Use of suppression subtractive hybridization strategy for discovery of increased tissue inhibitor of matrix metalloproteinase-1 gene expression in brain ischemic tolerance

Abstract

Brief occlusion of the middle cerebral artery (i.e., ischemic preconditioning; PC) induces significant brain protection to subsequent severe ischemic events. In an effort to discover genes responsible for ischemic tolerance, we have applied a new technique, suppression subtractive hybridization (SSH), to identify genes that are upregulated by PC. Using this SSH approach, a cDNA that encodes tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) was identified. Time course studies using Northern analysis revealed that TIMP-1 mRNA was significantly elevated at 24 hours (3.3-fold over controls, P < 0.05, n = 5) and 2 days (4.3-fold increase, P < 0.01) after PC, corresponding to the onset of significant ischemic tolerance. Our data not only demonstrate the utility of this new polymerase chain reaction-based SSH strategy for discovery of genes differentially expressed in PC, but also suggest a potential role of TIMP-1 in PC-induced ischemic tolerance.