Figure 4.

Ectopic overexpression of NF-κB component proteins and stimulation of cells with 18:1 LPA increases LPP3 protein, enzymatic activity, and mRNA levels. A–H, LPA18:1 treatment increases the levels of RelB (A) and LPP3 protein (B) in a DISP fraction and LPP3 mRNA levels (C and D) in PMA-differentiated THP-1 cells. Increases in LPP3 protein (D and E) and PLPP3 mRNA levels (F and G) in HEK293 cells were also observed after ectopic overexpression of P50/RelA or P52/RelB. Quantification of mRNA expression (D and G) depicts mean normalized ratio values ± S.D. from three independent experiments. LPA 18:1 treatment increases LPP activity in the detergent-extractable membrane protein fraction from PMA-differentiated THP-1 cells, and this increase is blocked by pretreatment of the cells with the NF-κB inhibitor parthenolide (H). The p values were calculated using an ordinary one-way ANOVA with Tukey's multiple comparisons test where necessary. ***, p ≤ 0.001. DSP, detergent-soluble particulate.