title: The amino acid exchange R28E in ciliary neurotrophic factor (CNTF) abrogates interleukin-6 receptor-dependent but retains CNTF receptor-dependent signaling via glycoprotein 130 (gp130)/leukemia inhibitory factor receptor (LIFR).
abstract: Ciliary neurotrophic factor (CNTF) is a neurotrophic factor with therapeutic potential for neurodegenerative diseases. Moreover, therapeutic application of CNTF reduced body weight in mice and humans. CNTF binds to high or low affinity receptor complexes consisting of CNTFR·gp130·LIFR or IL-6R·gp130·LIFR, respectively. Clinical studies of the CNTF derivative Axokine revealed intolerance at higher concentrations, which may rely on the low-affinity binding of CNTF to the IL-6R. Here, we aimed to generate a CNTFR-selective CNTF variant (CV). CV-1 contained the single amino acid exchange R28E. Arg(28) is in close proximity to the CNTFR binding site. Using molecular modeling, we hypothesized that Arg(28) might contribute to IL-6R/CNTFR plasticity of CNTF. CV-2 to CV-5 were generated by transferring parts of the CNTFR-binding site from cardiotrophin-like cytokine to CNTF. Cardiotrophin-like cytokine selectively signals via the CNTFR·gp130·LIFR complex, albeit with a much lower affinity compared with CNTF. As shown by immunoprecipitation, all CNTF variants retained the ability to bind to CNTFR. CV-1, CV-2, and CV-5, however, lost the ability to bind to IL-6R. Although all variants induced cytokine-dependent cellular proliferation and STAT3 phosphorylation via CNTFR·gp130·LIFR, only CV-3 induced STAT3 phosphorylation via IL-6R·gp130·LIFR. Quantification of CNTF-dependent proliferation of CNTFR·gp130·LIFR expressing cells indicated that only CV-1 was as biologically active as CNTF. Thus, the CNTFR-selective CV-1 will allow discriminating between CNTFR- and IL-6R-mediated effects in vivo.
authors.affiliation: From the Institute of Biochemistry, Medical Faculty, Christian-Albrechts-University, 24098 Kiel, Germany and.
authors.forename: Eva-Maria
authors.initials: EM
authors.lastname: Wagener
authors.affiliation: From the Institute of Biochemistry, Medical Faculty, Christian-Albrechts-University, 24098 Kiel, Germany and.
authors.forename: Matthias
authors.initials: M
authors.lastname: Aurich
authors.affiliation: Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine-University, 40225 Düsseldorf, Germany.
authors.forename: Samadhi
authors.initials: S
authors.lastname: Aparicio-Siegmund
authors.affiliation: Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine-University, 40225 Düsseldorf, Germany.
authors.forename: Doreen M
authors.initials: DM
authors.lastname: Floss
authors.affiliation: From the Institute of Biochemistry, Medical Faculty, Christian-Albrechts-University, 24098 Kiel, Germany and.
authors.forename: Christoph
authors.initials: C
authors.lastname: Garbers
authors.affiliation: From the Institute of Biochemistry, Medical Faculty, Christian-Albrechts-University, 24098 Kiel, Germany and.
authors.forename: Kati
authors.initials: K
authors.lastname: Breusing
authors.affiliation: From the Institute of Biochemistry, Medical Faculty, Christian-Albrechts-University, 24098 Kiel, Germany and.
authors.forename: Björn
authors.initials: B
authors.lastname: Rabe
authors.affiliation: From the Institute of Biochemistry, Medical Faculty, Christian-Albrechts-University, 24098 Kiel, Germany and.
authors.forename: Ralf
authors.initials: R
authors.lastname: Schwanbeck
authors.affiliation: From the Institute of Biochemistry, Medical Faculty, Christian-Albrechts-University, 24098 Kiel, Germany and.
authors.forename: Joachim
authors.initials: J
authors.lastname: Grötzinger
authors.affiliation: From the Institute of Biochemistry, Medical Faculty, Christian-Albrechts-University, 24098 Kiel, Germany and.
authors.forename: Stefan
authors.initials: S
authors.lastname: Rose-John
authors.affiliation: Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine-University, 40225 Düsseldorf, Germany jscheller@uni-duesseldorf.de.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Scheller
mesh_terms: D019943:Amino Acid Substitution; D020934:Ciliary Neurotrophic Factor / Q000235:genetics* / Q000378:metabolism; D050822:Cytokine Receptor gp130 / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism; D053680:Leukemia Inhibitory Factor Receptor alpha Subunit / Q000235:genetics / Q000378:metabolism*; D020125:Mutation, Missense; D010766:Phosphorylation; D020801:Receptor, Ciliary Neurotrophic Factor / Q000235:genetics / Q000378:metabolism*; D019947:Receptors, Interleukin-6 / Q000235:genetics / Q000378:metabolism*; D050796:STAT3 Transcription Factor / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D020934:Ciliary Neurotrophic Factor; D015850:Interleukin-6; C507840:LIFR protein, human; D053680:Leukemia Inhibitory Factor Receptor alpha Subunit; D020801:Receptor, Ciliary Neurotrophic Factor; D019947:Receptors, Interleukin-6; D050796:STAT3 Transcription Factor; D050822:Cytokine Receptor gp130
keywords: Cell Surface Receptor; Cytokine Action; Interleukin; Receptor Structure-Function; Signal Transduction