1
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Silva-Reis SC, Correia XC, Costa-Almeida HF, Pires-Lima BL, Maronde D, Costa VM, García-Mera X, Cruz L, Brea J, Loza MI, Rodríguez-Borges JE, Sampaio-Dias IE. Stapling Amantadine to Melanostatin Neuropeptide: Discovery of Potent Positive Allosteric Modulators of the D 2 Receptors. ACS Med Chem Lett 2023; 14:1656-1663. [PMID: 38116429 PMCID: PMC10726482 DOI: 10.1021/acsmedchemlett.3c00264] [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: 06/16/2023] [Revised: 10/28/2023] [Accepted: 11/08/2023] [Indexed: 12/21/2023] Open
Abstract
This work describes the synthesis and pharmacological and toxicological evaluation of melanostatin (MIF-1) bioconjugates with amantadine (Am) via a peptide linkage. The data from the functional assays at human dopamine D2 receptors (hD2R) showed that bioconjugates 1 (EC50 = 26.39 ± 3.37 nM) and 2 (EC50 = 17.82 ± 4.24 nM) promote a 3.3- and 4.9-fold increase of dopamine potency, respectively, at 0.01 nM, with no effect on the efficacy (Emax = 100%). In this assay, MIF-1 was only active at the highest concentration tested (EC50 = 23.64 ± 6.73 nM, at 1 nM). Cytotoxicity assays in differentiated SH-SY5Y cells showed that both MIF-1 (94.09 ± 5.75%, p < 0.05) and carbamate derivative 2 (89.73 ± 4.95%, p < 0.0001) exhibited mild but statistical significant toxicity (assessed through the MTT reduction assay) at 200 μM, while conjugate 1 was found nontoxic at this concentration.
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Affiliation(s)
- Sara C. Silva-Reis
- LAQV/REQUIMTE,
Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, 4169-007 Porto, Portugal
- UCIBIO/REQUIMTE,
Laboratory of Toxicology, Department of Biological Sciences, Faculty
of Pharmacy, University of Porto, 4050-313 Porto, Portugal
| | - Xavier C. Correia
- LAQV/REQUIMTE,
Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, 4169-007 Porto, Portugal
- UCIBIO/REQUIMTE,
Laboratory of Toxicology, Department of Biological Sciences, Faculty
of Pharmacy, University of Porto, 4050-313 Porto, Portugal
| | - Hugo F. Costa-Almeida
- LAQV/REQUIMTE,
Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, 4169-007 Porto, Portugal
- UCIBIO/REQUIMTE,
Laboratory of Toxicology, Department of Biological Sciences, Faculty
of Pharmacy, University of Porto, 4050-313 Porto, Portugal
| | - Beatriz L. Pires-Lima
- LAQV/REQUIMTE,
Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, 4169-007 Porto, Portugal
| | - Daiane Maronde
- LAQV/REQUIMTE,
Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, 4169-007 Porto, Portugal
| | - Vera M. Costa
- UCIBIO/REQUIMTE,
Laboratory of Toxicology, Department of Biological Sciences, Faculty
of Pharmacy, University of Porto, 4050-313 Porto, Portugal
- Associate
Laboratory i4HB - Institute for Health and Bioeconomy, Laboratory
of Toxicology, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal
| | - Xerardo García-Mera
- Department
of Organic Chemistry, Faculty of Pharmacy, University of Santiago de Compostela, E-15782 Santiago de Compostela, Spain
| | - Luís Cruz
- LAQV/REQUIMTE,
Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, 4169-007 Porto, Portugal
| | - José Brea
- Innopharma
Screening Platform, Biofarma Research group, Centre of Research in
Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de Compostela, E-15782 Santiago de Compostela, Spain
| | - María Isabel Loza
- Innopharma
Screening Platform, Biofarma Research group, Centre of Research in
Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de Compostela, E-15782 Santiago de Compostela, Spain
| | - José E. Rodríguez-Borges
- LAQV/REQUIMTE,
Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, 4169-007 Porto, Portugal
| | - Ivo E. Sampaio-Dias
- LAQV/REQUIMTE,
Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, 4169-007 Porto, Portugal
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2
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A Novel Cosegregating DCTN1 Splice Site Variant in a Family with Bipolar Disorder May Hold the Key to Understanding the Etiology. Genes (Basel) 2020; 11:genes11040446. [PMID: 32325768 PMCID: PMC7231292 DOI: 10.3390/genes11040446] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 04/08/2020] [Accepted: 04/15/2020] [Indexed: 12/24/2022] Open
Abstract
