Biology subjects

Ripoll, C.

Publications and source records attributed to Ripoll, C..

6 recordsLinked to original sources

bioRxiv2025

Multi-omics characterization of IDH-mutant astrocytoma-derived cell lines reveals NOTCH-regulated plastic quiescent astrocyte-like state

Diffuse IDH-mutant astrocytomas are brain tumors typically diagnosed as low-grade but capable of progressing to higher grades. They exhibit three cellular states resembling astrocytes, oligodendrocytes, and neural progenitor (NPC) cells. Understanding their biology has been challenging due to the lack of relevant in vitro models. Here we established and extensively characterized four astrocytoma cell lines (LGG275, LGG336, LGG85, LGG349) derived from IDH-mutant astrocytoma at different grades, cultured in defined media and analyzed by multi-omics. These lines display growth rates in vitro and in vivo consistent with tumor grade and recapitulate key molecular alterations observed in patient tumors, including IDH1, ATRX, and TP53 mutations, activation of the alternative lengthening of telomeres (ALT) pathway and, in the most aggressive line, amplification of MET and PDGFRA. Single-cell RNA sequencing showed that the 4 astrocytoma lines maintain the three major cellular states observed in patient tumors. A hallmark of higher-grade-derived lines (LGG85, LGG349) is the persistence of NPC-like populations without growth factors, reflecting tumor progression. The LGG275 line most accurately mirrors slow-growing astrocytomas. Using CD44 and GLAST, we isolated astrocyte-like (CD44+/GLAST+) cells from LGG275 that preferentially adopt a quiescent state yet retain remarkable plasticity, generating oligodendrocyte-like cells (CD44-/GLAST-). Transcriptomic and proteomic analyses revealed that astrocyte-like and oligodendrocyte-like cells populations resemble quiescent and activated neural stem (NSC) cells from the adult subventricular zone (SVZ). Finally, we found that NOTCH signaling regulates the balance between astrocytic and oligodendrocytic states, while DLL3, expressed by oligodendrocyte-like cells, modulates both proliferation and phenotype. These cell lines represent valuable resources for dissecting lineage dynamics, heterogeneity, and progression mechanisms in IDH-mutant astrocytomas. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=118 SRC="FIGDIR/small/696808v1_ufig1.gif" ALT="Figure 1"> View larger version (33K): org.highwire.dtl.DTLVardef@953108org.highwire.dtl.DTLVardef@c6234aorg.highwire.dtl.DTLVardef@3703fcorg.highwire.dtl.DTLVardef@1e6c3a9_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightO_LIWe constituted a richly annotated biobank derived from 4 astrocytomas, showing similar characteristics to those found in patients, providing valuable tools to investigate cellular heterogeneity and plasticity, and link with tumor progression. C_LIO_LIscRNA-sequencing revealed three cell states (oligodendrocyte-like, astrocyte-like, and stem cell-like cells) akin to those found in tumors. C_LIO_LIAstrocyte-like cells are quiescent cells, plastic and similar to quiescent neural stem cell (qNSC) from the sub-ventricular zone (SVZ), while oligodendrocyte-like cells are similar to active NSC (aNSC). C_LIO_LIThe Notch pathway plays a role in cell plasticity, enabling a shift towards an astrocyte-like state. C_LI

cancer biology↗

bioRxiv2025

Hippo/YAP1 Signaling Regulates the Oligodendrocyte-Astrocyte Fate Switch and Ependymal Gene Expression in Adult Spinal Cord Stem Cells

