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Background: Active peptides play a vital role in the development of new drugs and the identification and discovery of drug targets. As the first reported native peptide homodimer with pro‐regenerative potency, OA‐GP11d could potentially be used as a novel molecular probe to help elucidate the molecular mechanism of skin wound repair and provide new drug targets. Methods: Bioinformatics analysis and luciferase assay were adopted to determine microRNAs (miRNAs) and its target. The prohealing potency of the miRNA was determined by MTS and a Transwell experiment against mouse macrophages. Enzyme‐linked immunosorbent assay, realtime polymerase chain reaction, and western blotting were performed to explore the molecular mechanisms. Results: In this study, OA‐GP11d was shown to induce Mus musculus microRNA‐186‐5p (mmu‐miR‐186‐5p) down‐regulation. Results showed that miR‐186‐5p had a negative effect on macrophage migration and proliferation as well as a targeted and negative effect on TGF‐β type II receptor (TGFβR2) expression and an inhibitory effect on activation of the downstream SMAD family member 2 (Smad2) and protein‐p38 kinase signaling pathways. Importantly, delivery of a miR‐186‐5p mimic delayed skin wound healing in mice. Conclusion: miR‐186‐5p regulated macrophage migration and proliferation to delay wound healing through the TGFβR2/Smad2/p38 molecular axes, thus providing a promising new pro‐repair drug target. [ABSTRACT FROM AUTHOR]

Background: Chronic actinic dermatitis (CAD) is an immune‐mediated photodermatosis characterized by a high eosinophil count and total immunoglobulin E (IgE) in the peripheral blood of patients. At present, however, the reasons for their elevation remain unclear. Objective: The current study aimed to detect changes in inflammatory cytokines in CAD and explore their role in this disease. Methods: Enzyme‐linked immunosorbent assay and Luminex assay were conducted to measure inflammatory factor levels. Immunohistochemical analysis and quantitative real‐time polymerase chain reaction were performed to evaluate the expression levels of interleukin‐36γ (IL‐36γ), IL‐8, chemokine (C‐C motif) ligand 17 (CCL17), and CCL18. CCK8 kits were used to assess cell proliferation. Immunofluorescence was used to detect nuclear factor κB (NF‐κB) p65 nuclear translocation. Western blot analysis was performed to detect the protein expression level of phosphorylated NF‐κB (p‐NF‐κB) p65. Hematoxylin and eosin and Masson trichrome staining were applied to observe histological changes in a chronic photo‐damaged mouse model. Results: Eosinophils, total IgE, IL‐36γ, IL‐8, tumor necrosis factor α, CCL17, and CCL18 were elevated in CAD. Of note, IL‐36γ promoted the proliferation of eosinophilic cells (EOL‐1) and the production of IgE in peripheral blood mononuclear cells. IL‐36γ also promoted the production of IL‐8 and CCL18 in immortalized human keratinocytes (HaCaT cells), while ultraviolet radiation (UVR)‐induced IL‐36γ via activation of the NF‐κB signaling pathway. Conclusions: IL‐36γ was involved in the pathogenesis of CAD and UVR contributed to the production of IL‐36γ, which may provide a novel therapeutic target for CAD. [ABSTRACT FROM AUTHOR]

In clinical trials, the healing of wounds remains a substantial physiological and financial incumbrance on patients. Therefore, the development of new drugs that can accelerate wound healing is vital. Based on genomic methods, we identified a new peptide (RL-RL10) with the amino acid sequence 'RLFKCWKKDS' from the skin of an amphibian frog species (Rana limnocharis). RL-RL10 promoted wound healing of human keratinocytes (HaCaT) in a concentration-dependent manner. RL-RL10 also had an effect on the migration and proliferation of HaCaT cells and promoted healing of a full-thickness wound in mice in a dose-dependent manner. In conclusion, we discovered RL-RL10 that promoted healing activity of cellular and animal wounds, thus providing a new peptide template for the development of novel wound-repairing drugs. [ABSTRACT FROM AUTHOR]

