TREM2 is thyroid hormone regulated making the TREM2 pathway druggable with ligands for thyroid hormone receptor

Novel Thyroid Hormone Receptor-β Agonist TG68 Exerts Anti-Inflammatory, Lipid-Lowering and Anxiolytic Effects in a High-Fat Diet (HFD) Mouse Model of Obesity

Recent advances in drug development allowed for the identification of THRβ-selective thyromimetic TG68 as a very promising lipid lowering and anti-amyloid agent. In the current study, we first investigated the neuroprotective effects of TG68 on in vitro human models of neuroinflammation and β-amyloid neurotoxicity in order to expand our knowledge of the therapeutic potential of this novel thyromimetic. Subsequently, we examined metabolic and inflammatory profiles, along with cognitive changes, using a high-fat diet (HFD) mouse model of obesity. Our data demonstrated that TG68 was able to prevent either LPS/TNFα-induced inflammatory response or β-amyloid-induced cytotoxicity in human microglial (HMC3) cells. Next, we demonstrated that in HFD-fed mice, treatment with TG68 (10 mg/kg/day; 2 weeks) significantly reduced anxiety-like behavior in stretch-attend posture (SAP) tests while producing a 12% BW loss and a significant decrease in blood glucose and lipid levels. Notably, these data highlight a close relationship between improved serum metabolic parameters and a reduction of anxious behavior. Moreover, TG68 administration was observed to efficiently counteract HFD-altered central and peripheral expressions in mice with selected biomarkers of metabolic dysfunction, inflammation, and neurotoxicity, revealing promising neuroprotective effects. In conclusion, our work provides preliminary evidence that TG68 may represent a novel therapeutic opportunity for the treatment of interlinked diseases such as obesity and neurodegenerative diseases.

TREM2 as a Therapeutic Target in Atherosclerosis

Atherosclerosis is driven by the expansion of cholesterol-loaded foamy macrophages in the arterial intima. Single-cell RNA sequencing has recently revealed the transcriptional landscape of macrophages in these atherosclerotic plaques and uncovered a population of foamy cell-like myeloid cells expressing triggering receptor expressed on myeloid cells-2 (TREM2)-TREM2hi macrophages. Fundamental research has brought essential insight into the significance of TREM2 for foam macrophage survival and atherosclerosis progression, making TREM2 as a therapeutic target in atherosclerosis possible. This review retraces TREM2's winding route from pure knowledge to therapeutic interventions, as well as the potential feasibility of its clinical application for atherosclerosis.

An adoptive cell therapy with TREM2-overexpressing macrophages mitigates the transition from acute kidney injury to chronic kidney disease

BACKGROUND

Macrophages have been shown to contribute to renal injury and fibrosis as well as repair. Recently, Triggering Receptor Expressed on Myeloid Cells 2 (TREM2)-positive macrophages have been shown to play important roles in regulating tissue inflammation and repair. However, it remains unclear whether they can mitigate the transition from acute kidney injury to chronic kidney disease (the AKI-CKD transition).

METHODS

The AKI-CKD transition was generated by unilateral ischaemia-reperfusion injury (UIRI) in wild-type (WT) and Trem2 knockout mice. F4/80 magnetic beads were used to isolate renal macrophages. Flow cytometry was used to determine the levels of TREM2 and CD11b levels. Quantitative reverse transcription polymerase chain reaction (qRT-PCR), Western blotting and histological staining were performed to determine the expression of cytokines and fibrotic markers. RNA-seq was used to investigate transcriptomic changes between WT and Trem2 knockout bone marrow-derived macrophages (BMDMs). TREM2-overexpressing macrophages were generated using lentivirus and transferred intravenously to UIRI mice.

RESULTS

TREM2 macrophages exhibited a strong renal protective effect on the AKI-CKD transition. Genetic deletion of Trem2 resulted in increased renal inflammation and exacerbated renal injury and fibrosis in UIRI mice. Interestingly, we found that hypoxia could increase TREM2 expression in macrophages via HIF-1α. Upregulated TREM2 expression enhanced macrophage phagocytosis and suppressed the expression of pro-inflammatory cytokines, resulting in lower levels of apoptosis and fibrosis in tubular epithelial cells. Using RNA-seq analysis, we showed that the regulatory effects of TREM2 were orchestrated by the PI3K-AKT pathway. Pharmacological regulation of the PI3K-AKT pathway could modulate the macrophage-mediated inflammation and phagocytosis. In addition, an adoptive cell therapy using TREM2-overexpressing macrophages effectively reduced the immune cell infiltration, renal injury and fibrosis in UIRI mice.

