Exposure of astrocytes to PDGF BB resulted in a time dependent in crease of p65 subunit of NF��B in the nucleus with a concomitant selleck compound transient increase in cytosolic pI��B. Validation of the role of NF��B was further determined by pretreating astrocytes with the I��B path way inhibitor, followed by PDGF BB treatment for 24 h. As shown in Figure 6B, SC514 inhibited PDGF BB mediated induction of MCP 1, thereby underscoring the role of NF��B in this process. To corroborate the findings found using the pharma cological inhibitors these cells were then transduced with either WT or DN adenoviral constructs Inhibitors,Modulators,Libraries of NF��B. As shown in Figure 6C, transduction with DN form of NF��B resulted in inhibition of PDGF BB mediated in duction of MCP 1. Transduction with the WT NF��B construct, however, and as expected, demonstrated PDGF BB mediated induction of MCP 1.
Together, these findings underpin the role of NF��B in PDGF BB mediated induction of MCP 1 in astrocytes. Since NF��B is a transcription factor that mitigates its effects Inhibitors,Modulators,Libraries on target genes by binding to promoter regions, we next sought to confirm the binding of NF��B with MCP 1 promoter in its natural chromatin context by ChIP assay to reveal active sites accessible to NF��B. A172 cells were treated with PDGF BB for 1 h followed by RNA extraction and processed using a ChIP analysis kit. These experiments revealed increased binding of NF��B to the MCP 1 promoter in A172 cells treated with PDGF BB and, along with preceding data, substantiate the role of NF��B in PDGF BB mediated regulation of MCP 1 in astrocytes.
MAPK and PI3KAkt cell signaling Inhibitors,Modulators,Libraries pathways lie upstream of PDGF BB induced NF��B in Inhibitors,Modulators,Libraries astrocytes Having determined the involvement of ERK12, JNK and p38 MAPKs and NF��B in Inhibitors,Modulators,Libraries PDGF BB mediated MCP 1 the next logical step was to examine whether there existed a link that could tie together the activation of MAP kinase and Akt pathways with NF��B. Astrocytes were transfected with either the WT or DN constructs of MEK prior to PDGF BB treatment as described before. Nuclear fractions were extracted and NF��B phosphorylation was assessed via western blotting. PDGF BB mediated induction of NF��B was attenuated by DN MEK, but not by WT MEK construct. To confirm the role of PI3KAkt in PDGF BB mediated NF��B, A172 cells were transduced with full article adenoviral con structs containing either WT or DN forms of Akt, trea ted with PDGF BB and assessed for NF��B expression. As shown in Figure 7B, cells transduced with DN Akt con struct failed to upregulate NF��B unlike the cells trans duced with the WT Akt construct. These findings thus linked PDGF BB mediated activation of MAP kinase and Akt pathways to the downstream activation of NF��B.