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Kowalski K, Marciniak P, Nekaris KAI, Rychlik L. Proteins from shrews' venom glands play a role in gland functioning and venom production. ZOOLOGICAL LETTERS 2024; 10:12. [PMID: 39010181 PMCID: PMC11251227 DOI: 10.1186/s40851-024-00236-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 06/25/2024] [Indexed: 07/17/2024]
Abstract
Venom production has evolved independently many times in the animal kingdom, although it is rare among mammals. Venomous shrews produce venom in their submandibular salivary glands and use it for food acquisition. Only a few toxins have been identified in shrew venoms thus far, and their modes of action require investigation. The biological and molecular processes relating to venom production and gland functioning also remain unknown. To address this gap, we investigated protein content in extracts from venom glands of two shrew species, Neomys fodiens and Sorex araneus, and interpreted their biological functions. Applying a proteomic approach coupled with Gene Ontology enrichment analysis, we identified 313 and 187 putative proteins in venom glands of N. fodiens and S. araneus, respectively. A search of the UniProt database revealed that most of the proteins found in both shrew species were involved in metabolic processes and stress response, while GO enrichment analysis revealed more stress-related proteins in the glands of S. araneus. Molecules that regulate molecule synthesis, cell cycles, and cell divisions are necessary to enable venom regeneration and ensure its effectiveness in predation and food hoarding. The presence of proteins involved in stress response may be the result of shrews' high metabolic rate and the costs of venom replenishment. Some proteins are likely to promote toxin spreading during envenomation and, due to their proteolytic action, reinforce venom toxicity. Finally, finding numerous proteins involved in immune response suggests a potential role of shrew venom gland secretions in protection against pathogens. These findings open up new perspectives for studying biological functions of molecules from shrew venom glands and extend our knowledge on the functioning of eulipotyphlan venom systems. Because the majority of existing and putative venomous mammals use oral venom systems to inject venom into target species, the methods presented here provide a promising avenue for confirming or discovering new taxa of venomous mammals.
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Affiliation(s)
- Krzysztof Kowalski
- Department of Vertebrate Zoology and Ecology, Institute of Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Lwowska 1, Toruń, 87-100, Poland.
| | - Paweł Marciniak
- Department of Animal Physiology and Developmental Biology, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 6, Poznań, 61-614, Poland
| | - K Anne-Isola Nekaris
- Centre for Functional Genomics, Department of Health and Life Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
| | - Leszek Rychlik
- Department of Systematic Zoology, Institute of Environmental Biology, Faculty of Biology, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 6, Poznań, 61-614, Poland
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Yano Y, Fukuoka R, Maturana AD, Ohdachi SD, Kita M. Mammalian neurotoxins, Blarina paralytic peptides, cause hyperpolarization of human T-type Ca channel hCa v3.2 activation. J Biol Chem 2023; 299:105066. [PMID: 37468103 PMCID: PMC10493266 DOI: 10.1016/j.jbc.2023.105066] [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: 03/20/2023] [Revised: 07/05/2023] [Accepted: 07/14/2023] [Indexed: 07/21/2023] Open
Abstract
Among the rare venomous mammals, the short-tailed shrew Blarina brevicauda has been suggested to produce potent neurotoxins in its saliva to effectively capture prey. Several kallikrein-like lethal proteases have been identified, but the active substances of B. brevicauda remained unclear. Here, we report Blarina paralytic peptides (BPPs) 1 and 2 isolated from its submaxillary glands. Synthetic BPP2 showed mealworm paralysis and a hyperpolarization shift (-11 mV) of a human T-type Ca2+ channel (hCav3.2) activation. The amino acid sequences of BPPs were similar to those of synenkephalins, which are precursors of brain opioid peptide hormones that are highly conserved among mammals. However, BPPs rather resembled centipede neurotoxic peptides SLPTXs in terms of disulfide bond connectivity and stereostructure. Our results suggested that the neurotoxin BPPs were the result of convergent evolution as homologs of nontoxic endogenous peptides that are widely conserved in mammals. This finding is of great interest from the viewpoint of the chemical evolution of vertebrate venoms.
