title: Alpha-enolase on apical surface of renal tubular epithelial cells serves as a calcium oxalate crystal receptor.
abstract: To search for a strategy to prevent kidney stone formation/recurrence, this study addressed the role of α-enolase on apical membrane of renal tubular cells in mediating calcium oxalate monohydrate (COM) crystal adhesion. Its presence on apical membrane and in COM crystal-bound fraction was confirmed by Western blotting and immunofluorescence staining. Pretreating MDCK cells with anti-α-enolase antibody, not isotype-controlled IgG, dramatically reduced cell-crystal adhesion. Immunofluorescence staining also confirmed the direct binding of purified α-enolase to COM crystals at {121} > {100} > {010} crystal faces. Coating COM crystals with urinary proteins diminished the crystal binding capacity to cells and purified α-enolase. Moreover, α-enolase selectively bound to COM, not other crystals. Chemico-protein interactions analysis revealed that α-enolase interacted directly with Ca2+and Mg2+. Incubating the cells with Mg2+prior to cell-crystal adhesion assay significantly reduced crystal binding on the cell surface, whereas preincubation with EDTA, a divalent cation chelator, completely abolished Mg2+effect, indicating that COM and Mg2+competitively bind to α-enolase. Taken together, we successfully confirmed the role of α-enolase as a COM crystal receptor to mediate COM crystal adhesion at apical membrane of renal tubular cells. It may also serve as a target for stone prevention by blocking cell-crystal adhesion and stone nidus formation.
authors: Medical Proteomics Unit, Office for Research and Development, Faculty of Medicine Siriraj Hospital, and Center for Research in Complex Systems Science, Mahidol University, Bangkok, Thailand.
authors: Kedsarin
authors: K
authors: Fong-Ngern
authors: Medical Proteomics Unit, Office for Research and Development, Faculty of Medicine Siriraj Hospital, and Center for Research in Complex Systems Science, Mahidol University, Bangkok, Thailand.
authors: Visith
authors: V
authors: Thongboonkerd
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology; D002129:Calcium Oxalate / Q000737:chemistry* / Q000378:metabolism; D002130:Calcium Phosphates / Q000737:chemistry / Q000378:metabolism; D002448:Cell Adhesion; D002462:Cell Membrane / Q000378:metabolism; D003460:Crystallization; D004285:Dogs; D017886:Durapatite / Q000737:chemistry / Q000378:metabolism; D061985:Madin Darby Canine Kidney Cells; D008856:Microscopy, Fluorescence; D008858:Microscopy, Phase-Contrast; D010751:Phosphopyruvate Hydratase / Q000276:immunology / Q000378:metabolism*; D011485:Protein Binding
chemical_list: D000906:Antibodies; D002130:Calcium Phosphates; D002129:Calcium Oxalate; D017886:Durapatite; D010751:Phosphopyruvate Hydratase; C494366:calcium phosphate, dibasic, dihydrate