Acetaminophen (APAP) overdose is the most common cause of Acute Liver Failure (ALF). Following APAP overdose, toxicity is initiated by the conversion of APAP to its reactive metabolic N‐acetyl‐p‐benzoquinone imine (NAPQI) by CYP2E1/CYP3A4. NAPQI binds covalently to mitochondrial proteins forming 3‐(cysteine‐S‐yl)‐acetaminophen (APAP‐Cys). This generates initial hepatotoxicity in the form of centrilobular necrosis and sterile inflammation. Lipocalin‐2 (LCN2), is an acute‐phase innate immune protein, upregulated during tissue injury in various organs including the liver. Recently we have demonstrated that LCN2 is pro‐inflammatory and elevated during APAP overdose in mouse model. Interestingly, LCN2 knockout (LCN2 KO) mice exhibit protection from APAP overdose compared to its wild type (WT) littermates. During APAP overdose there is necrosis of hepatocytes, these hepatocytes release Damage Associated Molecular Patterns (DAMPS) that further exacerbate the inflammatory process. One such DAMP is High Mobility Group Box 1 (HMGB1). However, the role of LCN2 and HMGB1 in APAP overdose has not yet been investigated. Present study investigates the molecular mechanism of LCN2 during the progression of acute liver injury in APAP overdose model. We hypothesize that during APAP induced ALF, LCN2 induces the expression and translocation of HMGB1 which in turn mediates inflammation and progression of injury. An in vitro model of HepG2 cells as well as an in vivo model of WT and LCN2 KO mice will be utilized to test our hypothesis. HepG2 cells will be treated with recombinant LCN2 to investigate whether exogenous LCN2 can cause induction and translocation of HMGB1. Translocation of HMGB1 will be assessed by immunofluorescence staining. Serum and tissues samples of WT and LCN2 KO mice subjected to APAP overdose will be assessed for expression of HMGB1. APAP‐cys formation will be measured in WT and LCN2 KO using the High‐Performance Liquid Chromatography method to ensure comparable bioactivation based injury between the WT and LCN2 KO mice. Lastly, histopathology will be performed on liver samples from both groups to assess liver pathology. It is anticipated that LCN2 mediates progression of liver injury in APAP overdose via HMGB1. Support or Funding Information Philadelphia College of Osteopathic Medicine‐Division of Research This is from the Experimental Biology 2018 Meeting. There is no full text article associated with this published in The FASEB Journal.