Building and maintaining the epithelium of the lung

Abstract

Airspaces of the lung are lined by an epithelium whose cellular composition changes along the proximal-to-distal axis to meet local functional needs for mucociliary clearance, hydration, host defense, and gas exchange.Advances in cell isolation, in vitro culture techniques, and genetic manipulation of animal models have increased our understanding of the development and maintenance of the pulmonary epithelium.This review discusses basic cellular mechanisms that regulate establishment of the conducting airway and gas exchange systems as well as the functional maintenance of the epithelium during postnatal life. Proximodistal patterning of the developing lungThe process of lung development in mammals has been best characterized using rodent models.Gastrulation of the developing embryo results in the formation of the three embryonic germ layers whose interactions establish a highly stereotyped body plan.Formation of the anterior foregut pocket results in the establishment of a primitive tube of endoderm surrounded by mesoderm (7).Interactions between these cell types result in the localized formation of primordial buds that give rise to the thymus, lung, liver, and pancreas.The lungs, distal to the trachea, are derived from buds that form from the ventral foregut endoderm at embryonic Conflict of interest: The authors have declared that no conflict of interest exists.