Transcriptomic profiling and the first spatial expression analysis of candidate genes in the salivary gland of the East Asian medicinal leech, Hirudo nipponia
Research article published in Developmental and comparative immunology (2024)
Abstract
Hirudo nipponia, a blood-sucking leech native to East Asia, possesses a rich repertoire of active ingredients in its saliva, showcasing significant medical potential due to its anticoagulant, anti-inflammatory, and antibacterial effects against human diseases. Despite previous studies on the transcriptomic and proteomic characteristics of leech saliva, which have identified medicinal compounds, our knowledge of tissue-specific transcriptomes and their spatial expression patterns remains incomplete. In this study, we conducted an extensive transcriptomic profiling of the salivary gland tissue in H. nipponia based on de novo assemblies of tissue-specific transcriptomes from the salivary gland, teeth, and general head region. Through gene ontology (GO) analysis and hierarchical clustering, we discovered a novel set of anti-coagulant factors-i.e., Hni-Antistasin, Hni-Ghilanten, Hni-Bdellin, Hni-Hirudin-as well as a previously unrecognized immune-related gene, Hni-GLIPR1 and uncharacterized salivary gland specific transcripts. By employing in situ hybridization, we provided the first visualization of gene expression sites within the salivary gland of H. nipponia. Our findings expand on our understanding of transcripts specifically expressed in the salivary gland of blood-sucking leeches, offering valuable resources for the exploration of previously unidentified substances with medicinal applications.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Summary
Hirudo nipponia, a blood-sucking leech native to East Asia, has a rich repertoire of active ingredients in its saliva, with significant medical potential due to its anticoagulant, anti-inflammatory, and antibacterial effects against human diseases.
Why This Matters for Hirudotherapy
This study performed de novo transcriptomic profiling of salivary gland tissue in the East Asian medicinal leech Hirudo nipponia, assembling tissue-specific transcriptomes from salivary gland, teeth, and head regions, and identified anticoagulant factors (Hni-Antistasin, Hni-Ghilanten, Hni-Bdellin, Hni-Hirudin), the immune-related gene Hni-GLIPR1, and uncharacterized salivary gland-specific transcripts, with gene expression sites visualized via in situ hybridization. This work is centrally relevant to hirudotherapy and the leech salivary secretome, as it molecularly catalogs the bioactive compounds—including anticoagulants with recognized therapeutic relevance—that underpin medicinal leech applications and highlights previously unrecognized candidate substances for pharmacological exploration. However, the study provides transcriptomic and spatial gene expression data only, without functional validation of bioactivity, clinical outcomes, or demonstration of therapeutic efficacy; the medicinal significance of the newly described transcripts remains to be established experimentally.
Citation
Transcriptomic profiling and the first spatial expression analysis of candidate genes in the salivary gland of the East Asian medicinal leech, Hirudo nipponia.
Kim J et al. · Developmental and comparative immunology, 2024
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