Daily Endocrinology Research Analysis
Three mechanistic studies stand out today: liver-innervating vagal sensory neurons were shown to drive hepatic steatosis and anxiety-like behavior in diet-induced obesity; the thyroid hormone–activating enzyme DIO2 was identified as a key mediator of breast cancer–mesenchymal stem cell crosstalk and invasiveness; and environmentally relevant bisphenol A exposure promoted epithelial–mesenchymal transition and dedifferentiation in papillary thyroid cancer.
Summary
Three mechanistic studies stand out today: liver-innervating vagal sensory neurons were shown to drive hepatic steatosis and anxiety-like behavior in diet-induced obesity; the thyroid hormone–activating enzyme DIO2 was identified as a key mediator of breast cancer–mesenchymal stem cell crosstalk and invasiveness; and environmentally relevant bisphenol A exposure promoted epithelial–mesenchymal transition and dedifferentiation in papillary thyroid cancer.
Research Themes
- Liver–brain vagal axis in obesity and MASLD
- Thyroid hormone signaling and tumor microenvironment
- Endocrine disruptors driving thyroid cancer progression
Selected Articles
1. Liver-innervating vagal sensory neurons are indispensable for the development of hepatic steatosis and anxiety-like behavior in diet-induced obese mice.
Selective disruption of liver-innervating vagal sensory neurons in mice increased energy expenditure, prevented diet-induced obesity, attenuated hepatic steatosis, and reduced anxiety-like behavior. Glucose homeostasis improved in both sexes, with male-specific gains in insulin sensitivity, highlighting a bidirectional liver–brain control of metabolic and behavioral phenotypes.
Impact: This study identifies a discrete neural pathway from liver to brain that causally links to steatosis and anxiety in obesity, opening neuromodulatory avenues for MASLD and psychiatric comorbidities.
Clinical Implications: Although preclinical, targeting the liver–brain vagal axis (e.g., selective neuromodulation or peripheral afferent modulation) could complement metabolic therapies for MASLD and address anxiety comorbidity in obesity.
Key Findings
- Ablation of liver-projecting vagal sensory neurons prevented diet-induced obesity by increasing energy expenditure.
- Loss of these neurons limited hepatic steatosis and improved glucose homeostasis; male mice had increased insulin sensitivity.
- Neuronal loss also reduced anxiety-like behavior, implicating the liver–brain axis in metabolic and behavioral regulation.
Methodological Strengths
- Anatomically defined afferent pathway with central (NTS/AP/DMV) and peripheral liver mapping
- Causal manipulation linking neuronal loss to energy expenditure, steatosis, and behavior across sexes
Limitations
- Mouse model findings require validation in humans to confirm translational relevance.
- Molecular signals from liver to brain were not fully delineated.
Future Directions: Define molecular mediators of the liver–brain signal, test neuromodulatory interventions, and conduct human studies to evaluate biomarkers and translational feasibility.
The visceral organ-brain axis, mediated by vagal sensory neurons, is essential for maintaining various physiological functions. Here, we investigate the impact of liver-projecting vagal sensory neurons on energy balance, hepatic steatosis, and anxiety-like behavior in mice under obesogenic conditions. A small subset of vagal sensory neurons innervate the liver and project centrally to the nucleus of the tractus solitarius, area postrema, and dorsal motor nucleus of the vagus, and peripherally to the periportal areas in the liver. The loss of these neurons prevents diet-induced obesity, and these outcomes are associated with increased energy expenditure. Although males and females exhibit improved glucose homeostasis following disruption of liver-projecting vagal sensory neurons, only male mice display increased insulin sensitivity. Furthermore, the loss of liver-projecting vagal sensory neurons limits the progression of hepatic steatosis. Intriguingly, mice lacking liver-innervating vagal sensory neurons also exhibit less anxiety-like behavior compared to control mice. Modulation of the liver-brain axis may aid in designing effective treatments for both psychiatric and metabolic disorders associated with obesity and MAFLD.
2. Thyroid Hormone Activation Regulates the Crosstalk between Breast Cancer and Mesenchymal Stem Cells.
Breast cancer cells increased intracellular thyroid hormone activation via D2, enhancing EMT features and pro-tumorigenic crosstalk with mesenchymal stem cells; genetic D2 inactivation reduced invasiveness and MSC-driven induction. Findings from co-culture and intraductal in vivo modeling nominate D2 as a therapeutic target.
Impact: Identifies a hormone-activating enzyme (D2) as a switch for tumor–stroma dialogue and invasiveness, connecting endocrine signaling to cancer progression with a druggable target.
Clinical Implications: If validated in vivo and clinically, D2 inhibition could attenuate EMT and stromal pro-tumor signaling in hormone-responsive breast cancer; thyroid status and TH activation may warrant consideration in tumor management.
Key Findings
- MCF7 breast cancer cells enhanced intracellular thyroid hormone activation via DIO2, promoting EMT traits.
- DIO2 inactivation reduced invasiveness and dampened responsiveness to mesenchymal stem cell–mediated pro-tumor induction.
