Effects of p65 palmitoylation on gene expression when overexpressing vector or p65 WT or p65 2CS in p65 knockout 293A cells combined with TNFα treatment

Nuclear factor kappa B (NF-κB) is a central regulator of inflammation, infection, and immunity pathways and is often dysregulated in autoimmune diseases, inflammatory disorders, and cancers. However, the mechanisms by which different stimuli, including cellular metabolism, modulate NF-κB activation remain unclear. Here, we report that RelA ( p65), a major component of NF-κB, is S-palmitoylated at cysteine 197 and 206 by directly reacting with palmitoyl-CoA. Autopalmitoylation of p65 promotes its nuclear localization and p65-p50 complex formation, thereby enhancing NF-κB transcriptional activities. Furthermore, p65 palmitoylation upregulates RelB expression and promotes non-canonical NF-κB complex formation, further amplifying pathway activation. We also demonstrate that a high-fat diet could enhance p65 palmitoylation and correlate with an increased cytokine production in mouse tissues. These results reveal that lipid metabolism might directly regulate NF-κB activity and suggest that targeting p65 auto-palmitoylation could be a potential therapeutic strategy for diseases with deregulated NF-κB pathway.