Acid is a major cause of gastro-esophageal reflux disease. However, the influence of acid on the esophageal stratified epithelial barrier function and tight junction (TJ) proteins is not fully understood. Here, we explore the influence of acid on barrier function and TJ proteins using a newly developed model of the esophageal-like squamous epithelial cell layers that employs an air-liquid interface (ALI) system. Barrier function was determined by measuring trans-epithelial electrical resistance (TEER) and diffusion of paracellular tracers. TJ-related protein (claudin-1, claudin-4, occludin and ZO-1) expression and localization was examined by immunofluorescent staining, and by western blotting of 1% NP-40 soluble and insoluble fractions. We also examined the influence of acid (pH 2-4) on the barrier created by these cells. The in vitro ALI culture system showed a tight barrier (1500-2500 Ω·cm(2)) with the expression of claudin-1, claudin-4, occludin and ZO-1 in the superficial layers. Claudin-1, claudin-4, occludin and ZO-1 were detected as dots and whisker-like lines in the superficial layers, and as a broad line in the suprabasal layers. These localization patterns are similar to those in the human esophagus. On day 7 under ALI culture, TJ proteins were detected in the superficial layers with functional properties, including decreased permeability and increased TEER. Dilated intercellular spaces were detected at the suprabasal cell layers even under the control conditions of ALI cells. pH 2 acid on the apical side significantly reduced the TEER in ALI-cultured cells. This decrease in TEER by the acid was in parallel with the decreased amount of detergent-insoluble claudin-4. Claudin-4 delocalization was confirmed by immunofluorescent staining. In conclusion, TJs are located in the superficial layers of the esophagus, and acid stimulation disrupts barrier function, at least in part by modulating the amount and localization of claudin-4 in the superficial layers.
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http://dx.doi.org/10.1038/labinvest.2011.139 | DOI Listing |
Alzheimers Dement
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Amsterdam Neuroscience, Brain Imaging, Amsterdam, Netherlands.
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December 2024
Department of Clinical Neurosciences and Cambridge University Hospitals NHS Trust, University of Cambridge, Cambridge, United Kingdom.
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Keio University Faculty of Medicine, Department of Ophthalmology, Tokyo, Japan.
In vivo confocal microscopy (IVCM) is a non-invasive imaging technique used to visualize the layers of the cornea and conjunctiva in real time. In patients with atopic keratoconjunctivitis (AKC) and vernal keratoconjunctivitis (VKC), this technology can be useful in diagnosing and monitoring the disease, as well as evaluating the efficacy of treatments. IVCM can reveal subclinical abnormalities in the corneal and conjunctival epithelium such as inflammatory cell infiltrates and tissue damage, which can provide insight into the pathogenesis of AKC.
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December 2024
Weldon School of Biomedical Engineering, West Lafayette, Indiana, IN, USA.
Circuit-based biomarkers distinguishing the gradual progression of Lewy pathology across synucleinopathies remain unknown. Here, we show that seeding of α-synuclein preformed fibrils in mouse dorsal striatum and motor cortex leads to distinct prodromal-phase cortical dysfunction across months. Our findings reveal that while both seeding sites had increased cortical pathology and hyperexcitability, distinct differences in electrophysiological and cellular ensemble patterns were crucial in distinguishing pathology spread between the two seeding sites.
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December 2024
School of Chemistry, Faculty of Engineering and Physical Sciences, University of Southampton, Life Sciences Building 85, University Road, Highfield, Southampton, SO17 1BJ, UK.
Osteoarthritis (OA) is a complex disease of cartilage characterised by joint pain, functional limitation, and reduced quality of life with affected joint movement leading to pain and limited mobility. Current methods to diagnose OA are predominantly limited to X-ray, MRI and invasive joint fluid analysis, all of which lack chemical or molecular specificity and are limited to detection of the disease at later stages. A rapid minimally invasive and non-destructive approach to disease diagnosis is a critical unmet need.
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