Background
IL-1β is a cytokine involved in mediating epithelial barrier dysfunction in the gut. It is known that IL-1β mediates activation of non-muscle myosin light chain kinase in epithelial cells, but the precise mechanism by which epithelial barrier dysfunction is induced by IL-1β is not understood.
Methods and Results
Using a Caco2 cell model, we show that the expression of the tight junction protein, claudin-3, is transcriptionally downregulated by IL-1β treatment. In addition, after assessing protein and mRNA expression, and protein localization, we show that inhibition of nmMLCK rescues IL-1β mediated decrease in claudin-3 expression as well as junction protein redistribution. Using chromatin immunoprecipitation assays, we also show that β-catenin targeting of the claudin-3 promoter occurs as a consequence of IL-1β mediated epithelial barrier dysfunction, and inhibition of nmMLCK interferes with this interaction.
Conclusions
Taken together, this data represent the first line of evidence demonstrating nmMLCK regulation of claudin-3 expression in response to IL-1β treated epithelial cells.
In this paper we describe a new technique to measure the surface strain field on complex threedimensional structural components under static load. It is cost-efficient to implement and suitable to be integrated in the product design cycle in conjunction with finite element analysis tools. The technique employs novel luminescent photoelastic coatings and digital imaging to map the in-plane strain field. The coatings consist of a binder, generally polymeric in nature, and luminescent dyes that are applied to the surface of a test part using conventional aerosol techniques. When excited with circular polarized ultraviolet or blue illumination, the corresponding emission intensity from the coating is measured via a digital camera. The relative change in emission magnitude and phase as measured after passing through an analyzing polarizer is related to the in-plane shear strain and its corresponding principal direction. Several basic test results are presented and discussed, showing quantitative, repeatable, and high spatial resolution measurements.KEY WORDS--Luminescent, photoelastic coating, strain, full-field J.P. Hubner (SEM membe r; jphubner @ ufl. edu) is an Adjunct Associate Professor, P.G. 13~u (SEM member) is an Associate Professor, and L Chen (SEM member) is a Post-Doctorate Associate, cr = standard deviation co = angular frequency of light Subscripts avg = average ex = excitation c = combined em= emission f = fast axis H = horizontal orientation max = maximum np= non-polarized p = polarized or polarization q = quantum r = residual s = slow axis t = transmission or true V = vertical orientation 1 = primary in-plane principal direction 2 = secondary in-plane principal direction
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