Riparin II-type benzamides as novel antibiofilm agents against dermatophytes: chemical synthesis, in vitro, ex vivo and in silico evaluation.

BACKGROUND: The ability of dermatophytes to develop biofilms in host tissues confers physical and biochemical resistance to antifungal drugs. Therefore, research to find new compounds against dermatophyte biofilm is crucial. OBJECTIVES: To evaluate the antifungal activity of riparin II (RIP2), nor-riparin II (NOR2) and dinor-riparin II (DINOR2) against Trichophyton rubrum, Microsporum canis and Nannizzia gypsea strains. METHODS: Initially, we determined the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of benzamides. We evaluated the inhibitory effects on the development of dermatophyte biofilms using in vitro and ex vivo models. Finally, we built three-dimensional models of the sulphite pump Ssu1 to investigate the interactions with the benzamides by molecular docking. RESULTS: RIP2 showed a broad spectrum of activity against T. rubrum, M. canis and N. gypsea, whereas NOR2 and DINOR2 were more selective. Furthermore, the shortening of the carbon chain from RIP2 benzamide to NOR2 and DINOR2 homologs caused a decrease in the MIC values. The benzamides reduced biofilm production and viability in vitro (P < 0.05) at MIC. This result was similar ex vivo in human nail fragments tests, but NOR2 and DINOR2 showed significant results at 2xMIC (P < 0.05). We constructed a model of the Ssu1 protein for each dermatophyte with high similarity. Molecular docking showed that the benzamides obtained higher binding energy values than ciclopirox. CONCLUSIONS: Our study shows the antibiofilm potential for riparin II-type benzamides as new drugs targeting dermatophytes by inhibiting the Ssu1 protein.

New aspects characterizing non-obese NAFLD by the analysis of the intestinal flora and metabolites using a mouse model.

Non-alcoholic fatty liver disease (NAFLD) is a major public health problem due to the high incidence affecting approximately one-third of the world's population. NAFLD is usually linked to obesity and excessive weight. A subset of patients with NAFLD expresses normal or low body mass index; thus, the condition is called non-obese NAFLD or lean NAFLD. However, patients and healthcare professionals have little awareness and understanding of NAFLD in non-obese individuals. Furthermore, preclinical results from non-obese animal models with NAFLD are unclear. Gut microbiota and their metabolites in non-obese/lean-NAFLD patients differ from those in obese NAFLD patients. Therefore, we analyzed the biochemical indices, intestinal flora, and intestinal metabolites in a non-obese NAFLD mouse model established using a methionine-choline-deficient (MCD) diet. The significantly lean MCD mice had a remarkable fatty liver with lower serum triglyceride and free fatty acid levels, as well as higher alanine transaminase and aspartate transaminase levels than normal mice. 16S RNA sequencing of fecal DNA showed that the overall richness and diversity of the intestinal flora decreased in MCD mice, whereas the Firmicutes:Bacteroidota ratio was increased. g_Tuzzerella, s_Bifidobacterium pseudolongum, and s_Faecalibaculum rodentium were the predominant species in non-obese NAFLD mice. Fecal metabolomics using liquid chromatography-tandem mass spectrometry revealed the potential biomarkers for the prognosis and diagnosis of non-obese NAFLD, including high levels of tyramine glucuronide, 9,12,13-TriHOME, and pantetheine 4'-phosphate, and low levels of 3-carbamoyl-2-phenylpropionaldehyde, N-succinyl-L,L-2,6-diaminopimelate, 4-methyl-5-thiazoleethanol, homogentisic acid, and estriol. Our findings could be useful to identify and develop drugs to treat non-obese NAFLD and lean NAFLD. IMPORTANCE: Patients and healthcare professionals have little awareness and understanding of NAFLD in non-obese individuals. In fact, about 40% of people with NAFLD worldwide are non-obese, and nearly one-fifth are lean. Lean NAFLD unfortunately may be unnoticed for years and remains undetected until hepatic damage is advanced and the prognosis is compromised. This study focused on the lean NAFLD, screened therapeutic agents, and biomarkers for the prognosis and diagnosis using MCD-induced male C57BL/6J mice. The metabolites tyramine glucuronide, 9,12,13-TriHOME, and pantetheine 4'-phosphate, together with the predominant flora including g_Tuzzerella, s_Bifidobacterium pseudolongum, and s_Faecalibaculum rodentium, were specific in non-obese NAFLD mice and might be used as targets for non-obese NAFLD drug exploration. This study is particularly significant for non-obese NAFLDs that need to be more actively noticed and vigilant.

