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Ozga, E.

Publications and source records attributed to Ozga, E..

2 recordsLinked to original sources

Array-CNCC: precise aggregation and arrayed plating facilitate quantitative phenotyping of human cranial neural crest cells and craniofacial disease modelling

Facial development is highly sensitive to genetic and environmental perturbation, with craniofacial malformation associated with over one-third of congenital birth defects. The face arises during an early and largely inaccessible window of embryonic development, with a large contribution from transient and multipotent cranial neural crest cells (CNCCs). Assessment of the molecular and cellular mechanisms driving normal and disordered human facial development therefore relies greatly on the use of in vitro cellular models. Here, we adapted a neurosphere-based CNCC differentiation protocol to facilitate robust quantification of early specification and migration events. Introduction of single-cell aggregation with arrayed plating enabled standardisation of neurosphere size, growth and patterning. Inclusion of fibronectin coating enhanced the efficiency of neurosphere attachment and synchronicity of CNCC migration timing. To demonstrate application of the Array-CNCC method, we developed a strategy for mosaic co-culture, which can facilitate differentiation of wildtype untreated cells directly alongside cells exposed to distinct drug treatments or genetic alterations. Finally, we present a screening approach which we use to test the impact of distinct extracellular matrix components on neurosphere morphology, CNCC migration and gene expression. Together, the Array-CNCC method is highly amenable to quantitative phenotyping and screening approaches, enabling enhanced craniofacial disease modelling with both cellular and molecular readouts.

developmental biology↗

In vitro modelling of anterior primitive streak patterning with hESC reveals the dynamic of WNT and NODAL signalling required to specify notochord progenitors

Notochord progenitors (NotoPs) represent a scarce yet crucial embryonic cell population, playing important roles in embryo patterning and eventually giving rise to the cells that form and maintain intervertebral discs. The mechanisms regulating NotoPs emergence are unclear. This knowledge gap persists due to the inherent complexity of cell fate patterning during gastrulation, particularly within the anterior primitive streak (APS), where NotoPs first arise alongside other important progenitors including neuro-mesodermal and endodermal progenitors. To gain insights into this process, we use micropatterning together with FGF and the WNT pathway activator CHIR9901, to guide the development of human embryonic stem cells into reproducible patterns of APS cell fates. We show that small variations in CHIR9901 dosage dictate the downstream dynamics of endogenous TGFbeta signalling which in turn controls cell fate decisions. We show that sustained NODAL signalling induces endoderm while NODAL inhibition is needed for NMP specification. Furthermore, we unveil a crosstalk between TGFbeta and WNT signaling pathways, wherein TGFbeta inhibition enhances WNT activity. Finally, we demonstrate that the timely inhibition of TGFbeta signalling is imperative for the emergence of NotoPs. Our work elucidates the signalling regimes underpinning NotoPs emergence and provides novel insights into the regulatory mechanisms controlling the balance of APS cell fates during gastrulation.

developmental biology↗