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Affiliation(s)
- Yusuke Yano
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Ryo Fukuoka
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Andres D Maturana
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Satoshi D Ohdachi
- Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
| | - Masaki Kita
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan.
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Fitzpatrick LLJ, Ligabue-Braun R, Nekaris KAI. Slowly Making Sense: A Review of the Two-Step Venom System within Slow ( Nycticebus spp.) and Pygmy Lorises ( Xanthonycticebus spp.). Toxins (Basel) 2023; 15:514. [PMID: 37755940 PMCID: PMC10536643 DOI: 10.3390/toxins15090514] [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: 07/07/2023] [Revised: 08/16/2023] [Accepted: 08/18/2023] [Indexed: 09/28/2023] Open
Abstract
Since the early 2000s, studies of the evolution of venom within animals have rapidly expanded, offering new revelations on the origins and development of venom within various species. The venomous mammals represent excellent opportunities to study venom evolution due to the varying functional usages, the unusual distribution of venom across unrelated mammals and the diverse variety of delivery systems. A group of mammals that excellently represents a combination of these traits are the slow (Nycticebus spp.) and pygmy lorises (Xanthonycticebus spp.) of south-east Asia, which possess the only confirmed two-step venom system. These taxa also present one of the most intriguing mixes of toxic symptoms (cytotoxicity and immunotoxicity) and functional usages (intraspecific competition and ectoparasitic defence) seen in extant animals. We still lack many pieces of the puzzle in understanding how this venom system works, why it evolved what is involved in the venom system and what triggers the toxic components to work. Here, we review available data building upon a decade of research on this topic, focusing especially on why and how this venom system may have evolved. We discuss that research now suggests that venom in slow lorises has a sophisticated set of multiple uses in both intraspecific competition and the potential to disrupt the immune system of targets; we suggest that an exudate diet reveals several toxic plants consumed by slow and pygmy lorises that could be sequestered into their venom and which may help heal venomous bite wounds; we provide the most up-to-date visual model of the brachial gland exudate secretion protein (BGEsp); and we discuss research on a complement component 1r (C1R) protein in saliva that may solve the mystery of what activates the toxicity of slow and pygmy loris venom. We conclude that the slow and pygmy lorises possess amongst the most complex venom system in extant animals, and while we have still a lot more to understand about their venom system, we are close to a breakthrough, particularly with current technological advances.
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Affiliation(s)
- Leah Lucy Joscelyne Fitzpatrick
- Nocturnal Primate Research Group, Department of Social Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
- Centre for Functional Genomics, Department of Health and Life Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
| | - Rodrigo Ligabue-Braun
- Department of Pharmacosciences, Federal University of Health Sciences of Porto Alegre (UFCSPA), Avenida Sarmento Leite 245, Porto Alegre 90050-170, Brazil;
| | - K. Anne-Isola Nekaris
- Nocturnal Primate Research Group, Department of Social Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
- Centre for Functional Genomics, Department of Health and Life Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
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Paolino G, Di Nicola MR, Avella I, Mercuri SR. Venomous Bites, Stings and Poisoning by European Vertebrates as an Overlooked and Emerging Medical Problem: Recognition, Clinical Aspects and Therapeutic Management. Life (Basel) 2023; 13:1228. [PMID: 37374011 DOI: 10.3390/life13061228] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 05/17/2023] [Accepted: 05/20/2023] [Indexed: 06/29/2023] Open
Abstract
Europe presents a high number of venomous and poisonous animals able to elicit medically relevant symptoms in humans. However, since most of the accidents involving venomous or poisonous animals in Europe are unreported, their incidence and morbidity are severely overlooked. Here we provide an overview of the European vertebrate species of greatest toxicological interest, the clinical manifestations their toxins can cause, and their treatment. We report the clinical symptoms induced by envenomations and poisoning caused by reptiles, fishes, amphibians and mammals in Europe, ranging from mild, local symptoms (e.g., erythema, edema) to systemic and potentially deadly. The present work constitutes a tool for physicians to recognize envenomation/poisoning symptoms caused by the most medically relevant European vertebrates and to decide which approach is the most appropriate to treat them.
