Stabilization of the open conformation οf insulin-regulated aminopeptidase by a novel substrate-selective small-molecule inhibitor.

Insulin-regulated aminopeptidase (IRAP) is an enzyme with important biological functions and the target of drug-discovery efforts. We combined in silico screening with a medicinal chemistry optimization campaign to discover a nanomolar inhibitor of IRAP based on a pyrazolylpyrimidine scaffold. This compound displays an excellent selectivity profile versus homologous aminopeptidases, and kinetic analysis suggests it utilizes an uncompetitive mechanism of action when inhibiting the cleavage of a typical dipeptidic substrate.

A Novel MAO-B/SSAO Inhibitor Improves Multiple Aspects of Dystrophic Phenotype in Mice.

Duchenne muscular dystrophy (DMD) is one of the most frequent and severe childhood muscle diseases. Its pathophysiology is multifaceted and still incompletely understood, but we and others have previously shown that oxidative stress plays an important role. In particular, we have demonstrated that inhibition of mitochondrial monoamine oxidases could improve some functional and biohumoral markers of the pathology.

Combining monoamine oxidase B and semicarbazide-sensitive amine oxidase enzyme inhibition to address inflammatory disease.

The discovery of a dual MAO-B/SSAO inhibitor PXS-5131 is reported. The compound offers a compact and rigid three-dimensional structure with superior selectivity over MAO-A. Potency and selectivity are linked to both the double bond geometry and stereochemistry of the allylamine moiety, highlighting the importance of optimal set up of these features in the class of amine oxidase inhibitors.

Identification and Optimization of Mechanism-Based Fluoroallylamine Inhibitors of Lysyl Oxidase-like 2/3.

Lysyl oxidase-like 2 (LOXL2) is a secreted enzyme that catalyzes the formation of cross-links in extracellular matrix proteins, namely, collagen and elastin, and is indicated in fibrotic diseases. Herein, we report the identification and subsequent optimization of a series of indole-based fluoroallylamine inhibitors of LOXL2. The result of this medicinal chemistry campaign is (), a potent, irreversible inhibitor that is >300-fold selective for LOXL2 over LOX.

The lysyl oxidase like 2/3 enzymatic inhibitor, PXS-5153A, reduces crosslinks and ameliorates fibrosis.

Fibrosis is characterized by the excessive deposition of extracellular matrix and crosslinked proteins, in particular collagen and elastin, leading to tissue stiffening and disrupted organ function. Lysyl oxidases are key players during this process, as they initiate collagen crosslinking through the oxidation of the ε-amino group of lysine or hydroxylysine on collagen side-chains, which subsequently dimerize to form immature, or trimerize to form mature, collagen crosslinks. The role of LOXL2 in fibrosis and cancer is well documented, however the specific enzymatic function of LOXL2 and LOXL3 during disease is less clear.

Synthetic Studies on the Natural Product Myrsinoic Acid F Reveal Biologically Active Analogues.

The synthesis of the structure, 1, assigned to the anti-inflammatory natural product myrsinoic acid F is reported together with a means for preparing its Z-isomer 21. While neither of these compounds corresponds to the natural product, both of them are anti-inflammatory agents (as determined using a mouse ear edema assay) with congener 1 being notably more potent than the widely prescribed NSAID indometacin.

Inhibition of semicarbazide-sensitive amine oxidase/vascular adhesion protein-1 reduces lipopolysaccharide-induced neuroinflammation.

Background And Purpose: Neuroinflammation is initiated by a variety of stimuli including infections, sepsis, neurodegenerative diseases or traumatic brain injury and, if not adequately controlled, can lead to various degrees of neuronal damage and behavioural impairment. A critical event in the initial steps of inflammation is neutrophil extravasation. Semicarbazide-sensitive amine oxidase (SSAO, also known as vascular adhesion protein 1 or VAP-1) regulates neutrophil adhesion and extravasation.

Pre-clinical evaluation of small molecule LOXL2 inhibitors in breast cancer.

Lysyl Oxidase-like 2 (LOXL2), a member of the lysyl oxidase family of amine oxidases is known to be important in normal tissue development and homeostasis, as well as the onset and progression of solid tumors. Here we tested the anti-tumor properties of two generations of novel small molecule LOXL2 inhibitor in the MDA-MB-231 human model of breast cancer. We confirmed a functional role for LOXL2 activity in the progression of primary breast cancer.

Effects of an anti-inflammatory VAP-1/SSAO inhibitor, PXS-4728A, on pulmonary neutrophil migration.

