Global Impairment of Immediate-Early Genes Expression in Rett Syndrome Models and Patients Linked to Myelination Defects

• Published in: International journal of molecular sciences 2023-01, Vol.24 (2), p.1453
• Main Authors: Petazzi, Paolo, Jorge-Torres, Olga Caridad, Gomez, Antonio, Scognamiglio, Iolanda, Serra-Musach, Jordi, Merkel, Angelika, Grases, Daniela, Xiol, Clara, O'Callaghan, Mar, Armstrong, Judith, Esteller, Manel, Guil, Sonia
• Format: Article
• Language: English
• Subjects: Animals; Brain; Brain - metabolism; Chromatin; Cognitive ability; Disease Models, Animal; EGR2; Gene expression; Genes; Genes, Immediate-Early; Hippocampus - metabolism; IEGs; Immediate-early proteins; Kinases; Mammals - metabolism; MeCP2; MeCP2 protein; Memory; Methyl-CpG binding protein; Methyl-CpG-Binding Protein 2 - metabolism; Mice; Mutation; Myelination; Neurodevelopmental disorders; Neurons - metabolism; Peripheral blood; Prefrontal cortex; Proteins; Rett syndrome; Rett Syndrome - genetics; Rett Syndrome - metabolism; Sequence analysis; Synaptic plasticity; Synaptogenesis; Transcription factors
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms24021453

Rett syndrome (RTT) is a severe neurodevelopmental disease caused almost exclusively by mutations to the gene. This disease may be regarded as a synaptopathy, with impairments affecting synaptic plasticity, inhibitory and excitatory transmission and network excitability. The complete understanding of the mechanisms behind how the transcription factor MeCP2 so profoundly affects the mammalian brain are yet to be determined. What is known, is that MeCP2 involvement in activity-dependent expression programs is a critical link between this protein and proper neuronal activity, which allows the correct maturation of connections in the brain. By using RNA-sequencing analysis, we found several immediate-early genes (IEGs, key mediators of activity-dependent responses) directly bound by MeCP2 at the chromatin level and upregulated in the hippocampus and prefrontal cortex of the -KO mouse. Quantification of the IEGs response to stimulus both in vivo and in vitro detected an aberrant expression pattern in MeCP2-deficient neurons. Furthermore, altered IEGs levels were found in RTT patient's peripheral blood and brain regions of post-mortem samples, correlating with impaired expression of downstream myelination-related genes. Altogether, these data indicate that proper IEGs expression is crucial for correct synaptic development and that MeCP2 has a key role in the regulation of IEGs.