Genetic Downregulation of the Metabotropic Glutamate Receptor Type 5 Dampens the Reactive and Neurotoxic Phenotype of Adult ALS Astrocytes
Carola Torazza,
Francesca Provenzano,
Elena Gallia,
Maria Cerminara,
Matilde Balbi,
Tiziana Bonifacino,
Sara Tessitore,
Silvia Ravera,
Cesare Usai,
Ilaria Musante,
Aldamaria Puliti,
Ludo Van Den Bosch,
Paymaan Jafar-nejad,
Frank Rigo,
Marco Milanese,
Giambattista Bonanno
Affiliations
Carola Torazza
Department of Pharmacy (DIFAR), University of Genoa, Viale Cembrano 4, 16148 Genova, Italy
Francesca Provenzano
Department of Pharmacy (DIFAR), University of Genoa, Viale Cembrano 4, 16148 Genova, Italy
Elena Gallia
Department of Pharmacy (DIFAR), University of Genoa, Viale Cembrano 4, 16148 Genova, Italy
Maria Cerminara
Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genoa, Largo Paolo Daneo, 16132 Genoa, Italy
Matilde Balbi
Department of Pharmacy (DIFAR), University of Genoa, Viale Cembrano 4, 16148 Genova, Italy
Tiziana Bonifacino
Department of Pharmacy (DIFAR), University of Genoa, Viale Cembrano 4, 16148 Genova, Italy
Sara Tessitore
Department of Pharmacy (DIFAR), University of Genoa, Viale Cembrano 4, 16148 Genova, Italy
Silvia Ravera
Department of Experimental Medicine (DIMES), University of Genoa, Via Alberti L.B. 2, 16132 Genova, Italy
Cesare Usai
Institute of Biophysics, National Research Council (CNR), Via De Marini 6, 16149 Genoa, Italy
Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genoa, Largo Paolo Daneo, 16132 Genoa, Italy
Ludo Van Den Bosch
Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute, KU Leuven-University of Leuven, 3000 Leuven, Belgium
Paymaan Jafar-nejad
Ionis Pharmaceuticals, Carlsbad, CA 92010, USA
Frank Rigo
Ionis Pharmaceuticals, Carlsbad, CA 92010, USA
Marco Milanese
Department of Pharmacy (DIFAR), University of Genoa, Viale Cembrano 4, 16148 Genova, Italy
Giambattista Bonanno
Department of Pharmacy (DIFAR), University of Genoa, Viale Cembrano 4, 16148 Genova, Italy
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by progressive degeneration of motor neurons (MNs). Astrocytes display a toxic phenotype in ALS, which results in MN damage. Glutamate (Glu)-mediated excitotoxicity and group I metabotropic glutamate receptors (mGluRs) play a pathological role in the disease progression. We previously demonstrated that in vivo genetic ablation or pharmacological modulation of mGluR5 reduced astrocyte activation and MN death, prolonged survival and ameliorated the clinical progression in the SOD1G93A mouse model of ALS. This study aimed to investigate in vitro the effects of mGluR5 downregulation on the reactive spinal cord astrocytes cultured from adult late symptomatic SOD1G93A mice. We observed that mGluR5 downregulation in SOD1G93A astrocytes diminished the cytosolic Ca2+ overload under resting conditions and after mGluR5 simulation and reduced the expression of the reactive glial markers GFAP, S100β and vimentin. In vitro exposure to an anti-mGluR5 antisense oligonucleotide or to the negative allosteric modulator CTEP also ameliorated the altered reactive astrocyte phenotype. Downregulating mGluR5 in SOD1G93A mice reduced the synthesis and release of the pro-inflammatory cytokines IL-1β, IL-6 and TNF-α and ameliorated the cellular bioenergetic profile by improving the diminished oxygen consumption and ATP synthesis and by lowering the excessive lactate dehydrogenase activity. Most relevantly, mGluR5 downregulation hampered the neurotoxicity of SOD1G93A astrocytes co-cultured with spinal cord MNs. We conclude that selective reduction in mGluR5 expression in SOD1G93A astrocytes positively modulates the astrocyte reactive phenotype and neurotoxicity towards MNs, further supporting mGluR5 as a promising therapeutic target in ALS.
