Marta Chagas Monteiro

Myotoxic phospholipases A2 isolated from Bothrops brazili snake venom and synthetic peptides derived from their C-terminal region: Cytotoxic effect on microorganism and tumor cells

This paper reports the purification and biochemical/pharmacological characterization of two myotoxic phospholipases A(2) (PLA(2)s) from Bothrops brazili venom, a native snake from Brazil. Both myotoxins (MTX-I and II) were purified by a single chromatographic step on a CM-Sepharose ion-exchange column up to a high purity level, showing M(r) approximately 14,000 for the monomer and 28,000Da for the dimer. The N-terminal and internal peptide amino acid sequences showed similarity with other myotoxic PLA(2)s from snake venoms, MTX-I belonging to Asp49 PLA(2) class, enzymatically active, and MTX-II to Lys49 PLA(2)s, catalytically inactive. Treatment of MTX-I with BPB and EDTA reduced drastically its PLA(2) and anticoagulant activities, corroborating the importance of residue His48 and Ca(2+) ions for the enzymatic catalysis. Both PLA(2)s induced myotoxic activity and dose-time dependent edema similar to other isolated snake venom toxins from Bothrops and Crotalus genus. The results also demonstrated that MTXs and cationic synthetic peptides derived from their 115-129 C-terminal region displayed cytotoxic activity on human T-cell leukemia (JURKAT) lines and microbicidal effects against Escherichia coli, Candida albicans and Leishmania sp. Thus, these PLA(2) proteins and C-terminal synthetic peptides present multifunctional properties that might be of interest in the development of therapeutic strategies against parasites, bacteria and cancer.

Immune modulation of some autoimmune diseases: the critical role of macrophages and neutrophils in the innate and adaptive immunity

Macrophages and neutrophils are key components involved in the regulation of numerous chronic inflammatory diseases, infectious disorders, and especially certain autoimmune disease. However, little is known regarding the contribution of these cells to the pathogenesis of autoimmune disorders. Recent studies have aimed to clarify certain important factors affecting the immunogenicity of these cells, including the type and dose of antigen, the microenvironment of the cell-antigen encounter, and the number, subset, and phenotype of these cells, which can prevent or induce autoimmune responses. This review highlights the role of macrophage subsets and neutrophils in injured tissues, supporting their cooperation during the pathogenesis of certain autoimmune diseases.

RETRACTED: Antiviral and antiparasite properties of an l-amino acid oxidase from the Snake Bothrops jararaca: Cloning and identification of a complete cDNA sequence

L-Amino acid oxidases (LAAOs, EC 1.4.3.2) are flavoenzymes that catalyze the stereospecific oxidative deamination of an L-amino acid substrate to the corresponding alpha-ketoacid with hydrogen peroxide and ammonia production. The present work describes the first report on the antiviral (Dengue virus) and antiprotozoal (trypanocidal and leishmanicide) activities of a Bothrops jararaca L-amino acid oxidase (BjarLAAO-I) and identify its cDNA sequence. Antiparasite effects were inhibited by catalase, suggesting that they are mediated by H2O2 production. Cells infected with DENV-3 virus previously treated with BjarLAAO-I, showed a decrease in viral titer (13-83-fold) when compared with cells infected with untreated viruses. Untreated and treated promastigotes (T. cruzi and L. amazonensis) were observed by transmission electron microscopy with different degrees of damage. Its complete cDNA sequence, with 1452 bp, encoded an open reading frame of 484 amino acid residues with a theoretical molecular weight and pI of 54,771.8 and 5.7, respectively. The cDNA-deduced amino acid sequence of BjarLAAO shows high identity to LAAOs from other snake venoms. Further investigations will be focused on the related molecular and functional correlation of these enzymes. Such a study should provide valuable information for the therapeutic development of new generations of microbicidal drugs.

