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Dubovskii PV, Utkin YN. Specific Amino Acid Residues in the Three Loops of Snake Cytotoxins Determine Their Membrane Activity and Provide a Rationale for a New Classification of These Toxins. Toxins (Basel) 2024; 16:262. [PMID: 38922156 PMCID: PMC11209149 DOI: 10.3390/toxins16060262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Revised: 05/23/2024] [Accepted: 05/28/2024] [Indexed: 06/27/2024] Open
Abstract
Cytotoxins (CTs) are three-finger membrane-active toxins present mainly in cobra venom. Our analysis of the available CT amino acid sequences, literature data on their membrane activity, and conformational equilibria in aqueous solution and detergent micelles allowed us to identify specific amino acid residues which interfere with CT incorporation into membranes. They include Pro9, Ser28, and Asn/Asp45 within the N-terminal, central, and C-terminal loops, respectively. There is a hierarchy in the effect of these residues on membrane activity: Pro9 > Ser28 > Asn/Asp45. Taking into account all the possible combinations of special residues, we propose to divide CTs into eight groups. Group 1 includes toxins containing all of the above residues. Their representatives demonstrated the lowest membrane activity. Group 8 combines CTs that lack these residues. For the toxins from this group, the greatest membrane activity was observed. We predict that when solely membrane activity determines the cytotoxic effects, the activity of CTs from a group with a higher number should exceed that of CTs from a group with a lower number. This classification is supported by the available data on the cytotoxicity and membranotropic properties of CTs. We hypothesize that the special amino acid residues within the loops of the CT molecule may indicate their involvement in the interaction with non-lipid targets.
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Affiliation(s)
- Peter V. Dubovskii
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya Str., 117997 Moscow, Russia;
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Saaiman Engelbrecht EL, Naidoo V, Botha CJ. Naja nigricincta nigricincta venom, a murine model. Evaluation of skeletal and cardio-myonecrosis, kidney injury and inflammatory response along with neutralisation efficacy by the SAIMR/SAVP - And EchiTAb-Plus-ICP polyvalent antivenoms. Toxicon 2024; 243:107719. [PMID: 38631492 DOI: 10.1016/j.toxicon.2024.107719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Revised: 04/06/2024] [Accepted: 04/10/2024] [Indexed: 04/19/2024]
Abstract
African spitting cobra, Naja nigricincta nigricincta (Zebra snake), envenomation is an important cause of snakebite morbidity and mortality in Namibia. The snake is endemic to central and northern Namibia as well as southern Angola. The venom is mainly cytotoxic, resulting in aggressive dermo-necrosis and often accompanied by severe systemic complications. No specific antivenom exists. Rhabdomyolysis, systemic inflammatory response, haemostatic abnormalities, infective necrotising fasciitis as well as acute kidney failure have been documented. Based on murine models, this study assessed SAVP/SAIMR - and EchiTAb-Plus-ICP polyvalent antivenom neutralisation as well as subdermal necrosis. Additional muscle, cardiac, kidney and lung histology, creatine kinase measurements and post-mortems were performed. An intravenous median lethal dose (LD50) of Naja nigricincta nigricincta venom was determined at 18.4 (CI: 16.3; 20.52) μg and a subdermal lethal dose at 15.3(CI: 12.96; 17.74)μg. The SAIMR/SAVP polyvalent antivenom median effective dose (ED50) was 1.2 ml antivenom/1 mg venom equating to a potency (WHO) of 1 ml antivenom neutralising 0.63 mg venom and approximately 240 ml (24 vials) needed for initial treatment. The ED50 of the EchiTAb-Plus-ICP was 1 ml antivenom/1 mg venom and a potency of 65 mg venom/ml antivenom (3.3 x LD50), estimating 230 ml (23 vials) for treatment. Histology and serology (creatine kinase) evidenced venom induced skeletal myotoxicity, which was not prevented by the antivenoms tested. Cardiac myonecrosis, an inflammatory response, direct venom kidney tubular necrosis and cardio-pulmonary failure were documented.
