Carbon Monoxide Releasing Molecule-2-Upregulated ROS-Dependent Heme Oxygenase-1 Axis Suppresses Lipopolysaccharide-Induced Airway Inflammation

• Published in: International journal of molecular sciences Vol. 20; no. 13; p. 3157
• Main Authors: Lin, Chih-Chung, Hsiao, Li-Der, Cho, Rou-Ling, Yang, Chuen-Mao
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 28.06.2019; MDPI
• Subjects: Animals; Anti-Inflammatory Agents - pharmacology; Carbon monoxide; Cells, Cultured; Cyclic AMP-Dependent Protein Kinases - metabolism; Cytokines; Focal Adhesion Kinase 2 - metabolism; Gene expression; Growth factors; Heme Oxygenase-1 - genetics; Heme Oxygenase-1 - metabolism; Homeostasis; Humans; Inflammation; Intercellular Adhesion Molecule-1 - metabolism; Kinases; Lipopolysaccharides - toxicity; Male; MAP Kinase Signaling System; Mice; Mice, Inbred ICR; Myocytes, Smooth Muscle - drug effects; Myocytes, Smooth Muscle - metabolism; NADPH Oxidases - metabolism; Organometallic Compounds - pharmacology; Oxidative stress; Phosphorylation; Physiology; Protein expression; Proteins; Reactive Oxygen Species - metabolism; Smooth muscle; Trachea - cytology; Trachea - metabolism; Tracheitis - etiology; Tracheitis - metabolism; Tumor necrosis factor-TNF; CORM-2; HO-1; AP-1; NADPH oxidase; ROS
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms20133157

The up-regulation of heme oxygenase-1 (HO-1) is mediated through nicotinamaide adenine dinucleotide phosphate (NADPH) oxidases (Nox) and reactive oxygen species (ROS) generation, which could provide cytoprotection against inflammation. However, the molecular mechanisms of carbon monoxide-releasing molecule (CORM)-2-induced HO-1 expression in human tracheal smooth muscle cells (HTSMCs) remain unknown. Here, we found that pretreatment with CORM-2 attenuated the lipopolysaccharide (LPS)-induced intercellular adhesion molecule (ICAM-1) expression and leukocyte count through the up-regulation of HO-1 in mice, which was revealed by immunohistochemistrical staining, Western blot, real-time PCR, and cell count. The inhibitory effects of HO-1 by CORM-2 were reversed by transfection with HO-1 siRNA. Next, Western blot, real-time PCR, and promoter activity assay were performed to examine the HO-1 induction in HTSMCs. We found that CORM-2 induced HO-1 expression via the activation of protein kinase C (PKC)α and proline-rich tyrosine kinase (Pyk2), which was mediated through Nox-derived ROS generation using pharmacological inhibitors or small interfering ribonucleic acids (siRNAs). CORM-2-induced HO-1 expression was mediated through Nox-(1, 2, 4) or p47phox, which was confirmed by transfection with their own siRNAs. The Nox-derived ROS signals promoted the activities of extracellular signal-regulated kinase 1/2 (ERK1/2). Subsequently, c-Fos and c-Jun—activator protein-1 (AP-1) subunits—were up-regulated by activated ERK1/2, which turned on transcription of the HO-1 gene by regulating the HO-1 promoter. These results suggested that in HTSMCs, CORM-2 activates PKCα/Pyk2-dependent Nox/ROS/ERK1/2/AP-1, leading to HO-1 up-regulation, which suppresses the lipopolysaccharide (LPS)-induced airway inflammation.