The nuclear receptor and clock gene REV-ERBα regulates cigarette smoke-induced lung inflammation

REV-ERB alpha is a nuclear heme receptor, transcriptional repressor and critical component of the molecular clock that drives daily rhythms of metabolism. Evidence reveals that REV-ERB alpha also plays an important regulatory role in clock-dependent lung physiology and inflammatory responses. We hypothesize that cigarette smoke (CS) exposure influences REV-ERB alpha abundance in the lungs, facilitating a pro inflammatory phenotype. To determine the impact of REV-ERB alpha activation in the CS-induced inflammatory response we treated primary human small airway epithelial cells (SAECs) with CS extract (CSE) or lipopolysaccharide (LPS) in the absence or presence of pre-treatment with the REV-ERB alpha agonist GSK 4112. We also exposed adult C57BL/6J (WT) and Rev-erb alpha global KO mice to CS (10 and 30 days) and measured pro-inflammatory cytokine release. Our data reveal that pre-treatment with GSK 4112 reduced CSE/LPS induced pro-inflammatory cytokines release from both SAECs and mouse lung fibroblasts (MLFs). Furthermore, REV-ERB alpha KO mice show a greater inflammatory response to 10 and 30 days of CS, including increased neutrophil lung influx, pro-inflammatory cytokine (IL-6, MCP-1 and KC) release, and pro-senescence marker (p16) when compared to WT mice. These data demonstrate that REV-ERB alpha is a critical regulator of CS-induced lung inflammatory responses. (C) 2017 Elsevier Inc. All rights reserved.