A novel function of tissue inhibitor of metalloproteinase-1 as a chemoattract molecule for neural stem cells

Abstract

Recently neural stem cells (NSCs) were reported to migrate to damaged brain area, such as brain tumor or ischemic region. So, we hypothesized that human glioma or ischemic tissues secreted chomoattract molecules that induce NSC migration toward that area. In present study, we reported one candidate protein, TIMP-1, commonly expressed from microarray and proteomic data. Imuunostaining showed that expression of TIMP-1 is up-regulated in all glioma tissues compared to normal brain tissues. In addition, TIMP-1 dramatically induced migration of NSCs, but not NIH3T3 cells in a does-dependent manner, and showed the maximum activity at a concentration of 100mg/ml. This induction of NSC-specific migration may be derived from the difference of TIMP-1 receptor expression because F3 highly expressed all TIMP-1 receptors, but NIH3T3 cells do not. After then, to investigate if CD63, one of TIMP-1 membrane receptors, mediate NSC migration by TIMP-1 on the cell surface, we established CD63-knockdown F3 cell lines using a vector-based small hairpin RNA (shRNA) strategy. Interestingly, CD63 knockdown blocked almost all NSC migration by TIMP-1 in vitro migration assays. In addition, TIMP-1-mediated migration mediated through ERK and Cdk5 signaling pathway, as PD98059 and roscovitin reduced the migration by 26% and 45%, respectively. All these results demonstrated that TIMP-1 is a powerful chemoattract molecule for NSC, and may be promising drug for brain tumor therapy.