Losac, the first hemolin that exhibits procogulant activity through selective factor X proteolytic activation

Inflammatory Progression in Patients Undergoing Extracorporeal Membrane Oxygenation

Extracorporeal membrane oxygenation (ECMO) is identified as a novel therapeutic strategy that offers short-term support to the metabolism of the heart and lungs in humans. Recently, the clinical centers, which provide ECMO has increased rapidly worldwide. The indications for the use of ECMO in daily clinical practice were broadened dynamically. However, even with the widespread adoption of ECMO, it still remains significant morbidity and mortality, and the underlying mechanisms are still not elucidated. Notably, one of the vital complications during ECMO was proposed as the inflammatory progression within the extracorporeal circulation. via the development of inflammatory response, patients with ECMO may further suffer from systemic inflammatory response syndrome (SIRS), posing serious risks to human health. Recently, growing evidence confirmed that through exposure of blood into the ECMO circuit could lead to the stimulation of the immune system which also facilitated the inflammatory response and systemic impaired. In the current review, the pathological development of inflammatory progression in patients with ECMO is well-listed. Furthermore, the relationship between immune-related activation and the development of inflammation is also summarized, which may further help us to decide the therapeutic strategies in daily clinical practice.

Horizontal gene transfer underlies the painful stings of asp caterpillars (Lepidoptera: Megalopygidae)

Larvae of the genus Megalopyge (Lepidoptera: Zygaenoidea: Megalopygidae), known as asp or puss caterpillars, produce defensive venoms that cause severe pain. Here, we present the anatomy, chemistry, and mode of action of the venom systems of caterpillars of two megalopygid species, the Southern flannel moth Megalopyge opercularis and the black-waved flannel moth Megalopyge crispata. We show that megalopygid venom is produced in secretory cells that lie beneath the cuticle and are connected to the venom spines by canals. Megalopygid venoms consist of large aerolysin-like pore-forming toxins, which we have named megalysins, and a small number of peptides. The venom system differs markedly from those of previously studied venomous zygaenoids of the family Limacodidae, suggestive of an independent origin. Megalopygid venom potently activates mammalian sensory neurons via membrane permeabilization and induces sustained spontaneous pain behavior and paw swelling in mice. These bioactivities are ablated by treatment with heat, organic solvents, or proteases, indicating that they are mediated by larger proteins such as the megalysins. We show that the megalysins were recruited as venom toxins in the Megalopygidae following horizontal transfer of genes from bacteria to the ancestors of ditrysian Lepidoptera. Megalopygids have recruited aerolysin-like proteins as venom toxins convergently with centipedes, cnidarians, and fish. This study highlights the role of horizontal gene transfer in venom evolution.

Losac and Lopap Recombinant Proteins from Lonomia obliqua Bristles Positively Modulate the Myoblast Proliferation Process

The pursuit of better therapies for disorders creating deficiencies in skeletal muscle regeneration is in progress, and several biotoxins are used in skeletal muscle research. Since recombinant proteins derived from Lonomia obliqua bristles, recombinant Lonomia obliqua Stuart-factor activator (rLosac) and recombinant Lonomia obliqua prothrombin activator protease (rLopap) act as cytoprotective agents and promote cell survival, we hypothesize that both rLosac and rLopap favour the skeletal muscle regeneration process. In the present work, we investigate the ability of these recombinant proteins rLosac and rLopap to modulate the production of key mediators of the myogenic process. The expression of myogenic regulatory factors (MRFs), cell proliferation, the production of prostaglandin E2 (PGE₂) and the protein expression of cyclooxygenases COX-1 and COX-2 were evaluated in C2C12 mouse myoblasts pre-treated with rLosac and rLopap. We found an increased proliferation of myoblasts, stimulated by both recombinant proteins. Moreover, these proteins modulated PGE₂ release and MRFs activities. We also found an increased expression of the EP4 receptor in the proliferative phase of C2C12 cells, suggesting the involvement of this receptor in the effects of PGE₂ in these cells. Moreover, the recombinant proteins inhibited the release of IL-6 and PGE₂, which is induced by an inflammatory stimulus by IL-1β. This work reveals rLopap and rLosac as promising proteins to modulate processes involving tissue regeneration as occurs during skeletal muscle injury.

