Trajectory modeling of endothelial-to-mesenchymal transition reveals galectin-3 as a mediator in pulmonary fibrosis

Wangyue Jia,Jian Wu,Ceshu Gao,Qiong Wu,Zhaoyan Wang

doi:10.1038/s41419-021-03603-0

Abstract

The endothelial-to-mesenchymal transition (EndMT) is an important source of fibrotic cells in idiopathic pulmonary fibrosis (IPF). However, how endothelial cells (ECs) are activated and how EndMT impact IPF remain largely elusive. Here, we use unsupervised pseudotemporal analysis to recognize the heterogeneity of ECs and reconstruct EndMT trajectory of bleomycin (BLM)-treated Tie2creER/+;Rosa26tdTomato/+ IPF mice. Genes like C3ar1 and Lgals3 (protein name galectin-3) are highly correlated with the transitional pseudotime, whose expression is gradually upregulated during the fate switch of ECs from quiescence to activation in fibrosis. Inhibition of galectin-3 via siRNA or protein antagonists in mice could alleviate the pathogenesis of IPF and the transition of ECs. With the stimulation of human pulmonary microvascular endothelial cells (HPMECs) by recombinant proteins and/or siRNAs for galectin-3 in vitro, β-catenin/GSK3β signaling and its upstream regulator AKT are perturbed, which indicates they mediate the EndMT progress. These results suggest that EndMT is essential to IPF process and provide potential therapeutic targets for vascular remodeling.

Highlights

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive lung disease with few clinical treatment options[1]
Resident endothelial cells (ECs) decreased in BLM-induced pulmonary fibrosis In order to investigate the prevalence of endothelial-to-mesenchymal transition (EndMT) in pulmonary fibrosis, the pulmonary fibrosis model was established by intratracheal administration of BLM firstly
We used immunofluorescence staining to find that CD31-positive ECs scattered throughout the fibrotic area in the BLMtreated pulmonary fibrotic samples (BLM groups), while in the control groups CD31 expression could only be detected in pulmonary microvascular and arterial blood vessels

Summary

Introduction

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive lung disease with few clinical treatment options[1]. It is characterized by the deposition of extracellular matrix (ECM) material in fibroblast foci, which may lead to the loss of lung compliance and disruption of gas exchange[2]. Recent evidence suggests that the origin of lung fibroblasts plays a central role in the development of pulmonary fibrosis[3,4], which provides potential therapeutic targets and novel ideas for treatment strategies. The transformation of ECs into the mesenchymal phenotype is not a simple binary event, which imposes great challenges for the pharmaceutical treatment of EndMT-related diseases. Recent studies attempted to define cell transformation during EndMT using singlecell RNA sequencing (scRNA-seq) approaches[12,13], highlighting scRNA-seq as an important strategy for Official journal of the Cell Death Differentiation Association

Methods

Results

Conclusion