@article{nighot_moeser_ryan_ghashghaei_blikslager_2009, title={ClC-2 is required for rapid restoration of epithelial tight junctions in ischemic-injured murine jejunum}, volume={315}, ISSN={0014-4827}, url={http://dx.doi.org/10.1016/j.yexcr.2008.10.001}, DOI={10.1016/j.yexcr.2008.10.001}, abstractNote={Involvement of the epithelial chloride channel ClC-2 has been implicated in barrier recovery following ischemic injury, possibly via a mechanism involving ClC-2 localization to the tight junction. The present study investigated mechanisms of intestinal barrier repair following ischemic injury in ClC-2(-/-) mice.Wild type, ClC-2 heterozygous and ClC-2(-/-) murine jejunal mucosa was subjected to complete ischemia, after which recovery of barrier function was monitored by measuring in vivo blood-to-lumen clearance of (3)H-mannitol. Tissues were examined by light and electron microscopy. The role of ClC-2 in re-assembly of the tight junction during barrier recovery was studied by immunoblotting, immunolocalization and immunoprecipitation.Following ischemic injury, ClC-2(-/-) mice had impaired barrier recovery compared to wild type mice, defined by increases in epithelial paracellular permeability independent of epithelial restitution. The recovering ClC-2(-/-) mucosa also had evidence of ultrastructural paracellular defects. The tight junction proteins occludin and claudin-1 shifted significantly to the detergent soluble membrane fraction during post-ischemic recovery in ClC-2(-/-) mice whereas wild type mice had a greater proportion of junctional proteins in the detergent insoluble fraction. Occludin was co-immunoprecipitated with ClC-2 in uninjured wild type mucosa, and the association between occludin and ClC-2 was re-established during ischemic recovery. Based on immunofluorescence studies, re-localization of occludin from diffuse sub-apical areas to apical tight junctions was impaired in ClC-2(-/-) mice.These data demonstrate a pivotal role of ClC-2 in recovery of the intestinal epithelium barrier by anchoring assembly of tight junctions following ischemic injury.}, number={1}, journal={Experimental Cell Research}, publisher={Elsevier BV}, author={Nighot, Prashant K. and Moeser, Adam J. and Ryan, Kathleen A. and Ghashghaei, Troy and Blikslager, Anthony T.}, year={2009}, month={Jan}, pages={110–118} }
 @article{wooten_blikslager_ryan_marks_law_lascelles_2008, title={Cyclooxygenase expression and prostanoid production in pyloric and duodenal mucosae in dogs after administration of nonsteroidal anti-inflammatory drugs}, volume={69}, ISSN={0002-9645}, url={http://dx.doi.org/10.2460/ajvr.69.4.457}, DOI={10.2460/ajvr.69.4.457}, abstractNote={Abstract}, number={4}, journal={American Journal of Veterinary Research}, publisher={American Veterinary Medical Association (AVMA)}, author={Wooten, Jenna G. and Blikslager, Anthony T. and Ryan, Kathleen A. and Marks, Steve L. and Law, J. Mac and Lascelles, B. Duncan X.}, year={2008}, month={Apr}, pages={457–464} }
 @article{moeser_nighot_ryan_simpson_clarke_blikslager_2008, title={Mice lacking the Na+/H+ exchanger 2 have impaired recovery of intestinal barrier function}, volume={295}, ISSN={0193-1857 1522-1547}, url={http://dx.doi.org/10.1152/ajpgi.00538.2007}, DOI={10.1152/ajpgi.00538.2007}, abstractNote={ Ischemic injury induces breakdown of the intestinal barrier. Recent studies in porcine postischemic tissues indicate that inhibition of NHE2 results in enhanced recovery of barrier function in vitro via a process involving interepithelial tight junctions. To further study this process, recovery of barrier function was assessed in wild-type (NHE2+/+) and NHE2−/− mice in vivo and wild-type mice in vitro. Mice were subjected to complete mesenteric ischemia in vivo, after which barrier function was measured by blood-to-lumen mannitol clearance over a 3-h recovery period or measurement of transepithelial electrical resistance (TER) in Ussing chambers immediately following ischemia. Tissues were assessed for expression of select junctional proteins. Compared with NHE2+/+ mice, NHE2−/− mice