Single domain von Willebrand factor type C "cytokines" and the regulation of the stress/immune response in insects

The single domain von Willebrand factor type C (SVWC) appears in small secreted peptides that are arthropod-specific and are produced following environmental stress or pathogen exposure. Most research has focused on proteins with SVWC domain that are induced after virus infection and are hypothesized to function as "cytokines" to regulate the innate immune response. The expansion of SVWC genes in insect species indicates that many other functions remain to be discovered. Research in shrimp has elucidated the adaptability of Vago-like peptides in the innate immune response against bacteria, fungi and viruses after activation by Jak-STAT and/or Toll/Imd pathways in which they can act as pathogen-recognition receptors or cytokine-like signaling molecules. SVWC factors also appear in scorpion venoms and tick saliva, underlining their versatility to acquire new functions. This review discusses the discovery and function of SVWC peptides from insects to crustaceans and chelicerates and reveals the enormous gaps in knowledge that remain to be filled to understand this enigmatic group of secreted peptides.

Identification of an Antimicrobial Peptide from the Venom of the Trinidad Thick-Tailed Scorpion Tityus trinitatis with Potent Activity against ESKAPE Pathogens and Clostridioides difficile

Envenomation by the Trinidad thick-tailed scorpion Tityus trinitatis may result in fatal myocarditis and there is a high incidence of acute pancreatitis among survivors. Peptidomic analysis (reversed-phase HPLC followed by MALDI-TOF mass spectrometry and automated Edman degradation) of T. trinitatis venom led to the isolation and characterization of three peptides with antimicrobial activity. Their primary structures were established asTtAP-1 (FLGSLFSIGSKLLPGVFKLFSRKKQ.NH2), TtAP-2 (IFGMIPGLIGGLISAFK.NH2) and TtAP-3 (FFSLIPSLIGGLVSAIK.NH2). In addition, potassium channel and sodium channel toxins, present in the venom in high abundance, were identified by CID-MS/MS sequence analysis. TtAP-1 was the most potent against a range of clinically relevant Gram-positive and Gram-negative aerobes and against the anaerobe Clostridioides difficile (MIC = 3.1-12.5 µg/mL). At a concentration of 1× MIC, TtAP-1 produced rapid cell death (<15 min against Acinetobacter baumannii and Staphylococcus aureus). The therapeutic potential of TtAP-1 as an anti-infective agent is limited by its high hemolytic activity (LC50 = 18 µg/mL against mouse erythrocytes) but the peptide constitutes a template for the design of analogs that maintain the high bactericidal activity against ESKAPE pathogens but are less toxic to human cells. It is suggested that the antimicrobial peptides in the scorpion venom facilitate the action of the neurotoxins by increasing the membrane permeability of cells from either prey or predator.

Scorpion Venom as a Source of Antimicrobial Peptides: Overview of Biomolecule Separation, Analysis and Characterization Methods

Scorpion venoms have long captivated scientific researchers, primarily due to the potency and specificity of the mechanism of action of their derived components. Among other molecules, these venoms contain highly active compounds, including antimicrobial peptides (AMPs) and ion channel-specific components that selectively target biological receptors with remarkable affinity. Some of these receptors have emerged as prime therapeutic targets for addressing various human pathologies, including cancer and infectious diseases, and have served as models for designing novel drugs. Consequently, extensive biochemical and proteomic investigations have focused on characterizing scorpion venoms. This review provides a comprehensive overview of the key methodologies used in the extraction, purification, analysis, and characterization of AMPs and other bioactive molecules present in scorpion venoms. Noteworthy techniques such as gel electrophoresis, reverse-phase high-performance liquid chromatography, size exclusion chromatography, and "omics" approaches are explored, along with various combinations of methods that enable bioassay-guided venom fractionation. Furthermore, this review presents four adapted proteomic workflows that lead to the comprehensive dissection of the scorpion venom proteome, with an emphasis on AMPs. These workflows differ based on whether the venom is pre-fractionated using separation techniques or is proteolytically digested directly before further proteomic analyses. Since the composition and functionality of scorpion venoms are species-specific, the selection and sequence of the techniques for venom analyses, including these workflows, should be tailored to the specific parameters of the study.

Identification and Venom Characterization of Two Scorpions from the State of Chihuahua Mexico: Chihuahuanus coahuliae and Chihuahuanus crassimannus

Chihuahua is the largest state in Mexico. The ecosystem of this region is composed of large area of bushes, forests, and grasslands, which allows for a specific diversity of fauna; among them are interesting species of non-lethal scorpions. Most of the Chihuahuan scorpions have been previously morphologically and molecularly described; however, this manuscript could be the first to describe the composition of those venoms. This work aimed at the collection of two scorpion species from the region of Jiménez (Southwest of the State of Chihuahua), which belong to the species Chihuahuanus cohauilae and Chihuahuanus crassimanus; the two species were taxonomically and molecularly identified using a 16S DNA marker. Reverse-phase high-performance liquid chromatography (RP-HPLC) of C. coahuilae and C. crassimanus venoms allowed the identification of three fractions lethal to mice. Additionally, three fractions of each scorpion displayed an effect on house crickets. In the end, three new fractions from the venom of C. coahuilae were positive for antimicrobial activity, although none from C. crassimanus venom displayed growth inhibition. Despite being a preliminary study, the venom biochemical analysis of these two uncharacterized scorpion species opens the opportunity to find new molecules with potential applications in the biomedical and biotechnological fields.

Characterization of a Family of Scorpion Toxins Modulating Ca(2+)-Activated Cl(-) Current in Vascular Myocytes

The pharmacology of calcium-activated chloride current is not well developed. Peptides from scorpion venom present potent pharmacological actions on ionic conductance used to characterize the function of channels but can also be helpful to develop organic pharmacological tools. Using electrophysiological recording coupled with calcium measurement, we tested the potent effect of peptides extracted from Leuirus quinquestratus quinquestratus venom on the calcium-activated chloride current expressed in smooth muscle cells freshly dissociated from rat portal veins. We identified one peptide which selectively inhibited the chloride conductance without effects on either calcium signaling or calcium and potassium currents expressed in this cell type. The synthetic peptide had the same affinity, but the chemical modification of the amino acid sequence altered the efficiency to inhibit the calcium-activated chloride conductance.

French Scorpionism (Mainland and Oversea Territories): Narrative Review of Scorpion Species, Scorpion Venom, and Envenoming Management

Sixty-seven scorpion species have been described in France and its territories, where they have been found to be heterogeneously distributed. Indeed, only one species can be found on Réunion Island, while 38 species exist in French Guiana. The number of stings is also heterogenous, with up to 90 stings per 100,000 inhabitants occurring annually. Scorpion species can frequently be determined through simple visual factors, including species of medical importance (i.e., Buthus, Centruroides and Tityus). Scorpion venom is composed of local enzymes and peptides with a cysteine-stabilized α/β motif (NaTxs, Ktxs, Calcines), which allow for venom diffusion and the prey's incapacitation, respectively. Harmful scorpion species are limited to Centruroides pococki in the French West Indies, which can induce severe envenoming, and the Tityus obscurus and Tityus silvestris in French Guiana, which can cause fatalities in children and can induce severe envenoming, respectively. Envenomation by one of these scorpions requires hospital monitoring as long as systemic symptoms persist. Typical management includes the use of a lidocaine patch, pain killers, and local antiseptic. In the case of heart failure, the use of dobutamine can improve survival, and pregnant women must consult an obstetrician because of the elevated risk of preterm birth or stillbirth. France does not have scorpion antivenom, as scorpion stings are generally not fatal.

Molecular dynamics simulation analysis of alpha-cobra toxin docked with phytochemical compounds

It is of interest to document data on the molecular dynamics simulation analysis of alpha-cobratoxin docked with phytochemical compounds. This can be used as effective drug candidates against the snake and scorpion venom. It should be noted experimental verification is needed to further validate the current data.

Synthetic Peptide Derived from Scorpion Venom Displays Minimal Toxicity and Anti-infective Activity in an Animal Model

Multidrug-resistant bacteria represent a global health problem increasingly leading to infections that are untreatable with our existing antibiotic arsenal. Therefore, it is critical to identify novel effective antimicrobials. Venoms represent an underexplored source of potential antibiotic molecules. Here, we engineered a peptide (IsCT1-NH₂) derived from the venom of the scorpion Opisthacanthus madagascariensis, whose application as an antimicrobial had been traditionally hindered by its high toxicity. Through peptide design and the knowledge obtained in preliminary studies with single and double-substituted analogs, we engineered IsCT1 derivatives with multiple amino acid substitutions to assess the impact of net charge on antimicrobial activity and toxicity. We demonstrate that increased net charge (from +3 to +6) significantly reduced toxicity toward human erythrocytes. Our lead synthetic peptide, [A]¹[K]³[F]⁵[K]⁸-IsCT1-NH₂ (net charge of +4), exhibited increased antimicrobial activity against Gram-negative and Gram-positive bacteria in vitro and enhanced anti-infective activity in a mouse model. Mechanism of action studies revealed that the increased antimicrobial activity of our lead molecule was due, at least in part, to its enhanced ability to permeabilize the outer membrane and depolarize the cytoplasmic membrane. In summary, we describe a simple method based on net charge tuning to turn highly toxic venom-derived peptides into viable therapeutics.

