Proteomic analysis of the skin of Chinese giant salamander (Andrias davidianus)
Graphical abstract
Introduction
The Chinese giant salamander (Andrias davidianus), belonging to order Caudata, family Cryptobranchidae, is the largest extant amphibian species. It occurs mostly in southwestern and eastern China and is classified as a class II protected species in China [1] and as one of the top 10 “focal species” by the Evolutionarily Distinct and Globally Endangered (EDGE) project in 2008 (http://www.edgeofexistence.org/). It is renowned as a living fossil, since it has been in existence for more than 350 million years [2], [3]. The evolution history of this species likely involves adaptations [4], [5], and its ancestral organisms may have represented transition steps from aquatic to terrestrial life, so this species has an important value in scientific research of skin system.
The skin of Chinese giant salamander is dark brown, black or greenish in color and irregularly blotched. It is also rough, wrinkled and porous which facilitates respiration through the skin as this large amphibian lacks gills. The skin is a multi functional organ acting in defense and cutaneous respiration [6], and is covered in mucus which protects their bodies from abrasions and parasites. When irritated or grasped, giant salamanders produce a milky, sticky secretion with heavy and astringency smell owing to its developed mucous gland. The main ingredients of skin mucus are sticky glycoproteins and fiber materials. Generally, the mucous secretions have antibacterial, antioxidation, antitumor, fatigue-resistant, and strengthened immunity [7], [8], [9]. Like other amphibians, this salamander has smooth skin that lacks scales, and the molting is the normal metabolism of the skin. Molting is a process of constant renewal of the outer layer of epidermis (stratum corneum) in amphibians, which provides a barrier against injury, pathogens and evaporative water loss [10]. In the private sector, the powder of giant salamander molting mixed with tung oil was utilized to treat burns [11]. In view of these characteristics, the research on Chinese giant salamander skin has important scientific significance. Therefore, it is of great interest to elucidate the proteome of its skin, mucus and molting. On the other hand, there is an urgent need to understand the defense reaction of Chinese giant salamander skin, due to the fact that a dramatic decline in the population has resulted from emerging infectious diseases [12], [13].
Despite the high public profile of Chinese giant salamander and their unique life-history characteristics, this species remains poorly characterized at the molecular level. Fortunately, proteomics can provide a global and comprehensive approach to the identification and description of biochemical processes at the protein level. Although several proteomic studies have focused on functional proteome of the human and mouse skin [14], [15], [16] and on the skin secretome of the frog [17], [18], the comprehensive proteomic profiling of Chinese giant salamander skin, is still unknown. This present study attempts to employ large-scale proteomic analysis to establish the functional proteome in the skin, mucus and molting of Chinese giant salamander. We identified 249 proteins in the skin, 155 proteins in the mucus, and 97 proteins in the molting using two-dimensional gel electrophoresis (2DE) coupled with mass spectrometry (MS). Gene Ontology (GO) analysis showed that these proteins participated in various physiological activities, including extracellular matrix organization, defense, immune response, wound healing, respiration, etc. This study provides some interesting new insights in the proteomes of the skin, mucus and molting of Chinese giant salamander, and may also provide a basis for characterizing and comparing the skin proteomes from other amphibian species.
Section snippets
Animals
Three or four year old male healthy Chinese giant salamanders with body length of 60–100 cm and weight of about 3 kg, were obtained from a giant salamander breeding base in Wen Quan Zhen, Kaixian Country, Chongqing Municipality, China. The molting was obtained from the breeding pool of Chinese giant salamanders. The mucus was secreted by the dorsal skin of Chinese giant salamanders under the scraping stimulation with a triangle, and was collected in a sterile tube. Subsequently, they were
Histology of the Chinese giant salamander skin
Chinese giant salamanders (Fig. 1A and B) were obtained from a giant salamander breeding base, and Chinese giant salamander with the secreted mucus was shown in Fig. 1B. Moreover, the histological appearance of the skin tissue in transverse section was shown in Fig. 1C. The organizational structure of the skin is composed of three basic layers: the epidermal layer, the dermal layer, and the subcutaneous layer. The epidermal layer is made up of 2–5 layers of skin cells and the outer-most layer
Discussion
The Chinese giant salamander (A. davidianus), renowned as a living fossil, is the largest extant tailed amphibian species in the world [2], [3]. The number of Chinese giant salamander is in global decline, with extinction threats coming from various sources, not only from environmental disruption, predation and pollution, but also from fungal and viral pathogens [12], [13]. Understanding the susceptibility of giant salamander to these pathogens is a major challenge. Giant salamander skin
Transparency document
Acknowledgments
This work was supported by grants from the National Basic Research 973 Pre-research Program of China (No. 2012CB722304), the Major Scientific and Technological Projects of Henan (111100910600), and the Foundation and Advanced Technology Research Program of Henan (No. 132300413208, No. 132300410134 and No. 142300413212).
