A post-irradiation-induced replication stress promotes RET proto-oncogene breakage.

Objective: Ionizing radiation generates genomic instability by promoting the accumulation of chromosomal rearrangements. The oncogenic translocation RET/PTC1 is present in more than 70% of radiation-induced thyroid cancers. Both RET and CCDC6, the genes implicated in RET/PTC1, are found within common fragile sites - chromosomal regions prone to DNA breakage during slight replication stress. Given that irradiated cells become more susceptible to genomic destabilization due to the accumulation of replication-stress-related double-strand breaks (DSBs), we explored whether RET and CCDC6 exhibit DNA breakage under replicative stress several days post-irradiation of thyroid cells. Methods: We analyzed the dynamic of DNA replication in human thyroid epithelial cells (HThy-ori-3.1) 4 days post a 5-Gy exposure using molecular DNA combing. The DNA replication schedule was evaluated through replication-timing experiments. We implemented a ChIP-qPCR assay to determine whether the RET and CCDC6 genes break following irradiation. Results: Our study indicates that replicative stress, occurring several days post-irradiation in thyroid cells, primarily causes DSBs in the RET gene. We discovered that both the RET and CCDC6 genes undergo late replication in thyroid cells. However, only RET's replication rate is notably delayed after irradiation. Conclusion: The findings suggest that post-irradiation in the RET gene causes a breakage in the replication fork, which could potentially invade another genomic area, including CCDC6. As a result, this could greatly contribute to the high prevalence of chromosomal RET/PTC rearrangements seen in patients exposed to external radiation.

Impact of Bariatric Surgery on Thyroid Morphology and Thyroid Function.

INTRODUCTION: Few studies have evaluated the impact of bariatric surgery (BS) on thyroid function and morphology, and how it correlates to inflammatory and metabolic markers. We aimed to evaluate all those parameters together. METHODS: A longitudinal study included 70 patients with severe obesity. The bariatric group (BG) enrolled 40 patients who underwent BS, and the control group (CG) enrolled 30 patients who did not undergo BS. Both were submitted (pre- and 2nd-year) to thyroid ultrasound and laboratory analyses to determine the levels of thyroid hormones, inflammatory, and metabolic markers. RESULTS: Thyroid volume (TV) decreased after BS (-1.5 cm3), differing significantly from the CG (+0.6 cm3; p = 0.003). ΔTV was independently and positively correlated with ΔHOMA-IR (0.41 (0.11/7.16) p = 0.007) and ΔIL6 (0.02 (0.01/0.3) p = 0.016). A nonsignificant correlation between ΔTV and ΔBMI was detected (0.38 (-0.01/0.09) p = 0.152). We also observed a negative correlation between ΔTV and ΔTSH (-2.03 (-2.87/-1.19) p = 0.000) and ΔT3/T4 ratio (-0.06 (-0.09/-0.02) p = 0.001). TSH had a nonsignificant reduction with BS (-0.3872 vs. -0.2483 p = 0.128). The conversion of T4 to T3 had a significant increase after BS, as demonstrated by the T3/T4 ratio (+5.16 p = 0.01). Despite an increase in the prevalence of thyroid nodules in the BG, it was not statistically significant (p = 0.340). CONCLUSION: BS was associated with a reduction in TV and a nonstatistically significant reduction in TSH. The variations in TV were related to the metabolic markers and inflammatory changes. An increase in the conversion of T4 to T3 with BS was detected, possibly related to inflammatory improvement.

Case Report: Composite pheochromocytoma with ganglioneuroma component: A report of three cases.

