Biology subjects

Rognard, C.

Publications and source records attributed to Rognard, C..

4 recordsLinked to original sources

bioRxiv2026

Netrin-1 Acts as a Guardian of Naive Pluripotency in Human Embryonic Stem Cells

We investigated the role of Netrin-1 (NTN1) in human naive pluripotency using complementary loss- and gain-of-function approaches. In primate embryos and human embryonic stem cells (hESCs), Netrin-1 expression is associated with the naive pluripotent state. Disruption of NTN1 had no detectable effect on hESCs maintained on murine embryonic fibroblasts. However, under sub-optimal culture conditions, NTN1-knockout cells exhibited compromised naive pluripotency, which was rescued with feeder cells overexpressing Netrin-1. Netrin-1 overexpression in hESCs accelerated acquisition of the naive state and markedly increased resistance to differentiation. These effects were accompanied by extensive epigenetic remodeling, including H3K27ac and H2K27me3. Proteomic and phospho-proteomic analyses further revealed rapid Netrin-1-dependent alterations in pathways controlling cell adhesion, signaling, and chromatin regulation. Together, these findings extend the role of Netrin-1 beyond its established functions and identify it as a coordinator of extracellular cues, intracellular signaling, and nuclear regulatory mechanisms that support human naive pluripotency.

cell biology↗

bioRxiv2025

Identification of novel candidate regulators of human naive pluripotency by means of a genetic switch utilizing the chimeric receptor G-CSFR:GP130

This study investigated the molecular mechanisms underpinning the transition from primed to naive pluripotency in human pluripotent stem cells (hPSCs) by utilizing a dual genetic switch combining hormone-dependent STAT3-ERT2 and a chimeric GCSFR:gp130 receptor. Upon activation with tamoxifen and G-CSF, hPSCs demonstrated upregulation of naive markers, and sustained self-renewal independent of LIF. Transcriptomic analyses revealed distinct clusters of early response genes, with a subset of 26 genes significantly enriched in the human epiblast. Knockdown experiments further delineated essential regulators that modulate differentiation and proliferation during naive reprogramming including interferon gamma inducible protein (IFI)16 and interferon-induced transmembrane (IFITM) proteins. Moreover, functional assays using mutant chimeric GCSFR:gp130 receptor highlighted the critical role of JAK kinase recruitment in orchestrating epigenomic remodeling and early gene activation. This approach establishes a robust platform to dissect the signaling dynamics governing the accession of hPSCs to naive pluripotency.

cell biology↗

bioRxiv2023

Extensive remodelling of XIST regulatory networks during primate evolution

Unravelling how gene regulatory networks are remodelled during evolution is crucial to understand how species adapt to environmental changes. We addressed this question for X-chromosome inactivation, a process essential to female development that is governed, in eutherians, by the XIST lncRNA and its cis-regulators. To reach high resolution, we studied closely related primate species, spanning 55 million years of evolution. We show that the XIST regulatory circuitry has diversified extensively over such evolutionary timeframe. The insertion of a HERVK transposon has reshuffled XIST 3D interaction network in macaque embryonic stem cells (ESC) and XIST expression is maintained by the additive effects of the JPX lncRNA gene and a macaque specific enhancer. In contrast, JPX is the main contributor to XIST expression in human ESCs but is not significantly involved in XIST regulation in marmoset ESCs. None of these entities are however under purifying selection, which suggests that neutrally evolving non-coding elements harbour high adaptive potentials.

genomics↗

bioRxiv2020

Primate naive pluripotent stem cells stall in the G1 phase of the cell cycle and differentiate prematurely during embryo colonization

After reprogramming to naive pluripotency, human pluripotent stem cells (PSCs) still exhibit very low ability to make interspecies chimeras. Whether this is because they are inherently devoid of the attributes of chimeric competency or because naive PSCs cannot colonize embryos from distant species remains to be elucidated. Here, we have used different types of mouse, human and rhesus monkey naive PSCs and analyzed their ability to colonize rabbit and cynomolgus monkey embryos. Mouse embryonic stem cells (ESCs) remained mitotically active and efficiently colonized host embryos. In contrast, primate naive PSCs colonized host embryos with much lower efficiency. Unlike mouse ESCs, they slowed DNA replication after dissociation and, after injection into host embryos, they stalled in the G1 phase and differentiated prematurely, regardless of host species. We conclude that human and non-human primate naive PSCs do not efficiently make chimeras because they are inherently unfit to remain mitotically active during colonization.

cell biology↗