Use of point-of-care ultrasound to assess the severity of scorpion stings in hospitalized patients.

INTRODUCTION: Scorpionism is a public health problem, especially in tropical regions. In Brazil, the prevalence of envenomation by scorpions is high, and the average national lethality is around 0.16 percent. The Tityus serrulatus scorpion is the primary species of medical importance. However, objective tools to predict and define the severity of these envenomations are lacking. MATERIALS AND METHODS: This was an observational study conducted among patients aged 0-19 years with scorpionism. Patients were admitted to a reference hospital between December 2020 and May 2022. Point-of-care ultrasound was performed within 24 hours of the scorpion sting. RESULTS: Forty-nine patients were included, with a median age of 3.6 (interquartile range 2.3-5.3) years and a predominance of females (51 percent). Fifteen patients (30.6 percent) presented major life-threatening signs, 32 (65.3 percent) minor systemic manifestations, and two (4.1 percent) only local manifestations. Left ventricular dysfunction was identified in 13 patients (26.5 percent). Ten patients (20.4 percent) presented pattern B (visualization of three or more B lines in the evaluated quadrant) in at least one lung window. The sensitivity and specificity of cardiac and pulmonary ultrasound to identify the most severely ill patients were 86 percent and 94 percent, respectively. DISCUSSION: The changes found on point-of-care ultrasound were associated with life-threatening signs. All patients with class III envenomation were referred to the intensive care unit, showing the importance of early identification of this subgroup. The main limitations were the small sample size and the fact that admission to intensive care was not based on systematic criteria. CONCLUSIONS: Point-of-care ultrasound is able to identify early signs of pulmonary congestion and heart failure in scorpionism. It can be useful for the objective selection of patients who are at a higher risk of complications and death and who require intensive support; it may also be valuable for periodic reassessments. Point-of-care ultrasound is a valuable tool for identifying and monitoring severe cases of scorpionism.

Understanding the complexity of Tityus serrulatus venom: A focus on high molecular weight components.

Tityus serrulatus scorpion is responsible for a significant number of envenomings in Brazil, ranging from mild to severe, and in some cases, leading to fatalities. While supportive care is the primary treatment modality, moderate and severe cases require antivenom administration despite potential limitations and adverse effects. The remarkable proliferation of T. serrulatus scorpions, attributed to their biology and asexual reproduction, contributes to a high incidence of envenomation. T. serrulatus scorpion venom predominantly consists of short proteins acting as neurotoxins (α and ß), that primarily target ion channels. Nevertheless, high molecular weight compounds, including metalloproteases, serine proteases, phospholipases, and hyaluronidases, are also present in the venom. These compounds play a crucial role in envenomation, influencing the severity of symptoms and the spread of venom. This review endeavors to comprehensively understand the T. serrulatus scorpion venom by elucidating the primary high molecular weight compounds and exploring their potential contributions to envenomation. Understanding these compounds' mechanisms of action can aid in developing more effective treatments and prevention strategies, ultimately mitigating the impact of scorpion envenomation on public health in Brazil.

Understanding the complexity of Tityus serrulatus venom: A focus on high molecular weight components

Tityus serrulatus scorpion is responsible for a significant number of envenomings in Brazil, ranging from mild to severe, and in some cases, leading to fatalities. While supportive care is the primary treatment modality, moderate and severe cases require antivenom administration despite potential limitations and adverse effects. The remarkable proliferation of T. serrulatus scorpions, attributed to their biology and asexual reproduction, contributes to a high incidence of envenomation. T. serrulatus scorpion venom predominantly consists of short proteins acting as neurotoxins (α and ß), that primarily target ion channels. Nevertheless, high molecular weight compounds, including metalloproteases, serine proteases, phospholipases, and hyaluronidases, are also present in the venom. These compounds play a crucial role in envenomation, influencing the severity of symptoms and the spread of venom. This review endeavors to comprehensively understand the T. serrulatus scorpion venom by elucidating the primary high molecular weight compounds and exploring their potential contributions to envenomation. Understanding these compounds' mechanisms of action can aid in developing more effective treatments and prevention strategies, ultimately mitigating the impact of scorpion envenomation on public health in Brazil.