Composite pheochromocytoma (CP) is a very rare tumor originating from neural crest cells, predominantly composed of pheochromocytoma (PCC), a chromaffin cell tumor arising in adrenal medulla, and ganglioneuroma, a tumor derived from autonomic ganglion cells of the nervous system. Moreover, CP may be present in the hereditary syndromes of which pheochromocytoma is part. Literature offers scarce data on this subject, and particularly about its biological behavior, clinical evolution, and molecular profile. We report the phenotype and outcome of three cases of CP (PCC and ganglioneuroma components), followed up at the Endocrine Service of the Clementino Fraga Filho University Hospital, Federal University of Rio de Janeiro, UFRJ, Rio de Janeiro, Brazil. Two nonsyndromic patients (cases 1 and 2) were negative to germline mutations in genes VHL, SDHB, SDHC, SDHD, SDHAF2, TMEM127, and MAX, while the third case (case 3) had clinical diagnosis of neurofibromatosis syndrome. Cases 1, 2, and 3 were diagnosed at 29, 39, and 47 years old, respectively, and were followed up for 3, 17, and 9 years without no CP recurrence. All cases had apparent symptoms of catecholaminergic excess secreted by PCC. Ganglioneuroma, the neurogenic component present in all three cases, had a percentage representation ranging from 5% to 15%. Tumors were unilateral and large, measuring 7.0 cm × 6.0 cm × 6.0 cm, 6.0 cm × 4.0 cm × 3.2 cm, and 7.5 cm × 6.0 cm × 4.5 cm, respectively. All cases underwent adrenalectomy with no recurrence, metastasis, or development of contralateral tumor during follow-up. Genetic testing has been scarcely offered to CP cases. However, a similar frequency of genetic background is found when compared with classic PCC, mainly by the overrepresentation of NF1 cases in the CP subset. By literature review, we identified a notorious increase in cases reported with CP in the last decade, especially in the last 3 years, indicating a recent improvement in the diagnosis of this rare disorder in clinical practice.

Transcriptional profile in rat muscle: down-regulation networks in acute strenuous exercise.

BACKGROUND: Physical exercise is a health promotion factor regulating gene expression and causing changes in phenotype, varying according to exercise type and intensity. Acute strenuous exercise in sedentary individuals appears to induce different transcriptional networks in response to stress caused by exercise. The objective of this research was to investigate the transcriptional profile of strenuous experimental exercise. METHODOLOGY: RNA-Seq was performed with Rattus norvegicus soleus muscle, submitted to strenuous physical exercise on a treadmill with an initial velocity of 0.5 km/h and increments of 0.2 km/h at every 3 min until animal exhaustion. Twenty four hours post-physical exercise, RNA-seq protocols were performed with coverage of 30 million reads per sample, 100 pb read length, paired-end, with a list of counts totaling 12816 genes. RESULTS: Eighty differentially expressed genes (61 down-regulated and 19 up-regulated) were obtained. Reactome and KEGG database searches revealed the most significant pathways, for down-regulated gene set, were: PI3K-Akt signaling pathway, RAF-MAP kinase, P2Y receptors and Signaling by Erbb2. Results suggest PI3K-AKT pathway inactivation by Hbegf, Fgf1 and Fgr3 receptor regulation, leading to inhibition of cell proliferation and increased apoptosis. Cell signaling transcription networks were found in transcriptome. Results suggest some metabolic pathways which indicate the conditioning situation of strenuous exercise induced genes encoding apoptotic and autophagy factors, indicating cellular stress. CONCLUSION: Down-regulated networks showed cell transduction and signaling pathways, with possible inhibition of cellular proliferation and cell degeneration. These findings reveal transitory and dynamic process in cell signaling transcription networks in skeletal muscle after acute strenuous exercise.

Exercise-Stimulated ROS Sensitive Signaling Pathways in Skeletal Muscle.

Physical exercise represents a major challenge to whole-body homeostasis, provoking acute and adaptative responses at the cellular and systemic levels. Different sources of reactive oxygen species (ROS) have been described in skeletal muscle (e.g., NADPH oxidases, xanthine oxidase, and mitochondria) and are closely related to the physiological changes induced by physical exercise through the modulation of several signaling pathways. Many signaling pathways that are regulated by exercise-induced ROS generation, such as adenosine monophosphate-activated protein kinase (AMPK), mitogen activated protein kinase (MAPK), nuclear respiratory factor2 (NRF2), and PGC-1α are involved in skeletal muscle responses to physical exercise, such as increased glucose uptake, mitochondriogenesis, and hypertrophy, among others. Most of these adaptations are blunted by antioxidants, revealing the crucial role played by ROS during and after physical exercise. When ROS generation is either insufficient or exacerbated, ROS-mediated signaling is disrupted, as well as physical exercise adaptations. Thus, an understanding the limit between "ROS that can promote beneficial effects" and "ROS that can promote harmful effects" is a challenging question in exercise biology. The identification of new mediators that cause reductive stress and thereby disrupt exercise-stimulated ROS signaling is a trending on this topic and are covered in this current review.

The Effect of Acute Aerobic Exercise on Redox Homeostasis and Mitochondrial Function of Rat White Adipose Tissue.