A novel cosegregating splice site variant in the Dynactin-1 (DCTN1) gene was discovered by Next Generation Sequencing (NGS) in a family with a history of bipolar disorder (BD) and major depressive diagnosis (MDD). Psychiatric illness in this family follows an autosomal dominant pattern. DCTN1 codes for the largest dynactin subunit, namely p150Glued, which plays an essential role in retrograde axonal transport and in neuronal autophagy. A GT→TT transversion in the DCTN1 gene, uncovered in the present work, is predicted to disrupt the invariant canonical splice donor site IVS22 + 1G > T and result in intron retention and a premature termination codon (PTC). Thus, this splice site variant is predicted to trigger RNA nonsense-mediated decay (NMD) and/or result in a C-terminal truncated p150Glued protein (ct-p150Glued), thereby negatively impacting retrograde axonal transport and neuronal autophagy. BD prophylactic medications, and most antipsychotics and antidepressants, are known to enhance neuronal autophagy. This variant is analogous to the dominant-negative GLUED Gl1 mutation in Drosophila, which is responsible for a neurodegenerative phenotype. The newly identified variant may reflect an autosomal dominant cause of psychiatric pathology in this affected family. Factors that affect alternative splicing of the DCTN1 gene, leading to NMD and/or ct-p150Glued, may be of fundamental importance in contributing to our understanding of the etiology of BD as well as MDD.
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3
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Zotti MD, Formaggio F, Crisma M, Peggion C, Moretto A, Toniolo C. Handedness preference and switching of peptide helices. Part I: Helices based on protein amino acids. J Pept Sci 2014; 20:307-22. [DOI: 10.1002/psc.2638] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 03/17/2014] [Accepted: 03/18/2014] [Indexed: 12/20/2022]
Affiliation(s)
- Marta De Zotti
- Department of Chemistry; University of Padua; Padua Italy
| | | | | | | | | | - Claudio Toniolo
- Department of Chemistry; University of Padua; Padua Italy
- ICB, Padua Unit; CNR; Italy
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4
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Basu D, Tian Y, Bhandari J, Jiang JR, Hui P, Johnson RL, Mishra RK. Effects of the dopamine D2 allosteric modulator, PAOPA, on the expression of GRK2, arrestin-3, ERK1/2, and on receptor internalization. PLoS One 2013; 8:e70736. [PMID: 23940634 PMCID: PMC3735488 DOI: 10.1371/journal.pone.0070736] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 06/26/2013] [Indexed: 11/19/2022] Open
Abstract
The activity of G protein-coupled receptors (GPCRs) is intricately regulated by a range of intracellular proteins, including G protein-coupled kinases (GRKs) and arrestins. Understanding the effects of ligands on these signaling pathways could provide insights into disease pathophysiologies and treatment. The dopamine D2 receptor is a GPCR strongly implicated in the pathophysiology of a range of neurological and neuropsychiatric disorders, particularly schizophrenia. Previous studies from our lab have shown the preclinical efficacy of a novel allosteric drug, 3(R)- [(2(S)-pyrrolidinylcarbonyl)amino]-2-oxo-1-pyrrolidineacetamide (PAOPA), in attenuating schizophrenia-like behavioural abnormalities in rodent models of the disease. As an allosteric modulator, PAOPA binds to a site on the D2 receptor, which is distinct from the endogenous ligand-binding site, in order to modulate the binding of the D2 receptor ligand, dopamine. The exact signaling pathways affected by this allosteric modulator are currently unknown. The objectives of this study were to decipher the in vivo effects, in rats, of chronic PAOPA administration on D2 receptor regulatory and downstream molecules, including GRK2, arrestin-3 and extracellular receptor kinase (ERK) 1/2. Additionally, an in vitro cellular model was also used to study PAOPA’s effects on D2 receptor internalization. Results from western immunoblots showed that chronic PAOPA treatment increased the striatal expression of GRK2 by 41%, arrestin-3 by 34%, phospho-ERK1 by 51% and phospho-ERK2 by 36%. Results also showed that the addition of PAOPA to agonist treatment in cells increased D2 receptor internalization by 33%. This study provides the foundational evidence of putative signaling pathways, and changes in receptor localization, affected by treatment with PAOPA. It improves our understanding on the diverse mechanisms of action of allosteric modulators, while advancing PAOPA’s development into a novel drug for the improved treatment of schizophrenia.
