Effect of Tityus serrulatus venom on cytokine production and the activity of murine macrophages

Yellow scorpion (Buthus sinidicus) venom peptides induce mitochondrial-mediated apoptosis in cervical, prostate and brain tumor cell lines

Scorpion venoms are known to contain over 100,000 biologically active constituents. However, only a few of them have been studied. The major constituents of venom are proteins and peptides, which exhibit various biological and pharmacological properties, including anticancer activities. In the current study, the venom of yellow scorpions (Buthus sindicus) found in Sindh, Pakistan, was extracted and evaluated for its anti-cancer and anti-inflammatory activities. The crude venom showed a dose dependent inhibition of phagocyte oxidative burst from human whole blood cells (28.3% inhibition at highest tested concentration of 300 μg/mL). In-vitro cytotoxicity of crude venom was evaluated against human prostrate (PC3), cervical (HeLa) and neuroblastoma (U87-MG) cell lines, along with cytotoxicity against normal human fibroblast (BJ) cells. Crude venom was cytotoxic to all cell lines, with prominent inhibitory effect on PC3 cells. Crude venom was fractionated through RP-UPLC, resulted in fifteen fractions, followed by evaluation of their anticancer potential. Among all, the fraction I significantly (P < 0.001) reduced the cell viability of all three cancer cell lines, and exhibited insignificant cytotoxicity against normal cell line. Furthermore, the apoptotic cell death pathway was evaluated for crude venom, and fraction I, in most sensitive cell line PC3, by using flow-cytometry analysis. Both crude venom and its fraction I caused a mitochondrial-mediated apoptosis in prostate cancer cells (PC3). To the best of our knowledge, this is the first report of the anticancer and anti-inflammatory activity of venom of Pakistani yellow scorpions. Results indicate their therapeutic potential, and a case for further purification and validation studies.

TanP: A Multifunctional Anionic Peptide From Tityus stigmurus Scorpion Venom

Anionic peptides of scorpions are molecules rich in aspartic and/or glutamic acid residues and correspond to a class of peptides without disulfide bonds that are still little explored. TanP is a linear anionic peptide (50 amino acid residues and net charge -20) present in the venom gland of the scorpion, Tityus stigmurus, with chelating properties for Cu2+ ion and immunomodulatory properties. The therapeutic application of chelating molecules is related to cases of acute or chronic intoxication by metals, neurodegenerative diseases, hematological diseases, healing of skin wounds, cardiovascular diseases, and cancer. In this approach, the chelating activity of TanP was evaluated in relation to new metal ions (Fe2+ and Zn2+) of biological importance, as well as its antioxidant, hemostatic, immunomodulatory, and healing potential, aiming to expand the biological and biotechnological potential of this peptide. TanP (25 µM) was able to form stable complexes with Fe2+ in a ratio of 1:5 (TanP: Fe2+). Theoretical results suggest that TanP can work as a sensor to identify and quantify Fe2+ ions. The fluorescence intensity of TanP (1.12 µM) decreased significantly after the addition of Fe2+, obtaining the highest ratio 1: 7.4 (TanP: Fe2+) that led to the lowest fluorescence intensity. For Zn2+, no relevant spectral change was noted. TanP (50 µM) showed a maximum of 3% of hemolytic activity, demonstrating biocompatibility, as well as exhibiting a 1,1-diphenyl-2-picrylhydrazyl radical-scavenging activity of above 70% at all the concentrations tested (1-25 μM), and 89.7% iron-chelating activity at 25 μM and 96% hydroxyl radical-scavenging activity at 73.6 μM. In addition, TanP (12.5 and 25 µM) revealed an anticoagulant effect, prolonging the clotting time in prothrombin time and activated partial thromboplastin time assays, with no fibrinogenolytic activity. TanP (12.5 and 25 µM) induced the release of TNF-α by murine macrophages, in the absence of lipopolysaccharides, with a concentration-dependent increase and also stimulated the migration of 3T3 cells in the in vitro healing assay. Thus, TanP revealed a multifunctional potential, being useful as a prototype for the development of new therapeutic and biotechnological agents.

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.

