5A and B). IκBα was quickly resynthesized in WT macrophages such that near baseline levels were reached after 60 min (Fig. 5A Selleckchem JAK inhibitor and B). In contrast, a consistent trend toward delayed IκBα resynthesis was observed in the absence of β2 integrins (Fig. 5A and B) suggesting an elevation in NF-κB pathway activation in Itgb2−/− macrophages. To assess phosphorylation
of IκBα, we stimulated macrophages in the presence of the proteasomal inhibitor MG-132 to compensate for the rapid degradation of IκBα protein. Both WT and Itgb2−/− cells quickly phosphorylated IκBα, without an increase in phosphorylation in the Itgb2−/− cells over WT cells (Supporting Information Fig. 6A and B). These results were coupled with similar observations at the late phase of TLR stimulation. Itgb2−/− macrophages displayed consistently lower levels of IκBα up to 4 h post-LPS treatment in comparison with WT cells, though the magnitude of this effect was modest (Fig. 5C and D). Itgb2−/− macrophages displayed similar phosphorylation of IκBα at 2 h post LPS treatment to WT macrophages, but this IκBα phosphorylation was slightly increased in Itgb2−/− macrophages over WT macrophages at 4 h post LPS treatment (Supporting Information
Fig. 6C and D). Notably, increases in IκBα degradation in Itgb2−/− macrophages were not due learn more to a defect in IκBα resynthesis in these cells. Itgb2−/− macrophages were able to transcribe IκBα mRNA at or beyond the levels observed for WT macrophages (Fig. 5E and F). Therefore, our data show that β2 integrins can affect the magnitude of the signal Non-specific serine/threonine protein kinase leading to NF-κB activation in the cytoplasm. We thus compared the induction of NF-κB-dependent genes induced during TLR responses in WT and Itgb2−/− macrophages. TLR hyperactivation also generated changes to the NF-κB-dependent gene transcriptional profile of Itgb2−/− macrophages. As expected, β2 integrin-deficient macrophages produced more inflammatory cytokine transcripts
than did WT control cells following TLR stimulation, with the greatest differences observed for IL-12 p40 and IL-6 mRNA (Fig. 6A). Consistent with these observations, Itgb2−/− macrophages also presented with higher levels of mRNA for many NF-κB-dependent genes  as compared to WT, including increases in Bfl-1, CXCL1, CXCL2, CXCL10, and GADD45β (Fig. 6B), indicating a global increase in NF-κB activity without β2 integrin-mediated inhibition. The magnitude of the effect of β2 integrin deficiency varied and a curious exception to this increased gene expression profile was that of iNOS, which directs the antimicrobial nitric oxide responses, the synthesis of which was identical between Itgb2−/− and WT macrophages (Fig. 6B).