Chemical Synthesis and Biological Activities of Amaryllidaceae Alkaloid Norbelladine Derivatives and Precursors.

Amaryllidaceae alkaloids (AAs) are a structurally diverse family of alkaloids recognized for their many therapeutic properties, such as antiviral, anti-cholinesterase, and anticancer properties. Norbelladine and its derivatives, whose biological properties are poorly studied, are key intermediates required for the biosynthesis of all ~650 reported AAs. To gain insight into their therapeutic potential, we synthesized a series of O-methylated norbelladine-type alkaloids and evaluated their cytotoxic effects on two types of cancer cell lines, their antiviral effects against the dengue virus (DENV) and the human immunodeficiency virus 1 (HIV-1), and their anti-Alzheimer's disease (anti-cholinesterase and -prolyl oligopeptidase) properties. In monocytic leukemia cells, norcraugsodine was highly cytotoxic (CC50 = 27.0 µM), while norbelladine was the most cytotoxic to hepatocarcinoma cells (CC50 = 72.6 µM). HIV-1 infection was impaired only at cytotoxic concentrations of the compounds. The 3,4-dihydroxybenzaldehyde (selectivity index (SI) = 7.2), 3',4'-O-dimethylnorbelladine (SI = 4.8), 4'-O-methylnorbelladine (SI > 4.9), 3'-O-methylnorbelladine (SI > 4.5), and norcraugsodine (SI = 3.2) reduced the number of DENV-infected cells with EC50 values ranging from 24.1 to 44.9 µM. The O-methylation of norcraugsodine abolished its anti-DENV potential. Norbelladine and its O-methylated forms also displayed butyrylcholinesterase-inhibition properties (IC50 values ranging from 26.1 to 91.6 µM). Altogether, the results provided hints of the structure−activity relationship of norbelladine-type alkaloids, which is important knowledge for the development of new inhibitors of DENV and butyrylcholinesterase.

2-Hydroxymethyl-1-methyl-5-nitroimidazole, one siderophore inhibitor, occludes quorum sensing in Pseudomonas aeruginosa.

Siderophore is necessary for the survival of microorganisms and is interregulated with quorum sensing (QS) systems. It is related to growth, proliferation, virulence, and other bacterial social activities as a virulence factor. Thus, we speculated that the QS system could be occluded by inhibiting siderophore production. 2-Hydroxymethyl-1-methyl-5-nitroimidazole (HMMN), one siderophore inhibitor of Pseudomonas aeruginosa PAO1 (P. aeruginosa PAO1), was obtained by using the Chromeazurol S (CAS) method. We found that HMMN inhibited siderophore production and influenced the biological effects of QS regulation, including biofilm formation and pyocyanin production. HMMN (150 µg/ml) inhibited the siderophore production of P. aeruginosa PAO1 by 69.37%. In addition, HMMN could inhibit pyocyanin production and biofilm formation and erase the formed biofilm of P. aeruginosa PAO1. HMMN (150 µg/ml) inhibited the biofilm formation of P. aeruginosa PAO1 by 28.24%. The erasure rate of the formed biofilm reached 17.03%. Furthermore, HMMN (150 µg/ml) inhibited P. aeruginosa PAO1 pyocyanin production by 36.06%. Meanwhile, positive-control hordenine (500.0 µg/ml) reduced the biofilm formation and pyocyanin production of P. aeruginosa PAO1 by 14.42% and 34.35%, respectively. The erasure rate of hordenine to the formed biofilm is 11.05% at 500 µg/ml. Quantitative real-time polymerase chain reaction (qRT-PCR) showed that HMMN downregulates not only siderophore-related genes but also QS-related genes, as well as hordenine. These results suggest that a siderophore inhibitor could be used as a QS inhibitor to occlude the QS system and reduce virulence.

Multiple Direct Effects of the Dietary Protoalkaloid N-Methyltyramine in Human Adipocytes.

