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1.
Zhejiang Da Xue Xue Bao Yi Xue Ban ; 53(2): 194-200, 2024 Apr 25.
Article in English, Chinese | MEDLINE | ID: mdl-38268403

ABSTRACT

OBJECTIVES: To isolate a potassium ion channel Kv4.1 inhibitor from centipede venom, and to determine its sequence and structure. METHODS: Ion-exchange chromatography and reversed-phase high-performance liquid chromatography were performed to separate and purify peptide components of centipede venom, and their inhibiting effect on Kv4.1 channel was determined by whole-cell patch clamp recording. The molecular weight of isolated peptide Kv4.1 channel inhibitor was identified with matrix assisted laser desorption ionization-time-of-flight mass spectrometry; its primary sequence was determined by Edman degradation sequencing and two-dimensional mass spectrometry; its structure was established based on iterative thread assembly refinement online analysis. RESULTS: A peptide SsTx-P2 was separated from centipede venom with the molecular weight of 6122.8, and its primary sequence consists of 53 amino acid residues NH2-ELTWDFVRTCCKLFPDKSECTKACATEFTGGDESRLKDVWPRKLRSGDSRLKD-OH. Peptide SsTx-P2 potently inhibited the current of Kv4.1 channel transiently transfected in HEK293 cell, with 1.0 µmol/L SsTx-P2 suppressing 95% current of Kv4.1 channel. Its structure showed that SsTx-P2 shared a conserved helical structure. CONCLUSIONS: The study has isolated a novel peptide SsTx-P2 from centipede venom, which can potently inhibit the potassium ion channel Kv4.1 and displays structural conservation.


Subject(s)
Amino Acid Sequence , Arthropod Venoms , Shal Potassium Channels , Animals , Humans , Arthropod Venoms/chemistry , Arthropod Venoms/pharmacology , Molecular Sequence Data , Peptides/pharmacology , Peptides/isolation & purification , Peptides/chemistry , Potassium Channel Blockers/pharmacology , Potassium Channel Blockers/isolation & purification , Potassium Channel Blockers/chemistry , Shal Potassium Channels/antagonists & inhibitors , Chilopoda/chemistry
2.
Toxicon ; 238: 107588, 2024 Feb 01.
Article in English | MEDLINE | ID: mdl-38147939

ABSTRACT

Pest insects pose a heavy burden on global agricultural industries with small molecule insecticides being predominantly used for their control. Unwanted side effects and resistance development plagues most small molecule insecticides such as the neonicotinoids, which have been reported to be harmful to honeybees. Bioinsecticides like Bacillus thuringiensis (Bt) toxins can be used as environmentally-friendly alternatives. Arachnid venoms comprise another promising source of bioinsecticides, containing a multitude of selective and potent insecticidal toxins. Unfortunately, no standardised insect models are currently available to assess the suitability of insecticidal agents under laboratory conditions. Thus, we aimed to develop a laboratory model that closely mimics field conditions by employing a leaf disk assay (LDA) for oral application of insecticidal agents in a bioassay tray format. Neonate larvae of the cotton bollworm (Helicoverpa armigera) were fed with soybean (Glycine max) leaves that were treated with different insecticidal agents. We observed dose-dependent insecticidal effects for Bt toxin and the neonicotinoid insecticide imidacloprid, with imidacloprid exhibiting a faster response. Furthermore, we identified several insecticidal arachnid venoms that were active when co-applied with sub-lethal doses of Bt toxin. We propose the H. armigera LDA as a suitable tool for assessing the insecticidal effects of insecticidal agents against lepidopterans.


Subject(s)
Arthropod Venoms , Bacillus thuringiensis , Insecticides , Moths , Neonicotinoids , Nitro Compounds , Toxins, Biological , Humans , Infant, Newborn , Animals , Insecticides/toxicity , Glycine max , Helicoverpa armigera , Bacillus thuringiensis Toxins/pharmacology , Larva , Insecta , Toxins, Biological/pharmacology , Arthropod Venoms/pharmacology , Biological Assay , Plant Leaves , Bacterial Proteins/pharmacology , Hemolysin Proteins/toxicity , Endotoxins , Pest Control, Biological , Insecticide Resistance
3.
Toxins (Basel) ; 15(4)2023 04 03.
Article in English | MEDLINE | ID: mdl-37104206

