Peptides for Skin Protection and Healing in Amphibians

Abstract

Amphibian skin is not to be considered a mere tegument; it has a multitude of functions related to respiration, osmoregulation, and thermoregulation, thus allowing the individuals to survive and thrive in the terrestrial environment. Moreover, amphibian skin secretions are enriched with several peptides, which defend the skin from environmental and pathogenic insults and exert many other biological effects. In this work, the beneficial effects of amphibian skin peptides are reviewed, in particular their role in speeding up wound healing and in protection from oxidative stress and UV irradiation. A better understanding of why some species seem to resist several environmental insults can help to limit the ongoing amphibian decline through the development of appropriate strategies, particularly against pathologies such as viral and fungal infections.

Metabolites from Microbes Isolated from the Skin of the Panamanian Rocket Frog Colostethus panamansis (Anura: Dendrobatidae)

“…Tryptophan derivatives such as 1 and 2, are well known for exhibiting antioxidant and immunomodulatory properties [ 55 , 56 ]. In terms of immunoregulatory properties, these skin-associated bacterial metabolites may influence the response from the host’s immune system to help fight off infection [ 57 ].…”

The Antioxidant Peptide Salamandrin-I: First Bioactive Peptide Identified from Skin Secretion of Salamandra Genus (Salamandra salamandra)

“…Amphibians are widely distributed across numerous habitats worldwide. Most amphibians produce secretions that are released onto their skin when myocytes surrounding the granular glands contract in response to stimuli promoted by the sympathetic nervous system [1]. Amphibian secretions have been used for centuries as ethno-pharmaceutical drugs in Asia and in the Americas for the treatment of several diseases, such as hemorrhages, allergies, inflammations and infections, and more recently have been considered as a prolific source of potential drug leads [2,3].…”

Novel Ocellatin Peptides Mitigate LPS-induced ROS Formation and NF-kB Activation in Microglia and Hippocampal Neurons

“…9A). After 30 minutes of incubation with Ocellatin-K1 (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16), no significant morphological changes in the cells were found at the concentrations tested (250, 500 and 1000 µg/mL; Fig. 9B-F, respectively).…”

“…Oxidative stress is a cellular or physiological condition with a high concentration of ROS that causes molecular damage to cellular structures 11 . Although cells contain a number of antioxidant defenses for minimizing ROS fluctuations, situations where ROS generation often exceed the antioxidant capacity of cells are correlated with the onset and progression of many diseases through mutations of DNA, protein oxidation, and lipid peroxidation with consequent functional alterations and loss of vital functions in several tissues or organs 12,13 . In this context, considering that the neuroanatomic region of the brain is highly vulnerable to oxidative stress, molecules such as amphibian antioxidant peptides, which rapidly exert their biological functions by eliminating free radicals within several seconds may serve as promising neuroprotective agents.…”

“…Ocellatin-K1(1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16) and Ocellatin-K1(1-21) protect hippocampal neurons from oxidative stress induced by LPS-treated-microglial conditioned media. Representative confocal images and quantification of ROS production in hippocampal neurons incubated with conditioned medium from microglia subjected to LPS-induced and 100 μM Ocellatin-K1(1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16) or Ocellatin-K1(1-21). Images show neurons expressing mVenus (green) and the Hyper Red ROS biosensor (red).…”