Physical exercise is characterized by an increase in physical and metabolic demand in face of physical stress. It is reported that a single exercise session induces physiological responses through redox signaling to increase cellular function and energy support in diverse organs. However, little is known about the effect of a single bout of exercise on the redox homeostasis and cytoprotective gene expression of white adipose tissue (WAT). Thus, we aimed at evaluating the effects of acute aerobic exercise on WAT redox homeostasis, mitochondrial metabolism, and cytoprotective genic response. Male Wistar rats were submitted to a single moderate-high running session (treadmill) and were divided into five groups: control (CTRL, without exercise), and euthanized immediately (0 h), 30 min, 1 hour, or 2 hours after the end of the exercise session. NADPH oxidase activity was higher in 0 h and 30 min groups when compared to CTRL group. Extramitochondrial ROS production was higher in 0 h group in comparison to CTRL and 2 h groups. Mitochondrial respiration in phosphorylative state increased in 0 h group when compared to CTRL, 30 min, 1, and 2 h groups. On the other hand, mitochondrial ATP production was lower in 0 h in comparison to 30 min group, increasing in 1 and 2 h groups when compared to CTRL and 0 h groups. CAT activity was lower in all exercised groups when compared to CTRL. Regarding oxidative stress biomarkers, we observed a decrease in reduced thiol content in 0 h group compared to CTRL and 2 h groups, and higher levels of protein carbonylation in 0 and 30 min groups in comparison to the other groups. The levels returned to basal condition in 2 h group. Furthermore, aerobic exercise increased NRF2, GPX2, HMOX1, SOD1, and CAT mRNA levels. Taken together, our results suggest that one session of aerobic exercise can induce a transient prooxidative state in WAT, followed by an increase in antioxidant and cytoprotective gene expression.

Analysis of morbid obese women aerobic potential / Análisis del potencial aeróbico de obesas mórbidas

Abstract Introduction: nowadays, with the increase of world obesity and the numbers of morbidly obese people, a concerning public health problem that is difficult to solve rises up. Objective: to analyse the physiological responses after the 6-minute walk tests and maximum stress test in the arm cycle ergometer in morbidly obese pre-bariatric surgery women. Methods: fifteen level III obesity women aged 35.6 ± 6.6 years took part in this experiment. Firstly, they went through an anamnesis and body composition analysis; secondly, they were submitted to a 6-minute walk test and a maximum stress test in arm cycle ergometer on alternate days. Results: patients were able to perform the maximum stress test and showed better aerobic potentials in the arm cycle ergometer than in the 6-minute walk test. No significant differences were found between SPO2 and diastolic blood pressure between the moments of rest and after the tests, neither in the systolic blood pressure after the 6-minute walk test and the values of rest and post 5 minutes in the maximum stress test. The main differences found were between the maximum systolic blood pressure in the cycle ergometer test and the other moments and the heart rate after the tests and the heart rate at rest. Conclusion: the maximum stress test in arm cycle ergometer is a safe method that allows greater requirement and control applied to the heart system than in the 6-minute walk test. In addition, it allows the development of a more individualized aerobic training and prescription of aerobic physical exercise program.

Resumen Introducción: Actualmente, con el aumento de la obesidad en el mundo y del número de obesos mórbidos se evidencia un problema de salud pública de difícil resolución. Objetivo: analizar las respuestas fisiológicas tras las pruebas de caminata de 6 minutos y de esfuerzo máximo en cicloergómetro de brazos en obesas mórbidas precirugía bariátrica. Métodos: se evaluaron 15 mujeres con obesidad grado III con edad media de 35,6 ± 6,6 años, las cuales participaron inicialmente de una anamnesis con el análisis de la composición corporal y posteriormente participaron en días alternos de la prueba de 6 minutos de caminata y del mismo, prueba de esfuerzo máximo en cicloergómetro de brazos. Resultados: las pacientes lograron realizar la prueba de esfuerzo máximo y demostraron mejores potenciales aeróbicos en el cicloergómetro de brazos que en la prueba de caminata. No se encontraron diferencias significativas entre la SPO2 y la presión arterial diastólica entre los momentos de reposo y después de las pruebas y también en la presión arterial sistólica posterior a la prueba de caminata y los valores de reposo y después de 5 minutos en la prueba de esfuerzo máximo. Las principales diferencias se observaron entre la presión arterial sistólica máxima en la prueba en cicloergómetro y los otros momentos y en la frecuencia cardiaca después de las pruebas y las frecuencias cardiacas en reposo. Conclusión: la prueba de esfuerzo máximo en cicloergómetro de brazos es un método seguro que posibilita mayor exigencia y control aplicado al sistema cardíaco que en la prueba de caminata. Adicionalmente, permite un programa de entrenamiento y una prescripción del ejercicio físico aeróbico más individualizados.

