Figure 5

Phosphorylation of SMAD2 and down-regulation of CCL5 are involved in the attenuation of Aβ-induced microglial clustering by TGF-β1. BV-2 cells were treated with SB431542 for 1 h prior to the addition of TGF-β1. Subsequently, BV-2 cells were incubated with Aβ. The number of clusters was quantified (A). Representative western blot analysis of phospho-SMAD2 after the addition of TGF-β1 for different durations and the inhibitory effect of SB431542 on SMAD2 phosphorylation (B). The relative intensities of phospho-SMAD2 compared to control were analyzed (C). The levels of CCL2 and CCL5 mRNA in BV-2 cells after different treatments were compared by real-time PCR (D). ELISA kits were used to measure the levels of CCL2 and CCL5 in the medium of BV-2 cells after different treatments (E). The effects of SB431542 on the down-regulation of CCL5 mRNA levels after TGF-β1 treatment were analyzed (F). Bars represent the mean ± SEM. All of the data were collected from three independent experiments. * = p < 0.05.