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Mercury is severely detrimental to organisms and is ubiquitous in both terrestrial and aquatic ecosystems. In the present study, we examined the effects of chronic mercury (Hg) exposure on metamorphosis, body size, thyroid microstructures, liver microstructural and ultrastructural features, and transcript levels of genes associated with lipid metabolism, oxidative stress and thyroid hormones signaling pathways of Chinese toad (Bufo gargarizans) tadpoles. Tadpoles were exposed to mercury concentrations at 0, 6, 12, 18, 24 and 30 µg/L from Gosner stage 26-42 of metamorphic climax. The present results showed that high dose mercury (24 and 30 µg/L) decelerated metamorphosis rate and inhibited body size of B. gargarizans larvae. Histological examinations have clearly exhibited that high mercury concentrations caused thyroid gland and liver damages. Moreover, degeneration and disintegration of hepatocytes, mitochondrial vacuolation, and endoplasmic reticulum breakdown were visible in the ultrastructure of liver after high dose mercury treatment. Furthermore, the larvae exposed to high dose mercury demonstrated a significant decrease in type II iodothyronine deiodinase (Dio2) and thyroid hormone receptor α and β (TRα and TRβ) mRNA levels. Transcript level of superoxide dismutase (SOD) and heat shock protein (HSP) were significantly up regulated in larvae exposed to high dose mercury, while transcript level of phospholipid hydroperoxide glutathione peroxidase (PHGPx) was significantly down regulated. Moreover, exposure to high dose mercury significantly down regulated mRNA expression of carnitine palmitoyltransferase (CPT), sterol carrier protein (SCP), acyl-CoA oxidase (ACOX) and peroxisome proliferator-activated receptor α (PPAPα), but significantly up regulated mRNA expression of fatty acid elongase (FAE), fatty acid synthetase (FAS) and Acetyl CoA Carboxylase (ACC). Therefore, we conclude that high dose mercury induced thyroid function disruption, liver oxidative stress and lipid metabolism disorder by damaging thyroid and liver cell structures and altering the expression levels of relevant genes., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Although a wide range of genetic influences on thyroid-stimulating hormone (TSH) and free thyroxine (fT4) levels have been reported, sex differences in the genetic influences have not been well described., Methods: We assessed TSH and fT4 levels in 2,250 subjects without thyroid peroxidase antibody, with data obtained from the Korea National Health and Nutrition Examination Surveys (KNHANES) conducted from 2013 to 2015. Using variance decomposition methods, the variation of TSH and fT4 levels was divided into genetic and environmental components common to both sexes, and to males and females separately. The genetic correlation between TSH and fT4 levels was also assessed in both sexes, and in males and females separately., Results: Narrow-sense heritability for TSH and fT4 were 54% and 56%, respectively. Sex-specific heritability for TSH levels was significantly higher in females than in males (75% and 41%, respectively; p = 0.037). Heritability for fT4 levels was not significantly different between males and females (62% and 52%, respectively; p = 0.335). TSH and fT4 levels showed a negative genetic correlation in females (ρg = -0.347, p = 0.040) after regressing out the influences of environmental covariates, but this correlation was not present in males (ρg = -0.160, p = 0.391)., Conclusions: The genetic influences on individual TSH levels were more prominent in females than in males. In addition, female-specific pleiotropy between TSH and fT4 might be a clue that this stronger genetic influences in females would mainly affect thyroid function per se, rather than other TSH-related factors that do not primarily trigger the negative feedback loop between TSH and fT4., Competing Interests: The authors have declared that no competing interests exist.

Background: Human adult adipose-derived stem cells (hADSCs) have become the most promising cell source for regenerative medicine. However the prolonged ex vivo expansion periods required to obtain the necessary therapeutic dose promotes progressive senescence, with the concomitant reduction of their therapeutic potential., Aim and Scope: A better understanding of the determinants of hADSC senescence is needed to improve biosafety while preserving therapeutic efficiency. Here, we investigated the association between deregulation of the imprinted DLK1-DIO3 region and replicative senescence in hADSC cultures., Methods: We compared hADSC cultures at short (PS) and prolonged (PL) passages, both in standard and low [O2] (21 and 3%, respectively), in relation to replicative senescence. hADSCs were evaluated for expression alterations in the DLK1-DIO3 region on chromosome 14q32, and particularly in its main miRNA cluster., Results: Comparison of hADSCs cultured at PL or PS surprisingly showed a quite significant fraction (69%) of upregulated miRNAs in PL cultures mapping to the imprinted 14q32 locus, the largest miRNA cluster described in the genome. In agreement, expression of the lncRNA MEG3 (Maternally Expressed 3; Meg3/Gtl2), cultured at 21 and 3% [O2], was also significantly higher in PL than in PS passages. During hADSC replicative senescence the AcK16H4 activating mark was found to be significantly associated with the deregulation of the entire DLK1-DIO3 locus, with a secondary regulatory role for the methylation of DMR regions., Conclusion: A direct relationship between DLK1-DIO3 deregulation and replicative senescence of hADSCs is reported, involving upregulation of a very significant fraction of its largest miRNA cluster (14q32.31), paralleled by the progressive overexpression of the lncRNA MEG3, which plays a central role in the regulation of Dlk1/Dio3 activation status in mice., Competing Interests: The authors have declared that no competing interests exist.

To identify the spectrum and prevalence of thirteen causative genes mutations in congenital hypothyroidism (CH) patients, we collected blood samples and extracted genomic DNA of 106 CH patients, and designed a customized targeted next-generation sequencing panel containing 13 CH-causing genes to detect mutations. A total of 132 mutations were identified in 65.09% of patients (69/106) on the following nine genes: DUOX2, TG, TPO, TSHR, TTF1, TTF2, NKX2-5, PAX8 and GNAS. 69.70% (92/132) mutations related to thyroid dyshormonogenesis genes, including DUOX2 (n = 49), TG (n = 35), and TPO (n = 8). 21.21% (28/132) mutations related to thyroid dysgenesis genes, including TSHR (n = 19), TTF1 (n = 5), TTF2 (n = 1), PAX8 (n = 2), and NKX2-5 (n = 1). 9.09% (12/132) mutations related to GNAS, which was associated with thyrotropin resistance. No mutation of THRA, TSHB, IYD or SLC5A5 was detected. Among 69 mutations detected patients, 41 (59.42%) patients were two or more mutations detected, and mutations of 30 (43.48%) patients related to two or three genes. According to the pathomechanism of the mutant genes, 57.97% CH patients were classified as thyroid dyshormonogenesis. Overall, DUOX2, TG and TSHR mutations were the most common genetic defects in Chinese CH patients, and thyroid dyshormonogenesis could be the first genetic etiology of CH in Chinese. Besides, multiple mutations accounts for a part of genetic pathogenesis.

The mammalian imprinted Dlk1-Dio3 locus produces multiple long non-coding RNAs (lncRNAs) from the maternally inherited allele, including Meg3 (i.e., Gtl2 ) in the mammalian genome. Although this locus has well-characterized functions in stem cell and tumor contexts, its role during neural development is unknown. By profiling cell types at each stage of embryonic stem cell-derived motor neurons (ESC~MNs) that recapitulate spinal cord development, we uncovered that lncRNAs expressed from the Dlk1-Dio3 locus are predominantly and gradually enriched in rostral motor neurons (MNs). Mechanistically, Meg3 and other Dlk1-Dio3 locus-derived lncRNAs facilitate Ezh2/Jarid2 interactions. Loss of these lncRNAs compromises the H3K27me3 landscape, leading to aberrant expression of progenitor and caudal Hox genes in postmitotic MNs. Our data thus illustrate that these lncRNAs in the Dlk1-Dio3 locus, particularly Meg3 , play a critical role in maintaining postmitotic MN cell fate by repressing progenitor genes and they shape MN subtype identity by regulating Hox genes., Competing Interests: YY, WH, YT, YL, EL, HH, YC, TL, MC, JL, SL, JH, JC No competing interests declared, (© 2018, Yen et al.)

