Gene Expression Studies in Lung Development and Lung Stem Cell Biology

Role of PPARs and Retinoid X Receptors in the Regulation of Lung Maturation and Development

Understanding lung development has significant importance to public health because of the fact that interruptions in the normal developmental processes can have prominent effects on childhood and adult lung health. It is widely appreciated that the retinoic acid (RA) pathway plays an important role in lung development. Additionally, PPARs are believed to partner with receptors of this pathway and therefore could be considered extensions of retinoic acid function, including during lung development. This review will begin by introducing the relationship between the retinoic acid pathway and PPARs followed by an overview of lung development stages and regulation to conclude with details on PPARs and the retinoic acid pathway as they may relate to lung development.

Galectin-1 in secondary alveolar septae of neonatal mouse lung

In mice, alveolarization occurs during postnatal days 4 through 12, when secondary alveolar septae create thin-walled alveoli in the distal lung. We hypothesized that genes predominantly expressed in newly forming secondary alveolar septae influence the process of alveolarization. To address this hypothesis, tips of secondary alveolar septae were isolated from sections of postnatal day 6 mouse lung tissue using laser capture microdissection. Total RNA was isolated and amplified from the dissected alveolar septal tips and from intact postnatal day 6 lung tissue. Gene expression in the samples was characterized using Affymetrix mouse U74AN2 GeneChips. Galectin-1 was an abundantly expressed transcript that was enriched in the alveolar septal tips compared with levels in the whole lung tissue. Galectins are β-galactoside-binding proteins involved in the regulation of cell proliferation, differentiation, and apoptosis in fibroblasts, muscle cells and endothelial cells, cell types that are present in the alveolar wall. Immunostaining in postnatal day 6 lung tissue confirmed that galectin-1 protein is concentrated in the tips of secondary alveolar septae, predominantly in myofibroblasts. Fibroblasts isolated from day 6 neonatal mouse lung tissue contained galectin-1 protein. Real-time PCR demonstrated that galectin-1 mRNA levels in mouse lung tissue peak at postnatal day 6. Immunoblot analysis confirmed that peak levels of lung galectin-1 protein are found at postnatal days 6 to 12. The increased expression of galectin-1 at the site and time of ongoing alveolarization in the newborn mouse is suggestive that galectin-1 may play an important role in this critical aspect of lung development.

Past, present and future of gene expression-tailored therapy for lung cancer

“Variability is the law of life, and as no two faces are the same, so no two bodies are alike, and no two individuals react alike and behave alike under the abnormal conditions which we know as disease.” Sir William Osler (1849–1919). All human beings are different and some of these differences are the variations in response to xenobiotics. Personalized medicine means: the right patient population, the right drug, the right dose, the right indication, and administration at the right time. This review provides an update on concepts of personalized therapy for lung cancer.