evaluation and Proposed Binding Pose of Substituted Spiro-Oxindole Dihydroquinazolinones as IRAP Inhibitors. ChemistryOpen 2020; 9:325-337. [PMID: 32154052 PMCID: PMC7050655 DOI: 10.1002/open.201900344] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 01/23/2020] [Indexed: 12/13/2022] Open
Abstract
Insulin-regulated aminopeptidase (IRAP) is a new potential macromolecular target for drugs aimed for treatment of cognitive disorders. Inhibition of IRAP by angiotensin IV (Ang IV) improves the memory and learning in rats. The majority of the known IRAP inhibitors are peptidic in character and suffer from poor pharmacokinetic properties. Herein, we present a series of small non-peptide IRAP inhibitors derived from a spiro-oxindole dihydroquinazolinone screening hit (pIC50 5.8). The compounds were synthesized either by a simple microwave (MW)-promoted three-component reaction, or by a two-step one-pot procedure. For decoration of the oxindole ring system, rapid MW-assisted Suzuki-Miyaura cross-couplings (1 min) were performed. A small improvement of potency (pIC50 6.6 for the most potent compound) and an increased solubility could be achieved. As deduced from computational modelling and MD simulations it is proposed that the S-configuration of the spiro-oxindole dihydroquinazolinones accounts for the inhibition of IRAP.
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Affiliation(s)
- Karin Engen
- Department of Medicinal Chemistry Uppsala University SE-751 23 Uppsala SWEDEN
| | - Sudarsana Reddy Vanga
- Department of Cell and Molecular Biology Uppsala University SE-751 23 Uppsala SWEDEN
| | - Thomas Lundbäck
- Chemical Biology Consortium Sweden, Science for Life Laboratory, Department of Medical Biochemistry and Biophysics Karolinska Institutet SE-171 65 Solna SWEDEN
- Mechanistic Biology & Profiling, Discovery Sciences, R&D AstraZeneca SE-431 83 Göteborg SWEDEN
| | - Faith Agalo
- Department of Medicinal Chemistry Uppsala University SE-751 23 Uppsala SWEDEN
| | - Vivek Konda
- Department of Medicinal Chemistry Uppsala University SE-751 23 Uppsala SWEDEN
| | - Annika Jenmalm Jensen
- Chemical Biology Consortium Sweden, Science for Life Laboratory, Department of Medical Biochemistry and Biophysics Karolinska Institutet SE-171 65 Solna SWEDEN
| | - Johan Åqvist
- Department of Cell and Molecular Biology Uppsala University SE-751 23 Uppsala SWEDEN
| | - Hugo Gutiérrez-de-Terán
- Science for Life Laboratory, Department of Cell and Molecular Biology Uppsala University SE-751 23 Uppsala SWEDEN
| | - Mathias Hallberg
- The Beijer Laboratory, Department of Pharmaceutical Biosciences Uppsala University SE-751 23 Uppsala SWEDEN
| | - Mats Larhed
- Science for Life Laboratory, Department of Medicinal Chemistry Uppsala University SE-751 23 Uppsala SWEDEN
| | - Ulrika Rosenström
- Department of Medicinal Chemistry Uppsala University SE-751 23 Uppsala SWEDEN
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Burns P, Bowditch J, McFadyen J, Loiacono R, Albiston AL, Pham V, Chai SY. Social behaviour is altered in the insulin-regulated aminopeptidase knockout mouse. Behav Brain Res 2019; 376:112150. [DOI: 10.1016/j.bbr.2019.112150] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 08/06/2019] [Accepted: 08/12/2019] [Indexed: 11/29/2022]
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da Cruz KR, Ianzer D, Turones LC, Reis LL, Camargo-Silva G, Mendonça MM, da Silva ES, Pedrino GR, de Castro CH, Costa EA, Xavier CH. Behavioral effects evoked by the beta globin-derived nonapeptide LVV-H6. Peptides 2019; 115:59-68. [PMID: 30890354 DOI: 10.1016/j.peptides.2019.03.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 02/04/2019] [Accepted: 03/12/2019] [Indexed: 02/05/2023]
Abstract
LVV-hemorphin-6 (LVV-h6) is bioactive peptide and is a product of the degradation of hemoglobin. Since LVV-h6 effects are possibly mediated by opioid or AT4/IRAP receptors, we hypothesized that LVV-h6 would modify behavior. We evaluated whether LVV-h6 affects: i) anxiety-like behavior and locomotion; ii) depression-like behavior; iii) cardiovascular and neuroendocrine reactivity to emotional stress. Male Wistar rats ( ± 300 g) received LVV-h6 (153 nmol/kg i.p.) or vehicle (NaCl 0.9% i.p.). We used: i) open field (OF) test for locomotion; ii) elevated plus maze (EPM) for anxiety-like behavior; iii) forced swimming test (FST) for depression-like behavior and iv) air jet for cardiovascular and neuroendocrine reactivity to stress. Diazepam (2 mg/kg i.p.) and imipramine (15 mg/kg i.p.) were used as positive control for EPM and FST, respectively. To evaluate the LVV-h6 mechanisms, we used: the antagonist of oxytocin (OT) receptors (atosiban - ATS 1 and 0.1 mg/kg i.p.); the inhibitor of tyrosine hydroxylase (Alpha-methyl-p-tyrosine - AMPT 200 mg/kg i.p.) to investigate the involvement of catecholaminergic paths; and the antagonist of opioid receptors (naltrexone - NTX 0.3 mg/kg s.c.). We found that LVV-h6: i) evoked anxiolytic-like effect; ii) evoked antidepressant-like effect in the FST; and iii) did not change the locomotion, neuroendocrine and cardiovascular responses to stress. The LVV-h6 anxiolytic-like effect was not reverted by ATS and AMPT. However, the antidepressant effects were reverted only by NTX. Hence, our findings demonstrate that LVV-h6 modulates anxiety-like behavior by routes that are not oxytocinergic, catecholaminergic or opioid. The antidepressant-like effects of LVV-h6 rely on opioid pathways.
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Affiliation(s)
- Kellen Rosa da Cruz
- Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiânia, GO, Brazil
| | - Danielle Ianzer
- Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiânia, GO, Brazil
| | - Larissa Córdova Turones
- Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiânia, GO, Brazil
| | - Lilian Liz Reis
- Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiânia, GO, Brazil
| | - Gabriel Camargo-Silva
- Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiânia, GO, Brazil
| | - Michelle Mendanha Mendonça
- Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiânia, GO, Brazil
| | - Elder Sales da Silva
- Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiânia, GO, Brazil
| | - Gustavo Rodrigues Pedrino
- Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiânia, GO, Brazil
| | - Carlos Henrique de Castro
- Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiânia, GO, Brazil
| | - Elson Alves Costa
- Department of Pharmacology, Institute of Biological Sciences, Federal University of Goiás, Goiânia, GO, Brazil
| | - Carlos H Xavier
- Department of Physiological Sciences, Institute of Biological Sciences, Federal University of Goiás, Goiânia, GO, Brazil.
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Lema SC, Washburn EH, Crowley ME, Carvalho PG, Egelston JN, McCormick SD. Evidence for a role of arginine vasotocin receptors in the gill during salinity acclimation by a euryhaline teleost fish. Am J Physiol Regul Integr Comp Physiol 2019; 316:R735-R750. [PMID: 30916577 DOI: 10.1152/ajpregu.00328.2018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The nonapeptide arginine vasotocin (AVT) regulates osmotic balance in teleost fishes, but its mechanisms of action are not fully understood. Recently, it was discovered that nonapeptide receptors in teleost fishes are differentiated into two V1a-type, several V2-type, and two isotocin (IT) receptors, but it remains unclear which receptors mediate AVT's effects on gill osmoregulation. Here, we examined the role of nonapeptide receptors in the gill of the euryhaline Amargosa pupfish (Cyprinodon nevadensis amargosae) during osmotic acclimation. Transcripts for the teleost V1a-type receptor v1a2 were upregulated over fourfold in gill 24 h after transferring pupfish from 7.5 ppt to seawater (35 ppt) or hypersaline (55 ppt) conditions and downregulated after transfer to freshwater (0.3 ppt). Gill transcripts for the nonapeptide degradation enzyme leucyl-cystinyl aminopeptidase (LNPEP) also increased in fish acclimating to 35 ppt. To test whether the effects of AVT on the gill might be mediated by a V1a-type receptor, we administered AVT or a V1-type receptor antagonist (Manning compound) intraperitoneally to pupfish before transfer to 0.4 ppt or 35 ppt. Pupfish transferred to 35 ppt exhibited elevated gill mRNA abundance for cystic fibrosis transmembrane conductance regulator (cftr), but that upregulation diminished under V1-receptor inhibition. AVT inhibited the increase in gill Na+/Cl- cotransporter 2 (ncc2) transcript abundance that occurs following transfer to hypoosmotic environments, whereas V1-type receptor antagonism increased ncc2 mRNAs even without a change in salinity. These findings indicate that AVT acts via a V1-type receptor to regulate gill Cl- transport by inhibiting Cl- uptake and facilitating Cl- secretion during seawater acclimation.