This study was conducted to explore the effects of maternal exposure to perfluorooctanoic acid (PFOA) on reproduction and development of male offspring mice. Pregnant mice were given 1, 2.5 or 5 mg/kg BW PFOA daily by gavage during gestation. The results showed that the survival number of offspring mice at weaning was significantly decreased. There were no differences in the testicular index of offspring mice between PFOA exposure groups and non-PFOA group. Maternal exposure to PFOA reduced the level of testosterone in the male offspring mice on PND 21 (p < 0.01) but increased in 1 mg/kg group and decreased in 2.5 and 5 mg/kg groups on PND 70 (p < 0.01). There were different degrees of damage to testis in a dose-dependent manner, and the number of Leydig cells markedly decreased (p < 0.01) in 2.5 and 5 mg/kg PFOA groups on PND 21 and PND 70. The expression of Dlk1-Dio3 imprinted gene cluster showed a decreasing trend, where Glt2, Rian and Dio3 gene expressions were significantly reduced (p < 0.05) on PND 21. Therefore, PFOA exposure during pregnancy reduces the number of survival offspring mice, damages testis, disrupts reproductive hormones and reduces the mRNA expressions of the Dlk1-Dio3 imprinted cluster in testis., (© 2018 Blackwell Verlag GmbH.)

Purpose of Review: To assess new findings and clinical implications of deiodinase gene polymorphism. Deiodinases are enzymes that can activate or inactivate thyroid hormone molecules. Whereas the types 1 and 2 deiodinase (D1 and D2) activate thyroxine (T4) to 3,5,3'-triiodothyronine (T3) via deiodination of T4's outer ring, D1 and D3 inactivate both T4 and T3 and terminate thyroid hormone action via deiodination of T4's inner molecular ring. A number of polymorphisms have been identified in the three deiodinase genes; the most investigated and likely to have clinical relevance is the Thr92 substitution for Ala substitution in DIO2 (Thr92Ala-DIO2). There are a number of reports describing the association between the Thr92Ala-DIO2 polymorphism and clinical syndromes that include hypertension, type 2 diabetes, mental disorders, lung injury, bone turnover, and autoimmune thyroid disease; but these associations have not been reproduced in all population studies., Recent Findings: A new report indicates that carriers of the Thr92Ala-DIO2 polymorphism exhibit lower D2 catalytic activity and localized/systemic hypothyroidism. This could explain why certain groups of levothyroxine-treated hypothyroid patients have improved quality of life when also treated with liothyronine (LT3). Furthermore, Ala92-D2 was abnormally found in the Golgi apparatus, what could constitute a disease mechanism independent of T3 signaling. Indeed, brain samples of Thr92Ala-DIO2 carriers exhibit gene profiles suggestive of brain degenerative disease. In addition, African American carriers of Thr92Ala-DIO2 exhibit an about 30% higher risk of developing Alzheimer's disease., Summary: The finding of deiodinase polymorphisms that can diminish thyroid hormone signaling and/or disrupt normal cellular function opens the door to customized treatment of hypothyroidism. Future studies should explore how the racial background modulates the clinical relevance of the Thr92Ala-DIO2 gene polymorphism.

Objective: Results of the screening of disease causative mutations in congenital hypothyroidism (CH) vary significantly, depending on the sequence strategy, patients' inclusion criteria and bioinformatics. The objective was to study the molecular basis of severe congenital hypothyroidism, using the next generation sequencing (NGS) and the recent guidelines for assessment of sequence variants., Design: 243 patients with CH (TSH levels at neonatal screening or retesting greater than 90 mU/l) and 56 control subjects were included in the study., Methods: A custom NGS panel targeting 12 CH causative genes was used for sequencing. The sequence variants were rated according to American College of Medical Genetics and Genomics (ACMG) guidelines., Results: In total, 48 pathogenic, 7 likely pathogenic and 57 variants of uncertain significance were identified in 92/243 patients (37.9%), while 4 variants of uncertain significance were found in 4/56 control subjects (7.1%). 13.1% (12/92) of the cases showed variants in 'thyroid dysgenesis' (TD) genes: TSHR, n = 6; NKX2-1, n = 2; NKX2-5, n = 1; PAX8, n = 3. The variants in 'dyshormonogenesis' (DH) genes were found in 84.8% (78/92) of cases: TPO, n = 30; DUOX2, n = 24; TG, n = 8; SLC5A5, n = 3; SLC26A4, n = 6; IYD, n = 1. 8 patients showed oligonenic variants. The majority of variants identified in DH genes were monoallelic., Conclusions: In contrast to earlier studies demonstrating the predominance of TD in severe CH, the majority of variants identified in our study were in DH genes. A large proportion of monoallelic variants detected among DH genes suggests that non-mendelian mechanisms may play a role in the development of CH., Competing Interests: The authors have declared that no competing interests exist.

Genomic imprinting is a phenomenon that causes parent-origin-specific monoallelic expression of a small subset of genes, known as imprinted genes, by parentally inherited epigenetic marks. Imprinted genes at the delta-like homolog 1 gene (Dlk1)-type III iodothyronine deiodinase gene (Dio3) imprinted domain, regulated by intergenic differentially methylated region (IG-DMR), are essential for normal development of late embryonic stages. Although the functions of IG-DMR have been reported by generating knockout mice, molecular details of the regulatory mechanisms are not fully understood as the specific sequence(s) of IG-DMR have not been identified. Here, we generated mutant mice by deleting a 216 bp tandem repeated sequence in IG-DMR, which comprised seven repeats of 24 bp motifs, by genome editing technologies. The mutant mice showed that paternal transmission of the deletion allele, but not maternal transmission, induces severe growth retardation and perinatal lethality, possibly due to placental defects. Embryos with a paternally transmitted deletion allele showed biallelic expression of maternally expressed genes and repression of paternally expressed genes. DNA methylation status also showed loss of methylation at IG-DMR and Gtl2-DMR, indicating that the tandem repeat sequence of IG-DMR is one of the functional sequences of IG-DMR, which is required for maintaining DNA methylation imprints of paternal allele at IG-DMR.

Hibernation is an exceptional physiological response to a hostile environment, characterized by a seasonal period of torpor cycles involving dramatic reductions of body temperature and metabolism, and arousal back to normothermia. As the mechanisms regulating hibernation are still poorly understood, here we analysed the expression of genes involved in energy homeostasis, torpor regulation, and daily or seasonal timing using digital droplet PCR in various central and peripheral tissues sampled at different stages of torpor/arousal cycles in the European hamster. During torpor, the hypothalamus exhibited strongly down-regulated gene expression, suggesting that hypothalamic functions were reduced during this period of low metabolic activity. During both torpor and arousal, many structures (notably the brown adipose tissue) exhibited altered expression of deiodinases, potentially leading to reduced tissular triiodothyronine availability. During the arousal phase, all analysed tissues showed increased expression of the core clock genes Per1 and Per2. Overall, our data indicated that the hypothalamus and brown adipose tissue were the tissues most affected during the torpor/arousal cycle, and that clock genes may play critical roles in resetting the body's clocks at the beginning of the active period.

