Toxins

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5 pages, 222 KiB

Open AccessEditorial

Animal Venoms and Their Components: Molecular Mechanisms of Action

by Yuri Utkin

Toxins 2021, 13(6), 415; https://doi.org/10.3390/toxins13060415 - 11 Jun 2021

Cited by 3 | Viewed by 2945

Abstract

Animal venoms comprise numerous toxin families, consisting mainly of peptides and proteins [...] Full article

(This article belongs to the Special Issue Animal Venoms and Their Components: Molecular Mechanisms of Action)

Research

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19 pages, 3337 KiB

Open AccessArticle

Novel Three-Finger Neurotoxins from Naja melanoleuca Cobra Venom Interact with GABA_A and Nicotinic Acetylcholine Receptors

by Lina Son, Elena Kryukova, Rustam Ziganshin, Tatyana Andreeva, Denis Kudryavtsev, Igor Kasheverov, Victor Tsetlin and Yuri Utkin

Toxins 2021, 13(2), 164; https://doi.org/10.3390/toxins13020164 - 20 Feb 2021

Cited by 10 | Viewed by 3479

Abstract

Cobra venoms contain three-finger toxins (TFT) including α-neurotoxins efficiently binding nicotinic acetylcholine receptors (nAChRs). As shown recently, several TFTs block GABA_A receptors (GABA_ARs) with different efficacy, an important role of the TFTs central loop in binding to these receptors being [...] Read more.

Cobra venoms contain three-finger toxins (TFT) including α-neurotoxins efficiently binding nicotinic acetylcholine receptors (nAChRs). As shown recently, several TFTs block GABA_A receptors (GABA_ARs) with different efficacy, an important role of the TFTs central loop in binding to these receptors being demonstrated. We supposed that the positive charge (Arg36) in this loop of α-cobratoxin may explain its high affinity to GABA_AR and here studied α-neurotoxins from African cobra N. melanoleuca venom for their ability to interact with GABAARs and nAChRs. Three α-neurotoxins, close homologues of the known N. melanoleuca long neurotoxins 1 and 2, were isolated and sequenced. Their analysis on Torpedocalifornica and α7 nAChRs, as well as on acetylcholine binding proteins and on several subtypes of GABA_ARs, showed that all toxins interacted with the GABA_AR much weaker than with the nAChR: one neurotoxin was almost as active as α-cobratoxin, while others manifested lower activity. The earlier hypothesis about the essential role of Arg36 as the determinant of high affinity to GABA_AR was not confirmed, but the results obtained suggest that the toxin loop III may contribute to the efficient interaction of some long-chain neurotoxins with GABA_AR. One of isolated toxins manifested different affinity to two binding sites on Torpedo nAChR. Full article

(This article belongs to the Special Issue Animal Venoms and Their Components: Molecular Mechanisms of Action)

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21 pages, 6047 KiB

Open AccessArticle

ERK and mTORC1 Inhibitors Enhance the Anti-Cancer Capacity of the Octpep-1 Venom-Derived Peptide in Melanoma BRAF(V600E) Mutations

by Javier Moral-Sanz, Manuel A. Fernandez-Rojo, Jeremy Potriquet, Pamela Mukhopadhyay, Andreas Brust, Patrick Wilhelm, Taylor B. Smallwood, Richard J. Clark, Bryan G. Fry, Paul F. Alewood, Nicola Waddell, John J. Miles, Jason P. Mulvenna and Maria P. Ikonomopoulou

Toxins 2021, 13(2), 146; https://doi.org/10.3390/toxins13020146 - 14 Feb 2021

Cited by 7 | Viewed by 3564

Abstract

Melanoma is the main cause of skin cancer deaths, with special emphasis in those cases carrying BRAF mutations that trigger the mitogen-activated protein kinases (MAPK) signaling and unrestrained cell proliferation in the absence of mitogens. Current therapies targeting MAPK are hindered by drug [...] Read more.

Melanoma is the main cause of skin cancer deaths, with special emphasis in those cases carrying BRAF mutations that trigger the mitogen-activated protein kinases (MAPK) signaling and unrestrained cell proliferation in the absence of mitogens. Current therapies targeting MAPK are hindered by drug resistance and relapse that rely on metabolic rewiring and Akt activation. To identify new drug candidates against melanoma, we investigated the molecular mechanism of action of the Octopus Kaurna-derived peptide, Octpep-1, in human BRAF(V600E) melanoma cells using proteomics and RNAseq coupled with metabolic analysis. Fluorescence microscopy verified that Octpep-1 tagged with fluorescein enters MM96L and NFF cells and distributes preferentially in the perinuclear area of MM96L cells. Proteomics and RNAseq revealed that Octpep-1 targets PI3K/AKT/mTOR signaling in MM96L cells. In addition, Octpep-1 combined with rapamycin (mTORC1 inhibitor) or LY3214996 (ERK1/2 inhibitor) augmented the cytotoxicity against BRAF(V600E) melanoma cells in comparison with the inhibitors or Octpep-1 alone. Octpep-1-treated MM96L cells displayed reduced glycolysis and mitochondrial respiration when combined with LY3214996. Altogether these data support Octpep-1 as an optimal candidate in combination therapies for melanoma BRAF(V600E) mutations. Full article

(This article belongs to the Special Issue Animal Venoms and Their Components: Molecular Mechanisms of Action)

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16 pages, 12154 KiB

Open AccessArticle

Electric Blue: Molecular Evolution of Three-Finger Toxins in the Long-Glanded Coral Snake Species Calliophis bivirgatus

by Daniel Dashevsky, Darin Rokyta, Nathaniel Frank, Amanda Nouwens and Bryan G. Fry

Toxins 2021, 13(2), 124; https://doi.org/10.3390/toxins13020124 - 8 Feb 2021

Cited by 14 | Viewed by 4980

Abstract

The genus Calliophis is the most basal branch of the family Elapidae and several species in it have developed highly elongated venom glands. Recent research has shown that C. bivirgatus has evolved a seemingly unique toxin (calliotoxin) that produces spastic paralysis in their [...] Read more.

