Figure 4.

SP110b downregulates tumor necrosis factor-α (TNF-α) production by modulating nuclear factor-κB (NF-κB) activity. (A) Western blot analysis of RELA and NF-κB1 expression in a THP1-enhanced green fluorescent protein (eGFP)-SP110b clonal cell line at 2 and 4 days after treatment. (B) RELA and NFκB1 gene expression in a THP1-eGFP-SP110b clonal cell line was analyzed by quantitative polymerase chain reaction at 2 days post-treatment. (C–E) The relative firefly (F.)/Renilla (R.) luciferase (Luc) values associated with the TNF-α promoter were measured 2 days after transient cotransfection with the pGL3-TNF-α promoter F.Luc, pSV40-R.Luc, and the indicated constructs into HEK293T cells. An empty vector is included in the left column as a negative control. In D, a and b indicate SP110a and SP110b, respectively. Data in B–E are presented as the mean ± SD of three cultures. Statistical significance was calculated using (C and E) nonparametric one-way analysis of variance (Kruskal-Wallis test) or (D) a two-tailed, unpaired t test. *P < 0.05; **P < 0.01; ***P < 0.001. All data represent three independent experiments. Dox = doxycycline; RELA = the gene that encodes NF-κB p65 subunit.