A growing number of orphan G-protein-coupled receptors (GPCRs) have been reported to be activated by lipid ligands, such as lysophosphatidic acid, sphingosine 1-phosphate (S1P), and cannabinoids, for which there are already well established receptors. These new ligand claims are controversial due to either lack of independent confirmations or conflicting reports. We used the ␤-arrestin PathHunter TM assay system, a newly developed, generic GPCR assay format that measures ␤-arrestin binding to GPCRs, to evaluate lipid receptor and ligand pairing. This assay eliminates interference from endogenous receptors on the parental cells because it measures a signal that is specifically generated by the tagged receptor and is immediately downstream of receptor activation. We screened a large number of newly "deorphaned" receptors (GPR23, GPR92, GPR55, G2A, GPR18, GPR3, GPR6, GPR12, and GPR63) and control receptors against a collection of ϳ400 lipid molecules to try to identify the receptor ligand in an unbiased fashion. GPR92 was confirmed to be a lysophosphatidic acid receptor with weaker responses to farnesyl pyrophosphate and geranylgeranyl diphosphate. The putative cannabinoid receptor GPR55 responded strongly to AM251, rimonabant, and lysophosphatidylinositol but only very weakly to endocannabinoids. G2A receptor was confirmed to be an oxidized free fatty acid receptor. In addition, we discovered that 3,3-diindolylmethane, a dietary molecule from cruciferous vegetables, which has known anti-cancer properties, to be a CB 2 receptor partial agonist, with binding affinity around 1 M. The anti-inflammatory effect of 3,3-diindolylmethane in RAW264.7 cells was shown to be partially mediated by CB 2 .

Improved rationally designed lead drug structures against African trypanosomiasis, Chagas disease, and leishmaniasis were obtained against trypanothione reductase from Trypanosoma cruzi. Substituted-benzyl [3-(2-chloro-4a, 10a-dihydrophenothiazin-10-yl)propyl]dimethylammonium salts, synthesized by Menschutkin quaternization of the tertiary alkylamine omega-nitrogen atom of chlorpromazine, were linear, competitive inhibitors of recombinant trypanothione reductase from T. cruzi, with either trypanothione disulfide or N-benzyloxycarbonyl-L-cysteinylglycyl 3-dimethylaminopropylamide disulfide as substrate. The permanent positive charge on the distal nitrogen atom of the tricyclic side chain contribution to binding was estimated as >/=5.6 kcal.mol(-1) by comparison with the analogue with the cationic nitrogen atom of the quaternary replaced by an ether oxygen atom. A further major contribution to improving K(i) values and inhibition strength was the hydrophobic natures and structures of the N-benzyl substituents. The strongest inhibitor, the [3-(2-chloro-4a,10a-dihydrophenothiazin-10-yl)propyl](3, 4-dichlorobenzyl)dimethylammonium derivative (K(i) 0.12 microM), was approximately 2 orders of magnitude more inhibitory than the parent chlorpromazine. Several of these quaternary phenothiazines completely inhibited T. brucei parasite growth in vitro at <1 microM. Antiparasite activity was not solely determined by inhibition strength against trypanothione reductase, there being a strong contribution from hydrophobicity (for example, benzhydryl-quaternized chlorpromazime had ED(50) < 1 microM). Although active against Leishmania donovani, none of the analogues showed major improvement in this activity relative to chlorpromazine or other nonquaternized phenothiazines. The p-tert-butylbenzyl-quaternized analogue very strongly inhibited (ED(50) < 1 microM) growth of the amastigote stage of T. cruzi.

Given the role of trypanothione in the redox defenses of pathogenic trypanosomal and leishmanial parasites, in contrast to glutathione for their mammalian hosts, selective inhibitors of trypanothione reductase are potential drug leads against trypanosomiasis and leishmaniasis. In the present study, the rational drug design approach was used to discover tricyclic neuroleptic molecular frameworks as lead structures for the development of inhibitors, selective for trypanothione reductase over host glutathione reductase. From a homology-modeled structure for trypanothione reductase, replaced in the later stages of the study by the X-ray coordinates for the enzyme from Crithidia fasciculata, a series of inhibitors based on phenothiazine was designed. These were shown to be reversible inhibitors of trypanothione reductase from Trypanosoma cruzi, linearly competitive with trypanothione as substrate and noncompetitive with NADPH, consistent with ping-pong bi bi kinetics. Analogues, synthesized to define structure-activity relationships for the active site, included N-acylpromazines, 2-substituted phenothiazines, and trisubstituted promazines. Analysis of Ki and I50 data, on the basis of calculated log P and molar refractivity values, provided evidence of a specially favored fit of small 2-substituents (especially 2-chloro and 2-trifluoromethyl), with a remote hydrophobic patch on the enzyme accessible for larger, hydrophobic 2-substituents. There was also evidence of an additional hydrophobic enzymic region available to suitable N-substituents of the promazine nucleus. Ki data also indicated that the phenothiazine nucleus can adopt more than one inhibitory orientation in its binding site. Selected compounds were tested for in vitro activity against Trypanosoma brucei, T. cruzi, and Leishmania donovani, with selective activities in the micromolar range being determined for a number of them.