Redox Signaling in Widespread Health Benefits of Exercise.

Significance: Exercise-induced reactive oxygen species (ROS) production activates multiple intracellular signaling pathways through genomic and nongenomic mechanisms that are responsible for the beneficial effects of exercise in muscle. Beyond the positive effect of exercise on skeletal muscle cells, other tissues such as white and brown adipose, liver, central nervous system, endothelial, heart, and endocrine organ tissues are also responsive to exercise. Recent Advances: Crosstalk between different cells is essential to achieve homeostasis and to promote the benefits of exercise through paracrine or endocrine signaling. This crosstalk can be mediated by different effectors that include the secretion of metabolites of muscle contraction, myokines, and exosomes. During the past 20 years, it has been demonstrated that contracting muscle cells produce and secrete different classes of myokines, which functionally link muscle with nearly all other cell types. Critical Issues: The redox signaling behind this exercise-induced crosstalk is now being decoded. Many of these widespread beneficial effects of exercise require not only a complex ROS-dependent intramuscular signaling cascade but simultaneously, an integrated network with many remote tissues. Future Directions: Strong evidence suggests that the powerful beneficial effect of regular physical activity for preventing (or treating) a large range of disorders might also rely on ROS-mediated signaling. Within a contracting muscle, ROS signaling may control exosomes and myokines secretion. In remote tissues, exercise generates regular and synchronized ROS waves, creating a transient pro-oxidative environment in many cells. These new concepts integrate exercise, ROS-mediated signaling, and the widespread health benefits of exercise.

Molecular Predictors for Advanced Papillary Thyroid Carcinoma Recurrence.

Despite its indolent course, one-third of the papillary thyroid carcinoma (PTC) cases relapses, which directly impact on the quality of patients' lives. The molecular predictors of recurrence of PTC are poorly defined. We aimed at evaluating the long-term (10-20 years) prognostic value of aggressiveness markers in advanced PTC. To this end, immunohistochemistry for BRAFV600E, Estrogen receptor α, Progesterone receptor, Ki-67, and E-cadherin were performed in 53 primary advanced PTC from an up to 20 years follow-up patients from a well-characterized Brazilian cohort. Categorical data were summarized using frequencies and groups were compared using Chi-squared and Fisher's exact tests. The expressions of the aggressiveness markers were associated with clinical-pathological data using the single-covariate logistic regression analysis. The Kaplan-Meier method with the Log-rank and Peto tests was used to estimate the probability of PTC-free survival. Persistence and recurrence (active disease) were associated with age (≥55 years), tumor size (>2 cm), extrathyroidal extension, local aggressiveness, macroscopic lymph node metastasis, and TNM stage at initial treatment. The BRAFV600E mutation status was associated with extrathyroidal extension, local aggressiveness, and inversely associated with distant metastasis at initial treatment. All progesterone receptor-positive patients had active disease and displayed a shorter time of PTC-free survival than the negative ones using the Kaplan-Meir analysis (p = 0.001, Log Rank; p = 0.005, Peto). Loss of E-cadherin expression was associated with an increase in the probability of active disease (OR = 3.75). BRAFV600E could be useful as a biomarker of local aggressiveness, while PR positive and E-cadherin loss of expression could predict the recurrence of advanced PTC.

Metformin ameliorates body mass gain and early metabolic changes in ovariectomized rats.

Estradiol has been used to prevent metabolic diseases, bone loss and menopausal symptoms, even though it might raise the risk of cancer. Metformin is usually prescribed for type 2 diabetes mellitus and lowers food intake and body mass while improving insulin resistance and the lipid profile. Ovariectomized rats show increased body mass, insulin resistance and changes in the lipid profile. Thus, the aim of this work was to evaluate whether metformin could prevent the early metabolic dysfunction that occurs early after ovariectomy. Female Wistar rats were divided into the following groups: SHAM-operated (SHAM), ovariectomized (OVX), ovariectomized + estradiol (OVX + E2) and ovariectomized + metformin (OVX + M). Treatment with metformin diminished approximately 50% of the mass gain observed in ovariectomized animals and reduced both the serum and hepatic triglyceride levels. The hepatic levels of phosphorylated AMP-activated protein kinase (pAMPK) decreased after OVX, and the expression of the inactive form of hepatic acetyl-CoA carboxylase (ACC) was also reduced. Metformin was able to increase the levels of pAMPK in the liver of OVX animals, sustaining the balance between the inactive and total forms of ACC. Estradiol effects were similar to those of metformin but with different proportions. Our results suggest that metformin ameliorates the early alterations of metabolic parameters and rescues hepatic AMPK phosphorylation and ACC inactivation observed in ovariectomized rats.

