VCPIP1 negatively regulates NF-κB signaling pathways by deubiquitinating and stabilizing Erbin in MDP-stimulated macrophages.

Macrophages are present in all tissues and body compartments under homeostatic physiological conditions. Importantly, they play a key role in pathological inflammatory processes when disturbed. They can quickly produce large amounts of inflammatory cytokines in response to danger signals. Macrophages can recognize muramyl dipeptide (MDP) through nucleotide-binding oligomerization domain (NOD)-like receptors, subsequently activating the NF-κB signaling pathway and producing proinflammatory cytokines. Erbin can bind to NOD2 and inhibit MDP-induced NF-κB activation, thus participating in the regulation of inflammatory response. Stabilizing or enhancing Erbin expression is essential for suppressing inflammatory responses. In this study, we used a deubiquitination enzyme plasmid library to screen for a key deubiquitinase, VCPIP1, which interacts with Erbin and influences its stability through deubiquitination modification. We investigated whether VCPIP1 affects inflammation using MDP-stimulated RAW 264.7 and BMDMs cells. The results showed that VCPIP1 deficiency reduced Erbin expression and increased NF-κB phosphorylation. Additionally, VCPIP1 deficiency promoted the release of inflammatory factors (IL-1β, IL-6, and TNF-α) in RAW 264.7 cells and BMDMs. This study further expands the role of deubiquitinases (DUBs) in inflammation, providing new insights for the prevention and treatment of sepsis, tumors, immune diseases, and other inflammatory reactions.