The neuroprotective effects of orthosteric agonists of group II and III mGluRs in primary neuronal cell cultures are dependent on developmental stage.
Activation of metabotropic glutamate receptors (mGluRs) modulates neuronal excitability. Here, we evaluated the neuroprotective potential of four structurally diverse activators of group II and III mGluRs: an orthosteric agonist of group II (LY354740), an orthosteric agonist of group III (ACPT-I), an allosteric agonist of mGluR7 (AMN082) and a positive allosteric modulator (PAM) of mGluR4 (VU0361737). Neurotoxicity was induced by the pro-apoptotic agents: staurosporine (St) and doxorubicin (Dox) or the excitotoxic factor glutamate (Glu). The effects were analyzed in primary hippocampal (HIP) and cerebellar granule cell (CGC) cultures at two developmental stages, at 7 and 12 days in vitro (DIV). The data reveal a general neuroprotective effect of group II and III mGluR activators against the St- and Glu- but not Dox-induced cell damage. We found that neuroprotective effects of group II and III mGluR orthosteric agonists (LY354740 and ACPT-I) were higher at 12 DIV when compared to 7 DIV cells. In contrast, the efficiency of allosteric mGluR agents (AMN082 and VU0361737) did not differ between 7 and 12 DIV in both, St and Glu models of neuronal cell damage. Interestingly, the protective effects of activators of group II and III mGluRs were blocked by relevant antagonists only against Glu-induced neurotoxicity. Moreover, the observed neuroprotective action of group II and III mGluR activators in the St model was associated with a decreased number of PI-positive cells and no alterations in the caspase-3 activity. Finally, we showed that MAPK/ERK pathway activation was potentially involved in the mechanism of ACPT-I- and AMN082-induced neuroprotection against the St-evoked cellular damage. Our comparative study demonstrated the developmental stage-dependent neuroprotective effect of orthosteric group II and III mGluR agonists. In comparison to allosteric modulators, orthosteric compounds may provide more specific tools for suppression of neuronal cell loss associated with various chronic neurodegenerative conditions. Our results also suggest that the inhibition of intracellular pathways mediating necrotic, rather than apoptotic cascades, may be involved in neuroprotective effects of activators of group II and III mGluRs.
Department of Experimental Neuroendocrinology, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12 Street, PL 31-343 Kraków, Poland. Electronic address: jantas@if-pan.krakow.pl.
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Jantas
Department of Experimental Neuroendocrinology, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12 Street, PL 31-343 Kraków, Poland.
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Gręda
Department of Molecular Neuropharmacology, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12 Street, PL 31-343 Kraków, Poland.
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Gołda
Department of Molecular Neuropharmacology, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12 Street, PL 31-343 Kraków, Poland.
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Korostyński
Department of Experimental Neuroendocrinology, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12 Street, PL 31-343 Kraków, Poland.
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Lasoń
D000814:Aniline Compounds / Q000008:administration & dosage*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001559:Benzhydryl Compounds / Q000008:administration & dosage*; D001643:Bridged Bicyclo Compounds / Q000008:administration & dosage*; D016923:Cell Death / Q000187:drug effects*; D002478:Cells, Cultured; D002531:Cerebellum / Q000187:drug effects; D003517:Cyclopentanes / Q000008:administration & dosage*; D004317:Doxorubicin / Q000633:toxicity; D018698:Glutamic Acid / Q000633:toxicity; D006624:Hippocampus / Q000187:drug effects; D051379:Mice; D009474:Neurons / Q000187:drug effects*; D018696:Neuroprotective Agents / Q000008:administration & dosage*; D010848:Picolinic Acids / Q000008:administration & dosage*; D061251:Primary Cell Culture; D018094:Receptors, Metabotropic Glutamate / Q000819:agonists*; D019311:Staurosporine / Q000633:toxicity; D014233:Tricarboxylic Acids / Q000008:administration & dosage*
C409063:1-aminocyclopentane-1,2,4-tricarboxylic acid; D000814:Aniline Compounds; D001559:Benzhydryl Compounds; D001643:Bridged Bicyclo Compounds; D003517:Cyclopentanes; C507346:N,N'-dibenzhydrylethane-1,2-diamine dihydrochloride; C587536:N-(4-chloro-3-methoxyphenyl)-2-picolinamide; D018696:Neuroprotective Agents; D010848:Picolinic Acids; D018094:Receptors, Metabotropic Glutamate; D014233:Tricarboxylic Acids; C102719:metabotropic glutamate receptor 7; D018698:Glutamic Acid; D004317:Doxorubicin; D019311:Staurosporine; C104753:eglumetad; C108823:metabotropic glutamate receptor 4
ACPT-I; AMN082; Doxorubicin; Glutamate; LY354740; Primary neuronal cell cultures; Staurosporine; VU0361737