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20 result(s) for "Miranda-Alves, Leandro"
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TSH Receptor Reduces Hemoglobin S Polymerization and Increases Deformability and Adhesion of Sickle Erythrocytes
SCD is a hereditary disorder caused by genetic mutation in the beta-globin gene, resulting in abnormal hemoglobin, HbS that forms sickle-shaped erythrocytes under hypoxia. Patients with SCD have endocrine disorders and it was described that 7% of these patients have clinical hypothyroidism. Recent studies have shown that mature erythrocytes possess TSH receptors. Thus, we aimed to assess the effects of TSH on SCD erythrocytes. The experiments were conducted using different concentrations of TSH (1, 2, 3, and 5 mIU/L). In HbS polymerization assay, erythrocytes were exposed to TSH in hypoxia to induce polymerization, and measurements were taken for 30 minutes. The deformability assay was made using Sephacryl-S 500 columns to separate deformable from nondeformable cells. Static adhesion test utilized thrombospondin to assess erythrocyte adhesion in the presence of TSH. TSH at all contractions were able to reduce polymerization of HbS and increase deformability. The static adhesion of erythrocytes at the lowest concentrations of 1 and 2 mIU/L were increased, but at higher contractions of 3 and 5 mIU/L, static adhesion was not modulated. The results suggest that TSH has potential involvement in the pathophysiology of sickle cell disease by inhibiting HbS polymerization, positively modulating deformability and impacting static adhesion to thrombospondin.
Environmental Health and Toxicology: Immunomodulation Promoted by Endocrine-Disrupting Chemical Tributyltin
Tributyltin (TBT) is an environmental contaminant present on all continents, including Antarctica, with a potent biocidal action. Its use began to be intensified during the 1960s. It was effectively banned in 2003 but remains in the environment to this day due to several factors that increase its half-life and its misuse despite the bans. In addition to the endocrine-disrupting effect of TBT, which may lead to imposex induction in some invertebrate species, there are several studies that demonstrate that TBT also has an immunotoxic effect. The immunotoxic effects that have been observed experimentally in vertebrates using in vitro and in vivo models involve different mechanisms; mainly, there are alterations in the expression and/or secretion of cytokines. In this review, we summarize and update the literature on the impacts of TBT on the immune system, and we discuss issues that still need to be explored to fill the knowledge gaps regarding the impact of this endocrine-disrupting chemical on immune system homeostasis.
Lycopene and Beta-Carotene Induce Growth Inhibition and Proapoptotic Effects on ACTH-Secreting Pituitary Adenoma Cells
Pituitary adenomas comprise approximately 10-15% of intracranial tumors and result in morbidity associated with altered hormonal patterns, therapy and compression of adjacent sella turcica structures. The use of functional foods containing carotenoids contributes to reduce the risk of chronic diseases such as cancer and vascular disorders. In this study, we evaluated the influence of different concentrations of beta-carotene and lycopene on cell viability, colony formation, cell cycle, apoptosis, hormone secretion, intercellular communication and expression of connexin 43, Skp2 and p27(kip1) in ACTH-secreting pituitary adenoma cells, the AtT20 cells, incubated for 48 and 96 h with these carotenoids. We observed a decrease in cell viability caused by the lycopene and beta-carotene treatments; in these conditions, the clonogenic ability of the cells was also significantly decreased. Cell cycle analysis revealed that beta-carotene induced an increase of the cells in S and G2/M phases; furthermore, lycopene increased the proportion of these cells in G0/G1 while decreasing the S and G2/M phases. Also, carotenoids induced apoptosis after 96 h. Lycopene and beta-carotene decreased the secretion of ACTH in AtT20 cells in a dose-dependent manner. Carotenoids blocked the gap junction intercellular communication. In addition, the treatments increased the expression of phosphorylated connexin43. Finally, we also demonstrate decreased expression of S-phase kinase-associated protein 2 (Skp2) and increased expression of p27(kip1) in carotenoid-treated cells. These results show that lycopene and beta-carotene were able to negatively modulate events related to the malignant phenotype of AtT-20 cells, through a mechanism that could involve changes in the expression of connexin 43, Skp2 and p27(kip1); and suggest that these compounds might provide a novel pharmacological approach to the treatment of Cushing's disease.
Environmental Endocrinology: Parabens Hazardous Effects on Hypothalamic–Pituitary–Thyroid Axis
Parabens are classified as endocrine-disrupting chemicals (EDCs) capable of interfering with the normal functioning of the thyroid, affecting the proper regulation of the biosynthesis of thyroid hormones (THs), which is controlled by the hypothalamic–pituitary–thyroid axis (HPT). Given the crucial role of these hormones in health and the growing evidence of diseases related to thyroid dysfunction, this review looks at the effects of paraben exposure on the thyroid. In this study, we considered research carried out in vitro and in vivo and epidemiological studies published between 1951 and 2023, which demonstrated an association between exposure to parabens and dysfunctions of the HPT axis. In humans, exposure to parabens increases thyroid-stimulating hormone (TSH) levels, while exposure decreases TSH levels in rodents. The effects on THs levels are also poorly described, as well as peripheral metabolism. Regardless, recent studies have shown different actions between different subtypes of parabens on the HPT axis, which allows us to speculate that the mechanism of action of these parabens is different. Furthermore, studies of exposure to parabens are more evident in women than in men. Therefore, future studies are needed to clarify the effects of exposure to parabens and their mechanisms of action on this axis.
