The Mechanism Of Worenine Suppresses Solar Ultraviolet-Induced Skin Inflammation By Targeting C-Jun N-Terminal Kinases

Background:Solar ultraviolet always results in skin inflammation even the skin cancer.The traditional ultraviolet protection compounds are limited because of it’s side effect.So it’s necessary to develop a ultraviolet protection compounds which has less side effect.Recently,natural molecules have became a hot spot of this area because of its anti-inflammation and antioxidant effect to provide multiaspect and long-term protection to skin.Coptis is a traditional Chinese medicine which can suppress inflammation.As the effective constituent of coptis,the mechanism of worenine in skin inflammation is still unknown to us.Objective:To explore the mechanism of a natural molecule worenine on ultraviolet-induced inflammation precaution.Methods:(1)Computer screening and protein kinase assay are used to find the target of worenine.(2)Microscale thermophoresis(MST)were performed to verify the interaction between worenine and JNK2 and compute the dissociation constant K_D.(3)In vitro kinase assay were performed to explore the impact that worenine has on JNK2 activity.(4)The impact of worenine of different concentrations on cell viability was observed through MTT assay.(5)Ultraviolet-induced inflammation model of cells was established.Before exposure to ultraviolet,cells were pretreated by worenine with different concentrations or different timings.The levels of p-JNK2,p-p38 and p-ATF2 were detected by Western Blot and the production of inflammation factor IL-6 was detected by ELISA.(6)The nude skins of mouse were pretreated with unguent mixed with worenine before exposing to ultraviolet.H&E staining of skin tissues showed the pathological changes of ultraviolet-induced skin inflammation.p-JNK2,p-p38 and inflammation factor IL-6levels in skin tissues were detected by Western Blot and ELISA.Results:(1)Worenine could bind with JNK2 and suppress the activity of JNK2 in dose-dependent manner,and the dissociation constant is 116.41μM.(2)Pretreatment with worenine could decrease the phosphorylation of JNK2,p38 and ATF2 in ultraviolet-induced cells.Meanwhile,worenine could also suppress the inflammation factor IL-6 production which induced by ultraviolet.(3)In mouse model,thickening of epidermis and infiltration of inflammation cells which were induce by ultraviolet could be alleviated by worenine.The increasing of levels of p-JNK2,p-p38 and IL-6 were also blocked by worenine.Conclusions:(1)Worenine could suppress the activity of JNK2 by directly binding with JNK2.(2)Worenine could suppress JNK2 and alleviate UV induced inflammation.(3)Worenine is potential to be developed as a drug that can prevent and cure ultraviolet-induced skin inflammation.