TABLE 6.

Astrocyte function in Rett syndrome and Fragile X syndrome.

Source	Region/Sample	Experiment	Findings	References
Mecp2–/y	Hippocampal neurons (P1), cortical astrocytes (P1–P2)	Astrocyte/neuron co-culture, immune-cytochemistry	Mecp2–/y astrocytes negatively influence dendrite arborization	Ballas et al., 2009
Mecp2Stop/y	Hippocampal neurons (3 months +)	Immunohistochemistry, behavioral assessment	Re-expression of Mecp2 rescues dendrite morphology, locomotor and respiratory phenotypes	Lioy et al., 2011
Mecp2tm1.1Bird	Primary astrocyte cultures (P1) from cerebral cortex	Expression microarray, ChIP-seq	Astrocytes express a unique gene profile incl. synaptic genes	Yasui et al., 2013
Fmr1 –/y	Hippocampal neurons, Primary astrocyte cultures (P0-P1)	Astrocyte/neuron co-culture, immune-cytochemistry	Fmr1 astrocytes-neuron co-cultures results in abnormal increased dendritic protrusions	Jacobs and Doering, 2010
Fmr1 –/y	Conditional knockout and conditional restored astrocytes (P24–P30, P38–P45), cortical slices	Behavioral assessment, Whole cell patch clamp	Loss of FMRP: ↑Cortical activity, ↑Locomotor activity, ↓Social novelty preference and memory acquisition deficits; Corrected by Fmr1 reactivation	Jin et al., 2021
Fmr1 –/y	iPSC from patients with FXS differentiated into astrocytes	RNA sequencing, immunocytochemistry.	↑uPA expression that alters neuronal phosphorylation of TrkB	Peteri et al., 2021

Main findings of studies reporting on astrocyte function and morphology in Rett syndrome and Fragile X syndrome. Abbreviations: Mecp2, methyl-CpG binding protein 2 gene; Fmr1, fragile X mental retardation 1 gene, FRMP, fragile X mental retardation protein; iPSC, induced pluripotent stem cell; FXS, Fragile X syndrome; uPA, urokinase plasminogen activator; TrkB tropomycin receptor kinase B.