Macrophage activation in vitro by Parachartergus fraternus venom

Parachartergus fraternus wasp induces inflammation with a predominance of mononuclear cells, that can acquire macrophage functions at the sting site, amplifying the response. These cells can be activated by venomous animals and are involved in destruction of injurious agents and release of inflammatory mediators. The objective of this work was to evaluate the activity of P. fraternus venom (Pfv) on isolated murine macrophage function. The cells were obtained from peritoneal cavity of Swiss male mice and incubated with Pfv (2.5, 5 and 10 μg/mL). Cytotoxicity was determined using MTT assay. Adhesion and detachment were evaluated using violet crystal dye. Spreading was evaluated based on morphological parameters. Phagocytosis was performed with opsonized zymosan. Production of hydrogen peroxide (H₂O₂) and nitric oxide (NO) were quantified using the phenol red and Griess assays, respectively. Pfv at concentrations evaluated was not cytotoxic in MTT assay and did not cause macrophage detachment in cell culture plates. However, it increased adhesion of macrophage, spreading and phagocytosis of opsonized zymosan, as well as induced production of H₂O₂ and NO. Therefore, Pfv induces macrophage activation in vitro and the response of these cells can be correlated with the previously reported inflammatory process triggered by this wasp.

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.

EP80317 Restrains Inflammation and Mortality Caused by Scorpion Envenomation in Mice

Over 1 million cases of scorpion stings are estimated every year, whereas current treatment is limited to antivenom serum combined with supportive therapy. Tityus serrulatus scorpion venom (TsV) is composed of diverse molecules, including toxins that induce a catecholamine storm and mediate classical symptoms of scorpion envenomation. However, the same toxins promote an intense inflammatory response coordinated by innate immune cells, such as macrophages, contributing significantly to the lung edema and mortality caused by TsV injection. Macrophages sense TsV via innate immune receptors, including TLR2, TLR4, and CD14 that promote inflammation and mortality via PGE₂/cAMP/PKA/NF-κB/IL-1β axis. The scavenger receptor CD36 also recognizes TsV, but in contrast to the other receptors, it drives the production of leukotriene B₄ (LTB₄). This lipid mediator operates via BLT1 receptor to reduce cAMP production and consequently IL-1β release, which results in resistance to fatal outcomes of experimental scorpion envenomation. EP80317 is an hexapeptide that serves as a ligand for CD36 and features protective effects under conditions such as atherosclerosis and vascular inflammation. In this study, we evaluated the effects of EP80317 treatment during experimental scorpion envenomation. EP80317 treatment suppressed mouse peritoneal macrophage production of IL-1β, IL-6, tumor necrosis factor (TNF-α), CCL3, and PGE₂ in vitro. EP80317 treatment also boosted the production of LTB₄ and IL-10 in response to TsV. Importantly, EP80317 restrained lung inflammation and mortality caused by TsV in vivo. Taken together, these data indicate a strong therapeutic potential of EP80317 as a supportive treatment to control inflammation induced by scorpion envenomation.

Scorpion Venom Causes Upregulation of p53 and Downregulation of Bcl-xL and BID Protein Expression by Modulating Signaling Proteins Erk1/2 and STAT3, and DNA Damage in Breast and Colorectal Cancer Cell Lines

Scorpion venoms efficiently block the normal neurotransmitter signaling pathway by prejudicing the ion channel operating mechanism in the body system. Besides its negative effect, venoms also possess some beneficial qualities for humans. They have also been shown to exhibit anticancer properties in various cancer types. This unique property of the venom as an anticancer agent is mainly a result of its role in initiating apoptosis and inhibiting several signaling cascade mechanisms that promote cancer cell proliferation and growth. In this study, we examine the effect of venom on phenotypic changes as well as changes at the molecular levels in colorectal and breast cancer cell lines. A dramatic decrease in cell invasion was observed in both cancer cell lines on venom treatment. Additionally, there was decrease in IL-6, RhoC, Erk1/2, and STAT3 in venom-treated cell lines, providing strong evidence of its anticancer properties. Furthermore, decrease in the expression of antiapoptotic proteins and also upregulation of proapoptotic ones by these lines were observed on venom treatment. Moreover, a vivid picture of DNA damage was also detected on venom treatment. In conclusion, scorpion venom possesses significant potential as an anticancer agent against colorectal and breast cancer cell lines.

