title: Inhibition of sphingosine kinase 1 ameliorates acute liver failure by reducing high-mobility group box 1 cytoplasmic translocation in liver cells.
abstract: OBJECTIVE
  To determine the therapeutic potential of sphingosine kinase 1 (Sphk1) inhibition and its underlying mechanism in a well-characterized mouse model of D-galactosamine (D-GalN)/lipopolysaccharide (LPS)-induced acute liver failure (ALF).
  
  
  METHODS
  Balb/c mice were randomly assigned to different groups, with ALF induced by intraperitoneal injection of D-GaIN (600 mg/kg) and LPS (10 μg/kg). The Kaplan-Meier method was used for survival analysis. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels at different time points within one week were determined using a multi-parametric analyzer. Serum high-mobility group box 1 (HMGB1), tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, IL-10, and sphingosine-1-phosphate were detected by enzyme-linked immunosorbent assay. Hepatic morphological changes at 36 h after acute liver injury induction were assessed by hematoxylin and eosin staining. HMGB1 expression in hepatocytes and cytoplasmic translocation were detected by immunohistochemistry. Expression of Sphk1 in liver tissue and peripheral blood mononuclear cells (PBMCs) was analyzed by Western blot.
  
  
  RESULTS
  The expression of Sphk1 in liver tissue and PBMCs was upregulated in GalN/LPS-induced ALF. Upregulated Sphk1 expression in liver tissue was mainly caused by Kupffer cells, the resident macrophages of the liver. The survival rates of mice in the N,N-dimethylsphingosine (DMS, a specific inhibitor of SphK1) treatment group were significantly higher than that of the control group (P < 0.001). DMS treatment significantly decreased the levels of serum ALT and AST at 6, 12, and 24 h compared with that of the control group (P < 0.01 for all). Serum HMGB1 levels at 6, 12, and 24 h, as well as serum TNF-α, IL-6, and IL-1β levels at 12 h, were significantly lower in the DMS treatment group than in the control group (P < 0.01 for all). Furthermore, hepatic inflammation, necrosis, and HMGB1 cytoplasm translocation in liver cells were significantly decreased in the DMS treatment group compared to the control group (43.72% ± 5.51% vs 3.57% ± 0.83%, χ(2) = 12.81, P < 0.01).
  
  
  CONCLUSIONS
  Inhibition of SphK1 ameliorates ALF by reducing HMGB1 cytoplasmic translocation in liver cells, and so might be a potential therapeutic strategy for this disease.
authors.affiliation: Yan-Chang Lei, Department of Infectious Diseases, Zhejiang Hospital, Hangzhou 310013, Zhejiang Province, China.
authors.forename: Yan-Chang
authors.initials: YC
authors.lastname: Lei
authors.affiliation: Yan-Chang Lei, Department of Infectious Diseases, Zhejiang Hospital, Hangzhou 310013, Zhejiang Province, China.
authors.forename: Ling-Ling
authors.initials: LL
authors.lastname: Yang
authors.affiliation: Yan-Chang Lei, Department of Infectious Diseases, Zhejiang Hospital, Hangzhou 310013, Zhejiang Province, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Li
authors.affiliation: Yan-Chang Lei, Department of Infectious Diseases, Zhejiang Hospital, Hangzhou 310013, Zhejiang Province, China.
authors.forename: Pan
authors.initials: P
authors.lastname: Luo
authors.affiliation: Yan-Chang Lei, Department of Infectious Diseases, Zhejiang Hospital, Hangzhou 310013, Zhejiang Province, China.
authors.forename: Pei-Fen
authors.initials: PF
authors.lastname: Zheng
mesh_terms: D000818:Animals; D056486:Chemical and Drug Induced Liver Injury / Q000201:enzymology / Q000473:pathology / Q000517:prevention & control*; D003593:Cytoplasm / Q000378:metabolism; D019610:Cytoprotection; D004195:Disease Models, Animal; D015536:Down-Regulation; D005688:Galactosamine; D024243:HMGB1 Protein / Q000378:metabolism*; D007728:Kupffer Cells / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D008099:Liver / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D017114:Liver Failure, Acute / Q000139:chemically induced / Q000201:enzymology / Q000473:pathology / Q000517:prevention & control*; D008297:Male; D008807:Mice, Inbred BALB C; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000037:antagonists & inhibitors* / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D021381:Protein Transport; D015398:Signal Transduction / Q000187:drug effects; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D013997:Time Factors; D000099157:Sphingosine Kinase
chemical_list: D005688:Galactosamine; D024243:HMGB1 Protein; D017853:Phosphotransferases (Alcohol Group Acceptor); D047428:Protein Kinase Inhibitors; D013110:Sphingosine; D000099157:Sphingosine Kinase; C582808:HMGB1 protein, mouse; C061800:N,N-dimethylsphingosine
keywords: Acute liver failure; Cytoplasmic translocation; High-mobility group box 1; Inflammatory cytokine; Sphingosine kinase 1