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Lomonte B. Lys49 myotoxins, secreted phospholipase A 2-like proteins of viperid venoms: A comprehensive review. Toxicon 2023; 224:107024. [PMID: 36632869 DOI: 10.1016/j.toxicon.2023.107024] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/06/2023] [Accepted: 01/06/2023] [Indexed: 01/11/2023]
Abstract
Muscle necrosis is a potential clinical complication of snakebite envenomings, which in severe cases can lead to functional or physical sequelae such as disability or amputation. Snake venom proteins with the ability to directly damage skeletal muscle fibers are collectively referred to as myotoxins, and include three main types: cytolysins of the "three-finger toxin" protein family expressed in many elapid venoms, the so-called "small" myotoxins found in a number of rattlesnake venoms, and the widespread secreted phospholipase A2 (sPLA2) molecules. Among the latter, protein variants that conserve the sPLA2 structure, but lack such enzymatic activity, have been increasingly found in the venoms of many viperid species. Intriguingly, these sPLA2-like proteins are able to induce muscle necrosis by a mechanism independent of phospholipid hydrolysis. They are commonly referred to as "Lys49 myotoxins" since they most often present, among other substitutions, the replacement of the otherwise invariant residue Asp49 of sPLA2s by Lys. This work comprehensively reviews the historical developments and current knowledge towards deciphering the mechanism of action of Lys49 sPLA2-like myotoxins, and points out main gaps to be filled for a better understanding of these multifaceted snake venom proteins, to hopefully lead to improved treatments for snakebites.
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Affiliation(s)
- Bruno Lomonte
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, 11501, Costa Rica.
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Biochemical and functional characterization of a new recombinant phospholipase A 2 inhibitor from Crotalus durissus collilineatus snake serum. Int J Biol Macromol 2020; 164:1545-1553. [PMID: 32735921 DOI: 10.1016/j.ijbiomac.2020.07.221] [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: 05/02/2020] [Revised: 07/08/2020] [Accepted: 07/24/2020] [Indexed: 11/20/2022]
Abstract
Phospholipase A2 plays an important role in many diseases. Thus, the production of bioactive molecules, which can modulate PLA2 activity, became an important target for the pharmaceutical industry. Previously, we demonstrated the inhibitory and anti-angiogenic effect of γCdcPLI, the natural PLA2inhibitor from Crotalus durissus collilineatus. The aim of the present study was to recombinantly express the γCdcPLI inhibitor and analyze its biochemical and functional characteristics. Based on the amino acid sequence from the natural protein, we designed a synthetic gene for production of a non-tagged recombinant recγCdcPLI using the pHis-Parallel2 vector. To enable disulfide bond formation, protein expression was performed using E. coli Rosetta-gamiB. The protein was purified by anion and affinity chromatography with a yield of 5 mg/L. RecγCdcPLI showed similar secondary structure in CD and FTIR, revealing predominately β-strands. Analogous to the natural protein, recγCdcPLI was able to form oligomers of ~5.5 nm. The inhibitor was efficiently binding to PLA2 from honeybee (Kd = 1.48 μM) and was able to inhibit the PLA2 activity. Furthermore, it decreased the vessel formation in HUVEC cells, suggesting an anti-angiogenic potential. Heterologous production of recγCdcPLI is highly efficient and thus enables enhanced drug design for treatment of diseases triggered by PLA2 activity.