ABSTRACT

Infections caused by multidrug-resistant Acinetobacter baumannii (MDR-Ab) have become a public health emergency. Due to the small therapeutic arsenal available to treat these infections, health agencies have highlighted the importance of developing new antimicrobials against MDR-Ab. In this context, antimicrobial peptides (AMPs) stand out, and animal venoms are a rich source of these compounds. Here, we aimed to summarize the current knowledge on the use of animal venom-derived AMPs in the treatment of MDR-Ab infections in vivo. A systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The eight studies included in this review identified the antibacterial activity of eleven different AMPs against MDR-Ab. Most of the studied AMPs originated from arthropod venoms. In addition, all AMPs are positively charged and rich in lysine residues. In vivo assays showed that the use of these compounds reduces MDR-Ab-induced lethality and bacterial load in invasive (bacteremia and pneumonia) and superficial (wounds) infection models. Moreover, animal venom-derived AMPs have pleiotropic effects, such as pro-healing, anti-inflammatory, and antioxidant activities, that help treat infections. Animal venom-derived AMPs are a potential source of prototype molecules for the development of new therapeutic agents against MDR-Ab.


Subject(s)
Acinetobacter Infections , Acinetobacter baumannii , Arthropod Venoms , Animals , Antimicrobial Peptides , Acinetobacter Infections/drug therapy , Acinetobacter Infections/microbiology , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Anti-Bacterial Agents/chemistry , Arthropod Venoms/pharmacology , Drug Resistance, Multiple, Bacterial , Microbial Sensitivity Tests
4.
Molecules ; 27(14)2022 Jul 11.
Article in English | MEDLINE | ID: mdl-35889297

ABSTRACT

Venoms are a complex cocktail of biologically active molecules, including peptides, proteins, polyamide, and enzymes widely produced by venomous organisms. Through long-term evolution, venomous animals have evolved highly specific and diversified peptides and proteins targeting key physiological elements, including the nervous, blood, and muscular systems. Centipedes are typical venomous arthropods that rely on their toxins primarily for predation and defense. Although centipede bites are frequently reported, the composition and effect of centipede venoms are far from known. With the development of molecular biology and structural biology, the research on centipede venoms, especially peptides and proteins, has been deepened. Therefore, we summarize partial progress on the exploration of the bioactive peptides and proteins in centipede venoms and their potential value in pharmacological research and new drug development.


Subject(s)
Arthropod Venoms , Arthropods , Animals , Arthropod Venoms/chemistry , Arthropod Venoms/pharmacology , Arthropods/chemistry , Chilopoda , Peptides/chemistry , Proteins/chemistry , Venoms/metabolism
5.
Toxins (Basel) ; 14(1)2022 01 14.
Article in English | MEDLINE | ID: mdl-35051034

ABSTRACT

Linear cationic venom peptides are antimicrobial peptides (AMPs) that exert their effects by damaging cell membranes. These peptides can be highly specific, and for some, a significant therapeutic value was proposed, in particular for treatment of bacterial infections. A prolific source of novel AMPs are arthropod venoms, especially those of hitherto neglected groups such as pseudoscorpions. In this study, we describe for the first time pharmacological effects of AMPs discovered in pseudoscorpion venom. We examined the antimicrobial, cytotoxic, and insecticidal activity of full-length Checacin1, a major component of the Chelifer cancroides venom, and three truncated forms of this peptide. The antimicrobial tests revealed a potent inhibitory activity of Checacin1 against several bacteria and fungi, including methicillin resistant Staphylococcus aureus (MRSA) and even Gram-negative pathogens. All peptides reduced survival rates of aphids, with Checacin1 and the C-terminally truncated Checacin11-21 exhibiting effects comparable to Spinosad, a commercially used pesticide. Cytotoxic effects on mammalian cells were observed mainly for the full-length Checacin1. All tested peptides might be potential candidates for developing lead structures for aphid pest treatment. However, as these peptides were not yet tested on other insects, aphid specificity has not been proven. The N- and C-terminal fragments of Checacin1 are less potent against aphids but exhibit no cytotoxicity on mammalian cells at the tested concentration of 100 µM.


