title: Modulation of RhoGTPases improves the behavioral phenotype and reverses astrocytic deficits in a mouse model of Rett syndrome.
abstract: RhoGTPases are crucial molecules in neuronal plasticity and cognition, as confirmed by their role in non-syndromic mental retardation. Activation of brain RhoGTPases by the bacterial cytotoxic necrotizing factor 1 (CNF1) reshapes the actin cytoskeleton and enhances neurotransmission and synaptic plasticity in mouse brains. We evaluated the effects of a single CNF1 intracerebroventricular inoculation in a mouse model of Rett syndrome (RTT), a rare neurodevelopmental disorder and a genetic cause of mental retardation, for which no effective therapy is available. Fully symptomatic MeCP2-308 male mice were evaluated in a battery of tests specifically tailored to detect RTT-related impairments. At the end of behavioral testing, brain sections were immunohistochemically characterized. Magnetic resonance imaging and spectroscopy (MRS) were also applied to assess morphological and metabolic brain changes. The CNF1 administration markedly improved the behavioral phenotype of MeCP2-308 mice. CNF1 also dramatically reversed the evident signs of atrophy in astrocytes of mutant mice and restored wt-like levels of this cell population. A partial rescue of the overexpression of IL-6 cytokine was also observed in RTT brains. CNF1-induced brain metabolic changes detected by MRS analysis involved markers of glial integrity and bioenergetics, and point to improved mitochondria functionality in CNF1-treated mice. These results clearly indicate that modulation of brain RhoGTPases by CNF1 may constitute a totally innovative therapeutic approach for RTT and, possibly, for other disorders associated with mental retardation.
authors.affiliation: Department Cell Biology and Neuroscience, Istituto Superiore di Sanità, Roma, Italy.
authors.forename: Bianca
authors.initials: B
authors.lastname: De Filippis
authors.forename: Alessia
authors.initials: A
authors.lastname: Fabbri
authors.forename: Daiana
authors.initials: D
authors.lastname: Simone
authors.forename: Rossella
authors.initials: R
authors.lastname: Canese
authors.forename: Laura
authors.initials: L
authors.lastname: Ricceri
authors.forename: Fiorella
authors.initials: F
authors.lastname: Malchiodi-Albedi
authors.forename: Giovanni
authors.initials: G
authors.lastname: Laviola
authors.forename: Carla
authors.initials: C
authors.lastname: Fiorentini
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000502:physiology*; D001427:Bacterial Toxins / Q000627:therapeutic use; D001921:Brain / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D003072:Cognition Disorders / Q000188:drug therapy / Q000209:etiology; D003213:Conditioning, Psychological / Q000187:drug effects; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D029968:Escherichia coli Proteins / Q000627:therapeutic use; D005106:Exploratory Behavior / Q000187:drug effects; D005239:Fear / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D007276:Injections, Intraventricular; D015850:Interleukin-6 / Q000378:metabolism; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D051783:Methyl-CpG-Binding Protein 2 / Q000235:genetics; D051379:Mice; D009048:Motor Skills / Q000187:drug effects / Q000502:physiology; D010641:Phenotype; D015518:Rett Syndrome / Q000188:drug therapy / Q000201:enzymology* / Q000235:genetics / Q000473:pathology*; D020741:rho GTP-Binding Proteins / Q000378:metabolism*
chemical_list: D001427:Bacterial Toxins; D029968:Escherichia coli Proteins; D005904:Glial Fibrillary Acidic Protein; D015850:Interleukin-6; C497393:Mecp2 protein, mouse; D051783:Methyl-CpG-Binding Protein 2; C060296:cytotoxic necrotizing factor type 1; D020741:rho GTP-Binding Proteins