title: Selective activation of metabotropic glutamate receptor 7 induces inhibition of cellular proliferation and promotes astrocyte differentiation of ventral mesencephalon human neural stem/progenitor cells.
abstract: Expression of group III metabotropic glutamate receptors (mGluR) was established by RT-PCR and immunocytochemistry on a cultured clonal human neural stem/progenitor cell (hNSPC) line derived from fetal ventral mesencephalon (VM). Selective activation of these receptors by the group III mGluR agonist L-(+)-2-amino-4-phosphonobutyric acid (L-AP4) prevented increases in cAMP levels following forskolin stimulation, suggesting these receptors are coupled to their canonical G-protein coupled signal transduction pathway. Tonic exposure of undifferentiated cultures to L-AP4 resulted in a decrease in cellular metabolism and proliferation in the absence of toxicity, as measured by MTT and LDH assays, in a dose-dependent manner. This was confirmed by a reduction in BrdU incorporation into nuclear DNA, suggestive of an anti-proliferative effect of L-AP4. This effect was rescued by co-addition of the broad-spectrum group III mGluR competitive antagonist (RS)-a-cyclopropyl-4-phosphonophenylglycine (CPPG), demonstrating a receptor-mediated mechanism, but not mimicked by application of the cell permeable cAMP analogue dibutyrl cAMP (db-cAMP). The potency of these effects of L-AP4 indicates that this is an mGlu7 subtype-mediated effect. Tonic exposure of undifferentiated cultures to the mGlu7 selective allosteric agonist N,N'-bis(diphenylmethyl)-1,2-ethanediamine dihydrochloride (AMN082), but not the mGlu4 selective allosteric agonist (±)-cis-2-(3,5-dicholorphenylcarbamoyl)cyclohexanecarboxylic acid (VU0155041), or the mGlu8 selective agonist (S)-3,4-dicarboxyphenylglycine ((S)-3,4-DCPG) resulted in an identical anti-proliferative effect to L-AP4, confirming the involvement of the mGlu7 subtype. In differentiating cultures, tonic exposure to L-AP4 or AMN082 resulted in a significant shift towards an astrocyte cell fate. The mGlu7 receptor therefore provides a new opportunity to influence the proliferation and differentiation of ventral mesencephalon-derived hNSPC.
authors.affiliation: Kings College London, Department of Neuroscience, Centre for the Cellular Basis of Behaviour, The James Black Centre, London, UK. anthony.vernon@kcl.ac.uk
authors.forename: Anthony C
authors.initials: AC
authors.lastname: Vernon
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Smith
authors.forename: Lara
authors.initials: L
authors.lastname: Stevanato
authors.forename: Michel
authors.initials: M
authors.lastname: Modo
mesh_terms: D001253:Astrocytes / Q000166:cytology / Q000187:drug effects*; D001483:Base Sequence; D002454:Cell Differentiation / Q000187:drug effects*; D049109:Cell Proliferation; D017931:DNA Primers; D006801:Humans; D007150:Immunohistochemistry; D008636:Mesencephalon / Q000166:cytology / Q000187:drug effects*; D016133:Polymerase Chain Reaction; D018094:Receptors, Metabotropic Glutamate / Q000819:agonists*; D013234:Stem Cells / Q000166:cytology*
chemical_list: D017931:DNA Primers; D018094:Receptors, Metabotropic Glutamate; C102719:metabotropic glutamate receptor 7