Exploring Tau Fibril-Disaggregating and Antioxidating Molecules Binding to Membrane-Bound Amyloid Oligomers Using Machine Learning-Enhanced Docking and Molecular Dynamics.

Intracellular tau fibrils are sources of neurotoxicity and oxidative stress in Alzheimer's. Current drug discovery efforts have focused on molecules with tau fibril disaggregation and antioxidation functions. However, recent studies suggest that membrane-bound tau-containing oligomers (mTCOs), smaller and less ordered than tau fibrils, are neurotoxic in the early stage of Alzheimer's. Whether tau fibril-targeting molecules are effective against mTCOs is unknown. The binding of epigallocatechin-3-gallate (EGCG), CNS-11, and BHT-CNS-11 to in silico mTCOs and experimental tau fibrils was investigated using machine learning-enhanced docking and molecular dynamics simulations. EGCG and CNS-11 have tau fibril disaggregation functions, while the proposed BHT-CNS-11 has potential tau fibril disaggregation and antioxidation functions like EGCG. Our results suggest that the three molecules studied may also bind to mTCOs. The predicted binding probability of EGCG to mTCOs increases with the protein aggregate size. In contrast, the predicted probability of CNS-11 and BHT-CNS-11 binding to the dimeric mTCOs is higher than binding to the tetrameric mTCOs for the homo tau but not for the hetero tau-amylin oligomers. Our results also support the idea that anionic lipids may promote the binding of molecules to mTCOs. We conclude that tau fibril-disaggregating and antioxidating molecules may bind to mTCOs, and that mTCOs may also be useful targets for Alzheimer's drug design.

Phenylacetyl-/Trolox- Amides: Synthesis, Sigma-1, HDAC-6, and Antioxidant Activities.

In search of novel multi-mechanistic approaches for treating Alzheimer's disease (AD), we have embarked on synthesizing single small molecules for probing contributory roles of the following combined disease targets: sigma-1 (σ-1), class IIb histone deacetylase-6 (HDAC-6), and oxidative stress (OS). Herein, we report the synthesis and partial evaluation of 20 amides (i.e., phenylacetic and Trolox or 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid derivatives). Target compounds were conveniently synthesized via amidation by either directly reacting acyl chlorides with amines or condensing acids with amines in the presence of coupling agents 1-[bis(dimethylamino)methylene]-1H-1,2,3-triazolo [4,5-b] pyridinium 3-oxide hexafluorophosphate (HATU) or 1,1'-carbonyldiimidazole (CDI). Overall, this project afforded compound 8 as a promising lead with σ-1 affinity (Ki = 2.1 µM), HDAC-6 (IC50 = 17 nM), and antioxidant (1.92 Trolox antioxidant equivalents or TEs) activities for optimization in ensuing structure-activity relationship (SAR) studies.

Exploring the Role of Anionic Lipid Nanodomains in the Membrane Disruption and Protein Folding of Human Islet Amyloid Polypeptide Oligomers on Lipid Membrane Surfaces Using Multiscale Molecular Dynamics Simulations.

The aggregation of human Islet Amyloid Polypeptide (hIAPP) on cell membranes is linked to amyloid diseases. However, the physio-chemical mechanisms of how these hIAPP aggregates trigger membrane damage are unclear. Using coarse-grained and all-atom molecular dynamics simulations, we investigated the role of lipid nanodomains in the presence or absence of anionic lipids, phosphatidylserine (PS), and a ganglioside (GM1), in the membrane disruption and protein folding behaviors of hIAPP aggregates on phase-separated raft membranes. Our raft membranes contain liquid-ordered (Lo), liquid-disordered (Ld), mixed Lo/Ld (Lod), PS-cluster, and GM1-cluster nanosized domains. We observed that hIAPP aggregates bound to the Lod domain in the absence of anionic lipids, but also to the GM1-cluster- and PS-cluster-containing domains, with stronger affinity in the presence of anionic lipids. We discovered that L16 and I26 are the lipid anchoring residues of hIAPP binding to the Lod and PS-cluster domains. Finally, significant lipid acyl chain order disruption in the annular lipid shells surrounding the membrane-bound hIAPP aggregates and protein folding, particularly beta-sheet formation, in larger protein aggregates were evident. We propose that the interactions of hIAPP and both non-anionic and anionic lipid nanodomains represent key molecular events of membrane damage associated with the pathogenesis of amyloid diseases.

