Wnt Modulation Enhances Otic Differentiation by Facilitating the Enucleation Process but Develops Unnecessary Cardiac Structures.

So-Young Chang,Nathaniel T Carpena,Ji-Eun Choi,Min Young Lee,Jae Yun Jung

doi:10.3390/ijms221910306

So-Young Chang, Nathaniel T Carpena + Show 3 more

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https://doi.org/10.3390/ijms221910306

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Abstract

Otic organoids have the potential to resolve current challenges in hearing loss research. The reproduction of the delicate and complex structure of the mammalian cochlea using organoids requires high efficiency and specificity. Recent attempts to strengthen otic organoids have focused on the effects of the Wnt signaling pathway on stem cell differentiation. One important aspect of this is the evaluation of undesirable effects of differentiation after Wnt activation. In the present study, we differentiated mouse embryonic stem cell embryoid bodies (EB) into otic organoids and observed two morphologies with different cell fates. EBs that underwent a core ejection process, or ‘enucleation,’ were similar to previously reported inner ear organoids. Meanwhile, EBs that retained their core demonstrated features characteristic of neural organoids. The application of a Wnt agonist during the maturation phase increased enucleation, as well as otic organoid formation, in turn leading to sensory hair cell-like cell generation. However, with a longer incubation period, Wnt activation also led to EBs with ‘beating’ organoids that exhibited spontaneous movement. This observation emphasizes the necessity of optimizing Wnt enhancement for the differentiation of specific cells, such as those found in the inner ear.

Highlights

With a few modifications [4], we exposed the cells to key factors at specific time points during the differentiation process (Figure 1A, see the Material and Methods section for details)
To generate the embryoid bodies (EB), i.e., the cell clusters/aggregates at the beginning of the differentiation process, the hanging drop technique [12] was used until the EBs reached a certain size, after which they were transferred to differentiation-permissive media
On day 9, the EBs were transferred to maturation media with or without the Wnt agonist CHIR99021 (control and (+) CHIR), where they began to develop small protrusions that may have included otic organoids

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. As a recent development in stem cell technology, organoids are in vitro structures similar in morphology and function to certain body organs. They have been used for a variety of purposes, such as screening for drug discovery and uncovering the pathogenesis of certain diseases. For these applications, the organoids of specific target organs must be highly specific and replicable

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