The genus Calliophis is the most basal branch of the family Elapidae and several species in it have developed highly elongated venom glands. Recent research has shown that C. bivirgatus has evolved a seemingly unique toxin (calliotoxin) that produces spastic paralysis in their prey by acting on the voltage-gated sodium (Na_V) channels. We assembled a transcriptome from C. bivirgatus to investigate the molecular characteristics of these toxins and the venom as a whole. We find strong confirmation that this genus produces the classic elapid eight-cysteine three-finger toxins, that δ

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-elapitoxins (toxins that resemble calliotoxin) are responsible for a substantial portion of the venom composition, and that these toxins form a distinct clade within a larger, more diverse clade of C. bivirgatus three-finger toxins. This broader clade of C. bivirgatus toxins also contains the previously named maticotoxins and is somewhat closely related to cytotoxins from other elapids. However, the toxins from this clade that have been characterized are not themselves cytotoxic. No other toxins show clear relationships to toxins of known function from other species. Full article

(This article belongs to the Special Issue Animal Venoms and Their Components: Molecular Mechanisms of Action)

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15 pages, 4300 KiB

Open AccessArticle

BmK NSPK, a Potent Potassium Channel Inhibitor from Scorpion Buthus martensii Karsch, Promotes Neurite Outgrowth via NGF/TrkA Signaling Pathway

by Fang Zhao, Xiaohan Zou, Shaoheng Li, Jing He, Chuchu Xi, Qinglian Tang, Yujing Wang and Zhengyu Cao

Toxins 2021, 13(1), 33; https://doi.org/10.3390/toxins13010033 - 5 Jan 2021

Cited by 4 | Viewed by 3109

Abstract

Scorpion toxins represent a variety of tools to explore molecular mechanisms and cellular signaling pathways of many biological functions. These toxins are also promising lead compounds for developing treatments for many neurological diseases. In the current study, we purified a new scorpion toxin [...] Read more.

Scorpion toxins represent a variety of tools to explore molecular mechanisms and cellular signaling pathways of many biological functions. These toxins are also promising lead compounds for developing treatments for many neurological diseases. In the current study, we purified a new scorpion toxin designated as BmK NSPK (Buthus martensii Karsch neurite-stimulating peptide targeting K_v channels) from the BmK venom. The primary structure was determined using Edman degradation. BmK NSPK directly inhibited outward K⁺ current without affecting sodium channel activities, depolarized membrane, and increased spontaneous calcium oscillation in spinal cord neurons (SCNs) at low nanomolar concentrations. BmK NSPK produced a nonmonotonic increase on the neurite extension that peaked at ~10 nM. Mechanistic studies demonstrated that BmK NSPK increased the release of nerve growth factor (NGF). The tyrosine kinases A (TrkA) receptor inhibitor, GW 441756, eliminated the BmK NSPK-induced neurite outgrowth. BmK NSPK also increased phosphorylation levels of protein kinase B (Akt) that is the downstream regulator of TrkA receptors. These data demonstrate that BmK NSPK is a new voltage-gated potassium (K_v) channel inhibitor that augments neurite extension via NGF/TrkA signaling pathway. K_v channels may represent molecular targets to modulate SCN development and regeneration and to develop the treatments for spinal cord injury. Full article

(This article belongs to the Special Issue Animal Venoms and Their Components: Molecular Mechanisms of Action)

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14 pages, 5541 KiB

Open AccessArticle

Toxicological Characterization and Phospholipase D Activity of the Venom of the Spider Sicarius thomisoides

by Tomás Arán-Sekul, Ivanka Perčić-Sarmiento, Verónica Valencia, Nelly Olivero, José M. Rojas, Jorge E. Araya, Andrés Taucare-Ríos and Alejandro Catalán

Toxins 2020, 12(11), 702; https://doi.org/10.3390/toxins12110702 - 6 Nov 2020

Cited by 7 | Viewed by 8621

Abstract

Envenomation by Loxosceles spiders (Sicariidae family) has been thoroughly documented. However, little is known about the potential toxicity of members from the Sicarius genus. Only the venom of the Brazilian Sicarius ornatus spider has been toxicologically characterized. In Chile, the Sicarius thomisoides [...] Read more.

Envenomation by Loxosceles spiders (Sicariidae family) has been thoroughly documented. However, little is known about the potential toxicity of members from the Sicarius genus. Only the venom of the Brazilian Sicarius ornatus spider has been toxicologically characterized. In Chile, the Sicarius thomisoides species is widely distributed in desert and semidesert environments, and it is not considered a dangerous spider for humans. This study aimed to characterize the potential toxicity of the Chilean S. thomisoides spider. To do so, specimens of S. thomisoides were captured in the Atacama Desert, the venom was extracted, and the protein concentration was determined. Additionally, the venoms were analyzed by electrophoresis and Western blotting using anti-recombinant L. laeta PLD1 serum. Phospholipase D enzymatic activity was assessed, and the hemolytic and cytotoxic effects were evaluated and compared with those of the L. laeta venom. The S. thomisoides venom was able to hydrolyze sphingomyelin as well as induce complement-dependent hemolysis and the loss of viability of skin fibroblasts with a dermonecrotic effect of the venom in rabbits. The venom of S. thomisoides showed intraspecific variations, with a similar protein pattern as that of L. laeta venom at 32–35 kDa, recognized by serum anti-LlPLD1. In this context, we can conclude that the venom of Sicarius thomisoides is similar to Loxosceles laeta in many aspects, and the dermonecrotic toxin present in their venom could cause severe harm to humans; thus, precautions are necessary to avoid exposure to their bite. Full article

(This article belongs to the Special Issue Animal Venoms and Their Components: Molecular Mechanisms of Action)

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14 pages, 2241 KiB

Open AccessArticle

The Insecticidal Activity of Rhinella schneideri (Werner, 1894) Paratoid Secretion in Nauphoeta cinerea Cocroaches

by Allan Leal, Etiely Karnopp, Yuri Correia Barreto, Raquel Soares Oliveira, Maria Eduarda Rosa, Bruna Trindade Borges, Flávia Luana Goulart, Velci Queiróz de Souza, Manuela Merlin Laikowski, Sidnei Moura, Lúcia Vinadé, João Batista Teixeira da Rocha and Cháriston André Dal Belo

Toxins 2020, 12(10), 630; https://doi.org/10.3390/toxins12100630 - 1 Oct 2020

Cited by 10 | Viewed by 3335

Abstract

Rhinella schneideri is a common toad found in South America, whose paratoid toxic secretion has never been explored as an insecticide. In order to evaluate its insecticidal potential, Nauphoeta cinerea cockroaches were used as an experimental model in biochemical, physiological and behavioral procedures. [...] Read more.

