Figure 6. NF-κBregulates SIRP-α expression.

A. Gastrocnemius muscle lysates were obtained from CKD vs. control (CTL) mice. Representative immunoblots of p-IκBα as illustrated (left panel). Band density was measured relative to GAPDH as shown (right panel; *, p<0.05 vs. CTL; n=3). B. C2C12 myoblasts were infected with a NF-κB promoter-luciferase construct. Following their differentiation, the myotubes were treated with the cytokine mixture in serum starved media. Activation of the NF-κB promoter at times listed were measured and the fold change over 0 h was quantified (*, p<0.05 and **, p<0.001 vs. 0 h; n=4 independent experiments). C. Serum starved myotubes were treated with cytokine mixture with or without the NF-κB inhibitor, QNZ. Representative immunoblots of SIRP-α expression (left panel) and band density relative to GAPDH is shown (right panel; *, p<0.05 vs. CTL; n=3 independent experiments). D. C2C12 myoblasts were infected with a DNIKKβ adenovirus or a control-adenovirus that expresses green fluorescent protein (GFP). After differentiation both cell groups were serum starved and treated with cytokines for 24h. Representative western blot analysis (left panel), with quantitative band density of IKKβ and SIRP-α relative to GAPDH as shown (right panel; *, p<0.05 vs. CTL; n=3 independent experiments).