REGULATION OF TRANSFERRIN GENE-EXPRESSION DURING LUNG DEVELOPMENT ANDINJURY

Regulation of transferrin gene expression during lung development and injury. Am. J. Physiol. 273 (Lung Cell. Mol. Physiol. 17): L417-L426, 1997.-Transferrin (TF), the major iron-transporting protein in vertebr ates, is mainly synthesized in the liver. Although its source in lung is unknown, TF is a major inhibitor for lipid peroxidation and microbi al propagation in lung fluid, and iron-free TF has been shown in rabbi ts to decrease the severity of respiratory failure and to improve surf actant activity. This study shows that TF is produced and secreted by the lung. In baboons and humans, TF gene expression displays distinct temporal patterns in different lung cells as revealed by in situ hybri dization. Although expression of TF mRNA in submucosal glands remains active during development and throughout adulthood, its level in airwa y epithelia increases with advancing gestational age, reaches its peak before birth, declines 6-12 mo after birth, and diminishes in the old er adult. in premature baboons maintained on ventilatory support, expr ession of TF mRNA is suppressed in both airway epithelium and glands. TF production by airway epithelia before birth most likely prevents ox idative damage in the newborn period, and its loss during injury may a llow further lung damage.