Cath-DM-NT, a peptide derived from the skin of Duttaphrynus melanostictus, shows dual lectin-like and antioxidant activity

Animal-derived peptides from Traditional Chinese medicines: medicinal potential, mechanisms, and prospects

ETHNOPHARMACOLOGICAL RELEVANCE

Animal-derived traditional Chinese medicines have a long-standing history in Chinese medicine, which exhibit unique efficacy due to similar structure and function with human tissue. As the major types of constituents that accounted for a relatively high proportion of animal-derived TCMs, peptides with molecular weight between 100 Da and hundreds of thousands of kDa have caught wide attention due to their outstanding bioavailability and excellent specificity.

AIM OF THE STUDY

This review aims to comprehensively delve into the up-to-date research progress in their pharmacology, mechanism, sequence composition, and therapeutic application, laying a solid foundation for future clinical treatment and scientific research.

MATERIALS AND METHODS

Relevant information on the peptides from animal-derived TCMs was collected from scientific literature databases including PubMed, CNKI, literature sources (Ph.D. and M.Sc. dissertations), and Web of Science by using the keywords "Peptides", "Animal", and "TCMs" for gradual screening in the past 30 years.

RESULTS

To date, the peptides from 27 kinds of animal-derived TCMs have been systematically combed. Their pharmacological activity and underlying mechanisms on multiple systems (nervous, circulatory, skeletal, and immune), as well as anti-tumor, antioxidative, and antimicrobial effects, have been sorted out. Besides, the potential safety issues and deficiencies (low bioavailability, imperfect quality management, and toxicity of raw materials) have also been pointed out.

CONCLUSIONS

Comprehensive analysis showed that low development and resource waste accompanied by the inadequate report about the pharmacological activity of most peptides from animal-derived TCMs make it have good research prospects. Although a breakthrough in the field of healthcare products has been made, the development potential for clinical products that bring surprising turnaround will be obtained if the above-mentioned confusions and current needs (improve identification technology and design reasonable dosage forms) are implemented.

Characterization of the first antimicrobial peptide from Sea Seal with potent therapeutic effect in septic mice

Marine organisms are a valuable source of natural bioactive substances, and an increasing number of marine antimicrobial peptides as the potential alternative to antibiotics are being developed. Nonetheless, antimicrobial peptides from Antarctic mammals have not been reported heretofore. In this context, we identified a Cathelicidin antimicrobial peptide, Cath-LW (RLRDLIRRGRQKIGRRINRLGRRIQDILKNLQPGKVS), from the whole-genome database of Leptonychotes weddellii, an Antarctic mammal. Cath-LW was characterized to exhibit a typical α-helix structure and broad-spectrum antimicrobial activity. Furthermore, Cath-LW was found to exert its antibacterial effect by destroying cytomembrane, binding to bacterial genome, and inhibiting DNA function. Additionally, Cath-LW could neutralize lipopolysaccharide (LPS) and inhibit LPS-induced inflammatory responses. Interestingly, Cath-LW also showed anticoagulant activity and suppressed FeCl3-induced carotid thrombosis in mice. Finally, in septic mice, Cath-LW was demonstrated to improve the survival rate by effectively alleviating organ inflammation and damage, as well as thrombus formation. These findings not only deepen our understanding of the survival strategies of L. weddellii against microbial infections but also provide a crucial template for developing a novel multifunctional anti-sepsis drug.

Cathelicidin-HG alleviates psoriasis by targeting glycoprotein VI to inhibit platelet-neutrophil complexes formation

Psoriasis, a chronic inflammatory skin disorder, is characterized by a complex interplay among immune cells. Although the specific mechanisms of platelet involvement in psoriasis are not fully elucidated, platelet activation is considered a major pathogenic factor. In this study, we investigated the role of Cathelicidin-HG (Cath-HG), a peptide derived from Hylarana guentheri skin that exhibits potent inhibitory activity against platelet glycoprotein VI (GPVI), in an imiquimod-induced psoriasis mouse model. Our experimental findings demonstrated that Cath-HG significantly alleviates psoriasis symptoms, reduces platelet-neutrophil complexes (PNCs) formation, and attenuates neutrophil activation at lesion sites. In vitro studies confirmed that Cath-HG inhibits collagen-induced platelet activation via GPVI, thereby disrupting PNCs formation and suppressing subsequent inflammatory responses. These findings not only establish GPVI as a key regulator of PNC-mediated inflammation in psoriasis but also identify Cath-HG as a promising therapeutic candidate. This study provides a novel mechanistic insight into platelet-neutrophil interactions in psoriasis and highlights the potential of GPVI as a therapeutic target for innovative psoriasis treatments.

Cath-HG improves the survival rates and symptoms in LPS-induced septic mice due to its multifunctional properties

The clinical syndrome of sepsis arises from severe infection, triggering an abnormal immune response that can lead to multiple organ dysfunction and ultimately the death of the host. Current therapies for sepsis are often limited in efficacy and fail to target the complex interplay of infection, inflammation and coagulation, leading to high mortality rates, which underscores the urgent need for novel therapeutics to combat sepsis. We previously identified Cath-HG, a compound capable of alleviating platelet dysfunction by suppressing GPVI-mediated platelet activation, thereby improving the survival of septic mice subjected to cecal ligation and puncture. Here, we further explored the antimicrobial, anti-inflammatory, LPS-neutralizing and anticoagulant properties of Cath-HG, as well as its protective effects in LPS-induced septic mice. Our results demonstrated that Cath-HG can bind to LPS, aggregate bacteria, and disrupt bacterial cell membranes, subsequently resulting in microbial death. Unlike most other Cathelicidins, Cath-HG displayed anticoagulation properties by regulating the enzymes plasmin, thrombin, β-tryptase, chymase and tissue plasminogen activator. In septic mice, Cath-HG provided protection against sepsis induced by LPS injection and exhibited bactericidal killing, LPS neutralization and inhibition of coagulation and MAPK signal transduction. Furthermore, Cath-HG obviously reduced the expression of pro-inflammatory cytokines and improved the pathological manifestations of tissue injury across multiple organs. Thus, Cath-HG emerges as a promising drug candidate for protecting against sepsis.

A non-bactericidal cathelicidin with antioxidant properties ameliorates UVB-induced mouse skin photoaging via intracellular ROS scavenging and Keap1/Nrf2 pathway activation

Cathelicidins, a category of critical host defense molecules in vertebrates, have been extensively studied for their bactericidal functions, but little is known about their non-bactericidal properties. Herein, a novel cathelicidin peptide (Atonp2) was identified from the plateau frog Nanorana ventripunctata. It did not exhibit bactericidal activity but showed significant therapeutic effects in chronic UVB radiation-induced mouse skin photoaging through inhibiting thickening, pyroptosis and inflammation in the epidermis, while inhibiting cellular senescence, collagen fibre breakage and type Ⅰ collagen reduction in the dermis. Further studies indicated that Atonp2 effectively scavenged UVB-induced intracellular ROS via tyrosines at positions 9 and 10, while activating the Keap1/Nrf2 pathway to protect epidermal keratinocytes against UVB radiation, which in turn indirectly reversed the senescence and collagen degradation of dermal fibroblasts, thereby ameliorating UVB-induced skin photoaging. As such, this study identified a non-bactericidal cathelicidin peptide with potent antioxidant functions, highlighting its potential to treat and prevent skin photoaging.