Project description:Multiple diseases are associated with a pathological hypoxia in the brain, resulting in various neurological sequalae. Understanding the response to hypoxia of neurons and neural stem cells (NSCs) will help devise better therapeutic strategies. We have exposed primary neurons (PN) and neural stem cells to 1% O2. Both cell types survived well, and neurons showed no obvious morphological changes. The NSCs, however, became fusiform, and displayed a population of cells with accelerated transition in cell cycle. Gene expression profile through microarray analysis revealed major differences in response to hypoxia between NSC and PN. Not only the number of genes significantly changes was ~five-fold higher in NSC, but the types of genes involved and the direction of change was quite different. In particular, NSCs up-regulated multiple growth factors and down-regulated most other cytokines and metalloproteases , while PN down-regulated most neuronal-specific genes, up-regulated growth factors, with no major effect on cytokines. We conclude that hypoxia 1- accelerates cell cycle transition of NSC in a post-transcriptional fashion ; 2-affects cytokines in NSC but not in neurons; 3-result in up-regulation of multiple growth factors in NSC and PN; and 4-suppresses neuronal specific functions. 1) Primary neurons (PN) and neural stem cells were exposed to 1% O2. 2) Gene expression profile through microarray analysis was used to determine the differences in response to hypoxia between NSC and PN.
Project description:Pontine nuclei (PN) neurons mediate the communication between the cerebral cortex and the cerebellum to refine skilled motor functions. Prior studies have shown that PN neurons fall into two subtypes based on their anatomic location and region-specific connectivity, but the extent of their heterogeneity and its molecular drivers remain unknown. Atoh1 encodes a transcription factor that is expressed in the PN precursors. We previously showed that partial loss-of-function of Atoh1 in mice results in delayed PN development and impaired motor learning. In this study, we performed single-cell RNA sequencing to elucidate the cell-state-specific functions of Atoh1 during PN development and discovered that Atoh1 regulates cell cycle exit, differentiation, migration, and survival of the PN neurons. Importantly, our data revealed six previously not known PN subtypes that are molecularly and spatially distinct. Interestingly, we found the PN subtypes exhibit differential vulnerability to partial loss of Atoh1 function, providing insights into the prominence of PN phenotypes in patients with ATOH1 missense mutations.