4-benzyl-2-methyl-1-2-4-thiadiazolidine-3-5-dione and Sepsis

The serine-threonine protein kinase glycogen synthase kinase (GSK)-3 is involved in the regulation of many cell functions, but its role in the regulation of the inflammatory response is unknown. Here we investigate the effects of GSK-3beta inhibition on organ injury/dysfunction caused by endotoxaemia or severe inflammation in the rat. Rats received either intravenous Escherichia coli lipopolysaccharide (LPS) (6 mg/kg) or LPS (1mg/kg) plus Staphylococcus aureus peptidoglycan (PepG) (0.3mg/kg) or their vehicle (saline). The GSK-3p1 inhibitors TDZD-8, SB415286 (both 1mg/kg, i.v.), and SB216763 (0.6 mg/kg i.v.), or vehicle (10% dimethyl sulfoxide) were administered 30 min before LPS or LPS/PepG. Both endotoxaemia and co-administration of LPS/PepG resulted in multiple organ injury and dysfunction. The GSK-3beta inhibitors attenuated the organ injury/dysfunction caused by LPS or LPS/PepG. GSK-3beta inhibition reduced the Ser536 phosphorylation of nuclear factor (NF)-kappaB subunit p65 and the mRNA expression of NF-kappaB-dependent pro-inflammatory mediators, but had no effect on the NF-kappaB/DNA binding activity in the lung. GSK-3beta inhibition reduced the increase in NF-kappaB p65 activity caused by interleukin (IL)1 in human e mbryonic kidney cells in vitro. We propose that GSK-3beta inhibition may be useful in the therapy of sepsis, shock and other diseases associated with local or systemic inflammation.

Topics: Alanine Transaminase; Aminophenols; Animals; Aspartate Aminotransferases; Blotting, Western; Cells, Cultured; Creatinine; Endotoxemia; Enzyme Inhibitors; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Humans; Indoles; Interleukin-1beta; Kidney; Lipopolysaccharides; Male; Maleimides; Peptidoglycan; Phosphorylation; Rats; Rats, Wistar; Sepsis; Thiadiazoles; Transcription Factor RelA

Insulin reduces morbidity and mortality among critically ill patients, but the molecular mechanisms of its effect remain unknown. Insulin is a well-known inhibitor of glycogen synthase kinase-3, which may play an important role in systemic inflammation and shock. Here we investigate the role of blood glucose and glycogen synthase kinase-3beta inhibition in the protective effect of insulin on the organ injury/dysfunction associated with excessive systemic inflammation.. Prospective, randomized study.. University-based research laboratory.. Eighty-five anesthetized Wistar rats.. Rats received Escherichia coli lipopolysaccharide (1 mg/kg) and Staphylococcus aureus peptidoglycan (0.3 mg/kg) or vehicle intravenously. Insulin (1.4 units/kg intravenously) was administered in the absence or presence of continuous glucose administration (4.5 mg/kg/hr intravenously) either prophylactically or therapeutically. The potent and selective glycogen synthase kinase-3beta inhibitor TDZD-8 (1 mg/kg intravenously) or vehicle (10% dimethyl sulfoxide) was administered either prophylactically or therapeutically.. Coadministration of lipopolysaccharide and peptidoglycan resulted in increases in the serum levels of creatinine (indicator of renal dysfunction), alanine aminotransferase, and aspartate aminotransferase (indicators of liver injury) at 6 hrs. Insulin or TDZD-8 similarly attenuated the organ injury/dysfunction caused by lipopolysaccharide and peptidoglycan when given either prophylactically or therapeutically. Continuous glucose administration had no effect on blood glucose levels or organ injury/dysfunction at 6 hrs. Treatment with insulin or TDZD-8 reduced the plasma levels of the proinflammatory cytokine interleukin-1beta. In vitro, insulin or TDZD-8 caused similar reductions in the nuclear factor-kappaB p65 activity and similar increases in the phosphorylation of Ser9 of glycogen synthase kinase-3beta.. Therapy with insulin or the potent and selective glycogen synthase kinase-3beta inhibitor TDZD-8 reduced the organ injury/dysfunction caused by lipopolysaccharide and peptidoglycan in the rat. We propose that the inhibitory effect of insulin on the activity of glycogen synthase kinase-3beta contributes to the protective effect of insulin against the organ injury/dysfunction caused by excessive systemic inflammation independently of any effects on blood glucose.

Topics: Analysis of Variance; Animals; Blood Glucose; Blood Pressure; Cells, Cultured; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Heart Rate; Hypoglycemic Agents; Inflammation; Insulin; Interleukin-1; Lipopolysaccharides; Male; Peptidoglycan; Prospective Studies; Random Allocation; Rats; Rats, Wistar; Sepsis; Systemic Inflammatory Response Syndrome; Thiadiazoles; Transcription Factor RelA

Sepsis is associated with muscle wasting, mainly reflecting increased muscle proteolysis. Recent studies suggest that inhibition of GSK-3beta activity may counteract catabolic stimuli in skeletal muscle. We tested the hypothesis that treatment of muscles from septic rats with the GSK-3beta inhibitors LiCl and TDZD-8 would reduce sepsis-induced muscle proteolysis. Because muscle wasting during sepsis is, at least in part, mediated by glucocorticoids, we also tested the effects of GSK-3beta inhibitors on protein degradation in dexamethasone-treated cultured myotubes. Treatment of incubated extensor digitorum longus muscles with LiCl or TDZD-8 reduced basal and sepsis-induced protein breakdown rates. When cultured myotubes were treated with LiCl or one of the GSK-3beta inhibitors SB216763 or SB415286, protein degradation was reduced. Treatment of incubated muscles or cultured myotubes with LiCl, but not the other GSK-3beta inhibitors, resulted in increased phosphorylation of GSK-3beta at Ser9, consistent with inactivation of the kinase and suggesting that the other inhibitors used in the present experiments inhibit GSK-3beta by phosphorylation-independent mechanisms. The present results suggest that GSK-3beta inhibitors may be used to prevent or treat sepsis-induced, glucocorticoid-regulated muscle proteolysis.

Topics: Animals; Cells, Cultured; Dexamethasone; Dose-Response Relationship, Drug; Enzyme Inhibitors; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Lithium Chloride; Male; Muscle Fibers, Skeletal; Muscle Proteins; Muscle, Skeletal; Rats; Rats, Sprague-Dawley; RNA, Messenger; Sepsis; SKP Cullin F-Box Protein Ligases; Thiadiazoles; Tripartite Motif Proteins; Ubiquitin-Protein Ligases