The human thyroid peroxidase (hTPO) is an essential enzyme for thyroid hormone biosynthesis and is expressed in thyroid cells. It is an autoantigen against which antibodies are found in the sera of patients with a number of autoimmune thyroid disorders. Overexpression of hTPO has been achieved using the baculovirus expression vector system (BEVS). However, it is produced largely in an aggregated form in the cell lysate fraction, which increases the complexity of protein extraction. In this study, to achieve improved secretory expression of hTPO via BEVS, a truncated recombinant hTPO protein (hTPOt) was engineered by replacing its original signal peptide (SP) in the N-terminal with five heterologous SPs. Our data showed that the SP from the peptidyl-glycine alpha-amidating monooxygenase (PAM), referred to as SP PAM , significantly promoted the secretion of SP PAM -fused hTPOt (p-hTPOt) in High Five cells. Subsequently, we established an optimized scale-up production procedure for p-hTPOt in a 5-L wave-type bioreactor. The secretory p-hTPOt was purified by immobilized metal-chelating affinity chromatography and ion-exchange chromatography, achieving a protein purity of >95%. Finally, the purified p-hTPOt showed high sensitivity and specificity in reactions with positive or negative human serum samples via the double-antigen sandwich method, suggesting potential applications in hTPO-based research and product development., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Thyroid hormones (THs) regulate vertebrate growth, development, and metabolism. Despite their importance, there is a need for effective detection of TH-disruption by endocrine disrupting chemicals (EDCs). The frog olfactory system substantially remodels during TH-dependent metamorphosis and the objective of the present study is to examine olfactory system gene expression for TH biomarkers that can evaluate the biological effects of complex mixtures such as municipal wastewater. We first examine classic TH-response gene transcripts using reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR) in the olfactory epithelium (OE) and olfactory bulb (OB) of premetamorphic Rana (Lithobates) catesbeiana tadpoles after 48 h exposure to biologically-relevant concentrations of the THs, 3,5,3'-triiodothyronine (T 3 ) and L-thyroxine (T 4 ), or 17-beta estradiol (E 2 ); a hormone that can crosstalk with THs. As the OE was particularly sensitive to THs, further RNA-seq analysis found >30,000 TH-responsive contigs. In contrast, E 2 affected 267 contigs of which only 57 overlapped with THs suggesting that E 2 has limited effect on the OE at this developmental phase. Gene ontology enrichment analyses identified sensory perception and nucleoside diphosphate phosphorylation as the top affected terms for THs and E 2 , respectively. Using classic and additional RNA-seq-derived TH-response gene transcripts, we queried TH-disrupting activity in municipal wastewater effluent from two different treatment systems: anaerobic membrane bioreactor (AnMBR) and membrane enhanced biological phosphorous removal (MEBPR). While we observed physical EDC removal in both systems, some TH disruption activity was retained in the effluents. This work lays an important foundation for linking TH-dependent gene expression with olfactory system function in amphibians., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Introduction: Biological activity of thyroid hormones (TH) is regulated by enzymes known as deiodinases. The most important is represented by the type 2 deiodinase (D2), which is the main T4-activating enzyme, ubiquitous in human tissues and therefore essential in many metabolic processes. A single nucleotide polymorphism (SPN) of D2, known as Thr92Ala (rs225014), has been reported in the general population while other polymorphisms are less frequently described., Areas Covered: Several authors investigated the potential metabolic effect of these polymorphisms in the general population and in specific groups of patients. Thr92Ala polymorphism was mainly studied in patients with autoimmune or surgical hypothyroidism and in patients with physical/psychological disorders that could be related to an overt hypothyroidism. Susceptibility to develop more severe type 2 diabetes or insulin resistance has also been evaluated., Expert Commentary: There is an increasing evidence that the presence of D2 polymorphisms may play a pivotal role in a better definition and customized therapeutic approach of patients with hypothyroidism and/or type 2 diabetes, suggesting that these patients should be screened for D2 polymorphisms. Nevertheless, further research should be performed in order to clarify the association between D2 polymorphisms, metabolic alterations and clinical conditions of the carrier patients.

Status epilepticus (SE) is an abnormally prolonged seizure that results from either a failure of mechanisms that terminate seizures or from initiating mechanisms that inherently lead to prolonged seizures. Here we report that mice experiencing a 3 hours of SE caused by pilocarpine exhibit a rapid increase in expression of type 2 iodothyronine deiodinase gene (Dio2) and a decrease in the expression of type 3 iodothyronine deiodinase gene in hippocampus, amygdala and prefrontal cortex. Type 3 iodothyronine deiodinase in hippocampal sections was seen concentrated in the neuronal nuclei, typical of ischemic injury of the brain. An unbiased analysis of the hippocampal transcriptome of mice undergoing 3 hours of SE revealed a number of genes, including those involved with response to oxidative stress, cellular homeostasis, cell signaling, and mitochondrial structure. In contrast, in mice with targeted disruption of Dio2 in astrocytes (Astro D2KO mouse), the highly induced genes in the hippocampus were related to inflammation, apoptosis, and cell death. We propose that Dio2 induction caused by SE accelerates production of T3 in different areas of the central nervous system and modifies the hippocampal gene expression profile, affecting the balance between adaptive and maladaptive mechanisms.

Methionine-restricted diets (MRD) show an integrated series of beneficial health effects, including improving insulin sensitivity, limiting fat deposition, and decreasing oxidative stress, and inflammation responses. We aimed to explore the systemic responses to a MRD in mice fed with a high fat (HFD) and clarify the possible mechanism. Mice were fed with a control diet (0.86% methionine + 4% fat, CON), HFD (0.86% methionine + 20% fat), or MRD (0.17% methionine + 20% fat) for 22 consecutive weeks. HFD-fed mice showed widespread systemic metabolic disorders and thyroid dysfunction. A MRD significantly increased energy expenditure (e.g. fatty acid oxidation, glycolysis, and tricarboxylic acid cycle metabolism), regulated protein homeostasis, improved gut microbiota functions, prevented thyroid dysfunction, increased plasma thyroxine and triiodothyronine levels, decreased plasma thyroid stimulating hormone levels, increased type 2 deiodinase (DIO2) activity, and up-regulated mRNA and protein expression levels of DIO2 and thyroid hormone receptor α1 in the skeletal muscle. These results suggest that a MRD can improve the metabolic disorders induced by a HFD, and especially regulate energy and protein homeostasis likely through improved thyroid function. Thus, reducing methionine intake (e.g. through a vegan diet) may improve metabolic health in animals and humans.

Deiodinase 2 (DIO2) plays an important role in thyroid hormone metabolism and its regulation. However, molecular mechanism that regulates DIO2 activity remains unclear; only mutaions in selenocysteine insertion sequence binding protein 2 and selenocysteine tranfer RNA (tRNA [Ser]Sec ) are reported to result in decreased DIO2 activity. Two patients with clinical evidence of abnormal thyroid hormone metabolism were identified and found to have TSHR mutations as well as DIO2 T92A single nucleotide polymorphism (SNP). Primary-cultured fibroblasts from one patient present a high level of basal DIO2 enzymatic activity, possibly due to compensation by augmented DIO2 expression. However, this high enzymatic active state yet fails to respond to accelerating TSH. Consequently, TSHR mutations along with DIO2 T92A SNP ("double hit") may lead to a significant reduction in DIO2 activity stimulated by TSH, and thereby may have clinical relevance in a select population of hypothyroidism patients who might benefit from a T3/T4 combination therapy.

Background: Primary congenital hypothyroidism (CH) affects about 1:3000 newborns worldwide and is mainly caused by defects in thyroid gland development (thyroid dysgenesis [TD]) or hormone synthesis. A genetic cause is identified in <10% of TD patients. The aim was to identify novel candidate genes in patients with TD using next-generation sequencing tools., Patient Findings: Whole exome sequencing was used to study two families: a consanguineous Tunisian family (one child with severe thyroid hypoplasia) and a French family (two newborn siblings, with a thyroid in situ that was not enlarged on ultrasound at diagnosis). Variants in candidate genes were filtered according to type of variation, frequency in public and in-house databases, in silico prediction tools, and inheritance mode. Unexpectedly, three different variants of the thyroid peroxidase (TPO) gene were identified. A homozygous missense mutation (c.875C>T, p.S292F) was found in the Tunisian patient with severe thyroid hypoplasia. The two French siblings were compound heterozygotes (c.387delC/c.2578G>A, p.N129Kfs*80/p.G860R) for TPO mutations. All three mutations have been previously described in patients with goitrous CH. In these patients, treatment was initiated immediately after diagnosis, and the effect, if any, of thyrotropin stimulation of these thyroids remains unclear., Conclusions: The first cases are reported of thyroid hypoplasia at diagnosis during the neonatal period in patients with CH and TPO mutations. These cases highlight the importance of screening for TPO mutations not only in goitrous CH, but also in normal or small-size thyroids, and they broaden the clinical spectrum of described phenotypes.

Graves' disease (GD) and Hashimoto's disease (HD) are major autoimmune thyroid diseases (AITDs), and their pathological conditions vary among patients. Type 1 iodothyronine deiodinase (D1) and type 2 iodothyronine deiodinase (D2) convert from thyroxine (T4) to triiodothyronine (T3). However, few findings have been described concerning the association between polymorphisms in D1 and D2 genes and AITD. Therefore, we genotyped D1 rs11206244, D2 rs225014, and rs12885300 polymorphisms in 134 GD patients, including 54 patients with intractable GD and 44 patients with GD in remission and 132 HD patients, including 57 patients with severe HD, 45 patients with mild HD, and 84 healthy controls using PCR-RFLP. In the D2 rs225014 polymorphism, the TT genotype, which was correlated with higher D2 activity, was less frequent in AITD, especially in HD, than in control subjects (P = 0.0032 and 0.0002, respectively). Moreover, they were also less frequent in HD than in GD (P = 0.0199). The TT genotype and T allele were less frequent in severe HD and mild HD than in control subjects (P = 0.0003, 0.0006, 0.0432, and 0.0427, respectively). In conclusion, the low frequency of the TT genotype D2 rs225014 polymorphism was associated with the development of AITD and severity of HD.