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Affiliation(s)
- Dipannita Basu
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada
| | - Yuxin Tian
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada
| | - Jayant Bhandari
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada
| | - Jian Ru Jiang
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada
| | - Patricia Hui
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada
| | - Rodney L. Johnson
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Ram K. Mishra
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada
- * E-mail:
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5
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Bhagwanth S, Mishra RK, Johnson RL. Development of peptidomimetic ligands of Pro-Leu-Gly-NH(2) as allosteric modulators of the dopamine D(2) receptor. Beilstein J Org Chem 2013; 9:204-14. [PMID: 23400263 PMCID: PMC3566759 DOI: 10.3762/bjoc.9.24] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 12/24/2012] [Indexed: 12/24/2022] Open
Abstract
A variety of stable, small-molecule peptidomimetic ligands have been developed to elucidate the mechanism by which the neuropeptide Pro-Leu-Gly-NH2 (PLG) modulates dopaminergic neurotransmission. Photoaffinity labeling ligands based upon PLG peptidomimetics have been used to establish that PLG binds to the D2 dopamine receptor at a site that is different from the orthosteric site, thus making PLG and its peptidomimetics allosteric modulators of the dopamine receptor. Through the design, synthesis and pharmacological evaluation of conformationally constrained peptidomimetics containing lactam, bicyclic, and spiro-bicyclic scaffolds, support was provided for the hypothesis that the bioactive conformation of PLG is a type II β-turn. In addition, studies with peptidomimetics designed to mimic either a type VI β-turn or polyproline II helix conformation yielded molecules that were able to modulate dopamine receptors because of their ability to place the carboxamide NH2 pharmacophore in the same topological space as that seen in the type II β-turn. Extensive studies with the spiro-bicyclic PLG peptidomimetics also established that both positive and negative modes of modulation were possible for the same series of peptidomimetics simply as a result of minor differences in the stereochemistry about the bridgehead carbon within the scaffold. This information was used to transform existing positive modulators into negative modulators, which demonstrated that small structural changes in the spiro-bicyclic dopamine receptor modulators are capable of causing major changes in the modulatory activity of PLG peptidomimetics.
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Affiliation(s)
- Swapna Bhagwanth
- Department of Medicinal Chemistry, University of Minnesota, 308 Harvard Street SE, Minneapolis, MN 55455, USA
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6
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Jlalia I, Lensen N, Chaume G, Dzhambazova E, Astasidi L, Hadjiolova R, Bocheva A, Brigaud T. Synthesis of an MIF-1 analogue containing enantiopure (S)-α-trifluoromethyl-proline and biological evaluation on nociception. Eur J Med Chem 2013; 62:122-9. [PMID: 23353749 DOI: 10.1016/j.ejmech.2012.12.041] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 12/19/2012] [Accepted: 12/23/2012] [Indexed: 11/16/2022]
Abstract
The synthesis and the effect of a novel MIF-1 analogue on nociception during acute pain in rat model are reported. The synthesis of this enantiopure trifluoromethyl group containing tripeptide was performed through a peptide coupling reaction between the HCl. Leu-Gly-NH2 and the (S)-α-Tfm-proline. The analgesic effect of the CF3-(MIF-1) 2 has been evaluated in vivo on rat model by paw pressure (PP) and hot plate (HP) tests and compared to the native peptide MIF-1. Highest analgesic effect was observed with CF3-(MIF-1) 2 only in PP test. In order to study the mechanisms of nociception induced by the studied peptides, the involvement of the opioid and the nitric oxideergic systems was investigated. The results are in favor of a participation of both system since pretreatment, 20 min before injection of the CF3-(MIF-1) 2, with the non-competitive antagonist of opiate receptors naloxone, the nitric oxide synthase (NOS) inhibitor l-N(G)-nitroarginine ester (l-NAME) or the nitric oxide (NO) donor l-arginine (l-Arg) significantly decreased the pain perception in PP and HP tests.
