Biology subjects

Monsoro-Burq, A. H.

Publications and source records attributed to Monsoro-Burq, A. H..

11 recordsLinked to original sources

bioRxiv2026

MicroRNA miR-219 is required for neural border and neural crest development in Xenopus neurulas

Neural crest (NC) multipotent stem cells give rise to many tissues including most of the peripheral nervous system, pigment cells and the craniofacial mesenchyme and skeleton. During gastrulation and early neurulation, cranial NC cells are specified in the ectoderm territory located between the anterior neural plate ectoderm and the future pre-placodal and lateral non-neural ectoderm. At the end of neurulation, NC cells undergo an epithelial-to-mesenchymal transition and migrate to various locations in the developing embryo where they differentiate. While the fine-tuning of NC specification is increasingly being elucidated, many questions remain, including how microRNAs may govern expression of gene programs during these processes. MicroRNAs are short non-coding 20-22 nucleotides-long RNAs which regulate gene expression through post-transcriptional repression. We have identified miR-219 as a candidate regulator of Xenopus NC development. Here, miR-219-dependent molecular pathways were investigated by morpholino knock-down and reveal NC phenotypes. The development of the NC and adjacent ectoderm was evaluated using whole mount in situ hybridization of key markers (pax3, zic1, xhe2, sox10, snai2, sox2), alcian blue cartilage staining, phenotype analysis, RNA sequencing of microdissected dorsal ectoderm and microRNA rescue experiments. While neural induction is mainly unaffected, miR-219 depletion alters gene expression programs associated with neural border development, resulting in loss of NC specification. HighlightsO_LImiR-219 depletion expands the neural border territory and disrupts neural crest specification. C_LIO_LImiR-219 depletion phenotypes are rescued with miRNA mimics. C_LIO_LImiR-219 morphant neural border expansion is rescued by pax3 depletion. C_LIO_LIRNA-seq reveals specific gene program modulation in miR-219 morphant neural crest. C_LIO_LImiR-219 is predicted to directly downregulate the neural gene Hes5.3. C_LI

developmental biology↗

bioRxiv2026

An optimized workflow for spatial transcriptomics across early development in Xenopus

How gene expression patterns change spatially as the embryo transitions from simple to complex structures remains a major developmental biology question. Recently developed imaging-based spatial transcriptomics (ST) enable mapping expression of multiple gene at a single-cell resolution. Although Xenopus is a key model in embryology there is no established ST pipeline, and commercially available techniques face many challenges (sample preparation, probe design, cell segmentation). Furthermore, the highly diverse cell shapes and sizes across developmental stages and between different tissues represent major hurdles to accurately defining cells. Here, we describe an optimized workflow for ST in blastula-to-tailbud-stage frog embryos using Merscope, commercial MERFISH (Multiplexed Error-Robust Fluorescence In Situ Hybridization) originally designed for standard mammalian tissues. With stringent quality control and tailored computational pipelines, we optimize this technology for robust, semi-quantitative profiling of spatial transcriptomic landscapes in non-mammalian embryos. Reliable tissue preservation and cell-segmentation enable high-resolution mapping of gene expression during the development of a complex multi-tissue organization. This versatile strategy applies broadly to various dynamic systems, from embryos of various model organisms to complex and heterogeneous organs in mammals. Summary statementThis Single-cell Spatial Transcriptomics pipeline and reference atlas in Xenopus - a model organism in embryology - overcome technical challenges and resolve dynamic changes in patterning during development.

developmental biology↗

bioRxiv2025

Zebrafish Xenografts Reveal a Context-dependent Roleof PFKFB4 in Melanoma Cell.

Cutaneous melanoma is a highly metastatic cancer in which tumor cell plasticity drives transitions between proliferative and invasive states. The glycolytic regulator PFKFB4 has been implicated in cancer cell motility, but its role in melanoma progression in vivo remains unclear. Using zebrafish larval xenografts, we found that PFKFB4 depletion reduced invasion in MeWo cells without affecting tumor growth, whereas in A375P cells it decreased tumor growth but had no effect on invasion or metastasis. In MeWo, PFKFB4 loss was associated with reduced SNAIL2 expression, while no effect on EMT transcription factors was observed in A375P cells. Rescue experiments indicated that PFKFB4 and SNAIL2 acted independently in regulating Mewo migration in vitro. These findings identify PFKFB4 as a context-dependent regulator of melanoma progression.

cancer biology↗

bioRxiv2025

A novel function for Prdm12 during neural crest migration reveals a link between Wnt and N-cadherin

The delamination of neural crest cells is a critical developmental event shaping the vertebrate head and peripheral nervous system, among other tissues. While the gene regulatory network driving neural crest formation (NC-GRN) has been roughly drafted, there are many fine-tuning mechanisms which require full exploration, especially when a complex cross-talk between several regulators and signaling pathways is involved. We have identified that Prdm12, which encodes a histone methyltransferase highly expressed in the central nervous system and lateral preplacodal ectoderm, is also expressed in the sox10-positive cells located at the lateral front of the premigratory neural crest domain in Xenopus laevis embryos. We show that Prdm12 regulates cranial neural crest emigration, independently of its known enzymatic activity, by regulating non-canonical WNT signaling, which in turn controls N-cadherin membrane localization. Our work elucidates an important function of Prdm12 in the neural crest cells initiating migration and establishes a novel epistatic link between WNT signaling pathways and cell migration in the NC-GRN.

developmental biology↗

bioRxiv2025

MicroRNA miR-196a controls neural crest patterning by repressing immature neural ectoderm programs in Xenopus embryos.

