Open Access

ARTICLE

Expression of biologically active mouse ciliary neutrophic factor (CNTF) and soluble CNTFRα in Escherichia coli and characterization of their functional specificities

Isabelle Cognet¹, Florence Guilhot¹, Sylvie Chevalier², Angélique Guay-Giroux¹, Alexandra Bert¹, Greg C. A. Elson³, Hugues Gascan², Jean-François Gauchat¹

1 Département de pharmacologie, Université de Montréal, Montreal, Canada
2 INSERM U564, CHU Angers, 4, rue Larrey, 49033 Angers, France
3 NovImmune SA, Geneva, Switzerland

* Corresponding Author: Jean-François Gauchat,

European Cytokine Network 2004, 15(3), 255-262.

Accepted 17 May 2004;

Abstract

Ciliary neurotrophic factor (CNTF) is a neuroprotective cytokine initially identified in chick embryo. It has been evaluated for the treatment of neurodegenerative diseases. CNTF also acts on non-neuronal cells such as oligodendrocytes, astrocytes, adipocytes and skeletal muscles cells. CNTF has regulatory effects on body weight and is currently in clinical trial for the treatment of diabetes and obesity. CNTF mediates its function by activating a tripartite receptor comprising the CNTF receptor α chain (CNTFRα), the leukemia inhibitory factor receptor β chain (LIFRβ) and gp130. Human, rat and chicken CNTF have been expressed as recombinant proteins, and most preclinical studies in murine models have been performed using rat recombinant protein. Rat and human CNTF differ in their fine specificities: in addition to CNTFR, rat CNTF has been shown to activate the LIFR (a heterodimer of LIFRβ and gp130), whereas human CNTF can bind and activate a tripartite receptor comprising the IL-6 receptor α chain (IL-6Rα) and LIFR. To generate tools designed for mouse models of human diseases; we cloned and expressed in E. coli both mouse CNTF and the CNTFRα chain. Recombinant mouse CNTF was active and showed a high level of specificity for mouse CNTFR. It shares the arginine residue with rat CNTF which prevents binding to IL-6Rα. It did not activate the LIFR at all concentrations tested. Recombinant mouse CNTF is therefore specific for CNTFR and as such represents a useful tool with which to study CNTF in mouse models. It appears well suited for the comparative evaluation of CNTF and the two additional recently discovered CNTFR ligands, cardiotrophin-like cytokine/cytokine-like factor-1 and neuropoietin.

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