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Affiliation(s)
- Esta L Saaiman Engelbrecht
- Faculty of Veterinary Science, University of Pretoria, South Africa; Namibian Snakebite Interest Group, Namibia.
| | - Vinny Naidoo
- Faculty of Veterinary Science, University of Pretoria, South Africa
| | - Christo J Botha
- Faculty of Veterinary Science, University of Pretoria, South Africa
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Qin WG, Zhuo ZP, Hu H, Lay M, Li QQ, Huang JT, Zeng LB, Liang ZJ, Long F, Liang Q. Proteomic characteristics of six snake venoms from the Viperidae and Elapidae families in China and their relation to local tissue necrosis. Toxicon 2023; 235:107317. [PMID: 37839739 DOI: 10.1016/j.toxicon.2023.107317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 09/28/2023] [Accepted: 10/09/2023] [Indexed: 10/17/2023]
Abstract
Patients envenomed by snakes from the Viperidae and Elapidae families in China often have varying degrees of local tissue necrosis. Due to the relative clinical characteristics of local tissue necrosis and ulceration following envenoming, this study has analyzed the proteome of six snake venoms from the Viperidae and Elapidae family, and the toxin profiles of each snake were compared and correlated with the clinical manifestations that follow cytotoxic envenoming. Deinagkistrodon acutus and Naja atra envenomation induce severe ulceration, which is absent in Bungarus multicinctus envenomation and mild in the other three vipers. It is interesting to note that the proportion of c-type lectins (CTL) (20.63%) in Deinagkistrodon acutus venom was relatively high, which differs from the venom of other vipers. In addition, three-fingered toxin (3FTx) (2.15%) is present in the venom of Deinagkistrodon acutus, but has not been detected in the remaining three vipers. Snake venom metalloprotease (SVMP) (34.4%-44.7%), phospholipase A2 (PLA2) (9.81%-40.83%), and snake venom serine protease (SVSP) (9.44%-16.2%) represent the most abundant families of toxin in Viperidae venom. The Elapidae venom proteome was mainly composed of neurotoxins and cytotoxins, including 3FTx (39.28%-60.08%) and PLA2 (8.24%-58.95%) toxins, however, the proportion of CRISPS (26.36%) in Naja atra venom was relatively higher compared to Bungarus multicinctus venom. Significant differences in SVMP, SVSP, and 3FTx expression levels exist between the Viperidae and the Elapidae family. The main toxins responsible for the development of tissue necrosis and ulcerations following Viperidae envenoming are hematotoxins (SVSMP, SVSP) and myotoxins (PLA2). Deinagkistrodon acutus venom contains high levels of CTL and traces of 3FTx, leading to more severe local necrosis. However, Naja atra venom can also cause severe local necrosis through the effects of myotoxin (3FTx, CRISP, PLA2). Bungarus multicinctus venom does not contain myotoxins, resulting in pure systemic neurological manifestations no obvious necrosis of local tissue in patients.
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Affiliation(s)
- Wan-Gang Qin
- Department of Emergency Medicine, The First Affiliated Hospital of Guangzhou Medical University,151 Yanjiang Rd., Guangzhou, 510120, China
| | - Zhan-Peng Zhuo
- Department of Emergency Medicine, The First Affiliated Hospital of Guangzhou Medical University,151 Yanjiang Rd., Guangzhou, 510120, China
| | - Hao Hu
- Sino-French Hoffmann Institute, School of Basic Medical Science, Guangzhou Medical University, Guangzhou, China
| | - Mimi Lay
- Monash Venom Group, Department of Pharmacology, Biomedical Discovery Institute, Monash University, Clayton, Vic, 3800, Australia
| | - Qian-Qin Li
- Department of Emergency Medicine, The First Affiliated Hospital of Guangzhou Medical University,151 Yanjiang Rd., Guangzhou, 510120, China
| | - Jun-Ting Huang
- Department of Emergency Medicine, The First Affiliated Hospital of Guangzhou Medical University,151 Yanjiang Rd., Guangzhou, 510120, China
| | - Liang-Bo Zeng
- Department of Emergency Medicine, The First Affiliated Hospital of Guangzhou Medical University,151 Yanjiang Rd., Guangzhou, 510120, China
| | - Zi-Jing Liang
- Department of Emergency Medicine, The First Affiliated Hospital of Guangzhou Medical University,151 Yanjiang Rd., Guangzhou, 510120, China
| | - Fei Long
- Sino-French Hoffmann Institute, School of Basic Medical Science, Guangzhou Medical University, Guangzhou, China.
| | - Qing Liang
- Department of Emergency Medicine, The First Affiliated Hospital of Guangzhou Medical University,151 Yanjiang Rd., Guangzhou, 510120, China; Monash Venom Group, Department of Pharmacology, Biomedical Discovery Institute, Monash University, Clayton, Vic, 3800, Australia.