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Affiliation(s)
- Ibtissem Jlalia
- Laboratoire SOSCO, Université de Cergy-Pontoise, EA 4505, 5 Mail Gay Lussac, Neuville sur Oise, 95000 Cergy-Pontoise Cedex, France
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7
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Bhagwanth S, Mishra S, Daya R, Mah J, Mishra RK, Johnson RL. Transformation of Pro-Leu-Gly-NH2 peptidomimetic positive allosteric modulators of the dopamine D2 receptor into negative modulators. ACS Chem Neurosci 2012; 3:274-84. [PMID: 22860194 DOI: 10.1021/cn200096u] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Accepted: 01/13/2012] [Indexed: 11/28/2022] Open
Abstract
The synthesis of dimethyl derivatives of 5.6.5 spiro bicyclic lactam Pro-Leu-Gly-NH(2) peptidomimetics was carried out to test the hypothesis that by placing methyl groups on the β-methylene carbon of the thiazolidine ring steric bulk would be introduced into the topological space that the β-methylene carbon is believed to occupy in the negative allosteric modulators of the dopamine D(2) receptor. With such a modification, a positive allosteric modulator would be converted into a negative allosteric modulator. This hypothesis was shown to be correct as 3a and 4a where found to be negative allosteric modulators, whereas their unmethylated derivatives were positive allosteric modulators of the dopamine D(2) receptor.
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Affiliation(s)
- Swapna Bhagwanth
- Department of Medicinal Chemistry, University of Minnesota, 308 Harvard Street SE, Minneapolis,
Minnesota 55455, United States
| | - Satyendra Mishra
- Department of Medicinal Chemistry, University of Minnesota, 308 Harvard Street SE, Minneapolis,
Minnesota 55455, United States
| | - Ritesh Daya
- Department of Psychiatry and
Behavioral Neurosciences, McMaster University, 1200 Main Street W, Hamilton, Ontario L8N 3Z5, Canada
| | - Jordan Mah
- Department of Psychiatry and
Behavioral Neurosciences, McMaster University, 1200 Main Street W, Hamilton, Ontario L8N 3Z5, Canada
| | - Ram K. Mishra
- Department of Psychiatry and
Behavioral Neurosciences, McMaster University, 1200 Main Street W, Hamilton, Ontario L8N 3Z5, Canada
| | - Rodney L. Johnson
- Department of Medicinal Chemistry, University of Minnesota, 308 Harvard Street SE, Minneapolis,
Minnesota 55455, United States
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8
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Ung P, Winkler DA. Tripeptide Motifs in Biology: Targets for Peptidomimetic Design. J Med Chem 2011; 54:1111-25. [DOI: 10.1021/jm1012984] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Phuc Ung
- CSIRO Materials Science and Engineering, Bag 10, Clayton South MDC 3169, Australia
- Monash Institute of Pharmaceutical Science, Parkville 3152, Australia
| | - David A. Winkler
- CSIRO Materials Science and Engineering, Bag 10, Clayton South MDC 3169, Australia
- Monash Institute of Pharmaceutical Science, Parkville 3152, Australia
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9
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Raghavan B, Skoblenick KJ, Bhagwanth S, Argintaru N, Mishra RK, Johnson RL. Allosteric modulation of the dopamine D2 receptor by Pro-Leu-Gly-NH2 peptidomimetics constrained in either a polyproline II helix or a type II beta-turn conformation. J Med Chem 2009; 52:2043-51. [PMID: 19271750 DOI: 10.1021/jm801575w] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Type II beta-turn mimics and polyproline II helix mimics based upon diastereoisomeric 5.6.5 spiro bicyclic scaffolds have provided two pairs of Pro-Leu-Gly-NH(2) (PLG) peptidomimetics with contrasting dopamine receptor modulating activities. Compounds 1a and 3a were found to be positive allosteric modulators of the dopamine receptor, while the corresponding diastereoisomeric compounds 1b and 3b provided the first PLG peptidomimetics with the ability to decrease the binding of agonists to the dopamine receptor. The positive allosteric modulating activity of 3a supported the hypothesis that a polyproline II helix conformation is the bioactive conformation for the PLG analogue Pro-Pro-Pro-NH(2). The results also show that a change in the bridgehead chirality of the 5.6.5 scaffold brings about opposite effects in terms of the modulation of the dopamine receptor.
