Project description:Autism spectrum disorder (ASD) is characterized by a complex etiology, with genetic determinants significantly influencing its manifestation. Among these, the Scn2a gene emerges as a pivotal player, crucially involved in oligodendrocyte (OL) function. The present study elucidates the underexplored roles of Scn2a in OL functionality, subsequently affecting myelination and auditory neural processes. The results reveal a nuanced interplay between OLs and axons, where Scn2a deletion causes alterations in OL differentiation and myelination. This disruption, in turn, instigates changes in axonal properties and neuronal activities at the single cell level. Furthermore, OL-specific Scn2a deletion compromises the integrity of neural circuitry within auditory pathways, leading to auditory hypersensitivity—a common sensory abnormality observed in ASD. Through transcriptional profiling, we identified alterations in the expression of myelin-associated genes, highlighting the cellular consequences engendered by Scn2a deletion. In summary, the findings of this study provide unprecedented insights into the pathway from Scn2a deletion in OL to sensory abnormalities in ASD, underscoring the integral role of Scn2a-mediated OL myelination in auditory responses. This research thereby provides novel insights into the intricate tapestry of genetic and cellular interactions inherent in ASD.
Project description:Myelinating glia in the auditory system enclose auditory nerve fibers, providing an insulating effect that facilitates rapid transfer of auditory information from the ear to the brain. Here we show that noise exposure at the levels sufficient for inducing hearing loss cause a rapid cellular and molecular response on myelinating glia that precedes neuron degeneration. The response is characterized by inflammatory response, myelin dysmorphology and widespread changes in myelin-related gene expression. Another characteristic was change in expression of the quaking gene (QKI), which encodes a group of RNA binding proteins that are enriched in myelinating glia. Changes in QKI were accompanied by changes in numerous known and potential QKI target genes, including many genes associated with myelination. Our results implicate QKI as a critical early component in the noise response, influencing glia dysfunction that leads to auditory nerve demyelination and, ultimately, sensorineural hearing loss.
Project description:Myelination depends on maintenance of oligodendrocytes that arise from oligodendrocyte precursor cells (OPCs). We show that OPC-specific proliferation, morphology, and BMAL1 are time-of-day dependent. Knock out of Bmal1 in OPCs during development disrupts expression of genes associated with circadian rhythms, proliferation, density, morphology, and migration, leading to changes in OPC dynamics in a spatio-temporal manner. Furthermore, these deficits translate into thinner myelin, dysregulated cognitive and motor function, and increased sleep fragmentation. OPC-specificBmal1loss in adulthood does not alter OPC density at baseline but impairs remyelination of a demyelinated lesion driven by changes in OPC morphology and migration. Lastly, we show sleep fragmentation is associated with increased prevalence of the demyelinating disorder multiple sclerosis (MS), suggesting a link between MS and sleep that requires further investigation. These findings have broad mechanistic and therapeutic implications for brain disorders that include both myelin and sleep phenotypes.
Project description:Oligodendrocyte (OL) differentiation and myelin development are complex events regulated by numerous signal transduction factors. Here, we report that phosphoinositide-3 kinase enhancer L (PIKE-L) is required for OL development and myelination. PIKE-L expression is up-regulated when oligodendrocyte progenitor cells commit to differentiation. Conversely, depleting phosphoinositide-3 kinase enhancer (PIKE) expression by shRNA prevents oligodendrocyte progenitor cell differentiation. In both conventional PIKE knockout (PIKE(-/-)) and OL-specific PIKE knockout mice, the number of OLs is reduced in the corpus callosum. PIKE(-/-) OLs also display defects when forming myelin sheath on neuronal axons during neonatal development, which is partially rescued when PTEN is ablated. In addition, Akt/mTOR signaling is impaired in OL-enriched tissues of the PIKE(-/-) mutant, leading to reduced expression of critical proteins for myelin development and hypomyelination. Moreover, myelin repair of lysolecithin-induced lesions is delayed in PIKE(-/-) brain. Thus, PIKE plays pivotal roles to advance OL development and myelinogenesis through Akt/mTOR activation.
Project description:We characterized the proteome of the auditory brainstem of a chick embryo on embryonic day 13, when apoptosis occurs in auditory nuclei. We identified caspase substrates by searching the peptidome for peptides C-terminal to caspase-typical cleavage sites.
Project description:Caenorhabditis elegans asd-2, RNA-binding protein asd-2 [Source:UniProtKB/Swiss-Prot;Acc:G5EFF1], is differentially expressed in 2 experiment(s);
Project description:Caenorhabditis elegans asd-2, RNA-binding protein asd-2 [Source:UniProtKB/Swiss-Prot;Acc:G5EFF1], is expressed in 1 baseline experiment(s);