Rhinella schneideri is a common toad found in South America, whose paratoid toxic secretion has never been explored as an insecticide. In order to evaluate its insecticidal potential, Nauphoeta cinerea cockroaches were used as an experimental model in biochemical, physiological and behavioral procedures. Lethality assays with Rhinella schneideri paratoid secretion (RSPS) determined the LD₅₀ value after 24 h (58.07µg/g) and 48 h exposure (44.07 µg/g) (R² = 0.882 and 0.954, respectively). Acetylcholinesterase activity (AChE) after RSPS at its highest dose promoted an enzyme inhibition of 40%, a similar effect observed with neostigmine administration (p < 0.001, n= 5). Insect locomotion recordings revealed that RSPS decreased the distance traveled by up to 37% with a concomitant 85% increase in immobile episodes (p < 0.001, n = 36). RSPS added to in vivo cockroach semi-isolated heart preparation promoted an irreversible and dose dependent decrease in heart rate, showing a complete failure after 30 min recording (p < 0.001, n ≥ 6). In addition, RSPS into nerve-muscle preparations induced a dose-dependent neuromuscular blockade, reaching a total blockage at 70 min at the highest dose applied (p < 0.001, n ≥ 6). The effect of RSPS on spontaneous sensorial action potentials was characterized by an increase in the number of spikes 61% (p < 0.01). Meanwhile, there was 42% decrease in the mean area of those potentials (p < 0.05, n ≥ 6). The results obtained here highlight the potential insecticidal relevance of RSPS and its potential biotechnological application. Full article

(This article belongs to the Special Issue Animal Venoms and Their Components: Molecular Mechanisms of Action)

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25 pages, 4591 KiB

Open AccessArticle

The Parotoid Gland Secretion from Peruvian Toad Rhinella horribilis (Wiegmann, 1833): Chemical Composition and Effect on the Proliferation and Migration of Lung Cancer Cells

by Guillermo Schmeda-Hirschmann, Jean Paulo de Andrade, Marilú Roxana Soto-Vasquez, Paul Alan Arkin Alvarado-García, Charlotte Palominos, Sebastián Fuentes-Retamal, Mathias Mellado, Pablo Correa and Félix A. Urra

Toxins 2020, 12(9), 608; https://doi.org/10.3390/toxins12090608 - 22 Sep 2020

Cited by 10 | Viewed by 4960

Abstract

Since Rhinella sp. toads produce bioactive substances, some species have been used in traditional medicine and magical practices by ancient cultures in Peru. During several decades, the Rhinella horribilis toad was confused with the invasive toad Rhinella marina, a species documented with [...] Read more.

Since Rhinella sp. toads produce bioactive substances, some species have been used in traditional medicine and magical practices by ancient cultures in Peru. During several decades, the Rhinella horribilis toad was confused with the invasive toad Rhinella marina, a species documented with extensive toxinological studies. In contrast, the chemical composition and biological effects of the parotoid gland secretions (PGS) remain still unknown for R. horribilis. In this work, we determine for the first time 55 compounds from the PGS of R. horribilis, which were identified using HPLC-MS/MS. The crude extract inhibited the proliferation of A549 cancer cells with IC₅₀ values of 0.031 ± 0.007 and 0.015 ± 0.001 µg/mL at 24 and 48 h of exposure, respectively. Moreover, it inhibited the clonogenic capacity, increased ROS levels, and prevented the etoposide-induced apoptosis, suggesting that the effect of R. horribilis poison secretion was by cell cycle blocking before of G2/M-phase checkpoint. Fraction B was the most active and strongly inhibited cancer cell migration. Our results indicate that the PGS of R. horribilis are composed of alkaloids, bufadienolides, and argininyl diacids derivatives, inhibiting the proliferation and migration of A549 cells. Full article

(This article belongs to the Special Issue Animal Venoms and Their Components: Molecular Mechanisms of Action)

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23 pages, 15261 KiB

Open AccessArticle

An Investigation of Three-Finger Toxin—nAChR Interactions through Rosetta Protein Docking

by Alican Gulsevin and Jens Meiler

Toxins 2020, 12(9), 598; https://doi.org/10.3390/toxins12090598 - 16 Sep 2020

Cited by 8 | Viewed by 5216

Abstract

Three-finger toxins (3FTX) are a group of peptides that affect multiple receptor types. One group of proteins affected by 3FTX are nicotinic acetylcholine receptors (nAChR). Structural information on how neurotoxins interact with nAChR is limited and is confined to a small group of [...] Read more.

