Refined homology model of monoacylglycerol lipase: toward a selective inhibitor

Monoacylglycerol lipase (MGL) is primarily responsible for the hydrolysis of 2-arachidonoylglycerol (2-AG), an endocannabinoid with full agonist activity at both cannabinoid receptors. Increased tissue 2-AG levels consequent to MGL inhibition are considered therapeutic against pain, inflammation, and neurodegenerative disorders. However, the lack of MGL structural information has hindered the development of MGL-selective inhibitors. Here, we detail a fully refined homology model of MGL which preferentially identifies MGL inhibitors over druglike noninhibitors. We include for the first time insight into the active-site geometry and potential hydrogen-bonding interactions along with molecular dynamics simulations describing the opening and closing of the MGL helical-domain lid. Docked poses of both the natural substrate and known inhibitors are detailed. A comparison of the MGL active-site to that of the other principal endocannabinoid metabolizing enzyme, fatty acid amide hydrolase, demonstrates key differences which provide crucial insight toward the design of selective MGL inhibitors as potential drugs.     

hCB2 ligand-interaction landscape: cysteine residues critical to biarylpyrazole antagonist binding motif and receptor modulation

The human cannabinoid 2 GPCR (hCB2) is a prime therapeutic target. To define potential cysteine-related binding motifs critical to hCB2-ligand interaction, a library of hCB2 cysteine-substitution mutants and a novel, high-affinity biarylpyrazole hCB2 antagonist/inverse agonist (AM1336) functionalized to serve as a covalent affinity probe to target cysteine residues within (or in the microenvironment of) its hCB2 binding pocket were generated. The data provide direct experimental demonstration that both hCB2 TMH7 cysteines [i.e., C7.38(284) and C7.42(288)] are critical to optimal hCB2-AM1336 binding interaction and AM1336 pharmacological activity in a cell-based functional assay (cAMP formation). Elongating the AM1336 aliphatic side chain generated another novel?hCB2 inverse agonist that binds covalently and selectively to C7.42(288) only. Identification of specific cysteine residues critical to hCB2 ligand interaction and function informs the structure-based design of hCB2-targeted medicines.     

The use of symmetry in the search for canted ferromagnetism, its application to the molecular magnets Mn[N(CN)2]2 and Fe[N(CN)2]2

Canted ferromagnets present a important class of molecular magnets. In these materials the uncompensated magnetisation, created by the DzyaloshinskyMoriya interaction, has the particular property of being compatible with the symmetry of the underlying antiferromagnetic Hamiltonian. If the ordering transition is continuous, Landau theory and simple symmetry arguments about the crystal structure can be used to determine whether such parasitic ferromagnetism is possible, and therefore to aid the systematic search for new molecular ferromagnets.     

Finite volume adaptive solutions using SIMPLE as smoother

This paper describes a new multilevel procedure that can solve the discrete Navier–Stokes system arising from finite volume discretizations on composite grids, which may consist of more than one level. SIMPLE is used and tested as the smoother, but the multilevel procedure is such that it does not exclude the use of other smoothers. Local refinement is guided by a criterion based on an estimate of the truncation error. The numerical experiments presented test not only the behaviour of the multilevel algebraic solver, but also the efficiency of local refinement based on this particular criterion. Copyright © 2006 John Wiley & Sons, Ltd.     

A Spectro-Microscopic Approach for Thin Film Analysis: Grain Boundaries in mc-Si and Sn/SnO2 Nano Particles

 Synchrotron radiation based spectro-microscopy is shown to be an exciting tool for elemental analysis in the field of heterogeneous interfaces, thin films, and device technology. Results are reported, taken with a spectrometer that enables the combination of a photoemission electron microscope (PEEM) with photoelectron spectroscopies (XPS, UPS) operated at a high brilliance undulator beam line at BESSY. The properties of mc-Si (multi crystalline silicon) are of interest because of their applications in low priced photovoltaic devices. An example of how to analyze the surface potentials of such surfaces without removing the native oxide is given. Tin nano-scale particles are shown to be the decisive factor affecting the corrosion prevention of passivated tinplate surfaces.     