In vitro analysis of the anticancer properties of scorpion venom in colorectal and breast cancer cell lines

Scorpion venom contains various types of proteins and peptides that are able to act as inhibitors of neurotransmitter molecules. This is achieved primarily via the inhibition of ion channels. In addition, scorpion venom has been demonstrated to exhibit anticancer properties in prostate and breast cancer, as well as leukemia. The anticancer properties of scorpion venom are due to its inhibitory effect on matrix metalloproteinase (MMP) activity, which leads to reduced motility and invasion in tumor cells. The inhibitory effects of venom on MMPs additionally lead to a reduction in the metastatic potential of malignant tumors. In the present study, the effect of venom obtained from a local serpentarium facility was examined in colorectal and breast cancer cell lines. Cell motility and clonogenic survival assays revealed a significant decrease (60-90%) in cell motility and colony formation, two significant hallmarks of cancer survival, following treatment with various concentrations of venom. These results were in agreement with previous studies demonstrating the anticancer activity of scorpion venom. In conclusion, the venom utilized at the Research Center of Prince Sultan Military Medical City Hospital (Riyadh, Saudi Arabia) possesses significant anticancer potential against colorectal and breast cancer cell lines.

Tityus serrulatus venom--A lethal cocktail

Tityus serrulatus (Ts) is the main scorpion species of medical importance in Brazil. Ts venom is composed of several compounds such as mucus, inorganic salts, lipids, amines, nucleotides, enzymes, kallikrein inhibitor, natriuretic peptide, proteins with high molecular mass, peptides, free amino acids and neurotoxins. Neurotoxins are considered the most responsible for the envenoming syndrome due to their pharmacological action on ion channels such as voltage-gated sodium (Nav) and potassium (Kv) channels. The major goal of this review is to present important advances in Ts envenoming research, correlating both the crude Ts venom and isolated toxins with alterations observed in all human systems. The most remarkable event lies in the Ts induced massive releasing of neurotransmitters influencing, directly or indirectly, the entire body. Ts venom proved to extremely affect nervous and muscular systems, to modulate the immune system, to induce cardiac disorders, to cause pulmonary edema, to decrease urinary flow and to alter endocrine, exocrine, reproductive, integumentary, skeletal and digestive functions. Therefore, Ts venom possesses toxins affecting all anatomic systems, making it a lethal cocktail. However, its low lethality may be due to the low venom mass injected, to the different venom compositions, the body characteristics and health conditions of the victim and the local of Ts sting. Furthermore, we also described the different treatments employed during envenoming cases. In particular, throughout the review, an effort will be made to provide information from an extensive documented studies concerning Ts venom in vitro, in animals and in humans (a total of 151 references).

Revealing the Function and the Structural Model of Ts4: Insights into the "Non-Toxic" Toxin from Tityus serrulatus Venom

The toxin, previously described as a "non-toxic" toxin, was isolated from the scorpion venom of Tityus serrulatus (Ts), responsible for the most severe and the highest number of accidents in Brazil. In this study, the subtype specificity and selectivity of Ts4 was investigated using six mammalian Nav channels (Nav1.2→Nav1.6 and Nav1.8) and two insect Nav channels (DmNav1 and BgNav). The electrophysiological assays showed that Ts4 specifically inhibited the fast inactivation of Nav1.6 channels, the most abundant sodium channel expressed in the adult central nervous system, and can no longer be classified as a "non-toxic peptide". Based on the results, we could classify the Ts4 as a classical α-toxin. The Ts4 3D-structural model was built based on the solved X-ray Ts1 3D-structure, the major toxin from Ts venom with which it shares high sequence identity (65.57%). The Ts4 model revealed a flattened triangular shape constituted by three-stranded antiparallel β-sheet and one α-helix stabilized by four disulfide bonds. The absence of a Lys in the first amino acid residue of the N-terminal of Ts4 is probably the main responsible for its low toxicity. Other key amino acid residues important to the toxicity of α- and β-toxins are discussed here.

Serological, biochemical and enzymatic alterations in rodents after experimental envenomation with Hadruroides lunatus scorpion venom

Toxic effects of Peruvian Hadruroides lunatus scorpion venom on different biochemical and enzymatic parameters in blood serum of Wistar rats and Swiss mice were determined after experimental envenomation. An increase in enzymatic activities of Aspartate Aminotransferase (AST), Lactate Dehydrogenase (LDH) and levels of serum protein and albumin were observed while a decrease in creatinine level in serum was perceived after 30 min of envenomation. No alterations in urea levels and in kidney histology were detected in the envenomed rats. The global leukocytes count was diminished, with decrease in lymphocytes, eosinophils and neutrophils levels in the bloodstream, while no alterations were found in hematological parameters of red series in rats injected with H. lunatus venom. IL-2, IL-4, IL-6, INF-γ, TNF, IL-17A and IL-10 levels were evaluated 0.5, 3 and 6 h after experimental envenomation of mice with H. lunatus venom. From all the analyzed cytokines, only IL-6 showed an increase in serum levels. Taken together, these results point out that envenomation by H. lunatus can impair hematological and immunological parameters and therefore might be monitored in accidents involving this species.

