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Offor BC, Piater LA. A comparison of the venom proteomes and potential therapeutics of 3 African naja subgenera. Toxicon 2024; 245:107792. [PMID: 38838860 DOI: 10.1016/j.toxicon.2024.107792] [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: 05/15/2024] [Revised: 05/28/2024] [Accepted: 05/30/2024] [Indexed: 06/07/2024]
Abstract
African cobras (Naja species) represent one of the most encountered medically important snakes in Africa. They are classified as African spitting (Afronaja subgenus) and non-spitting cobras (Uraeus and Boulengerina subgenera) with similar and different characteristics. Snake venom toxins including three-finger toxin (3FTx), phospholipase A2 (PLA2), and snake venom metalloproteinase (SVMP) cause snakebite envenomation leading to morbidity and mortality. The profile of the proteome of African cobra venoms will help to develop safer and more effective antivenoms. The approval of Captopril by the US Food and Drug Administration (FDA) for the treatment of cardiovascular diseases, has led to intensified research towards possible use of venom toxins as therapeutics. In this review, we compare the venom proteome profile of 3 African Naja subgenera. In both Afronaja and Boulengerina subgenera, 3FTx (Afronaja-69.79%; Boulengerina-60.56%) followed by PLA2 (Afronaja-21.15%; Boulengerina-20.21%) dominated the venoms compared to the Uraeus subgenus dominated by 3FTx (84.55%) with little to no PLA2 abundance (0.8%). The venom of subgenus Uraeus was distinct from the other two subgenera by the almost total absence of PLA2, thus indicating little or no contribution of PLA2 in the envenomation caused by Uraeus compared to Afronaja and Boulengerina. Furthermore, we report studies on the experimental testing of African cobra venoms and toxins against diseases including anti-cancer properties.
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Affiliation(s)
- Benedict C Offor
- Department of Biochemistry, University of Johannesburg, Auckland Park, 2006, South Africa
| | - Lizelle A Piater
- Department of Biochemistry, University of Johannesburg, Auckland Park, 2006, South Africa.
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2
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Alfa-Ibrahim Adio A, Malami I, Lawal N, Jega AY, Abubakar B, Bello MB, Ibrahim KG, Abubakar MB, Abdussamad A, Imam MU. Neurotoxic Snakebites in Africa: Clinical Implications, Therapeutic Strategies, and Antivenom Efficacy. Toxicon 2024:107811. [PMID: 38917892 DOI: 10.1016/j.toxicon.2024.107811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Revised: 05/23/2024] [Accepted: 06/16/2024] [Indexed: 06/27/2024]
Abstract
Snakebite is a significant health concern in Africa, particularly due to neurotoxic envenomation which can lead to neuromuscular paralysis and respiratory failure. In Nigeria, snakes from the Elapidae family are a notable cause of envenomation cases, though these incidents are underreported. This review examined case reports of neurotoxic envenomation in Africa, highlighting the clinical impacts and the efficacy of available antivenoms. Preclinical studies showed that the polyvalent antivenom from the South African Institute for Medical Research (SAIMR) was highly effective against neurotoxicity with a protective efficacy (R) of 1346.80 mg/mL, while clinical assessment emphasized the need for high-dose antivenom therapy along with supportive measures like mechanical ventilation. Unlike hemorrhagic envenomation, where antivenom promptly resolves bleeding, neurotoxic cases often require additional interventions. The review underscores the necessity for tailored approaches in antivenom therapy to address the complexities of neurotoxic snakebites and reduce their public health burden in Africa.