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M Morris N, A Blee J, Hauert S. Global parameter optimisation and sensitivity analysis of antivenom pharmacokinetics and pharmacodynamics. Toxicon 2023; 232:107206. [PMID: 37356552 DOI: 10.1016/j.toxicon.2023.107206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 06/05/2023] [Accepted: 06/22/2023] [Indexed: 06/27/2023]
Abstract
In recent years it has become possible to design snakebite antivenoms with diverse pharmacokinetic properties. Owing to the pharmacokinetic variability of venoms, the choice of antivenom scaffold may influence a treatment's neutralisation coverage. Computation offers a useful medium through which to assess the pharmacokinetics and pharmacodynamics of envenomation-treatment systems, as antivenoms with identical neutralising capacities can be simulated. In this study, we simulate envenomation and treatment with a variety of antivenoms, to define the properties of effective antivenoms. Systemic envenomation and treatment were described using a two-compartment pharmacokinetic model. Treatment of Naja sumatrana and Cryptelytrops purpureomaculatus envenomation was simulated with a set of 200,000 theoretical antivenoms across 10 treatment time delays. These two venoms are well-characterised and have differing pharmacokinetic properties. The theoretical antivenom set varied across molecular weight, dose, kon, koff, and valency. The best and worst treatments were identified using an area under the curve metric, and a global sensitivity analysis was performed to quantify the influence of the input parameters on treatment outcome. The simulations show that scaffolds of diverse molecular formats can be effective. Molecular weight and valency have a negligible direct impact on treatment outcome, however low molecular weight scaffolds offer more flexibility across the other design parameters, particularly when treatment is delayed. The simulations show kon to primarily mediate treatment efficacy, with rates above 105 M-1s-1 required for the most effective treatments. koff has the greatest impact on the performance of less effective scaffolds. While the same scaffold preferences for improved treatment are seen for both model snakes, the parameter bounds for C. purpureomaculatus envenomation are more constrained. This paper establishes a computational framework for the optimisation of antivenom design.
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Affiliation(s)
- Natalie M Morris
- Department of Engineering Mathematics, Ada Lovelace Building, University of Bristol, University Walk, Bristol, BS8 1TW, UK.
| | - Johanna A Blee
- Department of Engineering Mathematics, Ada Lovelace Building, University of Bristol, University Walk, Bristol, BS8 1TW, UK.
| | - Sabine Hauert
- Department of Engineering Mathematics, Ada Lovelace Building, University of Bristol, University Walk, Bristol, BS8 1TW, UK.
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Gopal G, Muralidar S, Prakash D, Kamalakkannan A, Indhuprakash ST, Thirumalai D, Ambi SV. The concept of Big Four: Road map from snakebite epidemiology to antivenom efficacy. Int J Biol Macromol 2023; 242:124771. [PMID: 37169043 DOI: 10.1016/j.ijbiomac.2023.124771] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 05/02/2023] [Accepted: 05/03/2023] [Indexed: 05/13/2023]
Abstract
Snake envenomation is a life-threatening disease caused by the injection of venom toxins from the venomous snake bite. Snakebite is often defined as the occupational or domestic hazard mostly affecting the rural population. India experiences a high number of envenoming cases and fatality due to the nation's diversity in inhabiting venomous snakes. The Indian Big Four snakes namely Russell's viper (Daboia russelii), spectacled cobra (Naja naja), common krait (Bungarus caeruleus), and saw-scaled viper (Echis carinatus) are responsible for majority of the snake envenoming cases and death. The demographic characteristics including occupation, stringent snake habitat management, poor healthcare facilities and ignorance of the rural victims are the primary influencers of high mortality. Biogeographic venom variation greatly influences the clinical pathologies of snake envenomation. The current antivenoms against the Big Four snakes are found to be less immunogenic against the venom toxins emphasizing the necessity of alternative approaches for antivenom generation. This review summarizes the burden of snake envenomation in India by the Big Four snakes including the geographic distribution of snake species and biogeographic venom variation. We have provided comprehensive information on snake venom proteomics that has aided the better understanding of venom induced pathological features, summarized the impact of current polyvalent antivenom therapy highlighting the need for potential antivenom treatment for the effective management of snakebites.
