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

Area of Science:

• Immunology
• Molecular Biology
• Cell Biology

Background:

• Macrophages are crucial immune cells involved in both homeostasis and pathological inflammation.
• Muramyl dipeptide (MDP) activates NF-κB signaling via NOD-like receptors, leading to pro-inflammatory cytokine production.
• Erbin protein inhibits MDP-induced NF-κB activation, suggesting its role in regulating inflammatory responses.

Purpose of the Study:

• To identify deubiquitinating enzymes (DUBs) that regulate Erbin stability and inflammatory signaling.
• To investigate the role of VCPIP1 (a DUB) in modulating Erbin expression and inflammatory responses.

Main Methods:

• Screening of a deubiquitination enzyme plasmid library to identify Erbin-interacting DUBs.
• Utilizing MDP-stimulated RAW 264.7 cells and bone marrow-derived macrophages (BMDMs) to assess VCPIP1's function.
• Analyzing Erbin expression, NF-κB phosphorylation, and inflammatory cytokine release (IL-1β, IL-6, TNF-α).

Main Results:

• VCPIP1 was identified as a key deubiquitinase interacting with Erbin.
• VCPIP1 deficiency led to reduced Erbin expression and increased NF-κB phosphorylation.
• Loss of VCPIP1 enhanced the release of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) in response to MDP.

Conclusions:

• VCPIP1 plays a critical role in regulating inflammatory responses by stabilizing Erbin.
• VCPIP1 deficiency exacerbates inflammation through decreased Erbin levels and enhanced NF-κB activation.
• This study highlights DUBs as potential therapeutic targets for inflammatory diseases such as sepsis and cancer.