Dietary amines have been the subject of a novel interest in nutrition since the discovery of trace amine-associated receptors (TAARs), especially TAAR-1, which recognizes tyramine, phenethylamine, tryptamine, octopamine, N-methyltyramine (NMT), synephrine, amphetamine and related derivatives. Alongside the psychostimulant properties of TAAR-1 ligands, it is their ephedrine-like action on weight loss that drives their current consumption via dietary supplements advertised for 'fat-burning' properties. Among these trace amines, tyramine has recently been described, at high doses, to exhibit an antilipolytic action and activation of glucose transport in human adipocytes, i.e., effects that are facilitating lipid storage rather than mobilization. Because of its close structural similarity to tyramine, NMT actions on human adipocytes therefore must to be reevaluated. To this aim, we studied the lipolytic and antilipolytic properties of NMT together with its interplay with insulin stimulation of glucose transport along with amine oxidase activities in adipose cells obtained from women undergoing abdominal surgery. NMT activated 2-deoxyglucose uptake when incubated with freshly isolated adipocytes at 0.01-1 mM, reaching one-third of the maximal stimulation by insulin. However, when combined with insulin, NMT limited by half the action of the lipogenic hormone on glucose transport. The NMT-induced stimulation of hexose uptake was sensitive to inhibitors of monoamine oxidases (MAO) and of semicarbazide-sensitive amine oxidase (SSAO), as was the case for tyramine and benzylamine. All three amines inhibited isoprenaline-induced lipolysis to a greater extent than insulin, while they were poorly lipolytic on their own. All three amines-but not isoprenaline-interacted with MAO or SSAO. Due to these multiple effects on human adipocytes, NMT cannot be considered as a direct lipolytic agent, potentially able to improve lipid mobilization and fat oxidation in consumers of NMT-containing dietary supplements.

A New Saharan Strain of Streptomyces sp. GSB-11 Produces Maculosin and N-acetyltyramine Active Against Multidrug-Resistant Pathogenic Bacteria.

Multi-resistant bacterial pathogens are a major public health problem for treating nosocomial infections owing to their high resistance to antibiotics. The objective of this research was to characterize the bioactive molecules secreted by a novel moderately halophilic actinobacterium strain, designated GSB-11, exhibiting a strong antagonistic activity against several multidrug-resistant pathogenic bacteria. This potential strain was identified by phenotypic, genotypic (16S rRNA), and phylogenetic analyses. GSB-11 was related to "Streptomyces acrimycini" NBRC 12736 T with 99.59% similarity. Molecular screening by PCR assay demonstrated that the strain possesses two biosynthetic genes coding for NRPS and PKS-II. Two active compounds GSB11-6 and GSB11-7 were extracted from the cell-free culture supernatant of Bennett medium and purified using reversed-phase HPLC. According to spectrometric (mass spectrum) and spectroscopic (1H NMR, 13C NMR, 1H-1H COSY, and 1H-13C HMBC) spectra analyses, the compounds GSB11-6 and GSB11-7 were identified to be maculosin and N-acetyltyramine, respectively. Their minimum inhibitory concentrations (MIC) revealed interesting values against certain multidrug-resistant pathogenic bacteria. They were between 5 and 15 mg/mL for GSB11-6, 10 and 30 mg/mL for GSB11-7. To our best knowledge, this is the first study of these active substances isolated from "Streptomyces acrimycini" showing an interesting antibacterial activity. Therefore, these essential compounds could be candidates for future research against multidrug-resistant bacteria.

Permeability of dopamine D2 receptor agonist hordenine across the intestinal and blood-brain barrier in vitro.

Hordenine, a bioactive food compound, has several pharmacological properties and has recently been identified as a dopamine D2 receptor (D2R) agonist. Since the pharmacokinetic profile of hordenine has been described to a limited extent, the present study focused on the transfer and transport of hordenine across the intestinal epithelium and the blood-brain barrier (BBB) in vitro. Hordenine was quickly transferred through the Caco-2 monolayer in only a few hours, indicating a rapid oral uptake. However, the high bioavailability may be reduced by the observed efflux transport of hordenine from the bloodstream back into the intestinal lumen and by first pass metabolism in intestinal epithelial cells. To determine the biotransformation rate of hordenine, the metabolite hordenine sulfate was synthesized as reference standard for analytical purposes. In addition, transfer studies using primary porcine brain capillary endothelial cells (PBCEC) showed that hordenine is able to rapidly penetrate the BBB and potentially accumulate in the brain. Thus, a D2R interaction of hordenine and activation of dopaminergic signaling is conceivable, assuming that the intestinal barrier can be circumvented by a route of administration alternative to oral uptake.