Electrophysiological characterization of the first Tityus serrulatus alpha-like toxin, Ts5: Evidence of a pro-inflammatory toxin on macrophages

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.

Neutralizing effects of Mimosa tenuiflora extracts against inflammation caused by Tityus serrulatus scorpion venom

Scorpion bite represents a significant and serious public health problem in certain regions of Brazil, as well as in other parts of the world. Inflammatory mediators are thought to be involved in the systemic and local immune response induced by Tityus serrulatus scorpion envenomation. The aim of this study was to evaluate the effect of extracts of Mimosa tenuiflora on model envenomation. In mice, the envenomation model is induced by Tityus serrulatus venom. Previous treatment of mice with fractions from M. tenuiflora was able to suppress the cell migration to the peritoneal cavity. The treatment of mice with M. tenuiflora extracts also decreased the levels of IL-6, IL-12, and IL-1β. We concluded that the administration of the extract and fractions resulted in a reduction in cell migration and showed a reduction in the level of proinflammatory cytokines. This study demonstrates, for the first time, the anti-inflammatory effect of aqueous extract from the Mimosa tenuiflora plant on T. serrulatus venom.

Effects of Buthus martensii Karsch Venom on Cell Proliferation and Cytotoxicity in Hela Cells

This paper focuses on the effect of the venom of the scorpion Buthus martensii on the proliferation of human cervical carcinoma Hela cell line and the related molecular mechanism. MTT test showed that the scorpion venom inhibited proliferation of Hela cells in time-dependent and concentration-dependent manner with 50% inhibitory concentration (IC50) of 34.5 μg/mL(48 h). By using flow cytometry, it was found that the scorpion venom could induce apoptosis and necrosis in Hela cells. RT-PCR and Western blot indicated there were obviously up-regulated in the expressions of p21 protein but the expression of p21 mRNA showed no significant difference in the Hela cell by the scorpion venom. These results suggest that the possible mechanism of the scorpion venom is to activate the expressions of p21 protein and to cause Hela cell apoptosis.

Immune cells recruitment and activation by Tityus serrulatus scorpion venom

Despite several studies showed that the Tityus serrulatus scorpion venom (Tsv) induces an inflammatory response, just a few have investigated the effect of the venom on the immune response. Therefore, the aim of this study was to evaluate alterations of venom application on lymphoid organs and on the recruitment and activation of cells and also on the cytokine production. Swiss male mice (2-3 months, 20-25 g) received a non-lethal dose of crude Tsv (200 μg/kg), diluted in sterile PBS by subcutaneous route. Control animals received only sterile PBS. The animals were sacrificed after 30, 120 and 360 min. The inflammatory parameters studied were skin histology at the site of venom application, leukocyte count, and blood cytokine levels (IL-6, IL-10, and TNF-α). Inguinal lymph node, spleen and bone marrow cellularity was determined for evaluation of the Tsv effect on immune system organs. The results showed that Tsv caused no local inflammation, but it induced an increase of blood neutrophils and serum IL-6, TNF-α and IL-10. After 360 min of envenomation there was a reduction in the cells number from peritoneum and spleen, but there was an increase in the cell number from lymph nodes. In conclusion, the Tsv induces systemic alterations characterized by changes in the cell number in lymphoid organs, increase pro and anti-inflammatory cytokines.

Tityus serrulatus venom and toxins Ts1, Ts2 and Ts6 induce macrophage activation and production of immune mediators

