Although it is well known that wound healing proceeds incredibly quickly in urodele amphibians, such as newts and salamanders, little is known about skin-wound healing, and no bioactive/effector substance that contributes to wound healing has been identified from these animals. As a step toward understanding salamander wound healing and skin regeneration, a potential wound-healing-promoting peptide (tylotoin; KCVRQNNKRVCK) was identified from salamander skin of Tylototriton verrucosus. It shows comparable wound-healing-promoting ability (EC50=11.14 ?g/ml) with epidermal growth factor (EGF; NSDSECPLSHDGYCLHDGVCMYIEALDKYACNCVVGYIGERCQYRDLKWWELR) in a murine model of full-thickness dermal wound. Tylotoin directly enhances the motility and proliferation of keratinocytes, vascular endothelial cells, and fibroblasts, resulting in accelerated reepithelialization and granulation tissue formation in the wound site. Tylotoin also promotes the release of transforming growth factor ?1 (TGF-?1) and interleukin 6 (IL-6), which are essential in the wound healing response. Gene-encoded tylotoin secreted in salamander skin is possibly an effector molecule for skin wound healing. This study may facilitate understanding of the cellular and molecular events that underlie quick wound healing in salamanders.-Mu, L., Tang, J., Liu, H., Shen, C., Rong, M., Zhang, Z., Lai, R. A potential wound-healing-promoting peptide from salamander skin.
26RFa is one of neuroendocrine peptide groups in the RFamide peptide family containing conserved Arg-Phe/Tyr-NH2 motif at their C-terminus. They exert multiple biological functions in vertebrates. A novel 26RFa peptide (TC26RFa) with unique structure is identified from the tree shrew of Tupaia belangeri chinensis in the present study. In structure, different from other 26RFa peptides containing conserved Phe-Arg-Phe-NH2 motif at their C-terminus, there is a Phe-Arg-Tyr-NH2 C-terminus in TC26RFa. It has been found that TC26RFa of intraperitoneal injection exerts strong analgesic activities in several mice models including acetic acid-induced abdominal writhing, formalin-induced paw licking, and thermal pain-induced tail withdrawal. It shows comparable analgesic ability with morphine. In addition, this peptide has been found to inhibit inflammatory factor secretion (including tumor necrosis factor-?, interleukin-6, and interleukin-1?) induced by lipopolysaccharides (LPS). Furthermore, it stimulates secretion of the anti-inflammatory factor, interleukin-10. In addition to the identification of a novel 26RFa peptide from tree shrew, a new type of function (anti-inflammation) involved in 26RFa peptide is discovered.
Vasotab TY is a KGD (Lys-Gly-Asp)-containing peptide identified from salivary glands of the horsefly of Tabanus yao. We have previously reported that vasotab TY showed a strong vasodilator activity. In the present study, vasotab TY was found to inhibit platelet aggregation effectively. It completely inhibited platelet aggregation induced by adenosine diphosphate (ADP) at the concentration of 9.6?g/ml. Vasotab TY significantly reduced thrombus weight in rat arteriovenous shunt model and inhibited thrombosis in carrageenan-induced mouse tail thrombosis model in vivo. Vasotab TY competitively bound to glycoprotein IIb/IIIa (GPIIb/IIIa) with eptifibatide, a well-known KGD-containing cyclic heptapeptide containing high specificity and high affinity for GPIIb/IIIa, suggesting that it is an antagonist of the fibrinogen receptor GPIIb/IIIa on the surface of platelet. The KGD motif in vasotab TY may facilitate the binding of it to GPIIb/IIIa. Vasotab TY showed a half-life of more than 1h in vivo. It showed little side effects including little bleeding, no hemolytic activity on human blood red cells and no cytotoxicity on human keratinocyte and THP-1 cells. Combined its vasodilator and platelet inhibitory functions, vasotab TY might be an excellent candidate for the development of clinical anti-thrombosis medicines.
Cutaneous wound healing is a dynamic, complex, and well-organized process that requires the orchestration of many different cell types and cellular processes. Transforming growth factor ?1 is an important factor that plays a key role during wound healing. Amphibian skin has been proven to possess excellent wound healing ability, whilst no bioactive substrate related to it has ever been identified. Here, a potential wound healing-promoting peptide (AH90, ATAWDFGPHGLLPIRPIRIRPLCG) was identified from the frog skin of Odorrana grahami. It showed potential wound healing-promoting activity in a murine model with full thickness dermal wound. AH90 promoted release of transforming growth factor ?1 through activation of nuclear factor-?B and c-Jun NH2-terminal kinase mitogen-activated protein kinases signaling pathways, while inhibitors of nuclear factor-?B and c-Jun NH2-terminal kinase inhibited the process. In addition, the effects of AH90 on Smads family proteins, key regulators in transforming growth factor ?1 signaling pathways, could also be inhibited by transforming growth factor ?1 antibody. Altogether, this indicated that AH90 promoted wound healing by inducing the release of transforming growth factor ?1. This current study may facilitate the understanding of effective factors involved in the wound repair of amphibians and the underlying mechanisms as well. Considering its favorable traits as a small peptide that greatly promoting generation of endogenous wound healing agents (transforming growth factor ?1) without mitogenic effects, AH90 might be an excellent template for the future development of novel wound-healing agents.
Antimicrobial peptides have been widely identified from amphibian skins except salamanders. A novel antimicrobial peptide (CFBD) was isolated and characterized from skin secretions of the salamander, Cynops fudingensis. The cDNA encoding CFBD precursor was cloned from the skin cDNA library of C. fudingensis. The precursor was composed of three domains: signal peptide of 17 residues, mature peptide of 41 residues and intervening propeptide of 3 residues. There are six cysteines in the sequence of mature CFBD peptide, which possibly form three disulfide-bridges. CFBD showed antimicrobial activities against Staphylococcus aureus, Bacillus subtilis, Candida albicans and Escherichia coli. This peptide could be classified into family of ?-defensin based on its seqeuence similarity with ?-defensins from other vertebrates. Evolution analysis indicated that CFBD was close to fish ?-defensin. As far as we know, CFBD is the first ?-defensin antimicrobial peptide from salamanders.
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