Thyroid hormones (THs) influence multiple processes in the developing and adult central nervous system, and their local availability needs to be maintained at levels that are tailored to the requirements of their biological targets. The local complement of TH transporters, deiodinase enzymes, and receptors is critical to ensure specific levels of TH action in neural cells. The type 3 iodothyronine deiodinase (DIO3) inactivates THs and is highly present in the developing and adult brain, where it limits their availability and action. DIO3 deficiency in mice results in a host of neurodevelopmental and behavioral abnormalities, demonstrating the deleterious effects of TH excess, and revealing the critical role of DIO3 in the regulation of TH action in the brain. The fact the Dio3 is an imprinted gene and that its allelic expression pattern varies across brain regions and during development introduces an additional level of control to deliver specific levels of hormone action in the central nervous system (CNS). The sensitive epigenetic nature of the mechanisms controlling the genomic imprinting of Dio3 renders brain TH action particularly susceptible to disruption due to exogenous treatments and environmental exposures, with potential implications for the etiology of human neurodevelopmental disorders.

Human and animal thyroid hormone (TH) plasma carriers (THPC, n=426), cell surface TH transporters (CSTT, n=8,691), and TH nuclear receptors (TR, n=624) share a 49-position long TH-binding motif. Particularly conserved are positions 22-26, where a 5-residue TH-binding motif was originally detected. We extended our research to the 488 sequences of human and animal selenodeiodinases (dio-1, dio-2, dio-3).  In the 10,229 sequences (THPC+CSTT+TR+deiodinases), 15/49 positions are very highly and another 18/49 highly conserved. The very highly conserved 5-residue core TH-binding motif is now W/F/Y, L/I/V/M, I/V/M/L, P, L/V/I/M. Concerning deiodinases, of the 13 conserved residues in their active centers (F121-E214, F128-E228, F139-E233), 11 (dio-1/dio-3) or 10 (dio-2) fall within the 49-position motif. Conserved in the consensus from THPC, CSTT and TR are F129/F136/F147 (position 11). Other matches of deiodinases concerned the nonapolipoprotein THPC: of particular interest, P135/P146 (dio-2/dio-3; position 9), E155/D162/E173 (position 28), S160/S167/S178 (position 33), W163/W170/W178 (position 36). The shared TH-binding domain, which is likely the product of an ancestor gene, may explain why diverse plasma and cell-associated proteins interact with TH.

Objective: Congenital hypothyroidism (CH), the most common neonatal metabolic disorder, is characterized by impaired neurodevelopment. Although several candidate genes have been associated with CH, comprehensive screening of causative genes has been limited., Design and Methods: One hundred ten patients with primary CH were recruited in this study. All exons and exon-intron boundaries of 21 candidate genes for CH were analyzed by next-generation sequencing. And the inheritance pattern of causative genes was analyzed by the study of family pedigrees., Results: Our results showed that 57 patients (51.82%) carried biallelic mutations (containing compound heterozygous mutations and homozygous mutations) in six genes ( DUOX2 , DUOXA2 , DUOXA1 , TG , TPO and TSHR ) involved in thyroid hormone synthesis. Autosomal recessive inheritance of CH caused by mutations in DUOX2 , DUOXA2 , TG and TPO was confirmed by analysis of 22 family pedigrees. Notably, eight mutations in four genes ( FOXE1 , NKX2-1 , PAX8 and HHEX ) that lead to thyroid dysgenesis were identified in eight probands. These mutations were heterozygous in all cases and hypothyroidism was not observed in parents of these probands., Conclusions: Most cases of congenital hypothyroidism in China were caused by thyroid dyshormonogenesis rather than thyroid dysgenesis. This study identified previously reported causative genes for 57/110 Chinese patients and revealed DUOX2 was the most frequently mutated gene in these patients. Our study expanded the mutation spectrum of CH in Chinese patients, which was significantly different from Western countries., (© 2018 The authors.)

Objective: Our aim was to investigate thyroid function alterations attributed to high iodide supplementation in maternal rats and their offspring., Methods: Depending on their iodide intake, the pregnant rats were randomly divided into three groups: normal iodide intake (NI), 10 times high iodide intake (10 HI) and 100 times high iodide intake (100 HI) groups. Iodine concentration in the urine and maternal milk; iodine content and mitochondrial superoxide production; expression of TRα1, TRβ1, NIS and Dio1 in both the thyroid and mammary glands were all measured. The offspring were exposed to different iodide-containing water (NI, 10 HI and 100 HI) from weaning to postnatal day 180 (PN180). Serum thyroid hormone levels were measured in both maternal rats and their offspring., Results: Iodine concentration in the urine and maternal milk, as well as iodine content in the thyroid and mammary glands was significantly increased in both the 10 HI and 100 HI groups (p < .05). In the 100 HI group of maternal rats, low FT3 levels, high FT4, TPOAb and TgAb levels were detected. In addition, an increased mitochondrial superoxide production and decreased expression of TRα1, TRβ1, NIS and Dio1 in the thyroid and mammary glands was found (p < .05). A positive staining of CD4 + that co-localized with TRβ1 in the infiltrated cells within the thyroid follicles was observed. At PN180 in the offspring, the FT3 and FT4 levels showed a significant decrease, while the levels of serum TSH, TPOAb and TgAb were significantly increased in both 10 HI and 100 HI groups (p < .05)., Conclusion: In maternal rats, although normal thyroid function can be maintained following 10 HI, thyroiditis can be induced following 100 HI on lactation days 7, 14, and 21. In the offspring at PN180, hypothyroidism complicated with thyroiditis can occur in both the 10 HI and 100 HI groups., (Copyright © 2018 Elsevier GmbH. All rights reserved.)

Muscle stem cells undergo a dramatic metabolic switch to oxidative phosphorylation during differentiation, which is achieved by massively increased mitochondrial activity. Since expression of the muscle-specific miR-1/133a gene cluster correlates with increased mitochondrial activity during muscle stem cell (MuSC) differentiation, we examined the potential role of miR-1/133a in metabolic maturation of skeletal muscles in mice. We found that miR-1/133a downregulate Mef2A in differentiated myocytes, thereby suppressing the Dlk1-Dio3 gene cluster, which encodes multiple microRNAs inhibiting expression of mitochondrial genes. Loss of miR-1/133a in skeletal muscles or increased Mef2A expression causes continuous high-level expression of the Dlk1-Dio3 gene cluster, compromising mitochondrial function. Failure to terminate the stem cell-like metabolic program characterized by high-level Dlk1-Dio3 gene cluster expression initiates profound changes in muscle physiology, essentially abrogating endurance running. Our results suggest a major role of miR-1/133a in metabolic maturation of skeletal muscles but exclude major functions in muscle development and MuSC maintenance., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Context: A common single nucleotide polymorphism in DIO2, Thr92AlaD2, has been associated with a transcriptome typically found in neurodegenerative diseases in postmortem human brain tissue., Objective: To determine whether Thr92AlaD2 is associated with incident Alzheimer disease (AD)., Design: Population-based study; human brain tissue microarray., Setting: Community-based cohorts from Chicago and northeastern Illinois and religious clergymen from across the United States constituted the primary population. A representative sample of the U.S. population was used for secondary analyses., Participants: 3054 African Americans (AAs) and 9304 European Americans (EAs)., Main Outcome Measure: Incident AD., Results: In the primary population, AAs with Thr92AlaD2 had 1.3 times [95% confidence interval (CI), 1.02 to 1.68; P = 0.048] greater odds of developing AD. AAs from a second population with Thr92AlaD2 showed a trend toward increased odds of dementia (odds ratio, 1.33; 95% CI, 0.99 to 1.78; P = 0.06) and 1.35 times greater odds of developing cognitive impairment not demented (CIND; 95% CI, 1.09 to 1.67; P = 0.006). Meta-analysis showed that AAs with Thr92AlaD2 had 1.3 times increased odds of developing AD/dementia (95% CI, 1.07 to 1.58; P = 0.008). In EAs, no association was found between Thr92AlaD2 and AD, dementia, or CIND. Microarray of AA brain tissue identified transcriptional patterns linked to AD pathogenesis., Conclusions: Thr92AlaD2 was associated with molecular markers known to underlie AD pathogenesis in AAs, translating to an observed phenotype of increased odds of developing AD/dementia in AAs in these populations. Thr92AlaD2 might represent one factor contributing to racial discrepancies in incident AD.

