Non Digestible Oligosaccharides Modulate the Gut Microbiota to Control the Development of Leukemia and Associated Cachexia in Mice

We tested the hypothesis that changing the gut microbiota using pectic oligosaccharides (POS) or inulin (INU) differently modulates the progression of leukemia and related metabolic disorders. Mice were transplanted with Bcr-Abl-transfected proB lymphocytes mimicking leukemia and received either POS or INU in their diet (5%) for 2 weeks. Combination of pyrosequencing, PCR-DGGE and qPCR analyses of the 16S rRNA gene revealed that POS decreased microbial diversity and richness of caecal microbiota whereas it increased Bifidobacterium spp., Roseburia spp. and Bacteroides spp. (affecting specifically B. dorei) to a higher extent than INU. INU supplementation increased the portal SCFA propionate and butyrate, and decreased cancer cell invasion in the liver. POS treatment did not affect hepatic cancer cell invasion, but was more efficient than INU to decrease the metabolic alterations. Indeed, POS better than INU delayed anorexia linked to cancer progression. In addition, POS treatment increased acetate in the caecal content, changed the fatty acid profile inside adipose tissue and counteracted the induction of markers controlling β-oxidation, thereby hampering fat mass loss. Non digestible carbohydrates with prebiotic properties may constitute a new nutritional strategy to modulate gut microbiota with positive consequences on cancer progression and associated cachexia.     

Rapid estimation of potential yield for data-poor Tapes philippinarum fisheries in North Adriatic coastal lagoons

We show how a simple species distribution model can be used for the rapid estimation of potential yield and for the identification of suitable sites for farming of Tapes philippinarum in two North Adriatic lagoons (Caleri and Marinetta-Vallona, Italy) in the face of limited data. We used a two-part species distribution model with sediment type, hydrodynamism, dissolved oxygen, and salinity as predictors of T. philippinarum potential yield. The first model component uses logistic regression to identify the areas in which clams occur, while the second component uses a weighted geometric mean of suitability values to estimate the potential annual yield (kg m^?2 year^?1) for the sites where T. philippinarum is predicted to be present. We used site-specific yield data from Caleri and Marinetta-Vallona to estimate the weights of the geometric mean by constrained linear regression. We validated the two-part model on an independent set of yield data (R _adj ²  = 0.82), and we then estimated the spatial distribution of potential yield in the two lagoons. The calibration and application of a simple species distribution model are useful tools for objectively identifying the most suitable sites for farming of T. philippinarum in North Adriatic lagoons.     

Persistent facial pain increases superoxide anion production in the spinal trigeminal nucleus

Previous studies have demonstrated that there is an increase in oxidative stress in the cerebral cortex of rats after repeated painful stimulation and that long-lasting pain increases the production of superoxide ion (O₂ ^?), nitric oxide and peroxynitrite due to the activation of AMPA and NMDA receptors. The purpose of the present study was to evaluate the possible role of O₂ ^? in the transmission of oro-facial pain. Formaldehyde 1% was injected subcutaneously into one vibrissal pad of adult male Sprague-Dawley rats as a model of persistent pain, then O₂ ^? production and superoxide dismutase (SOD) activity were evaluated in the left and right spinal trigeminal nuclei. O₂ ^? production was revealed using dihidroetidium (DHE) injected at 10 or 45 min after the formalin injection in conscious or anaesthetized rats. A histochemical assay for SOD was performed to evaluate the activity of SOD at 10 min after the formalin injection. The results showed a significant increase in O₂ ^? production in the homolateral nucleus at 45 min. However, there was no significant difference between the two sides at 10 min after the formalin injection. No significant difference was observed in SOD activity between the two sides of the spinal trigeminal nucleus. This study demonstrated that there is an increased production of O₂ ^? in the second phase but not in the first phase of the formalin test; thus O₂ ^? is involved in pain induced by inflammation, but not in acute pain.     

