Venoms of Iranian Scorpions (Arachnida, Scorpiones) and Their Potential for Drug Discovery

Emerging therapeutic applications of scorpion venom peptides in the Middle East and North Africa: A comprehensive review

The predominantly arid and semi-arid climate, with high temperatures and vast desert areas in the Middle East and North Africa (MENA) region, creates a favorable environment for scorpions, resulting in diversity of species of different genera. Animal venom, particularly scorpion venom, poses a health risk to victims who are envenomed. However, its abundance of bioactive protein molecules also makes it a promising source for new drug development. Numerous studies worldwide have revealed that venom-based molecules exhibit diverse therapeutic activities, including anticancer, antidiabetic, antimicrobial, anti-hypertensive, immunomodulatory, and analgesic properties. Researchers from MENA region are also actively contributing to this global challenge. In this review, we will explore the abundance and diversity of scorpions in the MENA region and examine recent studies on the therapeutic activities of molecules extracted from their venom. Nonetheless, additional research is needed to address the challenges of developing effective natural drugs from scorpion venom.

Management of Recurrent Keratitis as a Complication of Androctonus crassicauda Black Scorpion Sting: A Case Report

Scorpions are a group of arthropods known to be highly toxic to humans. We report the case of a previously healthy 61-year-old male who sustained a sting from an Androctonus crassicauda scorpion to his right eye. The patient was admitted to the intensive care unit (ICU) in a comatose state immediately after the sting. A few days later, he suffered from tearing right-eye pain and loss of vision, which persisted despite initial treatment. The patient was subsequently diagnosed with keratitis and admitted to King Abdullah University Hospital (KAUH). He was prescribed various antibiotics, which initially improved his condition. However, the patient experienced subsequent deterioration and recurrent episodes of keratitis. The patient's visual acuity improved after treatment with a combination of antifungal and antibiotic medications, suggesting a polymicrobial infection. Despite the improvement in his condition, the sting left a central corneal scar, necessitating corneal transplant surgery as a definitive treatment. To the best of our knowledge, this scenario has not been previously documented.

ScorpDb: A Novel Open-Access Database for Integrative Scorpion Toxinology

Scorpion stings are a significant public health concern globally, particularly in tropical and subtropical regions. Scorpion venoms contain a diverse array of bioactive peptides, and different scorpion species around the world typically exhibit varying venom profiles, resulting in a wide range of envenomation symptoms. Despite their harmful effects, scorpion venom peptides hold immense potential for drug development due to their unique characteristics. Therefore, the establishment of a comprehensive database that catalogs scorpions along with their known venom peptides and proteins is imperative in furthering research efforts in this research area. We hereby present ScorpDb, a novel database that offers convenient access to data related to different scorpion species, the peptides and proteins found in their venoms, and the symptoms they can cause. To this end, the ScorpDb database has been primarily advanced to accommodate data on the Iranian scorpion fauna. From there, we propose future community efforts to include a larger diversity of scorpions and scorpion venom components. ScorpDb holds the promise to become a valuable resource for different professionals from a variety of research fields, like toxinologists, arachnologists, and pharmacologists. The database is available at https://www.scorpdb.com/.

First transcriptome analysis of the venom glands of the scorpion Hottentotta zagrosensis (Scorpions: Buthidae) with focus on venom lipolysis activating peptides

Introduction

Scorpion venom is a rich source of biological active peptides and proteins. Transcriptome analysis of the venom gland provides detailed insights about peptide and protein venom components. Following the transcriptome analysis of different species in our previous studies, our research team has focused on the Hottentotta zagrosensis as one of the endemic scorpions of Iran to obtain information about its venom proteins, in order to develop biological research focusing on medicinal applications of scorpion venom components and antivenom production. To gain insights into the protein composition of this scorpion venom, we performed transcriptomic analysis.

Methods

Transcriptomic analysis of the venom gland of H. zagrosensis, prepared from the Khuzestan province, was performed through Illumina paired-end sequencing (RNA-Seq), Trinity de novo assembly, CD-Hit-EST clustering, and annotation of identified primary structures using bioinformatics approaches.

