Lysophosphatidic acid (LPA), a bioactive phospholipid, induces a wide range of cellular effects, including gene expression, cytoskeletal rearrangement, and cell survival. We have previously shown that LPA stimulates secretion of pro-and antiinflammatory cytokines in bronchial epithelial cells. This study provides evidence that LPA enhances pulmonary epithelial barrier integrity through protein kinase C (PKC) ␦-and -mediated