Subject(s)
Anti-Infective Agents , Arthropod Proteins , Arthropod Venoms , Cytotoxins , Insecticides , Amino Acid Sequence , Animals , Anti-Infective Agents/chemistry , Anti-Infective Agents/pharmacology , Anti-Infective Agents/toxicity , Aphids/drug effects , Arachnida , Arthropod Proteins/chemistry , Arthropod Proteins/pharmacology , Arthropod Proteins/toxicity , Arthropod Venoms/chemistry , Arthropod Venoms/pharmacology , Arthropod Venoms/toxicity , Cytotoxins/chemistry , Cytotoxins/pharmacology , Cytotoxins/toxicity , Dogs , Insecticides/chemistry , Insecticides/pharmacology , Insecticides/toxicity , Madin Darby Canine Kidney Cells , Sequence Alignment
6.
Sci Rep ; 10(1): 18395, 2020 10 27.
Article in English | MEDLINE | ID: mdl-33110124

ABSTRACT

Contact with stinging spines venom from several Lepidoptera larvae may result in skin lesions. In Mexico, envenomation outbreaks caused by Megalopyge opercularis were reported between 2015 and 2016. The aim of this study was to identify the venomous caterpillars in Nuevo Leon, Mexico and evaluate several biological activities of their hemolymph (HEV) and spine setae (SSV) venoms. M. opercularis was identified by cytochrome oxidase subunit (COI) designed primers. HEV and SSV extracts cytotoxic activity was assessed on the L5178Y-R lymphoma cell line. For apoptotic cells number and apoptosis, cells were stained with acridine orange/ethidium bromide and validated by DNA fragmentation. Human peripheral blood mononuclear cells (hPBMC) cytokine response to the extracts was measured by the cytometric bead array assay. Extracts effect on pro-coagulation activity on human plasma was also evaluated. HEV and SSV extracts significantly inhibited (p < 0.01) up to 63% L5178Y-R tumor cell growth at 125-500 µg/mL, as compared with 43% of Vincristine. About 79% extracts-treated tumor cells death was caused by apoptosis. Extracts stimulated (p < 0.01) up to 60% proliferation of resident murine lymphocytes, upregulated IL-1ß, IL-6, IL-8, and TNF-α production by hPBMC, and showed potent pro-coagulant effects. The pharmacological relevance of these venoms is discussed.


Subject(s)
Anti-Inflammatory Agents/pharmacology , Antineoplastic Agents/pharmacology , Arthropod Venoms/pharmacology , Coagulants/pharmacology , Hemolymph/metabolism , Animals , Cell Proliferation/drug effects , Cytokines/metabolism , Humans , T-Lymphocytes/drug effects , T-Lymphocytes/metabolism
7.
Curr Allergy Asthma Rep ; 20(9): 48, 2020 06 16.
Article in English | MEDLINE | ID: mdl-32548726

ABSTRACT

PURPOSE OF REVIEW: In Hymenoptera venom allergy, the research focus has moved from whole venoms to individual allergenic molecules. Api m 10 (icarapin) has been described as a major allergen of honeybee venom (HBV) with potentially high relevance for diagnostics and therapy of venom allergy. Here, we review recent studies on Api m 10 characteristics as well as its role in component-resolved diagnostics and potential implications for venom-specific immunotherapy (VIT). RECENT FINDINGS: Api m 10 is a major allergen of low abundance in HBV. It is an obviously unstable protein of unknown function that exhibits homologs in other insect species. Despite its low abundance in HBV, 35 to 72% of HBV-allergic patients show relevant sensitization to this allergen. Api m 10 is a marker allergen for HBV sensitization, which in many cases can help to identify primary sensitization to HBV and, hence, to discriminate between genuine sensitization and cross-reactivity. Moreover, Api m 10 might support personalized risk stratification in VIT, as dominant sensitization to Api m 10 has been identified as risk factor for treatment failure. This might be of particular importance since Api m 10 is strongly underrepresented in some therapeutic preparations commonly used for VIT. Although the role of Api m 10 in HBV allergy and tolerance induction during VIT is not fully understood, it certainly is a useful tool to unravel primary sensitization and individual sensitization profiles in component-resolved diagnostics (CRD). Moreover, a potential of Api m 10 to contribute to personalized treatment strategies in HBV allergy is emerging.


Subject(s)
Allergens/therapeutic use , Arthropod Venoms/therapeutic use , Bee Venoms/therapeutic use , Desensitization, Immunologic/methods , Hymenoptera/pathogenicity , Insect Bites and Stings/therapy , Animals , Arthropod Venoms/pharmacology , Bee Venoms/pharmacology , Humans , Risk Factors
8.
Toxins (Basel) ; 12(4)2020 04 05.
Article in English | MEDLINE | ID: mdl-32260499

ABSTRACT

Centipedes are among the oldest venomous arthropods that use their venom to subdue the prey. The major components of centipede venom are a variety of low-molecular-weight peptide toxins that have evolved to target voltage-gated ion channels to interfere with the central system of prey and produce pain or paralysis for efficient hunting. Peptide toxins usually contain several intramolecular disulfide bonds, which confer chemical, thermal and biological stability. In addition, centipede peptides generally have novel structures and high potency and specificity and therefore hold great promise both as diagnostic tools and in the treatment of human disease. Here, we review the centipede peptide toxins with reported effects on ion channels, including Nav, Kv, Cav and the nonselective cation channel polymodal transient receptor potential vanilloid 1 (TRPV1).