CONCLUSION

Our study not only provides valuable mechanistic insights into the role of Trem2 in the AKI-CKD transition but also offers a new avenue for TREM2-overexpressing macrophage-based adoptive cell therapy to treat kidney diseases.

KEY POINTS

TREM2 knockout worsens kidney injury and accelerates AKI-CKD transition. TREM2 is upregulated by hypoxia via HIF1α in AKI-CKD transition. An adoptive cell therapy using TREM2-overexpressing macrophages reduces kidney inflammation and fibrosis.

Thyroid hormone receptor-β analogues for the treatment of metabolic dysfunction-associated steatohepatitis (MASH)

The association between suboptimal thyroid function ((sub)clinical hypothyroidism or low-normal thyroid function) and the metabolic syndrome and MASLD (metabolic dysfunction-associated steatotic liver disease) has been clearly established. Furthermore, in MASLD, intracellular thyroid hormone concentrations are low and the activation of the thyroid hormone receptor (THR) is reduced. Administration of thyroid hormone has been shown to reduce liver triglycerides by stimulating fatty acid disposal through lipophagy and beta-oxidation, and to lower LDL-cholesterol. As thyroid hormone exerts its effects in many different organs, including the heart and bone, several drug candidates have been developed as selective thyromimetics for the THR-β nuclear receptor with potent and liver-targeted activity. Importantly, these compounds have reduced affinity for the THR-α nuclear receptor and tissue distribution profiles that differ from endogenous thyroid hormones, thereby reducing unwanted cardiovascular side effects. The most advanced compound, resmetirom, is an oral drug that demonstrated, in a large phase III trial in patients with MASH (metabolic dysfunction-associated steatohepatitis), the ability to reduce liver fat, decrease aminotransferase levels and improve atherogenic dyslipidaemia with a good tolerability profile. This translated into histological improvement that led to accelerated approval of this drug for active fibrotic steatohepatitis, a milestone achievement as a first MASH drug.

Association between hypothyroidism and obstructive sleep apnea: a bidirectional Mendelian randomization study combined with the geo database

Background

The causal relationship between hypothyroidism and obstructive sleep apnea (OSA) remains controversial. Therefore, our research used a bidirectional Mendelian randomization (MR) method in an attempt to determine the causal relationship between hypothyroidism and OSA.

Methods

From the publicly accessible genome-wide association analysis (GWAS) summary database, we obtained single nucleotide polymorphism (SNPs) data pertaining to hypothyroidism and OSA. Inverse variance weighting (IVW) was the principal method of analysis utilized, with validation also conducted via weighted median, MR-Egger, simple model, and weighted model approaches. To further evaluate the robustness of the results, heterogeneity testing, pleiotropy testing, and the "leave-one-out" sensitivity analysis were performed. Differentially expressed genes (DEGs) from the OSA dataset (GSE135917) and hypothyroidism dataset (GSE176153) derived from the Gene Expression Omnibus (GEO) database were screened using the "limma" package. The "clusterProfiler" and "GO plot" packages were used for further enrichment analysis in order to validate the findings of the MR study. The Cytoscape software was utilized to build a protein-protein interaction (PPI) network of DEGs and to screen for hub genes.

Results

The MR analysis showed that genetically predicted hypothyroidism was associated with an increased risk of OSA [IVW odds ratio (OR) = 1.734; 95% confidence interval (CI) = 1.073-2.801; p = 0.025]. The trend of the outcomes of the other approaches is consistent with the trend of the IVW outcome. However, the reverse MR analysis suggested no evidence for the causal effect of OSA on hypothyroidism (IVW OR = 1.002, 95% CI: 0.996-1.009, p = 0.454). The robustness of the results was confirmed by the sensitivity analysis. Bioinformatics analysis revealed that there were DEGs that hypothyroidism and OSA have in common.

Conclusion

Our findings suggested that hypothyroidism may increase the risk of OSA, while the effect of OSA on hypothyroidism was not found in this MR study. Thus, patients with hypothyroidism should be enhanced with screening for OSA for early diagnosis and appropriate treatment.

