Evaluation of Novel Guanidino-Containing Isonipecotamide Inhibitors of Blood Coagulation Factors against SARS-CoV-2 Virus Infection

Coagulation factor Xa (fXa) and thrombin (thr) are widely expressed in pulmonary tissues, where they may catalyze, together with the transmembrane serine protease 2 (TMPRSS2), the coronaviruses spike protein (SP) cleavage and activation, thus enhancing the SP binding to ACE2 and cell infection. In this study, we evaluate in vitro the ability of approved (i.e., dabigatran and rivaroxaban) and newly synthesized isonipecotamide-based reversible inhibitors of fXa/thr (cmpds 1–3) to hinder the SARS-CoV-2 infectivity of VERO cells. Nafamostat, which is a guanidine/amidine antithrombin and antiplasmin agent, disclosed as a covalent inhibitor of TMPRSS2, was also evaluated. While dabigatran and rivaroxaban at 100 μM concentration did not show any effect on SARS-CoV-2 infection, the virus preincubation with new guanidino-containing fXa-selective inhibitors 1 and 3 did decrease viral infectivity of VERO cells at subtoxic doses. When the cells were pre-incubated with 3, a reversible nanomolar inhibitor of fXa (Ki = 15 nM) showing the best in silico docking score toward TMPRSS2 (pdb 7MEQ), the SARS-CoV-2 infectivity was completely inhibited at 100 μM (p 3 on SARS-CoV-2 infection was evident (ca. 30%) at lower concentrations (3–50 μM). The covalent TMPRSS2 and the selective inhibitor nafamostat mesylate, although showing some effect (15–20% inhibition), did not achieve statistically significant activity against SARS-CoV-2 infection in the whole range of test concentrations (3–100 μM). These findings suggest that direct inhibitors of the main serine proteases of the blood coagulation cascade may have potential in SARS-CoV-2 drug discovery. Furthermore, they prove that basic amidino-containing fXa inhibitors with a higher docking score towards TMPRSS2 may be considered hits for optimizing novel small molecules protecting guest cells from SARS-CoV-2 infection

Assessing the Role of a Malonamide Linker in the Design of Potent Dual Inhibitors of Factor Xa and Cholinesterases

The rational discovery of new peptidomimetic inhibitors of the coagulation factor Xa (fXa) could help set more effective therapeutic options (to prevent atrial fibrillation). In this respect, we explored the conformational impact on the enzyme inhibition potency of the malonamide bridge, compared to the glycinamide one, as a linker connecting the P1 benzamidine anchoring moiety to the P4 aryl group of novel selective fXa inhibitors. We carried out structure-activity relationship (SAR) studies aimed at investigating Para- or meta-benzamidine as the P1 basic group as well as diversely decorated aryl moieties as P4 fragments. To this end, twenty-three malonamide derivatives were synthesized and tested as inhibitors of fXa and thrombin (thr); the molecular determinants behind potency and selectivity were also studied by employing molecular docking. The malonamide linker, compared to the glycinamide one, does significantly increase anti-fXa potency and selectivity. The meta-benzamidine (P1) derivatives bearing 2',4'-difluoro-biphenyl as the P4 moiety proved to be highly potent reversible fXa-selective inhibitors, achieving inhibition constants (K-i) in the low nanomolar range. The most active compounds were also tested against cholinesterase (ChE) isoforms (acetyl- or butyrylcholinesterase, AChE, and BChE), and some of them returned single-digit micromolar inhibition potency against AChE and/or BChE, both being drug targets for symptomatic treatment of mild-to-moderate Alzheimer's disease. Compounds 19h and 22b were selected as selective fXa inhibitors with potential as multimodal neuroprotective agents

Novel 6-alkyl-bridged 4-arylalkylpiperazin-1-yl derivatives of azepino[4,3-b]indol-1(2H)-one as potent BChE-selective inhibitors showing protective effects against neurodegenerative insults

Due to the putative role of butyrylcholinesterase (BChE) in regulation of acetylcholine levels and functions in the late stages of the Alzheimer's disease (AD), the potential of selective inhibitors (BChEIs) has been envisaged as an alternative to administration of acetylcholinesterase inhibitors (AChEIs). Starting from our recent findings, herein the synthesis and in vitro evaluation of cholinesterase (ChE) inhibition of a novel series of some twenty 3,4,5,6-tetrahydroazepino[4,3-b]indol-1(2H)-one derivatives, bearing at the indole nitrogen diverse alkyl-bridged 4-arylalkylpiperazin-1-yl chains, are reported. The length of the spacers, as well as the type of arylalkyl group affected the enzyme inhibition potency and BChE/AChE selectivity. Two compounds, namely 14c (IC50 = 163 nM) and 14d (IC50 = 65 nM), bearing at the nitrogen atom in position 6 a n-pentyl- or n-heptyl-bridged 4-phenethylpiperazin-1-yl chains, respectively, proved to be highly potent mixed-type inhibitors of both equine and human BChE isoforms, showing more than two order magnitude of selectivity over AChE. The study of binding kinetics through surface plasmon resonance (SPR) highlighted differences in their BChE residence times (8 and 47 s for 14c and 14d, respectively). Moreover, 14c and 14d proved to hit other mechanisms known to trigger neurodegeneration underlying AD and other CNS disorders. Unlike 14c, compound 14d proved also capable of inhibiting by more than 60% the in vitro self-induced aggregation of neurotoxic amyloid-β (Aβ) peptide at 100 μM concentration. On the other hand, 14c was slightly better than 14d in counteracting, at 1 and 10 μM concentration, glutamate excitotoxicity, due to over-excitation of NMDA receptors, and hydrogen peroxide-induced oxidative stress assessed in neuroblastoma cell line SH-SY5Y

