Testosterone amplifies excitotoxic damage of cultured oligodendrocytes

An overactivation of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA)/kainate receptors has been implicated in the pathophysiology of oligodendrocyte damage in demyelinating disorders of the CNS. We decided to examine the effect of testosterone on excitotoxic death of oligodendrocytes because a gender difference exists in the incidence and disease course of multiple sclerosis. Short-term pure cultures of oligodendrocytes (4 days in vitro) were exposed to a brief pulse with kainate or AMPA + cyclothiazide for the induction of excitotoxicity. Exposure to testosterone enantate was slightly toxic per se and amplified both AMPA and kainate toxicity. Testosterone treatment induced all gene targets of p53, and amplified the induction of these genes induced by kainate. The effect of testosterone was mediated by the activation of androgen receptors and was resistant to the aromatase inhibitors, dl-aminoglutethimide and 4-hydroxyandrost-4-ene-3,17-dione. Testosterone treatment also potentiated the stimulation of 45Ca2+ influx induced by AMPA + cyclothiazide or kainate without changing the expression of the glutamate receptor (GluR) 1, -2/3, and -4 subunits of AMPA receptors or the GluR6/7 subunits of kainate receptors. We conclude that testosterone amplifies excitotoxic damage of oligodendrocytes acting at an early step of the death cascade triggered by AMPA/kainate receptors.     

Vascular progenitors derived from murine bone marrow stromal cells are regulated by fibroblast growth factor and are avidly recruited by vascularizing tumors

Bone marrow-derived stromal cells (BMSC) possess a population of vascular progenitor cells that enable them to acquire a histology and immunophenotype coherent with endothelial cells (EC). Recent evidence indicates that a hypoxic environment such as that encountered in tumor masses regulates BMSC angiogenic properties by pathways that remain to be defined. It is also unclear as to what extent these marrow-derived precursor cells could contribute to the growth of endothelium-lined vessels at the vicinity of tumor masses. In this study, we found that BMSC exhibited the ability to generate three-dimensional capillary-like networks on Matrigel, and that this property was up-regulated by growth factors-enriched conditioned media isolated from several tumor-derived cell lines. In particular, basic fibroblast growth factor, a key mediator of angiogenesis, was found to be the most potent growth factor for inducing BMSC proliferation, migration, and tubulogenesis. The setup of a new two-dimensional in vitro co-culture assay further showed that BMSC were massively recruited when cultured in the presence of either cancerous or differentiated EC lines. In vivo, subcutaneous co-injection of BMSC with U-87 glioma cells in nude mice resulted in the formation of highly vascularized tumors, where BMSC differentiated into CD31-positive cells and localized at the lumen of vascular structures. Our data suggest that BMSC could be recruited at the sites of active tumor neovascularization through paracrine regulation of their angiogenic properties. These observations may have crucial implications in the development of novel therapies using BMSC engineered to secrete anti-cancerous agents and to antagonize tumor progression.     

Extracellular matrix and visual cortical plasticity: freeing the synapse

The effects of monocular deprivation (MD) on the ocular dominance of visual cortical neurons are a paradigmatic example of experience-dependent plasticity. Here we review recent data showing that extracellular matrix (ECM) plays an important role in the control of experience-dependent plasticity both in the developing and adult visual cortex.     

Structure-activity relationship studies on unifiram (DM232) and sunifiram (DM235), two novel and potent cognition enhancing drugs

Structure-activity relationships on two novel potent cognition enhancing drugs, unifiram (DM232, 1) and sunifiram (DM235, 2), are reported. Although none of the compounds synthesised reached the potency of the parent drugs, some fairly active compounds have been identified that may represent new leads to develop other cognition enhancing drugs. An interesting result of this research is the identification of two compounds (13 and 14) that are endowed with amnesing activity (the opposite of the activity of the original molecules) and are nearly equipotent to scopolamine. Moreover, two compounds of the series (5 and 6) were found endowed with analgesic activity on a rat model of neuropathic pain at the dose of 1 mg/kg.     