Antifungal activity of some cyclooxygenase inhibitors on Candida albicans : PGE2-dependent mechanism

Candida spp., such as Candida albicans, are opportunisticyeasts that cause mucocutaneous and systemic infections withhighmortalityandmorbidityrates(Carrillo-Munozetal. 2006).Prostaglandins (PG) are small lipid molecules that havediverse biological activities, including the modulation of hostimmune responses. Both the host cells and fungal pathogenare sources of PG during fungal infection (Noverr et al. 2001,2002). These purified fungal PG, partially characterized as aprostaglandin E (PGE), enhance germ tube formation in C.albicans and down-modulate chemokine and tumor necrosisfactor alpha (TNF-α) production in mammalian cells (Noverret al. 2001). Since nonsteroidal anti-inflammatory drugs(NSAIDs) inhibit cyclooxygenase (COX) enzymes and reducethe synthesis of PG (Vane and Botting 1998), which arerequired for the development of yeast, NSAIDs may haveantifungal activity. Some studies have showed the role ofNSAIDs on fungal growth inhibitory effect, fungal PGE2production, and enzyme activation (Alem and Douglas2004; Erb-Downward and Noverr2007; Erb-Downward etal. 2008; Trofa et al.2009; Ells et al. 2011). In this work,we investigated whether some COX inhibitors couldinhibit the growth of C. albicans invitrobyaPGE2-dependent mechanism.Materials and methodsOrganism, drugs, and stock solution C. albicans strainATCC 40175 was obtained from the National Institute forHealth Quality Control, Brazil. Stock solutions of 2 mmol/Laspirin (acetylsalicylic acid, Sigma Aldrich), 4 mmol/Libuprofen (Sigma Aldrich), and 1 mmol/L indomethacin(SigmaAldrich)werepreparedin50%ethanol.Inaddition,astock solution of 220 mmol/L sodium salicylate (SigmaAldrich) was prepared in sterile distilled water. For theexperiments, COX inhibitors were used at final concen-trations ranging from 1.1–22 mmol/L. PGE2 (CaymanChemicals, Ann Arbor, MI, USA) was dissolved in 50%ethanol and used at a final concentration of 10 ng/mL.Drug treatment of yeast cells and colony counts The yeastinoculum preparation and in vitro antimicrobial drug screen-ing were performed byusing the broth microdilution method,as described by the Clinical and Laboratory StandardsInstitute (2008). Recent culture, in log phase, of C. albicanswas used to prepare the cell suspension adjusted to 0.5

Mast cell degranulation contributes to susceptibility to Leishmania major

Leishmaniasis causes high morbidity and mortality in tropical and subtropical areas. Mast cells can be activated by Leishmania or Leishmania products in vitro and in vivo. Several innate immunity mediators, including some released by mast cells, play roles in the outcome of the disease. In this study, we examined whether pharmacological inactivation of mast cells before infection with L. major interferes with the progressive disease in BALB/c mice. The results show that, when mast cells are degranulated before challenge with L. major, susceptible mice become more resistant to infection, as measured by decrease of lesion size and lower parasite loads. Mast cell degranulation reduced IL‐4 production. Moreover, mast cells degranulation enhanced mRNA expression for IFN‐γ, inducible nitric oxide, CCL2 and CCL5 in response to infection. Mast cell degranulation also decreased parasite loads in IL‐4 KO animals, indicating that mediators other than IL‐4 are involved in susceptibility in vivo. Taken together, our results disclose a role for mast cells in the induction of susceptibility to infection. This work contributes to a better understanding of the role of mast cells in Leishmania infection, and suggests a new field of study for strategies to contain the parasite, restricting its dissemination.

Action mechanism and cardiovascular effect of anthocyanins: a systematic review of animal and human studies

Cardiovascular diseases (CVD) are an important cause of death worldwide. Anthocyanins are a subgroup of flavonoids found in berries, flowers, fruits and leaves. In epidemiological and clinical studies, these polyphenols have been associated with improved cardiovascular risk profiles as well as decreased comorbidities. Human intervention studies using berries, vegetables, parts of plants and cereals (either fresh or as juice) or purified anthocyanin-rich extracts have demonstrated significant improvements in low density lipoproteins oxidation, lipid peroxidation, total plasma antioxidant capacity, and dyslipidemia as well as reduced levels of CVD molecular biomarkers. This review discusses the use of anthocyanins in animal models and their applications in human medicine, as dietary supplements or as new potent drugs against cardiovascular disease.