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Affiliation(s)
- Gayathri Gopal
- Biopharmaceutical Research Lab, Anusandhan Kendra-1, SASTRA Deemed-to-be-University, Thanjavur 613401, Tamil Nadu, India; School of Chemical and Biotechnology, SASTRA Deemed-to-be-University, Thanjavur 613401, Tamil Nadu, India
| | - Shibi Muralidar
- Biopharmaceutical Research Lab, Anusandhan Kendra-1, SASTRA Deemed-to-be-University, Thanjavur 613401, Tamil Nadu, India; School of Chemical and Biotechnology, SASTRA Deemed-to-be-University, Thanjavur 613401, Tamil Nadu, India
| | - Diwahar Prakash
- Biopharmaceutical Research Lab, Anusandhan Kendra-1, SASTRA Deemed-to-be-University, Thanjavur 613401, Tamil Nadu, India; School of Chemical and Biotechnology, SASTRA Deemed-to-be-University, Thanjavur 613401, Tamil Nadu, India
| | - Abishek Kamalakkannan
- Biopharmaceutical Research Lab, Anusandhan Kendra-1, SASTRA Deemed-to-be-University, Thanjavur 613401, Tamil Nadu, India; School of Chemical and Biotechnology, SASTRA Deemed-to-be-University, Thanjavur 613401, Tamil Nadu, India
| | - Srichandrasekar Thuthikkadu Indhuprakash
- Biopharmaceutical Research Lab, Anusandhan Kendra-1, SASTRA Deemed-to-be-University, Thanjavur 613401, Tamil Nadu, India; School of Chemical and Biotechnology, SASTRA Deemed-to-be-University, Thanjavur 613401, Tamil Nadu, India
| | - Diraviyam Thirumalai
- Biopharmaceutical Research Lab, Anusandhan Kendra-1, SASTRA Deemed-to-be-University, Thanjavur 613401, Tamil Nadu, India; School of Chemical and Biotechnology, SASTRA Deemed-to-be-University, Thanjavur 613401, Tamil Nadu, India
| | - Senthil Visaga Ambi
- Biopharmaceutical Research Lab, Anusandhan Kendra-1, SASTRA Deemed-to-be-University, Thanjavur 613401, Tamil Nadu, India; School of Chemical and Biotechnology, SASTRA Deemed-to-be-University, Thanjavur 613401, Tamil Nadu, India.
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The secretory phenotypes of envenomed cells: Insights into venom cytotoxicity. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2023; 133:193-230. [PMID: 36707202 DOI: 10.1016/bs.apcsb.2022.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Snake envenomation is listed as Category A Neglected Tropical Diseases (NTD) by World Health Organization, indicates a severe public health problem. The global figures for envenomation cases are estimated to be more than 1.8 million annually. Even if the affected victims survive the envenomation, they might suffer from permanent morbidity due to local envenomation. One of the most prominent local envenomation is dermonecrosis. Dermonecrosis is a pathophysiological outcome of envenomation that often causes disability in the victims due to surgical amputations, deformities, contracture, and chronic ulceration. The key venom toxins associated with this local symptom are mainly attributed to substantial levels of enzymatic and non-enzymatic toxins as well as their possible synergistic actions. Despite so, the severity of the local tissue damage is based on macroscopic observation of the bite areas. Furthermore, limited knowledge is known about the key biomarkers involved in the pathogenesis of dermonecrosis. The current immunotherapy with antivenom is also ineffective against dermonecrosis. These local effects eventually end up as sequelae. There is also a global shortage of toxins-targeted therapeutics attributed to inadequate knowledge of the actual molecular mechanisms of cytotoxicity. This chapter discusses the characterization of secretory phenotypes of dermonecrosis as an advanced tool to indicate its severity and pathogenesis in envenomation. Altogether, the secretory phenotypes of envenomed cells and tissues represent the precise characteristics of dermonecrosis caused by venom toxins.
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A current perspective on snake venom composition and constituent protein families. Arch Toxicol 2023; 97:133-153. [PMID: 36437303 DOI: 10.1007/s00204-022-03420-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 11/09/2022] [Indexed: 11/28/2022]
Abstract
Snake venoms are heterogeneous mixtures of proteins and peptides used for prey subjugation. With modern proteomics there has been a rapid expansion in our knowledge of snake venom composition, resulting in the venom proteomes of 30% of vipers and 17% of elapids being characterised. From the reasonably complete proteomic coverage of front-fanged snake venom composition (179 species-68 species of elapids and 111 species of vipers), the venoms of vipers and elapids contained 42 different protein families, although 18 were only reported in < 5% of snake species. Based on the mean abundance and occurrence of the 42 protein families, they can be classified into 4 dominant, 6 secondary, 14 minor, and 18 rare protein families. The dominant, secondary and minor categories account for 96% on average of a snake's venom composition. The four dominant protein families are: phospholipase A2 (PLA2), snake venom metalloprotease (SVMP), three-finger toxins (3FTx), and snake venom serine protease (SVSP). The six secondary protein families are: L-amino acid oxidase (LAAO), cysteine-rich secretory protein (CRiSP), C-type lectins (CTL), disintegrins (DIS), kunitz peptides (KUN), and natriuretic peptides (NP). Venom variation occurs at all taxonomic levels, including within populations. The reasons for venom variation are complex, as variation is not always associated with geographical variation in diet. The four dominant protein families appear to be the most important toxin families in human envenomation, being responsible for coagulopathy, neurotoxicity, myotoxicity and cytotoxicity. Proteomic techniques can be used to investigate the toxicological profile of a snake venom and hence identify key protein families for antivenom immunorecognition.
