Cell
Volume 164, Issue 5, 25 February 2016, Pages 896-910
Journal home page for Cell

Article
NF-κB Restricts Inflammasome Activation via Elimination of Damaged Mitochondria

https://doi.org/10.1016/j.cell.2015.12.057Get rights and content
Under an Elsevier user license
open archive

Highlights

  • NF-κB mediates LPS-induced p62/SQSTM1 expression in macrophages

  • NLRP3 agonists damage mitochondria and release inflammasome activating signals

  • Ubiquitinated damaged mitochondria are eliminated by p62-dependent mitophagy

  • p62 ablation prevents mitophagy and enhances NLRP3-inflammasome activation

Summary

Nuclear factor κB (NF-κB), a key activator of inflammation, primes the NLRP3-inflammasome for activation by inducing pro-IL-1β and NLRP3 expression. NF-κB, however, also prevents excessive inflammation and restrains NLRP3-inflammasome activation through a poorly defined mechanism. We now show that NF-κB exerts its anti-inflammatory activity by inducing delayed accumulation of the autophagy receptor p62/SQSTM1. External NLRP3-activating stimuli trigger a form of mitochondrial (mt) damage that is caspase-1- and NLRP3-independent and causes release of direct NLRP3-inflammasome activators, including mtDNA and mtROS. Damaged mitochondria undergo Parkin-dependent ubiquitin conjugation and are specifically recognized by p62, which induces their mitophagic clearance. Macrophage-specific p62 ablation causes pronounced accumulation of damaged mitochondria and excessive IL-1β-dependent inflammation, enhancing macrophage death. Therefore, the “NF-κB-p62-mitophagy” pathway is a macrophage-intrinsic regulatory loop through which NF-κB restrains its own inflammation-promoting activity and orchestrates a self-limiting host response that maintains homeostasis and favors tissue repair.

Cited by (0)

10

Co-first author