Results

Transcriptome analysis showed the presence of 96.4% of complete arthropod BUSCOs, indicating a high-quality assembly. From total of 45,795,108 paired-end 150 bp trimmed reads, the clustering step resulted in the generation of 101,180 de novo assembled transcripts with N50 size of 1,149 bp. 96,071 Unigenes and 131,235 transcripts had a significant similarity (E-value 1e-3) with known proteins from UniProt, Swissprot, Animal toxin annotation project, and the Pfam database. The results were validated using InterProScan. These mainly correspond to ion channel inhibitors, metalloproteinases, neurotoxins, protease inhibitors, protease activators, Cysteine-rich secretory proteins, phospholipase A enzymes, antimicrobial peptides, growth factors, lipolysis-activating peptides, hyaluronidase, and, phospholipase D. Our venom gland transcriptomic approach identified several biologically active peptides including five LVP1-alpha and LVP1-beta isoforms, which we named HzLVP1_alpha1, HzLVP1_alpha2, HzLVP1_alpha3, HzLVP1_beta1, and HzLVP1_beta and have extremely characterized here.

Discussion

Except for HzLVP1_beta1, all other identified LVP1s are predicted to be stable proteins (instability index <40). Moreover, all isoform of LVP1s alpha and beta subunits are thermostable, with the most stability for HzLVP1_alpha2 (aliphatic index = 71.38). HzLVP1_alpha2 has also the highest half-life. Three-dimensional structure of all identified proteins compacts with three disulfide bridges. The extra cysteine residue may allow the proteins to form a hetero- or homodimer. LVP1 subunits of H. zagrosensis potentially interact with adipose triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL), two key enzymes in regulation of lipolysis in adipocytes, suggesting pharmacological properties of these identified proteins.

Distribution mapping of deadly scorpions in Iran

Scorpion sting is a problem all over the world and becomes an acute problem when it is associated with death. Iran is known as a region with a large number of scorpions and, of course, with many cases of scorpion stings per year. So far, 11 scorpion species in Iran have been identified as dangerous, of which there are only three species for which deaths have been reported. Due to the importance of these three species, we prepared a distribution map of these three types of scorpions and discuss the implications of these findings in the larger context of dangerous scorpion stings in Iran.

Anticancer potentiality of Hottentotta saulcyi scorpion curd venom against breast cancer: an in vitro and in vivo study

Scorpion venom may include pharmacological substances that have the potential to provide benefits. Multiple scientific investigations have shown that particular scorpion venoms induce apoptosis and inhibit the development of cancerous cells. The present study investigated the potential anticancer properties of the crude venom derived from Hottentotta saulcyi (H. saulcyi) on both in vivo mice models and in vitro breast carcinoma cells. The venom of scorpions belonging to the species H. saulcyi was obtained with the application of electrical stimulation at voltages of 8 and 10 V. The determination of the Average Lethal Dose 50 (LD50) was conducted. The present work assessed the in vitro cytotoxicity and morphological characteristics of H. saulcyi venom using fluorescence microscopy, MTT assay, and flow cytometry assessment. Additionally, research was performed to assess the cytotoxic effects in vivo on a mouse model with breast cancer. The examination of MCF-7 cells treated with scorpion venom at a microscopic level revealed the existence of cells undergoing apoptosis. The venom of H. saulcyi has anticancer properties, as shown by the observation that MCF-7 cells had a 62.12% apoptotic rate when exposed to a dose of 1.47 mg/L. Based on the results obtained, it can be shown that the viability of MCF-7 cells has exhibited a substantial reduction (P < 0.01). Furthermore, the findings indicated that the venom of H. saulcyi resulted in a significant increase in the synthesis of TNF-α, IL-6, IL-10, TGF-β, and caspase (P < 0.05). The treatment groups administered with H. saulcyi venom exhibited a significant augmentation in the expression of proapoptotic genes compared to the control group of healthy individuals. The transcription of the BCL2 gene exhibited a statistically significant increase in the healthy control group compared to both the healthy venom-treated group (P < 0.05) and the malignant venom-treated group (P < 0.01). The crude venom of H. saulcyi has considerable promise in demonstrating anticancer properties. Further investigation may be warranted to explore the potential of using H. saulcyi crude venom as a medicinal platform for the prevention of breast cancer.