Thyroid Hormone and Alzheimer Disease: Bridging Epidemiology to Mechanism

The identification of critical factors that can worsen the mechanisms contributing to the pathophysiology of Alzheimer disease is of paramount importance. Thyroid hormones (TH) fit this criterion. Epidemiological studies have identified an association between altered circulating TH levels and Alzheimer disease. The study of human and animal models indicates that TH can affect all the main cellular, molecular, and genetic mechanisms known as hallmarks of Alzheimer disease. This is true not only for the excessive production in the brain of protein aggregates leading to amyloid plaques and neurofibrillary tangles but also for the clearance of these molecules from the brain parenchyma via the blood-brain barrier and for the escalated process of neuroinflammation-and even for the effects of carrying Alzheimer-associated genetic variants. Suboptimal TH levels result in a greater accumulation of protein aggregates in the brain. The direct TH regulation of critical genes involved in amyloid beta production and clearance is remarkable, affecting the expression of multiple genes, including APP (related to amyloid beta production), APOE, LRP1, TREM2, AQP4, and ABCB1 (related to amyloid beta clearance). TH also affects microglia by increasing their migration and function and directly regulating the immunosuppressor gene CD73, impacting the immune response of these cells. Studies aiming to understand the mechanisms that could explain how changes in TH levels can contribute to the brain alterations seen in patients with Alzheimer disease are ongoing. These studies have potential implications for the management of patients with Alzheimer disease and ultimately can contribute to devising new interventions for these conditions.

Current understanding on TREM-2 molecular biology and physiopathological functions

Triggering receptor expressed on myeloid cells 2 (TREM-2), a glycosylated receptor belonging to the immunoglobin superfamily and especially expressed in the myeloid cell lineage, is frequently explained as a reminiscent receptor for both adaptive and innate immunity regulation. TREM-2 is also acknowledged to influence NK cell differentiation via the PI3K and PLCγ signaling pathways, as well as the partial activation or direct inhibition of T cells. Additionally, TREM-2 overexpression is substantially linked to cell-specific functions, such as enhanced phagocytosis, reduced toll-like receptor (TLR)-mediated inflammatory cytokine production, increased transcription of anti-inflammatory cytokines, and reshaped T cell function. Whereas TREM-2-deficient cells exhibit diminished phagocytic function and enhanced proinflammatory cytokines production, proceeding to inflammatory injuries and an immunosuppressive environment for disease progression. Despite the growing literature supporting TREM-2+ cells in various diseases, such as neurodegenerative disorders and cancer, substantial facets of TREM-2-mediated signaling remain inadequately understood relevant to pathophysiology conditions. In this direction, herein, we have summarized the current knowledge on TREM-2 biology and cell-specific TREM-2 expression, particularly in the modulation of pivotal TREM-2-dependent functions under physiopathological conditions. Furthermore, molecular regulation and generic biological relevance of TREM-2 are also discussed, which might provide an alternative approach for preventing or reducing TREM-2-associated deformities. At last, we discussed the TREM-2 function in supporting an immunosuppressive cancer environment and as a potential drug target for cancer immunotherapy. Hence, summarized knowledge of TREM-2 might provide a window to overcome challenges in clinically effective therapies for TREM-2-induced diseases in humans.

Artificial intelligence for drug discovery and development in Alzheimer's disease

The complex molecular mechanism and pathophysiology of Alzheimer's disease (AD) limits the development of effective therapeutics or prevention strategies. Artificial Intelligence (AI)-guided drug discovery combined with genetics/multi-omics (genomics, epigenomics, transcriptomics, proteomics, and metabolomics) analysis contributes to the understanding of the pathophysiology and precision medicine of the disease, including AD and AD-related dementia. In this review, we summarize the AI-driven methodologies for AD-agnostic drug discovery and development, including de novo drug design, virtual screening, and prediction of drug-target interactions, all of which have shown potentials. In particular, AI-based drug repurposing emerges as a compelling strategy to identify new indications for existing drugs for AD. We provide several emerging AD targets from human genetics and multi-omics findings and highlight recent AI-based technologies and their applications in drug discovery using AD as a prototypical example. In closing, we discuss future challenges and directions in AI-based drug discovery for AD and other neurodegenerative diseases.

TREM-2: friend or foe in infectious diseases?