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Affiliation(s)
- Giovanni Paolino
- Unit of Dermatology and Cosmetology, I.R.C.C.S. San Raffaele Hospital, Via Olgettina 60, 20132 Milan, Italy
- Unit of Clinical Dermatology, Università Vita-Salute San Raffaele, Via Olgettina 60, 20132 Milan, Italy
| | - Matteo Riccardo Di Nicola
- Unit of Dermatology and Cosmetology, I.R.C.C.S. San Raffaele Hospital, Via Olgettina 60, 20132 Milan, Italy
- Asociación Herpetológica Española, Apartado de Correos 191, 28911 Leganés, Spain
| | - Ignazio Avella
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, 4485-661 Vairão, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, 4099-002 Porto, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, 4485-661 Vairão, Portugal
| | - Santo Raffaele Mercuri
- Unit of Dermatology and Cosmetology, I.R.C.C.S. San Raffaele Hospital, Via Olgettina 60, 20132 Milan, Italy
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Fitzpatrick LLJ, Nijman V, Ligabue-Braun R, Nekaris KAI. The Fast and the Furriest: Investigating the Rate of Selection on Mammalian Toxins. Toxins (Basel) 2022; 14:toxins14120842. [PMID: 36548740 PMCID: PMC9782207 DOI: 10.3390/toxins14120842] [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: 09/29/2022] [Revised: 11/25/2022] [Accepted: 11/26/2022] [Indexed: 12/03/2022] Open
Abstract
The evolution of venom and the selection pressures that act on toxins have been increasingly researched within toxinology in the last two decades, in part due to the exceptionally high rates of diversifying selection observed in animal toxins. In 2015, Sungar and Moran proposed the 'two-speed' model of toxin evolution linking evolutionary age of a group to the rates of selection acting on toxins but due to a lack of data, mammals were not included as less than 30 species of venomous mammal have been recorded, represented by elusive species which produce small amounts of venom. Due to advances in genomics and transcriptomics, the availability of toxin sequences from venomous mammals has been increasing. Using branch- and site-specific selection models, we present the rates of both episodic and pervasive selection acting upon venomous mammal toxins as a group for the first time. We identified seven toxin groups present within venomous mammals, representing Chiroptera, Eulipotyphla and Monotremata: KLK1, Plasminogen Activator, Desmallipins, PACAP, CRiSP, Kunitz Domain One and Kunitz Domain Two. All but one group (KLK1) was identified by our results to be evolving under both episodic and pervasive diversifying selection with four toxin groups having sites that were implicated in the fitness of the animal by TreeSAAP (Selection on Amino Acid Properties). Our results suggest that venomous mammal ecology, behaviour or genomic evolution are the main drivers of selection, although evolutionary age may still be a factor. Our conclusion from these results indicates that mammalian toxins are following the two-speed model of selection, evolving predominately under diversifying selection, fitting in with other younger venomous taxa like snakes and cone snails-with high amounts of accumulating mutations, leading to more novel adaptions in their toxins.