The need for a refined scorpion antivenom for Iran

Scorpion sting is a medical burden globally but especially frequent hotspots of scorpion biodiversity. In Iran, one of those hotspot countries, many fatalities occur in the South as well as the Southwest and are thought to be caused by Hemiscorpius lepturus. Accordingly, those are used for antivenom production. However, recent surveys revealed that indeed a different species Hemiscorpius acanthocercus is responsible for most accidents in the South, while H. lepturus is primarily causing the fatalities in the Southwest and thus Iranian scorpion antivenom needs to be refined in that respect. Such a refined antivenom would need to cover both species of Hemiscorpius. In response, the Iranian Ministry of Health requested the adjustment of the production line from local antivenom suppliers but until today no action has been taken.

Mass spectrometric analysis of Odonthobuthus Doriae scorpion venom and its non-neutralized fractions after interaction with commercial antivenom

It is believed that antivenoms play a crucial role in neutralizing venoms. However, uncontrolled clinical effects appear in patients stung by scorpions after the injection of antivenom. In this research, non-neutralized components of the venom of the Iranian scorpion Odonthobuthus doriae were analyzed after interacting with the commercial antivenom available in the market. The venom and antivenom interaction was performed, then centrifuged, and the supernatant was analyzed by high-performance liquid chromatography (HPLC). Two peaks of Odonthobuthus doriae venom were observed in the chromatogram of the supernatant. Two components were isolated by HPLC and analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) instruments. Peptide sequencing was done by Liquid Chromatography Quadrupole Time-of-Flight Tandem Mass Spectrometry (LC-Q-TOF MS/MS). Results indicate that the components of scorpion venom mainly have a molecular weight below 10 kDa, consisting of toxic peptides that disrupt the function of sodium and potassium channels. The MALDI-TOF MS results show that two toxic peptides with molecular masses of 6941 Da and 6396 Da were not neutralized by the antivenom. According to the MS/MS sequencing data, the components have been related to peptides A0A5P8U2Q6_MESEU and A0A0U4FP89_ODODO, which belong to the sodium and potassium channels toxins family, respectively.

Bioactive peptides from scorpion venoms: therapeutic scaffolds and pharmacological tools

Evolution and natural selection have endowed animal venoms, including scorpion venoms, with a wide range of pharmacological properties. Consequently, scorpions, their venoms, and/or their body parts have been used since time immemorial in traditional medicines, especially in Africa and Asia. With respect to their pharmacological potential, bioactive peptides from scorpion venoms have become an important source of scientific research. With the rapid increase in the characterization of various components from scorpion venoms, a large number of peptides are identified with an aim of combating a myriad of emerging global health problems. Moreover, some scorpion venom-derived peptides have been established as potential scaffolds helpful for drug development. In this review, we summarize the promising scorpion venoms-derived peptides as drug candidates. Accordingly, we highlight the data and knowledge needed for continuous characterization and development of additional natural peptides from scorpion venoms, as potential drugs that can treat related diseases.