Amphibian skin is known to secrete gene-encoded antioxidant peptides of small molecular weight, which play important roles in host defense. However, recognition of such peptides is still in its infancy. Here, we discovered a novel gene-encoded antioxidant peptide (named OM-GF17) from skin secretions of amphibian species, Odorrana margaretae. Produced by the post-translational processing of a 61-residue prepropeptide, the amino acid sequence of OM-GF17 was 'GFFKWHPRCGEEHSMWT', with a molecular mass of 2135.7 Da. Functional analysis revealed that OM-GF17 scavenged ABTS+, DPPH, NO and decreased iron oxidation. Our results also implied that five amino acid residues, including Cys, Pro, Met, Trp, and Phe, be related to the antioxidant activity of OM-GF17. Furthermore, OM-GF17 did not exhibit direct microbe-killing activity. This novel gene-encoded antioxidant peptide could help in the development of new antioxidant agents and increase our understanding of the biological functions of amphibian skin. [ABSTRACT FROM AUTHOR]

Insulinotropic peptide agents are regarded as potential candidates for anti-diabetic treatment. In the present study, a novel insulinotropic peptide, termed OA-A1, was purified from frog skin secretions of Odorrana andersonii. Mature OA-A1 was determined to be a 1965.049 Da peptide with an amino acid sequence of LVGKLLKGAVGDVCGLLPIC, in which an intramolecular disulfide bridge was formed by two cysteine residues. At the cellular level, OA-A1 exhibited potent proliferation promoting effects on mouse-derived pancreatic β-TC-6 cells and significantly stimulated insulin release in β-TC-6 cells at a minimum concentration of 1 nM. In the animal model, OA-A1 also showed a dose-dependent insulin-releasing role in mice. At concentrations ranging from 1 nmol/kg to 1 μmol/kg, OA-A1 had a significant acute hypoglycemic effect on streptozotocin (STZ)-induced diabetic mice. The pancreatic islet areas of diabetic mice increased dose-dependently after 21 days of OA-A1 treatment (1-100 nmol/kg) compared with those of the saline control group. Moreover, OA-A1 significantly improved the oral glucose tolerance of STZ-induced diabetic mice. Taken together, these results suggest that OA-A1 provides an excellent template for the development of novel anti-diabetic therapeutic agents. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Pain is a major symptom of many diseases and results in enormous pressures on human body or society. Currently, clinically used analgesic drugs, including opioids and nonsteroidal anti-inflammatory drugs, have adverse reactions, and thus, the development of new types of analgesic drug candidates is urgently needed. Animal venom peptides have proven to have potential as new types of analgesic medicine. In this research, we describe the isolation and characterization of an analgesic peptide from the crude venom of centipede, Scolopendra subspinipes mutilans. The amino acid sequence of this peptide was identical with SsmTX-I that was previously reported as a specific Kv2.1 ion channel blocker. Our results revealed that SsmTX-I was produced by posttranslational processing of a 73-residue prepropeptide. The intramolecular disulfide bridge motifs of SsmTX-I was Cys1-Cys3 and Cys2-Cys4. Functional assay revealed that SsmTX-I showed potential analgesic activities in formalin-induced paw licking, thermal pain, and acetic acid-induced abdominal writhing mice models. Our research provides the first report of cDNA sequences, disulfide motif, successful synthesis, and analgesic potential of SsmTX-I for the development of pain-killing drugs. It indicates that centipede peptide toxins could be a treasure trove for the search of novel analgesic drug candidates. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: The characterization of new natural antimicrobial peptides (AMPs) can help to solve the serious problem of bacterial resistance to currently used antibiotics. In the current study, we analyzed two families of AMPs from the Chinese torrent frog Amolops jingdongensis with a range of bioactivities. The first family of peptides, named jindongenin-1a, is 24 amino acids in length; a BLAST search of jindongenin-1a revealed no sequence similarity with other AMPs. The second family consists of two peptides containing 29 amino acid residues each. These peptides have high sequence similarity with the AMPs of palustrin-2 and are therefore designated palustrin-2AJ1 and palustrin-2AJ2. The cDNA sequences encoding these AMPs have been cloned and the deduced protein sequence of each AMP has been determined by protein sequencing. Sequence and structural analysis showed that each precursor is composed of a putative signal peptide, an N-terminal spacer, a processing site and a disulfide-bridged heptapeptide segment at the C-terminus. We synthesized jindongenin-1a and palustrin-AJ1 to test their antimicrobial, hemolytic, antioxidative and cytotoxic activities. These two peptides showed broad-spectrum antimicrobial activity to standard and clinically isolated strains of bacteria. In addition, they exhibited weak hemolytic activity to human and rabbit erythrocytes under our experimental conditions. Moreover, these peptides also displayed cytotoxic activity against the K562 and HT29 mammalian cell lines and low anti-oxidant activity. These findings provide helpful insight that will be useful in the design of anti-infective peptide agents. [Copyright &y& Elsevier]

