Group VIB Phospholipase A₂ Promotes Proliferation of INS-1 Insulinoma Cells and Attenuates Lipid Peroxidation and Apoptosis Induced by Inflammatory Cytokines and Oxidant Agents

Figure 1

Influence of the inflammatory cytokines interleukin-1β (IL-1β) and interferon-γ (IFN-γ) on iPLA ₂γ expression by INS-1 cells. Control INS-1 cells were incubated with vehicle alone or with various concentrations of IL-1β and IFN-γ for 16 hr, and iPLA₂γ mRNA levels were then determined by quantitative PCR (panel (a)) and iPLA₂γ protein levels by Western blotting (panel (b)), as described in Experimental Procedures. In panel (c), control INS-1 cells were incubated with IL-1β (5 ng/mL) and IFN-γ (80 ng/mL) for various intervals (0, 8, 16, 24, and 48 hr), at the end of which iPLA₂γ mRNA levels were determined by quantitative PCR. In panels (a) and (c), mean values ± SEM (𝑛=4) are displayed, and an asterisk (*) indicates a significant difference (𝑃<0.05) from the condition in which the concentration (panel (a)) or time (panel (b)) parameter value was zero. The immunoblot in panel (b) is representative of four experiments.

(a) Concentration dependence of cytokine effects on iPLA₂γ mRNA

(b) Concentration dependence of inflammatory cytokine effects on iPLA₂γ protien

(c) Time course of cytokine effects on iPLA₂γ mRNA