Three-finger toxins (3FTX) are a group of peptides that affect multiple receptor types. One group of proteins affected by 3FTX are nicotinic acetylcholine receptors (nAChR). Structural information on how neurotoxins interact with nAChR is limited and is confined to a small group of neurotoxins. Therefore, in silico methods are valuable in understanding the interactions between 3FTX and different nAChR subtypes, but there are no established protocols to model 3FTX–nAChR interactions. We followed a homology modeling and protein docking protocol to address this issue and tested its success on three different systems. First, neurotoxin peptides co-crystallized with acetylcholine binding protein (AChBP) were re-docked to assess whether Rosetta protein–protein docking can reproduce the native poses. Second, experimental data on peptide binding to AChBP was used to test whether the docking protocol can qualitatively distinguish AChBP-binders from non-binders. Finally, we docked eight peptides with known α7 and muscle-type nAChR binding properties to test whether the protocol can explain the differential activities of the peptides at the two receptor subtypes. Overall, the docking protocol predicted the qualitative and some specific aspects of 3FTX binding to nAChR with reasonable success and shed light on unknown aspects of 3FTX binding to different receptor subtypes. Full article

(This article belongs to the Special Issue Animal Venoms and Their Components: Molecular Mechanisms of Action)

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12 pages, 2774 KiB

Open AccessArticle

Two Novel Peptide Toxins from the Spider Cyriopagopus longipes Inhibit Tetrodotoxin-Sensitive Sodium Channels

by Qingfeng Zhang, Yuxin Si, Li Yang, Li Wang, Shuijiao Peng, Yiming Chen, Minzhi Chen, Xi Zhou and Zhonghua Liu

Toxins 2020, 12(9), 529; https://doi.org/10.3390/toxins12090529 - 19 Aug 2020

Cited by 6 | Viewed by 3834

Abstract

Sodium channels play a critical role in the generation and propagation of action potentials in excitable tissues, such as nerves, cardiac muscle, and skeletal muscle, and are the primary targets of toxins found in animal venoms. Here, two novel peptide toxins (Cl6a and [...] Read more.

Sodium channels play a critical role in the generation and propagation of action potentials in excitable tissues, such as nerves, cardiac muscle, and skeletal muscle, and are the primary targets of toxins found in animal venoms. Here, two novel peptide toxins (Cl6a and Cl6b) were isolated from the venom of the spider Cyriopagopus longipes and characterized. Cl6a and Cl6b were shown to be inhibitors of tetrodotoxin-sensitive (TTX-S), but not TTX-resistant, sodium channels. Among the TTX-S channels investigated, Cl6a and Cl6b showed the highest degree of inhibition against NaV1.7 (half-maximal inhibitory concentration (IC₅₀) of 11.0 ± 2.5 nM and 18.8 ± 2.4 nM, respectively) in an irreversible manner that does not alter channel activation, inactivation, or repriming kinetics. Moreover, analysis of NaV1.7/NaV1.8 chimeric channels revealed that Cl6b is a site 4 neurotoxin. Site-directed mutagenesis analysis indicated that D816, V817, and E818 observably affected the efficacy of the Cl6b-NaV1.7 interaction, suggesting that these residues might directly affect the interaction of NaV1.7 with Cl6b. Taken together, these two novel peptide toxins act as potent and sustained NaV1.7 blockers and may have potential in the pharmacological study of sodium channels. Full article

(This article belongs to the Special Issue Animal Venoms and Their Components: Molecular Mechanisms of Action)

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17 pages, 2829 KiB

Open AccessArticle

Improved Antithrombotic Activity and Diminished Bleeding Side Effect of a PEGylated α_IIbβ₃ Antagonist, Disintegrin

by Yu-Ju Kuo, Yao Tsung Chang, Ching-Hu Chung, Woei-Jer Chuang and Tur-Fu Huang

Toxins 2020, 12(7), 426; https://doi.org/10.3390/toxins12070426 - 28 Jun 2020

Cited by 9 | Viewed by 2798

Abstract

Polymer polyethylene glycol (PEG), or PEGylation of polypeptides improves protein drug stability by decreasing degradation and reducing renal clearance. To produce a pharmaceutical disintegrin derivative, the N-terminal PEGylation technique was used to modify the disintegrin derivative [KGDRR]trimucrin for favorable safety, pharmacokinetic profiles, and [...] Read more.

Polymer polyethylene glycol (PEG), or PEGylation of polypeptides improves protein drug stability by decreasing degradation and reducing renal clearance. To produce a pharmaceutical disintegrin derivative, the N-terminal PEGylation technique was used to modify the disintegrin derivative [KGDRR]trimucrin for favorable safety, pharmacokinetic profiles, and antithrombotic efficacy. We compared intact [KGDRR]trimucrin (RR) and PEGylated KGDRR (PEG-RR) by in vitro and in vivo systems for their antithrombotic activities. The activity of platelet aggregation inhibition and the bleeding tendency side effect were also investigated. PEG-RR exhibited optimal potency in inhibiting platelet aggregation of human/mouse platelet-rich plasma activated by collagen or ADP with a lower IC₅₀ than the intact derivative RR. In the illumination-induced mesenteric venous thrombosis model, RR and PEG-RR efficaciously prevented occlusive thrombosis in a dose-dependent manner. In rotational thromboelastometry assay, PEG-RR did not induce hypocoagulation in human whole blood even given at a higher concentration (30 μg/mL), while RR slightly prolonged clotting time. However, RR and PEG-RR were not associated with severe thrombocytopenia or bleeding in FcγRIIa-transgenic mice at equally efficacious antithrombotic dosages. We also found the in vivo half-life of PEGylation was longer than RR (RR: 15.65 h vs. PEG-RR: 20.45 h). In conclusion, injectable PEG-RR with prolonged half-life and decreased bleeding risk is a safer anti-thrombotic agent for long-acting treatment of thrombus diseases. Full article

(This article belongs to the Special Issue Animal Venoms and Their Components: Molecular Mechanisms of Action)

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26 pages, 10171 KiB

Open AccessArticle

Molecular Mechanism by Which Cobra Venom Cardiotoxins Interact with the Outer Mitochondrial Membrane

by Feng Li, Indira H. Shrivastava, Paul Hanlon, Ruben K. Dagda and Edward S. Gasanoff

Toxins 2020, 12(7), 425; https://doi.org/10.3390/toxins12070425 - 27 Jun 2020

Cited by 20 | Viewed by 3332

Abstract

Cardiotoxin CTII from Naja oxiana cobra venom translocates to the intermembrane space (IMS) of mitochondria to disrupt the structure and function of the inner mitochondrial membrane. At low concentrations, CTII facilitates ATP-synthase activity, presumably via the formation of non-bilayer, immobilized phospholipids that are [...] Read more.