Scorpion envenomation induces a systemic immune response, and neurotoxins of venom act on specific ion channels, modulating neurotransmitter release or activity. However, little is known about the immunomodulatory effects of crude venom from scorpion Tityus serrulatus (TsV) or its toxins (Ts1, Ts2 and Ts6) in combination with lipopolysaccharide (LPS). To investigate the immunomodulatory effects of TsV and its toxins (Ts1, Ts2 and Ts6), J774.1 cells were stimulated with different concentrations (25, 50 and 100 μg/mL) of venom or toxins pre-stimulated or not with LPS (0.5 μg/mL). Macrophage cytotoxicity was assessed, and nitric oxide (NO) and cytokine production were analyzed utilizing the culture supernatants. TsV and its toxins did not produce cytotoxic effects. Depending on the concentrations used, TsV, Ts1 and Ts6 stimulated the production of NO, interleukin (IL)-6 and tumor necrosis factor (TNF)-α in J774.1 cells, which were enhanced under LPS co-stimulation. However, LPS + Ts2 inhibited NO, IL-6 and TNF-α production, and Ts2 alone stimulated the production of IL-10, suggesting an anti-inflammatory activity for this toxin. Our findings are important for the basic understanding of the mechanisms involved in macrophage activation following envenomation; additionally, these findings may contribute to the discovery of new therapeutic compounds to treat immune-mediated diseases.

Specific activation of human neutrophils by scorpion venom: a flow cytometry assessment

Acute lung injury following envenomation by Tityus scorpion species is due in part to activation of the inflammatory response leading to release of cytotoxic leukocyte-derived products, including cytokines and possibly reactive oxygen species (ROS). Tityus zulianus envenomation in Venezuela produces cardiorespiratory complications and death by lung injury whereas stings by Tityus discrepans produce mainly gastrointestinal and pancreatic alterations. To ascertain the role played by granulocytes in the envenomation by T. zulianus (TzV) and T. discrepans (TdV), human peripheral blood neutrophils, eosinophils, and monocytes were exposed to scorpion venoms (0.001-5 μg/mL) and the kinetics (5-15 min) of peroxide production determined by flow cytometry, using 2',7'-dichlorodihydrofluorescein diacetate (succinimidyl ester) as a fluorescent substrate. TzV induced a significantly (p<0.01) more potent increase in peroxide production in neutrophils (for 5 and 10 min of incubation), and to a lesser extent in monocytes (5-15 min), compared to TdV. TzV induced necrosis in neutrophils at doses higher than 5 μg/mL. No effect was observed on eosinophils, suggesting that TzV specifically targets neutrophil intracellular ROS production. The TzV-stimulated pathway is protein kinase C-dependent because it was almost completely (>90%) abolished by staurosporine. The stimulatory effect is associated with the lowest molecular mass venom peptides as gel filtration fractions TzII and TzIII significantly enhanced peroxide production. The combined used of the intracellular ROS agonist, phorbol myristate acetate (PMA), and TzV produced a modest but significant increase in peroxide production suggesting the possibility of overlapping signaling cascades amongst PMA and TzV. Up-regulation of intracellular neutrophil ROS production may be an important in vivo target for TzV which could have a role to play in the cardiorespiratory complications elicited after envenomation by this species.

Scorpion venom and the inflammatory response

Scorpion venoms consist of a complex of several toxins that exhibit a wide range of biological properties and actions, as well as chemical compositions, toxicity, and pharmacokinetic and pharmacodynamic characteristics. These venoms are associated with high morbility and mortality, especially among children. Victims of envenoming by a scorpion suffer a variety of pathologies, involving mainly both sympathetic and parasympathetic stimulation as well as central manifestations such as irritability, hyperthermia, vomiting, profuse salivation, tremor, and convulsion. The clinical signs and symptoms observed in humans and experimental animals are related with an excessive systemic host inflammatory response to stings and stings, respectively. Although the pathophysiology of envenomation is complex and not yet fully understood, venom and immune responses are known to trigger the release of inflammatory mediators that are largely mediated by cytokines. In models of severe systemic inflammation produced by injection of high doses of venom or venoms products, the increase in production of proinflammatory cytokines significantly contributes to immunological imbalance, multiple organ dysfunction and death. The cytokines initiate a cascade of events that lead to illness behaviors such as fever, anorexia, and also physiological events in the host such as activation of vasodilatation, hypotension, and increased of vessel permeability.

Macrophage activation, phagocytosis and intracellular calcium oscillations induced by scorpion toxins from Tityus serrulatus

The research described here is focused upon studying the activation of mice peritoneal macrophages when submitted to in vitro effects of Tityus serrulatus scorpion venom and its major toxic peptides. Several functional events were analysed, such as: cytotoxicity, spreading, extent of phagocytosis, vacuole formation and changes of internal calcium concentration. Among the main results observed, when macrophages are subjected to the effects of soluble venom of Tityus serrulatus scorpion venom, a partially purified fraction (FII) or a pure toxin (Ts1), are an increment in the percentage of phagocytosis and vacuole formation, a decrement of the spreading ability, accompanied by oscillations of internal calcium concentration. The net results demonstrate that scorpion venom or its major toxins are effective stimulators of macrophage activity; the effect of whole soluble venom or partially purified fractions is due to the toxic peptides, seen here clearly with Ts1. The possible involvement of Na+-channels in these events is discussed. A basic understanding of the underlying molecular mechanisms responsible for macrophage activation should serve as a foundation for novel drug development aimed at modulating macrophage activity.

