SCREENED: A Multistage Model of Thyroid Gland Function for Screening Endocrine-Disrupting Chemicals in a Biologically Sex-Specific Manner

Abstract

Endocrine disruptors (EDs) are chemicals that contribute to health problems by interfering with the physiological production and target effects of hormones, with proven impacts on a number of endocrine systems including the thyroid gland. Exposure to EDs has also been associated with impairment of the reproductive system and incidence in occurrence of obesity, type 2 diabetes, and cardiovascular diseases during ageing. SCREENED aims at developing in vitro assays based on rodent and human thyroid cells organized in three different three-dimensional (3D) constructs. Due to different levels of anatomical complexity, each of these constructs has the potential to increasingly mimic the structure and function of the native thyroid gland, ultimately achieving relevant features of its 3D organization including: (1) a 3D organoid based on stem cell-derived thyrocytes, (2) a 3D organoid based on a decellularized thyroid lobe stromal matrix repopulated with stem cell-derived thyrocytes, and (3) a bioprinted organoid based on stem cell-derived thyrocytes able to mimic the spatial and geometrical features of a native thyroid gland. These 3D constructs will be hosted in a modular microbioreactor equipped with innovative sensing technology and enabling precise control of cell culture conditions. New superparamagnetic biocompatible and biomimetic particles will be used to produce “magnetic cells” to support precise spatiotemporal homing of the cells in the 3D decellularized and bioprinted constructs. Finally, these 3D constructs will be used to screen the effect of EDs on the thyroid function in a unique biological sex-specific manner. Their performance will be assessed individually, in comparison with each other, and against in vivo studies. The resulting 3D assays are expected to yield responses to low doses of different EDs, with sensitivity and specificity higher than that of classical 2D in vitro assays and animal models. Supporting the “Adverse Outcome Pathway” concept, proteogenomic analysis and biological computational modelling of the underlying mode of action of the tested EDs will be pursued to gain a mechanistic understanding of the chain of events from exposure to adverse toxic effects on thyroid function. For future uptake, SCREENED will engage discussion with relevant stakeholder groups, including regulatory bodies and industry, to ensure that the assays will fit with purposes of ED safety assessment. In this project review, we will briefly discuss the current state of the art in cellular assays of EDs and how our project aims at further advancing the field of cellular assays for EDs interfering with the thyroid gland.

Transplantable human thyroid organoids generated from embryonic stem cells to rescue hypothyroidism

“…This model opens a new window on the morphogenetic processes and gene regulatory networks associated with thyroid development. In addition, it could be used as a model to study the role of newly identified variants in causing congenital hypothyroidism and to test the toxic effects of many compounds to which we are constantly exposed in our daily life, in particular endocrine disruptors 76 , an emerging challenge in thyroid pathophysiology. Although this model still needs improvement before it becomes therapeutically applicable, it provides a proof of concept that generating autologous human thyroid tissue to maintain TH levels is within reach.…”

Emerging concepts and opportunities for endocrine disruptor screening of the non-EATS modalities

“…For these chemicals, the GOLIATH, OBERON and EDCMET consortia aim to develop assays targeting the main nuclear receptors and tissues involved in metabolic diseases ( Audouze et al, 2020 ; Küblbeck et al, 2020 ; Legler et al, 2020 ). Although few test guidelines exist for thyroid disruption (EATS modality), no validated in vitro alternatives exist and the ATHENA, ERGO and SCREENED projects are establishing methods on different modes of thyroid disruption using advanced cell cultures and alternative animal models ( Holbech et al, 2020 ; Kortenkamp et al, 2020 ; Moroni et al, 2020 ). The ENDpoiNTs project will aid in the understanding of the mode of action (MoA) of EDCs on the neuroendocrine axis by establishing new methodologies ( Lupu et al, 2020 ), whereas the FREIA project addresses the lack of test methods for female reproduction ( Duursen et al, 2020 ).…”

Endocrine Disrupting Chemicals’ Effects in Children: What We Know and What We Need to Learn?

“…EDCs can widely affect this process and thyroid disruption can occur at any level of the HPT axis including thyroid hormones synthesis, release, transport, metabolism, and action on target tissues [ 2 , 245 , 246 ]. Clinical studies are still few and controversial and three projects within the EURION [ 28 ] are focusing on improvement of testing strategies for thyroid hormone EDCs: ATHENA [ 247 ], ERGO [ 248 ], and SCREENED [ 249 ].…”