Effect of salivary gland extract of Leishmania vector, Lutzomyia longipalpis, on leukocyte migration in OVA-induced immune peritonitis

Salivary gland extracts (SGE) from Lutzomyia longipalpis potentate L. major infection by inducing a Th2 immune response. However, the effect of SGE on the effector phase of immune response is not known. Herein, we demonstrate that SGE inhibited neutrophil migration in ovalbumin (OVA)‐induced peritonitis in immunized mice. SGE pretreatment of mice inhibited OVA‐induced CD4+ and CD8+ T lymphocyte migration. The OVA‐induced production of TNF‐α, IL‐1β and leukotriene B4 (LTB4), neutrophil chemotactic mediators in this model, were inhibited by SGE. On the other hand, SGE enhanced production of IL‐10 and IL‐4. In naive mice, SGE also blocked LTB4‐induced neutrophil migration, but not that induced fMLP. Moreover, co‐incubation of LTB4 (but not fMLP, TNF‐α and MIP‐1α) with SGE inhibited the ability of LTB4 to induce neutrophil migration in vivo and in vitro. Altogether, the results suggest that SGE has anti‐inflammatory properties that are associated with inhibition of TNF‐α and LTB4 production and/or with the neutrophil chemotactic activity of LTB4. The effectiveness of SGE in inhibiting neutrophil migration and inflammatory mediators release in a Th1 immune inflammatory response model reinforces the need for isolation of the compounds responsible for these activities, which could be used as prototypes for the development new anti‐inflammatory drugs.

Spatial distribution of enteroparasites among school children from Guarapuava, State of Paraná, Brazil

The most common infections in human beings are caused by intestinal parasites. They can lead to a number of harmful effects, which could include, among others, intestinal obstruction, malnutrition, iron deficiency anemia, diarrhea, and poor absorption. In Brazil, enteroparasites are one of the main public health issues. The present study aims at analyzing the distribution and frequency of enteroparasite occurrence in 635 children from seven community schools in the city of Guarapuava, Parana (PR). In addition, we used similarity and diversity indices to analyze the parasite community. We found 475 samples with at least one parasite showing that 75.27% of children had enteroparasites. A smaller fraction (26.73%) of children harbored several parasites (multiparasitism), especially Giardia duodenalis (56%), and Ascaris lumbricoides (18%). Statistical analysis showed that three (out of seven) children communities had higher similarity in frequency and amount of parasites. Our results suggest that the children studied were highly infected by enteroparasites. These levels of infestation could be related to several factors, such as climate, social and economic conditions and characteristics of the parasites.

In Vitro Protective Effect and Antioxidant Mechanism of Resveratrol Induced by Dapsone Hydroxylamine in Human Cells

Dapsone (DDS) hydroxylamine metabolites cause oxidative stress- linked adverse effects in patients, such as methemoglobin formation and DNA damage. This study evaluated the ameliorating effect of the antioxidant resveratrol (RSV) on DDS hydroxylamine (DDS-NHOH) mediated toxicity in vitro using human erythrocytes and lymphocytes. The antioxidant mechanism was also studied using in-silico methods. In addition, RSV provided intracellular protection by inhibiting DNA damage in human lymphocytes induced by DDS-NHOH. However, whilst pretreatment with RSV (10–1000 μM significantly attenuated DDS-NHOH-induced methemoglobinemia, but it was not only significantly less effective than methylene blue (MET), but also post-treatment with RSV did not reverse methemoglobin formation, contrarily to that observed with MET. DDS-NHOH inhibited catalase (CAT) activity and reactive oxygen species (ROS) generation, but did not alter superoxide dismutase (SOD) activity in erythrocytes. Pretreatment with RSV did not alter these antioxidant enzymes activities in erythrocytes treated with DDS-NHOH. Theoretical calculations using density functional theory methods showed that DDS-NHOH has a pro-oxidant effect, whereas RSV and MET have antioxidant effect on ROS. The effect on methemoglobinemia reversion for MET was significantly higher than that of RSV. These data suggest that the pretreatment with resveratrol may decrease heme-iron oxidation and DNA damage through reduction of ROS generated in cells during DDS therapy.

Pharmacological Perspectives of Wasp Venom

Venoms of several animals have been used to study various physiopathologic processes, and also to offer opportunity to design and develop new therapeutic drugs. We briefly review certain wasp venom components and their biological effects, which may be potential sources of novel pharmacologically active compounds.