Matrix metalloproteinase-3 induction in rat brain astrocytes: focus on the role of two AP-1 elements.
Many brain cells secrete MMPs (matrix metalloproteinases), and increased or misregulated MMP levels are found in neurodegenerative disorders. Here we report that MMP-3 transcription and protein secretion were increased in rat brain astrocytes stimulated with lipopolysaccharide, gangliosides or interferon-gamma. Sequential deletion of the MMP-3 promoter revealed that sequences between -0.5 kb and the start codon were crucial for the transcriptional induction of MMP-3. In addition, experiments using pharmacological inhibitors of individual mitogen-activated protein kinases revealed that MMP-3 induction and promoter activity involved Jun N-terminal kinase, a representative upstream signal of AP-1 (activator protein-1). Sequence analyses of the region of the MMP-3 promoter 500 bp from the start codon indicated the presence of three AP-1 binding sequences. Among them, electrophoretic-mobility-shift assays as well as site-directed mutagenesis of individual AP-1 sequences revealed that distal and middle, but not proximal, sequences largely mediated its induction. Together, these results indicate that AP-1 could control MMP-3 induction in brain astrocytes and that its regulation through specific AP-1 elements could be exploited in the treatment of brain pathologies in which increased expression of MMP-3 plays crucial roles.
Kim
Kwang Soo
KS
Department of Pharmacology and Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, Korea 442-721.
Kim
Hee Young
HY
Joe
Eun-Hye
EH
Jou
Ilo
I
D000818:Animals; D001253:Astrocytes / Q000201:enzymology*; D001483:Base Sequence; D015153:Blotting, Western; D001921:Brain / Q000166:cytology / Q000201:enzymology*; D004247:DNA; D017931:DNA Primers; D024202:Electrophoretic Mobility Shift Assay; D004790:Enzyme Induction; D005732:Gangliosides / Q000494:pharmacology; D007371:Interferon-gamma / Q000494:pharmacology; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D019278:Matrix Metalloproteinase 3 / Q000096:biosynthesis* / Q000235:genetics; D011401:Promoter Regions, Genetic; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018808:Transcription Factor AP-1 / Q000502:physiology*; D014158:Transcription, Genetic
D017931:DNA Primers; D005732:Gangliosides; D008070:Lipopolysaccharides; D018808:Transcription Factor AP-1; D007371:Interferon-gamma; D004247:DNA; D048031:JNK Mitogen-Activated Protein Kinases; D019278:Matrix Metalloproteinase 3