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Diagnostic and Therapeutic Value of Aptamers in Envenomation Cases. Int J Mol Sci 2020; 21:ijms21103565. [PMID: 32443562 PMCID: PMC7278915 DOI: 10.3390/ijms21103565] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 05/11/2020] [Accepted: 05/13/2020] [Indexed: 02/07/2023] Open
Abstract
It is now more than a century since Albert Calmette from the Institut Pasteur changed the world of envenomation by demonstrating that antibodies raised against animal venoms have the ability to treat human victims of previously fatal bites or stings. Moreover, the research initiated at that time effectively launched the discipline of toxicology, first leading to the search for toxic venom components, followed by the demonstration of venoms that also contained compounds of therapeutic value. Interest from pharmaceutical companies to treat envenomation is, however, declining, mainly for economic reasons, and hence, the World Health Organization has reclassified this public health issue to be a highest priority concern. While the production, storage, and safety of antivenom sera suffer from major inconveniences, alternative chemical and technological approaches to the problem of envenomation need to be considered that bypass the use of antibodies for toxin neutralization. Herein, we review an emerging strategy that relies on the use of aptamers and discuss how close—or otherwise—we are to finding a viable alternative to the use of antibodies for the therapy of human envenomation.
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First report on BaltCRP, a cysteine-rich secretory protein (CRISP) from Bothrops alternatus venom: Effects on potassium channels and inflammatory processes. Int J Biol Macromol 2019; 140:556-567. [DOI: 10.1016/j.ijbiomac.2019.08.108] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 08/12/2019] [Accepted: 08/12/2019] [Indexed: 12/20/2022]
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Pucca MB, Cerni FA, Janke R, Bermúdez-Méndez E, Ledsgaard L, Barbosa JE, Laustsen AH. History of Envenoming Therapy and Current Perspectives. Front Immunol 2019; 10:1598. [PMID: 31354735 PMCID: PMC6635583 DOI: 10.3389/fimmu.2019.01598] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 06/26/2019] [Indexed: 01/15/2023] Open
Abstract
Each year, millions of humans fall victim to animal envenomings, which may either be deadly or cause permanent disability to the effected individuals. The Nobel Prize-winning discovery of serum therapy for the treatment of bacterial infections (tetanus and diphtheria) paved the way for the introduction of antivenom therapies for envenomings caused by venomous animals. These antivenoms are based on polyclonal antibodies derived from the plasma of hyperimmunized animals and remain the only specific treatment against animal envenomings. Following the initial development of serum therapy for snakebite envenoming by French scientists in 1894, other countries with high incidences of animal envenomings, including Brazil, Australia, South Africa, Costa Rica, and Mexico, started taking up antivenom production against local venomous animals over the course of the twentieth century. These undertakings revolutionized envenoming therapy and have saved innumerous patients worldwide during the last 100 years. This review describes in detail the above-mentioned historical events surrounding the discovery and the application of serum therapy for envenomings, as well as it provides an overview of important developments and scientific breakthroughs that were of importance for antibody-based therapies in general. This begins with discoveries concerning the characterization of antibodies, including the events leading up to the elucidation of the antibody structure. These discoveries further paved the way for other milestones in antibody-based therapies, such as the introduction of hybridoma technology in 1975. Hybridoma technology enabled the expression and isolation of monoclonal antibodies, which in turn formed the basis for the development of phage display technology and transgenic mice, which can be harnessed to directly obtain fully human monoclonal antibodies. These developments were driven by the ultimate goal of producing potent neutralizing monoclonal antibodies with optimal pharmacokinetic properties and low immunogenicity. This review then provides an outline of the most recent achievements in antivenom research, which include the application of new biotechnologies, the development of the first human monoclonal antibodies that can neutralize animal toxins, and efforts toward creating fully recombinant antivenoms. Lastly, future perspectives in the field of envenoming therapies are discussed, including rational engineering of antibody cross-reactivity and the use of oligoclonal antibody mixtures.