Propranolol,a β-adrenoceptor antagonist,worsens liver injury in a model of non-alcoholic steatohepatitis

Prazosin an α1-adrenoceptor (AR) antagonist has been shown to reduce liver injury in a mouse model of non-alcoholic steatohepatitis (NASH) and is suggested as a potential treatment of NASH especially given its concomitant anti-fibrotic properties. The effect however, of β-AR blockade in non-cirrhotic NASH is unknown and is as such investigated here. In the presence of the β-blocker propranolol (PRL), mice fed normal chow or a half methionine and choline deficient diet, supplemented with ethionine (HMCDE), to induce NASH, showed significantly enhanced liver injury, as evidenced by higher hepatic necrosis scores and elevated serum aminotransferases (ALT). Mechanistically, we showed that murine hepatocytes express α and β adrenoceptors; that PRL directly induces hepatocyte injury and death as evidenced by increased release of lactate dehydrogenase, FASL and TNF-α from hepatocytes in the presence of PRL; and that PRL activated the apoptotic pathway in primary hepatocyte cultures, as indicated by upregulation of Fas receptor and caspase-8 proteins. The β-AR antagonist PRL therefore appears to enhance liver injury through induction of hepatocyte death via the death pathway. Further studies are now required to extrapolate these findings to humans but meanwhile, β-AR antagonists should be avoided or used with caution in patients with non-cirrhotic NASH as they may worsen liver injury.     

New N-acyl-d-glucosamine 2-epimerases from cyanobacteria with high activity in the absence of ATP and low inhibition by pyruvate

N-Acetylneuraminic acid, an important component of glycoconjugates with various biological functions, can be produced from N-acetyl-d-glucosamine (GlcNAc) and pyruvate using a one-pot, two-enzyme system consisting of N-acyl-d-glucosamine 2-epimerase (AGE) and N-acetylneuraminate lyase (NAL). In this system, the epimerase catalyzes the conversion of GlcNAc into N-acetyl-d-mannosamine (ManNAc). However, all currently known AGEs have one or more disadvantages, such as a low specific activity, substantial inhibition by pyruvate and strong dependence on allosteric activation by ATP. Therefore, four novel AGEs from the cyanobacteria Acaryochloris marina MBIC 11017, Anabaena variabilis ATCC 29413, Nostoc sp. PCC 7120, and Nostoc punctiforme PCC 73102 were characterized. Among these enzymes, the AGE from the Anabaena strain showed the most beneficial characteristics. It had a high specific activity of 117 ± 2 U mg⁻¹ at 37 °C (pH 7.5) and an up to 10-fold higher inhibition constant for pyruvate as compared to other AGEs indicating a much weaker inhibitory effect. The investigation of the influence of ATP revealed that the nucleotide has a more pronounced effect on the K_m for the substrate than on the enzyme activity. At high substrate concentrations (≥200 mM) and without ATP, the enzyme reached up to 32% of the activity measured with ATP in excess.     

Persistence of bactericidal antibodies following early infant vaccination with a serogroup B meningococcal vaccine and immunogenicity of a preschool booster dose

Background:

The multicomponent serogroup B meningococcal (4CMenB) vaccine was recently licensed for use in Europe. There are currently no data on the persistence of bactericidal antibodies induced by use of this vaccine in infants. Our objective was to evaluate serogroup B–specific bactericidal antibodies in children aged 40–44 months previously vaccinated at 2, 4, 6 and 12 months of age.

Methods:

Participants given 4 doses of 4CMenB as infants received a fifth dose of the vaccine at 40–44 months of age. Age-matched participants who were MenB vaccine–naive received 4CMenB and formed the control group. We evaluated human complement serum bactericidal activity (hSBA) titres at baseline and 1 month after each dose of 4CMenB.

Results:

Before a booster dose at enrolment, 41%–76% of 17 participants previously vaccinated with 4CMenB in infancy had hSBA titres of 4 or greater against 4 reference strains. Before vaccination in the control group (n = 40) these proportions were similar for strains 44/76-SL (63%) and {"type":"entrez-nucleotide","attrs":{"text":"M10713","term_id":"209124","term_text":"M10713"}}M10713 (68%) but low for strains NZ98/254 (0%) and 5/99 (3%). A booster dose in the 4CMenB-primed participants generated greater increases in hSBA titres than in controls.

Interpretation:

