Southern African scorpion toxins: An overview

Profiling the Linear Peptides of Venom from the Brazilian Scorpion Tityus serrulatus: Structural and Functional Characterization

Scorpion venoms are a rich source of bioactive peptides, most of which are neurotoxic, with 30 to 70 amino acid residues in their sequences. There are a scarcity of reports in the literature concerning the short linear peptides found in scorpion venoms. This type of peptide toxin may be selectively extracted from the venom using 50% (v/v) acetonitrile. The use of LC-MS and MS/MS enabled the detection of 12 bioactive short linear peptides, of which six were identified as cryptides. These peptides were shown to be multifunctional, causing hemolysis, mast cell degranulation and lysis, edema, pain, and anxiety, increasing the complexity of the envenomation mechanism. Apparently, the natural functions of these peptide toxins are to induce inflammation and discomfort in the victims of scorpion stings.

A Relationship Between Clinical and Laboratory Characteristics in Children With Severe Scorpion Envenomation in Çukurova, Turkey

OBJECTIVE

Scorpion stings are an important health problem in many parts of the world. The aim of this study was to retrospectively examine cases of scorpion stings to evaluate their epidemiological, clinical, and laboratory features and to determine strategies that can reduce morbidity and mortality in these cases.

METHODS

Scorpion stings experienced by children between 2007 and 2013 were retrospectively reviewed. The patients were categorized into groups based on severities of toxicities, and demographic, clinical, and laboratory features were compared between the groups.

RESULTS

The mean ± SD age of the 189 patients with scorpion stings was 83.43 ± 59.62 months. There was a significant difference between the clinical stages and the age distribution of the cases (P < 0.05). White blood cell counts differed significantly between the groups (P < 0.05). There was not a significant difference in mean platelet volume and platelet distribution width between the groups, but plateletcrit and low platelet count were significantly different between stage 1 and stage 3 cases (P < 0.05). Glucose, creatinine kinase-myoglobin binding, and troponin I were also significantly different (P < 0.05). The mortality rate was 0%.

CONCLUSIONS

People living in regions where scorpion stings are frequent should be informed about preventive measures against these stings, cases of scorpion stings should be monitored in appropriate centers, and staff offering care to these cases should be educated about treatment methods. In addition, treatment protocols should be determined in accordance with regions where the stings occur and studies should be performed to describe prognostic indicators.

Australian Scorpion Hormurus waigiensis Venom Fractions Show Broad Bioactivity Through Modulation of Bio-Impedance and Cytosolic Calcium

Scorpion venoms are a rich source of bioactive molecules, but characterisation of toxin peptides affecting cytosolic Ca2+, central to cell signalling and cell death, is limited. We undertook a functional screening of the venom of the Australian scorpion Hormurus waigiensis to determine the breadth of Ca2+ mobilisation. A human embryonic kidney (HEK293) cell line stably expressing the genetically encoded Ca2+ reporter GCaMP5G and the rabbit type 1 ryanodine receptor (RyR1) was developed as a biosensor. Size-exclusion Fast Protein Liquid Chromatography separated the venom into 53 fractions, constituting 12 chromatographic peaks. Liquid chromatography mass spectroscopy identified 182 distinct molecules with 3 to 63 components per peak. The molecular weights varied from 258 Da-13.6 kDa, with 53% under 1 kDa. The majority of the venom chromatographic peaks (tested as six venom pools) were found to reversibly modulate cell monolayer bioimpedance, detected using the xCELLigence platform (ACEA Biosciences). Confocal Ca2+ imaging showed 9/14 peak samples, with molecules spanning the molecular size range, increased cytosolic Ca2+ mobilization. H. waigiensis venom Ca2+ activity was correlated with changes in bio-impedance, reflecting multi-modal toxin actions on cell physiology across the venom proteome.

Anti-Nociceptive and Anti-Inflammation Effect Mechanisms of Mutants of Syb-prII, a Recombinant Neurotoxic Polypeptide

