NRF2 and Thioredoxin Reductase 1 as Modulators of Interactions between Zinc and Selenium.

Background: Selenium and zinc are essential trace elements known to regulate cellular processes including redox homeostasis. During inflammation, circulating selenium and zinc concentrations are reduced in parallel, but underlying mechanisms are unknown. Accordingly, we modulated the zinc and selenium supply of HepG2 cells to study their relationship.

Selenium-Enriched Bacteria Mitigate the Age-Associated Degeneration of Cholinergic Neurons in .

Selenium (Se) is an essential trace element for humans and animals, but high-dose supplementation with Se compounds, most notably selenite, may exert cytotoxic and other adverse effects. On the other hand, bacteria, including (), are capable of reducing selenite to red elemental Se that may serve as a safer Se source. Here, we examined how a diet of Se-enriched bacteria affected vital parameters and age-associated neurodegeneration in the model organism ().

Long-term suboptimal dietary trace element supply does not affect trace element homeostasis in murine cerebellum.

The ageing process is associated with alterations of systemic trace element (TE) homeostasis increasing the risk, e.g. neurodegenerative diseases.

Selenium-binding protein 1 (SELENBP1) is a copper-dependent thiol oxidase.

Selenium-binding protein 1 (SELENBP1) was reported to act as a methanethiol oxidase (MTO) in humans, catalyzing the conversion of methanethiol to hydrogen peroxide, hydrogen sulfide and formaldehyde. Here, we identify copper ions as essential to this novel MTO activity. Site-directed mutagenesis of putative copper-binding sites in human SELENBP1 produced as recombinant protein in E.

Measurement of trace elements in murine liver tissue samples: Comparison between ICP-MS/MS and TXRF.

Background: Trace elements exhibit essential functions in many physiological processes. Thus, for research focusing on trace element homeostasis and metabolism analytical methods allowing for multi-element analyses are fundamental. Small sample amounts may be a big challenge in trace element analyses especially if also other end points want to be addressed in the same sample.

Selenium homeostasis in human brain cells: Effects of copper (II) and Se species.

Background: Both essential trace elements selenium (Se) and copper (Cu) play an important role in maintaining brain function. Homeostasis of Cu, which is tightly regulated under physiological conditions, seems to be disturbed in Alzheimer´s (AD) and Parkinson´s disease (PD) patients. Excess Cu promotes the formation of oxidative stress, which is thought to be a major cause for development and progression of neurological diseases (NDs).

The Nutritional Supply of Iodine and Selenium Affects Thyroid Hormone Axis Related Endpoints in Mice.

Selenium and iodine are the two central trace elements for the homeostasis of thyroid hormones but additional trace elements such as iron, zinc, and copper are also involved. To compare the primary effects of inadequate intake of selenium and iodine on the thyroid gland, as well as the target organs of thyroid hormones such as liver and kidney, mice were subjected to an eight-week dietary intervention with low versus adequate selenium and iodine supply. Analysis of trace element levels in serum, liver, and kidney demonstrated a successful intervention.

Copper interferes with selenoprotein synthesis and activity.

Selenium and copper are essential trace elements for humans, needed for the biosynthesis of enzymes contributing to redox homeostasis and redox-dependent signaling pathways. Selenium is incorporated as selenocysteine into the active site of redox-relevant selenoproteins including glutathione peroxidases (GPX) and thioredoxin reductases (TXNRD). Copper-dependent enzymes mediate electron transfer and other redox reactions.

A quick and simple method for the determination of six trace elements in mammalian serum samples using ICP-MS/MS.

In order to assess the individual trace element status of humans for either medical or scientific purposes, amongst others, blood serum levels are determined. Furthermore, animal models are used to study interactions of trace elements. Most published methods require larger amounts (500-1000 μL) of serum to achieve a reliable determination of multiple trace elements.

Importance of propionate for the repression of hepatic lipogenesis and improvement of insulin sensitivity in high-fat diet-induced obesity.

Scope: The SCFA acetate (Ac) and propionate (Pr) are major fermentation products of dietary fibers and provide additional energy to the host. We investigated short- and long-term effects of dietary Ac and Pr supplementation on diet-induced obesity and hepatic lipid metabolism.

Methods And Results: C3H/HeOuJ mice received high-fat (HF) diets supplemented with 5% SCFA in different Ac:Pr ratios, a high acetate (HF-HAc; 2.

Differential acute effects of selenomethionine and sodium selenite on the severity of colitis.

The European population is only suboptimally supplied with the essential trace element selenium. Such a selenium status is supposed to worsen colitis while colitis-suppressive effects were observed with adequate or supplemented amounts of both organic selenomethionine (SeMet) and inorganic sodium selenite. In order to better understand the effect of these selenocompounds on colitis development we examined colonic phenotypes of mice fed supplemented diets before the onset of colitis or during the acute phase.

Selenoprotein W as biomarker for the efficacy of selenium compounds to act as source for selenoprotein biosynthesis.

Selenium is an essential trace element and, like all elements, present in many different compounds with unequivocal functions. This fact is only sporadically mentioned when recommended intake or supplementation is indicated just as "selenium." In mammals, selenium is an integral part of selenoproteins as selenocysteine.

Selenium in the redox regulation of the Nrf2 and the Wnt pathway.

Selenium deficiency is known to increase cancer risk by so far unclear mechanisms. Selenium exerts its biological effects via selenocysteine as an integral part of selenoproteins. Certain selenoproteins have redox properties, thereby providing a tool to regulate hydroperoxide-mediated signaling.

Physiological functions of GPx2 and its role in inflammation-triggered carcinogenesis.

Mammalian glutathione peroxidases (GPxs) are reviewed with emphasis on the role of the gastrointestinal GPx2 in tumorigenesis. GPx2 ranks high in the hierarchy of selenoproteins, corroborating its importance. Colocalization of GPx2 with the Wnt pathway in crypt bases of the intestine and its induction by Wnt signals point to a role in mucosal homeostasis, but GPx2 might also support tumor growth when increased by a dysregulated Wnt pathway.

The yin and yang of nrf2-regulated selenoproteins in carcinogenesis.

The NF-E2-related factor-2 (Nrf2) is a transcription factor which regulates the major cellular defense systems and thereby contributes to the prevention of many diseases including cancer. Selenium deficiency is associated with a higher cancer risk making also this essential trace element a promising candidate for cancer prevention. Two selenoproteins, thioredoxin reductase-1 (TrxR1) and glutathione peroxidase-2 (GPx2), are targets for Nrf2.