title: Imbalance of excitatory/inhibitory synaptic protein expression in iPSC-derived neurons from FOXG1(+/-) patients and in foxg1(+/-) mice.
abstract: Rett syndrome (RTT) is a severe neurodevelopmental disorder associated with mutations in either MECP2, CDKL5 or FOXG1. The precise molecular mechanisms that lead to the pathogenesis of RTT have yet to be elucidated. We recently reported that expression of GluD1 (orphan glutamate receptor δ-1 subunit) is increased in iPSC-derived neurons obtained from patients with mutations in either MECP2 or CDKL5. GluD1 controls synaptic differentiation and shifts the balance between excitatory and inhibitory synapses toward the latter. Thus, an increase in GluD1 might be a critical factor in the etiology of RTT by affecting the excitatory/inhibitory balance in the developing brain. To test this hypothesis, we generated iPSC-derived neurons from FOXG1(+/-) patients. We analyzed mRNA and protein levels of GluD1 together with key markers of excitatory and inhibitory synapses in these iPSC-derived neurons and in Foxg1(+/-) mouse fetal (E11.5) and adult (P70) brains. We found strong correlation between iPSC-derived neurons and fetal mouse brains, where GluD1 and inhibitory synaptic markers (GAD67 and GABA AR-α1) were increased, whereas the levels of a number of excitatory synaptic markers (VGLUT1, GluA1, GluN1 and PSD-95) were decreased. In adult mice, GluD1 was decreased along with all GABAergic and glutamatergic markers. Our findings further the understanding of the etiology of RTT by introducing a new pathological event occurring in the brain of FOXG1(+/-) patients during embryonic development and its time-dependent shift toward a general decrease in brain synapses.
authors.affiliation: Medical Genetics, University of Siena, Siena, Italy.|Department of Pharmacology, University of California, Davis, Davis, CA, USA.
authors.forename: Tommaso
authors.initials: T
authors.lastname: Patriarchi
authors.affiliation: Medical Genetics, University of Siena, Siena, Italy.
authors.forename: Sonia
authors.initials: S
authors.lastname: Amabile
authors.affiliation: Genetica Medica, Azienda Ospedaliera Universitaria Senese, Siena, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Frullanti
authors.affiliation: Medical Genetics, University of Siena, Siena, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Landucci
authors.affiliation: Medical Genetics, University of Siena, Siena, Italy.
authors.forename: Caterina
authors.initials: C
authors.lastname: Lo Rizzo
authors.affiliation: Medical Genetics, University of Siena, Siena, Italy.|Genetica Medica, Azienda Ospedaliera Universitaria Senese, Siena, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Ariani
authors.affiliation: Institute of Neuroscience, Italian National Research Council, Pisa, Italy.|Scuola Normale Superiore, Pisa, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Costa
authors.affiliation: Institute of Neuroscience, Italian National Research Council, Pisa, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Olimpico
authors.affiliation: Department of Pharmacology, University of California, Davis, Davis, CA, USA.
authors.forename: Johannes
authors.initials: J
authors.lastname: W Hell
authors.affiliation: Child Study Center, Yale University School of Medicine, New Haven, CT, USA.|Department of Neurobiology, Yale University School of Medicine, New Haven, CT, USA.
authors.forename: Flora
authors.initials: F
authors.lastname: M Vaccarino
authors.affiliation: Medical Genetics, University of Siena, Siena, Italy.|Genetica Medica, Azienda Ospedaliera Universitaria Senese, Siena, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Renieri
authors.affiliation: Medical Genetics, University of Siena, Siena, Italy.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Meloni
mesh_terms: D000293:Adolescent; D000818:Animals; D001921:Brain / Q000254:growth & development / Q000378:metabolism; D002478:Cells, Cultured; D005260:Female; D051858:Forkhead Transcription Factors / Q000235:genetics*; D005969:Glutamate Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000166:cytology / Q000378:metabolism; D007223:Infant; D051379:Mice; D008810:Mice, Inbred C57BL; D009419:Nerve Tissue Proteins / Q000235:genetics*; D055495:Neurogenesis; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D017470:Receptors, Glutamate / Q000235:genetics / Q000378:metabolism*; D015518:Rett Syndrome / Q000235:genetics / Q000378:metabolism*; D013569:Synapses / Q000378:metabolism
chemical_list: C090173:FOXG1 protein, human; D051858:Forkhead Transcription Factors; C489565:Foxg1 protein, mouse; D009419:Nerve Tissue Proteins; D017470:Receptors, Glutamate; C570817:GluD1 protein, mouse; D005969:Glutamate Dehydrogenase; C561840:GLUD1 protein, human