Macrophages programmed by apoptotic cells inhibit epithelial-mesenchymal transition in lung alveolar epithelial cells via PGE2, PGD2, and HGF

Young So Yoon, Ye Ji Lee, Youn Hee Choi, Young Mi Park, Jihee Lee Kang

Research output: Contribution to journalArticlepeer-review

32 Scopus citations

Abstract

Apoptotic cell clearance results in the release of growth factors and the action of signaling molecules involved in tissue homeostasis maintenance. Here, we investigated whether and how macrophages programmed by apoptotic cells inhibit the TGF-β1-induced Epithelial-mesenchymal transition (EMT) process in lung alveolar epithelial cells. Treatment with conditioned medium derived from macrophages exposed to apoptotic cells, but not viable or necrotic cells, inhibited TGF-β1-induced EMT, including loss of E-cadherin, synthesis of N-cadherin and α-smooth muscle actin, and induction of EMT-activating transcription factors, such as Snail1/2, Zeb1/2, and Twist1. Exposure of macrophages to cyclooxygenase (COX-2) inhibitors (NS-398 and COX-2 siRNA) or RhoA/Rho kinase inhibitors (Y-27632 and RhoA siRNA) and LA-4 cells to antagonists of prostaglandin E2(PGE2) receptor (EP4 [AH-23848]), PGD2 receptors (DP1 [BW-A868C] and DP2 [BAY-u3405]), or the hepatocyte growth factor (HGF) receptor c-Met (PHA-665752), reversed EMT inhibition by the conditioned medium. Additionally, we found that apoptotic cell instillation inhibited bleomycin-mediated EMT in primary mouse alveolar type II epithelial cells in vivo. Our data suggest a new model for epithelial cell homeostasis, by which the anti-EMT programming of macrophages by apoptotic cells may control the progressive fibrotic reaction via the production of potent paracrine EMT inhibitors.

Original languageEnglish
Article number20992
JournalScientific Reports
Volume6
DOIs
StatePublished - 15 Feb 2016

Bibliographical note

Funding Information:
This work was supported by a grant from the Korea Healthcare Technology R&D Project, Ministry for Health, Welfare & Family Affairs, Republic of Korea (A121065) and by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (2010-0027945).

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