UV Radiation‐induced Peptides in Frog Skin Confer Protection Against Cutaneous Photodamage Through Suppressing MAPK Signaling

Overexposure to ultraviolet light (UV) has become a major dermatological problem since the intensity of ultraviolet radiation is increasing. As an adaption to outside environments, amphibians gained an excellent peptide‐based defense system in their naked skin from secular evolution. Here, we first determined the adaptation and resistance of the dark‐spotted frogs (Pelophylax nigromaculatus) to constant ultraviolet B (UVB) exposure. Subsequently, peptidomics of frog skin identified a series of novel peptides in response to UVB. These UV‐induced frog skin peptides (UIFSPs) conferred significant protection against UVB‐induced death and senescence in skin cells. Moreover, the protective effects of UIFSPs were boosted by coupling with the transcription trans‐activating (TAT) protein transduction domain. In vivo, TAT‐conjugated UIFSPs mitigated skin photodamage and accelerated wound healing. Transcriptomic profiling revealed that multiple pathways were modulated by TAT‐conjugated UIFSPs, including small GTPase/Ras signaling and MAPK signaling. Importantly, pharmacological activation of MAPK kinases counteracted UIFSP‐induced decrease in cell death after UVB exposure. Taken together, our findings provide evidence for the potential preventive and therapeutic significance of UIFSPs in UV‐induced skin damage by antagonizing MAPK signaling pathways. In addition, these results suggest a practicable alternative in which potential therapeutic agents can be mined from organisms with a fascinating ability to adapt.