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Affiliation(s)
- Sean C Lema
- Biological Sciences Department, Center for Coastal Marine Sciences, California Polytechnic State University , San Luis Obispo, California
| | - Elsie H Washburn
- Biological Sciences Department, Center for Coastal Marine Sciences, California Polytechnic State University , San Luis Obispo, California
| | - Mary E Crowley
- Biological Sciences Department, Center for Coastal Marine Sciences, California Polytechnic State University , San Luis Obispo, California
| | - Paul G Carvalho
- Biological Sciences Department, Center for Coastal Marine Sciences, California Polytechnic State University , San Luis Obispo, California
| | - Jennifer N Egelston
- Biological Sciences Department, Center for Coastal Marine Sciences, California Polytechnic State University , San Luis Obispo, California
| | - Stephen D McCormick
- United States Geological Survey, Leetown Science Center, Conte Anadromous Fish Research Laboratory, Turners Falls, Massachusetts
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12
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Abrahão MV, Dos Santos NFT, Kuwabara WMT, do Amaral FG, do Carmo Buonfiglio D, Peres R, Vendrame RFA, Flávio da Silveira P, Cipolla-Neto J, Baltatu OC, Afeche SC. Identification of insulin-regulated aminopeptidase (IRAP) in the rat pineal gland and the modulation of melatonin synthesis by angiotensin IV. Brain Res 2018; 1704:40-46. [PMID: 30222958 DOI: 10.1016/j.brainres.2018.09.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 08/29/2018] [Accepted: 09/11/2018] [Indexed: 02/06/2023]
Abstract
A local renin-angiotensin system (RAS) has been postulated in the pineal gland. In addition to angiotensin II (Ang II), other active metabolites have been described. In this study, we aimed to investigate a role for Ang IV in melatonin synthesis and the presence of its proposed (IRAP)/AT4 receptor (insulin-regulated aminopeptidase) in the pineal gland. The effect of Ang IV on melatonin synthesis was investigated in vitro using isolated pinealocytes. IRAP protein expression and activity were evaluated by Western blot and fluorimetry using Leu-4Me-β-naphthylamide as a substrate. Melatonin was analyzed by HPLC, calcium content by confocal microscopy and cAMP by immunoassay. Ang IV significantly augmented the NE-induced melatonin synthesis to a similar degree as that achieved by Ang II. This Ang IV effect in pinealocytes appears to be mediated by an increase in the intracellular calcium content but not by cAMP. The (IRAP)/AT4 expression and activity were identified in the pineal gland, which were significantly higher in membrane fractions than in soluble fractions. Ang IV significantly reduced IRAP activity in the pineal membrane fractions. The main findings of the present study are as follows: (1) Ang IV potentiates NE-stimulated melatonin production in pinealocytes, (2) the (IRAP)/AT4 receptor is present in the rat pineal gland, and (3) Ang IV inhibits IRAP activity and increases pinealocytes [Ca2+]i. We conclude that Ang IV is an important component of RAS and modulates melatonin synthesis in the rat pineal gland.
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Affiliation(s)
| | | | - Wilson Mitsuo Tatagiba Kuwabara
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, 05508-900 São Paulo, SP, Brazil
| | - Fernanda Gaspar do Amaral
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, 05508-900 São Paulo, SP, Brazil; Department of Physiology, Federal University of São Paulo, 04023-901 São Paulo, SP, Brazil
| | - Daniella do Carmo Buonfiglio
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, 05508-900 São Paulo, SP, Brazil
| | - Rafael Peres
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, 05508-900 São Paulo, SP, Brazil
| | | | | | - José Cipolla-Neto
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, 05508-900 São Paulo, SP, Brazil
| | - Ovidiu Constantin Baltatu
- Center of Innovation, Technology and Education (CITE), Anhembi Morumbi University-Laureate International Universities, 12247-016 São José dos Campos, SP, Brazil
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13
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Elkins EA, Walti KA, Newberry KE, Lema SC. Identification of an oxytocinase/vasopressinase-like leucyl-cystinyl aminopeptidase (LNPEP) in teleost fish and evidence for hypothalamic mRNA expression linked to behavioral social status. Gen Comp Endocrinol 2017; 250:58-69. [PMID: 28596078 DOI: 10.1016/j.ygcen.2017.06.002] [Citation(s) in RCA: 7] [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: 03/17/2017] [Revised: 06/03/2017] [Accepted: 06/04/2017] [Indexed: 02/06/2023]
Abstract
The vasotocin/vasopressin and isotocin/mesotocin/oxytocin family of nonapeptides regulate social behaviors and physiological functions associated with reproductive physiology and osmotic balance. While experimental and correlative studies provide evidence for these nonapeptides as modulators of behavior across all classes of vertebrates, mechanisms for nonapeptide inactivation in regulating these functions have been largely overlooked. Leucyl-cystinyl aminopeptidase (LNPEP) - also known as vasopressinase, oxytocinase, placental leucine aminopeptidase (P-LAP), and insulin-regulated aminopeptidase (IRAP) - is a membrane-bound zinc-dependent metalloexopeptidase enzyme that inactivates vasopressin, oxytocin, and select other cyclic polypeptides. In humans, LNPEP plays a key role in the clearance of oxytocin during pregnancy. However, the evolutionary diversity, expression distribution, and functional roles of LNPEP remain unresolved for other vertebrates. Here, we isolated and sequenced a full-length cDNA encoding a LNPEP-like polypeptide of 1033 amino acids from the ovarian tissue of Amargosa pupfish, Cyprinodon nevadensis. This deduced polypeptide exhibited high amino acid identity to human LNPEP both in the protein's active domain that includes the peptide binding site and zinc cofactor binding motif (53.1% identity), and in an intracellular region that distinguishes LNPEP from other aminopeptidases (70.3% identity). Transcripts encoding this LNPEP enzyme (lnpep) were detected at highest relative abundance in the gonads, hypothalamus, forebrain, optic tectum, gill and skeletal muscle of adult pupfish. Further evaluation of lnpep transcript abundance in the brain of sexually-mature pupfish revealed that lnpep mRNAs were elevated in the hypothalamus of socially subordinate females and males, and at lower abundance in the telencephalon of socially dominant males compared to dominant females. These findings provide evidence of an association between behavioral social status and hypothalamic lnpep transcript abundance and suggest that variation in the rate of VT/IT peptide inactivation by LNPEP may be a contributing component in the mechanism whereby nonapeptides regulate social behavior.
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Affiliation(s)
- Emma A Elkins
- Biological Sciences Department, Center for Coastal Marine Sciences, California Polytechnic State University, San Luis Obispo, CA 93407, USA
| | - Kayla A Walti
- Biological Sciences Department, Center for Coastal Marine Sciences, California Polytechnic State University, San Luis Obispo, CA 93407, USA
| | - Kathryn E Newberry
- Biological Sciences Department, Center for Coastal Marine Sciences, California Polytechnic State University, San Luis Obispo, CA 93407, USA
| | - Sean C Lema
- Biological Sciences Department, Center for Coastal Marine Sciences, California Polytechnic State University, San Luis Obispo, CA 93407, USA.
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14
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Abstract
Oxytocin is a hypothalamic neuropeptide first recognized as a regulator of parturition and lactation which has recently gained attention for its ability to modulate social behaviors. In this chapter, we review several aspects of the oxytocinergic system, focusing on evidence for release of oxytocin and its receptor distribution in the cortex as the foundation for important networks that control social behavior. We examine the developmental timeline of the cortical oxytocin system as demonstrated by RNA, autoradiographic binding, and protein immunohistochemical studies, and describe how that might shape brain development and behavior. Many recent studies have implicated oxytocin in cognitive processes such as processing of sensory stimuli, social recognition, social memory, and fear. We review these studies and discuss the function of oxytocin in the young and adult cortex as a neuromodulator of central synaptic transmission and mediator of plasticity.
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15
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Engen K, Rosenström U, Axelsson H, Konda V, Dahllund L, Otrocka M, Sigmundsson K, Nikolaou A, Vauquelin G, Hallberg M, Jenmalm Jensen A, Lundbäck T, Larhed M. Identification of Drug-Like Inhibitors of Insulin-Regulated Aminopeptidase Through Small-Molecule Screening. Assay Drug Dev Technol 2016; 14:180-93. [PMID: 27078680 DOI: 10.1089/adt.2016.708] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Intracerebroventricular injection of angiotensin IV, a ligand of insulin-regulated aminopeptidase (IRAP), has been shown to improve cognitive functions in several animal models. Consequently, IRAP is considered a potential target for treatment of cognitive disorders. To identify nonpeptidic IRAP inhibitors, we adapted an established enzymatic assay based on membrane preparations from Chinese hamster ovary cells and a synthetic peptide-like substrate for high-throughput screening purposes. The 384-well microplate-based absorbance assay was used to screen a diverse set of 10,500 compounds for their inhibitory capacity of IRAP. The assay performance was robust with Z'-values ranging from 0.81 to 0.91, and the screen resulted in 23 compounds that displayed greater than 60% inhibition at a compound concentration of 10 μM. After hit confirmation experiments, purity analysis, and promiscuity investigations, three structurally different compounds were considered particularly interesting as starting points for the development of small-molecule-based IRAP inhibitors. After resynthesis, all three compounds confirmed low μM activity and were shown to be rapidly reversible. Additional characterization included activity in a fluorescence-based orthogonal assay and in the presence of a nonionic detergent and a reducing agent, respectively. Importantly, the characterized compounds also showed inhibition of the human ortholog, prompting our further interest in these novel IRAP inhibitors.
