Lipid Deficiency Contributes to Impaired Alveolar Progenitor Cell Function in Aging and Idiopathic Pulmonary Fibrosis

Am J Respir Cell Mol Biol. 2024 Apr 24. doi: 10.1165/rcmb.2023-0290OC. Online ahead of print.ABSTRACTIdiopathic pulmonary fibrosis (IPF) is an aging-associated interstitial lung disease resulting from repeated epithelial injury and inadequate epithelial repair. Alveolar type II cells (AEC2) are progenitor cells that maintain epithelial homeostasis and repair the lung after injury. In the current study, we assessed lipid metabolism in AEC2s from human lungs of IPF patients and healthy donors, as well as AEC2s from bleomycin-injured young and old mice. Through single cell RNA sequencing (scRNA-seq), we observed that lipid metabolism-related genes were downregulated in IPF AEC2s and bleomycin-injured mouse AEC2s. Aging aggravated this decrease and hindered recovery of lipid metabolism gene expression in AEC2s after bleomycin injury. Pathway analyses revealed down-regulation of genes related to lipid biosynthesis and fatty acid -oxidation in AEC2s from IPF lungs and bleomycin-injured, aged mouse lungs compared to the respective controls. We confirmed decreased cellular lipid content in AEC2s from IPF lungs and bleomycin-injured, aged mouse lungs using immunofluorescence staining and flow cytometry. We further show that lipid metabolism was associated with AEC2 progenitor function. Lipid supplementation and peroxisome proliferator activated receptor gamma (PPARγ) activation promoted progenitor renewal capacity of both human and mouse AEC2s in 3D organoid cultures. Lipid supple...
Source: Am J Respir Cell Mol... - Category: Respiratory Medicine Authors: Source Type: research