Contribution of genetic and epigenetic mechanisms to Wnt pathway activity in prevalent skeletal disorders

We reported previously that the expression of Wnt-related genes is lower in osteoporotic hip fractures than in osteoarthritis. We aimed to confirm those results by analyzing β-catenin levels and explored potential genetic and epigenetic mechanisms involved.     

Brain changes in BDNF and S100B induced by ketogenic diets in Wistar rats

AimsWe investigated the effects of ketogenic diet (KD) on levels of tumor necrosis factor alpha (TNF-α, a classical pro-inflammatory cytokine), BDNF (brain-derived neurotrophic factor, commonly associated with synaptic plasticity), and S100B, an astrocyte neurotrophic cytokine involved in metabolism regulation.Main methodsYoung Wistar rats were fed during 8 weeks with control diet or two KD, containing different proportions of omega 6 and omega 3 polyunsaturated fatty acids. Contents of TNF-α, BDNF and S100B were measured by ELISA in two brain regions (hippocampus and striatum) as well as blood serum and cerebrospinal fluid.Key findingsOur data suggest that KD was able to reduce the levels of BDNF in the striatum (but not in hippocampus) and S100B in the cerebrospinal fluid of rats. These alterations were not affected by the proportion of polyunsaturated fatty acids offered. No changes in S100B content were observed in serum or analyzed brain regions. Basal TNF-α content was not affected by KD.SignificanceThese findings reinforce the importance of this diet as an inductor of alterations in the brain, and such changes might contribute to the understanding of the effects (and side effects) of KD in brain disorders.     

The antimicrobial activity of lapachol and its thiosemicarbazone and semicarbazone derivatives

Lapachol was chemically modified to obtain its thiosemicarbazone and semicarbazone derivatives. These compounds were tested for antimicrobial activity against several bacteria and fungi by the broth microdilution method. The thiosemicarbazone and semicarbazone derivatives of lapachol exhibited antimicrobial activity against the bacteria Enterococcus faecalis and Staphylococcus aureus with minimal inhibitory concentrations (MICs) of 0.05 and 0.10 µmol/mL, respectively. The thiosemicarbazone and semicarbazone derivatives were also active against the pathogenic yeast Cryptococcus gattii (MICs of 0.10 and 0.20 µmol/mL, respectively). In addition, the lapachol thiosemicarbazone derivative was active against 11 clinical isolates of Paracoccidioides brasiliensis, with MICs ranging from 0.01-0.10 µmol/mL. The lapachol-derived thiosemicarbazone was not cytotoxic to normal cells at the concentrations that were active against fungi and bacteria. We synthesised, for the first time, thiosemicarbazone and semicarbazone derivatives of lapachol. The MICs for the lapachol-derived thiosemicarbazone against S. aureus, E. faecalis, C. gattii and several isolates of P. brasiliensis indicated that this compound has the potential to be developed into novel drugs to treat infections caused these microbes.     

Procyanidins can interact with Caco-2 cell membrane lipid rafts: Involvement of cholesterol

Large procyanidins (more than three subunits) are not absorbed at the gastrointestinal tract but could exert local effects through their interactions with membranes. We previously showed that hexameric procyanidins (Hex), although not entering cells, interact with membranes modulating cell signaling and fate. This paper investigated if Hex, as an example of large procyanidins, can selectively interact with lipid rafts which could in part explain its biological actions. This mechanism was studied in both synthetic membranes (liposomes) and Caco-2 cells. Hex promoted Caco-2 cell membrane rigidification and dehydration, effects that were abolished upon cholesterol depletion with methyl-β-cyclodextrin (MCD). Hex prevented lipid raft structure disruption induced by cholesterol depletion/redistribution by MCD or sodium deoxycholate. Supporting the involvement of cholesterol–Hex bonding in Hex interaction with lipid rafts, the absence of cholesterol markedly decreased the capacity of Hex to prevent deoxycholate- and Triton X-100-mediated disruption of lipid raft-like liposomes. Stressing the functional relevance of this interaction, Hex mitigated lipid raft-associated activation of the extracellular signal-regulated kinases (ERK) 1/2. Results support the capacity of a large procyanidin (Hex) to interact with membrane lipid rafts mainly through Hex–cholesterol bondings. Procyanidin–lipid raft interactions can in part explain the capacity of large procyanidins to modulate cell physiology.     

Qualitative and quantitative analysis of carrageenan content in gametophytes of Mastocarpus stellatus (Stackhouse) Guiry along Galician coast (NW Spain)