Inhibition of Type 1 Iodothyronine Deiodinase by Bisphenol A.

Plastics are ubiquitously present in our daily life and some components of plastics are endocrine-disrupting chemicals, such as bisphenol A and phthalates. Herein, we aimed to evaluate the effect of plastic endocrine disruptors on type 1 and type 2 deiodinase activities, enzymes responsible for the conversion of the pro-hormone T4 into the biologically active thyroid hormone T3, both in vitro and in vivo. Initially, we incubated rat liver type 1 deiodinase and brown adipose tissue type 2 deiodinase samples with 0.5 mM of the plasticizers, and the deiodinase activity was measured. Among them, only BPA was capable to inhibit both type 1 and type 2 deiodinases. Then, adult male Wistar rats were treated orally with bisphenol A (40 mg/kg b.w.) for 15 days and hepatic type 1 deiodinase and brown adipose tissue type 2 deiodinase activities and serum thyroid hormone concentrations were measured. In vivo bisphenol A treatment significantly reduced hepatic type 1 deiodinase activity but did not affect brown adipose tissue type 2 deiodinase activity. Serum T4 levels were higher in bisphenol A group, while T3 remained unchanged. T3/T4 ratio was decreased in rats treated with bisphenol A, reinforcing the idea that peripheral metabolism of thyroid hormone was affected by bisphenol A exposure. Therefore, our results suggest that bisphenol A can affect the metabolism of thyroid hormone thus disrupting thyroid signaling.

Sexual dimorphism of liver endoplasmic reticulum stress susceptibility in prepubertal rats and the effect of sex steroid supplementation.

NEW FINDINGS: What is the central question of this study? Is there sexual dimorphism in the occurrence of hepatic endoplasmic reticulum stress? What is the main finding and its importance? The transition from prepubertal to the adult age is associated with an increase in the unfolded protein response markers in the liver of male rats, which is probably due to an increase in serum testosterone levels. ABSTRACT: Male rodents present a higher predisposition to obesity and insulin resistance than females. These disorders have been associated with endoplasmic reticulum (ER) stress. To investigate a possible sexual dimorphism in the hepatic occurrence of ER stress, we evaluated the expression of ER stress markers in the livers of male and female rats in two phases of sexual development. In the first experimental model, male and female prepubertal and adult Wistar rats were used. Adult males presented higher body mass and greater mass of the adipose tissue and liver than adult females. Prepubertal animals presented no differences in these parameters between males and females. Despite this finding, the hepatic expression levels of Bip, Ire1α and Xbp1s mRNA were lower in prepubertal males than in females, while in adult animals, they did not differ between sexes. In the second experimental model, we anticipated the sexually mature phase by daily injections of testosterone propionate for 10 days in prepubertal males or by daily injections of oestradiol benzoate for 7 days in prepubertal females. Oestradiol administration in prepubertal females did not change any of the parameters evaluated. Testosterone administration to prepubertal males led to a higher body mass and greater expression of Bip, Ire1α, Atf4 and Xbp1s in the liver. These findings suggest that the increased ER stress predisposition observed in males during puberty is due to an increase in testosterone levels, indicating that ER stress is sexually dimorphic before puberty due to the lack of testosterone in males.

The Emerging Role of Estrogens in Thyroid Redox Homeostasis and Carcinogenesis.

Reactive oxygen species (ROS) are the most critical class of free radicals or reactive metabolites produced by all living organisms. ROS regulate several cellular functions through redox-dependent mechanisms, including proliferation, differentiation, hormone synthesis, and stress defense response. However, ROS overproduction or lack of appropriate detoxification is harmful to cells and can be linked to the development of several diseases, such as cancer. Oxidative damage in cellular components, especially in DNA, can promote the malignant transformation that has already been described in thyroid tissue. In thyrocyte physiology, NADPH oxidase enzymes produce large amounts of ROS that are necessary for hormone biosynthesis and might contribute to the high spontaneous mutation rate found in this tissue. Thyroid cancer is the most common endocrine malignancy, and its incidence is significantly higher in women than in men. Several lines of evidence suggest the sex hormone estrogen as a risk factor for thyroid cancer development. Estrogen in turn, besides being a potent growth factor for both normal and tumor thyroid cells, regulates different mechanisms of ROS generation. Our group demonstrated that the thyroid gland of adult female rats exhibits higher hydrogen peroxide (H2O2) production and lower enzymatic antioxidant defense in comparison with male glands. In this review, we discuss the possible involvement of thyroid redox homeostasis and estrogen in the development of thyroid carcinogenesis.