At present, there are no satisfactory therapeutic drugs for the functional recovery of spinal cord injury (SCI). We previously identified a novel peptide (OM-LV20) that accelerated the regeneration of injured skin tissues of mice and exerts neuroprotective effects against cerebral ischemia/reperfusion injury in rats. Here, the intraperitoneal injection of OM-LV20 (1 μg/kg) markedly improved motor function recovery in the hind limbs of rats with traumatic SCI, and further enhanced spinal cord repair. Administration of OM-LV20 increased the number of surviving neuron bodies, as well as the expression levels of brain-derived neurotrophic factor (BDNF) and its receptor tyrosine receptor kinase B (TrkB). In the acute stage of SCI, OM-LV20 treatment also increased superoxide dismutase and glutathione content but decreased the levels of malonaldehyde and nitric oxide. Thus, OM-LV20 significantly promoted structural and functional recovery of SCI in adult rats by increasing neuronal survival and BDNF and TrkB expression, and thereby regulating the balance of oxidative stress. Based on our knowledge, this research is the first report on the effects of amphibian-derived peptide on the recovery of SCI and our results highlight the potential of peptide OM-LV20 administration in the acceleration of the recovery of SCI. • Active peptide OM-LV20 can promote the repair of spinal cord injury (SCI). • OM-LV20 can significantly improve the recovery of motor function of the hindlimb in rats with traumatic SCI. • Administration of OM-LV20 increased the number of surviving neuron bodies. • OM-LV20 might play a neuroprotective role by balancing the redox system in the body. [ABSTRACT FROM AUTHOR]

Ischemia/reperfusion (I/R) is a common injury leading to ischemic stroke. At present, I/R treatment remains limited, highlighting the urgent need for the discovery and development of new protective drugs for brain injury. Here, we investigated the neuroprotective effects of short peptide OM-LV20 previously identified from amphibian against I/R rats. Results showed that intraperitoneal administration of OM-LV20 (20 ng/kg) significantly reduced infarct area formation, improved behavioral abnormalities, and protected cortical and hippocampal neurons against death caused by I/R. Moreover, the underlying molecular mechanism was involved with the regulation of the MAPK and BDNF/AKT signaling pathways, as well as the levels of cyclic adenosine monophosphate, pituitary adenylate cyclase-activating polypeptide receptor, and tryptophan hydroxylase 1. To the best of our knowledge, this research was the first report to describe the neuroprotective effects of an amphibian skin secretion-derived peptide in I/R rats and highlighted OM-LV20 as a promising drug candidate for the development of novel anti-stroke therapies. Image 1 • A short active peptide OM-LV20 was reported to have anti-stroke effects in I/R rats. • It was the first time to show that amphibian-skin-secretion-derived peptide had neuroprotective effects in I/R rats. • The underlying molecular mechanism was involved activate the MAPK and BDNF/Akt pathway to protect neurons against death. [ABSTRACT FROM AUTHOR]

Ischemic stroke is a severe threat to human health due to its high recurrence, mortality, and disability rates. As such, how to prevent and treat ischemic stroke effectively has become a research hotspot in recent years. Here, we identified a novel peptide, named HsTx2 (AGKKERAGSRRTKIVMLKCIREHGH, 2 861.855 Da), derived from the scorpion Heterometrus spinifer , which showed obvious anti-apoplectic effects in rats with ischemic stroke. Results further demonstrated that HsTx2 significantly reduced formation of infarct area and improved behavioral abnormalities in ischemic stroke rats. These protective effects were likely exerted via activation of the mitogen-activated protein kinase (MAPK) signaling pathway, i.e., up-regulation of phosphorylated ERK1/2 in both rat cerebral cortex and activated microglia (AM); up-regulation of phosphorylated p38 (p-p38) in the cerebral cortex; and inhibition of phosphorylated JNK and p-p38 levels in the AM. In conclusion, this study highlights HsTx2 as a potential neuroprotective agent for stroke. • A novel peptide HsTx2 showed obvious anti-apoplectic effects in rats with ischemic stroke. • HsTx2 significantly reduced formation of infarct area and improved behavioral abnormalities in ischemic stroke rats. • The protective effects of HsTx2 were likely exerted via activation of the MAPK signaling pathway. [ABSTRACT FROM AUTHOR]