Subject(s)
Arthropod Proteins/pharmacology , Arthropod Venoms/pharmacology , Bites and Stings/metabolism , Chilopoda/metabolism , Drug Discovery , Ion Channels/drug effects , Membrane Transport Modulators/pharmacology , Animals , Arthropod Proteins/metabolism , Arthropod Venoms/metabolism , Humans , Ion Channels/metabolism , Membrane Transport Modulators/metabolism , Protein Conformation , Signal Transduction , Structure-Activity Relationship
9.
Toxins (Basel) ; 12(2)2020 01 25.
Article in English | MEDLINE | ID: mdl-31991714

ABSTRACT

Arthropods comprise a predominant and well-succeeded phylum of the animal kingdom that evolved and diversified in millions of species grouped in four subphyla, namely, Chelicerata (arachnids), Crustacea, Myriapoda (centipedes), and Hexapoda (insects) [...].


Subject(s)
Arthropod Venoms , Peptides , Animals , Arthropod Venoms/chemistry , Arthropod Venoms/pharmacology , Arthropod Venoms/therapeutic use , Arthropod Venoms/toxicity , Insecticides/chemistry , Insecticides/pharmacology , Insecticides/therapeutic use , Insecticides/toxicity , Peptides/chemistry , Peptides/pharmacology , Peptides/therapeutic use , Peptides/toxicity
10.
Zool Res ; 41(2): 138-147, 2020 Mar 18.
Article in English | MEDLINE | ID: mdl-31945809

ABSTRACT

As the oldest venomous animals, centipedes use their venom as a weapon to attack prey and for protection. Centipede venom, which contains many bioactive and pharmacologically active compounds, has been used for centuries in Chinese medicine, as shown by ancient records. Based on comparative analysis, we revealed the diversity of and differences in centipede toxin-like molecules between Scolopendra mojiangica, a substitute pharmaceutical material used in China, and S. subspinipes mutilans. More than 6 000 peptides isolated from the venom were identified by electrospray ionization-tandem mass spectrometry (ESI-MS/MS) and inferred from the transcriptome. As a result, in the proteome of S. mojiangica, 246 unique proteins were identified: one in five were toxin-like proteins or putative toxins with unknown function, accounting for a lower percentage of total proteins than that in S. mutilans. Transcriptome mining identified approximately 10 times more toxin-like proteins, which can characterize the precursor structures of mature toxin-like peptides. However, the constitution and quantity of the toxin transcripts in these two centipedes were similar. In toxicity assays, the crude venom showed strong insecticidal and hemolytic activity. These findings highlight the extensive diversity of toxin-like proteins in S. mojiangica and provide a new foundation for the medical-pharmaceutical use of centipede toxin-like proteins.


Subject(s)
Arthropod Venoms/pharmacology , Arthropods/chemistry , Peptides/chemistry , Animals , China , Peptides/pharmacology , Spectrometry, Mass, Electrospray Ionization , Tandem Mass Spectrometry , Transcriptome
11.
Sci Rep ; 9(1): 14088, 2019 10 01.
Article in English | MEDLINE | ID: mdl-31575961

ABSTRACT

Inhibitors targeting ion channels are useful tools for studying their functions. Given the selectivity of any inhibitor for a channel is relative, more than one inhibitor of different affinities may be used to help identify the channel in a biological preparation. Here, we describe a family of small proteins in centipede venoms that inhibit the pore (hKir6.2) of a human ATP-sensitive K+ channel (hKATP). While the traditional peptide-sequencing service gradually vanishes from academic institutions, we tried to identify the sequences of inhibitory proteins purified from venoms by searching the sequences of the corresponding transcriptomes, a search guided by the key features of a known hKir6.2 inhibitor (SpTx1). The candidate sequences were cross-checked against the masses of purified proteins, and validated by testing the activity of recombinant proteins against hKir6.2. The four identified proteins (SsdTx1-3 and SsTx) inhibit hKATP channels with a Kd of <300 nM, compared to 15 nM for SpTx1. SsTx has previously been discovered to block human voltage-gated KCNQ K+ channels with a 2.5 µM Kd. Given that SsTx inhibits hKir6.2 with >10-fold lower Kd than it inhibits hKCNQ, SsTx may not be suitable for probing KCNQ channels in a biological preparation that also contains more-SsTx-sensitive KATP channels.


