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Phosphodiesterases (PDEs) constitute an enzyme group able to hydrolyze nucleic acids as well as some second messengers. Due to this ability and their expression in several human tissues and organs, PDEs can control a gamut of physiological processes. They are also involved in some pathological conditions, such as Alzheimer's disease and erectile dysfunction. PDEs are also expressed in snake venom glands, being called snake venoms phosphodiesterases, or simply svPDEs. The occurrence of these enzymes has already been reported in crotalid, elapid and viperid venoms, such as Crotalus, Naja and Trimeresurus, respectively, but not all of them have been characterized concerning their structure, activity and function. In this review, we are addressing general characteristics of svPDEs, in addition to their structural, biochemical and functional characteristics, and we also report some potential applications of svPDEs.

Snakebite envenoming is currently considered a neglected tropical disease, which affects over 5 million people worldwide, and causes almost 150 000 deaths every year, as well as severe injuries, amputations and other sequelae. Snakebite envenoming in children, although proportionally less frequent, is generally more severe, and represents an important challenge for pediatric medicine, since they often result in worse outcomes. In Brazil, given its ecological, geographic and socioeconomic characteristics, snakebites are considered an important health problem, presenting approximately 30 000 victims per year, approximately 15% of them in children. Even with low snakebite incidence, children tend to have higher snakebite severity and complications due to the small body mass and same venom volume inoculated in comparison to adults, even though, due to the lack of epidemiological information about pediatric snakebites and induced injuries, it is difficult to measure the treatment effectiveness, outcomes and quality of emergency medical services for snakebites in children. In this review, we report how Brazilian children are affected by snakebites, describing the characteristics of this affected population, clinical aspects, management, outcomes and main challenges.

Over the years, vaccinations have provided significant advances in public health, because they substantially reduce the morbimortality of vaccine-preventable diseases. Nevertheless, many people are still hesitant to be vaccinated. Brazil is a region of many anti-vaccine movements, and several outbreaks of vaccine-preventable diseases, such as yellow fever and measles, have occurred in the country during the last few years. To avoid new outbreaks, immunization coverage must be high; however, this is a great challenge to achieve due to the countless anti-vaccine movements. The World Health Organization has suggested new actions for the next decade via the Immunization Agenda 2030 to control, reduce, or eradicate vaccine-preventable diseases. Nonetheless, the vaccination coverage has decreased recently. To resolve the anti-vaccine issue, it is necessary to propose a long-term approach that involves innovative education programs on immunization and critical thinking, using different communication channels, including social media. Cooperation among biology and health scientists, ethicists, human scientists, policymakers, journalists, and civil society is essential for an in-depth understanding of the social action of vaccine refusal and planning effective education measures to increase the vaccine coverage.

The two-striped forest-pitviper (Bothrops bilineatus) is an arboreal snake that is currently represented by two subspecies (B. b. bilineatusandB. b. smaragdinus) that comprise a species complex, and its distribution is in the Amazon and the Atlantic Forest. The rarity of encounters with this snake is reflected in the low occurrence of cases of snakebites throughout its geographic distribution and the resulting low number of published clinical reports. However, in some areas,B. bilineatusproves to be more frequent and causes envenomations in a greater proportion. Herein, we review the main aspects of the species complexB. bilineatus, including its biology, ecology, taxonomy, morphology, genetic and molecular studies, geographic distribution, conservation status, venom, pathophysiology and clinical aspects, and epidemiology. In addition, the different antivenoms available for the treatment of envenomations caused byB. bilineatusare presented along with suggestions for future studies that are needed for a better understanding of the snakebites caused by this snake.

