Apical oxidative hyaluronan degradation stimulates airway ciliary beating via RHAMM and RON.
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.
Manzanares
Dahis
D
Division of Pulmonary and Critical Care Medicine, University of Miami Miller School of Medicine, 1600 NW 10th Ave., RMSB 7063A (R-47), Miami, FL 33136, USA.
Monzon
Maria-Elena
ME
Savani
Rashmin C
RC
Salathe
Matthias
M
D000818:Animals; D000906:Antibodies / Q000378:metabolism; D016764:Cell Polarity; D002478:Cells, Cultured; D002923:Cilia / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D017228:Hepatocyte Growth Factor / Q000235:genetics / Q000378:metabolism; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism*; D006820:Hyaluronic Acid / Q000378:metabolism*; D010084:Oxidation-Reduction; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism*; D020545:Respiratory Mucosa / Q000166:cytology* / Q000378:metabolism; D014132:Trachea / Q000033:anatomy & histology; D019820:Xanthine / Q000378:metabolism; D014969:Xanthine Oxidase / Q000378:metabolism
D000906:Antibodies; D016326:Extracellular Matrix Proteins; D018960:Hyaluronan Receptors; D011518:Proto-Oncogene Proteins; D017382:Reactive Oxygen Species; C098946:hyaluronan-mediated motility receptor; C082332:macrophage stimulating protein; D019820:Xanthine; D017228:Hepatocyte Growth Factor; D006820:Hyaluronic Acid; D014969:Xanthine Oxidase; C080835:RON protein; D020794:Receptor Protein-Tyrosine Kinases