The triggering receptor expressed on myeloid cells-2 (TREM-2) is an immune receptor expressed on immune and non-immune cells, more frequently investigated in neurodegenerative disorders and considered a marker for microglia activation. In infectious diseases, the receptor was initially believed to be an anti-inflammatory molecule, opposing the inflammation triggered by TREM-1. Currently, TREM-2 is associated with different aspects in response to infectious stimuli, including the induction of bacterial phagocytosis and clearance, containment of exacerbated pro-inflammatory responses, induction of M2 differentiation and activation of Th1 lymphocytes, besides of neurological damage after viral infection. Here, we present and discuss results published in the last two decades regarding the expression, activation and functions of TREM-2 during the course of bacterial, viral, fungal and parasitic infections. A surprisingly plasticity was observed regarding the roles of the receptor in the aforementioned contexts, which largely varied according to the cell/organ and pathogen type, besides influencing disease outcome. Therefore, our review aimed to critically overview the role of TREM-2 in infectious diseases, highlighting its potential to be used as a clinical biomarker or therapeutic target.

Alzheimer risk-increasing TREM2 variant causes aberrant cortical synapse density and promotes network hyperexcitability in mouse models

The R47H variant of triggering receptor expressed on myeloid cells 2 (TREM2) increases the risk of Alzheimer's disease (AD). To investigate potential mechanisms, we analyzed knockin mice expressing human TREM2-R47H from one mutant mouse Trem2 allele. TREM2-R47H mice showed increased seizure activity in response to an acute excitotoxin challenge, compared to wildtype controls or knockin mice expressing the common variant of human TREM2. TREM2-R47H also increased spontaneous thalamocortical epileptiform activity in App knockin mice expressing amyloid precursor proteins bearing autosomal dominant AD mutations and a humanized amyloid-β sequence. In mice with or without such App modifications, TREM2-R47H increased the density of putative synapses in cortical regions without amyloid plaques. TREM2-R47H did not affect synaptic density in hippocampal regions with or without plaques. We conclude that TREM2-R47H increases AD-related network hyperexcitability and that it may do so, at least in part, by causing an imbalance in synaptic densities across brain regions.

Comparing RNA-sequencing datasets from astrocytes, oligodendrocytes, and microglia in multiple sclerosis identifies novel dysregulated genes relevant to inflammation and myelination

Central nervous system (CNS) inflammation is a key factor in multiple sclerosis (MS). Invasion of peripheral immune cells into the CNS resulting from an unknown signal or combination of signals results in activation of resident immune cells and the hallmark feature of the disease: demyelinating lesions. These lesion sites are an amalgam of reactive peripheral and central immune cells, astrocytes, damaged and dying oligodendrocytes, and injured neurons and axons. Sustained inflammation affects cells directly located within the lesion site and further abnormalities are apparent diffusely throughout normal-appearing white matter and grey matter. It is only relatively recently, using animal models, new tissue sampling techniques, and next-generation sequencing, that molecular changes occurring in CNS resident cells have been broadly captured. Advances in cell isolation through Fluorescence Activated Cell Sorting (FACS) and laser-capture microdissection together with the emergence of single-cell sequencing have enabled researchers to investigate changes in gene expression in astrocytes, microglia, and oligodendrocytes derived from animal models of MS as well as from primary patient tissue. The contribution of some dysregulated pathways has been followed up in individual studies; however, corroborating results often go unreported between sequencing studies. To this end, we have consolidated results from numerous RNA-sequencing studies to identify and review novel patterns of differentially regulated genes and pathways occurring within CNS glial cells in MS. This article is categorized under: Neurological Diseases > Molecular and Cellular Physiology.

Thyroid hormone-dependent oligodendroglial cell lineage genomic and non-genomic signaling through integrin receptors

Multiple sclerosis (MS) is a heterogeneous autoimmune disease whereby the pathological sequelae evolve from oligodendrocytes (OLs) within the central nervous system and are targeted by the immune system, which causes widespread white matter pathology and results in neuronal dysfunction and neurological impairment. The progression of this disease is facilitated by a failure in remyelination following chronic demyelination. One mediator of remyelination is thyroid hormone (TH), whose reliance on monocarboxylate transporter 8 (MCT8) was recently defined. MCT8 facilitates the entry of THs into oligodendrocyte progenitor cell (OPC) and pre-myelinating oligodendrocytes (pre-OLs). Patients with MS may exhibit downregulated MCT8 near inflammatory lesions, which emphasizes an inhibition of TH signaling and subsequent downstream targeted pathways such as phosphoinositide 3-kinase (PI3K)-Akt. However, the role of the closely related mammalian target of rapamycin (mTOR) in pre-OLs during neuroinflammation may also be central to the remyelination process and is governed by various growth promoting signals. Recent research indicates that this may be reliant on TH-dependent signaling through β1-integrins. This review identifies genomic and non-genomic signaling that is regulated through mTOR in TH-responsive pre-OLs and mature OLs in mouse models of MS. This review critiques data that implicates non-genomic Akt and mTOR signaling in response to TH-dependent integrin receptor activation in pre-OLs. We have also examined whether this can drive remyelination in the context of neuroinflammation and associated sequelae. Importantly, we outline how novel therapeutic small molecules are being designed to target integrin receptors on oligodendroglial lineage cells and whether these are viable therapeutic options for future use in clinical trials for MS.