Transglutaminase participates in the blockade of neurotransmitter release by tetanus toxin: evidence for a novel biological function

The aim of this study was to collect evidences on the role of transglutaminase (TG, E.C.2.3.2.13) in the antineoplastic properties exerted by nimesulide (NMS), a non-steroidal anti-inflammatory drug, on murine B16-F10 melanoma cells. Treatment of melanoma cells with nimesulide produces a considerable reduction of cell proliferation, paralleled by a remarkable decrease of the intracellular concentration of polyamines spermidine and spermine. NMS treatment induces cancer cell differentiation, likely through the observed enhancement of TG and tyrosinase activities and increase of melanin production, well known markers of melanocyte differentiation. The overall results highlight the possibility that nimesulide acts as antineoplastic agent likely through the induction of intracellular TG activity.     

The role of Sirt1: At the crossroad between promotion of longevity and protection against Alzheimer's disease neuropathology

Sirt1, a mammalian member of the sirtuin gene family, holds great potential for promoting longevity, preventing against disease and increasing cell survival. For example, studies suggest that the beneficial impact of caloric restriction in promoting longevity and cellular function may be mediated, in part, by Sirt1 through mechanisms involving PGC-1α, which plays important role in the regulation of cellular metabolism and inflammatory and antioxidant responses. Sirt1 may also interfere with mechanisms implicated in pathological disorders. We will present recent evidence indicating that Sirt1 may protect against Alzheimer's disease by interfering with the generation of β-amyloid peptides. We will discuss Sirt1 as a potential novel target, in addition to the development of Sirt1 activators for the prevention and treatment of Alzheimer's disease.     

Synthesis, structural and spectroscopic characterization and biomimetic properties of new copper, manganese, zinc complexes: Identification of possible superoxide-dismutase mimics bearing hydroxyl radical generating/scavenging abilities

A series of Cu(II), Zn(II) and Mn(II) coordination compounds has been synthesized by reaction of the corresponding metal salts and pyrazolyl-based ligands, i.e. the neutral 1-(2-(4-((2,2,2-tri(1H-pyrazol-1-yl)ethoxy)methyl)benzyloxy)-1,1-di(1H-pyrazol-1-yl)ethyl)-1H-pyrazole {p-C₆H₄[CH₂OCH₂C(pz)₃]₂, (L¹), and the anionic hydridotris(3-phenyl-5-methylpyrazolyl)borate (L²)⁻, bis(pyrazolyl)acetate (L³) and bis(3,5-dimethylpyrazolyl)acetate (L⁴)⁻: the species [L¹(CuCl₂)₂] (1), [L¹(Cu(OAc)₂)₂] (2), [L¹(Zn(OAc)₂)₂] (3), [(CuCl(L²)(Hpz^Ph,Me)] (4), [Mn(L³)₂]·2H₂O, (5), [ZnCl(L³)(imH)]·MeOH [CuCl(L⁴)(imH)]·2H₂O (7) have been obtained (Hpz^Ph,Me = 3-phenyl-5-methylpyrazole, imH = imidazole). Complexes 1 and 4 have been structurally characterized, also using less conventional powder diffraction methods. The superoxide scavenging activity has been characterized by indirect assays including EPR analysis. All complexes exhibit superoxide scavenging activity with IC₅₀ in the µM range and they protect against the oxidative action of peroxynitrite in different ways. 1, 4 and 7 exert both an anti- and pro-oxidant effect depending on their concentration as evaluated by EPR and fluorescence methods. The pro-oxidative effects are absent in Zn(II) and Mn(II) complexes.     

Surface adsorption of protein corona controls the cell internalization mechanism of DC-Chol-DOPE/DNA lipoplexes in serum

Serum has often been reported as a barrier to efficient lipid-mediated transfection. Here we found that the transfection efficiency of DC-Chol-DOPE/DNA lipoplexes increases in serum. To provide insight into the mechanism of lipoplex-serum interaction, several state-of-the-art methodologies have been applied. The nanostructure of DC-Chol-DOPE/DNA lipoplexes was found to be serum-resistant as revealed by high resolution synchrotron small angle X-ray scattering, while dynamic light scattering measurements showed a marked size increase of complexes. The structural stability of DC-Chol-DOPE/DNA lipoplexes was confirmed by electrophoresis on agarose gel demonstrating that plasmid DNA remained well protected by lipids. Proteomics experiments showed that serum proteins competed for the cationic surface of lipid membranes leading to the formation of a rich a ‘protein corona’. Combining structural results with proteomics findings, we suggest that such a protein corona can promote large aggregation of intact lipoplexes. According to a recently proposed size-dependent mechanism of lipoplex entry within cells, protein corona-induced formation of large aggregates most likely results in a switch from a clathrin-dependent to caveolae-mediated entry pathway into the cells which is likely to be responsible for the observed transfection efficiency boost. As a consequence, we suggest that surface adsorption of protein corona can have a high biological impact on serum-resistant cationic formulations for in vitro and in vivo lipid-mediated gene delivery applications.     