Lonomia obliqua Envenoming and Innovative Research

As a tribute to Butantan Institute in its 120th anniversary, this review describes some of the scientific research efforts carried out in the study of Lonomia envenoming in Brazil, a country where accidents with caterpillars reach over 42,000 individuals per year (especially in South and Southeast Brazil). Thus, the promising data regarding the studies with Lonomia’s toxins contributed to the creation of new research centers specialized in toxinology based at Butantan Institute, as well as to the production of the antilonomic serum (ALS), actions which are in line with the Butantan Institute mission “to research, develop, manufacture, and provide products and services for the health of the population”. In addition, the study of the components of the Lonomia obliqua bristle extract led to the discovery of new molecules with peculiar properties, opening a field of knowledge that could lead to the development and innovation of new drugs aimed at cell regeneration and inflammatory diseases.

From Animal Poisons and Venoms to Medicines: Achievements, Challenges and Perspectives in Drug Discovery

Animal poisons and venoms are comprised of different classes of molecules displaying wide-ranging pharmacological activities. This review aims to provide an in-depth view of toxin-based compounds from terrestrial and marine organisms used as diagnostic tools, experimental molecules to validate postulated therapeutic targets, drug libraries, prototypes for the design of drugs, cosmeceuticals, and therapeutic agents. However, making these molecules applicable requires extensive preclinical trials, with some applications also demanding clinical trials, in order to validate their molecular target, mechanism of action, effective dose, potential adverse effects, as well as other fundamental parameters. Here we go through the pitfalls for a toxin-based potential therapeutic drug to become eligible for clinical trials and marketing. The manuscript also presents an overview of the current picture for several molecules from different animal venoms and poisons (such as those from amphibians, cone snails, hymenopterans, scorpions, sea anemones, snakes, spiders, tetraodontiformes, bats, and shrews) that have been used in clinical trials. Advances and perspectives on the therapeutic potential of molecules from other underexploited animals, such as caterpillars and ticks, are also reported. The challenges faced during the lengthy and costly preclinical and clinical studies and how to overcome these hindrances are also discussed for that drug candidates going to the bedside. It covers most of the drugs developed using toxins, the molecules that have failed and those that are currently in clinical trials. The article presents a detailed overview of toxins that have been used as therapeutic agents, including their discovery, formulation, dosage, indications, main adverse effects, and pregnancy and breastfeeding prescription warnings. Toxins in diagnosis, as well as cosmeceuticals and atypical therapies (bee venom and leech therapies) are also reported. The level of cumulative and detailed information provided in this review may help pharmacists, physicians, biotechnologists, pharmacologists, and scientists interested in toxinology, drug discovery, and development of toxin-based products.

Caterpillar Venom: A Health Hazard of the 21st Century

Caterpillar envenomation is a global health threat in the 21st century. Every direct or indirect contact with the urticating hairs of a caterpillar results in clinical manifestations ranging from local dermatitis symptoms to potentially life-threatening systemic effects. This is mainly due to the action of bioactive components in the venom that interfere with targets in the human body. The problem is that doctors are limited to relieve symptoms, since an effective treatment is still lacking. Only for Lonomia species an effective antivenom does exist. The health and economical damage are an underestimated problem and will be even more of a concern in the future. For some caterpillar species, the venom composition has been the subject of investigation, while for many others it remains unknown. Moreover, the targets involved in the pathophysiology are poorly understood. This review aims to give an overview of the knowledge we have today on the venom composition of different caterpillar species along with their pharmacological targets. Epidemiology, mode of action, clinical time course and treatments are also addressed. Finally, we briefly discuss the future perspectives that may open the doors for future research in the world of caterpillar toxins to find an adequate treatment.