had greater intestinal permeability during the postischemic recovery process. In contrast to prior porcine studies, pharmacological inhibition of NHE2 in postischemic tissues from wild-type mice also resulted in significant reductions in TER. Mucosa from NHE2−/− mice displayed a shift of occludin and claudin-1 expression to the Triton-X-soluble membrane fractions and showed disruption of occludin and claudin-1 localization patterns following injury. This was qualitatively and quantitatively recovered in NHE2+/+ mice compared with NHE2−/− mice by the end of the 3-h recovery period. Serine phosphorylation of occludin and claudin-1 was downregulated in NHE2−/− postischemia compared with wild-type mice. These data indicate an important role for NHE2 in recovery of barrier function in mice via a mechanism involving tight junctions. }, number={4}, journal={American Journal of Physiology-Gastrointestinal and Liver Physiology}, publisher={American Physiological Society}, author={Moeser, Adam J. and Nighot, Prashant K. and Ryan, Kathleen A. and Simpson, Janet E. and Clarke, Lane L. and Blikslager, Anthony T.}, year={2008}, month={Oct}, pages={G791–G797} }
 @article{moeser_ryan_nighot_blikslager_2007, title={Gastrointestinal dysfunction induced by early weaning is attenuated by delayed weaning and mast cell blockade in pigs}, volume={293}, ISSN={0193-1857 1522-1547}, url={http://dx.doi.org/10.1152/ajpgi.00304.2006}, DOI={10.1152/ajpgi.00304.2006}, abstractNote={Our previous work has demonstrated that weaning at 19 days of age has deleterious effects on mucosal barrier function in piglet intestine that are mediated through peripheral CRF receptor signaling pathways. The objectives of the present study were to assess the impact of piglet age on weaning-associated intestinal dysfunction and to determine the role that mast cells play in weaning-induced breakdown of mucosal barrier function. Nursing Yorkshire-cross piglets were either weaned at 19 days of age (early-weaned, n = 8) or 28 days of age (late-weaned, n = 8) and housed in nursery pens. Twenty-four hours postweaning, segments of midjejunum and ascending colon from piglets within each weaning age group were harvested and mounted on Ussing chambers for measurements of transepithelial electrical resistance and serosal-to-mucosal [3H]mannitol fluxes. Early weaning resulted in reductions in transepithelial electrical resistance and increases in mucosal permeability to [3H]mannitol in the jejunum and colon ( P < 0.01). In contrast, postweaning reductions in intestinal barrier function were not observed in piglets weaned at 28 days of age. Early-weaned piglet intestinal mucosa had increased expression of CRF receptor 1 protein, increased mucosal mast cell tryptase levels, and evidence of enhanced mast cell degranulation compared with late-weaned intestinal mucosa. Pretreatment of piglets with the mast cell stabilizer drug cromolyn, injected intraperitoneally 30 min prior to weaning, abolished the early-weaning-induced intestinal barrier disturbances. Our results indicate that early-weaning stress induces mucosal dysfunction mediated by intestinal mast cell activation and can be prevented by delaying weaning.}, number={2}, journal={American Journal of Physiology-Gastrointestinal and Liver Physiology}, publisher={American Physiological Society}, author={Moeser, Adam J. and Ryan, Kathleen A. and Nighot, Prashant K. and Blikslager, Anthony T.}, year={2007}, month={Aug}, pages={G413–G421} }