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Affiliation(s)
- Manuela B. Pucca
- Medical School, Federal University of Roraima, Boa Vista, Brazil
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Felipe A. Cerni
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
- Department of Biochemistry and Immunology, Medical School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Rahel Janke
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | | | - Line Ledsgaard
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - José E. Barbosa
- Department of Biochemistry and Immunology, Medical School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Andreas H. Laustsen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
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Boldrini-França J, Pinheiro-Junior EL, Arantes EC. Functional and biological insights of rCollinein-1, a recombinant serine protease from Crotalus durissus collilineatus. J Venom Anim Toxins Incl Trop Dis 2019; 25:e147118. [PMID: 31131001 PMCID: PMC6483414 DOI: 10.1590/1678-9199-jvatitd-1471-18] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 10/01/2018] [Indexed: 12/03/2022] Open
Abstract
Background: The prevalent class of snake venom serine proteases (SVSP) in Viperidae
venoms is the thrombin-like enzymes, which, similarly to human thrombin,
convert fibrinogen into insoluble fibrin monomers. However, thrombin-like
serine proteases differ from thrombin by being unable to activate factor
XIII, thus leading to the formation of loose clots and fibrinogen
consumption. We report the functional and biological characterization of a
recombinant thrombin-like serine protease from Crotalus durissus
collilineatus, named rCollinein-1. Methods: Heterologous expression of rCollinein-1 was performed in Pichia
pastoris system according to a previously standardized
protocol, with some modifications. rCollinein-1 was purified from the
culture medium by a combination of three chromatographic steps. The
recombinant toxin was tested in vitro for its thrombolytic
activity and in mice for its edematogenicity, blood incoagulability and
effect on plasma proteins. Results: When tested for the ability to induce mouse paw edema, rCollinein-1
demonstrated low edematogenic effect, indicating little involvement of this
enzyme in the inflammatory processes resulting from ophidian accidents. The
rCollinein-1 did not degrade blood clots in vitro, which
suggests that this toxin lacks fibrinolytic activity and is not able to
directly or indirectly activate the fibrinolytic system. The minimal dose of
rCollinein-1 that turns the blood incoagulable in experimental mice is 7.5
mg/kg. The toxin also led to a significant increase in activated partial
thromboplastin time at the dose of 1 mg/kg in the animals. Other parameters
such as plasma fibrinogen concentration and prothrombin time were not
significantly affected by treatment with rCollinein-1 at this dose. The
toxin was also able to alter plasma proteins in mouse after 3 h of injection
at a dose of 1 mg/kg, leading to a decrease in the intensity of beta zone
and an increase in gamma zone in agarose gel electrophoresis Conclusion: These results suggest that the recombinant enzyme has no potential as a
thrombolytic agent but can be applied in the prevention of thrombus
formation in some pathological processes and as molecular tools in studies
related to hemostasis.
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Affiliation(s)
- Johara Boldrini-França
- School of Pharmaceutical Sciences of Ribeirão Preto - FCFRP/USP, Ribeirão Preto, São Paulo, Brazil.,Graduate Program in Ecosystem Ecology, University of Vila Velha, Av. Comissário José Dantas de Melo, 21, Boa Vista II, 29102-920, Vila Velha, ES, Brazil
| | | | - Eliane Candiani Arantes
- School of Pharmaceutical Sciences of Ribeirão Preto - FCFRP/USP, Ribeirão Preto, São Paulo, Brazil
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Vieira SM, da Rocha SLG, Neves-Ferreira AGDC, Almeida RV, Perales J. Heterologous expression of the antimyotoxic protein DM64 in Pichia pastoris. PLoS Negl Trop Dis 2017; 11:e0005829. [PMID: 28759578 PMCID: PMC5552330 DOI: 10.1371/journal.pntd.0005829] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 08/10/2017] [Accepted: 07/24/2017] [Indexed: 11/18/2022] Open
Abstract
