# SENP6 Restrains NLRP3 Inflammasome Activation via DeSUMOylation-Driven K48-Linked Ubiquitination of NLRP3 in Acute Lung Injury

## TL;DR

SENP6 limits NLRP3 inflammasome activation by modifying it through deSUMOylation and ubiquitination, which could lead to new treatments for inflammatory diseases.

## Contribution

SENP6 is newly identified as a negative regulator of NLRP3 via deSUMOylation and ubiquitination, revealing a novel regulatory mechanism.

## Key findings

- SENP6 deficiency increases NLRP3 activation and secretion of IL-1β and IL-18 in macrophages.
- SENP6 deSUMOylates NLRP3 at K23, K204, and K689, promoting its degradation via autophagy.
- SENP6 deficiency worsens lung inflammation in endotoxic shock and peritonitis in mice.

## Abstract

The NLRP3 inflammasome is a pivotal component of the innate immune system, responding to infections and cellular damage. Its dysregulation has been implicated in numerous inflammatory diseases, although the mechanisms controlling its activation remain incompletely elucidated. Recent studies have highlighted the importance of posttranslational modifications, such as ubiquitination and SUMOylation, in regulating inflammasome activation. In this study, we demonstrate that SENP6, a SUMO-specific protease, negatively regulates NLRP3 inflammasome activation by promoting K48-linked polyubiquitination of NLRP3. SENP6-deficient macrophages exhibit enhanced NLRP3 activation and increased secretion of interleukin-1β (IL-1β) and IL-18, resulting in amplified inflammatory responses. Mechanistically, SENP6 interacts with NLRP3 and promotes its degradation through the autophagy–lysosomal pathway via K48-linked polyubiquitination. We further identified that SENP6 deSUMOylated NLRP3 at specific lysine residues (K23, K204, and K689), which was essential for maintaining NLRP3 stability. Additionally, SENP6 recruits the E3 ubiquitin ligase MARCHF7 to promote NLRP3 ubiquitination and subsequent degradation. In vivo, SENP6 deficiency exacerbates NLRP3 activation and lung inflammation in lipopolysaccharide-induced endotoxic shock-associated lung injury, and enhances inflammatory responses in alum-induced peritonitis. Our findings reveal a novel mechanism whereby SENP6 modulates NLRP3 inflammasome activation via SUMOylation, ubiquitination, and degradation, providing new insights into potential therapeutic strategies for inflammasome-related pathologies.