Involvement of KCNQ2 subunits in [3H]dopamine release triggered by depolarization and pre-synaptic muscarinic receptor activation from rat striatal synaptosomes

KCNQ2 and KCNQ3 subunits encode for the muscarinic-regulated current (I(KM)), a sub-threshold voltage-dependent K+ current regulating neuronal excitability. In this study, we have investigated the involvement of I(KM) in dopamine (DA) release from rat striatal synaptosomes evoked by elevated extracellular K+ concentrations ([K+]e) and by muscarinic receptor activation. [3H]dopamine ([3H]DA) release triggered by 9 mmol/L [K+]e was inhibited by the I(KM) activator retigabine (0.01-30 micromol/L; Emax = 54.80 +/- 3.85%; IC50 = 0.50 +/- 0.36 micromol/L). The I(KM) blockers tetraethylammonium (0.1-3 mmol/L) and XE-991 (0.1-30 micromol/L) enhanced K+-evoked [3H]DA release and prevented retigabine-induced inhibition of depolarization-evoked [3H]DA release. Retigabine-induced inhibition of K+-evoked [3H]DA release was also abolished by synaptosomal entrapment of blocking anti-KCNQ2 polyclonal antibodies, an effect prevented by antibody pre-absorption with the KCNQ2 immunizing peptide. Furthermore, the cholinergic agonist oxotremorine (OXO) (1-300 micromol/L) potentiated 9 mmol/L [K+]e-evoked [3H]DA release (Emax = 155 +/- 9.50%; EC50 = 25 +/- 1.80 micromol/L). OXO (100 micromol/L)-induced [3H]DA release enhancement was competitively inhibited by pirenzepine (1-10 nmol/L) and abolished by the M3-preferring antagonist 4-diphenylacetoxy N-methylpiperidine methiodide (1 micromol/L), but was unaffected by the M1-selective antagonist MT-7 (10-100 nmol/L) or by Pertussis toxin (1.5-3 microg/mL), which uncouples M2- and M4-mediated responses. Finally, OXO-induced potentiation of depolarization-induced [3H]DA release was not additive to that produced by XE-991 (10 micromol/L), was unaffected by retigabine (10 micromol/L), and was abolished by synaptosomal entrapment of anti-KCNQ2 antibodies. Collectively, these findings indicate that, in rat striatal nerve endings, I(KM) channels containing KCNQ2 subunits regulate depolarization-induced DA release and that I(KM) suppression is involved in the reinforcement of depolarization-induced DA release triggered by the activation of pre-synaptic muscarinic heteroreceptors.     

Reinvestigation of a selenopeptide with purportedly high glutathione peroxidase activity

A 15-amino acid long selenopeptide (15SeP) was recently reported to possess nearly the same catalytic activity as glutathione peroxidase (Gpx) for the reduction of hydrogen peroxide by glutathione (Sun, Y., Li, T. Y., Chen, H., Zhang, K., Zheng, K. Y., Mu, Y., Yan, G. L., Li, W., Shen, J. C., and Luo, G. M. (2004) J. Biol. Chem. 279, 37235-37240). Such a finding is startling considering the high efficiency of the natural enzyme and the modest catalytic properties of most short peptides. As 15SeP had been subjected only to limited chemical characterization, we prepared it by a new route involving selenocysteine-mediated native chemical ligation. High resolution matrix-assisted laser desorption ionization mass spectrometry confirmed the identity of the reaction product, whereas circular dichroism spectroscopy showed that 15SeP assumes a random coil conformation in solution. Although low levels of peroxidase activity were detectable under standard assay conditions, the peptide is >5 orders of magnitude less active than native Gpx. Our observations are incompatible with claims ascribing remarkable catalytic properties to 15SeP and suggest that the efficiency of Gpx derives from its well defined three-dimensional structure.