Analysis of antibodies avidity for Tityus serrulatus scorpion venom in antivenom production and its potential for application as a potency test.

Antivenoms are the only specific medication for neutralizing toxins present in venom of animals such scorpions and snakes through antigen-antibody binding. Several analyses are carried out throughout its production in order to ensure the quality and effectiveness of the antivenom that will be administered to the patient. One of these is the potency assay, which is performed to assess the ability of antivenoms to neutralize the toxic effects of the venom injected in mice. The substitution of in vivo for in vitro assays such as ELISA has been presented by other authors, bringing several advantages such as the reduction in the use of animals, in costs and in the duration of the assays. However, the avidity index of antivenom antibodies determined by ELISA has not yet been applied for this purpose. Therefore, the objective of this study was to evaluate the avidity of sera from hyperimmunized horses with crude Tityus serrulatus venom, a scorpion species associated with the most serious accidents in Brazil, and its potential for application as a potency test replacing the in vivo assay. The avidity ELISA proved to be interesting for monitoring the binding strength of antibodies produced by horses in hyperimmune plasma production programs. It was possible to verify oscillations in antibody avidity that occurred along the immunization cycles, differences between novice and veteran horses, maturation of antibody avidity, and correlation between avidity index and antibody titre. Similar results were obtained for crude venom and purified Ts1 toxin. In addition, the avidity ELISA apparently demonstrated potential for application as a potency test in the initial stage of antivenom production. However, more studies are necessary.

Mitochondrial swelling in cardiomyocytes: Insights from a murine model of Tityus serrulatus scorpion envenomation.

Immune system hyperactivation is involved with clinical severity and pathological alterations during scorpion envenomation. In a murine model, mice inoculated with a lethal dose of Tityus serrulatus scorpion venom presented mitochondrial swelling in cardiomyocytes, with other structures such as sarcomeres and intercalated disks preserved. Treatment with dexamethasone or knockout animals to the interleukin-1ß receptor do not undergo mitochondrial changes in cardiomyocytes during envenomation.

Lipidomic profiling of the Brazilian yellow scorpion venom: new insights into inflammatory responses following Tityus serrulatus envenomation.

Due to the high prevalence and clinical relevance, scorpionism is a critical public health issue in several Brazilian regions. Tityus serrulatus, commonly known as the Brazilian yellow scorpion, is the most venomous genus found in Brazilian fauna and associated with severe clinical manifestations such as localized pain, hypertension, sweating, tachycardia and complex hyperinflammatory responses. In general, T. serrulatus venom contains a complex mixture of active compounds, including proteins, peptides, and amino acids. Although knowledge of the protein fractions of scorpion venom is available, venom lipid components are not yet comprehensively known. The aim of the present study was to determine and characterize the lipid constituents/profile of the T. serratus venom utilizing liquid chromatography coupled with high-resolution mass spectrometry. Lipid species (164 in total) belonging to 3 different lipid categories, glycerophospholipids, sphingolipids, and glycerolipids, were identified. A further search on MetaCore/MetaDrug platform, which is based upon a manually curated database of molecular interactions, molecular pathways, gene-disease associations, chemical metabolism, and toxicity information, exhibited several metabolic pathways for 24 of previously identified lipid species, including activation of nuclear factor kappa B and oxidative stress pathways. Further several bioactive compounds, such as plasmalogens, lyso-platelet-activating factors, and sphingomyelins, associated with systemic responses triggered by T. serrulatus envenomation were detected. Finally, lipidomic data presented provide advanced and valuable information to better comprehend the mechanisms underlying the complex pathophysiology induced by T. serrulatus envenomation.

Ts17, a Tityus serrulatus ß-toxin structurally related to α-scorpion toxins.

