The emergence of carbapenem-resistantAcinetobacter baumanniiandPseudomonas aeruginosaraises fears of untreatable infections and poses the greatest health threats. Antimicrobial peptides (AMPs) are regarded as the most ideal solution to this menace. In this study, a set of peptides was designed based on our previously reported peptide cathelicidin-BF-15, and the lead peptide ZY4, a cyclic peptide stabilized by a disulfide bridge with high stability in vivo (the half-life is 1.8 h), showed excellent activity againstP. aeruginosaandA. baumannii, including standard and clinical multidrug-resistant (MDR) strains. ZY4 killed bacteria by permeabilizing the bacterial membrane and showed low propensity to induce resistance, exhibited biofilm inhibition and eradication activities, and also killed persister cells. Notably, administration of ZY4 decreased susceptibility to lung infection byP. aeruginosaand suppressed dissemination ofP. aeruginosaandA. baumanniito target organs in a mouse septicemia infection model. These findings identify ZY4 as an ideal candidate against MDR bacterial infections.

No abstract

Centipedes are excellent predatory arthropods that inject venom to kill or immobilize their prey. Although centipedes have long been known to be venomous, their venoms remain largely unexplored. The chemical components responsible for centipede predation and the functional mechanisms are unknown. Twenty-six neurotoxin-like peptides belonging to ten groups were identified from the centipede venoms, Scolopendra subspinipes mutilans L. Koch by peptidomics combined with transcriptome analysis, revealing the diversity of neurotoxins. These neurotoxins each contain two to four intramolecular disulfide bridges, and in most cases the disulfide framework is different from that found in neurotoxins from the venoms of spiders, scorpions, marine cone snails, sea anemones, and snakes (5S animals). Several neurotoxins contain potential insecticidal abilities, and they are found to act on voltage-gated sodium, potassium, and calcium channels, respectively. Although these neurotoxins are functionally similar to the disulfiderich neurotoxins found in the venoms of 5S animals in that they modulate the activity of voltage-gated ion channels, in almost all cases the primary structures of the centipede venom peptides are unique. This represents an interesting case of convergent evolution in which different venomous animals have evolved different molecular strategies for targeting the same ion channels in prey and predators. Moreover, the high level of biochemical diversity revealed in this study suggests that centipede venoms might be attractive subjects for prospecting and screening for peptide candidates with potential pharmaceutical or agrochemical applications. Molecular & Cellular

New therapeutic agents for Candida albicans vaginitis are urgently awaiting to be developed because of the increasing antibiotic resistance of C. albicans. Antimicrobial peptides (AMPs) are one of the most promising choices for next-generation antibiotics. In this study, novel peptides were designed based on snake venom antimicrobial peptide cathelicidin-BF to promote anti-C. albicans activity and decrease side-effects. The designing strategies include substitutions of charged or hydrophobic amino acid residues for noncharged polar residues to promote antimicrobial activity and insertion of a hydrophobic residue in the hydrophilic side of the helix structure to reduce hemolysis. A designed tryptophan and lysine/arginine-rich cationic peptide 4 (ZY13) (VKRWKKWRWKWKKWV-NH2) exhibited excellent antimicrobial activity against either common strain or clinical isolates of antibiotic-resistant C. albicans with little hemolysis. Peptide 4 showed significant therapeutic effects on vaginitis in mice induced by the infection of clinical antibiotic-resistant C. albicans. The approaches herein might be useful for designing of AMPs.

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 μg/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 β1 (TGF-β1) 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.

Rationale: Epidemiologic studies have identified an associate between iron deficiency (ID) and the use of oral contraceptives (CC) and ischemic stroke (IS). To date, however, the underlying mechanism remains poorly understood. Both ID and CC have been demonstrated to up-regulate the level and iron-binding ability of transferrin, with our recent study showing that this up-regulation can induce hypercoagulability by potentiating FXIIa/thrombin and blocking antithrombin-coagulation proteases interactions. Objective: To investigate whether transferrin mediates IS associated with ID or CC and the underlying mechanisms. Methods and Results: Transferrin levels were assayed in the plasma of IS patients with a history of iron-deficiency anemia (IDA), IDA patients, venous thromboembolism patients using CC, and ID mice, and in the cerebrospinal fluid of some IS patients. Effects of ID and estrogen administration on transferrin expression and coagulability and the underlying mechanisms were studied in vivo and in vitro. High levels of transferrin and transferrin-thrombin/FXIIa complexes were found in patients and ID mice. Both ID and estrogen up-regulated transferrin through hypoxia and estrogen response elements located in the transferrin gene enhancer and promoter regions, respectively. In addition, ID, administration of exogenous transferrin or estrogen, and transferrin overexpression promoted platelet-based thrombin generation and hypercoagulability, and thus aggravated IS. In contrast, anti-transferrin antibodies, transferrin knockdown, and peptide inhibitors of transferrin-thrombin/FXIIa interaction exerted anti-IS effects in vivo. Conclusions: Our findings revealed that certain factors (i.e., ID and CC) up-regulating transferrin are risk factors of thromboembolic diseases decipher a previously unrecognized mechanistic association among ID, CC and IS and provide a novel strategy for the development of anti-IS medicine by interfering with transferrin-thrombin/FXIIa interactions.