Snakebite envenomings are considered a global health problem. The specific therapy for these envenomings consists of administering animal-derived antivenoms aiming to neutralize the venom toxins. Antivenoms have been used effectively to treat snakebites for more than a century; however, their administration may result in early and/or late adverse reactions. The present study presents the prevalence of early adverse reactions (EARs) towards Bothrops antivenom therapy in a health tertiary unit in the Brazilian Amazon and explores if specific plasma cytokines and chemokines from envenomed patients could be used as predictors of EARs. A cohort of patients bitten by Bothrops atrox was followed-up at the Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), from 2014 to 2016. Patients were treated with the Brazilian Bothrops antivenom and CXCL-8, CCL-5, CXCL-9, CCL-2, CXCL-10, IL-6, TNF, IL-2, IL-10, IFN-y, IL-4, and IL-17A were evaluated in patients' plasma samples before and after antivenom administration. From the total of patients (n = 186), mostly were male (82.3%), inhabiting rural areas (87.1%), with an average age of 35 years. Most of the patients (83.8%) were admitted to the hospital within 6 h after the accident, 26 (14%) reported having suffered a previous snakebite, and 97 (52.1%) received between 7 and 9 antivenom vials. The frequency of antivenom-induced EARs was 11.8% (22), resulting mostly of mild reactions. Urticaria was the major EAR manifestation (46.4%). Interestingly, CXCL-8 and IL-2 showed significantly lower levels in patients who progressed to EARs, although IL-2 levels might not represent biological relevance due the small magnitude difference between groups. This study reveals that CXCL-8 and IL-2 could play a role in the onset of EARs in pit viper envenomings.

Vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis, a physiological process characterized by the formation of new vessels from a preexisting endothelium. VEGF has also been implicated in pathologic states, such as neoplasias, intraocular neovascular disorders, among other conditions. VEGFs are distributed in seven different families: VEGF-A, B, C, D, and PIGF (placental growth factor), which are identified in mammals; VEGF-E, which are encountered in viruses; and VEGF-F or svVEGF (snake venom VEGF) described in snake venoms. This is the pioneer review of svVEGF family, exploring its distribution among the snake venoms, molecular structure, main functions, and potential applications.

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.

Bushmasters (Lachesis spp) and lancehead vipers (Bothrops spp) are two of the most dangerous snakes found in Latin America. Victims of envenoming by these snakes require urgent administration of antivenom. Here, we report the identification of a small set of broadly neutralizing human monoclonal single-chain variable fragment (scFv) antibodies targeting key phospholipases A

The hygiene hypothesis was proposed almost three decades ago. Nevertheless, its mechanism still remains with relevant controversies. Some studies defend that early exposures during childhood to microbes and parasites are key determinants to prevent allergies and autoimmune diseases; however, other studies demonstrated that these early exposures can even potentiate the clinical scenario of the diseases. Based on several studies covering the influences of microbiome, parasites, related theories and others, this review focuses on recent advances in the hygiene hypothesis field. In addition, the main immunological mechanisms underlying the hygiene hypothesis are also discussed. We also strongly encourage that researchers do not consider the hygiene hypothesis as a theory based strictly on hygiene habits, but a theory combining diverse influences, as illustrated in this review as the hygiene hypothesis net.

Made available in DSpace on 2020-12-12T02:25:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-04-20 School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Brazil; University of Leuven, Belgium; School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Brazil; Department of Biochemistry and Immunology, Medical School, University of São Paulo, Brazil; Medical School of Roraima, Federal University of Roraima, Brazil; Institute of Biosciences, São Paulo State University (UNESP), Botucatu, Brazil; School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Brazil

Bushmasters (Lachesis spp) and lancehead vipers (Bothrops spp) are two of the most dangerous snakes found in Latin America. Victims of envenoming by these snakes require urgent administration of antivenom. Here, we report the identification of a small set of broadly neutralizing human monoclonal single-chain variable fragment (scFv) antibodies targeting key phospholipases A2 from Lachesis and Bothrops spp using phage display technology and demonstrate their in vitro efficacy using a hemolysis assay.

