Characterization of the natural peptidome of four leeches by integrated proteogenomics and pseudotargeted peptidomics
Basic science / proteomics published in Anal Bioanal Chem (2023)
Abstract
Animal-derived drugs are an indispensable part of folk medicine worldwide. However, their chemical constituents are poorly approached, which leads to the low level of the quality standard system of animal-derived drugs and further causes a chaotic market. Natural peptides are ubiquitous throughout the organism, especially in animal-derived drugs. Thus, in this study, we used multi-source leeches, including Hirudo nipponica (HN), Whitmania pigra (WP), Whitmania acranulata (WA), and Poecilobdella manillensis (PM), as a model. A strategy integrating proteogenomics and novel pseudotargeted peptidomics was developed to characterize the natural peptide phenotype and screen for signature peptides of four leech species. First, natural peptides were sequenced against an in-house annotated protein database of closely related species constructed from RNA-seq data from the Sequence Read Archive (SRA) website, which is an open-sourced public archive resource. Second, a novel pseudotargeted peptidomics integrating peptide ion pair extraction and retention time transfer was established to achieve high coverage and quantitative accuracy of the natural peptides and to screen for signature peptides for species authentication. In all, 2323 natural peptides were identified from four leech species whose databases were poorly annotated. The strategy was shown to significantly improve peptide identification. In addition, 36 of 167 differential peptides screened by pseudotargeted proteomics were identified, and about one-third of them came from the leucine-rich repeat domain (LRR) proteins, which are widely distributed in organisms. Furthermore, six signature peptides were screened with good specificity and stability, and four of them were validated by synthetic standards. Finally, a dynamic multiple reaction monitoring (dMRM) method based on these signature peptides was established and revealed that one-half of the commercial samples and all of the Tongxinluo capsules were derived from WP. All in all, the strategy developed in this study was effective for natural peptide characterization and signature peptide screening, which could also be applied to other animal-derived drugs, especially for modelless species that are less studied in protein database annotation.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Summary
Integrated proteogenomics + pseudotargeted peptidomics analysis of four leech species (Hirudo nipponica, Whitmania pigra, Whitmania acranulata, Poecilobdella manillensis). Identifies 2323 natural peptides and six signature peptides for species authentication.
Why This Matters for Hirudotherapy
This study characterized the natural peptidome of four leech species—Hirudo nipponia, Whitmania pigra, Whitmania acranulata, and Poecilobdella manillensis—using an integrated proteogenomics and pseudotargeted peptidomics strategy, identifying 2,323 natural peptides and screening six signature peptides for species authentication, of which four were validated by synthetic standards. A dMRM method based on these signature peptides revealed that one-half of commercial samples and all Tongxinluo capsules were derived from W. pigra. For ASH's domain, this work is relevant to quality control and authentication of leech-derived medicinal products, addressing misidentification in the animal-derived drug market. However, the study focuses on peptide profiling for authentication rather than therapeutic efficacy or bioactive compound characterization, and its direct relevance to live hirudotherapy is limited.
Citation
Characterization of the natural peptidome of four leeches by integrated proteogenomics and pseudotargeted peptidomics.
Liu X et al. · Analytical and bioanalytical chemistry, 2023
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