Qualitative and quantitative differences in carrageenan composition of gametophytes of the rhodophyte Mastocarpus stellatus (Gigartinales) were observed in this study. Carrageenans in gametophytes belong to the kappa family (κ-, ι-, ν-, μ-carrageenan). The dominant fractions were κ- and ι-carrageenan (more than 80 % of the total carrageenans). Mean total carrageenan content in gametophytes was of 37.32?±?1.21 % DW. Spatial and seasonal variations were observed, mainly related to changes on environmental and oceanographic factors and the role of carrageenans in adapting the fronds to these changes. Maximum values in carrageenan content were observed for San Román (Biscay Bay) in May and for Laxe and Mougás (Atlantic coast) in June. The results of this study indicated that spatial differences in carrageenan content were due to interactions of different factors, rather than the effect of a single factor. Fronds from San Román had higher carrageenan content (43.23?±?1.87 % DW) than those collected at two sites of the Atlantic coast, Mougás and Laxe (32.20?±?1.14 % DW). San Román is exposed to the open sea, windy and oriented to the north, and the water temperature is higher in summer than in the Atlantic coast. However, seasonal variations in carrageenan content resulted to be more related to other factors directly correlated with the input of energy in the ecosystems (irradiance, sunshine hours and insolation). Thus, carrageenan content began to increase in early spring when the number of sunlight hours increased. Maximum values were reached in late spring or early summer, just before maximum values of irradiance and air temperature were achieved.     

Membrane effects of cocoa procyanidins in liposomes and Jurkat T cells

We investigated the effects of the interaction between flavanols and related procyanidins (dimer to hexamer) with both cell and synthetic membranes, on bilayer fluidity and susceptibility to oxidation. Cocoa derived dimers (0.05 to 1 microg/ml) protected Jurkat T cells from AMVN-mediated oxidation and increased plasma membrane fluidity. These effects occurred in a concentration- and chain length-dependent manner. In liposomes, procyanidins prevented the Fe2+ -induced permeabilization of the membrane. Together, these results support the hypothesis that procyanidins could interact with the polar headgroup of lipids, increasing membrane fluidity and also, preventing the access of molecules that could affect membrane integrity.     

New class of potent antinociceptive and antiplatelet 10H-phenothiazine-1-acylhydrazone derivatives

In this work, we reported the synthesis and evaluation of the analgesic, antiinflammatory, and antiplatelet properties of new phenothiazine-attached acylhydrazone derivatives (6), designed exploring the molecular hybridization approach between antipsychotic chlorpromazine (4) and other heterocyclic derivatives (3) and (5) developed at LASSBio. Target compounds were synthesized in very good yields exploiting diphenylamine (7) as starting material, through regioselective functionalization of the C-1 position of 10H-phenothiazine ring. The evaluation of platelet antiaggregating profile lead us to identify a new potent prototype of antiplatelet derivative, that is (6a) (IC(50)=2.3 microM), which acts in arachidonic acid pathway probably by inhibition of platelet COX-1 enzyme. Additionally, the change of para-substituent group of acylhydrazone framework permitted us to identify hydrophilic carboxylate derivative (6g) and hydrophobic bromo derivative (6b) as two new leads of analgesics more active than dipyrone used as standard and with selective peripheral or central mechanism of action.     

Antiplatelet properties of novel N-substituted-phenyl-1,2,3-triazole-4-acylhydrazone derivatives

This paper describes the design, synthesis and pharmacological evaluation of new N-acylhydrazone (NAH) compounds, belonging to the N-substituted-phenyl-1,2,3-triazole-4-acylhydrazone class (2a-p). Classical heteroaromatic ring bioisosterism strategies were applied to the previously reported N-phenylpyrazolyl-4-acylhydrazone derivative 1, elected as lead-compound due to its important anti-aggregating profile on arachidonic acid induced platelet aggregation (IC(50)=24+/-0.5 micro M), from which emerge this new series 2. These new compounds 2a-p were readily synthesized, characterized and tested on platelet aggregation assays induced by collagen (5 micro g/mL), ADP (5 micro M) and arachidonic acid (100 micro M) in rabbit citrated platelet-rich plasma. Compounds 2b, 2d, and 2h were found to be the most potent, exhibiting a significant antiplatelet activity on arachidonic acid- and collagen-induced platelet aggregation. In addition, these new antiplatelet agents are free of gastric ulcerogenic effect and presented discrete anti-inflammatory and analgesic properties. The N-para-chlorophenyltriazolyl-4-acylhydrazone compound 2h produced the highest inhibitory effect on collagen (IC(50)=21.6+/-0.4 micro M) and arachidonic acid-induced platelet aggregation (IC(50)=2.2+/-0.06 micro M), suggesting that the nature of the substituent on the phenyl ring of the N-heteroaromatic system of NAH moiety may be an important structural requirement for the improvement of antiplatelet activity, in comparison with lead-series 1.     

Ontogenesis of the vitamin D receptor in rat heart

1,25-Dihydroxyvitamin D(3) through its receptor (vitamin D receptor; VDR) has important physiological effects such as calcium transport and cell growth and differentiation. Although the VDR is present in a variety of cell lines as well as in numerous tissues, including rat and human heart, no data are available about the presence of VDR in heart at different steps of rat life. In this study we evaluated the VDR expression using RT-PCR and immunohistochemical techniques in fetal (17, 18 and 20 gestational days), neonatal (4 and 8 days) and adult rat heart. Immunohistochemical techniques showed the VDR protein localisation in the nuclei of cardiac muscle fibres. Also, we demonstrated that VDR mRNA expression is changing over these different periods of development, showing significant differences in 20 days versus 18 days of fetal age. These changes in VDR expression may be related to other parameters associated with the development of the cardiac muscle and/or intracellular cardiac cell calcium homeostasis.