Brown adipose tissue remodelling induced by corticosterone in male Wistar rats.

NEW FINDINGS: What is the central question of this study? Does glucocorticoid excess disrupt brown adipose tissue (BAT) phenotype and function? What is the main finding and its importance? Glucocorticoid excess induced an extensive remodelling of interscapular BAT, resulting in a white-like phenotype in association with metabolic disturbances. Glucocorticoids might be an important modulator of BAT physiology and BAT may have a role in pathophysiology of metabolic disturbances induced by glucocorticoid excess. ABSTRACT: In mammals, brown adipose tissue (BAT) is centrally involved in energy metabolism. To test the hypothesis that glucocorticoid excess disrupts BAT phenotype and function, male Wistar rats were treated with corticosterone in drinking water for 21 days. To confirm induction of glucocorticoid excess and metabolic disturbances, adrenal weight, corticotrophin releasing hormone mRNA levels and corticosterone serum levels were measured and a glucose tolerance test and serum triacylglycerol analyses were performed. Adipose tissue deposits were excised, weighed and evaluated by a set of biochemical, histological and molecular procedures, including thin-layer chromatography, histochemistry, immunohistochemistry, quantitative real-time polymerase chain reaction, high-resolution oxygraphy, ATP synthesis and enzymatic activity measurements. The approach was successful in induction of glucocorticoid excess and metabolic disturbances. Lower body weight and increased adiposity were observed in corticosterone-treated rats. Interscapular brown adipose tissue (iBAT) showed higher sensitivity to glucocorticoids than other fat deposits. The treatment induced lipid accumulation, unilocular rearrangement, increased collagen content and decreased innervation in iBAT. Furthermore, expression of Prdm16 (P < 0.05), Ucp1 (P <0.05) and Slc7a10 (P <0.05) mRNA decreased, while expression of Fasn (P <0.05) and Lep (P <0.05) mRNA increased in brown adipose tissue. Also, the levels of UCP1 diminished (P <0.001, 2.5-fold). Finally, lower oxygen consumption (P <0.05), ATP synthesis (P <0.05) and mitochondrial content (P <0.05) were observed in iBAT of glucocorticoid-treated rats. Glucocorticoid excess induced an extensive remodelling of interscapular brown adipose tissue, resulting in a white-like phenotype in association with metabolic disturbances.

Sex differences in subcutaneous adipose tissue redox homeostasis and inflammation markers in control and high-fat diet fed rats.

The development of obesity-related metabolic disorders is more evident in male in comparison with female subjects, but the mechanisms are unknown. Several studies have shown that oxidative stress is involved in the pathophysiology of obesity, but the majority of these studies were performed with male animals. The aim of this study was to evaluate the sex-related differences in subcutaneous adipose tissue redox homeostasis and inflammation of rats chronically fed a high-fat diet. NADPH oxidase (NOX), glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase activities were evaluated in the subcutaneous adipose tissue (SC) of adult male and female rats fed either a standard chow (SCD) or a high-fat diet (HFD) for 11 weeks. NOX2 and NOX4 messenger RNA (mRNA) levels, total reduced thiols, interleukin (IL)-1ß, tumor necrosis factor α (TNF-α), and IL-6 were also determined. Higher antioxidant enzyme activities and total reduced thiol levels were detected in SC of control male compared with female rats. Chronic HFD administration increased NOX activity and NOX2 and NOX4 mRNA levels and decreased SOD and GPx activities only in male animals. IL-1ß, TNF-α, and IL-6 levels, as well as Adgre1, CD11b, and CD68 mRNA levels, were also higher in SC of males after HFD feeding. In SC of females, catalase activity was higher after HFD feeding. Taken together, our results show that redox homeostasis and inflammation of SC is sexually dimorphic. Furthermore, males show higher oxidative stress in SC after 11 weeks of HFD feeding owing to both increased reactive oxygen species (ROS) production through NOX2 and NOX4 and decreased ROS detoxification.

Similarities and Differences in the Peripheral Actions of Thyroid Hormones and Their Metabolites.