Mass-Spectrometry-Based Lipidome and Proteome Profiling of Hottentotta saulcyi (Scorpiones: Buthidae) Venom

Scorpion venom is a complex secretory mixture of components with potential biological and physiological properties that attracted many researchers due to promising applications from clinical and pharmacological perspectives. In this study, we investigated the venom of the Iranian scorpion Hottentotta saulcyi (Simon, 1880) by applying mass-spectrometry-based proteomic and lipidomic approaches to assess the diversity of components present in the venom. The data revealed that the venom’s proteome composition is largely dominated by Na⁺- and K⁺-channel-impairing toxic peptides, following the enzymatic and non-enzymatic protein families, e.g., angiotensin-converting enzyme, serine protease, metalloprotease, hyaluronidase, carboxypeptidase, and cysteine-rich secretory peptide. Furthermore, lipids comprise ~1.2% of the dry weight of the crude venom. Phospholipids, ether-phospholipids, oxidized-phospholipids, triacylglycerol, cardiolipins, very-long-chain sphingomyelins, and ceramides were the most intensely detected lipid species in the scorpion venom, may acting either independently or synergistically during the envenomation alongside proteins and peptides. The results provide detailed information on the chemical makeup of the venom, helping to improve our understanding of biological molecules present in it, leading to a better insight of the medical significance of the venom, and improving the medical care of patients suffering from scorpion accidents in the relevant regions such as Iran, Iraq, Turkey, and Afghanistan.

Terrestrial venomous animals, the envenomings they cause, and treatment perspectives in the Middle East and North Africa

The Middle East and Northern Africa, collectively known as the MENA region, are inhabited by a plethora of venomous animals that cause up to 420,000 bites and stings each year. To understand the resultant health burden and the key variables affecting it, this review describes the epidemiology of snake, scorpion, and spider envenomings primarily based on heterogenous hospital data in the MENA region and the pathologies associated with their venoms. In addition, we discuss the venom composition and the key medically relevant toxins of these venomous animals, and, finally, the antivenoms that are currently in use to counteract them. Unlike Asia and sub-Saharan Africa, scorpion stings are significantly more common (approximately 350,000 cases/year) than snakebites (approximately 70,000 cases/year) and present the most significant contributor to the overall health burden of envenomings, with spider bites being negligible. However, this review also indicates that there is a substantial lack of high-quality envenoming data available for the MENA region, rendering many of these estimates speculative. Our understanding of the venoms and the toxins they contain is also incomplete, but already presents clear trends. For instance, the majority of snake venoms contain snake venom metalloproteinases, while sodium channel-binding toxins and potassium channel-binding toxins are the scorpion toxins that cause most health-related challenges. There also currently exist a plethora of antivenoms, yet only few are clinically validated, and their high cost and limited availability present a substantial health challenge. Yet, some of the insights presented in this review might help direct future research and policy efforts toward the appropriate prioritization of efforts and aid the development of future therapeutic solutions, such as next-generation antivenoms.

Toxicity and protein composition of venoms of Hottentotta saulcyi, Hottentotta schach and Androctonus crassicauda, three scorpion species collected in Iran

BACKGROUND

Scorpion stings comprise a serious problem throughout the globe, especially in regions where they are more frequent. Despite a recent upsurge of interest in scorpion venoms by various research groups, there remain many challenges.

OBJECTIVE

Therefore, in this study, we aimed to study the toxicity and protein composition of venoms of Hottentotta saulcyi, Hottentotta schach and Androctonus crassicauda, three scorpion species collected in Iran.

MATERIALS AND METHODS

Scorpion species were collected from Esfahan farm scorpion company and maintained in the laboratory in containers that mimic their natural habitat. Venom was extracted from A. crassicauda, H. schach and H. saulcyi by electrical stimulation of 8 and 10 V. The toxicity of each venom was established by using four groups of male Swiss albino mice aged 2 months (weighting 18-20 g) for testing each dose of venom. One group was used as a control. Venom was injected into mice by subcutaneous route. Then, animals were monitored for 24 h and LD₅₀ was estimated by the graphic method of Miller and Tainter. Thus, high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was used to determine amino acids in the venom, and protein concentrations were determined by the Biuret method.