Cardiotoxin CTII from Naja oxiana cobra venom translocates to the intermembrane space (IMS) of mitochondria to disrupt the structure and function of the inner mitochondrial membrane. At low concentrations, CTII facilitates ATP-synthase activity, presumably via the formation of non-bilayer, immobilized phospholipids that are critical in modulating ATP-synthase activity. In this study, we investigated the effects of another cardiotoxin CTI from Naja oxiana cobra venom on the structure of mitochondrial membranes and on mitochondrial-derived ATP synthesis. By employing robust biophysical methods including ³¹P-NMR and ¹H-NMR spectroscopy, we analyzed the effects of CTI and CTII on phospholipid packing and dynamics in model phosphatidylcholine (PC) membranes enriched with 2.5 and 5.0 mol% of cardiolipin (CL), a phospholipid composition that mimics that in the outer mitochondrial membrane (OMM). These experiments revealed that CTII converted a higher percentage of bilayer phospholipids to a non-bilayer and immobilized state and both cardiotoxins utilized CL and PC molecules to form non-bilayer structures. Furthermore, in order to gain further understanding on how cardiotoxins bind to mitochondrial membranes, we employed molecular dynamics (MD) and molecular docking simulations to investigate the molecular mechanisms by which CTII and CTI interactively bind with an in silico phospholipid membrane that models the composition similar to the OMM. In brief, MD studies suggest that CTII utilized the N-terminal region to embed the phospholipid bilayer more avidly in a horizontal orientation with respect to the lipid bilayer and thereby penetrate at a faster rate compared with CTI. Molecular dynamics along with the Autodock studies identified critical amino acid residues on the molecular surfaces of CTII and CTI that facilitated the long-range and short-range interactions of cardiotoxins with CL and PC. Based on our compiled data and our published findings, we provide a conceptual model that explains a molecular mechanism by which snake venom cardiotoxins, including CTI and CTII, interact with mitochondrial membranes to alter the mitochondrial membrane structure to either upregulate ATP-synthase activity or disrupt mitochondrial function. Full article

(This article belongs to the Special Issue Animal Venoms and Their Components: Molecular Mechanisms of Action)

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21 pages, 2828 KiB

Open AccessArticle

Chemical and Pharmacological Screening of Rhinella icterica (Spix 1824) Toad Parotoid Secretion in Avian Preparations

by Raquel Soares Oliveira, Bruna Trindade Borges, Allan Pinto Leal, Manuela Merlin Lailowski, Karla de Castro Figueiredo Bordon, Velci Queiróz de Souza, Lúcia Vinadé, Tiago Gomes dos Santos, Stephen Hyslop, Sidnei Moura, Eliane Candiani Arantes, Alexandre Pinto Corrado and Cháriston A. Dal Belo

Toxins 2020, 12(6), 396; https://doi.org/10.3390/toxins12060396 - 15 Jun 2020

Cited by 8 | Viewed by 3688

Abstract

The biological activity of Rhinella icterica parotoid secretion (RIPS) and some of its chromatographic fractions (RI18, RI19, RI23, and RI24) was evaluated in the current study. Mass spectrometry of these fractions indicated the presence of sarmentogenin, argentinogenin, (5β,12β)-12,14-dihydroxy-11-oxobufa-3,20,22-trienolide, marinobufagin, [...] Read more.

The biological activity of Rhinella icterica parotoid secretion (RIPS) and some of its chromatographic fractions (RI18, RI19, RI23, and RI24) was evaluated in the current study. Mass spectrometry of these fractions indicated the presence of sarmentogenin, argentinogenin, (5β,12β)-12,14-dihydroxy-11-oxobufa-3,20,22-trienolide, marinobufagin, bufogenin B, 11α,19-dihydroxy-telocinobufagin, bufotalin, monohydroxylbufotalin, 19-oxo-cinobufagin, 3α,12β,25,26-tetrahydroxy-7-oxo-5β-cholestane-26-O-sulfate, and cinobufagin-3-hemisuberate that were identified as alkaloid and steroid compounds, in addition to marinoic acid and N-methyl-5-hydroxy-tryptamine. In chick brain slices, all fractions caused a slight decrease in cell viability, as also seen with the highest concentration of RIPS tested. In chick biventer cervicis neuromuscular preparations, RIPS and all four fractions significantly inhibited junctional acetylcholinesterase (AChE) activity. In this preparation, only fraction RI23 completely mimicked the pharmacological profile of RIPS, which included a transient facilitation in the amplitude of muscle twitches followed by progressive and complete neuromuscular blockade. Mass spectrometric analysis showed that RI23 consisted predominantly of bufogenins, a class of steroidal compounds known for their cardiotonic activity mediated by a digoxin- or ouabain-like action and the blockade of voltage-dependent L-type calcium channels. These findings indicate that the pharmacological activities of RI23 (and RIPS) are probably mediated by: (1) inhibition of AChE activity that increases the junctional content of Ach; (2) inhibition of neuronal Na⁺/K⁺-ATPase, leading to facilitation followed by neuromuscular blockade; and (3) blockade of voltage-dependent Ca²⁺ channels, leading to stabilization of the motor endplate membrane. Full article

(This article belongs to the Special Issue Animal Venoms and Their Components: Molecular Mechanisms of Action)

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12 pages, 4915 KiB

Open AccessArticle

Screening Snake Venoms for Toxicity to Tetrahymena Pyriformis Revealed Anti-Protozoan Activity of Cobra Cytotoxins

by Olga N. Kuleshina, Elena V. Kruykova, Elena G. Cheremnykh, Leonid V. Kozlov, Tatyana V. Andreeva, Vladislav G. Starkov, Alexey V. Osipov, Rustam H. Ziganshin, Victor I. Tsetlin and Yuri N. Utkin

Toxins 2020, 12(5), 325; https://doi.org/10.3390/toxins12050325 - 15 May 2020

Cited by 9 | Viewed by 4703

Abstract

Snake venoms possess lethal activities against different organisms, ranging from bacteria to higher vertebrates. Several venoms were shown to be active against protozoa, however, data about the anti-protozoan activity of cobra and viper venoms are very scarce. We tested the effects of venoms [...] Read more.