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Affiliation(s)
- Abdulbaki Alfa-Ibrahim Adio
- Centre for Advanced Medical Research and Training, Usmanu Danfodiyo University, Sokoto, Nigeria; Department of Biochemistry and Molecular Biology, Faculty of Chemical and Life Sciences, Usmanu Danfodiyo University, Sokoto, Nigeria
| | - Ibrahim Malami
- Centre for Advanced Medical Research and Training, Usmanu Danfodiyo University, Sokoto, Nigeria; Department of Pharmacognosy and Ethnopharmacy, Faculty of Pharmaceutical Sciences, Usmanu Danfodiyo University, Sokoto, Nigeria
| | - Nafiu Lawal
- Centre for Advanced Medical Research and Training, Usmanu Danfodiyo University, Sokoto, Nigeria; Department of Veterinary Microbiology, Faculty of Veterinary Medicine, Usmanu Danfodiyo University, Sokoto, Nigeria
| | - Amina Yusuf Jega
- Department of Pharmaceutical and Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Usmanu Danfodiyo University, Sokoto, Nigeria
| | - Bilyaminu Abubakar
- Centre for Advanced Medical Research and Training, Usmanu Danfodiyo University, Sokoto, Nigeria; Department of Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences, Usmanu Danfodiyo University, Sokoto, Nigeria
| | - Muhammad Bashir Bello
- Centre for Advanced Medical Research and Training, Usmanu Danfodiyo University, Sokoto, Nigeria; Department of Veterinary Microbiology, Faculty of Veterinary Medicine, Usmanu Danfodiyo University, Sokoto, Nigeria; Vaccine Development Unit, Infectious Disease Research Development, King Abdullah International Medical Research Center, Riyadh, Saudi Arabia
| | - Kasimu Ghandi Ibrahim
- Centre for Advanced Medical Research and Training, Usmanu Danfodiyo University, Sokoto, Nigeria; Department of Basic Medical and Dental Sciences, Faculty of Dentistry, Zarqa University, P.O. Box 2000, Zarqa 13110, Jordan; Department of Physiology, Faculty of Basic Medical Sciences, College of Health Sciences, Usmanu Danfodiyo University, Sokoto, Nigeria
| | - Murtala Bello Abubakar
- Centre for Advanced Medical Research and Training, Usmanu Danfodiyo University, Sokoto, Nigeria; Department of Physiology, Faculty of Basic Medical Sciences, College of Health Sciences, Usmanu Danfodiyo University, Sokoto, Nigeria
| | - Abdussamad Abdussamad
- Department of Veterinary Physiology and Biochemistry, Faculty of Veterinary Medicine, Bayero University, Kano
| | - Mustapha Umar Imam
- Centre for Advanced Medical Research and Training, Usmanu Danfodiyo University, Sokoto, Nigeria; Department of Medical Biochemistry, Faculty of Basic Medical Sciences, College of Health Sciences, Usmanu Danfodiyo University, Sokoto, Nigeria.
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Kumar R, Rathore AS. Snakebite Management: The Need of Reassessment, International Relations, and Effective Economic Measures to Reduce the Considerable SBE Burden. J Epidemiol Glob Health 2024:10.1007/s44197-024-00247-z. [PMID: 38856820 DOI: 10.1007/s44197-024-00247-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 05/20/2024] [Indexed: 06/11/2024] Open
Abstract
The sole treatment for snakebite envenomation (SBE), the anti-snake venom (ASV), suffers from considerable drawbacks, including side effects and limited species specificity. Additionally, despite its existence for more than a century, uniform availability of good quality ASV does not yet exist. The present review describes the journey of a SBE victim and highlights the global crisis of SBE management. A detailed analysis of the current ASV market has also been presented along with the worldwide snake distribution. The current production of country specific licensed ASV throughout the globe along with their manufacturers has been examined at the snake species level. Furthermore, a detailed analysis of on-ground situation of SBE management in antivenom manufacturing countries has been done using the most recent literature. Additionally, the export and import of different ASVs have been discussed in terms of procurement policies of individual countries, their shortcomings, along with the possible solution at the species level. It is interesting to note that in most countries, the existence of ASV is really either neglected or overstated, implying that it is there but unsuitable for use, or that it is not present but can be obtained from other countries. This highlights the urgent need of significant reassessment and international collaborations not just for development and production, but also for procurement, distribution, availability, and awareness. A PROMISE (Practical ROutes for Managing Indigenous Snakebite Envenoming) approach has also been introduced, offering simple, economical, and easy to adopt steps to efficiently alleviate the worldwide SBE burden.
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Affiliation(s)
- Ramesh Kumar
- Department of Chemical Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, India
| | - Anurag S Rathore
- Department of Chemical Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, India.
