Biology subjects

Lunn, S.

Publications and source records attributed to Lunn, S..

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↗

bioRxiv2024

Dynamic Wt1 expression in the gastrulation-stage mouse embryo specifies vascular and visceral smooth muscle cell fate independently from mesothelial fate.

1.The Wilms Tumour protein (WT1) was previously linked to the mesothelial and vascular smooth muscle cell (vSMC) lineage in the mouse intestine, with evidence suggesting that intestinal vSMCs arise from the mesothelium. Here, we report that WT1 is already expressed, unexpectedly, during gastrulation, in cells that specify a population of SMC precursor cells in the lateral plate mesoderm (LPM). Tamoxifen-induced genetic lineage tracing of Wt1-expressing cells revealed that vSMC and visceral smooth muscle cells (visSMCs) of the foetal mid-gut, but not mesothelial cells, were labelled after Tamoxifen administration at E7.5 or E8.5. Analysis of single cell RNA sequencing (scRNAseq) datasets of gastrulation-stage mouse embryos and confocal microscopy demonstrated Wt1 expression in epiblast, primitive streak, emerging mesoderm and, from E7.5 onwards, in the LPM. Co-expression of signature smooth muscle markers in Wt1-expressing cells in gastrulation-stage embryos revealed that vSMC and visSMC fate is specified independently from visceral mesothelium formation. Furthermore, Tamoxifen-induced Wt1 knock-out at E7.5 affected vascularisation in the E12.5 intestine. Taken together, our study provides novel insight into the developmental lineage of smooth muscle specified by WT1 expression during gastrulation. Summary StatementThis study provides novel insight into the developmental lineage of smooth muscle cells in the intestine and mesentery, specified by WT1 expression during gastrulation.

developmental biology↗

bioRxiv2021

Using induced pluripotent stem cells to investigate human neuronal phenotypes in 1q21.1 deletion and duplication syndrome.

Copy Number Variation (CNV) at the 1q21.1 locus is associated with a range of neurodevelopmental and psychiatric disorders in humans, including abnormalities in head size and motor deficits. Yet, the functional consequences of these CNVs (both deletion and duplication) on neuronal development remain unknown. To determine the impact of CNV at the 1q21.1 locus on neuronal development, we generated induced pluripotent stem cells from individuals harbouring 1q21.1 deletion or duplication and differentiated them into functional cortical neurons. We show that neurons with 1q21.1 deletion or duplication display reciprocal phenotype with respect to proliferation, differentiation potential, neuronal maturation, synaptic density, and functional activity. Deletion of the 1q21.1 locus was also associated with an increased expression of lower cortical layer markers. This difference was conserved in the mouse model of 1q21.1 deletion, which displayed altered corticogenesis. Importantly, we show that neurons with 1q21.1 deletion and duplication are associated with differential expression of calcium channels and demonstrate that physiological deficits in neurons with 1q21.1 deletion or duplication can be pharmacologically modulated by targeting Ca2+ channel activity. These findings provide biological insight into the neuropathological mechanism underlying 1q21.1 associated brain disorder and indicate a potential target for therapeutic interventions.

neuroscience↗