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Zeng L, Hou J, Ge C, Li Y, Gao J, Zhang C, Huang P, Du J, Mo Z, Liu Y, Zeng Z. Clinical study of anti-snake venom blockade in the treatment of local tissue necrosis caused by Chinese cobra (Naja atra) bites. PLoS Negl Trop Dis 2022; 16:e0010997. [PMID: 36525460 PMCID: PMC9803274 DOI: 10.1371/journal.pntd.0010997] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 12/30/2022] [Accepted: 11/29/2022] [Indexed: 12/23/2022] Open
Abstract
OBJECTIVE This study aimed to evaluate the clinical therapeutic efficacy of anti-snake venom serum blockade in treating local tissue necrosis caused by Chinese cobra (Naja atra) bites. METHODS Patients bitten by a Chinese cobra (Naja atra) (n = 50) that met the inclusion criteria were randomly divided into two groups: the experimental group (n = 25) and the control group (n = 25). The experimental group received regular as well as anti-snake venom serum blocking treatment, whereas regular treatment plus chymotrypsin blocking therapy was given to the control group. The necrotic volumes around snake wounds in these groups were detected on the first, third and seventh days. On the third day of treatment, some local tissues in the wounds were randomly selected for pathological biopsy, and the necrosis volume of the local tissue was observed. Furthermore, the amount of time required for wound healing was recorded. RESULTS On the third and seventh days post-treatment, the necrotic volume of the wound of the experimental group was much smaller than that of the control group, and the experimental group's wound healing time was shorter than that of the control group (all p < 0.05). Moreover, the pathological biopsies taken from the control group showed nuclear pyknosis, fragmentation, sparse nuclear density, and blurred edges, and the degree of necrosis was much higher than that of the experimental group. CONCLUSIONS Anti-snake venom blocking therapy is a new and improved therapy with good clinical effect on local tissue necrosis caused by Chinese cobra bites; moreover, it is superior to conventional chymotrypsin blocking therapy in the treatment of cobra bites. It can better neutralize and prevent the spread of the toxin, reduce tissue necrosis, and shorten the course of the disease by promoting healing of the wound. Furthermore, this treatment plan is also applicable to wound necrosis caused by other snake toxins, such as tissue necrosis caused by elapidae and viper families. CLINICAL TRIAL REGISTRATION This trial is registered in the Chinese Clinical Trial Registry, a primary registry of International Clinical Trial Registry Platform, World Health Organization (Registration No. ChiCTR2200059070; trial URL:http://www.chictr.org.cn/edit.aspx?pid=134353&htm=4).
