// Dapeng Yu 1,2,* , Yong Li 2,* , Yu Zhou 3,4,* , Masanobu Abe 5 , Liang Zong 4,6 and Ju Gao 1,2 1 Graduate School of Medicine, The Second Xiangya Hospital of Central South University, Changsha, China 2 Department of Anesthesiology, Clinical Medical School of Yangzhou University (Subei People’s Hospital of Jiangsu Province), Yangzhou, Jiangsu, China 3 Department of General Surgery, Suzhou Municipal Hospital (North Campus), Suzhou, Jiangsu, China 4 Department of Gastrointestinal Surgery, Clinical Medical College of Yangzhou University(the Northern Jiangsu People’s Hospital), Yangzhou, Jiangsu, China 5 Division for Health Service Promotion, University of Tokyo, Tokyo, Japan 6 Department of Gastrointestinal Surgery, Graduate School of Medicine, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, Japan * These authors contributed equally to this work Correspondence to: Liang Zong, email: 250537471@qq.com Ju Gao, email: gaoju_003@163.com Keywords : : rev-erbα; lipopolysaccharide; acute lung injury; nuclear factor-kappa B; toll-like receptor 4 Received: April 04, 2017 Accepted: December 05, 2017 Epub: January 12, 2018 Abstract Background: Nuclear receptor Rev-erbα is a clock gene, which plays an essential regulatory role in metabolic, inflammatory, and cancer-related pathways. In particular, it exhibits a promising role in inflammation-associated diseases, including lipopolysaccharide (LPS)-induced acute lung injury (ALI). In the present study, we aimed to evaluate the effects of REV-erbα on lipopolysaccharide (LPS)-induced ALI in mice via the down-regulation of Toll-like receptor 4 (TLR4) to suppress NF-κB activation. Methods: ALI was induced by an intraperitoneal injection of LPS, using an Rev-erbα-specific agonist, GSK4112, as a positive control. In the bronchoalveolar lavage fluid (BALF), the total protein content, cell counts, as well as the level of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), and polymorphonuclear (MPO) activity was quantified. The lung wet to dry ratio (W/D), histopathologic studies of the lung, and percent survival were also analyzed. The protein expression of NF-κB p65, IκBα, and TLR4 in the lung tissues were assessed. The NF-κB DNA binding activity was assessed via electrophoretic mobility shift assay (EMSA). We also evaluated the activation of NF-κB p65 and TLR4 by confocal microscopy. Results: The Rev-erbα specific agonist, GSK4112, inhibited immune cell recruitment in response to LPS, suppressed acute lung injury, as well as the production of TNF-α, IL-1β, and IL-6 in the BALF of mice. Moreover, GSK4112 significantly inhibited the nuclear translocation and protein expression of TLR4 and NF-κB, resulting in an improved survival rate. Conclusion: Our findings indicate that Rev-erbα plays a protective role in LPS-induced ALI. Therefore, Rev-erbα attenuates the LPS-induced inflammatory response in ALI mice through inhibiting the TLR4 signaling pathway.