Role of galectin-3 in human pulmonary fibrosis

Allergol Int. 2007 Mar;56(1):57-65. doi: 10.2332/allergolint.O-06-449. Epub 2007 Jan 29.


Background: Galectin-3 is a beta-galactoside-binding protein which is implicated in diverse physiological and pathological processes including human liver cirrhosis and a mouse lung fibrosis model. The aim of this study is to determine whether galectin-3 is involved in human lung fibrosis.

Methods: We measured galectin-3 concentration in bronchoalveolar lavage fluid (BALF) and examined its expression in alveolar macrophages from patients with interstitial lung disorders using ELISA and immunohistochemical staining, respectively. Using monocyte/macrophage cell lines in vitro, we examined the effect of cytokines on galectin-3 expression, and the opposite similarly by RT-PCR and Western blotting. Finally, we performed Micro Boyden chamber assay and Sircoll assay to determine whether galectin-3 induces migration and collagen synthesis, respectively, in fibroblasts.

Results: Galectin-3 was specifically increased in BALF from patients with idiopathic pulmonary fibrosis (IPF) and interstitial pneumonia associated with collagen vascular disease (CVD-IP). Galectin-3 levels in BALF seemed to be lower in IPF and CVD-IP patients receiving corticosteroid therapy. Alveolar macrophages from IPF patients expressed more galectin-3 compared with those from control. Galectin-3 expression was induced by tumor necrosis factor-alpha (TNF-alpha) and interferon (IFN)-gamma in a monocytic cell line U937. Galectin-3 also induced mRNA expression and protein production of TNF-alpha and interleukin (IL)-8 in a macrophage cell line THP-1. This lectin stimulated NIH-3T3 fibroblast to induce migration and collagen synthesis in vitro.

Conclusions: These results suggest that galectin-3 is involved in the pathogenesis of human IPF and CVD-IP by activating macrophages and fibroblasts.

MeSH terms

  • Adrenal Cortex Hormones / therapeutic use
  • Blotting, Western
  • Bronchoalveolar Lavage Fluid / chemistry
  • Bronchoalveolar Lavage Fluid / cytology
  • Cell Movement / physiology
  • Collagen / biosynthesis
  • Enzyme-Linked Immunosorbent Assay
  • Fibroblasts / immunology
  • Fibroblasts / metabolism*
  • Fluorescent Antibody Technique
  • Galectin 3 / metabolism*
  • Humans
  • Immunohistochemistry
  • Lung Diseases, Interstitial / drug therapy
  • Lung Diseases, Interstitial / metabolism
  • Macrophage Activation / physiology
  • Macrophages, Alveolar / immunology
  • Macrophages, Alveolar / metabolism*
  • Pulmonary Fibrosis / immunology
  • Pulmonary Fibrosis / metabolism*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Vascular Diseases / drug therapy
  • Vascular Diseases / metabolism


  • Adrenal Cortex Hormones
  • Galectin 3
  • Collagen