Interaction of Apoptotic Cells with Macrophages Upregulates COX-2/PGE2 and HGF Expression via a Positive Feedback Loop
Figure 1
Apoptotic cells induce COX-2 expression by RAW 264.7 cells. RAW 264.7 cells were stimulated by UV-exposed apoptotic (ApoJ) or viable (ViaJ) cells of Jurkat T cells (a, b, f, g, i); UV-exposed (ApoN) or aged apoptotic (AgeN) or viable cells of neutrophils (c); UV-exposed apoptotic or viable cells of HeLa cells (ApoH, ViaH) (d); UV-exposed apoptotic or viable cells of thymocytes (ApoT, ViaT) (e) for the time indicated. (a–e) COX-2 or COX-1 mRNA levels were analyzed by semiquantitative RT-PCR and normalized to -actin mRNA levels. (c) COX-2 mRNA levels were normalized to -actin mRNA levels after standardization of the amount of ApoN and AgeN cells. (f–h) Immunoblots with anti-COX-2 or COX-1 antibodies were performed using cultured cell lysates. Relative values of COX-2 or COX-1 expression are indicated below the bands. (h) RAW cells were pretreated with 10 μg/mL actinomycin D (AcD) or 10 μg/mL cycloheximide (CHX) for 1 h before stimulation with ApoJ. Values represent mean ± SEM of three or more separate experiments; . (i) Immunofluorescence staining (green) for COX-2 in RAW cells. Images were captured at ×800 magnification. Representative results from three separate experiments are shown.
