Figure 5

ApoC-I suppresses TLR-dependent activation of primary astrocytes. Cultured WT primary murine astrocytes were treated with 20 μg/ml PIC or 100 ng/ml LPS for 18 h in the presence or absence of 1 μM apoC-I and supernatant amounts of (A) IL-6 and (B) TNF-α (ng/μg protein) quantified by ELISA. ApoC-I significantly reduced PIC and LPS stimulated cytokine release from cultured astrocytes. Unstimulated vehicle controls were below the level of detection (data not shown). Data are expressed as mean ± standard error of the mean (SEM cytokine amount; n = 3 to 6. ***P < 0.001, analysis of variance (ANOVA) with Bonferroni’s multiple comparison test. (C,D) RAP significantly reversed apoC-I suppression of PIC-stimulated secretion of IL-6 and TNF-α by astrocytes. WT astrocytes were treated with 20 μg/ml PIC for 18 h in the presence of apoC-I (1 μM) and/or RAP (1 μM) and cytokine secretion measured by ELISA. Unstimulated vehicle controls were below the level of detection, and treatment with RAP alone did not stimulate cytokine release (data not shown). Data are expressed as mean ± SEM percentage of maximum PIC stimulation; n = 3. **P < 0.01; ***P < 0.001; ANOVA with Bonferroni’s multiple comparison test.