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Araya X, Okumu M, Durán G, Gómez A, Gutiérrez JM, León G. Assessment of the Artemia salina toxicity assay as a substitute of the mouse lethality assay in the determination of venom-induced toxicity and preclinical efficacy of antivenom. Toxicon X 2024; 22:100195. [PMID: 38606385 PMCID: PMC11004356 DOI: 10.1016/j.toxcx.2024.100195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 03/09/2024] [Accepted: 03/18/2024] [Indexed: 04/13/2024] Open
Abstract
Mice are routinely used in snake venom research but are costly and subject to pain and suffering. The crustacean Artemia salina could be an alternative to mice, but data to support its adoption in snake venom research is limited. The aim of the present study was to evaluate the suitability of A. salina as a surrogate of mice in assessing the toxicity of venoms and the preclinical efficacy of antivenoms. The toxicity of venoms from 22 snakes of medical importance in sub-Saharan Africa was evaluated in mice (intraperitoneally; i.p. and intravenously; i.v.) and in A. salina. Subsequently, the capacity of a commercial antivenom to neutralize the toxicity of these venoms in mice and A. salina was investigated. There was a positive correlation between the i.v. median lethal doses (LD50s) and the i.p. LD50s in mice (r = 0.804; p < 0.0001), a moderate correlation between the i.v. LD50s in mice and the median lethal concentrations (LC50s) in A. salina (r = 0.606; p = 0.003), and a moderate correlation between the i.p. LD50s in mice and the LC50s in A. salina (r = 0.426; p = 0.048). Moreover, there was a strong correlation between the i.p. median effective doses (ED50s) and the i.v. ED50s in mice (r = 0.941, p < 0.0001), between the i.p. ED50s in mice and the ED50s in A. salina (r = 0.818, p < 0.0001), and between the i.v. ED50s in mice and the ED50s in A. salina (r = 0.972, p < 0.0001). These findings present A. salina as a promising candidate for reducing reliance on mice in snake venom research. Future investigations should build upon these findings, addressing potential limitations and expanding the scope of A. salina in venom research and antivenom development.
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Affiliation(s)
- Xavier Araya
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Mitchel Okumu
- Department of Public Health, Pharmacology and Toxicology, University of Nairobi, Kenya
| | - Gina Durán
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Aarón Gómez
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - José María Gutiérrez
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Guillermo León
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
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Offor BC, Piater LA. Snake venom toxins: Potential anticancer therapeutics. J Appl Toxicol 2024; 44:666-685. [PMID: 37697914 DOI: 10.1002/jat.4544] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/21/2023] [Accepted: 08/29/2023] [Indexed: 09/13/2023]
Abstract
Snake venom contains a cocktail of compounds dominated by proteins and peptides, which make up the toxin. The toxin components of snake venom attack several targets in the human body including the neuromuscular system, kidney and blood coagulation system and cause pathologies. As such, the venom toxins can be managed and used for the treatment of these diseases. In this regard, Captopril used in the treatment of cardiovascular diseases was the first animal venom toxin-based drug approved by the US Food and Drug Administration and the European Medicines Agency. Cancers cause morbidity and mortality worldwide. Due to side effects associated with the current cancer treatments including chemotherapy, radiotherapy, immunotherapy, hormonal therapy and surgery, there is a need to improve the efficacy of current treatments and/or develop novel drugs from natural sources including animal toxin-based drugs. There is a long history of earlier and ongoing studies implicating snake venom toxins as potential anticancer therapies. Here, we review the role of crude snake venoms and toxins including phospholipase A2, L-amino acid oxidase, C-type lectin and disintegrin as potential anticancer agents tested in cancer cell lines and animal tumour models in comparison to normal cell lines. Some of the anti-tumour activities of snake venom toxins include induction of cytotoxicity, apoptosis, cell cycle arrest and inhibition of metastasis, angiogenesis and tumour growth. We thus propose the advancement of multidisciplinary approaches to more pre-clinical and clinical studies for enhanced bioavailability and targeted delivery of snake venom toxin-based anticancer drugs.