Identification and Characterization of Novel Proteins from Arizona Bark Scorpion Venom That Inhibit Nav1.8, a Voltage-Gated Sodium Channel Regulator of Pain Signaling

The voltage-gated sodium channel Nav1.8 is linked to neuropathic and inflammatory pain, highlighting the potential to serve as a drug target. However, the biophysical mechanisms that regulate Nav1.8 activation and inactivation gating are not completely understood. Progress has been hindered by a lack of biochemical tools for examining Nav1.8 gating mechanisms. Arizona bark scorpion (Centruroides sculpturatus) venom proteins inhibit Nav1.8 and block pain in grasshopper mice (Onychomys torridus). These proteins provide tools for examining Nav1.8 structure–activity relationships. To identify proteins that inhibit Nav1.8 activity, venom samples were fractioned using liquid chromatography (reversed-phase and ion exchange). A recombinant Nav1.8 clone expressed in ND7/23 cells was used to identify subfractions that inhibited Nav1.8 Na⁺ current. Mass-spectrometry-based bottom-up proteomic analyses identified unique peptides from inhibitory subfractions. A search of the peptides against the AZ bark scorpion venom gland transcriptome revealed four novel proteins between 40 and 60% conserved with venom proteins from scorpions in four genera (Centruroides, Parabuthus, Androctonus, and Tityus). Ranging from 63 to 82 amino acids, each primary structure includes eight cysteines and a “CXCE” motif, where X = an aromatic residue (tryptophan, tyrosine, or phenylalanine). Electrophysiology data demonstrated that the inhibitory effects of bioactive subfractions can be removed by hyperpolarizing the channels, suggesting that proteins may function as gating modifiers as opposed to pore blockers.

Scorpion Venom Antimicrobial Peptides Induce Siderophore Biosynthesis and Oxidative Stress Responses in Escherichia coli

The development of life-threatening resistance of pathogenic bacteria to the antibiotics typically in use in hospitals and the community today has led to an urgent need to discover novel antimicrobial agents with different mechanisms of action. As an ancient host defense mechanism of the innate immune system, antimicrobial peptides (AMPs) are attractive candidates to fill that role.

The increasing development of microbial resistance to classical antimicrobial agents has led to the search for novel antimicrobials. Antimicrobial peptides (AMPs) derived from scorpion and snake venoms offer an attractive source for the development of novel therapeutics. Smp24 (24 amino acids [aa]) and Smp43 (43 aa) are broad-spectrum AMPs that have been identified from the venom gland of the Egyptian scorpion Scorpio mauruspalmatus and subsequently characterized. Using a DNA microarray approach, we examined the transcriptomic responses of Escherichia coli to subinhibitory concentrations of Smp24 and Smp43 peptides following 5 h of incubation. Seventy-two genes were downregulated by Smp24, and 79 genes were downregulated by Smp43. Of these genes, 14 genes were downregulated in common and were associated with bacterial respiration. Fifty-two genes were specifically upregulated by Smp24. These genes were predominantly related to cation transport, particularly iron transport. Three diverse genes were independently upregulated by Smp43. Strains with knockouts of differentially regulated genes were screened to assess the effect on susceptibility to Smp peptides. Ten mutants in the knockout library had increased levels of resistance to Smp24. These genes were predominantly associated with cation transport and binding. Two mutants increased resistance to Smp43. There was no cross-resistance in mutants resistant to Smp24 or Smp43. Five mutants showed increased susceptibility to Smp24, and seven mutants showed increased susceptibility to Smp43. Of these mutants, formate dehydrogenase knockout (fdnG) resulted in increased susceptibility to both peptides. While the electrostatic association between pore-forming AMPs and bacterial membranes followed by integration of the peptide into the membrane is the initial starting point, it is clear that there are numerous subsequent additional intracellular mechanisms that contribute to their overall antimicrobial effect.

IMPORTANCE The development of life-threatening resistance of pathogenic bacteria to the antibiotics typically in use in hospitals and the community today has led to an urgent need to discover novel antimicrobial agents with different mechanisms of action. As an ancient host defense mechanism of the innate immune system, antimicrobial peptides (AMPs) are attractive candidates to fill that role. Scorpion venoms have proven to be a rich source of AMPs. Smp24 and Smp43 are new AMPs that have been identified from the venom gland of the Egyptian scorpion Scorpio maurus palmatus, and these peptides can kill a wide range of bacterial pathogens. By better understanding how these AMPs affect bacterial cells, we can modify their structure to make better drugs in the future.

An Smp43-Derived Short-Chain α-Helical Peptide Displays a Unique Sequence and Possesses Antimicrobial Activity against Both Gram-Positive and Gram-Negative Bacteria

Scorpion venoms are rich resources of antimicrobial peptides (AMPs). While the short-chain noncysteine-containing AMPs have attracted much attention as templates for drug development, the antimicrobial potential of long-chain noncysteine-containing AMPs has been largely overlooked. Here, by using the online HeliQuest server, we designed and analyzed a series of 14-residue fragments of Smp43, a 43-residue long-chain noncysteine-containing AMP identified from the venom of Scorpio maurus palmatus. We found that Smp43(1-14) shows high antimicrobial activity against both Gram-positive and Gram-negative bacteria and is nontoxic to mammalian cells at the antimicrobial dosage. Sequence alignments showed that the designed Smp43(1-14) displays a unique primary structure that is different from other natural short-chain noncysteine-containing AMPs from scorpions, such as Uy17, Uy192 and IsCT. Moreover, the peptide Smp43(1-14) caused concentration-dependent fluorescence increases in the bacteria for all of the tested dyes, propidium iodide, SYTOX^TM Green and DiSC₃-5, suggesting that the peptide may kill the bacteria through the formation of pore structures in the plasma membrane. Taken together, our work sheds light on a new avenue for the design of novel short-chain noncysteine-containing AMPs and provides a good peptide template with a unique sequence for the development of novel drugs for use against bacterial infectious diseases.

Venoms as an adjunctive therapy for Parkinson's disease: where are we now and where are we going?

Neurodegenerative diseases, including Parkinson's disease (PD), are increasing in the aging population. Crucially, neurodegeneration of dopaminergic neurons in PD is associated with chronic inflammation and glial activation. Besides this, bradykinesia, resting tremor, rigidity, sensory alteration, and cognitive and psychiatric impairments are also present in PD. Currently, no pharmacologically effective treatment alters the progression of the disease. Discovery and development of new treatment strategies remains a focus for ongoing investigations. For example, one approach is cell therapy to prevent dopaminergic neuronal loss or to slow PD progression. The neuroprotective role of a diverse range of natural products, including venoms from bees, scorpions, snakes and lizards, are also being tested in preclinical PD models and in humans. The main findings from recent studies that have investigated venoms as therapeutic options for PD are summarized in this special report.

Involvement of Toll-like Receptor 4 in Neutrophil-Mediated Inflammation, Oxidative Stress and Tissue Damage Induced by Scorpion Venom

Systemic inflammatory response and generation of oxidative stress are known to contribute to scorpion venom-induced tissue damage. TLR receptors might represent a link between oxidative stress and inflammation; we therefore investigated whether or not TLR4 is involved in venom-induced immunopathology. The obtained results showed that pharmacological targeting of TLR4 with the selective inhibitor TAK-242 (Resatorvid) prevents the inflammatory response induced by subcutaneous administration of Androctonus australis hector (Aah) venom, as revealed by a significant decrease of neutrophil cell count in peripheral blood associated with significant decline of neutrophil degranulation and sequestration to the lung, liver, and kidney tissues. Moreover, TAK-242 administration inhibited nitrite levels increase in serum, malondialdehyde (MDA), and protein carbonyl tissue contents concomitantly with a significant increase of catalase activity and reduced glutathione (GSH) level in tissue homogenates. Furthermore, venom-induced increases in serum levels of organ dysfunction markers (lactate deshydrogenase, aminotransferase ALT and AST, creatinine and urea) were also significantly suppressed by pre-treatment with TLR4 inhibitor, concordantly with a remarkable improvement in the histological features in lung and liver tissues. The results of the present study indicate the potential role of TLR4 in venom-induced immunopathology and show the in vivo requirement of TLR4 signaling in mediating venom-induced tissue damage.

