Diversity of hirudin and hirudin-like factor genes in the North-African medicinal leech, Hirudo troctina
Research article published in Parasitology research (2024)
Abstract
Medicinal leeches of the genus Hirudo inhabit large areas of the Palaearctic realm. The distribution range of Hirudo troctina includes the southern Iberian peninsula and the northwestern regions of Africa. H. troctina is used for medical purposes, but only very little is known about the components of its salivary gland secretion. Hirudins, bivalent inhibitors of thrombin, are probably the best known leech-derived bioactive factors. Hirudin-like factors (HLFs) represent another class of salivary gland components that share characteristic genetic and structural markers with hirudins. Hirudin is not a single entity but exists in at least four different variants. However, there are differences among the European members of the genus Hirudo with respect to the actual number of hirudin and HLF genes that are present within their genomes. Here, we describe the identification and molecular cloning of 11 genes that encode for putative hirudin and HLF variants in H. troctina. Three of the genes consist of exons and introns that originate from different "archetype" genes and are likely the result of recombination events. The diversity of hirudin and HLF genes in H. troctina surpasses that of all other European members of the genus Hirudo. The putative hirudin variants and representatives of the HLFs of H. troctina were expressed as recombinant proteins, purified and functionally characterized for their thrombin-inhibiting potencies. Phylogenetic analyses based on hirudin and HLF gene sequences of the leech genera Hirudo, Hirudinaria, and Whitmania supported the hypothesis that hirudins and HLFs diverged early in leech evolution.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Summary
Medicinal leeches of the genus Hirudo inhabit large areas of the Palaearctic realm. The distribution range of Hirudo troctina includes the southern Iberian peninsula and the northwestern regions of Africa.
Why This Matters for Hirudotherapy
This study identified and molecularly cloned 11 genes encoding putative hirudin and hirudin-like factor (HLF) variants in Hirudo troctina, a medicinal leech whose distribution range includes the southern Iberian peninsula and northwestern Africa. Recombinant proteins were expressed, purified, and functionally characterized for thrombin-inhibiting potencies, and phylogenetic analyses examined the evolutionary relationships of hirudin and HLF genes across the leech genera Hirudo, Hirudinaria, and Whitmania. This work is relevant to hirudotherapy because hirudins are among the best-characterized bioactive anticoagulants in leech salivary secretions, and documenting the genetic diversity of these thrombin inhibitors across Hirudo species may contribute to understanding variation in salivary composition among leeches used clinically. However, the study's relevance is primarily molecular and phylogenetic rather than clinical: it reports in vitro characterization of recombinant proteins and gene-level findings, not therapeutic outcomes or direct hirudotherapy applications.
Citation
Diversity of hirudin and hirudin-like factor genes in the North-African medicinal leech, Hirudo troctina.
Ahmed R, Abilov A, Müller C · Parasitology research, 2024
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