Biology subjects

Vitali, I.

Publications and source records attributed to Vitali, I..

5 recordsLinked to original sources

bioRxiv2025

A single-cell transcriptomic atlas maps cerebellar astrocyte diversity and uncovers the transcriptional code underlying their maturation trajectories

Astrocytes are increasingly recognized as key regulators of neural circuit development and function, with mounting evidence revealing substantial heterogeneity within and across brain regions. Yet, the full extent of this diversity and its developmental mechanisms remain poorly understood. To address this, we leveraged the uniqueness of the mouse cerebellum, which hosts well-defined astrocyte types and established progenitor pools. Through complementary multi-modal omic approaches, including single-cell RNA sequencing, spatial transcriptomics, trajectory inference, clonal lineage reconstruction, and gene expression and regulatory network analyses, we systematically dissected the molecular diversity and ontogenesis of cerebellar astrocytes. We identified known types and uncovered new subtypes with functional specialization, inferring their developmental trajectories from multiple embryonic niches and postnatal progenitor sources with fate divergence, convergence, and restriction. We further predicted a hierarchical transcriptional regulator code governing this diversification, operating at multiple levels: distinct regulatory modules i) reflect embryonic regionalization and lineage; ii) determine broad astroglial identity; specify iii) Bergmann versus non-Bergmann fates; and guide iv) astrocyte type and v) subtype acquisition. Our findings map and temporally organize transcriptional programs that capture key determinants of astrocyte fate, integrating them along defined trajectories toward diverse astrocyte identities. This high-resolution framework for cerebellar glial diversification offers a model to be challenged across other brain regions.

neuroscience↗

bioRxiv2024

Nfib regulates progenitor competence in maturation of GABAergic neurons

Diverse types of GABAergic projection neurons and interneurons of the telencephalon derive from progenitors in a ventral germinal zone, called the ganglionic eminence. Using single-cell transcriptomics, chromatin accessibility profiling, lineage tracing, birthdating, heterochronic transplantation, and perturbation sequencing in mouse embryos, we investigated how progenitor competence influences the maturation and differentiation of these neurons. We found that the progression of neurogenesis over developmental time shapes maturation competence in ganglionic eminence progenitors, influencing how they progress into mature states. In contrast, differentiation competence, which defines the ability to produce diverse transcriptomic identities, remains largely unaffected by the stages of neurogenesis. Chromatin remodeling alongside a NFIB-driven regulatory gene module influences maturation competence in late-born neurons. These findings provide key insights into how transcriptional programs and chromatin accessibility govern neuronal maturation and the diversification of GABAergic neuron subtypes during neurodevelopment.

neuroscience↗

bioRxiv2023

Dual lineage origins of neocortical astrocytes

Astrocytes represent one of the most abundant cell types in the central nervous system, and play an essential role in nearly all aspects of brain functions1. Recent studies have challenged the notion that cortical astrocytes are a uniform population, and have highlighted their diverse characteristics at the morphological, molecular, and functional levels2-5. However, how this diversity originates and establishes during cortical development, remains largely unknown. Using single-cell RNA sequencing, we identified five distinct astrocyte subtypes displaying unique spatial patterns in the mouse neocortex, and discovered essential regulators for their formation. Furthermore, we used TrackerSeq6, a method that integrates heritable DNA barcodes into the genome of electroporated progenitors, to track clonally related astrocytes, and identified two distinct lineages that give rise to the five astrocyte subtypes. The first lineage derives from Emx1+ multipotent progenitors that first generate neurons and then switch to produce cortical astrocytes. The second lineage stems from a fate-restricted progenitor population that exclusively gives rise to a specific subset of cortical astrocytes, marked by Olig2. The knockout of this gene in cortical progenitors is sufficient to promote a fate switch between the two lineages. These findings offer novel insights into the cellular mechanisms underlying astrocyte diversity, highlighting the presence of multiple progenitor subtypes, responsible for generating distinct subtypes of astrocytes.

neuroscience↗

bioRxiv2023

Spatial enhancer activation determines inhibitory neuron identity

The mammalian telencephalon contains a tremendous diversity of GABAergic projection neuron and interneuron types, that originate in a germinal zone of the embryonic basal ganglia. How genetic information in this transient structure is transformed into different cell types is not yet fully understood. Using a combination of in vivo CRISPR perturbation, lineage tracing, and ChIP-seq in mice, we found that the transcription factor MEIS2 favors the development of projection neurons through genomic binding sites in regulatory enhancers of projection neuron specific genes. MEIS2 requires the presence of the homeodomain transcription factor DLX5 to direct its functional activity towards these sites. In interneuron precursors, the activation of projection neuron specific enhancers by MEIS2 and DLX5 is repressed by the transcription factor LHX6. When MEIS2 carries a mutation associated with intellectual disability in humans, it is less effective at activating enhancers involved in projection neuron development. This suggests that GABAergic differentiation may be impaired in patients carrying this mutation. Our research supports a model ("Differential Binding ) where the spatial specific composition of transcription factors at cis-regulatory elements determines differential gene expression and cell fate decisions in the ganglionic eminence.

developmental biology↗

bioRxiv2018

Single-cell transcriptional dynamics and origins of neuronal diversity in the developing mouse neocortex

During cortical development, distinct subtypes of glutamatergic neurons are sequentially born and differentiate from dynamic populations of progenitors. The neurogenic competence of these progenitors progresses as corticogenesis proceeds; likewise, newborn neurons transit through sequential states as they differentiate. Here, we trace the developmental transcriptional trajectories of successive generations of apical progenitors (APs) and isochronic cohorts of their daughter neurons using parallel single-cell RNA sequencing between embryonic day (E) 12 and E15 in the mouse cerebral cortex. Our results identify the birthdate- and differentiation stage-related transcriptional dynamics at play during corticogenesis. As corticogenesis proceeds, APs transit through embryonic age-dependent molecular states, which are transmitted to their progeny to generate successive initial daughter cell identities. In neurons, essentially conserved post-mitotic differentiation programs are applied onto these distinct AP-derived ground states, allowing temporally-regulated sequential emergence of specialized neuronal cell types. Molecular temporal patterning of sequentially-born daughter neurons by their respective mother cell thus underlies emergence of neuronal diversity in the neocortex.\n\nOne Sentence SummaryDuring corticogenesis, temporally dynamic molecular birthmarks are transmitted from progenitors to their post-mitotic progeny to generate neuronal diversity.

neuroscience↗