title: Antioxidant peptidomics reveals novel skin antioxidant system.
abstract: It is generally agreed that reactive oxygen species (ROS) contribute to skin aging, skin disorders, and skin diseases. Skin possesses an extremely efficient antioxidant system. This antioxidant activity is conferred by two systems: antioxidant enzymes and small molecules that can scavenge ROS by donating electrons. No gene-encoded secreted ROS scavengers have been reported. Amphibian skin is a multifunctional organ acting in defense, respiration, and water regulation, although it seems susceptible. Amphibian skins are easily harmed by biological or non-biological attacks such as microorganism infection or radiation injury. Among vertebrates, skins of amphibian are exposed to more dangers of radiation injury than others. Radiation toxicity occurs by directly attacking the genetic material and/or by generating ROS. In addition, amphibian skin respiration and inflammatory response also induce ROS generation. It is rational to hypothesize that amphibian skins should have potent free radical scavenging and radioprotective ability for their survival. Rana pleuraden is distributed in Southwest of China; it lives in the subtropical plateau (altitude around 2300 m) where there is strong ultraviolet radiation and long duration of sunshine. By peptidomics and genomics approaches, a large amount of antioxidant peptides belonging to 11 different groups with variable structures were isolated from the skin secretions of R. pleuraden. Their free radical scavenging and anti-inflammatory abilities were studied. All of these peptide share highly homologous preproregions, although mature antioxidant peptides have very divergent primary structures, suggesting the possibility of a common ancestor. Some peptides were also found to have multifunctional properties, such as combined antioxidant, anti-inflammatory, and antimicrobial activities. According to our knowledge, no gene-encoded specific antioxidant peptides have been reported except metallothionein. Our work possibly reveals a new skin antioxidant system. The current work also provides a large amount of peptide candidates with medical-pharmaceutical significance.
authors.affiliation: Biotoxin Units of Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China.
authors.forename: Hailong
authors.initials: H
authors.lastname: Yang
authors.forename: Xu
authors.initials: X
authors.lastname: Wang
authors.forename: Xiuhong
authors.initials: X
authors.lastname: Liu
authors.forename: Jing
authors.initials: J
authors.lastname: Wu
authors.forename: Cunbao
authors.initials: C
authors.lastname: Liu
authors.forename: Weiming
authors.initials: W
authors.lastname: Gong
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Zhao
authors.forename: Jing
authors.initials: J
authors.lastname: Hong
authors.forename: Donghai
authors.initials: D
authors.lastname: Lin
authors.forename: Yizheng
authors.initials: Y
authors.lastname: Wang
authors.forename: Ren
authors.initials: R
authors.lastname: Lai
mesh_terms: D000478:Alkylation / Q000187:drug effects; D000595:Amino Acid Sequence; D000818:Animals; D000890:Anti-Infective Agents / Q000737:chemistry / Q000494:pharmacology; D000893:Anti-Inflammatory Agents / Q000737:chemistry / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000494:pharmacology; D000975:Antioxidants / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects; D001713:Biphenyl Compounds / Q000494:pharmacology; D016166:Free Radical Scavengers / Q000737:chemistry / Q000494:pharmacology; D005658:Fungi / Q000187:drug effects; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction / Q000187:drug effects; D010455:Peptides / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D010851:Picrates / Q000494:pharmacology; D021382:Protein Sorting Signals; D040901:Proteomics; D011898:Ranidae; D012867:Skin / Q000378:metabolism*
chemical_list: D000890:Anti-Infective Agents; D000893:Anti-Inflammatory Agents; D023181:Antimicrobial Cationic Peptides; D000975:Antioxidants; D001713:Biphenyl Compounds; D016166:Free Radical Scavengers; D010455:Peptides; D010851:Picrates; D021382:Protein Sorting Signals; C004931:1,1-diphenyl-2-picrylhydrazyl