Scorpion Androctonus Amoreuxi Research Articles

Venomous gland transcriptome and venom proteomic analysis of the scorpion Androctonus amoreuxi reveal new peptides with anti-SARS-CoV-2 activity

The recent COVID-19 pandemic shows the critical need for novel broad spectrum antiviral agents. Scorpion venoms are known to contain highly bioactive peptides, several of which have demonstrated strong antiviral activity against a range of viruses. We have generated the first annotated reference transcriptome for the Androctonus amoreuxi venom gland and used high performance liquid chromatography, transcriptome mining, circular dichroism and mass spectrometric analysis to purify and characterize twelve previously undescribed venom peptides. Selected peptides were tested for binding to the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein and inhibition of the spike RBD – human angiotensin-converting enzyme 2 (hACE2) interaction using surface plasmon resonance-based assays. Seven peptides showed dose-dependent inhibitory effects, albeit with IC50 in the high micromolar range (117–1202 µM). The most active peptide was synthesized using solid phase peptide synthesis and tested for its antiviral activity against SARS-CoV-2 (Lineage B.1.1.7). On exposure to the synthetic peptide of a human lung cell line infected with replication-competent SARS-CoV-2, we observed an IC50 of 200 nM, which was nearly 600-fold lower than that observed in the RBD – hACE2 binding inhibition assay. Our results show that scorpion venom peptides can inhibit the SARS-CoV-2 replication although unlikely through inhibition of spike RBD – hACE2 interaction as the primary mode of action. Scorpion venom peptides represent excellent scaffolds for design of novel anti-SARS-CoV-2 constrained peptides. Future studies should fully explore their antiviral mode of action as well as the structural dynamics of inhibition of target virus-host interactions.

Antinociceptive, antiinflammatory, and antipyretic effects induced by the venom of Egyptian scorpion Androctonus amoreuxi

BackgroundScorpion venom is a very complicated mixture of various peptides/proteins which could induce toxicological and pharmacological responses. This investigation was conducted to evaluate the possible pharmacological properties (analgesic, antipyretic, and antiinflammatory effects) of the Egyptian scorpion venom Androctonus amoreuxi in mice and rats injected intraperitoneally with 1/10 and 1/5 LD50 (0.11 and 0.22 mg/kg for mice; 0.385 and 0.77 mg/kg for rats, respectively).ResultsThe peripheral and central analgesic effect of A. amoreuxi venom was determined using the tests of mice-abdominal writhing and tail immersion of rats, respectively. The antipyretic and antiinflammatory activities were examined using the pyrexia rats model induced by Brewer’s yeast and the paw mice edema induced by carrageenan, respectively. The venom of A. amoreuxi produced significant (p < 0.05) peripheral and central analgesic activity in both animal models. Also, treatment with the scorpion venom showed significant (p < 0.05) dose-independent reduction in pyrexia of rats. More importantly, the venom significantly inhibited mice paw edema induced by carrageenan.ConclusionAccordingly, the present results showed that the venom of this scorpion possesses remarkable pharmacological properties (analgesic, antipyretic, and antiinflammatory activities) on animal models, and might be contain certain peptides responsible for the reported activities.

Potential Anti-Inflammatory Effects of the Egyptian Scorpion (Androctonus amoreuxi) Venom in Rheumatoid Rat Model

Rheumatoid arthritis (RA) is a systemic autoimmune disorder, which takes place in the synovial tissues. This study aims to assess the possibility of using the Egyptian scorpion Androctonus amoreuxi venom (SV) on the treatment and management of RA. The venom was collected from scorpions using electrical stimulation then processed to get crude which was subcutaneously injected to arthritis induced rats. RA was induced in the rats by a single injection of 0.1 ml of Complete Freund's Adjuvant (CFA) at the footpad of the right hind paw of 32 adult male albino rats. Animals were divided into five groups, normal control, RA none treated, SV treated with low and high doses, and methotoxate treated. Results exhibited that SV (0.24 and 0.48 mg/kg) treatment relived pain, improved movement and reduced paw edema and joint swelling volume in arthritic rats. SV had diminished tissue damage in which malondialdehyde (MDA), lactate dehydrogenase (LDH), and creatine kinase (CK) were significantly decreased compared to arthritic rats without side effects in liver, blood, and kidney parameters. Histological examination showed marked improvement in the joint structure after SV treatment. Immunohistochemical staining showed a significant decrease in the expression of nuclear factor-kappa B Cell 65(NFкB-p65), cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in the arthritic joint after treatment with SV. In conclusion, SV possesses therapeutic properties in RA treatment and management due to its analgesic, antioxidant, and anti-inflammatory effects without noticeable side effects.

In vitro and in vivo antitumor effects of the Egyptian scorpion Androctonus amoreuxi venom in an Ehrlich ascites tumor model.