Pioneering Study on Rhopalurus crassicauda Scorpion Venom: Isolation and Characterization of the Major Toxin and Hyaluronidase

Scorpionism is responsible for most accidents involving venomous animals in Brazil, which leads to severe symptoms that can evolve to death. Scorpion venoms consist of complexes cocktails, including peptides, proteins, and non-protein compounds, making separation and purification procedures extremely difficult and time-consuming. Scorpion toxins target different biological systems and can be used in basic science, for clinical, and biotechnological applications. This study is the first to explore the venom content of the unexplored scorpion species Rhopalurus crassicauda, which inhabits exclusively the northernmost state of Brazil, named Roraima, and southern region of Guyana. Here, we pioneer the fractionation of the R. crassicauda venom and isolated and characterized a novel scorpion beta-neurotoxin, designated Rc1, and a monomeric hyaluronidase. R. crassicauda venom and Rc1 (6,882 Da) demonstrated pro-inflammatory activities in vitro and a nociceptive response in vivo. Moreover, Rc1 toxin showed specificity for activating Na_v1.4, Na_v1.6, and BgNa_v1 voltage-gated ion channels. This study also represents a new perspective for the treatment of envenomings in Roraima, since the Brazilian scorpion and arachnid antivenoms were not able to recognize R. crassicauda venom and its fractions (with exception of hyaluronidase). Our work provides useful insights for the first understanding of the painful sting and pro-inflammatory effects associated with R. crassicauda envenomings.

Tuning Scorpion Toxin Selectivity: Switching From KV1.1 to KV1.3

Voltage-gated potassium channels (K_Vs) perform vital physiological functions and are targets in different disorders ranging from ataxia and arrhythmia to autoimmune diseases. An important issue is the search for and production of selective ligands of these channels. Peptide toxins found in scorpion venom named KTx excel in both potency and selectivity with respect to some potassium channel isoforms, which may present only minute differences in their structure. Despite several decades of research the molecular determinants of KTx selectivity are still poorly understood. Here we analyze MeKTx13-3 (Kalium ID: α-KTx 3.19) from the lesser Asian scorpion Mesobuthus eupeus, a high-affinity K_V1.1 blocker (IC₅₀ ~2 nM); it also affects K_V1.2 (IC₅₀ ~100 nM), 1.3 (~10 nM) and 1.6 (~60 nM). By constructing computer models of its complex with K_V1.1-1.3 channels we identify specific contacts between the toxin and the three isoforms. We then perform mutagenesis to disturb the identified contacts with K_V1.1 and 1.2 and produce recombinant MeKTx13-3_AAAR, which differs by four amino acid residues from the parent toxin. As predicted by the modeling, this derivative shows decreased activity on K_V1.1 (IC₅₀ ~550 nM) and 1.2 (~200 nM). It also has diminished activity on K_V1.6 (~1500 nM) but preserves K_V1.3 affinity as measured using the voltage-clamp technique on mammalian channels expressed in Xenopus oocytes. In effect, we convert a selective K_V1.1 ligand into a new specific K_V1.3 ligand. MeKTx13-3 and its derivatives are attractive tools to study the structure-function relationship in potassium channel blockers.

Voltage-Gated K+/Na+ Channels and Scorpion Venom Toxins in Cancer

Ion channels have recently been recognized as novel therapeutic targets in cancer research since they are overexpressed in different histological tissues, and their activity is linked to proliferation, tumor progression, angiogenesis, metastasis, and apoptosis. Voltage gated-potassium channels (VGKC) are involved in cell proliferation, cancer progression, cell cycle transition, and apoptosis. Moreover, voltage-dependent sodium channels (VGSC) contribute to decreases in extracellular pH, which, in turn, promotes cancer cell migration and invasion. Furthermore, VGSC and VGKC modulate voltage-sensitive Ca²⁺ channel activity by controlling the membrane potential and regulating Ca²⁺ influx, which functions as a second messenger in processes related to proliferation, invasion, migration, and metastasis. The subgroup of these types of channels that have shown a high oncogenic potential have become known as “oncochannels”, and the evidence has highlighted them as key potential therapeutic targets. Scorpion venoms contain a high proportion of peptide toxins that act by modulating voltage-gated Na⁺/K⁺ channel activity. Increasing scientific data have pointed out that scorpion venoms and their toxins can affect the activity of oncochannels, thus showing their potential for anticancer therapy. In this review, we provide an update of the most relevant voltage-gated Na⁺\K⁺ ion channels as cellular targets and discuss the possibility of using scorpion venom and toxins for anticancer therapy.

Scorpion Venom: Detriments and Benefits

Scorpion venom may cause severe medical complications and untimely death if injected into the human body. Neurotoxins are the main components of scorpion venom that are known to be responsible for the pathological manifestations of envenoming. Besides neurotoxins, a wide range of other bioactive molecules can be found in scorpion venoms. Advances in separation, characterization, and biotechnological approaches have enabled not only the development of more effective treatments against scorpion envenomings, but have also led to the discovery of several scorpion venom peptides with interesting therapeutic properties. Thus, scorpion venom may not only be a medical threat to human health, but could prove to be a valuable source of bioactive molecules that may serve as leads for the development of new therapies against current and emerging diseases. This review presents both the detrimental and beneficial properties of scorpion venom toxins and discusses the newest advances within the development of novel therapies against scorpion envenoming and the therapeutic perspectives for scorpion toxins in drug discovery.

Scorpion venoms and associated toxins as anticancer agents: update on their application and mechanism of action

Cancer remains one of the deadliest non-infectious diseases of the 21^st century, causing millions of mortalities per year worldwide. Analyses of conventional treatments, such as radiotherapy and chemotherapy, have shown not only a lower therapeutic efficiency rate but also plethora of side-effects. Considering the desperate need to identify promising anticancer agents, researchers are in quest to design and develop new tumoricidal drugs from natural sources. Over the past few years, scorpion venoms have shown exemplary roles as pivotal anticancer agents. Scorpion venoms associated metabolites, particularly toxins demonstrated in vitro anticancer attributes against diversified cell lines by inhibiting the growth and progression of the cell cycle, inhibiting metastasis by blocking ion channels such as K⁺ and Cl^- , and/or inducing apoptosis by intrinsic and extrinsic pathways. This review sheds light not only on in vitro anticancer properties of distinct scorpion venoms and their toxins, but also on their mechanism of action for designing and developing new therapeutic drugs in future.

Interleukin-1 Receptor-Induced Nitric Oxide Production in the Pancreas Controls Hyperglycemia Caused by Scorpion Envenomation

Tityus serrulatus causes numerous scorpion envenomation accidents and deaths worldwide. The symptoms vary from local to systemic manifestations, culminating in pulmonary edema and cardiogenic shock. Among these events, transitory hyperglycemia is a severe manifestation that influences pulmonary edema, hemodynamic alterations, and cardiac disturbances. However, the molecular mechanism that leads to increased glucose levels after T. serrulatus envenomation remains unknown. This study aimed to investigate our hypothesis that hyperglycemia due to scorpion envenomation involves inflammatory signaling in the pancreas. The present study showed that T. serrulatus venom induces the production of IL-1α and IL-1β in the pancreas, which signal via IL-1R and provoke nitric oxide (NO) production as well as edema in β-cells in islets. Il1r1^−/− mice were protected from transitory hyperglycemia and did not present disturbances in insulin levels in the serum. These results suggest that the pathway driven by IL-1α/IL-1β-IL-1R-NO inhibits insulin release by β-cells, which increases systemic glucose concentration during severe scorpion envenomation. A supportive therapy that inhibits NO production, combined with antiserum, may help to prevent fatal outcomes of scorpion envenomation. Our findings provide novel insights into the design of supportive therapy with NO inhibitors combined with antiscorpion venom serum to overcome fatal outcomes of scorpion envenomation.

Preparation and Biological Evaluation of ⁶⁷Gallium- Labeled Iranian Hemiscorpius Lepturus Scorpion Venom

Background

The Hemiscorpius lepturus (H. lepturus) is a deadly scorpion species living in the southern Iran.

Objective

H. lepturus induces delayed toxicity symptoms and understanding the long term biodistribution/biokinetic of the venom is of great interest in toxicology.