Lipid metabolism, inflammation, oxidative stress and endothelial function play important roles in the pathogenesis of cardiovascular disease (CVD), which may be affected by an imbalance in the n-6/n-3 polyunsaturated fatty acid (PUFA) ratio. This study aimed to investigate the effects of the n-6/n-3 PUFA ratio on these cardiovascular risk factors in rats fed a high-fat diet using plant oils as the main n-3 PUFA source. The 1:1 and 5:1 ratio groups had significantly decreased serum levels of total cholesterol, low-density lipoprotein cholesterol, and proinflammatory cytokines compared with the 20:1 group (p < 0.05). Additionally, the 20:1 group had significantly increased serum levels of E-Selectin, von Willebrand factor (vWF), and numerous markers of oxidative stress compared with the other groups (p < 0.05). The 1:1 group had a significantly decreased lipid peroxide level compared with the other groups (p < 0.05). Serum levels of malondialdehyde, reactive oxygen species and vWF tended to increase with n-6/n-3 PUFA ratios increasing from 5:1 to 20:1. We demonstrated that low n-6/n-3 PUFA ratio (1:1 and 5:1) had a beneficial effect on cardiovascular risk factors by enhancing favorable lipid profiles, having anti-inflammatory and anti-oxidative stress effects, and improving endothelial function. A high n-6/n-3 PUFA ratio (20:1) had adverse effects. Our results indicated that low n-6/n-3 PUFA ratios exerted beneficial cardiovascular effects, suggesting that plant oils could be used as a source of n-3 fatty acids to prevent CVD. They also suggested that we should be aware of possible adverse effects from excessive n-3 PUFA.

Fabrics are widely used in hospitals and many other settings for bedding, clothing, and face masks; however, microbial pathogens can survive on surfaces for a long time, leading to microbial transmission. Coatings of metallic particles on fabrics have been widely used to eradicate pathogens. However, current metal particle coating technologies encounter numerous issues such as nonuniformity, processing complexity, and poor adhesion. To overcome these issues, an easy‐to‐control and straightforward method is reported to coat a wide range of fabrics by using gallium liquid metal (LM) particles to facilitate the deposition of liquid metal copper alloy (LMCu) particles. Gallium particles coated on the fabric provide nucleation sites for forming LMCu particles at room temperature via galvanic replacement of Cu2+ ions. The LM helps promote strong adhesion of the particles to the fabric. The presence of the LMCu particles can eradicate over 99% of pathogens (including bacteria, fungi, and viruses) within 5 min, which is significantly more effective than control samples coated with only Cu. The coating remains effective over multiple usages and against contaminated droplets and aerosols, such as those encountered in facemasks. This facile coating method is promising for generating robust antibacterial, antifungal, and antiviral fabrics and surfaces.

A series of heterocycle-containing oxindoles was synthesized and their HIV antiviral activities were assessed. Some of these analogs exhibited potent inhibitory activities against both wild-type virus and a number of drug-resistant mutant viruses. In addition, oxindole 9z also showed promising pharmacokinetics.

No abstract

Trypanothione reductase, the enzyme which in trypanosomal and leishmanial parasites catalyses the reduction of trypanothione disulphide to the redox-protective dithiol and has been identified as a potential target for rational antiparasite drug design, has been found to be strongly inhibited by tricyclic compounds containing the saturated dibenzazepine (imipramine) nucleus, with Ki values in the low micromolar range. This drug lead structure was designed by molecular graphics analysis of a three-dimensional homology model, focussing on the active-site. Inhibition studies were carried out to determine the effect of inhibitor structure on the inhibitory strength towards recombinant trypanothione reductase from Trypanosoma cruzi. Hansch analysis showed that inhibitory strength depended on terms in pi, pi 2 and sigma m indicating dependence on both lipophilicity and inductive effect for ring-substituted analogues of imipramine. The side-chain omega-aminoalkyl chain had to be longer than 2-carbon units for inhibition. The effect on inhibition strength of the substituent at the omega-amino position on the side-chain of the central ring nitrogen atom depended markedly on the detailed substitution pattern of the rest of the molecule. This provides kinetic evidence studies of multiple binding modes within a single, blanket binding site for the inhibitor with the tricyclic ring system in the general region of the hydrophobic pocket lined by Trp21, Tyr110, Met113 and Phe114. This aspect of the structural sensitivity of the precise active-site triangulation adopted by the inhibitor is probably a function of the use of hydrophobic interactions of low directional specificity in this pocket combined with an electrostatic anchoring by the omega-N+ HMe2 function of the inhibitor, presumably with a glutamate side-chain, such as Glu-18, Glu-466' and/or Glu-467'.