Scorpion venom is a highly complex mixture of about 100–700 different components, where peptides are the major constituents with various biological and pharmacological properties including anticancer activities. In this study, anticancer efficacy of the venom of the Egyptian scorpion Androctonus amoreuxi has been evaluated. In vitro, the human breast cancer MCF-7 cell line was treated with the venom and the IC50 was estimated. In vivo studies, Ehrlich ascites carcinoma (EAC) cells were inoculated into CD-1 mice intraperitoneally to form liquid tumor or subcutaneously to form solid tumor and then treated with intraperitoneal injection with venom (0.22 mg/kg) every other day. The total tumor cells in the ascitic fluid and the size of the solid tumor were assessed after 14 and 30 days, respectively. In addition, the mean survival time (MST), body weight, tumor volume, PCV, viability of tumor cells, CBC, AST, ALP, creatinine, oxidative stress biomarkers (GSH, MDA, PCC), tumor marker Ki67, growth factor VEGF and caspase-3 were measured in normal control, EAC control and venom-treated groups (n = 6). Treatment with venom induced anti-tumor effects against liquid and in solid tumors as indicated by a significant (P < 0.05) reduction in tumor volume/size, count of viable EAC cells, expression of Ki67 and VEGF as well as by remarkable increases in MST and caspase-3 expression as compared to non-treated group. Interestingly, the venom restored the altered hematological and biochemical parameters of tumor-bearing animals and significantly increased their life span. These data indicate to (1) the cytotoxic potential effects of A. amoreuxi on tumor cells via anti-proliferative, apoptotic and anti-angiogenic activities; (2) opening a new avenue for further studies on the anti-cancer effects of this agent.

Fine structure of the stinger, histology and histochemistry of the venom gland in the scorpion Androctonus amoreuxi (Buthidae)

The venom apparatus of the scorpion Androctonus amoreuxi has been identified histologically and histochemically in the present study. The results showed that this apparatus composed of a pair of venom glands and a stinger located in the terminal segment called telson. The stinger of the venom apparatus has been studied by the light microscope and SEM. The stinger, located at the end section of the telson, is sickle-shaped. The venom is ejected through a pair of venom pores on its subterminal portion. Both venom ducts extend along the stinger without contact with each other since they are separated by connective tissue cells. The stinger is covered by cuticle and spines. Each venom gland is covered by a sheath of striated muscle and is lined with extensively folded secretory epithelium that consists of non-secretory and secretory venom-producing cells. The venom-producing cells reacted positively to histochemical tests for carbohydrates and proteins. The outcomes also revealed that the venom-producing cells of both glands produce neutral mucosubstances. The structure and secretion of scorpion venom glands are discussed within the context of the present results.

Characterization of three “Birtoxin-like” toxins from the Androctonus amoreuxi scorpion venom

The venom of the North African scorpion Androctonus amoreuxi (Aam) was analyzed using a combination of gel filtration, C18 reverse phase HPLC together with mass spectrometry analysis and bioassays. Three novel Birtoxin-like (BTX-L) peptides of 58 amino acid residues comprising three disulfide bridges were isolated and chemically characterized. One peptide, AamBTX-L3, induced serious toxic symptoms in mice and was lethal at nanogram quantities using intracerebroventricular injection. The three BTX-L peptides were tested in competition experiments on rat brain synaptosomes against the 125I-labeled “classical” α- and β-toxins of reference, as well as with the 125I-KTX, a voltage-gated potassium channel blocker. Only AamBTX-L3 was able to prevent the equilibrium binding of the β-toxin 125I-Css IV to its receptor site 4 with a IC 50 value of 189 nM. Even if previous electrophysiological data allowed the classification of other BTX-L peptides among the β-type toxins, this report clearly shows that AamBTX-L3 is pharmacologically a β-toxin, which recognizes the voltage-gated Na + (Na v) channels from central mammalian neurons. In order to uncover the residues functionally essential for interaction between the AamBTX-L3 with the putative receptor site of 125I-Css IV on Na v1.2, molecular models of the three novel Aam BTX-L molecules were made and their surfaces were compared to the already described Css IV biologically interactive surfaces. A hypothesis is given that in BTX-L3, three residues found in the α-helix play a key role during target binding.

Full characterization of three toxins from the Androctonus amoreuxi scorpion venom

In this study, we have characterized the immunological and pharmacological properties of the three major α-type toxins from the scorpion Androctonus amoreuxi, AamH1, AamH2 and AamH3, which were previously described as putative toxins from cDNAs [Chen, T. et al., 2003. Regul. Pept. 115, 115–121]. The immunological tests (ELISA, RIA) have demonstrated that AamH1, AamH2 and AamH3 belong to the immunological groups 3 and 4 of α-type toxins. Analysis of the three toxin effects on currents through rat brain (rNav1.2), rat muscle (rNav1.4) and Drosophila (DmNav1) sodium channels expressed in Xenopus oocytes revealed that AamH1 and AamH2, but not AamH3, have anti-insect and anti-mammal activities and can be classified as α-like toxins. While AamH1 removes fast inactivation only in neuronal rNav1.2 channel and has no effect on muscular rNav1.4 channel, AamH2 affects both neuronal rNav1.2 and muscular rNav1.4 channels. AamH3 was lethal to mice by intracerebroventricular injection despite its lack of activity on the neuronal rNav1.2 channel. Finally, we have shown that the A. amoreuxi venom was better neutralized by the antiserum raised against the venom of Buthus occitanus tunetanus than by the antisera raised against scorpion venoms from the same genus Androctonus.

