Lysophosphatidylcholine produced by the phospholipase A2 isolated from Lachesis muta snake venom modulates natural killer activity as a protein kinase C effector

The Colombian bushmasters Lachesis acrochorda (García, 1896) and Lachesis muta (Linnaeus, 1766): Snake species, venoms, envenomation, and its management

In Colombia, there are two species of bushmaster snakes, Lachesis acrochorda, which is distributed mainly in the west of the country (in the Choco region), and Lachesis muta in the southeast (in the Amazon and Orinoquia region), whose presence has been reduced due to the destruction of their habitats. Captive maintenance is challenging, making it difficult to obtain their venom for study and antivenom manufacturing. They are the largest vipers in the world. The occurrence of human envenomation is quite rare, but when it occurs, it is associated with high mortality. Bushmaster venom is necrotizing, hemorrhagic, myotoxic, hemolytic, and cardiovascular depressant. Due to the presence of bradycardia, hypotension, emesis, and diarrhea in some patients (Lachesis syndrome), the possibility of a vagal or cholinergic effect is raised. The treatment of envenomation is hindered by the scarcity of antivenom and the need to use high doses. A review of the most relevant biological and medical aspects of bushmaster snakes is presented, mainly for those occurring in Colombia, to facilitate their recognition and raise awareness about the need for special attention to improve their conservation and advance scientific knowledge, in particular, about their venom.

Immunomodulatory properties of molecules from animal venoms

The immune system can amplify or decrease the strength of its response when it is stimulated by chemical or biological substances that act as immunostimulators, immunosuppressants, or immunoadjuvants. Immunomodulation is a progressive approach to treat a diversity of pathologies with promising results, including autoimmune disorders and cancer. Animal venoms are a mixture of chemical compounds that include proteins, peptides, amines, salts, polypeptides, enzymes, among others, which produce the toxic effect. Since the discovery of captopril in the early 1980s, other components from snakes, spiders, scorpions, and marine animal venoms have been demonstrated to be useful for treating several human diseases. The valuable progress in fields such as venomics, molecular biology, biotechnology, immunology, and others has been crucial to understanding the interaction of toxins with the immune system and its application on immune pathologies. More in-depth knowledge of venoms' components and multi-disciplinary studies could facilitate their transformation into effective novel immunotherapies. This review addresses advances and research of molecules from venoms that have immunomodulatory properties.

Metabolomics Study of the Biochemical Changes in the Plasma of Myocardial Infarction Patients

Myocardial infarction (MI) is a common and multifactorial disease that has the highest morbidity and mortality in the world. Although a number of physiological, pathological, and functional parameters have been investigated, only scarce information regarding the changes of small metabolites in the plasma has been reported, and this lack of information may cause poor MI diagnosis and treatment. In the present study, we aimed to investigate the metabolic profiles of plasma samples from MI patients to identify potential disease biomarkers and to study the pathology of MI. Metabolic profiles of the plasma of 30 MI patients and 30 controls were obtained using ultra-performance liquid chromatography/electrospray ionization quadruple time-of-flight mass spectrometry. The resulting data were processed using pattern recognition approaches, including principal component analysis and partial least squares-discriminant analysis, to identify the metabolites that differed between the groups. Significant differences in the plasma levels of the following 10 metabolites were observed in the MI patients compared with the controls: phosphatidylserine, C16-sphingosine, N-methyl arachidonic amide, N-(2-methoxyethyl) arachidonic amide, linoleamidoglycerophosphate choline, lyso-PC (C18:2), lyso-PC (C16:0), lyso-PC (C18:1), arachidonic acid, and linoleic acid. The changes in these 10 biomarkers indicated perturbations of energy metabolism, phospholipid metabolism, and fatty acid metabolism in the MI patients. These findings hold promise to advance the treatment, diagnosis, and prevention of MI.

PKCζ phosphorylates TRAF2 to protect against intestinal ischemia-reperfusion-induced injury

