MMP2 and MMP9 are down-regulated in LRP1 deficient cells and brain tissues. Levels of MMP2 and MMP9 mRNA in MEF cells or mouse brain tissues were quantified by real-time PCR. A, mRNA levels of MMP2, MMP9, LRP1, LDLR, and MMP7 in WT MEF1 and LRP1-deficient MEF2 cells. B, mRNA levels of MMP2, MMP9, LRLP1, LDLR, and MMP7 in brain tissues from control and LRP1-forebrain knockout mice. Values are the average of triple determinations with the S.D. indicated by error bars. *p < 0.05, **p < 0.01