Astrocytes mediate the action of thyroid hormone in the brain on other neural cells through the production of the active hormone triiodothyronine (T3) from its precursor thyroxine. T3 has also many effects on the astrocytes in vivo and in culture, but whether these actions are directly mediated by transcriptional regulation is not clear. In this work, we have analyzed the genomic response to T3 of cultured astrocytes isolated from the postnatal mouse cerebral cortex using RNA sequencing. Cultured astrocytes express relevant genes of thyroid hormone metabolism and action encoding type 2 deiodinase (Dio2), Mct8 transporter (Slc16a2), T3 receptors (Thra1 and Thrb), and nuclear corepressor (Ncor1) and coactivator (Ncoa1). T3 changed the expression of 668 genes (4.5% of expressed genes), of which 117 were responsive to T3 in the presence of cycloheximide. The Wnt and Notch pathways were downregulated at the posttranscriptional level. Comparison with the effect of T3 on astrocyte-enriched genes in mixed cerebrocortical cultures isolated from fetal cortex revealed that the response to T3 is influenced by the degree of astrocyte maturation and that, in agreement with its physiological effects, T3 promotes the transition between the fetal and adult patterns of gene expression.

Innate immune cells, including macrophages, have recently been identified as target cells for thyroid hormone. We hypothesized that optimal intracellular concentrations of the active thyroid hormone triiodothyronine (T3) are essential for proinflammatory macrophage function. T3 is generated intracellularly by type 2 deiodinase (D2) and acts via the nuclear thyroid hormone receptor (TR). In zebrafish embryos, D2 knockdown increased mortality during pneumococcal meningitis. Primary murine D2 knockout macrophages exhibited impaired phagocytosis and partially reduced cytokine response to stimulation with bacterial endotoxin. These effects are presumably due to reduced intracellular T3 availability. Knockdown of the main TR in macrophages, TRα, impaired polarization into proinflammatory macrophages and amplified polarization into immunomodulatory macrophages. Intracellular T3 availability and action appear to play a crucial role in macrophage function. Our data suggest that low intracellular T3 action has an anti-inflammatory effect, possibly due to an effect on macrophage polarization mediated via the TRα. This study provides important insights into the link between the endocrine and innate immune system.

Thyroid hormones (THs, T4 and the transcriptionally active hormone T3) play an essential role in neurodevelopment; however, the mechanisms underlying T3 brain delivery during mice fetal development are not well known. This work has explored the sources of brain T3 during mice fetal development using biochemical, anatomical, and molecular approaches. The findings revealed that during late gestation, a large amount of fetal brain T4 is of maternal origin. Also, in the developing mouse brain, fetal T3 content is regulated through the conversion of T4 into T3 by type-2 deiodinase (D2) activity, which is present from earlier prenatal stages. Additionally, D2 activity was found to be essential to mediate expression of T3-dependent genes in the cerebral cortex, and also necessary to generate the transient cerebral cortex hyperthyroidism present in mice lacking the TH transporter Monocarboxylate transporter 8. Notably, the gene encoding for D2 (Dio2) was mainly expressed at the blood-cerebrospinal fluid barrier (BCSFB). Overall, these data signify that T4 deiodinated by D2 may be the only source of T3 during neocortical development. We therefore propose that D2 activity at the BCSFB converts the T4 transported across the choroid plexus into T3, thus supplying the brain with active hormone to maintain TH homeostasis.

Thyroid hormone (TH) orchestrates amphibian metamorphosis. Thus, this developmental phase is often used to study TH-dependent responses in specific tissues. However, TH signaling appears early in development raising the question of the control of TH availability in specific cell types prior to metamorphosis. TH availability is under strict temporal and tissue-specific control by deiodinases. We examined the expression of the TH-inactivating enzyme, deiodinase type 3 (D3), during early retinal development. To this end we created a Xenopus laevis transgenic line expressing GFP from the Xenopus dio3 promoter region (pdio3) and followed pdio3-GFP expression in pre-metamorphic tadpoles. To validate retinal GFP expression in the transgenic line as a function of dio3 promoter activity, we used in situ hybridization to compare endogenous dio3 expression to reporter-driven GFP activity. Retinal expression of dio3 increased during pre-metamorphosis through stages NF41, 45 and 48. Both sets of results show dio3 to have cell-specific, dynamic expression in the pre-metamorphic retina. At stage NF48, dio3 expression co-localised with markers for photoreceptors, rods, Opsin-S cones and bipolar neurons. In contrast, in post-metamorphic juveniles dio3 expression was reduced and spatially confined to certain photoreceptors and amacrine cells. We compared dio3 expression at stages NF41 and NF48 with TH-dependent transcriptional responses using another transgenic reporter line: THbZIP-GFP and by analyzing the expression of T3-regulated genes in distinct TH availability contexts. At stage NF48, the majority of retinal cells expressing dio3 were negative for T3 signaling. Notably, most ganglion cells were virtually both dio3-free and T3-responsive. The results show that dio3 can reduce TH availability at the cellular scale. Further, a reduction in dio3 expression can trigger fine-tuned T3 action in cell-type specific maturation at the right time, as exemplified here in photoreceptor survival in the pre-metamorphic retina.

Thyroid hormones (THs) are key regulators of growth, development, and metabolism in vertebrates and influence early life development of fish. TH is produced in the thyroid gland (or thyroid follicles) mainly as T4 (thyroxine), which is metabolized to T3 (3,5,3'-triiodothyronine) and T2 (3,5-diiodothyronine) by deiodinase (DIO) enzymes in peripheral tissues. The action of these hormones is mostly exerted by binding to a specific nuclear thyroid hormone receptor (THR). In this study, we i) cloned and characterized thr sequences, ii) investigated the expression pattern of the different subtypes of thrs and dios, and iii) studied how temperature affects the expression of those genes in artificially produced early life history stages of European eel (Anguilla anguilla), reared in different thermal regimes (16, 18, 20 and 22 °C) from hatch until first-feeding. We identified 2 subtypes of thr (thrα and thrβ) with 2 isoforms each (thrαA, thrαB, thrβA, thrβB) and 3 subtypes of deiodinases (dio1, dio2, dio3). All thr genes identified showed high similarity to the closely related Japanese eel (Anguilla japonica). We found that all genes investigated in this study were affected by larval age (in real time or at specific developmental stages), temperature, and/or their interaction. More specifically, the warmer the temperature the earlier the expression response of a specific target gene. In real time, the expression profiles appeared very similar and only shifted with temperature. In developmental time, gene expression of all genes differed across selected developmental stages, such as at hatch, during teeth formation or at first-feeding. Thus, we demonstrate that thrs and dios show sensitivity to temperature and are involved in and during early life development of European eel., (Copyright © 2017 Elsevier Inc. All rights reserved.)

As a feed additive, betaine is widely used in livestock production for its ability to promote growth. Our previous studies had reported that maternal betaine supplementation altered hepatic metabolism in offspring. But it remains unknown whether and how maternal betaine modulates metabolism of thyroid hormones in the offspring chickens by epigenetic modification. In this study, one hundred and twenty Rugao yellow-feathered laying hens were randomly divided into two groups, and were fed basal diet with or without 0.5% betaine supplementation for 28 days. After that, all the hens were artificially inseminated and then four hundreds fertilized eggs were selected. After hatching, the newborn chicks were raised until 56 days old. Betaine fed female chicks showed significantly lower body weight and lower level of biologically active thyroid hormone in plasma compared to control group, which was associated with significantly decrease in expression of type 1 iodothyronine deiodinase (Dio1). Moreover, betaine also changed hepatic expression of betaine-homocysteine -S-methyltransferase (BHMT) and DNA methyltransferase 1 (DNMT1), which may contribute to hypermethylation of the Dio1 promoter. Interestingly, betaine treatments of hens caused none of these effects in male chicks except Dio1 expression. These results indicate that maternal betaine administration effects growth of offspring through differential modification of Dio1 gene methylation and expression in liver and this model of transgenerational effects may help elucidate the mechanisms of maternal effects arise in natural systems., (Copyright © 2018 Elsevier Inc. All rights reserved.)

