Figure 2.

CD147 promotes MMP9 biosynthesis during meibocyte differentiation. (a) By phase-contrast microscopy, cultured meibocytes in serum-free media proliferated and had cobblestone-like morphology, whereas addition of serum induced differentiation and stratification. When grown in serum-free media, CD147 had a continuous pericellular distribution (red) while MMP9 (green) was primarily intracellular. Addition of serum promoted a discontinuous pattern of CD147 staining along the cell membrane that colocalized with areas that were positive for MMP9 (inset). Nuclei were counterstained using DAPI (blue). Scale bars, 200 μm (phase), 100 μm (immunofluorescence). (b) Immunoblot showing increased levels of MMP9 in whole cell lysates after addition of serum to cell cultures. Levels of CD147, on the other hand, decreased upon serum-induced differentiation. Data shown are representative of two independent experiments and the experiments were performed at least in duplicate (mean±S.D.; **P<0.01, Student's t-test). (c) Biosynthesis of MMP9 decreased in differentiated meibocytes following abrogation of CD147 using siRNA. Data shown are representative of two independent experiments and the experiments were performed at least in duplicate (mean±S.D.; *P<0.05, Student's t test)