Made available in DSpace on 2020-12-12T02:37:19Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-12-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) KU Leuven Fonds Wetenschappelijk Onderzoek Snake venom serine proteases (SVSPs) are complex and multifunctional enzymes, acting primarily on hemostasis. In this work, we report the hitherto unknown inhibitory effect of a SVSP, named collinein-1, isolated from the venom of Crotalus durissus collilineatus, on a cancer-relevant voltage-gated potassium channel (hEAG1). Among 12 voltage-gated ion channels tested, collinein-1 selectively inhibited hEAG1 currents, with a mechanism independent of its enzymatic activity. Corroboratively, we demonstrated that collinein-1 reduced the viability of human breast cancer cell line MCF7 (high expression of hEAG1), but does not affect the liver carcinoma and the non-tumorigenic epithelial breast cell lines (HepG2 and MCF10A, respectively), which present low expression of hEAG1. In order to obtain both functional and structural validation of this unexpected discovery, where an unusually large ligand acts as an inhibitor of an ion channel, a recombinant and catalytically inactive mutant of collinein-1 (His43Arg) was produced and found to preserve its capability to inhibit hEAG1. A molecular docking model was proposed in which Arg79 of the SVSP 99-loop interacts directly with the potassium selectivity filter of the hEAG1 channel. School of Pharmaceutical Sciences of Ribeirão Preto University of São Paulo Av. do Café s/n° Toxicology and Pharmacology KU Leuven, O&N II Herestraat 49, PO 922 Medical School of Roraima Federal University of Roraima Av. Capitão Ene Garcez 2413 Bairro Aeroporto Institute of Biosciences São Paulo State University (UNESP) Rua Prof. Dr. Antonio Celso Wagner Zanin 250 University of Vila Velha Av. Comissário José Dantas de Melo 21 Boa Vista II Institute of Biosciences São Paulo State University (UNESP) Rua Prof. Dr. Antonio Celso Wagner Zanin 250 FAPESP: 2011/23236-4 FAPESP: 2015/00740-0 FAPESP: 2015/17286-0 FAPESP: 2016/04761-4 FAPESP: 2016/24191-8 FAPESP: 2017/14035-1 FAPESP: 2018/14158-9 CNPq: 307155/2017-0 CAPES: 88881.186830/2018-01 KU Leuven: CELSA 17/047 Fonds Wetenschappelijk Onderzoek: GOA4919N

Introduction: In Brazil, viral hepatitis is infectious disease of compulsory notification and is considered a serious public health problem. Infections with A, B, C, D or E viruses trigger the activation of immune system molecules and cells at the level of innate and acquired immunity. Objective: The present study aimed to review the knowledge about viral hepatitis and the immune system's performance against these infections. Methods: This is a literature overview from academic books and scientific articles available in the Scientific Electronic Library Online, US National Library of Medicine National Institutes of Health and Google Scholar databases. Having as key words hepatitis A, hepatitis B, hepatitis C, hepatitis D, hepatitis E and immune system. The relevant articles corresponding to the period between 1974 and 2017 were selected. Development: Viral hepatitis is characterized by inflammation in liver cells caused by groups of viruses that have hepatotropism in common. The diagnosis is made through serological methods and molecular biology techniques. The approach of the immune system in relation to the combat of this infection follows same particularities. Conclusion: This review demonstrated that the determination of the etiologic agent is essential for the conduct to be taken with the infected individual. Moreover, the immune system is directed related to the viruses elimination, presenting some particularities. In addition, this review highlights that the vaccination is the main responsible for reducing people infected by viruses A and B.

Introduction: The toxoplasmosis disease resulting from Toxoplasma gondii infection can manifest itself in many ways, however, congenital, ocular and cerebral forms require greater care. The infection by this protozoan is directly related to environmental and economic factors of the region. Objective: The present study, through a review in the literature, aimed to reinforce the knowledge about the infection caused by Toxoplasma gondii and its main clinical manifestations. Methods: This is a literature overview from academic books and scientific articles available in the Scientific Electronic Library Online, US National Library of Medicine National Institutes of Health and Google Scholar databases. To search the publications, the following descriptors were used: Toxoplasma gondii, toxoplasmosis, congenital toxoplasmosis, ocular toxoplasmosis and cerebral toxoplasmosis. The most relevant articles corresponding to the period from 2000 to 2017 were selected. Development: Toxoplasmosis may be of congenital or acquired origin after birth. The congenital form occurs during the embryonic/fetal life and through the passage of Toxoplasma gondii through the transplacental route. Ocular disease is common in both congenital and acquired infections and is closely associated with the presence of neurotoxoplasmosis in AIDS patients. Conclusion: Thus, immunocompromised patients and immunosuppressed patients are considered to be risk groups for Toxoplasma gondii infection.