Hordenine inhibits neuroinflammation and exerts neuroprotective effects via inhibiting NF-κB and MAPK signaling pathways in vivo and in vitro.

Parkinson's disease (PD) is a usual disease caused by degeneration of the central nervous system, which features the denaturation and death of dopaminergic neurons in the substantia nigra compact (SNc) of the midbrain. Neuroinflammation casts a consequential role in its pathogenesis, and the excessive activation of microglia as a major part of neuroinflammation cannot be ignored. Studies have indicated that Hordenine (HOR) functioned widely as an anti-oxidant and anti-inflammatory substance, but there are no reports on neuroinflammation effects. Therefore, this study is devoted to exploring the effect of HOR on neuroinflammation and its specific mechanism. In vivo, results revealed that HOR depressed the activation of microglia in SNc and protected dopaminergic neurons in the 6-hydroxydopamine (6-OHDA)-induced PD rat model, which terminally reduced movement disorders and weight loss. In vitro, studies have shown that HOR can inhibit inflammatory responses triggered by lipopolysaccharide (LPS) in BV-2 cells. More profound studies have discovered that the specific anti-inflammatory mechanism is intimately associated with the NF-κB and MAPK signaling pathways. All in it together, HOR acts as a significant role in preserving dopaminergic neurons by restraining neuroinflammation mediated by activation of microglia. This may provide a potential drug for Parkinson's treatment.

Tiered approach for evaluation of anti-melanogenic activity of trans-N-coumaroyltyramine derivatives.

Skin hyperpigmentation is commonly treated by topical drug application. Several naturally occurring compounds exhibit attractive biological effects including anti-melanogenic activity. Chemically modified derivatives of those compounds are expected to be more efficient. However, efficacy and safety testing processes are of significant consideration to identify the most effective compound among them. Herein, we demonstrated a tiered approach to investigate the antipigmentation activity of 17 trans-N-coumaroyltyramine derivatives. First, we evaluated the in chemico antityrosinase activity, then the cytotoxicity of the most potent derivatives using a mitochondrial activity-based assay, followed with the in vitro anti-melanogenic activity in two dimensional (2D) monolayer human melanocytes. The selected derivatives were topically applied on a three dimensional (3D) pigmented-reconstructed human epidermis (pRhE) containing melanocytes and keratinocytes to evaluate their depigmenting activity. Two of the 17 derivatives displayed a significant reduction in pigmentation in the 3D pRhE, comparable to kojic acid, a known tyrosinase inhibitor. In addition, a molecular docking experiment indicated an interaction of the three derivatives and tyrosinase, suggesting that these derivatives have potent anti-melanogenic activity through tyrosinase inhibition. Our findings provide an alternative approach for investigating skin-whitening agents, thereby facilitating the research and development of skin-whitening products that need not be tested on animals.

Transcriptome analysis of Leucojum aestivum and identification of genes involved in norbelladine biosynthesis.

MAIN CONCLUSION: Transcriptome analysis of Leucojum aestivum led to the identification of 50 key genes associated with Amaryllidaceae alkaloid biosynthesis including norbelladine synthase which localized in the cytosol and catalyzed norbelladine formation. The Amaryllidaceae alkaloids (AAs) are a large group of plant specialized metabolites, which are known for their biological activities. Although the general chemical reactions in the AA biosynthetic pathway have been proposed, the genes and enzymes of the pathway remain largely unstudied. All AAs are synthesized from a common precursor, norbelladine, by the condensation of tyramine and 3,4-dihydroxybenzaldehyde. The enzyme norbelladine synthase (NBS) which catalyzes the condensation reaction has only been characterized at a molecular level from one species, and the subcellular localizations have not been explored. Hence, the intracellular compartments wherein the AAs are biosynthesized remain unknown. In this study, a first comprehensive transcriptomic analysis of summer snowflake (Leucojum aestivum) was done to identify key genes associated with AA biosynthesis. Fifty orthologous genes were identified and deposited into GenBank. In addition, we identified and further characterized NBS from the transcriptome of L. aestivum and previously reported Narcissus papyraceus. Phylogenetic analysis showed that LaNBS, NpNBS1 and NpNBS2 shared high amino acid identity. The heterologous expression of LaNBS produced a recombinant protein with NBS activity. Bioinformatic prediction and C-terminal GFP tagging in transiently transformed Nicotiana benthamiana showed that LaNBS, NpNBS1 and NpNBS2 were likely localized to the cytosol which suggests that the AA biosynthesis starts in the cytosol. This study provides an Amaryllidaceae transcriptome that will be very helpful to identify genes for characterization studies in AA metabolism in planta or using heterologous systems. In addition, our study will facilitate the bioengineering of AA biosynthetic pathway in plants or in microorganisms.