Edematogenic activity of scorpion venoms from the Buthidae family and the role of platelet-activating factor and nitric oxide in paw edema induced by Tityus venoms

We compared the edematogenic activity of venoms of scorpions from the Buthidae family, Tityus bahiensis (Tbv), Tityus serrulatus (Tsv) and Rhopalurus rochai (Rrv). Three doses (20, 40 and 80 microg/kg sc) of each venom were administrated in hind paw of mice and edema was measured from 5 min to 24 h. Tbv and Tsv both induced edema of rapid onset (135% of increase at 15 min); Rrv induced only a mild edema (40% of increase). We then investigated the involvement of platelet-activating factor (PAF) and endogenous nitric oxide (NO) in Tbv and Tsv-induced paw edema. Pretreatment of mice with a PAF antagonist (WEB-2170) inhibited Tsv but not Tbv-induced edema. Pretreatment with a non selective inhibitor of NO-synthases (L: -NAME) inhibited or increased the edema depending on the dose and the time the edema was measured. In conclusion, the venoms from Tityus are stronger inducers of edema than the venom from the Rhopalurus scorpion. The venoms of Tityus species are similar in potency and time-course edema development. PAF is involved in the edema induced only by Tsv.

Scorpion venom polypeptide accelerate irradiated hematopoietic cells proliferation

OBJECTIVE

To study the effects of Scorpion venom polypeptide (SVP) on the irradiated hematopoietic progenitor cells and the initial research of its mechanism.

METHODS AND MATERIALS

(1) MTT array was used to select the effective concentration of SVP that had proliferate action on the irradiated early hematopoietic cells (K562), just like the doses of experiment in vitro; (2) The male BALB/c mice were divided into NS control group, SVP IV group and SVP V group. After treatment and sublethal irradiation, the C-KIT and IL-6Ralpha levels of bone marrow cells were detected by immunohistochemistry and tissue array; (3) The bone marrow cells of the normal BALB/c mice, given to SVP IV and SVP V after different action times respectively, were taken to extract the total proteins inside the cell, the phosphorylated STAT3 protein levels in JAK-STAT signal transduction pathway were detected by Western blot array.

RESULTS

(1) 30mg/L SVP IV has an obvious effect to accelerate K562 cell proliferation; (2) The C-KIT and IL-6Ralpha expression on bone marrow cell surfaces in SVP IV and SVP V groups were negative (control with the saline group, p>0.05); (3) The phosphorylated STAT3 protein levels in bone marrow cells of SVP IV group had a rise-and-fall trend within 30min, while the test of SVP V group showed that the phosphorylated STAT3 protein levels obviously elevated after 30min.

CONCLUSIONS

The results show that certain SVP IV concentration can protect the hematopoietic progenitor cells after irradiation, and the underlying mechanism of SVP accelerating the hematopoietic recovery in irradiated mice may be related to the activation of the JAK-STAT signal pathway.

Toxin gamma from Tityus serrulatus scorpion venom plays an essential role in immunomodulation of macrophages