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Affiliation(s)
- Bhooma Raghavan
- Department of Medicinal Chemistry, University of Minnesota, SE, Minneapolis, Minnesota 55455, USA
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10
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Saitton S, Del Tredici AL, Saxin M, Stenström T, Kihlberg J, Luthman K. Synthesis and evaluation of novel pyridine based PLG tripeptidomimetics. Org Biomol Chem 2008; 6:1647-54. [PMID: 18421399 DOI: 10.1039/b718058f] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Analogues of the pyridine based PLG (Pro-Leu-Gly-NH(2)) peptidomimetic were synthesized and evaluated as dopamine modulating agents. Modifications in the position corresponding to the leucine side chain in PLG afforded derivatives , and , substituted with H, Me and Bn instead of the isobutyl group, respectively. Changes in the proline residue produced derivative , substituted with a symmetrical piperidine ring instead of the pyrrolidine ring and , in which the pyrrolidine ring is connected to the pyridine ring via a hydroxymethyl group instead of a keto function. The peptidomimetics were tested for their ability to enhance the maximal effect of N-propylapomorphine (NPA) at dopamine D2 receptors in the functional cell-based R-SAT assay. Compounds , , and , produced a statistically significant increase in the maximal NPA response at 10 nM (117 +/- 6%, 118 +/- 6%, and 116 +/- 3%, respectively), which is similar to the effect of PLG in this assay, whereas was able to potentiate the response to a similar extent at 1 nM concentration (115 +/- 5%). All derivatives produced a bell-shaped dose-response curve and none of the compounds were active at the D2 receptor alone, which indicates that the mechanism behind the activity of both the pyridine based mimetics and PLG is the same. Interestingly, l-Pro-d-Leu-Gly-NH(2) was found to be more potent than PLG and produced a 119 +/- 1% increase in the NPA response at 1 nM.
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Affiliation(s)
- Stina Saitton
- Göteborg University, Department of Chemistry, Medicinal Chemistry, SE-412 96, Göteborg, Sweden
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11
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Vartak AP, Skoblenick K, Thomas N, Mishra RK, Johnson RL. Allosteric modulation of the dopamine receptor by conformationally constrained type VI beta-turn peptidomimetics of Pro-Leu-Gly-NH2. J Med Chem 2007; 50:6725-9. [PMID: 18052024 DOI: 10.1021/jm070895r] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A peptidomimetic of Pro-Leu-Pro-NH2, 7, possessing an indolizidinone type VI beta-turn mimic was synthesized via improved high-yielding protocols for the preparation and Cbz protection of alpha-allylproline. Bicyclic peptidomimetic 7 and spirobicylic peptidomimetic 8 enhanced the binding of [3H] N-propylnorapomorphine to dopamine receptors indicating that a type VI beta-turn is a possible bioactive conformation of the homochiral Pro-Leu-Pro-NH2 and Pro-Pro-Pro-NH 2 analogues of Pro-Leu-Gly-NH2 at the dopamine receptor allosteric regulatory site.