Syb-prII, a recombinant neurotoxic polypeptide, has analgesic effects with medicinal value. Previous experiments indicated that Syb-prII displayed strong analgesic activities. Therefore, a series of in vivo and vitro experiments were designed to investigate the analgesic and anti-inflammatory properties and possible mechanisms of Syb-prII. The results showed that administered Syb-prII-1 and Syb-prII-2 (0.5, 1, 2.0 mg/kg, i.v.) to mice significantly reduced the time of licking, biting, or flicking of paws in two phases in formalin-induced inflammatory nociception. Syb-prII-1 inhibited xylene-induced auricular swelling in a dose-dependent manner. The inhibitory effect of 2.0 mg/kg Syb-prII-1 on the ear swelling model was comparable to that of 200 mg/kg aspirin. In addition, the ELISA and Western blot analysis suggested that Syb-prII-1 and Syb-prII-2 may exert an analgesic effect by inhibiting the expression of Nav1.8 and the phosphorylation of ERK, JNK, and P38. Syb-prII-1 markedly suppressed the expression of IL-1β, IL-6, and TNF-α of mice in formalin-induced inflammatory nociception. We used the patch-clamp technique and investigated the effect of Syb-prII-1 on TTX-resistant sodium channel currents in acutely isolated rat DRG neurons. The results showed that Syb-prII-1 can significantly down regulate TTX-resistant sodium channel currents. In conclusion, Syb-prII mutants may alleviate inflammatory pain by significantly inhibiting the expression of Nav1.8, mediated by the phosphorylation of MAPKs and significant inhibition of TTX-resistant sodium channel currents.

Biodegradable cross-linked chitosan nanoparticles improve anti-Candida and anti-biofilm activity of TistH, a peptide identified in the venom gland of the Tityus stigmurus scorpion

Among several bioactive peptides identified from the venom glands of the Tityus stigmurus scorpion, one peptide with hypotensive action (TistH, Tityus stigmurus Hypotensin) showed multifunctional and biotechnological applications. The maximum efficacy of this class of compounds can be achieved by immobilizing it in specific and suitable biomaterials or suitable carriers. In this study, distinct entrapment methods of TistH in chitosan nanoparticles was tested using its incorporation (CN-TistH-Inc) or adsorption (CN-TistH-Ads) methods by ionotropic gelification. Physico-chemical properties as well as biocompatibility and antifungal efficacy were assessed for different samples. Atomic force microscopy and field emission gun scanning electronic microscopy images associated with particle size measurements demonstrated that the two methods induced cationic spherical, small (< 160 nm), and narrow-sized (PdI about 0.3) nanoparticles, even after peptide loading greater than 96.5%, which was confirmed using Fourier transform infrared spectroscopy. The colloidal suspensions showed to be stable for 8 weeks and were able to induce the desired slow in vitro peptide release. Cytotoxicity assays performed in normal cells originated from murine macrophages (RAW 264.7) and kidneys of African green monkeys (Vero E6) suggested biocompatibility of samples. The CN-TistH-Inc and CN-TistH-Ads showed a minimal inhibitory concentration of 89.2 μg.mL^-1 against Candida albicans, 11.1 μg.mL^-1 for C. parapsilosis and C. tropicalis, confirmed by minimum fungicidal concentrations assay. Moreover, the TistH-loaded cross-linked chitosan nanoparticles significantly reduced the biofilm formation of clinical yeast sepsis of C. tropicalis and C. krusei, as well as clinical yeasts of vulvovaginal candidiasis of C. albicans. In this approach, biodegradable nanocarriers prepared using simple and reproducible methods demonstrated the ability to deliver the TistH peptide from T. stigmurus and improve its antifungal efficacy.

Approach to scorpion stings in pregnancy: A retrospective case series and literature review

OBJECTIVE

Scorpion stings remain a serious health problem in many parts of the world. There is very limited information regarding the effects of therapies delivered for scorpion stings in pregnant women on the mother and fetus. They can cause acute conditions such as fetal loss, preterm delivery, or placental abnormalities and can also result in other conditions that may have an effect on the baby in the long term.

MATERIALS AND METHODS

In this study the medical records of 24 pregnant women who were admitted to the emergency room at Suruç State Hospital due to scorpion stings between January 1, 2013 and January 1, 2014 were retrospectively reviewed. Age, gestational week, monthly distribution of the cases, type of delivery, status of the fetus, affected body sites, and local and systemic findings were evaluated. The clinical severity of each case was assessed using Abroug's classification. A fetal biophysical profile test was administered in pregnant women above 24 weeks of gestation. The newborns underwent follow-up for mental and motor functions in the pediatric department at three-month intervals for 12 months.

RESULTS

24 patients, with a mean age of 26.1 ± 2.4 years, were included in the study. The most common region stung by scorpions was Lower extremity (58.3%). The most common symptom occurred in cases was immediate localized pain (58%). In terms of gestational age, 41.6% of scorpion sting were within the third trimester. Biophysical profile scores were 8 and above. Only symptomatic treatment, without use of anti-venom, was done to all the patients in this study. And neither death nor major sequel happened.

CONCLUSION

Scorpion stings during pregnancy may not have significant adverse effects on the fetus and the mother. Decisions regarding the use of anti-venom in pregnant women should be considered carefully when only limited safety information, especially in those patients with only local symptoms.

