Angiocrine Sphingosine-1-Phosphate Activation of S1PR2-YAP Signaling Axis in Alveolar Type II Cells Is Essential for Lung Repair
Qian Chen,
Jalees Rehman,
Manwai Chan,
Panfeng Fu,
Steven M. Dudek,
Viswanathan Natarajan,
Asrar B. Malik,
Yuru Liu
Affiliations
Qian Chen
Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL 60612, USA
Jalees Rehman
Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL 60612, USA
Manwai Chan
Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
Panfeng Fu
Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL 60612, USA
Steven M. Dudek
Division of Pulmonary, Critical Care, Sleep and Allergy, Department of Medicine, University of Illinois College of Medicine, Chicago, IL 60612, USA
Viswanathan Natarajan
Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL 60612, USA; Division of Pulmonary, Critical Care, Sleep and Allergy, Department of Medicine, University of Illinois College of Medicine, Chicago, IL 60612, USA
Asrar B. Malik
Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL 60612, USA
Yuru Liu
Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL 60612, USA; Corresponding author
Summary: Lung alveolar epithelium is composed of alveolar type I (AT1) and type II (AT2) cells. AT1 cells mediate gas exchange, whereas AT2 cells act as progenitor cells to repair injured alveoli. Lung microvascular endothelial cells (LMVECs) play a crucial but still poorly understood role in regulating alveolar repair. Here, we studied the role of the LMVEC-derived bioactive lipid sphingosine-1-phosphate (S1P) in promoting alveolar repair using mice with endothelial-specific deletion of sphingosine kinase 1 (Sphk1), the key enzyme promoting S1P generation. These mutant lungs developed airspace-enlargement lesions and exhibited a reduced number of AT1 cells after Pseudomonas-aeruginosa-induced lung injury. We demonstrated that S1P released by LMVECs acted via its receptor, S1PR2, on AT2 cells and induced nuclear translocation of yes-associated protein (YAP), a regulator of AT2 to AT1 transition. Thus, angiocrine S1P released after injury acts via the S1PR2-YAP signaling axis on AT2 cells to promote AT2 to AT1 differentiation required for alveolar repair.
