title: Shedding of klotho by ADAMs in the kidney.
abstract: The anti-aging gene klotho plays an important role in Ca(2+) and phosphate homeostasis. Membrane-bound klotho is an essential coreceptor for fibroblast growth factor-23 and can be cleaved by proteases, including a disintegrin and metalloproteinase (ADAM)10 and ADAM17. Cleavage of klotho occurs at a site directly above the plasma membrane (α-cut) or between the KL1 and KL2 domain (β-cut), resulting in soluble full-length klotho or KL1 and KL2 fragments, respectively. The aim of the present study was to gain insights into the mechanisms behind klotho cleavage processes in the kidney. Klotho shedding was demonstrated using a Madin-Darby canine kidney cell line stably expressing klotho and human embryonic kidney-293 cells transiently transfected with klotho. Here, we report klotho expression on both the basolateral and apical membrane, with a higher abundance of klotho at the apical membrane and in the apical media. mRNA expression of ADAM17 and klotho were enriched in mouse distal convoluted and connecting tubules. In vitro ADAM/matrix metalloproteinase inhibition by TNF484 resulted in a concentration-dependent inhibition of the α-cut, with a less specific effect on β-cut shedding. In vivo TNF484 treatment in wild-type mice did not change urinary klotho levels. However, ADAM/matrix metalloproteinase inhibition did increase renal and duodenal mRNA expression of phosphate transporters, whereas serum phosphate levels were significantly decreased. In conclusion, our data show that renal cells preferentially secrete klotho to the apical side and suggest that ADAMs are responsible for α-cut cleavage.
authors.affiliation: Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands;
authors.forename: Ellen P M
authors.initials: EP
authors.lastname: van Loon
authors.affiliation: Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands;
authors.forename: Wilco P
authors.initials: WP
authors.lastname: Pulskens
authors.affiliation: Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands;
authors.forename: Eline A E
authors.initials: EA
authors.lastname: van der Hagen
authors.affiliation: Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands;
authors.forename: Marla
authors.initials: M
authors.lastname: Lavrijsen
authors.affiliation: Department of Nephrology, VU University Medical Center, Amsterdam, The Netherlands; and.
authors.forename: Marc G
authors.initials: MG
authors.lastname: Vervloet
authors.affiliation: Department of Pathology and Medical Biology, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Harry
authors.initials: H
authors.lastname: van Goor
authors.affiliation: Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands;
authors.forename: René J M
authors.initials: RJ
authors.lastname: Bindels
authors.affiliation: Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands; Joost.Hoenderop@radboudumc.nl.
authors.forename: Joost G J
authors.initials: JG
authors.lastname: Hoenderop
mesh_terms: D051722:ADAM Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000072197:ADAM10 Protein; D000072198:ADAM17 Protein; D053829:Amyloid Precursor Protein Secretases / Q000235:genetics / Q000378:metabolism; D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology*; D017077:Culture Media, Conditioned / Q000378:metabolism; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004386:Duodenum / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D005966:Glucuronidase / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D007668:Kidney / Q000187:drug effects / Q000201:enzymology*; D000090265:Klotho Proteins; D061985:Madin Darby Canine Kidney Cells; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008810:Mice, Inbred C57BL; D028061:Phosphate Transport Proteins / Q000378:metabolism; D010710:Phosphates / Q000097:blood; D011480:Protease Inhibitors / Q000494:pharmacology; D011499:Protein Processing, Post-Translational; D012333:RNA, Messenger / Q000378:metabolism; D014162:Transfection
chemical_list: D017077:Culture Media, Conditioned; D008565:Membrane Proteins; D028061:Phosphate Transport Proteins; D010710:Phosphates; D011480:Protease Inhibitors; D012333:RNA, Messenger; D005966:Glucuronidase; D000090265:Klotho Proteins; D053829:Amyloid Precursor Protein Secretases; D051722:ADAM Proteins; D000072197:ADAM10 Protein; C491234:Adam10 protein, mouse; D000072198:ADAM17 Protein; C000606462:ADAM17 protein, human; C000606463:Adam17 protein, mouse
keywords: a disintegrin and metalloproteinase 10; a disintegrin and metalloproteinase 17; a disintegrin and metalloproteinase/matrix metalloproteinase inhibitor; klotho; klotho shedding