RESULTS

LD₅₀ of scorpion venoms by subcutaneous route was found to be 1.70 mg/kg b.w (A. crassicauda), 1.47 mg/kg b.w (H. saulcyi) and 0.85 mg/kg b.w (H. schach). A. crassicauda, H. saulcyi and H. schach contain 26, 30, and 31 amino acids, respectively. A. crassicauda contains low concentrations of alpha-aminoadipic acid, beta-aminoisobutyric acid, beta-alanine and citrulline. H. saulcyi contains a concentration of hydroxylysine, whereas H. schach has no such concentration. A. crassicauda also had the highest levels of tyrosine and threonine. Only A. crassicauda venom contains a low proportion of proteins (14.80%) compared with those of H. schach (16.26%) and H. saulcyi (16.20%). Albumin content in the venoms was 11.7% (H. saulcyi), 5.4% (H. schach) and 4.4% (A. crassicauda).

CONCLUSION

Scorpions venoms have a variable toxicity and an interesting composition in amino acids and proteins. Work on the development of anti-venom is fundamental.

Discovery of a New Analgesic Peptide, Leptucin, from the Iranian Scorpion, Hemiscorpius lepturus

Hemiscorpius lepturus scorpion stings do not induce considerable pain based on epidemiological surveys conducted in the southwest part of Iran. Accordingly, this study was aimed to identify the analgesic molecule in H. lepturus venom by analyzing a cDNA library of the scorpion venom gland looking for sequences having homology with known animal venom analgesic peptides. The analgesic molecule is a cysteine rich peptide of 55 amino acids. the synthetic peptide was deprotected and refolded. RP-HPLC, Ellman's, and DLS assays confirmed the refolding accuracy. Circular dichroism (CD) showed helix and beta sheet contents. This peptide, called leptucin, demonstrated 95% analgesic activity at the dose of 0.48 mg/kg in hot plate assay. Leptucin at the doses of 0.32, 0.48, and 0.64 mg/kg showed 100% activity in thermal tail flick test. No hemolysis or cytotoxicity was observed at 8 and 16 µg. Histopathology evaluations indicated no hepatotoxicity, nephrotoxicity, and cardiotoxicity. We thus report that leptucin is the analgesic agent of H. lepturus venom. Regarding the high in vivo efficacy of leptucin and the fact it shows no observable toxicity, it could be suggested as a drug lead in a preclinical study of acute pain as well as the study of its mechanism of action.

A Comprehensive Phylogenetic Analysis of the Serpin Superfamily

Serine protease inhibitors (serpins) are found in all kingdoms of life and play essential roles in multiple physiological processes. Owing to the diversity of the superfamily, phylogenetic analysis is challenging and prokaryotic serpins have been speculated to have been acquired from Metazoa through horizontal gene transfer due to their unexpectedly high homology. Here, we have leveraged a structural alignment of diverse serpins to generate a comprehensive 6,000-sequence phylogeny that encompasses serpins from all kingdoms of life. We show that in addition to a central “hub” of highly conserved serpins, there has been extensive diversification of the superfamily into many novel functional clades. Our analysis indicates that the hub proteins are ancient and are similar because of convergent evolution, rather than the alternative hypothesis of horizontal gene transfer. This work clarifies longstanding questions in the evolution of serpins and provides new directions for research in the field of serpin biology.

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.

Cytotoxic Effects of Smp24 and Smp43 Scorpion Venom Antimicrobial Peptides on Tumour and Non-tumour Cell Lines

Smp24 and Smp43 are novel cationic AMPs identified from the venom of the Egyptian scorpion Scorpio maurus palmatus, having potent activity against both Gram-positive and Gram-negative bacteria as well as fungi. Here we describe cytotoxicity of these peptides towards three non-tumour cell lines (CD34+ (hematopoietic stem progenitor from cord blood), HRECs (human renal epithelial cells) and HACAT (human skin keratinocytes) and two acute leukaemia cell lines (myeloid (KG1a) and lymphoid (CCRF-CEM) leukaemia cell lines) using a combination of biochemical and imaging techniques. Smp24 and Smp43 (4–256 µg/mL) decreased the cell viability (as measured by intracellular ATP) of all cells tested, although keratinocytes were markedly less sensitive. Cell membrane leakage as evidenced by the release of lactate dehydrogenase was evident throughout and was confirmed by scanning electron microscope studies.