Biology subjects

Pascual-Mas, P.

Publications and source records attributed to Pascual-Mas, P..

3 recordsLinked to original sources

bioRxiv2025

N2B27 media formulations influence gastruloid development

Gastruloids are 3D aggregates of pluripotent stem cells grown in suspension culture that mimic many aspects of gastrulation and early axial elongation. The N2B27 basal medium in which mouse gastruloids are cultured can either be home-made (HM-N2B27) with materials of known origin, or commercially sourced (NDiff227), where the exact formulation is unknown. In this study we examined whether these formulations resulted in significant differences in gastruloid development. Our results reveal that while both media enable the standard gastruloid elongation, HM-N2B27 results in gastruloids that start the elongation process earlier, have higher number of cells and an increased anterior domain. RNAseq analysis showed significant differences in cell fate specification, with HM-N2B27 gastruloids exhibiting higher expression of spinal cord-related genes, while NDiff227 favours mesodermal differentiation. Furthermore, differential gene enrichment analysis suggests that changes in key signalling pathways underline the differences between HM-N2B27 and NDiff227 gastruloids. These findings highlight the importance of basal media composition for gastruloid development, underscoring the need for careful media selection during in vitro engineering of stem cell-based embryo models. Summary statementIn this work we explored the cellular and molecular sensitiveness of the mouse gastruloid model system to variations in N2B27 media formulations.

developmental biology↗

bioRxiv2025

A temporal coordination between Nodal and Wnt signalling governs the emergence of the mammalian body plan

Nodal and Wnt signalling play an important role in the emergence of the mammalian body plan, primarily by orchestrating gastrulation. While the literature suggests they cooperate to build the primitive streak, their individual contributions remain poorly understood. Using gastruloids, we found that Wnt/{beta}-catenin drives a genetic program characteristic of the late primitive streak, promoting the development of posterior body structures in a time and dose-dependent manner. Conversely, Nodal activates a distinct transcriptional module resembling the early streak. By engineering gastruloids with varying levels of Nodal signalling, we demonstrate that a decreasing temporal gradient of Nodal activity is critical for establishing the anterior body, with higher Nodal levels producing more anterior structures in a concentration-dependent manner. Our findings suggest that Nodal and Wnt act antagonistically, initiating distinct developmental modules within the primitive streak. This antagonism is likely the core mechanism driving the early body plan in mammals.

developmental biology↗

bioRxiv2024

Morphogenetic constrains in the development of gastruloids: implications for mouse gastrulation

Mammalian embryonic size is tightly controlled with checkpoints and compensatory mechanisms correcting size defects. Here, we take advantage of gastruloids, a stem cell embryoid system not subject to most size controls, to study the role of size in emergent properties of mammalian embryogenesis. We report that gastruloids exhibit robust morphology and transcriptional profiles within a size range. However, size affects the dynamics, and, outside a range of robust morphogenesis, the precision of anterior-posterior (AP) axial elongation. Gastruloid axial elongation exhibits active cellular contractility, requires planar cell polarity (PCP), adhesion and cell-cell contact remodelling. Smaller gastruloids initiate elongation earlier, correlated with an earlier Brachyury polarisation. Brachyury expression increases tissue fluidity. Axis formation is regulated by the balance of Brachyury multifoci coalescence and the timing of initiation of the elongation programme. Sizes beyond the robust range can modify relative tissue composition. Very small aggregates have increased neural fate bias, accompanied by a loss of paraxial mesoderm mediated by differences in Nodal signalling activity.

developmental biology↗