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Affiliation(s)
- Benedict C Offor
- Department of Biochemistry, University of Johannesburg, Auckland Park, South Africa
| | - Lizelle A Piater
- Department of Biochemistry, University of Johannesburg, Auckland Park, South Africa
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Machado Marinho AC, Chapeaurouge A, Dutra BM, Quintela BCSF, Pereira SS, Fernandes CFC. The role of venom proteomics and single-domain antibodies for antivenoms: Progress in snake envenoming treatment. Drug Discov Today 2024; 29:103967. [PMID: 38555033 DOI: 10.1016/j.drudis.2024.103967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 03/14/2024] [Accepted: 03/26/2024] [Indexed: 04/02/2024]
Abstract
Single-domain antibodies (sdAbs) hold promise for developing new biopharmaceuticals to treat neglected tropical diseases (NTDs), including snakebites, which are severe and occur frequently. In addition, limitations of conventional snakebite treatments, especially in terms of local action, and the global antivenom crisis incentivize the use of this biotechnological tool to design next-generation snakebite antivenoms. Conventional antivenoms for snakebite treatment are usually composed of immunoglobulin G or F(ab')2 fragments derived from the plasma of immunized animals. sdAbs, the smallest antigen-binding fragments, are derived from the variable domains of camelid heavy-chain antibodies. sdAbs may have some advantages over conventional antivenoms for local toxicity, such as better penetration into tissues due to their small size, and high solubility and affinity for venom antigens due to their unique antigen-binding loops and ability to access cryptic epitopes. We present an overview of current antivenom therapy in the context of sdAb development for toxin neutralization. Furthermore, strategies are presented for identifying snake venom's major toxins as well as for developing antisnake toxin sdAbs by employing proteomic tools for toxin neutralization.
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Affiliation(s)
- Anna Carolina Machado Marinho
- Laboratório Multiusuário de Pesquisa e Desenvolvimento, Fundação Oswaldo Cruz Ceará, FIOCRUZ CE, Eusébio-CE, Brazil; Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal do Ceará, UFC, Fortaleza, Brazil
| | - Alexander Chapeaurouge
- Laboratório Multiusuário de Pesquisa e Desenvolvimento, Fundação Oswaldo Cruz Ceará, FIOCRUZ CE, Eusébio-CE, Brazil
| | - Brunheld Maia Dutra
- Laboratório Multiusuário de Pesquisa e Desenvolvimento, Fundação Oswaldo Cruz Ceará, FIOCRUZ CE, Eusébio-CE, Brazil
| | - Barbara Cibelle S F Quintela
- Laboratório Multiusuário de Pesquisa e Desenvolvimento, Fundação Oswaldo Cruz Ceará, FIOCRUZ CE, Eusébio-CE, Brazil
| | - Soraya S Pereira
- Laboratório de Engenharia de Anticorpos, Fundação Oswaldo Cruz Rondônia, FIOCRUZ RO, Porto Velho-RO, Brazil
| | - Carla Freire C Fernandes
- Laboratório Multiusuário de Pesquisa e Desenvolvimento, Fundação Oswaldo Cruz Ceará, FIOCRUZ CE, Eusébio-CE, Brazil; Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal do Ceará, UFC, Fortaleza, Brazil
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7
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Wang CR, Harlington AC, Snel MF, Pukala TL. Characterisation of the forest cobra (Naja melanoleuca) venom using a multifaceted mass spectrometric-based approach. BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2024; 1872:140992. [PMID: 38158032 DOI: 10.1016/j.bbapap.2023.140992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 12/20/2023] [Accepted: 12/25/2023] [Indexed: 01/03/2024]
Abstract
Snake venoms consist of highly biologically active proteins and peptides that are responsible for the lethal physiological effects of snakebite envenomation. In order to guide the development of targeted antivenom strategies, comprehensive understanding of venom compositions and in-depth characterisation of various proteoforms, often not captured by traditional bottom-up proteomic workflows, is necessary. Here, we employ an integrated 'omics' and intact mass spectrometry (MS)-based approach to profile the heterogeneity within the venom of the forest cobra (Naja melanoleuca), adopting different analytical strategies to accommodate for the dynamic molecular mass range of venom proteins present. The venom proteome of N. melanoleuca was catalogued using a venom gland transcriptome-guided bottom-up proteomics approach, revealing a venom consisting of six toxin superfamilies. The subtle diversity present in the venom components was further explored using reversed phase-ultra performance liquid chromatography (RP-UPLC) coupled to intact MS. This approach showed a significant increase in the number of venom proteoforms within various toxin families that were not captured in previous studies. Furthermore, we probed at the higher-order structures of the larger venom proteins using a combination of native MS and mass photometry and revealed significant structural heterogeneity along with extensive post-translational modifications in the form of glycosylation in these larger toxins. Here, we show the diverse structural heterogeneity of snake venom proteins in the venom of N. melanoleuca using an integrated workflow that incorporates analytical strategies that profile snake venom at the proteoform level, complementing traditional venom characterisation approaches.
