Isolation, functional, and partial biochemical characterization of galatrox, an acidic lectin from Bothrops atrox snake venom

A rational in silico approach to identify inhibitors of Batroxrhagin from Bothrops atrox

Bothrops atrox venom comprises several types of bioactive molecules, enzymatic and non-enzymatic, among those, Batroxrhagin is the most predominant SVMP P-III enzyme, which are responsible for induction of local and systemic hemorrhage and muscle fibers damage, impairing regeneration. Due to great difficulties in establishing an antibothropic drug, new strategies must be addressed to achieve a more effective and efficient treatment. There are no studies of specific catalytic inhibitors of Batroxrhagin. However, there are in vitro studies that have described similar metalloprotease inhibitors. The inhibitor batimastat was used as a leading compound for the search and selection of similar candidates. This molecule is widely cited as a metalloprotease inhibitor and as an antimetastatic. In addition to batimastat-like molecules, four other reported metalloprotease inhibitors were included to compose the study's positive control group. Hence, 580 molecules were tested. The three-dimensional structure of B. atrox Batroxrhagin was predicted based on homologous structures using Modeller 9.20. Molecular docking calculation was performed using Autodock 4.2 and molecular surfaces and interactions were analyzed using Biovia/Discovery Studio 2017. Among 576 molecules, 42 similar to batismast resulted in a better energy of interaction than all positive controls, including batimastat itself. The batimastat-like molecules with lowest energy and positive controls were subjected to molecular dynamics for 30 ns in Gromacs 2019.4. This batimastat-like molecule produced better stability among all the Batroxrhagin-ligand complexes analyzed. Overall, the proposed compounds present justifiable evidence for future in vitro tests aiming to inhibit Batroxrhagin. Communicated by Ramaswamy H. Sarma.

Separation and Analytical Techniques Used in Snake Venomics: A Review Article

The deleterious consequences of snake envenomation are due to the extreme protein complexity of snake venoms. Therefore, the identification of their components is crucial for understanding the clinical manifestations of envenomation pathophysiology and for the development of effective antivenoms. In addition, snake venoms are considered as libraries of bioactive molecules that can be used to develop innovative drugs. Numerous separation and analytical techniques are combined to study snake venom composition including chromatographic techniques such as size exclusion and RP-HPLC and electrophoretic techniques. Herein, we present in detail these existing techniques and their applications in snake venom research. In the first part, we discuss the different possible technical combinations that could be used to isolate and purify SV proteins using what is known as bioassay-guided fractionation. In the second part, we describe four different proteomic strategies that could be applied for venomics studies to evaluate whole venom composition, including the mostly used technique: RP-HPLC. Eventually, we show that to date, there is no standard technique used for the separation of all snake venoms. Thus, different combinations might be developed, taking into consideration the main objective of the study, the available resources, and the properties of the target molecules to be isolated.

Bothrops jararacussu snake venom lectin induces mast cell activation and vascular permeability enhance in an animal model

Bothrops species trigger an acute inflammatory response in victims, with activated leukocytes releasing several mediators that may contribute to local and systemic effects. The effects of BjcuL, a lectin isolated from B. jararacussu snake venom, on mast cells and vasopermeability were investigated in this study. BjcuL activates mast cells and increases vasopermeability through the involvement of histamine and platelet activating factor, which may play a role in the victims' acute inflammatory reaction.

Bothrops atrox, the most important snake involved in human envenomings in the amazon: How venomics contributes to the knowledge of snake biology and clinical toxinology

Bothrops atrox snakes are mostly endemic of the Amazon rainforest and is certainly the South American pit viper responsible for most of the snakebites in the region. The composition of B. atrox venom is significantly known and has been used to trace the relevance of the venom phenotype for snake biology and for the impacts in the clinics of human patients involved in accidents by B. atrox. However, in spite of the wide distribution and the great medical relevance of B. atrox snakes, B. atrox taxonomy is not fully resolved and the impacts of the lack of taxonomic resolution on the studies focused on venom or envenoming are currently unknown. B. atrox venom presents different degrees of compositional variability and is generally coagulotoxic, inducing systemic hematological disturbances and local tissue damage in snakebite patients. Antivenoms are the effective therapy for attenuating the clinical signs. This review brings a comprehensive discussion of the literature concerning B. atrox snakes encompassing from snake taxonomy, diet and venom composition, towards clinical aspects of snakebite patients and efficacy of the antivenoms. This discussion is highly supported by the contributions that venomics and antivenomics added for the advancement of knowledge of B. atrox snakes, their venoms and the treatment of accidents they evoke.

Inflammation and coagulation crosstalk induced by BJcuL, a galactose-binding lectin isolated from Bothrops jararacussu snake venom

Inflammation and coagulopathies are important systemic events following snakebite. Snake venom galactoside-binding lectins (SVgalLs) are known modulators of the immune response with no direct effect on hemostasis. Considering the crosstalk between inflammation and coagulation, the present study investigated how BJcuL, a proinflammatory SVgalL isolated from Bothrops jararacussu venom, mediated the inflammation-induced procoagulant activity. We examined the proinflammatory cytokine production and procoagulant tissue factor (TF) activity in human whole blood and monocyte-rich cell suspension (MR-PBMC) treated with BJcuL. This lectin increased production of the cytokines TNF-α, IL-1β and IL-6, upregulated TF expression on the cell surface, and induced procoagulant activity. The proinflammatory behavior was mediated by the direct interaction between the lectin and toll-like receptor 4, via binding to β-galactoside-containing glycoconjugates on the cell surface, and activation of NFκ-B signaling. Interestingly, the BJcuL-induced inflammation was directly associated with the procoagulant activity of MR-PBMC cells. In whole blood culture, the lectin exhibited similar behavior, i.e. it induced cytokine production and MR-PBMC TF-mediated procoagulant activity. Therefore, the present study is the first report on the inflammation-induced procoagulant activity of SVgalLs, and it indicates that BJcuL is an important factor associated with coagulopathy in patients with snake envenomation.