"Saving Face": An Online Study of the Injecting Use of DIY Botox and Dermal Filler Kits

This study reports on an empirically underdocumented practice in contemporary aesthetic enhancement culture, the self-injection of unregulated DIY Botox and dermal filler kits purchased online. Data were collected from 4 online discussion forums containing disclosures in relation to use of DIY kits and analyzed using ethnographic content analysis. Motivation to source DIY Botox and dermal fillers online was grounded in desire to avoid financial cost of professional services and a lack of confidence in practitioners. Future intentions to order online raw materials and "formulas" to prepare dermal fillers at home were expressed. Individuals taught themselves to inject through watching YouTube tutorials and downloading Botox injection maps from the Internet. Although individuals demonstrated awareness of the health risks involved with self-injection of unregulated products, this was not a deterrent. Future research is warranted to document the injecting practices and health outcomes of individuals who inject DIY Botox and dermal filler kits to inform targeted harm reduction interventions by health-care practitioners.

Mesobuthus Venom-Derived Antimicrobial Peptides Possess Intrinsic Multifunctionality and Differential Potential as Drugs

Animal venoms are a mixture of peptides and proteins that serve two basic biological functions: predation and defense against both predators and microbes. Antimicrobial peptides (AMPs) are a common component extensively present in various scorpion venoms (herein abbreviated as svAMPs). However, their roles in predation and defense against predators and potential as drugs are poorly understood. Here, we report five new venom peptides with antimicrobial activity from two Mesobuthus scorpion species. These α-helical linear peptides displayed highly bactericidal activity toward all the Gram-positive bacteria used here but differential activity against Gram-negative bacteria and fungi. In addition to the antibiotic activity, these AMPs displayed lethality to houseflies and hemotoxin-like toxicity on mice by causing hemolysis, tissue damage and inducing inflammatory pain. Unlike AMPs from other origins, these venom-derived AMPs seem to be unsuitable as anti-infective drugs due to their high hemolysis and low serum stability. However, MeuTXKβ1, a known two-domain Mesobuthus AMP, is an exception since it exhibits high activity toward antibiotic resistant Staphylococci clinical isolates with low hemolysis and high serum stability. The findings that the classical AMPs play predatory and defensive roles indicate that the multifunctionality of scorpion venom components is an intrinsic feature likely evolved by natural selection from microbes, prey and predators of scorpions. This definitely provides an excellent system in which one can study how a protein adaptively evolves novel functions in a new environment. Meantimes, new strategies are needed to remove the toxicity of svAMPs on eukaryotic cells when they are used as leads for anti-infective drugs.

SVP-B5 peptide from Buthus martensii Karsch scorpion venom exerts hyperproliferative effects on irradiated hematopoietic cells

Previous studies have demonstrated the radioprotective efficacy of scorpion venom peptide, fraction II (SVPII) from the venom of Buthus martensii Karsch. In the present study, the SVP-B5 polypeptide, which is one of the active components of SVPII, was purified using a two-step chromatographic process. SVP-B5 significantly promoted the proliferation of irradiated M-NFS-60 mouse-derived myelocytic leukemia cells. In addition, SVP-B5 effectively and persistently promoted hematopoietic recovery and expansion of hematopoietic cells after irradiation as demonstrated by cobblestone area forming cell and long-term bone marrow culture assays. Treatment of M-NFS-60 cells with SVP-B5 upregulated the expression of interleukin 3 receptor and activated the Janus kinase-2/signal transducer and activator of transcription 5 signaling pathway. In conclusion, the present study demonstrated that SVP-B5 has growth factor-like properties and may be used as a therapeutic modality in the recovery of severe myelosuppression, which is a common side effect of radiotherapy.

Adaptive evolution of insect selective excitatory β-type sodium channel neurotoxins from scorpion venom

Insect selective excitatory β-type sodium channel neurotoxins from scorpion venom (β-NaScTxs) are composed of about 70-76 amino acid residues and share a common scaffold stabilized by four unique disulfide bonds. The phylogenetic analysis of these toxins was hindered by limited sequence data. In our recent study, two new insect selective excitatory β-NaScTxs, LmIT and ImIT, were isolated from Lychas mucronatus and Isometrus maculatus, respectively. With the sequences previously reported, we examined the adaptive molecular evolution of insect selective excitatory β-NaScTxs by estimating the nonsynonymous-to-synonymous rate ratio (ω=d_N/d_S). The results revealed 12 positively selected sites in the genes of insect selective excitatory β-NaScTxs. Moreover, these positively selected sites match well with the sites important for interacting with sodium channels, as demonstrated in previous mutagenesis study. These results reveal that adaptive evolution after gene duplication is one of the most important genetic mechanisms of scorpion neurotoxin diversification.