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Affiliation(s)
- Leah Lucy Joscelyne Fitzpatrick
- Nocturnal Primate Research Group, Department of Social Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
- Centre for Functional Genomics, Department of Health and Life Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
- Correspondence:
| | - Vincent Nijman
- Nocturnal Primate Research Group, Department of Social Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
- Centre for Functional Genomics, Department of Health and Life Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
| | - Rodrigo Ligabue-Braun
- Department of Pharmacosciences, Federal University of Health Sciences of Porto Alegre (UFCSPA), Avenida Sarmento Leite 245, Porto Alegre 90050-130, Brazil
| | - K. Anne-Isola Nekaris
- Nocturnal Primate Research Group, Department of Social Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
- Centre for Functional Genomics, Department of Health and Life Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
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Kowalski K, Marciniak P, Rychlik L. A new, widespread venomous mammal species: hemolytic activity of Sorex araneus venom is similar to that of Neomys fodiens venom. ZOOLOGICAL LETTERS 2022; 8:7. [PMID: 35672837 PMCID: PMC9172195 DOI: 10.1186/s40851-022-00191-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 03/08/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Venom production has evolved independently many times in the animal kingdom, although it is rare among mammals. Venomous shrews produce toxins in their salivary glands and use their venoms to hunt and store prey. Thus far, the toxicity and composition of shrew venoms have been studied only in two shrew species: the northern short-tailed shrew, Blarina brevicauda, and the Eurasian water shrew, Neomys fodiens. Venom of N. fodiens has potent paralytic activity which enables hunting and storing prey in a comatose state. Here, we assayed the hemolytic effects of extracts from salivary glands of N. fodiens and the common shrew, Sorex araneus, in erythrocytes of Pelophylax sp. frogs. We identified toxins in shrew venom by high-performance liquid chromatography coupled to tandem mass spectrometry. RESULTS Our results prove, confirming a suggestion made four centuries ago, that S. araneus is venomous. We also provide the first experimental evidence that shrew venoms produce potent hemolysis in frog erythrocytes. We found significant concentration-dependent effects of venoms of N. fodiens and S. araneus on hemolysis of red blood cells evaluated as hemoglobin release. Treatment of erythrocytes with N. fodiens venom at concentrations of 1.0 and 0.5 mg/ml and with S. araneus venom at concentration of 1.0 mg/ml caused an increased release of hemoglobin. Our findings confirm that hemolytic effects of N. fodiens venom are stronger than those produced by S. araneus venom. We identified four toxins in the venom of N. fodiens: proenkephalin, phospholipase A2 (PLA2), a disintegrin and metalloproteinase domain-containing protein (ADAM) and lysozyme C, as well as a non-toxic hyaluronidase. In the venom of S. araneus we found five toxins: proenkephalin, kallikrein 1-related peptidase, beta-defensin, ADAM and lysozyme C. PLA2 and ADAMs are likely to produce hemolysis in frog erythrocytes. CONCLUSIONS Our results clearly show that shrew venoms possess hemolytic action that may allow them to hunt larger prey. Since a member of the numerous genus Sorex is venomous, it is likely that venom production among shrews and other eulipotyphlans may be more widespread than it has previously been assumed.
