How epithelial cells detect danger: aiding the immune response

Abstract

The epithelial layer occupies a strategic important location between an organisms’ interior and exterior environment. Although as such it forms a physical barrier between both environments, it became clear that the role of the epithelium extends far beyond this rather passive role. Through specialized receptors and other more general mechanisms, the epithelial layer is not only able to sense changes in its environment but also to actively respond to these changes. These responses allow the epithelium to contribute to wound and tissue repair, to the defense against micro‐organisms, and to the control and regulation of the locale immune response. In this review, we focus on signals acting on epithelium from the exterior environment, how these signals are processed and identify research challenges.

International Consensus Statement on Allergy and Rhinology: Rhinosinusitis

“…528 In addition to host defense molecules, ECs respond to PRR stimulation with the secretion of cytokines and chemokines that foster inflammation and attract and activate innate effector cells. 362,515,[529][530][531][532] In addition, the EC cytokines play a key role in shaping any subsequent adaptive immune response. Cytokine crosstalk between ECs, innate lymphoid cells (ILCs), and dendritic cells matches the appropriate innate and adaptive response to particular foreign stimuli.…”

“…These proteases trigger release of mediators responsible for damage of host tissue. [362][363][364] Further, Alternaria can directly activate eosinophils leading to production of IL-8 and surface expression of eosinophil receptors key to cellular adhesion. 365 Immunologic responses to fungi have been observed in patients with CRS.…”

Flaky Tail Mouse as a Novel Animal Model of Atopic Dermatitis: Possible Roles of Filaggrin in the Development of Atopic Dermatitis

“…The SC serves as a biosensor of the external environment and a link between innate and adaptive immune systems (Vroling, et al, 2008). The critical association between the abnormal barrier in AD and Th2 polarization may in part be explained by the production of the cytokine, thymic stromal lymphopoietin (TSLP) (Ebner, et al, 2007).…”

Effects of simulated weightlessness on tight junction protein occludin and Zonula Occluden-1 expression levels in the intestinal mucosa of rats

“…Disruption of the TJs can cause increased permeability, leading to "leakiness". Molecules which were normally excluded were then passed the mucosal epithelium by paracellular permeation, resulting in inflammatory conditions in the mucosa [6] .…”