Design and Synthesis of New Acyl Urea Analogs as Potential σ1R Ligands.

In search of synthetically accessible open-ring analogs of PD144418 or 5-(1-propyl-1,2,5,6-tetrahydropyridin-3-yl)-3-(p-tolyl)isoxazole, a highly potent sigma-1 receptor (σ1R) ligand, we herein report the design and synthesis of sixteen arylated acyl urea derivatives. Design aspects included modeling the target compounds for drug-likeness, docking at σ1R crystal structure 5HK1, and contrasting the lower energy molecular conformers with that of the receptor-embedded PD144418-a molecule we opined that our compounds could mimic pharmacologically. Synthesis of our acyl urea target compounds was achieved in two facile steps which involved first generating the N-(phenoxycarbonyl) benzamide intermediate and then coupling it with the appropriate amines weakly to strongly nucleophilic amines. Two potential leads (compounds 10 and 12, with respective in vitro σ1R binding affinities of 2.18 and 9.54 µM) emerged from this series. These leads will undergo further structure optimization with the ultimate goal of developing novel σ1R ligands for testing in neurodegeneration models of Alzheimer's disease (AD).

The "first-generation effect" on perceptions and academic performance of pharmacy students.

INTRODUCTION: The "first-generation effect" refers to familial educational attainment's role in first-generation student academic success. It often implies low academic achievements at associate and bachelor degree levels. Would this be true at the doctor of pharmacy (PharmD) level? This study assessed perceptions and first-professional (P1) year student academic performance of first-generation vs. non-first-generation PharmD cohorts at the Feik School of Pharmacy. METHODS: Perceptions (academic and personal support) were assessed via a 49-question survey at the start of the second- and third-professional years. Academic performance was assessed via measures of academic success (course grades, grade point average, supplemental instruction enrollments, and academic infractions) in P1 year. Statistical t-tests and F-tests were used to analyze differences in perceptions and academic performance for the two cohorts. RESULTS: From 132 eligible students, 128 completed the survey (97% response rate) and 58 (45%) were first-generation students. First-generation students had a lower perception of their academic success, and they perceived finances as one of their greatest barriers (86% vs. 64%). Fifteen P1 courses were reviewed for academic performance, and first generations had lower final course grades in only two courses (Anatomy and Physiology 1; Medical Microbiology and Immunology). For measures of academic success, no significant differences were noted. CONCLUSIONS: Overall, this study suggested that first-generation status may not be a hindrance to academic performance at the PharmD level, but that financial perceptions and a lower self-perception of academic success seem to be major barriers for first-generation PharmD students.

A review of phenformin, metformin, and imeglimin.

Diabetes mellitus is a serious metabolic disorder affecting millions of people worldwide. Phenformin and metformin are biguanide antidiabetic agents that are conveniently synthesized in a single-step chemical reaction. Phenformin was once used to lower blood glucose levels, but later withdrawn from the market in several countries because it was frequently associated with lactic acidosis. Metformin is still a widely prescribed medication for the treatment of type 2 diabetes despite the introduction of several newer antidiabetic agents. Metformin is administered orally and has desirable pharmacokinetics. Incidence of metformin-induced lactic acidosis is serious but very rare. Imeglimin, a novel molecule being investigated by Poxel and Sumitomo Dainippon Pharma in Japan, is currently in clinical trials for the treatment of type 2 diabetes. Unlike metformin, imeglimin is a cyclic molecule containing a triazine ring. However, like metformin, imeglimin is also a basic small molecule. Imeglimin is synthesized from metformin as a precursor via a single step chemical reaction. Recent mechanism of action studies suggests that imeglimin improves mitochondria function, when given in combination with metformin it helps achieve better glycemic control in patients with type 2 diabetes. We herein describe and compare the current status, synthesis, physicochemical properties, pharmacokinetic parameters, mechanism of action, and preclinical/clinical studies of metformin and imeglimin.

