Radiochemical examination of transthyretin (TTR) brain penetration assisted by iododiflunisal, a TTR tetramer stabilizer and a new candidate drug for AD

It is well settled that the amyloidogenic properties of the plasma protein transporter transthyretin (TTR) can be modulated by compounds that stabilize its native tetrameric conformation. TTR is also present in cerebrospinal fluid where it can bind to Aβ-peptides and prevent Aβ aggregation. We have previously shown that treatment of Alzheimer’s Disease (AD) model mice with iododiflunisal (IDIF), a TTR tetramer stabilizing compound, prevents AD pathologies. This evidence positioned IDIF as a new lead drug for AD. In dissecting the mechanism of action of IDIF, we disclose here different labeling strategies for the preparation of 131I-labeled IDIF and 131I- and 124I-labeled TTR, which have been further used for the preparation of IDIF-TTR complexes labeled either on the compound or the protein. The biodistribution of all labeled species after intravenous administration has been investigated in mice using ex vivo and in vivo techniques. Our results confirm the capacity of TTR to cross the blood brain barrier (BBB) and suggest that the formation of TTR-IDIF complexes enhances BBB permeability of both IDIF and TTR. The increased TTR and IDIF brain concentrations may result in higher Aβ-peptide sequestration capacity with the subsequent inhibition of AD symptoms as we have previously observed in mice. © 2019, The Author(s).The work was supported by a grant from the Fundació Marató de TV3 (Neurodegenerative Diseases Call, Project Reference 20140330-31-32-33-34, http://www.ccma.cat/tv3/marato/en/ projectes-financats/2013/212/). The group at CIC biomaGUNE also acknowledges MINECO (Spain) for funding through Grant CTQ2017-87637-R. I. Cardoso worked under the Investigator FCT Program which is financed by national funds through the Foundation for Science and Technology (FCT, Portugal) and co-financed by the European Social Fund (ESF) through the Human Potential Operational Programme (HPOP), type 4.2 - Promotion of Scientific Employment.Peer reviewe

Les molècules que modulen el dolor. Analgèsia i drogodependència, vint-i-cinc anys després del descobriment de les encefalines

7 pages, 8 figures.[CAT] La sensació de dolor és una de les experiències comunes a tot ésser humà. Entre els estímuls dolorosos, n’hi ha que estan adreçats a mantenir la integritat del cos advertint la presència d’agressions externes, però és sovint desitjable poder-los controlar, especialment quan són de naturalesa crònica. S’ha demostrat que el control del dolor no és una tasca fàcil, perquè, malgrat el gran esforç investigador fet en els darrers cent anys per tal de trobar noves substàncies analgèsiques, el millor remei continua essent avui la morfina. Tanmateix les expectatives derivades del descobriment dels opiacis endògens, les encefalines, no han conduït tampoc al desenvolupament d’un analgèsic ideal lliure de problemes greus com la tolerància i l’addicció.[ENG] The sensation of pain is a common human experience. Although pain stimuli also serve as a warning system against external body aggressions, it is always desirable to control them, especially when they are chronic. During the past century, a great deal of effort was devoted to finding new substances to alleviate pain. However, this proved to be a difficult task and, to date, morphine, is the best remedy. Moreover, the expectations raised from the discovery of the endogenous opioids, the enkephalins, have not been fulfilled and the ideal analgesic lacking tolerance and addictive effects is still eagerly awaited.Peer reviewe

Binding profile of the endogenous novel heptapeptide Met-enkephalin-Gly-tyr in zebrafish and rat brain

6 pages, 3 figures, 2 tables.-- PMID: 15901806 [PubMed].-- Printed version published Aug 2005.Zebrafish is considered a model organism, not only for the study of the biological functions of vertebrates but also as a tool to analyze the effects of some drugs or toxic agents. Five opioid precursor genes homologous to the mammalian opioid propeptide genes have recently been identified; one of these, the zebrafish proenkephalin, codes a novel heptapeptide, the Met-enkephalin-Gly-Tyr (MEGY). To analyze the pharmacological properties of this novel ligand, we have labeled it with tritium ([3H]MEGY). In addition, we have also synthesized two analogs: (D-Ala2)-MEGY (Y-D-Ala-GFMGY) and (D-Ala2, Val5)-MEGY (Y-D-Ala-GFVGY). The binding profile of these three agents has been studied in zebrafish and rat brain membranes. [3H]MEGY presents one binding site in zebrafish, as well as in rat brain membranes, although it shows a slight higher affinity in zebrafish brain. The observed saturable binding is displaced by naloxone, thus confirming the opioid nature of the binding sites. Competition binding assays indicate that the methionine residue is essential for high-affinity binding of MEGY and probably of other peptidic agonists in zebrafish, whereas the change of a Gly for a D-Ala does not dramatically affect the ligand affinity. Our results show that the percentage of [3H]MEGY displaced by all the ligands studied is higher than 100%, thus inferring that naloxone (used to determine nonspecific binding) does not bind to all the sites labeled by [3H]MEGY. Therefore, we can deduct that some of the MEGY binding sites should not be considered classical opioid sites.This study was supported by Ministerio de Educación y Ciencia (SAF2004-05144), Junta de Castilla y León (SA031/03/00B), and Hungarian National Scientific Research Foundation (Hungary) Grant T046514Peer reviewe