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Affiliation(s)
- Karin Engen
- 1 Division of Organic Pharmaceutical Chemistry, Department of Medicinal Chemistry, Uppsala University , Uppsala, Sweden
| | - Ulrika Rosenström
- 1 Division of Organic Pharmaceutical Chemistry, Department of Medicinal Chemistry, Uppsala University , Uppsala, Sweden
| | - Hanna Axelsson
- 2 Chemical Biology Consortium Sweden, Science for Life Laboratory Stockholm, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet , Solna, Sweden
| | - Vivek Konda
- 1 Division of Organic Pharmaceutical Chemistry, Department of Medicinal Chemistry, Uppsala University , Uppsala, Sweden
| | - Leif Dahllund
- 3 Drug Discovery and Development Platform, Science for Life Laboratory Stockholm , Solna, Sweden
| | - Magdalena Otrocka
- 2 Chemical Biology Consortium Sweden, Science for Life Laboratory Stockholm, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet , Solna, Sweden
| | - Kristmundur Sigmundsson
- 2 Chemical Biology Consortium Sweden, Science for Life Laboratory Stockholm, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet , Solna, Sweden
| | - Alexandros Nikolaou
- 4 Department of Molecular and Biochemical Pharmacology, Vrije Universiteit Brussel , Brussels, Belgium
| | - Georges Vauquelin
- 4 Department of Molecular and Biochemical Pharmacology, Vrije Universiteit Brussel , Brussels, Belgium
| | - Mathias Hallberg
- 5 Beijer Laboratory, Division of Biological Research on Drug Dependence, Department of Pharmaceutical Biosciences, Uppsala University , Uppsala, Sweden
| | - Annika Jenmalm Jensen
- 2 Chemical Biology Consortium Sweden, Science for Life Laboratory Stockholm, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet , Solna, Sweden
| | - Thomas Lundbäck
- 2 Chemical Biology Consortium Sweden, Science for Life Laboratory Stockholm, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet , Solna, Sweden
| | - Mats Larhed
- 6 Science for Life Laboratory Uppsala, Division of Organic Pharmaceutical Chemistry, Department of Medicinal Chemistry, Uppsala University , Uppsala, Sweden
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16
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Kobayashi H, Nomura S, Mitsui T, Ito T, Kuno N, Ohno Y, Kadomatsu K, Muramatsu T, Nagasaka T, Mizutani S. Tissue Distribution of Placental Leucine Aminopeptidase/Oxytocinase During Mouse Pregnancy. J Histochem Cytochem 2016; 52:113-21. [PMID: 14688222 DOI: 10.1177/002215540405200111] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Placental leucine aminopeptidase (P-LAP), also called oxytocinase, is an enzyme responsible for hydrolyzing oxytocin. This enzyme is identical to cystine aminopeptidase. We examined the tissue distribution of P-LAP in normal adult mice and also in mothers and fetuses during mouse pregnancy using immunohistochemical (IHC) analysis. P-LAP-immunoreactive protein was expressed in various organs in a cell- and gestational stage-dependent manner. In the kidney, P-LAP was located in distal and collecting tubules but not in proximal tubules. The islet of Langerhans in the maternal pancreas stained positively for P-LAP in the periphery in early gestation. This staining pattern changed so that both the periphery and inner cells were positive during mid-gestation and finally only inner cells were positive in late gestation. Among the hematopoietic cells in the fetal liver, only megakaryocytes showed strong expression of P-LAP. The staining intensity increased with gestation on the apical surface of trophoblasts in the placental labyrinth. These data demonstrate that P-LAP is present in a variety of tissues, and its presence is affected by pregnancy and fetal development. Therefore, P-LAP may play a significant role in various physiological processes in non-pregnant, pregnant, and fetal mice.
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Affiliation(s)
- Honami Kobayashi
- Departments of Obstetrics and Gynecology, Nagoya University Graduate School of Medicine, Nagoya, Japan
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17
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Kinjo T, Tanaka M, Osanai T, Shibutani S, Narita I, Tanno T, Nishizaki K, Ichikawa H, Kimura Y, Ishida Y, Yokota T, Shimada M, Homma Y, Tomita H, Okumura K. Enhanced p122RhoGAP/DLC-1 Expression Can Be a Cause of Coronary Spasm. PLoS One 2015; 10:e0143884. [PMID: 26624289 PMCID: PMC4666625 DOI: 10.1371/journal.pone.0143884] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 11/10/2015] [Indexed: 01/17/2023] Open
Abstract
Background We previously showed that phospholipase C (PLC)-δ1 activity was enhanced by 3-fold in patients with coronary spastic angina (CSA). We also reported that p122Rho GTPase-activating protein/deleted in liver cancer-1 (p122RhoGAP/DLC-1) protein, which was discovered as a PLC-δ1 stimulator, was upregulated in CSA patients. We tested the hypothesis that p122RhoGAP/DLC-1 overexpression causes coronary spasm. Methods and Results We generated transgenic (TG) mice with vascular smooth muscle (VSM)-specific overexpression of p122RhoGAP/DLC-1. The gene and protein expressions of p122RhoGAP/DLC-1 were markedly increased in the aorta of homozygous TG mice. Stronger staining with anti-p122RhoGAP/DLC-1 in the coronary artery was found in TG than in WT mice. PLC activities in the plasma membrane fraction and the whole cell were enhanced by 1.43 and 2.38 times, respectively, in cultured aortic vascular smooth muscle cells from homozygous TG compared with those from WT mice. Immediately after ergometrine injection, ST-segment elevation was observed in 1 of 7 WT (14%), 6 of 7 heterozygous TG (84%), and 7 of 7 homozygous TG mice (100%) (p<0.05, WT versus TGs). In the isolated Langendorff hearts, coronary perfusion pressure was increased after ergometrine in TG, but not in WT mice, despite of the similar response to prostaglandin F2α between TG and WT mice (n = 5). Focal narrowing of the coronary artery after ergometrine was documented only in TG mice. Conclusions VSM-specific overexpression of p122RhoGAP/DLC-1 enhanced coronary vasomotility after ergometrine injection in mice, which is relevant to human CSA.
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Affiliation(s)
- Takahiko Kinjo
- Department of Cardiology and Nephrology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Makoto Tanaka
- Department of Hypertension and Stroke Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Tomohiro Osanai
- Department of Health Promotion, Hirosaki University Graduate School of Health Science, Hirosaki, Japan
| | - Shuji Shibutani
- Department of Cardiology and Nephrology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Ikuyo Narita
- Department of Cardiology and Nephrology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Tomohiro Tanno
- Department of Cardiology and Nephrology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Kimitaka Nishizaki
- Department of Cardiology and Nephrology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Hiroaki Ichikawa
- Department of Cardiology and Nephrology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Yoshihiro Kimura
- Department of Cardiology and Nephrology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Yuji Ishida
- Department of Cardiology and Nephrology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Takashi Yokota
- Department of Cardiology and Nephrology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Michiko Shimada
- Department of Cardiology and Nephrology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Yoshimi Homma
- Department of Biomolecular Science, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Hirofumi Tomita
- Department of Cardiology and Nephrology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Ken Okumura
- Department of Cardiology and Nephrology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
- Department of Hypertension and Stroke Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
- * E-mail:
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18
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Svensson F, Engen K, Lundbäck T, Larhed M, Sköld C. Virtual Screening for Transition State Analogue Inhibitors of IRAP Based on Quantum Mechanically Derived Reaction Coordinates. J Chem Inf Model 2015; 55:1984-93. [DOI: 10.1021/acs.jcim.5b00359] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Fredrik Svensson
- Organic
Pharmaceutical Chemistry, Department of Medicinal Chemistry, BMC, Uppsala University, P.O.
Box 574, SE-751 23 Uppsala, Sweden
| | - Karin Engen
- Organic
Pharmaceutical Chemistry, Department of Medicinal Chemistry, BMC, Uppsala University, P.O.
Box 574, SE-751 23 Uppsala, Sweden
| | - Thomas Lundbäck
- Chemical
Biology Consortium Sweden, Science for Life Laboratory, Division of
Translational Medicine and Chemical Biology, Department of Medical
Biochemistry and Biophysics, Karolinska Institutet, Tomtebodavägen
23A, SE-171 65 Solna, Sweden
| | - Mats Larhed
- Science
for Life Laboratory, Department of Medicinal Chemistry, BMC, Uppsala University, P.O.
Box 574, SE-751 23 Uppsala, Sweden
| | - Christian Sköld
- Organic
Pharmaceutical Chemistry, Department of Medicinal Chemistry, BMC, Uppsala University, P.O.
Box 574, SE-751 23 Uppsala, Sweden
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19
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Goto Y, Ogawa K, Nakamura TJ, Hattori A, Tsujimoto M. Substrate-dependent nitric oxide synthesis by secreted endoplasmic reticulum aminopeptidase 1 in macrophages. J Biochem 2015; 157:439-49. [DOI: 10.1093/jb/mvv001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 11/28/2014] [Indexed: 01/01/2023] Open
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20
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Hermans SJ, Ascher DB, Hancock NC, Holien JK, Michell BJ, Chai SY, Morton CJ, Parker MW. Crystal structure of human insulin-regulated aminopeptidase with specificity for cyclic peptides. Protein Sci 2014; 24:190-9. [PMID: 25408552 DOI: 10.1002/pro.2604] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 11/10/2014] [Indexed: 11/12/2022]
Abstract
Insulin-regulated aminopeptidase (IRAP or oxytocinase) is a membrane-bound zinc-metallopeptidase that cleaves neuroactive peptides in the brain and produces memory enhancing effects when inhibited. We have determined the crystal structure of human IRAP revealing a closed, four domain arrangement with a large, mostly buried cavity abutting the active site. The structure reveals that the GAMEN exopeptidase loop adopts a very different conformation from other aminopeptidases, thus explaining IRAP's unique specificity for cyclic peptides such as oxytocin and vasopressin. Computational docking of a series of IRAP-specific cognitive enhancers into the crystal structure provides a molecular basis for their structure-activity relationships and demonstrates that the structure will be a powerful tool in the development of new classes of cognitive enhancers for treating a variety of memory disorders such as Alzheimer's disease.
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Affiliation(s)
- Stefan J Hermans
- ACRF Rational Drug Discovery Centre, St. Vincent's Institute of Medical Research, Fitzroy, Melbourne, Victoria, 3065, Australia
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21
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Abstract
Pseudomonas aeruginosa secretes into its environment at least seven extracellular proteases: pseudolysin (LasB protease; elastase), aeruginolysin (alkaline proteinase), staphylolysin (staphylolytic endopeptidase; LasA protease), lysyl endopeptidase (protease IV; PrpL), PASP (P. aeruginosa small protease), LepA (Large ExoProtease A), and an aminopeptidase. Their action on host proteins, both individually and synergistically, plays important roles in pathogenesis of P. aeruginosa infections. Methods to measure/detect their activities are fundamental for understanding their physiological functions, roles in pathogenesis, mechanisms of action, regulation, and secretion. Most assays for determination/detection of proteolytic activity employ modified/non-modified casein or gelatin as substrates. In the quantitative assay, fragments generated from azocasein are separated from undigested substrate by trichloroacetic acid precipitation and their absorbance is measured. In non-quantitative assays, proteolytic activity is detected as clearing zones around bacterial growth or samples of culture supernatants on casein containing solid media formed due to local casein degradation. In zymography, individual proteases are detected as clear bands in gelatin/casein containing gels after SDS-PAGE separation, renaturation and protein staining. The elastinolytic capacity of P. aeruginosa is reflected by clearing zones on nutrient agar plates containing insoluble elastin instead of casein. Mueller-Hinton agar plates on which S. aureus cells are grown as a lawn are used to assess the susceptibility of S. aureus isolates to staphylolysin. A clear zone around a staphylolysin-containing sample indicates inhibition of S. aureus growth. Methods for measuring the activity of individual proteases are based on their cleavage specificity. These include assays of elastinolytic activity of pseudolysin and/or staphylolysin using elastin-Congo red as a substrate, a method for determination of staphylolytic activity in which the rate of S. aureus cell lysis is determined spectrophotometrically, and methods for determination of peptidase activity of pseudolysin, staphylolysin, lysyl endopeptidase, and the aminopeptidase. The latter methods employ chromogenic or fluorogenic peptide derivatives comprising a short amino acid sequence matching the preferred cleavage site of the protease as substrates. As only one peptide bond is cleaved in each substrate, these assays permit kinetic studies.
