title: EGCG decreases binding of calcium oxalate monohydrate crystals onto renal tubular cells via decreased surface expression of alpha-enolase.
abstract: Crystal retention on tubular cell surface inside renal tubules is considered as the earliest and crucial step for kidney stone formation. Therapeutics targeting this step would cease the development of kidney stone. This study thus aimed to investigate the potential role of epigallocatechin-3-gallate (EGCG), a major antioxidant found in green tea leaves, in the reduction of calcium oxalate monohydrate (COM) crystal binding onto renal tubular cells. Pretreatment of the cells with EGCG for up to 6 h significantly diminished crystal-binding capability in a dose-dependent manner. Indirect immunofluorescence assay without and with cell permeabilization followed by laser-scanning confocal microscopy revealed that EGCG significantly reduced surface expression of alpha-enolase, whereas its intracellular level was increased. Western blot analysis confirmed such contradictory changes in membrane and cytosolic fractions of EGCG-treated cells, whereas the total level in whole cell lysate remained unchanged. Moreover, overexpression of surface alpha-enolase and enhancement of cell-crystal adhesion induced by 10 mM sodium oxalate were completely abolished by EGCG. Taken together, these data indicate that EGCG decreases binding of COM crystals onto renal tubular cells by decreasing the surface expression of alpha-enolase via re-localization or inhibition of alpha-enolase shuttling from the cytoplasm to the plasma membrane. These findings may also explain the effects of EGCG in reducing COM crystal deposition in previous animal models of kidney stone disease. Thus, EGCG may be useful for the prevention of new or recurrent stone formation.
authors.affiliation: Medical Proteomics Unit, Office for Research and Development, Faculty of Medicine, Siriraj Hospital, Mahidol University, 6th Floor-SiMR Building, 2 Wanglang Road, Bangkoknoi, Bangkok, 10700, Thailand.|Center for Research in Complex Systems Science (CRCSS), Mahidol University, Bangkok, Thailand.
authors.forename: Rattiyaporn
authors.initials: R
authors.lastname: Kanlaya
authors.affiliation: Medical Proteomics Unit, Office for Research and Development, Faculty of Medicine, Siriraj Hospital, Mahidol University, 6th Floor-SiMR Building, 2 Wanglang Road, Bangkoknoi, Bangkok, 10700, Thailand.|Center for Research in Complex Systems Science (CRCSS), Mahidol University, Bangkok, Thailand.
authors.forename: Nilubon
authors.initials: N
authors.lastname: Singhto
authors.affiliation: Medical Proteomics Unit, Office for Research and Development, Faculty of Medicine, Siriraj Hospital, Mahidol University, 6th Floor-SiMR Building, 2 Wanglang Road, Bangkoknoi, Bangkok, 10700, Thailand. thongboonkerd@dr.com.|Center for Research in Complex Systems Science (CRCSS), Mahidol University, Bangkok, Thailand. thongboonkerd@dr.com.
authors.forename: Visith
authors.initials: V
authors.lastname: Thongboonkerd
mesh_terms: D000818:Animals; D001665:Binding Sites / Q000187:drug effects; D002129:Calcium Oxalate / Q000737:chemistry / Q000378:metabolism*; D002392:Catechin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D002478:Cells, Cultured; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D061985:Madin Darby Canine Kidney Cells; D010751:Phosphopyruvate Hydratase / Q000096:biosynthesis* / Q000737:chemistry / Q000172:deficiency*; D013329:Structure-Activity Relationship; D013499:Surface Properties
chemical_list: D002129:Calcium Oxalate; D002392:Catechin; C045651:epigallocatechin gallate; D010751:Phosphopyruvate Hydratase
keywords: Calcium oxalate; Crystal binding; EGCG; Enolase; Kidney stone; Renal tubular cells