Ts17 was purified from the venom of the scorpion Tityus serrulatus, the most dangerous scorpion species in Brazil. The activity on Nav1.1-Nav1.7 channels was electrophysiologically characterized by patch-clamp technique. Ts17 amino acid sequence indicated high similarity to alpha-scorpion toxins; however, it presented beta-toxin activity, altering the kinetics of the Na+-channels. The most affected subtypes during activation (with and without prepulse) and inactivation phases were Nav1.2 and Nav1.5, respectively. For recovery from inactivation, the most affected voltage-gated sodium channel was Nav1.5. Circular dichroism spectra showed that Ts17 presents mainly ß-sheet and unordered structures at all analyzed pHs, and the maximum value of α-helix was found at pH 4.0 (13.3 %). Based on the results, Ts17 might be used as a template to develop a new cardiac drug. Key contribution Purification of Ts17 from Tityus serrulatus, electrophysiological characterization of Ts17 on voltage-gated sodium channel subtypes, ß-toxin classification.

Evolution of the occurrence of Tityus serrulatus (LUTZ & MELLO, 1992) in the state of Santa Catarina

ABSTRACT Background: Scorpions are a leading cause of envenomation in Brazil. The species Tityus serrulatus is associated with the most severe cases, especially in children. Despite not being endemic to the state of Santa Catarina, such occurrences have increased more than 500% in the state recently. Therefore, this study aimed to analyze the occurrence of envenomation by T. serrulatus, attended by the Center for Toxicological Information and Assistance of Santa Catarina. Methods: This was a retrospective and descriptive study of the occurrence of T. serrulatus, identified by the agency, from 2014 to 2021 in Santa Catarina, using data obtained by the BI-DATATOX system. Results: A total of 112 occurrences were classified as envenomation. Of these cases, 48.2% were recorded in the Itajaí Valley region and 33% in Greater Florianópolis. Men were involved in 59.8% of these, and the most common age group was 20-39 years (39.3%). Most envenomation occurred in urban areas (89.3%) under non-occupational circumstances (83%). Stings were more frequent on the hands (50.9%). Care was sought within 1 h after the event in 75.9% of the cases, and 94.6% were classified as mild. Conclusions: Occurrence of envenomation involving T. serrulatus in Santa Catarina increased significantly during the study period. Most cases occurred in urbanized areas, which suggests that they might have been transported from other states, and it must be considered that, in the urban environment, scorpions find a large supply of food and shelter and a reduced number of specific predators, allied to parthenogenesis.

Heterologous expression of Ts8, a neurotoxin from Tityus serrulatus venom, evidences its antifungal activity.

In this study we expressed the Ts8, a neurotoxin from Tityus serrulatus scorpion venom, in Pichia pastoris yeast. We evaluated the peptide expression in different conditions, such as pH, temperature, and addition of casamino acids supplement. Analyses of expressed products by mass spectrometry and Edman degradation showed that rTs8 has sites that allow its cleavage by yeast proteases released into the culture medium. The casamino acids addition was favourable for toxin expression, however, was not sufficient to minimize proteolytic degradation. Functional assays with recombinant toxin fragments and native toxins have demonstrated the release of cytokines such as TNF-α and IL-1ß in some peptides tested. In addition, the toxins were shown to inhibit the Pichia pastoris growth in antifungal test and were not toxic to alveolar macrophages cells at the concentrations analyzed The electrophysiological screening, by voltage clamp technique, showed that the rTs8 fragment with the highest molecular weight inhibited the Kv1.3 channel, whereas the N-terminal fragment had no activity on the ion channels tested.

Back to Tityus serrulatus Lutz & Mello, 1922 (Scorpiones: Buthidae): new comments about an old species.

A synopsis on the historical, geographical and ecological aspects related to the most conspicuous scorpion species of the genus Tityus known from Brazil is proposed. Tityus serrulatus Lutz & Mello, 1922 was described precisely one century ago, nevertheless many questions related to its ecological adaptations and geographical expansion remain without a precise response. This species, well known for its infamous reputation of noxious species, is also known for its capacity to reproduce asexually, by parthenogenesis. Although the individuals of a given population are considered clones, a new hypothesis could suggest the occurrence of mutations within isolated individuals, leading to distinct subpopulations that could present better phenotypic performances in ecological habitats distinct from those of the original area of distribution of the species.