Snake venoms possess lethal activities against different organisms, ranging from bacteria to higher vertebrates. Several venoms were shown to be active against protozoa, however, data about the anti-protozoan activity of cobra and viper venoms are very scarce. We tested the effects of venoms from several snake species on the ciliate Tetrahymena pyriformis. The venoms tested induced T. pyriformis immobilization, followed by death, the most pronounced effect being observed for cobra Naja sumatrana venom. The active polypeptides were isolated from this venom by a combination of gel-filtration, ion exchange and reversed-phase HPLC and analyzed by mass spectrometry. It was found that these were cytotoxins of the three-finger toxin family. The cytotoxins from several cobra species were tested and manifested toxicity for infusorians. Light microscopy revealed that, because of the cytotoxin action, the infusorians’ morphology was changed greatly, from teardrop-like to an almost spherical shape, this alteration being accompanied by a leakage of cell contents. Fluorescence microscopy showed that the fluorescently labelled cytotoxin 2 from cobra N. oxiana was localized mainly at the membrane of killed infusorians, indicating that cytotoxins may kill T. pyriformis by causing membrane rupture. This work is the first evidence of the antiprotozoal activity of cobra venom cytotoxins, as demonstrated by the example of the ciliate T. pyriformis. Full article

(This article belongs to the Special Issue Animal Venoms and Their Components: Molecular Mechanisms of Action)

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17 pages, 4306 KiB

Open AccessArticle

Neurotoxin Merging: A Strategy Deployed by the Venom of the Spider Cupiennius salei to Potentiate Toxicity on Insects

by Benjamin Clémençon, Lucia Kuhn-Nentwig, Nicolas Langenegger, Lukas Kopp, Steve Peigneur, Jan Tytgat, Wolfgang Nentwig and Benjamin P. Lüscher

Toxins 2020, 12(4), 250; https://doi.org/10.3390/toxins12040250 - 12 Apr 2020

Cited by 13 | Viewed by 4572

Abstract

The venom of Cupiennius salei is composed of dozens of neurotoxins, with most of them supposed to act on ion channels. Some insecticidal monomeric neurotoxins contain an α-helical part besides their inhibitor cystine knot (ICK) motif (type 1). Other neurotoxins have, besides the [...] Read more.

The venom of Cupiennius salei is composed of dozens of neurotoxins, with most of them supposed to act on ion channels. Some insecticidal monomeric neurotoxins contain an α-helical part besides their inhibitor cystine knot (ICK) motif (type 1). Other neurotoxins have, besides the ICK motif, an α-helical part of an open loop, resulting in a heterodimeric structure (type 2). Due to their low toxicity, it is difficult to understand the existence of type 2 peptides. Here, we show with the voltage clamp technique in oocytes of Xenopus laevis that a combined application of structural type 1 and type 2 neurotoxins has a much more pronounced cytolytic effect than each of the toxins alone. In biotests with Drosophila melanogaster, the combined effect of both neurotoxins was enhanced by 2 to 3 log units when compared to the components alone. Electrophysiological measurements of a type 2 peptide at 18 ion channel types, expressed in Xenopus laevis oocytes, showed no effect. Microscale thermophoresis data indicate a monomeric/heterodimeric peptide complex formation, thus a direct interaction between type 1 and type 2 peptides, leading to cell death. In conclusion, peptide mergers between both neurotoxins are the main cause for the high cytolytic activity of Cupiennius salei venom. Full article

(This article belongs to the Special Issue Animal Venoms and Their Components: Molecular Mechanisms of Action)

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9 pages, 1526 KiB

Open AccessCommunication

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

by Mouzarllem B. Reis, Jefferson Elias-Oliveira, Marcella R. Pastore, Simone G. Ramos, Luiz G. Gardinassi and Lúcia H. Faccioli

Toxins 2020, 12(3), 163; https://doi.org/10.3390/toxins12030163 - 5 Mar 2020

Cited by 6 | Viewed by 3280

Abstract

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. [...] Read more.

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. Full article

(This article belongs to the Special Issue Animal Venoms and Their Components: Molecular Mechanisms of Action)

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10 pages, 2002 KiB

Open AccessArticle

Snake C-Type Lectins Potentially Contribute to the Prey Immobilization in Protobothrops mucrosquamatus and Trimeresurus stejnegeri Venoms

by Huiwen Tian, Ming Liu, Jiameng Li, Runjia Xu, Chengbo Long, Hao Li, James Mwangi, Qiumin Lu, Ren Lai and Chuanbin Shen

Toxins 2020, 12(2), 105; https://doi.org/10.3390/toxins12020105 - 6 Feb 2020

Cited by 13 | Viewed by 3497

Abstract

Snake venoms contain components selected to immobilize prey. The venoms from Elapidae mainly contain neurotoxins, which are critical for rapid prey paralysis, while the venoms from Viperidae and Colubridae may contain fewer neurotoxins but are likely to induce circulatory disorders. Here, we show [...] Read more.

Snake venoms contain components selected to immobilize prey. The venoms from Elapidae mainly contain neurotoxins, which are critical for rapid prey paralysis, while the venoms from Viperidae and Colubridae may contain fewer neurotoxins but are likely to induce circulatory disorders. Here, we show that the venoms from Protobothrops mucrosquamatus and Trimeresurus stejnegeri are comparable to those of Naja atra in prey immobilization. Further studies indicate that snake C-type lectin-like proteins (snaclecs), which are one of the main nonenzymatic components in viper venoms, are responsible for rapid prey immobilization. Snaclecs (mucetin and stejnulxin) from the venoms of P. mucrosquamatus and T. stejnegeri induce the aggregation of both mammalian platelets and avian thrombocytes, leading to acute cerebral ischemia, and reduced animal locomotor activity and exploration in the open field test. Viper venoms in the absence of snaclecs fail to aggregate platelets and thrombocytes, and thus show an attenuated ability to cause cerebral ischemia and immobilization of their prey. This work provides novel insights into the prey immobilization mechanism of Viperidae snakes and the understanding of viper envenomation-induced cerebral infarction. Full article