A new Kaliotoxin selective towards Kv1.3 and Kv1.2 but not Kv1.1 channels expressed in oocytes

In this paper were described the purification, the sequencing, and the immunological and biological characterization of a new Kaliotoxin analog, Aam-KTX, from the venom of the scorpion Androctonus amoreuxi. The toxin effects on three cloned Kv channels (Kv1.1, Kv1.2, and Kv1.3) were investigated in Xenopus oocytes using electrophysiology experiments. The Aam-KTX preference for Kv1.3 channel versus Kv1.2 was expected (EC50 values, 1.1±0.02 and 10.4±1.5nM, respectively) but its total inefficacity on Kv1.1 was very surprising. 3D molecular modeling of Aam-KTX brought putative answers to this difference in selectivity.

Teratogenicity in the rat of the venom from the scorpion Androctonus amoreuxi (Aud. & Sav.)

A. amoreuxi venom caused a high foetal resorption rate in rats, particularly when injected on days 9–11 of gestation. Vertebral and ossification defects and foetal weight loss were observed in many of the viable foetuses obtained from mothers treated with scorpion venom. Treatment of the rats with phentolamine in addition to the venom significantly reduced the venom-induced hyperglycemia. It also conferred some protection against foetal resorption but had only a slight effect on chondrification or foetal weight loss. This shows that hyperglycemia might be responsible for foetal mortality, but alone is not a decisive factor in the effect of the venom on the chondrification process. Treatment of the rats with triamterene reduced the foetal resorption rate and significantly decreased the effects of the venom on chondrification. However, marked stippling was observed in the long bones and was ascribed to marked mobilization of ionized calcium in the foetus. Foetuses removed from rats treated with phentolamine or triamterene in addition to the venom, however, showed flattened and depressed skulls, possibly from a missing 1st cervical vertebra or failure of the occiptal fontanel to close. Treatment of the rats with the scorpion venom over a longer period of time and starting at an earlier time of gestation (days 7–14) caused total foetal resorption, which may be due to inhibition of histamine formation by the venom. The teratogenic effect of the venom appears to be the result of its metabolic effect and action on body electrolytes of the maternal animal, rather than to a direct effect on the foetuses. This was evidenced from experiments with labelled venom, where only a small fraction (0.08-0.33%) was detected in foetuses or placenta.

Pharmacokinetics of 125I-labelled antivenin to the venom from the scorpion Androctonus amoreuxi

An antivenin for A. amoreuxi venom was prepared by hyperimmunizing rabbits. The globulin fraction was separated and purified and the immunogloblin fraction (chiefly IgG) separated, purified and radioiodinated. Using the immunodifussion technique, seven prominent and two faint precipitin bands were found with both the crude antivenin and the globulin fraction and four prominent and one faint precipitin bands with the immunoglobulin fraction, when tested against the venom. Ten milligrams of the immunoglobulin fraction (Ig) protected the mice from the lethal action of a dose of the venom equal to 5 times the ld 50. The corresponding values for the globulin fraction and the crude antivenin were 70 mg and 4 ml, respectively. The pharmacokinetic profile of the labelled Ig was determined following rapid i.v. injection into rabbits. The data obtained showed an excellent fit to a triexponential equation of the form: C p,t= Pe − πt + Ae − αt ;+ Be − βt ; where C p,t is the antivenin concentration in the blood at time t, π, α and β are hybrid rate constants and P, A and B are the corresponding zero time intercepts. This equation represents a pharmacokinetic model consisting of a central compartment from which distribution to a rapidly equilibrating “shallow” compartment and a slowly equilibrating “deep” compartment takes place, with elimination taking place from the central compartment. The apparent half-lives for the early declining phases were 1.06 and 9.63 hr for the rapidly and slowly equilibrating compartments, respectively. The overall elimination half life was 43.3 hr. The ineffectiveness of serotherapy with scorpion antiven injected several hours after scorpion sting might be due to differences in distribution half lives.

Pharmacological studies of scorpion ( Androctonus amoreuxi Aud. & Sav.) venom

Venom from the scorpion Androctonus amoreuxi was fractionated into eight components by cellulose acetate electrophoresis, using barbitone buffer pH 8·6. Only one of the electrophoretic fractions was lethal in mice. The ld 50 of the venom following i.m. injection into mice was estimated to be 0·88 ± 0·06 mg per kg. The cardiovascular effects of the venom appeared to be mediated through stimulation of both parts of the autonomic nervous system with predominance of sympathetic stimulation, and release of tissue catecholamines. The venom markedly decreased the tone of the spontaneously contracting rat uterus in all states of uterine function except in pregnancy where it produced a stimulant effect. The uterine inhibitory effect of the venom is probably due to stimulation of the β-adrenergic receptors as it was blocked by propranolol. The venom first increased the amplitude and then blocked the twitches of the rat phrenic nerve-hemidiaphragm and caused contracture and decrease of twitch height of the tibialis anterior muscle preparation. Of the various fractions separated by cellulose acetate electrophoresis, only three fractions showed activity on the various preparations studied.