Alzheimer-kór elleni béta-amiloid antagonista peptidek előállítása és vizsgálata = Synthesis and investigation of beta-amyloid peptide antagonists against Alzheimer`s disease

Szilárdfázisú peptid szintézis módszer és Boc-stratégia alkalmazásával állítottuk elő az új, β-amiloid antagonista peptideket. Tisztítás után igazoltuk a szerkezetüket és tisztaságukat. Előállítottuk: 1) a korábban neuroprotektív hatást mutató vegyületünk, a propionil-RIIGL-NH2 pentapeptid 11 szabad N-terminálisú és 22 acilezett, valamint 23 tripeptid és 3 dipeptid származékát és 2) az irodalomban „beta sheet breaker” (BSB) hatásúnak leírt LPFFD pentapeptid analógjait: 19 penta- és 75 tetrapeptid ill peptidomimetikum származékát. A származékok D-aminosavakat, nem természetes aminosavakat, aminokat és karbonsav származékokat tartalmaznak. Kidolgoztuk az Aß(1-42) racionális szintézisét, amellyel lehetővé vált nagy mennyiségű Aß(1-42) előállítása a biológiai vizsgálatok számára. A β-amiloid antagonista peptidek neuroprotektív hatását differenciált humán neuroblasztóma sejt tenyészeten (SH-SY5Y) és primer sejtkultúrán MTT teszttel és mikrofluoreszcenciás imaging technikával (in vitro) és elektrofiziológiai módszerrel in vivo körülmények között vizsgáltuk meg. Mivel voltak közöttük kiemelkedő neuroprotektív hatású vegyületek, a 75 új tetrapeptid- és peptidomimetikumra a Biogal-TEVA gyárral közös szabadalmat jelentettünk be. A P29 és P59 kódszámú vegyületek bármelyike az Alzheimer-kór potenciális gyógyszere lehet, amely a kór progresszióját megállítani vagy legalább lassítani képes. | The new antagonistic Aß peptides were synthesized by solid phase method using Boc-strategy. After purification with RP-HPLC, their structure and purity was confirmed by analytical HPLC, amino acid analysis, and ESI-MS measurements. We synthesized: 1) eleven pentapeptides with free N-terminus, 22 acylated analogues, 23 tri-, and 3 dipeptides. These peptides are derivatives of propionyl-RIIGL-NH2 which previously showed neuroprotective effect against Aß(1-42). 2) the analogues of the known "beta sheet breaker" (BSB) LPFFD: 19 penta- and 75 tetrapeptides and peptidomimetics. In order to increase resistance against enzymes, the derivatives had D- and unnatural amino acids, amines, and derivatives of carboxylic acids. We worked out the rationale synthesis of Aß(1-42) to get large quantity of this peptide for biological tests. The neuroprotective effects of the new antagonistic Aß peptides were tested by MTT test and microfluorescence imaging assay (in vitro) on differentiated human neuroblastoma cells (SH-SY5Y) and on primary cell culture and by electrophysiological mesurements in vivo. Together with Biogal-Teva Company, we filed a patent application for the 75 tetrapeptide and peptidomimetics as some of them were highly active both in vitro and in vivo. Compounds P29 and P59 are potential drugs against Alzheimer's disease since they might stop or delay the progression of the disease

Endothelium-dependent vasorelaxant and anti-aggregatory effect and mechanism of action of some antifibrinogen RGD (Arg-Gly-Asp-containing) peptides

Vasorelaxation caused by some antifibrinogen RGD (Arg-Gly-Asp-containing) peptides and their basic mechanism of action was studied on rabbit isolated thoracic aortic rings preconstricted with 0.25 mu M phenylephrine. GRGDS (Gly-Arg-Gly-Asp-Ser-OH) and RGDV (Arg-Gly-Asp-Val-OH) caused dose-dependent relaxation. RGDS (Arg-Gly-Asp-Ser-OH) had a biphasic effect (a transient relaxation followed by a contraction) while GRGDS-[SE] (Gly-Arg-Gly-Asp-Ser(SO3)-OH) did not change the isometric tone of precontracted aortic preparations. GRGDS and RGDV exerted no relaxing effect on endothelium-denuded blood vessels suggesting that the vascular action of these peptides was entirely dependent on the presence of functionally intact endothelium. L-N-G-Nitro-arginine (30 mu M) attenuated the relaxation induced by GRGDS and abolished that induced by RGDV. All of the four RGD congeners inhibited ADP-induced aggregation of human platelets. These findings indicate that the relaxant effect of RGDV is mediated exclusively by the nitric oxide pathway, but GRGDS could cause, besides nitric oxide release, the release of another substance which is different from nitric oxide. Because the rank order of the vasorelaxant potencies of RGD peptides differed from that found for their anti-aggregatory activities, a vascular effector mechanism mediated by an ROD-recognizing structure other than the known glycoprotein IIb/ma-like ROD-binding site is suggested

