Triterpenoids as Novel Natural Inhibitors of Human Cathepsin L

Cathepsins L (catL) and B play an important role in tumor progression and have been considered promising therapeutic targets in the development of novel anticancer agents. Using a bioactivity‐guided fractionation, a series of triterpenoids was identified as a new class of competitive inhibitors towards cathepsin L with affinity values in micromolar range. Among the 14 compounds evaluated, the most promising were 3‐epiursolic acid ( 3 ), 3‐(hydroxyimino)oleanolic acid ( 9 ), and 3‐(hydroxyimino)masticadienoic acid ( 13 ) with IC₅₀ values of 6.5, 2.4, and 2.6 μM on catL, respectively. Most of the evaluated triterpenoids do not inhibit cathepsin B. Thus, the evaluated compounds exhibit a great potential to help in the design of new inhibitors with enhanced potency and affinity towards catL. Docking studies were performed in order to gain insight on the binding mode and SAR of these compounds.     

Gamma delta+ T cells involvement in viral immune control of chronic human herpesvirus 8 infection

Little is known about what effector populations are associated with the control of human herpesvirus 8 (HHV-8) infection in vivo. We compared T lymphocyte subsets among HIV-HHV-8+ and HIV-HHV-8- infected human individuals. alphabeta+ T cells from HHV-8-infected individuals displayed a significantly higher percentage of differentiated effector cells among both CD4+ and CD8+ T cell subsets. HHV-8 infection was associated with significant expansion of gammadelta+ Vdelta1 T cells expressing a differentiated effector cell phenotype in peripheral blood. In vitro stimulation of PBMC from HHV-8-infected individuals with either infectious viral particles or different HHV-8 viral proteins resulted in gammadelta Vdelta1 T cell activation. In addition, gammadelta Vdelta1 T cells displayed a strong reactivity against HHV-8-infected cell lines and prevented the release of infectious viral particles following the induction of lyric replication. These data indicate that gammadelta T cells play a role in both innate and adaptive T cell responses against HHV-8 in immunocompetent individuals.     

Contrasting Physiological Responses of Jatropha curcas Plants to Single and Combined Stresses of Salinity and Heat

In this study we evaluated the contrasting major physiological responses of Jatropha curcas L. to salinity alone and in combination with high temperature. The plants were subjected to salinity (100 mM NaCl) before and after exposure to 43 °C (heat stress) for 6 h. The effects of salinity were more harmful than heat stress, and the effects of salt stress were increased when both stress factors were combined. The negative effects of the combined treatments included strong impairment of the CO₂ assimilation rate and stomata conductance and increased Na⁺ and Cl^? accumulation in the leaves associated with increased membrane damage and lipid peroxidation. Heat favorably stimulated the accumulation of glycine betaine and chlorophyll in the salt-stressed leaves. Treatments with salt, heat, and their combination stimulated the antioxidant enzymatic defense system, that is, the expression of ascorbate peroxidase (APX) and superoxide dismutase (SOD), whereas the expression of catalase (CAT) was stimulated through treatments with salt alone and in combination with heat; treatment with heat alone did not affect CAT expression. The ascorbate redox state was decreased under salinity stress alone and in combination with heat but remained unaffected when treated with heat alone. Overall, the leaf H₂O₂ concentration did not change in response to these stresses, but lipid peroxidation and membrane damage was increased. Moreover, high temperature increases the negative effects of salt stress on key physiological processes, but treatment with heat alone is favorable for several metabolic indicators of young J. curcas plants. In contrast with heat, these plants exhibit higher physiological disturbances under isolated salinity stress.     

Alterations in the extracellular catabolism of nucleotides and platelet aggregation induced by high-fat diet in rats: effects of α-tocopherol

The aim of this study was to assess whether α-tocopherol administration prevented alterations in the ectonucleotidase activities and platelet aggregation induced by high-fat diet in rats. Thus, we examined four groups of male rats which received standard diet, high-fat diet (HFD), α-tocopherol (α-Toc), and high-fat diet plus α-tocopherol. HFD was administered ad libitum and α-Toc by gavage using a dose of 50 mg/kg. After 3 months of treatment, animals were submitted to euthanasia, and blood samples were collected for biochemical assays. Results demonstrate that NTPDase, ectonucleotide pyrophosphatase/phosphodiesterase, and 5′-nucleotidase activities were significantly decreased in platelets of HFD group, while that adenosine deaminase (ADA) activity was significantly increased in this group in comparison to the other groups (P?<?0.05). When rats that received HFD were treated with α-Toc, the activities of these enzymes were similar to the control, but ADA activity was significantly increased in relation to the control and α-Toc group (P?<?0.05). HFD group showed an increased in platelet aggregation in comparison to the other groups, and treatment with α-Toc significantly reduced platelet aggregation in this group. These findings demonstrated that HFD alters platelet aggregation and purinergic signaling in the platelets and that treatment with α-Toc was capable of modulating the adenine nucleotide hydrolysis in this experimental condition.     

