Transcriptional Characterization of Bronchoalveolar Lavage Fluid Reveals Immune Microenvironment Alterations in Chemically Induced Acute Lung Injury

Chao Cao; Obulkasim Memet; Fuli Liu; Hanbing Hu; Lin Zhang; Heng Jin; Yiqun Cao; Jian Zhou; Jie Shen

doi:10.2147/JIR.S407580

Transcriptional Characterization of Bronchoalveolar Lavage Fluid Reveals Immune Microenvironment Alterations in Chemically Induced Acute Lung Injury

J Inflamm Res. 2023 May 17:16:2129-2147. doi: 10.2147/JIR.S407580. eCollection 2023.

Authors

Chao Cao^{1

2

3

4}, Obulkasim Memet^{1

2

3}, Fuli Liu^{1

2}, Hanbing Hu^{1

2

3}, Lin Zhang^{1

2}, Heng Jin⁴, Yiqun Cao⁴, Jian Zhou^{3

5

6}, Jie Shen^{1

2

3}

Affiliations

¹ Center of Emergency and Critical Medicine, Jinshan Hospital of Fudan University, Shanghai, People's Republic of China.
² Research Center for Chemical Injury, Emergency and Critical Medicine of Fudan University, Shanghai, People's Republic of China.
³ Shanghai Medical College, Fudan University, Shanghai, People's Republic of China.
⁴ Emergency Department, Tianjin Medical University General Hospital, Tianjin, People's Republic of China.
⁵ Department of Pulmonary and Critical Care Medicine, Shanghai Respiratory Research Institute, Zhongshan Hospital of Fudan University, Shanghai, People's Republic of China.
⁶ Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai, People's Republic of China.

Abstract

Purpose: Chemically induced acute lung injury (CALI) has become a serious health concern in our industrialized world, and abnormal functional alterations of immune cells crucially contribute to severe clinical symptoms. However, the cell heterogeneity and functional phenotypes of respiratory immune characteristics related to CALI remain unclear.

Methods: We performed scRNA sequencing on bronchoalveolar lavage fluid (BALF) samples obtained from phosgene-induced CALI rat models and healthy controls. Transcriptional data and TotalSeq technology were used to confirm cell surface markers identifying immune cells in BALF. The landscape of immune cells could elucidate the metabolic remodeling mechanism involved in the progression of acute respiratory distress syndrome and cytokine storms. We used pseudotime inference to build macrophage trajectories and the corresponding model gene expression changes, and identified and characterized alveolar cells and immune subsets that may contribute to CALI pathophysiology based on gene expression profiles at single-cell resolution.

Results: The immune environment of cells, including dendritic cells and specific macrophage subclusters, exhibited increased function during the early stage of pulmonary tissue damage. Nine different subpopulations were identified that perform multiple functional roles, including immune responses, pulmonary tissue repair, cellular metabolic cycle, and cholesterol metabolism. Additionally, we found that individual macrophage subpopulations dominate the cell-cell communication landscape. Moreover, pseudo-time trajectory analysis suggested that proliferating macrophage clusters exerted multiple functional roles.

Conclusion: Our findings demonstrate that the bronchoalveolar immune microenvironment is a fundamental aspect of the immune response dynamics involved in the pathogenesis and recovery of CALI.

Keywords: chemically induced acute lung injury; heterogeneity; immune microenvironment; phenotypes; phosgene-inhalation; single cell RNAseq.

Grants and funding

This work was supported by grants from the National Natural Science Foundation of China (No. 81902007 to CC, 82072222 to HJ, 82272243 to JS), the Natural Science Foundation of Tianjin (No. 19JCQNJC10000 to CC), the Binhai New District Health Commission Science Foundation of Tianjin (No. 2019BWKY012 to CC), the Shanghai Municipal Science and Technology Major Project (No. ZD2021CY001 to JZ), and the Science and Technology Committee of Jinshan District, Shanghai (No. 2019-3-07 to JS).