Peptidek és fehérjék, és peptid-nukleinsavak szintézise, szerkezetvizsgálata és biológiai szerepe = Synthesis, structure investigation and biological role of peptides, proteins and peptide nucleic acids

A neurodegeneratív betegségek kialakulásának jórészt közös mechanizmusa van: egy polipeptid vagy fehérje átalakul oldhatatlan aggregátummá, ez kicsapódik az idegsejtek között vagy a sejt belsejében és megakadályozza az ingerületvezetést, majd elpusztítja az idegsejteket. Alzheimer-kór modellkísérletekben igazoltuk, hogy a toxikus polipeptid (beta-amiloid 1-42) két fő aggregációs formája (Abeta-oligomer, ill. fibrillum) más receptorokon fejti ki hatását. A toxikus aggregátumok kialakulásában fontos szerepet játszhatnak a nehézfémionok, pl. a Zn2+, így a cink-kelátorok (pl. ACE-inhibitorok) az Alzheimer-kór potenciális gyógyszerei. Egy másik vegyületcsoport (peptidmimetikumok) úgy védi meg az idegsejteket, hogy beborítja az Abeta-aggregátumok felszínét és megakadályozza a kölcsönhatást a membránfehérjékkel (szabadalmi bejelentés). Gyógyszerek sejtbe jutását megkönnyítő, a sejtmembránon áthaladó peptid vektorokat terveztünk (penetratin származékok) és igazoltuk hatásmechanizmusukat (szabadalmi bejelentés). Egy humán beta-galaktozid kötő lektint (galektin-1) vizsgálva megállapítottuk, hogy igen hatásosan gátolja a gyulladásos és autoimmun folyamatokat, ez új immunoszupresszív stratégiát jelent. Az allergiás betegségek molekuláris hátterét vizsgálva a C3a szerkezetéből kiindulva olyan konformációsan gátolt peptidmimetikumokat állítottunk elő, amelyek megakadályozhatják a patológiás folyamatokat. Új szintézis módszereket dolgoztunk ki peptid nukleinsavak előállítására. | Most of the neurodegenerative diseases possess a common mechanism: a polypeptide or protein forms by misfolding water insoluble aggregates that precipitate extra- or intracellularly. These toxic aggregates hinder interneuronal connections and destroy neurons. Our laboratory proved in model experiments of Alzheimer's disease (AD) that the two main forms (oligomeric and fibrillar) of the toxic polypeptide beta-amyloid 1-42 affect different membrane receptors. Heavy metal ions, eng. Zn2+, may play key role in formation of toxic aggregates, therefore Zn-chelator drugs (e.g. ACE-inhibitors) could be used for the prevention of AD. Another group of compounds (peptides and peptidomimetics) protects neurons by covering the surface of Abeta-aggregates so preventing the interaction with membrane receptors (patent application). Novel peptide vector molecules (penetratin derivatives) were synthesized and studied, their mechanism of action was proven (patent application). Studying a human beta-galactoside binding lectin (galectin 1) it was proven, that the compound very effectively prevent inflammation and autoimmun processes providing a new strategy for immunosupression. The molecular background of allergic diseases was studied. Starting from the structure of the complement protein C3a, conformationally restricted peptidomimetics were synthesized that may prevent the pathological processes. Novel synthetic methods were introduced for the preparation of peptide nucleic acids

Short analogs and mimetics of human urocortin 3 display antidepressant effects in vivo

Peptide analogs of urocortin 3[36-38] (Ucn 3[36-38]), obtained with deletion or replacement of amino acids of the original human urocortin 3 sequence, were designed, synthesized, and tested in vivo for treatment of depression. Based on the results of the biol. tests of the peptide analogs, several new peptidomimetics of the above short analogs of urocortin 3, including urea- and azapeptides, were also designed and synthesized and found to preserve the antidepressant-like effect of the 38 amino acid long original neuropeptide. The mol. modifications of urocortin 3[36-38] led to an improved understanding of the relationship between mol. structure and biol. activity of this peptide, and the novel peptidomimetics could be further tested for possible clin. treatment of depression. [on SciFinder(R)

Antiamnesic properties of analogs and mimetics of the tripeptide human urocortin 3

Amnesia is a deficit in memory caused by brain damage, disease, or trauma. Until now, there are no successful medications on the drug market available to treat amnesia. Short analogs and mimetics of human urocortin 3 (Ucn 3) tripeptide were synthesized and tested for their action against amnesia induced by eletroconvulsion in mice. Among the 16 investigated derivs. of Ucn 3 tripeptide, eight compds. displayed antiamnesic effect. Our results proved that the configuration of chiral center of glutamine does not affect the antiamnesic properties. Alkyl amide or isoleucyl amide at the C-terminus may lead to antiamnesic compds. As concerned the N-terminus, acetyl, Boc, and alkyl ureido moieties were found among the active analogs, but the free amino function at the N-terminus usually led to an inactive derivs. These observations may lead to the design and synthesis of small peptidomimetics and amino acid derivs. as antiamnesic drug candidates, although the elucidation of the mechanism of the action requires further investigations. [on SciFinder(R)