Detection of areas vulnerable to scorpionism and its association with environmental factors in São Paulo, Brazil.

Accidents caused by scorpions are considered a neglected condition and represent a major health problem in most tropical countries, especially for children and elderly people. In Brazil, scorpionism is recurrent in the southeast region, mainly in the state of São Paulo, due to the progressive increase in scorpions found in urban habitats. Thus, our study aimed to provide better insights into the geographic and epidemiological characteristics of scorpion envenomation in São Paulo state and identify the environmental factors that are associated with these accidents. This is an ecological and retrospective study with secondary data on scorpion accidents in the state of São Paulo from 2008 to 2018 obtained from the Notifiable Disease Information System. The SatScan software was used to identify the higher- and lower-risk spatiotemporal clusters. A total of 145,464 scorpion sting cases were recorded in the state of São Paulo, between 2008 and 2018; there was a four-fold increase in the incidence rate. Accidents occurred more frequently in the spring season, wherein higher-risk clusters were in the north and northwest regions of the state. High temperatures, low precipitation, and poor natural vegetation are associated with higher risk areas. Our study mapped vulnerable areas for scorpion accidents that can aid in the design of efficient public health policies, which should be intensified during the spring season.

Back to Tityus serrulatus Lutz & Mello, 1922 (Scorpiones: Buthidae): new comments about an old species

A synopsis on the historical, geographical and ecological aspects related to the most conspicuous scorpion species of the genus Tityus known from Brazil is proposed. Tityus serrulatus Lutz & Mello, 1922 was described precisely one century ago, nevertheless many questions related to its ecological adaptations and geographical expansion remain without a precise response. This species, well known for its infamous reputation of noxious species, is also known for its capacity to reproduce asexually, by parthenogenesis. Although the individuals of a given population are considered clones, a new hypothesis could suggest the occurrence of mutations within isolated individuals, leading to distinct subpopulations that could present better phenotypic performances in ecological habitats distinct from those of the original area of distribution of the species.(AU)

Detection of areas vulnerable to scorpionism and its association with environmental factors in São Paulo, Brazil

Accidents caused by scorpions are considered a neglected condition and represent a major health problem in most tropical countries, especially for children and elderly people. In Brazil, scorpionism is recurrent in the southeast region, mainly in the state of São Paulo, due to the progressive increase in scorpions found in urban habitats. Thus, our study aimed to provide better insights into the geographic and epidemiological characteristics of scorpion envenomation in São Paulo state and identify the environmental factors that are associated with these accidents. This is an ecological and retrospective study with secondary data on scorpion accidents in the state of São Paulo from 2008 to 2018 obtained from the Notifiable Disease Information System. The SatScan software was used to identify the higher- and lower-risk spatiotemporal clusters. A total of 145,464 scorpion sting cases were recorded in the state of São Paulo, between 2008 and 2018; there was a four-fold increase in the incidence rate. Accidents occurred more frequently in the spring season, wherein higher-risk clusters were in the north and northwest regions of the state. High temperatures, low precipitation, and poor natural vegetation are associated with higher risk areas. Our study mapped vulnerable areas for scorpion accidents that can aid in the design of efficient public health policies, which should be intensified during the spring season.

Utilização de analgesia no teste de dose letal 50% do veneno de Tityus serrulatus

Acidentes com animas peçonhentos são de grande importância no mundo todo. No Brasil os estados mais afetados são Minas Gerais, São Paulo e Bahia, e mais da metade desses acidentes ocorrem por picadas de escorpiões. Contando com mais de 160 espécies no país, o principal responsável por tais acidentes é o Titys serrulatus. A melhor forma de tratamento para ocorrências com esses animais é a utilização do soro, que é produzido a partir do sangue de cavalos imunizados com o veneno. Para que um produto como esse seja utilizado pela população, ele deve ser aprovado pela Agência Nacional de Vigilância Sanitária (ANVISA). Que solicita uma série de testes a serem realizados, como por exemplo testes de esterilidade, pH, proteínas, atividades e potência in vitro e in vivo. Para executar o teste de potência, primeiro é preciso determinar a dose letal 50% do veneno. É sabido que o veneno é composto principalmente por neurotoxinas que acarretam diversas alterações clínicas além de poder levar a morte. Os animais utilizados em tais estudos estão em constante sofrimento e, assim, o objetivo desse estudo foi testar dois potentes analgésicos como forma de melhorar o bem-estar animal sem, é claro, alterar o resultado do teste. O estudo foi dividido em três grupos experimentais: controle; tramadol e morfina. Os animais receberam o analgésico 15 minutos antes do início do teste. Este estudo mostrou uma pequena melhora nos sintomas causados pelo envenenamento, ou seja, promoveu um maior conforto aos animais que receberam tratamento analgésicos, muito embora seja necessário realizar mais testes para refinar a técnica.

