title: Expression of stromelysin-3 (matrix metalloproteinase-11) in macrophages of murine thymus following thymocyte apoptosis.
abstract: High expression of stromelysin-3 (ST-3), also known as matrix metalloproteinase-11, has been implicated in tumor progression and intense tissue remodeling. Nonetheless, details of the cell type(s) expressing ST-3 are less well defined. Here, we report that ST-3 expression was elevated in mouse thymus following thymocyte apoptosis after administration of anti-CD3 Ab. TUNEL analysis revealed that many thymocytes in the cortical region were induced to apoptotic cell death 14 h after the injection. After an additional 2-6 h, ST-3 expression in the thymus was more apparent. Co-staining analysis by anti-ST-3 and F4/80 Abs showed that most F4/80-positive macrophages were also positive for ST-3. Murine peritoneal macrophages were found to constitutively express ST-3, and exposure to apoptotic cells hardly affected ST-3 expression in the macrophages. Taken together, our results indicate that ST-3 is not involved in the execution process of thymocyte apoptosis, and the increased levels of ST-3 in the thymus may be due to the presence of macrophages responsible for clearance of apoptotic cells.
authors.affiliation: Department of Safety Research on Blood and Biological Products, National Institute of Infectious Diseases, Tokyo, Japan. odaka@nih.go.jp
authors.forename: Chikako
authors.initials: C
authors.lastname: Odaka
authors.forename: Shinji
authors.initials: S
authors.lastname: Izumiyama
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D017209:Apoptosis / Q000276:immunology / Q000502:physiology*; D017252:CD3 Complex / Q000276:immunology; D019013:CD40 Antigens / Q000502:physiology; D002478:Cells, Cultured; D008264:Macrophages / Q000201:enzymology* / Q000276:immunology; D053507:Matrix Metalloproteinase 11; D008666:Metalloendopeptidases / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology; D013950:Thymus Gland / Q000166:cytology / Q000201:enzymology* / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D017252:CD3 Complex; D019013:CD40 Antigens; D053507:Matrix Metalloproteinase 11; D008666:Metalloendopeptidases