Differential response of neuronal cells to a fusion protein of ciliary neurotrophic factor/soluble CNTF-receptor and leukemia inhibitory factor.
Ciliary neurotrophic factor (CNTF) displays neurotrophic activities on motor neurons and neural cell populations both in vivo and in vitro. On target cells lacking intrinsic expression of specific receptor alpha subunits cytokines of the IL-6 family only act in the presence of their specific agonistic soluble receptors. Here, we report the construction and expression of a CNTF/soluble CNTF-receptor (sCNTF-R) fusion protein (Hyper-CNTF) with enhanced biological activity on cells expressing gp130 and leukemia inhibitory factor receptor (LIF-R), but not membrane-bound CNTF-R. At the cDNA level, the C-terminus of the extracellular domain of human CNTF-R (amino acids 1-346) was linked via a single glycine residue to the N-terminus of human CNTF (amino acids 1-186). Recombinant Hyper-CNTF protein was expressed in COS-7 cells. Hyper-CNTF efficiently induced dose-dependent STAT3 phosphorylation and proliferation of BAF-3 cells stably transfected with gp130 and LIF-R cDNAs. While on BAF3/gp130/LIF-R cells, Hyper-CNTF and LIF exhibited similar biological responses, the activity of Hyper-CNTF on pheochromocytoma cells (PC12 cells) was quite distinct from that of LIF. In contrast to LIF, Hyper-CNTF stimulated neurite outgrowth of PC12 cells in a time- and dose-dependent manner correlating with the ability to phosphorylate MAP kinases. These data indicate that although LIF and Hyper-CNTF use the same heterodimeric receptor complex of gp130 and LIFR, only Hyper-CNTF induces neuronal differentiation. The therapeutic potential of Hyper-CNTF as a superagonistic neurotrophin is discussed.
März
Pia
P
Department of Physiology, University of Basel, Switzerland. p.maerz@unibas.ch
Ozbek
Suat
S
Fischer
Martina
M
Voltz
Nicole
N
Otten
Uwe
U
Rose-John
Stefan
S
D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D019556:COS Cells; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002522:Chlorocebus aethiops; D020934:Ciliary Neurotrophic Factor / Q000235:genetics / Q000494:pharmacology*; D050822:Cytokine Receptor gp130; D004268:DNA-Binding Proteins / Q000378:metabolism*; D053680:Leukemia Inhibitory Factor Receptor alpha Subunit; D008562:Membrane Glycoproteins / Q000378:metabolism*; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D016716:PC12 Cells / Q000187:drug effects / Q000378:metabolism; D021122:Protein Subunits; D051381:Rats; D020801:Receptor, Ciliary Neurotrophic Factor / Q000235:genetics / Q000378:metabolism*; D018121:Receptors, Cytokine / Q000378:metabolism*; D053606:Receptors, OSM-LIF; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000494:pharmacology; D050796:STAT3 Transcription Factor; D015534:Trans-Activators / Q000378:metabolism*; D014162:Transfection; D014407:Tumor Cells, Cultured
D015703:Antigens, CD; D020934:Ciliary Neurotrophic Factor; D004268:DNA-Binding Proteins; C494200:Il6st protein, mouse; C494201:Il6st protein, rat; C507840:LIFR protein, human; D053680:Leukemia Inhibitory Factor Receptor alpha Subunit; C507841:Lifr protein, mouse; C507842:Lifr protein, rat; D008562:Membrane Glycoproteins; D021122:Protein Subunits; D020801:Receptor, Ciliary Neurotrophic Factor; D018121:Receptors, Cytokine; D053606:Receptors, OSM-LIF; D011993:Recombinant Fusion Proteins; D050796:STAT3 Transcription Factor; C494087:Stat3 protein, mouse; C494088:Stat3 protein, rat; D015534:Trans-Activators; D050822:Cytokine Receptor gp130; D020928:Mitogen-Activated Protein Kinases