New Insights into the Hypotensins from Tityus serrulatus Venom: Pro-Inflammatory and Vasopeptidases Modulation Activities.

The Tityus serrulatus scorpion is considered the most dangerous of the Brazilian fauna due to the severe clinical manifestations in injured victims. Despite being abundant components of the venom, few linear peptides have been characterized so far, such as hypotensins. In vivo studies have demonstrated that hypotensin I (TsHpt-I) exerts hypotensive activity, with an angiotensin-converting enzyme (ACE)-independent mechanism of action. Since experiments have not yet been carried out to analyze the direct interaction of hypotensins with ACE, and to deepen the knowledge about these peptides, hypotensins I and II (TsHpt-II) were studied regarding their modulatory action over the activities of ACE and neprilysin (NEP), which are the peptidases involved in blood pressure control. Aiming to search for indications of possible pro-inflammatory action, hypotensins were also analyzed for their role in murine macrophage viability, the release of interleukins and phagocytic activity. TsHpt-I and -II were used in kinetic studies with the metallopeptidases ACE and NEP, and both hypotensins were able to increase the activity of ACE. TsHpt-I presented itself as an inhibitor of NEP, whereas TsHpt-II showed weak inhibition of the enzyme. The mechanism of inhibition of TsHpt-I in relation to NEP was defined as non-competitive, with an inhibition constant (Ki) of 4.35 µM. Concerning the analysis of cell viability and modulation of interleukin levels and phagocytic activity, BALB/c mice's naïve macrophages were used, and an increase in TNF production in the presence of TsHpt-I and -II was observed, as well as an increase in IL-6 production in the presence of TsHpt-II only. Both hypotensins were able to increase the phagocytic activity of murine macrophages in vitro. The difference between TsHpt-I and -II is the residue at position 15, with a glutamine in TsHpt-I and a glutamic acid in TsHpt-II. Despite this, kinetic analyzes and cell assays indicated different actions of TsHpt-I and -II. Taken together, these results suggest a new mechanism for the hypotensive effects of TsHpt-I and -II. Furthermore, the release of some interleukins also suggests a role for these peptides in the venom inflammatory response. Even though these molecules have been well studied, the present results suggest a new mechanism for the hypotensive effects of TsHpt-I.

Tityus serrulatus (Scorpion): From the Crude Venom to the Construction of Synthetic Peptides and Their Possible Therapeutic Application Against Toxoplasma gondii Infection.

