Gelatinase A expression in endothelial cells is regulated by at least two cis-acting promoter elements

Increased expression of gelatinase A is associated with both angiogenesis a nd alterations in blood vessel structure, Heart-derived endothelial cells d erived from spontaneously hypertensive rats (SHR) were found to express sig nificantly more gelatinase A in culture, both at the protein and mRNA level , than endothelial cells from normotensive Wistar-Kyoto (WKY) rats. Other m atrix metalloproteinases, as well as their tissue inhibitors, were not diff erentially regulated. A 1683 bp gelatinase A promoter fragment linked to a luciferase reporter demonstrated up to 40-fold more activity when transfect ed into SHR-derived cells Versus WKY-derived cells. The promoter region bet ween -1324 and -1272, previously termed REI, contributed up to a five-fold increase in basal promoter activity in both cells, but contributed only 12% of the promoter activity in SHR-derived cells compared to 85% in WKY-deriv ed cells. In SHR-derived cells, but not in WKY-derived cells, a second regi on between -1435 and -1375, termed RE2, contributed 60% of the total activi ty of the 1683 bp promoter fragment. Both electrophoretic mobility shift as says and Southwestern blots demonstrated differences in RE2-specific bindin g factors in nuclear extracts derived from the two cell types. SHR-derived endothelial cells thus represent a new model system to study the regulation of gelatinase A expression, which itself may contribute to the abnormal va scular structure seen in the SHR. (C) 1999 Elsevier Science B.V. All rights reserved.