Characterization of L-amino Acid Oxidase Derived from Crotalus adamanteus Venom: Procoagulant and Anticoagulant Activities

Snake venom enzymes of the L-amino acid oxidase (LAAO) class are responsible for tissue hemorrhage, edema, and derangement of platelet function. However, what role, if any, these flavoenzymes play in altering plasmatic coagulation have not been well defined. Using coagulation kinetomic analyses (thrombelastograph-based), it was determined that the LAAO derived from Crotalus adamanteus venom displayed a procoagulant activity associated with weak clot strength (no factor XIII activation) similar to thrombin-like enzymes. The procoagulant activity was not modified in the presence of reduced glutathione, demonstrating that the procoagulant activity was likely due to deamination, and not hydrogen peroxide generation by the LAAO. Further, unlike the raw venom of the same species, the purified LAAO was not inhibited by carbon monoxide releasing molecule-2 (CORM-2). Lastly, exposure of the enzyme to phenylmethylsulfonyl fluoride (PMSF) resulted in the LAAO expressing anticoagulant activity, preventing contact activation generated thrombin from forming a clot. In sum, this investigation for the first time characterized the LAAO of a snake venom as both a fibrinogen polymerizing and an anticoagulant enzyme acting via oxidative deamination and not proteolysis as is the case with thrombin-like enzymes (e.g., serine proteases). Using this thrombelastographic approach, future investigation of purified enzymes can define their biochemical nature.

Neuroprotective effect of rLosac on supplement-deprived mouse cultured cortical neurons involves maintenance of monocarboxylate transporter MCT2 protein levels

The recombinant Lonomia obliqua Stuart-factor activator (rLosac) is a recombinant hemolin which belongs to the immunoglobulin superfamily of cell adhesion molecules. It is capable of inducing pro-survival activity in serum-deprived human umbilical vein endothelial cells (HUVECs) and fibroblasts by increasing mitochondrial metabolism. We hypothesize that it could promote neuronal survival by acting on neuroenergetics. Our study reveals that treatment of primary mouse cortical neurons cultured in neurobasal medium lacking B27 supplement with rLosac led to an enhancement of cell viability in a time- and concentration-dependent manner. In parallel, preserved or enhanced phosphorylation of Akt, p44, and p42 MAPK, as well as mTOR was observed following treatment with rLosac. During deprivation, as assessed by western blot and qRT-PCR, protein and mRNA expression of MCT2 (the predominant neuronal monocarboxylate transporter allowing lactate use as an alternative energy substrate) decreased significantly in B27 supplement-deprived cortical neurons and was hardly detected after 24 h of deprivation. Interestingly, rLosac maintained MCT2 protein expression after 24 h of deprivation including at the cell surface without preventing mRNA loss. MCT2 knockdown reduced rLosac-enhanced cell viability, confirming its involvement in rLosac effect. Enhanced uptake of lactate was detected following rLosac treatment and might contribute to rLosac-enhanced viability during deprivation. In the presence of both lactate and rLosac, cell viability was higher than in the presence of lactate alone. Our observations suggest that rLosac promotes cell viability in stressed (B27 supplement-deprived) neurons by facilitating the use of lactate as energy substrate via the preservation of MCT2 protein expression. OPEN SCIENCE BADGES: This article has received a badge for *Open Materials* because it provided all relevant information to reproduce the study in the manuscript. The complete Open Science Disclosure form for this article can be found at the end of the article. More information about the Open Practices badges can be found at https://cos.io/our-services/open-science-badges/.

Venomous caterpillars: From inoculation apparatus to venom composition and envenomation

Envenomation by the larval or pupal stages of moths occurs when the victim presses their hairs. They penetrate the subcutaneous tissue, releasing toxins such as proteolytic enzymes, histamine and other pro-inflammatory substances. Cutaneous reactions, including severe pain, oedema and erythema are frequent local manifestations of caterpillar envenomation, but, in some cases, the reactions can evolve into vesicles, bullae, erosions, petechiae, superficial skin necrosis and ulcerations. Alternatively, some individual can develop allergic reactions, renal failure, osteochondritis, deformity and immobilization of the affected joints and intracerebral bleeding. Caterpillars produce venom to protect themselves from predators; contact with humans is accidental and deserves close attention. Their venoms have not been well studied, except for toxins from some few species. The present review brings together data on venomous caterpillars of moths, primarily addressing the available literature on diversity among the different families that cause accident in humans, the structures used in their defense, venom composition and clinical aspects of the envenomations. Understanding the molecular mechanisms of action of caterpillars' toxins may lead to the development of more adequate treatments.