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Affiliation(s)
- Ashish P Vartak
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis 55455-0343, USA
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12
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Dolado I, Nieto J, Saraiva MJM, Arsequell G, Valencia G, Planas A. Kinetic assay for high-throughput screening of in vitro transthyretin amyloid fibrillogenesis inhibitors. ACTA ACUST UNITED AC 2006; 7:246-52. [PMID: 15762752 DOI: 10.1021/cc049849s] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Stabilization of tetrameric transthyretin (TTR) by binding of small ligands is a current strategy aimed at inhibiting amyloid fibrillogenesis in transthyretin-associated pathologies, such as senile systemic amyloidosis (SSA) and familial amyloidotic polyneuropathy (FAP). A kinetic assay is developed for rapid evaluation of compounds as potential in vitro inhibitors in a high-throughput screening format. It is based on monitoring the time-dependent increase of absorbance due to turbidity occurring by acid-induced protein aggregation. The method uses the highly amyloidogenic Y78F mutant of human transthyretin (heterogously expressed in Escherichia coli cells). Initial rates of protein aggregation at different inhibitor concentrations follow a monoexponential dose-response curve from which inhibition parameters are calculated. For the assay development, thyroid hormones and nonsteroidal antiinflamatory drugs were chosen among other reference compounds. Some of them are already known to be in vitro inhibitors of TTR amyloidogenesis. Analysis time is optimized to last 1.5 h, and the method is implemented in microtiter plates for screening of libraries of potential fibrillogenesis inhibitors.
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Affiliation(s)
- Ignacio Dolado
- Laboratory of Biochemistry, Institut Químic de Sarrià, Universitat Ramon Llull, E-08017 Barcelona, Spain
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13
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IJzerman AP, Wijngaarden IV, Soudijn W. Allosteric modulation of G-protein-coupled receptors. Expert Opin Ther Pat 2005. [DOI: 10.1517/13543776.11.12.1889] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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14
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Saitton S, Del Tredici AL, Mohell N, Vollinga RC, Boström D, Kihlberg J, Luthman K. Design, Synthesis and Evaluation of a PLG Tripeptidomimetic Based on a Pyridine Scaffold. J Med Chem 2004; 47:6595-602. [PMID: 15588094 DOI: 10.1021/jm049484q] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A 2,3,4-substituted pyridine derivative has been identified as a potential tripeptidomimetic scaffold. The design of the scaffold was based on conformational and electrostatic comparisons with a natural tripeptide. The scaffold has been used in the synthesis of a Pro-Leu-Gly-NH2 (PLG) mimetic. The different substituents in the 2-, 3-, and 4-positions of the pyridine ring were introduced via an aromatic nucleophilic substitution reaction, a "halogen-dancing" reaction, and a Grignard coupling of a Boc-protected amino aldehyde, respectively. The synthetic route involves eight steps and provides the mimetic in 20% overall yield. The pyridine based PLG-mimetic was evaluated for its ability to enhance the maximum response of the dopamine agonist N-propylapomorphine (NPA) at human D2 receptors using a cell based assay (the R-SAT assay). The dose-response curve of the mimetic was found to exhibit a down-turn phase, similar to that of PLG. In addition, the mimetic was more potent than PLG to enhance the NPA response; the maximum response was found to be 146% at 10 nM concentration, as compared to 115% for PLG at the same concentration. Interestingly, conformational analysis by molecular modeling showed that the pyridine mimetic cannot adopt a type II beta-turn conformation that previously has been suggested to be the bioactive conformation of PLG.
