GATA-2 transduces LPS-induced il-1β gene expression in macrophages via a toll-like receptor 4/MD88/MAPK-dependent mechanism.
Lipopolysaccharide (LPS) is a critical factor for inducing acute lung injury. GATA-2, a transcription factor, contributes to the control of cell activity and function. Exposure of RAW 264.7 cells to LPS induced interleukin (IL)-1β mRNA and protein expression and GATA-2 translocation from the cytoplasm to nuclei in concentration- and time-dependent manners. A bioinformatic search revealed that GATA-2-specific binding elements exist in the 5'-promoter region of the il-1β gene. LPS could enhance the transactivation activity of GATA-2 in macrophages. Knocking-down translation of GATA-2 mRNA using RNA interference significantly alleviated LPS-induced IL-1β mRNA and protein expression. As to the mechanism, transfection of toll-like receptor (TLR) 4 small interfering (si)RNA into macrophages concurrently decreased LPS-caused increases in nuclear GATA-2 levels. Sequentially, treatment with myeloid differentiation factor 88 (MyD88) siRNA decreased LPS-induced phosphorylation of mitogen-activated protein kinases (MAPKs) kinase 1/2 and subsequent translocation of GATA-2. Reducing MAPK activities using specific inhibitors simultaneously decreased GATA-2 activation. Furthermore, exposure of primary macrophages to LPS significantly increased the transactivation activities of GATA-2 and IL-1β mRNA and protein expression. Transfection of GATA-2 siRNA inhibited LPS-induced IL-1β mRNA expression. Results of this study show that LPS induction of il-1β gene expression in macrophages is mediated by GATA-2 via activation of TLR4, MyD88, and MAPKs.
Graduate Institute of Medical Sciences and Center of Excellent Cancer Research, Taipei Medical University, Taipei, Taiwan.
Tsu-Tuan
TT
Wu
Yu-Ting
YT
Tai
Yih-Giun
YG
Cherng
Tyng-Guey
TG
Chen
Chien-Ju
CJ
Lin
Ta-Liang
TL
Chen
Huai-Chia
HC
Chang
Ruei-Ming
RM
Chen
D000818:Animals; D002478:Cells, Cultured; D050989:GATA2 Transcription Factor / Q000235:genetics / Q000502:physiology*; D005786:Gene Expression Regulation / Q000187:drug effects; D053583:Interleukin-1beta / Q000235:genetics* / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology*; D020935:MAP Kinase Signaling System / Q000502:physiology; D017737:Macrophages, Peritoneal / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D053594:Myeloid Differentiation Factor 88 / Q000502:physiology*; D021381:Protein Transport / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D051197:Toll-Like Receptor 4 / Q000502:physiology*
D050989:GATA2 Transcription Factor; C494712:Gata2 protein, mouse; D053583:Interleukin-1beta; D008070:Lipopolysaccharides; C507780:Myd88 protein, mouse; D053594:Myeloid Differentiation Factor 88; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4