Project description:Analysis of astrocyte gene expression after induction of plasticty in the mouse visual cortex, spanning the time of synapse maturation to adulthood.
Project description:Analysis of astrocyte gene expression across postnatal development in the mouse visual cortex, spanning the time of synaptogenesis and synapse maturation.
Project description:Visual deprivation, either in the form of dark rearing (DR) or monocular deprivation (MD) are established paradigms for studying cortical plasticity. We have used miRNA microarray to uncover miRNAs whose expression is altered in primary visual cortex following DR and/or MD.
Project description:Visual deprivation, either in the form of dark rearing (DR) or monocular deprivation (MD) are established paradigms for studying cortical plasticity. We have used miRNA microarray to uncover miRNAs whose expression is altered in primary visual cortex following DR and/or MD. C57BL6 mice were reared in normal light and dark conditions (control) till P28, in complete darkness since birth (DR) till P28, or were grown in normal light/dark conditions from birth till P24 and then subjected to lid suturing of one eye till P28. Mice were euthanized at P28 and their primary visual cortex areas were excised and subjected to RNA isolation. In the case of MD mice only the contralateral to lid suture primary visual cortex was extracted. 100ng of total RNA (tested and quantified using the Agilent Bioanalyzer 2100) were labeled using the Agilent miRNA labeling system and hybridized to Agilent murine miRNA arrays. Microarrays were hybridized overnight at 64 ºC, scanned using an Agilent scanner and extracted with Agilent feature extractor 10.1.
Project description:Visual cortical circuits show profound plasticity during early life and are later stabilized by molecular "brakes" limiting excessive circuit rewiring beyond a critical period. How the appearance of these factors is coordinated during the transition from development to adulthood remains unknown. We analyzed the role of miR-29a, a miRNA targeting factors involved in several important pathways for plasticity such as extracellular matrix and chromatin regulation. We found that visual cortical miR-29a expression in the visual cortex dramatically increases with age, but it is not experience-dependent. Precocious high levels of miR-29a induced by targeted intracortical injections of a miR-29a mimic blocked ocular dominance plasticity and caused an early appearance of perineuronal nets. Conversely, inhibition of miR-29a in adult mice using LNA antagomirs activated ocular dominance plasticity, reduced perineuronal net intensity and number, and changed their chemical composition restoring permissive low chondroitin 4-O-sulfation levels characteristic of juvenile mice. Activated adult plasticity had the typical functional and proteomic signature of juvenile plasticity. Transcriptomic and proteomic studies indicated that miR-29a manipulation regulates the expression of plasticity factors acting at different cellular levels, from chromatin regulation to synaptic organization and extracellular matrix remodeling. Intriguingly, the projection of miR-29a regulated gene dataset onto cell-specific transcriptomes revealed that parvalbumin-positive interneurons and oligodendrocytes were the most affected cells. Overall, miR29a is a master regulator of the age-dependent plasticity brakes promoting stability of visual cortical circuits.
Project description:Visual cortical circuits show profound plasticity during early life and are later stabilized by molecular "brakes" limiting excessive circuit rewiring beyond a critical period. How the appearance of these factors is coordinated during the transition from development to adulthood remains unknown. We analyzed the role of miR-29a, a miRNA targeting factors involved in several important pathways for plasticity such as extracellular matrix and chromatin regulation. We found that visual cortical miR-29a expression in the visual cortex dramatically increases with age, but it is not experience-dependent. Precocious high levels of miR-29a induced by targeted intracortical injections of a miR-29a mimic blocked ocular dominance plasticity and caused an early appearance of perineuronal nets. Conversely, inhibition of miR-29a in adult mice using LNA antagomirs activated ocular dominance plasticity, reduced perineuronal net intensity and number, and changed their chemical composition restoring permissive low chondroitin 4-O-sulfation levels characteristic of juvenile mice. Activated adult plasticity had the typical functional and proteomic signature of juvenile plasticity. Transcriptomic and proteomic studies indicated that miR-29a manipulation regulates the expression of plasticity factors acting at different cellular levels, from chromatin regulation to synaptic organization and extracellular matrix remodeling. Intriguingly, the projection of miR-29a regulated gene dataset onto cell-specific transcriptomes revealed that parvalbumin-positive interneurons and oligodendrocytes were the most affected cells. Overall, miR29a is a master regulator of the age-dependent plasticity brakes promoting stability of visual cortical circuits.
Project description:Visual cortical circuits show profound plasticity during early life and are later stabilized by molecular "brakes" limiting excessive rewiring beyond a critical period. The mechanisms coordinating the expression of these factors during the transition from development to adulthood remain unknown. We found that miR-29a expression in the visual cortex dramatically increases with age, but it is not experience-dependent. Precocious high levels of miR-29a blocked ocular dominance plasticity and caused an early appearance of perineuronal nets. Conversely, inhibition of miR-29a in adult mice using LNA antagomirs activated ocular dominance plasticity, reduced perineuronal nets and restored their juvenile chemical composition. Activated adult plasticity had the typical functional and proteomic signature of critical period plasticity. Transcriptomic and proteomic studies indicated that miR-29a manipulation regulates the expression of plasticity brakes mainly affecting parvalbumin-positive interneurons. These data indicate that miR29a is a master regulator of the plasticity brakes promoting age-dependent stabilization of visual cortical circuits.
Project description:A better understanding of how Otx2 regulates plasticity in the visual cortex requires that its non-cell autonomous transcription targets be identified. We dissected layer IV of the visual cortex and used RNA-sequencing to analyze gene expression at postnatal day 30 (P30) and P100 in wild-type (WT) and Otx2+/GFP heterozygotes mice. The rationale is that CP plasticity is opened at P30 in WT but not in Otx2+/GFP mice, given that genetic deletion delays CP opening (Sugiyama et al., 2008), and that the CP is closed at P100 in WT mice and not yet in Otx2+/GFP mice. Thus, genes with similar expression at P30 in Otx2+/GFP and at P100 in WT mice but with a different level of expression during the critical period (P30 in WT or P100 Otx2+/GFP mice) were considered as potential genes involved in plasticity.
Project description:Chrdl1, a BMP antagonist, is an astrocyte-secreted factor that promotes synapse maturation in the upper layers of the visual cortex at P14. We analyzed the transcriptome of the visual cortex of WT and Chrdl1 KO mice at P14 in order to determine if genes related to BMP signaling, astrocyte development or synapse formation were altered.