Cysteine-rich secretory proteins (CRISPs) are commonly described as part of the protein content of snake venoms, nevertheless, so far, little is known about their biological targets and functions. Our study describes the isolation and characterization of Bj-CRP, the first CRISP isolated from Bothrops jararaca snake venom, also aiming at the identification of possible targets for its actions. Bj-CRP was purified using three chromatographic steps (Sephacryl S-200, Source 15Q and C18) and showed to be an acidic protein of 24.6kDa with high sequence identity to other snake venom CRISPs. This CRISP was devoid of proteolytic, hemorrhagic or coagulant activities, and it did not affect the currents from 13 voltage-gated potassium channel isoforms. Conversely, Bj-CRP induced inflammatory responses characterized by increase of leukocytes, mainly neutrophils, after 1 and 4h of its injection in the peritoneal cavity of mice, also stimulating the production of IL-6. Bj-CRP also acted on the human complement system, modulating some of the activation pathways and acting directly on important components (C3 and C4), thus inducing the generation of anaphylatoxins (C3a, C4a and C5a). Therefore, our results for Bj-CRP open up prospects for better understanding this class of toxins and its biological actions.

Scorpion venoms are natural sources of molecules that have, in addition to their toxic function, potential therapeutic applications. In this source the neurotoxins can be found especially those that act on potassium channels. Potassium channels are responsible for maintaining the membrane potential in the excitable cells, especially the voltage-dependent potassium channels (Kv), including Kv1.3 channels. These channels (Kv1.3) are expressed by various types of tissues and cells, being part of several physiological processes. However, the major studies of Kv1.3 are performed on T cells due its importance on autoimmune diseases. Scorpion toxins capable of acting on potassium channels (KTx), mainly on Kv1.3 channels, have gained a prominent role for their possible ability to control inflammatory autoimmune diseases. Some of these toxins have already left bench trials and are being evaluated in clinical trials, presenting great therapeutic potential. Thus, scorpion toxins are important natural molecules that should not be overlooked in the treatment of autoimmune and other diseases.

Antibody technologies are being increasingly applied in the field of toxinology. Fuelled by the many advances in immunology, synthetic biology, and antibody research, different approaches and antibody formats are being investigated for the ability to neutralize animal toxins. These different molecular formats each have their own therapeutic characteristics. In this review, we provide an overview of the advances made in the development of toxin-targeting antibodies, and discuss the benefits and drawbacks of different antibody formats in relation to their ability to neutralize toxins, pharmacokinetic features, propensity to cause adverse reactions, formulation, and expression for research and development (R&D) purposes and large-scale manufacturing. A research trend seems to be emerging towards the use of human antibody formats as well as camelid heavy-domain antibody fragments due to their compatibility with the human immune system, beneficial therapeutic properties, and the ability to manufacture these molecules cost-effectively. Novo Nordisk Foundation/[16OC0019248]/NNF/Dinamarca Novo Nordisk Foundation/[13OC0005613]/NNF/Dinamarca Ministerio de Ciencia, Tecnología y Telecomunicaciones/[PEM-066-2015-II]/MICITT/Costa Rica Conselho Nacional de Desenvolvimento Científico e Tecnologico/[150749/2017-1]/CNPq/Brasil Universidad de Costa Rica/[OAICE-CAB-05-56-2016]/UCR/Costa Rica UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto Clodomiro Picado (ICP) UCR::Vicerrectoría de Docencia::Salud::Facultad de Microbiología

Tityus serrulatus (Ts) venom is composed of mainly neurotoxins specific for voltage-gated K+ and Na+ channels, which are expressed in many cells such as macrophages. Macrophages are the first line of defense invasion and they participate in the inflammatory response of Ts envenoming. However, little is known about the effect of Ts toxins on macrophage activation. This study investigated the effect of Ts5 toxin on different sodium channels as well as its role on the macrophage immunomodulation. The electrophysiological assays showed that Ts5 inhibits the rapid inactivation of the mammalian sodium channels Nav1.2, Nav1.3, Nav1.4, Nav1.5, Nav1.6 and Nav1.7. Interestingly, Ts5 also inhibits the inactivation of the insect Drosophila melanogaster sodium channel (DmNav1), and it is therefore classified as the first Ts α-like toxin. The immunological experiments on macrophages reveal that Ts5 is a pro-inflammatory toxin inducing the cytokine production of tumor necrosis factor (TNF)-α and interleukin (IL)-6. On the basis of recent literature, our study also stresses a possible mechanism responsible for venom-associated molecular patterns (VAMPs) internalization and macrophage activation and moreover we suggest two main pathways of VAMPs signaling: direct and indirect. This work provides useful insights for a better understanding of the involvement of VAMPs in macrophage modulation.