Methods

A Ga-67 labeled venom was prepared using a DOTA -conjugated venom followed by radiolabeling using ⁶⁷GaCl₃ at 40°C for 90 min. The purification of the radiolabeled venom was performed using size exclusion-chromatography (radiochemical purity 71%). The radiolabeled venom was stable in the final solution in the presence of human serum at 37°C for 72 hours. The tissue distribution was studied in blood, heart, liver, spleen, muscle, brain, kidney, intestine and skin tissues at the intervals of 1, 4, 24, 48 and 72 hours using tissue counting and SPECT imaging.

Results

The radiolabeled venom mixture obtained with an estimated molar activity of 0.52 MBq/µg. The main accumulation tissues during the first 72 hours were kidneys, blood, liver, intestines, stomach and skin, respectively. Therefore, it is likely that H. lepturus’ clinical effects and renal toxicity are primary and caused by direct effects of the H. lepturus venom.

Conclusion

The results have largely shown the direct clinical effects on the studied tissues during the 72-hour period and antivenom administration can strongly alleviate the toxicity effects as early as 72 hours in the management of the patients.

1,4-Benzoquinone antimicrobial agents against Staphylococcus aureus and Mycobacterium tuberculosis derived from scorpion venom

Two 1,4-benzoquinone derivatives, found in the venom of the scorpion Diplocentrus melici following exposure to air, have been isolated, characterized, synthesized, and assessed for antimicrobial activities. Initially a white, viscous liquid, the extracted venom colors within minutes under ambient conditions. From this colored mixture, two compounds, one red, the other blue, were isolated and purified using chromatography. After a variety of NMR and mass spectrometry experiments, the red compound was determined to be 3,5- dimethoxy-2-(methylthio)cyclohexa-2,5-diene-1,4-dione, and the blue compound was determined to be 5-methoxy-2,3- bis(methylthio)cyclohexa-2,5-diene-1,4-dione. Because extremely small amounts of these compounds were isolated from the scorpion venom, we developed laboratory syntheses from commercially available precursors, allowing us to produce sufficient quantities for crystallization and biological assays. The red benzoquinone is effective against Staphylococcus aureus [minimum inhibitory concentration (MIC) = 4 µg/mL], while the blue benzoquinone is active against Mycobacterium tuberculosis (MIC = 4 µg/mL) and even against a multidrug-resistant (MDR) strain with nearly equal effectiveness. The bactericidal effects of both benzoquinones show comparable activity to commercially available antibiotics used against these pathogens and were cytotoxic to neoplastic cell lines, suggesting their potential as lead compounds for the development of novel antimicrobial and anticancer drugs. Importantly, the blue benzoquinone was also effective in vivo with mouse models of MDR tuberculosis infection. After treatment for 2 mo, four mice with late-stage active MDR tuberculosis had a significant decrease in pulmonary bacillary loads and tissue damage. Healthy mice served as negative controls and tolerated treatment well, without adverse side effects.

Isolation and Characterization of Insecticidal Toxins from the Venom of the North African Scorpion, Buthacus leptochelys

Various bioactive peptides have been identified in scorpion venom, but there are many scorpion species whose venom has not been investigated. In this study, we characterized venom components of the North African scorpion, Buthacus leptochelys, by mass spectrometric analysis and evaluated their insect toxicity. This is the first report of chemical and biological characterization of the B. leptochelys venom. LC/MS analysis detected at least 148 components in the venom. We isolated four peptides that show insect toxicity (Bl-1, Bl-2, Bl-3, and Bl-4) through bioassay-guided HPLC fractionation. These toxins were found to be similar to scorpion α- and β-toxins based on their N-terminal sequences. Among them, the complete primary structure of Bl-1 was determined by combination of Edman degradation and MS/MS analysis. Bl-1 is composed of 67 amino acid residues and crosslinked with four disulfide bonds. Since Bl-1 shares high sequence similarity with α-like toxins, it is likely that it acts on Na⁺ channels of both insects and mammals.

Proteome of fraction from Tityus serrulatus venom reveals new enzymes and toxins

Background

Tityus serrulatus venom (Ts venom) is a complex mixture of several compounds with biotechnological and therapeutical potentials, which highlights the importance of the identification and characterization of these components. Although a considerable number of studies have been dedicated to the characterization of this complex cocktail, there is still a limitation of knowledge concerning its venom composition. Most of Ts venom studies aim to isolate and characterize their neurotoxins, which are small, basic proteins and are eluted with high buffer concentrations on cation exchange chromatography. The first and largest fraction from carboxymethyl cellulose-52 (CMC-52) chromatography of Ts venom, named fraction I (Fr I), is a mixture of proteins of high and low molecular masses, which do not interact with the cation exchange resin, being therefore a probable source of components still unknown of this venom. Thus, the present study aimed to perform the proteome study of Fraction I from Ts venom, by high resolution mass spectrometry, and its biochemical characterization, by the determination of several enzymatic activities.

Methods

Fraction I was obtained by a cation exchange chromatography using 50 mg of crude venom. This fraction was subjected to a biochemical characterization, including determination of L-amino acid oxidase, phospholipase, hyaluronidase, proteases activities and inhibition of angiotensin converting enzyme (ACE) activity. Fraction I was submitted to reduction, alkylation and digestion processes, and the tryptic digested peptides obtained were analyzed in a Q-Exactive Orbitrap mass spectrometer. Data analysis was performed by PEAKS 8.5 software against NCBI database.

Results

Fraction I exhibits proteolytic activity and it was able to inhibit ACE activity. Its proteome analysis identified 8 different classes of venom components, among them: neurotoxins (48%), metalloproteinases (21%), hypotensive peptides (11%), cysteine-rich venom protein (9%), antimicrobial peptides (AMP), phospholipases and other enzymes (chymotrypsin and lysozymes) (3%) and phosphodiesterases (2%).

Conclusions

The combination of a proteomic and biochemical characterization strategies leads us to identify new components in the T. serrulatus scorpion venom. The proteome of venom´s fraction can provide valuable direction in the obtainment of components in their native forms in order to perform a preliminary characterization and, consequently, to promote advances in biological discoveries in toxinology.

Potent and Broad-Spectrum Antimicrobial Activity of Analogs from the Scorpion Peptide Stigmurin

Scorpion venom constitutes a rich source of biologically active compounds with high potential for therapeutic and biotechnological applications that can be used as prototypes for the design of new drugs. The aim of this study was to characterize the structural conformation, evaluate the antimicrobial activity, and gain insight into the possible action mechanism underlying it, for two new analog peptides of the scorpion peptide Stigmurin, named StigA25 and StigA31. The amino acid substitutions in the native sequence for lysine residues resulted in peptides with higher positive net charge and hydrophobicity, with an increase in the theoretical helical content. StigA25 and StigA31 showed the capacity to modify their structural conformation according to the environment, and were stable to pH and temperature variation—results similar to the native peptide. Both analog peptides demonstrated broad-spectrum antimicrobial activity in vitro, showing an effect superior to that of the native peptide, being non-hemolytic at the biologically active concentrations. Therefore, this study demonstrates the therapeutic potential of the analog peptides from Stigmurin and the promising approach of rational drug design based on scorpion venom peptide to obtain new anti-infective agents.

Lysine to arginine mutagenesis of chlorotoxin enhances its cellular uptake

Chlorotoxin (CTX), a disulfide-rich peptide from the scorpion Leiurus quinquestriatus, has several promising biopharmaceutical properties, including preferential affinity for certain cancer cells, high serum stability, and cell penetration. These properties underpin its potential for use as a drug design scaffold, especially for the treatment of cancer; indeed, several analogs of CTX have reached clinical trials. Here, we focus on its ability to internalize into cells-a trait associated with a privileged subclass of peptides called cell-penetrating peptides-and whether it can be improved through conservative substitutions. Mutants of CTX were made using solid-phase peptide synthesis and internalization into human cervical carcinoma (HeLa) cells was monitored by fluorescence and confocal microscopy. CTX_M1 (ie, [K15R/K23R]CTX) and CTX_M2 (ie, [K15R/K23R/Y29W]CTX) mutants showed at least a twofold improvement in uptake compared to CTX. We further showed that these mutants internalize into HeLa cells largely via an energy-dependent mechanism. Importantly, the mutants have high stability, remaining intact in serum for over 24 h; thus, retaining the characteristic stability of their parent peptide. Overall, we have shown that simple conservative substitutions can enhance the cellular uptake of CTX, suggesting that such type of mutations might be useful for improving uptake of other peptide toxins.