GPR120 Inhibits Colitis Through Regulation of CD4+ T Cell Interleukin 10 Production.

BACKGROUND & AIMS: G protein-coupled receptor (GPR) 120 has been implicated in regulating metabolic syndromes with anti-inflammatory function. However, the role of GPR120 in intestinal inflammation is unknown. Here, we investigated whether and how GPR120 regulates CD4+ T cell function to inhibit colitis development. METHODS: Dextran sodium sulfate (DSS)-induced colitis model, Citrobacter rodentium infection model, and CD4+ T cell adoptive transfer model were used to analyze the role of GPR120 in regulating colitis development. The effect of GPR120 on CD4+ T cell functions was analyzed by RNA sequencing, flow cytometry, and Seahorse metabolic assays. Mice were administered GPR120 agonist for investigating the potential of GPR120 agonist in preventing and treating colitis. RESULTS: Deficiency of GPR120 in CD4+ T cells resulted in more severe colitis in mice upon dextran sodium sulfate insult and enteric infection. Transfer of GPR120-deficient CD4+CD45Rbhi T cells induced more severe colitis in Rag-/- mice with lower intestinal interleukin (IL) 10+CD4+ T cells. Treatment with the GPR120 agonist CpdA promoted CD4+ T cell production of IL10 by up-regulating Blimp1 and enhancing glycolysis, which was regulated by mTOR. GPR120 agonist-treated wild-type, but not IL10-deficient and Blimp1-deficient, T helper 1 cells induced less severe colitis. Furthermore, oral administration of GPR120 agonist protected mice from intestinal inflammation in both prevention and treatment schemes. Gpr120 expression was positively correlated with Il10 expression in the human colonic mucosa, including patients with inflammatory bowel diseases. CONCLUSIONS: Our findings show the role of GPR120 in regulating intestinal CD4+ T cell production of IL10 to inhibit colitis development, which identifies GPR120 as a potential therapeutic target for treating inflammatory bowel diseases.

Quantification of hordenine in a complex plant matrix by direct analysis in real time-high-resolution mass spectrometry: Application to the "plant of concern" Sceletium tortuosum.

Recently, there has been an increase in the recreational abuse of several psychoactive plants, resulting in the United Nations Office on Drugs and Crime creating a list of "plants of concern." One such material is Sceletium tortuosum and products derived from it. Regulation of these materials is challenging because of their innocuous appearance, the cumbersome sample preparation steps required to render the material into a form amenable to analysis by conventional techniques, the requirement for nuanced sample analysis protocols, and lengthy analysis times. It is demonstrated here that direct analysis in real time-high-resolution mass spectrometry (DART-HRMS) can be used to not only identify S. tortuosum material based on the detection of characteristic biomarkers including hordenine and several mesembrine alkaloids, but also quantify the amount of hordenine present. Using hordenine-d6 as an internal standard, a protocol, validated according to US Food and Drug Administration (FDA) Guidelines for the Development and Validation of Bioanalytical Methods, was devised for the quantification of the psychoactive component hordenine. The method was then applied to the quantification of hordenine in six commercially available products derived from the foliage and stems of S. tortuosum. By this method, the lower limit of quantification (LLOQ) was found to be 1 µg/ml. Observed hordenine concentrations ranged from 0.02738 to 1.071 mg of hordenine per gram of plant material. The developed technique provides an effective and quick means for the detection and quantification of hordenine in S. tortuosum, which can be extended to analysis of other hordenine-containing products.

Natural Bioactive Cinnamoyltyramine Alkylamides and Co-Metabolites.

Natural products are a vital source for agriculture, medicine, cosmetic and other fields. Among them alkylamides are a broad and expanding group found in at least 33 plant families. Frequently, they possess a simple carbon skeleton architecture but show broad structural variability and important properties such as immunomodulatory, antimicrobial, antiviral, larvicidal, insecticidal and antioxidant properties, amongst others. Despite to these several and promising biological activities, up to today, only two reviews have been published on natural alkylamides. One focuses on their potential pharmacology application and their distribution in the plant kingdom and the other one on the bioactive alkylamides specifically found in Annona spp. The present review is focused on the plant bioactive cinnamoyltyramine alkylamides, which are subject of several works reported in the literature. Furthermore, the co-metabolites isolated from the same natural sources and their biological activities are also reported.