Subject(s)
Arthropod Venoms/pharmacology , Arthropods , Potassium Channels, Inwardly Rectifying/antagonists & inhibitors , Animals , Arthropod Venoms/genetics , Arthropod Venoms/isolation & purification , Chromatography, High Pressure Liquid , Humans , Transcriptome/genetics
12.
Toxins (Basel) ; 11(10)2019 09 25.
Article in English | MEDLINE | ID: mdl-31557900

ABSTRACT

Arthropoda is a phylum of invertebrates that has undergone remarkable evolutionary radiation, with a wide range of venomous animals. Arthropod venom is a complex mixture of molecules and a source of new compounds, including antimicrobial peptides (AMPs). Most AMPs affect membrane integrity and produce lethal pores in microorganisms, including protozoan pathogens, whereas others act on internal targets or by modulation of the host immune system. Protozoan parasites cause some serious life-threatening diseases among millions of people worldwide, mostly affecting the poorest in developing tropical regions. Humans can be infected with protozoan parasites belonging to the genera Trypanosoma, Leishmania, Plasmodium, and Toxoplasma, responsible for Chagas disease, human African trypanosomiasis, leishmaniasis, malaria, and toxoplasmosis. There is not yet any cure or vaccine for these illnesses, and the current antiprotozoal chemotherapeutic compounds are inefficient and toxic and have been in clinical use for decades, which increases drug resistance. In this review, we will present an overview of AMPs, the diverse modes of action of AMPs on protozoan targets, and the prospection of novel AMPs isolated from venomous arthropods with the potential to become novel clinical agents to treat protozoan-borne diseases.


Subject(s)
Anti-Infective Agents/pharmacology , Arthropod Venoms/analysis , Leishmania/drug effects , Peptides/pharmacology , Plasmodium/drug effects , Trypanosoma/drug effects , Anti-Infective Agents/therapeutic use , Arthropod Venoms/pharmacology , Humans , Immune System/drug effects , Peptides/therapeutic use
13.
Channels (Austin) ; 13(1): 264-286, 2019 12.
Article in English | MEDLINE | ID: mdl-31237176

ABSTRACT

Calcium entry is central to the functional processes in mast cells and basophils that contribute to the induction and maintenance of inflammatory responses. Mast cells and basophils express an array of calcium channels, which mediate responses to diverse stimuli triggered by small bioactive molecules, physicochemical stimuli and immunological inputs including antigens and direct immune cell interactions. These cells are also highly responsive to certain venoms (such as Hymenoptera envenomations), which cause histamine secretion, cytokine release and an array of pro-inflammatory functional responses. There are gaps in our understanding of the coupling of venom exposure to specific signaling pathways such as activation of calcium channels. In the present study, we performed a current survey of a model mast cell line selected for its pleiotropic responsiveness to multiple pro-inflammatory inputs. As a heterogenous stimulus, Hymenoptera venom activates multiple classes of conductance at the population level but tend to lead to the measurement of only one type of conductance per cell, despite the cell co-expressing multiple channel types. The data show that ICRAC, IARC, and TRPV-like currents are present in the model mast cell populations and respond to venom exposure. We further assessed individual venom components, specifically secretagogues and arachidonic acid, and identified the conductances associated with these stimuli in mast cells. Single-cell calcium assays and immunofluorescence analysis show that there is heterogeneity of channel expression across the cell population, but this heterogeneity does not explain the apparent selectivity for specific channels in response to exposure to venom as a composite stimulus.


Subject(s)
Arthropod Venoms/pharmacology , Bites and Stings/immunology , Hymenoptera/physiology , Mast Cells/immunology , Animals , Arthropod Venoms/immunology , Arthropod Venoms/toxicity , Histamine/immunology , Humans , Hymenoptera/immunology , Mast Cells/drug effects , TRPV Cation Channels/genetics , TRPV Cation Channels/immunology
14.
Toxins (Basel) ; 11(2)2019 02 01.
Article in English | MEDLINE | ID: mdl-30717088