 @article{moeser_klok_ryan_wooten_little_cook_blikslager_2007, title={Stress signaling pathways activated by weaning mediate intestinal dysfunction in the pig}, volume={292}, ISSN={0193-1857 1522-1547}, url={http://dx.doi.org/10.1152/ajpgi.00197.2006}, DOI={10.1152/ajpgi.00197.2006}, abstractNote={Weaning in the piglet is a stressful event associated with gastrointestinal disorders and increased disease susceptibility. Although stress is thought to play a role in postweaning intestinal disease, the mechanisms by which stress influences intestinal pathophysiology in the weaned pig are not understood. The objectives of these experiments were to investigate the impact of weaning on gastrointestinal health in the pig and to assess the role of stress signaling pathways in this response. Nineteen-day-old pigs were weaned, and mucosal barrier function and ion transport were assessed in jejunal and colonic tissues mounted on Ussing chambers. Weaning caused marked disturbances in intestinal barrier function, as demonstrated by significant ( P < 0.01) reductions in transepithelial electrical resistance and increases in intestinal permeability to [3H]mannitol in both the jejunum and colon compared with intestinal tissues from age-matched, unweaned control pigs. Weaned intestinal tissues exhibited increased intestinal secretory activity, as demonstrated by elevated short-circuit current that was sensitive to treatment with tetrodotoxin and indomethacin, suggesting activation of enteric neural and prostaglandin synthesis pathways in weaned intestinal tissues. Western blot analyses of mucosal homogenates showed increased expression of corticotrophin-releasing factor (CRF) receptor 1 in the jejunum and colon of weaned intestinal tissues. Pretreatment of pigs with the CRF receptor antagonist α-helical CRF(9–41), which was injected intraperitoneally 30 min prior to weaning, abolished the stress-induced mucosal changes. Our results indicate that weaning stress induces mucosal dysfunction mediated by intestinal CRF receptors and activated by enteric nerves and prostanoid pathways.}, number={1}, journal={American Journal of Physiology-Gastrointestinal and Liver Physiology}, publisher={American Physiological Society}, author={Moeser, Adam J. and Klok, Carin Vander and Ryan, Kathleen A. and Wooten, Jenna G. and Little, Dianne and Cook, Vanessa L. and Blikslager, Anthony T.}, year={2007}, month={Jan}, pages={G173–G181} }
 @article{moeser_nighot_ryan_wooten_blikslager_2006, title={Prostaglandin-mediated inhibition of Na+/H+ exchanger isoform 2 stimulates recovery of barrier function in ischemia-injured intestine}, volume={291}, ISSN={0193-1857 1522-1547}, url={http://dx.doi.org/10.1152/ajpgi.00380.2005}, DOI={10.1152/ajpgi.00380.2005}, abstractNote={Prostaglandins stimulate repair of the ischemia-injured intestinal barrier in the porcine ileum through a mechanism involving cAMP-dependent Cl−secretion and inhibition of electroneutral Na+/H+exchanger (NHE) activity. In the present study, we focused on the role of individual NHE isoforms in the recovery of barrier function. Ischemia-injured porcine ileal mucosa was mounted on Ussing chambers. Short-circuit current ( Isc), transepithelial electrical resistance (TER), and isotopic fluxes of22Na were measured in response to PGE2and selective inhibitors of epithelial NHE isoforms. Immunoassays were used to assess the expression of NHE isoforms. Forty-five minutes of intestinal ischemia resulted in a 45% reduction in TER ( P < 0.01). Near-complete restitution occurred within 60 min. Inhibition of NHE2 with HOE-694 (25 μM) added to the mucosal surface of the injured ileum stimulated significant elevations in TER, independent of changes in Iscand histological evidence of restitution. Pharmacological inhibition of NHE3 or NHE1 with mucosal S-3226 (20 μM) or serosal cariporide (25 μM), respectively, had no effect. Ischemia-injured tissues treated with mucosal S-3226 or HOE-694 exhibited equivalent reductions in mucosal-to-serosal fluxes of22Na+(by ∼35%) compared with nontreated ischemia-injured control tissues ( P < 0.05). Intestinal ischemia resulted in increased expression of the cytoplasmic NHE regulatory factor EBP50 in NHE2 but not in NHE3 immunoprecipitates. Selective inhibition of NHE2, and not NHE3, induces recovery of barrier function in the ischemia-injured intestine.}, number={5}, journal={American Journal of Physiology-Gastrointestinal and Liver Physiology}, publisher={American Physiological Society}, author={Moeser, Adam J. and Nighot, Prashant K. and Ryan, Kathleen A. and Wooten, Jenna G. and Blikslager, Anthony T.}, year={2006}, month={Nov}, pages={G885–G894} }