HighlightsmiR-196a promotes Neural Crest development: O_LIRNA sequencing of the developing neural border and neural crest reveals miR-196a-dependent gene programs. C_LIO_LImiR-196a represses early neural plate programs and reduces pluripotency gene expression. C_LIO_LImiR-196a may directly control neural crest gene sox10 in vivo. C_LI Neural crest (NC) cells form a multipotent stem cell population specified during neurulation, which undergo an epithelial-to-mesenchymal transition (EMT) and migrate extensively in the developing embryo, to generate numerous tissues and cell types including the craniofacial skeleton, the peripheral nervous system and pigment cells. The genetic and molecular details of NC specification are governed by a complex, yet still partially understood gene regulatory network (NC-GRN). In particular, the precise function of microRNAs (miRNA) in this network remains poorly characterized. miRNAs are short non-coding 20-22 nucleotides long RNAs, which control gene expression through post-transcriptional repression. Since miRNA-196a is expressed in the developing neural and NC cells of Xenopus laevis embryos, we here investigated miR-196a function in the NC-GRN, by knocking-down its expression using antisense morpholinos. Depletion of miR-196a revealed major NC and craniofacial phenotypes. These defects were preceded by the perturbed expression of key neural, neural border and NC markers such as sox2/3, zic1/3, pax3, sox10 and snail2. Using RNA sequencing of individual neural border and NC explants, we have identified a signature of genes up- and down-regulated by miR-196a and validate these with rescue experiments using a miRNA mimic. Our study identifies miR-196a as a key actor of early patterning in the dorsal ectoderm, balancing the extent of immature neural plate progenitors with NC and placode specification, while also promoting neuron differentiation within the neural plate.

developmental biology↗

bioRxiv2024

A revised single-cell transcriptomic atlas of Xenopus embryo reveals new differentiation dynamics.

This paper introduces an updated single-cell atlas for pivotal developmental stages in Xenopus, encompassing gastrulation, neurulation, and early tailbud. Notably surpassing its predecessor, the new atlas enhances gene mapping, read counts, and gene/cell type nomenclature. Leveraging the latest Xenopus tropicalis genome version, alongside advanced alignment pipelines and machine learning for cell type assignment, this release maintains consistency with previous cell type annotations while rectifying nomenclature issues. Employing an unbiased approach for cell type assignment proves especially apt for embryonic contexts, given the considerable number of non-terminally differentiated cell types. An alternative cell type attribution here adopts a fuzzy, non-deterministic stance, capturing the transient nature of early embryo progenitor cells by presenting an ensemble of types in superposition. The value of the new resource is emphasized through numerous examples, with a focus on previously unexplored germ cell populations where we uncover novel transcription onset features. Offering interactive exploration via a user-friendly web portal and facilitating complete data downloads, this atlas serves as a comprehensive and accessible reference.

developmental biology↗

bioRxiv2022

scEvoNet: a gradient boosting-based method for prediction of cell state evolution

* BackgroundExploring the function or the developmental history of cells in various organisms provides insights into a given cell types core molecular characteristics and putative evolutionary mechanisms. Numerous computational methods now exist for analyzing single-cell data and identifying cell states. These methods mostly rely on the expression of genes considered as markers for a given cell state. Yet, there is a lack of scRNA-seq computational tools to study the evolution of cell states, particularly how cell states change their molecular profiles. This can include novel gene activation or the novel deployment of programs already existing in other cell types, known as co-option. * ResultsHere we present scEvoNet, a Python tool for predicting cell type evolution in crossspecies or cancer-related scRNA-seq datasets. ScEvoNet builds the confusion matrix of cell states and a bipartite network connecting genes and cell states. It allows a user to obtain a set of genes shared by the characteristic signature of two cell states even between distantly-related datasets. These genes can be used as indicators of either evolutionary divergence or co-option occurring during organism or tumor evolution. Our results on cancer and developmental datasets indicate that scEvoNet is a helpful tool for the initial screening of such genes as well as for measuring cell state similarities. * ConclusionsThe scEvoNet package is implemented in Python and is freely available from https://github.com/monsoro/scEvoNet. Utilizing this framework and exploring the continuum of transcriptome states between developmental stages and species will help explain cell state dynamics.

bioinformatics↗

bioRxiv2022

From neural border to migratory stage: A comprehensive single cell roadmap of the timing and regulatory logic driving cranial and vagal neural crest emergence