Accidents involving venomous snakes are a public health problem worldwide, causing a large number of deaths per year. In Brazil, the majority of accidents are caused by the Bothrops and Crotalus genera, which are responsible for approximately 80% of severe envenoming cases. The cross-neutralization of snake venoms by antibodies is an important issue for development of more effective treatments. Our group has previously reported the construction of human monoclonal antibody fragments towards Bothrops jararacussu and Crotalus durissus terrificus’ venoms. This study aimed to select human single-chain variable fragments (scFvs) that recognize both bothropic and crotalic crude venoms following venoms neutralizing capacity in vitro and in vivo. The cross-reactivity of Cro-Bothrumabs were demonstrated by ELISA and in vitro and in vivo experiments showed that a combination of scFvs neutralizes in vitro toxic activities (e.g. indirect hemolysis and plasma-clotting) of crotalic and bothropic venoms as well as prolonged survival time of envenomed animals. Our results may contribute to the development of the first human polyvalent antivenom against Bothrops jararacussu and Crotalus durissus terrificus venoms, overcoming some undesirable effects caused by conventional serotherapy.

Introduction: The Amazonas is the largest state of Brazil, being located in the northwestern of the country. Nevertheless, the Amazonas is not so populous; its population corresponds only to 1.9% (4,063,614 habitants) from the population of Brazil. On the other hand, the state is famous for its rich flora and fauna including venomous animals such as snakes, spiders and scorpions. Therefore, epidemiological studies of venomous animal accidents in the region becomes essential for the development of better therapeutical strategies and preventing actions to reduce the occurrence of these accidents. Objective: The present study aimed to perform an epidemiological analysis of accidents caused by venomous animals in the Amazonas state from 2012 to 2015. Methods: The data were obtained by consulting the Sistema de Informação de Agravos de Notificação (SINAN, Information System for Notifiable Diseases) and Sistema Nacional de Informações Tóxico-Farmacológicas (SINITOX, National System of Toxic-Pharmacological Information) databases. Data of accidents caused by venomous animals between 2012 and 2015 were collected from the Amazonas 60 municipalities. The variables analyzed were: year of highest incidence, municipality with the highest incidence, age of the victims, sex of the victim, animal responsible for the accident, time interval between the accident and therapeutics and deaths. Results: During the years 2012 to 2015, a total of 9,349 cases of accidents involving venomous animals were reported in Amazonas state, with most victims registered in Manaus (1,331 cases). Most of the victims present 20 to 39 years-old and were male. The snakes were responsible for the most accidents, followed by scorpions. Most of the victims reach the hospital and start the therapy between 1 to 3 hours after the accident. The deaths in the state present less than 20 cases per year. Conclusion: This study expands the knowledge about the epidemiological profile of venomous animal accidents in Amazonas state, which is crucial for quantifying the disease burden, contributing to evidence-based healthcare planning, and evaluating effectiveness and relative contribution of primary, secondary and tertiary preventative measures for reducing these accidents and their complications in the region.

Tityus serrulatus (Ts) venom is composed of a mixture of toxins presenting diverse biological functions. However, although this venom has been studied over the past three decades, omics analysis revealed that most of its toxins are not identified or their biological activities are unknown. Ts19 Frag-II is included in this group, which function is still uncertain. This study aimed to expand the biological activities of Ts19 Frag-II through in vivo investigation. Our results demonstrates that mice challenged with Ts19 Frag-II presented biochemical alterations, increasing serum levels of urea, ALT and β-globulin, besides decreasing γ-globulins. Moreover, this toxin was also able to induce immunological alterations, increasing NO, IL-6, TNF-α and IL-17, being considered a proinflammatory toxin. The increase of IL-17 was unprecedented regarding Ts toxins and could be a result of the overall produced-effect of cells of innate immunity cells (neutrophils, monocytes, natural killers and lymphoid tissue inducers - LTis) as well as of adaptive immunity (Th17 cells). This study expanded the biological activities of Ts19 Frag-II, suggesting that this toxin could be contributing to the Ts envenoming through alterations of biochemical parameters as well as triggering the inflammatory response.