Scorpion toxin peptide action at the ion channel subunit level

This review categorizes functionally validated actions of defined scorpion toxin (SCTX) neuropeptides across ion channel subclasses, highlighting key trends in this rapidly evolving field. Scorpion envenomation is a common event in many tropical and subtropical countries, with neuropharmacological actions, particularly autonomic nervous system modulation, causing significant mortality. The primary active agents within scorpion venoms are a diverse group of small neuropeptides that elicit specific potent actions across a wide range of ion channel classes. The identification and functional characterisation of these SCTX peptides has tremendous potential for development of novel pharmaceuticals that advance knowledge of ion channels and establish lead compounds for treatment of excitable tissue disorders. This review delineates the unique specificities of 320 individual SCTX peptides that collectively act on 41 ion channel subclasses. Thus the SCTX research field has significant translational implications for pathophysiology spanning neurotransmission, neurohumoral signalling, sensori-motor systems and excitation-contraction coupling. This article is part of the Special Issue entitled 'Venom-derived Peptides as Pharmacological Tools.'

Characterization of TistH, a multifunctional peptide from the scorpion Tityus stigmurus: Structure, cytotoxicity and antimicrobial activity

The presence of bioactive peptides in animal venoms has been targeted in scientific research for assessing biological activities, as well as mechanisms of action. A recent study by our group observed hypotensive action of TistH (Tityus stigmurus Hypotensin), a peptide deduced from the transcriptome of T. stigmurus venom gland. The present study aims to analyze TistH structure properties and to evaluate its toxicity on normal and tumor cells, its in vitro antimicrobial activity, as well as its inflammatory effect. Circular dichroism analyses of TistH showed a general predominance of α-helix conformation in TFE (20-70%) and structural stability to pH variations. TistH was not cytotoxic to normal cell lines (3T3, RAW and HEK), and also not to cancer cell lines (HeLa, B16, 786-0, SiHa and HepG2). The peptide did not present inflammatory activity up to 6 h after administered subcutaneously to Swiss mice. It was observed that concentrations of 4-1024 μg/mL of TistH produced no inhibition against the bacteria Staphylococcus aureus, Staphylococcus epidermidis e Pseudomonas aeruginosa. The results of antifungal assays showed a moderate activity of TistH against Candida albicans strain LM-108 and the filamentous fungus Trichophyton rubrum LM-640, with growth inhibition at a concentration of 1024 μg/mL. In contrast, the peptide presented a greater activity (MIC 128 μg/mL) against C. albicans LM-106, Candida tropicalis ATCC 13308 and Aspergillus flavus strains LM-247 and LM-26, fungi that cause oral and vaginal infections, candidiasis and respiratory allergies, respectively. The present data contribute to a better understanding of TistH and its possible use as a bioactive compound. This multifunctional peptide is capable of acting as anti-hypertensive, as well as to inhibit the growth of fungal strains, having low toxicity, which suggests its safety for using as a pharmacological agent.

Scorpion sting nephropathy

Scorpion envenomations are ubiquitous, but nephropathy is a rare manifestation, reported mainly from the Middle East and North Africa. Rapid venom redistribution from blood, delayed excretion from the kidneys, direct toxicity of venom enzymes, cytokine release and afferent arteriolar constriction have been seen in experimental animals. Haemoglobinuria, acute tubular necrosis, interstitial nephritis and haemolytic–uraemic syndrome have been documented in human victims of scorpion envenomation. Epidemiology, venom components and toxins, effects on the laboratory mammals especially the kidneys and reports of renal failure in humans are reviewed in this article.

Evaluation of separation properties of a modified strong cation exchange material named MEX and its application in 2D-MEX × C18 system to separate peptides from scorpion venom

Peptides from scorpion venom represent one of the most promising sources for drug discovery in some specific disease.