Functional characterisation of Vizottin, the first factor Xa inhibitor purified from the leech Haementeria vizottoi

The strategic position of factor Xa (FXa) in blood coagulation makes it a compelling target for the development of new anticoagulants. Bloodsucking animals have in their salivary glands mixtures of anticoagulants, which could be used for designing novel antithrombotic compounds. Herein, we describe Vizottin, the first FXa inhibitor from the salivary complex of the leech Haementeria vizottoi. Vizottin was purified by gel filtration and reverse-phase chromatography, and shown to have anticoagulant effects in human plasma, prolonging the recalcification time in a dose-dependent manner (IC50 40 nM). Vizottin induced blood incoagulability in FX-deficient plasma, whereas in normal and reconstituted plasma, Vizottin doubled the prothrombin time at 160 nM. This peptide competitively inhibited human FXa (Ki 2 nM) like FXa inhibitors from other leeches, albeit via a distinct mechanism of action. At high concentrations, vizottin inhibited the amidolytic activity of factor VIIa/tissue factor (IC50 96.4 nM). Vizottin inhibited FXa in the prothrombinase complex and Gla-domainless FXa. Moreover, vizottin did not interfere with FX activation induced by RVV-X, a known enzyme that requires the Gla-domain of FX for activation. Competition experiments in the presence of FXa and GGACK-FXa (active site blocked) demonstrated that the inhibition of FXa by vizottin is through binding to the active site rather than an exosite. This novel inhibitor appears to exert its inhibitory effects through direct binding to the active site of FXa in a time-dependent manner, but not involving a tight-binding model. In this context, vizottin is a promising model for designing novel anticoagulants for the treatment of thrombotic diseases.

Regulation by gut bacteria of immune response, Bacillus thuringiensis susceptibility and hemolin expression in Plodia interpunctella

Plodia interpunctella (Hübner) is an important stored grain insect pest worldwide, and the first lepidopteran with reported resistance to Bacillus thuringiensis (Bt) toxins. Since gut bacteria may affect Bt insecticidal activity, we evaluated whether P. interpunctella lacking gut bacteria had differences in immune responses and susceptibility to the Bt formulation, Bactospeine. In order to clear gut bacteria, third instar larvae were reared on artificial diet containing antibiotics, or were obtained from sterilized eggs and reared under sterile conditions, and larvae were fed diets with or without Bt. Mortality was significantly lower (p<0.05) in bacteria-free larvae treated with Bt, compared with Bt-treated larvae with unaffected gut bacteria. The number of hemocytes was lower in control and Bt-treated larvae, but was significantly higher (p<0.001) in larvae treated with antibiotics and Bt, and larvae from presterilized eggs and reared on sterile diet had the highest number of hemocytes. Phenoloxidase activity was significantly lower (p<0.05) in Bt-treated larvae from presterilized eggs reared on antibiotics for 24h or in larvae reared on antibiotic-treated diets prior to Bt introduction compared with those fed control diet. Hemolin gene expression was reduced in larvae fed Bt diets compared with control and was not detected in larvae treated with antibiotics. Larvae from sterilized eggs and fed sterile diet never reached the pupal stage. Therefore, the loss of gut bacteria in P. interpunctella larvae affected the host immune response and expression of the hemolin gene, and significantly reduced susceptibility to Bt.

Exploring the in vivo wound healing effects of a recombinant hemolin from the caterpillar Lonomia obliqua

Background

Hemolin proteins are cell adhesion molecules from lepidopterans involved in a wide range of cell interactions concerning their adhesion properties. However, hemolin’s roles in cell proliferation and wound healing are not fully elucidated. It has been recently reported that rLosac, a recombinant hemolin from the caterpillar Lonomia obliqua, presents antiapoptotic activity and is capable of improving in vitro wound healing. Therefore, this study aimed to explore rLosac’s in vivo effects using a skin wound healing model in rats.