Effects of treatment with etizolam 0.5 mg BID on cognitive performance: A 3-week, multicenter, randomized, double-blind, placebo-controlled, two-treatment, three-period, noninferiority crossover study in patients with anxiety disorder

Background: Etizolam is an anxiolytic drug with a pharmacologic profile similar to that of the classic benzodiazepines. Neurochemical research suggests that etizolam may have selectivity for the subpopulation of Y-aminobutyric acid type A receptors associated with anxiety (ie, α1, β2, γ2). This property, plus its characterization as a ligand with fewer of the adverse events typical of full agonists (impaired cognitive function, tolerance, and dependence), led to its selection for this study. Objectives: The primary aim of this study was to test for the noninferiority of etizolam 0.5 mg BID versus placebo in affecting cognitive function in patients with mild to moderate anxiety disorder of recent onset (<1 month). Anxiety measures and tolerability were also assessed. Methods: Patients between the ages of 18 and 65 years were eligible for enrollment. This doubleblind, placebo-controlled study was performed in 5 centers in Italy using a 2-treatment, 3-period crossover design. Patients were randomized to 3-week sequences of either etizolam-placebo-placebo or placebo-etizolam-etizolam. They were evaluated at 4 scheduled visits (screening and days 7, 14, and 21). Cognitive function was assessed using scores from the Wechsler Adult Intelligence Scale (WAIS) Digit Span test (total forward and backward scores and the time required to perform the test). Anxiety was measured using the Hamilton Anxiety Rating Scale (HAM-A) and the State-Trait Anxiety Inventory (STAI) for screening and to monitor adequacy of therapy. Blood pressure, heart rate, weight, and adverse events were also recorded. Results: A total of 77 white patients were enrolled (mean age, 33.3 years [range, 22-60 years]; 62.3% female; mean weight, 65.2 kg). With a power of 0.80, the difference between the effects of etizolam and placebo on WAIS Digit Span performance was not significant for total score (0.102 [90% CI, -0.130 to 0.335]) or time required for completion (0.029 second [90% CI, -0.574 to 0.632]). Anxiety, as measured using the HAM-A and STAI instruments, did not differ significantly between groups. No significant differences were found between etizolam 0.5 mg BID and placebo for cardiovascular events, weight changes, or adverse events. Mild or moderate somnolence was reported by 7 of 77 patients (9.1% [3 patients while receiving etizolam and 4 patients while receiving etizolam and placebo]). Conclusions: No significant differences between etizolam 0.5 mg BID and placebo were found for cognitive function or anxiety measures in these patients with anxiety. Etizolam was well tolerated. © 2009 Excerpta Medica Inc. All rights reserved

How a β‑d‑Glucoside Side Chain Enhances Binding Affinity to Thrombin of Inhibitors Bearing 2‑Chlorothiophene as P1 Moiety: Crystallography, Fragment Deconstruction Study, and Evaluation of Antithrombotic Properties

The β-d-glucose-containing compound <b>3</b>, bearing 2-chlorothiophene and 1-isopropylpiperidine moieties as binders of the S1 and S4 pockets, respectively, proved to be potent competitive inhibitor of factor Xa (fXa, <i>K</i>_i = 0.090 nM) and thrombin (fIIa, <i>K</i>_i = 100 nM). The potency of <b>3</b> increases, over the parent compound <b>1</b>, against fIIa (110-fold), much more than against fXa (7-fold). Experimental deconstruction of <b>3</b> into smaller fragments revealed a binding cooperativity of the P3/P4 and propylene-linked β-d-glucose fragments, stronger in fIIa (15.5 kJ·mol^–1) than in fXa (2.8 kJ·mol^–1). The crystal structure of human fIIa in complex with <b>3</b> revealed a binding mode including a strong H-bond network between the glucose O1′, O3′, and O5′ and two critical residues, namely R221a and K224, belonging to the Na⁺-binding site which may allosterically perturb the specificity sites. The potential of <b>3</b> as antithrombotic agent was supported by its ability to inhibit thrombin generation and to stimulate fibrinolysis at submicromolar concentration

Three-year results of ST-segment elevation myocardial infarction patients treated with a prespecified bioresorbable vascular scaffold implantation strategy: bVS STEMI STRATEGY-IT long-term

Three-year results of ST-segment elevation myocardial infarction patients treated with a prespecified bioresorbable vascular scaffold implantation strategy: bVS STEMI STRATEGY-IT long-ter

Synthesis and Biological Evaluation of Direct Thrombin Inhibitors Bearing 4‑(Piperidin-1-yl)pyridine at the P1 Position with Potent Anticoagulant Activity

The design and synthesis of a new class of nonpeptide direct thrombin inhibitors, built on the structure of 1-(pyridin-4-yl)­piperidine-4-carboxamide, are described. Starting from a strongly basic 1-amidinopiperidine derivative (<b>6</b>) showing poor thrombin (fIIa) and factor Xa (fXa) inhibition activities, anti-fIIa activity and artificial membrane permeability were considerably improved by optimizing the basic P1 and the X-substituted phenyl P4 binding moieties. Structure–activity relationship studies, usefully complemented with molecular modeling results, led us to identify compound <b>13b</b>, which showed excellent fIIa inhibition (<i>K</i>_i = 6 nM), weak anti-Xa activity (<i>K</i>_i = 5.64 μM), and remarkable selectivity over other serine proteases (e.g., trypsin). Compound <b>13b</b> showed in vitro anticoagulant activity in the low micromolar range and significant membrane permeability. In mice (ex vivo), <b>13b</b> demonstrated anticoagulant effects at 2 h after oral dosing (100 mg·kg^–1), with a significant 43% prolongation of the activated partial thromboplastin time (aPTT), over controls (<i>P</i> < 0.05)