Deletion Of P38γ Attenuates Ethanol Consumption-and Acetaminophen-induced Liver Injury In Mice Through Promoting Dlg1

Objective: Acetaminophen（APAP）is one of the main causes of drug-induced acute liver injury.Ethanol（Et OH）can aggravate APAP induced liver injury.The problem of liver injury induced by Et OH and APAP has become increasingly prominent,but the mechanism of liver injury induced by Et OH and APAP is still unclear.P38γ is a stress activated serine / threonine kinase,which can sense a variety of cardiac pathology and is closely related to the production of reactive oxygen species.It is composed of four subtypes: α、β、γ and δ。 Biochemical evidence suggests that individual subtypes have specific roles and are classified as stress activated kinases.Among the four subtypes,p38γis involved in the inflammatory response of different diseases.Bárbara et al.confirmed that liver metabolism can be re regulated by regulating neutrophil infiltration,p38γ is very important to regulate the cell cycle and affect the occurrence of liver tumors.Xu et al.Found that Et OH can activate Erb-B2 receptor tyrosine kinase 2（erb B2）/p38γsignaling pathway.In short,p38γ is highly likely to play an important role in lipid accumulation and oxidative stress in Et OH and APAP induced liver injury.In this study,we investigated the effects of p38γ on Et OH and APAP induced liver injury and the effects of Et OH and APAP induced genes related to lipid metabolism and oxidative stress levels in AML-12 cells.In addition,we also studied the specific regulation mechanism of p38γin Et OH and APAP induced liver injury.Methods: ALD C57BL/6 J mice model was induced by giving liquid diet containing 5%Et OH（v/v）for 10 days,followed by gavage of Et OH（25%（v/v）,6 g/kg）once or injecting APAP（200 mg/kg,ip）,or combined the both treatments.After the successful construction of the model,the specific localization and expression of p38γ in mouse liver can be detected.On the other hand,r AAV9-Sh RNA-p38γ adeno-associated virus was injected into C57BL/6J mice through caudal vein to construct p38γ silencing mouse model.After the successful construction of the model,mouse primary hepatocytes were obtained by in situ perfusion technology,and detect the expression levels of genes related to lipid metabolism（Fasn,Acox1,SREBP-1 and PPAR-α）by Western blotting and RT-q PCR.In vitro,mouse hepatocytes（AML-12 cells）were induced by Et OH and APAP,and then p38γ overexpression plasmid and p38γ-si RNA were transfected into the cells respectively.After the cell model was successfully constructed,the expression level of genes related to lipid metabolism（Fasn,Acox1,SREBP-1 and PPAR-α）was detected by Western blotting and RT-q PCR.Finally,the specific regulatory mechanism of p38γ on Et OH and APAP induced liver injury in mice was observed.Results: In this study,the expression of p38γ was increased in Et OH and APAP induced liver injury in mice,and overexpression of p38γ resulted in the increased lipid synthesis and secretion of oxidative stress-related factors,silencing p38γ inhibited the expression of Fasn and SREBP-1 in AML-12 cells,indicating p38γmay be related to liver lipid accumulation and oxidative stress.At the same time,in vitro Co-IP results showed that p38γ was expressed in AML-12 cells,and p38γ can bind to Dlg1 and silence p38γ can up-regulate the expression level of Dlg1 protein,which proves p38γ may affect the level of liver lipid accumulation and oxidative stress in Et OH and APAP induced liver injury in mice by binding to Dlg1 protein.Conclusion: these experimental results show that p38γ-deletion reduces ethanol consumption and acetaminophen induced liver injury in mice by promoting Dlg1.