Sinteza zaviralcev butirilholin esteraze s piridin-2-onskim in indolnim skeletom

Urbančič, Tajda (author), Gobec, Stanislav (mentor), Knez, Damijan (co-mentor)

Alzheimerjeva bolezen (AB) je progresivna in ireverzibilna nevrodegenerativna bolezen za katero so značilne kognitivne motnje ter številni nevropsihiatrični simptomi. Glavne morfološke spremembe, ki spremljajo AB, so nastanek zunajceličnih plakov, znotrajceličnih nevrofibrilarnih pentelj ter izguba nevronov, ki vsebujejo visoke koncentracije acetilholina in acetilholin esteraze (AChE), hkrati pa se povečata koncentracija in aktivnost butirilholin esteraze (BChE). Pomembno vlogo pri nevrovnetju, ki spremlja AB, ima tudi ubikvitin-proteasomski sistem. Selektivni zaviralci β1i podenote imunoproteasoma tako izboljšajo upad kognitivnih sposobnosti v mišjih modelih AB. V okviru magistrske naloge smo sintetizirali selektivne zaviralce človeške (h)BChE na osnovi serije zaviralcev z indolnim ogrodjem. Spreminjali smo dolžino distančnika med indolom in N-metilamidom na eni strani ter razdaljo med fenilom in N-metilamidom na drugi strani molekule. Terciarne amide smo sintetizirali z uporabo sklopitvenega reagenta CDI in ustreznih karboksilnih kislin ter aminov, nato pa smo amide z uporabo LiAlH4 reducirali do terciarnih aminov. Sintetiziranim spojinam smo z Ellmanovo metodo določili jakost zaviranja hBChE, preverili pa smo tudi njihovo selektivnost v primerjavi s strukturno podobnim encimom hAChE. Izmed 12 sintetiziranih derivatov indola je bil najmočnejši selektivni zaviralec hBChE terciarni amin 16 z IC50 = 8,36 ± 0,76 nM in faktorjem selektivnosti 3800 napram hAChE. Z analizo odnosa med strukturo in delovanjem smo potrdili, da z daljšanjem distančnika dosežemo 220-krat močnejše zaviranje hBChE, za zaviralno aktivnost pa je ugodna tudi prisotnost terciarnega amina. Zamenjava indola s piridin-2-onom, literaturno opisanim fragmentom selektivnih zaviralcev β1i podenote, je vodila v popolno izgubo zaviralne aktivnosti na hBChE kot tudi na AChE, spojine pa so bile neaktivne tudi na hAChE. Terciarnih aminov s piridin-2-onom zaradi sinteznih težav nismo uspeli pripraviti, glede na aktivnost aminskih indolnih analogov pa lahko na podlagi analize odnosa med strukturo in delovanjem sklepamo, da bi amini po vsej verjetnosti zavirali hBChE v nanomolarnem območju.

• Language: Slovenian
• Keywords: Alzheimerjeva bolezen, butirilholin esteraza, imunoproteasom, zaviralci
• Work type: Master's thesis/paper
• Organization: FFA - Faculty of Pharmacy
• Year: 2021
• PID: 20.500.12556/RUL-131348
• Publication date in RUL: 25.09.2021

Secondary language

• Language: English
• Title: Synthesis of butyrylcholinesterase inhibitors with pyridine-2-one and indole scaffold

Abstract

Alzheimer's disease (AD) is a progressive, irreversible neurodegenerative disorder manifested by cognitive impairment and neuropsychiatric symptoms. The main morphological changes that characterize AD are development of extracellular neuritic plaques and intracellular neurofibrillary tangles, loss of neurons with high acetylcholine and acetylcholinesterase (AChE) concentration, and increase in the concentration and activity of butyrylcholinesterase (BChE). The ubiquitin-proteasome pathway has a major role in neuroinflammation, which is a characteristic pathology of AD. Selective inhibitors of immunoproteasome β1i subunit showed improvement of cognitive impairment in mouse models of ADs. We synthesized selective hBChE inhibitors based on a series of indole analogues. The length of the linker connecting indole and N-methylamide on one side of the molecule and the linker between phenyl and N-methylamide on the other side were systematically varied. Tertiary amides were obtained with CDI-mediated coupling of corresponding carboxylic acids and amines, followed by the reduction using LiAlH4 to furnish tertiary amines. hBChE inhibitory potencies were determined using Ellman’s method and compared to inhibition of structurally related hAChE. Among 12 indoles synthesized, tertiary amine 16 was the most potent inhibitor of hBChE with IC50 of 8.36 ± 0.76 nM and selectivity factor of 3800 vs hAChE. Structure-activity relationships analyses revealed that the elongation of linkers lead to 220-fold increase in hBChE inhibitory potency and that tertiary amines improved hBChE inhibition. Pyridine-2-ones are described as selective inhibitors of immunoproteasome subunit β1i. Replacing indole with pyridine-2-one led to complete loss of hBChE and hAChE inhibitory activities. Difficulties in the synthetic procedures precluded generation of corresponding amines. Nonetheless, based on the structure-activity relationships established with the indole series, we can speculate that amines would inhibit hBChE in the nanomolecular range.

• Keywords: Alzheimer's disease, butyrylcholinesterase, immunoproteasome, inhibitors