4,5-Dimethoxy-2-nitrobenzohydrazides and 1-(1-Benzylpiperidin-4-yl)ethan-1-ones as Potential Antioxidant/Cholinergic Endowed Small Molecule Leads.

The objective of this research is to generate leads for developing our ultimate poly-active molecules with utility in central nervous system (CNS) diseases. Indeed, poly-active molecules capable of mitigating brain free radical damage while enhancing acetylcholine signaling (via cholinesterase inhibition) are still being sought for combating Alzheimer's disease (AD). We differentiate "poly-active" agents from "multi-target" ones by defining them as single molecular entities designed to target only specific contributory synergistic pharmacologies in a disease. For instance, in AD, free radicals either initiate or act in synergy with other pharmacologies, leading to disease worsening. For this preliminary report, a total of 14 (i.e., 4,5-dimethoxy-2-nitrobenzohydrazide plus 1-(1-benzylpiperidin-4-yl)ethan-1-one) derivatives were synthesized and screened, in silico and in vitro, for their ability to scavenge free radicals and inhibit acetylcholinesterase (AChE)/butyrylcholinesterase (BuChE) enzymes. Overall, six derivatives (4a, 4d, 4e, 4f, 4g, 9b) exhibited potent (>30%) antioxidant properties in the oxygen radical absorbance capacity (ORAC) assay. The antioxidant values were either comparable or more potent than the comparator molecules (ascorbic acid, resveratrol, and trolox). Only three compounds (4d, 9a, 9c) yielded modest AChE/BuChE inhibitions (>10%). Please note that a SciFinder substance data base search confirmed that most of the compounds reported herein are new, except 9a and 9c which are also commercially available.

Alzheimer's Drug Discovery Maze: A Snap View of the Past Decade's Diverse Pharmacological Targets for the Disorder.

The discovery of disease modifying anti-Alzheimer's molecules continues to be dared by: disease target multiplicity, downstream neurodegenerative biochemistry complexities, and genotype implications. A confluence of the above ingredients has contributed to a pipeline of creative molecules that regrettably underperform in clinical trials. Thus far, only five palliative pharmacotherapeutic agents, that is, four acetylcholine potentiating agents and an N-methyl-D-aspartate (NMDA) antagonist are clinically available. In this review we collectively describe the currently suggested targetable pathways for designing anti-Alzheimer's agents (palliative and/or disease modifying). We are prompted to contribute in this manner out of a desire to simplify and consolidate, to a certain extent, the divergent target literature on Alzheimer's drug discovery. We herein provide a summary update and perspective on realized and potentially druggable pharmacological targets for this CNS disorder. This article covers mostly the 2005-2015 medicinal chemistry/pharmacological/biological literature space on the subject.

The medicinal chemistry of 5-HT6 receptor ligands with a focus on arylsulfonyltryptamine analogs.