The adult mammalian spinal cord harbors ependymal cells that retain neural stem-cell properties. Although they possess a latent capacity to generate oligodendrocytes, these cells predominantly differentiate into astrocytes after injury. The molecular cues that govern their lineage commitment toward astrocytic versus oligodendroglial fates remain poorly defined. In this study, we addressed this gap in vitro by investigating the emergence of PDGFRA oligodendrocyte precursor cells (OPCs) in neurosphere cultures derived from adult spinal cord stem cells. We first observed that neurosphere cells exhibited a hybrid identity, co-expressing transcription factors of both astrocytic (NFIA, SOX9) and oligodendrocytic (OLIG1/2, SOX4, NKX2.2, TCF4) lineages. Upon differentiation, oligodendrocytic transcription factors were selectively maintained in OPCs but reduced in other cells. Using PdgfraH2B-GFP mice, we then isolated newly formed PDGFRA OPCs from neurospheres and performed multi-omic profiling. OPC formation was associated with the upregulation of chromatin remodelers and the downregulation of stem-cell markers such as EGFR, HES1, and TNC. Strikingly, OPC specification coincided with reduced expression of YAP1 and its partner TEAD1, key effectors of the Hippo pathway. Functional analyses revealed that YAP1 loss enhanced oligodendrocytic differentiation while reducing astrocytic and ependymal/cilia-associated gene expression. Conversely, constitutive YAP1 activation blocked differentiation into both lineages and promoted an ependymal-like transcriptional program, including upregulation of the ependymal marker CD24a and cilia-related proteins such as CROCC (Rootletin). Collectively, these findings uncover previously unrecognized roles for YAP1 in adult spinal cord stem-cell fate decisions and provide a molecular framework for leveraging these cells in regenerative strategies targeting spinal cord repair.

cell biology↗

bioRxiv2025

Endothelin Signaling via EDNRB receptor Reduces Proliferation and Promotes Proneural-to-Mesenchymal Transition in Gliomas

Diffuse gliomas are incurable primary brain tumors encompassing three histo-molecular subtypes: glioblastomas (GB), astrocytomas, and oligodendrogliomas. The latter two harbor IDH1 mutations and exhibit slower progression than glioblastomas. Diffuse gliomas are composed of highly plastic tumor cells capable of transitioning between astrocyte-like, oligodendrocyte-like, progenitor-like, and mesenchymal-like states, driven by genetic alterations and microenvironmental cues. The proneural-to-mesenchymal transition (PMT), associated with increased malignancy, is notably influenced by cytokines in the tumor microenvironment. Endothelin cytokines (ET-1, ET-2, ET-3), primarily secreted by vascular cells, regulate not only vascular tone but also astrocyte and neural stem cell proliferation via the G-protein-coupled receptors EDNRA and EDNRB. Prior studies using serum-cultured glioma lines suggested pro-proliferative effects of endothelins; however, such models poorly recapitulate the in vivo glioma context. In this study, we comprehensively revisited endothelin signaling - covering receptor expression, regulation, downstream pathways, and cellular responses-using eleven serum-free, patient-derived glioma lines (glioblastomas, IDH-wt and IDH-mutant oligodendrogliomas and astrocytomas), along with primary tumor samples. Multi-omics and electrophysiological analyses revealed EDNRB as the predominant receptor, enriched in astrocyte-like cells, upregulated by BMPs or growth factor withdrawal, and downregulated by interferons, IL-6 cytokines, endothelins, and Hippo/YAP activation. In contrast, EDNRA was expressed by a perivascular tumor subpopulation and induced by Notch signaling in glioblastomas but not in IDH1-mutant cells. Functionally, endothelins reduced proliferation across all models while promoting migration and PMT. Mechanistically, EDNRB activation increased intracellular Ca{superscript 2} and activated ERK, STAT3, and apamin-sensitive SK2/SK3 potassium channels. These findings identify endothelin signaling as an important regulator of glioma cell plasticity and behavior. HighlightsO_LIEDNRB is the predominant endothelin receptor expressed in glioma cells, with a small subset of tumor cells expressing EDNRA in close proximity to blood vessels C_LIO_LIEndothelin signaling reduces proliferation while promoting cell migration and Proneural-to-Mesenchymal transition C_LIO_LIEndothelin activates downstream Ca2+, K+, ERK, and STAT3 signaling pathways C_LIO_LIEDNRB expression is both positively and negatively regulated by inflammatory cytokines and the Hippo/YAP1 pathway, whereas EDNRA is upregulated by Notch signaling and hypoxia C_LI