O escorpião Tityus serrulatus (Ts) é o responsável pela maioria casos de envenenamento escorpiônicos do Brasil. Embora sua peçonha seja constituída de inúmeros componentes, as neurotoxinas apresentam maior relevância por interagirem especificamente com canais para sódio (Nav) ou potássio (Kv) dependentes de voltagem. Até o momento, já foram descritas 20 neurotoxinas (Ts1 -> Ts20) na peçonha do Ts. No entanto, através de análises ômicas, estima-se que este número seja bem superior. Toxinas que interagem seletivamente com canais iônicos são utilizadas como ferramentas farmacológicas, pois permitem a identificação de canais específicos e a determinação de seus papéis fisiológicos. Adicionalmente, estas toxinas podem ser utilizadas para o desenvolvimento de novos medicamentos para tratar doenças relacionadas a canais iônicos. Considerando o elevado potencial biotecnológicos desta classe de moléculas, o presente trabalho isolou (através de 3 etapas cromatográficas) e caracterizou uma nova toxina da peçonha de Ts, denominada Ts19 Frag-II. A nova toxina demonstrou possuir 49 resíduos de aminoácidos e massa molecular de 5534,54012 Da. Classificada como ?-KTx, especula-se que a Ts19 Frag-II seja produzida a partir de uma modificação pós-transducional, denominada neste estudo de post-splitting, de um transcrito da Ts19. A caracterização funcional da Ts19 Frag-II foi realizada utilizando diferentes ensaios de atividade biológica. Uma extensa avaliação eletrofisiológica em canais iônicos (16 Kvs e 5 Navs) expressos em oócitos de X. leavis demonstrou que a toxina é capaz de bloquear seletivamente canais para potássio do tipo Kv1.2 (IC50 = 544 ± 32 nM). Ensaios in vivo (camundongos C57BL/6) de dor revelaram que a Ts19 Frag-II (2 e 4?g) não é capaz de induzir comportamento nociceptivo espontâneo ou mecânico em camundongos, tanto pela administração intraplantar quanto pela via intratecal. Ensaios in vivo (camundongos BALB/c) também demonstraram que a nova toxina (4 e 8?g) induz aumento dos níveis séricos de ureia, ALT, ?-globulina, IL-6, TNF-?, IL-17A e NO, além de diminuir a quantidade de ?-globulinas. Adicionalmente, utilizando ensaios in vitro de cultura celular de linfócitos T CD4+, demonstrou-se que a Ts19 Frag-II (2 ?g) foi capaz de diminuir a diferenciação de células Th17, assim como suprimir sua função (diminuiu a produção de IL-17 e IL-22). Assim, no presente estudo foi realizado o isolamento e a caracterização molecular e funcional de uma nova toxina de Ts, a qual apresentou atividade neurotóxica e pró-inflamatória, podendo contribuir significativamente para a gravidade do quadro de envenenamento ocasionado pelo escorpião Ts. Adicionalmente, sua seletividade para canais Kv1.2 faz com que Ts19 Frag-II possa ser utilizada como ferramenta de estudo deste canal iônico The scorpion Tityus serrulatus (Ts) is responsible for most cases of scorpion envenomations in Brazil. Although its venom consist of many components, neurotoxins present major relevance because their specific interaction with voltage-gated sodium (Nav) or potassium (Kv) channels. So far, 20 neurotoxins have been described (Ts1 -> Ts20) in the Ts venom. However, omics analysis indicate that this number is much higher. Toxins that interact selectively with ion channels are used as pharmacological tools, as they allow the identification of specific channels and the determination of their physiological roles. Additionally, these toxins may be used for the development of new drugs for treating disorders related to ion channels. Considering the high biotechnology potential of this class of molecules, this study isolated (by 3 chromatographic steps) and characterized a new toxin from Ts venom, named Ts19 Frag-II. The novel toxin presented 49 amino acid residues and a molecular mass of 5534.54012 Da. Classified as ? - KTx, it is speculated that the Ts19 Frag-II is produced from a post- translational modification, referred in this study as post- splitting, a transcript of Ts19. The functional characterization of Ts19 Frag-II was performed using different biological assays. The extensive electrophysiological study on ion channels (16 Kvs and 5 Navs) expressed in oocytes of X. leavis showed that the toxin is able to selectively block the potassium channel Kv1.2 (IC50 = 544 ± 32 nM). In vivo assays (C57BL/6 mice) of nociception showed that Ts19 Frag-II (2 and 4?g) is not able to induce spontaneous or mechanical nociceptive behavior in mice, both by intraplantar as by intrathecal administration. In vivo assays (BALB/c mice) also demonstrated that the novel toxin (4 and 8?g) increased serum levels of urea, ALT, ?-globulin, IL-6, TNF-?, IL-17A and NO, besides decreasing ?-globulins. In addition, using in vitro assays of CD4+ T-lymphocyte cell culture, it was demonstrated that Ts19 Frag-II (2 ug) was able to decrease the differentiation of Th17 cells, as well as it suppresses Th17 function (decreased IL-17 and IL-22 production). Therefore, the present study isolated and performed the molecular and functional characterization of a new toxin from Ts, which presented neurotoxic and pro-inflammatory activity and could contribute significantly to the severity of the envenoming caused by the Ts scorpion. Moreover, based on its selectivity for Kv1.2 channels, this toxin could be used as a tool to study this type of ion channel

