The role of reactive oxygen species (ROS) in osmotic stress, dextran sulfate sodium (DSS) and cyclic stretch-induced tight junction (TJ) disruption was investigated in Caco-2 cell monolayers in vitro and restraint stress-induced barrier dysfunction in mouse colon in vivo. Live cell imaging showed that osmotic stress, cyclic stretch and DSS triggered rapid production of ROS in Caco-2 cell monolayers, which was blocked by depletion of intracellular Ca2+ by 1,2-bis-(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid. Knockdown of CaV1.3 or TRPV6 channels blocked osmotic stress and DSS-induced ROS production and attenuated TJ disruption and barrier dysfunction. N-Acetyl l-cysteine (NAC) and l-NG-Nitroarginine methyl ester (l-NAME) blocked stress-induced TJ disruption and barrier dysfunction. NAC and l-NAME also blocked stress-induced activation of c-Jun N-terminal kinase (JNK) and c-Src. ROS was colocalized with the mitochondrial marker in stressed cells. Cyclosporin A blocked osmotic stress and DSS-induced ROS production, barrier dysfunction, TJ disruption and JNK activation. Mitochondria-targeted Mito-TEMPO blocked osmotic stress and DSS-induced barrier dysfunction and TJ disruption. Chronic restraint stress in mice resulted in the elevation of intracellular Ca2+, activation of JNK and c-Src, and disruption of TJ in the colonic epithelium. Furthermore, corticosterone administration induced JNK and c-Src activation, TJ disruption and protein thiol oxidation in colonic mucosa. The present study demonstrates that oxidative stress is a common signal in the mechanism of TJ disruption in the intestinal epithelium by different types of cellular stress in vitro and bio behavioral stress in vivo.
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Cover Image
Cover Image
This confocal microscopic image of an intestinal epithelium exposed to osmotic stress shows localization of nuclei and distribution of tight junction proteins, occludin (green) and ZO-1 (red). Discontinuous junctional distribution of these proteins is an indicator of disrupted tight junctions. For more information please see study by Gangwar et al. in this issue, pages 731–749. Image provided by R.K. Rao
Calcium-mediated oxidative stress: a common mechanism in tight junction disruption by different types of cellular stress
Ruchika Gangwar, Avtar S. Meena, Pradeep K. Shukla, Archana S. Nagaraja, Piotr L. Dorniak, Sandeep Pallikuth, Christopher M. Waters, Anil Sood, RadhaKrishna Rao; Calcium-mediated oxidative stress: a common mechanism in tight junction disruption by different types of cellular stress. Biochem J 1 March 2017; 474 (5): 731–749. doi: https://doi.org/10.1042/BCJ20160679
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