As has been observed with other meningococcal vaccines, bactericidal antibodies waned after vaccination with 4CMenB administered according to an approved infant vaccination schedule of 2, 4, 6 and 12 months of age, but there was an anamnestic response to a booster dose at 40–44 months of age. If 4CMenB were introduced into routine vaccination schedules, assessment of the need for a booster dose would require data on the impact of these declining titres on vaccine effectiveness. ClinicalTrials.gov, no. {"type":"clinical-trial","attrs":{"text":"NCT01027351","term_id":"NCT01027351"}}NCT01027351A vaccine against serogroup B meningococcus has recently been licensed for use in Europe¹ and is being considered for licensure in Canada. This vaccine, known as multicomponent serogroup B meningococcal (4CMenB) vaccine, consists of 3 recombinant proteins: factor H binding protein (fHbp), Neisseria adhesin A (NadA) and Neisseria heparin binding antigen (NHBA) combined with detoxified outer membrane vesicles from the strain responsible for an epidemic of serogroup B meningococcal disease in New Zealand (NZ98/254). Clinical trials of 4CMenB have shown it to be immunogenic against reference strains selected to speciScally express one of the vaccine antigens.^2–6 On the basis of these trials, the approved schedule for infants aged 2 to 5 months is 3 doses given at least 1 month apart, with a booster dose given at 12 to 23 months of age.⁷ The persistence of vaccine-induced antibodies throughout childhood following this booster dose is unknown, but it is particularly relevant because the incidence of invasive serogroup B meningococcal disease in children aged 1 to 4 years is second only to the incidence in children less than 1 year of age.⁸In this study, we assessed the persistence of these bactericidal antibodies in children aged 40–44 months who had previously received either 4CMenB or a vaccine containing the recombinant proteins alone (recombinant protein serogroup B meningococcal [rMenB] vaccine) at 2, 4, 6 and 12 months of age.³ We also assessed the immunogenicity and reactogenicity of a booster dose.     

Discovery of NMS-E973 as novel,selective and potent inhibitor of heat shock protein 90 (Hsp90)

Novel small molecule inhibitors of heat shock protein 90 (Hsp90) were discovered with the help of a fragment based drug discovery approach (FBDD) and subsequent optimization with a combination of structure guided design, parallel synthesis and application of medicinal chemistry principles. These efforts led to the identification of compound 18 (NMS-E973), which displayed significant efficacy in a human ovarian A2780 xenograft tumor model, with a mechanism of action confirmed in vivo by typical modulation of known Hsp90 client proteins, and with a favorable pharmacokinetic and safety profile.     

Identification of RC-33 as a potent and selective σ1 receptor agonist potentiating NGF-induced neurite outgrowth in PC12 cells. Part 2: g-Scale synthesis,physicochemical characterization and in vitro metabolic stability

Strong pharmacological evidences indicate that σ1 receptors are implicated in the pathophysiology of all major CNS disorders. In the last years our research group has conducted extensive studies aimed at discovering novel σ1 ligands and we recently selected (R/S)-RC-33 as a novel potent and selective σ1 receptor agonist. As continuation of our work in this field, here we report our efforts in the development of this new σ1 receptor agonist. Initially, we investigated the binding of (R) and (S) enantiomers of RC-33 to the σ1 receptor by in silico experiments. The close values of the predicted affinity of (R)-RC-33 and (S)-RC-33 for the protein evidenced the non-stereoselective binding of RC-33 to the σ1 receptor; this, in turn, supported further development and characterization of RC-33 in its racemic form. Subsequently, we set-up a scaled-up, optimized synthesis of (R/S)-RC-33 along with some compound characterization data (e.g., solubility in different media and solid state characterization by thermal analysis techniques). Finally, metabolic studies of RC-33 in different biological matrices (e.g., plasma, blood, and hepatic S9 fraction) of different species (e.g., rat, mouse, dog, and human) were performed. (R/S)-RC-33 is generally stable in all examined biological matrices, with the only exception of rat and human liver S9 fractions in the presence of NADPH. In such conditions, the compound is subjected to a relevant oxidative metabolism, with a degradation of approximately 65% in rat and 69% in human.Taken together, our results demonstrated that (R/S)-RC-33 is a highly potent, selective, metabolically stable σ1 agonist, a promising novel neuroprotective drug candidate.     

Habitat degradation impacts black howler monkey (Alouatta pigra) gastrointestinal microbiomes

The gastrointestinal (GI) microbiome contributes significantly to host nutrition and health. However, relationships involving GI microbes, their hosts and host macrohabitats remain to be established. Here, we define clear patterns of variation in the GI microbiomes of six groups of Mexican black howler monkeys (Alouatta pigra) occupying a gradation of habitats including a continuous evergreen rainforest, an evergreen rainforest fragment, a continuous semi-deciduous forest and captivity. High throughput microbial 16S ribosomal RNA gene sequencing indicated that diversity, richness and composition of howler GI microbiomes varied with host habitat in relation to diet. Howlers occupying suboptimal habitats consumed less diverse diets and correspondingly had less diverse gut microbiomes. Quantitative real-time PCR also revealed a reduction in the number of genes related to butyrate production and hydrogen metabolism in the microbiomes of howlers occupying suboptimal habitats, which may impact host health.