The Dio2/3 gene is related to the photoperiodic response in mammals and plays an important role in the development of gonadal organs and seasonal breeding. Our previous studies have reported synchronous variations in the gonadal mass and photoperiodical transition around the summer solstice in a wild Brandt's vole population, a species with striking seasonal breeding. To investigate the role of the Dio2/3 gene in the control of seasonal breeding in this species, we cloned and characterized its expression levels by high-throughput Real-Time PCR during the period around the summer solstice. We selected a domesticated strain to ensure similar development of samples. The synchronous variation pattern between the Dio2/3 expression levels and gonadal mass around the summer solstice supports the prediction that the Dio2/3 gene plays an important role in the seasonal transition in this species. We suggest that the observed photoperiod response may be triggered by differences in the day length rather than the absolute daylength in this species. However, the similar Dio2/3 gene expression patterns but inconsistent gonadal mass patterns between the domesticated strain and the wild strain in the samples collected on Sep 8th, an absolute nonbreeding stage in the wild, lead us to speculate that the core function of the Dio2/3 gene should be restricted in response to the photoperiod rather than factors directly regulating gonadal development, and this laboratory strain could be used as an animal model to test the mechanism of environmental adaptation., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Aim: To investigate the association among deiodinases (DIO), organic anion-transporting polypeptide 1C1 (OATP1C1) gene polymorphisms, and thyroid hormones (THs) in patients with acute myocardial infarction (AMI)., Methods: In summary, 290 patients with AMI were evaluated for sociodemographic and clinical characteristics, coronary artery disease (CAD) risk factors, and comorbidities, as well as circulating thyroid-stimulating hormone and TH (triiodothyronine [T3], thyroxine [T4], free T3, free T4, and reverse T3) levels. Ten single nucleotide polymorphisms for thyroid axis related genes: DIO1 (rs11206244-C/T, rs12095080-A/G, rs2235544-A/C), DIO2 (rs225014-T/C, rs225015-G/A), DIO3 (rs945006-T/G), and OATP1C1 (rs10444412-T/C, rs10770704-C/T, rs1515777-A/G, rs974453-G/A) were genotyped., Results: Marginal associations were observed between the DIO1, DIO2, and OATP1C1 gene polymorphisms and almost all analyzed THs (p's < 0.05). After controlling for potential confounders, the OATP1C1 rs1515777-A/G minor allele homozygous genotype (G/G) was associated with a decrease in circulating free T3 and free T3/free T4. In the AMI cohort, associations between: DIO1 rs12095080 and hypertension; DIO2 rs225015 and diabetes mellitus; and the OATP1C1 rs974453 genotype, and AMI type were established., Conclusions: DIO1 and DIO2 gene polymorphisms are mainly associated with T3, free T4, free T3/free T4, and [natural-log transformed (ln)] reverse T3 levels, while the OATP1C1 minor allele homozygous genotype is associated with free T3 and free T3/free T4 in CAD patients after AMI.

Perfluorododecanoic acid (PFDoA), a kind of perfluorinated carboxylic acid (PFCA) with 12 carbon atoms, has an extensive industrial utilization and is widespread in both wildlife and the water environment, and was reported to have the potential to cause a disruption in the thyroid hormone system homeostasis. In this study, zebrafish embryos/larvae were exposed to different concentrations of PFDoA (0, 0.24, 1.2, 6 mg/L) for 96 h post-fertilization (hpf). PFDoA exposure caused obvious growth restriction connected with the reduced thyroid hormones (THs) contents in zebrafish larvae, strengthening the interference effect on the growth of fish larvae. The transcriptional level of genes within the hypothalamic-pituitary-thyroid (HPT) axis was analyzed. The gene expression levels of thyrotropin-releasing hormone (trh) and corticotrophin-releasing hormone (crh) were upregulated upon exposure to 6 mg/L of PFDoA, and iodothyronine deiodinases (dio2) was upregulated in the 1.2 mg/L PFDoA group. The transcription of thyroglobulin (tg) and thyroid receptor (trβ) were significantly downregulated upon exposure to 1.2 mg/L and 6 mg/L of PFDoA. PFDoA could also decrease the levels of sodium/iodide symporter (nis) and transthyretin (ttr) gene expression in a concentration-dependent manner after exposure. A significant decrease in thyroid-stimulating hormoneβ (tshβ), uridinediphosphate-glucuronosyltransferase (ugt1ab) and thyroid receptor (trα) gene expression were observed at 6 mg/L PFDoA exposure. Upregulation and downregulation of iodothyronine deiodinases (dio1) gene expression were observed upon the treatment of 1.2 mg/L and 6 mg/L PFDoA, respectively. All the data demonstrated that gene expression in the HPT axis altered after different PFDoA treatment and the potential mechanisms of the disruption of thyroid status could occur at several steps in the process of synthesis, regulation, and action of thyroid hormones., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Thyroid hormones play a vital role in the human body for growth and differentiation, regulation of energy metabolism, and physiological function. Hypothyroidism is a common endocrine disorder, which generally results from diminished normal circulating concentrations of serum thyroxine (fT4) and triiodothyronine (fT3). The primary choice in hypothyroidism treatment is oral administration of levothyroxine (L-T4), a synthetic T4 hormone, as approximately 100-125 μg/day. Generally, dose adjustment is made by trial and error approach. However, there are several factors which might influence bioavailability of L-T4 treatment. Genetic background could be an important factor in hypothyroid patients as well as age, gender, concurrent medications and patient compliance. The concentration of thyroid hormones in tissue is regulated by both deiodinases enzyme and thyroid hormone transporters. In the present study, it was aimed to evaluate the effects of genetic differences in the proteins and enzymes (DIO1, DIO2, TSHR, THR and UGT) which are efficient in thyroid hormone metabolism and bioavailability of L-T4 in Turkish population. According to our findings, rs225014 and rs225015 variants in DIO2, which catalyses the conversion of thyroxine (pro-hormone) to the active thyroid hormone, were associated with TSH levels. It should be given lower dose to the patients with rs225014 TT and rs225015 GG genotypes in order to provide proper treatment with higher effectivity and lower toxicity.

Sex differences in the expression of iodide transporter SLC5A5 and thyroid peroxidase in thyroid follicular epithelium and thyroid serum profile were assessed in pubertal rats exposed to endocrine disruptor DDT starting from the first postnatal day. It was found that exposure to DDT reduced expression of SLC5A5 in peripheral regions of thyroid lobes in males and in central regions in females. The most pronounced sex differences were observed in thyroid peroxidase expression that remained sensitive to thyroid stimulating hormone regulation in males and lost sensitivity to pituitary stimulation in females after exposure to disruptor, which determines more pronounced hypothyroidism in females.

Excessive fluoride in natural water ecosystem has the potential to detrimentally affect amphibians, but little is known of such effects or underlying mechanisms in Bufo gargarizans embryos. In the present study, the effects of fluoride exposure on B. gargarizans embryos were investigated. First, fluoride teratogenic experiment showed that the 9 days EC 50 of fluoride on B. gargarizans embryos was 177.62 mg/L. Then, we studied the sublethal effects of fluoride on B. gargarizans embryos at control, 0.7, 4.1, 19.6, 41.9, and 62.7 mg/L fluoride concentration. Malformation, growth, and development of embryos were monitored, and type 2 and 3 iodothyronine deiodinase (Dio2 and Dio3), thyroid hormone receptors (TRα and TRβ) mRNA levels were measured. Our results showed the morphological malformations, such as tail curvature (lordosis), edema, cuticularized ciliated cells, and hyperplasia were occurred during fluoride exposure. Growth and development were all inhibited at 19.5, 41.9, and 62.7 mg/L fluoride-treated groups after 9 days' exposure. According to real-time PCR results, exposure to fluoride upregulated Dio3 and TRβ mRNA expression and downregulated Dio2 and TRα mRNA level. All above indicated that excessive fluoride could induce morphology malformations, inhibit embryonic growth and development, and disrupt the normal function of maternal thyroid hormone in B. gargarizans embryos. Environ. Mol. Mutagen. 59:123-133, 2018. © 2017 Wiley Periodicals, Inc., (© 2017 Wiley Periodicals, Inc.)

Congenital hypothyroidism (CH), which results from insufficient thyroid hormone biosynthesis, is one of the most common neonatal endocrine disorders. Thyroid dysgenesis and thyroid dyshormonogenesis are the two causes of CH and either one will lead to deficiencies of enzymes during thyroid hormone biosynthesis and insufficient thyroid hormone biosynthesis. Recently, researchers have performed extensive studies on genetics of CH. This paper reviews genes reported to be associated with CH in China.

