PGRN is cleaved by macrophage elastase MMP-12 in human microglia.
(A) Microglia were incubated with medium alone (control) or LPS for 24 h. Culture supernatants were concentrated ∼25 fold using a 3 kDa cutoff filter. Equal amounts (30 µg) of protein from cell lysates and culture supernatants were loaded in each lane. Blots were probed for PGRN using a C-terminal specific antibody, and for MMP-12 and β-actin. Data are representative of three independent experiments with similar results. (B) Microglia cultures were examined for MMP-12 mRNA expression by Q-PCR (6 h stimulation). Pooled normalized data from 3 different cases are shown. ** p<0.01, ***p<0.001.