Impaired learning and memory generated by hyperthyroidism is rescued by restoration of AMPA and NMDA receptors function

Hyperthyroidism has been identified as a risk factor for cognitive disorders. The hippocampus is a key brain region associated with cognitive function, among which excitatory synapse transmission plays an important role in the process of learning and memory. However, the mechanism by which hyperthyroidism leads to cognitive dysfunction through a synaptic mechanism remains unknown. We investigated the synaptic mechanisms in the effects of hyperthyroidism in an animal model that involved repeated injection of triiodothyronine (T3). These mice displayed impaired learning and memory in the Novel object recognition test, Y-maze test, and Morris Water Maze test, as well as elevated anxiety in the elevated plus maze. Mature dendritic spines in the hippocampal CA1 region of hyperthyroid mice were significantly decreased, accompanied by decreased level of AMPA- and NMDA-type glutamate receptors in the hippocampus. In primary cultured hippocampal neurons, levels of AMPA- and NMDA-type glutamate receptors also decreased and whole-cell patch-clamp recording revealed that excitatory synaptic function was obviously attenuated after T3 treatment. Notably, pharmacological activation of AMPAR or NMDAR by intraperitoneal injection of CX546, an AMPAR agonist, or NMDA, an NMDAR agonist can restore excitatory synaptic function and corrected impaired learning and memory deficit in hyperthyroid mice. Together, our findings uncovered a previously unrecognized AMPAR and NMDAR-dependent mechanism involved in regulating hippocampal excitatory synaptic transmission and learning and memory disorders in hyperthyroidism.

Microglial TYROBP/DAP12 in Alzheimer's disease: Transduction of physiological and pathological signals across TREM2

TYROBP (also known as DAP12 or KARAP) is a transmembrane adaptor protein initially described as a receptor-activating subunit component of natural killer (NK) cells. TYROBP is expressed in numerous cell types, including peripheral blood monocytes, macrophages, dendritic cells, and osteoclasts, but a key point of recent interest is related to the critical role played by TYROBP in the function of many receptors expressed on the plasma membrane of microglia. TYROBP is the downstream adaptor and putative signaling partner for several receptors implicated in Alzheimer's disease (AD), including SIRP1β, CD33, CR3, and TREM2. TYROBP has received much of its current notoriety because of its importance in brain homeostasis by signal transduction across those receptors. In this review, we provide an overview of evidence indicating that the biology of TYROBP extends beyond its interaction with these four ligand-binding ectodomain-intramembranous domain molecules. In addition to reviewing the structure and localization of TYROBP, we discuss our recent progress using mouse models of either cerebral amyloidosis or tauopathy that were engineered to be TYROBP-deficient or TYROBP-overexpressing. Remarkably, constitutively TYROBP-deficient mice provided a model of genetic resilience to either of the defining proteinopathies of AD. Learning behavior and synaptic electrophysiological function were preserved at normal physiological levels even in the face of robust cerebral amyloidosis (in APP/PSEN1;Tyrobp-/- mice) or tauopathy (in MAPTP301S;Tyrobp-/- mice). A fundamental underpinning of the functional synaptic dysfunction associated with each proteotype was an accumulation of complement C1q. TYROBP deficiency prevented C1q accumulation associated with either proteinopathy. Based on these data, we speculate that TYROBP plays a key role in the microglial sensome and the emergence of the disease-associated microglia (DAM) phenotype. TYROBP may also play a key role in the loss of markers of synaptic integrity (e.g., synaptophysin-like immunoreactivity) that has long been held to be the feature of human AD molecular neuropathology that most closely correlates with concurrent clinical cognitive function.

Thyroid Hormone Changes in the Northern Area of Tianjin during the COVID-19 Pandemic

PURPOSE

This study aimed to determine whether and how stress-induced thyroid hormone changes occur during the COVID-19 pandemic in the northern area of Tianjin.

