[Role of PRKCD and ASK1 in U937 cell differentiation]

To investigate the expression of ASK1 and PRKCD in the process of monocyte differentiation, and explore their role in functional changes of hypersplenism spleen macrophages (Mφ) in portal hypertension (PH).

U937 cells were stimulated to differentiate into monocyte/macrophage-like cells by cultivation in PMA and the mRNA expressions of ASK1 and PRKCD were detected by q-PCR and the changes of protein expression were identified by western blot analysis. The secretion of phagocytose related cytokines such as IL-10 and TNF-α were tested by ELISA, and the function of the macrophage-like cells were studied by chicken red blood cell phagocytose test.

The expressions of PRKCD and ASK1 mRNA were gradually decreased along with the cell differentiation, while the secretion of TNF-α was increased, IL-10 secretion reached a maximum at 24 h after PAM stimulation, and then gradually fell. The expression of ASK1 and p-ASK1 were rapidly increased compared with the non-stimulated U937 cells, while the expression of PRKCD and p-PRKCD were sightly declined. The phagocytose test show that U937 cells induced with PMA were able to swallow the chicken red blood cell.

Up-regulated protein expression of ASK1 and p-ASK1 and down-regulated protein expression of PRKCD and p-PRKCD in the process of PMA induced monocyte differentiation, are consist with the expression changes of splenic macrophage phagocytosis in hypersplenism, which leads to increased activity of Mφ.