Snakebite envenomation is a neglected condition that constitutes a public health problem in tropical and subtropical countries, including Brazil. Interestingly, some animals are resistant to snake envenomation due to the presence of inhibitory glycoproteins in their serum that target toxic venom components. DM64 is an acidic glycoprotein isolated from Didelphis aurita (opossum) serum that has been characterized as an inhibitor of the myotoxicity induced by bothropic toxins bearing phospholipase A2 (PLA2) structures. This antitoxic protein can serve as an excellent starting template for the design of novel therapeutics against snakebite envenomation, particularly venom-induced local tissue damage. Therefore, the aim of this work was to produce a recombinant DM64 (rDM64) in the methylotrophic yeast Pichia pastoris and to compare its biological properties with those of native DM64. Yeast fermentation in the presence of Pefabloc, a serine protease inhibitor, stimulated cell growth (~1.5-fold), increased the rDM64 production yield approximately 10-fold and significantly reduced the susceptibility of rDM64 to proteolytic degradation. P. pastoris fermentation products were identified by mass spectrometry and Western blotting. The heterologous protein was efficiently purified from the culture medium by affinity chromatography (with immobilized PLA2 myotoxin) and/or an ion exchange column. Although both native and recombinant DM64 exhibit different glycosylation patterns, they show very similar electrophoretic mobilities after PNGase F treatment. rDM64 formed a noncovalent complex with myotoxin II (Lys49-PLA2) from Bothrops asper and displayed biological activity that was similar to that of native DM64, inhibiting the cytotoxicity of myotoxin II by 92% at a 1:1 molar ratio. Snakebite envenomation causes medical emergencies that, depending on the species responsible for the bite, involve different organs and tissues. Envenomation by snakebite is a worldwide problem, and Brazil presents a high incidence of Bothrops bites. Bothrops venoms cause pathological alterations with prominent local effects, such as edema, blistering, hemorrhage, dermonecrosis and myonecrosis, usually followed by poor tissue regeneration and permanent sequelae. Bleeding, coagulopathy, cardiovascular shock and renal failure are typical systemic effects of these venoms. The clinical treatment for snakebite envenoming is intravenous administration of the specific antivenom. However, serotherapy does not efficiently protect against local tissue damage. Additional challenges faced by classical antivenom therapy include the wide antigenic variation of venoms across species and even within the same snake species and the frequent occurrence of adverse reactions that are associated with the administration of immunobiologicals. The development of new effective toxin inhibitors based on the structure of natural antiophidic proteins is an attractive therapeutic alternative. DM64 is a myotoxin inhibitor that was isolated from opossum serum, and its expression as a recombinant protein is paramount to the characterization of its structure-function relationship, an essential step toward the development of alternative strategies to better manage bothropic snakebite envenomations.
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Affiliation(s)
- Saulo Martins Vieira
- Laboratory of Toxinology, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, RJ, Brazil
- National Institute of Science and Technology on Toxins (INCTTOX), CNPq, Brasília, DF, Brazil
| | - Surza Lucia Gonçalves da Rocha
- Laboratory of Toxinology, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, RJ, Brazil
- National Institute of Science and Technology on Toxins (INCTTOX), CNPq, Brasília, DF, Brazil
| | - Ana Gisele da Costa Neves-Ferreira
- Laboratory of Toxinology, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, RJ, Brazil
- National Institute of Science and Technology on Toxins (INCTTOX), CNPq, Brasília, DF, Brazil
- * E-mail: (JP); (AGCNF)
| | - Rodrigo Volcan Almeida
- Laboratory of Molecular Microbiology and Proteins, Department of Biochemistry, Chemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Jonas Perales
- Laboratory of Toxinology, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, RJ, Brazil
- National Institute of Science and Technology on Toxins (INCTTOX), CNPq, Brasília, DF, Brazil
- * E-mail: (JP); (AGCNF)
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Xiong S, Luo Y, Zhong L, Xiao H, Pan H, Liao K, Yang M, Huang C. Investigation of the inhibitory potential of phospholipase A 2 inhibitor gamma from Sinonatrix annularis to snake envenomation. Toxicon 2017; 137:83-91. [PMID: 28746861 DOI: 10.1016/j.toxicon.2017.07.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2017] [Revised: 07/18/2017] [Accepted: 07/20/2017] [Indexed: 11/28/2022]
