Figure 1.

PEDF secreted by adipocytes increases macrophage TNF production. (A) Different amounts of 3T3-L1 adipocyte CM was added to RAW cells, and levels of TNF in the cell supernatant were quantitated by ELISA. (B) 3T3-L1 adipocyte CM was fractionated with cation exchange chromatography. (C) RAW cells were cultured with individual fraction, and levels of secreted TNF were quantitated with ELISA. Fold change in TNF levels was determined by calculating the increase in TNF levels in response to the individual fraction compared with medium control. Arbitary units of specific activity were determined as fold change per milligram of total protein. (D) RAW cells were cultured with recombinant PEDF, and RNA was isolated after 60 min. Real-time polymerase chain reaction analysis was carried out as described in the Methods. Data are mean ± standard error (SE), *p < 0.05 and **p < 0.005 versus medium alone control. (E) RAW cells were cultured with recombinant PEDF for 2.5 h, and TNF levels were quantitated in the supernatant by ELISA. Data are mean ± SE, *p < 0.05 and **p < 0.0005 versus medium-alone control.