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Affiliation(s)
- Linsheng Zeng
- Department of Emergency, Shenzhen Traditional Chinese Medicine Hospital, Shenzhen, China
| | - Jingjing Hou
- Department of Emergency, Shenzhen Traditional Chinese Medicine Hospital, Shenzhen, China
| | - Cuihong Ge
- Guangzhou University of Chinese Medicine, Guangzhou Panyu Central Hospital,Guangzhou,China
| | - Yanjun Li
- Department of Emergency, Shenzhen Traditional Chinese Medicine Hospital, Shenzhen, China
| | - Jianhua Gao
- Department of Emergency, Shenzhen Traditional Chinese Medicine Hospital, Shenzhen, China
| | - Congcong Zhang
- Department of Emergency, Shenzhen Traditional Chinese Medicine Hospital, Shenzhen, China
| | - Peiying Huang
- The Second Clinical Medical School of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Jiayu Du
- Department of Emergency, Shenzhen Traditional Chinese Medicine Hospital, Shenzhen, China
| | - Zhizhun Mo
- Department of Emergency, Shenzhen Traditional Chinese Medicine Hospital, Shenzhen, China
| | - Yuxiang Liu
- Department of Emergency, Shenzhen Traditional Chinese Medicine Hospital, Shenzhen, China
- * E-mail: (YL); (ZZ)
| | - Zhongyi Zeng
- Department of Emergency, Shenzhen Traditional Chinese Medicine Hospital, Shenzhen, China
- * E-mail: (YL); (ZZ)
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Kalita B, Utkin YN, Mukherjee AK. Current Insights in the Mechanisms of Cobra Venom Cytotoxins and Their Complexes in Inducing Toxicity: Implications in Antivenom Therapy. Toxins (Basel) 2022; 14:toxins14120839. [PMID: 36548736 PMCID: PMC9780984 DOI: 10.3390/toxins14120839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 11/21/2022] [Accepted: 11/22/2022] [Indexed: 12/02/2022] Open
Abstract
Cytotoxins (CTXs), an essential class of the non-enzymatic three-finger toxin family, are ubiquitously present in cobra venoms. These low-molecular-mass toxins, contributing to about 40 to 60% of the cobra venom proteome, play a significant role in cobra venom-induced toxicity, more prominently in dermonecrosis. Structurally, CTXs contain the conserved three-finger hydrophobic loops; however, they also exhibit a certain degree of structural diversity that dictates their biological activities. In their mechanism, CTXs mediate toxicity by affecting cell membrane structures and membrane-bound proteins and activating apoptotic and necrotic cell death pathways. Notably, some CTXs are also responsible for depolarizing neurons and heart muscle membranes, thereby contributing to the cardiac failure frequently observed in cobra-envenomed victims. Consequently, they are also known as cardiotoxins (CdTx). Studies have shown that cobra venom CTXs form cognate complexes with other components that potentiate the toxic effects of the venom's individual component. This review focuses on the pharmacological mechanism of cobra venom CTXs and their complexes, highlighting their significance in cobra venom-induced pathophysiology and toxicity. Furthermore, the potency of commercial antivenoms in reversing the adverse effects of cobra venom CTXs and their complexes in envenomed victims has also been discussed.
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Affiliation(s)
- Bhargab Kalita
- Amrita School of Nanosciences and Molecular Medicine, Amrita Vishwa Vidyapeetham, Kochi 682041, India
| | - Yuri N. Utkin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia
| | - Ashis K. Mukherjee
- Institute of Advanced Study in Science and Technology, Guwahati 781035, India
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur 784028, India
- Correspondence:
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Hiu JJ, Yap MKK. The myth of cobra venom cytotoxin: More than just direct cytolytic actions. Toxicon X 2022; 14:100123. [PMID: 35434602 PMCID: PMC9011113 DOI: 10.1016/j.toxcx.2022.100123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 03/03/2022] [Accepted: 03/31/2022] [Indexed: 12/26/2022] Open
Abstract
Cobra venom cytotoxin (CTX) is a non-enzymatic three-finger toxin that constitutes 40-60% of cobra venom. Thus, it plays an important role in the pathophysiology of cobra envenomation, especially in local dermonecrosis. The three-finger hydrophobic loops of CTX determine the cytotoxicity. Nevertheless, the actual mechanisms of cytotoxicity are not fully elucidated as they involve not only cytolytic actions but also intracellular signalling-mediated cell death pathways. Furthermore, the possible transition cell death pattern remains to be explored. The actual molecular mechanisms require further studies to unveil the relationship between different CTXs from different cobra species and cell types which may result in differential cell death patterns. Here, we discuss the biophysical interaction of CTX with the cell membrane involving four binding modes: electrostatic interaction, hydrophobic partitioning, isotropic phase, and oligomerisation. Oligomerisation of CTX causes pore formation in the membrane lipid bilayer. Additionally, the CTX-induced apoptotic pathway can be executed via death receptor-mediated extrinsic pathways and mitochondrial-mediated intrinsic pathways. We also discuss lysosomal-mediated necrosis and the occurrence of necroptosis following CTX action. Collectively, we provided an insight into concentration-dependent transition of cell death pattern which involves different mechanistic actions. This contributes a new direction for further investigation of cytotoxic pathways activated by the CTXs for future development of biotherapeutics targeting pathological effects caused by CTX.
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Affiliation(s)
- Jia Jin Hiu
- School of Science, Monash University Malaysia, Bandar Sunway, Malaysia
| | - Michelle Khai Khun Yap
- School of Science, Monash University Malaysia, Bandar Sunway, Malaysia.,Tropical Medicine and Biology Multidisciplinary Platform, Monash University Malaysia, Bandar Sunway, Malaysia
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