Sacha inchi seeds from sub-tropical cultivation: effects of roasting on antinutrients, antioxidant capacity and oxidative stability

Due to the strong bitter taste, sacha inchi seeds are usually consumed after roasting, which also contributes to the elimination of antinutrients. Sacha inchi plants fully adapted to cultivation under sub-tropical climate conditions were produced in southeastern Brazil. Our main goal was to evaluate the effect of dry heating (roasting) on the antinutrient content of these seeds. We also investigated the effects of the applied roasting treatments on the antioxidant activity, proximate composition and oxidative stability of the seeds. To the best of our knowledge, this is the first report on antinutrients of sacha inchi seeds cultivated under sub-tropical conditions, outside their native tropical environment. Except for saponins, which are not heat-labile compounds, the contents of all assessed antinutrients continually reduced with the increase in roasting temperature. Roasting improved antioxidant activity and phenolic content in the seeds at the highest temperature. Oxidation changes occurred in the seed oil, and they increased with temperature. However, maximum peroxide value was within the acceptable consumption limits. As a conclusion, roasting treatments can be applied to minimize the antinutrient potential in sacha inchi seeds. Knowledge on the composition and proper processing of sacha inchi cultivated under sub-tropical conditions may support future efforts focused on the development of new production areas.

Snake venom galactoside-binding lectins: a structural and functional overview

Snake venom galactoside-binding lectins (SVgalLs) comprise a class of toxins capable of recognizing and interacting with terminal galactoside residues of glycans. In the past 35 years, since the first report on the purification of thrombolectin from Bothrops atrox snake venom, several SVgalLs from Viperidae and Elapidae snake families have been described, as has progressive improvement in the investigation of structural/functional aspects of these lectins. Moreover, the advances of techniques applied in protein-carbohydrate recognition have provided important approaches in order to screen for possible biological targets. The present review describes the efforts over the past 35 years to elucidate SVgalLs, highlighting their structure and carbohydrate recognition function involved in envenomation pathophysiology and potential biomedical applications.

Galatrox is a C-type lectin in Bothrops atrox snake venom that selectively binds LacNAc-terminated glycans and can induce acute inflammation

Previous studies indicate that snake venom contains glycan-binding proteins (GBPs), although the binding specificity and biological activities of many of these GBPs is unclear. Here we report our studies on the glycan binding specificity and activities of galatrox, a Bothrops atrox snake venom-derived GBP. Glycan microarray analysis indicates that galatrox binds most strongly to glycans expressing N-acetyllactosamine (LacNAc), with a significant preference for Galβ1-4GlcNAcβ over Galβ1-3GlcNAcβ compounds. Galatrox also bound immobilized laminin, a LacNAc-dense extracellular matrix component, suggesting that this GBP can bind LacNAc-bearing glycoproteins. As several endogenous mammalian GBPs utilize a similar binding LacNAc binding preference to regulate neutrophil and monocyte activity, we hypothesized that galatrox may mediate B. atrox toxicity through regulation of leukocyte activity. Indeed, galatrox bound neutrophils and promoted leukocyte chemotaxis in a carbohydrate-dependent manner. Similarly, galatrox administration into the mouse peritoneal cavity induced significant neutrophil migration and the release of pro-inflammatory cytokines IL-1α and IL-6. Exposure of bone marrow-derived macrophages to galatrox induced generation of pro-inflammatory mediators IL-6, TNF-α, and keratinocyte-derived chemokine. This signaling by galatrox was mediated via its carbohydrate recognition domain by activation of the TLR4-mediated MyD88-dependent signaling pathway. These results indicate that galatrox has pro-inflammatory activity through its interaction with LacNAc-bearing glycans on neutrophils, macrophages and extracellular matrix proteins and induce the release of pro-inflammatory mediators.

Pharmaceutical and biomedical applications of affinity chromatography: recent trends and developments

Affinity chromatography is a separation technique that has become increasingly important in work with biological samples and pharmaceutical agents. This method is based on the use of a biologically related agent as a stationary phase to selectively retain analytes or to study biological interactions. This review discusses the basic principles behind affinity chromatography and examines recent developments that have occurred in the use of this method for biomedical and pharmaceutical analysis. Techniques based on traditional affinity supports are discussed, but an emphasis is placed on methods in which affinity columns are used as part of HPLC systems or in combination with other analytical methods. General formats for affinity chromatography that are considered include step elution schemes, weak affinity chromatography, affinity extraction and affinity depletion. Specific separation techniques that are examined include lectin affinity chromatography, boronate affinity chromatography, immunoaffinity chromatography, and immobilized metal ion affinity chromatography. Approaches for the study of biological interactions by affinity chromatography are also presented, such as the measurement of equilibrium constants, rate constants, or competition and displacement effects. In addition, related developments in the use of immobilized enzyme reactors, molecularly imprinted polymers, dye ligands and aptamers are briefly considered.