Intestinal ischemia-reperfusion (I/R) is a common clinical problem that occurs during various clinical pathological processes. Excessive apoptosis has an indispensable role in intestinal I/R injury. Tumor necrosis factor receptor-associated factor 2 (TRAF2) and PKCζ have an essential role in apoptosis. Here, we aimed to investigate the effects of PKCζ and TRAF2 and to explore the correlation between PKCζ and TRAF2 in intestinal I/R injury. Mice were subjected to intestinal I/R injury in vivo. In vitro experiments were conducted by treating Caco-2 cells with hypoxia/reoxygenation (H/R) stimulation to simulate intestinal I/R. Intestinal tissue samples and Caco-2 cells were examined using various approaches. Intestinal I/R induced the membrane translocation and phosphorylation of PKCζ. Pretreatment with the PKCζ activator phosphatidylcholine remarkably attenuated gut injury by suppressing apoptosis. H/R induced PKCζ to combine with TRAF2, which was phosphorylated by PKCζ at Ser⁵⁵, but not at Ser¹¹, under intestinal I/R or H/R conditions. In addition, TRAF2 Ser⁵⁵ phosphorylation increased cell survival by inhibiting cell apoptosis in the H/R model. Mechanistically, TRAF2 Ser⁵⁵ phosphorylation promoted NF-κB activation but suppressed c-Jun activation in Caco-2 cells under H/R conditions. The results of this study demonstrate that the PKCζ/TRAF2 pathway represents a novel protective mechanism against intestinal I/R injury. Therefore, the PKCζ/TRAF2 pathway is a novel target for potential treatments of intestinal I/R injury-related diseases.

Research on the Relationships between Endogenous Biomarkers and Exogenous Toxic Substances of Acute Toxicity in Radix Aconiti

Radix Aconiti, a classic traditional Chinese medicine (TCM), has been widely used throughout China for disease treatment due to its various pharmacological activities, such as anti-inflammatory, cardiotonic, and analgesic effects. However, improper use of Radix Aconiti often generated severe acute toxicity. Currently, research on the toxic substances of Radix Aconiti is not rare. In our previous study, acute toxic biomarkers of Radix Aconiti have been found. However, few studies were available to find the relationships between these endogenous biomarkers and exogenous toxic substances. Therefore, in this study, toxic substances of Radix Aconiti have been found using UPLC-Q-TOF-MS technology. Then, we used biochemical indicators as a bridge to find the relationships between biomarkers and toxic substances of Radix Aconiti through Pearson correlation analysis and canonical correlation analysis (CCA). Finally, the CCA results showed that LysoPC(22:5) is related to 14-acetyl-talatisamine, mesaconitine, talatisamine and deoxyaconitine in varying degrees; l-acetylcarnitine is negatively correlated with deoxyaconitine and demethyl-14-acetylkaracoline; shikimic acid has a good correlation with karacoline, demethyl-14-acetylkaracoline and deoxyaconitine; and valine is correlated with talatisamine and deoxyaconitine. Research on these relationships provides an innovative way to interpret the toxic mechanism of traditional Chinese medicine, and plays a positive role in the overall study of TCM toxicity.

Standardized Chinese Formula Xin-Ke-Shu inhibits the myocardium Ca(2+) overloading and metabolic alternations in isoproterenol-induced myocardial infarction rats

Xin-Ke-Shu (XKS) is a traditional Chinese patent medicine used for treatment of coronary heart diseases in China. However, its mechanism of action is still unclear. In this paper, the mediation of XKS on the isoproterenol (ISO)-induced myocardial infarction (MI) rat were evaluated based on a tissue-targeted metabonomics in vitro/vivo. The result indicated that twelve metabolic pathways were involved in the therapeutic effect of XKS in vivo, where seven pathways were associated with the Ca²⁺ overloading mechanism. In agreement with regulation on metabolic variations, XKS markedly reversed the over-expressions of three involved proteins including phospholipase A2 IIA (PLA2 IIA), calcium/calmodulin-dependent protein kinase II (CaMK II) and Pro-Caspase-3. The metabolic regulations of XKS on H9c2 cell also partially confirmed its metabolic effect. These metabolic characteristics in vitro/vivo and western blotting analysis suggested that XKS protected from MI metabolic perturbation major via inhibition of Ca²⁺ overloading mechanism. Furthermore, 11 active ingredients of XKS exerted steady affinity with the three proteins through the molecular docking study. Our findings indicate that the metabonomics in vitro/vivo combined with western blotting analysis offers the opportunity to gain insight into the comprehensive efficacy of TCMs on the whole metabolic network.

Experimental Lachesis muta rhombeata envenomation and effects of soursop (Annona muricata) as natural antivenom

Background

In the Atlantic forest of the North and Northeast regions of Brazil, local population often uses the fruit juice and the aqueous extract of leaves of soursop (Annona muricata L.) to treat Lachesis muta rhombeata envenomation. Envenomation is a relevant health issue in these areas, especially due to its severity and because the production and distribution of antivenom is limited in these regions. The aim of the present study was to evaluate the relevance of the use of soursop leaf extract and its juice against envenomation by Lachesis muta rhombeata.

