Dynasore Alleviates LPS-Induced Acute Lung Injury by Inhibiting NLRP3 Inflammasome-Mediated Pyroptosis

Abstract

Background

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are clinically severe respiratory disorders without available pharmacological therapies. Dynasore is a cell-permeable molecule that inhibits GTPase activity and exerts protective effects in several disease models. However, whether dynasore can alleviate lipopolysaccharide (LPS)-induced ALI is unknown. This study investigated the effect of dynasore on macrophage activation and explored its potential mechanisms in LPS-induced ALI in vitro and in vivo.

Methods

Bone marrow-derived macrophages (BMDMs) were activated classically with LPS or subjected to NLRP3 inflammasome activation with LPS+ATP. A mouse ALI model was established by the intratracheal instillation (i.t.) of LPS. The expression of PYD domains-containing protein 3 (NLRP3), caspase-1, and gasdermin D (GSDMD) protein was detected by Western blots. Inflammatory mediators were analyzed in the cell supernatant, in serum and bronchoalveolar lavage fluid (BALF) by enzyme-linked immunosorbent assays. Morphological changes in lung tissues were evaluated by hematoxylin and eosin staining. F4/80, Caspase-1 and GSDMD distribution in lung tissue was detected by immunofluorescence.

Results

Dynasore downregulated nuclear factor (NF)-κB signaling and reduced proinflammatory cytokine production in vitro and inhibited the production and release of interleukin (IL)-1β, NLRP3 inflammasome activation, and macrophage pyroptosis through the Drp1/ROS/NLRP3 axis. Dynasore significantly reduced lung injury scores and proinflammatory cytokine levels in both BALF and serum in vivo, including IL-1β and IL-6. Dynasore also downregulated the co-expression of F4/80, caspase-1 and GSDMD in lung tissue.

Conclusion

Collectively, these findings demonstrated that dynasore could alleviate LPS-induced ALI by regulating macrophage pyroptosis, which might provide a new therapeutic strategy for ALI/ARDS.

Keywords:

• acute lung injury
• acute respiratory distress syndrome
• NLRP3 inflammasome
• pyroptosis
• dynasore
• inflammation

Abbreviations

ALI, Acute Lung Injury; ARDS, Acute Respiratory Distress Syndrome; ATP, Adenosine Triphosphate; BALF, Bronchoalveolar Lavage Fluid; BMDMs, Bone Marrow-Derived Macrophages; DAMP, Danger-Associated Molecular Patterns; Drp1, Dynamin-related protein 1; GSDMD, Gasdermin D; H&E, Hematoxylin & Eosin; LPS, Lipopolysaccharide; NLR, NOD-like receptor; ROS, Reactive Oxygen Species.

Disclosure

The authors declare that they have no competing interests in this work.

Additional information

Funding

This work was supported by the Top-level Clinical Discipline Project of Shanghai Pudong (PWYgf2021-05), the National Natural Science Foundation of China (82070076 and 82000082), the National Natural Science Foundation of JiangXi Province (20192ACBL20050), and Provincial Natural Science Foundation of Anhui (2008085QH353).