Biology subjects

Ferron, S. R.

Publications and source records attributed to Ferron, S. R..

5 recordsLinked to original sources

bioRxiv2026

Afadin Loss Uncovers an Ectopic Neurogenic Niche and Reorganizes the Adult Ventricular-Subventricular Zone

Stem cells are generally thought to depend on specialized niches that provide signals for their long-term maintenance. Whether stem-cell competence is intrinsically constrained by anatomical organization remains unclear. Here, we show that neural stem cells can establish and sustain functional persistent stem-cell populations outside their normal anatomical context. Using developmental deletion of the cell-adhesion regulator Afadin as a tool to disrupt cortical tissue organization, we find that neural progenitors are displaced from the ventricular surface and establish an ectopic germinal zone (EGZ) into advanced adulthood. EGZ stem-cell populations retain self-renewal and multilineage differentiation capacity throughout this period. In parallel, the ventricular-subventricular zone (V-SVZ) undergoes persistent reorganization of tissue architecture, cellular composition, molecular state, and stem-cell activity. Together, these findings reveal unexpected plasticity in the relationship between stem cells and their tissue environment, suggesting that canonical niche anatomy may constrain where stem cells normally reside without defining the limits of functional stem-cell competence.

neuroscience↗

bioRxiv2025

TET2-dependent differential 5hmC deposition balances adult neural stem cell activation and differentiation

Ten-eleven translocation (TET) enzymes are key regulators of active DNA demethylation, converting 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) and thereby shaping the epigenetic landscape and cellular identity. While their roles have been characterized in pluripotent and some multipotent stem cells, their function in adult neural stem cells (NSCs) of the subventricular zone (SVZ) remains poorly understood. Here, we show that TET2 is critical for the maintenance and differentiation of adult NSCs, orchestrating locus-specific 5hmC deposition across promoters, gene bodies, and enhancers. Importantly, 5hmC remodeling segregates into two functionally distinct programs: promoter-associated gains of 5hmC are strongly TET2-dependent and drive transcription of genes controlling neural differentiation and calcium signaling, whereas gene body- and enhancer-associated 5hmC gains partially depend on TET2 and sustain proliferative and metabolic pathways, thereby maintaining stemness. Loss of TET2 disrupts these 5hmC programs, downregulates key differentiation- and calcium-related genes, and impairs the normal differentiation-associated increase in intracellular calcium, revealing a functional consequence of altered epigenetic regulation. Together, our findings uncover a pivotal role for TET2 in coordinating complementary epigenetic and transcriptional programs that balance stemness and differentiation in adult NSCs.

neuroscience↗

bioRxiv2025

TET3 protects the Dlk1-Dio3 Imprinted Locus from DNA hypomethylation during adult NSC Reprogramming

Genomic imprinting is an epigenetic mechanism that drives monoallelic gene expression depending on parental origin. Loss of imprinting (LOI) is associated with human imprinting disorders, fetal development, and cancer progression. Imprinted genes, organized in clusters, are regulated by methylation at imprint control regions (ICRs), differentially methylated regions (DMRs) between parental chromosomes. Somatic cell reprogramming into induced pluripotent stem cells (iPSCs) is a valuable tool for studying pluripotency and holds promise for patient-specific therapies. Discerning whether genomic imprinting changes during reprogramming represent epigenetic abnormalities or essential adaptations linked to pluripotency is crucial. Here, we perform RNA-seq and MeDIP-seq analysis on mouse iPSCs derived from neural stem cells (NSCs). Our findings reveal that ICRs undergo DNA hypomethylation, confirming widespread LOI in pluripotent cells. However, the IG-DMR within the Dlk1-Dio3 imprinted cluster resists hypomethylation, a hallmark of successful pluripotency acquisition. We also identify a non-canonical role of TET3 in IG-DMR methylation protection through transcriptional regulation of Oct4 and Trim28. These findings highlight genomic imprinting as a key mechanism of gene dosage control in pluripotency acquisition and maintenance.

cell biology↗

bioRxiv2022

The rates of adult neurogenesis and oligodendrogenesis are linked to cell cycle regulation through p27-dependent gene repression of SOX2

Cell differentiation involves profound changes in global gene expression that often have to occur in coordination with cell cycle exit. Because cyclin-dependent kinase inhibitor p27 reportedly regulates proliferation of neural progenitor cells in the subependymal neurogenic niche of the adult mouse brain, but can also have effects on gene expression, we decided to molecularly analyze its role in adult neurogenesis and oligodendrogenesis. At the cell level, we show that p27 restricts residual cyclin-dependent kinase activity after mitogen withdrawal to antagonize cycling, but it is not essential for cell cycle exit. Contrasting gene expression with chromatin accessibility, we find that p27 is coincidentally necessary to globally repress many genes involved in the transit from multipotentiality to differentiation, including those coding for neural progenitor transcription factors SOX2, OLIG2, and ASCL1. Our data reveal both direct association of p27 with regulatory sequences in the three genes and an additional hierarchical relationship where p27 repression of the Sox2 gene leads to reduced levels of SOX2-downstream targets Olig2 and Ascl1. In vivo, p27 is also required for the regulation of the proper level of SOX2 necessary for neuroblasts and oligodendroglial progenitor cells to timely exit cell cycle in a lineage-dependent manner.

neuroscience↗

bioRxiv2022

Imprinted genes Cdkn1c and Igf2 interact to promote terminal differentiation of adult NSCs

Genomic imprinting is implicated in the control of gene dosage in neurogenic niches. Insulin-like growth factor 2 (Igf2), is an imprinted gene that shows biallelic expression only in the vascular compartment contributing to neural stem cells (NSCs) maintenance in the subventricular zone (SVZ) niche. The effects of this factor in adult NSCs differentiation are not well defined. We show here that IGF2 promotes cell fate commitment of NSCs by inducing the expression of another imprinted gene, the maternally expressed gene cyclin-dependent kinase inhibitor 1c (Cdkn1c), which encodes for p57 protein, eliciting cell cycle exit and terminal differentiation into astrocytes, neurons and oligodendrocytes. Using a conditional mouse model with Cdkn1c-deficient neural progenitors, we confirm that IGF2 and p57 interact in a common pathway to regulate the differentiation program of adult NSCs. This occurs through a mechanism involving the PI3K-Akt pathway that mediates regulation of p57 expression. We also show that the imprinted state of the Cdkn1c gene is not altered after IGF2 treatment confirming maternal expression of the gene in NSCs. Our results identify a molecular mechanism by which a paracrine factor produced and secreted by the neurogenic niche compartment can modulate Cdkn1c dosage to trigger differentiation of adult NSCs.

neuroscience↗