MEYRONET, D. | bioRxiv Science

bioRxiv2025

Lineage of origin-specific developmental programs drive the behaviors of malignant cells in an avian embryo model of human Medulloblastoma subgroups

Tumoral cells of medulloblastoma (MB) subgroups (SHH, G3 and G4) display a close transcriptomic proximity to early neuronal progenitors that migrate to form the embryonic cerebellum. With the aim of exploring functional proximities between MB cells and their physiological counterparts, we established a model of transplantation of human MB cells into the cerebellum of chick embryos in vivo and ex ovo. Light-sheet imaging of embryos grafted with cell lines and patient biopsies of MB SHH, G3 and G4 revealed the formation of primary tumors within a few days, whose topography matched that of the different MB subgroups on patients MRI. We found that transplanted MB cells adopted morphological and migratory features specific of their respective lineage of origin. Combining transcriptomic and functional approaches, we found that MB G3 tumoral cells exploit the canonical SLIT migration developmental signaling at disease emergence. This signaling is maintained in MB G3 patients and is associated with tumor aggressivity and poor prognosis.

cancer biology↗

bioRxiv2021

RSL24D1 sustains steady-state ribosome biogenesis and pluripotency translational programs in embryonic stem cells.

Embryonic stem cell (ESC) fate decisions are regulated by a complex molecular circuitry that requires tight and coordinated gene expression regulations at multiple levels from chromatin organization to mRNA processing. Recently, ribosome biogenesis and translation have emerged as key regulatory pathways that efficiently control stem cell homeostasis. However, the molecular mechanisms underlying the regulation of these pathways remain largely unknown to date. Here, we analyzed the expression, in mouse ESCs, of over 300 genes involved in ribosome biogenesis and we identified RSL24D1 as the most differentially expressed between self-renewing and differentiated ESCs. RSL24D1 is highly expressed in multiple mouse pluripotent stem cell models and its expression profile is conserved in human ESCs. RSL24D1 is associated with nuclear pre-ribosomes and is required for the maturation and the synthesis of 60S subunits in mouse ESCs. Interestingly, RSL24D1 depletion significantly impairs global translation, particularly of key pluripotency factors, including POU5F1 and NANOG, as well as components of the polycomb repressive complex 2 (PRC2). Consistently, RSL24D1 is required for mouse ESC self-renewal and proliferation. Taken together, we show that RSL24D1-dependant ribosome biogenesis is required to both sustain the expression of pluripotent transcriptional programs and silence developmental programs, which concertedly dictate ESC homeostasis.

developmental biology↗