Methods

We evaluated the biochemical, hematological and hemostatic parameters, the blood pressure, the inflammation process and the lethality induced by Lachesis muta rhombeata snake venom. We also assessed the action of the aqueous extract of leaves (AmL) and juice (AmJ) from A. muricata on the animal organism injected with L. m. rhombeata venom (LmrV) in the laboratory environment.

Results

LmrV induced a decrease of total protein, albumin and glucose; and increase of creatine kinase, aspartate aminotransferase, and urea concentrations. It provoked hemoconcentration followed by reduction of hematocrit, an increase in prothrombin time and partial thromboplastin time and a decrease of the blood pressure. LmrV induced the release of interleukin-6, an increase in neutrophils and changes in the serum protein profile, characteristic of the acute inflammatory process. LD₅₀ values were similar for the groups injected with LmrV and treated or untreated with AmJ and AmL. Both treatments play a role on the maintenance of blood glucose, urea and coagulation parameters and exert a protective action against the myotoxicity. However, they seem to worsen the hypotension caused by LmrV.

Conclusion

The treatments with AmJ and AmL present some beneficial actions, but they might intensify some effects of the venom. Therefore, additional studies on A. muricata are necessary to enable its use as natural antivenom for bushmaster snakebite.

Here, There, and Everywhere: The Ubiquitous Distribution of the Immunosignaling Molecule Lysophosphatidylcholine and Its Role on Chagas Disease

Chagas disease is a severe illness, which can lead to death if the patients are not promptly treated. The disease is caused by the protozoan parasite Trypanosoma cruzi, which is mostly transmitted by a triatomine insect vector. There are 8-10 million people infected with T. cruzi in the world, but the transmission of such disease by bugs occurs only in the Americas, especially Latin America. Chronically infected patients will develop cardiac diseases (30%) and up digestive, neurological, or mixed disorders (10%). Lysophosphatidylcholine (LPC) is the major phospholipid component of oxidized low-density lipoproteins associated with atherosclerosis-related tissue damage. Insect-derived LPC powerfully attracts inflammatory cells to the site of the insect bite, enhances parasite invasion, and inhibits the production of nitric oxide by T. cruzi-stimulated macrophages. The recognition of the ubiquitous presence of LPC on the vector saliva, its production by the parasite itself and its presence both on patient plasma and its role on diverse host × parasite interaction systems lead us to compare its distribution in nature with the title of the famous Beatles song "Here, There and Everywhere" recorded exactly 50 years ago in 1966. Here, we review the major findings pointing out the role of such molecule as an immunosignaling modulator of Chagas disease transmission. Also, we believe that future investigation of the connection of this ubiquity and the immune role of such molecule may lead in the future to novel methods to control parasite transmission, infection, and pathogenesis.

Screening, verification, and optimization of biomarkers for early prediction of cardiotoxicity based on metabolomics

Drug-induced cardiotoxicity seriously affects human health and drug development. However, many conventional detection indicators of cardiotoxicity exhibit significant changes only after the occurrence of severe heart injuries. Therefore, we investigated more sensitive and reliable indicators for the evaluation and prediction of cardiotoxicity. We created rat cardiotoxicity models in which the toxicity was caused by doxorubicin (20 mg/kg), isoproterenol (5 mg/kg), and 5-fluorouracil (125 mg/kg). We collected data from rat plasma samples based on metabolomics using ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry. Following multivariate statistical and integration analyses, we selected 39 biomarker ions of cardiotoxicity that predict cardiotoxicity earlier than biochemical analysis and histopathological assessment. Because drugs with different toxicities may cause similar metabolic changes compared with other noncardiotoxic models (hepatotoxic and nephrotoxic models), we obtained 10 highly specific biomarkers of cardiotoxicity. We subsequently used a support vector machine (SVM) to develop a predictive model to verify and optimize the exclusive biomarkers. l-Carnitine, 19-hydroxydeoxycorticosterone, LPC (14:0), and LPC (20:2) exhibited the strongest specificities. The prediction rate of the SVM model is as high as 90.0%. This research provides a better understanding of drug-induced cardiotoxicity in drug safety evaluations and secondary development and demonstrates novel ideas for verification and optimization of biomarkers via metabolomics.