(This article belongs to the Special Issue Animal Venoms and Their Components: Molecular Mechanisms of Action)

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14 pages, 4744 KiB

Open AccessArticle

Bv8-Like Toxin from the Frog Venom of Amolops jingdongensis Promotes Wound Healing via the Interleukin-1 Signaling Pathway

by Jiajia Chang, Xiaoqin He, Jingmei Hu, Peter Muiruri Kamau, Ren Lai, Dingqi Rao and Lei Luo

Toxins 2020, 12(1), 15; https://doi.org/10.3390/toxins12010015 - 29 Dec 2019

Cited by 11 | Viewed by 4313

Abstract

Prokineticins are highly conserved small peptides family expressed in all vertebrates, which contain a wide spectrum of functions. In this study, a prokineticin homolog (Bv8-AJ) isolated from the venom of frog Amolops jingdongensis was fully characterized. Bv8-AJ accelerated full-thickness wounds healing of mice [...] Read more.

Prokineticins are highly conserved small peptides family expressed in all vertebrates, which contain a wide spectrum of functions. In this study, a prokineticin homolog (Bv8-AJ) isolated from the venom of frog Amolops jingdongensis was fully characterized. Bv8-AJ accelerated full-thickness wounds healing of mice model by promoting the initiation and the termination of inflammatory phase. Moreover, Bv8-AJ exerted strong proliferative effect on fibroblasts and keratinocytes isolated from newborn mice by activating interleukin (IL)-1 production. Our findings indicate that Bv8 is a potent wound healing regulator and may reveal the mechanism of rapid wound-healing in amphibian skins. Full article

(This article belongs to the Special Issue Animal Venoms and Their Components: Molecular Mechanisms of Action)

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13 pages, 2415 KiB

Open AccessArticle

Identification and Characterization of ShSPI, a Kazal-Type Elastase Inhibitor from the Venom of Scolopendra Hainanum

by Ning Luan, Qiyu Zhao, Zilei Duan, Mengyao Ji, Meichen Xing, Tengyu Zhu, James Mwangi, Mingqiang Rong, Jiangxin Liu and Ren Lai

Toxins 2019, 11(12), 708; https://doi.org/10.3390/toxins11120708 - 5 Dec 2019

Cited by 8 | Viewed by 3519

Abstract

Elastase is a globular glycoprotein and belongs to the chymotrypsin family. It is involved in several inflammatory cascades on the basis of cleaving the important connective tissue protein elastin, and is strictly regulated to a balance by several endogenous inhibitors. When elastase and [...] Read more.

Elastase is a globular glycoprotein and belongs to the chymotrypsin family. It is involved in several inflammatory cascades on the basis of cleaving the important connective tissue protein elastin, and is strictly regulated to a balance by several endogenous inhibitors. When elastase and its inhibitors are out of balance, severe diseases will develop, especially those involved in the cardiopulmonary system. Much attention has been attracted in seeking innovative elastase inhibitors and various advancements have been taken on clinical trials of these inhibitors. Natural functional peptides from venomous animals have been shown to have anti-protease properties. Here, we identified a kazal-type serine protease inhibitor named ShSPI from the cDNA library of the venom glands of Scolopendra hainanum. ShSPI showed significant inhibitory effects on porcine pancreatic elastase and human neutrophils elastase with Ki values of 225.83 ± 20 nM and 12.61 ± 2 nM, respectively. Together, our results suggest that ShSPI may be an excellent candidate to develop a drug for cardiopulmonary diseases. Full article

(This article belongs to the Special Issue Animal Venoms and Their Components: Molecular Mechanisms of Action)

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11 pages, 1462 KiB

Open AccessEditor’s ChoiceArticle

The Latoia consocia Caterpillar Induces Pain by Targeting Nociceptive Ion Channel TRPV1

by Zhihao Yao, Peter Muiruri Kamau, Yalan Han, Jingmei Hu, Anna Luo, Lei Luo, Jie Zheng, Yuhua Tian and Ren Lai

Toxins 2019, 11(12), 695; https://doi.org/10.3390/toxins11120695 - 27 Nov 2019

Cited by 12 | Viewed by 4646

Abstract

Accidental contact with caterpillar bristles causes local symptoms such as severe pain, intense heat, edema, erythema, and pruritus. However, there is little functional evidence to indicate a potential mechanism. In this study, we analyzed the biological characteristics of the crude venom from the [...] Read more.

Accidental contact with caterpillar bristles causes local symptoms such as severe pain, intense heat, edema, erythema, and pruritus. However, there is little functional evidence to indicate a potential mechanism. In this study, we analyzed the biological characteristics of the crude venom from the larval stage of Latoia consocia living in South-West China. Intraplantar injection of the venom into the hind paws of mice induced severe acute pain behaviors in wild type (WT) mice; the responses were much reduced in TRPV1-deficit (TRPV1 KO) mice. The TRPV1-specific inhibitor, capsazepine, significantly attenuated the pain behaviors. Furthermore, the crude venom evoked strong calcium signals in the dorsal root ganglion (DRG) neurons of WT mice but not those of TRPV1 KO mice. Among the pain-related ion channels we tested, the crude venom only activated the TRPV1 channel. To better understand the venom components, we analyzed the transcriptome of the L. consocia sebaceous gland region. Our study suggests that TRPV1 serves as a primary nociceptor in caterpillar-induced pain and forms the foundation for elucidating the pain-producing mechanism. Full article

(This article belongs to the Special Issue Animal Venoms and Their Components: Molecular Mechanisms of Action)

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18 pages, 3761 KiB

Open AccessArticle

Cloning and Immunosuppressive Properties of an Acyl-Activating Enzyme from the Venom Apparatus of Tetrastichus brontispae (Hymenoptera: Eulophidae)

by Xiao-Mei Zhang, Hua-Jian Zhang, Min Liu, Bin Liu, Xia-Fang Zhang, Cheng-Jun Ma, Ting-Ting Fu, You-Ming Hou and Bao-Zhen Tang

Toxins 2019, 11(11), 672; https://doi.org/10.3390/toxins11110672 - 18 Nov 2019

Cited by 7 | Viewed by 3225

Abstract

Venom injected into the host plays vital roles in facilitating successful parasitization and development for parasitoid wasps, especially those devoid of polydnavirus, and the abundant venom proteins appear to be most likely involved in parasitization success. Previously, we found the four most abundant [...] Read more.