METHODS

This study comprised two groups of study subjects in Tianjin: before (2019) and during (2020) the COVID-19 outbreak. Subjects were included if they had FT3, FT4, and TSH concentrations and thyroid TPOAb or TgAb information available. People who were pregnant, were lactating, or had mental illness were excluded. We used propensity score matching to form a cohort in which patients had similar baseline characteristics, and their anxiety level was measured by the Hamilton Anxiety Rating Scale (HAMA).

RESULTS

Among the 1395 eligible people, 224 in Group A and 224 in Group B had similar propensity scores and were included in the analyses. The detection rate of abnormal thyroid function was decreased in pandemic Group B (69.2% vs. 93.3%, χ 2 = 42.725, p < 0.01), especially for hypothyroidism (14.29% vs. 35.71%, χ 2 = 27.429, p < 0.01) and isolated thyroid-related antibodies (25.89% vs. 38.39%, χ 2 = 8.023, p < 0.01). The level of FT4 (z = -2.821, p < 0.01) and HAMA score (7.63 ± 2.07 vs. 5.40 ± 1.65, t = 16.873, p < 0.01) went up in Group B; however, TSH (z = -5.238, p < 0.01), FT3 (z = -3.089, p=0.002), TgAb (z = -11.814, p < 0.01), and TPOAb (z = -9.299, p < 0.01) were lower, and HAMA was positive with FT3 (r = 0.208, p < 0.01) and FT4 (r = 0.247, p < 0.01).

CONCLUSION

People in the northern area of Tianjin during the COVID-19 outbreak were at an increased risk of higher FT4, lower FT3, and lower TSH. The HAMA scores increased in emergency situations and were positively correlated with the levels of FT3 and FT4.

Some natural hypomethylating agents in food, water and environment are against distribution and risks of COVID-19 pandemic: Results of a big-data research

OBJECTIVE

This study analyzes the effects of lifestyle, nutrition, and diets on the status and risks of apparent (symptomatic) COVID-19 infection in Iranian families.

MATERIALS AND METHODS

A relatively extensive questionnaire survey was conducted on more than 20,000 Iranian families (residing in more than 1000 different urban and rural areas in the Islamic Republic of Iran) to collect the big data of COVID-19 and develop a lifestyle dataset. The collected big data included the records of lifestyle effects (e.g. nutrition, water consumption resources, physical exercise, smoking, age, gender, health and disease factors, etc.) on the status of COVID-19 infection in families (i.e. residents of homes). Therefore, an online self-reported questionnaire was used in this retrospective observational study to analyze the effects of lifestyle factors on the COVID-19 risks. The data collection process spanned from May 10, 2020 to March 19, 2021 by selecting 132 samples from more than 40 different social network communities.

RESULTS

The research results revealed that food and water sources, which contain some natural hypomethylating agents, mitigated the risks of apparent (symptomatic) COVID-19 infection. Furthermore, the computations on billions of permutations of nutrition conditions and dietary regime items, based on the data collected from people's diets and infection status, showed that there were many dietary conditions alleviating the risks of apparent (symptomatic) COVID-19 infection by 90%. However, some other diets tripled the infection risk.

CONCLUSION

Some natural hypomethylating agents in food, water, and environmental resources are against the spread and risks of COVID-19.

Thyroid Hormone Receptor Beta as Tumor Suppressor: Untapped Potential in Treatment and Diagnostics in Solid Tumors

There is compelling evidence that the nuclear receptor TRβ, a member of the thyroid hormone receptor (TR) family, is a tumor suppressor in thyroid, breast, and other solid tumors. Cell-based and animal studies reveal that the liganded TRβ induces apoptosis, reduces an aggressive phenotype, decreases stem cell populations, and slows tumor growth through modulation of a complex interplay of transcriptional networks. TRβ-driven tumor suppressive transcriptomic signatures include repression of known drivers of proliferation such as PI3K/Akt pathway, activation of novel signaling such as JAK1/STAT1, and metabolic reprogramming in both thyroid and breast cancers. The presence of TRβ is also correlated with a positive prognosis and response to therapeutics in BRCA+ and triple-negative breast cancers, respectively. Ligand activation of TRβ enhances sensitivity to chemotherapeutics. TRβ co-regulators and bromodomain-containing chromatin remodeling proteins are emergent therapeutic targets. This review considers TRβ as a potential biomolecular diagnostic and therapeutic target.