Glycogen synthase kinase-3β inactivation is an intracellular marker and regulator for endotoxemic neutrophilia.
Neutrophilia, defined as a large number of neutrophils in the circulating blood, is caused by increased differentiation and survival from activation-induced apoptosis. Regulation of apoptosis is essential for neutrophil homeostasis; however, the molecular signaling that regulates this process needs further investigation. Unlike TLR4 wild-type C3H/HeN mice, TLR4 mutated C3H/HeJ mice were insusceptible to LPS-induced blood neutrophilia. LPS prevented constitutive apoptosis in neutrophils and partly involved a blockade of the mitochondrial pathway including mitochondria transmembrane potential loss, myeloid cell leukemia sequence (Mcl) 1 degradation, and caspase-3 activation. In apoptotic neutrophils, glycogen synthase kinase (GSK)-3β was activated, and inhibiting GSK-3β decreased Mcl-1 degradation and apoptosis. LPS caused p38 MAPK-, JNK-, and PI3K/AKT-mediated Mcl-1 stabilization and prevented apoptosis, and LPS induced GSK-3β inactivation mainly through p38 MAPK and PI3K/AKT. Neutrophils in the neutrophilia showed increased GSK-3β inactivation and Mcl-1 stabilization accompanied by activation of p38 MAPK, JNK, and AKT. Notably, LPS-induced ROS generation can partly facilitate p38 MAPK/JNK/AKT activation to regulate GSK-3β-mediated Mcl-1 stability, apoptosis, and neutrophilia. These results demonstrate that the molecular basis of endotoxemic neutrophilia is through a direct action on neutrophils involving GSK-3β inactivation to prevent constitutive apoptosis.
Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
Tsan-Tzu
TT
Yang
Chia-Ling
CL
Chen
Wei-Chieh
WC
Lin
Yee-Shin
YS
Lin
Po-Chun
PC
Tseng
Chia-Yuan
CY
Hsieh
Yu-Hong
YH
Chen
Wei-Ching
WC
Huang
Cheng-Chieh
CC
Tsai
Chi-Yun
CY
Wang
Chi-Chang
CC
Shieh
Chiou-Feng
CF
Lin
D000818:Animals; D002478:Cells, Cultured; D019446:Endotoxemia / Q000276:immunology*; D038362:Glycogen Synthase Kinase 3 / Q000276:immunology*; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D007958:Leukocyte Count; D007960:Leukocyte Disorders / Q000276:immunology*; D008070:Lipopolysaccharides; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009504:Neutrophils / Q000276:immunology*; D011494:Protein Kinases / Q000276:immunology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000276:immunology; D051197:Toll-Like Receptor 4 / Q000276:immunology
D008070:Lipopolysaccharides; C579094:Mcl1 protein, mouse; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D019253:Proto-Oncogene Proteins c-bcl-2; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D011494:Protein Kinases; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; C000605507:Gsk3b protein, mouse; D038362:Glycogen Synthase Kinase 3