Venom injected into the host plays vital roles in facilitating successful parasitization and development for parasitoid wasps, especially those devoid of polydnavirus, and the abundant venom proteins appear to be most likely involved in parasitization success. Previously, we found the four most abundant venom proteins, including 4-coumarate:CoA ligase-like 4 (4CL4-like), in the Tetrastichus brontispae (Hymenoptera: Eulophidae) venom apparatus. In this study, we cloned, expressed T. brontispae 4CL4-like (Tb4CL4-like) in Escherichia coli, and investigated its immunosuppressive properties. The deduced amino acid sequence for Tb4CL4-like shares high identity at conserved amino acids associated with the acyl-activating enzyme (AAE) consensus motif but shows only <40% identity with the members in the AAE superfamily. mRNA abundance analysis indicated that Tb4CL4-like was transcribed mainly in the venom apparatus. Recombinant Tb4CL4-like inhibited Octodonta nipae (Coleoptera: Chrysomelidae) pupal cellular encapsulation and spreading by targeting the hemocyte cytoskeleton and reduced the hemocyte-mediated phagocytosis of E. coli in vivo. Moreover, Tb4CL4-like exhibited greater affinity to palmitic acid and linolenic acid based on the molecular docking assay and is hypothesized to be involved in fatty acid metabolism. In conclusion, our results suggest that Tb4CL4-like may be an immunity-related AAE protein that is involved in the regulation of host immunity through fatty acid metabolism-derived signaling pathways. Full article

(This article belongs to the Special Issue Animal Venoms and Their Components: Molecular Mechanisms of Action)

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11 pages, 2213 KiB

Open AccessEditor’s ChoiceArticle

An Antiviral Peptide from Alopecosa nagpag Spider Targets NS2B–NS3 Protease of Flaviviruses

by Mengyao Ji, Tengyu Zhu, Meichen Xing, Ning Luan, James Mwangi, Xiuwen Yan, Guoxiang Mo, Mingqiang Rong, Bowen Li, Ren Lai and Lin Jin

Toxins 2019, 11(10), 584; https://doi.org/10.3390/toxins11100584 - 10 Oct 2019

Cited by 27 | Viewed by 5367

Abstract

Flaviviruses are single-stranded RNA viruses predominantly transmitted by the widely distributed Aedes mosquitoes in nature. As important human pathogens, the geographic reach of Flaviviruses and their threats to public health are increasing, but there is currently no approved specific drug for treatment. In [...] Read more.

Flaviviruses are single-stranded RNA viruses predominantly transmitted by the widely distributed Aedes mosquitoes in nature. As important human pathogens, the geographic reach of Flaviviruses and their threats to public health are increasing, but there is currently no approved specific drug for treatment. In recent years, the development of peptide antivirals has gained much attention. Natural host defense peptides which uniquely evolved to protect the hosts have been shown to have antiviral properties. In this study, we firstly collected the venom of the Alopecosa nagpag spider from Shangri-La County, Yunnan Province. A defense peptide named Av-LCTX-An1a (Antiviral-Lycotoxin-An1a) was identified from the spider venom, and its anti-dengue serotype-2 virus (DENV2) activity was verified in vitro. Moreover, a real-time fluorescence-based protease inhibition assay showed that An1a functions as a DENV2 NS2B–NS3 protease inhibitor. Furthermore, we also found that An1a restricts zika virus (ZIKV) infection by inhibiting the ZIKV NS2B–NS3 protease. Together, our findings not only demonstrate that An1a might be a candidate for anti-flavivirus drug but also indicate that spider venom is a potential resource library rich in antiviral precursor molecules. Full article

(This article belongs to the Special Issue Animal Venoms and Their Components: Molecular Mechanisms of Action)

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11 pages, 1639 KiB

Open AccessEditor’s ChoiceArticle

In Vitro and In Vivo Antimalarial Activity of LZ1, a Peptide Derived from Snake Cathelicidin

by Yaqun Fang, Xiaoqin He, Pengcheng Zhang, Chuanbin Shen, James Mwangi, Cheng Xu, Guoxiang Mo, Ren Lai and Zhiye Zhang

Toxins 2019, 11(7), 379; https://doi.org/10.3390/toxins11070379 - 30 Jun 2019

Cited by 28 | Viewed by 4573

Abstract

Antimalarial drug resistance is an enormous global threat. Recently, antimicrobial peptides (AMPs) are emerging as a new source of antimalarials. In this study, an AMP LZ1 derived from snake cathelicidin was identified with antimalarial activity. In the in vitro antiplasmodial assay, LZ1 showed [...] Read more.

Antimalarial drug resistance is an enormous global threat. Recently, antimicrobial peptides (AMPs) are emerging as a new source of antimalarials. In this study, an AMP LZ1 derived from snake cathelicidin was identified with antimalarial activity. In the in vitro antiplasmodial assay, LZ1 showed strong suppression of blood stage Plasmodium falciparum (P. falciparum) with an IC50 value of 3.045 μM. In the in vivo antiplasmodial assay, LZ1 exerted a significant antimalarial activity against Plasmodium berghei (P. berghei) in a dose- and a time- dependent manner. In addition, LZ1 exhibited anti-inflammatory effects and attenuated liver-function impairment during P. berghei infection. Furthermore, by employing inhibitors against glycolysis and oxidative phosphorylation in erythrocytes, LZ1 specifically inhibited adenosine triphosphate (ATP) production in parasite-infected erythrocyte by selectively inhibiting the pyruvate kinase activity. In conclusion, the present study demonstrates that LZ1 is a potential candidate for novel antimalarials development. Full article

(This article belongs to the Special Issue Animal Venoms and Their Components: Molecular Mechanisms of Action)

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