The venom from the scorpion Tityus serrulatus (Ts) has been extensively studied mainly because of its rich cocktail of neurotoxins. Neurotoxins are the major and the most known components based on their modulation of voltage-gated ion channels. Until now, electrophysiological studies demonstrated that the Ts venom comprises toxins that affect Nav and Kv channels. However, although many studies have been conducted in this field, many peptides from Ts venom await further studies, including Ts8 toxin. Here we report the isolation and electrophysiological study of Ts8. The toxin Ts19 Frag-II was used as negative control. Ts8 demonstrates, among 20 tested channels, to be a selective modulator of Kv4.2 channels. Based on studies investigating the involvement of Kv4.2 on controlling nociception, we further investigated the modulation of pain by Ts8. Using intraplantar injections, Ts8 induced overt nociception (licking and lifting behaviors) and decreased the mechanical nociceptive threshold (hyperalgesia). Furthermore, the hyperalgesia was prolonged when intrathecal injections were performed. Independent of the severity, most of the victims stung by Ts scorpions report an intense and persistent pain as the major manifestation. The new role of Ts8 on nociception could explain, at least partially, this phenomenon. Additionally, our study also stresses the involvement of toxins specific to Nav channels and inflammatory mediators on the Ts painful sting. This work provides useful insights for a better understanding of the prolonged and intense pain associated with Ts envenoming for the development of specific therapies.

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.

The present study purifies two T. serrulatus non-disulfide-bridged peptides (NDBPs), named venom peptides 7.2 (RLRSKG) and 8 (KIWRS) and details their synthesis and biological activity, comparing to the synthetic venom peptide 7.1 (RLRSKGKK), previously identified. The synthetic replicate peptides were subjected to a range of biological assays: hemolytic, antifungal, antiviral, electrophysiological, immunological and angiotensin-converting enzyme (ACE) inhibition activities. All venom peptides neither showed to be cytolytic nor demonstrated significant antifungal or antiviral activities. Interestingly, peptides were able to modulate macrophages’ responses, increasing IL-6 production. The three venom peptides also demonstrated potential to inhibit ACE in the following order: 7.2 > 7.1 > 8. The ACE inhibition activity was unexpected, since peptides that display this function are usually proline-rich peptides. In attempt to understand the origin of such small peptides, we discovered that the isolated peptides 7.2 and 8 are fragments of the same molecule, named Pape peptide precursor. Furthermore, the study discusses that Pape fragments could be originated from a post-splitting mechanism resulting from metalloserrulases and other proteinases cleavage, which can be seen as a clever mechanism used by the scorpion to enlarge its repertoire of venom components. Scorpion venom remains as an interesting source of bioactive proteins and this study advances our knowledge about three NDBPs and their biological activities.