USP48 promotes NLRP3-dependent pyroptosis of alveolar macrophages to exacerbate sepsis-induced acute lung injury

Aijun Jia; Yueling Wang; Rimei Zhou; Likun Han

doi:10.1016/j.intimp.2025.115140

USP48 promotes NLRP3-dependent pyroptosis of alveolar macrophages to exacerbate sepsis-induced acute lung injury

Int Immunopharmacol. 2025 Jun 27:162:115140. doi: 10.1016/j.intimp.2025.115140. Online ahead of print.

Authors

Aijun Jia¹, Yueling Wang², Rimei Zhou³, Likun Han³

Affiliations

¹ First Ward of Department of Intensive Care Unit, Guangxi Medical and Health Key Cultivation Discipline, the Affiliated Hospital of Guilin Medical University, NO. 15, Road Lequn, District Xiufeng, Guilin 541001, China. Electronic address: jiaaijunps@163.com.
² Department of Anesthesiology, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha 410008, China.
³ First Ward of Department of Intensive Care Unit, Guangxi Medical and Health Key Cultivation Discipline, the Affiliated Hospital of Guilin Medical University, NO. 15, Road Lequn, District Xiufeng, Guilin 541001, China.

PMID: 40580743
DOI: 10.1016/j.intimp.2025.115140

Abstract

Background: Ubiquitination regulates diverse cellular processes and is implicated in various pathophysiological conditions, including sepsis-induced acute lung injury (ALI). Ubiquitin-specific peptidase 48 (USP48), a deubiquitinating enzyme, has been shown to promote pyroptosis in tumor cells. However, its role in sepsis-induced ALI has not been elucidated. This study aimed to investigate the function and underlying mechanism of USP48 in sepsis-induced ALI.

Methods: A murine model of sepsis-induced ALI was established to assess USP48 expression in lung tissues. In parallel, USP48 levels were examined in lipopolysaccharide (LPS)-stimulated alveolar macrophages. USP48 was then knocked down both in vivo and in vitro to evaluate its functional role. Co-immunoprecipitation (Co-IP) was performed to examine the interaction between USP48 and NEK7. The effects of USP48 on NEK7 ubiquitination and stabilization were assessed in cell-based assays. To further delineate the mechanistic pathway, NEK7 was overexpressed following USP48 knockdown.

Results: USP48 expression was significantly upregulated in the lung tissues of septic mice and in LPS-induced macrophages. In vivo knockdown of USP48 alleviated sepsis-induced ALI and reduced macrophage pyroptosis. In vitro, USP48 enhanced LPS-induced NLRP3 inflammasome activation and macrophage pyroptosis. Co-IP analysis confirmed a direct interaction between USP48 and NEK7. Mechanistically, USP48 promoted NEK7 stabilization by facilitating its deubiquitination. Furthermore, USP48-induced pyroptosis was dependent on NEK7-mediated NLRP3 inflammasome activation. In vivo, USP48 aggravated sepsis-induced ALI through the NEK7/NLRP3/caspase-1/GSDMD signaling axis.

Conclusions: USP48 exacerbates sepsis-induced ALI by promoting pyroptosis of alveolar macrophages through NEK7-mediated activation of the NLRP3 inflammasome, which is facilitated by USP48-induced deubiquitination of NEK7.

Keywords: NEK7; NLRP3; Pyroptosis; Sepsis-induced acute lung injury; USP48.