The Role Of MTOR Signaling Pathway In Acetaminophen(APAP) Induced Liver Injury

Background Acetaminophen(APAP)overdose is the main cause of acute liver failure in the United States and Europe and can even lead to death.It is a widely used antipyretic and analgesic drug.At therapeutic doses APAP is a safe drug,but an overdose can cause severe liver injury and even acute liver failure in animals and man.Our previous study demonstrated that APAP overdose induces autophagy in the liver,pharmacologic activation of autophagy with rapamycin,an m TOR inhibitor,protects against acetaminophen(APAP)-induced hepatotoxicity,whereas inhibition of autophagy with chloroquine exacerbates this toxicity in mice.These results suggest that autophagy plays a critical role in the physiologic response to APAP overdose.However,the role of m TOR signaling pathway in Acetaminophen(APAP)induced liver injury is unclear.Our project focused on the role of m TOR in Acetaminophen(APAP)induced liver injury,and determined the further mechanism.Objective To investigate the role of m TOR signaling pathway in Acetaminophen(APAP)induced liver injuryMethods 1.Mices including WT mice,L-m TOR-/-mice L-Raptor-/-mice as well as L-TSC1-/-mice are treated APAP to induce liver injury;2.Serum level of alanine aminotransferase(ALT)to assess liver injury;3.Detect GSH in liver;4.hematoxylin and eosin(H&E)staining was used to observe hepatic pathological changes,liver apoptosis was observed by TUNEL staining,The expression of PCNA was detected by immunohistochemistry to show cell proliferation;5.Western blot was used to detect CYP2E1 and APAP Adducts protein level in liver tissues for APAP metabolism,LC3 and P62 protein level for autophagy,JNK and p-JNK protein level for apoptosis.Results Mices were treated by APAP to induce liver injury,we found that m TOR genetic inhibition increased survival rate and decreased ALT slightly,histology showed liver injury.To determine the further mechanism,m TOR genetic inhibition could lead to increased autophagy,but impair liver regeneration,in addition,liver-specific deletion of m TOR could induce more JNK activation.To explore the role of m TOR in APAP induced liver injury further,we deleted TSC1 to activate m TOR,we found that genetic activation of m TOR increased ALT and aggravated the liver injury,but survival rate also increased.There was not too much changes about autophagy,JNK protein could increase by time dependent way.Conclusion m TOR genetic inhibition could lead to increased autophagy,but impair liver regeneration and induce more JNK activation,which alleviated APAP-induced liver injury slightly and increase survive rate.