Aspirin-triggered metabolites of EFAs

Aspirin triggers the biosynthesis of oxygenated metabolites from arachidonic, eicosapentaenoic, and docosahexaenoic (DHA) acids. In a preceding issue, Serhan et?al. (2011) describe a novel aspirin-triggered DHA pathway for the biosynthesis of a potent anti-inflammatory and proresolving molecule.     

KrF laser ablation of a polyethersulfone film: Effect of pulse duration on structure formation

Polyethersulfone (PES) films were processed with KrF laser irradiation of different pulse durations (τ). Scanning electron microscopy (SEM) and Raman spectroscopy were employed for the examination of the morphology and chemical composition of the irradiated surfaces, respectively. During ablation with 500 fs and 5 ps pulses, localized deformations (beads), micro-ripple and conical structures were observed on the surface depending on the irradiation fluence (F) and the number of pulses (N). In addition, the number density of the structures is affected by the irradiation parameters (τ, F, N). Furthermore, at longer pulse durations (τ = 30 ns), conical structures appear at lower laser fluence values, which are converted into columnar structures upon irradiation at higher fluences. The Raman spectra collected from the top of the structures following irradiation at different pulse durations revealed graphitization of the ns laser treated areas, in contrast to those processed with ultra-short laser pulses.     

Quantification of a single aggregate inner porosity and pore accessibility using hard X-ray phase-contrast nanotomography

The 3D structure of three individual aggregates composed of 165 nm polystyrene primary particles is revealed nondestructively by hard X-ray phase-contrast synchrotron nanotomography. Three-dimensional image analysis allows us for the first time to obtain the complex inner porosity of the entire aggregate. It is demonstrated that despite their rather compact structure, characterized by a fractal dimension equal to 2.7, the produced aggregates are still porous, with porosity increasing with its size. Generated pores have diameters from 100 nm to 3 μm and are almost completely interconnected.     

Magnetic iron oxide nanoclusters with tunable optical response

We have developed a modified synthetic protocol for the growth of monodispersed, superparamagnetic, flower-like colloidal nanoclusters (CNCs), which are consisted of smaller iron oxide nanocrystals with adjustable size. We show that their optical properties can be tuned by applying an external magnetic field. The latter controls the subtle balance of the CNCs’ mutual interactions (magnetic versus electrostatic) and drives their assembly in aqueous media. Spectrophotometric measurements reveal that a diffuse reflectance maximum, in the visible range, is related to the CNCs organization. As the strength of the external magnetic field increases, in the range 160–600 G, the spectral weight of this feature shifts towards the blue region of the spectrum. The induced photonic crystal-like response entails a remarkable magneto-optical behavior, closely associated with the size-dependent characteristics of the CNCs ensemble. Such materials pave the way for promising technological implementations in photonics.     

Interference with TGFβ1-Mediated Inflammation and Fibrosis Underlies Reno-Protective Effects of the CB1 Receptor Neutral Antagonists AM6545 and AM4113 in a Rat Model of Metabolic Syndrome

The role of cannabinoid receptors in nephropathy is gaining much attention. This study investigated the effects of two neutral CB1 receptor antagonists, AM6545 and AM4113, on nephropathy associated with metabolic syndrome (MetS). MetS was induced in rats by high-fructose high-salt feeding for 12 weeks. AM6545, the peripheral silent antagonist and AM4113, the central neutral antagonist were administered in the last 4 weeks. At the end of study, blood and urine samples were collected for biochemical analyses while the kidneys were excised for histopathological investigation and transforming growth factor beta 1 (TGFβ1) measurement. MetS was associated with deteriorated kidney function as indicated by the elevated proteinuria and albumin excretion rate. Both compounds equally inhibited the elevated proteinuria and albumin excretion rate while having no effect on creatinine clearance and blood pressure. In addition, AM6545 and AM4113 alleviated the observed swelling and inflammatory cells infiltration in different kidney structures. Moreover, AM6545 and AM4113 alleviated the observed histopathological alterations in kidney structure of MetS rats. MetS was associated with a ten-fold increase in urine uric acid while both compounds blocked this increase. Furthermore, AM6545 and AM4113 completely prevented the collagen deposition and the elevated expression of the TGFβ1 seen in MetS animals. In conclusion, AM6545 and AM4113, possess reno-protective effects by interfering with TGFβ1-mediated renal inflammation and fibrosis, via peripheral action.