The red seaweed Plocamium brasiliense shows anti-snake venom toxic effects

BACKGROUND

Snakebite is considered a neglected tropical disease by the World Health Organization. In Brazil, about 70% of the envenomation cases are caused by Bothrops snakes. Its venom may provoke hemorrhage, pain, necrosis, hemolysis, renal or cardiac failure and even death in victims. Since commercial antivenom does not efficiently neutralize the local toxic effects of venoms, natural products have been tested in order to provide alternative or complementary treatment to serum therapy. Therefore, the present study aimed to evaluate the ability of the seaweed Plocamium brasiliense and its active derivatives to neutralize hemorrhagic, edematogenic, hemolytic, coagulant and proteolytic activities of B. jararaca venom.

METHODS

Specimens of P. brasiliense were collected in Rio de Janeiro state, Brazil, dried and submitted to oil extraction using four solvents of increasing polarities, n-hexane (HEX), dichloromethane (DCM), ethyl acetate (ETA) and hydroalcoholic solution (HYD). The solvents were evaporated, yielding HEX, DCM, ETA and HYD extracts. Further, all extracts were dissolved in dimethylsulfoxide. In addition, two monoterpenes (8-bromo-3,4,7-trichloro-3,7-dimethyl-1E, 5E-octadiene and 1,8-dibromo-3,4,7-trichloro-3,7-dimethyl-1E, 5E-octadiene) and a cholesterol fraction were isolated from the extract of P. brasiliense prepared in hexane. Algal samples were incubated for 30 minutes with B. jararaca venom, and then tested for lethality; hemorrhagic, edematogenic, hemolytic, coagulant and proteolytic effects.

RESULTS

Most of the algal extracts inhibited the toxic effects with different potencies. The DCM extract was the most effective, since it inhibited all types of toxic activity. On the other hand, the HYD extract failed to inhibit any effect. Moreover, the isolated products inhibited proteolysis and protected mice from hemorrhage in 30% of the cases, whereas 8-bromo-3,4,7-trichloro-3,7-dimethyl-1E, 5E-octadiene inhibited 100% and 20% of the hemorrhagic and proteolytic activities, respectively. None of the algal products were toxic to mice.

CONCLUSION

Seaweeds may be a promising source of inhibitors against toxic effects caused by B. jararaca envenomation, which may contribute to antivenom treatment.

Pattern of inflammatory response to Loxosceles intermedia venom in distinct mouse strains: a key element to understand skin lesions and dermonecrosis by poisoning

Envenomation caused by spiders Loxosceles induce intense dermonecrosis at the bite site and systemic disease. In this work we described the hyaluronidase and collagenase activities in vitro of the Loxosceles intermedia venom, but no phospholipase A2 activity. In vivo, we evaluated the effect of L. intermedia venom used different strain of mice, C57BL/6, BALB/c and Swiss. All mice developed paw edema after venom injection, persistent for 24 h in BALB/c and C57BL/6 mice. Histopathological analysis of the skin after venom injection revealed vascular congestion in Swiss mice and an inflammatory reaction in BALB/c and C57BL/6 mice. The mobilization of inflammatory cells from bone marrow, spleen and blood was investigated. Typical innate immune response with mobilization of myeloid cells and cytotoxic CD8 T lymphocytes was observed in C57BL/6 mice. In contrast, typical acquired/humoral immune response was observed in BALB/c mice, with preferential involvement of conventional B lymphocytes and CD4 T helper cells. The skin inflammation associated to mobilization of inflammatory cells indicated that mice models are strongly recommended to investigate specific cell types involved with immune response to the envenomation and mechanisms to inhibit skin lesions.

Effects of oligoelements Se, Zn, and Mn plus Lachesis muta venom in experimental scleroderma

Scleroderma, sclerosis of the skin, is a severe autoimmune disease refractant to all kind of treatments. To study the in vivo effects of a combination of three oligoelements selenium (Se), zinc (Zn), and manganese (Mn) plus Lachesis muta venom (O-LM) on the bleomycin (BLM)-induced scleroderma mouse experimental model. C3H mice were randomly divided into four groups: control (phosphate-buffered saline (PBS)), O-LM, BLM, and BLM + O-LM. All administrations were performed subcutaneously into the back of mice. BLM was injected 5 days per week for three consecutive weeks and O-LM was administered simultaneously with BLM from the beginning of the experiments and lasted for 3 weeks after the final BLM or PBS injection (for O-LM and BLM + O-LM groups), when animals were sacrificed and histopathological, immunohistochemical, thiobarbituric acid reactive species (TBARS) evaluation, and autoantibodies detection were determined. O-LM significantly reduced BLM-induced enhanced dermal thickness (605 ± 47 vs. 956 ± 59 μm, P < 0.01), collagen deposition, and mast cells infiltration (43.1 ± 1.0 vs. 102 ± 14.1 mast cells, P < 0.05). O-LM administration significantly blocked BLM-induced oxidative damage and the enhanced immunoreactive fibroblasts for α-smooth muscle actin while reduced BLM-induced autoantibodies that strongly react mainly with skin and spleen. O-LM significantly reduced BLM-induced scleroderma through the modulation of antioxidant and immunological pathways.