Neural crest cells exemplify cellular diversification from a multipotent progenitor population. However, the full sequence of molecular choices orchestrating the emergence of neural crest heterogeneity from the embryonic ectoderm remains elusive. Gene-regulatory-networks (GRN) govern early development and cell specification towards definitive neural crest. Here, we combine ultra-dense single cell transcriptomes with machine-learning and large-scale experimental validation to provide a comprehensive GRN underlying neural crest fate diversification from induction to early migration stages in the frog Xenopus tropicalis. During gastrulation, a transient neural border zone state precedes the choice between neural crest and placodes which includes multiple and converging gene programs. Transcription factor connectome and bifurcation analyses demonstrate the early emergence of neural crest fates at the neural plate stage, alongside an unbiased multipotent lineage persisting until after epithelial-mesenchymal transition. We decipher the circuits driving cranial and vagal neural crest formation and provide a broadly applicable strategy for investigating SC transcriptomes in vertebrate GRNs in development, evolution, and disease.

developmental biology↗

bioRxiv2020

The glycolysis regulator PFKFB4 interacts with ICMTand activates RAS/AKT signaling-dependent cell migration in melanoma.

Cell migration is a complex process, tightly regulated during embryonic development and abnormally activated during cancer metastasis. RAS-dependent signaling is a major nexus controlling essential cell parameters including proliferation, survival and migration, utilizing downstream effectors such as the PI3K/AKT signaling pathway. In melanoma, oncogenic mutations frequently enhance RAS, PI3K/AKT or MAP kinase signaling, and trigger other cancer hallmarks among which the activation of metabolism regulators. PFKFB4 is one of these critical regulators of glycolysis and of the Warburg effect. Here however, we explore a novel function of PFKFB4 in melanoma cell migration. We find that PFKFB4 interacts with ICMT, a post-translational modifier of RAS. PFKFB4 promotes ICMT/RAS interaction, controls RAS localization at the plasma membrane, activates AKT signaling and enhances cell migration. We thus provide evidence of a novel and glycolysis-independent function of PFKFB4 in human cancer cells. This unconventional activity links the metabolic regulator PFKFB4 to RAS-AKT signaling and impacts melanoma cell migration. Highlights- PFKFB4, a known regulator of glycolysis, also displays an unconventional role in melanoma cell migration. - PFKFB4 interacts with ICMT and promotes RAS localization at the plasma membrane. - PFKFB4 and ICMT cooperation modulates AKT signaling and controls melanoma cell migration.

cell biology↗

bioRxiv2019

Intracellular enhancement of BMP signaling by LIM-domain protein FHL3 controls spatiotemporal emergence of the neural crest driven by WNT signaling.

How multiple morphogen signals are coordinated in space and time to position key embryonic tissues remains elusive. During neural crest formation, bone morphogenetic protein (BMP), fibroblast growth factor (FGF) and WNT signaling cooperate by acting either on the paraxial mesoderm or directly on the neural border ectoderm, but how each tissue interprets this complex information remains poorly understood. Here we show that Fhl3, a scaffold LIM domain protein of previously unknown developmental function, is essential for neural crest formation by linking BMP and WNT signaling thereby positioning the neural crest-inducing signaling center in the paraxial mesoderm. During gastrulation, Fhl3 promotes Smad phosphorylation and Smad-dependent wnt8 activation specifically in the paraxial mesoderm, thus modifying the respective mesoderm or ectoderm cell response to the extracellular BMP gradient. This ensures neural border ectoderm specification by the underlying mesoderm via non-cell autonomous WNT signaling. During neurulation, neural crest inducers activate fhl3, promoting BMP/Smad-dependent WNT activity required for neural crest specification. Our findings highlight how Fhl3, acting cell-autonomously, ensures a fine spatial, temporal and germ layer-specific coordination of BMP and WNT signaling at several steps of neural crest development.\n\nHighlights- FHL3 is a novel intracellular enhancer of BMP signaling during early development.\n- FHL3 ensures cross-talk between BMP and WNT signaling by Smad1-dependent wnt8 activation in the paraxial mesoderm.\n- FHL3 reiterated function in paraxial mesoderm and in neural border ectoderm is essential for neural crest development at the border of the neural plate.

developmental biology↗

bioRxiv2017

PFKFB4 control of Akt signaling is essential for premigratory and migratory neural crest formation.

Summary statementPFKFB4 controls neural crest final specification and migration by regulation of AKT signaling or glycolysis.\n\nAbstractNeural crest (NC) specification comprises an early phase, initiating immature NC progenitors formation at neural plate stage, and a later phase at neural fold stage, resulting into functional premigratory NC, able to delaminate and migrate. We found that the NC-GRN triggers up-regulation of pfkfb4 (6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 4) during this late specification phase. As shown in previous studies, PFKFB4 controls AKT signaling in gastrulas and glycolysis rate in adult cells. Here, we focus on PFKFB4 function in NC during and after neurulation, using time-controlled or hypomorph depletions in vivo. We find that PFKFB4 is essential both for specification of functional premigratory NC and for its migration. PFKFB4-depleted embryos fail activating n-cadherin and late NC specifiers, exhibit severe migration defects, resulting in craniofacial defects. AKT signaling mediates PFKFB4 function in NC late specification, while both AKT signaling and glycolysis regulate migration. These findings highlight novel and critical roles of PFKFB4 activity in later stages of NC development, wired into the NC-GRN.

developmental biology↗