title: Identification of a novel neurotrophic factor from primary retinal Müller cells using stable isotope labeling by amino acids in cell culture (SILAC).
abstract: Retinal Müller glial cells (RMGs) have a primary role in maintaining the homeostasis of the retina. In pathological situations, RMGs execute protective and regenerative effects, but they can also contribute to neurodegeneration. It has recently been recognized that cultured primary RMGs secrete pro-survival factors for retinal neurons for up to 2 weeks in culture, but this ability is lost when RMGs are cultivated for longer durations. In our study, we investigated RMG supernatants for novel neuroprotective factors using a quantitative proteomic approach. Stable isotope labeling by amino acids in cell culture (SILAC) was used on primary porcine RMGs. Supernatants of RMGs cultivated for 2 weeks were compared with supernatants from cells that had already lost their protective capacity. Using this approach, we detected established neurotrophic factors such as transferrin, osteopontin, and leukemia inhibitory factor and identified C-X-C motif chemokine 10 (CXCL10) as a novel candidate neuroprotective factor. All factors prolonged photoreceptor survival in vitro. Ex vivo treatment of retinal explants with leukemia inhibitory factor or CXCL10 demonstrated a neuroprotective effect on photoreceptors. Western blots on CXCL10- and leukemia inhibitory factor-stimulated explanted retina and photoreceptor lysates indicated activation of pro-survival signal transducer and activator of transcription signaling and B-cell lymphoma pathways. These findings suggest that CXCL10 contributes to the supportive potential of RMGs toward retinal neurons.
authors.affiliation: From the ‡Research Unit Protein Science, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany;
authors.forename: Christine
authors.initials: C
authors.lastname: von Toerne
authors.affiliation: From the ‡Research Unit Protein Science, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany;
authors.forename: Jacob
authors.initials: J
authors.lastname: Menzler
authors.affiliation: From the ‡Research Unit Protein Science, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany;
authors.forename: Alice
authors.initials: A
authors.lastname: Ly
authors.affiliation: From the ‡Research Unit Protein Science, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany;
authors.forename: Nicole
authors.initials: N
authors.lastname: Senninger
authors.affiliation: From the ‡Research Unit Protein Science, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany; §Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, 72076 Tübingen, Germany.
authors.forename: Marius
authors.initials: M
authors.lastname: Ueffing
authors.affiliation: From the ‡Research Unit Protein Science, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany; hauck@helmholtz-muenchen.de.
authors.forename: Stefanie M
authors.initials: SM
authors.lastname: Hauck
mesh_terms: D000596:Amino Acids; D000818:Animals; D002470:Cell Survival; D002478:Cells, Cultured; D054357:Chemokine CXCL10 / Q000378:metabolism*; D063928:Ependymoglial Cells / Q000378:metabolism*; D007553:Isotope Labeling; D009414:Nerve Growth Factors / Q000378:metabolism*; D020419:Photoreceptor Cells, Vertebrate; D013552:Swine
chemical_list: D000596:Amino Acids; D054357:Chemokine CXCL10; D009414:Nerve Growth Factors