ATR1 Angiotensin II Receptor Reduces Hemoglobin S Polymerization, Phosphatidylserine Exposure, and Increases Deformability of Sickle Cell Disease Erythrocytes
Angiotensin II (Ang II) regulates blood volume and stimulates erythropoiesis through AT1 (ATR1) and AT2 (ATR2) receptors, found in multiple tissues, including erythrocytes. Sickle cell disease (SCD) patients present altered Ang II levels. Hemoglobin S polymerization, deformability and phosphatidylserine translocation are important features of mature erythrocytes, therefore, our hypothesis is Ang II affects these parameters and, if it does, what would be the influence of AT1R and AT2R on these effects. A polymerization assay (PA), deformability, and annexin V binding were performed in SCD erythrocytes samples adding Ang II, ATR1 antagonist (losartan or eprosartan), and ATR2 antagonist (PD123319). Through the PA test, we observed a dose-dependent polymerization inhibition effect when comparing Ang II to control. Losartan did not affect the level or the rate of Ang II inhibition, while PD123319 showed an increased level of protection against polymerization, and eprosartan brought levels back to control. Ang II was able to reduce the translocation of phosphatidylserine from the inner to the outer leaflet, a marker of eryptosis, in the presence of PD123319. Also, ATR1 showed a positive effect increasing deformability. Our data shows that ATR1 is important for maintenance of erythrocyte physiological function in SCD and for prolonging its life.
Aggressive nonfunctioning pituitary neuroendocrine tumors
Nonfunctioning pituitary neuroendocrine tumors (NF-PitNETs) are tumors that are not associated with clinical evidence of hormonal hypersecretion. According to the World Health Organization (WHO), there are some subtypes of PitNETs that exhibit more aggressive behavior than others. Among the types of potentially aggressive PitNETs, three are nonfunctional: silent sparsely granulated somatotropinomas, silent corticotropinomas, and poorly differentiated PIT-1 lineage tumors. Several biological markers have been investigated in NF-PitNETs. However, there is no single biomarker able to independently predict aggressive behavior in NF-PitNETs. Thus, a more complex and multidisciplinary proposal of a comprehensive definition of aggressive NF-PitNETs is necessary. Here, we suggest a combined and more complete criterion for the NF-PitNETs classification. We propose that aggressiveness is due to a multifactorial combination, and we emphasize the need to include new emerging markers that are involved in the aggressiveness of NF-PitNETs and the need to identify.
Early Caffeine Exposure Causes Metabolic and Hormonal Changes Differently According to the Window of Exposure (Gestation or Lactation), Sex, and Age in a Rat Model
Background/Objectives: Many women report restrictions on caffeine intake during gestation, but some of these restrictions are withdrawn during the lactation period. Given that both periods have elevated epigenetic plasticity, our aim was to compare the effects of caffeine exposure during each isolated period on offspring metabolism and susceptibility to obesity in response to metabolic overload. Methods: Pregnant Wistar rats received orogastric caffeine (CAF) (25 mg/kg/day) or vehicle during gestation (CAF G) or lactation (CAF L) periods. We evaluated the body mass, adiposity, hormone levels, and food behavior of offspring of both sexes at different ages. Adult animals were subjected to metabolic overload, with fructose solution (10%) offered for ten days. Results/Discussion: CAF G and CAF L dams presented lower T3 levels (−70 and −52%) because of reduced TSH activity in the thyroid gland (−28 and −29%), despite unchanged gland morphology. At weaning, CAF G and CAF L males presented lower T3 levels (−75 and −80%), as did CAF L females (−85%). At puberty, females in the CAF L group showed glucose intolerance. In adulthood, CAF G males exhibited a greater preference for palatable food. In addition, CAF G and CAF L males showed increased feed efficiency, suggesting a greater susceptibility to obesity development. To test this susceptibility, the animals were subjected to fructose overload. Indeed, we observed that despite the absence of a fructose effect in the control group, male CAF G and female CAF L animals showed greater adiposity in response to fructose overload (+43% and +37%, respectively). Conclusions: Caffeine exposure during lactation increases the risk of obesity development among female offspring. However, for male offspring, gestation seems more critical.
Unraveling molecular targets of bisphenol A and S in the thyroid gland
Bisphenol A (BPA) is a well-known endocrine disruptor with several effects on reproduction, development, and cancer incidence, and it is highly used in the plastic industry. Bisphenol S (BPS) was proposed as an alternative to BPA since it has a similar structure and can be used to manufacture the same products. Some reports show that BPA interferes with thyroid function, but little is known about the involvement of BPS in thyroid function or how these molecules could possibly modulate at the same time the principal genes involved in thyroid physiology. Thus, the aims of this work were to evaluate in silico the possible interactions of BPA and BPS with the thyroid transcription factors Pax 8 and TTF1 and to study the actions in vivo of these compounds in zebrafish thyroid gene expression. Adult zebrafish treated with BPA or BPS showed that sodium iodide symporter, thyroglobulin, and thyroperoxidase genes were negatively or positively regulated, depending on the dose of the exposure. Human Pax 8 alignment with zebrafish Pax 8 and Rattus norvegicus TTF1 alignment with zebrafish TTF1 displayed highly conserved regions in the DNA binding sites. Molecular docking revealed the in silico interactions between the protein targets Pax 8 and TTF1 with BPA and BPS. Importance of some amino acids residues is highlighted and ratified by literature. There were no differences between the mean energy values for BPA docking in Pax 8 or TTF1. However, BPS energy values were lower in TTF1 docking compared to Pax 8 values. The number of amino acids on the protein interface was important for Pax 8 but not for TTF1. The main BPA interactions with proteins occurred through Van der Waals forces and pi-alkyl and alkyl interactions, while BPS interactions mainly occurred through carbon hydrogen bonds and conventional hydrogen bonds in addition to Van der Waals forces and pi-alkyl interactions. These data point to a possible interaction of BPA and BPS with Pax 8 and TTF1.