References (56)
- et al.
Ultrastructural morphogenesis of an amphibian iridovirus isolated from Chinese giant salamander (Andrias davidianus)
J Comp Pathol
(2014) - et al.
Antioxidant peptidomics reveals novel skin antioxidant system
Mol Cell Proteomics
(2009) - et al.
First report of a ranavirus associated with morbidity and mortality in farmed Chinese giant salamanders (Andrias davidianus)
J Comp Pathol
(2011) - et al.
Proteomic anatomy of human skin
J Proteomics
(2013) - et al.
Proteomics of skin proteins in psoriasis: discovery and verification in a mouse model to confirmation in humans
Mol Cell Proteomics
(2015) - et al.
Identification and characterization of new protein chemoattractants in the frog skin secretome
Mol Cell Proteomics
(2006) - et al.
Differential proteome analysis of the cell differentiation regulated by BCC, CRH, CXCR4, GnRH, GPCR, IL1 signaling pathways in Chinese fire-bellied newt limb regeneration
Differentiation
(2014) - et al.
Identification and characterization of antimicrobial peptides from skin of Amolops ricketti (Anura: Ranidae)
Peptides
(2012) - et al.
Molecular cloning and characterization of antimicrobial peptides from skin of the broad-folded frog, Hylarana latouchii
Biochimie
(2012) - et al.
Anti-infection peptidomics of amphibian skin
Mol Cell Proteomics
(2007)
Peptidomic analysis of skin secretions demonstrates that the allopatric populations of Xenopus muelleri (Pipidae) are not conspecific
Peptides
Minor cartilage collagens type IX and XI are expressed during embryonic stem cell-derived in vitro chondrogenesis
Ann Anat
A novel and highly conserved collagen (pro(alpha)1(XXVII)) with a unique expression pattern and unusual molecular characteristics establishes a new clade within the vertebrate fibrillar collagen family
J Biol Chem
The role of amphibian antimicrobial peptides in protection of amphibians from pathogens linked to global amphibian declines
Biochim Biophys Acta
Identification of multiple peptides with antioxidant and antimicrobial activities from skin and its secretions of Hylarana taipehensis, Amolops lifanensis, and Amolops granulosus
Biochimie
Development of antimicrobial peptide defenses of southern leopard frogs, Rana sphenocephala, against the pathogenic chytrid fungus, Batrachochytrium dendrobatidis
Dev Comp Immunol
Thymus cDNA library survey uncovers novel features of immune molecules in Chinese giant salamander Andrias davidianus
Dev Comp Immunol
Extensive diversification of MHC in Chinese giant salamanders Andrias davidianus (Anda-MHC) reveals novel splice variants
Dev Comp Immunol
Brief report. The karyotype of the caudate amphibian Andrias davidianus
Hereditas
Earliest known crown-group salamanders
Nature
Late Jurassic salamanders from northern China
Nature
Biomechanics and hydrodynamics of prey capture in the Chinese giant salamander reveal a high-performance jaw-powered suction feeding mechanism
J R Soc Interface
Characterization and bioactivity of antimicrobial peptides from the skin secretions of the Andrias davidianus
Chin J Biochem Pharmacol
Major biological activities of the skin secretion of the Chinese giant salamander, Andrias davidianus
Z Naturforsch C
Skin secretion and shedding is a good source for non-destructive genetic sampling in the Chinese giant salamander (Andrias davidianus)
Z Naturforsch C
Ontogenetic comparison of the molting frequency in Rhinella marina (Anura: Bufonidae)
Iheringia Ser Zool
The anti-inflammatory and analgesic action of the skin powder of Andrias davidianus
Henan Tradit Chin Med
Iridovirus infection in Chinese giant salamanders, China, 2010
Emerg Infect Dis
Cited by (38)
A hydrogel derived from skin secretion of Andrias davidianus to facilitate bone regeneration
2024, Composites Part B: EngineeringTranscriptomic analysis of Andrias davidianus meat and experimental validation for exploring its bioactive components as functional foods
2024, Food Science and Human WellnessRecent advances in biomimetic hemostatic materials
2023, Materials Today BioUnderwater instant adhesion mechanism of self-assembled amphiphilic hemostatic granular hydrogel from Andrias davidianus skin secretion
2022, iScienceCitation Excerpt :The major components found in ADS were proteins (accounting for ∼90 wt %), polysaccharides (∼6 wt %)and fatty acids (∼4 wt %). There are ∼150 proteins and 17 amino acids found in the secretion according to the proteomic analysis results (Data S1) (Geng et al., 2015). Because of the limited amount of catechol or other reactive groups such as thiols found in ADS and the total dissolution of ADS hydrogel in hexafluoroisopropanol (HFIP), the catechol chemistry or covalent bonding (disulfide) mechanism could be excluded.
Stem from nature: Bioinspired adhesive formulations for wound healing
2022, Journal of Controlled Release