Tight junction proteins and the epidermis

Abstract

Epithelia are found at the interfaces between body compartments where they act as selective permeability barriers that maintain the unique composition of the compartments on either side. Epithelial barrier function is dependent on tight junctions (TJs), which seal the intercellular or paracellular spaces but may permit selective permeability. In simple epithelia (one cell thick), the function of TJs is relatively well understood. By contrast, our understanding of TJ structure and function in stratified epithelia (e.g. the epidermis) is limited. This article briefly discusses what is known about TJs and their components in simple epithelia and speculates about their roles in the epidermis.

An update on the role of human dendritic cells in patients with atopic dermatitis

“…Among the latter, tight junctions represent transmembrane proteins, to which the claudin family belongs. 33 Claudins are capable of modulating of transepithelial electrical resistance to both maintain protection and disrupt skin barrier function. Claudin-1 plays an important role in the enhancement of barrier function.…”

Skin barrier in atopic dermatitis: beyond filaggrin

“…6 In skin diseases with altered keratinization, such as psoriasis and ichthyosis vulgaris, they are present even in the deeper layers of the epidermis. 21 …”

Contribution of Tight Junction Proteins to Ion, Macromolecule, and Water Barrier in Keratinocytes

“…However, lamellar body contents have also been hypothesized to form this barrier (Elias et al, 1977). For other ions, the role of TJs, neither in cultured keratinocytes nor in skin, has been determined, even though it was hypothesized that TJs in the epidermis are important for the formation of a Ca 2 þ -gradient (Kurasawa et al, 2011;O'Neill and Garrod, 2011;Kirschner et al, 2012). The TJ barrier function for intermediate-sized molecules, and macromolecules has been shown for fluorescein (332 Da; De Benedetto et al, 2011), as well as for 3, 4, and 40 kDa FITC-dextrans in cultured keratinocytes (Mertens et al, 2005;Yuki et al, 2007;Kirschner et al, 2011), and for a 557-Da tracer in skin (Furuse et al, 2002;Kirschner et al, 2010b).…”