Male fire ant neurotransmitter precursors trigger reproductive development in females after mating.

Social insect queens have evolved mechanisms to prevent competition from their sexual daughters. For Solenopsis invicta, the fire ant, queens have evolved a primer pheromone that retards reproductive development in their winged reproductive daughters. If these daughters are removed from the influence of the queen, it takes about a week to start reproductive development; however, it starts almost immediately after mating. This dichotomy has been unsuccessfully investigated for several decades. Here we show that male fire ants produce tyramides, derivatives of the biogenic amine tyramine, in their reproductive system. Males transfer tyramides to winged females during mating, where the now newly mated queens enzymatically convert tyramides to tyramine. Tyramine floods the hemolymph, rapidly activating physiological processes associated with reproductive development. Tyramides have been found only in the large Myrmicinae ant sub-family (6,800 species), We suggest that the complex inhibition/disinhibition of reproductive development described here will be applicable to other members of this ant sub-family.

Oncolytic Vaccinia Virus Harboring Aphrocallistes vastus Lectin Inhibits the Growth of Cervical Cancer Cells Hela S3.

Aphrocallistes vastus lectin (AVL) is a C-type marine lectin produced by sponges. Our previous study demonstrated that genes encoding AVL enhanced the cytotoxic effect of oncolytic vaccinia virus (oncoVV) in a variety of cancer cells. In this study, the inhibitory effect of oncoVV-AVL on Hela S3 cervical cancer cells, a cell line with spheroidizing ability, was explored. The results showed that oncoVV-AVL could inhibit Hela S3 cells growth both in vivo and in vitro. Further investigation revealed that AVL increased the virus replication, promote the expression of OASL protein and stimulated the activation of Raf in Hela S3 cells. This study may provide insight into a novel way for the utilization of lection AVL.

Glutamine synthetase regulation by dexamethasone, RU486, and compound A in astrocytes derived from aged mouse cerebral hemispheres is mediated via glucocorticoid receptor.

Glucocorticoids (GCs) regulate astrocyte function, while glutamine synthetase (GS), an enzyme highly expressed in astrocytes, is one of the most remarkable GCs-induced genes. GCs mediate their effects through their cognate glucocorticoid receptor (GRα and GRß isoforms); however, the mechanism via which these isoforms regulate GS activity in astrocytes remains unknown. We used dexamethasone (DEX), a classical GRα/GRß agonist, RU486, which is a specific GRß ligand, and Compound A, a known "dissociated" ligand, to delineate the mechanism via which GR modulates GS activity. Aged Mouse Cerebral Hemisphere astrocytes were treated with DEX (1 µM), RU486 (1 nM-1 µM) or compound A (10 µM), alone or in combination with DEX. GS activity and expression, GR isoforms (mRNA and protein levels), and GRα subcellular trafficking were measured. DEX increased GS activity in parallel with GRα nuclear translocation. RU486 increased GS activity in absence of GRα nuclear translocation implicating thus a role of GRß-mediated mechanism compound A had no effect on GS activity implicating a GRα-GRE-mediated mechanism. None of the compounds affected whole-cell GRα protein content. DEX reduced GRα and GRß mRNA levels, while RU486 increased GRß gene expression. We provide evidence that GS activity, in astrocytes, is regulated via GRα- and GRß-mediated pathways with important implications in pathological conditions in which astrocytes are involved.

Amaryllidaceae Alkaloids of Norbelladine-Type as Inspiration for Development of Highly Selective Butyrylcholinesterase Inhibitors: Synthesis, Biological Activity Evaluation, and Docking Studies.