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Affiliation(s)
- C Ruth Wang
- Discipline of Chemistry, School of Physics, Chemistry and Earth Sciences, The University of Adelaide, Adelaide 5005, Australia
| | - Alix C Harlington
- Department of Molecular and Biomedical Science, School of Biological Sciences, The University of Adelaide, Adelaide 5005, Australia
| | - Marten F Snel
- Discipline of Chemistry, School of Physics, Chemistry and Earth Sciences, The University of Adelaide, Adelaide 5005, Australia; Proteomics, Metabolomics and MS-Imaging Core Facility, South Australian Health and Medical Research Institute, Adelaide 5005, Australia
| | - Tara L Pukala
- Discipline of Chemistry, School of Physics, Chemistry and Earth Sciences, The University of Adelaide, Adelaide 5005, Australia.
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Niu X, Lu H, Shi M, Wang S, Zhou Y, Liu H. Genome assembly and annotation of the Brown-Spotted Pit viper Protobothrops mucrosquamatus. GIGABYTE 2023; 2023:gigabyte97. [PMID: 38023064 PMCID: PMC10644238 DOI: 10.46471/gigabyte.97] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 10/26/2023] [Indexed: 12/01/2023] Open
Abstract
The Brown-Spotted Pit viper (Protobothrops mucrosquamatus), also known as the Chinese habu, is a widespread and highly venomous snake distributed from Northeastern India to Eastern China. Genomics research can contribute to our understanding of venom components and natural selection in vipers. Here, we collected, sequenced and assembled the genome of a male P. mucrosquamatus individual from China. We generated a highly continuous reference genome, with a length of 1.53 Gb and 41.18% of repeat elements content. Using this genome, we identified 24,799 genes, 97.97% of which could be annotated. We verified the validity of our genome assembly and annotation process by generating a phylogenetic tree based on the nuclear genome single-copy genes of six other reptile species. The results of our research will contribute to future studies on Protobothrops biology and the genetic basis of snake venom.
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Affiliation(s)
- Xiaotong Niu
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen, 518083, China
- School of Ecology, Sun Yat-sen University, Shenzhen, 510275, China
| | - Haorong Lu
- BGI-Shenzhen, Shenzhen, 518083, China
- China National GeneBank, BGI-Shenzhen, Shenzhen, 518120, China
| | - Minhui Shi
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen, 518083, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Shiqing Wang
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen, 518083, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yajie Zhou
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen, 518083, China
- China National GeneBank, BGI-Shenzhen, Shenzhen, 518120, China
| | - Huan Liu
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen, 518083, China
- China National GeneBank, BGI-Shenzhen, Shenzhen, 518120, China
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9
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Hiu JJ, Fung JKY, Tan HS, Yap MKK. Unveiling the functional epitopes of cobra venom cytotoxin by immunoinformatics and epitope-omic analyses. Sci Rep 2023; 13:12271. [PMID: 37507457 PMCID: PMC10382524 DOI: 10.1038/s41598-023-39222-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 07/21/2023] [Indexed: 07/30/2023] Open
Abstract
Approximate 70% of cobra venom is composed of cytotoxin (CTX), which is responsible for the dermonecrotic symptoms of cobra envenomation. However, CTX is generally low in immunogenicity, and the antivenom is ineffective in attenuating its in vivo toxicity. Furthermore, little is known about its epitope properties for empirical antivenom therapy. This study aimed to determine the epitope sequences of CTX using the immunoinformatic analyses and epitope-omics profiling. A conserved CTX was used in this study to determine its T-cell and B-cell epitope sequences using immunoinformatic tools and molecular docking simulation with