Adipose-Derived Mesenchymal Stem Cells Ameliorating Pseudomonas aeruginosa-induced Acute Lung Infection via Inhibition of NLRC4 Inflammasome

Lu-Lu Li; Ying-Gang Zhu; Xin-Ming Jia; Dong Liu; Jie-Ming Qu

doi:10.3389/fcimb.2020.581535

Adipose-Derived Mesenchymal Stem Cells Ameliorating Pseudomonas aeruginosa-induced Acute Lung Infection via Inhibition of NLRC4 Inflammasome

Front Cell Infect Microbiol. 2021 Jan 8:10:581535. doi: 10.3389/fcimb.2020.581535. eCollection 2020.

Authors

Lu-Lu Li^{1

2}, Ying-Gang Zhu³, Xin-Ming Jia⁴, Dong Liu^{1

2}, Jie-Ming Qu^{1

2}

Affiliations

¹ Department of Respiratory and Critical Care Medicine, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
² Institute of Respiratory Diseases, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
³ Department of Respiratory and Critical Care Medicine, Huadong Hospital, Fudan University, Shanghai, China.
⁴ Clinical Translational Research Center, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China.

Abstract

Background: Pseudomonas aeruginosa (PA) is one of the most common Gram-negative bacteria causing hospital-acquired pulmonary infection, with high drug resistance and mortality. Therefore, it is urgent to introduce new non-antibiotic treatment strategies. Mesenchymal stem cells (MSCs), as important members of the stem cell family, were demonstrated to alleviate pathological damage in acute lung injury. However, the potential mechanism how MSC alleviate acute lung infection caused by PA remains unclear.

Objective: The purpose of this study was to investigate the effects of Adipose-derived mesenchymal stem cells (ASCs) on acute pulmonary infections and the possible mechanisms how ASCs reduce pulmonary inflammation induced by PA.

Methods: The therapeutic and mechanistic effects of ASCs on PA pulmonary infection were evaluated respectively in a murine model as well as in an in vitro model stimulated by PA and co-cultured with ASCs.

Results: 1. ASCs treatment significantly reduced the bacterial load, inflammation of lung tissue and histopathological damage by PA. 2. PA infection mainly activated Nod-like receptor containing a caspase activating and recruitment domain 4 (NLRC4) inflammasome in the lung of mice. ASCs attenuated acute lung infection in mice by inhibiting NLRC4 inflammasome activation. 3. NLRC4^-/- mice showed a significant improvement in survival rate and lung bacterial load after PA infection. 4. ASCs mainly increased expression and secretion of STC-1 in response to PA-stimulated NLRC4 inflammasome activation.

Conclusions: PA infection attenuated macrophage phagocytosis through activation of NLRC4 inflammasome in macrophages, which eventually led to pulmonary inflammatory damage in mouse; ASCs reduced the activation of NLRC4 inflammasome in macrophages induced by PA infection, thereby increasing the phagocytic ability of macrophages, and ultimately improving lung tissue damage in mouse; ASCs may inhibit NLRC4 inflammasome through the secretion of STC-1.

Keywords: NLRC4; Pseudomonas aeruginosa; acute pulmonary infection; inflammasome; mesenchymal stem cells.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Apoptosis Regulatory Proteins / metabolism
Calcium-Binding Proteins
Inflammasomes* / metabolism
Lung / metabolism
Mesenchymal Stem Cells* / metabolism
Mice
Mice, Inbred C57BL
Pseudomonas aeruginosa / metabolism

Substances

Apoptosis Regulatory Proteins
Calcium-Binding Proteins
Inflammasomes