ABSTRACT

It was recently discovered that Ssm Spooky Toxin (SsTx) with 53 residues serves as a key killer factor in red-headed centipede's venom arsenal, due to its potent blockage of the widely expressed KCNQ channels to simultaneously and efficiently disrupt cardiovascular, respiratory, muscular, and nervous systems, suggesting that SsTx is a basic compound for centipedes' defense and predation. Here, we show that SsTx also inhibits KV1.3 channel, which would amplify the broad-spectrum disruptive effect of blocking KV7 channels. Interestingly, residue R12 in SsTx extends into the selectivity filter to block KV7.4, however, residue K11 in SsTx replaces this ploy when toxin binds on KV1.3. Both SsTx and its mutant SsTx_R12A inhibit cytokines production in T cells without affecting the level of KV1.3 expression. The results further suggest that SsTx is a key molecule for defense and predation in the centipedes' venoms and it evolves efficient strategy to disturb multiple physiological targets.


Subject(s)
Arthropod Venoms/pharmacology , KCNQ Potassium Channels/antagonists & inhibitors , Kv1.3 Potassium Channel/antagonists & inhibitors , Potassium Channel Blockers/pharmacology , Animals , Arthropods , CHO Cells , Cricetulus , Cytokines/metabolism , HEK293 Cells , Humans , KCNQ Potassium Channels/physiology , Kv1.3 Potassium Channel/physiology , T-Lymphocytes/drug effects , T-Lymphocytes/metabolism
15.
Toxicon ; 158: 33-37, 2019 Feb.
Article in English | MEDLINE | ID: mdl-30496730

ABSTRACT

The millions of extant arthropod species are testament to their evolutionary success that can at least partially be attributed to venom usage, which evolved independently in at least 19 arthropod lineages. While some arthropods primarily use venom for predation (e.g., spiders and centipedes) or defense (e.g., bees and caterpillars), it can also have more specialised functions (e.g. in parasitoid wasps to paralyse arthropods for their brood to feed on) or even a combination of functions (e.g. the scorpion Parabuthus transvaalicus can deliver a prevenom for predator deterrence and a venom for predation). Most arthropod venoms are complex cocktails of water, salts, small bioactive molecules, peptides, enzymes and larger proteins, with peptides usually comprising the majority of toxins. Some spider venoms have been reported to contain >1000 peptide toxins, which function as combinatorial libraries to provide an evolutionary advantage. The astounding diversity of venomous arthropods multiplied by their enormous toxin arsenals results in an almost infinite resource for novel bioactive molecules. The main challenge for exploiting this resource is the small size of most arthropods, which can be a limitation for current venom extraction techniques. Fortunately, recent decades have seen an incredible improvement in transcriptomic and proteomic techniques that have provided increasing sensitivity while reducing sample requirements. In turn, this has provided a much larger variety of arthropod venom compounds for potential applications such as therapeutics, molecular probes for basic research, bioinsecticides or anti-parasitic drugs. This special issue of Toxicon aims to cover the breadth of arthropod venom research, including toxin evolution, pharmacology, toxin discovery and characterisation, toxin structures, clinical aspects, and potential applications.


Subject(s)
Arthropod Venoms/chemistry , Arthropod Venoms/toxicity , Arthropods/chemistry , Animals , Arthropod Venoms/pharmacology , Biological Evolution , Peptides/chemistry
16.
Curr Opin Insect Sci ; 30: 93-98, 2018 12.
Article in English | MEDLINE | ID: mdl-30553492

ABSTRACT

Insect toxins comprise a diverse array of chemicals ranging from small molecules, polyamines and peptide toxins. Many target nervous system and neuromuscular ion channels and so rapidly affect the behaviour of animals to which the toxin is applied or injected. Other modes of action have also been identified. Wasps, bees, flies, beetles and ants generate a rich arsenal of channel-active toxins, some of which offer selective pharmacological probes that target particular ion channels, while others act on more than one type of channel. Philanthotoxins from the digger wasp have been fruitful in adding to our understanding of ligand-gated ion channels both in the nervous system and at neuromuscular junctions. Fire ants produce the toxic alkaloid solenopsin, a molecule which has stimulated attempts to generate synthetic compounds with insecticidal activity. Apamin from bee venom targets calcium-activated potassium channels, which can in turn influence the release of neuropeptides. Melittin, another bee venom component, is a membrane-acting peptide. The saliva of the assassin bug contains toxins that target the voltage-gated calcium channels of their insect prey. Certain beetles produce diamphotoxin, a haemolytic peptide toxin with traditional use as an arrow poison and others generate leptinotarsin with similar properties. Mastoparan is a powerful peptide toxin present in the venom of wasps. Its toxic actions can be engineered out leaving a potent antimicrobial molecule of interest. In this short review we describe the actions of selected insect toxins and evaluate their potential as neuroactive pharmacological tools, candidate lead molecules for insect control and therapeutic candidates with potential antimicrobial, antiviral and anti-cancer applications.


