title: p38 MAPK mediates calcium oxalate crystal-induced tight junction disruption in distal renal tubular epithelial cells.
abstract: We examined whether p38 MAPK plays role in calcium oxalate monohydrate (COM) crystal-induced tight junction disruption. Polarized MDCK cells were pretreated with or without 20 μM SB239063 (p38 MAPK inhibitor) for 2-h, and then incubated with 100 μg/ml COM crystals for up to 48-h. Western blotting showed increased level of phospho-p38, not total p38, in COM-treated cells, whereas SB239063 pretreatment successfully maintained phospho-p38 at its basal level. COM crystals also caused decreased levels of two tight junction proteins, zonula occludens-1 (ZO-1) and occludin. Immunofluorescence study revealed disruption of tight junction, redistribution, and dissociation of ZO-1 and occludin. Moreover, transepithelial resistance (TER) showed defective barrier function, whereas Western blotting for Na(+)/K(+)-ATPase-α1 revealed defective fence function of tight junction in COM-treated cells. All these expression and functional defects were successfully prevented by SB239063 pretreatment. These findings indicate that COM crystals cause tight junction disruption in distal renal tubular epithelial cells through p38 MAPK activation.
authors.affiliation: Medical Proteomics Unit, Office for Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Paleerath
authors.initials: P
authors.lastname: Peerapen
authors.forename: Visith
authors.initials: V
authors.lastname: Thongboonkerd
mesh_terms: D000818:Animals; D002129:Calcium Oxalate / Q000737:chemistry / Q000633:toxicity*; D016764:Cell Polarity / Q000187:drug effects; D003460:Crystallization; D004285:Dogs; D006861:Hydrogen Peroxide / Q000378:metabolism; D061985:Madin Darby Canine Kidney Cells; D062793:Occludin / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D019108:Tight Junctions / Q000187:drug effects* / Q000378:metabolism; D062826:Zonula Occludens-1 Protein / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D062793:Occludin; D047428:Protein Kinase Inhibitors; D062826:Zonula Occludens-1 Protein; D002129:Calcium Oxalate; D006861:Hydrogen Peroxide; D048051:p38 Mitogen-Activated Protein Kinases; D000254:Sodium-Potassium-Exchanging ATPase