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22
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Hattori A, Tsujimoto M. Endoplasmic reticulum aminopeptidases: biochemistry, physiology and pathology. J Biochem 2013; 154:219-28. [PMID: 23946506 DOI: 10.1093/jb/mvt066] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The human endoplasmic reticulum aminopeptidase (ERAP) 1 and 2 proteins were initially identified as homologues of human placental leucine aminopeptidase/insulin-regulated aminopeptidase. They are categorized as a unique class of proteases based on their subcellular localization on the luminal side of the endoplasmic reticulum. ERAPs play an important role in the N-terminal processing of the antigenic precursors that are presented on the major histocompatibility complex (MHC) class I molecules. ERAPs are also implicated in the regulation of a wide variety of physiological phenomena and pathogenic conditions. In this review, the current knowledge on ERAPs is summarized.
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Affiliation(s)
- Akira Hattori
- Division of Bioinformatics and Chemical Genomics, Department of System Chemotherapy and Molecular Sciences, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo, Kyoto 606-8501, Japan.
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23
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Mizutani S, Tsunemi T, Mizutani E, Hattori A, Tsujimoto M, Kobayashi H. New insights into the role of aminopeptidases in the treatment for both preeclampsia and preterm labor. Expert Opin Investig Drugs 2013; 22:1425-36. [PMID: 23931642 DOI: 10.1517/13543784.2013.825248] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Evidence elucidating the pathophysiology and pharmacology of conventional drugs, β-2 stimulants and magnesium sulfate, on safety and effectiveness for preeclampsia and preterm labor are rarely found. Both compounds pass through the placental barrier and could exert their adverse effects on the fetus. Exposure to these agents could be problematic long after the birth, and possibly result in diseases such as autism and cardiomyopathy. Since 1970 the possible roles of placental aminopeptidases, which degrade peptide hormones, in preeclampsia and preterm labor have been studied. AREAS COVERED Many studies reveal that the fetus secretes peptide hormones, such as angiotensin II, vasopressin, and oxytocin, under hypoxia (stress) during the course of its growth, suggesting the critical effects these hormones have during pregnancy. The roles of placental aminopeptidases, the enzymes which degrade fetal hormones without passing through the placental barrier, were clarified. A first-step production system for recombinant aminopeptidases was established, by which engineered recombinant aminopeptidases were used for further experiments testing expected efficacy on controlling the level of hormones. EXPERT OPINION The authors conclude that both aminopeptidase A and placental leucine aminopeptidase could be potentially safe and effective drugs for patients and their babies in the treatment of preeclampsia and preterm labor.
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Affiliation(s)
- Shigehiko Mizutani
- Daiya Building Ladys' Clinic , 1F, No.2, 3-15-1, Meieki, Nakamura-ku, Nagoya, 450-0002 , Japan
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Antidepressant-like effects of oxytocin in mice are dependent on the presence of insulin-regulated aminopeptidase. Int J Neuropsychopharmacol 2013. [PMID: 23177092 DOI: 10.1017/s1461145712001149] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Oxytocin is a neuromodulator with antidepressant-like effects. In vitro, oxytocin is rapidly cleaved by insulin-regulated aminopeptidase (IRAP). Oxytocin metabolites are known to exert strong central activities that are different from the effects of the parent molecule. Our goal is to investigate in vivo whether IRAP deletion modifies the antidepressant-like effects of oxytocin. Male and female C57Bl/6 mice, IRAP wild-type (IRAP(+/+)) and knock-out (IRAP(-/-)) mice were injected subcutaneously with saline, oxytocin or oxytocin combined with angiotensin IV. One hour after injection, immobility was timed during a 5 min forced swim that was preceded by an open field to study locomotor behaviour. Oxytocin induced antidepressant-like effects in male (0.25 mg/kg oxytocin) and female (0.15 mg/kg oxytocin) C57Bl/6 mice subjected to the forced swim test. Oxytocin did not influence locomotor behaviour in mice, as shown with the open field. These findings were reproduced in transgenic male (aged 3-6 months) and female (aged 12-18 months) IRAP(+/+) mice. However, the major findings of our study were that the antidepressant-like effect was reversed in angiotensin IV treated IRAP(+/+) mice and was completely absent in age- and gender-matched IRAP(-/-) mice. The lack of an antidepressant-like effect of oxytocin in young male and middle-aged female IRAP(-/-) mice attributes an important role to IRAP in mediating this effect.
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25
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Discovery of inhibitors of insulin-regulated aminopeptidase as cognitive enhancers. Int J Hypertens 2012; 2012:789671. [PMID: 23304452 PMCID: PMC3529497 DOI: 10.1155/2012/789671] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2012] [Accepted: 10/19/2012] [Indexed: 12/20/2022] Open
Abstract
The hexapeptide angiotensin IV (Ang IV) is a metabolite of angiotensin II (Ang II) and plays a central role in the brain. It was reported more than two decades ago that intracerebroventricular injection of Ang IV improved memory and learning in the rat. Several hypotheses have been put forward to explain the positive effects of Ang IV and related analogues on cognition. It has been proposed that the insulin-regulated aminopeptidase (IRAP) is the main target of Ang IV. This paper discusses progress in the discovery of inhibitors of IRAP as potential enhancers of cognitive functions. Very potent inhibitors of the protease have been synthesised, but pharmacokinetic issues (including problems associated with crossing the blood-brain barrier) remain to be solved. The paper also briefly presents an overview of the status in the discovery of inhibitors of ACE and renin, and of AT1R antagonists and AT2R agonists, in order to enable other discovery processes within the RAS system to be compared. The paper focuses on the relationship between binding affinities/inhibition capacity and the structures of the ligands that interact with the target proteins.
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Waditee-Sirisattha R, Hattori A, Shibato J, Rakwal R, Sirisattha S, Takabe T, Tsujimoto M. Role of the Arabidopsis leucine aminopeptidase 2. PLANT SIGNALING & BEHAVIOR 2011; 6:1581-3. [PMID: 21918372 PMCID: PMC3256389 DOI: 10.4161/psb.6.10.17105] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Proteolysis-related genes have diverse functions across taxa and have long been considered as key players for intracellular protein turnover. Growing evidence indicates the biological significance of peptidases in degradation, maturation and modulation of bioactive peptides/proteins. By screening T-DNA tagged lines and functional analysis approaches we unraveled the Arabidopsis leucine aminopeptidase (AtLAP2) function in amino acid turnover. Transcriptomics and metabolomics profiling data suggested involvement of AtLAP2 in specific metabolic pathways. Loss-of-function of AtLAP2 resulted in early-leaf senescent and stress-sensitive phenotypes. Our work indicates an important in planta role for AtLAP2 contributing to a further understanding of the proteases having several implications in higher plants.
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Probing the S1 specificity pocket of the aminopeptidases that generate antigenic peptides. Biochem J 2011; 435:411-20. [PMID: 21314638 DOI: 10.1042/bj20102049] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
ERAP1 (endoplasmic reticulum aminopeptidase 1), ERAP2 and IRAP (insulin-regulated aminopeptidase) are three homologous enzymes that play critical roles in the generation of antigenic peptides. These aminopeptidases excise amino acids from N-terminally extended precursors of antigenic peptides in order to generate the correct length epitopes for binding on to MHC class I molecules. The specificity of these peptidases can affect antigenic peptide selection, but has not yet been investigated in detail. In the present study we utilized a collection of 82 fluorigenic substrates to define a detailed selectivity profile for each of the three enzymes and to probe structural and functional features of the S1 (primary specificity) pocket. Molecular modelling of the three S1 pockets reveals substrate-enzyme interactions that are critical determinants for specificity. The substrate selectivity profiles suggest that IRAP largely combines the S1 specificity of ERAP1 and ERAP2, consistent with its proposed biological function. IRAP, however, does not achieve this dual specificity by simply combining structural features of ERAP1 and ERAP2, but rather by an unique amino acid change at position 541. The results of the present study provide insights on antigenic peptide selection and may prove valuable in designing selective inhibitors or activity markers for this class of enzymes.
