Dysregulation of galectin-3. Implications for Hermansky-Pudlak syndrome pulmonary fibrosis

• Published in: American journal of respiratory cell and molecular biology Vol. 50; no. 3; pp. 605 - 613
• Main Authors: Cullinane, Andrew R, Yeager, Caroline, Dorward, Heidi, Carmona-Rivera, Carmelo, Wu, Hai Ping, Moss, Joel, O'Brien, Kevin J, Nathan, Steven D, Meyer, Keith C, Rosas, Ivan O, Helip-Wooley, Amanda, Huizing, Marjan, Gahl, William A, Gochuico, Bernadette R
• Format: Journal Article
• Language: English
• Published: United States American Thoracic Society 01.03.2014
• Subjects: Alveolar Epithelial Cells - metabolism; Biosynthesis; Bronchoalveolar Lavage Fluid - chemistry; Case-Control Studies; Cell adhesion & migration; Cells, Cultured; Fibroblasts - metabolism; Galectin 3 - genetics; Galectin 3 - metabolism; Gene Expression Regulation; Hermanski-Pudlak Syndrome - complications; Hermanski-Pudlak Syndrome - genetics; Hermanski-Pudlak Syndrome - metabolism; Humans; Idiopathic Pulmonary Fibrosis - metabolism; Lung - metabolism; Lung - pathology; Lung diseases; Membrane Proteins - genetics; Membrane Proteins - metabolism; Mortality; Mucin-1 - metabolism; Mutation; Original Research; Pathogenesis; Protein Transport; Proteins; Pulmonary fibrosis; Pulmonary Fibrosis - diagnosis; Pulmonary Fibrosis - etiology; Pulmonary Fibrosis - genetics; Pulmonary Fibrosis - metabolism; RNA, Messenger - metabolism; Severity of Illness Index; Studies; Surfactants; Transfection
• ISSN: 1044-1549; 1535-4989
• DOI: 10.1165/rcmb.2013-0025oc

The etiology of Hermansky-Pudlak syndrome (HPS) pulmonary fibrosis (HPSPF), a progressive interstitial lung disease with high mortality, is unknown. Galectin-3 is a β-galactoside-binding lectin with profibrotic effects. The objective of this study was to investigate the involvement of galectin-3 in HPSPF. Galectin-3 was measured by ELISA, immunohistochemistry, and immunoblotting in human specimens from subjects with HPS and control subjects. Mechanisms of galectin-3 accumulation were studied by quantitative RT-PCR, Northern blot analysis, membrane biotinylation assays, and rescue of HPS1-deficient cells by transfection. Bronchoalveolar lavage galectin-3 concentrations were significantly higher in HPSPF compared with idiopathic pulmonary fibrosis or that from normal volunteers, and correlated with disease severity. Galectin-3 immunostaining was increased in HPSPF compared with idiopathic pulmonary fibrosis or normal lung tissue. Fibroblasts from subjects with HPS subtypes associated with pulmonary fibrosis had increased galectin-3 protein expression compared with cells from nonfibrotic HPS subtypes. Galectin-3 protein accumulation was associated with reduced Galectin-3 mRNA, normal Mucin 1 levels, and up-regulated microRNA-322 in HPSPF cells. Membrane biotinylation assays showed reduced galectin-3 and normal Mucin 1 expression at the plasma membrane in HPSPF cells compared with control cells, which suggests that galectin-3 is mistrafficked in these cells. Reconstitution of HPS1 cDNA into HPS1-deficient cells normalized galectin-3 protein and mRNA levels, as well as corrected galectin-3 trafficking to the membrane. Intracellular galectin-3 levels are regulated by HPS1 protein. Abnormal accumulation of galectin-3 may contribute to the pathogenesis of HPSPF.