Apical Oxidative Hyaluronan Degradation Stimulates Airway Ciliary Beating via RHAMM and RON

• Published in: American journal of respiratory cell and molecular biology Vol. 37; no. 2; pp. 160 - 168
• Main Authors: Manzanares, Dahis, Monzon, Maria-Elena, Savani, Rashmin C, Salathe, Matthias
• Format: Journal Article
• Language: English
• Published: United States Am Thoracic Soc 01.08.2007; American Thoracic Society
• Subjects: Animals; Antibodies - metabolism; Cell Polarity; Cells, Cultured; Cilia - metabolism; Extracellular Matrix Proteins - metabolism; Hepatocyte Growth Factor - genetics; Hepatocyte Growth Factor - metabolism; Humans; Hyaluronan Receptors - metabolism; Hyaluronic Acid - metabolism; Oxidation-Reduction; Proto-Oncogene Proteins - genetics; Proto-Oncogene Proteins - metabolism; Reactive Oxygen Species - metabolism; Receptor Protein-Tyrosine Kinases - metabolism; Respiratory Mucosa - cytology; Respiratory Mucosa - metabolism; Trachea - anatomy & histology; Xanthine - metabolism; Xanthine Oxidase - metabolism
• ISSN: 1044-1549; 1535-4989
• DOI: 10.1165/rcmb.2006-0413OC

Hyaluronan (HA) is synthesized in high-molecular-weight form at the apical pole of airway epithelial cells, covering the luminal surface. When human airway epithelial cells grown and redifferentiated at the air-liquid interface (ALI) were exposed to xanthine/xanthine oxidase (X/XO), ciliary beat frequency (CBF) increased. This effect was blocked by superoxide dismutase (SOD) and catalase. Inhibition of hyaluronan synthesis inhibited the CBF response to X/XO, while addition of exogenous HA amplified it. A functionally blocking antibody to the receptor for hyaluronic acid-mediated motility (RHAMM) reduced the CBF response to X/XO. Since RHAMM has no transmembrane domain and thus cannot signal on its own, the association of RHAMM with recepteur d'origine nantais (RON), a member of the hepatocyte growth factor receptor family, was explored. Immunohistochemistry of human airway epithelium showed co-localization of RHAMM and RON at the apex of ciliated cells. Physical association of RHAMM and RON was confirmed with co-immunoprecipitations. Macrophage-stimulating protein (MSP), an agonist of RON, stimulated CBF. Genistein, a nonspecific tyrosine kinase inhibitor, and MSP beta chain (beta-MSP), a specific RON inhibitor, blocked the X/XO-induced CBF increase. HA present in the apical secretions of human airway epithelial cells was shown to degrade upon exposure to X/XO, a process inhibited by SOD. Low-molecular-weight HA fragments stimulated CBF, an effect blocked by anti-RHAMM antibody and genistein. These data suggest that high molecular form HA is broken down by reactive oxygen species to form low-molecular-weight fragments that signal via RHAMM and RON to stimulate CBF.