Background And Purpose: The persistent influx of neutrophils into the lung and subsequent tissue damage are characteristics of COPD, cystic fibrosis and acute lung inflammation. VAP-1/SSAO is an endothelial bound adhesion molecule with amine oxidase activity that is reported to be involved in neutrophil egress from the microvasculature during inflammation. This study explored the role of VAP-1/SSAO in neutrophilic lung mediated diseases and examined the therapeutic potential of the selective inhibitor PXS-4728A.

PXS-4681A, a potent and selective mechanism-based inhibitor of SSAO/VAP-1 with anti-inflammatory effects in vivo.

Semicarbazide-sensitive amine oxidase (SSAO), also known as vascular adhesion protein-1 (VAP-1), is a member of the copper-dependent amine oxidase family that is associated with various forms of inflammation and fibrosis. To investigate the therapeutic potential of SSAO/VAP-1 inhibition, potent and selective inhibitors with drug-like properties are required. PXS-4681A [(Z)-4-(2-(aminomethyl)-3-fluoroallyloxy)benzenesulfonamide hydrochloride] is a mechanism-based inhibitor of enzyme function with a pharmacokinetic and pharmacodynamic profile that ensures complete, long-lasting inhibition of the enzyme after a single low dose in vivo.

The discovery and development of selective 3-fluoro-4-aryloxyallylamine inhibitors of the amine oxidase activity of semicarbazide-sensitive amine oxidase/vascular adhesion protein-1 (SSAO/VAP-1).

A new class of 3-fluoroallyl amine-based SSAO/VAP-1 inhibitors is reported. These compounds have excellent selectivity over diamine oxidase, MAO-A and MAO-B. Synthesis and SAR studies leading to compound 28 (PXS-4159A) are reported.

Protein-protein coupling and its application to functional red cell substitutes.

The need for an alternative to red cells for oxygen transport in transfusions has led to the creation of hemoglobin-based oxygen carriers, materials produced by chemical modification or genetic engineering of human or bovine hemoglobin. Modifications of the native proteins are necessitated by the spontaneous dissociation of the functional hemoglobin tetramers (alpha(2)beta(2)) into non-functional alphabeta dimers. Based on clinical observations of hypertension resulting from some of these materials, it was proposed that the stabilized tetramers are sufficiently small to extravasate through blood vessels and scavenge nitric oxide, depleting the endothelium of the signal for smooth muscle relaxation.

Hemoglobin bis-tetramers via cooperative azide-alkyne coupling.

Cross-linked hemoglobin-azides react with a bis-alkyne to form a bis-tetramer through sequential "click" reactions where the second step is promoted by the first.

Tandem oxidation processes using manganese dioxide: discovery, applications, and current studies.

"One-pot" processes in which alcohol oxidations are combined with further elaboration of the carbonyl intermediate are reviewed. Sequential processes are briefly discussed, but most attention is centered on tandem processes; that is, oxidations carried out in the presence of a nucleophilic trapping agent, rather than those in which the trapping agent is added after the oxidation is complete. As part of this Account, a comprehensive review of the discovery of tandem oxidation processes (TOP) will be given together with applications in alkene-forming reactions, cyclopropanations, and imine, oxime, amine, and heterocycle formation.

Unexpected Z-stereoselectivity in the Ramberg-Bäcklund reaction of diarylsulfones leading to cis-stilbenes: the effect of aryl substituents and application in the synthesis of the integrastatin nucleus.

With certain substituent patterns, benzyl benzyl sulfone systems have been found to give unexpectedly high Z-stereoselectivity (up to E:Z = 1:16) in the Meyers variant of the Ramberg-Bäcklund reaction. A range of sulfones, bearing various aryl substituents, were explored to rationalize this unprecedented selectivity for Z-stilbene systems. This high level of double bond stereocontrol has also been utilized in the synthesis of integrastatin nucleus, the core of two highly bioactive anti-HIV compounds.

An empirical study of the effect of the variables in a flash vacuum pyrolysis (FVP) experiment.

The effect of the variation of the experimental parameters on the conversion of precursor to products in a typical flash vacuum pyrolysis (FVP) experiment was investigated empirically. Temperature-conversion plots can be used to optimise FVP conditions and their mechanistic significance is exemplified. At a given temperature, the conversion can be increased by an increase in the background pressure, or by packing a section of the furnace tube with inert material (particularly when placed at the trap end of the furnace tube) or by employing a catalyst.

Synthesis of the integrastatin nucleus using the Ramberg-Bäcklund reaction.

[reaction: see text] The first synthesis of the tetracyclic nucleus of the Integrastatins, natural products that have been shown to selectively inhibit HIV-1 integrase, is reported. Key steps of this synthesis involve a novel cis-selective Ramberg-Bäcklund reaction and an unusual Lewis acid-promoted cyclization step.