different Human Leukocyte Antigens (HLAs). The potential T-cell and B-cell epitopes were 'KLVPLFY,' 'CPAGKNLCY,' 'MFMVSTPTK,' and 'DVCPKNSLL.' Molecular docking simulations disclosed that the HLA-B62 supertype exhibited the greatest binding affinity towards cobra venom cytotoxin. The namely L7, G18, K19, N20, M25, K33, V43, C44, K46, N47, and S48 of CTX exhibited prominent intermolecular interactions with HLA-B62. The multi-enzymatic-limited-digestion/liquid chromatography-mass spectrometry (MELD/LC-MS) also revealed three potential epitope sequences as 'LVPLFYK,' 'MFMVS,' and 'TVPVKR'. From different epitope mapping approaches, we concluded four potential epitope sites of CTX as 'KLVPLFYK', 'AGKNL', 'MFMVSTPKVPV' and 'DVCPKNSLL'. Site-directed mutagenesis of these epitopes confirmed their locations at the functional loops of CTX. These epitope sequences are crucial to CTX's structural folding and cytotoxicity. The results concluded the epitopes that resided within the functional loops constituted potential targets to fabricate synthetic epitopes for CTX-targeted antivenom production.
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Affiliation(s)
- Jia Jin Hiu
- School of Science, Monash University Malaysia, 47500, Bandar Sunway, Malaysia
| | - Jared Kah Yin Fung
- School of Science, Monash University Malaysia, 47500, Bandar Sunway, Malaysia
| | - Hock Siew Tan
- School of Science, Monash University Malaysia, 47500, Bandar Sunway, Malaysia
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Chan YW, Tan CH, Heh CH, Tan KY. An immunoinformatic approach to assessing the immunogenic capacity of alpha-neurotoxins in elapid snake venoms. Front Pharmacol 2023; 14:1143437. [PMID: 37153801 PMCID: PMC10155835 DOI: 10.3389/fphar.2023.1143437] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 03/27/2023] [Indexed: 05/10/2023] Open
Abstract
Introduction: Most elapid snakes produce venoms that contain alpha-neurotoxins (α-NTXs), which are proteins that cause post-synaptic blockade and paralysis in snakebite envenoming. However, existing elapid antivenoms are known for their low potency in neutralizing the neurotoxic activity of α-NTXs, while the immunological basis has not been elucidated. Methods: In this study, a structure-based major histocompatibility complex II (MHCII) epitope predictor of horse (Equus caballus), complemented with DM-editing determinant screening algorithm was adopted to assess the immunogenicity of α-NTXs in the venoms of major Asiatic elapids (Naja kaouthia, Ophiophagus hannah, Laticauda colubrina, Hydrophis schistosus, Hydrophis curtus). Results: The scoring metric M2R, representing the relative immunogenic performance of respective α-NTXs, showed all α-NTXs have an overall low M2R of <0.3, and most of the predicted binders feature non-optimal P1 anchor residues. The M2R scores correlate strongly (R2 = 0.82) with the potency scores (p-score) generated based on the relative abundances of α-NTXs and the neutralization potency of commercial antivenoms. Discussion: The immunoinformatic analysis indicates that the inferior antigenicity of α-NTXs is not only due to their small molecular size but also the subpar immunogenicity affected by their amino acid composition. Structural modification with conjugation and synthetic epitope as immunogen may potentially enhance the immunogenicity for improved antivenom potency against α-NTXs of elapid snakes.
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Affiliation(s)
- Yi Wei Chan
- Protein and Interactomics Laboratory, Department of Molecular Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Choo Hock Tan
- Venom Research and Toxicology Laboratory, Department of Pharmacology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Choon Han Heh
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Malaya, Kuala Lumpur, Malaysia
| | - Kae Yi Tan
- Protein and Interactomics Laboratory, Department of Molecular Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
- *Correspondence: Kae Yi Tan,
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