Biology subjects

Pastor-Alonso, O.

Publications and source records attributed to Pastor-Alonso, O..

6 recordsLinked to original sources

bioRxiv2026

Spatial and Molecular Progression of Neural Progenitor Cells in the Developing Human Dentate Gyrus

The large diversity of neuronal and glial cell types in the human brain is underpinned by foundational cell populations known as neural progenitor cells (NPCs). The dentate gyrus (DG) of the hippocampus, a key structure in learning and memory, maintains a tightly organized NPC population into adulthood across many mammalian species. However, the emergence, organization and persistence of NPCs in the human hippocampus remain poorly characterized. Reports of NPCs in the juvenile, adult, and aged periods have been variable, reflecting differences in identification criteria and highlighting the need for a unified framework across development. In this study, we provide a spatial and molecular map of the developmental trajectory of NPCs in the human DG, combining multimodal transcriptomic analysis within a neuroanatomical context. At mid-gestation, we observed changes in the structural and cellular arrangement of the hippocampus, coinciding with the emergence of a multicellular NPC layer within the DG, herein named the granular-hilar progenitor zone (GHPZ). Neurogenic transcriptomic signatures in the GHPZ were diminished by early infancy, coinciding with a reduction in NPC number as they progressed toward an astrocytic program. At childhood, the GHPZ dissolved with only sparse radial NPCs remaining in the DG. Lastly, we validated WNT signaling pathway-associated genes as NPC identity markers in the developing human DG, observing a decline in their expression after infancy. Our study defines the steep decline of NPCs from gestation to the postnatal period, identifies their progression to an astrocytic nature, and sets the molecular blueprint for NPC identification in the human DG. HighlightsO_LIMultimodal mapping of neural progenitor cells from gestational to postnatal stages in the human hippocampus C_LIO_LIFormation of the granular-hilar progenitor zone within the dentate gyrus at mid-gestation C_LIO_LINeurogenic potential declines sharply from the prenatal period to childhood, with radial glia cells progressively acquiring astrocytic features C_LIO_LIDevelopmental modulation of the WNT signaling pathway accompanies radial glia cell transitions C_LI

neuroscience↗

bioRxiv2026

A Single-Cell and Spatial 3D Multi-omic Atlas of Developing Human Basal Ganglia and Inhibitory Neurons

The human basal ganglia (BG), subcortical nuclei fundamental to motor regulation and cognitive modulation, is constructed from neurons produced during gestation in the adjacent ganglionic eminences (GEs). GEs are transient structures in the ventral prenatal brain that also generate GABAergic inhibitory neurons which migrate to destinations in the BG, cortex and other destinations. This study aims to elucidate the epigenomic and 3D-genomic dynamics involved in the specification and maturation of GEs and GE-derived neurons, using single-nucleus methyl-3C sequencing (snm3C-seq), highly-multiplexed spatial transcriptomics, and chromatin+RNA single-molecule imaging. Our multi-modal data support a heterogeneous temporal progression across GE subregions, with the lateral GE (LGE) showing declining neurogenic activity in mid-gestation and caudal GE (CGE) exhibiting ongoing developmental progression through infancy. We identified regulatory programs that specify subtypes of BG principal cells, medium spiny neurons (MSN), via synchronized maturation of the 3D-epigenome. In infant brains, we found a transient short-range enriched (SE) chromatin conformation during the transition between oligodendrocyte progenitors (OPCs) and oligodendrocytes (ODCs), and a temporary shift toward Long-range Enriched (LE) chromatin conformation in projection neurons, extending previous works showing the differentiation of neurons and glial cells is associated with permanent SE and LE conformation, respectively. Lastly, we found that gene regulatory regions active in MSNs were enriched in loci associated with genetic risk for neuropsychiatric disease. Our study delineates the highly complex, lineage-specific 3D genomic dynamics in ventral progenitors and basal ganglia populations of the perinatal human brain. HighlightsO_LIJoint 3D genome and DNA methylome analysis of ventral brain progenitor zones C_LIO_LIHeterogeneous developmental progressions of the ganglionic eminences C_LIO_LIDistinct development dynamics and regulatory landscape of MSNs and interneurons C_LIO_LITransient remodeling of the 3D-genome in neurons and oligodendrocyte progenitors C_LI

genomics↗

bioRxiv2022

Generation of adult hippocampal neural stem cells occurs in the early postnatal dentate gyrus and depends on cyclin D2

In the hippocampus, lifelong neurogenesis is maintained by a pool of multipotent adult neural stem cells (aNSCs) residing in the subgranular zone of the dentate gyrus (DG). Yet, the mechanisms guiding the transition of NSCs from developmental to adult remain unclear. By using nestin-reporter mice deficient for D2, a cyclin expressed mainly postnatally, we show that the aNSC pool is established through D2-dependent proliferation during the first two weeks of life. The absence of D2 allows the normal development of the DG until birth but prevents the postnatal formation of radial glia-like aNSCs. Additionally, retroviral fate mapping demonstrates that aNSCs are born on-site from precursors located in the DG shortly after birth. Altogether, our data suggest that aNSCs are a population distinct from developmental NSCs and thus imply that adult hippocampal neurogenesis is not a mere continuation of development.