Thyroxine (T4) and 3,5,3'-triiodothyronine (T3) are secreted by the thyroid gland, while T3 is also generated from the peripheral metabolism of T4 by iodothyronine deiodinases types I and II. Several conditions like stress, diseases, and physical exercise can promote changes in local TH metabolism, leading to different target tissue effects that depend on the presence of tissue-specific enzymatic activities. The newly discovered physiological and pharmacological actions of T4 and T3 metabolites, such as 3,5-diiodothyronine (3,5-T2), and 3-iodothyronamine (T1AM) are of great interest. A classical thyroid hormone effect is the ability of T3 to increase oxygen consumption in almost all cell types studied. Approximately 30 years ago, a seminal report has shown that 3,5-T2 increased oxygen consumption more rapidly than T3 in hepatocytes. Other studies demonstrated that exogenous 3,5-T2 administration was able to increase whole body energy expenditure in rodents and humans. In fact, 3,5-T2 treatment prevents diabetic nephropathy, hepatic steatosis induced by high fat diet, insulin resistance, and weight gain during aging in Wistar male rats. The regulation of mitochondria is likely one of the most important actions of T3 and its metabolite 3,5-T2, which was able to restore the thermogenic program of brown adipose tissue (BAT) in hypothyroid rats, just as T3 does, while T1AM administration induced rapid hypothermia. T3 increases heart rate and cardiac contractility, which are hallmark effects of hyperthyroidism involved in cardiac arrhythmia. These deleterious cardiac effects were not observed with the use of 3,5-T2 pharmacological doses, and in contrast T1AM was shown to promote a negative inotropic and chronotropic action at micromolar concentrations in isolated hearts. Furthermore, T1AM has a cardioprotective effect in a model of ischemic/reperfusion injury in isolated hearts, such as occurs with T3 administration. Despite the encouraging possible therapeutic use of TH metabolites, further studies are needed to better understand their peripheral effects, when compared to T3 itself, in order to establish their risk and benefit. On this basis, the main peripheral effects of thyroid hormones and their metabolites in tissues, such as heart, liver, skeletal muscle, and BAT are discussed herein.

DUOX1 Silencing in Mammary Cell Alters the Response to Genotoxic Stress.

DUOX1 is an H2O2-generating enzyme related to a wide range of biological features, such as hormone synthesis, host defense, cellular proliferation, and fertilization. DUOX1 is frequently downregulated in lung and liver cancers, suggesting a tumor suppressor role for this enzyme. Here, we show that DUOX1 expression is decreased in breast cancer cell lines and also in breast cancers when compared to the nontumor counterpart. In order to address the role of DUOX1 in breast cells, we stably knocked down the expression of DUOX1 in nontumor mammary cells (MCF12A) with shRNA. This led to higher cell proliferation rates and decreased migration and adhesion properties, which are typical features for transformed cells. After genotoxic stress induced by doxorubicin, DUOX1-silenced cells showed reduced IL-6 and IL-8 secretion and increased apoptosis levels. Furthermore, the cell proliferation rate was higher in DUOX1-silenced cells after doxorubicin medication in comparison to control cells. In conclusion, we demonstrate here that DUOX1 is silenced in breast cancer, which seems to be involved in breast carcinogenesis.

Intense physical exercise potentiates glucose inhibitory effect over food intake of male Wistar rats.

NEW FINDINGS: What is the central question of this study? How does an acute session of exercise affect food intake of male Wistar rats? What is the main finding and its importance? Food intake in male Wistar rats is decreased in the first hour after physical exercise independent of the intensity. Moreover, high-intensity exercise potentiates the anorexic effect of peripheral glucose administration. This work raises new feeding-related targets that would explain how exercise drives body weight loss. ABSTRACT: Obesity has emerged as a critical metabolic disorder in modern society. An adequate lifestyle with a well-oriented programme of diet and physical exercise (PE) can prevent or potentially even cure obesity. Additionally, PE might lead to weight loss by increasing energy expenditure and decreasing hunger perception. In this article, we hypothesize that an acute exercise session would potentiate the glucose inhibitory effects on food intake in male Wistar rats. Our data show that moderate- or high-intensity PE significantly decreased food intake, although no changes in the expression of feeding-related neuropeptide in the arcuate nucleus of the hypothalamus were found. Exercised animals demonstrated a reduced glucose tolerance and increased blood insulin concentration. Intraperitoneal administration of glucose decreased food intake in control animals. In the animals submitted to moderate-intensity PE, the decrease in food intake promoted by glucose was similar to controls; however, an interaction was observed when glucose was injected in the high-intensity PE group, in which food intake was significantly lower than the effect produced by glucose alone. A different pattern of expression was observed for the monocarboxylate transporter isoforms (MCT1, 2 and 4) and 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFBP3) in the hypothalamus, which was dependent on the exercise intensity. In conclusion, PE decreases food intake independently of the intensity. However, an interaction between PE and the anorexic effect of glucose is only observed when a high-intensity exercise is performed. These data show an essential role of exercise intensity in the modulation of the glucose inhibitory effect on food intake.

