title: [Inhibition of glycogen synthase kinase 3b activity regulates Toll-like receptor 4-mediated liver inflammation].
abstract: OBJECTIVE
  To determine the mechanism underlying the therapeutic activities of glycogen synthase kinase 3b (GSK3b) against hepatic ischemia-reperfusion (H-IR) injury by investigating the inhibitive effects of GSK3b on inflammation mediated by Toll-like receptor 4 (TLR4).
  
  
  METHODS
  C57BL/6 male mice were subjected to 90 min of warm liver cephalad lobe ischemia, followed by reperfusion for various lengths of time. The mice were divided into three groups: the H-IR untreated model (control group), and the H-IR inflammation-induced models that received an intraperitoneal injection of purified lipopolysaccharide (LPS) endotoxin alone (inflammation group) or with pretreatment of the SB216763 GSK3b-specific inhibitor (intervention group). To create a parallel isolated cell system for detailed investigations of macrophages, marrow-derived stem cells were isolated from femurs of the H-IR control group of mice and used to derive primary macrophages. The cells were then divided into the same three groups as the whole mouse system: control, LPS-induced inflammation model, and inflammation model with SB216763 intervention. Differential expressions of inflammation-related proteins and genes were detected by Western blotting and real-time quantitative PCR, respectively.
  
  
  RESULTS
  The phosphorylation levels of ERK, JNK and p38 MAPK were induced in liver at 1 h after reperfusion, but then steadily decreased and returned to baseline levels by 4 h after reperfusion. In addition, the phosphorylation levels of ERK and JNK were induced in macrophages at 15 min after LPS stimulation, while the phosphorylation level of p38 MAPK was induced at 1 h; SB216763 pretreatment suppressed the LPS-stimulated ERK, JNK and p38 phosphorylation in macrophages. In the mouse model, GSK3b activity was found to promote the gene expression of anti-inflammatory cytokine IL-10 (control: 0.21 ± 0.08, inflammation: 0.83 ± 0.21, intervention: 1.76 ± 0.67; F = 3.16, P = 0.027) but to significantly inhibit the gene expression of pro-inflammatory cytokines IL-12 (control: 0.11 ± 0.05, inflammation: 0.85 ± 0.11, intervention: 0.43 ± 0.10; F = 2.67, P = 0.038), TNF-a, (control: 0.052 ± 0.012, inflammation: 8.11 ± 0.98, intervention: 3.9 ± 0.82; F = 4.13, P = 0.016), IL-6 (control: 0.22 ± 0.08, inflammation: 6.37 ± 0.81, intervention: 2.11 ± 0.63; F = 3.21, P = 0.024), and IL-1b (control: 0.12 ± 0.07, inflammation: 2.51 ± 0.62, and intervention: 1.28 ± 0.33; F = 2.22, P = 0.030).
  
  
  CONCLUSIONS
  Inhibition of GSK3b selectively regulates the expression of anti-inflammatory and pro-inflammatory cytokines in liver Kupffer cells (liver macrophages). This process may be one of the mechanisms underlying the ability of GSK3b to ameliorate hepatic ischemia-reperfusion injury, possibly because inhibition of pro-inflammatory cytokines may indirectly mediate liver cell apoptosis.
authors.affiliation: Beijing Institute of Liver Disease, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Ren
authors.forename: Hai-yan
authors.initials: HY
authors.lastname: Zhang
authors.forename: Zheng-fu
authors.initials: ZF
authors.lastname: Piao
authors.forename: Su-jun
authors.initials: SJ
authors.lastname: Zheng
authors.forename: Yu
authors.initials: Y
authors.lastname: Chen
authors.forename: De-xi
authors.initials: DX
authors.lastname: Chen
authors.forename: Zhong-ping
authors.initials: ZP
authors.lastname: Duan
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D007249:Inflammation / Q000378:metabolism* / Q000473:pathology; D008070:Lipopolysaccharides / Q000009:adverse effects; D008099:Liver / Q000473:pathology*; D008264:Macrophages / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D015427:Reperfusion Injury; D051197:Toll-Like Receptor 4 / Q000378:metabolism*
chemical_list: D016207:Cytokines; D008070:Lipopolysaccharides; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D000071679:Glycogen Synthase Kinase 3 beta; C000605507:Gsk3b protein, mouse; D038362:Glycogen Synthase Kinase 3