The Origin and Evolution of Antistasin-like Proteins in Leeches (Hirudinida, Clitellata)
Evolutionary genomics published in Genome Biology and Evolution (2021)
Abstract
Bloodfeeding is employed by many parasitic animals and requires specific innovations for efficient feeding. Some of these innovations are molecular features that are related to the inhibition of hemostasis. For example, bloodfeeding insects, bats, and leeches release proteins with anticoagulatory activity through their salivary secretions. The antistasin-like protein family, composed of serine protease inhibitors with one or more antistasin-like domains, is tightly linked to inhibition of hemostasis in leeches. However, this protein family has been recorded also in non-bloodfeeding invertebrates, such as cnidarians, mollusks, polychaetes, and oligochaetes. The present study aims to 1) root the antistasin-like gene tree and delimit the major orthologous groups, 2) identify potential independent origins of salivary proteins secreted by leeches, and 3) identify major changes in domain and/or motif structure within each orthologous group. Five clades containing leech antistasin-like proteins are distinguishable through rigorous phylogenetic analyses based on nine new transcriptomes and a diverse set of comparative data: the trypsin + leukocyte elastase inhibitors clade, the antistasin clade, the therostasin clade, and two additional, unnamed clades. The antistasin-like gene tree supports multiple origins of leech antistasin-like proteins due to the presence of both leech and non-leech sequences in one of the unnamed clades, but a single origin of factor Xa and trypsin + leukocyte elastase inhibitors. This is further supported by three sequence motifs that are exclusive to antistasins, the trypsin + leukocyte elastase inhibitor clade, and the therostasin clade, respectively. We discuss the implications of our findings for the evolution of this diverse family of leech anticoagulants.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Summary
Phylogenetic analysis of antistasin-like serine protease inhibitors across leeches and other invertebrates identified five clades, supporting multiple independent origins of salivary antistasin-like proteins but a single origin of factor Xa and trypsin/elastase inhibitors.
Why This Matters for Hirudotherapy
This study reconstructed the evolutionary history of antistasin-like proteins—a family of serine protease inhibitors linked to hemostasis inhibition in leech salivary secretions—using nine new transcriptomes and broad comparative sequence data. Phylogenetic analyses identified five clades of leech antistasin-like proteins (including the antistasin, therostasin, and trypsin + leukocyte elastase inhibitor clades), supporting multiple independent origins of leech antistasin-like proteins but a single origin for factor Xa and trypsin + leukocyte elastase inhibitors. The work informs the evolutionary context of leech-derived anticoagulant proteins tied to bloodfeeding. However, the study is purely phylogenetic and bioinformatic, providing no functional assays, clinical data, or characterization of specific therapeutic candidates.
Citation
Reference (Vancouver style)
Iwama RE, Tessler M, Siddall ME, Kvist S. The Origin and Evolution of Antistasin-like Proteins in Leeches (Hirudinida, Clitellata). Genome Biol Evol. 2021;13(1). doi:10.1093/gbe/evaa242. PMID: 33527140
Bibliographic details (authors, volume, pages, DOI) are taken from the PubMed record.
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