Epithelial barrier homeostasis

Abstract

Epithelia cover the body's surface to form a barrier that segregates the internal body from the external environment. Tight junctions (TJs) seal the paracellular space and are crucial for the formation of the epithelial barrier. Epithelial barrier integrity is challenged by mechanical stress, infection, genetic lesions, or inflammation, and epithelial barrier defects must be prevented or repaired to maintain epithelial barrier homeostasis. Recent research is starting to uncover the molecular mechanisms underlying epithelial barrier homeostasis. This review provides an overview of how epithelial barrier defects are prevented and repaired and discusses the pathophysiological roles of epithelial barrier homeostasis. Furthermore, recent findings showing that epithelial barrier defects may occur in a controlled manner to facilitate bulk paracellular transport are discussed.

Keywords: Rho signaling; cell competition; cell extrusion; epithelial barrier; epithelial homeostasis; tight junctions.