cancer biology↗

bioRxiv2023

Syndecan-1 as specific cerebrospinal fluid biomarker of multiple sclerosis

Multiple sclerosis (MS) is an inflammatory demyelinating disease often characterized by remission and relapse periods occurring at irregular intervals after an initial attack (clinically isolated syndrome) and followed by a gradual progression of disability. Clinical symptoms, magnetic resonance imaging and abnormalities in cerebrospinal fluid (CSF) immunoglobulin profile allow diagnosis with a good sensitivity. However, current biomarkers lack specificity or have poor individual prognostic value. To identify novel candidate biomarkers of MS, we analysed 1) the CSF proteome from symptomatic controls and patients with clinically isolated syndrome or remitting-relapsing multiple sclerosis (n=40), and 2) changes in oligodendrocyte secretome upon proinflammatory or pro-apoptotic treatment. Proteins exhibiting differences in abundance in both studies were combined with previously described MS biomarkers to build a list of 87 proteins that were quantified by parallel reaction monitoring (PRM) in CSF samples from a new cohort comprising symptomatic controls and MS patients at different disease stages (n=60). The eleven proteins that passed this qualification step were subjected to a new PRM assay from a larger cohort (n=158) comprising patients with MS at different disease stages or with other inflammatory or non-inflammatory neurological disorders. Collectively, these studies identified a biomarker signature of MS that might improve MS diagnosis and prognosis. These include the oligodendrocyte precursor cell proteoglycan Syndecan-1, which was more efficient than previously described biomarkers to discriminate MS from other inflammatory and non-inflammatory neurological disorders.

neuroscience↗

bioRxiv2022

Persistence of FoxJ1+ Pax6+ Sox2+ ependymal cells throughout life in the human spinal cord

Spinal cord ependymal cells have stem cell properties in mice. They surround the central canal and keep expressing spinal cord developmental transcription factors. Similar cells exist in young humans however their persistence with aging is debated. We clarified this issue by collecting 17 spinal cords from organ donors, aged between 37 and 83 years old. We examined the presence of ependymal cells using immunohistochemistry on lightly-fixed tissue. We found the presence of cells expressing the typical ependymal marker FOXJ1 in the spinal cord central region in 100% of cases. In addition, a lumen surrounded by FOXJ1+ cells was observed in half of the cases. Like in mice, these human ependymal cells maintain the expression of SOX2 and PAX6 proteins together with RFX2 a master transcriptional regulator of ciliogenesis and ARL13B, a regulatory GTPase enriched in cilia. Reminiscent of the situation observed in mice and in young human spinal cord, a fetal-like regionalization of neurodevelopmental transcription factors was observed in three donors aged over 75 years: MSX1 and ARX/FOXA2 was preferentially expressed by dorsal and ventral ependymal cells, respectively. These results provide new evidence for the persistence of ependymal cells expressing neurodevelopmental genes throughout human life. The persistence of these cells in humans opens new opportunities to regenerate the spinal cord.

neuroscience↗

bioRxiv2021

Reaction of ependymal cells to spinal cord injury: a potential role for oncostatin pathway and microglial cells

Ependymal cells with stem cell properties reside in the adult spinal cord around the central canal. They rapidly activate and proliferate after spinal cord injury, constituting a source of new cells. They produce neurons and glial cells in lower vertebrates but they mainly generate glial cells in mammals. The mechanisms underlying their activation and their glial-biased differentiation in mammals remain ill-defined. This represents an obstacle to control these cells. We addressed this issue using RNA profiling of ependymal cells before and after injury. We found that these cells activate STAT3 and ERK/MAPK signaling during injury and downregulate cilia-associated genes and FOXJ1, a central transcription factor in ciliogenesis. Conversely, they upregulate 510 genes, six of them more than 20 fold, namely Crym, Ecm1, Ifi202b, Nupr1, Rbp1, Thbs2 and Osmr. OSMR is the receptor for the inflammatory cytokine oncostatin (OSM) and we studied its regulation and role using neurospheres derived from ependymal cells. We found that OSM induces strong OSMR and p-STAT3 expression together with proliferation reduction and astrocytic differentiation. Conversely, production of oligodendrocyte-lineage OLIG1+ cells was reduced. OSM is specifically expressed by microglial cells and was strongly upregulated after injury. We observed microglial cells apposed to ependymal cells in vivo and co-cultures experiments showed that these cells upregulate OSMR in neurosphere cells. Collectively, these results support the notion that microglial cells and OSMR/OSM pathway regulate ependymal cells in injury. In addition, the generated high throughput data provides a unique molecular resource to study how ependymal cell react to spinal cord lesion.

cell biology↗