Toxoplasmosis, caused by Toxoplasma gondii, is a major public concern owing to its neurotropic nature and high morbidity and mortality rates in immunocompromised patients and newborns. Current treatment for this disease is inefficient and produces side effects. Inflammatory mediators produced during T. gondii infection (e.g., cytokines and nitric oxide) are crucial in controlling parasite replication. In this context, Tityus serrulatus venom (TsV) induces the production of inflammatory mediators by immune cells. Thus, this study aimed to isolate and identify the components of TsV with potential anti-T. gondii activity. TsV was extracted from scorpions and lyophilized or loaded onto a column to obtain its fractions. TsV subfractions were obtained using chromatography, and its amino acid sequence was identified and applied to peptide design using bioinformatics tools. The C57BL/6 mice and their harvested macrophages were used to test the anti-Toxoplasma activity of TsV components and peptides. TsV and its fraction F6 attenuated the replication of tachyzoites in macrophages and induced nitric oxide and cytokine (IL-12, TNF, and IL-6) production by infected cells, without host cell toxicity. Moreover, Su6-B toxin, a subfraction of F6, demonstrated anti-T. gondii activity. The partially elucidated and characterized amino acid sequence of Sub6-B demonstrated 93% similarity with T. serrulatus 2 toxin (Ts2). Ts2 mimetic peptides ("Pep1," "Pep2a," and "Pep2b") were designed and synthesized. Pep1 and Pep2a, but not Pep2b, reduced the replication of tachyzoites in macrophages. In vivo, treatment of T. gondii-infected mice with Pep1, Pep2a, or Pep2b decreased the number of cerebral cysts and did not induce hepatotoxicity in the animals. Taken together, our data show promising immunomodulatory and antiparasitic activity of TsV that could be explored and applied in future therapies for treating infectious parasitic diseases such as toxoplasmosis.

Tityus serrulatus scorpion venom as a potential drug source for Chagas' disease: Trypanocidal and immunomodulatory activity.

Current chemical therapies for Chagas Disease (CD) lack ability to clear Trypanosoma cruzi (Tc) parasites and cause severe side effects, making search for new strategies extremely necessary. We evaluated the action of Tityus serrulatus venom (TsV) components during Tc infection. TsV treatment increased nitric oxide and pro-inflammatory cytokine production by Tc-infected macrophages (MØ), decreased intracellular parasite replication and trypomastigotes release, also triggering ERK1/2, JNK1/2 and p38 activation. Ts7 demonstrated the highest anti-Tc activity, inducing high levels of TNF and IL-6 in infected MØ. TsV/Ts7 presented synergistic effect on p38 activation when incubated with Tc antigen. KPP-treatment of MØ also decreased trypomastigotes releasing, partially due to p38 activation. TsV/Ts7-pre-incubation of Tc demonstrated a direct effect on parasite decreasing MØ-trypomastigotes releasing. In vivo KPP-treatment of Tc-infected mice resulted in decreased parasitemia. Summarizing, this study opens perspectives for new bioactive molecules as CD-therapeutic treatment, demonstrating the TsV/Ts7/KPP-trypanocidal and immunomodulatory activity during Tc infection.

New insights into the Hypotensins from Tityus serrulatus venom: pro-inflammatory and vasopeptidases modulation activities

The Tityus serrulatus scorpion is considered the most dangerous of the Brazilian fauna due to the severe clinical manifestations in injured victims. Despite being abundant components of the venom, few linear peptides have been characterized so far, such as hypotensins. In vivo studies have demonstrated that hypotensin I (TsHpt-I) exerts hypotensive activity, with an angiotensin-converting enzyme (ACE)-independent mechanism of action. Since experiments have not yet been carried out to analyze the direct interaction of hypotensins with ACE, and to deepen the knowledge about these peptides, hypotensins I and II (TsHpt-II) were studied regarding their modulatory action over the activities of ACE and neprilysin (NEP), which are the peptidases involved in blood pressure control. Aiming to search for indications of possible pro-inflammatory action, hypotensins were also analyzed for their role in murine macrophage viability, the release of interleukins and phagocytic activity. TsHpt-I and -II were used in kinetic studies with the metallopeptidases ACE and NEP, and both hypotensins were able to increase the activity of ACE. TsHpt-I presented itself as an inhibitor of NEP, whereas TsHpt-II showed weak inhibition of the enzyme. The mechanism of inhibition of TsHpt-I in relation to NEP was defined as non-competitive, with an inhibition constant (Ki) of 4.35 μM. Concerning the analysis of cell viability and modulation of interleukin levels and phagocytic activity, BALB/c mice’s naïve macrophages were used, and an increase in TNF production in the presence of TsHpt-I and -II was observed, as well as an increase in IL-6 production in the presence of TsHpt-II only. Both hypotensins were able to increase the phagocytic activity of murine macrophages in vitro. The difference between TsHpt-I and -II is the residue at position 15, with a glutamine in TsHpt-I and a glutamic acid in TsHpt-II. Despite this, kinetic analyzes and cell assays indicated different actions of TsHpt-I and -II. Taken together, these results suggest a new mechanism for the hypotensive effects of TsHpt-I and -II. Furthermore, the release of some interleukins also suggests a role for these peptides in the venom inflammatory response. Even though these molecules have been well studied, the present results suggest a new mechanism for the hypotensive effects of TsHpt-I

Self-Assembled Cationic-Covered Nanoemulsion as A Novel Biocompatible Immunoadjuvant for Antiserum Production Against Tityus serrulatus Scorpion Venom.

