EPITHELIAL-MESENCHYMAL INTERACTIONS IN THE ALTERATION OF GENE-EXPRESSION AND MORPHOLOGY FOLLOWING LUNG INJURY

Numerous studies using morphologic techniques have demonstrated the pl asticity of pulmonary epithelial cells and the requirement for complex intercellular interactions for regeneration of normal epithelium foll owing lung injury. Recent developments in the molecular characterizati on of genes expressed in the lung have generated additional tools for evaluation of lung cell phenotypes and interactions. This review discu sses the relationship between molecular and morphologic changes in lun g cells during injury and repair. Changes in epithelial morphology and their differentiated gene products may be mediated through alteration s in expression of numerous factors acting through paracrine and autoc rine mechanisms. Tumor necrosis factor alpha, transforming growth fact or beta, and retinoic acid, whose roles in the regulation of epithelia l cell differentiation have been well documented, will be discussed in the context of normal lung development and repair from injury. (C) 19 97 Wiley-Liss, Inc.