neuroscience↗

bioRxiv2022

HB-EGF and zinc activate EGFR to induce reactive neural stem cells in the mouse hippocampus after seizures

Hippocampal seizures mimicking mesial temporal lobe epilepsy (MTLE) cause a profound disruption of the adult neurogenic niche in mice. Seizures provoke neural stem cells to switch to a reactive phenotype (reactive-neural stem cells, React-NSCs)) characterized by multibranched hypertrophic morphology, massive activation to enter mitosis, symmetric division and final differentiation into reactive astrocytes. As a result, neurogenesis is chronically impaired. Here we, using a mouse model of MTLE, show that the epidermal growth factor receptor (EGFR) signalization pathway is key for the induction of React-NSCs and that its inhibition exerts a beneficial effect on the neurogenic niche. We show that during the initial days after the induction of seizures by a single intrahippocampal injection of kainic acid, a strong release of zinc and heparin-binding epidermal growth factor, both activators of the EGFR signalization pathway in neural stem cells, is produced. Administration of the EGFR inhibitor gefitinib, a chemotherapeutic in clinical phase IV, prevents the induction of React-NSCs and preserves neurogenesis. SignificanceIn mouse models of MTLE-HS, seizures cause a profound disruption of the hippocampal neurogenic niche and neurogenesis results chronically impaired, in agreement with what occurs in the human MTLE-HS hippocampus. Thus, the normal cognitive functions associated with neurogenesis are altered, but also the endogenous regenerative capacity that could compensate the high rate of neurons in the granule cell layer of the dentate gyrus. We provide here for the first time a molecular mechanism (the EGFR transduction pathway) regulating the induction of React-NSCs.

neuroscience↗

bioRxiv2019

Antiviral activity of N-ω-Chloroacetyl-L-Ornithine on in vitro replication of Chikungunya virus

The infections causes by Chikungunya virus (CHIKV), family Togaviridae, genus Alfavirus, have become a health problem around the world, due to its widespread occurrence, the high morbidity rate and the absence of vaccines or antiviral treatments. We analyzed a competitive inhibitor of ornithine decarboxylase, enzyme key in the biosynthesis of Polyamines (PAs), N-{omega}-chloroacetyl-L-ornithine (NCAO), as a possible inhibitor of CHIKV replication because intracellular polyamines participate in the transcription and in vitro translation of CHIKV. NCAO does not have any cytotoxic effect on C6/36 cells even at a concentration of 1000M at 72h after post-exposure but in Vero cells the cytotoxic effect was presented above 380M at 48h post-exposure, which was considered when determining the inhibitory effect on viral replication. We demonstrate that NCAO inhibits the replication of CHIKV in Vero and C6/36 cells in a dose-dependent manner causing a decrease in the PFU/mL of at least 4-logarithm (p <0.01) in both cell lines. Viral yields were restored by the addition of exogenous polyamines, mainly putrescine. HPLC analyses it shown that NCAO decrease content of intracellular PAs even though in infected cells mainly decreased spermidine and spermine, so NCAO inhibits CHIKV replication, by depleting the intracellular polyamines in Vero and C6/36 cells, suggesting that this compound is a possible antiviral in CHIKV infections.\n\nImportanceThe infections caused by Chikungunya virus (CHIKV), genus Alfavirus, have become a worldwide health problem, due to its high morbidity rate and the absence of vaccines or antiviral treatments. It is known that CHIKV use intracellular poliamines during transcription and traduction process, so the depletion of intracellular putrescine, spermidine and spermine reduce the viral replication. N-{omega}-chloroacetyl-L-ornithine (NCAO) is known as a competitive inhibitor of ornithine decarboxylase, key enzyme in Polyamines biosynthesis, but no studies have proven its activity on the inhibition of polyamine-dependent viral replication. Here we demonstrate NCAO inhibits in vitro CHIKV replication, so we propose NCAO as an antiviral candidate.

microbiology↗

bioRxiv2018

Human Dental Pulp Stem Cells Grown In Neurogenic Media Differentiate Into Endothelial Cells And Promote Neovasculogenesis In The Mouse Brain.

Dental Pulp Stem Cells (DPSCs) have a demonstrated capacity to acquire neuronal-like phenotypes, suggesting their use in brain cell therapies. In the present work, we wanted to address the phenotypic fate of adult DPSCs cultured in Neurocult media (Stem Cell Technologies), a cell culture medium without serum routinely used for the expansion of adult neural stem cells (NSCs). Our results showed for the first time, that non-genetically modified adult DPSCs cultured with Neurocult generated neurosphere-like dentospheres expressing the NSC markers Nestin and GFAP, but also the vascular endothelial cell marker CD31. One month post-intracranial graft into athymic nude mice, human CD31+ or Nestin+ DPSC-derived cells were found tightly associated with brain blood vessels increasing their laminin staining. These results suggest that DPSCs integrated and contributed to an increased generation of neovasculature within brain tissue and that Neurocult medium constituted a fast and efficient way to obtain endothelial cells from human DPSCs.

bioengineering↗