Methods

Circular full-thickness wounds in the rat dorsum skin were treated either with rLosac, or with saline (control), allowing healing by keeping the wounds occluded and moist. During the wound healing, the following tissue regeneration parameters were evaluated: wound closure and collagen content. Furthermore, tissue sections were subjected to histological and immunohistochemical analyses.

Results

The rLosac treatment has demonstrated its capacity to improve wound healing, as reflected in findings of a larger number of activated fibroblasts, proliferation of epithelial cells, increase of collagen type 1, and decrease of inflammatory infiltrate.

Conclusion

The findings have indicated the rLosac protein as a very promising molecule for the development of new wound-healing formulations.

Hemolin triggers cell survival on fibroblasts in response to serum deprivation by inhibition of apoptosis

Fibroblasts are the main cellular component of connective tissues and play important roles in health and disease through the production of collagen, fibronectin and growth factors. Under certain conditions, such as wound healing, fibroblasts intensify their metabolic demand, while the restriction of nutrients affect matrix composition, cell metabolism and behavior. In lepidopterans, wound healing is regulated by ecdysteroid hormones, which upregulate multifunctional proteins such as hemolin. However, the role of hemolin in cell proliferation and wound healing is not clear. rLosac is a recombinant hemolin from the caterpillar Lonomia obliqua whose proliferative and cytoprotective effects on endothelial cells have been described. Here, we show that rLosac induces a marked cell survival effect on fibroblast submitted to serum deprivation, which is observable as early as 24h, as demonstrated through the MTT assay, as well as an increase in migration of human dermal fibroblasts (HDF). No effects on cell proliferation or cell cycle distribution of fibroblasts in normal conditions were observed, suggesting that rLosac induces an effect in stressful conditions such serum deprivation but not when nutrient are sufficient. By flow cytometry, rLosac caused an apparent dose-dependent increase in cells in the S phase of the cell cycle and a significant reduction of cells with fragmented DNA. Furthermore, treatment with rLosac results in a significant decrease in the production of reactive oxygen species and in the loss of mitochondrial membrane potential, indicating that a reduction in oxidative stress is involved in rLosac-mediated cytoprotection. Our results also show an up-regulation of Bcl-2 and a down-regulation of Bax protein levels, inhibition of cytochrome c release and a reduction in caspase-3 levels, all considered critical factors for apoptosis. Moreover, rLosac treatment reduces the morphological changes induced by prolonged serum deprivation including the emergence of apoptotic bodies, nucleus fragmentation, cytoplasmic vacuolization and loss of extracellular matrix organization. The wound scratch test assay revealed that rLosac could enhance wound healing in vitro. Altogether, these findings suggest that rLosac strongly induces cellular protection in conditions of stress by serum deprivation preventing damage and loss of mitochondrial function by inhibiting apoptosis. This finding opens a new perspective to further understand the role of hemolin proteins during cellular processes such as wound healing and development.

Lonomia obliqua Walker (Lepidoptera: Saturniidae): hemostasis implications

Summary In southern Brazil, since 1989, several cases of accidents produced by unwilling contact with the body of poisonous caterpillars of the moth species Lonomia obliqua Walker, 1855 (Lepidoptera: Saturniidae), were described. L. obliqua caterpillars have gregarious behavior and feed on leaves of host trees during the night, staying grouped in the trunk during the day, which favors the occurrence of accidents with the species. This caterpillar has the body covered with bristles that on contact with the skin of individuals, breaks and release their contents, inoculating the venom into the victim. The basic constitution of the venom is protein and its components produce physiological changes in the victim, which include disturbances in hemostasis. Hemorrhagic syndrome associated with consumption coagulopathy, intravascular hemolysis and acute renal failure are some of the possible clinical manifestations related to poisoning by L. obliqua. Specific laboratory tests for diagnosis of poisoning have not been described previously. The diagnosis of poisoning is made based on the patient's medical history, clinical manifestations, erythrocyte levels, and, primarily, parameters that evaluate blood coagulation. Treatment is performed with the use of supportive care and the administration of specific hyperimmune antivenom. Poisoning can be serious and even fatal.