Abstract
SaPLIγ is a novel gamma phospholipase A2 inhibitor (PLI) recently isolated from Sinonatrix annularis, a Chinese endemic non-venomous snake. To explore the neutralization effects of saPLIγ in snakebite envenomation, a dose equivalent to LD50 of Deinagkistrodon acutus, Agkistrodon halys and Naja atra venom with/without saPLIγ was inoculated into the gastrocnemius muscle of female Kunming mice. The ability of saPLIγ to inhibit myonecrosis and systemic toxicity were evaluated through investigations of muscle histopathology, and determination of the serum levels of creatine kinase (CK), lactate dehydrogenase isoenzyme1 (LDH1) and aspartate transferase (AST). Edema of the gastrocnemius muscle was evaluated by calculating the width difference between the inoculated limb and the contralateral leg. Desmin loss in the gastrocnemius muscle was determined by Western blot analysis. Co-immunoprecipitation and shotgun LC-MS/MS analyses were performed to identify venom proteins that interact with saPLIγ. All the envenomed mice had significantly elevated serum CK, LDH1 and AST levels, whereas the levels were decreased significantly in the presence of saPLIγ. Histopathological evaluation of gastrocnemius muscle sections showed severe snake venom-induced damage, characterized by leukocyte infiltration and erythrocyte leakage, leading to local edema. Myonecrosis, hemorrhage and desmin loss were significantly attenuated by saPLIγ. SaPLIγ interacted with a wide range of venom proteins, including PLA2s, metalloproteinases and C type lectins, which may contribute to broad anti-venom effects.
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Affiliation(s)
- Shengwei Xiong
- Department of Biochemistry, College of Basic Medical Science, Nanchang University, Nanchang, 330006, China
| | - Yunyun Luo
- Department of Biochemistry, College of Basic Medical Science, Nanchang University, Nanchang, 330006, China
| | - Lipeng Zhong
- The Fourth Affiliated Hospital, Nanchang University, Nanchang, 330006, China
| | - Huixiang Xiao
- Department of Biochemistry, College of Basic Medical Science, Nanchang University, Nanchang, 330006, China
| | - Hong Pan
- Department of Biochemistry, College of Basic Medical Science, Nanchang University, Nanchang, 330006, China
| | - Keren Liao
- Department of Biochemistry, College of Basic Medical Science, Nanchang University, Nanchang, 330006, China
| | - Mengxue Yang
- Department of Biochemistry, College of Basic Medical Science, Nanchang University, Nanchang, 330006, China
| | - Chunhong Huang
- Department of Biochemistry, College of Basic Medical Science, Nanchang University, Nanchang, 330006, China; Jiangxi Province Key Laboratory of Tumor Pathogens and Molecular Pathology, Nanchang University, Nanchang, 330006, China.
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Santos-Filho NA, Santos CT. Alpha-type phospholipase A 2 inhibitors from snake blood. J Venom Anim Toxins Incl Trop Dis 2017; 23:19. [PMID: 28344595 PMCID: PMC5364564 DOI: 10.1186/s40409-017-0110-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 03/16/2017] [Indexed: 01/22/2023] Open
Abstract
It is of popular and scientific knowledge that toxins from snake venom (among them the PLA2 and myotoxins) are neutralized by various compounds, such as antibodies and proteins purified from animal blood. Venomous and nonvenomous snakes have PLA2 inhibitory proteins, called PLIs, in their blood serum. One hypothesis that could explain the presence of these PLIs in the serum of venomous snakes would be self-protection against the enzymes of their own venom, which eventually could reach the circulatory system. However, the presence of PLIs in non-venomous snakes suggests that their physiological role might not be restricted to protection against PLA2 toxins, but could be extended to other functions, as in the innate immune system and local regulation of PLA2s. The present study aimed to review the currently available literature on PLA2 and myotoxin alpha inhibitors present in snake plasma, thus helping to improve the research on these molecules. Furthermore, this review includes current information regarding the mechanism of action of these inhibitors in an attempt to better understand their application, and proposes the use of these molecules as new models in snakebite therapy. These molecules may help in the neutralization of different types of phospholipases A2 and myotoxins, complementing the conventional serum therapy.