NKX2.5 is expressed in papillary thyroid carcinomas and regulates differentiation in thyroid cells.

BACKGROUND: NKX2.5 is a transcription factor transiently expressed during thyroid organogenesis. Recently, several works have pointed out the oncogenic role of NKX2.5 in a variety of tumors. We therefore hypothesized that NKX2.5 could also play a role in thyroid cancer. METHODS: The validation of NKX2.5 expression was assessed by immunohistochemistry analysis in a Brazilian case series of 10 papillary thyroid carcinoma (PTC) patients. Then, the long-term prognostic value of NKX2.5 and its correlation with clinicopathologic features of 51 PTC patients was evaluated in a cohort with 10-years follow-up (1990-1999). Besides, the effect of NKX2.5 overexpression on thyroid differentiation markers and function was also investigated in a non-tumor thyroid cell line (PCCL3). RESULTS: NKX2.5 was shown to be expressed in most PTC samples (8/10, case series; 27/51, cohort). Patients who had tumors expressing NKX2.5 showed lower rates of persistence/recurrence (p = 0.013). Overexpression of NKX2.5 in PCCL3 cells led to: 1) downregulation of thyroid differentiation markers (thyrotropin receptor, thyroperoxidase and sodium-iodide symporter); 2) reduced iodide uptake; 3) increased extracellular H2O2 generation, dual oxidase 1 mRNA levels and activity of DuOx1 promoter. CONCLUSIONS: In summary, NKX2.5 is expressed in most PTC samples analyzed and its presence correlates to better prognosis of PTC. In vitro, NKX2.5 overexpression reduces the expression of thyroid differentiation markers and increases ROS production. Thus, our data suggests that NKX2.5 could play a role in thyroid carcinogenesis.

Conformation of the N-Terminal Ectodomain Elicits Different Effects on DUOX Function: A Potential Impact on Congenital Hypothyroidism Caused by a H2O2 Production Defect.

BACKGROUND: Dual oxidases (DUOX1 and DUOX2) were initially identified as H2O2 sources involved in thyroid hormone synthesis. Congenital hypothyroidism (CH) resulting from inactivating mutations in the DUOX2 gene highlighted that DUOX2 is the major H2O2 provider to thyroperoxidase. The role of DUOX1 in the thyroid remains unknown. A recent study suggests that it could compensate for DUOX2 deficiency in CH. Both DUOX enzymes and their respective maturation factors DUOXA1 and DUOXA2 form a stable complex at the cell surface, which is fundamental for their enzymatic activity. Recently, intra- and intermolecular disulfide bridges were identified that are essential for the structure and the function of the DUOX2-DUOXA2 complex. This study investigated the involvement of cysteine residues conserved in DUOX1 toward the formation of disulfide bridges, which could be important for the function of the DUOX1DUOXA1 complex. METHODS: To analyze the role of these cysteine residues in both the targeting and function of dual oxidase, different human DUOX1 mutants were constructed, where the cysteine residues were replaced with glycine. The effect of these mutations on cell surface expression and H2O2-generating activity of the DUOX1-DUOXA1 complex was analyzed. RESULTS: Mutations of two cysteine residues (C118 and C1165), involved in the formation of the intramolecular disulfide bridge between the N-terminal ectodomain and one of the extracellular loops, mildly altered the function and the targeting of DUOX1, while this bridge is crucial for DUOX2 function. Unlike DUOXA2, with respect to DUOX2, the stability of the maturation factor DUOXA1 is not dependent on the oxidative folding of DUOX1. Only mutation of C579 induced a strong alteration of both targeting and function of the oxidase by preventing the covalent interaction between DUOX1 and DUOXA1. CONCLUSION: An intermolecular disulfide bridge rather than an intramolecular disulfide bridge is important for both the trafficking and H2O2-generating activity of the DUOX1-DUOXA1 complex.