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Affiliation(s)
- Stina Saitton
- Department of Chemistry, Medicinal Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden
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15
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Palomo C, Aizpurua JM, Benito A, Miranda JI, Fratila RM, Matute C, Domercq M, Gago F, Martin-Santamaria S, Linden A. Development of a New Family of Conformationally Restricted Peptides as Potent Nucleators of β-Turns. Design, Synthesis, Structure, and Biological Evaluation of a β-Lactam Peptide Analogue of Melanostatin. J Am Chem Soc 2003; 125:16243-60. [PMID: 14692766 DOI: 10.1021/ja038180a] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Novel enantiopure (i)-(beta-lactam)-(Gly)-(i+3) peptide models, defined by the presence of a central alpha-alkyl-alpha-amino-beta-lactam ring placed as the (i+1) residue, have been synthesized in a totally stereocontrolled way by alpha-alkylation of suitable N-[bis(trimethylsilyl)methyl]-beta-lactams. The structural properties of these beta-lactam pseudopeptides have been studied by X-ray crystallography, Molecular Dynamics simulation, and NOESY-restrained NMR simulated annealing techniques, showing a strong tendency to form stable type II or type II' beta-turns either in the solid state or in highly coordinating DMSO solutions. Tetrapeptide models containing syn- or anti-alpha,beta-dialkyl-alpha-amino-beta-lactam rings have also been synthesized and their conformations analyzed, revealing that alpha-alkyl substitution is essential for beta-turn stabilization. A beta-lactam analogue of melanostatin (PLG amide) has also been prepared, characterized as a type-II beta-turn in DMSO-d6 solution, and tested by competitive binding assay as a dopaminergic D2 modulator in rat neuron cultured cells, displaying moderate agonist activity in the micromolar concentration range. On the basis of these results, a novel peptidomimetic design concept, based on the separation of constraint and recognition elements, is proposed.
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Affiliation(s)
- Claudio Palomo
- Departamento de Química Orgánica I. Facultad de Química, Universidad del País Vasco, Apdo. 1072, 20080 San Sebastián, Spain.
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Orena M, Galeazzi R, Martelli G, Mobbili G, Panagiotaki M. A Stereoselective Approach to Both 3,4-trans-Disubstituted Pyrrolidin-2-ones and Pyrrolidines. A Convenient Synthesis of (3R,4R)-4-Benzyl-3-pyrrolidinecarboxylic Acid. HETEROCYCLES 2003. [DOI: 10.3987/com-03-9854] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Herdeis C, Kelm B. A stereoselective synthesis of 3-substituted (S)-pyroglutamic and glutamic acids via OBO ester derivatives. Tetrahedron 2003. [DOI: 10.1016/s0040-4020(02)01490-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Evans MC, Johnson RL. Triproline Analogues of Pro-Leu-Gly-NH2 with Pro/Leu and Pro/Phe Chimeric Amino Acids in Position 2. Tetrahedron 2000. [DOI: 10.1016/s0040-4020(00)00887-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Lashuel HA, Wurth C, Woo L, Kelly JW. The most pathogenic transthyretin variant, L55P, forms amyloid fibrils under acidic conditions and protofilaments under physiological conditions. Biochemistry 1999; 38:13560-73. [PMID: 10521263 DOI: 10.1021/bi991021c] [Citation(s) in RCA: 142] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The L55P transthyretin (TTR) familial amyloid polyneuropathy-associated variant is distinct from the other TTR variants studied to date and the wild-type protein in that the L55P tetramer can dissociate to the monomeric amyloidogenic intermediate and form fibril precursors under physiological conditions (pH 7.0, 37 degrees C). The activation barrier associated with L55P-TTR tetramer dissociation is lower than the barrier for wild-type transthyretin dissociation, which does not form fibrils under physiological conditions. The L55P-TTR tetramer is also very sensitive to acidic conditions, readily dissociating to form the monomeric amyloidogenic intermediate between pH 5.5-5.0 where the wild-type TTR adopts a nonamyloidogenic tetrameric structure. The formation of the L55P monomeric amyloidogenic intermediate involves subtle tertiary structural changes within the beta-sheet rich subunit as discerned from Trp fluorescence, circular dichroism analysis, and ANS binding studies. The assembly of the L55P-TTR amyloidogenic intermediate at physiological pH (pH 7.5) affords protofilaments that elongate with time. TEM studies suggest that the entropic barrier associated with filament assembly (amyloid fibril formation) is high in vitro, amyloid being defined by the laterally assembled four filament structure observed by Blake upon isolation of "fibrils" from the eye of a FAP patient. The L55P-TTR protofilaments formed in vitro bind Congo red and thioflavin T (albeit more weakly than the fibrils produced at acidic pH), suggesting that the structure observed probably represents an amyloid precursor. The structural continuum from misfolded monomer through protofilaments, filaments, and ultimately fibrils must be considered as a possible source of pathology associated with these diseases.
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Affiliation(s)
- H A Lashuel
- Department of Chemistry, The Skaggs Institute of Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, USA
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