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Affiliation(s)
- Norival A. Santos-Filho
- Institute of Chemistry, São Paulo State University (UNESP – Univ Estadual Paulista), Araraquara, SP Brazil
| | - Claudia T. Santos
- School of Pharmaceutical Sciences, São Paulo State University (UNESP – Univ Estadual Paulista), Araraquara, SP Brazil
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Endogenous phospholipase A 2 inhibitors in snakes: a brief overview. J Venom Anim Toxins Incl Trop Dis 2016; 22:37. [PMID: 28031735 PMCID: PMC5175389 DOI: 10.1186/s40409-016-0092-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 11/30/2016] [Indexed: 11/29/2022] Open
Abstract
The blood plasma of numerous snake species naturally comprises endogenous phospholipase A2 inhibitors, which primarily neutralize toxic phospholipases A2 that may eventually reach their circulation. This inhibitor type is generally known as snake blood phospholipase A2 inhibitors (sbPLIs). Most, if not all sbPLIs are oligomeric glycosylated proteins, although the carbohydrate moiety may not be essential for PLA2 inhibition in every case. The presently known sbPLIs belong to one of three structural classes – namely sbαPLI, sbβPLI or sbγPLI – depending on the presence of characteristic C-type lectin-like domains, leucine-rich repeats or three-finger motifs, respectively. Currently, the most numerous inhibitors described in the literature are sbαPLIs and sbγPLIs, whereas sbβPLIs are rare. When the target PLA2 is a Lys49 homolog or an Asp49 myotoxin, the sbPLI is denominated a myotoxin inhibitor protein (MIP). In this brief overview, the most relevant data on sbPLIs will be presented. Representative examples of sbαPLIs and sbγPLIs from two Old World – Gloydius brevicaudus and Malayopython reticulatus – and two New World – Bothrops alternatus and Crotalus durissus terrificus – snake species will be emphasized.
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rBaltMIP, a recombinant alpha-type myotoxin inhibitor from Bothrops alternatus (Rhinocerophis alternatus) snake, as a potential candidate to complement the antivenom therapy. Toxicon 2016; 124:53-62. [PMID: 28327300 DOI: 10.1016/j.toxicon.2016.10.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 10/24/2016] [Accepted: 10/27/2016] [Indexed: 02/04/2023]
Abstract
Phospholipase A2 inhibitors (PLIs) are important targets in the search and development of new drugs. This study aimed at evaluating the potential of an alpha-type phospholipase A2 inhibitor from Bothrops alternatus (Rhinocerophis alternatus) snake in its recombinant form (rBaltMIP) to complement the conventional antivenom therapy. Biochemical experiments showed that rBaltMIP presented pI 5.8 and molecular masses of ∼21 kDa by SDS-PAGE and 19.57 kDa by MALDI/TOF MS. After tryptic peptides sequencing, the results were compared with other PLIs available in databases, showing 100% identity between rBaltMIP and its native inhibitor BaltMIP and from 92% to 96% identity with other inhibitors. Myotoxic activities of BthTX-I and BthTX-II toxins were measured via plasma CK levels, showing myotoxic effective concentrations (EC50) of 0.1256 μg/μL and 0.6183 μg/μL, respectively. rBaltMIP neutralized the myotoxicity caused by these two toxins up to 65%, without promoting primary antibody response against itself. Nevertheless, this recombinant PLI was immunogenic when standard immunization protocol with Freud's adjuvant was used. In paw edema assays, EC50 of 0.02581 μg/μL and 0.02810 μg/μL, respectively, were observed with edema reductions of up to 40% by rBaltMIP, suggesting its use as an additional antivenom. In addition, myotoxicity neutralization experiments with the myotoxin BthTX-I showed that rBaltMIP was more effective in inhibiting muscle damage than the conventional antivenom. Thus, considering the severity of envenomations due to Bothrops alternatus (Rhinocerophis alternatus) and the low neutralization of their local effects (such as myotoxicity) by the current antivenoms, rBaltMIP is a promising molecule for the development of novel therapeutic strategies for clinical applications.
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