title: Up-regulation of matrix metalloproteinase-1 expression in U937 cells by low-density lipoprotein-containing immune complexes requires the activator protein-1 and the Ets motifs in the distal and the proximal promoter regions.
abstract: We reported previously that low-density lipoprotein (LDL)-containing immune complexes (LDL-IC) stimulated matrix metalloproteinase-1 (MMP-1) expression in U937 histiocytes through Fc gamma receptor (FcgammaR)-mediated extracellular signal-regulated kinase pathway. The present study has explored the transcriptional mechanisms involved in the stimulation. Deletion analysis showed that LDL-IC stimulated MMP-1 promoter activity in cells transfected with the Construct 1 that contained a 4,334-bp MMP-1 promoter fragment, but had no effect in cells transfected with other constructs that had shorter MMP-1 promoter (2685-bp or less), suggesting that cis-acting elements located between -4334 and -2685 are required for the promoter stimulation. The mutation study further indicated that the activator protein-1 (AP-1) (-3471) or Ets (-3836) motifs in this distal region were essential for the LDL-IC-stimulated MMP-1 expression. Moreover, although above deletion analysis showed that LDL-IC did not stimulate MMP-1 promoter activity in cells transfected with constructs that contained the proximal AP-1 (-72) and Ets (-88) in the promoter fragments that are 2685-bp or less, the mutations of the -72 AP-1 or the -88 Ets motif in the construct 1 abolished the stimulation of MMP-1 expression by LDL-IC, suggesting that a long promoter sequence is required for the -72 AP-1 and -88 Ets motifs to be involved in the stimulation. Finally, electrophoretic mobility shift assay showed that LDL-IC stimulated the activities of transcription factors AP-1 and Ets. In conclusion, the present study shows that both the distal and proximal AP-1 and Ets motifs are required for LDL-IC-stimulated MMP-1 expression in U937 histiocytes.
authors.affiliation: Division of Endocrinology, Diabetes and Medical Genetics, Department of Medicine, Medical University of South Carolina, Charleston, SC 29403, USA.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Maldonado
authors.forename: Bryan A
authors.initials: BA
authors.lastname: Game
authors.forename: Lanxi
authors.initials: L
authors.lastname: Song
authors.forename: Yan
authors.initials: Y
authors.lastname: Huang
mesh_terms: D000936:Antigen-Antibody Complex / Q000276:immunology*; D001483:Base Sequence; D015152:Blotting, Northern / Q000379:methods; D004247:DNA / Q000032:analysis; D024202:Electrophoretic Mobility Shift Assay / Q000379:methods; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D017353:Gene Deletion; D006801:Humans; D008077:Lipoproteins, LDL / Q000276:immunology*; D020781:Matrix Metalloproteinase 1 / Q000235:genetics* / Q000276:immunology; D009154:Mutation / Q000235:genetics / Q000276:immunology; D011401:Promoter Regions, Genetic / Q000276:immunology*; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000276:immunology; D050783:Proto-Oncogene Proteins c-ets; D018808:Transcription Factor AP-1 / Q000276:immunology*; D014157:Transcription Factors / Q000235:genetics / Q000276:immunology; D014158:Transcription, Genetic; D014162:Transfection; D020298:U937 Cells; D015854:Up-Regulation / Q000276:immunology*
chemical_list: D000936:Antigen-Antibody Complex; D008077:Lipoproteins, LDL; D011518:Proto-Oncogene Proteins; D050783:Proto-Oncogene Proteins c-ets; D018808:Transcription Factor AP-1; D014157:Transcription Factors; D004247:DNA; D020781:Matrix Metalloproteinase 1