This study assesses the efficacy of different nanoemulsion formulations as new and innovative adjuvants for improving the in vivo immunization against the Tityus serrulatus scorpion venom. Nanoemulsions were designed testing key-variables such as surfactants, co-solvents, and the influence of the temperature, which would be able to induce the phase transition from a liquid crystal to a stable nanoemulsion, assessed for four months. Additionally, cationic-covered nanoemulsion with hyper-branched poly(ethyleneimine) was prepared and its performance was compared to the non-cationic ones. The physicochemical properties of the selected nanoemulsions and the interactions among their involved formulation compounds were carefully monitored. The cytotoxicity studies in murine macrophages (RAW 264.7) and red blood cells were used to compare different formulations. Moreover, the performance of the nanoemulsion systems as biocompatible adjuvants was evaluated using mice immunization protocol. The FTIR shifts and the zeta potential changes (from -18.3 ± 1.0 to + 8.4 ± 1.4) corroborated with the expected supramolecular anchoring of venom proteins on the surface of the nanoemulsion droplets. Cell culture assays demonstrated the non-toxicity of the formulations at concentrations less than 1.0 mg/mL, which were able to inhibit the hemolytic effect of the scorpion venom. The cationic-covered nanoemulsion has shown superior adjuvant activity, revealing the highest IgG titer in the immunized animals compared to both the non-cationic counterpart and the traditional aluminum adjuvant. In this approach, we demonstrate the incredible potential application of nanoemulsions as adjuvants, using a nanotechnology platform for antigen delivery system on immune cells. Additionally, the functionalization with hyper-branched poly(ethyleneimine) enhances this recognition and improves its action in immunization.

Moving Pieces in a Cellular Puzzle: A Cryptic Peptide from the Scorpion Toxin Ts14 Activates AKT and ERK Signaling and Decreases Cardiac Myocyte Contractility via Dephosphorylation of Phospholamban.

Cryptic peptides (cryptides) are biologically active peptides formed after proteolysis of native precursors present in animal venoms, for example. Proteolysis is an overlooked post-translational modification that increases venom complexity. The tripeptide KPP (Lys-Pro-Pro) is a peptide encrypted in the C-terminus of Ts14-a 25-mer peptide from the venom of the Tityus serrulatus scorpion that has a positive impact on the cardiovascular system, inducing vasodilation and reducing arterial blood pressure of hypertensive rats among other beneficial effects. A previous study reported that KPP and its native peptide Ts14 act via activation of the bradykinin receptor B2 (B2R). However, the cellular events underlying the activation of B2R by KPP are unknown. To study the cell signaling triggered by the Ts14 cryptide KPP, we incubated cardiac myocytes isolated from C57BL/6 mice with KPP (10-7 mol·L-1) for 0, 5, or 30 min and explored the proteome and phosphoproteome. Our results showed that KPP regulated cardiomyocyte proteins associated with, but not limited to, apoptosis, muscle contraction, protein turnover, and the respiratory chain. We also reported that KPP led to AKT phosphorylation, activating AKT and its downstream target nitric oxide synthase. We also observed that KPP led to dephosphorylation of phospholamban (PLN) at its activation sites (S16 and T17), leading to reduced contractility of treated cardiomyocytes. Some cellular targets reported here for KPP (e.g., AKT, PLN, and ERK) have already been reported to protect the cardiac tissue from hypoxia-induced injury. Hence, this study suggests potential beneficial effects of this scorpion cryptide that needs to be further investigated, for example, as a drug lead for cardiac infarction.