Potential Applications of Venom Peptides as Anti-Thrombotic Agents for Management of Arterial and Deep-Vein Thrombosis

BACKGROUND

Thrombus is composed of two main substances i.e. red blood cells and aggregated platelets which make a web of inter-connected fibrin proteins. During injury it prevents bleeding, so it is very useful but it can be very dangerous if it is produced in healthy blood vessels and block the blood flow through it. Mural thrombi attaches with the blood vessels but in most cases do not block it completely. Venoms are an incredible source of peptides having amazing bioactivities with varying number of amino acid residues. Anticoagulant venom peptides however inhibit the enzyme taking part in coagulation like factor Xa and thrombin. The anticoagulant potential of venom peptides have also been reported by the degradation of the fibrin or fibrinogen related to serine or metalloproteases. Designing and development of numerous therapeutic agents or lead molecules mostly for cardiovascular diseases have been motivated from toxins/proteins from snake venoms. For example, disintegrins, a large family of platelet aggregation inhibitors found in viperid and crotalid snake venoms were the basis for designing of platelet aggregation inhibitors such as eptifibatide and tirofiban.

CONCLUSION

Ancrod isolated from Malayan pit viper venom can cause reduction in level of blood fibrinogen and has been effectively tried in various ischemic conditions, including stroke. In order to search for novel lead molecules, the emphasis should be on isolation and characterization of pharmacologically active snake venoms proteins affecting blood coagulation and platelet aggregation. In this review an attempt has been made to recapitulates and discuss venoms of different animals and arthropod having anticoagulant peptides for their potential use in therapeutics and diagnostics.

Tb II-I, a Fraction Isolated from Tityus bahiensis Scorpion Venom, Alters Cytokines': Level and Induces Seizures When Intrahippocampally Injected in Rats

Scorpion venoms are composed of several substances with different pharmacological activities. Neurotoxins exert their effects by targeting ion channels resulting in toxic effects to mammals, insects and crustaceans. Tb II-I, a fraction isolated from Tityus bahiensis scorpion venom, was investigated for its ability to induce neurological and immune-inflammatory effects. Two putative &beta;-sodium channel toxins were identified in this fraction, Tb2 II and Tb 4, the latter having been completely sequenced by mass spectrometry. Male Wistar rats, stereotaxically implanted with intrahippocampal cannulas and electrodes, were injected with Tb II-I (2 &micro;g/2 &micro;L) via the intrahippocampal route. The behavior, electrographic activity and cellular integrity of the animals were analyzed and the intracerebral level of cytokines determined. Tb II-I injection induced seizures and damage in the hippocampus. These alterations were correlated with the changes in the level of the cytokines tumoral necrosis factor-&alpha; (TNF-&alpha;) and interleukin-6 (IL-6). Therefore, the binding of Tb II-I to its target in the central nervous system may induce inflammation resulting in neuropathological and behavioral alterations.

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.

Effects of Medium Molecular Weight Heparinyl Arginine on Scorpion Venom-induced Pulmonary Edema in Rats

BACKGROUND/AIM

The aim of this study was to examine the inhibitory action of medium molecular weight heparinyl amino acid derivatives (MHADs) on scorpion venom (SV)-induced acute pulmonary edema.

MATERIALS AND METHODS

SV was injected into the tail vein of rats after MHAD pre-treatment. An hour later, lungs were removed from each experimental animal, followed by measurement of the lung/body index (LBI) and Na⁺/K⁺ ratio of the pulmonary tissue as indices for acute pulmonary edema.

RESULTS

Medium molecular weight heparinyl arginine (MHR)-administered rats exhibited significantly lower LBI and Na⁺/K⁺ ratios compared to control rats. Although the mechanism of inhibitory action of MHR on pulmonary edema is unclear, MHR inhibited the vascular permeability increase by SV because both LBI and Na⁺/K⁺ ratio of the pulmonary tissue remained at almost normal values.

CONCLUSION

MHR may prevent scorpion venom-induced acute pulmonary edema and thus makes a good candidate for clinical use.

Effects of Medium Molecular Weight Heparinyl Arginine on Scorpion Venom-induced Pulmonary Edema in Rats

BACKGROUND/AIM

The aim of this study was to examine the inhibitory action of medium molecular weight heparinyl amino acid derivatives (MHADs) on scorpion venom (SV)-induced acute pulmonary edema.

MATERIALS AND METHODS

SV was injected into the tail vein of rats after MHAD pre-treatment. An hour later, lungs were removed from each experimental animal, followed by measurement of the lung/body index (LBI) and Na+/K+ ratio of the pulmonary tissue as indices for acute pulmonary edema.

RESULTS

Medium molecular weight heparinyl arginine (MHR)-administered rats exhibited significantly lower LBI and Na+/K+ ratios compared to control rats. Although the mechanism of inhibitory action of MHR on pulmonary edema is unclear, MHR inhibited the vascular permeability increase by SV because both LBI and Na+/K+ ratio of the pulmonary tissue remained at almost normal values.

CONCLUSION

MHR may prevent scorpion venom-induced acute pulmonary edema and thus makes a good candidate for clinical use.

Analogs of the Scorpion Venom Peptide Stigmurin: Structural Assessment, Toxicity, and Increased Antimicrobial Activity

Scorpion venom is a rich source of biologically active components and various peptides with high-potential therapeutic use that have been characterized for their antimicrobial and antiproliferative activities. Stigmurin is a peptide identified from the Tityus stigmurus venom gland with high antibacterial and antiproliferative activities and low toxicity. Amino acid substitutions in peptides without a disulfide bridge sequence have been made with the aim of reducing their toxicity and increasing their biological activities. The purpose of this study was to evaluate the structural conformation and structural stability, as well as antimicrobial, antiproliferative, and hemolytic activities of two peptide analogs to Stigmurin, denominated StigA6 and StigA16. In silico analysis revealed the α-helix structure for both analog peptides, which was confirmed by circular dichroism. Data showed that the net charge and hydrophobic moment of the analog peptides were higher than those for Stigmurin, which can explain the increase in antimicrobial activity presented by them. Both analog peptides exhibited activity on cancerous cells similar to the native peptide; however, they were less toxic when tested on the normal cell line. These results reveal a potential biotechnological application of the analog peptides StigA6 and StigA16 as prototypes to new therapeutic agents.

Spermaurin, an La1-like peptide from the venom of the scorpion Scorpio maurus palmatus, improves sperm motility and fertilization in different mammalian species

STUDY QUESTION

Is it possible to identify original compounds that are able to enhance sperm motility from the venom of the scorpion Scorpio maurus palmatus?

SUMMARY ANSWER

We identified a potent disulfide-rich peptide (DRP) of 73 amino acids that significantly improved the motility of fresh and frozen-thawed sperm in different mammalian species, including human, and improved fertilization outcome in mouse IVF experiments.

WHAT IS KNOWN ALREADY

Any disturbance of sperm motility has a strong impact on fertilization and can lead to subfertility or infertility. Significant efforts have, therefore,  been made to identify pharmacological drugs that might improve sperm motility. Such compounds are particularly useful in azoospermia to improve testicular sperm extraction and in the domain of cryopreservation because the motility of frozen-thawed sperm is reduced.

STUDY DESIGN, SIZE, DURATION

This was a basic science/medical research study aimed at identifying original compounds from a library of venoms able to enhance mammalian sperm motility, including human. We first identified in the venom of a scorpion S. m. palmatus a fraction able to potently activate sperm motility. We next purified and characterized the compound by liquid chromatography, mass spectrometry and peptide synthesis. Finally, the potency and toxicity of both purified and synthetic versions of the identified compound on sperm motility were assessed using different in vitro tests in different mammalian species.

PARTICIPANTS/MATERIALS, SETTING, METHODS

For human sperm, biological samples were collected from normozoospermic donors and subfertile patients attending a reproduction department for diagnostic semen analysis. Testicular sperm was collected from cynomolgus monkeys (Macaca fascicularis) euthanized for the needs of specific authorized research projects. The peptide was also tested on bovine and mouse epidydimal sperm. We measured different sperm motility parameters with a computer-assisted sperm analysis system in the presence or absence of the peptide.

MAIN RESULTS AND THE ROLE OF CHANCE

Size exclusion chromatography enabled us to isolate a fraction of the venom of S. m. palmatus able to increase sperm motility. By liquid chromatography and mass spectrometry, a peptide comprising 73 amino acids with 4 disulfide bridges was identified as responsible for the biological activity and called 'spermaurin'. The identity of spermaurin was confirmed by chemical synthesis. We showed that the peptide increased the motility of fresh and frozen-thawed human sperm. We observed that the potency of the peptide was higher on fresh ejaculated spermatozoa with a low motility, achieving a 100% increase of curvilinear velocity in poorly performing sperm. We also demonstrated that peptide is effective on bovine and mouse fresh epididymal, bovine frozen-thawed ejaculated and fresh non-human primate testicular sperm. Finally, in mouse IVF, the production of 2-cell embryos was increased by 24% when sperm were treated with the peptide.