Scope: To examine the potential relationship among gene expression markers of adipose tissue browning, gut microbiota, and insulin sensitivity in humans., Methods and Results: Gut microbiota composition and gene markers of browning are analyzed in subcutaneous (SAT) and visceral (VAT) adipose tissue from morbidly obese subjects (n = 34). Plasma acetate is measured through 1 H NMR and insulin sensitivity using euglycemic hyperinsulinemic clamp. Subjects with insulin resistance show an increase in the relative abundance (RA) of the phyla Bacteroidetes and Proteobacteria while RA of Firmicutes is decreased. In all subjects, Firmicutes RA is negatively correlated with HbA 1c and fasting triglycerides, whereas Proteobacteria RA was negatively correlated with insulin sensitivity. Firmicutes RA is positively associated with markers of brown adipocytes (PRDM16, UCP1, and DIO2) in SAT, but not in VAT. Multivariate regression analysis indicates that Firmicutes RA contributes significantly to SAT PRDM16, UCP1, and DIO2 mRNA variance after controlling for age, BMI, HbA 1c , or insulin sensitivity. Interestingly, Firmicutes RA, specifically those bacteria belonging to the Ruminococcaceae family, is positively associated with plasma acetate levels, which are also linked to SAT PRDM16 mRNA and insulin sensitivity., Conclusion: Gut microbiota composition is linked to adipose tissue browning and insulin action in morbidly obese subjects, possibly through circulating acetate., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Neutrophils are essential effector cells of the innate immune system that have recently been recognized as thyroid hormone (TH) target cells. Cellular TH bioavailability is regulated by the deiodinase enzymes, which can activate or inactivate TH. We have previously shown that the TH inactivating enzyme type 3 deiodinase (D3) is present in neutrophils. Furthermore, D3 knockout (D3KO) mice show impaired bacterial killing upon infection. We hypothesized that D3 plays a role in neutrophil function during infection by actively regulating local TH availability. We measured TH concentrations in cerebrospinal fluid (CSF) from patients with bacterial meningitis and controls. Bacterial meningitis resulted in marked changes in CSF TH levels, characterized by a strong increase of thyroxine and reverse-triiodothyronine concentrations. This altered TH profile was consistent with elevated D3 activity in infiltrating neutrophils at the site of infection. D3 knockdown in zebrafish embryos with pneumococcal meningitis resulted in increased mortality and reduced neutrophil infiltration during infection. Finally, stimulated neutrophils from female D3KO mice exhibited impaired NADPH-oxidase activity, an important component of the neutrophil bacterial killing machinery. These consistent findings across experimental models strongly support a critical role for reduced intracellular TH concentrations in neutrophil function during infection, for which the TH inactivating enzyme D3 appears essential., (Copyright © 2018 Endocrine Society.)

Background: Thyroid hormones (TH) are involved in modulation of the immune system and inflammation. TH dysregulation is associated with depressive disorders. The iodothyronine deiodinases (DIOs), the key enzymes for TH synthesis, can be affected and induced by pro-inflammatory cytokines. We aimed to investigate the levels of and correlation between type 2 DIO (DIO2) and interferon-gamma (IFN-ɣ) in patients with recurrent depressive disorders (rDD)., Methods: Data from 91 rDD patients and 105 healthy controls were analyzed. The diagnoses are based on the ICD-10 criteria (F33.0-F33.8). Expression levels of DIO2 and IFN-ɣ were estimated using the method based on the polymerase chain reaction and the enzyme-linked immunosorbent assay (ELISA)., Results: The DIO2 expression on mRNA/protein levels in rDD patients (both female and males) was reduced as compared with the control subjects. No correlation between DIO2 and IFN-ɣ expression was observed., Conclusion: This is the first study to reveal that one may cautiously suggest that DIO2 may be involved in the development and/or progression of rDD. The mechanisms of TH regulation on depression, however, need further investigation., (Copyright © 2017 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier B.V. All rights reserved.)

Purpose: Growth hormone (GH) therapy in adults alters thyroid function, and acromegaly often involves thyroid disease. The present study aimed to elucidate roles and mechanisms of GH in regulating thyroid function., Methods: We performed two retrospective observational studies, which focused on consecutive patients with severe adult GH deficiency who received recombinant human GH (rhGH) therapy (n = 20) and consecutive patients with acromegaly who underwent transsphenoidal surgery (TSS) (n = 25). In both studies, serum free triiodothyronine (fT3), free thyroxine (fT4), and fT3/fT4 ratio were examined before and after the interventions. We subsequently administered GH to four human cell lines (HepG2, TSA201, MCF7, and HTC/C3) in vitro, and examined changes in mRNA levels of iodothyronine deiodinases (D1, D2, and D3)., Results: Median serum fT3 level significantly increased after rhGH therapy from 2.38 to 2.78 pg/mL (p < 0.001), and fT4 decreased from 1.115 to 1.065 ng/dL (p = 0.081). TSS significantly decreased median serum fT3 from 3.03 to 2.53 pg/mL (p < 0.001), and increased fT4 from 1.230 to 1.370 ng/dL (p < 0.001). In vitro, GH significantly increased D2 expression at the mRNA level in HTC/C3 cells (p < 0.01), as well as D2 protein and its activity., Conclusions: GH increased serum fT3 level and decreased serum fT4 level in humans. Our results suggest that its mechanism involves D2 upregulation. Considering this GH effect on thyroid hormone metabolism, data on thyroid function could be useful in the management of GH deficiency and acromegaly.

Thyroid hormone (TH) is present in the systemic circulation and thus should affect all cells similarly in the body. However, tissues have a complex machinery that allows tissue-specific optimization of local TH action that calls for the assessment of TH action in a tissue-specific manner. Here, we report the creation of a TH action indicator (THAI) mouse model to study tissue-specific TH action. The model uses a firefly luciferase reporter readout in the context of an intact transcriptional apparatus and all elements of TH metabolism and transport and signaling. The THAI mouse allows the assessment of the changes of TH signaling in tissue samples or in live animals using bioluminescence, both in hypothyroidism and hyperthyroidism. Beyond pharmacologically manipulated TH levels, the THAI mouse is sufficiently sensitive to detect deiodinase-mediated changes of TH action in the interscapular brown adipose tissue (BAT) that preserves thermal homeostasis during cold stress. The model revealed that in contrast to the cold-induced changes of TH action in the BAT, the TH action in this tissue, at room temperature, is independent of noradrenergic signaling. Our data demonstrate that the THAI mouse can also be used to test TH receptor isoform-specific TH action. Thus, THAI mouse constitutes a unique model to study tissue-specific TH action within a physiological/pathophysiological context and test the performance of thyromimetics. In conclusion, THAI mouse provides an in vivo model to assess a high degree of tissue specificity of TH signaling, allowing alteration of tissue function in health and disease, independently of changes in circulating levels of TH., (Copyright © 2018 Endocrine Society.)

Background: The association between dilated cardiomyopathy (DCM) and low thyroid hormone (TH) levels has been previously described. In these patients abnormal thyroid function is significantly related to impaired left ventricular (LV) function and increased risk of death. Although TH was originally thought to be produced exclusively by the thyroid gland, we recently reported TH biosynthesis in the human ischemic heart., Objectives: Based on these findings, we evaluated whether the genes required for TH production are also altered in patients with DCM., Methods: Twenty-three LV tissue samples were obtained from patients with DCM (n = 13) undergoing heart transplantation and control donors (n = 10), and used for RNA sequencing analysis. The number of LV DCM samples was increased to 23 to determine total T4 and T3 tissue levels by ELISA., Results: We found that all components of TH biosynthesis are expressed in human dilated heart tissue. Expression of genes encoding thyroperoxidase (-2.57-fold, P < 0.05) and dual oxidase 2 (2.64-fold, P < 0.01), the main enzymatic system of TH production, was significantly altered in patients with DCM and significantly associated with LV remodeling parameters. Thyroxine (T4) cardiac tissue levels were significantly increased (P < 0.01), whilst triiodothyronine (T3) levels were significantly diminished (P < 0.05) in the patients., Conclusions: Expression of TH biosynthesis machinery in the heart and total tissue levels of T4 and T3, are altered in patients with DCM. Given the relevance of TH in cardiac pathology, our results provide a basis for new gene-based therapeutic strategies for treating DCM.