A highly toxic morphine-3-glucuronide derivative

4 pages, 1 figure, 4 tables.-- 15012991 [PubMed].-- Printed version published Feb 23, 2004.By the coupling of octylamine to the uronic acid function of morphine-3-glucuronide (M3G) a new glycoconjugate (morphine-3-octylglucuronamide, M3GOAM) was prepared. When assayed in both rats and mice up to ng/kg (ip) doses none of the animals survived. The aliphatic octyl chain may be the lethal factor since a closely related derivative (M3GNH2), was not toxic and showed similar opioid antagonist properties than naloxone.A morphine-3-glucuronide conjugate to octylamine is a lethal compound even at ng/kg doses. However, its closely related amide analogue lacking the octyl chain acts as opioid antagonist in a similar pattern than naloxone.This work was supported by grants EUREKA-391 (Glycotrans) and 96-0175 from Centro para el Desarrollo Tecnológico Industrial (C.D.T.I.).Peer reviewe

Selección artículos de divulgación para la exposición "La ciencia según Forges"

Este apartado recoge las fechas de publicación en el diario El País de las viñetas incluidas en la exposición. Además, se acompañan de un código que permite acceder a más información sobre las cuestiones científicas y tecnológicas abordadas por Forges.Peer reviewe

Regioselective postsynthetic modification of phenylalanine side chains of peptides leading to uncommon ortho-iodinated analogues

5 pages, 4 schemes, 3 tables.-- Availcable online Dec 29, 2003.-- Supporting information available at: http://www.wiley-vch.de/contents/jc_2002/2004/z52464_s.pdfThis research was partially supportedby the Spanish MCYT (Grant BQU2001-3853) andthe FundaciGn la Caixa (Project Reference 00/ 010-00 of the IV Program of Grants for Research on Neurodegenarative Diseases of the FundaciGn La Caixa).Peer reviewe

Poly-α-amino acids acting as synthetic enzymes on a epoxidation reaction: A physicochemical study of the catalyst

The asymmetric epoxidation of chalcone in the presence of several poly-α-amino acids acting as stereoselective catalysts in a tricomponent system (aqueous phase/organic solvent/polymer) takes place with excellent chemical and optical yields. A better knowledge of the mechanism of catalysis would be very useful to extend the application of such pseudoenzymatic reactions. According to this, emulsion stability studies and film compression measurements, using different poly-α-amino acids in several solvent systems have been undertaken. The results obtained show that the catalytic activity of the polymers is exercised throughout a monolayer mechanism and such activity is a function of the polymer nature as well as the polymer conformation induced by the organic solvent. © 1986.Peer reviewe

Procedimiento de síntesis de análogos glicosados de la sustancia P

Fecha de presentación nacional 08.03.1989.-- Titular: Consejo Superior de Investigaciones Científicas (CSIC).El procedimiento de síntesis se realiza en las etapas siguientes: Primera, consiste en efectuar el acoplamiento entre la N - terbutiloxicarbonil - L - fenilalanina y el éster metálico de la L - fenilalanina; en la segunda se lleva a cabo la saponificación del primero y la hidrogenación catalítica del segundo; en la tercera etapa se elimina el grupo protector terbutiloxicarbonilo; en la cuarta etapa se lleva a cabo la condensación entre el tripéptido y el dipéptido; y en la quinta etapa se procede a la condensación entre el pentapéptido con el resto del ácido glutámico. Dicho procedimiento incrementa la afinidad y selectividad del péptido por sus receptores, presentando un amplio espectro de acciones biológicas, tales como la contracción de varios músculos lisos, el incremento de la secreción salivar y pancreática, etc.Peer reviewe

Lipoenkephalins: A Study Of The Surface Active And Pharmacological Properties Of These New Morphine-Like Peptides

By modifying the physicochemical character of naturally occurring enkephalines, a parallelism between physicochemical behavior and pharmacological activity has been found. This was achieved by introducing alkyl residues of different chain length in position 1 or 5 on the enkephalin sequence. These kinds of substances can be referred to as lipoenkephalins and from a physicochemical point of view can be considered as surface active aaents. On the other hand, as biological activity is greatly dependent on the conformation or orientation adopted by the molecule, we have also tried to investigate possible conformational or orientation changes when increasing the hydrophobic residue by means of optical rotation measurements and compression isotherm determinations. Finally, as the enkephalin molecule itself suffers an extremely rapid inactivation in brain tissues due to the proteolitic enzyme action, several tests to check the resistance of lipoenkephalins to enzymatic hydrolysis have been carried out, allowing us to confirm that the hydrophobic residue prevents that action.Peer reviewe

Kinetic assay for high-throughput screening of in vitro transthyretin amyloid fibrillogenesis inhibitors

7 pages, 4 figures, 1 scheme, 2 tables.-- PMID: 15762752 [PubMed].-- Printed version published Mar 2005.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.This work was supported by a grant from Fundació La Caixa (4th Program for Research on Neurodegenerative Diseases, year 2000), and Grant EET2002-05157 from the Ministerio de Ciencia y Tecnología, Spain.Peer reviewe