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Peer WA. The role of multifunctional M1 metallopeptidases in cell cycle progression. ANNALS OF BOTANY 2011; 107:1171-81. [PMID: 21258033 PMCID: PMC3091800 DOI: 10.1093/aob/mcq265] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
BACKGROUND Metallopeptidases of the M1 family are found in all phyla (except viruses) and are important in the cell cycle and normal growth and development. M1s often have spatiotemporal expression patterns which allow for strict regulation of activity. Mutations in the genes encoding M1s result in disease and are often lethal. This family of zinc metallopeptidases all share the catalytic region containing a signature amino acid exopeptidase (GXMXN) and a zinc binding (HEXXH[18X]E) motif. In addition, M1 aminopeptidases often also contain additional membrane association and/or protein interaction motifs. These protein interaction domains may function independently of M1 enzymatic activity and can contribute to multifunctionality of the proteins. SCOPE A brief review of M1 metalloproteases in plants and animals and their roles in the cell cycle is presented. In animals, human puromycin-sensitive aminopeptidase (PSA) acts during mitosis and perhaps meiosis, while the insect homologue puromycin-sensitive aminopeptidase (PAM-1) is required for meiotic and mitotic exit; the remaining human M1 family members appear to play a direct or indirect role in mitosis/cell proliferation. In plants, meiotic prophase aminopeptidase 1 (MPA1) is essential for the first steps in meiosis, and aminopeptidase M1 (APM1) appears to be important in mitosis and cell division. CONCLUSIONS M1 metalloprotease activity in the cell cycle is conserved across phyla. The activities of the multifunctional M1s, processing small peptides and peptide hormones and contributing to protein trafficking and signal transduction processes, either directly or indirectly impact on the cell cycle. Identification of peptide substrates and interacting protein partners is required to understand M1 function in fertility and normal growth and development in plants.
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Affiliation(s)
- Wendy Ann Peer
- Department of Horticulture and Landscape Architecture, 625 Agriculture Mall Drive, Purdue University, West Lafayette, IN 47907 USA.
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van Endert P. Post-proteasomal and proteasome-independent generation of MHC class I ligands. Cell Mol Life Sci 2011; 68:1553-67. [PMID: 21390545 PMCID: PMC11115176 DOI: 10.1007/s00018-011-0662-1] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 02/17/2011] [Accepted: 02/18/2011] [Indexed: 12/18/2022]
Abstract
Peptide ligands presented by MHC class I molecules are produced by intracellular proteolysis, which often involves multiple steps. Initial antigen degradation seems to rely almost invariably on the proteasome, although tripeptidyl peptidase II (TPP II) and insulin-degrading enzyme (IDE) may be able to substitute for the proteasome in rare cases. Recent evidence suggests that the net effect of cytosolic aminopeptidases is destruction of potential class I ligands, although a positive role in selected cases has been documented. This may apply particularly to the trimming of long precursors by TPP II. In contrast, trimming of ligand precursors in the endoplasmic reticulum is essential for the generation of suitable peptides and has a substantial impact on the repertoire of ligands presented. Trimming by the ER aminopeptidase (ERAP) enzymes most likely acts on free precursors and is adapted to the needs of class I molecules by way of a molecular ruler mechanism. Trimming by ERAP enzymes also occurs for cross-presented ligands, which can alternatively be processed in a special endosomal compartment by insulin-regulated aminopeptidase.
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Affiliation(s)
- Peter van Endert
- Institut National de la Santé et de la Recherche Médicale, Unité 1013, Paris 75015, France.
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Goto Y, Ogawa K, Hattori A, Tsujimoto M. Secretion of endoplasmic reticulum aminopeptidase 1 is involved in the activation of macrophages induced by lipopolysaccharide and interferon-gamma. J Biol Chem 2011; 286:21906-14. [PMID: 21531727 DOI: 10.1074/jbc.m111.239111] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Endoplasmic reticulum aminopeptidase 1 (ERAP1) is a multifunctional enzyme with an important role in processing antigenic peptides presented to class I major histocompatibility complex in the endoplasmic reticulum. In this study, we found that endoplasmic reticulum-retained ERAP1 was secreted from macrophages in response to activation by treatment with lipopolysaccharide (LPS) and interferon (IFN)-γ and enhanced their phagocytic activity. Enhancement of the phagocytic activity of murine macrophage RAW264.7 cells induced by LPS/IFN-γ was inhibited by a potent aminopeptidase inhibitor, amastatin. The addition of recombinant wild-type but not inactive mutant ERAP1 to culture medium enhanced phagocytosis. These results suggest that enhancement of phagocytic activity is at least in part mediated by secreted ERAP1 through the generation of active peptides processed by the enzyme. Our data reveal ERAP1-mediated activation of macrophages for the first time and will provide new insights into the role of this enzyme in innate immunity.
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Affiliation(s)
- Yoshikuni Goto
- Laboratory of Cellular Biochemistry, RIKEN, Wako, Saitama, 351-0198, Japan
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Ascher DB, Cromer BA, Morton CJ, Volitakis I, Cherny RA, Albiston AL, Chai SY, Parker MW. Regulation of insulin-regulated membrane aminopeptidase activity by its C-terminal domain. Biochemistry 2011; 50:2611-22. [PMID: 21348480 DOI: 10.1021/bi101893w] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The development of inhibitors of insulin-regulated aminopeptidase (IRAP), a membrane-bound zinc metallopeptidase, is a promising approach for the discovery of drugs for the treatment of memory loss such as that associated with Alzheimer's disease. There is, however, no consensus in the literature about the mechanism by which inhibition occurs. Sequence alignments, secondary structure predictions, and homology models based on the structures of recently determined related metallopeptidases suggest that the extracellular region consists of four domains. Partial proteolysis and mass spectrometry reported here confirm some of the domain boundaries. We have produced purified recombinant fragments of human IRAP on the basis of these data and examined their kinetic and biochemical properties. Full-length extracellular constructs assemble as dimers with different nonoverlapping fragments dimerizing as well, suggesting an extended dimer interface. Only recombinant fragments containing domains 1 and 2 possess aminopeptidase activity and bind the radiolabeled hexapeptide inhibitor, angiotensin IV (Ang IV). However, fragments lacking domains 3 and 4 possess reduced activity, although they still bind a range of inhibitors with the same affinity as longer fragments. In the presence of Ang IV, IRAP is resistant to proteolysis, suggesting significant conformational changes occur upon binding of the inhibitor. We show that IRAP has a second Zn(2+) binding site, not associated with the catalytic region, which is lost upon binding Ang IV. Modulation of activity caused by domains 3 and 4 is consistent with a conformational change regulating access to the active site of IRAP.
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Affiliation(s)
- David B Ascher
- Centre for Structural Neurobiology and Biota Structural Biology Laboratory, St. Vincent's Institute, 9 Princes Street, Fitzroy, Victoria 3065, Australia
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Nakada TA, Russell JA, Wellman H, Boyd JH, Nakada E, Thain KR, Thair SA, Hirasawa H, Oda S, Walley KR. Leucyl/cystinyl aminopeptidase gene variants in septic shock. Chest 2011; 139:1042-1049. [PMID: 21330387 DOI: 10.1378/chest.10-2517] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Vasopressin is an essential peptide hormone regulating cardiovascular homeostasis and an adjunctive vasopressor therapy for septic shock. METHODS We tested for association between single nucleotide polymorphisms (SNPs) in vasopressin pathway genes and altered outcome in derivation (n = 589) and replication (n = 616) cohorts of patients with septic shock. The primary outcome was 28-day mortality and the secondary outcome was vasopressin clearance. In a third cardiac surgical cohort (n = 977), we tested for locus-specific heritability of serum sodium concentrations. RESULTS Of 17 tested tag SNPs in five vasopressin pathway genes (arginine vasopressin [AVP], arginine vasopressin receptor 1A and 1B [AVPR1A, AVPR1B], leucyl/cystinyl aminopeptidase [LNPEP], and oxytocin receptor [OXTR]), rs18059 in LNPEP (also known as vasopressinase) was associated with 28-day mortality in the derivation cohort (P = .037). Therefore, we resequenced the 160-kb haplotype block encompassing the LNPEP gene, including rs18059, and genotyped the 230 identified SNPs in the derivation cohort. The strongest signal was found for LNPEP rs4869317 (adjusted P = .044). The rs4869317 TT genotype was associated with increased 28-day mortality in the derivation cohort (51.0% [TT] vs 34.5% [AA/AT]; adjusted hazard ratio [HR], 1.58; 95% CI, 1.21-2.06; P = .00073) and the replication cohort (38.6% vs 29.6%; HR, 1.36; 95% CI, 1.03-1.80; P = .030). We found that the TT genotype was associated with increased plasma vasopressin clearance (P = .028), and the rs4869317 genotype accounted for 80% of the variance of serum sodium concentrations (locus-specific heritability) in cardiac surgical patients. CONCLUSIONS The genetic variation in LNPEP (vasopressinase) is associated with 28-day mortality in septic shock and is associated with biologic effects on vasopressin clearance and serum sodium regulation. Further confirmation in additional cohorts is required.
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Affiliation(s)
- Taka-Aki Nakada
- University of British Columbia, Critical Care Research Laboratories, Heart and Lung Institute, St. Paul's Hospital, Vancouver, BC, Canada
| | - James A Russell
- University of British Columbia, Critical Care Research Laboratories, Heart and Lung Institute, St. Paul's Hospital, Vancouver, BC, Canada
| | | | - John H Boyd
- University of British Columbia, Critical Care Research Laboratories, Heart and Lung Institute, St. Paul's Hospital, Vancouver, BC, Canada
| | - Emiri Nakada
- University of British Columbia, Critical Care Research Laboratories, Heart and Lung Institute, St. Paul's Hospital, Vancouver, BC, Canada
| | - Katherine R Thain
- University of British Columbia, Critical Care Research Laboratories, Heart and Lung Institute, St. Paul's Hospital, Vancouver, BC, Canada
| | - Simone A Thair
- University of British Columbia, Critical Care Research Laboratories, Heart and Lung Institute, St. Paul's Hospital, Vancouver, BC, Canada
| | - Hiroyuki Hirasawa
- Department of Emergency and Critical Care Medicine, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Shigeto Oda
- Department of Emergency and Critical Care Medicine, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Keith R Walley
- University of British Columbia, Critical Care Research Laboratories, Heart and Lung Institute, St. Paul's Hospital, Vancouver, BC, Canada.