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Affiliation(s)
- Krzysztof Kowalski
- Department of Vertebrate Zoology and Ecology, Institute of Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University, Lwowska 1, 87-100 Toruń, Poland
| | - Paweł Marciniak
- Department of Animal Physiology and Developmental Biology, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland
| | - Leszek Rychlik
- Department of Systematic Zoology, Institute of Environmental Biology, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland
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Barua A, Koludarov I, Mikheyev AS. Co-option of the same ancestral gene family gave rise to mammalian and reptilian toxins. BMC Biol 2021; 19:268. [PMID: 34949191 PMCID: PMC8705180 DOI: 10.1186/s12915-021-01191-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 11/11/2021] [Indexed: 12/03/2022] Open
Abstract
Background Evolution can occur with surprising predictability when organisms face similar ecological challenges. For most traits, it is difficult to ascertain whether this occurs due to constraints imposed by the number of possible phenotypic solutions or because of parallel responses by shared genetic and regulatory architecture. Exceptionally, oral venoms are a tractable model of trait evolution, being largely composed of proteinaceous toxins that have evolved in many tetrapods, ranging from reptiles to mammals. Given the diversity of venomous lineages, they are believed to have evolved convergently, even though biochemically similar toxins occur in all taxa. Results Here, we investigate whether ancestral genes harbouring similar biochemical activity may have primed venom evolution, focusing on the origins of kallikrein-like serine proteases that form the core of most vertebrate oral venoms. Using syntenic relationships between genes flanking known toxins, we traced the origin of kallikreins to a single locus containing one or more nearby paralogous kallikrein-like clusters. Additionally, phylogenetic analysis of vertebrate serine proteases revealed that kallikrein-like toxins in mammals and reptiles are genetically distinct from non-toxin ones. Conclusions Given the shared regulatory and genetic machinery, these findings suggest that tetrapod venoms evolved by co-option of proteins that were likely already present in saliva. We term such genes ‘toxipotent’—in the case of salivary kallikreins they already had potent vasodilatory activity that was weaponized by venomous lineages. Furthermore, the ubiquitous distribution of kallikreins across vertebrates suggests that the evolution of envenomation may be more common than previously recognized, blurring the line between venomous and non-venomous animals. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01191-1.
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Affiliation(s)
- Agneesh Barua
- Ecology and Evolution Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan.
| | - Ivan Koludarov
- Animal Venomics Group, Justus Leibig University, Giessen, Germany
| | - Alexander S Mikheyev
- Research School of Biology, Australian National University, Canberra, ACT, Australia.
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Vonk FJ, Bittenbinder MA, Kerkkamp HMI, Grashof DGB, Archer JP, Afonso S, Richardson MK, Kool J, van der Meijden A. A non-lethal method for studying scorpion venom gland transcriptomes, with a review of potentially suitable taxa to which it can be applied. PLoS One 2021; 16:e0258712. [PMID: 34793470 PMCID: PMC8601437 DOI: 10.1371/journal.pone.0258712] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 10/05/2021] [Indexed: 12/24/2022] Open
Abstract
Scorpion venoms are mixtures of proteins, peptides and small molecular compounds with high specificity for ion channels and are therefore considered to be promising candidates in the venoms-to-drugs pipeline. Transcriptomes are important tools for studying the composition and expression of scorpion venom. Unfortunately, studying the venom gland transcriptome traditionally requires sacrificing the animal and therefore is always a single snapshot in time. This paper describes a new way of generating a scorpion venom gland transcriptome without sacrificing the animal, thereby allowing the study of the transcriptome at various time points within a single individual. By comparing these venom-derived transcriptomes to the traditional whole-telson transcriptomes we show that the relative expression levels of the major toxin classes are similar. We further performed a multi-day extraction using our proposed method to show the possibility of doing a multiple time point transcriptome analysis. This allows for the study of patterns of toxin gene activation over time a single individual, and allows assessment of the effects of diet, season and other factors that are known or likely to influence intraindividual venom composition. We discuss the gland characteristics that may allow this method to be successful in scorpions and provide a review of other venomous taxa to which this method may potentially be successfully applied.