Subject(s)
Insect Control/instrumentation , Insecta/drug effects , Toxins, Biological/chemistry , Toxins, Biological/pharmacology , Animals , Arthropod Venoms/chemistry , Arthropod Venoms/pharmacology
17.
Toxicon ; 154: 60-68, 2018 Nov.
Article in English | MEDLINE | ID: mdl-30273703

ABSTRACT

Centipede bites are usually characterized by mildly to moderately painful encounters with humans, however, they are relatively infrequent. The vast majority of centipede envenomations do not cause severe symptoms and only in very rare cases more serious symptoms such as myocardial ischemia and infarction, hematuria, hemoglobinuria, rhabdomyolysis, hemorrhage, pruritus, eosinophilic cellulitis, as well as anaphylaxis are observed. More prevalent are symptoms including pain, paresthesia, lethargy, localized necrosis, headache, dizziness and nausea. The numerous symptoms and complications elicited by these envenomations indicate that centipede venom possesses an arsenal of chemical components with functional diversity. Centipede venom is a rich and complex natural source of bioactive proteins, peptides and other small molecules that aid in predation or defense. The venom can induce myotoxic, cardiotoxic, neurotoxic and other toxic effects. The constituents target different cellular processes and pathways which in turn trigger a cascade of physiological reactions in the victim. The venom components are potent and selective on peripheral targets; thus, they are valuable in studying the molecular basis of these envenomation symptoms and complications. This review highlights the clinical importance of centipede envenomation and the recent discoveries on the underlying molecular mechanisms of the resulting symptoms which is crucial in therapy.


Subject(s)
Arthropod Venoms/chemistry , Arthropod Venoms/pharmacology , Bites and Stings/etiology , Animals , Arthropod Venoms/poisoning , Arthropod Venoms/toxicity , Arthropods/chemistry , Humans
18.
J Gen Physiol ; 150(7): 969-976, 2018 07 02.
Article in English | MEDLINE | ID: mdl-29844136

ABSTRACT

The adenosine triphosphate (ATP)-sensitive (KATP) channels in pancreatic ß cells couple the blood glucose level to insulin secretion. KATP channels in pancreatic ß cells comprise the pore-forming Kir6.2 and the modulatory sulfonylurea receptor 1 (SUR1) subunits. Currently, there is no high-affinity and relatively specific inhibitor for the Kir6.2 pore. The importance of developing such inhibitors is twofold. First, in many cases, the lack of such an inhibitor precludes an unambiguous determination of the Kir6.2's role in certain physiological and pathological processes. This problem is exacerbated because Kir6.2 knockout mice do not yield the expected phenotypes of hyperinsulinemia and hypoglycemia, which in part, may reflect developmental adaptation. Second, mutations in Kir6.2 or SUR1 that increase the KATP current cause permanent neonatal diabetes mellitus (PNDM). Many patients who have PNDM have been successfully treated with sulphonylureas, a common class of antidiabetic drugs that bind to SUR1 and indirectly inhibit Kir6.2, thereby promoting insulin secretion. However, some PNDM-causing mutations render KATP channels insensitive to sulphonylureas. Conceptually, because these mutations are located intracellularly, an inhibitor blocking the Kir6.2 pore from the extracellular side might provide another approach to this problem. Here, by screening the venoms from >200 animals against human Kir6.2 coexpressed with SUR1, we discovered a small protein of 54 residues (SpTx-1) that inhibits the KATP channel from the extracellular side. It inhibits the channel with a dissociation constant value of 15 nM in a relatively specific manner and with an apparent one-to-one stoichiometry. SpTx-1 evidently inhibits the channel by primarily targeting Kir6.2 rather than SUR1; it inhibits not only wild-type Kir6.2 coexpressed with SUR1 but also a Kir6.2 mutant expressed without SUR1. Importantly, SpTx-1 suppresses both sulfonylurea-sensitive and -insensitive, PNDM-causing Kir6.2 mutants. Thus, it will be a valuable tool to investigate the channel's physiological and biophysical properties and to test a new strategy for treating sulfonylurea-resistant PNDM.


