title: The cardiac hypoxic niche: emerging role of hypoxic microenvironment in cardiac progenitors.
abstract: Resident stem cells persist throughout the entire lifetime of an organism where they replenishing damaged cells. Numerous types of resident stem cells are housed in a low-oxygen tension (hypoxic) microenvironment, or niches, which seem to be critical for survival and maintenance of stem cells. Recently our group has identified the adult mammalian epicardium and subepicardium as a hypoxic niche for cardiac progenitor cells. Similar to hematopoietic stem cells (LT-HSCs), progenitor cells in the hypoxic epicardial niche utilize cytoplasmic glycolysis instead of mitochondrial oxidative phosphorylation, where hypoxia inducible factor 1α (Hif-1α) maintains them in glycolytic undifferentiated state. In this review we summarize the relationship between hypoxic signaling and stem cell function, and discuss potential roles of several cardiac stem/progenitor cells in cardiac homeostasis and regeneration.
authors.affiliation: Department of Internal Medicine, Division of Cardiology, UT Southwestern Medical Center, Dallas, TX, USA.
authors.forename: Wataru
authors.initials: W
authors.lastname: Kimura
authors.forename: Hesham A
authors.initials: HA
authors.lastname: Sadek
keywords: Hypoxic microenvironment; cardiac progenitors; hematopoietic stem cells (LT-HSCs); hypoxia inducible factor 1a (Hif-1a)