Project description:The integration of adult-born neurons in the existent neural circuitry is known to be activity-dependent. To decipher the underlying mechanisms, we genetically manipulated excitability of adult-born cells (via cell-specific overexpression of either Kv1.2 or Kir2.1 K+ channels). Longitudinal in vivo Ca2+ imaging and transcriptome analyses revealed that endogenous but not sensory-driven activity governs migration, morphogenesis, survival, and functional integration of adult-born juxtaglomerular neurons in the mouse olfactory bulb. The proper development of these cells required fluctuations of cytosolic Ca2+ levels, phosphorylation of CREB, and pCREB-mediated gene expression. Attenuating Ca2+ fluctuations via K+ channel overexpression strongly downregulated genes involved in neuronal migration, differentiation, and morphogenesis and upregulated the apoptosis-related genes, thus locking adult-born cells in the vulnerable and immature state. Together, the data identify signaling pathways connecting the endogenous intermittent neuronal activity/Ca2+ fluctuations as well as proper Kv1.2/Kir2.1 K+ channel function to migration, maturation, and survival of adult-born neurons.
Project description:Zebrafish display widespread and pronounced adult neurogenesis, which is fundamental for their regeneration capability after central nervous system injury. However, the cellular identity and the biological properties of adult newborn neurons are elusive for most brain areas. Here, we used short-term lineage tracing of radial glia progeny to prospectively isolate newborn neurons from the her4.1+ radial glia lineage in the homeostatic adult forebrain. Transcriptome analysis of radial glia, newborn neurons and mature neurons using single cell sequencing identified distinct transcriptional profiles including novel markers for each population. Specifically, we detected 2 separate newborn neuron types, which showed diversity of cell fate commitment and location. Further analyses showed homology of these cell types to neurogenic cells in the mammalian brain, identified neurogenic commitment in proliferating radial glia and indicated that glutamatergic projection neurons fate are generated in the adult zebrafish telecephalon. Thus, we prospectively isolated adult newborn neurons from the adult zebrafish forebrain, identified markers for newborn and mature neurons in the adult brain, revealed intrinsic heterogeneity among adult newborn neurons and their homology to mammalian adult neurogenic cell types.
Project description:In this study we applied the Terminal Amine Isotopic Labeling of Substrates (TAILS) technology to characterize the natural N-terminome of newborn and adult Bothrops jararaca venoms.
Project description:We used genome-wide sequencing methods to study the consequences of eliminating the CREB-binding protein (CBP) in newborn neurons. We found that CBP-deficient newborn neurons show impaired growth and activity-dependent transcription. In particular, genes downstream of the serum response factor (SRF) and related to neuronal growth and activity-dependent plasticity were affected. The expression of a constitutively active SRF protein with the ability to transactivate target genes in a CBP-independent manner reduced the growth and transcriptional defects associated with CBP ablation.
Project description:Well-balanced mitochondrial fission and fusion processes are essential for nervous system development. Loss of function of the main mitochondrial fission mediator, dynamin-related protein 1 (Drp1), is lethal early during embryonic development or around birth, but the role of mitochondrial fission in adult neurons remains unclear. Here we show that inducible Drp1 ablation in neurons of the adult mouse forebrain results in progressive, neuronal subtype-specific alterations of mitochondrial morphology in the hippocampus that are marginally responsive to antioxidant treatment. Furthermore, DRP1 loss affects synaptic transmission and memory function. Although these changes culminate in hippocampal atrophy, they are not sufficient to cause neuronal cell death within 10 weeks of genetic Drp1 ablation. Collectively, our in vivo observations clarify the role of mitochondrial fission in neurons, demonstrating that Drp1 ablation in adult forebrain neurons compromises critical neuronal functions without causing overt neurodegeneration.
Project description:As the unique organ, rumen plays vital roles in providing products for humans, however, the underlying cell composition and interactions with epithelium-attached microbes remain largely unknown. Herein, we performed an integrated analysis in single-cell transcriptome, epithelial microbiome, and metabolome of rumen tissues to explore the differences of microbiota-host crosstalk between newborn and adult cattle models. We found that fewer epithelial cell subtypes and more abundant immune cells (e.g., Th17 cells) in the rumen tissue of adult cattle. Metabolism-related functions and oxidation-reduction process were significantly upregulated in the adult rumen epithelial cell subtypes. The epithelial Desulfovibrio was significantly enriched in the adult cattle. To further clarify the role of Desulfovibrio in host’s oxidation-reduction process, we performed metabolomics analysis of rumen tissues and found that Desulfovibrio showed a high co-occurrence probability with the pyridoxal in the adult cattle compared with newborn ones. The adult rumen epithelial cell subtypes also showed stronger ability of pyridoxal binding. These indicates that Desulfovibrio and pyridoxal likely play important roles in maintaining redox balance in adult rumen. The integrated analysis provides novel insights into the understanding of rumen function and facilitate the future precision improvement of rumen function and milk/meat production in cattle.