Mesenchymal stem cells alleviate LPS-induced acute lung injury by inhibiting the proinflammatory function of Ly6C+ CD8+ T cells

Jiaqi Zhu,Lanjuan Li,Xiaowei Shi,Hongcui Cao,Yanping Xu,Wenyi Chen,Xinyu Sheng,Jingqi Liu,Xudong Feng,Jiong Yu,Bing Feng,Qiaoling Pan

doi:10.1038/s41419-020-03036-1

Abstract

Systemic inflammatory processes, including alveolar injury, cytokine induction, and neutrophil accumulation, play key roles in the pathophysiology of acute lung injury (ALI). The immunomodulatory effects of mesenchymal stem cells (MSCs) can contribute to the treatment of inflammatory disorders. In previous studies, the focus was on innate immune cells and the effects of MSCs on ALI through CD8+ T cells remain unclear. In the present study, lipopolysaccharide (LPS) was used to induce ALI in mice. ALI mice were treated with MSCs via intratracheal instillation. Survival rate, histopathological changes, protein levels, total cell count, cytokine levels, and chemokine levels in alveolar lavage fluid were used to determine the efficacy of MSCs. Mass cytometry and single-cell RNA sequencing (scRNA-seq) were used to characterize the CD8+ T cells in the lungs. Ly6C− CD8+ T cells are prevalent in normal mice, whereas a specialized effector phenotype expressing a high level of Ly6C is predominant in advanced disease. MSCs significantly mitigated ALI and improved survival. MSCs decreased the infiltration of CD8+ T cells, especially Ly6C+ CD8+ T cells into the lungs. Mass cytometry revealed that CD8+ T cells expressing high Ly6C and CXCR3 levels caused tissue damage in the lungs of ALI mice, which was alleviated by MSCs. The scRNA-seq showed that Ly6C+ CD8+ T cells exhibited a more activated phenotype and decreased expression of proinflammatory factors that were enriched the most in immune chemotaxis after treatment with MSCs. We showed that CD8+ T cells play an important role in MSC-mediated ALI remission, and both infiltration quantity and proinflammatory function were inhibited by MSCs, indicating a potential mechanism for therapeutic intervention.

Highlights

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are a continuum of lung changes caused by multiple lung injuries, often resulting in severe morbidity and death[1,2]
To determine how Mesenchymal stem cells (MSCs) ameliorate LPS-induced ALI, mice were divided into three groups: phosphate-buffered saline (PBS)/PBS, LPS/PBS, and LPS/MSC (Fig. 1a)
The bronchoalveolar lavage fluid (BALF) protein level peaked at day 3 and gradually decreased at day 7 after PBS or MSC treatment

Summary

Introduction

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are a continuum of lung changes caused by multiple lung injuries, often resulting in severe morbidity and death[1,2] These diseases lead to respiratory failure, increase susceptibility to multiple organ dysfunction, and are a common cause of death in critically ill Official journal of the Cell Death Differentiation Association. Zhu et al Cell Death and Disease (2020)11:829 preclinical studies support the transplantation of MSCs for treatment of ALI11,12. MSCs were shown to reduce CD8+ cytotoxic T cells via stanniocalcin-2 and to alleviate the inflammatory reaction in mice[15]. Whether MSC transplantation reduced the risk of death in ALI mice by affecting Ly6C+ CD8+ T cells was investigated

Methods

Results

Conclusion