Development of Microphysiological Models of the Thyroid

Introduction: The thyroid produces hormones that play a critical role in metabolism and development. This gland is highly vascularized and is primarily composed of spherical follicles formed by thyroid follicular cells (TFCs). The thyroid can experience both autoimmunity and cancer, making it an immunologically interesting organ. Microphysiological models of the thyroid can provide a platform through which the thyroid immune microenvironment can be studied, and potential therapeutics can be evaluated.

Materials and

Methods: We cultured two thyroid follicular cell lines (TFC1 and TFC2) in spheroid plates and two different extracellular matrix gels (Gel1 and Gel2). Spheroid/organoid morphology and growth under different culture conditions were evaluated in imaging experiments. In further experiments, cell behavior will be observed in co-cultures of thyroid organoids and spheroids with other cell types.

Results, Conclusions, and Discussions:

Results:
We observed spheroid formation when TFCs were grown in spheroid plates, and organoid formation when TFCs were grown on extracellular matrix gels. Of the two TFCs tested, TFC2 formed more spherical and uniform organoids/spheroids, while those generated with TFC1 had a more distinctly fluffy appearance.

Conclusions:
Thyroid follicular cells can form follicle-like structures when grown in spheroid plates or on extracellular matrix gels. Gel composition and cell type can directly affect organoid behavior. Cell plating density and culture time determine spheroid size, enabling precise tuning of properties.

Discussion:
In vitro models such as spheroids and organoids can be used to study the thyroid gland and especially thyroid follicles. Experiments evaluating the effects of culture conditions, including co-cultures with other cell types, on spheroid/organoid gene expression and morphological characteristics are in progress. Further data on the integration of these organoids and spheroids in more complex in vitro models will be presented.

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