Aims: Curcumin can suppress human prostate cancer (HuPCa) cell proliferation and invasion. However, it is not known whether curcumin can inhibit HuPCa stem cell (HuPCaSC) proliferation and invasion., Materials and Methods: We used methyl thiazolyl tetrazolium and Transwell assays to examine the proliferation and invasion of the HuPCaSC lines DU145 and 22Rv1 following curcumin or dimethyl sulfoxide (control) treatment. The microRNA (miRNA) expression levels in the DLK1-DIO3 imprinted genomic region in the cells and in tumor tissues from patients with PCa were examined using microarray and quantitative PCR., Results: The median inhibitory concentration of curcumin for HuPCa cells significantly inhibited HuPCaSC proliferation and invasion in vitro. The miR-770-5p and miR-1247 expression levels in the DLK1-DIO3 imprinted gene cluster were significantly different between the curcumin-treated and control HuPCaSCs. Overexpression of these positive miRNAs significantly increased the inhibition rates of miR-770-5p- and miR-1247-transfected HuPCaSCs compared to the control miR-Mut-transfected HuPCaSCs. Lastly, low-tumor grade PCa tissues had higher miR-770-5p and miR-1247 expression levels than high-grade tumor tissues., Conclusions: Curcumin can suppress HuPCaSC proliferation and invasion in vitro by modulating specific miRNAs in the DLK1-DIO3 imprinted gene cluster.

ype 2 diabetes mellitus (T2DM) remains one of the most challenging global epidemics of the twenty-first century. It is estimated that more than 350 million people worldwide are affected by this metabolic disorder. It has many risk factors. Several studies presume that type II iodothyronine deiodinase polymorphism Thr92Ala (DII-Thr92-Ala, rs225014) is yet another risk factor. The aim of the study was to assess the impact of this polymorphism on parameters of glycid metabolism. Our group consisted of 200 subjects (74 males and 126 females) at average age of 63.85 ± 18.98 without prediabetes, diabetes mellitus or any thyropathy. Blood tests were performed to evaluate glucose metabolism parameters as well as DII-Thr92Ala polymorphism. Our study confirmed the relationship between Ala homozygotes and glycosylated haemoglobin (HbA1c) serum levels (Tab. 2, Ref. 14). Keywords: diabetes mellitus 2, deiodinase II, polymorphism Thr92Ala.

Thyroid hormone (TH) is critical for the maintenance of cellular homeostasis during stress responses, but its role in lung fibrosis is unknown. Here we found that the activity and expression of iodothyronine deiodinase 2 (DIO2), an enzyme that activates TH, were higher in lungs from patients with idiopathic pulmonary fibrosis than in control individuals and were correlated with disease severity. We also found that Dio2-knockout mice exhibited enhanced bleomycin-induced lung fibrosis. Aerosolized TH delivery increased survival and resolved fibrosis in two models of pulmonary fibrosis in mice (intratracheal bleomycin and inducible TGF-β1). Sobetirome, a TH mimetic, also blunted bleomycin-induced lung fibrosis. After bleomycin-induced injury, TH promoted mitochondrial biogenesis, improved mitochondrial bioenergetics and attenuated mitochondria-regulated apoptosis in alveolar epithelial cells both in vivo and in vitro. TH did not blunt fibrosis in Ppargc1a- or Pink1-knockout mice, suggesting dependence on these pathways. We conclude that the antifibrotic properties of TH are associated with protection of alveolar epithelial cells and restoration of mitochondrial function and that TH may thus represent a potential therapy for pulmonary fibrosis.

Leber congenital amaurosis (LCA) is a devastating pediatric retinal degenerative disease, accounting for 20% of blindness in children attending schools for the blind. Mutations in the RPE65 gene, which encodes the retinal pigment epithelium-specific isomerohydrolase RPE65, account for 16% of all LCA cases. Recent findings have linked cone photoreceptor viability to thyroid hormone (TH) signaling. TH signaling regulates cell proliferation, differentiation, and metabolism. At the cellular level, TH action is regulated by the two iodothyronine deiodinases, DIO2 and DIO3. DIO2 converts the prohormone thyroxine (T4) to the bioactive hormone triiodothyronine (T3), and DIO3 inactivates T3 and T4. The present work investigates the effects of overexpression of DIO3 to suppress TH signaling and thereby modulate cone death/survival. Subretinal delivery of AAV5-IRBP/GNAT2-hDIO3 induced robust expression of DIO3 in the mouse retina and significantly reduced the number of TUNEL-positive cells in the cone-dominant LCA model Rpe65 -/- /Nrl -/- mice. Our work shows that suppressing TH signaling by overexpression of DIO3 preserves cones, supporting that suppressing TH signaling locally in the retina may represent a treatment strategy for LCA management.

Human thyroid peroxidase (hTPO) has been secretory expressed in AD293 mammalian cells. cDNA sequence of 'Gluc' (Gaussia luciferase) protein from Gaussia princeps was incorporated at the amino terminal of hTPO gene for secretion of targeted protein outside the mammalian cells. Augmentation of TPO clone in serum free mediums was investigated and a simplified purification procedure of hTPO has been reported here. Purified hTPO was further analyzed by SDS-PAGE and immunoblotting (western blotting). The relative molecular mass of hTPO was found to be 105kDa. This is the first report with respect to cost effective and simplified purification approach to get highest yield and purity of recombinant hTPO., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Thyroid hormones regulate many aspects of brain development and function, and alterations in the levels of thyroid hormone action lead to abnormal anxiety- and depression-like behaviors. A complement of factors in the brain function independently of circulating levels of hormone to strictly controlled local thyroid hormone signaling. A critical factor is the type 3 deiodinase (DIO3), which is located in neurons and protects the brain from excessive thyroid hormone. Here, we examined whether a local increase in brain thyroid hormone action secondary to DIO3 deficiency is of consequence for social behaviors. Although we did not observe alterations in sociability, Dio3-/- mice of both sexes exhibited a significant increase in aggression-related behaviors and mild deficits in olfactory function. In addition, 85% of Dio3-/- dams manifested no pup-retrieval behavior and increased aggression toward the newborns. The abnormal social behaviors of Dio3-/- mice were associated with sexually dimorphic alterations in the physiology of oxytocin (OXT) and arginine vasopressin (AVP), 2 neuropeptides with important roles in determining social interactions. These alterations included low adult serum levels of OXT and AVP, and an abnormal expression of Oxt, Avp and their receptors in the neonatal and adult hypothalamus. Our results demonstrate that DIO3 is essential for normal aggression and maternal behaviors, and indicate that abnormal local regulation of thyroid hormone action in the brain may contribute to the social deficits associated with neurodevelopmental disorders., (© 2017 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.)

The present study examined the effects of chronic cadmium (Cd) exposure on metamorphosis, body size, thyroid gland, and skeletal development of Chinese toad (Bufo gargarizans) tadpoles. Tadpoles were exposed to Cd concentrations at 0, 5, 10, 50, 100, and 500 μg/L from Gosner stages 26 to 46 of completion of metamorphosis. Our results showed that 100 and 500 μg/L of Cd concentrations increased mortality and decelerated metamorphosis rate. In addition, significant body size reduction at Gosner stage 42 was observed at 100 and 500 μg/L of Cd treatments (p < 0.01). Average body length and hind-limb length were significantly decreased in the 500 μg/L of Cd group (p < 0.05) but body mass was not significantly different at Gosner stage 46. Moreover, bone formation was delayed in high Cd concentration treatments (50, 100, and 500 μg/L) at both Gosner stage 42 and 46. Histopathological changes of the thyroid gland showed that follicular cell hyperplasia and malformation were induced by high Cd concentrations (50, 100, and 500 μg/L). Furthermore, real-time polymerase chain reaction analysis suggested that the larvae exposed to high-dose Cd exhibited a significant decrease in deiodinase (Dio2) and thyroid hormone receptor (TRβ) mRNA levels at Gosner stage 42 and 46. Our investigation indicated that high-dose Cd caused metamorphic deceleration, body size reduction, and delayed skeletal development through disrupting the thyroid system in B. gargarizans larvae. Environ Toxicol Chem 2018;37:213-223. © 2017 SETAC., (© 2017 SETAC.)