LIMITATIONS, REASONS FOR CAUTION

This work is an in vitro evaluation of the ability of spermaurin to improve sperm motility parameters. Another limitation of this study is the small number of human sperm samples tested with the natural (n = 36) and synthetic (n = 12) peptides. Moreover, the effect of the peptide on IVF outcome was only tested in mouse and further tests with human and bovine gametes are required to confirm and extend this result in other mammalian species.

WIDER IMPLICATIONS OF THE FINDINGS

This work confirms our initial study showing that venoms represent an interesting source of molecules that are able to modify sperm physiology. Moreover, this work presents the first demonstrated biological action of a venom peptide from the scorpion S. m. palmatus with sequence similarities to La1 peptide from Liocheles australasiae (Wood scorpion), a widespread family of DRPs.

LARGE SCALE DATA

Not applicable.

STUDY FUNDING/COMPETING INTEREST(S)

This work is part of the project 'LAB COM-14 LAB7 0004 01-LIPAV', funded by the program LabCom 2014 from the French Research Agency (ANR). Dr Arnoult reports grants from IMV Technologies during the conduct of the study. In addition, Drs Arnoult, Martinez, Ray and Schmitt have a patent EP16305642.7 pending containing some of the information presented in this manuscript.

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.

[Research progress on medicinal values of scorpion venom components]

For thousands of years, scorpions and their venoms have been applied in traditional medicine in China to treat a variety of difficult miscellaneous diseases. The venom is a complex mixture of bioactive molecules, such as peptides and proteins (e.g. neurotoxins). Among them, neurotoxins (named scorpion toxins) are the most important bioactive components. Up to now, more and more characterized venom components have been isolated from different scorpions, providing numerous candidate molecules for drug design and development. Many investigations have shown the potent effects of venom or its components against the nervous, immune, infection, cardiovascular and neoplastic diseases. Moreover, the scorpion toxins could be used as molecular backbone to develop new specific drugs based on their unique structures and functions. In this review, we focus on the medicinal values and the possible mechanisms of scorpion toxins with promising medicinal prospect against the relative diseases, providing the data basis for further development of relative drugs.

Aspidosperma pyrifolium Has Anti-Inflammatory Properties: An Experimental Study in Mice with Peritonitis Induced by Tityus serrulatus Venom or Carrageenan

Scorpions of the genus Tityus are responsible for the majority of envenomation in Brazil, the Tityus serrulatus species being the most common and dangerous in South America. In this approach, we have investigated the ability of the aqueous extract from the leaves of Aspidosperma pyrifolium in reducing carrageenan-induced inflammation and the inflammation induced by T. serrulatus envenomation in mice. We also evaluated the cytotoxic effects of this extract, using the 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl-2H-tetrazolium (MTT) assay and the results revealed that the extract is safe. Analysis by High Performance Liquid Chromatography coupled with Diode Array Detector (HPLC-DAD) and Liquid Chromatography Coupled with Mass Spectrometry with Diode Array Detection (LC-DAD-MS) showed one major chemical component, the flavonoid rutin and phenolics compounds. For in vivo studies in carrageenan-induced peritonitis model, mice received extracts, dexamethasone, rutin or saline, before administration of carrageenan. For venom-induced inflammation model, animals received T. serrulatus venom and were, simultaneously, treated with extracts, antivenom, rutin or saline. The extract and rutin showed a reduction in the cell migration into the peritoneal cavity, and in the same way the envenomated animals also showed reduction of edema, inflammatory cell infiltration and vasodilation in lungs. This is an original study revealing the potential action of A. pyrifolium against inflammation caused by Tityus serrulatus venom and carrageenan, revealing that this extract and its bioactive molecules, specifically rutin, may present potential anti-inflammatory application.

Scorpion and spider venoms in cancer treatment: state of the art, challenges, and perspectives

Background and Aim: Animal venoms comprise a mix of bioactive molecules with high affinity for multiple targets in cells and tissues. Scorpion and spider venoms and purified peptides exhibit significant effects on cancer cells, encompassing four potential mechanisms: 1) induction of cell cycle arrest, growth inhibition, and apoptosis; 2) inhibition of angiogenesis; 3) inhibition of invasion and metastasis; and 4) blocking of specific transmembrane channels. Tumor biology is complex and entails many intertwined processes, as reflected in the putative hallmarks of cancer. This complexity, however, gives rise to numerous (potential) pharmacological intervention sites. Molecules that target multiple proteins or pathways, such as components of animal venoms, may therefore be effective anti-cancer agents. The objective of this review was to address the anti-cancer properties and in vitro mechanisms of scorpion and spider venoms and toxins, and highlight current obstacles in translating the preclinical research to a clinical setting. Relevance for patients: Cancer is a considerable global contributor to disease-related death. Despite some advances being made, therapy remains palliative rather than curative for the majority of cancer indications. Consequently, more effective therapies need to be devised for poorly responding cancer types to optimize clinical cancer management. Scorpion and spider venoms may occupy a role in the development of improved anti-cancer modalities.

Rhopalurus junceus scorpion venom induces apoptosis in the triple negative human breast cancer cell line MDA-MB-231

Rhopalurus junceus scorpion venom has demonstrated high cytotoxic activity in epithelial cancer cells. In the present study, the effect of scorpion venom on cell viability and apoptosis was evaluated in the MDA-MB-231 human breast carcinoma cell line. Cell viability was analyzed using MTT assay. The cell death event was examined trough end-point RT-PCR to identify the expression of apoptosis-related genes, fluorescent microscopy and mitochondrial membrane potential (ΔΨm) alteration. The results demonstrated that scorpion venom induced apoptosis in MDA-MB-231 cells in a time-dependent manner. Besides, scorpion venom treatment also resulted in p53, bax, noxa, puma, caspase 3 and p21 over-expression, while the expression of bcl-2 and bcl-xl was down-regulated. Apoptosis was associated with depolarization of ΔΨm. The overall effect indicates that the selective cytotoxic effect of the scorpion venom is associated with its apoptosis-inducing effect through the mitochondrial pathway. Therefore, R. junceus scorpion venom may be an interesting natural extract for further investigation in breast cancer treatment strategies.

Non-disulfide-Bridge Peptide 5.5 from the Scorpion Hadrurus gertschi Inhibits the Growth of Mycobacterium abscessus subsp. massiliense

Multi-drug resistant microorganisms have been a growing concern during the last decades due to their contribution in mortality rates worldwide. Antimicrobial peptides (AMPs) are broad spectrum antimicrobial agents that display potent microbicidal activity against a wide range of microorganisms. AMPs generally have a rapid mode of action that reduces the risk of resistance developing among pathogens. In this study, an AMP derived from scorpion venom, NDBP-5.5, was evaluated against Mycobacterium abscessus subsp. massiliense, a rapidly growing and emerging pathogen associated with healthcare infections. The minimal bactericidal concentration of NDBP-5.5, AMP quantity necessary to stop bacteria visible growth, against M. abscessus subsp. massiliense was 200 μM, a concentration that did not induce hemolysis of human red blood cells. The therapeutic index was 3.05 indicating a drug with low toxicity and therefore good clinical potential. Treatment of infected macrophages with NDBP-5.5 or clarithromycin presented similar results, reducing the bacterial load. M. abscessus subsp. massiliense-infected animals showed a decrease in the bacterial load of up to 70% when treated with NDBP-5.5. These results revealed the effective microbicidal activity of NDBP-5.5 against Mycobacterium, indicating its potential as an antimycobacterial agent.

In vitro determination of the efficacy of scorpion venoms as anti-cancer agents against colorectal cancer cells: a nano-liposomal delivery approach

The use of liposomes in biological and medicinal sciences is a relatively new approach. The liposomal strategy greatly depends on the technological advancement in the formation of vesicles of various sizes and properties. In the current study, we encapsulated the venoms obtained from medically important scorpions such as Androctonus bicolor (AB), Androctonus crassicauda (AC), and Leiurus quinquestriatus (LQ). To begin with, our first and foremost aim was to prepare biocompatible and biodegradable nanovesicles. Additionally, we intended to enhance the anti-cancer potential of these encapsulated venoms. The liposomal venoms were prepared by rehydration and dehydration methods. Morphology, particle size, and size distribution of the liposomes were examined by scanning electron microscope (SEM), transmission electron microscope (TEM), and Zetasizer. We found that the prepared liposomes had a smooth surface and a spherical/ovoid shape and existed mainly as single unilamellar vesicles (SUVs). Furthermore, the liposomal formulation of all three venoms exhibited excellent stability and good encapsulation efficiency (EE). Additionally, the anti-cancer potential of the encapsulated venoms was also evaluated on a colorectal cancer cell line (HCT-8). The venom-loaded liposomes showed elevated anti-cancer properties such as low rate of cell survival, higher reactive oxygen species (ROS) generation, and enhancement in the number of apoptotic cells. In addition to this, cell cycle analysis revealed G0/G1 enrichment upon venom treatment. The effect of treatment was more pronounced when venom-liposome was used as compared to free venom on the HCT-8 cell line. Furthermore, we did not observe any interference of liposomal lipids used in these preparations on the progression of cancer cells. Considering these findings, we can conclude that the encapsulated scorpion venoms exhibit better efficacy and act more vigorously as an anti-cancer agent on the colorectal cancer cell line when compared with their free counterpart.