Glutathionylation of Adenine Nucleotide Translocase Induced by Carbon Monoxide Prevents Mitochondrial Membrane Permeabilization and Apoptosis

The present work demonstrates the ability of CO to prevent apoptosis in a primary culture of astrocytes. For the first time, the antiapoptotic behavior can be clearly attributed to the inhibition of mitochondrial membrane permeabilization (MMP), a key event in the intrinsic apoptotic pathway. In isolated non-synaptic mitochondria, CO partially inhibits (i) loss of potential, (ii) the opening of a nonspecific pore through the inner membrane, (iii) swelling, and (iv) cytochrome c release, which are induced by calcium, diamide, or atractyloside (a ligand of ANT). CO directly modulates ANT function by enhancing ADP/ATP exchange and prevents its pore-forming activity. Additionally, CO induces reactive oxygen species (ROS) generation, and its prevention by β-carotene decreases CO cytoprotection in intact cells as well as in isolated mitochondria, revealing the key role of ROS. On the other hand, CO induces a slight increase in mitochondrial oxidized glutathione, which is essential for apoptosis modulation by (i) delaying astrocytic apoptosis, (ii) decreasing MMP, and (iii) enhancing ADP/ATP translocation activity of ANT. Moreover, CO and GSSG trigger ANT glutathionylation, a post-translational process regulating protein function in response to redox cellular changes. In conclusion, CO protects astrocytes from apoptosis by preventing MMP, acting on ANT (glutathionylation and inhibition of its pore activity) via a preconditioning-like process mediated by ROS and GSSG.     

Developmental mechanisms and experimental models to understand forebrain malformative diseases

The development of the central nervous system can be divided into a number of phases, each of which can be subject of genetic or epigenetic alterations that may originate particular developmental disorders. In recent years, much progress has been made in elucidating the molecular and cellular mechanisms by which the vertebrate forebrain develops. Therefore, our understanding of major developmental brain disorders such as cortical malformations and neuronal migration disorders has significantly increased. In this review, we will describe the major stages in forebrain morphogenesis and regionalization, with special emphasis on developmental molecular mechanisms derailing telencephalic development with subsequent damage to cortical function. Because animal models, mainly mouse, have been fundamental for this progress, we will also describe some characteristic mouse models that have been capital to explore these molecular mechanisms of malformative diseases of the human brain. Although most of the genes involved in the regulation of basic developmental processes are conserved among vertebrates, the extrapolation of mouse data to corresponding gene expression and function in humans needs careful individual analysis in each functional system.     

Antagonistic effect of Lactobacillus acidophilus, Saccharomyces boulardii and Escherichia coli combinations against experimental infections with Shigella flexneri and Salmonella enteritidis subsp. typhimurium in gnotobiotic mice

Lactobacillus acidophilus, Saccharomyces boulardii and Escherichia coli are probiotic strains used individually to protect against enteropathogenic agents. In order to determine if a synergistic effect of the individual protective mechanisms ordinarily attributed to each of these biotherapeutic agents is possible, we orally administered Lact. acidophilus H2B20, S. boulardii and E. coli EMO (LSE) to germfree mice. Ten days after colonization of the digestive tract, groups of animals associated (experimental) or not (control) with LSE were challenged orally with streptomycin resistant (Sfr) or streptomycin sensitive (Sfs) Shigella flexneri strains or Salmonella enteritidis subsp. typhimurium. Bacterial counts in faeces from experimental mice showed that the Sfr strain was eliminated 11 d after challenge while Sfs and S. enteritidis subsp. typhimurium colonized the digestive tract and continued to be present at high population levels (108 CFU g-1 of faeces), which is similar to that observed in control animals. All possible di- and monoassociations of the three probiotics with gnotobiotic mice were also performed before experimental oral infection with Sfr. The data showed that antagonism was obtained only when E. coli EMO was present. Different sensitivity of Sh. flexneri Sfr and Sfs to E. coli EMO antagonism could be explained by the different generation times between Sfr and Sfs, as shown by colonization kinetic experiments in the digestive tract of gnotobiotic mice.     

Age,Growth and Maturity of Red Porgy Pagrus pagrus (Sparidae) from Southeastern Brazil

Journal of Ichthyology - Age, growth and length-at-maturity of the red porgy Pagrus pagrus were studied off the southeastern coast of Brazil. A total of 798 otoliths from specimens sampled from the...