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Affiliation(s)
- Freek J. Vonk
- Naturalis Biodiversity Center, Leiden, The Netherlands
- Faculty of Sciences, Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Animal Science and Health Cluster, Institute of Biology Leiden, Leiden University, Leiden, The Netherlands
| | - Mátyás A. Bittenbinder
- Naturalis Biodiversity Center, Leiden, The Netherlands
- Faculty of Sciences, Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Harald M. I. Kerkkamp
- Naturalis Biodiversity Center, Leiden, The Netherlands
- Animal Science and Health Cluster, Institute of Biology Leiden, Leiden University, Leiden, The Netherlands
| | | | - John P. Archer
- CIBIO-InBIO, Biopolis, Universidade do Porto, Porto, Portugal
| | - Sandra Afonso
- CIBIO-InBIO, Biopolis, Universidade do Porto, Porto, Portugal
| | - Michael K. Richardson
- Animal Science and Health Cluster, Institute of Biology Leiden, Leiden University, Leiden, The Netherlands
| | - Jeroen Kool
- Faculty of Sciences, Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
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Trim CM, Byrne LJ, Trim SA. Utilisation of compounds from venoms in drug discovery. PROGRESS IN MEDICINAL CHEMISTRY 2021; 60:1-66. [PMID: 34147202 DOI: 10.1016/bs.pmch.2021.01.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Difficult drug targets are becoming the normal course of business in drug discovery, sometimes due to large interacting surfaces or only small differences in selectivity regions. For these, a different approach is merited: compounds lying somewhere between the small molecule and the large antibody in terms of many properties including stability, biodistribution and pharmacokinetics. Venoms have evolved over millions of years to be complex mixtures of stable molecules derived from other somatic molecules, the stability comes from the pressure to be ready for delivery at a moment's notice. Snakes, spiders, scorpions, jellyfish, wasps, fish and even mammals have evolved independent venom systems with complex mixtures in their chemical arsenal. These venom-derived molecules have been proven to be useful tools, such as for the development of antihypotensive angiotensin converting enzyme (ACE) inhibitors and have also made successful drugs such as Byetta® (Exenatide), Integrilin® (Eptifibatide) and Echistatin. Only a small percentage of the available chemical space from venoms has been investigated so far and this is growing. In a new era of biological therapeutics, venom peptides present opportunities for larger target engagement surface with greater stability than antibodies or human peptides. There are challenges for oral absorption and target engagement, but there are venom structures that overcome these and thus provide substrate for engineering novel molecules that combine all desired properties. Venom researchers are characterising new venoms, species, and functions all the time, these provide great substrate for solving the challenges presented by today's difficult targets.
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Affiliation(s)
- Carol M Trim
- Faculty of Science, Engineering and Social Sciences, Natural and Applied Sciences, School of Psychology and Life Sciences, Canterbury Christ Church University, Canterbury, Kent, United Kingdom
| | - Lee J Byrne
- Faculty of Science, Engineering and Social Sciences, Natural and Applied Sciences, School of Psychology and Life Sciences, Canterbury Christ Church University, Canterbury, Kent, United Kingdom
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Venom Use in Eulipotyphlans: An Evolutionary and Ecological Approach. Toxins (Basel) 2021; 13:toxins13030231. [PMID: 33810196 PMCID: PMC8004749 DOI: 10.3390/toxins13030231] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 03/15/2021] [Accepted: 03/18/2021] [Indexed: 11/16/2022] Open
Abstract
Venomousness is a complex functional trait that has evolved independently many times in the animal kingdom, although it is rare among mammals. Intriguingly, most venomous mammal species belong to Eulipotyphla (solenodons, shrews). This fact may be linked to their high metabolic rate and a nearly continuous demand of nutritious food, and thus it relates the venom functions to facilitation of their efficient foraging. While mammalian venoms have been investigated using biochemical and molecular assays, studies of their ecological functions have been neglected for a long time. Therefore, we provide here an overview of what is currently known about eulipotyphlan venoms, followed by a discussion of how these venoms might have evolved under ecological pressures related to food acquisition, ecological interactions, and defense and protection. We delineate six mutually nonexclusive functions of venom (prey hunting, food hoarding, food digestion, reducing intra- and interspecific conflicts, avoidance of predation risk, weapons in intraspecific competition) and a number of different subfunctions for eulipotyphlans, among which some are so far only hypothetical while others have some empirical confirmation. The functions resulting from the need for food acquisition seem to be the most important for solenodons and especially for shrews. We also present several hypotheses explaining why, despite so many potentially beneficial functions, venomousness is rare even among eulipotyphlans. The tentativeness of many of the arguments presented in this review highlights our main conclusion, i.e., insights regarding the functions of eulipotyphlan venoms merit additional study.
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