Arylsulfonyl analogs of aminopyrimidines (e.g. Ro 04-6790; 2), aminopyridines (e.g. Ro 63-0563; 3), 1-phenylpiperazines (e.g. SB-271046; 4), and tryptamines (e.g. MS-245; 5) were described as the first examples of selective 5-HT(6) receptor antagonists only ten years ago. Today, hundreds of compounds of seemingly diverse structure have been reported. The early antagonists featured an arylsulfonyl group leading to the wide notspread assumption that an arylsulfonyl moiety might be critical for binding and antagonist action. With respect to the arylsulfonyltryptamines, it seems that neither the "arylsulfonyl" nor the "tryptamine" portion of these compounds is essential for binding or for antagonist action, and some such derivatives even display agonist action. The present review describes many of the currently available 5-HT(6) receptor ligands and, unlike prior reviews, provides a narrative of the thinking (where possible) that led to their design, synthesis, and evaluation. The arylsulfonyltryptamines are also used as the structural basis of attempts to relate various structure-types to one another to afford a better understanding of the overall structural requirements for 5-HT(6) receptor binding.

Synthesis and evaluation of ligands for D2-like receptors: the role of common pharmacophoric groups.

Arylcycloalkylamines, such as phenyl piperidines and piperazines and their arylalkyl substituents, constitute pharmacophoric groups exemplified in several antipsychotic agents. A review of previous reports indicates that arylalkyl substituents can improve the potency and selectivity of the binding affinity at D(2)-like receptors. In this paper, we explored the contributions of two key pharmacophoric groups, that is, 4'-fluorobutyrophenones and 3-methyl-7-azaindoles, to the potency and selectivity of synthesized agents at D(2)-like receptors. Preliminary observation of binding affinities indicates that there is little predictability of specific effects of the arylalkyl moieties but the composite structure is responsible for selectivity and potency at these receptors.

Binding of sulfonyl-containing arylalkylamines at human 5-HT6 serotonin receptors.

Various sulfonyl-containing compounds (e.g. sulfonamides, sulfones) bind at human 5-HT6 serotonin receptors, but it has been difficult relating the binding mode(s) of such agents to one another, even though many possess a common SO2 moiety, to identify a common pharmacophore model(s). On the basis of the hypothesis that an ergoline-type conformation might be important for the binding of some sulfonamide-containing arylalkylamines, we prepared for examination at h5-HT6 receptors a series of compounds, including phenylethylamines 6, pyrroloethylamine 7, and phenylpiperazines 9. The results (with Ki values ranging from about 1 nM to >1000 nM) suggest that many of these agents likely bind in a related fashion, and structure-affinity studies indicate that the benzenesulfonamide portion of the phenylethylamine and phenylpiperazine analogues can be "reversed", abbreviated to a sulfone, and moved to an adjacent position with relatively little impact on affinity. Although a benzenesulfonamide (or related arylsulfonamide) group might be common to various 5-HT6 ligands, there appears to be some latitude with regard to the specific constitution and location of the sulfonamide moiety even within the same arylalkylamine structural framework. A pharmacophore model is presented to account for some of the current findings.

Haloperidol: towards further understanding of the structural contributions of its pharmacophoric elements at D2-like receptors.

An attempt to understand the pharmacophore-relevant position of the alcoholic moiety in haloperidol and the contributions of other pharmacophoric elements led to the re-synthesis of its tropane analogue (compound 2). An analysis of the binding data suggests that haloperidol binds to the DA receptors with the OH group in the axial position and the OH group, while not essential for binding, enhances binding especially at the D2 receptor. It also became clear that shortening the butyrophenone chain not only reduces binding affinity at the DA receptors but eliminates subtype selectivity.

The acute EPS of haloperidol may be unrelated to its metabolic transformation to BCPP+.

We have previously proposed that haloperidol's debilitating extrapyramidal symptoms (EPS) may be associated with its quaternary BCPP+ (an MPP+ like species) metabolite formed in vivo. However, recent work on D2 knock out mice suggests that haloperidol's EPS may be related to its potent D2 binding (K(i)=0.9 nM). In this study, we explore this question by synthesizing and testing an analogue (DS-27) that binds to D2 receptors with higher affinity than haloperidol, but cannot form quaternary metabolites. This study suggests that D2 affinity may be the primary underlying mechanism for acute catalepsy induction by haloperidol.