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Georgiadou D, Hearn A, Evnouchidou I, Chroni A, Leondiadis L, York IA, Rock KL, Stratikos E. Placental leucine aminopeptidase efficiently generates mature antigenic peptides in vitro but in patterns distinct from endoplasmic reticulum aminopeptidase 1. THE JOURNAL OF IMMUNOLOGY 2010; 185:1584-92. [PMID: 20592285 DOI: 10.4049/jimmunol.0902502] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
All three members of the oxytocinase subfamily of M1 aminopeptidases, endoplasmic reticulum aminopeptidase 1 (ERAP1), ERAP2, and placental leucine aminopeptidase (PLAP), also known as insulin-regulated aminopeptidase, have been implicated in the generation of MHC class I-presented peptides. ERAP1 and 2 trim peptides in the endoplasmic reticulum for direct presentation, whereas PLAP has been recently implicated in cross-presentation. The best characterized member of the family, ERAP1, has unique enzymatic properties that fit well with its role in Ag processing. ERAP1 can trim a large variety of long peptide sequences and efficiently accumulate mature antigenic epitopes of 8-9 aa long. In this study, we evaluate the ability of PLAP to process antigenic peptide precursors in vitro and compare it with ERAP1. We find that, similar to ERAP1, PLAP can trim a variety of long peptide sequences efficiently and, in most cases, accumulates appreciable amounts of correct length mature antigenic epitope. Again, similar to ERAP1, PLAP continued trimming some of the epitopes tested and accumulated smaller products effectively destroying the epitope. However, the intermediate accumulation properties of ERAP1 and PLAP are distinct and epitope dependent, suggesting that these two enzymes may impose different selective pressures on epitope generation. Overall, although PLAP has the necessary enzymatic properties to participate in generating or destroying MHC class I-presented peptides, its trimming behavior is distinct from that of ERAP1, something that supports a separate role for these two enzymes in Ag processing.
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Affiliation(s)
- Dimitra Georgiadou
- Protein Chemistry Laboratory, Institute of Radioisotopes and Radiodiagnostic Products, National Centre for Scientific Research "Demokritos," Athens 15310, Greece
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Beyer CE, Dwyer JM, Platt BJ, Neal S, Luo B, Ling HP, Lin Q, Mark RJ, Rosenzweig-Lipson S, Schechter LE. Angiotensin IV elevates oxytocin levels in the rat amygdala and produces anxiolytic-like activity through subsequent oxytocin receptor activation. Psychopharmacology (Berl) 2010; 209:303-11. [PMID: 20224888 DOI: 10.1007/s00213-010-1791-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Accepted: 01/29/2010] [Indexed: 10/19/2022]
Abstract
INTRODUCTION The effects of angiotensin (Ang) IV result from binding to a constitutively active metallopeptidase known as the AT(4) receptor (or oxytocinase/insulin-regulated membrane aminopeptidase). While in vitro evidence indicates that Ang IV inhibits the peptidase activity of AT(4) receptors, leading to increases in the concentrations of several peptides, including oxytocin, the consequence of inhibiting AT(4) peptidase activity in vivo remains unresolved. DISCUSSION Microdialysis coupled to immunoassay techniques revealed that systemic and intra-amygdala injection of Nle-Ang IV, a metabolically stable derivative of Ang IV, significantly elevated extracellular levels of oxytocin in the rat amygdala. Based on earlier reports describing the anxiolytic-like effects of oxytocin, we investigated whether disrupting AT(4) peptidase activity would yield similar responses. In the mouse four-plate test, acute treatment with either Nle-Ang IV or LVV-hemorphin-7, a related AT(4) receptor ligand, elicited significant increases in the number of punished crossings. These behavioral responses were comparable to the anxiolytic-like effects of oxytocin and to the standard anxiolytic agent, chlordiazepoxide. Cotreatment with either the AT(4) receptor antagonist, divalinal, or the selective oxytocin receptor antagonist, WAY-162720, reversed the anxiolytic-like effects of Nle-Ang IV, while combining ineffective doses of Nle-Ang IV and oxytocin increased the number of punished crossings in this assay. Conversely, Nle-Ang IV and LVV-hemorphin-7 were inactive in the mouse tail suspension test of antidepressant activity. These findings represent the first in vivo demonstration of the peptidase activity of AT(4) receptors, confirm the anxiolytic-like properties of Ang IV, and reveal a unique and previously uncharacterized relationship between AT(4) and oxytocin receptor systems.
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Affiliation(s)
- Chad E Beyer
- Pfizer Global Research and Development CN8000, Princeton, NJ, 08543-8000, USA.
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Maruyama M, Arisaka N, Goto Y, Ohsawa Y, Inoue H, Fujiwara H, Hattori A, Tsujimoto M. Histidine 379 of human laeverin/aminopeptidase Q, a nonconserved residue within the exopeptidase motif, defines its distinctive enzymatic properties. J Biol Chem 2009; 284:34692-702. [PMID: 19819873 DOI: 10.1074/jbc.m109.066712] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human laeverin/aminopeptidase Q (LVRN/APQ) is a novel member of the M1 family of zinc aminopeptidases and is specifically expressed on the cell surface of human extravillous trophoblasts. Multiple sequence alignment of human M1 aminopeptidase revealed that the first Gly residue within the conserved exopeptidase motif of the M1 family, GXMEN motif, is uniquely substituted for His in human LVRN/APQ. In this study, we evaluated the roles of nonconserved His(379), comprising the exopeptidase motif in the enzymatic properties of human LVRN/APQ. We revealed that the substitution of His(379) with Gly caused significant changes in substrate specificity both toward fluorogenic substrates and natural peptide hormones. In addition, the susceptibilities of bestatin, a sensitive inhibitor for human LVRN/APQ, and natural inhibitory peptides were decreased in the H379G mutant. A molecular model suggested a conformational difference between wild-type and H379G human LVRN/APQs. These results indicate that His(379) of the enzyme plays essential roles in its distinctive enzymatic properties and contributes to maintaining the appropriate structure of the catalytic cavity of the enzyme. Our data may bring new insight into the biological significance of the unique exopeptidase motif of LVRN/APQ obtained during the evolution of primates.
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Affiliation(s)
- Masato Maruyama
- Laboratory of Cellular Biochemistry, RIKEN, Wako, Saitama 351-0198
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Oxytocin hypersensitivity in pregnant P-LAP deficient mice. Life Sci 2009; 84:668-72. [DOI: 10.1016/j.lfs.2009.02.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2008] [Revised: 01/19/2009] [Accepted: 02/09/2009] [Indexed: 12/20/2022]
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De Bundel D, Smolders I, Vanderheyden P, Michotte Y. Ang II and Ang IV: unraveling the mechanism of action on synaptic plasticity, memory, and epilepsy. CNS Neurosci Ther 2009; 14:315-39. [PMID: 19040556 DOI: 10.1111/j.1755-5949.2008.00057.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The central angiotensin system plays a crucial role in cardiovascular regulation. More recently, angiotensin peptides have been implicated in stress, anxiety, depression, cognition, and epilepsy. Angiotensin II (Ang II) exerts its actions through AT(1) and AT(2) receptors, while most actions of its metabolite Ang IV were believed to be independent of AT(1) or AT(2) receptor activation. A specific binding site with high affinity for Ang IV was discovered and denominated "AT(4) receptor". The beneficiary effects of AT(4) ligands in animal models for cognitive impairment and epileptic seizures initiated the search for their mechanism of action. This proved to be a challenging task, and after 20 years of research, the nature of the "AT(4) receptor" remains controversial. Insulin-regulated aminopeptidase (IRAP) was first identified as the high-affinity binding site for AT(4) ligands. Recently, the hepatocyte growth factor receptor c-MET was also proposed as a receptor for AT(4) ligands. The present review focuses on the effects of Ang II and Ang IV on synaptic transmission and plasticity, learning, memory, and epileptic seizure activity. Possible interactions of Ang IV with the classical AT(1) and AT(2) receptor subtypes are evaluated, and other potential mechanisms by which AT(4) ligands may exert their effects are discussed. Identification of these mechanisms may provide a valuable target in the development in novel drugs for the treatment of cognitive disorders and epilepsy.
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Affiliation(s)
- Dimitri De Bundel
- Research Group Experimental Pharmacology, Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Vrije Universiteit Brussel, Brussels, Belgium
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Upregulation of soluble vascular endothelial growth factor receptor type 1 by endogenous prostacyclin inhibitor coupling factor 6 in vascular endothelial cells: a role of acidosis-induced c-Src activation. Hypertens Res 2009; 32:182-7. [PMID: 19262480 DOI: 10.1038/hr.2008.24] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Vascular endothelial growth factor (VEGF) is a well-known promoter of angiogenesis, but its receptor VEGFR-1 and a soluble short form of VEGFR-1 (sFlt-1) play a negative role in the VEGF signal pathway by trapping VEGF. We recently showed that endogenous prostacyclin inhibitor coupling factor 6 (CF6) forces the clockwise rotation of F(1) motor of plasma membrane adenosine triphosphate synthase and induces intracellular acidosis and c-Src activation. We investigated the role of CF6 in regulation of sFlt-1, and its mechanism in human umbilical vein endothelial cells. The ratio of sFlt-1 to glyceraldehyde 3-phosphate dehydrogenase mRNA was increased at 24 h by 1.59+/-0.29-fold by 10(-7) M CF6 (P<0.05), concomitantly with the increases in intercellular adhesion molecule-1 and lectin-like oxidized low-density lipoprotein receptor-1 and no change in VEGF-A. When the dose of CF6 was increased to 10(-6) M, no further increase in sFlt-1 mRNA was observed. The release of sFlt-1 protein was increased by 1.72+/-0.24-fold (P<0.05) at 48 h after exposure to CF6 at 10(-7) M, and it was blocked by pretreatment with anti-CF6 antibody. The immunoreactive bands for sFlt-1 and VEGFR-1 were both increased by CF6 to similar degrees. Pretreatment with PP1, an inhibitor of c-Src, and 10(-5) Mefrapeptin, an inhibitor of F(1) motor, inhibited CF6-induced increases in expression and release of sFlt-1 (P<0.05). In mice overexpressing CF6, the plasma level of sFlt-1 was increased by 1.36+/-0.29-fold compared with that in wild-type mice (P<0.05). These indicate that CF6 might increase the expression and release of sFlt-1 in the vessels through acidosis-induced c-Src activation.
