Enhanced induction of proinflammatory gene expression by HMGB1/IL-1β complex.

<p>Human THP-1 monocytes were incubated with either recombinant (r) human HMGB1 (4nM, 100ng/mL), recombinant pro-IL-1β (rpro-IL-1β, 4nM) or rHMGB1/r pro-IL-1β complexes. Cell lysates were harvested 24 hours later and analyzed by RT-PCR for expression of immune gene of interest. (A) Neither HMGB1 nor pro-IL-1β alone significantly altered IL-6 mRNA. However, rHMGB1/r pro-IL-1β complexes caused a 2.7-fold increase in IL-6 gene expression (B) Neither HMGB1 nor pro-IL-1β alone significantly altered IFNβ mRNA. rHMGB1/r pro-IL-1β complexes caused a 3.1-fold increase in IFNβ gene expression (C) rHMGB1/rpro-IL-1β caused a 36% reduction in iNOS gene expression, while neither HMGB1 nor pro-IL-1β alone caused changes (D) r-pro-IL-1β caused a 2.5-fold increase in NOX-2 alone. rHMGB1/rIL-1β complexes showed no further increase in NOX-2 gene expression. ***<i>p<</i>0.001, **<i>p</i><0.01, *<i>p</i><0.05 vs control. N = 2–6 culture wells per group.