Alzheimer's disease (AD) is a multifactorial neurodegenerative condition of the central nervous system (CNS) that is currently treated by cholinesterase inhibitors and the N-methyl-d-aspartate receptor antagonist, memantine. Emerging evidence strongly supports the relevance of targeting butyrylcholinesterase (BuChE) in the more advanced stages of AD. Within this study, we have generated a pilot series of compounds (1-20) structurally inspired from belladine-type Amaryllidaceae alkaloids, namely carltonine A and B, and evaluated their acetylcholinesterase (AChE) and BuChE inhibition properties. Some of the compounds exhibited intriguing inhibition activity for human BuChE (hBuChE), with a preference for BuChE over AChE. Seven compounds were found to possess a hBuChE inhibition profile, with IC50 values below 1 µM. The most potent one, compound 6, showed nanomolar range activity with an IC50 value of 72 nM and an excellent selectivity pattern over AChE, reaching a selectivity index of almost 1400. Compound 6 was further studied by enzyme kinetics, along with in-silico techniques, to reveal the mode of inhibition. The prediction of CNS availability estimates that all the compounds in this survey can pass through the blood-brain barrier (BBB), as disclosed by the BBB score.

Trace Amine-Associated Receptor 1 Contributes to Diverse Functional Actions of O-Phenyl-Iodotyramine in Mice but Not to the Effects of Monoamine-Based Antidepressants.

Trace Amine-Associated Receptor 1 (TAAR1) is a potential target for the treatment of depression and other CNS disorders. However, the precise functional roles of TAAR1 to the actions of clinically used antidepressants remains unclear. Herein, we addressed these issues employing the TAAR1 agonist, o-phenyl-iodotyramine (o-PIT), together with TAAR1-knockout (KO) mice. Irrespective of genotype, systemic administration of o-PIT led to a similar increase in mouse brain concentrations. Consistent with the observation of a high density of TAAR1 in the medial preoptic area, o-PIT-induced hypothermia was significantly reduced in TAAR1-KO mice. Furthermore, the inhibition of a prepulse inhibition response by o-PIT, as well as its induction of striatal tyrosine hydroxylase phosphorylation and elevation of extracellular DA in prefrontal cortex, were all reduced in TAAR1-KO compared to wildtype mice. O-PIT was active in both forced-swim and marble-burying tests, and its effects were significantly blunted in TAAR1-KO mice. Conversely, the actions on behaviour and prefrontal cortex dialysis of a broad suite of clinically used antidepressants were unaffected in TAAR1-KO mice. In conclusion, o-PIT is a useful tool for exploring the hypothermic and other functional antidepressant roles of TAAR1. By contrast, clinically used antidepressants do not require TAAR1 for expression of their antidepressant properties.

Liver fat storage is controlled by HNF4α through induction of lipophagy and is reversed by a potent HNF4α agonist.

We report the discovery of strong HNF4α agonists and their use to uncover a previously unknown pathway by which HNF4α controls the level of fat storage in the liver. This involves the induction of lipophagy by dihydroceramides, the synthesis and secretion of which is controlled by genes induced by HNF4α. The HNF4α activators are N-trans caffeoyltyramine (NCT) and N-trans feruloyltyramine (NFT), which are structurally related to the known drugs alverine and benfluorex, which we previously showed to be weak HNF4α activators. In vitro, NCT and NFT induced fat clearance from palmitate-loaded cells. In DIO mice, NCT led to recovery of hepatic HNF4α expression and reduction of steatosis. Mechanistically, increased dihydroceramide production and action downstream of HNF4α occurred through increased expression of HNF4α downstream genes, including SPNS2 and CYP26A1. NCT was completely nontoxic at the highest dose administered and so is a strong candidate for an NAFLD therapeutic.

Is Riparin III a promising drug in the treatment for depression?

Stress is crucially related to the pathophysiology of mood disorders, including depression. Since the effectiveness and number of the current pharmacological options still presents significant limitations, research on new substances is paramount. In rodents, several findings have indicated that corticosterone administration induces the manifestation of behavioral and neurochemical aspects of depression. Recently, riparin III has shown antidepressant-like properties in trials performed on animal models. Thus, our goal was to investigate the effects of riparin III on behavioral tests, monoamines levels, oxidative stress and cytokines levels in chronic corticosterone-induced model of depression. To do this, female swiss mice were treated with subcutaneous administration of corticosterone for 22 days. In addition, for the last 10 days, riparin III or fluvoxamine were also administered per os in specific test groups. Control groups received subcutaneous saline injections or distilled water per os. At the end of the timeline, the animals were killed and their hippocampi, prefrontal cortex, and striatum dissected for neurochemical analysis. Brain changes following corticosterone administration were confirmed, and riparin III could reversed the most abnormal behavioral and neurochemical corticosterone-induced alterations. These results suggest the potential antioxidant, anti-inflammatory and antidepressant effects of riparin III after a chronic stress exposure.