title: Shedding of Endogenous Interleukin-6 Receptor (IL-6R) Is Governed by A Disintegrin and Metalloproteinase (ADAM) Proteases while a Full-length IL-6R Isoform Localizes to Circulating Microvesicles.
abstract: Generation of the soluble interleukin-6 receptor (sIL-6R) is a prerequisite for pathogenic IL-6 trans-signaling, which constitutes a distinct signaling pathway of the pleiotropic cytokine interleukin-6 (IL-6). Although in vitro experiments using ectopically overexpressed IL-6R and candidate proteases revealed major roles for the metalloproteinases ADAM10 and ADAM17 in IL-6R shedding, the identity of the protease(s) cleaving IL-6R in more physiological settings, or even in vivo, remains unknown. By taking advantage of specific pharmacological inhibitors and primary cells from ADAM-deficient mice we established that endogenous IL-6R of both human and murine origin is shed by ADAM17 in an induced manner, whereas constitutive release of endogenous IL-6R is largely mediated by ADAM10. Although circulating IL-6R levels are altered in various diseases, the origin of blood-borne IL-6R is still poorly understood. It has been shown previously that ADAM17 hypomorphic mice exhibit unaltered levels of serum sIL-6R. Here, by quantification of serum sIL-6R in protease-deficient mice as well as human patients we also excluded ADAM10, ADAM8, neutrophil elastase, cathepsin G, and proteinase 3 from contributing to circulating sIL-6R. Furthermore, we ruled out alternative splicing of the IL-6R mRNA as a potential source of circulating sIL-6R in the mouse. Instead, we found full-length IL-6R on circulating microvesicles, establishing microvesicle release as a novel mechanism for sIL-6R generation.
authors.affiliation: From the Institute of Biochemistry, Medical Faculty, University of Kiel, Rudolf-Höber-Str. 1, 24118 Kiel, Germany.
authors.forename: Neele
authors.initials: N
authors.lastname: Schumacher
authors.affiliation: From the Institute of Biochemistry, Medical Faculty, University of Kiel, Rudolf-Höber-Str. 1, 24118 Kiel, Germany.
authors.forename: Dörte
authors.initials: D
authors.lastname: Meyer
authors.affiliation: From the Institute of Biochemistry, Medical Faculty, University of Kiel, Rudolf-Höber-Str. 1, 24118 Kiel, Germany.
authors.forename: Andre
authors.initials: A
authors.lastname: Mauermann
authors.affiliation: From the Institute of Biochemistry, Medical Faculty, University of Kiel, Rudolf-Höber-Str. 1, 24118 Kiel, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: von der Heyde
authors.affiliation: From the Institute of Biochemistry, Medical Faculty, University of Kiel, Rudolf-Höber-Str. 1, 24118 Kiel, Germany.
authors.forename: Janina
authors.initials: J
authors.lastname: Wolf
authors.affiliation: From the Institute of Biochemistry, Medical Faculty, University of Kiel, Rudolf-Höber-Str. 1, 24118 Kiel, Germany.
authors.forename: Jeanette
authors.initials: J
authors.lastname: Schwarz
authors.affiliation: From the Institute of Biochemistry, Medical Faculty, University of Kiel, Rudolf-Höber-Str. 1, 24118 Kiel, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Knittler
authors.affiliation: the Department of Oncology, University of Cambridge, Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, United Kingdom.
authors.forename: Gillian
authors.initials: G
authors.lastname: Murphy
authors.affiliation: From the Institute of Biochemistry, Medical Faculty, University of Kiel, Rudolf-Höber-Str. 1, 24118 Kiel, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Michalek
authors.affiliation: From the Institute of Biochemistry, Medical Faculty, University of Kiel, Rudolf-Höber-Str. 1, 24118 Kiel, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Garbers
authors.affiliation: the Department of Neurosurgery/Lab, Philipps-University Marburg, Baldingerstr., 35033 Marburg, Germany, and.
authors.forename: Jörg W
authors.initials: JW
authors.lastname: Bartsch
authors.affiliation: the Department of Neurosurgery/Lab, Philipps-University Marburg, Baldingerstr., 35033 Marburg, Germany, and.
authors.forename: Songbo
authors.initials: S
authors.lastname: Guo
authors.affiliation: the Department of Periodontology, Center for Dentistry and Oral Medicine (Carolinum), Johann Wolfgang Goethe-University, Theodor-Stern-Kai 7, 60596 Frankfurt am Main, Germany.
authors.forename: Beate
authors.initials: B
authors.lastname: Schacher
authors.affiliation: the Department of Periodontology, Center for Dentistry and Oral Medicine (Carolinum), Johann Wolfgang Goethe-University, Theodor-Stern-Kai 7, 60596 Frankfurt am Main, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Eickholz
authors.affiliation: From the Institute of Biochemistry, Medical Faculty, University of Kiel, Rudolf-Höber-Str. 1, 24118 Kiel, Germany.
authors.forename: Athena
authors.initials: A
authors.lastname: Chalaris
authors.affiliation: From the Institute of Biochemistry, Medical Faculty, University of Kiel, Rudolf-Höber-Str. 1, 24118 Kiel, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Rose-John
authors.affiliation: From the Institute of Biochemistry, Medical Faculty, University of Kiel, Rudolf-Höber-Str. 1, 24118 Kiel, Germany, brabe@biochem.uni-kiel.de.
authors.forename: Björn
authors.initials: B
authors.lastname: Rabe
mesh_terms: D051722:ADAM Proteins / Q000378:metabolism*; D000072197:ADAM10 Protein; D000072198:ADAM17 Protein; D053829:Amyloid Precursor Protein Secretases / Q000378:metabolism*; D000818:Animals; D002460:Cell Line; D006801:Humans; D008070:Lipopolysaccharides / Q000494:pharmacology; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism; D020033:Protein Isoforms / Q000378:metabolism*; D059748:Proteolysis; D012326:RNA Splicing; D019947:Receptors, Interleukin-6 / Q000235:genetics / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D008070:Lipopolysaccharides; D008565:Membrane Proteins; D020033:Protein Isoforms; D019947:Receptors, Interleukin-6; D053829:Amyloid Precursor Protein Secretases; D051722:ADAM Proteins; D000072197:ADAM10 Protein; C491236:ADAM10 protein, human; D000072198:ADAM17 Protein; C000606462:ADAM17 protein, human; C000606463:Adam17 protein, mouse; D013755:Tetradecanoylphorbol Acetate
keywords: ADAM; ADAM10; ADAM17; exosomes; interleukin 6 (IL-6); interleukin 6 receptor (IL6R); microvesicles; protease; shedding