MK2/p38/p53 Suppress Basal IL-1β and Non-Canonical NF-κB Signaling in Macrophages

Area of Science:

• Immunology
• Molecular Biology
• Cancer Research

Background:

• Interleukin-1β (IL-1β) is a key pro-inflammatory cytokine involved in sterile inflammation and tumor development.
• MAPKAP kinase 2 (MK2) is investigated for its role in regulating IL-1β production.

Purpose of the Study:

• To investigate the role of MK2 in the processing and regulation of IL-1β.
• To elucidate the molecular mechanisms linking MK2, p53, and IL-1β expression.
• To understand the connection between inflammation and cancer through this pathway.

Main Methods:

• Utilized MK2-knockout (KO) and MK2/3 double-KO mouse models.
• Analyzed IL-1β mRNA and protein levels in macrophages and serum.
• Investigated the non-canonical NF-κB pathway activation and the role of p53 and caspase-3.

Main Results:

• Elevated IL-1β levels were observed in resting MK2-KO macrophages and serum of MK2/3 double-KO mice.
• MK2 deficiency or p38α absence activated the non-canonical NF-κB pathway.
• p53 interacts with caspase-3 to cleave RelB, inhibiting NF-κB signaling and IL-1β/TP53 expression.

Conclusions:

• MK2 deficiency leads to increased IL-1β via non-canonical NF-κB pathway activation.
• p53 acts as a negative regulator of IL-1β production and autoregulates its own expression.
• Uncovered a novel mechanism where tumor suppressor p53 inhibits cytokine production, linking inflammation and cancer.