Analgesic-antitumor peptide induces apoptosis and inhibits the proliferation of SW480 human colon cancer cells

Colorectal cancer is one of the most common malignant tumors, and is associated with significant morbidity and mortality. In this study, recombinant analgesic-antitumor peptide (rAGAP), a protein consisting of small ubiquitin-related modifier (SUMO) linked with a hexa-histidine tag, was used as an antitumor analgesic peptide. The purpose of the present study was to investigate the antitumor activity of rAGAP in human colon adenocarcinoma SW480 cells and its potential molecular mechanisms of action. In this study, cell viability and apoptosis of rAGAP-treated SW480 cells was evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, flow cytometry and 4′,6-diamidino-2-phenylindole (DAPI) staining. Western blotting was used to investigate the effects of rAGAP on p27, Bcl-2/Bax and PTEN/PI3K/Akt cellular signal transduction. Our results showed that rAGAP not only enhanced apoptosis, but also inhibited the proliferation of SW480 cells. rAGAP upregulates the expression of p27 in SW480 cells and leads to cell cycle arrest in the G1 phase. Furthermore, rAGAP significantly increases the production of Bax and PTEN and suppresses the activation of Bcl-2, phosphatidylinositol 3-kinase (PI3K) and phospho-Akt (p-Akt) in SW480 cells. These results suggest that rAGAP may be a potential new anti-colorectal cancer drug.

Investigating the chemical profile of regenerated scorpion (Parabuthus transvaalicus) venom in relation to metabolic cost and toxicity

We investigated the biochemical profile of regenerated venom of the scorpion Parabuthus transvaalicus in relation to its metabolic cost and toxicity. Using a closed-system respirometer, we compared oxygen consumption between milked and unmilked scorpions to determine the metabolic costs associated with the first 192 h of subsequent venom synthesis. Milked scorpions had a substantially (21%) higher mean metabolic rate than unmilked scorpions, with the largest increases in oxygen consumption occurring at approximately 120 h, 162 h, and 186 h post-milking. Lethality tests in crickets indicated that toxicity of the regenerated venom returned to normal levels within 4 d after milking. However, the chemical profile of the regenerated venom, as evaluated by FPLC and MALDI-TOF mass spectrometry, suggested that regeneration of different venom components was asynchronous. Some peptides regenerated quickly, particularly those associated with the scorpion's "prevenom," whereas others required much or all of this time period for regeneration. This asynchrony could explain the different spikes detected in oxygen consumption of milked scorpions as various peptides and other venom components were resynthesized. These observations confirm the relatively high metabolic cost of venom regeneration and suggest that greater venom complexity can be associated with higher costs of venom production.

Scorpion stings in Turkey: epidemiological and clinical aspects between the years 1995 and 2004

The most important health-threatening scorpions found in Turkey are; Androctonus crassicauda, Leiurus quinquestriatus, Mesobuthus gibbosus and M. eupeus species, all of which belong to the Buthidae family. The epidemiological and clinical findings of scorpion stings in Turkey were evaluated between the years 1995 and 2004 based on data recorded in the National Poison Information Center (NPIC). A total of 930 cases were recorded. The cases mostly occurred in the month of July. The gender distribution was 50.22% female and 45.48% male. It was shown that the 20-29 age group presented more scorpion stings. Most of the stings occurred in Central Anatolia and Marmara regions of Turkey. Patients at the hospital showed signs of localized (pain, hyperemia, edema and numbness) and systemic effects (hyperthermia, nausea and vomiting, tachycardia, shivering and lethargy) but no lethality was notified. According to records, 33% of the poisoned patients were treated with antivenin in healthcare facilities.

Drugs from slugs--past, present and future perspectives of omega-conotoxin research

Peptides from the venom of carnivorous cone shells have provided six decades of intense research, which has led to the discovery and development of novel analgesic peptide therapeutics. Our understanding of this unique natural marine resource is however somewhat limited. Given the past pharmacological record, future investigations into the toxinology of these highly venomous tropical marine snails will undoubtedly yield other highly selective ion channel inhibitors and modulators. With over a thousand conotoxin-derived sequences identified to date, those identified as ion channel inhibitors represent only a small fraction of the total. Here we discuss our present understanding of conotoxins, focusing on the omega-conotoxin peptide family, and illustrate how such a seemingly simple snail has yielded a highly effective clinical drug.

Parabutoporin, a cationic amphipathic peptide from scorpion venom: much more than an antibiotic

Parabutoporin (PP) from the South African scorpion Parabuthus schlechteri is a 45-mer lysine-rich and cysteine-free peptide. At micromolar concentrations it has antimicrobial effects against G+ and G- bacteria and is antifungal as well. However, at submicromolar concentrations, parabutoporin also directly interferes with cellular functions of the human innate immune system, especially polymorphonuclear neutrophils (PMN): parabutoporin acts as a chemoattractant for neutrophils, induces their degranulation, while delaying constitutive neutrophil apoptosis. In addition, it potently inhibits induced superoxide production. Different signalling pathways regulating these biochemical processes were identified as targets of parabutoporin. Therefore, parabutoporin is a well documented scorpion venom peptide with immuno-regulatory properties beyond its antibiotic effects.