Short-Term Regulation of FcγR-Mediated Phagocytosis by TLRs in Macrophages: Participation of 5-Lipoxygenase Products

Figure 5

ERK-1/2 inhibition impairs phagocytic process promoted by TLRs. (a) Mouse PMs were pretreated with TLR2 (Pam3Cys: 25 μg·ml⁻¹), TLR3 (poly I:C: 1 μg·ml⁻¹), or TLR4 (LPS: 1 μg·ml⁻¹) agonists for 1 h, and then challenged with IgG-sRBC (1 : 40 ratio) for further 30 min. Incubations were terminated by addition of lysis buffer, and lysates were subjected to immunoblotting as described in Materials and Methods. Immunoblots in the upper panel represent phosphorylated ERK-1/2, middle panel represents total ERK-1/2, and lower panel, the amounts of GAPDH. Immunoblots are representative of two separate experiments. (b) Mouse PMs were pretreated with medium containing MEK inhibitor (PD98059 25 μM) for 20 min and then treated with TLR2 (Pam3Cys: 25 μg·ml⁻¹), TLR3 (poly I:C: 1 μg·ml⁻¹), or TLR4 (LPS: 1 μg·ml⁻¹) agonists for 1 h. The cells were challenged with RBCs or IgG-RBCs (1 : 40). Results are expressed as the mean ± SEM. Values are presented as the percentage of the IgG-RBC group and the negative control group, and the RBC control group was discounted from all groups. compared to IgG-RBCs group or ^# compared to TLR without PD98059. ^§ compared to the respective TLR without IgG-RBC challenge. Statistical analysis was performed using Student’s t-test. The results of one experiment representative of three independent experiments performed in heptaplicate.

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