Fraction number II obtained from Sephadex G-50 gel filtration of the soluble venom from the Brazilian scorpion Tityus serrulatus (TSV) stimulates macrophage function in vitro. The aim of this study was to identify which one of the several components of this fraction was responsible for the main stimulatory activity on macrophages. This component was identified as sub-fraction II-11, also known by the name of gamma toxin or simply abbreviated Ts1, which stands for toxin 1 of T. serrulatus venom. The effect of Ts1 was analyzed by detection of inflammatory mediators. Several functional bioassays were performed: TNF activity was assayed by measuring its cytotoxicity on L929 cells, whereas IL-1, IL-6, IFN-gamma and IL-10 were assayed by enzyme-linked immunosorbent assay. The levels of NO were evaluated by Griess colorimetric reactions in supernatants of macrophages in culture exposed to Ts1 and compared with FII. Macrophages exposed to Ts1 increase the production of mediators. With respect to the pro-inflammatory cytokines, an increment of IL-1alpha, IL-1beta was observed after 12 h; the maximum levels of IL-6 and TNF were observed after 24 h; the highest levels of IFN-gamma and NO were observed after 72 h. In contrast, the highest levels of anti-inflammatory cytokines such as IL-10 were observed after 120 h. With respect to the balance of pro- and anti-inflammatory cytokines, IL-1alpha/IL-10 and IL-6/IL-10 ratios appear incremented between 12 and 48 h in macrophages exposed to Ts1. IL-1beta/IL-10 and TNF/IL-10 ratios were increased in macrophages exposed to Ts1 for 12 h. IFN-gamma/IL-10 ratios increased up to 48 h, decaying thereafter. Elevated IL-6/TNF ratios were observed up to 24 h. These ratios may possibly reflect the inflammatory status during exposition to the venom. In conclusion, these data indicate that Ts1 has an important immunomodulatory effect on macrophages, and add important knowledge for understanding scorpion envenomation. It also opens the field for further research about the intoxication phenomenon as it is discussed here.

Scorpion venom increases mRNA expression of lung cytokines

Previous studies have demonstrated that scorpion toxins increase the serum levels of IL-1, IL-6, INF-gamma, and GM-CSF in patients with severe shock and pulmonary edema. Moreover, it has been shown that experimental models of scorpion envenomation presented an increase in serum levels of IL-1, IL-6, IFN-gamma and nitric oxide. Thus, it is possible that the cytokine release may contribute to the onset and maintenance of the pulmonary edema induced by scorpion venom. This study was designed to investigate whether inflammatory and non-inflammatory cytokines, contribute to the pulmonary injury induced by infusion of Tityus serrulatus scorpion toxin in rats. We show that scorpion venom not only increases the expression of mRNA pulmonary inflammatory cytokines but also non-inflammatory cytokines as well. Moreover, the expression of IL-1alpha, IL-1beta and IL-6 mRNA was shown to be higher among the remaining detectable cytokines. The findings of this study provide additional insight towards the understanding of the pathophysiology of the pulmonary edema induced by scorpion venom. The increased level of pulmonary cytokines observed during the pulmonary edema may be responsible for the exacerbation and maintenance of the inflammatory response to scorpion venom in the lungs.

Immunomodulatory effects of the Tityus serrulatus venom on murine macrophage functions in vitro

Tityus serrulatus scorpion venom (TSV) consists of a very complex mixture of molecules and demonstrates significant immunomodulatory activities capable of stimulating immune functions in vivo. The purpose of this study was to compare the crude TSV with fractionated toxins extracted from this venom in order to determine which toxin(s) presented immunomodulatory effects on peritoneal macrophages. TSV was fractionated using gel filtration chromatography resulting in 5 heterogeneous fractions. The effects of these different fractions were analysed in vitro using detection by means of cytokines, oxygen intermediate metabolites (H2O2), and nitric oxide (NO) in supernatants of peritoneal macrophages. Several functional bioassays were employed: tumor necrosis factor (TNF) activity was assayed by measuring its cytotoxic activity in L929 cells, and other cytokines were assayed by enzyme-linked immunosorbent assay, whereas NO levels were detected by Griess colorimetric reactions in culture supernatant of macrophages exposed to different fractions. In vitro studies revealed that all fractions studied here presented an increment in H2O2, NO , and cytokines levels. The more pronounced increments were observed in macrophage cultures exposed to fraction FII which demonstrated that (a) the highest levels of IL-1alpha, IL-beta, and TNF were observed after 12 hours and that (b) the maximum levels of IFN-gamma and NO were observed after 72 hours. Taken together, these data indicate that fractions have a differential immunomodulating effect on macrophage secretion, and that FII is a potent activator of TNF production of macrophages.

Time course of acute-phase response induced by Tityus serrulatus venom and TsTX-I in mice

Animal venom can induce systemic alterations similar to those observed in acute-phase inflammatory response. In the present study, we report the systemic (circulatory) and local (peritoneal cavity) effects induced by Tityus serrulatus venom and its major toxin TsTX-I (Ts1) in mice over various time periods. Both the venom and TsTX-I elicited quite similar responses in most assays. Responses included reduction of albumin, increased C-reactive protein, IL-6, IL-1alpha and TNF-alpha. Local and systemic leucocytosis, with a predominance of polymorphonuclear cells, was also observed. These effects show that a systemic inflammation-like syndrome is triggered during the severe envenomation caused by the T. serrulatus sting. The initial increases of albumin and total protein were probably consequences of the dehydration that occurs at the beginning of envenomation. Time-course analysis of these effects shows that responses are most pronounced on the first day after poisoning. However, leucocytosis and changes in acute-phase protein concentrations can be observed up to 7 days after envenomation.