Exon Shuffling and Origin of Scorpion Venom Biodiversity

Scorpion venom is a complex combinatorial library of peptides and proteins with multiple biological functions. A combination of transcriptomic and proteomic techniques has revealed its enormous molecular diversity, as identified by the presence of a large number of ion channel-targeted neurotoxins with different folds, membrane-active antimicrobial peptides, proteases, and protease inhibitors. Although the biodiversity of scorpion venom has long been known, how it arises remains unsolved. In this work, we analyzed the exon-intron structures of an array of scorpion venom protein-encoding genes and unexpectedly found that nearly all of these genes possess a phase-1 intron (one intron located between the first and second nucleotides of a codon) near the cleavage site of a signal sequence despite their mature peptides remarkably differ. This observation matches a theory of exon shuffling in the origin of new genes and suggests that recruitment of different folds into scorpion venom might be achieved via shuffling between body protein-coding genes and ancestral venom gland-specific genes that presumably contributed tissue-specific regulatory elements and secretory signal sequences.

B1-kinin receptors modulate Mesobuthus tamulus venom-induced vasosensory reflex responses in anesthetized rats

OBJECTIVE

Intra-arterial injection of Mesobuthus tamulus (BT) venom produces reflex vasosensory responses modulating cardiorespiratory parameters in albino rats. The present study was conducted to understand the role of kinin receptors in modulating vasosensory reflexes evoked by BT venom.

MATERIALS AND METHODS

In urethane-anesthetized rats, tracheostomy was performed to keep the airway patent. The femoral artery was cannulated proximally, as well as distally, to record the blood pressure (BP) and to inject the chemicals, respectively. Electrocardiographic and respiratory excursions were recorded to compute the heart rate (HR) and respiratory rate (RR). A group of animals was pretreated with saline/kinin receptor antagonists intra-arterially (B1/B2 receptor antagonists) before the injection of venom.

RESULTS

After intra-arterial injection of BT venom (1 mg/kg), there was an immediate increase in RR, which reached to 40% within 30 s, followed by a decrease of 40%. Further, there was sustained increase in RR (50%) up to 60 min. The BP started to increase at 40 s, peaking at 5 min (50%), and remained above the initial level up to 60 min. The bradycardiac response started after 5 min which peaked (50% of initial) at 25 min and remained at that level up to 60 min. In B1 receptor antagonist (des-Arg) pretreated animals, venom-induced cardiovascular responses were attenuated (by 20-25% in mean arterial pressure and HR) significantly but not in B2 receptor antagonist (Hoe-140) pretreated animals. Either of the antagonists failed to alter the RR responses.

CONCLUSIONS

BT venom-induced vasosensory reflex responses modulating cardiovascular parameters are mediated via B1-kinin receptors in anesthetized rats.

Biotechnological Trends in Spider and Scorpion Antivenom Development

Spiders and scorpions are notorious for their fearful dispositions and their ability to inject venom into prey and predators, causing symptoms such as necrosis, paralysis, and excruciating pain. Information on venom composition and the toxins present in these species is growing due to an interest in using bioactive toxins from spiders and scorpions for drug discovery purposes and for solving crystal structures of membrane-embedded receptors. Additionally, the identification and isolation of a myriad of spider and scorpion toxins has allowed research within next generation antivenoms to progress at an increasingly faster pace. In this review, the current knowledge of spider and scorpion venoms is presented, followed by a discussion of all published biotechnological efforts within development of spider and scorpion antitoxins based on small molecules, antibodies and fragments thereof, and next generation immunization strategies. The increasing number of discovery and development efforts within this field may point towards an upcoming transition from serum-based antivenoms towards therapeutic solutions based on modern biotechnology.

Structure-Activity Relationship of Chlorotoxin-Like Peptides

Animal venom (e.g., scorpion) is a rich source of various protein and peptide toxins with diverse physio-/pharmaco-logical activities, which generally exert their action via target-specific modulation of different ion channel functions. Scorpion venoms are among the most widely-known source of peptidyl neurotoxins used for callipering different ion channels, such as; Na⁺, K⁺, Ca⁺, Cl(-), etc. A new peptide of the chlorotoxin family (i.e., Bs-Tx7) has been isolated, sequenced and synthesized from scorpion Buthus sindicus (family Buthidae) venom. This peptide demonstrates 66% with chlorotoxin (ClTx) and 82% with CFTR channel inhibitor (GaTx1) sequence identities reported from Leiurus quinquestriatus hebraeus venom. The toxin has a molecular mass of 3821 Da and possesses four intra-chain disulphide bonds. Amino acid sequence analysis of Bs-Tx7 revealed the presence of a scissile peptide bond (i.e., Gly-Ile) for human MMP2, whose activity is increased in the case of tumour malignancy. The effect of hMMP2 on Bs-Tx7, or vice versa, observed using the FRET peptide substrate with methoxycoumarin (Mca)/dinitrophenyl (Dnp) as fluorophore/quencher, designed and synthesized to obtain the lowest Km value for this substrate, showed approximately a 60% increase in the activity of hMMP2 upon incubation of Bs-Tx7 with the enzyme at a micromolar concentration (4 µM), indicating the importance of this toxin in diseases associated with decreased MMP2 activity.

Partial purification and functional characterization of Ts19 Frag-I, a novel toxin from Tityus serrulatus scorpion venom

BACKGROUND

The yellow scorpion Tityus serrulatus (Ts) is responsible for the highest number of accidents and the most severe scorpion envenoming in Brazil. Although its venom has been studied since the 1950s, it presents a number of orphan peptides that have not been studied so far. The objective of our research was to isolate and identify the components present in the fractions VIIIA and VIIIB of Ts venom, in order to search for a novel toxin. The major isolated toxins were further investigated for macrophage modulation.

METHODS

The fractions VIIIA and VIIIB, obtained from Ts venom cation exchange chromatography, were rechromatographed on a C18 column (4.6 × 250 mm) followed by a reversed-phase chromatography using another C18 column (2.1 × 250 mm). The main eluted peaks were analyzed by MALDI-TOF and Edman's degradation and tested on macrophages.

RESULTS

The previously described toxins Ts2, Ts3-KS, Ts4, Ts8, Ts8 propeptide, Ts19 Frag-II and the novel peptide Ts19 Frag-I were isolated from the fractions VIIIA and VIIIB. Ts19 Frag-I, presenting 58 amino acid residues, a mass of 6,575 Da and a theoretical pI of 8.57, shares high sequence identity with potassium channel toxins (KTx). The toxins Ts4, Ts3-KS and the partially purified Ts19 Frag-I did not produce cytotoxic effects on macrophage murine cells line (J774.1). On the other hand, Ts19 Frag-I induced the release of nitric oxide (NO) by macrophages, while Ts4 and Ts3-KS did not affect the NO production at the tested concentration (50 μg/mL). At the same concentration, Ts19 Frag-I and Ts3-KS increased the production of interleukin-6 (IL-6). Ts19 Frag-I and Ts4 did not induce the release of IL-10, IL-1β or tumor necrosis factor-α by macrophage cells using the tested concentration (50 μg/mL).

CONCLUSIONS

We partially purified and determined the complete sequence and chemical/physical parameters of a new β-KTx, denominated Ts19 Frag-I. The toxins Ts4, Ts3-KS and Ts19 Frag-I showed no cytotoxicity toward macrophages and induced IL-6 release. Ts19 Frag-I also induced the release of NO, suggesting a pro-inflammatory activity.