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Osanai T, Tomita H, Kushibiki M, Yamada M, Tanaka M, Ashitate T, Echizen T, Katoh C, Magota K, Okumura K. Coupling factor 6 enhances Src-mediated responsiveness to angiotensin II in resistance arterioles and cells. Cardiovasc Res 2008; 81:780-7. [PMID: 19106112 DOI: 10.1093/cvr/cvn356] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
AIMS Coupling factor 6 (CF6) induces hypertension by attenuating the endothelial generation of prostacyclin. However, intracellular signalling of CF6 in the resistance arteriole vascular smooth muscle cells (VSMCs) that are directly related to vasoconstriction has not been determined. Here we investigated the direct effect of exogenous CF6 on Ca2+ signalling in cultured VSMCs and the in vivo role of endogenous CF6 in the genesis of hypertension using CF6 transgenic (TG) mice. METHODS AND RESULTS CF6 induced a monophasic increase in the intracellular free Ca2+ concentration ([Ca2+]i) through nifedipine-sensitive Ca2+ channels in A7r5 cells, a cell line of VSMCs, and enhanced the angiotensin II-induced spike phase of [Ca2+]i to a greater degree in VSMCs derived from spontaneously hypertensive rats (SHRs). In the mesenteric arterioles obtained from CF6-TG mice that manifested hypertension, angiotensin II-induced vasoconstriction was enhanced, compared with wild-type mice, and its enhancement was abolished by an anti-CF6 antibody. Pre-treatment with PP1, a tyrosine kinase c-Src inhibitor, blocked CF6-induced increase in Ca2+ signalling in VSMCs and vasoconstriction in TG mice. The receptor of CF6 was F1 motor of adenosine triphosphate (ATP) synthase with a higher affinity in SHRs. CF6 decreased intracellular pH via activation of ATPase activity and led to c-Src activation to a greater degree in SHR-derived VSMCs. CONCLUSION CF6 causes hypertension by directly enhancing Ca2+ signalling in VSMCs and vasoconstriction in the mesenteric arteriolar network via c-Src activation.
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Affiliation(s)
- Tomohiro Osanai
- Department of Cardiology, Hirosaki University Graduate School of Medicine, 5 Zaifu-Cho, Hirosaki 036-8562, Japan.
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Glutamine-181 is crucial in the enzymatic activity and substrate specificity of human endoplasmic-reticulum aminopeptidase-1. Biochem J 2008; 416:109-16. [PMID: 18593381 DOI: 10.1042/bj20080965] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
ERAP-1 (endoplasmic-reticulum aminopeptidase-1) is a multifunctional enzyme with roles in the regulation of blood pressure, angiogenesis and the presentation of antigens to MHC class I molecules. Whereas the enzyme shows restricted specificity toward synthetic substrates, its substrate specificity toward natural peptides is rather broad. Because of the pathophysiological significance of ERAP-1, it is important to elucidate the molecular basis of its enzymatic action. In the present study we used site-directed mutagenesis to identify residues affecting the substrate specificity of human ERAP-1 and identified Gln(181) as important for enzymatic activity and substrate specificity. Replacement of Gln(181) by aspartic acid resulted in a significant change in substrate specificity, with Q181D ERAP-1 showing a preference for basic amino acids. In addition, Q181D ERAP-1 cleaved natural peptides possessing a basic amino acid at the N-terminal end more efficiently than did the wild-type enzyme, whereas its cleavage of peptides with a non-basic amino acid was significantly reduced. Another mutant enzyme, Q181E, also revealed some preference for peptides with a basic N-terminal amino acid, although it had little hydrolytic activity toward the synthetic peptides tested. Other mutant enzymes, including Q181N and Q181A ERAP-1s, revealed little enzymatic activity toward synthetic or peptide substrates. These results indicate that Gln(181) is critical for the enzymatic activity and substrate specificity of ERAP-1.
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41
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Evnouchidou I, Momburg F, Papakyriakou A, Chroni A, Leondiadis L, Chang SC, Goldberg AL, Stratikos E. The internal sequence of the peptide-substrate determines its N-terminus trimming by ERAP1. PLoS One 2008; 3:e3658. [PMID: 18987748 PMCID: PMC2573961 DOI: 10.1371/journal.pone.0003658] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2008] [Accepted: 10/20/2008] [Indexed: 11/26/2022] Open
Abstract
Background Endoplasmic reticulum aminopeptidase 1 (ERAP1) trims N-terminally extended antigenic peptide precursors down to mature antigenic peptides for presentation by major histocompatibility complex (MHC) class I molecules. ERAP1 has unique properties for an aminopeptidase being able to trim peptides in vitro based on their length and the nature of their C-termini. Methodology/Principal Findings In an effort to better understand the molecular mechanism that ERAP1 uses to trim peptides, we systematically analyzed the enzyme's substrate preferences using collections of peptide substrates. We discovered strong internal sequence preferences of peptide N-terminus trimming by ERAP1. Preferences were only found for positively charged or hydrophobic residues resulting to trimming rate changes by up to 100 fold for single residue substitutions and more than 40,000 fold for multiple residue substitutions for peptides with identical N-termini. Molecular modelling of ERAP1 revealed a large internal cavity that carries a strong negative electrostatic potential and is large enough to accommodate peptides adjacent to the enzyme's active site. This model can readily account for the strong preference for positively charged side chains. Conclusions/Significance To our knowledge no other aminopeptidase has been described to have such strong preferences for internal residues so distal to the N-terminus. Overall, our findings indicate that the internal sequence of the peptide can affect its trimming by ERAP1 as much as the peptide's length and C-terminus. We therefore propose that ERAP1 recognizes the full length of its peptide-substrate and not just the N- and C- termini. It is possible that ERAP1 trimming preferences influence the rate of generation and the composition of antigenic peptides in vivo.
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Affiliation(s)
- Irini Evnouchidou
- National Centre for Scientific Research “Demokritos”, IRRP, Aghia Paraskevi, Greece
| | - Frank Momburg
- Department of Molecular Immunology, German Cancer Research Centre, (DKFZ), Heidelberg, Germany
| | - Athanasios Papakyriakou
- Institute of Physical Chemistry, National Centre for Scientific Research “Demokritos”, Aghia Paraskevi, Greece
| | - Angeliki Chroni
- National Centre for Scientific Research “Demokritos”, Institute of Biology, Aghia Paraskevi, Greece
| | - Leondios Leondiadis
- National Centre for Scientific Research “Demokritos”, IRRP, Aghia Paraskevi, Greece
| | - Shih-Chung Chang
- Institute of Microbiology and Biochemistry, Department of Biochemical Science and Technology, National Taiwan University, Taipei, Taiwan, Republic of China
| | - Alfred L. Goldberg
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Efstratios Stratikos
- National Centre for Scientific Research “Demokritos”, IRRP, Aghia Paraskevi, Greece
- * E-mail:
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42
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Kawai M, Araragi K, Shimizu Y, Hara Y. Identification of placental leucine aminopeptidase and triton-slowed aminopeptidase N in serum of pregnant women. Clin Chim Acta 2008; 400:37-41. [PMID: 18996364 DOI: 10.1016/j.cca.2008.10.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2008] [Revised: 10/02/2008] [Accepted: 10/03/2008] [Indexed: 11/24/2022]
Abstract
BACKGROUND Previously, we found characteristic triton-slowed bands of aminopeptidase N (APN) in cholestatic serum by triton-polyacrylamide gel electrophoresis (triton-PAGE) [Makoto Kawai, Yukichi Hara, Triton-polyacrylamide gel electrophoresis and leucine aminopeptidase activity staining detect Triton-slowed bands including high-molecular-mass aminopeptidase N (CD13) isoform in cholestatic patient sera. Clin Chim Acta 2006; 364:188-195]. METHODS Sera from 14 normal pregnant women were electrophoresed on polyacrylamide gel containing 0.02 l/l triton (triton-PAGE) or a 0-0.02 l/l horizontal gradient of triton (gradient-triton-PAGE), and stained with leucine-beta-naphthylamide. Some samples were pretreated with a monoclonal APN antibody or rabbit anti-placental leucine aminopeptidase (PLAP) serum. The stained bands were eluted from the gel, treated with N- and O-glycosidase, and analyzed by Western blotting with rabbit anti-APN or anti-PLAP serum. RESULTS Triton-PAGE clearly differentiated 5 LAP activity bands (1-5 from the front). Gradient-triton-PAGE revealed that bands 4-5 were slowed by triton (triton-slowed bands) much more than bands 1-3. Triton-PAGE of antibody-treated serum showed that bands 1, 2, 4, and 5 are mainly APN and that band 3 is PLAP. The molecular mass of PLAP was about 130-140 kDa before treatment with glycosidases but 100 kDa after. Triton-PAGE detected PLAP in 13 and triton-slowed APN in 4 of the 14 women. CONCLUSIONS Triton-PAGE differentiates PLAP from APN. Triton-slowed APN as well as PLAP is present in the serum of pregnant women.
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Affiliation(s)
- Makoto Kawai
- Department of Gastroenterology, Tokyo Kyosai Hospital, Tokyo, Japan.
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43
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Axton R, Wallis JA, Taylor H, Hanks M, Forrester LM. Aminopeptidase O contains a functional nucleolar localization signal and is implicated in vascular biology. J Cell Biochem 2008; 103:1171-82. [PMID: 17803194 DOI: 10.1002/jcb.21497] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We have identified a gene trap integration into Aminopeptidase O, the gene encoding a member of the M1 family of metalloproteases. Using the betagal reporter of the gene trap vector, we have revealed that at least some ApO isoforms are expressed predominantly in embryonic and adult blood vessels leading us to propose that ApO plays a role in vascular cell biology. The protein produced from an engineered Gfp-ApO fusion cDNA localises to the nucleolus in transfected COS7 cells. We confirm that indeed the APO protein contains a functional nucleolar localisation domain by demonstrating that GFP-APO fusion proteins that lack the predicted nucleolar localisation signal are retained in the cytoplasm. We report the existence of multiple alternatively spliced Apo isoforms that differ with respect to the presence of exons encoding important functional domains. Alternative splicing predictably produces protein products with or without the catalytic domain and/or a nucleolar localisation signal and therefore likely represents an important mechanism in regulating the biological activity of APO that has been reported to cleave one of the peptides of the renin angiotensin pathway.
