Figure 1.

PPM1A is kinetically upregulated during monocyte-to-macrophage differentiation. (A) Primary human CD14⁺ monocytes or (B) THP-1 monocytes were stimulated with GM-CSF (5 ng/ml) or PMA (100 ng/ml) to induce macrophage differentiation, respectively. Cell lysates were prepared at the indicated days post differentiation and PPM1A protein levels were analyzed by Western blotting. Densitometry analysis was performed by ImageJ to quantify PPM1A band intensities as normalized to GAPDH or α-tubulin and fold increase of PPM1A levels are expressed relative to cells prior to differentiation. The fold increase is specific to the representative blot shown. Quantitative real-time PCR was used to measure the relative expression levels of PPM1A mRNA in (C) primary hMDMs at day 0, 3, 6, and 9 post GM-CSF induced differentiation or (D) THP-1 cells at day 0, 1, 3, 5 post PMA-induced differentiation. The ΔΔCT method was used for data analysis using GADPH as a control and the relative fold expression differences was normalized to day 0 as 1.0. Data in C-D represent the means ± S.D. of three independent experiments. *p < 0.01 relative to day 0 control cells.