title: Keeping it together: Pulmonary alveoli are maintained by a hierarchy of cellular programs.
abstract: The application of in vivo genetic lineage tracing has advanced our understanding of cellular mechanisms for tissue renewal in organs with slow turnover, like the lung. These studies have identified an adult stem cell with very different properties than classically understood ones that maintain continuously cycling tissues such as the intestine. A portrait has emerged of an ensemble of cellular programs that replenish the cells that line the gas exchange (alveolar) surface, enabling a response tailored to the extent of cell loss. A capacity for differentiated cells to undergo direct lineage transitions allows for local restoration of proper cell balance at sites of injury. We present these recent findings as a paradigm for how a relatively quiescent tissue compartment can maintain homeostasis throughout a lifetime punctuated by injuries ranging from mild to life-threatening, and discuss how dysfunction or insufficiency of alveolar repair programs produce serious health consequences like cancer and fibrosis.
authors.affiliation: Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA, USA.
authors.forename: Catriona Y
authors.initials: CY
authors.lastname: Logan
authors.affiliation: Department of Internal Medicine, Pulmonary and Critical Care, Stanford University School of Medicine, Stanford, CA, USA.
authors.forename: Tushar J
authors.initials: TJ
authors.lastname: Desai
mesh_terms: D000818:Animals; D001980:Bronchi / Q000502:physiology; D005740:Gases / Q000378:metabolism; D006801:Humans; D009369:Neoplasms / Q000473:pathology; D010641:Phenotype; D011650:Pulmonary Alveoli / Q000166:cytology* / Q000502:physiology*; D013234:Stem Cells / Q000166:cytology
chemical_list: D005740:Gases
keywords: AT2 cell; alveoli; lineage tracing; lung; repair; stem cell; transdifferentiation