Subject(s)
Arthropod Venoms/pharmacology , Potassium Channel Blockers/pharmacology , Potassium Channels, Inwardly Rectifying/antagonists & inhibitors , Animals , Arthropod Venoms/chemistry , Arthropods , Binding Sites , Humans , Potassium Channel Blockers/chemistry , Potassium Channels, Inwardly Rectifying/chemistry , Potassium Channels, Inwardly Rectifying/metabolism , Protein Binding , Xenopus
19.
J Pain ; 19(10): 1157-1168, 2018 10.
Article in English | MEDLINE | ID: mdl-29758357

ABSTRACT

Chemotherapy-induced neuropathic pain is a common dose-limiting side effect of anticancerdrugs but lacks an effective treatment strategy. Scolopendra subspinipes has been used in traditional medicine to treat chronic neuronal diseases. Moreover, pharmacopuncture with S subspinipes (SSP) produces potent analgesia in humans and experimental animals. In this study, we examined the effect of SSP into the ST36 acupoint on oxaliplatin-induced mechanical allodynia in mice. Acupoint treatment with SSP (0.5%/20 µL) significantly decreased mechanical allodynia produced by a single oxaliplatin injection (10mg/kg i.p.), which was completely prevented by acupoint preinjection of lidocaine. Intrathecal treatment with yohimbine (25 µg/5 µL), an α2-adrenoceptor antagonist, prevented the anti-allodynic effect of SSP. In contrast, a high dose (0.1mg/kg i.p.) ofclonidine,an α2-adrenoceptor agonist, suppressed oxaliplatin-induced mechanical allodynia butproduced severe side effects including hypotension, bradycardia, and motor impairment. The combination of SSP with a lower dose of clonidine (0.03 mg/kg) produced a comparable analgesic effect without side effects. Collectively, our findings demonstrate that SSP produces an analgesic effect in oxaliplatin-induced pain via neuronal conduction at the acupoint and activation of spinal α2-adrenoceptors. Moreover, acombination of low-dose clonidine with SSP represents a novel and safe therapeutic strategy for chemotherapy-induced chronic pain. PERSPECTIVE: SSP can relieve oxaliplatin-induced mechanical allodynia. Moreover, SSP potentiates clonidine-induced anti-allodynia, allowing a lower dose of clonidine with no significant side effects. The combination of SSP and low-dose clonidine might provide a novel strategy for the management of chemotherapy-induced peripheral neuropathy.


Subject(s)
Arthropod Venoms/pharmacology , Hyperalgesia , Neuralgia , Acupuncture Points , Analgesics/pharmacology , Animals , Antineoplastic Agents/toxicity , Clonidine/pharmacology , Hyperalgesia/chemically induced , Hypotension , Male , Mice , Motor Disorders , Neuralgia/chemically induced , Neuralgia/prevention & control , Oxaliplatin/toxicity
20.
Toxicon ; 148: 172-196, 2018 Jun 15.
Article in English | MEDLINE | ID: mdl-29715467

ABSTRACT

Among venomous animals, Hymenoptera have been suggested as a rich source of natural toxins. Due to their broad ecological diversity, venom from Hymenoptera insects (bees, wasps and ants) have evolved differentially thus widening the types and biological functions of their components. To date, insect toxinology analysis have scarcely uncovered the complex composition of bee, wasp and ant venoms which include low molecular weight compounds, highly abundant peptides and proteins, including several allergens. In Hymenoptera, these complex mixtures of toxins represent a potent arsenal of biological weapons that are used for self-defense, to repel intruders and to capture prey. Consequently, Hymenoptera venom components have a broad range of pharmacological targets and have been extensively studied, as promising sources of new drugs and biopesticides. In addition, the identification and molecular characterization of Hymenoptera venom allergens have allowed for the rational design of component-resolved diagnosis of allergy, finally improving the outcome of venom immunotherapy (VIT). Until recently, a limited number of Hymenoptera venoms had been unveiled due to the technical limitations of the approaches used to date. Nevertheless, the application of novel techniques with high dynamic range has significantly increased the number of identified peptidic and proteinaceous toxins. Considering this, the present review summarizes the current knowledge about the most representative Hymenoptera venom peptides and proteins which are under study for a better understanding of the insect-caused envenoming process and the development of new drugs and biopesticides.


Subject(s)
Arthropod Venoms/chemistry , Arthropod Venoms/toxicity , Hymenoptera/chemistry , Animals , Arthropod Venoms/pharmacology , Insect Proteins/chemistry , Insect Proteins/pharmacology , Insect Proteins/toxicity , Peptides/chemistry , Peptides/pharmacology , Peptides/toxicity
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