Enzymatic analysis of venom from Cuban scorpion Rhopalurus junceus

Rhopalurus junceus scorpion venom has been identified as a natural extract with anticancer potential. Interestingly, this scorpion venom does not cause adverse symptoms in humans. However, there is scarce information about its composition and enzymatic activity. In this work, we determined the electrophoretic profile of the venom, the gelatinase and caseinolytic activity, and the phospholipase A2 (PLA2) and hemolytic activity. The effect of different venom doses (6.25, 12.5 and 25 mg/kg) on gastrocnemius muscle was also measured as CK and LDH activity in serum. The presence of hyaluronidase was determined by turbidimetric assay. The effect of different fractions obtained by gel filtration chromatography were evaluated at different concentrations (0.05, 0.1, 0.2, 0.4, 0.6mg/ml) against lung cancer cell A549 and lung normal cell MRC-5 using MTT assay. The electrophoretic profile demonstrated the presence of proteins bands around 67kDa, 43kDa, 18.4kDa and a majority band below 14.3kDa. The venom did not showed caseinolytic, gelatinase, PLA2 and hemolytic activity even at highest venom concentration used in the study. Scorpion venom only showed a significant toxic effect on gastrocnemius muscles identified by CK and LDH release after subcutaneous injection of 12.5 and 25mg/kg. Low molecular weight fractions (<4kDa) induced a significant cytotoxicity in A549 cells while high molecular weight proteins (45-60kDa) were responsible for hyaluronidase activity and toxic effect against MRC-5. Experiments indicate that Rhopalurus junceus scorpion venom has low enzymatic activity, which could contribute to the low toxic potential of this scorpion venom.

Neolignans from Aristolochia elegans as antagonists of the neurotropic effect of scorpion venom

ETHNOPHARMACOLOGICAL RELEVANCE

The high frequency of poisoning by sting or bite from venomous animals has begun to be a serious public health problem in Mexico where scorpion sting is the most common. Because of this, there is the need to seek active substances in plant species with an antagonistic effect against neurotropic activity of scorpion venom. The aim of this work was to demonstrate which of the compounds contained in the n-hexane extract from Aristolochia elegans roots display activity against scorpion venom.

MATERIAL AND METHODS

Antagonist activity displayed by extract, fractions and isolated compounds obtained from Aristolochia elegans was guided by the inhibition of smooth muscle contraction induced by scorpion venom (Centruroides limpidus limpidus) in a model of isolated guinea pig ileum. The neolignans obtained from this extract were isolated and analyzed by chromatographic methods including HPLC. The chemical characterization of these compounds was performed by the analysis of (1)H and (13)C NMR spectra.

RESULTS

The bio-guided chromatographic fractionation allowed us to isolate 4 known neolignans: Eupomatenoid-7 (1), licarin A (2), licarin B (3), eupomatenoid-1 (4) and other new neolignan which was characterized as 2-(3'-hydroxy-4'-methoxyphenyl)-3-methyl-5-[(E)-α-propen-γ-al]-7-methoxy-benzo [b] furan (5). This compound was named as eleganal. Compounds 1 and 2 were purified from the most active fraction AeF3 (EC50 of 149.9μg/mL, Emax of 65.66%). A doses-response analysis of eupomatenoid-7(1) and licarin A(2) allowed us to establish EC50 values (65.96μg/mL and 51.96μg/mL) respectively.

CONCLUSIONS

The antagonistic effect against Centuroides limpidus limpidus scorpion venom displayed by the n-hexane extract from Aristolochia elegans roots is due to the presence of neolignans 1-2 contained in the fraction AeF3. Chemical analysis of fraction AeF2 allowed the isolation of a new compound which was identified as 2-(3'-hydroxy-4'-methoxyphenyl)-3-methyl-5-[(E)-α-propen-γ-al]-7-methoxy-benzo[b]furan (5), denominated as eleganal.

Inhibition effects of scorpion venom extracts (Buthus matensii Karsch) on the growth of human breast cancer MCF-7 cells

BACKGROUND

To observe the inhibition effects of the Buthus matensii Karsch (BmK) scorpion venom extracts on the growth of human breast cancer MCF-7 cells, and to explore its mechanisms.

METHODS

Two common tumor cells (SMMC7721, MCF-7) were examined for the one which wasmore sensitivity to scorpion venom by MTT method. Cell cycle was determined by flow cytometry. Immunocytochemistry was applied to detect apoptosis-related protein Caspase-3 and Bcl-2 levels, while the expression of cell cycle-related protein Cyclin D1 was shown by Western blotting.

RESULTS

Our data indicated that MCF-7 was the more sensitive cell line to scorpion venom. The extracts of scorpion venom could inhibit the growth and proliferation of MCF-7 cells. Furthermore, the extract of scorpion venom induced apoptosis through Caspase-3 up-regulation while Bcl-2 down-regulation in MCF-7 cells. In addition, the extracts of scorpion venom blocked the cells from G0/G1 phase to S phase and decreased cell cycle-related protein Cyclin D1 level after drug intervention compared with the negative control group.

CONCLUSIONS

These results showed that the BmK scorpion venom extracts could inhibit the growth of MCF-7 cells by inducing apoptosis and blocking cell cycle in G0/G1 phase. The BmK scorpion venom extracts will be very valuable for the treatment of breast cancer.

Significant expression of a Chinese scorpion peptide, BmK1, in Escherichia coli through promoter engineering and gene dosage strategy

Heterologous expression is an efficient alternative to conventional extraction to produce a specific Buthus martensii Karsch (BmK) peptide. In this work, BmK1 was successfully expressed in Escherichia coli after genetic codon optimization, but BmK1 content was <6% of total cellular protein. To improve BmK1 expression, a trc promoter library with a wide relative strength was constructed, and three promoters, P_pJF136 (0.55), P_pJF325 (1.29), and P_pJF288 (2.31), were selected to control BmK1 expression. A higher BmK1 expression (>13.9% of total protein) was obtained using a stronger promoter, P_pJF325. Furthermore, a maximum BmK1 content (>21.7% of total protein) was obtained by combining promoter P_pJF325 and three copies of the BmK1 gene. The yield of the purified BmK1 achieved 196.74 mg L⁻¹ in E. coli BL21(DE3) pJF431, which was improved 2.09-fold compared with the control. This was the highest reported production of scorpion peptides in E. coli.

In vitro anticancer effect of venom from Cuban scorpion Rhopalurus junceus against a panel of human cancer cell lines

In Cuba the endemic species of scorpion Rhopalurus junceus has been used in traditional medicine for cancer treatment. However, there is little scientific evidence about its potential in cancer therapy. The effect of a range of scorpion venom concentrations (0.1, 0.25, 0.5, 0.75 and 1mg/ml) against a panel of human tumor cell lines from epithelial (Hela, SiHa, Hep-2, NCI-H292, A549, MDA-MB-231, MDA-MB-468, HT-29), hematopoietic origins (U937, K562, Raji) and normal cells (MRC-5, MDCK, Vero) was determined by the MTT assay. Additionally, the effect of venom on tumor cell death was assayed by Fluorescence microscopy, RT-PCR and western blot. Only the epithelial cancer cells showed significant cell viability reduction, with medium cytotoxic concentration (IC50) ranging from 0.6-1mg/ml, in a concentration-dependent manner. There was no effect on either normal or hematopoietic tumor cells. Scorpion venom demonstrated to induce apoptosis in less sensitive tumor cells (Hela) as evidenced by chromatin condensation, over expression of p53 and bax mRNA, down expression of bcl-2 mRNA and increase of activated caspases 3, 8, 9. In most sensitive tumor cells (A549), scorpion venom induced necrosis evidenced by acridine orange/ethidium bromide fluorescent dyes and down-expression of apoptosis-related genes. We concluded the scorpion venom from R. junceus possessed a selective and differential toxicity against epithelial cancer cells. This is the first report related to biological effect of R. junceus venom against a panel of tumor cells lines. All these results make R. junceus venom as a promise natural product for cancer treatment.

Mass landscapes of seven scorpion species: The first analyses of Australian species with 1,5-DAN matrix

Scorpion venoms have been studied for over fifty years; however, the majority of research has focussed primarily on medically important Buthidae species. Additionally, venoms of the estimated 200 species of scorpion native to Australia have received very little attention. The first venom mass profiles of six non-buthid and one buthid scorpion species are presented herein, four of which are endemic to Australia. While masses under 5 kDa dominated the venoms of all species, the buthid venom contained considerably more masses between 7 and 8 kDa than those of the non-buthids, corroborating the emergent trend that buthids are richer in long-chain neurotoxins than non-buthids. The Australian scorpion venom fractions were also analysed with the relatively new MALDI-ToF matrix 1,5-DAN. Over forty partial sequences were obtained, the majority of which are homologous to scorpion antimicrobials such as opistoporin and IsCT2. Overall, this study is the single most comprehensive mass spectrometric analysis of scorpion venom landscapes to date and provides an insight into untapped Australian species.