Cerebral ischemia-reperfusion (I/R) is the main cause of neurological injury after stroke. However, existing treatments for I/R injury are relatively poor, and relevant drugs need to be further explored. Amphibians have received increasing attention as a resource bank of bioactive peptides. However, reports on neuroprotective peptides from amphibians remain extremely rare. Here, we identified a new neuroprotective peptide (OL-FS13, amino acid sequence: FSLLLTWWRRRVC) from the odorous frog species Odorrana livida using a constructed cDNA library. OL-FS13 significantly improving infarct volume, behavioral and histological abnormalities in rats, and also showed neuroprotective activities in PC12 cell (by oxygen glucose deprivation/reoxygenation, OGD/R). Mechanistically, OL-FS13 increased the level of antioxidative enzymes to resist oxidative stress and alleviated endoplasmic reticulum (ER) stress induced by I/R and OGD/R. The use of ML385 (Nrf2 inhibitor) indicated that OL-FS13 relieved nerve damage caused by oxidative and ER stress by increasing the nuclear displacement of Nrf2. Collectively, this research provides a novel drug candidate for the clinical cerebral I/R curation. [Display omitted] • This research provides a potential drug candidate (OL-FS13) for the clinical treatment of cerebral ischemia reperfusion. • OL-FS13 exerted significant anti-stroke activities by alleviating oxidative and endoplasmic reticulum stress via activation of Nrf2 signaling and suppression of the IRE1α/TRAF2/JNK pathway. • OL-FS13 can be administered after cerebral ischemia reperfusion instead of prophylactic administration, which improves its clinical application value. [ABSTRACT FROM AUTHOR]

Lipopolysaccharide (LPS) is a major pathogen-associated pattern molecule that can initiate lethal sepsis. Bioactive peptides in amphibian skin secretions, especially antimicrobial peptides, are essential components of the host immune system and help fight the microbial invasion. In this study, two peptides: peptide 1 (KINRKGPRPPG) and peptide 2 (INRKGPRPPG) were isolated, from skin secretions of the Chinese red belly frog (Bombina maxima). After stimulation with LPS, peptide 1 showed direct LPS-binding activity, low cytotoxicity, immunoregulatory functions in vitro , and neutralizing LPS effects in animal models. Thus, natural peptide 1 exhibits potential as an ideal candidate against LPS. • The peptide 1 (KINRKGPRPPG) and peptide 2 (INRKGPRPPG) were isolated from skin secretions of Bombina maxima. • The peptide 1 showed direct lipopolysaccharide-binding activity, low cytotoxity, immunoregulatory functions in vitro. • The peptide 1 could neutralize lipopolysaccharide effects in animal models. • The peptide 1 exhibits an ideal candidate against lipopolysaccharide. [ABSTRACT FROM AUTHOR]

Borosilicate glass–ceramics precursors with varying compositional ratios in the CaO–SiO 2 –B 2 O 3 (CBS) system were synthesized by sol–gel method. The precursors were calcined at 1200 °C for 2 h to form glass powders. The glass–ceramics were prepared by overlaying glass slurries on the substrates before sintering at different temperatures. The as-prepared glasses and glass–ceramics were characterized by differential scanning calorimetry and X-ray diffraction. The crystallization activation energies ( E c ) were calculated using the Kissinger method from DSC results. The morphology and crystallization behavior of the glass–ceramics were monitored by scanning electron microscopy. Both glass transition and crystallization temperatures decreased, however, the metastable zone increased. The E c values of CBS glasses and glass–ceramics were 254.1, 173.2 and 164.4 kJ/mol with increasing B 2 O 3 content, whereas that of the calcined G3 glass was 104.9 kJ/mol. Finally, the coatings were prepared at a low temperature (700 °C). The crystals that grew on the surface of multilayer coatings demonstrated heterogeneous surface nucleation and crystallization after heat-treatment from 700 °C to 850 °C for 4 h. [ABSTRACT FROM AUTHOR]