Coagulation balance is maintained through fine-tuned interactions among clotting factors, whose physiological concentrations vary substantially. In particular, the concentrations of coagulation proteases (pM to nM) are much lower than their natural inactivator antithrombin (AT,~3 μM), suggesting the existence of other coordinators. In the current study, we found that transferrin (normal plasma concentration~40 μM) interacts with fibrinogen, thrombin, factor XIIa (FXIIa), and AT with different affinity to maintain coagulation balance. Normally, transferrin is sequestered by binding with fibrinogen (normal plasma concentration~10 μM) at a molar ratio of 4:1. In atherosclerosis, abnormally up-regulated transferrin interacts with and potentiates thrombin/FXIIa and blocks AT's inactivation effect on coagulation proteases by binding to AT, thus inducing hypercoagulability. In the mouse model, transferrin overexpression aggravated atherosclerosis, whereas transferrin inhibition via shRNA knockdown or treatment with antitransferrin antibody or designed peptides interfering with transferrin-thrombin/FXIIa interactions alleviated atherosclerosis. Collectively, these findings identify that transferrin is an important clotting regulator and an adjuster in the maintenance of coagulation balance and modifies the coagulation cascade.

Non-small cell lung cancer (NSCLC) is a common type of lung cancer, characterized by a poor prognosis. In the last several years, more and more studies have demonstrated the significant roles played by circular RNAs (circRNAs) in different human tumors progression including NSCLC. The present study was to explore the mechanism of hsa_circ_101237 in regulating non-small cell lung cancer (NSCLC). Totally 303 NSCLC cases were enrolled. A549 and H1299 cells were transfected. Cells viability, migration and invasion were determined by CCK-8 assay and transwell experiment, respectively. Luciferase reporter gene assay and RNA immunoprecipitation (RIP) assay were performed. hsa_circ_101237, miR-490-3p and MAPK1 expression in tissues/cells were detected by qRT-PCR. The study found an elevation in the expression of Hsa_circRNA_101237 in both NSCLC tissues and cell line. High Hsa_circRNA_101237 expression predicted poor survival in NSCLC. Meanwhile, we found that hsa_ circRNA_101237 expression sponged miR-490-3p to enhance MAPK1 expression, thus significantly promoting NSCLC cell lines proliferation, migration, and invasion. MAPK1 restoration prevented NSCLC cells proliferation, migration, and invasion to be repressed due to hsa_circRNA_101237 knockdown. To sum up, as revealed by the study, hsa_circRNA_101237 promoted the expression of MAPK1 via miRNA-490-3p sponge, thus affecting the NSCLC as an important onco-circRNA. Lung cancer, characterized by a poor prognosis but a high morbidity, is a common malignant tumor, non-small cell lung cancer (NSCLC) are identified as the most common type of lung cancer (occupying about 85%) 1. As is well known, smoking is the main cause of NSCLC 2. As NSCLC does not show obvious clinical symptoms and the screening programs are not effective, most patients with NSCLC, once they are diagnosed, are at advanced stages with a poor prognosis 3. More and more clinical studies found that metastasis greatly hinders the treatment of NSCLC cancer; therefore, in-depth understanding the metastasis mechanisms is beneficial for effectively treating NSCLC. Circular RNAs (circRNAs) are a kind of non-coding RNAs with endogenous and conserve, forming a covalently closed continuous loop via back-splice without 3ʹ-end or 5ʹ-end 4. Due to the feature, circRNAs exhibit a lot of properties, and many properties were found not long ago. circRNAs have a special closed loop structure, making them able to resist the degradation medicated by exonuclease. On that account, they are more stable compared with most other linear RNAs, thus they can be used as a biomarker to effectively diagnose and treat cancers 5. circRNAs can interact with RNA-binding proteins, so as to regulate target gene expression 6. Besides, it has been indicated that circRNAs can be sinks for miRNAs, to control the function processed by miRNAs 7. Many human cancers see altered circRNA expression, and many researches have revealed the key role played by circR-NAs in the tumorigenesis. circRNA_101237, a new circRNA identified recently, whose encoding ge...