ADAMTS1 (a disintegrin and metalloproteinase with thrombospondin motifs 1) is a member of the matrix metalloproteinase family. We have previously reported that ADAMTS1 was strongly expressed in myocardial infarction. In this study, we investigated whether hypoxia induced ADAMTS1 and investigated its regulatory mechanism. In hypoxia, the expression level of ADAMTS1 mRNA and protein rapidly increased in endothelial cells, but not in other cell types. Interestingly, the induction of ADAMTS1 by hypoxia was transient, whereas vascular endothelial growth factor induction by hypoxia in human umbilical vein endothelial cells (HUVEC) increased in a time-dependent manner. CoCl 2 , a transition metal that mimics hypoxia, induced ADAMTS1 in HUVEC. The phosphatidylinositol 3-kinase inhibitor LY294002 dose-dependently inhibited the increase of ADAMTS1 mRNA expression in hypoxia. We characterized the promoter region of ADAMTS1, and the secreted luciferase assay system demonstrated that hypoxia induced luciferase secretion in the culture medium 4.6-fold in HUVEC. In the promoter region of ADAMTS1, we found at least three putative hypoxiainducible factor (HIF) binding sites, and the chromatin immunoprecipitation assay revealed HIF-1 binding to HIF binding sites in the promoter region of ADAMTS1 under hypoxia. Recombinant ADAMTS1 protein promoted the migration of HUVEC under hypoxic conditions. In summary, we found that ADAMTS1 is transiently induced by hypoxia in endothelial cells, and its transcription is mediated by HIF-1 binding. Our data indicate that ADAMTS1 is a novel acute hypoxia-inducible gene.ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs) is a newly discovered matrix metalloproteinase with multiple domains, including propeptide, metalloproteinase, disintegrin, and spacer region domains, and domains containing thrombospondin type I motifs (1). The ADAMTS family now contains 19 members. One of the best characterized biological functions of ADAMTS is proteolytic activity against extracellular matrix proteins, including proteoglycans (2, 3). In arthritic cartilage, aggrecan breakdown, mediated by members of ADAMTS, not matrix metalloproteinases, is one of the features of the progressive stage. ADAMTS5 (aggrecanase-2) null mice show protection against experimental arthritis (4, 5).ADAMTS1 was originally cloned from a murine colon carcinoma cell line (6). Recently, it has been reported that a polymorphism of ADAMTS1 is closely associated with the occurrence of ischemic heart disease (7). In the cardiovascular system, ADAMTS1 plays roles in atherosclerosis by degrading versican (8) and TFPI-2 (tissue factor pathway inhibitor-2) (9). We have previously reported that ADAMTS1 was induced in the infarcted heart (10); however, the regulatory mechanism of ADAMTS1 in ischemia is unknown.Low oxygen tension (hypoxia) affects endothelial cells in a number of ways, including the transcriptionally regulated expression of vasoactive substances and matrix proteins (11). One mechanism of the regulation of gene expre...