- Use of co-culture with primary human MSCs and an intraductal (MIND) in vivo approach supported the role of D2 in tumor–stroma crosstalk.
Methodological Strengths
- Genetic manipulation (DIO2 knockout) with functional phenotyping (growth, migration, invasion, EMT markers)
- Translational modeling using primary human MSCs and intraductal in vivo delivery (MIND)
Limitations
- Findings are preclinical; clinical relevance and safety of D2 inhibition remain untested.
- Evidence reported in an ER+ cell line context; generalizability across breast cancer subtypes is uncertain.
Future Directions: Evaluate pharmacologic D2 inhibitors in orthotopic and metastatic models, define downstream EMT and stromal signaling circuits, and explore biomarker strategies for patient selection.
BACKGROUND: Thyroid Hormones (THs) critically impact human cancer. Although endowed with both tumor-promoting and inhibiting effects in different cancer types, excess of THs has been linked to enhanced tumor growth and progression. Breast cancer depends on the interaction between bulk tumor cells and the surrounding microenvironment in which mesenchymal stem cells (MSCs) exert powerful pro-tumorigenic activities. METHODS: Primary human MSCs from healthy female donors were co-cultured with DIO2 knock out (D2KO) and wild type (WT) MCF7 breast cancer cells to assess cell growth, migration, invasion and the expression of known epithelial-mesenchymal transition (EMT)- and inflammation-related markers. Furthermore, a surgery-free intraductal delivery model, i.e., the Mouse-INtraDuctal (MIND) injection method, was used as a tool for RESULTS: In this study, we uncovered a novel role of THs in regulating the tumor-stroma crosstalk. MCF7 cells enhanced the intracellular activation of THs through the TH-activating enzyme, D2, fostering their EMT properties and the dialogue with MSCs. D2 inactivation reduced the invasiveness of MCF7 cells and their responsiveness to the pro-tumorigenic induction via MSCs, both CONCLUSIONS: Thus, we argue that intracellular activation of THs via D2 is a critical requirement for invasive and metastatic conversion of breast cancer cells, advising the blocking of D2 as a potential therapeutic tool for cancer therapy.
3. Environmental Exposure to Bisphenol A Enhances Invasiveness in Papillary Thyroid Cancer.
Using a 3D papillary thyroid cancer spheroid model, environmentally relevant BPA exposure decreased E-cadherin, increased vimentin, and reduced thyroglobulin secretion, consistent with EMT and dedifferentiation that can enhance invasiveness and compromise radioiodine responsiveness.
Impact: Links a pervasive endocrine disruptor to mechanistic drivers of thyroid cancer aggressiveness using advanced 3D modeling, with public health and therapeutic implications.
Clinical Implications: Supports counseling to minimize BPA exposure, particularly in differentiated thyroid cancer; suggests that environmental exposures may influence tumor differentiation and radioiodine responsiveness.
Key Findings
- BPA at environmentally relevant doses decreased E-cadherin and increased vimentin in PTC spheroids, indicating EMT.
- Thyroglobulin secretion was reduced, suggesting dedifferentiation and potential radioiodine resistance.
- 3D tumor spheroid modeling captured microenvironmental interactions better than 2D cultures for assessing EDC effects.
Methodological Strengths
- Use of a 3D papillary thyroid tumor spheroid model approximating tissue architecture
- Assessment of EMT markers and functional differentiation (thyroglobulin secretion) at environmentally relevant BPA concentrations
Limitations
- In vitro study without in vivo validation; causal links to clinical outcomes are inferential.
- Mechanistic pathways downstream of BPA (e.g., receptor targets) were not fully delineated.
Future Directions: Validate findings in animal models and human tissues, define receptor-mediated pathways, and integrate exposure assessment with clinical phenotyping in thyroid cancer.
Bisphenol A (BPA) is a prevalent environmental contaminant found in plastics and known for its endocrine-disrupting properties, posing risks to both human health and the environment. Despite its widespread presence, the impact of BPA on papillary thyroid cancer (PTC) progression, especially under realistic environmental conditions, is not well understood. This study examined the effects of BPA on PTC using a 3D thyroid papillary tumor spheroid model, which better mimicked the complex interactions within human tissues compared to traditional 2D models. Our findings demonstrated that BPA, at environmentally relevant concentrations, could induce significant changes in PTC cells, including a decrease in E-cadherin expression, an increase in vimentin expression, and reduced thyroglobulin (TG) secretion. These changes suggest that BPA exposure may promote epithelial-mesenchymal transition (EMT), enhance invasiveness, and reduce cell differentiation, potentially complicating treatment, including by increasing resistance to radioiodine therapy. This research highlights BPA's hazardous nature as an environmental contaminant and emphasizes the need for advanced in vitro models, like 3D tumor spheroids, to better assess the risks posed by such chemicals. It provides valuable insights into the environmental implications of BPA and its role in thyroid cancer progression, enhancing our understanding of endocrine-disrupting chemicals.