In vitro comparison of enzymatic effects among Brazilian Bothrops spp. venoms

In various types of snake venom, the major toxic components are proteinases and members of the phospholipase A2 family, although other enzymes also contribute to the toxicity. In this study, we evaluated the proteolytic, phospholipase, and L-Amino acid oxidase activities in the venom of five Bothrops species-Bothrops jararaca, Bothrops jararacussu, Bothrops moojeni, Bothrops neuwiedi, and Bothrops alternatus-all of which are used in the production of commercial antivenom, prepared in horses. The enzymatic activities of each species' venom were classified as high, moderate, or low. B. moojeni venom demonstrated the highest enzymatic activity profile, followed by the venom of B. neuwiedi, B. jararacussu, B. jararaca, and B. alternatus. To our knowledge, this is the first study to compare all of these enzymes from multiple species, which is significant in view of the activity of L-amino acid oxidase across Bothrops species.

A phospholipase A₂ isolated from Lachesis muta snake venom increases the survival of retinal ganglion cells in vitro

We have previously showed that a phospholipase A₂ isolated from Lachesis muta snake venom and named LM-PLA₂-I displayed particular biological activities, as hemolysis, inhibition on platelet aggregation, edema induction and myotoxicity. In the present work, we evaluated the effect of LM-PLA₂-I on the survival of axotomized rat retinal ganglion cells kept in vitro, as well as its mechanism of action. Our results clearly showed that treatment with LM-PLA₂-I increased the survival of ganglion cells (100% when compared to control cultures) and the treatment of LM-PLA₂-I with p-bromophenacyl bromide abolished this effect. This result indicates that the effect of LM-PLA₂-I on ganglion cell survival is entirely dependent on its enzymatic activity and the generation of lysophosphatidylcholine (LPC) may be a prerequisite to the observed survival. In fact, commercial LPC mimicked the effect of LM-PLA₂-I upon ganglion cell survival. To investigate the mechanism of action of LM-PLA₂-I, cultures were treated with chelerythrine chloride, BAPTA-AM, rottlerin and also with an inhibitor of c-junc kinase (JNKi). Our results showed that rottlerin and JNK inhibitor abolished the LM-PLA₂-I on ganglion cell survival. Taken together, our results showed that LM-PLA₂-I and its enzymatic product, LPC promoted survival of retinal ganglion cells through the protein kinase C pathway and strongly suggest a possible role of the PLA₂ enzyme and LPC in controlling the survival of axotomized neuronal cells.

Radioprotection of sensitive rat tissues by oligoelements Se, Zn, Mn plus Lachesis muta venom

In this study we first evaluated the general radioprotective efficacy of Se, Zn and Mn (4 µg/ml each) plus Lachesis muta venom (4 ng/ml) combination (O-LM) by determining survival on rats irradiated with lethal doses of gamma-rays. The aim of the second part of the study was to investigate the O-LM ability to prevent ionizing radiation-induced damage on small intestine, bone marrow and submandibular glands. Hence, histological characteristics and functional studies, together with proliferation and apoptotic marker levels on whole body irradiated rats with a 5 Gy dose were evaluated. Results show that all animals of the untreated group died after whole body irradiation with 8 and 10 Gy while 60 day-survival was more than 80% and 40% in O-LM-treated animals, respectively. Histopathological examinations revealed a high degree of small intestine and submandibular gland radioprotection 3 days post-irradiation. O-LM inhibited histological damage on small intestine, restoring the radiation-induced reduction in villous height and crypt number. O-LM prevented radiation-induced loss of salivary gland function and morphological alterations. These effects were associated to a complete inhibition of radiation-induced apoptosis. Furthermore, studies performed 30 days post-irradiation revealed that O-LM significantly improved bone marrow repopulation, increasing all medullar progenies to the extent of the non-irradiated animals, and completely prevented permanent submandibular gland alterations. Based on the present results and taking into account that O-LM is being safely administered in phase I clinical trial as an immunomodulator, we conclude that O-LM is a non-toxic promising approach to achieve radioprotection for patients undergoing radiotherapy.