Figure 3. PL402 promotes the expression of MMP3 and MMP9 which are involved in the effect of PL402 on Aβ level modulation. (A) The mRNA level of Aβ degradation enzymes (MMPs) in SK-N-SH cells treated by vehicle (0.1% DMSO) or PL402 at 100μM and 300μM for 24h. N=4. (B–C) Representative image of a western blot showing the expression of MMP3 and MMP9 in SK-N-SH cells after treatment with vehicle (0.1% DMSO), or PL402 at 100μM and 300μM for 24h. Actin was used as a loading control (B). (C) The quantification analysis of (B) using ImageJ. N=3. (D) The mRNA level of MMP3 and MMP9 in SK-N-SH cells with the infection of scrambled, MMP3 or MMP9 gene-specific shRNA. N=4. (E) The levels of total Aβ produced by SK-N-SH cells measured by ELISA after treatment with vehicle (0.1% DMSO) or PL402 at 100μM and 300μM for 24 h in the cells infected with scrambled, MMP3 or MMP9 gene-specific shRNA. N=4. (F) The total Aβ level in SK-N-SH cells with presence or absence of the PL402 for 24h after pretreatment with vehicle (0.1% DMSO), or 10μM MMP inhibitor (batimastat) for 1h. N=3. Data are presented as the mean ± SEM, n >3 independent experiments. *p<0.05, **p<0.01, ***p<0.001 compared to the control of each group or the control of the shNC group. One-way ANOVA or two-way ANOVA followed by Bonferroni test.