Effect of Venom from the Scorpion Leiurus Quinquestriatus on Rat Vascular Aortic Rings

The present study was designed to examine the effects of venom from the scorpion Leiurus quinquestriatus hebraeus (Lqh) on the contractility of rat aortic rings. We first examined the effect of Lqh venom on the contractile tension of isolated rat vascular aortic rings and then whether long-term exposure to the venom reduces the contractility of vascular smooth muscle by increasing the production of nitric oxide. Following the administration of 33 microg/mL of crude Lqh venom, contractile tension increased by 18.9 +/- 11.4 percent. The administration of 2.4 x 10(-7) M noradrenaline (NA) led to a 31.6 +/- 8.2 percent increase in tension (p < 0.01). The effects induced by NA and Lqh venom were similar and additive (p < 0.01). Pretreatment with the alpha-adrenergic blocker phenoxybenzamine (0.2 microM) eliminated the effect of the venom, whereas the calcium-channel blocker verapil (8.3 microM) merely attenuated the effect. Incubation of the rings with Lqh venom for 16 to 18 h, followed by NA stimulation, led to a 15 to 20 percent decrease in tension (p < 0.001). Treatment with N-omega-nitro-L-arginine methyl ester (110 microM), a constitutional nitric oxide inhibitor, restored the tension to control values. Treatment with S-methyl-isothiourea (0.1 microM), an inducible nitric oxide synthesis inhibitor, had no effect on contractile tension. The results of the present study suggest that the effect of Lqh venom on isolated aortic rings is induced via sympathetic nerve terminals. Calcium had little effect on the smooth muscle contractility of aortic rings incubated with the venom. No evidence was found to support nitric oxide synthesis after the long-term exposure of the rings to Lqh venom.

The dynamics of cytokine d nitric oxide secretion in mice injected with Tityus serrulatus scorpion venom

AIMS

The effects of Tityus serrulatus venom (TSV) were analysed with respect to the susceptibility of four isogenic mouse, the symptoms following injection of venom and the inflammatory mediators in an experimental model of severe envenomation induced in mice.

METHODS

The susceptibility was analysed by lethal dose (LD50) determination, including the symptoms observed during envenomating and glucose levels. The detection of cytokines in serum from mice were analysed using enzyme-linked immunosorbent assay, and nitric oxide (NO) was analysed using nitrite determination.

RESULTS

The estimated LD50 values were in micrograms per 100 microliters, and the susceptibility of mice to TSV varies with: (a) mouse strain and route of injection (A/J < BALB/c < C57Bl/6 = DBA); (b) mouse strain and sex (A/J female and male < BALB/c female and male); and (c) body weight (all groups of A/J < BALB/c groups). Among the mouse strains studied, BALB/c mice presented moderate sensibility to TSV, with changes in specific signs and serum levels of glucose, several cytokines and NO, when injected intraperitoneally (i.p.) with 1 LD50 of venom. Sweating, salivation and tremor were the specific signs that preceded death. The maximum levels of glucose in sera from mice injected i.p. with 1 LD50 of TSV were observed 60-90 min post-injection. Significant differences were observed in the time-course of cytokine levels, and the venom induced marked elevations of interleukin (IL)-1alpha, IL-1beta, IL-6, IL-10 and interferon gamma (IFN-gamma). The maximum levels of IL-1alpha and IL-1beta were observed 2 h post-injection. The more pronounced levels of IL-6 were observed 4 h post-injection. There was an early increase in IFN-gamma followed by an even higher level after 4 h. IL-10 levels peaked between 6 and 8 h, and this cytokine probably modulates the secretion of IFN-gamma. Tumor necrosis factor release was not detected in BALB/c mice injected with TSV. NO levels attained maximal release after 2 h, following venom injection, while a second peak for NO was at 6 h.

CONCLUSIONS

These findings indicate that the susceptibility to the systemic effects of the venom varies among mice of different haplotypes, and that the cytokines such as IL-1, IL-6, IFN-gamma and NO are strongly involved in the pathogenesis caused by this venom and are correlated with the severity of envenomation.