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Affiliation(s)
- Richard Axton
- Queen's Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
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44
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Tsujimoto M, Goto Y, Maruyama M, Hattori A. Biochemical and enzymatic properties of the M1 family of aminopeptidases involved in the regulation of blood pressure. Heart Fail Rev 2007; 13:285-91. [DOI: 10.1007/s10741-007-9064-8] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2007] [Accepted: 10/16/2007] [Indexed: 10/22/2022]
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45
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Involvement of insulin-regulated aminopeptidase in the effects of the renin–angiotensin fragment angiotensin IV: a review. Heart Fail Rev 2007; 13:321-37. [DOI: 10.1007/s10741-007-9062-x] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Accepted: 10/16/2007] [Indexed: 10/22/2022]
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46
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Wallis MG, Lankford MF, Keller SR. Vasopressin is a physiological substrate for the insulin-regulated aminopeptidase IRAP. Am J Physiol Endocrinol Metab 2007; 293:E1092-102. [PMID: 17684103 DOI: 10.1152/ajpendo.00440.2007] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Insulin-regulated aminopeptidase (IRAP) is a membrane aminopeptidase and is homologous to the placental leucine aminopeptidase, P-LAP. IRAP has a wide distribution but has been best characterized in adipocytes and myocytes. In these cells, IRAP colocalizes with the glucose transporter GLUT4 to intracellular vesicles and, like GLUT4, translocates from these vesicles to the cell surface in response to insulin. Earlier studies demonstrated that purified IRAP cleaves several peptide hormones and that, concomitant with the appearance of IRAP at the surface of insulin-stimulated adipocytes, aminopeptidase activity toward extracellular substrates increases. In the present study, to identify in vivo substrates for IRAP, we tested potential substrates for cleavage by IRAP-deficient (IRAP(-/-)) and control mice. We found that vasopressin and oxytocin were not processed from the NH(2) terminus by isolated IRAP(-/-) adipocytes and skeletal muscles. Vasopressin was not cleaved from the NH(2) terminus after injection into IRAP(-/-) mice and exhibited a threefold increased half-life in the circulation of IRAP(-/-) mice. Consistent with this finding, endogenous plasma vasopressin levels were elevated twofold in IRAP(-/-) mice, and vasopressin levels in IRAP(-/-) brains, where plasma vasopressin originates, showed a compensatory decrease. We further established that insulin increased the clearance of vasopressin from control but not from IRAP(-/-) mice. In conclusion, we have identified vasopressin as the first physiological substrate for IRAP. Changes in plasma and brain vasopressin levels in IRAP(-/-) mice suggest a significant role for IRAP in regulating vasopressin. We have also uncovered a novel IRAP-dependent insulin effect: to acutely modify vasopressin.
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Affiliation(s)
- Michelle G Wallis
- Division of Endocrinology, Department of Medicine, University of Virginia, Charlottesville, Virginia 22908, USA
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47
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Albiston AL, Peck GR, Yeatman HR, Fernando R, Ye S, Chai SY. Therapeutic targeting of insulin-regulated aminopeptidase: heads and tails? Pharmacol Ther 2007; 116:417-27. [PMID: 17900701 DOI: 10.1016/j.pharmthera.2007.07.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2007] [Accepted: 07/30/2007] [Indexed: 10/22/2022]
Abstract
Insulin-regulated aminopeptidase, IRAP, is an abundant protein that was initially cloned from a rat epididymal fat pad cDNA library as a marker protein for specialized vesicles containing the insulin-responsive glucose transporter GLUT4, wherein it is thought to participate in the tethering and trafficking of GLUT4 vesicles. The same protein was independently cloned from human placental cDNA library as oxytocinase and is proposed to have a primary role in the regulation of circulating oxytocin (OXY) during the later stages of pregnancy. More recently, IRAP was identified as the specific binding site for angiotensin IV, and we propose that it mediates the memory-enhancing effects of the peptide. This protein appears to have multiple physiological roles that are tissue- and domain-specific; thus the protein can be specifically targeted for treating different clinical conditions.
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Affiliation(s)
- Anthony L Albiston
- Howard Florey Institute of Experimental Physiology and Medicine, University of Melbourne, Parkville, Victoria 3010, Australia
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48
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Maruyama M, Hattori A, Goto Y, Ueda M, Maeda M, Fujiwara H, Tsujimoto M. Laeverin/Aminopeptidase Q, a Novel Bestatin-sensitive Leucine Aminopeptidase Belonging to the M1 Family of Aminopeptidases. J Biol Chem 2007; 282:20088-96. [PMID: 17525158 DOI: 10.1074/jbc.m702650200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Laeverin/aminopeptidase Q (APQ) is a cell surface protein specifically expressed on human embryo-derived extravillous trophoblasts that invades the uterus during placentation. The cDNA cloning of Laeverin/APQ revealed that the sequence encodes a protein with 990 amino acid residues, and Laeverin/APQ contains the HEXXHX(18)E gluzincin motif, which is characteristic of the M1 family of aminopeptidases, although the exopeptidase motif of the family, GAMEN, is uniquely substituted for the HAMEN sequence. In this study, we expressed a recombinant human Laeverin/APQ using a baculovirus expression system, purified to homogeneity, and characterized its enzymatic properties. It was found that Laeverin/APQ had a broad substrate specificity toward synthetic substrate, although it showed a preference for Leu-4-methylcoumaryl-7-amide. Searching natural substrates, we found that Laeverin/APQ was able to cleave the N-terminal amino acid of several peptides such as angiotensin III, kisspeptin-10, and endokinin C, which are abundantly expressed in the placenta. In contrast to the case with other M1 aminopeptidases, bestatin inhibited the aminopeptidase activity of Laeverin/APQ much more effectively than other known aminopeptidase inhibitors. These results indicate that Laeverin/APQ is a novel bestatin-sensitive leucine aminopeptidase and suggest that the enzyme plays important roles in human placentation by regulating biological activity of key peptides at the embryo-maternal interface.
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Affiliation(s)
- Masato Maruyama
- Laboratory of Cellular Biochemistry, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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Johnson MP, Fitzpatrick E, Dyer TD, Jowett JBM, Brennecke SP, Blangero J, Moses EK. Identification of two novel quantitative trait loci for pre-eclampsia susceptibility on chromosomes 5q and 13q using a variance components-based linkage approach. ACTA ACUST UNITED AC 2006; 13:61-7. [PMID: 17085769 DOI: 10.1093/molehr/gal095] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Pre-eclampsia/eclampsia (PE/E) is a common and serious disorder of human pregnancy that is associated with substantial maternal and perinatal morbidity and mortality. The suspected aetiology of PE/E is complex, with susceptibility being attributable to multiple environmental factors and a large genetic component. By assuming that the underlying liability towards PE/E susceptibility is inherently quantitative, any PE/E susceptibility gene would represent a quantitative trait locus (QTL). This assumption enables a more refined and powerful variance components procedure using a threshold model for our PE/E statistical analysis. Using this more efficient linkage approach, we have now re-analysed our previously completed Australian/New Zealand genome scan data to identify two novel PE/E susceptibility QTLs on chromosomes 5q and 13q. We have obtained strong evidence of linkage on 5q with a peak logarithm-of-odds (LOD) score of 3.12 between D5S644 and D5S433 [at approximately 121 centimorgan (cM)] and strong evidence of linkage on 13q with a peak LOD score of 3.10 between D13S1265 and D13S173 (at approximately 123 cM). Objective identification and prioritization of positional candidate genes using the quantitative bioinformatics program GeneSniffer revealed highly plausible PE/E candidate genes encoding aminopeptidase enzymes and a placental peptide hormone on the 5q QTL and two type IV collagens on the 13q QTL regions, respectively.
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Affiliation(s)
- M P Johnson
- Department of Genetics, Southwest Foundation for Biomedical Research, San Antonio, TX 78245-0549, USA.
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50
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Goto Y, Hattori A, Ishii Y, Mizutani S, Tsujimoto M. Enzymatic Properties of Human Aminopeptidase A. J Biol Chem 2006; 281:23503-13. [PMID: 16790432 DOI: 10.1074/jbc.m603191200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Aminopeptidase A (APA) is a type II membrane-bound protein implicated in the regulation of blood pressure in the brain renin-angiotensin system. In this study, a recombinant soluble form of APA was expressed in a baculovirus system, purified to homogeneity, and characterized. By using synthetic substrates, it was shown that although the enzyme has a rather broad substrate specificity in the absence of Ca2+, the preferential release of acidic amino acid residues was observed in the presence of Ca2+. Moreover, Ca2+ up- or down-regulated the enzymatic activity depending on the substrate. By searching for natural substrates of APA, we found that peptides having acidic amino acids at their N terminus (angiotensin II, neurokinin B, cholecystokinin-8, and chromogranin A) were cleaved by the enzyme efficiently in the presence but not in the absence of Ca2+. Moreover kallidin (Lys-bradykinin) was converted to bradykinin effectively only in the absence of Ca2+. These results suggest that Ca2+ increases the preference of the enzyme for the peptide substrates having N-terminal acidic amino acids. In addition, we found that angiotensin IV could bind to APA both in the presence and absence of Ca2+ and inhibited the enzymatic activity of APA competitively, suggesting that angiotensin IV acts as a negative regulator of the enzyme once generated from angiotensin II by the serial actions of aminopeptidases. Taken together, these results suggest that there exists a complex regulation of the enzymatic activity of APA, which may contribute to homeostasis such as regulation of blood pressure, maintenance of memory, and normal pregnancy by controlling the concentrations of peptide substrates.
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Affiliation(s)
- Yoshikuni Goto
- Laboratory of Cellular Biochemistry, RIKEN, Wako, Saitama, 351-0198, Japan
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