0000000000008538
AUTHOR
Filippo Calzolari
Direct In Vitro Reprogramming of Astrocytes into Induced Neurons
Spontaneous neuronal replacement is almost absent in the postnatal mammalian nervous system. However, several studies have shown that both early postnatal and adult astroglia can be reprogrammed in vitro or in vivo by forced expression of proneural transcription factors, such as Neurogenin-2 or Achaete-scute homolog 1 (Ascl1), to acquire a neuronal fate. The reprogramming process stably induces properties such as distinctly neuronal morphology, expression of neuron-specific proteins, and the gain of mature neuronal functional features. Direct conversion of astroglia into neurons thus possesses potential as a basis for cell-based strategies against neurological diseases. In this chapter, we …
Resolving the transcriptional transitions associated with oligodendrocyte generation from adult neural stem cells by single cell sequencing
AbstractThe subventricular zone (SVZ) is the largest neurogenic niche in the adult forebrain. Notably, neural stem cells (NSCs) of the SVZ generate not only neurons, but also oligodendrocytes, the myelin-forming cells of the central nervous system. Transcriptomic studies have provided detailed knowledge of the molecular events that regulate neurogenesis, but little is understood about adult oligodendrogenesis from SVZ-NSCs. To address this, we performed in-depth single-cell transcriptomic analyses to resolve the major differences in neuronal and oligodendroglial lineages derived from the adult SVZ. A hallmark of adult oligodendrogenesis was the stage-specific expression of transcriptional m…
Subtle Changes in Clonal Dynamics Underlie the Age-Related Decline in Neurogenesis
SUMMARYNeural stem cells in the adult murine brain have only a limited capacity to self-renew, and the number of neurons they generate drastically declines with age. How cellular dynamics sustain neurogenesis and how alterations with age may result in this decline, are both unresolved issues. Therefore, we clonally traced neural stem cell lineages using confetti reporters in young and middle-aged adult mice. To understand underlying mechanisms, we derived mathematical population models of adult neurogenesis that explain the observed clonal cell type abundances. Models fitting the data best consistently show self renewal of transit amplifying progenitors and rapid neuroblast cell cycle exit.…
Increasing Neural Stem Cell Division Asymmetry and Quiescence Are Predicted to Contribute to the Age-Related Decline in Neurogenesis.
Summary: Adult murine neural stem cells (NSCs) generate neurons in drastically declining numbers with age. How cellular dynamics sustain neurogenesis and how alterations with age may result in this decline are unresolved issues. We therefore clonally traced NSC lineages using confetti reporters in young and middle-aged adult mice. To understand the underlying mechanisms, we derived mathematical models that explain observed clonal cell type abundances. The best models consistently show self-renewal of transit-amplifying progenitors and rapid neuroblast cell cycle exit. In middle-aged mice, we identified an increased probability of asymmetric stem cell divisions at the expense of symmetric di…
Drug connectivity mapping and functional analysis reveals therapeutic small molecules that differentially modulate myelination
AbstractOligodendrocytes are the myelin forming cells of the central nervous system (CNS) and are generated from oligodendrocyte progenitor cells (OPCs). Disruption or loss of oligodendrocytes and myelin has devastating effects on CNS function and integrity, which occurs in diverse neurological disorders, including Multiple Sclerosis (MS), Alzheimer’s disease (AD) and neuropsychiatric disorders. Hence, there is a need to develop new therapies that promote oligodendrocyte regeneration and myelin repair. A promising approach is drug repurposing, but most agents have potentially contrasting biological actions depending on the cellular context and their dose-dependent effects on intracellular r…
Drug connectivity mapping and functional analysis reveal therapeutic small molecules that differentially modulate myelination
Disruption or loss of oligodendrocytes (OLs) and myelin has devastating effects on CNS function and integrity, which occur in diverse neurological disorders, including Multiple Sclerosis (MS), Alzheimer’s disease and neuropsychiatric disorders. Hence, there is a need to develop new therapies that promote oligodendrocyte regeneration and myelin repair. A promising approach is drug repurposing, but most agents have potentially contrasting biological actions depending on the cellular context and their dose-dependent effects on intracellular pathways. Here, we have used a combined systems biology and neurobiological approach to identify compounds that exert positive and negative effects on olig…